AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PHOENIX AZ 1040 AM MST FRI MAR 23 2007 .SYNOPSIS... A STRONG LOW PRESSURE SYSTEM TO OUR SOUTH WILL MOVE SLOWLY EAST ACROSS NORTHERN MEXICO TODAY. EXPECT A GOOD CHANCE FOR SHOWERS AND THUNDERSTORMS TODAY AND TONIGHT...WITH HEAVIEST PRECIPITATION LIKELY FROM PHOENIX EASTWARD. THE CHANCE FOR SHOWERS WILL LINGER INTO SATURDAY OVER SOUTH-CENTRAL ARIZONA. HOWEVER...HIGHER PRESSURE FROM THE PACIFIC WILL MOVE CLOSER TO ARIZONA AS THE WEEKEND PROGRESSES... BRINGING A SLOW DRYING TREND. EXPECT A WARMING TREND TO COMMENCE OUT WEST SATURDAY...AND OVER ALL OF THE FORECAST AREA BY SUNDAY...WITH ABOVE NORMAL DAYTIME HIGHS SUNDAY THROUGH TUESDAY. ANOTHER STRONG WEATHER DISTURBANCE AND ASSOCIATED COLD FRONT WILL PRODUCE WINDY CONDITIONS NEXT TUESDAY...AND USHER IN COOLER TEMPERATURES NEXT WEDNESDAY. && .SHORT TERM... TODAY THROUGH SUNDAY... UPPER LOW OVER NORTHERN GULF OF CALIFORNIA AS OF 16Z...AND WAS MOVING SLOWLY TOWARD THE EAST. FLOW ALOFT HAS BACKED OVERNIGHT...AND IS NOW FROM THE SOUTHEAST ACROSS SOUTH-CENTRAL AZ. UPPER LOW IS PROGGED TO MOVE SLOWLY TOWARD THE NORTH AND EAST TODAY...BE OVER FAR SOUTHEAST AZ BY MIDNIGHT...THEN ACCELERATE AS IT MOVES NORTHEAST AND AWAY FROM OUR FORECAST AREA ON SATURDAY. HOWEVER...WEAK RESIDUAL TROUGHING REMAINS OVER OUR REGION ALL DAY SATURDAY. AS OF 10 AM...SHWRS AND ISOLATED TRW WERE OCCURRING FROM EASTERN MARICOPA COUNTY ACROSS NORTHEAST PINAL COUNTY INTO SOUTHERN GILA COUNTY. SOME TEMPORARY CLEARING WAS NOTED TO THE REAR OF THIS BAND OF SHOWERS AND STORMS...MAINLY OVER SOUTHEAST PINAL COUNTY AND MUCH OF PIMA COUNTY. COMBINATION OF TEMPORARY CLEARING TO OUR SOUTH... COOLING MID LEVEL TEMPS (500 MB TEMP DOWN TO -22C OVER AND SOUTH OF PHOENIX ACCORDING TO THE RUC)...AND CURRENT DEVELOPMENT OF CUMULUS CLOUD STREETS OVER EASTERN PIMA COUNTY BODES WELL FOR THUNDERSTORMS TO REDEVELOP TO THE SOUTH AND EAST OF OUR CWA TODAY...WITH STORMS PROPAGATING OVER PORTIONS OF SOUTH-CENTRAL AZ FROM MID-LATE AFTERNOON TODAY INTO TONIGHT. UPPER FORCING...IN TERMS OF OMEGA AND DIVERGENCE...IS NOT IMPRESSIVE LIKE IT WAS YESTERDAY AFTERNOON /EVENING...WHICH SUGGESTS AREAL AVERAGE PRECIP OVER S-CNTRL AZ WILL BE LOWER TODAY/TONIGHT. HOWEVER...FAVORABLE THERMODYNAMICS (MIXED-LAYER LI -2 TO -4C) AND TRACK OF UPPER LOW SUPPORT IDEA THAT PORTIONS OF SOUTH-CENTRAL AZ COULD PICK UP DECENT ADDITIONAL RAINFALL...THOUGH THE AMOUNTS WILL VARY WIDELY FROM LOCATION TO LOCATION (UNLIKE YESTERDAY...WHEN MOST OF S-CNTRL AZ PICKED UP ONE HALF TO SLIGHTLY OVER 1 INCH OF RAIN). MEANWHILE...WRAPAROUND CLOUD BAND AND LIGHT SHOWERS EXISTED OVER MUCH OF FAR SOUTHEAST CALIFORNIA AND FAR WESTERN AZ THIS MORNING...WHERE FLOW ALOFT IS FROM THE NORTHEAST. CLOUD/SHWR PLUME EXTENDS WELL NORTH AND EAST OF OUR CWA...SO AGREE WITH LATEST GFS THAT THIS PORTION OF THE CWA WILL EXPERIENCE PERSISTENT CLOUD COVER AND MAINLY LIGHT RAIN SHOWERS TODAY...THOUGH AN ISOLATED THUNDERSTORM IS POSSIBLE. I HAVE TRIMMED SEVERAL DEGREES OFF FORECAST MAX TEMPS FOR THIS AREA FOR TODAY GIVEN PREVAILING WX CONDITIONS. ONE OTHER ITEM...GIVEN THE VERY HIGH BOUNDARY LAYER MOISTURE LEVELS...AND POSSIBILITY OF SOME BREAKS IN THE OVERCAST TONIGHT INTO SATURDAY AM...CANNOT RULE OUT SOME PATCHY FOG. HAVE NOT INCLUDED THAT ON WX GRIDS THIS AM DUE TO EXPECTED LOCALIZED NATURE OF THE FOG...BUT IT IS SOMETHING THAT WILL NEED TO BE MONITORED. FROM PREVIOUS DISCUSSION...AS THE LOW ZIPS NEWD INTO COLORADO BY SATURDAY AFTN...THERE WILL BE A DECREASING CLOUDS AND POPS FROM THE WEST...WITH WRAP AROUND MOISTURE GRADUALLY THINNING OVER SOUTH-CENTRAL AZ...BUT THERE WILL STILL BE A GOOD CHANCE FOR SHOWERS AND A POSSIBLE THUNDERSTORM IN ZONE 24. HIGH TEMPS WILL MODERATE SLIGHTLY OVER THE CENTRAL DESERTS SAT AND RISE SEVERAL DEGREES OVER SERN CA AND THE WESTERN DESERTS AS SUNSHINE INCREASES. HIGHER PRESSURE WILL BUILD IN FROM THE WEST SUNDAY FOR DRY AND SOMEWHAT WARMER CONDITIONS. && .LONG TERM... SUNDAY THROUGH THURSDAY... DRY PATTERN. STRONG SHORT WAVE WILL TRAVERSE THE FORECAST AREA TUESDAY-WEDNESDAY. THIS WILL ALSO RESULT IN A SIGNIFICANT WIND EVENT...WITH RATHER TIGHT LOW LEVEL WINDS (AT 700MB GFS SHOWS 40-50KTS BY MID DAY TUESDAY)...AND A VERY WINDY SCENARIO COULD LEAD TO FIRE WEATHER CONCERNS...ESPECIALLY OVER FAR SE CAL AS SYSTEM ADVECTS DRY AIR OVER THE REGION. SEE FIRE WX DISCUSSION BELOW FOR DETAILS. AFTER A DECENT WARMUP SUNDAY-TUESDAY NOTICEABLY COOLER WEATHER IS LIKELY ON WEDNESDAY...WITH SOME MODERATION IN TEMPS AFTER THAT TIME. && AVIATION... SHOWERS WITH EMBEDDED -TSRA WILL CONTINUE TO DRIFT TOWARD THE NORTH AND NORTHWEST THROUGH THE AFTERNOON. SMALL HAIL AND GUSTY WINDS ARE POSSIBLE WITH THE STRONGER STORMS AS PRECIPITATION BANDS CONTINUE TO ROTATE THROUGH SOUTHERN AZ AND SE CA AROUND THE UPPER BAJA LOW. CIGS AS LOW AS 3000 FEET AND VSBYS DOWN TO 3-4 SM MAY PERIODICALLY OCCUR THROUGHOUT THE DAY...ESPECIALLY IN AND NEAR STRONG THUNDERSTORMS. SEE TAFS PHXTAFPHX...PHXTAFIWA...PHXTAFYUM...LAXTAFBLH AND LAXTAFIPL FOR MORE DETAILED INFORMATION. AVIATION DISCUSSION IS NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... EARLY NEXT WEEK (TUESDAY-WEDNESDAY)...AN INTENSE LOW PRESSURE SYSTEM WILL SWING THROUGH THE GREAT BASIN AND NORTHERN AZ GENERATING STRONG GUSTY WEST WINDS REGION-WIDE. WINDY CONDITIONS WILL BE LIKELY...AND IF HUMIDITIES AND FUEL MOISTURES REMAIN LOW...A CRITICAL FIRE WEATHER DAY WILL BE POSSIBLE...ESPECIALLY OVER FAR SE CALIFORNIA AND WRN AZ WHERE LESS PRECIPITATION OCCURRED WITH CURRENT STORM SYSTEM. ALL INTERESTED AGENCIES ARE ENCOURAGED TO MONITOR THE LATEST FIRE WEATHER FORECASTS AND DISCUSSIONS. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...NONE. CA...NONE. && $$ NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT WEATHER.GOV/PHOENIX /DG/11/10/MEYERS/ROGERS az AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PHOENIX AZ 945 AM MST THU MAR 22 2007 .SYNOPSIS... A STRONG PACIFIC LOW PRESSURE SYSTEM WAS LOCATED JUST OFF THE NORTHERN BAJA CALIFORNIA COAST THIS MORNING. IT WILL MOVE VERY SLOWLY EAST ACROSS NORTHERN MEXICO FRIDAY INTO SATURDAY. THIS STORM SYSTEM WILL BRING INCREASING CLOUDINESS...COOLER DAYTIME HIGHS...AND PERIODS OF SHOWERS AND THUNDERSTORMS TODAY THROUGH SATURDAY...WITH THE BEST CHANCE FOR PRECIPITATION OVER SOUTH-CENTRAL ARIZONA. HIGHER PRESSURE ALOFT FROM THE PACIFIC WILL BRING DRY WEATHER WITH SOME RECOVERY OF TEMPERATURES SUNDAY AND MONDAY. ANOTHER RATHER STRONG WEATHER DISTURBANCE WILL PRODUCE BREEZY TO WINDY CONDITIONS ALONG WITH SOME COOLING NEXT TUESDAY AND WEDNESDAY. && .SHORT TERM... TODAY THROUGH SATURDAY... 12Z POSITION OF CLOSED LOW WAS NEAR 30N/117W WITH SEVERAL VORTICITY CENTERS ROTATING AROUND ITS PERIMETER. NAM/GFS SOLUTIONS APPEARED TO BE SOMEWHAT SOUTH OF LATEST RUC...WITH ALL MODELS INDICATING THE STRONGEST VORT CENTER SOUTH OF THE LOW. THE 500MB WIND SPEEDS WERE ALSO STRONGEST AROUND THE SOUTHERN QUADRANTS OF THE LOW...50-70KTS. AFTER SUNRISE THE CONVECTION PICKED UP IN OUR CWA...AND CONTINUED TO DRIFT INTO YAVAPAI COUNTY. BY FAR THE HEAVIEST PRECIP WAS THROUGH SOUTHERN GILA COUNTY WHERE SPOTTERS/RAWS DATA REPORTED .30 TO .45 INCH UP TO 6 AM. SIGNIFICANT DIFFLUENCE WAS ALSO INDICATED ACROSS EASTERN AZ EARLIER TODAY. UPDATES ISSUED BY 8 AM TO COVER 88D TRENDS. WILL CONTINUE TO EXPECT STRONGEST LIFT AND LOWEST STABILITY INDICES AFTER 18Z FRIDAY...AND THAT FITS NICELY WITH OUR CURRENT FCSTS. ALTHOUGH LATEST NAM GIVES PHX A 24 HR PRECIP AMOUNT OF .38 INCH WE WILL STILL EXPECT GENERALLY LIGHTER AMOUNTS ACROSS ZONE 23. HOWEVER WE COULD SEE MUCH MORE...ACROSS ZONE 24...PER HPC OUTPUT. OUR WESTERN ZONES WILL STAY MUCH DIRER...WITH SOME PATCHY BLWG DUST TODAY. IN FACT ONE SHARP-EYED SPOTTER CALLED IN A REPORT OF BLOWING DUST NEAR A FARM FIELD WEST OF TONOPAH. MODEL TRENDS CONTINUE TO BE VERY CONSISTENT IN KEEPING THE CLOSED LOW OVER NRN MEX INTO FRIDAY NIGHT. BY 12Z SAT LATEST GFS CALLS FOR THE CENTER OF CIRCULATION TO LIFT OUT TO NEAR ABQ...WITH CSDRBL RH THROUGH A DEEP LAYER EVEN WEST OF PHX. UPPER RIDGE AND WARMER TEMPS WILL ALSO SPREAD ACROSS ENTIRE CWA FOR FRIDAY AND SATURDAY. && .LONG TERM... SATURDAY NIGHT THROUGH WEDNESDAY... WITH SLOWER EXIT OF THE SYSTEM AND POTENTIAL FOR MORE MOISTURE... ADDED SOME SLIGHT CHANCE POPS IN EASTERN PORTIONS OF THE FORECAST AREA SATURDAY NIGHT. THIS IS FOLLOWED BY RIDGE BUILDING FOR A QUICK WARMUP. IN THE LATTER PART OF THE EXTENDED...GFS AND ECWMF ARE SHOWING ANOTHER SYSTEM AFFECTING US. HOWEVER...IT LOOKS TO BE OF A DIFFERENT CHARACTER...MUCH LESS APT TO SLOW DOWN AND JOG SOUTHWARD. HOWEVER...THERE ARE SOME DIFFERENCES. THE GFS ENSEMBLE MEAN HAS A SIMILAR TRACK TO THE 12Z OPERATIONAL GFS...TAKING THE BULK OF THE SYSTEM JUST NORTH OF OUR AREA...BUT SHOWS LOWER HEIGHTS. THE ECMWF IS EVEN COOLER LOOKING THAN THE ENSEMBLE MEAN...AND A BIT SLOWER. THUS...UNDERCUT GFS-BASED TEMPERATURE GUIDANCE. TRAJECTORY OF THIS NEXT SYSTEM DOES NOT FAVOR MUCH IN THE WAY OF POPS...SO HELD OFF ON INTRODUCING ANY. IF ECMWF SOLUTION WINDS UP BEING CORRECT...THEN WE MIGHT NEED TO ADD SOME SLIGHT CHANCE POPS AT SOME POINT. ALSO...IF ECMWF SOLUTION PANS OUT...MIGHT NEED EVEN COOLER TEMPS. && .AVIATION... GENERALLY LGT SHOWERS WITH EMBEDDED -TSRA WILL CONTINUE TO DRIFT TOWARD THE NORTH TODAY. WINDS IN THE 6 TO 12 THSD LAYER PROGGED TO REMAIN 180/22 THIS AFTERNOON...WITH MUCH STRONGER SPEEDS ALOFT. SOME GUSTY WINDS TO 35KTS OR SO STILL POSSIBLE IN THE KPHX AREA LATE THIS AFTERNOON AND INTO TONIGHT. WITH ADDITIONAL MOISTURE THROUGH A DEEP LAYER...WE COULD EASILY SEE LOWER CIGS LESS THAN 6-7 THSD FT. SEE TAFS PHXTAFPHX...PHXTAFIWA...PHXTAFYUM...LAXTAFBLH AND LAXTAFIPL FOR MORE DETAILED INFORMATION. AVIATION DISCUSSION IS NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... EXPECT PERIODS OF WETTING RAINFALL OVER MUCH OF THE FORECAST AREA THURSDAY THROUGH SATURDAY...MAINLY OVER THE EASTERN ZONES...WITH THE HEAVIEST PRECIPITATION LIKELY OVER SOUTHERN GILA COUNTY AND THE RIM FRI AFTERNOON INTO SAT MORNING. DRY CONDITIONS RETURN TO THE WESTERN PORTION OF THE REGION BY SATURDAY AND THE REMAINDER OF THE FORECAST AREA BY SUNDAY. EARLY NEXT WEEK (MON NIGHT THROUGH TUE)...AN INTENSE LOW PRESSURE SYSTEM WILL SWING THROUGH THE GREAT BASIN AND NORTHERN AZ GENERATING STRONG GUSTY WEST WINDS REGION-WIDE. WINDY CONDITIONS WILL BE LIKELY...AND IF HUMIDITIES AND FUEL MOISTURES REMAIN LOW...A CRITICAL FIRE WEATHER DAY WILL BE POSSIBLE. ALL INTERESTED AGENCIES ARE ENCOURAGED TO MONITOR THE LATEST FIRE WEATHER FORECASTS AND DISCUSSIONS. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...NONE. CA...NONE. && $$ NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT WEATHER.GOV/PHOENIX 10 az AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LITTLE ROCK AR 1253 AM CDT FRI MAR 23 2007 .AVIATION... HIGH PRESSURE CONTINUES OVER THE SOUTHEAST UNITED STATES. THUNDERSTORMS ARE ONGOING IN OKLAHOMA WITH A SLOW EASTWARD PROGRESSION. EXPECT THUNDERSTORMS TO ONLY AFFECT NORTH ARKANSAS TOWARDS 12Z AND INTERMITTENTLY THROUGH 18Z. MVFR CONDITIONS ARE EXPECTED IN THE NORTH AND VFR ELSEWHERE. CEILINGS IN THE NORTH WILL DROP TO 2500 FT WITH VISIBILITIES DOWN TO 5SM. THE UPPER LEVEL DISTURBANCE TRIGGERING THE THUNDERSTORMS WILL MOVE NORTH OF THE AREA AROUND 18Z. DRY WEATHER IS THEN EXPECTED INTO SATURDAY. && .PREV DISCUSSION... /ISSUED 905 PM CDT THU MAR 22 2007/ UPDATE... SHORTWAVE EJECTING OUT OF THE SOUTHWEST CONUS UPPER LOW CONTINUES TO RIDE A STALLED OUT BOUNDARY WHICH IS POSITIONED ALONG THE NORTHERN EDGE OF MID LEVEL RIDGE BUILDING INTO THE REGION FROM GULF. SHOWERS AND THUNDERSTORMS HAVE DEVELOPED OVER THE TEXAS PANHANDLE IN RESPONSE IN AN AREA OF STRONG LIFT. NEW RUC13 AND NAM 12 KEEP AREA OF PRECIPITATION ACROSS FAR NORTHWEST ARKANSAS AND SOUTHWEST MISSOURI OVERNIGHT. NAM12 AND WRF10 DO MOVE SOME PRECIPITATION ACROSS THE NORTHWEST PART OF THE LZK CWA AFTER 12Z BUT CONFIDENCE IS LOW THIS WILL DEVELOP AS OTHER SHORT RANGE MODELS INDICATE RIDGE BUILDING IN THE MID LEVELS THAT WILL KEEP PRECIPITATION OUT OF THE CWA. CURRENT DISTRIBUTION OF SMALL POPS OVER THE NORTHWEST PART OF THE CWA TONIGHT THROUGH PARTS OF FRIDAY LOOKS REASONABLE AND WILL BE LEFT IN PLACE. ONLY CHANGES TO ONGOING FORECAST WERE TO TWEAK SKY...DEW POINT AND RH GRIDS TO REFLECT CURRENT TRENDS. OVERNIGHT LOWS RAISED A TAD AS WELL. UPDATES OUT SHORTLY. PREV DISCUSSION... /ISSUED 629 PM CDT THU MAR 22 2007/ AVIATION... CLOUDS WILL CONTINUE TO MOVE IN FROM THE WEST WITH CEILINGS NEAR 7 THSD OR HIGHER. AREAS OF CEILINGS NEAR 35 HND WILL MOVE IN ARND 06Z. SCATTERED THUNDERSTORMS ARE POSSIBLE ACROSS THE NORTH AND WEST AFTER 08Z.(38) PREV DISCUSSION... /ISSUED 235 PM CDT THU MAR 22 2007/ SHORT TERM...TONIGHT THROUGH SUNDAY BLOCKING PATTERN STILL THE MAIN STORY IN THE SHORT TERM...WITH HIGH PRESSURE BUILDING OVER THE REGION FROM THE GULF COAST. FRONT TO NORTH WILL TRY TO PUSH INTO ARKANSAS LATER TONIGHT/FRIDAY...BUT WILL STALL DUE TO THE HIGH AND SOUTHWEST WINDS ALOFT. EVEN SO...PUT SMALL CHANCES FOR SHOWERS AND THUNDERSTORMS MAINLY IN AREAS NEAR THE ARKANSAS AND MISSOURI BORDER. FRONT WILL LIFT TO THE NORTH FRIDAY NIGHT/SATURDAY...WITH DRY AND WARM WEATHER TO START THE WEEKEND. LATE IN THE WEEKEND AND EARLY NEXT WEEK...LARGE STORM SYSTEM IN THE SOUTHWEST UNITED STATES WILL FINALLY ARRIVE...WITH HIGH PRESSURE SHIFTING SLOWLY TO THE EAST. BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS IN THE FORECAST LATE SUNDAY INTO THE LONG TERM. TEMPERATURES WILL REMAIN ABOVE NORMAL THROUGH THE PERIOD. (46) LONG TERM...SUNDAY NIGHT THROUGH THURSDAY REMNANTS OF A WEAKENING UPPER LOW WILL BE CROSSING ARKANSAS AS A SHORT WAVE. IT WILL BE JUST EAST OF THE STATE BY MIDDAY TUESDAY SINCE A LONG WAVE TROF WILL BE TRAVERSING THE INTERMOUNTAIN WEST ON TUESDAY. BY WEDNESDAY AFTERNOON IT WILL BE OVER THE NORTHERN PLAINS AND WEAKENING. THE SURFACE PATTERN WILL KEEP A SOUTHEAST OR SOUTH COMPONENT TO OUR WINDS THAT WILL PUMP MOISTURE NORTHWARD INTO THE PATH OF THE UPPER SYSTEM. WARMTH AND INSTABILITY WILL CAUSE SCATTERED CONVECTION TO DEVELOP SUNDAY NIGHT OVER NORTHWESTER SECTIONS. THEN...IT WILL KEEP ON MOVING EAST DURING THE DAY MONDAY. CONVECTION WILL BE OVER THE EASTERN HALF OF THE FORECAST AREA MONDAY NIGHT AND MOSTLY OUT OF THE STATE TUESDAY AFTERNOON AS THE SHORT WAVE DRIVING IT GOES ON BY ALOFT. WILL KEEP THE FORECAST DRY FROM TUESDAY NIGHT ON THROUGH THE END OF THE LONG TERM. THE UPPER SUPPORT FOR THE NEXT SYSTEM WILL BE SO FAR NORTH THAT DECIDED TO WAIT UNTIL THIS TREND GETS PICKED UP IN OTHER RUNS. NO CHALLENGE TO THE ABOVE NORMAL TRENDS WILL BE MADE DURING THIS PERIOD. (32) && .PRELIMINARY POINT TEMPS/POPS... BATESVILLE AR 56 76 58 76 / 20 10 10 20 CAMDEN AR 58 79 61 78 / 10 10 10 20 HARRISON AR 55 75 58 73 / 20 10 10 40 HOT SPRINGS AR 58 78 59 76 / 10 10 10 40 LITTLE ROCK AR 58 78 60 77 / 10 10 10 20 MONTICELLO AR 58 80 60 80 / 10 10 10 20 MOUNT IDA AR 57 78 59 75 / 10 10 10 40 MOUNTAIN HOME AR 54 75 56 75 / 20 10 10 40 NEWPORT AR 57 76 58 77 / 20 10 10 20 PINE BLUFF AR 59 79 61 78 / 10 10 10 20 RUSSELLVILLE AR 56 77 59 75 / 10 10 10 40 SEARCY AR 58 77 59 77 / 10 10 10 20 STUTTGART AR 59 78 60 78 / 10 10 10 20 && .LZK WATCHES/WARNINGS/ADVISORIES...NONE. && $$ AVIATION...51 ar AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LITTLE ROCK AR 905 PM CDT THU MAR 22 2007 .UPDATE... SHORTWAVE EJECTING OUT OF THE SOUTHWEST CONUS UPPER LOW CONTINUES TO RIDE A STALLED OUT BOUNDARY WHICH IS POSITIONED ALONG THE NORTHERN EDGE OF MID LEVEL RIDGE BUILDING INTO THE REGION FROM GULF. SHOWERS AND THUNDERSTORMS HAVE DEVELOPED OVER THE TEXAS PANHANDLE IN RESPONSE IN AN AREA OF STRONG LIFT. NEW RUC13 AND NAM 12 KEEP AREA OF PRECIPITATION ACROSS FAR NORTHWEST ARKANSAS AND SOUTHWEST MISSOURI OVERNIGHT. NAM12 AND WRF10 DO MOVE SOME PRECIPITATION ACROSS THE NORTHWEST PART OF THE LZK CWA AFTER 12Z BUT CONFIDENCE IS LOW THIS WILL DEVELOP AS OTHER SHORT RANGE MODELS INDICATE RIDGE BUILDING IN THE MID LEVELS THAT WILL KEEP PRECIPITATION OUT OF THE CWA. CURRENT DISTRIBUTION OF SMALL POPS OVER THE NORTHWEST PART OF THE CWA TONIGHT THROUGH PARTS OF FRIDAY LOOKS REASONABLE AND WILL BE LEFT IN PLACE. ONLY CHANGES TO ONGOING FORECAST WERE TO TWEAK SKY...DEW POINT AND RH GRIDS TO REFLECT CURRENT TRENDS. OVERNIGHT LOWS RAISED A TAD AS WELL. UPDATES OUT SHORTLY. && .PREV DISCUSSION... /ISSUED 629 PM CDT THU MAR 22 2007/ AVIATION... CLOUDS WILL CONTINUE TO MOVE IN FROM THE WEST WITH CEILINGS NEAR 7 THSD OR HIGHER. AREAS OF CEILINGS NEAR 35 HND WILL MOVE IN ARND 06Z. SCATTERED THUNDERSTORMS ARE POSSIBLE ACROSS THE NORTH AND WEST AFTER 08Z.(38) PREV DISCUSSION... /ISSUED 235 PM CDT THU MAR 22 2007/ SHORT TERM...TONIGHT THROUGH SUNDAY BLOCKING PATTERN STILL THE MAIN STORY IN THE SHORT TERM...WITH HIGH PRESSURE BUILDING OVER THE REGION FROM THE GULF COAST. FRONT TO NORTH WILL TRY TO PUSH INTO ARKANSAS LATER TONIGHT/FRIDAY...BUT WILL STALL DUE TO THE HIGH AND SOUTHWEST WINDS ALOFT. EVEN SO...PUT SMALL CHANCES FOR SHOWERS AND THUNDERSTORMS MAINLY IN AREAS NEAR THE ARKANSAS AND MISSOURI BORDER. FRONT WILL LIFT TO THE NORTH FRIDAY NIGHT/SATURDAY...WITH DRY AND WARM WEATHER TO START THE WEEKEND. LATE IN THE WEEKEND AND EARLY NEXT WEEK...LARGE STORM SYSTEM IN THE SOUTHWEST UNITED STATES WILL FINALLY ARRIVE...WITH HIGH PRESSURE SHIFTING SLOWLY TO THE EAST. BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS IN THE FORECAST LATE SUNDAY INTO THE LONG TERM. TEMPERATURES WILL REMAIN ABOVE NORMAL THROUGH THE PERIOD. (46) LONG TERM...SUNDAY NIGHT THROUGH THURSDAY REMNANTS OF A WEAKENING UPPER LOW WILL BE CROSSING ARKANSAS AS A SHORT WAVE. IT WILL BE JUST EAST OF THE STATE BY MIDDAY TUESDAY SINCE A LONG WAVE TROF WILL BE TRAVERSING THE INTERMOUNTAIN WEST ON TUESDAY. BY WEDNESDAY AFTERNOON IT WILL BE OVER THE NORTHERN PLAINS AND WEAKENING. THE SURFACE PATTERN WILL KEEP A SOUTHEAST OR SOUTH COMPONENT TO OUR WINDS THAT WILL PUMP MOISTURE NORTHWARD INTO THE PATH OF THE UPPER SYSTEM. WARMTH AND INSTABILITY WILL CAUSE SCATTERED CONVECTION TO DEVELOP SUNDAY NIGHT OVER NORTHWESTER SECTIONS. THEN...IT WILL KEEP ON MOVING EAST DURING THE DAY MONDAY. CONVECTION WILL BE OVER THE EASTERN HALF OF THE FORECAST AREA MONDAY NIGHT AND MOSTLY OUT OF THE STATE TUESDAY AFTERNOON AS THE SHORT WAVE DRIVING IT GOES ON BY ALOFT. WILL KEEP THE FORECAST DRY FROM TUESDAY NIGHT ON THROUGH THE END OF THE LONG TERM. THE UPPER SUPPORT FOR THE NEXT SYSTEM WILL BE SO FAR NORTH THAT DECIDED TO WAIT UNTIL THIS TREND GETS PICKED UP IN OTHER RUNS. NO CHALLENGE TO THE ABOVE NORMAL TRENDS WILL BE MADE DURING THIS PERIOD. (32) && .PRELIMINARY POINT TEMPS/POPS... BATESVILLE AR 59 76 56 76 / 10 20 20 10 CAMDEN AR 60 80 58 79 / 10 10 10 10 HARRISON AR 59 75 55 75 / 30 30 20 10 HOT SPRINGS AR 60 78 58 78 / 10 10 10 10 LITTLE ROCK AR 60 78 58 78 / 10 10 10 10 MONTICELLO AR 59 80 58 80 / 10 10 10 10 MOUNT IDA AR 58 78 57 78 / 10 10 10 10 MOUNTAIN HOME AR 59 75 54 75 / 30 30 20 10 NEWPORT AR 59 77 57 76 / 10 20 20 10 PINE BLUFF AR 60 79 59 79 / 10 10 10 10 RUSSELLVILLE AR 59 77 56 77 / 20 20 10 10 SEARCY AR 60 78 58 77 / 10 10 10 10 STUTTGART AR 60 79 59 78 / 10 10 10 10 && .LZK WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...56 / LONG TERM...38 ar AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA 845 PM PDT THU MAR 22 2007 .UPDATE...A FEW PATCHES OF HIGH CLOUDS MOVING THRU...OTHERWISE SKIES ARE CLEAR. MID LEVEL CLOUDS WRAPPING AROUND THE NRN BAJA LOW ARE JUST EAST OF KERN CO. SOME OF THESE MID CLOUDS COULD MOVE ACROSS THE KERN DESERT FROM TIME TO TIME OVERNITE SO PTCLDY THERE LOOKS GOOD. TEMPS THIS EVE RUNNING 6-8 DEGS HIGHER THAN YESTERDAY AT THIS TIME...SO CONTINUED GOOD WARMING EXPECTED TOMORROW. CURRENT FCST ON TRACK AND NO UPDATE NEEDED THIS EVE. && .DISCUSSION...AS THE CLOSED UPPER LOW DRIFTS FURTHER OVER THE DESERT SOUTHWEST...THE WEATHER OVER CENTRAL CALIFORNIA CONTINUES TO SETTLE DOWN. WITH THE SUNSHINE...TEMPERATURES SAW ANOTHER WARMING TREND AS MANY VALLEY LOCATIONS WERE RUNNING 5 TO 10 DEG-F ABOVE THAT OF WEDNESDAY AFTERNOON. WITH THE OFFSHORE FLOW ALOFT SUPPORTING TODAY/S WARMING TEMP/S...WILL HAVE NO PROBLEM REACHING THE 70S. WHILE WRAP AROUND MOISTURE IS BEING OBSERVED OVER THE DESERT SOUTHWEST...ASSOCIATED WITH THE CLOSED UPPER LOW...AND TRACKING NORTHEAST. WHILE SOME CLOUDS SHOULD ADVANCE INTO THE DISTRICT LATE THIS AFTERNOON...RUC ANALYSIS AND VISIBLE SATELLITE IMAGERY IS SHOWING ONLY MINIMAL AMOUNTS REACHING THE AREA. THEREFORE...WILL MAINTAIN MOSTLY CLEAR CONDITIONS WITH NO POSSIBLE WEATHER. YET...THE KERN COUNTY DESERTS MAY BE CLOSER TO THE STORM THEN THE REST OF THE DISTRICT. THEREFORE...WILL MAINTAIN THE SLIGHT CHANCE POPS OVER THE DESERTS (TOKEN) JUST IN CASE THE MOISTURE IS ABLE TO MAKE IT THIS FAR NORTH. IN ADDITION...BECAUSE OF THE SLOW DRIFT OF THE UPPER LOW...STRONG WINDS WILL CONTINUE TO BE OBSERVED OVER THE DESERT AND HIGHER ELEVATIONS OF THE DISTRICT THROUGH THIS EVENING. AS THE UPPER LOW SLOWLY TRACKS EAST OVER THE NEXT SEVERAL DAYS...WILL SEE THE UPPER LEVEL RIDGE DOMINATE THE WEST THROUGH THE WEEKEND. DRY WEATHER WILL PREVAIL WITH A WARMING TREND IN TEMPERATURES THROUGH ABOUT SUNDAY. AROUND SUNDAY...SHORT RANGE MODELS BEGIN LOWERING HEIGHTS AND SWITCH TO A MORE ZONAL FLOW PATTERN BEFORE ALLOWING ANOTHER TROF TO APPROACH THE WEST COAST. LATEST TIMING STILL HAS THE NEXT TROF OVER THE WEST COAST AROUND LATE MONDAY INTO EARLY TUESDAY. ENSEMBLES SHOWING LITTLE PHASE UNCERTAINTY BUT IS SHOWING GOOD SPREAD ON THE AMPLITUDE AROUND 12Z TUESDAY. THEREFORE...WILL KEEP THE BETTER CHANCES OF MEASURABLE PRECIP NORTH OF KERN COUNTY DURING THE EVENT. IN ADDITION...DURING TROF PASSAGE...MEDIUM RANGE MODELS SHOW 500MB TEMP/S DROPPING TO AROUND MINUS 24-28 DEG-C. BEING THAT THIS MAY BE A COLD SYSTEM...WILL MAINTAIN LOW SNOW LEVELS DURING THE STORM. FURTHERMORE...WITH SUCH COLD AIR ALOFT OVER THE REGION AT THIS TIME OF THE YEAR...CONDITIONS MAY BECOME VERY UNSTABLE DURING THE STORM EVENT. LINGERING SHOWERS OVER THE MOUNTAIN TOWARD TUESDAY WILL GIVE WAY TO CLEARING BY WEDNESDAY AND THURSDAY. && .AVIATION...VFR CONDITIONS WILL PREVAIL OVER THE CENTRAL CALIFORNIA INTERIOR THROUGH 06Z SATURDAY. FOR SPECIFIC DETAILS...PLEASE REFER TO THE TAFS FOR KMCE...KFAT AND KBFL AND TWEB ROUTES 421 AND 423. && .AIR QUALITY ISSUES... NONE && .HNX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ BINGHAM/MOLINA/MV WEATHER.GOV/HANFORD ca AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA 232 PM PDT THU MAR 22 2007 .DISCUSSION...AS THE CLOSED UPPER LOW DRIFTS FURTHER OVER THE DESERT SOUTHWEST...THE WEATHER OVER CENTRAL CALIFORNIA CONTINUES TO SETTLE DOWN. WITH THE SUNSHINE...TEMPERATURES SAW ANOTHER WARMING TREND AS MANY VALLEY LOCATIONS WERE RUNNING 5 TO 10 DEG-F ABOVE THAT OF WEDNESDAY AFTERNOON. WITH THE OFFSHORE FLOW ALOFT SUPPORTING TODAY/S WARMING TEMP/S...WILL HAVE NO PROBLEM REACHING THE 70S. WHILE WRAP AROUND MOISTURE IS BEING OBSERVED OVER THE DESERT SOUTHWEST...ASSOCIATED WITH THE CLOSED UPPER LOW...AND TRACKING NORTHEAST. WHILE SOME CLOUDS SHOULD ADVANCE INTO THE DISTRICT LATE THIS AFTERNOON...RUC ANALYSIS AND VISIBLE SATELLITE IMAGERY IS SHOWING ONLY MINIMAL AMOUNTS REACHING THE AREA. THEREFORE...WILL MAINTAIN MOSTLY CLEAR CONDITIONS WITH NO POSSIBLE WEATHER. YET...THE KERN COUNTY DESERTS MAY BE CLOSER TO THE STORM THEN THE REST OF THE DISTRICT. THEREFORE...WILL MAINTAIN THE SLIGHT CHANCE POPS OVER THE DESERTS (TOKEN) JUST IN CASE THE MOISTURE IS ABLE TO MAKE IT THIS FAR NORTH. IN ADDITION...BECAUSE OF THE SLOW DRIFT OF THE UPPER LOW...STRONG WINDS WILL CONTINUE TO BE OBSERVED OVER THE DESERT AND HIGHER ELEVATIONS OF THE DISTRICT THROUGH THIS EVENING. AS THE UPPER LOW SLOWLY TRACKS EAST OVER THE NEXT SEVERAL DAYS...WILL SEE THE UPPER LEVEL RIDGE DOMINATE THE WEST THROUGH THE WEEKEND. DRY WEATHER WILL PREVAIL WITH A WARMING TREND IN TEMPERATURES THROUGH ABOUT SUNDAY. AROUND SUNDAY...SHORT RANGE MODELS BEGIN LOWERING HEIGHTS AND SWITCH TO A MORE ZONAL FLOW PATTERN BEFORE ALLOWING ANOTHER TROF TO APPROACH THE WEST COAST. LATEST TIMING STILL HAS THE NEXT TROF OVER THE WEST COAST AROUND LATE MONDAY INTO EARLY TUESDAY. ENSEMBLES SHOWING LITTLE PHASE UNCERTAINTY BUT IS SHOWING GOOD SPREAD ON THE AMPLITUDE AROUND 12Z TUESDAY. THEREFORE...WILL KEEP THE BETTER CHANCES OF MEASURABLE PRECIP NORTH OF KERN COUNTY DURING THE EVENT. IN ADDITION...DURING TROF PASSAGE...MEDIUM RANGE MODELS SHOW 500MB TEMP/S DROPPING TO AROUND MINUS 24-28 DEG-C. BEING THAT THIS MAY BE A COLD SYSTEM...WILL MAINTAIN LOW SNOW LEVELS DURING THE STORM. FURTHERMORE...WITH SUCH COLD AIR ALOFT OVER THE REGION AT THIS TIME OF THE YEAR...CONDITIONS MAY BECOME VERY UNSTABLE DURING THE STORM EVENT. LINGERING SHOWERS OVER THE MOUNTAIN TOWARD TUESDAY WILL GIVE WAY TO CLEARING BY WEDNESDAY AND THURSDAY. && .AVIATION...GUSTY OFFSHORE WINDS WILL CONTINUE OVER KERN COUNTY DESERTS THROUGH EARLY EVENING THURSDAY...DIMINISHING THEREAFTER. OTHERWISE...VFR CONDITIONS WILL PREVAIL OVER THE CENTRAL CALIFORNIA INTERIOR THROUGH 00Z SATURDAY. FOR SPECIFIC DETAILS...PLEASE REFER TO THE TAFS FOR KMCE...KFAT AND KBFL AND TWEB ROUTES 421 AND 423. && .AIR QUALITY ISSUES...NONE. && .HNX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC:MOLINA AVIATION:MV WEATHER.GOV/HANFORD ca AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA 916 AM PDT THU MAR 22 2007 .DISCUSSION...CLOSED UPPER LOW CONTINUES TO SWINGS EASTWARD THIS MORNING AROUND BAJA CALIFORNIA...WITH CHANNELED FLOW OVER THE DISTRICT. AT THE 250MB LEVEL...RUC ANALYSIS HAS A +100KT JET MAX EXITING THE AREA WITH A GOOD DOWNWARD TRANSFER OF WINDS THIS MORNING. WHILE WINDS OVER THE MOUNTAINS AND DESERTS WERE DIMINISHING THIS MID MORNING...WINDS EARLIER WERE ABLE TO REACH 30 TO 40 MPH. AS THE JET MOVES FURTHER AWAY...WILL SEE MOUNTAIN WINDS DECREASE FURTHER AS A SHORT WAVE RIDGE SHIFTS INTO CALIFORNIA. FURTHERMORE...THE FLOW THIS MORNING HAS BEEN OFF-SHORE WHICH WILL SUPPORT THE EXPECTED WARM UP THIS AFTERNOON. OTHERWISE...AS THE CLOSED UPPER LOW MOVES FURTHER OUT...WILL SEE GENERAL CLEARING THROUGH THE END OF THE WEEK AND INTO THE WEEKEND WITH A CONTINUAL WARMING OF TEMPERATURES. NO UPDATES NEEDED. && .AVIATION...LOCAL MVFR CEILINGS AND VISIBILITIES WILL PERSIST ALONG THE EAST SIDE AND SOUTH END OF THE SAN JOAQUIN VALLEY AS WELL AS THE NORTH FACING SLOPES OF THE TEHACHAPI MOUNTAINS UNTIL 17Z. LOCALLY STRONG WINDS WILL ALSO BUFFET THE HIGHER ELEVATIONS OF THE SIERRA NEVADA AND THE INDIAN WELLS VALLEY THIS MORNING. OTHERWISE...VFR CONDITIONS WILL PREVAIL OVER THE CENTRAL CALIFORNIA INTERIOR THROUGH 12Z FRIDAY. FOR SPECIFIC DETAILS...PLEASE REFER TO THE TAFS FOR KMCE...KFAT AND KBFL AND TWEB ROUTES 421 AND 423. && .AIR QUALITY ISSUES...NONE. && .HNX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC:MOLINA AVIATION:MV WEATHER.GOV/HANFORD ca AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 437 AM MDT FRI MAR 23 2007 .SHORT TERM... (TODAY AND TONIGHT) ...ISOLD-SCT SHOWERS AND A FEW THUNDERSTORMS POSSIBLE TODAY... CURRENTLY...WATER VAPOR IMAGERY AND RUC MODEL UPPER AIR ANALYSES HAD A MATURING CLOSED LOW OVER THE CA BAJA WITH AN EXPANDED SYNOPTIC SCALE PRECIPITATION SHIELD IN THE NORTH-EAST QUADRANTS ACROSS AZ/WRN NM. SOME OF THE MIDDLE/HIGH LEVEL CLOUD SHIELD WAS MOVING INTO EXTREME SWRN CO. THERE WAS A ROGUE SMALL CLUSTER OF SHRA/TSRA OVER E CNTRL NM MOVING NWD...BUT IT CONTINUES TO DISSIPATE AS TO MOVES AWAY FROM ITS LOW LEVEL FORCING AND NO UPPER AIR SUPPORT. ISENTROPIC ASCENT DRIVEN ISOLD-SCT TSRA WAS ACROSS SRN NM JUST NORTH OF THE SURFACE WARM FRONT. THIS NEW MINI-MESOSCALE CONVECTIVE SYSTEM MAY FALL APART ONCE IT GETS INTO NERN NM EARLY THIS MORNING. BASICALLY...JUST SOME HIGH CLOUDS MOVING INTO OUR WRN CWFA/CONTDVD AND IN EXTREME SERN CO. TEMPERATURES ARE RELATIVELY MILD WITH 40S/LOWER 50S ACROSS SERN CO AND 20S/30S IN THE MOUNTAINS/ HIGH VALLEYS. TODAY...WE WILL BE WAITING FOR THE OLD CLOSED LOW TO EJECT LATER TONIGHT...SO NOT ANTICIPATING MUCH "SIGNIFICANT" WEATHER UNTIL LATER TONIGHT. THERE WILL BE ENOUGH MIDLEVEL MOISTURE AND INSTABILITY LATER THIS AFTERNOON TO TRIGGER SOME SHRA/TSRA OVER THE MOUNTAINS. ACROSS SERN CO...PRECIP MIGHT HAVE A TOUGH TIME REACHING THE GROUND...INITIALLY...GIVEN INVERTED-V THERMAL STRUCTURE SUPPORTING VIRGA AND LOCALLY GUSTY WINDS. SOME OF THE PRECIPITATION SHAFTS...IF THEY FORM...MAY MAKE IT TO THE GROUND BY MIDDLE TO LATE AFTERNOON ACROSS SERN CO. ANY SNOW POTENTIAL WOULD BE AT OR ABOVE 10K FT MSL LATER TODAY. CURRENT TEMPERATURES LOOK FAIRLY DOABLE AND BLENDED WITH LATEST MOS GUIDANCE. TONIGHT...06Z/23 WRF IS INTERESTING COMPARED TO THE 00Z/23 RUN. THE 00Z/23 RUN HAD THE TYPICAL DIURNAL CONVECTIVE PRECIPITATION DISSIPATING AFTER SUNSET WHILE WE WAIT FOR THE LOW AND ANY POTENTIAL SYNOPTIC SCALE ASCENT PRECIPITATION TO GENERATE TOWARDS SAT AM. WELL...NOW IT "BLOWS" UP SOME PRECIPITATION OVER THE SANGRE DE CRISTO MOUNTAINS AFTER MIDNIGHT...WHILE THE 00Z/23 DID NOT "BLOW UP" PRECIPITATION IN THIS AREA. ONE CONSISTENT PRECIPITATION ZONE DEVELOPING MAY BE ACROSS ERN NM/WRN TX/WRN OK INTO EXTREME SERN CO LATE TONIGHT. AS THE OLD CLOSED LOW LIFTS N-NEWD OUT OF AZ/WRN NM...RELATIVELY DEEP SLY FLOW BEGINS TO TRANSPORT MOISTURE PER H7 MOISTURE TRANSPORT VECTORS/MAG. THIS WILL HELP DESTABILIZE THE AIR MASS TO GENERATE NOCTURNAL THUNDERSTORMS ACROSS JUST S OF EXTREME SERN CO AND POSSIBLY MOVING INTO SERN CO AFTER MIDNIGHT. WRF SUGGESTING A LINEAR MESOSCALE CONVECTION SYSTEM JUST AHEAD OF THE CLOSED LOW IN THE AFOREMENTIONED AREA. MIGHT SEE SOME MODERATE TO HEAVY RAIN ACROSS EXTREME SERN CO AND SWD GIVEN GEORGE/S K-INDICES OF 35-40C AND H7-H5 SPECIFIC HUMIDITY AROUND 5 G/KG AND MORE IMPORTANTLY ANY PRECIPITATION TRAINING GIVEN A DEEP SLY FLOW. THE GREATER THREAT FOR MODERATE TO HEAVY RAIN WOULD BE S-SE OF EXTREME SERN CO...BUT IT MIGHT MOVE INTO BACA COUNTY IF CELLS CAN HOLD TOGETHER. INCREASED POPS ACROSS EXTREME SERN CO TO LIKELY FOR LATER TONIGHT. ANY SNOW POTENTIAL WOULD BE AT OR ABOVE 9K FT MSL. METZE .LONG TERM... (SATURDAY THROUGH THURSDAY) MODELS FINALLY COMING INTO BETTER CONSENSUS LIFTING CLOSED LOW FROM CENTRAL NM AND THE 4 CORNERS REGION THROUGH CENTRAL CO...AND INTO NE CO/SW NE BY 00Z SUNDAY. THIS BRINGS FCST AREA UNDER FAIRLY STRONG QG FORCING BY SAT MORNING...SPREADING NORTHWARD QUICKLY DURING THE LATE MORNING/EARLY AFTN. ATMOS BECOMES CONVECTIVELY UNSTABLE AS COLD CORE ALOFT MOVES OVER THE REGION BY AFTN...SO SHOULD SEE SOME EMBEDDED THUNDERSTORMS AS WELL. LOW LEVELS STILL LOOK FAIRLY WARM WITH THIS SYSTEM...WITH SNOW LEVELS STARTING AROUND 9KFT...DROPPING TO 8KFT BY LATE AFTN. BEST LIFT ACCORDING TO 00Z RUNS WILL AFFECT CEN CO UNDER DEFORMATION BAND AND MID LEVEL TROWAL. HOWEVER...WITH CONVECTIVE INSTABILITY...COULD SEE BOUTS OF HEAVY SNOW ACROSS JUST ABOUT ANY OF THE MTS. FOR THE SOUTHEAST PLAINS/ADJACENT INTERSTATE 25 CORRIDOR...SHOULD SEE SNOW SHOWERS RAMPING UP IN THE MID TO LATE MORNING AS H7 WINDS BRIEFLY BECOME EASTERLY AS H7 CLOSED LOW LIFTS NORTHWARD. FAR EASTERN PLAINS QUICKLY BECOME DRY SLOTTED BY MID/LATE MORNING THOUGH AS 90 KT UPPER JET CORE LIFTS NORTH INTO SE CO...SO COULD SEE A LULL IN THE SHOWERS LATE SAT MORNING...BEFORE THEY REDEVELOP ALONG THE FRONT DURING THE AFTN. NAM/GFS HAVE THE FRONT POSITIONED ALONG THE PALMER DIVIDE BY MID AFTN...WITH AROUND 800 J/KG OF CAPE ALONG/NORTH OF THE BOUNDARY. SOUTH OF A LINE FROM PUEBLO TO EADS...WESTERLY DOWNSLOPE FLOW QUICKLY MIXES OUT LOW LEVEL MOISTURE...WHICH SHOULD LIMIT AFTERNOON SHOWERS/THUNDERSTORMS POTENTIAL. WILL STILL HAVE TO MONITOR POTENTIAL FOR STRONG STORMS...MAINLY ACROSS KIOWA COUNTY...HOWEVER LATEST RUNS APPEAR TO KEEP BEST SVR POTENTIAL JUST TO THE EAST AND NORTHEAST. OF COURSE BIGGEST CHALLENGE WILL BE SNOW AMOUNTS ACROSS THE MOUNTAINS. NAM PAINTS A GENEROUS 4-8 INCHES OF SNOW FOR SAT ACROSS ALL BUT THE SRN SANGRES (IN PROXIMITY OF DRY SLOT)...WITH AN ADDITIONAL 3 INCHES OF SNOWFALL ACROSS THE CENTRAL MTS SAT NIGHT. GFS ON THE OTHER HAND HAS UP TO A FOOT OF SNOWFALL ACROSS THE CEN/SW MTS UNDER DEFORMATION BAND ON SAT...WITH UP TO AN ADDITIONAL 3 INCHES POSSIBLE ACROSS THE CENTRAL MTS SAT NIGHT. GFS MAY BE A LITTLE OVERDONE GIVEN CONVECTIVE NATURE...BUT WOULDNT BE SURPRISED TO SEE AROUND 4-8 INCHES OF SNOW FOR THE HIGHER MTN AREAS...WITH LOCALLY HEAVIER AMOUNTS POSSIBLE GIVEN CONVECTIVE POTENTIAL. ALL IN ALL...STILL LOOKS LIKE A POTENTIAL ADVISORY EVENT. DEPENDING ON WESTWARD EXTENT OF DRY SLOT...PIKES PEAK AND THE WET MTS COULD ALSO SEE LOW END ADVISORY NUMBERS...THOUGH BREVITY OF UPSLOPE MAY KEEP THEM JUST SHY. STILL SOME UNCERTAINTIES WITH THE POSITION OF DRY AIR WRAPPING AROUND UPPER LOW...WHICH COULD MAKE/BREAK THE SNOW AMOUNT FCST. SO WILL NOT HOIST ANY HIGHLIGHTS JUST YET. WILL LET DAY SHIFT GET A LOOK AT ANOTHER SET OF RUNS. SYSTEM PULLS EAST OF THE AREA BY SUN WITH SNOW SHOWERS QUICKLY WINDING DOWN. TEMPS REBOUND NICELY FOR THE EARLY PART OF NEXT WEEK...THEN GFS BRINGS ANOTHER CLOSED LOW ACROSS NRN CO/WY TUES NIGHT. THIS WILL BRING WARM AND WINDY CONDITIONS TO THE AREA ON TUES AHEAD OF THE SYSTEM...THEN INCREASING CHANCES FOR PRECIPITATION FOR THE MTS ALONG/WEST OF THE CONTINENTAL DIVIDE FOR TUES NIGHT/EARLY WED. THIS COULD POSE PROBLEMS FOR FIRE WEATHER CONCERNS GIVEN THE STRONG WINDS/LOW RH POTENTIAL ON FOR MID WEEK. NO CHANGES MADE TO GRIDS BEYOND TUES. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 17/31 co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSONVILLE FL 328 AM EDT FRI MAR 23 2007 .SYNOPSIS...SFC HIGH PRES RIDGE JUST OUR N WITH PREVAILING LOW LEVEL NE TO E FLOW OVER THE FORECAST AREA. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW THE MID-UPPER RIDGE FROM CENTRAL GOMEX NEWD INTO THE SE STATES. MOIST BOUNDARY LAYER...CLEAR SKIES AND CALM WINDS OVER SE GA SUPPORTING FOG DEVELOPMENT WITH ALMA OCCASIONAL REPORTING VIS BELOW 1SM. EXPECT MORE FOG DEVELOPMENT OVER ENTIRE CWA NEXT FEW HOURS WITH THE DENSE FOG MAINLY CONFINED IN INTERIOR SE GA. && .SHORT TERM...HIGH PRES SFC AND ALOFT WILL DOMINATE THE REGION WITH A 1026 MB SFC HIGH PINCHING OFF OVER SRN AL AND GA SAT-SUN. STRONG RIDGING ALOFT WILL ENSURE A DEFINITE WARMING TREND FOR MOST AREAS TODAY THROUGH SUNDAY. TODAY...PATCHY DENSE FOG EXPECTED THROUGH EARLY MORNING OVER SE GA WITH PATCHY FOG MOST OTHER AREAS. FOR MAX TEMPS PREFERRED A BLEND BUT MOSTLY LIKED THE MAV GUIDANCE AS MET VERIFYING A BIT TOO COOL. MID 80S ARE POSSIBLE INLAND SECTIONS. WEAKER PRES GRADIENT WILL PROVIDE MOSTLY ELY 10-15 MPH WINDS BUT STILL SOME GUSTINESS IN AFTERNOON BUT LOWER THAN PREVIOUS DAYS. TONIGHT...STRONGER HIGH PRES ALOFT WITH WEAKER BOUNDARY LAYER WINDS SPELLS FOR ANOTHER ROUND OF AREAS OF FOG AFTER MIDNIGHT LESS THAN 1SM AT TIMES BUT OTHERWISE MOSTLY CLEAR SKIES. LOWS MOSTLY IN THE MID 50S. SAT...MORNING FOG DISSIPATES GIVING WAY TO PARTLY TO MOSTLY SUNNY SKIES AND WARM TEMPS WITH MID 80S INLAND...UPPER 70S NEAR THE COAST. SAT NIGHT...MOSTLY CLEAR SKIES AND PATCHY TO AREAS OF FOG EXPECTED. LOWS CONTINUE TO BE MOSTLY MID 50S. SUNDAY...SFC HIGH PRES CONTINUES WITH WARM TEMPS FROM MID 80S TO UPPER 70S AGAIN. WILL BE SEEING A BACK-DOOR COLD FRONT SLIDE DOWN THE E COAST THROUGH CAROLINAS LATE IN THE DAY. .LONG TERM...SUN NIGHT-THU. MODEL GUIDANCE FASTER THAN YESTERDAY`S RUN SHOWING BACK-DOOR FRONT MOVING INTO THE FORECAST AREA. NAM AND GFS SHOWING FRONT MOVING INTO SE GA BETWEEN 06Z-12Z MON WITH POSSIBLE LIGHT SHOWERS ACCOMPANYING THE FRONT. FRONT PUSHES THROUGH ALL THE CWA WITH TEMPS A BIT COOLER ON NE FLOW THANKS TO 1033 MB HIGH OFF THE MID ATLC. PRES GRADIENT WILL HAVE INCREASED MON WITH BREEZY CONDS DEVELOPING OVER ERN ZONES. HAVE MOVED UP POPS TO MON AT 20% FOR PORTIONS OF SE GA AND NE FL AS ASSOCD MOISTURE WITH FRONT PUSHES THROUGH. SFC HIGH PRES RIDGE BUILDS SWD TUE-THU WITH NO MENTION OF POPS WITH SLIGHTLY WARMER TEMPS ANTICIPATED. && .AVIATION...WILL SEE TEMPO MVFR AT ALL TAF SITES BETWEEN 09Z AND 12Z DUE MAINLY TO VSBY. OTHERWISE VFR. EAST WINDS INCREASE BY EARLY THIS AFTERNOON WITH GUSTS TO NEAR 20 KNOTS AFTER 16Z. && .MARINE...WITH RIDGE BUILDING IN...WINDS AND EASTERLY SWELLS WILL SUBSIDE TODAY AND THROUGH THE WEEKEND. WILL KEEP THE ADVISORY FOR SEAS GOING THROUGH SATURDAY AND DROP ON SUNDAY. A STRONG BACK DOOR FRONT MOVES DOWN THE COAST MONDAY AND WILL PROBABLY SEE SCA CONDITIONS RETURN AGAIN. && .FIRE WX...BRIEF DURATIONS OF RH`S AOB 35% POSSIBLE TODAY AND SAT AFTN ACROSS THE SUWANNEE RIVER VALLEY IN NE FL. OTHERWISE NO MAJOR CONCERNS THROUGH THE WEEKEND. WINDS ARE EXPECTED TO INCREASE TO 15 MPH INLAND AND 15 TO 20 MPH ALONG THE COAST MONDAY WHEN A BACK DOOR FRONT SWEEPS THROUGH THE AREA. && .PRELIMINARY POINT TEMPS/POPS... AMG 83 54 85 53 / 10 10 10 10 SSI 74 58 76 57 / 0 0 0 10 JAX 79 55 81 55 / 10 10 10 10 SGJ 74 59 75 60 / 10 10 0 10 GNV 83 53 83 55 / 10 10 0 10 OCF 83 55 83 55 / 10 10 0 10 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...NONE. GA...NONE. AM...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 3 PM EDT SATURDAY FOR ALTAMAHA SOUND GA TO FERNANDINA BEACH FL 20 NM TO 60 NM OFFSHORE-FERNANDINA BEACH TO ST AUGUSTINE FL 20 NM TO 60 NM OFFSHORE-ST AUGUSTINE TO FLAGLER BEACH FL 20 NM TO 60 NM OFFSHORE. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 8 PM EDT THIS EVENING FOR FERNANDINA BEACH TO ST AUGUSTINE FL OUT 20 NM- ST AUGUSTINE TO FLAGLER BEACH FL OUT 20 NM. && $$ SHASHY/PETERSON fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 130 PM CDT THU MAR 22 2007 .DISCUSSION FOR ZONES/GRIDS... 11AM...SKIES ARE CLEARING OVER MUCH OF FCST AREA AT LATE MRNG AS WINDS TURN NW AND TEMPS STEADY OUT. COLD ADVECTION ON NW WINDS WILL HOLD TEMPS WITHIN FEW DEG OF CURRENT LEVELS THROUGH THE AFTERNOON. HIGH PERS OVER NW IOWA SHOULD DRIFT ACROSS TONIGHT FOR SOMEHWAT COOLER TEMPS. RETURN MOISTURE AND CLOUDS ETC LKLY TO BEGIN LATER TONIGHT AND CONTINUE FRIDAY. CHARACTER OF THAT RETURN REMAINS TO BE SEEN AND WILL TRIM/DELAY RETURN A LITTLE IN UPDATED GRIDS. FAIRLY MARKED DIFFERENCES IN GFS AND NAM IN GROWING AMPLITUDE OF EJECTING WESTERN TROUGH NEXT 48HRS IS ONE SOURCE OF UNCERTAINTY. KL PREVIOUS DISCUSSION 330 AM CDT MAIN FORECAST CONCERN WILL BE ON CONVECTION MAINLY THIS MORNING...AND THEN CONTINUED CHANCES OF SHOWERS/THUNDERSTORMS FROM LATER TONIGHT THROUGH THE WEEKEND AND THE POTENTIAL FOR HEAVY RAINFALL AND CONTINUED FLOOD POTENTIAL. APOLOGIES FOR AN ABBREVIATED DISCUSSION DUE TO INCREASING CONVECTION ACROSS THE AREA THIS MORNING. SURFACE COLD FRONT IS NOW APPROACHING THE MISSISSIPPI RIVER WITH SPC RUC MESOSCALE ANALYSIS GRAPHICS INDICATING BETWEEN 500-1000 J/KG OF ELEVATED INSTABILITY IN CLOSE PROXIMITY TO THE SFC FRONT WHERE LOW LEVEL DEW POINT POOLING IS OCCURRING. EXPECTING INCREASE COVERAGE OF SHOWERS AND THUNDERSTORMS THIS MORNING WITH APPROACH OF THIS INSTABILITY AXIS AND ALSO INCREASING UPPER SUPPORT TOWARD 12Z AS NORTHERN STREAM VORT MAX PUSHES INTO THE NORTHERN GREAT LAKES AND AS UPPER JET STREAK CUTS THROUGH THE BASE OF THIS TROUGH INTO THE MID MISSISSIPPI RIVER VALLEY. FRONT WILL RAPIDLY MOVE ACROSS THE CWA TODAY...AND BY LATE MORNING ANY REMAINING SHOWERS/THUNDERSTORMS SHOULD BE CONFINED TO FAR SOUTHEASTERN SECTIONS OF THE CWA. GIVEN INSTABILITY AND INCREASING SHEAR NEAR THE FRONTAL BOUNDARY...WILL HAVE TO MONITOR FOR WIND/HAIL THREAT FOR FIRST FEW HOURS THIS MORNING. FAST MOVING NATURE OF STORMS SHOULD KEEP RAINFALL TOTALS UNDER CONTROL BUT COMBINATION OF ADDITIONAL RAINFALL AND RAIN OF PREVIOUS AFTERNOON MAY LEAD TO SOME MINOR FLOODING PROBLEMS THIS MORNING. HAVE MADE SOME REVISIONS TO THE FORECAST TONIGHT INTO FRIDAY...WITH LATEST MODEL RUNS COMING INTO BETTER AGREEMENT IN A MORE NORTHERLY POSITION OF SFC FRONTAL BOUNDARY AND BETTER CHANCES OF PERIODIC EPISODES OF SHOWERS/THUNDERSTORMS...ESPECIALLY SOUTH OF INTERSTATE 80 WHERE ISENTROPIC LIFT WILL BE MORE PRONOUNCED. ALREADY HIGH RIVER LEVELS WILL HAVE TO BE MONITOR FOR ADDITIONAL FLOODING GIVEN. WILL REINTRODUCE LIKELY POPS FOR TSRA ACROSS SOUTHERN AREAS LATE TONIGHT...AND LIKELY SHOWERS AS FAR NORTH AS INTERSTATE 88...TAPERING TO CHANCE POPS FAR NORTH. ALSO INCREASED POPS FOR FRIDAY WITH BOUNDARY STILL IN THE AREA. LITTLE CHANGES MADE TO THE REMAINDER OF THE FORECAST. MARSILI && .AVIATION... THE COLD FRONT HAS MOVED SOUTH OF THE TAF FORECAST AREA OF NORTHEAST ILLINOIS AND NORTHWEST INDIANA. THE WIND PROFILER DATA SHOWS A WEST WIND IN ILLINOIS AT 700 MB AND AT 850 MB. WITH THIS WIND PATTERN ALOFT THE FRONT WILL PROBABLY STALL OVER CENTRAL ILLINOIS. A HIGH WILL MOVE ACROSS THE NORTH CENTRAL PART OF THE STATE THIS EVENING. THE WIND WILL BECOME SOUTHERLY AND THE FRONT WILL MOVE NORTH INTO NORTH CENTRAL ILLINOIS AND NORTHWEST INDIANA LATE TONIGHT. WE WILL ADD THUNDERSTORMS TOWARD FROM 11 TO 12 UTC. THIS IS THE TIME OF MAXIMUM CONVERGENCE AS THE FRONT MOVES THROUGH. WE WILL HAVE LIGHT RAIN THROUGH THE MORNING ACROSS THE FORECAST AREA. WE EXPECT A SOUTHEAST WIND AFTER MIDNIGHT TONIGHT. WE USED THE NAM AND A LOCALLY RUN WRF MODEL. && .LOT WATCHES/WARNINGS/ADVISORIES... .IL...NONE. .IN...NONE. .LM...NONE. && $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 650 AM CDT THU MAR 22 2007 .DISCUSSION FOR AFTERNOON ZONES/GRIDS... 330 AM CDT MAIN FORECAST CONCERN WILL BE ON CONVECTION MAINLY THIS MORNING...AND THEN CONTINUED CHANCES OF SHOWERS/THUNDERSTORMS FROM LATER TONIGHT THROUGH THE WEEKEND AND THE POTENTIAL FOR HEAVY RAINFALL AND CONTINUED FLOOD POTENTIAL. APOLOGIES FOR AN ABBREVIATED DISCUSSION DUE TO INCREASING CONVECTION ACROSS THE AREA THIS MORNING. SURFACE COLD FRONT IS NOW APPROACHING THE MISSISSIPPI RIVER WITH SPC RUC MESOSCALE ANALYSIS GRAPHICS INDICATING BETWEEN 500-1000 J/KG OF ELEVATED INSTABILITY IN CLOSE PROXIMITY TO THE SFC FRONT WHERE LOW LEVEL DEW POINT POOLING IS OCCURRING. EXPECTING INCREASE COVERAGE OF SHOWERS AND THUNDERSTORMS THIS MORNING WITH APPROACH OF THIS INSTABILITY AXIS AND ALSO INCREASING UPPER SUPPORT TOWARD 12Z AS NORTHERN STREAM VORT MAX PUSHES INTO THE NORTHERN GREAT LAKES AND AS UPPER JET STREAK CUTS THROUGH THE BASE OF THIS TROUGH INTO THE MID MISSISSIPPI RIVER VALLEY. FRONT WILL RAPIDLY MOVE ACROSS THE CWA TODAY...AND BY LATE MORNING ANY REMAINING SHOWERS/THUNDERSTORMS SHOULD BE CONFINED TO FAR SOUTHEASTERN SECTIONS OF THE CWA. GIVEN INSTABILITY AND INCREASING SHEAR NEAR THE FRONTAL BOUNDARY...WILL HAVE TO MONITOR FOR WIND/HAIL THREAT FOR FIRST FEW HOURS THIS MORNING. FAST MOVING NATURE OF STORMS SHOULD KEEP RAINFALL TOTALS UNDER CONTROL BUT COMBINATION OF ADDITIONAL RAINFALL AND RAIN OF PREVIOUS AFTERNOON MAY LEAD TO SOME MINOR FLOODING PROBLEMS THIS MORNING. HAVE MADE SOME REVISIONS TO THE FORECAST TONIGHT INTO FRIDAY...WITH LATEST MODEL RUNS COMING INTO BETTER AGREEMENT IN A MORE NORTHERLY POSITION OF SFC FRONTAL BOUNDARY AND BETTER CHANCES OF PERIODIC EPISODES OF SHOWERS/THUNDERSTORMS...ESPECIALLY SOUTH OF INTERSTATE 80 WHERE ISENTROPIC LIFT WILL BE MORE PRONOUNCED. ALREADY HIGH RIVER LEVELS WILL HAVE TO BE MONITOR FOR ADDITIONAL FLOODING GIVEN. WILL REINTRODUCE LIKELY POPS FOR TSRA ACROSS SOUTHERN AREAS LATE TONIGHT...AND LIKELY SHOWERS AS FAR NORTH AS INTERSTATE 88...TAPERING TO CHANCE POPS FAR NORTH. ALSO INCREASED POPS FOR FRIDAY WITH BOUNDARY STILL IN THE AREA. LITTLE CHANGES MADE TO THE REMAINDER OF THE FORECAST. MARSILI && .AVIATION... 650 AM CDT MID LVL S/WV TROF CONTINUES TO PLOW INTO WRN GRTLKS REGION THIS MORNING...COLD FRONT PUSHING THRU FCST AREA AT 12Z. BAND OF ELEVATED CONVECTION ASSOCIATED WITH 55 KT LLJ NOW PUSHING OFF TO THE EAST OF FCST AREA AS 950-850 HPA FLOW BECOMING A BIT MORE WESTERLY WITH APPROACH OF TROF...THOUGH A FEW ISOLATED CELLS STILL DVLPG GENERALLY ALONG/SOUTH OF A KVYS...KLOT...KGYY LINE ASSOCIATED WITH ELEVATED INSTABILITY PLUME/LLJ AXIS. EXPECT THESE TO REMAIN SOUTH OF TERMINALS WITH EXCEPTION OF KGYY FIRST COUPLE OF HOURS OF TAF PERIOD EARLY THIS MORNING. OTHERWISE...COLD FROPA HAS OCCURRED AT KRFD AND WILL BE INTO CHI AREA TERMINALS NEXT 1-2 HRS. PATCHY MVFR CIGS IN 1500-2000 FT RANGE IMMEDIATELY BEHIND FRONT...THOUGH STRONG LLVL DRY ADVECTION DVLPG POST FRONTAL SHOULD CLR THIS OUT BY LATE MORNING. STRONG ISALLOBARIC GRADIENT WITH PRESSURE RISES BEHIND FRONT...SO WITH WSFT TO NW XPCT TO CONTINUE TO SEE GUSTS INTO THE LOW/MID 20 KT RANGE THIS MORNING. SFC HIGH PRESSURE BUILDS IN RAPIDLY THIS AFTN/THIS EVE ALLOWING WINDS TO DECREASE QUICKLY...GOING VRBL THIS EVE. WILL LIKELY SEE A BIT OF A LAKE BREEZE TOWARD EVE ALONG IL/IND LAKE MICH SHORE AS GRADIENT RELAXES. NEXT S/WV PROPAGATES ACROSS UPPER MIDWEST TONIGHT...WITH ANOTHER ROUND OF WAA/UPGLIDE DVLPG ACROSS BAROCLINIC FRONTAL ZONE TO SOUTH OF FCST AREA OVRNGT. 06Z NAM/GFS RUNS BOTH FOCUS PCPN SOUTH OF TERMINALS WITH VFR CIG DVLPG. COULD SEE PCPN FARTHER NORTH INTO TERMINAL SITES AFTER 06Z TONIGHT...THOUGH CONFIDENCE THAT FAR NORTH IS LOW ATTM. RATZER && .LOT WATCHES/WARNINGS/ADVISORIES... .IL...NONE. .IN...NONE. .LM...SMALL CRAFT ADVISORY ILLINOIS NEARSHORE THROUGH 18Z THURS. SMALL CRAFT ADVISORY INDIANA NEARSHORE 18Z WED-18Z THURS. && $$ il AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE GOODLAND KS 856 PM MDT FRI MAR 23 2007 .DISCUSSION...JUST SENT AN UPDATE. CHANGES WERE MINOR. INCREASED POPS SLIGHTLY OVER MOST OF THE FORECAST AREA WHICH MATCHES WITH CURRENT AREA OF THUNDERSTORMS AND THE MODEL DEPICTION OF THIS AREA EXPANDING TO THE NORTH AND EAST THROUGH THE NIGHT. ALSO ADJUSTED PRECIPITATION AMOUNTS. LOWERED AMOUNTS IN THE EAST WHICH PRECIPITATION HAS YET TO START...AND THEN RAISED THEM AFTER MIDNIGHT. ALSO ADJUSTED SKY COVER...TEMPERATURE/DEWPOINT...AND WIND GRIDS THROUGH THE REST OF THE NIGHT BASED ON CURRENT TRENDS/LATEST RUC. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ BULLER ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 924 AM MDT FRI MAR 23 2007 .UPDATE...ZONES HAVE BEEN UPDATED TO EXTEND THE DENSE FOG ADVISORY FOR THE KANSAS AND SOUTHWEST NEBRASKA COUNTIES UNTIL 11 AM MDT/ NOON CDT. LATEST RUC SOUNDINGS SHOW INVERSION TO TAKE A LITTLE LONGER TO BREAK WITH GOOD AMOUNT OF LOW LEVEL MOISTURE. SURFACE OBSERVATIONS STILL AT A QUARTER OF A MILE REPORTED AT SOME LOCATIONS INCLUDING GOODLAND...COLBY AND MCCOOK. EXPECT FOG TO LIFT BY LATER IN THE MORNING. REST OF FORECAST STILL ON TRACK. WILL BE WATCHING HIGH TEMPERATURES TODAY CLOSELY WHICH MAY BE DEPENDENT ON AMOUNT OF CLOUDINESS THROUGHOUT THE DAY. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...DENSE FOG ADVISORY UNTIL 11 AM MDT /NOON CDT/ THIS MORNING FOR KSZ001>004-013>016-027>029-041-042. NE...DENSE FOG ADVISORY UNTIL 11 AM MDT /NOON CDT/ THIS MORNING FOR NEZ079>081. CO...NONE. && $$ LAMMERS ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WICHITA KS 1038 AM CDT THU MAR 22 2007 .UPDATE... SURFACE FRONT HAD BECOME QUASI-STATIONARY GENERALLY JUST SOUTH OF HIGHWAY 50 AT MID-MORNING...WITH THE LATEST NAM AND RUC SUGGESTING A SLIGHT NORTHWARD MOVE INTO THE AFTERNOON. THIS IS SLIGHTLY NORTH OF EARLY MORNING GRID PACKAGE...SO HAVE REFLECTED THE CHANGES IN THE LATEST GRID/FORECAST UPDATE. AS FOR CONVECTIVE CHANCES FOR THIS AFTERNOON...A LOT WILL DEPEND ON DIURNAL HEATING (IE. CLOUD TRENDS) ALONG AND SOUTH OF SURFACE FRONTAL BOUNDARY. DESPITE SOME HOLES INTO MIDDAY...HIGHER LEVEL CLOUDS LOOK TO ENCROACH SOUTH CENTRAL KANSAS DURING THE EARLY AFTERNOON. CONVERGENCE ALONG THE BOUNDARY LOOKS SUFFICIENT TO FOCUS CONVECTION WITH POTENTIAL ML CAPES OF AROUND 1800 J/KG LATER THIS AFTERNOON. SO LITTLE CHANGE TO THE GOING POP FORECAST AND FLOOD WATCH HEADLINE. BETTER CHANCES FOR ELEVATED CONVECTION APPEAR TO BE IN THE OFFING LATE THIS EVENING OR OVERNIGHT...ALONG AND NORTH OF SURFACE FRONT. KED && .PREV DISCUSSION... /ISSUED 328 AM CDT THU MAR 22 2007/ DISCUSSION... FORECAST CONCERNS TODAY ARE TSRA CHANCES FOR TODAY THROUGH THE WEEKEND AND ALSO TEMPS. TODAY: WAVY FRONTAL BOUNDARY MAKING SLOW PROGRESS INTO THE SOUTHERN KS AT THIS TIME. SOME WIDELY SCATTERED TSRA FINALLY HAVE DEVELOPED ALONG THE BOUNDARY AS LOW LEVEL JET INCREASES OVER THE TOP OF THE FRONT HELPING TO GET ELEVATED STORMS GOING. QUESTION TODAY IS HOW FAR SOUTH /IF AT ALL/ THIS FRONT WILL MAKE IT BEFORE STALLING OUT LATER THIS MORNING. SOME PRESSURE RISES STILL NOTED BEHIND THE BOUNDARY SO PREFER THE NAM-WRF FOR FRONTAL PLACEMENT GENERALLY ALONG AN EMP-HUT LINE BEFORE IT STALL. WHERE THE BOUNDARY WILL ULTIMATELY STALL OUT IS THE BIG PROBLEM TODAY AS THIS BOUNDARY WILL PROVIDE THE FOCUS FOR CONVECTION AND POSSIBLE TRAINING ECHOES. EXPECT SOME CONVECTION TO BE ONGOING EARLY IN THE PERIOD...BUT MAIN TSRA CHANCE WILL BE THIS AFTERNOON AS A MID LEVEL IMPULSE IN THE SOUTHWEST FLOW AND INCREASING ISENTROPIC LIFT IN THE 305K LAYER WILL STEEPEN LAPSE RATES ENOUGH FOR A MORE WIDESPREAD CONVECTION CHANCE. INSTABILITY IS MODEST WITH MUCAPE VALUES THIS AFTERNOON ONLY AROUND 1000 J/KG...BUT 0-6KM SHEAR VALUES STILL SUGGEST A POSSIBLE LARGE HAIL THREAT FOR AREAS WHERE SURFACE HEATING CAN BE MAXIMIZED. WITH SOME SURFACE BASED CONVECTION POSSIBLE SOUTH OF THE BOUNDARY OVER AREAS WITH SATURATED GROUNDS...WILL LEAVE THE FLOOD WATCH GOING FOR SOUTH CENTRAL AND SOUTHEAST KS BUT DAY SHIFT WILL PROBABLY HAVE TO BETTER DEFINE THIS ONCE BOUNDARY DECIDES TO STOP ITS SOUTHERN PROGRESS. WILL RAISE MAX TEMPS IN SOUTHERN KS AS BOUNDARY JUST TO THE NORTH OF THIS AREA WILL ALLOW TEMPS TO CLIMB INTO THE LOWER 70S. TONIGHT: BOUNDARY DRIFTS TO THE NORTH SOME AS THE NIGHT PROGRESSES...WITH SOME ISENTROPIC LIFT STILL LOCATED SOUTH OF THE BOUNDARY. SO EXPECT SOME CONVECTION IN SOUTHEAST KS EARLY BUT PROBABLY DIMINISHING OVERNIGHT. THIS LIFT WILL PROBABLY LEAD TO SOME TRANING STORMS IN AND NEAR THE BOUNDARY...SO FLOODING THREAT WILL DEFINATELY HAVE TO BE WATCHED. FRI-FRI NIGHT: NOT ALOT OF CONFIDENCE IN FRONTAL PLACEMENT AND POSSIBLE CONVECTION FOR FRI. MODELS ALSO DIFFER ON MID LEVEL IMPULSES EXPECTED TO MOVE ACROSS THE AREA IN THE SOUTHWEST FLOW. WITH THE BOUNDARY STILL EXPECTED TO BE IN THE AREA WILL LEAVE CHANCE POPS IN MOST LOCATIONS AS ANY WEAK IMPULSE COULD LEAD TO DEVELOPMENT...BUT DO NOT EXPECT TSRA CHANCE TO BE WIDESPREAD. BETTER DEVELOPMENT LOOKS TO BE FRI NIGHT AS ISENTROPIC LIFT AGAIN INCREASES ACROSS THE AREA. WILL STILL ONLY GO CHANCE POPS FOR NOW AS PLACEMENT OF THE BOUNDARY IN LATER RUNS WILL BETTER DEFINE HIGHEST POP AREAS. SAT-SUN: CONFIDENCE REMAINS LOW DURING THIS TIME FRAME AS BOUNDARY REMAINS SOMEWHAT STATIONARY ON SAT FOR BEGINNING TO LIFT TO THE NORTH AGAIN AS A WARM FRONT ON SUN AND MAIN SHORTWAVE REMAINS SOUTHWEST OF THE AREA UNTIL SUN EVENING. WITH LOTS OF LOW LEVEL MOISTURE AROUND HEAVY RAINFALL THREAT WILL ALSO CONTINUE. WILL HAVE TO KEEP AN EYE ON SEVERE THREAT ON SAT AS SHEAR VALUES LOOK FAVORABLE BUT INSTABILITY LOOKS MODEST. MONDAY-WEDNESDAY: PRECIP CHANCES LOOK TO COME TO AN END ON MONDAY AS MED RANGE MODELS FINALLY MOVE THE MAIN SHORTWAVE ACROSS THE AREA. LOOKS LIKE TUESDAY WILL BE A DAY TO DRY OUT WITH WEAK RIDGING IN THE MID LAYERS. A RATHER RIGOROUS SHORTWAVE MOVES INTO THE PLAINS ON WED FOR ANOTHER POSSIBLE ROUND OF CONVECTION. KETCHAM && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 74 59 72 58 / 50 60 40 40 HUTCHINSON 70 58 72 57 / 40 50 40 40 NEWTON 71 58 71 57 / 50 60 40 40 ELDORADO 73 59 72 58 / 60 60 40 40 WINFIELD-KWLD 73 60 73 59 / 60 60 40 40 RUSSELL 61 51 71 53 / 20 30 40 40 GREAT BEND 64 53 71 55 / 30 40 40 40 SALINA 63 52 69 54 / 30 50 40 40 MCPHERSON 67 56 71 56 / 40 50 40 40 COFFEYVILLE 76 61 73 59 / 60 60 40 30 CHANUTE 74 60 72 59 / 60 60 40 30 IOLA 73 59 72 58 / 60 60 40 30 PARSONS-KPPF 74 61 73 59 / 60 60 40 30 && .ICT WATCHES/WARNINGS/ADVISORIES... FLOOD WATCH THROUGH FRIDAY MORNING FOR KSZ069>072-083-092>096- 098>100. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TOPEKA KS 440 AM CDT THU MAR 22 2007 .DISCUSSION... THE UNSETTLED PATTERN CONTINUES. INTERESTING SET UP TODAY WITH SFC BNDRY TO THE SOUTH AND GOOD OVER-RUNNING PATTERN DEVELOPING. LATEST RUC SOUNDINGS SHOW GOOD ELEVATED LIFT DEVELOPING NORTH OF THE SFC BNDRY BY MIDDAY ALONG OR JUST SOUTH OF INTERSTATE 70. OPTIMUM ELEVATED LIFT WITH FAIRLY GOOD CHANCE FOR THUNDERSTORMS MOVES SLOWLY NORTH THROUGH THE AFTERNOON AND OVERNIGHT...REACHING THE NORTHERN BORDER AFTER MIDNIGHT. PATTERN SUPPORTIVE OF LOCALLY HEAVY RAINS WITH TRAINING OVER SAME AREAS. NO FLOOD WATCH ISSUED YET...BUT BEARS WATCHING IN 12Z RUN. PRECIPITABLE WATER VALUES EXCEEDINGLY HIGH FOR THIS TIME OF YEAR...RUNNING NEARLY 250% OF NORMAL! THIS HIGH WATER CONTENT CONTINUES INTO THE WEEKEND AND DOES NOT REALLY GET MODIFIED TO ANY GREAT EXTENT UNTIL UPPER SYSTEM FINALLY LIFTS THROUGH FROM THE SOUTHWEST STATES EARLY NEXT WEEK. UNTIL THEN, PERIODIC CHANCES FOR CONVECTION...SOME OF WHICH MAY BE STRONG TO SEVERE. SETUP FOR SEVERE TODAY IS MAXIMIZED ALONG AND NORTH OF THE WARMFRONT. CONSIDERABLE HIGH CLOUDINESS WILL LIMIT SOLAR INSOLATION TO FRONTAL AREA OTHERWISE TEMPERATURES WOULD BE WARMER AND THE THREAT FOR SEVERE HAIL WOULD BE EVEN GREATER. SHEAR SEEMS TO BE SUFFICIENT FOR LARGE HAIL LATER TODAY AS WELL. TEMPERATURES IN TURN A REAL CHALLENGE WITH CLOUDS HANGING TOUGH TO THE NORTH OF THE FRONT. HAVE FOLLOWED NAM CLOSELY WITH IT`S SFC TEMPERATURE FCST. THUS COULD RANGE FROM THE UPPER 40S NORTH TO THE LOWER 70S SOUTH. BY FRIDAY THE FRONT SHOULD RESIDE ALONG THE NORTHERN BORDER WAITING FOR AN UPPER WAVE TO EJECT OUT OF MEAN WESTERN TROF POSITION. THIS COULD TRIGGER ANOTHER ROUND OF CONVECTION FRIDAY NIGHT. BETTER CHANCE APPEARS SATURDAY NIGHT INTO SUNDAY NIGHT AS UPPER SYSTEM LIFTS NORTHEAST INTO THE PLAINS. LATER PERIODS OF THE FORECAST NOT CHANGED MUCH AS IS IMPOSSIBLE TO ADD MUCH DETAIL OR FIND REASONS TO MAKE CHANGES IN SUCH AN UNSETTLED PATTERN. && .TOP WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DODGE CITY KS 358 AM CDT THU MAR 22 2007 .DISCUSSION... DAYS 1-2... A NORTHERN STREAM SHORTWAVE TROUGH PASSED ACROSS THE NORTHERN PLAINS AND INTO THE GREAT LAKES OVERNIGHT. THIS HELPED PUSH A COLD FRONT THROUGH MOST OF SW KS. THE FRONT AS OF 3 AM STRETCHED FROM NORTH OF HUGOTON TO HUTCHINSON. SFC TEMPS WERE VERY BALMY SOUTH OF THE FRONT(71 AT BUFFALO,OK AND 65 AT LIBERAL). THE SFC DRYLINE WAS CURRENTLY MOVING NW THROUGH WEST TEXAS. AN UPPER LOW WAS SITUATED JUST OFF THE SOUTHERN CA COAST. 500MB TEMPS HAVE TURNED OUT TO BE WARMER THAN THE MODELS WERE FORECASTING A FEW DAYS AGO. IN FACT THE NAM HAS 500MB TEMPS AROUND -13C THIS AFTERNOON. SURFACE DEWPOINTS HAVE CLIMBED INTO THE UPPER 50S AND LOWER 60SF ACROSS OK/SOUTHERN KS. A LARGE AREA OF MID TO HIGH LEVEL CLOUD WAS MOVING NE INTO NM AND WEST TX. IN THE ABSENCE OF STRONG SYNOPTIC SCALE DYNAMICS TODAY...THE LOCATION OF SFC BOUNDARIES WILL DETERMINE THE PLACEMENT OF SHOWER/THUNDERSTORM INITIATION. THE NAM/GFS AND SOME OF THE RUC MEMBERS SURGE THE FRONT BACK TO THE NORTH TODAY TO A GCK TO HAYS LINE. I HAVE CHOSEN TO GO WITH THE RUC13 SOLUTION FOR TODAY. THIS MODEL KEEPS THE FRONT NEARLY STATIONARY ALL DAY. WITH BROKEN MID TO HIGH CLOUDS AND LOW LEVEL UPSLOPE FLOW... TEMPS WILL STAY IN THE 60S NORTH OF THE FRONT. BUT LOCATIONS ALONG THE OK STATE LINE COULD REACH THE UPPER 70S. I EXPECT THE SFC DRYLINE TO STRETCH FROM DALHART TO CARLSBAD,NM BY THIS AFTERNOON. THE DRYLINE WILL INTERSECT THE FRONT CLOSE TO DALHART. FAIRLY WEAK CAPPING...SOME ELEVATED HEATING ON THE HIGH PLAINS... AND CONVERGENCE ALONG THE DRYLINE AND NEAR THE FRONT/DRYLINE INTERSECTION WILL ALLOW STORMS TO DEVELOP BY 21Z. LOCAL POOLING OF MOISTURE MAY ALLOW FOR SFC BASED CAPES AS HIGH AS 1000-1500 J/KG FROM P28 TO ENGLEWOOD. AS STORMS MOVE INTO THIS AREA...A FEW OF THEM COULD BECOME SEVERE. VERTICAL SHEAR PROFILES WILL BE FAVORABLE FOR SEVERE STORMS. BUT THE MAIN LIMITING FACTOR FOR SEVERE STORMS WILL BE THE MARGINAL INSTABILITY. BUT AS WE HAVE SEEN IN THE RECENT PAST...STRONG VERTICAL WIND SHEAR AND CAPES AROUND 1000 J/KG CAN BE ENOUGH FOR SEVERE STORMS. ANY STORMS THAT DEVELOP THIS AFTERNOON WILL PROBABLY LINGER INTO TONIGHT. BUT THE STORM ACTIVITY WILL SHIFT OFF TO THE NE BY FRIDAY BEFORE THE MAIN UPPER LOW EJECTS INTO THE PLAINS ON SATURDAY. SOME POPS WERE MAINTAINED FOR FRIDAY FOR CONSISTENCY SAKE AND SINCE THERE IS SOME UNCERTAINTY. DAYS 3-7... NOT GOING TO CHANGE MUCH IN THE GOING EXTENDED. BOTH THE UKMET AND GFS BRING AN ORGANIZED SYSTEM UP FROM SOUTHERN BAHA CALIFORNIA TO WESTERN KANSAS FROM FRIDAY INTO SUNDAY. THE BEST CHANCES FOR PRECIPITATION LOOK TO BE ON SATURDAY AFTERNOON...WHERE WE HAVE 40 POPS GOING NOW. THESE POPS MAY HAVE TO BE RAISED IF THE TRACK OF THE UPPER SYSTEM BEARS OUT. TEMPERATURES LOOKED REASONABLE AND IN LINE WITH SURROUNDING WFO GRIDS. TUESDAY LOOKS TO BE WARM...PERHAPS WITH 80S SOMEWHERE IN OUR CWA. LEFT TUES MAX T`S ALONE FOR NOW...AS OUR SW HAS MID 70S GOING. && .AVIATION... AS LOW LEVEL MOISTURE CONTINUES TO CONVERGE ALONG AND SOUTH OF A FRONTAL BOUNDARY LYING ACROSS SOUTHERN KANSAS...STRATUS WILL LIKELY FORM AT DDC AND GCK IN THE 012 TO 015 FEET RANGE BY 11Z THIS MORNING. DO NOT EXPECT THE STRATUS TO LINGER MUCH BEYOND 15-16Z. ALSO...FOG WITH VSBYS IN THE 4-5SM RANGE WILL FORM AT DDC...GCK AND HYS AND LAST THROUGH 15Z. && .PRELIMINARY POINT TEMPS/POPS... DDC 68 53 71 56 / 20 30 20 20 GCK 64 45 72 53 / 20 20 20 20 EHA 71 47 71 53 / 20 20 20 20 LBL 73 51 71 56 / 20 30 20 20 HYS 61 48 72 55 / 20 20 20 20 P28 76 59 70 61 / 30 30 30 20 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ FN24/12 ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 200 AM MDT THU MAR 22 2007 .DISCUSSION... PRIMARY UPPER FEATURE FOR THE SHORT TERM PERIOD WILL BE CUT OFF LOW OVER THE DESERT SOUTHWEST. FORECAST AREA TO REMAIN UNDER THE SOUTHWEST FLOW AHEAD OF THE MAIN LOW FOR THE NEXT SEVERAL DAYS. THE UPPER LOW WILL THEN BEGIN TO LIFT NORTH/NORTHEAST OVER THE WEEKEND. UNFORTUNATELY MODELS IN POOR AGREEMENT ON FINER DETAILS. EVEN AS EARLY AS TODAY...NAM BRINGING A FAIRLY WELL DEFINED VORT MAX OVER THE AREA/WHEREAS GFS SHOWS LITTLE IF ANYTHING. WATER VAPOR IMAGERY INCONCLUSIVE...SINCE JUST SEE A BROAD SOUTHWEST FLOW WITH DEEP TROPICAL PLUME AHEAD OF THE MAIN LOW. WITH LITTLE TO GO ON WILL PLAY THE PERCENTAGES AND HAVE SOME SLIGHT/LOW CHANCE POPS THIS AFTERNOON AND EVENING ACROSS SOUTHEAST COUNTIES. SOMEWHAT RELIABLE RUC CEILING FORECAST SHOWS 2KFT BROKEN DECK OVERSPREADING THE CWA FROM THE SOUTH THIS AFTERNOON...WILL FAVOR COOLER GUIDANCE FOR HIGHS AS A RESULT. FRIDAY WILL BE A VIRTUAL REPEAT...THOUGH MODELS SWITCH PLACES WITH GFS WET AND NAM DRY. IT DOES APPEAR THE AREA WILL COME UNDER FAVORABLE RIGHT ENTRANCE REGION OF JET WHICH DEVELOPS FRIDAY NIGHT/SATURDAY MORNING OVER THE MIDWEST. SURFACE FRONT WILL ALSO BE SURGING NORTH INTO THE AREA. NONETHELESS...ISC CONSTRAINTS WILL DICTATE LOW CHANCE POPS. THEN WILL HAVE TO DEAL WITH THE MAIN LOW OVER THE WEEKEND. MODELS ALL OVER THE PLACE...WHICH LENDS LITTLE TO NO CONFIDENCE TO THE PRECIPITATION CHANCES. GFS ENSEMBLE AVERAGES GIVE SOLID CHANCE POPS THROUGH SATURDAY...GRADUALLY DIMINISHING SATURDAY NIGHT AND SUNDAY TO SLIGHT CHANCES. THE ENSEMBLE APPROACH SEEMS REASONABLE GIVEN THE UNCERTAINTIES. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ JDK ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 100 AM EDT FRI MAR 23 2007 AVIATION (06Z TAFS)... NO AVIATION CONCERNS THROUGH THE MORNING HOURS FRIDAY EXCEPT FOR SOME HIGH CLOUDINESS EXPECTED AT SDF AND LEX. THESE HIGH CLOUDS ARE CONVECTIVE DEBRIS CLOUDS DOWNSTREAM FROM WIDESPREAD CONVECTION ACROSS CENTRAL INDIANA AND ILLINOIS. SKIES WILL REMAIN CLEAR AT BWG OVERNIGHT. FOG FORMATION WILL NOT BE A FACTOR AS DECENT SOUTHERLY WINDS AT 1500FT (25KT) WILL KEEP THE BOUNDARY LAYER SOMEWHAT MIXED. ALSO NOTED THAT A 10-15 DEGREE DEWPOINT DEPRESSIONS ARE PRESENT EVEN NOW WITH THE LATEST SURFACE OBS. SKIES WILL BECOME INCREASINGLY CLOUDY LATE THIS AFTERNOON. SCATTERED SHOWER MAY DEVELOP AFTER 18Z ACROSS LEX AND SDF. CEILINGS WILL STAY VFR TOMORROW AFTERNOON EXCEPT UNDERNEATH ANY LOCAL SHOWERS. JSD && .PREV DISCUSSION... /ISSUED 729 PM EDT THU MAR 22 2007/ EVENING UPDATE... WEAK SURFACE WAVE MOVING ALONG THE BOUNDARY WELL TO THE NORTH ACROSS CENTRAL IL AND IN...LITTLE IF ANY SHRA ANYWHERE ACROSS THE FORECAST AREA. EVIDENT TREND ON THE VIS SAT AND REGIONAL RADARS THAT SLOW AND STEADY CLEARING OF CONVECTIVE DEBRIS FROM THE DAY...WITH BEST OMEGAS AND ANY INSTABILITY TO THE NORTH OF THE REGION. MID LEVEL CLOUDS DECREASING IN COVERAGE..WITH THINNING OF THE THICK CI FROM EARLIER STORMS. RUC AND 18Z RUNS OF GFS AND NAM LEADS ME TO LOWER POPS TO ISOLATED NORTH AND TO END ANYWHERE ALONG OR SOUTH OF THE OHIO RIVER FOR THE REST OF THE NIGHT. WITH SOME LESSENING OF THE SOUTHERLY WINDS AND SOME CLEARING NOW EXPECTED..WILL MONITOR FOR ANY HINT OF FOG DEVELOPMENT OVERNIGHT. --SCHOTT PREV DISCUSSION... /ISSUED 300 PM EDT THU MAR 22 2007/ SHORT TERM (TONIGHT AND FRIDAY)... SHORT RANGE MODEL GUIDANCE IN REASONABLE AGREEMENT FOR TNGT AND FRI. CURRENTLY SHORTWAVE IS PUSHING EWD OVER SERN CANADA JUST N OF GRT LAKES. SHORTWAVE TROF ACRS GRT LAKES HELPED CREATE SHWR ACTIVITY OVER OH VALLEY WITHIN DIFFLUENT FLOW ALOFT AND MODEST WARM ADVECTION. PRECIP HAS DIMINISHED OVER OUR AREA THIS AFTN...BUT AXIS OF SHWRS AND TSTMS STILL ACTIVE OVER SRN IL INTO FAR NWRN KY. WESTERLY FLOW ALOFT SUGGESTS SOME OF THESE SHWRS COULD PUSH BACK INTO NRN PARTS OF FCST AREA TNGT...SO WILL CONT WITH CHC/SCT PRECIP. SOUNDINGS SUGGEST ONLY MARGINAL INSTABILITY ALOFT SO STILL A FEW RUMBLES OF THUNDER PSBL TNGT BUT NOT EXPECTING SIGNIFY CNVCTN AT THIS TIME. FLOW PTRN PROGGED TO REMAIN WESTERLY ON FRI AS SFC FRONTAL BOUNDARY REMAINS LUST TO OUR NORTH. BOTH 12 UTC GFS AND NAM-WRF ARE FCSTG AREA OF INCREASING VERT MOTION AND PRECIP COMING OUT OF THE SRN PLAINS TNGT (AHEAD OF DEEP SWRN U.S. UPR LOW) AND INTO MID MS VALLEY FRI MRNG BEFORE TURNING EWD INTO LOWER OH VALLEY FRI AFTN AND EVNG. THIS WOULD BRING INCREASING CHCS OF PRECIP BACK ACRS PARTS OF CNTRL KY AND S-CNTRL IN FRI AFTN/EVNG. AGAIN INSTABILITY MARGINAL BUT EMBEDDED CNVCTN STILL EXPECTED ALONG WITH POTENTIAL FOR SOME TRAINING PRECIP ELEMENTS AND LOCALLY HEAVY RAINFALL NEAR TOP OF FLAT RIDGE AXIS ALOFT OVER OH VALLEY. CLOUDS AND SCT PRECIP THIS AFTN HAVE KEPT TEMPS LOWER ACRS NRN HALF OF FCST AREA. TEMPS TNGT SHOULD NOT FALL THAT FAR...AND WILL FCST MINS AT OR ABV GUIDANCE...WHICH WAS THE CASE LAST NGT/THIS MRNG. ON FRI...CLOUDS AND INCREASING RAIN CHCS ACRS THE NORTH AGAIN POSE A TEMP FCST CHALLENGE. MAV AND FWC BASED MOS SHOWING LOWER HI TEMPS THAN MET. GFS AND NAM-WRF MODEL SFC TEMPS ARE CONSISTENT WITH THEIR OWN CLOUD AND PRECIP FCST. GIVEN POP/CLOUD FCST IN GRIDS FOR FRI... HAVE LOWERED MAX TEMPS A FEW DEGREES. IF PRECIP DOES NOT MATERIALIZE AS MUCH AS EXPECTED OR CLOUDS ARE LESS DENSE...THEN HI TEMP VALUES WILL BE CLOSER TO HIGHER MET VALUES ON FRI. TWF LONG TERM (FRIDAY NIGHT THROUGH THURSDAY)... ECMWF CONTINUES TO BE THE MOST CONSISTENT MODEL AND HAS SOME SUPPORT FROM THE UKMET. WILL GENERALLY FOLLOW ECMWF FOR MOST OF EXTENDED. IN THE EARLY PERIODS NAM SUPPORTS SOME SUPPORT FOR HIGHER RH ALONG THE FRONT. FRIDAY NIGHT THROUGH SUNDAY NIGHT.. A FRONTAL BOUNDARY WILL BE NEARLY STATIONARY FROM WEST TO EAST ACROSS NORTHERN KENTUCKY TO CENTRAL ILLINOIS. SHOWERS AND THUNDERSTORMS WILL CONTINUE OVER THE AREA FRIDAY NIGHT WITH THE MOST NUMEROUS SHOWERS ACROSS THE NORTHERN PARTS OF THE FORECAST AREA AND CONSIDERABLY LOWER CHANCES NEAR THE TENNESSEE BORDER. THE SOUTHERLY BREEZES WILL KEEP WARM...MOIST AND UNSTABLE AIR OVER THE REGION...THUS WILL KEEP THUNDER IN THE FORECAST. ON SATURDAY THE FRONT WILL MOVE NORTH AS A WARM FRONT. THE SHOWERS WILL GRADUALLY COME TO AN END. THE TIMING OF THE ENDING OF THE RAIN AND CLOUDS DECREASING WILL AFFECT HOW WARM TEMPERATURES WILL GET. WILL KEEP TEMPS ACROSS THE FAR NORTHERN COUNTIES A LITTLE COOLER AS THIS AREA WILL BE THE LAST TO CLEAR. REST OF AREA SHOULD GET WELL INTO THE 70S. ON SUNDAY ENTIRE FORECAST AREA WILL BE WELL IN THE WARM SECTOR AND HIGHS COULD TOP 80 IN MANY LOCATIONS. MONDAY THROUGH THURSDAY... ON MONDAY CENTRAL KENTUCKY AND SOUTH CENTRAL INDIANA WILL STILL BE IN THE WARM SECTOR WITH A COLD FRONT DROPPING SOUTHEAST INTO SOUTHERN ILLINOIS BY TUESDAY MORNING. WILL ALLOW WIDELY SCATTERED THUNDERSTORMS TO DEVELOP MONDAY AFTERNOON AND SCATTERED STORMS MONDAY NIGHT THROUGH TUESDAY. THE NEXT CHANCE OF THUNDERSTORMS WILL COME WEDNESDAY NIGHT THROUGH THURSDAY AS WARM FRONT MOVES NORTH THROUGH THE AREA. HAVE STAYED CLOSE TO OR A LITTLE WARMER THAN HPC GUIDANCE TEMPERATURES. SCHOLZ && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PADUCAH KY 902 PM CDT THU MAR 22 2007 .UPDATE... FORECAST UPDATED MAINLY TO REMOVE EVENING WORDING. ADDED A SLIGHT CHANCE POP FOR SW INDIANA OVERNIGHT DUE TO THE CLOSE PROXIMITY OF THE SURFACE BOUNDARY. GRADUAL INCREASE IN CONVECTION NOTED OVER CENTRAL IL/CENTRAL MO/EASTERN KS OVER THE PAST COUPLE OF HOURS. THIS CONVECTION IS ALONG THE FRONT...WHICH THE MODELS KEEP QUASI STATIONARY FOR THE NEXT FEW DAYS. THIS CONVECTION MAY PROPAGATE SOUTHEAST AWAY FROM THE BOUNDARY INTO SRN ILLINOIS AND SE MISSOURI OVERNIGHT. RUC MODEL CORFIDI VECTORS INDICATE A SE MOVEMENT TO ANY ORGANIZED MCS THAT DEVELOPS. && .PREVIOUS DISCUSSION... MAIN CONCERNS FOR THIS FORECAST CONTINUE TO BE POPS THROUGH THE ENTIRE PERIOD...AS TEMPERATURES WILL REMAIN MILD THROUGHOUT. ELEVATED CONVECTION HAS SHRUNK DOWN TO A NARROW BAND OF SHOWERS RIGHT THROUGH THE MID-SECTION OF THE AREA...AND IT APPEARS TO BE WEAKENING AND FINALLY PUSHING OFF TO THE EAST. WITH THE AIRMASS THOROUGHLY WORKED OVER...AND THE SURFACE BOUNDARY WELL NORTH OF THE AREA...SEE LITTLE REASON TO HAVE MUCH POP IN THE AREA THIS EVENING. WILL HOWEVER...INCLUDE A SMALL CHANCE IN THE NORTHEAST IN AN ATTEMPT TO FIT IN TO SOME DEGREE WITH NEIGHBORS. OVERNIGHT...THE GFS IS A BIT FASTER BRINGING ANOTHER ROUND OF ELEVATED CONVECTION EASTWARD INTO THE REGION...AS ANOTHER MID-LEVEL DISTURBANCE BRINGS AN AREA OF LOW-LEVEL THETA-E ADVECTION INTO THE REGION. IF THE NAM IS RIGHT...THE CONVECTION WILL STAY TO OUR WEST THROUGH 12Z...BUT THE GFS BRINGS INTO OUR WEST JUST BEFORE 12Z. WILL MENTION A CHANCE OVERNIGHT IN THE WEST...AND THEN RAMP UP TO 50-60 POPS SOUTH TO NORTH ON FRIDAY. THIS SIGNAL HAS BEEN THERE FOR A COUPLE OF DAYS...HOWEVER...IF IT IS AS FOCUSED AS TODAYS CONVECTION HAS BEEN...SOME AREAS MAY NOT GET WET. THEREFORE WILL NOT GO HIGHER THAN 60S FOR NOW. THOSE 60S WILL BE IN THE NORTH WHERE THE MODELS ARE IN BETTER AGREEMENT WITH THE QPF. THE NAM IS NOT SURE ABOUT OUR SOUTHERN ZONES GETTING WET. MAY SEE SOME LINGERING CONVECTION FRIDAY NIGHT MAINLY NORTHEAST...SO WILL LEAVE A 20-30 POP ACROSS MUCH OF THE AREA. ON SATURDAY...THE FRONT RE-LOCATES WELL NORTH OF THE AREA...AND WILL KEEP THE FOCUS FOR CONVECTION TO OUR NORTH AS WELL. THE 12Z NAM TRIES TO REGENERATE CONVECTION ALL OVER THE AREA ON SATURDAY...BUT IT IS THE LONE MODEL THAT DOES NOT BUILD A MID/UPPER-LEVEL RIDGE THROUGH THE AREA. WILL THEREFORE IGNORE ITS SOLUTION FOR NOW. THE WEEKEND SHOULD BE QUITE GLORIOUS WITH TEMPS PUSHING 80 EACH AFTERNOON AND LOWS IN THE 50S. IN THE MEDIUM RANGE...EVEN THE ECMWF IS NOW TRYING TO DRAG SOME REMNANT OF THE SW U.S. CUT OFF LOW ACROSS THE AREA SOMETIME MONDAY OR TUESDAY. WILL THROW IN 20-30 POPS FOR THIS PERIOD WITH THE BEST CHANCES MONDAY NIGHT INTO TUESDAY. TUESDAY NIGHT AND WEDNESDAY LOOK DRY...BUT A MORE SIGNIFICANT SYSTEM MAY BEGIN TO EFFECT THE AREA ON THURSDAY OR FRIDAY. TEMPERATURES WILL CONTINUE TO BE WELL ABOVE NORMAL THROUGH THE ENTIRE 7 DAY PERIOD...WITH HIGHS IN THE 70S OR LOWER 80S AND LOWS IN THE 50S OR LOWER 60S. THE EXCEPTION WILL BE TOMORROW WHERE THE CONVECTION MAY HOLD TEMPS IN THE 60S. HOWEVER...IT IS NOT CERTAIN WHERE THE PRECIPITATION WILL BE FOCUSED ACROSS THE AREA TOMORROW. && .PAH WATCHES/WARNINGS/ADVISORIES... KY...NONE. MO...NONE. IL...NONE. IN...NONE. && $$ UPDATE...MY PREVIOUS...DRS ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 953 PM EDT THU MAR 22 2007 .UPDATE... SMALL UPDATE TO SLIGHTLY LOWER OVERNIGHT LOWS A DEGREE OR TWO ACROSS PORTIONS OR THE NORTHERN AREA AROUND SDF AND LEX...NOT SO MUCH ACROSS THE SOUTHERN HALF OF THE AREA. -SCHOTT && .PREV DISCUSSION... /ISSUED 729 PM EDT THU MAR 22 2007/ EVENING UPDATE... WEAK SURFACE WAVE MOVING ALONG THE BOUNDARY WELL TO THE NORTH ACROSS CENTRAL IL AND IN...LITTLE IF ANY SHRA ANYWHERE ACROSS THE FORECAST AREA. EVIDENT TREND ON THE VIS SAT AND REGIONAL RADARS THAT SLOW AND STEADY CLEARING OF CONVECTIVE DEBRIS FROM THE DAY...WITH BEST OMEGAS AND ANY INSTABILITY TO THE NORTH OF THE REGION. MID LEVEL CLOUDS DECREASING IN COVERAGE..WITH THINNING OF THE THICK CI FROM EARLIER STORMS. RUC AND 18Z RUNS OF GFS AND NAM LEADS ME TO LOWER POPS TO ISOLATED NORTH AND TO END ANYWHERE ALONG OR SOUTH OF THE OHIO RIVER FOR THE REST OF THE NIGHT. WITH SOME LESSENING OF THE SOUTHERLY WINDS AND SOME CLEARING NOW EXPECTED..WILL MONITOR FOR ANY HINT OF FOG DEVELOPMENT OVERNIGHT. --SCHOTT AVIATION DISCUSSION (00Z TAFS)... GRADUAL CLEARING APPEARS TO BE DEVELOPING IN THE LATEST VIS SAT LOOP...NOTHING OF ANY SIGNIFICANCE LOOKS TO EFFECT AVIATION CONCERNS THROUGH DAYBREAK FRIDAY. MODEST LOW LEVEL JET DEVELOPS TONIGHT BUT DOESN`T REACH THE 20 KNOTS GREATER THAN SFC WINDS TO MENTION IN THE TAFS...BUT 20 TO 25 KTS AROUND 1500 TO 2000 FEET LOOKS LIKELY OVERNIGHT. VFR CONDITIONS AT ALL THREE TAFS SITES LOOKS AS A GOOD BET THROUGH THE PERIOD...SOME SCATTERED SHOWER AND THUNDERSTORM ACTIVITY LOOKS TO PUSH SOUTH INTO THE NORTHERN TAF SITES OF SDF AND LEX AFTER 14 TO 18Z...WITH SHRA POSSIBLE AT BWG AFTER 22Z. --SCHOTT PREV DISCUSSION... /ISSUED 300 PM EDT THU MAR 22 2007/ SHORT TERM (TONIGHT AND FRIDAY)... SHORT RANGE MODEL GUIDANCE IN REASONABLE AGREEMENT FOR TNGT AND FRI. CURRENTLY SHORTWAVE IS PUSHING EWD OVER SERN CANADA JUST N OF GRT LAKES. SHORTWAVE TROF ACRS GRT LAKES HELPED CREATE SHWR ACTIVITY OVER OH VALLEY WITHIN DIFFLUENT FLOW ALOFT AND MODEST WARM ADVECTION. PRECIP HAS DIMINISHED OVER OUR AREA THIS AFTN...BUT AXIS OF SHWRS AND TSTMS STILL ACTIVE OVER SRN IL INTO FAR NWRN KY. WESTERLY FLOW ALOFT SUGGESTS SOME OF THESE SHWRS COULD PUSH BACK INTO NRN PARTS OF FCST AREA TNGT...SO WILL CONT WITH CHC/SCT PRECIP. SOUNDINGS SUGGEST ONLY MARGINAL INSTABILITY ALOFT SO STILL A FEW RUMBLES OF THUNDER PSBL TNGT BUT NOT EXPECTING SIGNIF CNVCTN AT THIS TIME. FLOW PTRN PROGGED TO REMAIN WESTERLY ON FRI AS SFC FRONTAL BOUNDARY REMAINS LUST TO OUR NORTH. BOTH 12 UTC GFS AND NAM-WRF ARE FCSTG AREA OF INCREASING VERT MOTION AND PRECIP COMING OUT OF THE SRN PLAINS TNGT (AHEAD OF DEEP SWRN U.S. UPR LOW) AND INTO MID MS VALLEY FRI MRNG BEFORE TURNING EWD INTO LOWER OH VALLEY FRI AFTN AND EVNG. THIS WOULD BRING INCREASING CHCS OF PRECIP BACK ACRS PARTS OF CNTRL KY AND S-CNTRL IN FRI AFTN/EVNG. AGAIN INSTABILITY MARGINAL BUT EMBEDDED CNVCTN STILL EXPECTED ALONG WITH POTENTIAL FOR SOME TRAINING PRECIP ELEMENTS AND LOCALLY HEAVY RAINFALL NEAR TOP OF FLAT RIDGE AXIS ALOFT OVER OH VALLEY. CLOUDS AND SCT PRECIP THIS AFTN HAVE KEPT TEMPS LOWER ACRS NRN HALF OF FCST AREA. TEMPS TNGT SHOULD NOT FALL THAT FAR...AND WILL FCST MINS AT OR ABV GUIDANCE...WHICH WAS THE CASE LAST NGT/THIS MRNG. ON FRI...CLOUDS AND INCREASING RAIN CHCS ACRS THE NORTH AGAIN POSE A TEMP FCST CHALLENGE. MAV AND FWC BASED MOS SHOWING LOWER HI TEMPS THAN MET. GFS AND NAM-WRF MODEL SFC TEMPS ARE CONSISTENT WITH THEIR OWN CLOUD AND PRECIP FCST. GIVEN POP/CLOUD FCST IN GRIDS FOR FRI... HAVE LOWERED MAX TEMPS A FEW DEGREES. IF PRECIP DOES NOT MATERIALIZE AS MUCH AS EXPECTED OR CLOUDS ARE LESS DENSE...THEN HI TEMP VALUES WILL BE CLOSER TO HIGHER MET VALUES ON FRI. TWF LONG TERM (FRIDAY NIGHT THROUGH THURSDAY)... ECMWF CONTINUES TO BE THE MOST CONSISTENT MODEL AND HAS SOME SUPPORT FROM THE UKMET. WILL GENERALLY FOLLOW ECMWF FOR MOST OF EXTENDED. IN THE EARLY PERIODS NAM SUPPORTS SOME SUPPORT FOR HIGHER RH ALONG THE FRONT. FRIDAY NIGHT THROUGH SUNDAY NIGHT.. A FRONTAL BOUNDARY WILL BE NEARLY STATIONARY FROM WEST TO EAST ACROSS NORTHERN KENTUCKY TO CENTRAL ILLINOIS. SHOWERS AND THUNDERSTORMS WILL CONTINUE OVER THE AREA FRIDAY NIGHT WITH THE MOST NUMEROUS SHOWERS ACROSS THE NORTHERN PARTS OF THE FORECAST AREA AND CONSIDERABLY LOWER CHANCES NEAR THE TENNESSEE BORDER. THE SOUTHERLY BREEZES WILL KEEP WARM...MOIST AND UNSTABLE AIR OVER THE REGION...THUS WILL KEEP THUNDER IN THE FORECAST. ON SATURDAY THE FRONT WILL MOVE NORTH AS A WARM FRONT. THE SHOWERS WILL GRADUALLY COME TO AN END. THE TIMING OF THE ENDING OF THE RAIN AND CLOUDS DECREASING WILL AFFECT HOW WARM TEMPERATURES WILL GET. WILL KEEP TEMPS ACROSS THE FAR NORTHERN COUNTIES A LITTLE COOLER AS THIS AREA WILL BE THE LAST TO CLEAR. REST OF AREA SHOULD GET WELL INTO THE 70S. ON SUNDAY ENTIRE FORECAST AREA WILL BE WELL IN THE WARM SECTOR AND HIGHS COULD TOP 80 IN MANY LOCATIONS. MONDAY THROUGH THURSDAY... ON MONDAY CENTRAL KENTUCKY AND SOUTH CENTRAL INDIANA WILL STILL BE IN THE WARM SECTOR WITH A COLD FRONT DROPPING SOUTHEAST INTO SOUTHERN ILLINOIS BY TUESDAY MORNING. WILL ALLOW WIDELY SCATTERED THUNDERSTORMS TO DEVELOP MONDAY AFTERNOON AND SCATTERED STORMS MONDAY NIGHT THROUGH TUESDAY. THE NEXT CHANCE OF THUNDERSTORMS WILL COME WEDNESDAY NIGHT THROUGH THURSDAY AS WARM FRONT MOVES NORTH THROUGH THE AREA. HAVE STAYED CLOSE TO OR A LITTLE WARMER THAN HPC GUIDANCE TEMPERATURES. SCHOLZ AVIATION (18Z TAFS)... SCT TO NUMEROUS SHOWERS WILL STREAM EWD THRU THE AFTN ALONG AND EITHER SIDE OF OH RIVER. STILL A CONVECTIVE THREAT BUT CG LIGHTNING ACTIVITY GRADUALLY DIMINISHING AT THIS TIME. KLVX VWP PROFILE SHOWS UNIFORM SWLY FLOW IN LOW-LEVELS WITH ONLY MODEST INCREASE IN SPEED WITH HEIGHT...THUS LOW-LEVEL WIND SHEAR NO LONGER A SIGNIFICANT HAZARD. CIGS MAY OCCASIONALLY FALL INTO MVFR CATEGORY BUT GENERALLY CIGS EXPECTED ABOVE 3KFT (VFR) DURING FCST PD. AS SHORTWAVE TO OUR N PULLS OUT...PRECIP SHOULD BE MORE SCT LATE TNGT AND EARLY FRI...BEFORE MODELS SHOW NEXT SURGE OF MOISTURE AND PRECIP ARRIVING FRI AFTN. TWF LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 729 PM EDT THU MAR 22 2007 .EVENING UPDATE... WEAK SURFACE WAVE MOVING ALONG THE BOUNDARY WELL TO THE NORTH ACROSS CENTRAL IL AND IN...LITTLE IF ANY SHRA ANYWHERE ACROSS THE FORECAST AREA. EVIDENT TREND ON THE VIS SAT AND REGIONAL RADARS THAT SLOW AND STEADY CLEARING OF CONVECTIVE DEBRIS FROM THE DAY...WITH BEST OMEGAS AND ANY INSTABILITY TO THE NORTH OF THE REGION. MID LEVEL CLOUDS DECREASING IN COVERAGE..WITH THINNING OF THE THICK CI FROM EARLIER STORMS. RUC AND 18Z RUNS OF GFS AND NAM LEADS ME TO LOWER POPS TO ISOLATED NORTH AND TO END ANYWHERE ALONG OR SOUTH OF THE OHIO RIVER FOR THE REST OF THE NIGHT. WITH SOME LESSENING OF THE SOUTHERLY WINDS AND SOME CLEARING NOW EXPECTED..WILL MONITOR FOR ANY HINT OF FOG DEVELOPMENT OVERNIGHT. --SCHOTT && .AVIATION DISCUSSION (00Z TAFS)... GRADUAL CLEARING APPEARS TO BE DEVELOPING IN THE LATEST VIS SAT LOOP...NOTHING OF ANY SIGNIFICANCE LOOKS TO EFFECT AVIATION CONCERNS THROUGH DAYBREAK FRIDAY. MODEST LOW LEVEL JET DEVELOPS TONIGHT BUT DOESN`T REACH THE 20 KNOTS GREATER THAN SFC WINDS TO MENTION IN THE TAFS...BUT 20 TO 25 KTS AROUND 1500 TO 2000 FEET LOOKS LIKELY OVERNIGHT. VFR CONDITIONS AT ALL THREE TAFS SITES LOOKS AS A GOOD BET THROUGH THE PERIOD...SOME SCATTERED SHOWER AND THUNDERSTORM ACTIVITY LOOKS TO PUSH SOUTH INTO THE NORTHERN TAF SITES OF SDF AND LEX AFTER 14 TO 18Z...WITH SHRA POSSIBLE AT BWG AFTER 22Z. --SCHOTT && .PREV DISCUSSION... /ISSUED 300 PM EDT THU MAR 22 2007/ SHORT TERM (TONIGHT AND FRIDAY)... SHORT RANGE MODEL GUIDANCE IN REASONABLE AGREEMENT FOR TNGT AND FRI. CURRENTLY SHORTWAVE IS PUSHING EWD OVER SERN CANADA JUST N OF GRT LAKES. SHORTWAVE TROF ACRS GRT LAKES HELPED CREATE SHWR ACTIVITY OVER OH VALLEY WITHIN DIFFLUENT FLOW ALOFT AND MODEST WARM ADVECTION. PRECIP HAS DIMINISHED OVER OUR AREA THIS AFTN...BUT AXIS OF SHWRS AND TSTMS STILL ACTIVE OVER SRN IL INTO FAR NWRN KY. WESTERLY FLOW ALOFT SUGGESTS SOME OF THESE SHWRS COULD PUSH BACK INTO NRN PARTS OF FCST AREA TNGT...SO WILL CONT WITH CHC/SCT PRECIP. SOUNDINGS SUGGEST ONLY MARGINAL INSTABILITY ALOFT SO STILL A FEW RUMBLES OF THUNDER PSBL TNGT BUT NOT EXPECTING SIGNIF CNVCTN AT THIS TIME. FLOW PTRN PROGGED TO REMAIN WESTERLY ON FRI AS SFC FRONTAL BOUNDARY REMAINS LUST TO OUR NORTH. BOTH 12 UTC GFS AND NAM-WRF ARE FCSTG AREA OF INCREASING VERT MOTION AND PRECIP COMING OUT OF THE SRN PLAINS TNGT (AHEAD OF DEEP SWRN U.S. UPR LOW) AND INTO MID MS VALLEY FRI MRNG BEFORE TURNING EWD INTO LOWER OH VALLEY FRI AFTN AND EVNG. THIS WOULD BRING INCREASING CHCS OF PRECIP BACK ACRS PARTS OF CNTRL KY AND S-CNTRL IN FRI AFTN/EVNG. AGAIN INSTABILITY MARGINAL BUT EMBEDDED CNVCTN STILL EXPECTED ALONG WITH POTENTIAL FOR SOME TRAINING PRECIP ELEMENTS AND LOCALLY HEAVY RAINFALL NEAR TOP OF FLAT RIDGE AXIS ALOFT OVER OH VALLEY. CLOUDS AND SCT PRECIP THIS AFTN HAVE KEPT TEMPS LOWER ACRS NRN HALF OF FCST AREA. TEMPS TNGT SHOULD NOT FALL THAT FAR...AND WILL FCST MINS AT OR ABV GUIDANCE...WHICH WAS THE CASE LAST NGT/THIS MRNG. ON FRI...CLOUDS AND INCREASING RAIN CHCS ACRS THE NORTH AGAIN POSE A TEMP FCST CHALLENGE. MAV AND FWC BASED MOS SHOWING LOWER HI TEMPS THAN MET. GFS AND NAM-WRF MODEL SFC TEMPS ARE CONSISTENT WITH THEIR OWN CLOUD AND PRECIP FCST. GIVEN POP/CLOUD FCST IN GRIDS FOR FRI... HAVE LOWERED MAX TEMPS A FEW DEGREES. IF PRECIP DOES NOT MATERIALIZE AS MUCH AS EXPECTED OR CLOUDS ARE LESS DENSE...THEN HI TEMP VALUES WILL BE CLOSER TO HIGHER MET VALUES ON FRI. TWF LONG TERM (FRIDAY NIGHT THROUGH THURSDAY)... ECMWF CONTINUES TO BE THE MOST CONSISTENT MODEL AND HAS SOME SUPPORT FROM THE UKMET. WILL GENERALLY FOLLOW ECMWF FOR MOST OF EXTENDED. IN THE EARLY PERIODS NAM SUPPORTS SOME SUPPORT FOR HIGHER RH ALONG THE FRONT. FRIDAY NIGHT THROUGH SUNDAY NIGHT.. A FRONTAL BOUNDARY WILL BE NEARLY STATIONARY FROM WEST TO EAST ACROSS NORTHERN KENTUCKY TO CENTRAL ILLINOIS. SHOWERS AND THUNDERSTORMS WILL CONTINUE OVER THE AREA FRIDAY NIGHT WITH THE MOST NUMEROUS SHOWERS ACROSS THE NORTHERN PARTS OF THE FORECAST AREA AND CONSIDERABLY LOWER CHANCES NEAR THE TENNESSEE BORDER. THE SOUTHERLY BREEZES WILL KEEP WARM...MOIST AND UNSTABLE AIR OVER THE REGION...THUS WILL KEEP THUNDER IN THE FORECAST. ON SATURDAY THE FRONT WILL MOVE NORTH AS A WARM FRONT. THE SHOWERS WILL GRADUALLY COME TO AN END. THE TIMING OF THE ENDING OF THE RAIN AND CLOUDS DECREASING WILL AFFECT HOW WARM TEMPERATURES WILL GET. WILL KEEP TEMPS ACROSS THE FAR NORTHERN COUNTIES A LITTLE COOLER AS THIS AREA WILL BE THE LAST TO CLEAR. REST OF AREA SHOULD GET WELL INTO THE 70S. ON SUNDAY ENTIRE FORECAST AREA WILL BE WELL IN THE WARM SECTOR AND HIGHS COULD TOP 80 IN MANY LOCATIONS. MONDAY THROUGH THURSDAY... ON MONDAY CENTRAL KENTUCKY AND SOUTH CENTRAL INDIANA WILL STILL BE IN THE WARM SECTOR WITH A COLD FRONT DROPPING SOUTHEAST INTO SOUTHERN ILLINOIS BY TUESDAY MORNING. WILL ALLOW WIDELY SCATTERED THUNDERSTORMS TO DEVELOP MONDAY AFTERNOON AND SCATTERED STORMS MONDAY NIGHT THROUGH TUESDAY. THE NEXT CHANCE OF THUNDERSTORMS WILL COME WEDNESDAY NIGHT THROUGH THURSDAY AS WARM FRONT MOVES NORTH THROUGH THE AREA. HAVE STAYED CLOSE TO OR A LITTLE WARMER THAN HPC GUIDANCE TEMPERATURES. SCHOLZ AVIATION (18Z TAFS)... SCT TO NUMEROUS SHOWERS WILL STREAM EWD THRU THE AFTN ALONG AND EITHER SIDE OF OH RIVER. STILL A CONVECTIVE THREAT BUT CG LIGHTNING ACTIVITY GRADUALLY DIMINISHING AT THIS TIME. KLVX VWP PROFILE SHOWS UNIFORM SWLY FLOW IN LOW-LEVELS WITH ONLY MODEST INCREASE IN SPEED WITH HEIGHT...THUS LOW-LEVEL WIND SHEAR NO LONGER A SIGNIFICANT HAZARD. CIGS MAY OCCASIONALLY FALL INTO MVFR CATEGORY BUT GENERALLY CIGS EXPECTED ABOVE 3KFT (VFR) DURING FCST PD. AS SHORTWAVE TO OUR N PULLS OUT...PRECIP SHOULD BE MORE SCT LATE TNGT AND EARLY FRI...BEFORE MODELS SHOW NEXT SURGE OF MOISTURE AND PRECIP ARRIVING FRI AFTN. TWF LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 1048 AM EDT THU MAR 22 2007 .SHORT TERM /REST OF TODAY/... AREA MORNING UPPER AIR SOUNDINGS SHOW LAYERED MOISTURE THROUGH MUCH OF THE COLUMN. SFC OBS/SATL DATA CONFIRMS SCT-BKN MULTILAYERED CLOUDS ACRS FORECAST AREA THIS LATE MORNING BUT THE CLOUD PATCHES APPEAR TO BE BREAKING AND THINNING. THEREFORE EXPECT SKY CONDITION WILL AVERAGE PTSUNNY DURING THE AFTN. INSOLATION SHUD BE SUFFICIENT TO ALLOW TEMPS TO REACH FCSTD VALUES RANGING FROM M60S ACRS THE EASTERN SHORE TO M70S OVER PIEDMONT...BUT OF COURSE COOLER WHERE FLOW IS ONSHORE. LTL IF ANY CHANGES NEEDED TO FCST ATTM BUT UPDATED FCST TO REFRESH PRODUCTS. .MARINE UPDATE... DECIDED TO ADD SCA FOR THE CHESAPEAKE BAY WTRS FROM SMITH POINT TO NEW POINT COMFORT...WITH 15-20 KT WINDS AND 2-3 FT WAVES. RUC AND NAM MODELS SUGGEST INCRSG SFC WINDS AFTER 18Z. SOUNDINGS SHOW AROUND 15 KT AT SFC UNDER WEAK INVERSION WITH 25-30 KTS ABOVE INVERSION. EXPECT ENOUGH MIXING TO ALLOW 20 KT GUSTS DOWN TO SFC. STRONGER LOW LEVEL INVERSION TO SOUTH OF NEW POINT COMFORT SO OPTED NOT TO GO FOR SCA FOR SOUTHERN BAY BUT STEADY 15 KT. ON CSTL WTRS...EXPECT 15-20 KT SOUTH WINDS FROM FENWICK DOWN TO PARRAMORE WITH LONGER FETCH BUILDING SEAS TO SCA CRITERIA AFTER 2 PM. DIFFICULT FCST FOR THE WEEKEND WITH BACKDOOR COLD FRONT SAT/SAT NGT. HAVE DECIDED TO GO CLOSER TO NAM/UKMET (GFS IS OUTLIER)...KEEPING SW FLOW SRN ZONES ON SAT...ELY FLOW ACRS THE NORTH. THEN...FRONT CLEARS ENTIRE MARINE AREA SAT NGT/SUN...WITH NNE FLOW AND POSSIBLE SMALL CRAFT CONDITIONS AT THAT TIME. && .PREV DISCUSSION... /ISSUED 513 AM EDT THU MAR 22 2007/ SHORT TERM /TODAY THROUGH SATURDAY NIGHT/... CURRENTLY...HIGH PRESSURE CONTINUES TO PUSH OFFSHORE WHILE A COLD FRONT ADVANCES EAST THROUGH THE WESTERN GREAT LAKES AND MIDWEST REGIONS. THE MAIN FORECAST CONERN TODAY WILL BE WITH CLOUD COVER EXTENT (DEPTH) AND THUS IMPACT ON TEMPS. GFS/NAM ARE IN FAIRLY CLOSE ACCORD IN THE SHORT TERM (THROUGH TONIGHT). BOTH INDICATE THE COLD FRONT DROPPING TO NEAR THE MASON- DIXON LINE BY MIDNIGHT TONIGHT...BECOMING MORE W-E ORIENTED AS THE ASSOCIATED UPPER LEVEL VORT LOBE ENCOUNTERS A ZONAL/FLAT UPPER RIDGE. PRE-FRONTAL FORCING/MOISTURE IS INSUFFICIENT FOR POPS ACROSS THE FCST AREA TODAY. AS FOR SKY COVER...EXPECT THE LOWER CLOUDS TO SCOUR OUT LATER THIS MORNING/AFTN AS THE LOW LEVEL FLOW VEERS TOWARD THE S-SW RESULTING IN MORE APPRECIABLE WARMING (AND RELATIVE DRYING) WITHING THE 1000-850 MB LAYER. STILL EXPECT PERIODIC WAVES OF HIGHER BASED CLOUDS IN THE AFTN AS WE GET INTO THE WARM SECTOR...THUS HAVE WORDED PARTLY SUNNY. BASED ON RECENT TRENDS (YDAY)...HAVE GONE A FEW DEGREES HIGHER THAN MOS TODAY FOR HIGH TEMPS. THIS BASED ON THE LOW LEVEL WAA AND INCREASED SUNSHINE THIS AFTN (ANTICIPATED DEEPER MIXING WITH THE LATE MARCH SUN ANGLE). TONIGHT...FRONT DIPS INTO NRN VA AND THE NRN PTN OF THE DELMARVA. HAVE INCLUDED LOW (30-40%) POPS OVER THE NRN THIRD OF THE CWA CLOSEST TO THE FRONT...THOUGH ONCE AGAIN WITH THE FLATTENING UPPER FLOW (AND NEGLIGIBLE STRAIGHT UPPER JET FORCING)...DYNAMICS AND THUS MOISTURE DEPTHS REMAIN LACKING. S OF FVX-RIC-MFV...MOISTURE IS JUST TOO SHALLOW (PARTICULARLY IN LOW LEVELS) FOR POPS. FRIDAY...COMPARED TO THE NAM/UKMET/ECMWF...THE 00Z GFS IS TOO QUICK WITH THE INITIAL IMPULSE TRACKING FROM THE UPPER MIDWEST- OH VLY-MID ATLC REGION. SIDING MORE TOWARD A NAM/ECMWF BLEND... EXPECT A NW-SE DRAPED SURFACE FRONTAL BNDRY ACROSS THE FCST AREA... WITH THE FRONT TAKING ON THE TYPICAL "SAG" EAST TOWARD THE COOLER COASTAL WATERS. AS A RESULT EXPECT A LARGE TEMP GRADIENT FROM SW-NE... I.E. AROUND 80/LOWER 80S INLAND TO AROUND 60 ALONG THE LOWER ERN SHORE. WILL ALSO MAINTAIN MORE EXTENSIVE CLOUD COVER/LOW POPS OVER THE N-NE ZONES ALONG AND N OF THE PROJECTED FRONTAL ZONE. SATURDAY...GFS IS MUCH COOLER WITH THE LOWER LEVELS COMPARED TO THE OTHER MODELS...BASICALLY A CONSEQUENCE OF THIS MODEL BEING TOO PROGRESSIVE WITH THE INITIAL UPPER SHORTWAVE/WEAK SURFACE LOW ALONG THE STATIONARY FRONT. GFS (MAV) MOS GUIDANCE IN FACT IS SOME 20+ DEGREES COOLER WITH HIGH TEMPS OVER INLAND LOCALES COMPARED TO THE NAM (MET) GUIDANCE! FOR NOW WILL CONTINUE TO LEAN MORE TOWARD THE NAM/ ECMWF...WHICH DOES NOT DROP THE FRONT S OF THE LOWER DELMARVA UNTIL LATE IN THE DAY. BASED ON THESE PROJECTIONS...EXPECT ANOTHER DAY WITH A SIGNIFICANT TEMPERATURE GRADIENT FROM SW (80-85) TO AREAS ALONG THE ATLANTIC SIDE OF THE LOWER MD ERN SHORE (LOW-MID 50S). LONG TERM /SUNDAY THROUGH WEDNESDAY/... BASED ON THE LATEST NAM/ECWMF TRENDS...AND WITH THE LOWER CONFIDENCE IN THE GFS SAT-SUN...DID NOT MAKE TOO MANY CHANGES TO THE FCSTS DURING THE EXTENDED PERIODS. HIGH PRESSURE BUILDING FROM THE N AND EVENTUALLY NE (OFFSHORE) ON SUNDAY WILL MAKE FOR A COOLER DAY OVER THE NERN PTNS OF THE FCST AREA...THOUGH AGAIN EXPECT TEMPS TO REMAIN MUCH MILDER AS YOU HEAD FARTHER SW. TOWARD PETERSBURG/FARMVILLE/SOUTH HILL. AVIATION...VARIABLE CONDITIONS EARLY THIS MORNING...HAVE MVFR CIGS NORTH AND WEST...VFR SOUTH. FLOW TURNS TO S OR SW LATER TODAY WITH INCREASING WIND SPEEDS BY AFTN...AND MAINLY VFR CONDS. MVFR CIGS MAY HANG TOUGH ON THE ERN SHORE THRU 16-18Z. CONTINUED VFR TONIGHT AS MIXING SHOULD INHIBIT SIGNIFICANT FOG FORMATION. MARINE...GRADIENT INCREASES FROM SOUTH TO SOUTHWEST LATER TODAY. CHILLY BAY WATERS WILL MAKE IT DIFFICULT TO EFFICIENTLY MIX THESE WINDS DOWN TO THE SFC...SO OPTED TO KEEP CONDITIONS ON THE BAY & SOUND BELOW SMALL CRAFT (ALTHOUGH IT WILL BE CLOSE LATER THIS AFTN). ON COASTAL WATERS...INCREASING SOUTHERLY FLOW (NEAR 20 KTS BY AFTN) WILL LIKELY BRING SEAS TO MARGINAL SMALL CRAFT CONDITIONS (5 FT WAVES OFFSHORE) N OF PARRAMORE ISL...FROM LATER IN THE AFTN THROUGH ERLY MRNG THU. DIFFICULT FCST FOR THE WEEKEND WITH BACKDOOR COLD FRONT SAT/SAT NGT. HAVE DECIDED TO GO CLOSER TO NAM/UKMET (GFS IS OUTLIER)...KEEPING SW FLOW SRN ZONES ON SAT...ELY FLOW ACRS THE NORTH. THEN...FRONT CLEARS ENTIRE MARINE AREA SAT NGT/SUN...WITH NNE FLOW AND POSSIBLE SMALL CRAFT CONDITIONS AT THAT TIME. FIRE WEATHER...LIGHT SE TO S FLOW THIS MRNG...WITH GUSTY SOUTH...SOUTHWEST WINDS INCREASING BY AFTN FOR MUCH OF INLAND VA. HOWEVER...NOT REALLY A DOWNSLOPE FLOW SO RH VALUES DO NOT DROP OFF THAT MUCH...WITH MOST LOCATIONS BOTTOMING OUT 35-45% AT THE DRIEST. FARTHER EAST...COOLER TEMPERATURES WILL TEND TO INHIBIT MIXING SOMEWHAT SO WINDS LIKELY STAY MORE FROM DUE SOUTH AT 15 KTS OR LESS. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 2 AM EDT FRIDAY FOR ANZ630-631-650-652. && $$ SHORT TERM UPDATE...CULLEN/FOSTER md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1120 PM EDT FRI MAR 23 2007 .UPDATE...HAVE EXTENDED THE FLOOD WARNING FOR ARENAC COUNTY AS THE RIFLE RIVER IS STILL A LITTLE LESS THAN A FOOT ABOVE FLOOD STAGE (8.72 FEET AT 11 PM). WOULD EXPECT THAT THE RIVER WILL BE BELOW FLOOD STAGE BY THE AFTERNOON. HOWEVER, HAVE EXTENDED THE WARNING OUT FAR ENOUGH SO THAT IF IT TAKES LONGER THE DAY SHIFT WILL BE ABLE TO COMFORTABLY DEAL WITH IT. LUTZ && .UPDATE...ISSUED 1007 PM MAIN CONCERN IS FOR THE CLOUD COVER AND ANY RAIN CHANCES FOR THE N LOWER OVERNIGHT. MID CLOUDS HAVE BEEN MAKING THEIR WAY INTO THE SW PORTION OF THE FORECAST AREA WITH MOST OF THE LOWER CLOUDS STAYING SOUTH OF M-55. THE NAM LOOKS TO BE HANDLING THIS SITUATION THE BEST WITH THE TIME-HEIGHT SECTIONS OVER THE TVC SHOWING THAT THE LOWEST CLOUDS WILL PROBABLY STAY SOUTH WITH THE MOISTURE KEEPING THE AT OR ABOVE 3000FT. SO THE MAIN THING WILL BE CLOUDING THE FORECAST TONIGHT FASTER AND ADDING A CHANCE OF RAIN SHOWERS FOR THE OVERNIGHT. LUTZ && .AVIATION...ISSUED 819 PM HAVE BEEN TIMING THE CLOUD COVER THAT WILL AFFECT TVC FIRST AND THEN PLN AND APN. THE TIMING LOOKS CONSISTENT WITH THE NAM AND RUC MODELS AND SUBSEQUENTLY THE ACTUAL TAFS. SO HAVE LEFT THE FIRST 6 HOURS ALONE FOR THE MOST PART AS THE LOWEST CLOUDS LOOK TO STAYING SOUTH OF THE FORECAST AREA. OTHERWISE, THE CLOUDS WILL MOVE OVER THE N LOWER OVERNIGHT AND THEN MOVE OUT BY THE LATE AFTERNOON ON SATURDAY AS THE 500 MB TROUGH MOVES THROUGH THE REGION. LUTZ && .PREV DISCUSSION...ISSUED 349 PM HIGH PRESSURE/DRY AIR REMAINS IN CONTROL ACROSS NRN MICHIGAN THIS AFTERNOON. AREA OF THICKER MID CLOUD ASSOCIATED WITH WEAK SHORT WAVE (PER WATER VAPOR IMAGERY) PASSING THROUGH THE UPPER PENINSULA CONTINUING TO PRODUCE SCT-BKN MID CLOUD OVER THE NRN PORTION OF THE CWA AND WILL CONTINUE TO DO SO INTO THE EVENING PER SATELLITE TRENDS. TO THE SOUTH...ACTIVE BAROCLINIC ZONE DRAPED OVER THE OHIO VALLEY PRODUCING PERSISTENT RAINFALL JUST SOUTH OF THE STATE (MORE ON THAT BELOW). TO THE WEST...STRONGER NRN STREAM SHORT WAVE CROSS THE U.S./CANADIAN BORDER NEAR THE DAKOTAS AND WILL BE PASSING THROUGH THE REGION SATURDAY. TONIGHT THROUGH SATURDAY...12Z MODEL GUIDANCE OFFERING A DIFFERENT SCENARIO OVER THE NEXT 24 HOURS VERSUS PREVIOUS RUNS...SPECIFICALLY IN THEIR HANDLING OF THE WAVY BAROCLINIC ZONE TO THE SOUTH. 12Z NAM/GFS HAVE TRENDED A BIT MORE BULLISH...DRAWING A SUBSTANTIAL AMOUNT OF LOW LEVEL MOISTURE UP INTO NORTHERN MICHIGAN LATER THIS EVENING AND OVERNIGHT WHILE SOME SEMBLANCE OF A WEAK LOW LEVEL CIRCULATION PASSES THROUGH NRN LOWER MICHIGAN. THIS CERTAINLY APPEARS TO BE THE TREND AS VISIBLE SATELLITE IMAGERY REVEALING WALL OF STRATUS MAKING STEADY PROGRESS NORTHWARD THROUGH SRN WISCONSIN AND SRN LOWER MICHIGAN THIS AFTERNOON AND HAVE THUS TRENDED THE FORECAST TOWARD THE CLOUDIER SIDE OF THINGS OVERNIGHT THROUGH SATURDAY MIDDAY. CANNOT RULE OUT THE POSSIBILITIES FOR SOME PRECIP PARTICULARLY SATURDAY MORNING AS NRN STREAM WAVE MOVES THROUGH. BUT NAM/GFS FORECAST SOUNDINGS A BIT SHALLOW WITH THE MOISTURE - PRIMARILY WARMER THAN 0C. IF ANYTHING...CAN SEE SOME DRIZZLE DEVELOPING UP INTO THE HIGHER TERRAIN WITH SOME SEMBLANCE OF AN UPSLOPE FLOW. BUT HAVE KEPT THE FORECAST FOR MOST OF NRN LOWER MICHIGAN DRY FOR NOW. MEANWHILE...AFOREMENTIONED MID LEVEL SHORT WAVE COMING OUT OF THE NRN PLAINS AND THROUGH THE NRN PART OF THE STATE OVERNIGHT THROWS YET ANOTHER WRENCH INTO THE FORECAST. DECENT POCKET OF ASSOCIATED MID LEVEL QG UPWARD FORCING SWEEPING THROUGH THE NRN HALF OF THE STATE LATE OVERNIGHT AND SATURDAY MORNING/COMBINED WITH BETTER MID LEVEL MOISTURE MAY BE ENOUGH TO SQUEEZE OUT SOME LIGHT MEASURABLE RAINFALL ACROSS THE U.P. AND TIP OF THE MITT COUNTIES. SO PLAN IS TO CARRY LOW CHANCE POPS FOR THOSE AREAS OVERNIGHT THROUGH MIDDAY. MAY GET LOCKED INTO THE LOW CLOUD COVER THROUGH MUCH OF THE DAY SATURDAY. HOWEVER...DRIER AIR/RIDGING LOOKING TO BUILD BACK INTO THE REGION LATE IN THE DAY AND SHOULD HOPEFULLY BEGIN TO CLEAR THINGS OUT AS WE GO THROUGH THE AFTERNOON. HYDRO CONCERNS...USGS GAGE READINGS ON THE TOBACCO AND RIFLE RIVERS NOW STARTING TO FALL BUT STILL ABOVE BANKFULL STAGE ON THE RIFLE RIVER NEAR STERLING AND TOBACCO RIVER NEAR BEAVERTON. WILL TAKE THROUGH AT LEAST THIS EVENING AND POSSIBLY OVERNIGHT TO GET LEVELS BACK DOWN AGAIN. THUS...CURRENT FLOOD HEADLINES WILL CONTINUES. ADAM TOMORROW NIGHT AND SUNDAY...FRONT TO AGAIN MAKE SOUTHWARD PROGRESS AFTER BUCKLING NORTH AS SURFACE HIGH NOSES INTO THE REGION TOMORROW NIGHT. THIS WILL SCOUR ANY REMNANT CLOUDS (IF THERE ARE ANY BY THIS POINT) AS DRY PUNCH ADVECTS THROUGH THE LAKES...AND BRING A TEMPORARY BREAK FROM PRECIP CHANCES. PATTERN IS PROGRESSIVE SO HIGH WILL SLIDE EAST QUICKLY BY SUNDAY...ALLOWING FOR FRONT TO AGAIN BUCKLE NORTHWARD AS OPENING UPPER WAVE LIFTS FROM THE FOUR CORNERS INTO WESTERN MINNESOTA. DRY AIR INITIALLY QUITE ENTRENCHED AND THUS EXPECT A TIGHT RH GRADIENT TO DEVELOP AS BOUNDARY LIFTS NORTHWARD...CREATING A SHARP CUTOFF TO PRECIP. WHERE THIS LINE WILL EVENTUALLY BE REMAINS IN QUESTION...BUT APPEARS MUCH OF THE CWA WILL REMAIN DRY ON SUNDAY...EXCEPT THE FAR WEST LATE IN THE DAY AS WARM FRONT GETS CLOSER AND SATURATION MAY BE ABLE TO OCCUR. SUNDAY NIGHT INTO MONDAY...THIS PERIOD APPEARS TO HOLD MUCH OF THE ACTION AS WEAKENING BUT STILL POTENT UPPER WAVE LIFTS INTO WESTERN MICHIGAN. AHEAD OF THIS FEATURE...PERSISTENT ISENTROPIC LIFT AND RATHER IMPRESSIVE PUSH OF MOISTURE ADVECTION LIKELY TO SATURATE THINGS BY SUNDAY NIGHT WITH PRECIP INITIALLY FOCUSED ALONG LIFTING WARM FRONT BEFORE ATTENTION TURNS TO APPROACHING UPPER SUPPORT. INCREASING DIFLUENCE AND HELP FROM JET/WARM ADVECTION AND STEEPENING MID LEVEL LAPSE RATES PER APPROACH OF COOL POOL SHOULD SUPPORT A DECENT AREA OF SHOWERS/MAYBE A FEW STORMS PUSHING THROUGH THE AREA SUNDAY NIGHT OR EARLY MONDAY. A RETURN TO QUITE WARM CONDITIONS POSSIBLE MONDAY AFTERNOON AS RESIDUAL FRONT TO THE WEST MAKES ONLY SLOW PROGRESS TO THE EAST WITH AREA FALLING IN THE WARM SECTOR AND H85 TEMPS APPROACHING 11C UNDER SHORTWAVE RIDGING ALOFT. MONDAY NIGHT INTO TUESDAY...MAIN FOCUS IS ON PRECIP CHANCES DURING THIS PERIOD. MAIN FRONTAL BOUNDARY NORTHWEST OF THE AREA ON MONDAY EXPECTED TO GRADUALLY PUSH THROUGH THE AREA ON TUESDAY...THOUGH LIKELY ON A SLOW PACE AS FORCING SHORTWAVE SHEARS OUT AND FRONT RUNS INTO DEEP RIDGING OVER THE SOUTHEAST EXTENDING INTO THE OHIO VALLEY. SETUP APPEARS FAVORABLE FOR PERIODS OF PRECIPITATION WITH SEVERAL WEAK SHORTWAVES LIKELY RIDING UP THE WESTERN PERIPHERY OF UPPER RIDGE...THOUGH LATEST GFS APPEARS OVERDONE AND CONVECTIVELY FED-BACK WITH ITS SPURIOUS SHORTWAVE DEPICTIONS. WITH NEARLY STATIONARY BOUNDARY BECOMING THE FOCUSING MECHANISM AND PLENTY OF DEEP MOISTURE IN PLACE GIVEN PWATS ON THE ORDER OF AN INCH...WILL HAVE CHANCE POPS THROUGH THE PERIOD. TUESDAY NIGHT INTO FRIDAY...THIS PERIOD STILL APPEARS TO BE A NICE STRETCH OF WEATHER. ANY REMNANT PRECIP WILL COME TO AN END TUESDAY EVENING AS LOW/MID LEVELS DRY OUT RAPIDLY WITH EASTWARD ADVANCE OF SFC/UPPER RIDGE. MEANWHILE...STRONG WESTERN CONUS LONGWAVE TROUGH COMING ONSHORE AND ADVANCING INTO THE ROCKIES WILL INCITE DEEP CYCLOGENESIS OVER THE PLAINS...WITH TIGHTENING GRADIENT OVER THE REGION VERSUS DEPARTING SURFACE HIGH. THUS...AFTER A POTENTIALLY CHILLY START WEDNESDAY MORNING...EXPECT A QUICK RECOVERY WITH ENHANCED MIXING PER TIGHTER GRADIENT. APPEARS THIS TIMEFRAME COULD FEATURE THE FIRST FIRE CONCERNS OF THE SEASON AS UPPER RIDGE AXIS BUILDS OVERHEAD WITH DEEP SUBSIDENCE DRYING ENSUING...WHILE SURFACE HIGH NEAR JAMES BAY HOLDS LOW DEW POINTS OVER THE AREA WHILE WINDS COME UP PER TIGHTENING GRADIENT...ESPECIALLY ON THURSDAY. HIGH TEMPERATURES REALLY THE MAIN STORY WITH SPRINGLIKE READINGS RETURNING GIVEN STRONG PUSH OF WARM ADVECTION IN ADVANCE OF PLAINS SYSTEM. HOWEVER...A FEW POTENTIAL ROADBLOCKS REMAIN WHICH COULD RESULT IN COOLER THAN EXPECTED CONDITIONS. APPEARS WARMTH MAY INITIALLY BE SUPPRESSED ON WEDNESDAY AS LIFTING WARM FRONT HAS TROUBLE PUSHING THROUGH THE AREA WITH BLOCKING HIGH PRESENT OVER EASTERN CANADA. HOWEVER...EXPECT PLENTY OF INSOLATION GIVEN DRY POCKET FIRMLY IN PLACE WHICH SHOULD GIVE A BOOST TO READINGS... THOUGH LIKELY ONLY IN THE 50S WITH WARM ADVECTION JUST TAKING HOLD. THURSDAY SHAPING UP TO BE THE WARMEST DAY AS WARM FRONT MIXES NORTHWARD WITH ONSET OF DEEP SOUTHWEST FLOW ALOFT. MIGHT SEE A FEW SHOWERS WITH THE PASSAGE OF THE FRONT PER RENEWED THETA-E ADVECTION AND BRIEF PERIOD OF ISENTROPIC ASCENT ALONG/AHEAD OF THE BOUNDARY... HOWEVER GIVEN EXPECTED STRENGTH OF DEVELOPING SYSTEM TO THE WEST...APPEARS PLAUSIBLE FRONT WILL CLEAR MUCH OF THE CWA...THOUGH EVENTUAL PLACEMENT OBVIOUSLY DIFFICULT TO NAIL DOWN AT THIS TIME. HENCE WILL KEEP HIGHS LOWER 50S FAR NORTH TO AROUND 60 SOUTH...THOUGH COULD EASILY BE MUCH WARMER PENDING PLACEMENT/TIMING OF BOUNDARY. COLD FRONT QUICKLY FOLLOWS LATE THURSDAY AS LOW OCCLUDES OVER THE NORTHERN PLAINS...BRINGING INCREASED CHANCES FOR PRECIP THURSDAY AFTERNOON INTO EARLY FRIDAY. HAVE INCLUDED MENTION OF THUNDER THIS GO AROUND AS ATMOSPHERE SHOULD BE AT LEAST MARGINALLY UNSTABLE WITH PLUME OF DEEP MOISTURE FIRMLY IN PLACE. FORCING ALSO APPEARS RATHER GOOD WITH INCREASING DIFLUENCE ALOFT AS UPPER WAVE OPENS UP AND TRACKS TOWARD THE WESTERN LAKES WITH STRONG FRONT CRUISING EAST INTO THE LAKES. OF COURSE...THIS SYSTEM STILL WELL OFFSHORE AT THIS POINT AND WHILE I DO FORESEE A PERIOD OF MORE ACTIVE WEATHER FOR THE LATTER HALF OF THE WEEK...ALSO EXPECT TIMING CHANGES OVER THE COMING DAYS. LAWRENCE && .AVIATION...ISSUED AT 130 PM. SURFACE HIGH PRESSURE WILL KEEP A VERY DRY AIRMASS WITHIN THE LOW LEVELS IN PLACE THROUGH THE AFTERNOON AND EVENING HOURS...MAINTAINING THE VFR CONDITIONS AT ALL LOCATIONS. HOWEVER...MID-LEVEL MOISTURE WILL CONTINUE TO PRODUCE A SCT-BKN090 DECK...MOSTLY AFFECTING PLN...WITH A MORE SCT SCENARIO AT APN. A SHORTWAVE MOVING OVER THE GREAT PLAINS WILL TRACK TOWARD THE GREAT LAKES OVERNIGHT...AND WILL HELP TO DRAW LOW LEVEL MOISTURE NORTHWARD...AND PRODUCE MVFR CONDITIONS AT ALL TAF SITES LATE OVERNIGHT THROUGH TOMORROW MORNING. STILL SOME QUESTION HOW FAR NORTH THIS LOW LEVEL MOISTURE WILL PENETRATE THE DRY AIR CURRENTLY IN PLACE. MPC && .APX WATCHES/WARNINGS/ADVISORIES...FLOOD WATCH...THROUGH EARLY SATURDAY MORNING...MIZ041-042. FLOOD WARNING...THROUGH 6 PM SATURDAY...MIZ042. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1007 PM EDT FRI MAR 23 2007 .UPDATE...MAIN CONCERN IS FOR THE CLOUD COVER AND ANY RAIN CHANCES FOR THE N LOWER OVERNIGHT. MID CLOUDS HAVE BEEN MAKING THEIR WAY INTO THE SW PORTION OF THE FORECAST AREA WITH MOST OF THE LOWER CLOUDS STAYING SOUTH OF M-55. THE NAM LOOKS TO BE HANDLING THIS SITUATION THE BEST WITH THE TIME-HEIGHT SECTIONS OVER THE TVC SHOWING THAT THE LOWEST CLOUDS WILL PROBABLY STAY SOUTH WITH THE MOISTURE KEEPING THE AT OR ABOVE 3000FT. SO THE MAIN THING WILL BE CLOUDING THE FORECAST TONIGHT FASTER AND ADDING A CHANCE OF RAIN SHOWERS FOR THE OVERNIGHT. LUTZ && .AVIATION...ISSUED 819 PM HAVE BEEN TIMING THE CLOUD COVER THAT WILL AFFECT TVC FIRST AND THEN PLN AND APN. THE TIMING LOOKS CONSISTENT WITH THE NAM AND RUC MODELS AND SUBSEQUENTLY THE ACTUAL TAFS. SO HAVE LEFT THE FIRST 6 HOURS ALONE FOR THE MOST PART AS THE LOWEST CLOUDS LOOK TO STAYING SOUTH OF THE FORECAST AREA. OTHERWISE, THE CLOUDS WILL MOVE OVER THE N LOWER OVERNIGHT AND THEN MOVE OUT BY THE LATE AFTERNOON ON SATURDAY AS THE 500 MB TROUGH MOVES THROUGH THE REGION. LUTZ && .PREV DISCUSSION...ISSUED 349 PM HIGH PRESSURE/DRY AIR REMAINS IN CONTROL ACROSS NRN MICHIGAN THIS AFTERNOON. AREA OF THICKER MID CLOUD ASSOCIATED WITH WEAK SHORT WAVE (PER WATER VAPOR IMAGERY) PASSING THROUGH THE UPPER PENINSULA CONTINUING TO PRODUCE SCT-BKN MID CLOUD OVER THE NRN PORTION OF THE CWA AND WILL CONTINUE TO DO SO INTO THE EVENING PER SATELLITE TRENDS. TO THE SOUTH...ACTIVE BAROCLINIC ZONE DRAPED OVER THE OHIO VALLEY PRODUCING PERSISTENT RAINFALL JUST SOUTH OF THE STATE (MORE ON THAT BELOW). TO THE WEST...STRONGER NRN STREAM SHORT WAVE CROSS THE U.S./CANADIAN BORDER NEAR THE DAKOTAS AND WILL BE PASSING THROUGH THE REGION SATURDAY. TONIGHT THROUGH SATURDAY...12Z MODEL GUIDANCE OFFERING A DIFFERENT SCENARIO OVER THE NEXT 24 HOURS VERSUS PREVIOUS RUNS...SPECIFICALLY IN THEIR HANDLING OF THE WAVY BAROCLINIC ZONE TO THE SOUTH. 12Z NAM/GFS HAVE TRENDED A BIT MORE BULLISH...DRAWING A SUBSTANTIAL AMOUNT OF LOW LEVEL MOISTURE UP INTO NORTHERN MICHIGAN LATER THIS EVENING AND OVERNIGHT WHILE SOME SEMBLANCE OF A WEAK LOW LEVEL CIRCULATION PASSES THROUGH NRN LOWER MICHIGAN. THIS CERTAINLY APPEARS TO BE THE TREND AS VISIBLE SATELLITE IMAGERY REVEALING WALL OF STRATUS MAKING STEADY PROGRESS NORTHWARD THROUGH SRN WISCONSIN AND SRN LOWER MICHIGAN THIS AFTERNOON AND HAVE THUS TRENDED THE FORECAST TOWARD THE CLOUDIER SIDE OF THINGS OVERNIGHT THROUGH SATURDAY MIDDAY. CANNOT RULE OUT THE POSSIBILITIES FOR SOME PRECIP PARTICULARLY SATURDAY MORNING AS NRN STREAM WAVE MOVES THROUGH. BUT NAM/GFS FORECAST SOUNDINGS A BIT SHALLOW WITH THE MOISTURE - PRIMARILY WARMER THAN 0C. IF ANYTHING...CAN SEE SOME DRIZZLE DEVELOPING UP INTO THE HIGHER TERRAIN WITH SOME SEMBLANCE OF AN UPSLOPE FLOW. BUT HAVE KEPT THE FORECAST FOR MOST OF NRN LOWER MICHIGAN DRY FOR NOW. MEANWHILE...AFOREMENTIONED MID LEVEL SHORT WAVE COMING OUT OF THE NRN PLAINS AND THROUGH THE NRN PART OF THE STATE OVERNIGHT THROWS YET ANOTHER WRENCH INTO THE FORECAST. DECENT POCKET OF ASSOCIATED MID LEVEL QG UPWARD FORCING SWEEPING THROUGH THE NRN HALF OF THE STATE LATE OVERNIGHT AND SATURDAY MORNING/COMBINED WITH BETTER MID LEVEL MOISTURE MAY BE ENOUGH TO SQUEEZE OUT SOME LIGHT MEASURABLE RAINFALL ACROSS THE U.P. AND TIP OF THE MITT COUNTIES. SO PLAN IS TO CARRY LOW CHANCE POPS FOR THOSE AREAS OVERNIGHT THROUGH MIDDAY. MAY GET LOCKED INTO THE LOW CLOUD COVER THROUGH MUCH OF THE DAY SATURDAY. HOWEVER...DRIER AIR/RIDGING LOOKING TO BUILD BACK INTO THE REGION LATE IN THE DAY AND SHOULD HOPEFULLY BEGIN TO CLEAR THINGS OUT AS WE GO THROUGH THE AFTERNOON. HYDRO CONCERNS...USGS GAGE READINGS ON THE TOBACCO AND RIFLE RIVERS NOW STARTING TO FALL BUT STILL ABOVE BANKFULL STAGE ON THE RIFLE RIVER NEAR STERLING AND TOBACCO RIVER NEAR BEAVERTON. WILL TAKE THROUGH AT LEAST THIS EVENING AND POSSIBLY OVERNIGHT TO GET LEVELS BACK DOWN AGAIN. THUS...CURRENT FLOOD HEADLINES WILL CONTINUES. ADAM TOMORROW NIGHT AND SUNDAY...FRONT TO AGAIN MAKE SOUTHWARD PROGRESS AFTER BUCKLING NORTH AS SURFACE HIGH NOSES INTO THE REGION TOMORROW NIGHT. THIS WILL SCOUR ANY REMNANT CLOUDS (IF THERE ARE ANY BY THIS POINT) AS DRY PUNCH ADVECTS THROUGH THE LAKES...AND BRING A TEMPORARY BREAK FROM PRECIP CHANCES. PATTERN IS PROGRESSIVE SO HIGH WILL SLIDE EAST QUICKLY BY SUNDAY...ALLOWING FOR FRONT TO AGAIN BUCKLE NORTHWARD AS OPENING UPPER WAVE LIFTS FROM THE FOUR CORNERS INTO WESTERN MINNESOTA. DRY AIR INITIALLY QUITE ENTRENCHED AND THUS EXPECT A TIGHT RH GRADIENT TO DEVELOP AS BOUNDARY LIFTS NORTHWARD...CREATING A SHARP CUTOFF TO PRECIP. WHERE THIS LINE WILL EVENTUALLY BE REMAINS IN QUESTION...BUT APPEARS MUCH OF THE CWA WILL REMAIN DRY ON SUNDAY...EXCEPT THE FAR WEST LATE IN THE DAY AS WARM FRONT GETS CLOSER AND SATURATION MAY BE ABLE TO OCCUR. SUNDAY NIGHT INTO MONDAY...THIS PERIOD APPEARS TO HOLD MUCH OF THE ACTION AS WEAKENING BUT STILL POTENT UPPER WAVE LIFTS INTO WESTERN MICHIGAN. AHEAD OF THIS FEATURE...PERSISTENT ISENTROPIC LIFT AND RATHER IMPRESSIVE PUSH OF MOISTURE ADVECTION LIKELY TO SATURATE THINGS BY SUNDAY NIGHT WITH PRECIP INITIALLY FOCUSED ALONG LIFTING WARM FRONT BEFORE ATTENTION TURNS TO APPROACHING UPPER SUPPORT. INCREASING DIFLUENCE AND HELP FROM JET/WARM ADVECTION AND STEEPENING MID LEVEL LAPSE RATES PER APPROACH OF COOL POOL SHOULD SUPPORT A DECENT AREA OF SHOWERS/MAYBE A FEW STORMS PUSHING THROUGH THE AREA SUNDAY NIGHT OR EARLY MONDAY. A RETURN TO QUITE WARM CONDITIONS POSSIBLE MONDAY AFTERNOON AS RESIDUAL FRONT TO THE WEST MAKES ONLY SLOW PROGRESS TO THE EAST WITH AREA FALLING IN THE WARM SECTOR AND H85 TEMPS APPROACHING 11C UNDER SHORTWAVE RIDGING ALOFT. MONDAY NIGHT INTO TUESDAY...MAIN FOCUS IS ON PRECIP CHANCES DURING THIS PERIOD. MAIN FRONTAL BOUNDARY NORTHWEST OF THE AREA ON MONDAY EXPECTED TO GRADUALLY PUSH THROUGH THE AREA ON TUESDAY...THOUGH LIKELY ON A SLOW PACE AS FORCING SHORTWAVE SHEARS OUT AND FRONT RUNS INTO DEEP RIDGING OVER THE SOUTHEAST EXTENDING INTO THE OHIO VALLEY. SETUP APPEARS FAVORABLE FOR PERIODS OF PRECIPITATION WITH SEVERAL WEAK SHORTWAVES LIKELY RIDING UP THE WESTERN PERIPHERY OF UPPER RIDGE...THOUGH LATEST GFS APPEARS OVERDONE AND CONVECTIVELY FED-BACK WITH ITS SPURIOUS SHORTWAVE DEPICTIONS. WITH NEARLY STATIONARY BOUNDARY BECOMING THE FOCUSING MECHANISM AND PLENTY OF DEEP MOISTURE IN PLACE GIVEN PWATS ON THE ORDER OF AN INCH...WILL HAVE CHANCE POPS THROUGH THE PERIOD. TUESDAY NIGHT INTO FRIDAY...THIS PERIOD STILL APPEARS TO BE A NICE STRETCH OF WEATHER. ANY REMNANT PRECIP WILL COME TO AN END TUESDAY EVENING AS LOW/MID LEVELS DRY OUT RAPIDLY WITH EASTWARD ADVANCE OF SFC/UPPER RIDGE. MEANWHILE...STRONG WESTERN CONUS LONGWAVE TROUGH COMING ONSHORE AND ADVANCING INTO THE ROCKIES WILL INCITE DEEP CYCLOGENESIS OVER THE PLAINS...WITH TIGHTENING GRADIENT OVER THE REGION VERSUS DEPARTING SURFACE HIGH. THUS...AFTER A POTENTIALLY CHILLY START WEDNESDAY MORNING...EXPECT A QUICK RECOVERY WITH ENHANCED MIXING PER TIGHTER GRADIENT. APPEARS THIS TIMEFRAME COULD FEATURE THE FIRST FIRE CONCERNS OF THE SEASON AS UPPER RIDGE AXIS BUILDS OVERHEAD WITH DEEP SUBSIDENCE DRYING ENSUING...WHILE SURFACE HIGH NEAR JAMES BAY HOLDS LOW DEW POINTS OVER THE AREA WHILE WINDS COME UP PER TIGHTENING GRADIENT...ESPECIALLY ON THURSDAY. HIGH TEMPERATURES REALLY THE MAIN STORY WITH SPRINGLIKE READINGS RETURNING GIVEN STRONG PUSH OF WARM ADVECTION IN ADVANCE OF PLAINS SYSTEM. HOWEVER...A FEW POTENTIAL ROADBLOCKS REMAIN WHICH COULD RESULT IN COOLER THAN EXPECTED CONDITIONS. APPEARS WARMTH MAY INITIALLY BE SUPPRESSED ON WEDNESDAY AS LIFTING WARM FRONT HAS TROUBLE PUSHING THROUGH THE AREA WITH BLOCKING HIGH PRESENT OVER EASTERN CANADA. HOWEVER...EXPECT PLENTY OF INSOLATION GIVEN DRY POCKET FIRMLY IN PLACE WHICH SHOULD GIVE A BOOST TO READINGS... THOUGH LIKELY ONLY IN THE 50S WITH WARM ADVECTION JUST TAKING HOLD. THURSDAY SHAPING UP TO BE THE WARMEST DAY AS WARM FRONT MIXES NORTHWARD WITH ONSET OF DEEP SOUTHWEST FLOW ALOFT. MIGHT SEE A FEW SHOWERS WITH THE PASSAGE OF THE FRONT PER RENEWED THETA-E ADVECTION AND BRIEF PERIOD OF ISENTROPIC ASCENT ALONG/AHEAD OF THE BOUNDARY... HOWEVER GIVEN EXPECTED STRENGTH OF DEVELOPING SYSTEM TO THE WEST...APPEARS PLAUSIBLE FRONT WILL CLEAR MUCH OF THE CWA...THOUGH EVENTUAL PLACEMENT OBVIOUSLY DIFFICULT TO NAIL DOWN AT THIS TIME. HENCE WILL KEEP HIGHS LOWER 50S FAR NORTH TO AROUND 60 SOUTH...THOUGH COULD EASILY BE MUCH WARMER PENDING PLACEMENT/TIMING OF BOUNDARY. COLD FRONT QUICKLY FOLLOWS LATE THURSDAY AS LOW OCCLUDES OVER THE NORTHERN PLAINS...BRINGING INCREASED CHANCES FOR PRECIP THURSDAY AFTERNOON INTO EARLY FRIDAY. HAVE INCLUDED MENTION OF THUNDER THIS GO AROUND AS ATMOSPHERE SHOULD BE AT LEAST MARGINALLY UNSTABLE WITH PLUME OF DEEP MOISTURE FIRMLY IN PLACE. FORCING ALSO APPEARS RATHER GOOD WITH INCREASING DIFLUENCE ALOFT AS UPPER WAVE OPENS UP AND TRACKS TOWARD THE WESTERN LAKES WITH STRONG FRONT CRUISING EAST INTO THE LAKES. OF COURSE...THIS SYSTEM STILL WELL OFFSHORE AT THIS POINT AND WHILE I DO FORESEE A PERIOD OF MORE ACTIVE WEATHER FOR THE LATTER HALF OF THE WEEK...ALSO EXPECT TIMING CHANGES OVER THE COMING DAYS. LAWRENCE && .AVIATION...ISSUED AT 130 PM. SURFACE HIGH PRESSURE WILL KEEP A VERY DRY AIRMASS WITHIN THE LOW LEVELS IN PLACE THROUGH THE AFTERNOON AND EVENING HOURS...MAINTAINING THE VFR CONDITIONS AT ALL LOCATIONS. HOWEVER...MID-LEVEL MOISTURE WILL CONTINUE TO PRODUCE A SCT-BKN090 DECK...MOSTLY AFFECTING PLN...WITH A MORE SCT SCENARIO AT APN. A SHORTWAVE MOVING OVER THE GREAT PLAINS WILL TRACK TOWARD THE GREAT LAKES OVERNIGHT...AND WILL HELP TO DRAW LOW LEVEL MOISTURE NORTHWARD...AND PRODUCE MVFR CONDITIONS AT ALL TAF SITES LATE OVERNIGHT THROUGH TOMORROW MORNING. STILL SOME QUESTION HOW FAR NORTH THIS LOW LEVEL MOISTURE WILL PENETRATE THE DRY AIR CURRENTLY IN PLACE. MPC && .APX WATCHES/WARNINGS/ADVISORIES...FLOOD WATCH...THROUGH EARLY SATURDAY MORNING...MIZ041-042. FLOOD WARNING...THROUGH MIDNIGHT...MIZ042. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 819 PM EDT FRI MAR 23 2007 .AVIATION...HAVE BEEN TIMING THE CLOUD COVER THAT WILL AFFECT TVC FIRST AND THEN PLN AND APN. THE TIMING LOOKS CONSISTENT WITH THE NAM AND RUC MODELS AND SUBSEQUENTLY THE ACTUAL TAFS. SO HAVE LEFT THE FIRST 6 HOURS ALONE FOR THE MOST PART AS THE LOWEST CLOUDS LOOK TO STAYING SOUTH OF THE FORECAST AREA. OTHERWISE, THE CLOUDS WILL MOVE OVER THE N LOWER OVERNIGHT AND THEN MOVE OUT BY THE LATE AFTERNOON ON SATURDAY AS THE 500 MB TROUGH MOVES THROUGH THE REGION. LUTZ && .PREV DISCUSSION...ISSUED 349 PM HIGH PRESSURE/DRY AIR REMAINS IN CONTROL ACROSS NRN MICHIGAN THIS AFTERNOON. AREA OF THICKER MID CLOUD ASSOCIATED WITH WEAK SHORT WAVE (PER WATER VAPOR IMAGERY) PASSING THROUGH THE UPPER PENINSULA CONTINUING TO PRODUCE SCT-BKN MID CLOUD OVER THE NRN PORTION OF THE CWA AND WILL CONTINUE TO DO SO INTO THE EVENING PER SATELLITE TRENDS. TO THE SOUTH...ACTIVE BAROCLINIC ZONE DRAPED OVER THE OHIO VALLEY PRODUCING PERSISTENT RAINFALL JUST SOUTH OF THE STATE (MORE ON THAT BELOW). TO THE WEST...STRONGER NRN STREAM SHORT WAVE CROSS THE U.S./CANADIAN BORDER NEAR THE DAKOTAS AND WILL BE PASSING THROUGH THE REGION SATURDAY. TONIGHT THROUGH SATURDAY...12Z MODEL GUIDANCE OFFERING A DIFFERENT SCENARIO OVER THE NEXT 24 HOURS VERSUS PREVIOUS RUNS...SPECIFICALLY IN THEIR HANDLING OF THE WAVY BAROCLINIC ZONE TO THE SOUTH. 12Z NAM/GFS HAVE TRENDED A BIT MORE BULLISH...DRAWING A SUBSTANTIAL AMOUNT OF LOW LEVEL MOISTURE UP INTO NORTHERN MICHIGAN LATER THIS EVENING AND OVERNIGHT WHILE SOME SEMBLANCE OF A WEAK LOW LEVEL CIRCULATION PASSES THROUGH NRN LOWER MICHIGAN. THIS CERTAINLY APPEARS TO BE THE TREND AS VISIBLE SATELLITE IMAGERY REVEALING WALL OF STRATUS MAKING STEADY PROGRESS NORTHWARD THROUGH SRN WISCONSIN AND SRN LOWER MICHIGAN THIS AFTERNOON AND HAVE THUS TRENDED THE FORECAST TOWARD THE CLOUDIER SIDE OF THINGS OVERNIGHT THROUGH SATURDAY MIDDAY. CANNOT RULE OUT THE POSSIBILITIES FOR SOME PRECIP PARTICULARLY SATURDAY MORNING AS NRN STREAM WAVE MOVES THROUGH. BUT NAM/GFS FORECAST SOUNDINGS A BIT SHALLOW WITH THE MOISTURE - PRIMARILY WARMER THAN 0C. IF ANYTHING...CAN SEE SOME DRIZZLE DEVELOPING UP INTO THE HIGHER TERRAIN WITH SOME SEMBLANCE OF AN UPSLOPE FLOW. BUT HAVE KEPT THE FORECAST FOR MOST OF NRN LOWER MICHIGAN DRY FOR NOW. MEANWHILE...AFOREMENTIONED MID LEVEL SHORT WAVE COMING OUT OF THE NRN PLAINS AND THROUGH THE NRN PART OF THE STATE OVERNIGHT THROWS YET ANOTHER WRENCH INTO THE FORECAST. DECENT POCKET OF ASSOCIATED MID LEVEL QG UPWARD FORCING SWEEPING THROUGH THE NRN HALF OF THE STATE LATE OVERNIGHT AND SATURDAY MORNING/COMBINED WITH BETTER MID LEVEL MOISTURE MAY BE ENOUGH TO SQUEEZE OUT SOME LIGHT MEASURABLE RAINFALL ACROSS THE U.P. AND TIP OF THE MITT COUNTIES. SO PLAN IS TO CARRY LOW CHANCE POPS FOR THOSE AREAS OVERNIGHT THROUGH MIDDAY. MAY GET LOCKED INTO THE LOW CLOUD COVER THROUGH MUCH OF THE DAY SATURDAY. HOWEVER...DRIER AIR/RIDGING LOOKING TO BUILD BACK INTO THE REGION LATE IN THE DAY AND SHOULD HOPEFULLY BEGIN TO CLEAR THINGS OUT AS WE GO THROUGH THE AFTERNOON. HYDRO CONCERNS...USGS GAGE READINGS ON THE TOBACCO AND RIFLE RIVERS NOW STARTING TO FALL BUT STILL ABOVE BANKFULL STAGE ON THE RIFLE RIVER NEAR STERLING AND TOBACCO RIVER NEAR BEAVERTON. WILL TAKE THROUGH AT LEAST THIS EVENING AND POSSIBLY OVERNIGHT TO GET LEVELS BACK DOWN AGAIN. THUS...CURRENT FLOOD HEADLINES WILL CONTINUES. ADAM TOMORROW NIGHT AND SUNDAY...FRONT TO AGAIN MAKE SOUTHWARD PROGRESS AFTER BUCKLING NORTH AS SURFACE HIGH NOSES INTO THE REGION TOMORROW NIGHT. THIS WILL SCOUR ANY REMNANT CLOUDS (IF THERE ARE ANY BY THIS POINT) AS DRY PUNCH ADVECTS THROUGH THE LAKES...AND BRING A TEMPORARY BREAK FROM PRECIP CHANCES. PATTERN IS PROGRESSIVE SO HIGH WILL SLIDE EAST QUICKLY BY SUNDAY...ALLOWING FOR FRONT TO AGAIN BUCKLE NORTHWARD AS OPENING UPPER WAVE LIFTS FROM THE FOUR CORNERS INTO WESTERN MINNESOTA. DRY AIR INITIALLY QUITE ENTRENCHED AND THUS EXPECT A TIGHT RH GRADIENT TO DEVELOP AS BOUNDARY LIFTS NORTHWARD...CREATING A SHARP CUTOFF TO PRECIP. WHERE THIS LINE WILL EVENTUALLY BE REMAINS IN QUESTION...BUT APPEARS MUCH OF THE CWA WILL REMAIN DRY ON SUNDAY...EXCEPT THE FAR WEST LATE IN THE DAY AS WARM FRONT GETS CLOSER AND SATURATION MAY BE ABLE TO OCCUR. SUNDAY NIGHT INTO MONDAY...THIS PERIOD APPEARS TO HOLD MUCH OF THE ACTION AS WEAKENING BUT STILL POTENT UPPER WAVE LIFTS INTO WESTERN MICHIGAN. AHEAD OF THIS FEATURE...PERSISTENT ISENTROPIC LIFT AND RATHER IMPRESSIVE PUSH OF MOISTURE ADVECTION LIKELY TO SATURATE THINGS BY SUNDAY NIGHT WITH PRECIP INITIALLY FOCUSED ALONG LIFTING WARM FRONT BEFORE ATTENTION TURNS TO APPROACHING UPPER SUPPORT. INCREASING DIFLUENCE AND HELP FROM JET/WARM ADVECTION AND STEEPENING MID LEVEL LAPSE RATES PER APPROACH OF COOL POOL SHOULD SUPPORT A DECENT AREA OF SHOWERS/MAYBE A FEW STORMS PUSHING THROUGH THE AREA SUNDAY NIGHT OR EARLY MONDAY. A RETURN TO QUITE WARM CONDITIONS POSSIBLE MONDAY AFTERNOON AS RESIDUAL FRONT TO THE WEST MAKES ONLY SLOW PROGRESS TO THE EAST WITH AREA FALLING IN THE WARM SECTOR AND H85 TEMPS APPROACHING 11C UNDER SHORTWAVE RIDGING ALOFT. MONDAY NIGHT INTO TUESDAY...MAIN FOCUS IS ON PRECIP CHANCES DURING THIS PERIOD. MAIN FRONTAL BOUNDARY NORTHWEST OF THE AREA ON MONDAY EXPECTED TO GRADUALLY PUSH THROUGH THE AREA ON TUESDAY...THOUGH LIKELY ON A SLOW PACE AS FORCING SHORTWAVE SHEARS OUT AND FRONT RUNS INTO DEEP RIDGING OVER THE SOUTHEAST EXTENDING INTO THE OHIO VALLEY. SETUP APPEARS FAVORABLE FOR PERIODS OF PRECIPITATION WITH SEVERAL WEAK SHORTWAVES LIKELY RIDING UP THE WESTERN PERIPHERY OF UPPER RIDGE...THOUGH LATEST GFS APPEARS OVERDONE AND CONVECTIVELY FED-BACK WITH ITS SPURIOUS SHORTWAVE DEPICTIONS. WITH NEARLY STATIONARY BOUNDARY BECOMING THE FOCUSING MECHANISM AND PLENTY OF DEEP MOISTURE IN PLACE GIVEN PWATS ON THE ORDER OF AN INCH...WILL HAVE CHANCE POPS THROUGH THE PERIOD. TUESDAY NIGHT INTO FRIDAY...THIS PERIOD STILL APPEARS TO BE A NICE STRETCH OF WEATHER. ANY REMNANT PRECIP WILL COME TO AN END TUESDAY EVENING AS LOW/MID LEVELS DRY OUT RAPIDLY WITH EASTWARD ADVANCE OF SFC/UPPER RIDGE. MEANWHILE...STRONG WESTERN CONUS LONGWAVE TROUGH COMING ONSHORE AND ADVANCING INTO THE ROCKIES WILL INCITE DEEP CYCLOGENESIS OVER THE PLAINS...WITH TIGHTENING GRADIENT OVER THE REGION VERSUS DEPARTING SURFACE HIGH. THUS...AFTER A POTENTIALLY CHILLY START WEDNESDAY MORNING...EXPECT A QUICK RECOVERY WITH ENHANCED MIXING PER TIGHTER GRADIENT. APPEARS THIS TIMEFRAME COULD FEATURE THE FIRST FIRE CONCERNS OF THE SEASON AS UPPER RIDGE AXIS BUILDS OVERHEAD WITH DEEP SUBSIDENCE DRYING ENSUING...WHILE SURFACE HIGH NEAR JAMES BAY HOLDS LOW DEW POINTS OVER THE AREA WHILE WINDS COME UP PER TIGHTENING GRADIENT...ESPECIALLY ON THURSDAY. HIGH TEMPERATURES REALLY THE MAIN STORY WITH SPRINGLIKE READINGS RETURNING GIVEN STRONG PUSH OF WARM ADVECTION IN ADVANCE OF PLAINS SYSTEM. HOWEVER...A FEW POTENTIAL ROADBLOCKS REMAIN WHICH COULD RESULT IN COOLER THAN EXPECTED CONDITIONS. APPEARS WARMTH MAY INITIALLY BE SUPPRESSED ON WEDNESDAY AS LIFTING WARM FRONT HAS TROUBLE PUSHING THROUGH THE AREA WITH BLOCKING HIGH PRESENT OVER EASTERN CANADA. HOWEVER...EXPECT PLENTY OF INSOLATION GIVEN DRY POCKET FIRMLY IN PLACE WHICH SHOULD GIVE A BOOST TO READINGS... THOUGH LIKELY ONLY IN THE 50S WITH WARM ADVECTION JUST TAKING HOLD. THURSDAY SHAPING UP TO BE THE WARMEST DAY AS WARM FRONT MIXES NORTHWARD WITH ONSET OF DEEP SOUTHWEST FLOW ALOFT. MIGHT SEE A FEW SHOWERS WITH THE PASSAGE OF THE FRONT PER RENEWED THETA-E ADVECTION AND BRIEF PERIOD OF ISENTROPIC ASCENT ALONG/AHEAD OF THE BOUNDARY... HOWEVER GIVEN EXPECTED STRENGTH OF DEVELOPING SYSTEM TO THE WEST...APPEARS PLAUSIBLE FRONT WILL CLEAR MUCH OF THE CWA...THOUGH EVENTUAL PLACEMENT OBVIOUSLY DIFFICULT TO NAIL DOWN AT THIS TIME. HENCE WILL KEEP HIGHS LOWER 50S FAR NORTH TO AROUND 60 SOUTH...THOUGH COULD EASILY BE MUCH WARMER PENDING PLACEMENT/TIMING OF BOUNDARY. COLD FRONT QUICKLY FOLLOWS LATE THURSDAY AS LOW OCCLUDES OVER THE NORTHERN PLAINS...BRINGING INCREASED CHANCES FOR PRECIP THURSDAY AFTERNOON INTO EARLY FRIDAY. HAVE INCLUDED MENTION OF THUNDER THIS GO AROUND AS ATMOSPHERE SHOULD BE AT LEAST MARGINALLY UNSTABLE WITH PLUME OF DEEP MOISTURE FIRMLY IN PLACE. FORCING ALSO APPEARS RATHER GOOD WITH INCREASING DIFLUENCE ALOFT AS UPPER WAVE OPENS UP AND TRACKS TOWARD THE WESTERN LAKES WITH STRONG FRONT CRUISING EAST INTO THE LAKES. OF COURSE...THIS SYSTEM STILL WELL OFFSHORE AT THIS POINT AND WHILE I DO FORESEE A PERIOD OF MORE ACTIVE WEATHER FOR THE LATTER HALF OF THE WEEK...ALSO EXPECT TIMING CHANGES OVER THE COMING DAYS. LAWRENCE && .AVIATION...ISSUED AT 130 PM. SURFACE HIGH PRESSURE WILL KEEP A VERY DRY AIRMASS WITHIN THE LOW LEVELS IN PLACE THROUGH THE AFTERNOON AND EVENING HOURS...MAINTAINING THE VFR CONDITIONS AT ALL LOCATIONS. HOWEVER...MID-LEVEL MOISTURE WILL CONTINUE TO PRODUCE A SCT-BKN090 DECK...MOSTLY AFFECTING PLN...WITH A MORE SCT SCENARIO AT APN. A SHORTWAVE MOVING OVER THE GREAT PLAINS WILL TRACK TOWARD THE GREAT LAKES OVERNIGHT...AND WILL HELP TO DRAW LOW LEVEL MOISTURE NORTHWARD...AND PRODUCE MVFR CONDITIONS AT ALL TAF SITES LATE OVERNIGHT THROUGH TOMORROW MORNING. STILL SOME QUESTION HOW FAR NORTH THIS LOW LEVEL MOISTURE WILL PENETRATE THE DRY AIR CURRENTLY IN PLACE. MPC && .APX WATCHES/WARNINGS/ADVISORIES...FLOOD WATCH...THROUGH EARLY SATURDAY MORNING...MIZ041-042. FLOOD WARNING...THROUGH MIDNIGHT...MIZ042. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 415 PM EDT FRI MAR 23 2007 .DISCUSSION... .SHORT TERM (TONIGHT AND SAT)... WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW NEARLY ZONAL FLOW ACROSS THE NRN CONUS/SRN CANADA. IN THIS FAST FLOW...SHORTWAVE OF INTEREST IN THE SHORT TERM IS OVER SRN SASKATCHEWAN/ERN MT/WRN ND. RADARS SHOW DECENT COVERAGE OF ECHOES ACROSS ND/SRN MANITOBA ASSOCIATED WITH THIS SHORTWAVE...AND THERE HAVE BEEN A FEW OBS THAT HAVE INDICATED -SHRA IN NRN ND/SE SASKATCHEWAN/SRN MANITOBA TODAY. WELL TO THE W... SHORTWAVE THAT DROPPED OUT OF THE WESTERLIES 2-3 DAYS AGO OVER THE W COAST AND BECAME A MID LEVEL LOW IS NOW CENTERED JUST S OF AZ. THIS SYSTEM WILL BE OF INTEREST TO FCST HERE LATE IN THE UPCOMING WEEKEND AS IT GETS KICKED NE BY NEXT TROF APPROACHING THE W COAST. MODELS ARE IN GOOD AGREEMENT STRENGTHENING UPSTREAM SHORTWAVE A BIT AS IT MOVES TO UPPER MI/LAKE SUPERIOR SAT MORNING. WITH AIRMASS AHEAD OF APPROACHING SHORTWAVE RELATIVELY DRY PER 12Z KBIS/KINL SOUNDINGS...IT BECOMES THE TYPICAL QUESTION OF WHETHER FORCING WILL BE SUFFICIENT TO MOISTEN THE DRY COLUMN TO ALLOW PCPN TO REACH THE SFC. BEST COMBINATION OF LOW CONDENSATION PRES DEFICITS AND ASCENT ON THE 290K AND 295K SURFACES PASSES ACROSS THE NRN FCST AREA...BUT ANOTHER AREA OF MOIST ASCENT DEVELOPS OVER THE SE AND ERN FCST AREA AS WELL. THE NRN AREA WOULD APPEAR TO BE MORE LIKELY TO SEE PCPN AS IT WILL BE ON THE CYCLONIC SIDE OF STRENGTHENING JET ASSOCIATED WITH SHORTWAVE. TOUGH TO SAY WHETHER FORCING IS SUFFICIENT TO OVERCOME THE DRY AIR...BUT GIVEN MODEL TRENDS FOR THIS SHORTWAVE TO BE STRONGER...WILL INTRODUCE LOW CHC POPS ACROSS THE N TONIGHT. NAM/GFS FCST SOUNDINGS SUGGEST PTYPE WILL BE LIQUID...AND SFC TEMPS SHOULD STAY JUST ABOVE FREEZING TO PREVENT FZRA. OVER THE ERN FCST AREA...MODELS SUGGEST THAT THE NRN EXTENT OF THE DEEP MOISTURE TO THE S MAY SLIP INTO THAT AREA (NOTE SATURATED PROFILE ON 12Z KDVN SOUNDING). WILL THUS ALSO INTRODUCE CHC POPS OVER THE E AS WELL. WILL LINGER CHC POPS OVER THE NCNTRL/E EARLY SAT. OTHERWISE...WITH MODELS INDICATING AGGRESSIVE DRYING THRU MOST OF THE COLUMN SAT IN THE WAKE OF SHORTWAVE...WOULD EXPECT SKIES TO CLEAR OUT NICELY FROM W TO E DURING THE DAY. AS WEAK HIGH PRES SLIDES ACROSS THE AREA DURING THE AFTN...LAKE BREEZES SHOULD BE THE RULE BY MID/LATE AFTN NEAR LAKE SUPERIOR AND LAKE MICHIGAN. MIXING TO 850-800MB ON FCST SOUNDINGS YIELDS HIGHS IN THE MID/UPPER 50S IN THE INTERIOR. .LONG TERM(SAT NIGHT THROUGH THU) MAIN FCST CONCERNS ARE SHRA/TSRA POTENTIAL LATE SUN INTO MON AND AGAIN BY WED/THU. SAT NIGHT...WITH THE SFC RDG...MOSTLY CLEAR SKIES AND VERY DRY AIRMASS IN PLACE OVER THE AREA(PWAT AOB 0.25 INCH) AND LIGHT WINDS FOR MOST OF THE NIGHT...FAVORABLE RADIATIONAL COOLING CONDITIONS SHOULD ALLOW TEMPS TO DROP INTO THE MID TO UPPER 20S INLAND...A BIT BLO GUIDANCE. HOWEVER...SOME INCREASE IN MID/HIGH CLOUDS AND SE DOWNSLOPE WINDS LATE FAR WEST COULD BRING CLIMBING TEMPS BEFORE SUNRISE. SUN INTO SUN NIGHT...MDLS ARE IN GENERAL AGREEMENT IN LIFTING A SHRTWV...REMNANTS OF THE BAHA/SW US CLOSED LOW...INTO THE WRN GREAT LAKES. THE UKMET WAS SLOWER/STRONGER WITH THE SYSTEM THAN THE GFS AND THE WEAKER/FASTER CANADIAN GLOBAL GEM. FCST GENERALLY LEANED TOWARD THE GFS. INITIAL BATCH OF SHRA/TSRA COULD DEVELOP WITH STRONG WAA AS THE 925-850 MB THETA-E RDG ARC INTO W UPR MI AND SPREAD E LATE. OTHERWISE...THE MAIN FORCING MOVES IN TOWARD 06Z/MON. EVEN THOUGH SHRTWV PATH WOULD SEEM TO FAVOR THE WRN CWA...DECENT 700-300 MB QVECTOR CONV SPREADS ACRS UPPER MI...SUPPORTING GOING LIKELY POPS SUN NIGHT. WITH THE AMPLIFYING PATTERN...STRONG SRLY FLOW(900-850 MB WINDS AOA 40 KT) BRINGING GULF MOISTURE INTO THE AREA MAY PUSH 900-850 MB DEWPOINTS INTO THE 10C-12C RANGE. 900 MB ELEVATED CAPE INTO THE 300-500 J/KG RANGE WILL DECENT CHANCE FOR TSTMS. EVEN WITH SOME BRIEF HEAVY DOWNPOURS POSSIBLE...THE PROGRESSIVE SYSTEM SHOULD LIMIT GENERAL PCPN AMOUNTS TO LESS THAN AN A HALF INCH. MON...EXPECT SHRA/TSRA TO END OVER THE WEST EARLY AND E BY AFTERNOON AS THE SFC TROF MOVES THROUGH AND SHRTWV RDGING/QVECTOR DIV BUILD IN. SOME SUNSHINE WITH WRLY FLOW AND 900-925 MB TEMPS FCST NEAR 10C SHOULD ALLOW TEMPS TO CLIMB TO AROUND 60 OR THE LOW 60S...CLOSE TO RECORD HIGHS. FOR NOW...KEPT TEMPS FAIRLY CONSERVATIVE...AT OR SLIGHTLY ABOVE GUIDANCE BUT WOULD NOT BE SURPRISED IF READINGS ADJUSTED UPWARD LATER IF A DECENT AMOUNT OF SUNSHINE DEVELOPS. TUE-FRI...MDLS SUGGEST ANOTHER WRN CONUS TROF WILL MOVE TOWARD THE CNTRL CONUS AND GREAT LAKES. SIGNIFICANT DIFFERENCES DEVELOP THOUGH BY LATE IN THE WEEK IN HANDLING THE TROF. THE 06Z/12Z GFS AND ENSEMBLE ARE MORE PROGRESSIVE IN BRINGING A SHRTWV AND SFC TROF/FRONT THROUGH THE UPPER GREAT LAKES EVEN AS THE MID LEVEL LOW LINGERS TO THE NW. THE ECMWF KEEPS THE TROF TO THE WEST. EVEN WITH THE LARGE UNCERTAINTY...SHRA/TSRA CHANCES STILL SEEM WARRANTED GIVEN POTENTIAL FOR THE FRONT TO MOVE IN WITH DECENT MOISTURE INFLOW AHEAD OF THE SYSTEM. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ROLFSON(SHORT TERM) JLB(LONG TERM) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1100 AM EDT FRI MAR 23 2007 .UPDATE... MID CLOUDS CONTINUE TO LINGER LATE THIS MORNING OVER THE ERN FCST AREA...AND NEW CLOUD DEVELOPMENT IS OCCURRING OVER NCNTRL UPPER MI. CLOUDS ARE DEVELOPING IN AN AREA OF PERSISTENT ISENTROPIC ASCENT AS VIEWED ON 290K SFC (ROUGHLY 750-800MB) PER 12Z RUC. ASCENT SLACKENS DURING THE AFTN...SO CLOUDS SHOULD TEND TO THIN OUT SOME LATER IN THE AFTN. AS FOR TEMPS...12Z KINL/KGRB SOUNDINGS AND MORNING TAMDAR SOUNDING FROM KSAW SUPPORT RAISING HIGH TEMPS. KINL/KGRB SOUNDINGS YIELD HIGHS IN THE MID 50S TO AROUND 60F IF MIXED LAYER BUILDS TO 850MB WHILE KSAW SOUNDING SUPPORTS HIGHS IN THE LWR 50S. RAISED HIGHS TO THE LWR END OF THOSE VALUES GIVEN SOME CLOUD COVER. TEMPS WILL BE CONSIDERABLE COOLER NEAR LAKE MICHIGAN UNDER LIGHT SRLY FLOW...AND THE COOLING SHOULD EXTEND ACROSS ALL OF THE ERN FCST AREA. LAKE BREEZE SHOULD DEVELOP OFF LAKE SUPERIOR EXCEPT FOR AREAS E OF MARQUETTE AS SRLY FLOW SHOULD BE SUFFICIENT THRU THE AFTN TO PREVENT DEVELOPMENT THERE. && .PREV DISCUSSION (ISSUED AT 530 AM EDT)... MAIN FCST CONCERNS IN SHORT TERM ARE CLOUDS/TEMPS THEN FOCUS WILL BE ON TIMING OF NEXT CHC OF RAIN/THUNDERSTORMS FOR SUN AFTERNOON. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW ZONAL FLOW ACROSS THE NRN CONUS/SRN CANADA. ONE SHORTWAVE IS MOVING THROUGH THE UPR GREAT LAKES EARLY THIS MORNING WHILE ANOTHER IS UPSTREAM OVER SRN ALBERTA. SHORTWAVE MOVING THROUGH UPR GREAT LAKES PRODUCED A FEW FLURRIES THIS MORNING NORTH OF LAKE SUPERIOR IN AREA OF WEAK Q-VECT CONV AND ISENTROPIC ASCENT. MODEL SNDGS CONSISTENT IN SHOWING LINGERING MOISTURE AROUND 850 MB IN WAKE OF SHORTWAVE SO KEPT IN A BIT MORE CLOUD COVER TODAY IN ANTICIPATION OF STRATOCU DEVELOPING DURING THE DAY. MIXING TO 850-800MB ON FCST SOUNDINGS YIELDS HIGHS IN THE LOW/MID 50S OVER THE WRN INTERIOR. SRLY FLOW WILL KEEP TEMPS MUCH COOLER OVER THE ERN FCST AREA NEAR AND DOWNWIND OF LAKE MICHIGAN. LOCAL COOLING SHOULD ALSO OCCUR NEAR LAKE SUPERIOR OVER THE W AND NCNTRL AREAS MID/LATE AFTN WHERE BOUNDARY LAYER WINDS WILL BE LIGHTER. FROM MUNISING EWD...SRLY FLOW MAY STRONG ENOUGH 10-15 KT TO SUPRESS LAKE BREEZE DEVELOPMENT. NEXT SHORTWAVE FROM ALBERTA IS DUE TO MOVE INTO THE UPR GREAT LAKES LATE FRI NIGHT AND SAT. UPR DIV IN RRQ OF 100 KT 3H JET SHOULD PRODUCE SOME MID CLOUDS PER MODEL SNDGS BUT OTHERWISE MODEL SNDGS LOOK PRETTY DRY AT LOW LEVELS. WEAK PRES GRADIENTS WITH SFC HIGH OVERHEAD WILL ALLOW FOR LAKE BREEZES TO DEVELOP SAT OFF BOTH LAKES SUPERIOR AND MICHIGAN...KEEPING TEMPS COOLER (40S) ALONG LAKESHORE AREAS. MIXING TO AROUND 850 MB OVER THE WESTERN INTERIOR WILL ALLOW MAX TEMPS TO REACH NEAR TO MID 50S. SAT NIGHT...INFLUENCE OF SFC HIGH JUST TO THE NE OF LAKE SUPERIOR WILL ALLOW FOR LIGHT WIND AND GENERALLY CLEAR TO PARTLY CLOUDY SKIES. EXPECT LOWS TO REACH INTO THE 20S OVER THE INTERIOR...CLOSER TO COOLER GFS MOS GUIDANCE. MODELS STILL IN GOOD AGREEMENT SHOWING UPR LOW EJECTING OUT OF THE PLAINS AND INTO THE UPR GREAT LAKES SUN NIGHT INTO MON. AN INCREASING RIBBON OF MOISTURE/ISENTROPIC ASCENT ON THE 300K SFC... A 40KT H85 JET...AND PWATS AROUND AN INCH ARE MAIN TRIGGERS FOR SHOWERS LATE SUN INTO SUN NIGHT. NEG 850-500 MB THETA-E LAPSE RATES COULD ALSO RESULT IN THUNDER. BUMPED UP POPS TO LIKELY SUN NIGHT WITH ARRIVAL OF SFC WARM FRONT AND UPR TROUGH. DEPARTURE OF SHORTWAVE AND ASSOC SFC TROF/WARM FRONT SHOULD TAPER OFF RAIN CHCS BY MON AFTERNOON. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ROLFSON (UPDATE) VOSS (PREV DISCUSSION) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 530 AM EDT FRI MAR 23 2007 .DISCUSSION... MAIN FCST CONCERNS IN SHORT TERM ARE CLOUDS/TEMPS THEN FOCUS WILL BE ON TIMING OF NEXT CHC OF RAIN/THUNDERSTORMS FOR SUN AFTERNOON. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW ZONAL FLOW ACROSS THE NRN CONUS/SRN CANADA. ONE SHORTWAVE IS MOVING THROUGH THE UPR GREAT LAKES EARLY THIS MORNING WHILE ANOTHER IS UPSTREAM OVER SRN ALBERTA. SHORTWAVE MOVING THROUGH UPR GREAT LAKES PRODUCED A FEW FLURRIES THIS MORNING NORTH OF LAKE SUPERIOR IN AREA OF WEAK Q-VECT CONV AND ISENTROPIC ASCENT. MODEL SNDGS CONSISTENT IN SHOWING LINGERING MOISTURE AROUND 850 MB IN WAKE OF SHORTWAVE SO KEPT IN A BIT MORE CLOUD COVER TODAY IN ANTICIPATION OF STRATOCU DEVELOPING DURING THE DAY. MIXING TO 850-800MB ON FCST SOUNDINGS YIELDS HIGHS IN THE LOW/MID 50S OVER THE WRN INTERIOR. SRLY FLOW WILL KEEP TEMPS MUCH COOLER OVER THE ERN FCST AREA NEAR AND DOWNWIND OF LAKE MICHIGAN. LOCAL COOLING SHOULD ALSO OCCUR NEAR LAKE SUPERIOR OVER THE W AND NCNTRL AREAS MID/LATE AFTN WHERE BOUNDARY LAYER WINDS WILL BE LIGHTER. FROM MUNISING EWD...SRLY FLOW MAY STRONG ENOUGH 10-15 KT TO SUPRESS LAKE BREEZE DEVELOPMENT. NEXT SHORTWAVE FROM ALBERTA IS DUE TO MOVE INTO THE UPR GREAT LAKES LATE FRI NIGHT AND SAT. UPR DIV IN RRQ OF 100 KT 3H JET SHOULD PRODUCE SOME MID CLOUDS PER MODEL SNDGS BUT OTHERWISE MODEL SNDGS LOOK PRETTY DRY AT LOW LEVELS. WEAK PRES GRADIENTS WITH SFC HIGH OVERHEAD WILL ALLOW FOR LAKE BREEZES TO DEVELOP SAT OFF BOTH LAKES SUPERIOR AND MICHIGAN...KEEPING TEMPS COOLER (40S) ALONG LAKESHORE AREAS. MIXING TO AROUND 850 MB OVER THE WESTERN INTERIOR WILL ALLOW MAX TEMPS TO REACH NEAR TO MID 50S. SAT NIGHT...INFLUENCE OF SFC HIGH JUST TO THE NE OF LAKE SUPERIOR WILL ALLOW FOR LIGHT WIND AND GENERALLY CLEAR TO PARTLY CLOUDY SKIES. EXPECT LOWS TO REACH INTO THE 20S OVER THE INTERIOR...CLOSER TO COOLER GFS MOS GUIDANCE. MODELS STILL IN GOOD AGREEMENT SHOWING UPR LOW EJECTING OUT OF THE PLAINS AND INTO THE UPR GREAT LAKES SUN NIGHT INTO MON. AN INCREASING RIBBON OF MOISTURE/ISENTROPIC ASCENT ON THE 300K SFC... A 40KT H85 JET...AND PWATS AROUND AN INCH ARE MAIN TRIGGERS FOR SHOWERS LATE SUN INTO SUN NIGHT. NEG 850-500 MB THETA-E LAPSE RATES COULD ALSO RESULT IN THUNDER. BUMPED UP POPS TO LIKELY SUN NIGHT WITH ARRIVAL OF SFC WARM FRONT AND UPR TROUGH. DEPARTURE OF SHORTWAVE AND ASSOC SFC TROF/WARM FRONT SHOULD TAPER OFF RAIN CHCS BY MON AFTERNOON. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VOSS mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 425 PM EDT THU MAR 22 2007 .SHORT TERM (TONIGHT AND FRIDAY)... MAIN FCST ISSUE IN THE SHORT TERM IS POSSIBILITY OF SOME -SN TONIGHT. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW ZONAL FLOW ACROSS THE NRN CONUS/SRN CANADA. SHORTWAVE THAT PASSED ACROSS THE UPPER LAKES EARLIER TODAY IS NOW OVER THE ONTARIO/QUEBEC BORDER. NEXT SHORTWAVE IN THE FAST FLOW IS OVER NW ND. MID CLOUDS ASSOCIATED WITH SHORTWAVE WERE SPREADING ACROSS NRN MN...AND HIGH CLOUDS HAVE ALREADY SPREAD ACROSS ALL OF UPPER MI THIS AFTN. RADARS SHOW A DECENT AREA OF RETURNS ACROSS FAR NE ND/NW MN AND SRN MANITOBA. SFC OBS THAT REPORT VSBY ARE SPARSE IN THAT AREA...SO DIFFICULT TO KNOW HOW MUCH PCPN IS REACHING THE GROUND. HOWEVER...IN THE LAST FEW HRS...A COUPLE OF OBS IN SRN MANITOBA HAVE REPORTED 1-4SM IN -SN. WELL TO THE W...SHORTWAVE THAT DROPPED OUT OF THE WESTERLIES A DAY OR TWO AGO OVER THE W COAST HAS CLOSED OFF INTO A MIDLEVEL LOW CENTERED JUST S OF CA. THIS SYSTEM WILL BE OF INTEREST TO FCST HERE LATE IN THE UPCOMING WEEKEND AS IT GETS KICKED NE BY NEXT TROF APPROACHING THE W COAST. UPSTREAM SHORTWAVE WILL RACE E...CROSSING UPPER MI/LAKE SUPERIOR BTWN 03Z-09Z. BASED ON THE DARKENING SEEN ON WATER VAPOR IMAGERY... THE GFS HAS A BETTER HANDLE ON SHORTWAVE THAN THE WEAKER NAM. LATEST RUC AND 12Z REGIONAL CANADIAN ALSO SUPPORT THE GFS. OVERLAP OF MODEST DEEP LAYER QVECTOR CONVERGENCE AND MOIST ISENTROPIC ASCENT (CONDENSATION PRES DEFICITS UNDER 20MB) ON THE 290K SFC (AROUND 700MB) LINES UP WELL WITH WHERE RADAR RETURNS ARE PRESENT IN NE ND/NW MN AND SRN MANITOBA. STRONGER ISENTROPIC ASCENT IS INDICATED FARTHER S...BUT AIRMASS IS DRIER THERE. LATEST RUC IS VERY SIMILAR TO THE GFS WITH REGARD TO PROGRESSION OF QVECTOR CONVERGENCE/ISENTROPIC ASCENT THRU 06Z. FORCING/ISENTROPIC ASCENT IS TO SHIFT THRU NE MN BEFORE WEAKENING AS IT CROSSES UPPER MI/LAKE SUPERIOR TONIGHT. WITH ANTECEDENT DRY AIR TO OVERCOME...THE WEAKENING FORCING SUGGESTS PCPN THAT IS OCCURRING UPSTREAM WILL TEND TO DISSIPATE AS IT NEARS AND THEN MOVES ACROSS THE FCST AREA. ON THE OTHER HAND...GIVEN THE APPEARANCE ON WATER VAPOR IMAGERY...SHORTWAVE MAY NOT WEAKEN AS FAST AS MODELS INDICATE. SO...SITUATION IS CERTAINLY STILL WORTHY OF SLIGHT CHC/LOW CHC POPS OVER NW LAKE SUPERIOR AND ACROSS THE KEWEENAW. FCST WETBULB ZERO PROFILES INDICATE ANY PCPN THAT OCCURS WILL BE SNOW. FOLLOWING SHORTWAVE...CANADIAN/GFS SHOW MOISTURE LINGERING AROUND 850MB ON FRI...ESPECIALLY OVER THE CNTRL/ERN FCST AREA. SO THERE SHOULD BE A FAIR AMOUNT OF STRATOCU DEVELOPING DURING THE DAY. MIXING TO 850-800MB ON FCST SOUNDINGS YIELDS HIGHS IN THE LOW/MID 50S. HOWEVER...SRLY FLOW WILL KEEP TEMPS MUCH COOLER NEAR AND DOWNWIND OF LAKE MICHIGAN. LOCAL COOLING SHOULD ALSO OCCUR NEAR LAKE SUPERIOR OVER THE W AND OVER THE NCNTRL MID/LATE AFTN AS BOUNDARY LAYER WINDS SLACKEN. FROM MUNISING EWD...SRLY FLOW MAY BE SUFFICIENT THRU THE DAY TO PREVENT LAKE BREEZE DEVELOPMENT. .LONG TERM (FRIDAY NIGHT THROUGH NEXT THURSDAY)... CONTINUITY IN MODEL SOLUTIONS IS POOR CURRENTLY MAINLY DUE TO ZONAL WEST TO EAST UPPER FLOW ALONG CANADA/UNITED STATES BORDER. IN RECENT MODEL RUNS...IT APPEARED SHORTWAVE CURRENTLY OFF SHORE OF BRITISH COLUMBIA WAS TO MOVE EAST AND ARRIVE OVR ONTARIO AND UPR LAKES FRI NIGHT INTO EARLY SAT. ALSO...THE WAVE WAS PROGGED TO SHEAR OUT AS IT CAME EAST. NOW...A TREND IS EMERGING THAT RESULTS IN STRONGER WAVE NOT COMING THROUGH UNTIL SAT. NAM MOST EMPHATIC WITH THIS IDEA WHILE UKMET/GFS AND LATEST ECMWF ARE WEAKER. SHORTWAVE ALONG WITH DIVERGENCE FM RRQ OF H3 OVR ONTARIO SHOULD PRODUCE CONSIDERABLE MID CLOUDS. HOWEVER...SOUNDINGS FM GFS AND EVEN NAM ARE VERY DRY BLO H85 SO HAVE KEPT A DRY FCST. MIXING HEIGHTS MAY BE LIMITED DUE TO CLOUDS AND LIGHT WINDS SO LOWERED TEMPS SLIGHTLY. AT THE SFC...RIDGE DRIFTING OVER UPR LAKES WILL MOVE TO THE LOWER GREAT LAKES SAT NIGHT INTO SUN. RETURN FLOW AS HIGH DEPARTS WILL ONLY STRENGTHEN THROUGH MOST OF THE UPCOMING WEEK. IT IS FEASIBLE THAT SAT NIGHT WILL BE THE LAST ONE FOR A WHILE WITH A GOOD PORTION OF CWA EXPERIENCING MIN TEMPS BLO FREEZING. UPR LOW OVR SOUTHWEST EJECTS INTO PLAINS SUN AND LIFTS TOWARD UPR GREAT LAKES SUN NIGHT INTO MON. UKMET/GFS/ECMWF IN GOOD AGREEMENT HERE. NAM IS MUCH SLOWER WITH TROUGH EJECTION AND WAS NOT PREFERRED DUE TO EVEN STRONGER KICKER SHORTWAVE TROUGH BARRELLING INTO WEST COAST AS EARLY AS SUN. LARGE AREA OF H85-H7 WARM AIR ADVECTION... 40KT H85 JET...AND PWATS ECLIPSING AN INCH (250-300 PCT OF NORMAL) ARE MAIN TRIGGERS FOR PCPN SUN INTO SUN NIGHT. WARMING H85 TEMPS COMBINED WITH COOL H5 TEMPS AROUND -15C RESULT IN STEEPENING MID LEVEL LAPSE RATES AND POSSIBILITY OF THUNDER. MAIN SFC WARM FRONT AND UPR TROUGH DO NOT ARRIVE UNTIL LATE SUN NIGHT INTO MON WHICH IS WHEN BEST COVERAGE TO SHOWERS/THUNDERSTORMS IS EXPECTED. 00Z GFS EVEN INDICATED SOME SFC BASED INSTABILITY AHEAD OF PRIMARY COLD FRONT MOVING THROUGH MON EVENING. ECMWF MUCH QUICKER WITH FROPA. ALTHOUGH MOST PCPN WILL BE DONE BY MON NIGHT...KEPT A SMALL CHANCE IN GRIDS FOR TUE AS SECONDARY SFC TROUGH MOVES THROUGH PER HPC AND H5 COLD POOL (-20C AT H5) ALSO ROTATES THROUGH. BRIEF RIDGING BOTH ALOFT AND AT SFC FOR WED...THEN DEEP TROUGH CONTINUES TO DEVELOP OVR MUCH OF WESTERN CONUS. SW FLOW DEVELOPING ALOFT...AND EVENTUALLY AT SFC...LEADS TO AN INCREASE IN RAIN CHANCES LATE NEXT WEEK. TEMPS WILL REMAIN ABOVE NORMAL. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...ROLFSON LONG TERM...JLA mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1037 AM EDT THU MAR 22 2007 .UPDATE... WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A POTENT SHORTWAVE RACING E ACROSS ERN LAKE SUPERIOR AND ONTARIO. SHARP DRYING/SUBSIDENCE IN THE WAKE OF SHORTWAVE IS LEADING TO A DECREASE IN CLOUD COVER ACROSS THE FCST AREA THIS MORNING. 00Z/12Z KINL SOUNDINGS SHOWED THE INCOMING DRY AIR NICELY AS PRECIPITABLE WATER DROPPED FROM 0.68 TO 0.15 INCHES...AND 12Z SOUNDING INDICATED DWPT DEPRESSIONS OF 15-25C FROM 840MB TO 550MB. A PERIOD OF GUSTY WINDS IS ALSO FOLLOWING THE STRONG SHORTWAVE. WINDS WERE BEING AIDED BY 4-5MB/3HR PRES RISE MAX THAT WAS QUICKLY MOVING E ACROSS THE UPPER LAKES. CORE OF PRES RISES IS NOW OVER CNTRL LAKE SUPERIOR/CNTRL UPPER MI...SO STRONGEST WINDS HAVE JUST ABOUT PASSED THE AREA. NEXT SHORTWAVE IS HEADING ESE THRU SRN SASKATCHEWAN. MID/HIGH CLOUDS ASSOCIATED WITH SHORTWAVE ARE ALREADY STREAMING E THRU ND INTO NRN MN. INHERITED FCST IS IN GOOD SHAPE FOR THE AFTN AND ONLY REQUIRES MINOR ADJUSTMENTS BASED ON MORNING TRENDS. SOME STRATOCU WILL BE AROUND FOR A FEW MORE HRS...MAINLY ACROSS THE N...ASSOCIATED WITH 850MB THERMAL TROF AND LINGERING LOW-LEVEL MOISTURE. STRATOCU SHOULD BE GONE BY MID/LATE AFTN...BUT ALREADY MID/HIGH CLOUDS ASSOCIATED WITH NEXT SHORTWAVE WILL BE SLIPPING INTO THE FCST AREA FROM THE W. AS FOR TEMPS...MIXING TO 800-850MB ON 12Z KINL SOUNDING SUGGESTS HIGH TEMPS IN THE UPPER 30S/LWR 40S ARE ON TRACK OVER THE W AND N. WNW DOWNSLOPING WIND WILL RESULT IN MAX TEMPS SEVERAL DEGREES HIGHER OVER PORTIONS OF THE CNTRL FCST AREA...ESPECIALLY SCNTRL. AS FOR WINDS...WILL MAINTAIN GALE WARNING OVER ERN LAKE SUPERIOR FOR A FEW MORE HRS WITH EXPECTATION OF GALE FORCE GUSTS. OTHERWISE...WINDS WILL CONTINUE TO DIMINISH OVER THE ENTIRE FCST AREA THRU THE DAY AS PRES RISE SHIFTS E OF THE AREA AND SFC HIGH PRES RIDGE OVER MN DRIFTS E. && .PREV DISCUSSION (ISSUED AT 400 AM EDT)... 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW STRG SHRTWV NEAR LK WINNIPEG EMBEDDED IN ZONAL FLOW ALF ALG THE CNDN BORDER...WITH ANOTHER SHRTWV PRESENT OVER ND. THREE DISTINCT AREAS OF PCPN NOTED AT THE START OF SHIFT. THE FIRST WAS A BAND OF SHRA MOVING INTO WRN LK SUP JUST AHEAD OF COLD FNT IN DPVA/DEEP LYR H85-3 QVECTOR CNVGC ASSOCIATED WITH ND SHRTWV. LLVL MSTR LINGERS BEHIND THIS FNT WITH SC CIGS OBSVD BACK TO THE RED RIVER VALLEY...WHERE DRIER AIR NOTED ON THE BIS SDNG IS WORKING EWD. STRONGER COLD FNT ASSOCIATED WITH SHRTWV OVER LK WINNIPEG MOVING TOWARD THE MN AT 03Z...BUT LTL PCPN OBSVD ALG THIS BNDRY DESPITE SHARPER THERMAL CONTRAST. SECOND CLUSTER OF SHRA WITH EMBEDDED TSRA EXTENDS FM NW WI INTO IA WHERE DPVA/DEEP LYR H85-3 QVECTOR CNVGC/SFC COLD FNT INTERSECTING HIER H85 DWPTS AOA 8C SURGING NEWD IN ADVANCE OF FNT...MSTR NOT AVBL TO BAND FARTHER N IN WRN LK SUP. RAOBS/PROFILERS SHOW H85 SW WINDS AOA 50 KTS AHEAD OF THIS CLUSTER. LARGEST AREA OF SHRA PRESENT OVER ERN WI/LK MI/NW LWR MI AT NOSE OF STRONGEST H85-7 WINDS JUST AHEAD OF WEAK SHRTWV NOTED ON RUC ANALYSIS. SCT SHRA/TSRA ON NRN FRINGE OF THIS AREA ARE IMPACTING THE ERN CWA...BUT FOR THE MOST PART THESE SHRA/TSRA ON TRACK TO MISS THE FA. OTRW...LTL PCPN NOTED OVER THE FA RIGHT NOW...BUT RETURN OF HIER LLVL MSTR OVER MELTING SN HAS CAUSED QUITE A BIT OF ST/FOG...WITH VSBYS AOB 1/4SM AT PLACES ACRS MAINLY THE SCNTRL AND E. UPSTREAM...ANOTHER SHRTWV MOVING THRU BRITISH COLUMBIA. MAIN FCST CONCERNS IN THE SHORT TERM REVOLVE ARND EVOLUTION OF PCPN AREAS AS LATEST RUC/LARGER SCALE MODELS SHOW SHRTWVS OVER ND AND LK WINNIPEG PHASING OVERNGT. FOCUS AFTER COLD FROPA EARLY THIS MRNG SHIFTS TO WINDS/TEMPS. AS SHRTWVS BEGIN TO MERGE TO A 40-UNIT VORT MAX OVER FAR NRN LK SUP BY 12Z THU...EXPECT SHRA AREAS OVER WRN LK SUP/WI TO MERGE OVER THE SCNTRL/ERN CWA WITH SOME LOCALLY HEAVY RA THERE WHERE MSTR CNVGC PHASES BETTER WITH DPVA/FALLING HGTS/DEEP QVECTOR CVNGC BEFORE ACCELERATING INCRSGLY KATAFNT TYPE COLD FNT DRIVES E UNDER JET SURGE REGION OF DEEPENING SHRTWV. WITH RAPID INFLUX OF DRY AIR EXPECTED AS H85 W WINDS INCRS UP TO 50KT...LOOK FOR PCPN/DENSE FOG TO END SOON AFTR COLD FROPA WITH INTENSE DRY ADVCTN/SUBSIDENCE. 00Z RUC/NAM INDICATE DRYING WL REACH ERY ARND 12Z...SO MOST IF NOT ALL PCPN WL BE OVER BY EARLY TDAY. WL CARRY LINGERING SHRA OVER THE ERN COUNTIES EARLY...OTRW HAVE REMOVED POPS ALTOGETHER AS NAM/RUC FCST SDNGS FOLLOWING THE FROPA ARE QUITE DRY. WL EVALUATE NEED TO KEEP GOING DENSE FOG ADVY GOING CLOSE TO FCST ISSUANCE...BUT ANTICIPATE DROPPING ADVY FOR MOST OF THE FA BY FCST ISSUANCE. GFS FCST SDNGS SHOW MORE LLVL MSTR...BUT PREFER THE DRIER LOOK TO THE RUC/NAM FCSTS GIVEN MORE DRYING OBSVD UPSTREAM OVER NW MN/ANTICIPATED DRY SURGE BEHIND DEEPENING SHRTWV. OTRW...LOOK FOR GUSTY WINDS THIS MRNG BEHIND THE BNDRY WITH 35KT WINDS WITHIN THE MIXED LYR TO DIMINISH A BIT THIS AFTN WITH ARRIVAL OF HI PRES RDG. ALTHOUGH PRES GRADIENT SEEMS TO DIMINISH WITH APRCH OF RDG...MIXING/DEEPENING PBL WITH PLENTY OF SUNSHINE IN LLVL CAD SHOULD TAP STRONGER WINDS ALF TO MAINTAIN GUSTINESS THRU THE DAY. MIXING TO H85 ON NAM FCST SDNGS SUGS HI TEMPS WL REACH ARND 45 OVER THE SE COUNTIES...WHERE NW FLOW WL BE DOWNSLOPING. LOOK FOR AN INCRS IN HI CLD LATE TDAY IN ADVANCE OF NEXT SHRTWV NOW MOVING INTO BRITISH COLUMBIA FCST TO MOVE TOWARD NW MN LATE TDAY. FOR TNGT...SHRTWV OVER THE NRN PLAINS PROGGED TO DRIFT ACRS THE UPR GRT LKS...AND GFS/NAM/UKMET SHOW INCRSG MID LVL MSTR. ALTHOUGH LLVLS APPEAR WL BE TOO DRY FOR ANY PCPN...GFS AND ESPECIALLY THE NAM GENERATE SOME GENERALLY LGT QPF OVER THE NW AND LK SUP. NAM ACTUALLY SHOWS SOME SHARP H85-7 FGEN WITH SOME MODEST ISENTROPIC LIFT IN ADVANCE OF THE SHRTWV. SINCE GFS/UKMET ARE MUCH WEAKER WITH FCST DYNAMICS BUT WV IMAGERY INDICATES A WELL DEFINED SHRTWV IN BRITISH COLUMBIA...WL CARRY SLGT CHC -SHSN (FCST WBZ PROFILES SUG ANY PCPN WOULD BE SN) ACRS THE NW CWA ON CYC SIDE OF NAM FCST H3 JET MAX/BEST H85-7 FGEN. EXPECT THE LOWEST MIN TEMPS OVER THE SCNTRL WHERE THE CLDS WL BE THINNEST. FOLLOWING DEPARTURE OF SHRTWV EARLY FRI...SFC-H85 RDG AXIS/MID LVL DRYING FCST TO DOMINATE. GFS/NAM BOTH SHOW SOME HIER DWPTS AT H85 LINGERING HOWEVER...SO EXPECT BKN DIURNAL SC TO DVLP DURING DAY. MIXING TO H85 ON GFS/NAM FCST SDNGS YIELDS HI TEMPS NEAR 55. WITH LGT SW FLOW...EXPECT LK BREEZES/AFTN COOLING TO DVLP MAINLY NEAR LK MI. SOME CONSIDERABLE MODEL DISAGREEMENTS BEGIN TO SHOW IN THE FRI NGT/SAT PDS...NOT SURPRISING CONSIDERING FAST ZONAL FLOW FCST TO PREVAIL. GFS SHOWS A MUCH DEEPER SHRTWV ARRIVING LATE FRI NGT AND GENERATING SGNFT PCPN ON SAT. WL SIDE WITH THE MAJORITY UKMET/ ECWMF/CNDN/NAM THAT SHOW A MUCH WEAKER SHRTWV SHEARING BY ON FRI NGT FOLLOWED BY RDGING ON SAT. OPTED TO REMOVE POPS FRI NGT AND KEEP SAT DRY. WITH H85 TEMPS APRCHG 6C ON SAT...EXPECT TEMPS OVER THE INLAND TO RISE WELL INTO THE 50S TO NEAR 60 PER MIXING TO H8 ON NAM FCST SDNGS. WITH SFC HI CENTER TO THE SE AND CWA IN SYNOPTIC SW FLOW... EXPECT THE MOST SGNFT LK MODERATION OFF LK MI. BUT RELATIVELY WEAK FLOW AND SFC HTG INLAND SHOULD ALLOW LK BREEZES OFF SUPERIOR AS WELL. COORDINATED WITH GRB/DLH. && .MQT WATCHES/WARNINGS/ADVISORIES... GALE WARNING E HALF OF LAKE SUPERIOR. && $$ ROLFSON (UPDATE) KC (PREV DISCUSSION) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 400 AM EDT THU MAR 22 2007 .DISCUSSION... 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW STRG SHRTWV NEAR LK WINNIPEG EMBEDDED IN ZONAL FLOW ALF ALG THE CNDN BORDER...WITH ANOTHER SHRTWV PRESENT OVER ND. THREE DISTINCT AREAS OF PCPN NOTED AT THE START OF SHIFT. THE FIRST WAS A BAND OF SHRA MOVING INTO WRN LK SUP JUST AHEAD OF COLD FNT IN DPVA/DEEP LYR H85-3 QVECTOR CNVGC ASSOCIATED WITH ND SHRTWV. LLVL MSTR LINGERS BEHIND THIS FNT WITH SC CIGS OBSVD BACK TO THE RED RIVER VALLEY...WHERE DRIER AIR NOTED ON THE BIS SDNG IS WORKING EWD. STRONGER COLD FNT ASSOCIATED WITH SHRTWV OVER LK WINNIPEG MOVING TOWARD THE MN AT 03Z...BUT LTL PCPN OBSVD ALG THIS BNDRY DESPITE SHARPER THERMAL CONTRAST. SECOND CLUSTER OF SHRA WITH EMBEDDED TSRA EXTENDS FM NW WI INTO IA WHERE DPVA/DEEP LYR H85-3 QVECTOR CNVGC/SFC COLD FNT INTERSECTING HIER H85 DWPTS AOA 8C SURGING NEWD IN ADVANCE OF FNT...MSTR NOT AVBL TO BAND FARTHER N IN WRN LK SUP. RAOBS/PROFILERS SHOW H85 SW WINDS AOA 50 KTS AHEAD OF THIS CLUSTER. LARGEST AREA OF SHRA PRESENT OVER ERN WI/LK MI/NW LWR MI AT NOSE OF STRONGEST H85-7 WINDS JUST AHEAD OF WEAK SHRTWV NOTED ON RUC ANALYSIS. SCT SHRA/TSRA ON NRN FRINGE OF THIS AREA ARE IMPACTING THE ERN CWA...BUT FOR THE MOST PART THESE SHRA/TSRA ON TRACK TO MISS THE FA. OTRW...LTL PCPN NOTED OVER THE FA RIGHT NOW...BUT RETURN OF HIER LLVL MSTR OVER MELTING SN HAS CAUSED QUITE A BIT OF ST/FOG...WITH VSBYS AOB 1/4SM AT PLACES ACRS MAINLY THE SCNTRL AND E. UPSTREAM...ANOTHER SHRTWV MOVING THRU BRITISH COLUMBIA. MAIN FCST CONCERNS IN THE SHORT TERM REVOLVE ARND EVOLUTION OF PCPN AREAS AS LATEST RUC/LARGER SCALE MODELS SHOW SHRTWVS OVER ND AND LK WINNIPEG PHASING OVERNGT. FOCUS AFTER COLD FROPA EARLY THIS MRNG SHIFTS TO WINDS/TEMPS. AS SHRTWVS BEGIN TO MERGE TO A 40-UNIT VORT MAX OVER FAR NRN LK SUP BY 12Z THU...EXPECT SHRA AREAS OVER WRN LK SUP/WI TO MERGE OVER THE SCNTRL/ERN CWA WITH SOME LOCALLY HEAVY RA THERE WHERE MSTR CNVGC PHASES BETTER WITH DPVA/FALLING HGTS/DEEP QVECTOR CVNGC BEFORE ACCELERATING INCRSGLY KATAFNT TYPE COLD FNT DRIVES E UNDER JET SURGE REGION OF DEEPENING SHRTWV. WITH RAPID INFLUX OF DRY AIR EXPECTED AS H85 W WINDS INCRS UP TO 50KT...LOOK FOR PCPN/DENSE FOG TO END SOON AFTR COLD FROPA WITH INTENSE DRY ADVCTN/SUBSIDENCE. 00Z RUC/NAM INDICATE DRYING WL REACH ERY ARND 12Z...SO MOST IF NOT ALL PCPN WL BE OVER BY EARLY TDAY. WL CARRY LINGERING SHRA OVER THE ERN COUNTIES EARLY...OTRW HAVE REMOVED POPS ALTOGETHER AS NAM/RUC FCST SDNGS FOLLOWING THE FROPA ARE QUITE DRY. WL EVALUATE NEED TO KEEP GOING DENSE FOG ADVY GOING CLOSE TO FCST ISSUANCE...BUT ANTICIPATE DROPPING ADVY FOR MOST OF THE FA BY FCST ISSUANCE. GFS FCST SDNGS SHOW MORE LLVL MSTR...BUT PREFER THE DRIER LOOK TO THE RUC/NAM FCSTS GIVEN MORE DRYING OBSVD UPSTREAM OVER NW MN/ANTICIPATED DRY SURGE BEHIND DEEPENING SHRTWV. OTRW...LOOK FOR GUSTY WINDS THIS MRNG BEHIND THE BNDRY WITH 35KT WINDS WITHIN THE MIXED LYR TO DIMINISH A BIT THIS AFTN WITH ARRIVAL OF HI PRES RDG. ALTHOUGH PRES GRADIENT SEEMS TO DIMINISH WITH APRCH OF RDG...MIXING/DEEPENING PBL WITH PLENTY OF SUNSHINE IN LLVL CAD SHOULD TAP STRONGER WINDS ALF TO MAINTAIN GUSTINESS THRU THE DAY. MIXING TO H85 ON NAM FCST SDNGS SUGS HI TEMPS WL REACH ARND 45 OVER THE SE COUNTIES...WHERE NW FLOW WL BE DOWNSLOPING. LOOK FOR AN INCRS IN HI CLD LATE TDAY IN ADVANCE OF NEXT SHRTWV NOW MOVING INTO BRITISH COLUMBIA FCST TO MOVE TOWARD NW MN LATE TDAY. FOR TNGT...SHRTWV OVER THE NRN PLAINS PROGGED TO DRIFT ACRS THE UPR GRT LKS...AND GFS/NAM/UKMET SHOW INCRSG MID LVL MSTR. ALTHOUGH LLVLS APPEAR WL BE TOO DRY FOR ANY PCPN...GFS AND ESPECIALLY THE NAM GENERATE SOME GENERALLY LGT QPF OVER THE NW AND LK SUP. NAM ACTUALLY SHOWS SOME SHARP H85-7 FGEN WITH SOME MODEST ISENTROPIC LIFT IN ADVANCE OF THE SHRTWV. SINCE GFS/UKMET ARE MUCH WEAKER WITH FCST DYNAMICS BUT WV IMAGERY INDICATES A WELL DEFINED SHRTWV IN BRITISH COLUMBIA...WL CARRY SLGT CHC -SHSN (FCST WBZ PROFILES SUG ANY PCPN WOULD BE SN) ACRS THE NW CWA ON CYC SIDE OF NAM FCST H3 JET MAX/BEST H85-7 FGEN. EXPECT THE LOWEST MIN TEMPS OVER THE SCNTRL WHERE THE CLDS WL BE THINNEST. FOLLOWING DEPARTURE OF SHRTWV EARLY FRI...SFC-H85 RDG AXIS/MID LVL DRYING FCST TO DOMINATE. GFS/NAM BOTH SHOW SOME HIER DWPTS AT H85 LINGERING HOWEVER...SO EXPECT BKN DIURNAL SC TO DVLP DURING DAY. MIXING TO H85 ON GFS/NAM FCST SDNGS YIELDS HI TEMPS NEAR 55. WITH LGT SW FLOW...EXPECT LK BREEZES/AFTN COOLING TO DVLP MAINLY NEAR LK MI. SOME CONSIDERABLE MODEL DISAGREEMENTS BEGIN TO SHOW IN THE FRI NGT/SAT PDS...NOT SURPRISING CONSIDERING FAST ZONAL FLOW FCST TO PREVAIL. GFS SHOWS A MUCH DEEPER SHRTWV ARRIVING LATE FRI NGT AND GENERATING SGNFT PCPN ON SAT. WL SIDE WITH THE MAJORITY UKMET/ ECWMF/CNDN/NAM THAT SHOW A MUCH WEAKER SHRTWV SHEARING BY ON FRI NGT FOLLOWED BY RDGING ON SAT. OPTED TO REMOVE POPS FRI NGT AND KEEP SAT DRY. WITH H85 TEMPS APRCHG 6C ON SAT...EXPECT TEMPS OVER THE INLAND TO RISE WELL INTO THE 50S TO NEAR 60 PER MIXING TO H8 ON NAM FCST SDNGS. WITH SFC HI CENTER TO THE SE AND CWA IN SYNOPTIC SW FLOW... EXPECT THE MOST SGNFT LK MODERATION OFF LK MI. BUT RELATIVELY WEAK FLOW AND SFC HTG INLAND SHOULD ALLOW LK BREEZES OFF SUPERIOR AS WELL. COORDINATED WITH GRB/DLH. && .MQT WATCHES/WARNINGS/ADVISORIES... GALE WARNING LAKE SUPERIOR. && $$ KC mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 1217 PM CDT FRI MAR 23 2007 .UPDATE... UPDATED FOR 18Z AVIATION DISCUSSION. && .AVIATION... MAIN CONCERNS FOR 18Z TAFS INVOLVE AREA OF STRATUS MIGRATING NORTHWARD THIS AFTN AND FOG POTENTIAL IN THE WEST TOWARD MORNING. NAM AND RUC BOTH POINT TOWARD MSP/RNH/EAU BEING MOST AFFECTED...WITH MSP SEEING THE EARLIEST ARRIVAL. OTHERWISE...IT WILL BE A BATTLE BETWEEN MID LEVEL CLDS AT AXN AND STC AND THE INFUSION OF LOW LEVEL MSTR FOR FOG DEVELOPMENT. HAVE PUT SOME MVFR VSBYS IN AT AXN DURING THE FAVORED TIME NEAR DAWN...BUT WITH MID CLDS HANGING AROUND STC LONGER...KEPT THIS SITE VFR. RWF WILL NOT HAVE THE MID/UPR CLDS TO DEAL WITH SO INCLUDED CONSIDERABLE VSBY RESTRICTIONS OVRNGT AND EARLY MRNG. && .PREV DISCUSSION... /ISSUED 255 AM CDT FRI MAR 23 2007/ DISCUSSION... IN THE NEAR TERM...A SPLIT UPPER AIRFLOW REGIME WILL PERSIST ACROSS THE CONUS THROUGH SATURDAY MORNING. THIS WEATHER PATTERN WILL PROVIDE SOME MILD AND DRY WEATHER ACROSS THE UPPER MIDWEST THROUGH SATURDAY. THE LATEST WATER VAPOR SATELLITE PICTURE...SHOWED A WELL-DEFINED UPPER LOW CENTERED OVER BAJA. MEANWHILE...A STRONG UPPER JET EXTENDS FROM THE WESTERN PACIFIC INTO MEXICO. THIS SYSTEM WILL BEGIN TO LIFT SLOWLY NORTHEAST OVER THE SOUTHERN AND CENTRAL ROCKIES. A NEARLY STATIONARY SURFACE FRONTAL BOUNDARY...OVER SOUTHERN IOWA AND NORTHERN ILLINOIS...WILL ALSO SLOWLY MOVE NORTHWARD AS A WARM FRONT OVER THE WEEKEND. THIS FRONTAL BOUNDARY WILL BE OR HAS BEEN THE MAIN FOCUS FOR TSRA. THE EUROPEAN MODEL HAS BEEN CONSISTENT IN THE OVERALL WEATHER PATTERN...WHILE THE GFS AND NAM MODELS SEEN LITTLE TOO FAST. AIRMASS WILL BECOME QUITE UNSTABLE ON SUNDAY AS THE UPPER LOW LIFTS NORTHWARD OVER THE NORTHERN PLAINS. WARM FRONT IS FORECAST TO ADVANCE NORTH OVER SOUTHERN MINNESOTA. FORECAST PARAMETERS ARE INDICATING AT LEAST SLIGHT RISK OF SEVERE STORMS OVER SOUTHERN MINNESOTA SUNDAY AFTERNOON AND EVENING. WIND FIELDS ARE FORECAST TO BE QUITE STRONG BY MID SUNDAY AFTERNOON ACROSS MUCH OF OUR CWA. THIS SHOULD BE SUFFICIENT TO PROVIDE FAVORABLE SHEAR FOR ORGANIZED STORMS...INCLUDING SUPERCELLS WITH HAIL/WIND DAMAGE AND POSSIBLE TORNADOES. QUESTION...IS WHETHER MUCH OF OUR CONVECTION...WILL STAY ELEVATED OR WILL IT BECOME SURFACE BASE OVER SOUTHERN MINNESOTA LATE AFTERNOON AND EVENING...IF THE SURFACE FRONTAL BOUNDARY LIFTS FURTHER NORTHWARD THAN ANTICIPATED. RIGHT NOW...STORM PREDICTION CENTER HAS THE ENTIRE CWA OUTLOOKED IN A SLIGHT RISK FOR SUNDAY. THE LATEST EXTENDED MODELS CONTINUE TO INDICATE AN UNSETTLED WEATHER PATTERN OVER THE UPPER MIDWEST THROUGH MID WEEK. ANOTHER IN A SERIES OF LONGWAVE TROUGH WILL AGAIN AMPLIFY OVER WESTERN U.S. BEFORE LIFTING NORTH OVER THE UPPER MIDWEST...WITH ANOTHER ROUND OF STRONG TO SEVERE STORMS EXPECTED...ESPECIALLY WEDNESDAY. MADE SOME CHANGES TO PREVIOUS FORECAST...RAISED TEMPS OVER THE NEXT FEW DAYS...BOTH MIN/MAX TEMPS AND INCREASE POPS OVER SOUTHWEST HALF OF CWA LATE SATURDAY NIGHT AND SUNDAY. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ mn AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE JACKSON MS 915 AM CDT FRI MAR 23 2007 .SHORT TERM...(TODAY) LATEST SATELLITE IMAGERY SHOWS LINGERING UPPER RIDGE OVER THE REGION...WHICH IS CONTINUING TO CUT OFF LOW LEVEL GULF MOISTURE ACROSS THE REGION. REMOVED PATCHY MORNING FOG IN THE SOUTH AND PUT IN A LITTLE MORE CLOUD COVER FOR PARTLY TO MOSTLY SUNNY SKIES FROM THE HIGH CLOUDS SPILLING IN FROM THE WEST. THE REST OF FORECAST APPEARS TO BE ON TRACK WITH TEMPERATURES QUICKLY RISING TO THE 70S BY NOON BEFORE REACHING THE LOWER 80S THIS AFTERNOON./17/ .AVIATION...VFR CONDITIONS SHOULD PREVAIL THROUGH THE PERIOD AT GWO/GTR/GLH. MVFR VISIBILITIES MAY DEVELOP AROUND 11Z AT JAN/MEI/HBG FOR SATURDAY MORNING. AFTER 15Z...VFR CONDITIONS WILL PREVAIL ACROSS THE WHOLE AREA FOR SATURDAY MORNING. THERE MAY BE A SCT-BKN DECK DEVELOP EACH AFTERNOON...BUT CEILINGS WILL REMAIN WELL ABOVE 3KFT./17/ && .PREVIOUS DISCUSSION...252 AM CDT FRI MAR 23 2007 .SHORT TERM...(TODAY THROUGH SATURDAY)...WARM TEMPERATURES AND DRY WEATHER WILL CONTINUE THROUGH SATURDAY. AT THE SURFACE AN EAST-WEST ORIENTED RIDGE OF HIGH PRESSURE FROM THE ATLANTIC WILL BE OVER THE SOUTHEAST STATES MAINTAINING SOUTHEAST TO SOUTH LOW LEVEL FLOW OVER OUR CWA. ALOFT HIGH PRESSURE OVER THE WESTERN GULF WILL NOSE INLAND OVER OUR CWA AS WELL. LATEST SATELLITE IMAGERY/RUC ANALYSIS SHOWS THE CIRCULATION AROUND A CUT OFF LOW OVER BAJA. THIS LOW IS PROGGED TO MOVE TO THE NORTHEAST OVER THE FOUR CORNERS REGION DURING THE NEXT 36HRS AND HELP STRENGTHEN THE RIDGING IN THE WESTERN GULF. THE RIDGING SURFACE AND ALOFT OVER OUR CWA WILL HELP KEEP THE PRECIPITATION OCCURRING OVER THE SOUTHERN PLAINS TO OUR WEST. MID AND HIGH LEVEL CLOUDS WILL CONTINUE TO SPREAD OVERHEAD FROM THE WEST BUT WL BE WELL ABOVE NORMAL EACH DAY...IN THE LOWER 80S THIS AFTERNOON AND SATURDAY AT MOST SITES. OVERNIGHT LOWS WILL BE ABOVE NORMAL AS WELL TONIGHT WITH MOST SITES BOTTOMING OUT IN THE LOW TO MID 50S. /22/ .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)...THE MID LEVEL RIDGE WILL HOLD TOUGH OVER THE FORECAST AREA INTO MONDAY...CONTINUING TO DEFLECT POTENTIAL SHORTWAVE ENERGY. BY LATE MONDAY AND TUESDAY...THE RIDGE IS FORECAST TO BREAK DOWN ENOUGH TO ALLOW DEEPER MOISTURE TO MOVE IN...AND WITH THE APPROACH OF A SRN STREAM PERTURBATION...THE CHANCE POPS INDICATED BY GFS MOS SEEM REASONABLE. WITH PASSAGE OF THE TROUGH THE MID LEVEL RIDGE IS FORECAST TO REBUILD OVER THE AREA FOR THE MID WEEK BRINGING A RETURN TO WARM AND DRY WEATHER. THERE ARE STILL INDICATIONS IN THE MODELS THAT A MORE ACTIVE PATTERN WILL TAKE SHAPE OVER THE LOWER MS VALLEY REGION BY NEXT FRIDAY AS STRONG WESTERLIES CARVE OUT A TROUGH OVER THE WRN/CNTRL CONUS AND FORCE A BREAKDOWN OF THE RIDGE. THE GFS/ ECMWF ARE CONSISTENT IN SHOWING THIS BREAK-DOWN...AND WILL KEEP THE CHANCE POPS OFFERED BY MEX MOS. /EC/ && .AVIATION...VFR CONDITIONS SHOULD PREVAIL THROUGH THE PERIOD AT GWO/GTR/GLH. MVFR VISIBILITIES MAY DEVELOP AROUND 11Z AT JAN/MEI THIS MORNING AND AGAIN SATURDAY MORNING. IFR CONDITIONS ARE EXPECTED TO DEVELOP AROUND 11Z AT HBG AGAIN THIS MORNING AND SATURDAY MORNINGS. AFTER 15Z...VFR CONDITIONS WILL PREVAIL ACROSS THE WHOLE AREA EACH MORNING. THERE MAY BE A SCT-BKN DECK DEVELOP EACH AFTERNOON...BUT CEILINGS WILL REMAIN WELL ABOVE 3KFT. /22/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 82 54 84 55 / 2 2 3 3 MERIDIAN 83 52 85 54 / 2 2 2 2 VICKSBURG 82 56 84 57 / 3 2 3 3 HATTIESBURG 82 54 84 54 / 3 2 2 5 NATCHEZ 81 56 83 58 / 3 2 3 4 GREENVILLE 81 57 83 57 / 7 2 3 3 GREENWOOD 83 56 85 57 / 6 2 3 3 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ SHORT TERM/AVIATION: 22 LONG TERM: EC ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 252 AM CDT FRI MAR 23 2007 .SHORT TERM...(TODAY THROUGH SATURDAY)...WARM TEMPERATURES AND DRY WEATHER WILL CONTINUE THROUGH SATURDAY. AT THE SURFACE AN EAST-WEST ORIENTED RIDGE OF HIGH PRESSURE FROM THE ATLANTIC WILL BE OVER THE SOUTHEAST STATES MAINTAINING SOUTHEAST TO SOUTH LOW LEVEL FLOW OVER OUR CWA. ALOFT HIGH PRESSURE OVER THE WESTERN GULF WILL NOSE INLAND OVER OUR CWA AS WELL. LATEST SATELLITE IMAGERY/RUC ANALYSIS SHOWS THE CIRCULATION AROUND A CUT OFF LOW OVER BAJA. THIS LOW IS PROGGED TO MOVE TO THE NORTHEAST OVER THE FOUR CORNERS REGION DURING THE NEXT 36HRS AND HELP STRENGTHEN THE RIDGING IN THE WESTERN GULF. THE RIDGING SURFACE AND ALOFT OVER OUR CWA WILL HELP KEEP THE PRECIPITATION OCCURRING OVER THE SOUTHERN PLAINS TO OUR WEST. MID AND HIGH LEVEL CLOUDS WILL CONTINUE TO SPREAD OVERHEAD FROM THE WEST BUT WL BE WELL ABOVE NORMAL EACH DAY...IN THE LOWER 80S THIS AFTERNOON AND SATURDAY AT MOST SITES. OVERNIGHT LOWS WILL BE ABOVE NORMAL AS WELL TONIGHT WITH MOST SITES BOTTOMING OUT IN THE LOW TO MID 50S. /22/ .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)...THE MID LEVEL RIDGE WILL HOLD TOUGH OVER THE FORECAST AREA INTO MONDAY...CONTINUING TO DEFLECT POTENTIAL SHORTWAVE ENERGY. BY LATE MONDAY AND TUESDAY...THE RIDGE IS FORECAST TO BREAK DOWN ENOUGH TO ALLOW DEEPER MOISTURE TO MOVE IN...AND WITH THE APPROACH OF A SRN STREAM PERTURBATION...THE CHANCE POPS INDICATED BY GFS MOS SEEM REASONABLE. WITH PASSAGE OF THE TROUGH THE MID LEVEL RIDGE IS FORECAST TO REBUILD OVER THE AREA FOR THE MID WEEK BRINGING A RETURN TO WARM AND DRY WEATHER. THERE ARE STILL INDICATIONS IN THE MODELS THAT A MORE ACTIVE PATTERN WILL TAKE SHAPE OVER THE LOWER MS VALLEY REGION BY NEXT FRIDAY AS STRONG WESTERLIES CARVE OUT A TROUGH OVER THE WRN/CNTRL CONUS AND FORCE A BREAKDOWN OF THE RIDGE. THE GFS/ ECMWF ARE CONSISTENT IN SHOWING THIS BREAK-DOWN...AND WILL KEEP THE CHANCE POPS OFFERED BY MEX MOS. /EC/ && .AVIATION...VFR CONDITIONS SHOULD PREVAIL THROUGH THE PERIOD AT GWO/GTR/GLH. MVFR VISIBILITIES MAY DEVELOP AROUND 11Z AT JAN/MEI THIS MORNING AND AGAIN SATURDAY MORNING. IFR CONDITIONS ARE EXPECTED TO DEVELOP AROUND 11Z AT HBG AGAIN THIS MORNING AND SATURDAY MORNINGS. AFTER 15Z...VFR CONDITIONS WILL PREVAIL ACROSS THE WHOLE AREA EACH MORNING. THERE MAY BE A SCT-BKN DECK DEVELOP EACH AFTERNOON...BUT CEILINGS WILL REMAIN WELL ABOVE 3KFT. /22/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 82 54 84 55 / 2 2 3 3 MERIDIAN 83 52 85 54 / 2 2 2 2 VICKSBURG 82 56 84 57 / 3 2 3 3 HATTIESBURG 82 54 84 54 / 3 2 2 5 NATCHEZ 81 56 83 58 / 3 2 3 4 GREENVILLE 81 57 83 57 / 7 2 3 3 GREENWOOD 83 56 85 57 / 6 2 3 3 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ SHORT TERM/AVIATION: 22 LONG TERM: EC ms AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE JACKSON MS 935 AM CDT THU MAR 22 2007 .SHORT TERM...LATEST SATELLITE IMAGERY SHOWS THE REGION UNDER AN UPPER RIDGE...WHICH IS CONTINUING OUR LONG ROUND OF DRY WEATHER. SHOULD GET SOME SCATTERED CLOUDS MOSTLY IN THE FORM OF HIGH LEVEL CLOUDS FOR THIS AFTERNOON. THE FOG HAS LIFTED OVER OUR THE SOUTHEAST ZONES...SO HAVE ALLOWED THE DENSE FOG ADVISORY TO EXPIRE. CURRENT HIGHS IN THE LOWER 80S SEEMS TO BE ON TRACK. SO WILL MAKE NO OTHER CHANGES TO THE ZONES./17/ .AVIATION...PATCHES OF LIFR CIGS/VSBY WILL BE POSSIBLE IN AREAS ALONG AND S OF HIGHWAY 84 FOR FRIDAY MORNING. VFR CONDITIONS ARE EXPECTED TO RESUME AREAWIDE BY 15Z FRIDAY./17/ .PREVIOUS DISCUSSION... TODAY THROUGH FRIDAY...GRADIENT WINDS HAVE CONTINUED OVER MUCH OF CWA THIS MORNING WITH THE EXCEPTION OF SOUTHEAST MISSISSIPPI LAST HOUR. PINE BELT AIRPORT WAS REPORTING VISIBILITY RESTRICTIONS ALREADY. WL CONTINUE TO MONITOR OUR SOUTHEAST ZONES FOR AN ADVISORY AGAIN THIS MORNING...BUT CURRENTLY EXPECTING ANY DENSE FOG DEVELOPMENT TO REMAIN PATCHY. ELSE...WARM TEMPERATURES AND DRY WEATHER WILL CONTINUE THROUGH FRIDAY. AT THE SURFACE AN EAST-WEST ORIENTED RIDGE OF HIGH PRESSURE FROM THE ATLANTIC WILL BE OVER THE SOUTHEAST STATES MAINTAINING SOUTHEAST TO SOUTH LOW LEVEL FLOW OVER OUR CWA. ALOFT HIGH PRESSURE OVER THE WESTERN GULF WILL BUILD INLAND OVER OUR CWA AS WELL. LATEST SATELLITE IMAGERY/RUC ANALYSIS SHOWS THE CIRCULATION AROUND A CUT OFF LOW DROPPING SOUTH OFF THE SOUTHERN CALIFORNIA COAST. THIS LOW IS PROGGED TO MOVE OVER BAJA DURING THE NEXT 36HRS AND HELP STRENGTHEN THE RIDGING IN THE WESTERN GULF. THE RIDGING SURFACE AND ALOFT OVER OUR CWA WILL HELP KEEP THE PRECIPITATION OCCURRING OVER THE SOUTHERN PLAINS TO OUR WEST. SOME MID AND HIGH LEVEL CLOUDS WILL SPREAD OVERHEAD FROM THE WEST BUT WL STILL REACH WELL ABOVE NORMAL...AROUND 80 DEGREES THIS AFTERNOON AND FRIDAY AT MOST SITES. OVERNIGHT LOWS WILL BE ABOVE NORMAL AS WELL TONIGHT WITH MOST SITES BOTTOMING OUT IN THE LOW TO MID 50S. /22/ FRIDAY NIGHT THROUGH NEXT WEEK... THE MID LEVEL RIDGE WILL HOLD TOUGH OVER THE FORECAST AREA THIS WEEKEND...TENDING TO DEFLECT ANY POTENTIAL SHORTWAVE TROUGHS. WITH THAT IN MIND...THE GFS SEEMS A LITTLE TOO QUICK IN INCREASING RAIN CHANCES SUNDAY AND SUNDAY NIGHT AND WILL KEEP THE FORECAST DRY. BY MONDAY...THE RIDGE IS FORECAST TO BREAK DOWN ENOUGH TO ALLOW DEEPER MOISTURE TO MOVE IN...AND WITH THE APPROACH OF A SRN STREAM PERTURBATION... THE CHANCE POPS INDICATED BY GFS MOS SEEM REASONABLE. THE MID LEVEL RIDGE REBUILDS OVER THE AREA FOR THE MID WEEK BRINGING A RETURN TO WARM AND DRY WEATHER FOR THE FORECAST AREA. THERE ARE INDICATIONS THAT A MORE ACTIVE PATTERN COULD TAKE SHAPE OVER THE LOWER MS VALLEY REGION NEXT WEEKEND AS STRONG WESTERLIES CARVE OUT A TROUGH OVER THE WRN/CNTRL CONUS. THE GFS/UKMET/ECMWF ARE ALL IN AGREEMENT ON THIS SCENARIO...BUT PERSISTENCE CERTAINLY ARGUES AGAINST IT. /EC/ .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 230 AM CDT THU MAR 22 2007 .DISCUSSION... TODAY THROUGH FRIDAY...GRADIENT WINDS HAVE CONTINUED OVER MUCH OF CWA THIS MORNING WITH THE EXCEPTION OF SOUTHEAST MISSISSIPPI LAST HOUR. PINE BELT AIRPORT WAS REPORTING VISIBILITY RESTRICTIONS ALREADY. WL CONTINUE TO MONITOR OUR SOUTHEAST ZONES FOR AN ADVISORY AGAIN THIS MORNING...BUT CURRENTLY EXPECTING ANY DENSE FOG DEVELOPMENT TO REMAIN PATCHY. ELSE...WARM TEMPERATURES AND DRY WEATHER WILL CONTINUE THROUGH FRIDAY. AT THE SURFACE AN EAST-WEST ORIENTED RIDGE OF HIGH PRESSURE FROM THE ATLANTIC WILL BE OVER THE SOUTHEAST STATES MAINTAINING SOUTHEAST TO SOUTH LOW LEVEL FLOW OVER OUR CWA. ALOFT HIGH PRESSURE OVER THE WESTERN GULF WILL BUILD INLAND OVER OUR CWA AS WELL. LATEST SATELLITE IMAGERY/RUC ANALYSIS SHOWS THE CIRCULATION AROUND A CUT OFF LOW DROPPING SOUTH OFF THE SOUTHERN CALIFORNIA COAST. THIS LOW IS PROGGED TO MOVE OVER BAJA DURING THE NEXT 36HRS AND HELP STRENGTHEN THE RIDGING IN THE WESTERN GULF. THE RIDGING SURFACE AND ALOFT OVER OUR CWA WILL HELP KEEP THE PRECIPITATION OCCURRING OVER THE SOUTHERN PLAINS TO OUR WEST. SOME MID AND HIGH LEVEL CLOUDS WILL SPREAD OVERHEAD FROM THE WEST BUT WL STILL REACH WELL ABOVE NORMAL...AROUND 80 DEGREES THIS AFTERNOON AND FRIDAY AT MOST SITES. OVERNIGHT LOWS WILL BE ABOVE NORMAL AS WELL TONIGHT WITH MOST SITES BOTTOMING OUT IN THE LOW TO MID 50S. /22/ FRIDAY NIGHT THROUGH NEXT WEEK... THE MID LEVEL RIDGE WILL HOLD TOUGH OVER THE FORECAST AREA THIS WEEKEND...TENDING TO DEFLECT ANY POTENTIAL SHORTWAVE TROUGHS. WITH THAT IN MIND...THE GFS SEEMS A LITTLE TOO QUICK IN INCREASING RAIN CHANCES SUNDAY AND SUNDAY NIGHT AND WILL KEEP THE FORECAST DRY. BY MONDAY...THE RIDGE IS FORECAST TO BREAK DOWN ENOUGH TO ALLOW DEEPER MOISTURE TO MOVE IN...AND WITH THE APPROACH OF A SRN STREAM PERTURBATION... THE CHANCE POPS INDICATED BY GFS MOS SEEM REASONABLE. THE MID LEVEL RIDGE REBUILDS OVER THE AREA FOR THE MID WEEK BRINGING A RETURN TO WARM AND DRY WEATHER FOR THE FORECAST AREA. THERE ARE INDICATIONS THAT A MORE ACTIVE PATTERN COULD TAKE SHAPE OVER THE LOWER MS VALLEY REGION NEXT WEEKEND AS STRONG WESTERLIES CARVE OUT A TROUGH OVER THE WRN/CNTRL CONUS. THE GFS/UKMET/ECMWF ARE ALL IN AGREEMENT ON THIS SCENARIO...BUT PERSISTENCE CERTAINLY ARGUES AGAINST IT. /EC/ && .AVIATION...PATCHES OF LIFR CIG/VSBY WILL BE POSSIBLE IN AREAS ALONG AND S OF HIGHWAY 84 THIS MORNING AND AGAIN FRIDAY MORNING. VFR CONDITIONS ARE EXPECTED TO RESUME AREAWIDE BY 15Z EACH MORNING. /22/ && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ SHORT TERM: 22 LONG TERM: EC ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 1103 PM CDT FRI MAR 23 2007 .UPDATE... HAVE UPDATED FORECAST TO LESSEN CHANCE OF RAIN OVER MOST OF THE AREA TONIGHT AS LARGE AREA OF SHRA AND EMBEDDED ISOLD TSRA HAS QUICKLY DIMINISHED OVER SRN MO. HAVE ALSO CUT BACK ON THE QPF GRIDS OVER THE SRN COUNTIES BASED ON THIS. THERE WILL CONTINUE TO BE SOME CHC OF TSRA BY 09-12Z AS THE RUC SHOWS A MODEST INCREASE IN INSTABILITY AND LOW LEVEL FORCING ASSOCIATED WITH A BROAD LOW LEVEL JET. BEST CHC FOR SHRA/TSRA TOMORROW WILL BE OVER THE NRN COUNTIES WHICH IS IN CLOSE PROXIMITY TO STATIONARY FRONT. OTHERWISE ONLY MINOR CHANGES TO GOING FORECAST. BRITT && .DISCUSSION... FRONTAL BOUNDARY HAS MOVED NORTHWARD AND EXTENDED ACROSS NORTHERN IL INTO CENTRAL IA. EXPECT THE FRONT TO REMAIN TO OUR NORTH OVER THE WEEKEND. A WARM SOUTHERLY FLOW WILL CONTINUE ACROSS THE REGION THROUGH THE WEEKEND. CONVECTION CONTINUES TO MOVE OUT OF SOUTHEAST KS/SOUTHWEST MO INTO THE EASTERN OZARKS AT THIS TIME. SHOWERS CONTINUED ACROSS MUCH OF SOUTHWEST IL. UPPER LEVEL CLOSED LOW OVER NORTHERN MEXICO WILL OPEN UP AND MOVE NORTHEASTWARD OVER THE WEEKEND. THE SHORT WAVE IS FORECAST TO BE LOCATED OVER THE UPPER MIDWEST BY MONDAY MORNING. THE GFS AND EUROPEAN ARE SIMILAR IN MOVING A DEEP UPPER TROF ACROSS THE WESTERN U.S. EARLY AND THE MIDDLE OF NEXT WEEK. THIS SYSTEM IS FORECAST TO SWING INTO THE NORTHERN PLAINS BY THURSDAY. IN RESPONSE, A DEEP SURFACE LOW WILL DEVELOP OVER THE NORTHERN ROCKIES ON TUESDAY. A WARM MOIST SOUTHERLY FLOW IS EXPECTED TO CONTINUE ACROSS THE AREA UNTIL LATE NEXT WEEK. IF THE MODELS ARE ON TRACK, A COLD FRONT WILL MOVE ACROSS THE REGION ON THURSDAY. && .AVIATION... FOR THE 06Z TAFS...S-SWLY SFC WNDS WL CONT OVR THE CWA AS THE WRMFNT HAS PUSHED N OF THE CWA. THE ERN END OF THIS FRONT MAY ACTUALLY SINK BACK SWD INTO UIN SAT AFTN AS A SFC RDG BLDS SEWD THRU THE GRT LKS REGION INTO THE OH VLY. LOOKING AT MDL QPF IT APRS THAT THE BEST POTENTIAL FOR CONVECTION SHOULD OCCUR AT THE UIN TAF SITE ON SAT AS THIS FRONT BACKDOORS TOWARDS UIN AND A WK SHRTWV TROF MOVES NEWD INTO IA SAT AFTN. MAY BE SCT SHRA OR TSRA FURTHER S WITH AT LEAST WK LOW-MID LVL WAA ACRS AREA BUT WILL LEAVE OUT OF THE TAFS FOR NOW. MDL RH PROGS CONT TO INDICATE PLENTY OF RH BWTN 850 MB AND 700 MB LT TGT INTO SAT. SHOULD CONT TO HAVE STRATUS IN UIN LT TGT WITH LGT FOG DVLPG. FOG HAS RECENTLY DVLPD IN THE STL METRO AREA WITH MID-HI LVL CLOUD CVR THINNING OUT AND PLENTY OF BREAKS IN THE LOW LVL CLOUD CVR. WILL MENTION AT LEAST LGT FOG IN STL AND SUS LT TGT INTO SAT MRNG AND MAY ALSO MENTION LGT FOG DVLPG IN COU AS WELL AS LOW LVL CLOUD DECK OVR COU IS SHOWING SOME CLRG TO THE SOUTH ON THE LATEST SATELLITE LOOP. GKS && .PRELIMINARY POINT TEMPS/POPS... ST LOUIS 59 78 63 79 / 30 40 10 20 QUINCY 57 72 55 77 / 40 70 30 30 COLUMBIA 60 77 59 80 / 30 40 20 30 JEFFERSON CITY 60 77 59 80 / 20 40 20 30 SALEM 57 76 58 78 / 30 40 10 20 FARMINGTON 59 78 58 79 / 20 30 10 20 && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPRINGFIELD MO 905 PM CDT FRI MAR 23 2007 .UPDATE... THE LAST OF THE STORMS THAT DEVELOPED THIS AFTERNOON WILL EXIT OUR SOUTHEAST COUNTIES THROUGH 04Z...SO HAVE ALREADY LOWERED PRECIPITATION CHANCES THROUGH THE EVENING AND OVERNIGHT HOURS. WILL BE WATCHING STORMS OVER CENTRAL/WESTERN KANSAS CLOSELY. GIVEN CURRENT EASTWARD PROGRESSION...THE STORMS WILL REMAIN WEST OF OUR CWA THROUGH TONIGHT. CANNOT RULE OUT STORM DEVELOPMENT AHEAD OF CURRENT STORM AREA WITH RELATIVELY UNCAPPED AND HUMID AIRMASS OVER OUR AREA...BUT PLAN TO KEEP CHANCES ON THE LOW SIDE WITH LACK OF SURFACE FOCUS AND MAIN LOW LEVEL JET REMAINING TO OUR WEST. TEMPERATURE FORECAST FOR TONIGHT LOOKS GOOD WITH LIMITED DIURNAL RANGE AS DEWPOINTS REMAIN IN THE UPPER 50S. TERRY .PREVIOUS DISCUSSION...//215 PM CDT FRI MAR 23 2007// CONVECTION CONTINUES TO EXPAND WITH THE ORIENTATION SHIFTING MORE WEST TO EAST. DECENT LOW LEVEL MOISTURE TRANSPORT CONTINUES TO FEED INTO BROAD DIFFLUENCE ALOFT AHEAD OF A MID LEVEL SHEAR AXIS. ORIGINATION POINT OF CONVECTION IN SE KS/NE OK HAS SHIFTED VERY LITTLE OVER THE PAST SEVERAL HOURS. WHAT WAS ONCE A SW TO NE ORIENTATION HAS SHIFTED A BIT MORE TOWARDS A W-E AXIS...PARTIALLY DUE TO A SLIGHT VEER IN THE 925/850MB WIND DIRECTIONS PER THE LATEST RUC INITIALIZATIONS. PRECIPITATION CHANCES TONIGHT WILL BE TIED MAINLY TO THE EVOLUTION AND MOVEMENT OF THE ONGOING CONVECTION. GIVEN MOIST ENVIRONMENT... GOOD SUPPORT ALOFT GIVEN UPPER DIFFLUENCE AND THE MID LEVEL SHEAR AXIS...HAVE OPTED TO EXPAND CATEGORICAL POPS EASTWARD AND NORTHWARD. GAGAN/FOSTER NOT MUCH CHANGE IN THE OVERALL PATTERN AS WE HEAD INTO THE WEEKEND. OUR REGION WILL REMAIN UNDER THE INFLUENCE OF A DEEP SOUTHWESTERLY FLOW BETWEEN AN UPPER RIDGE ANCHORED OVER THE SOUTHEASTERN U.S. AND CUT OFF LOW OVER THE DESERT SOUTHWEST. THE UPPER LOW IN THE SOUTHWEST U.S. WILL LIFT NORTH NORTHEAST AROUND THE PERIPHERY OF THE RIDGE THIS WEEKEND. THIS WILL INDUCE THE DEVELOPMENT OF A SURFACE LOW ACROSS THE HIGH PLAINS. AS A RESULT A WARM FRONT WILL DEVELOP OR STRENGTHEN WHICH WE MAY BE SEEING THE ORIGINS NOW ACROSS SOUTHERN MISSOURI. MODELS HAVE TRENDED STRONGER WITH UPPER RIDGING INTO THE OZARKS THIS WEEKEND AND THUS KEEP PRECIPITATION CHANCES MAINLY TO THE WEST OF THE AREA. ALL OF THE OZARKS REGION AND OSAGE PLAINS WILL BE ENVELOPED BY THE WARM SECTOR SATURDAY AND SUNDAY. MORE SUNSHINE AND INCREASING SOUTHERLY FLOW SHOULD PUSH TEMPERATURES TO AROUND 80 DEGREES. IF NEAR FULL SUNSHINE DEVELOPS WOULD NOT BE SURPRISED TO SEE LOWER OR EVEN MIDDLE 80S IN A FEW SPOTS. NEXT IN SERIES OF SHORTWAVES WILL LIFT NORTHEAST TOWARD THE AREA EARLY NEXT WEEK PROVIDING A CHANCE OF SCATTERED CONVECTION. BETTER CHANCES OF THUNDERSTORMS WILL ARRIVE LATER WEDNESDAY OR THURSDAY OF NEXT WEEK AS A MORE SIGNIFICANT UPPER TROUGH SWINGS EAST ACROSS THE ROCKIES. FOSTER && .AVIATION... FOR THE 00Z TAF PACKAGE...WILL KEEP VFR CONDITIONS GOING THROUGH THE FORECAST PERIOD. HAD SOME CONCERNS ABOUT FOG TONIGHT WITH RESIDUAL MOISTURE FROM EARLIER STORMS. HOWEVER EXPECT WINDS TO STAY UP AROUND 10 KNOTS THROUGH THE NIGHT WHICH SHOULD KEEP LOWER LEVELS MIXED ENOUGH TO LIMIT FOG POTENTIAL. HAVE CARRIED VICINITY THUNDER AFTER 18Z AS MOIST AIRMASS OVER THE REGION DESTABILIZED WITH AFTERNOON HEATING. FOR NOW THINK MAJORITY OF STORMS OVER WESTERN/CENTRAL KANSAS WILL REMAIN WEST OF THE AIRPORTS THROUGH TONIGHT. TERRY && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. $$ WFO SGF mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 835 CDT FRI MAR 23 2007 ...UPDATED AVIATION DISCUSSION... .DISCUSSION... HAVE LOWERED POPS A LITTLE AS THE LOW LEVEL JET WILL BE FOCUSED MAINLY TO THE WEST OF THE CWA. A WEAK SHORTWAVE EJECTING NORTHEAST FROM THE SOUTH PLAINS...ALONG WITH WEAK ISENTROPIC LIFT...MAY STILL GENERATE SOME WIDELY SCATTERED TO SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY AFTER MIDNIGHT. THE GREATEST THREAT WILL BE ACROSS THE EXTREME NORTHERN PORTION OF THE CWA WHERE ISENTROPIC LIFT ON THE 300K SURFACE IS THE STRONGEST. DB && .PREVIOUS DISCUSSION... 415 PM... MOST OF THE PRECIP HAS NOW EXITED THE CWA THIS AFTERNOON WITH THE COMPLEX OF STORMS ACROSS SOUTHEASTERN KANSAS INTO CENTRAL MISSOURI NOW TRAINING JUST SOUTH OF LINN/BUTLER/BATES COUNTIES. A FEW LIGHT SHOWERS JUST NORTH OF THE KC METRO AREA WITH A FEW ADDITIONAL SHOWERS TRAILING BACK FURTHER WEST TOWARDS TOPEKA. THIS ACTIVITY APPEARS TO BE ASSOCIATED WITH A WEAK DISTURBANCE NEAR H7 AS NOTED VIA RUC MOISTURE PROG. AS THIS SPREADS EASTWARD...MAY SEE A FEW ADDITIONAL SHOWERS DEVELOP ACROSS NE KS AND NW MO THROUGH THE REMAINDER OF THE AFTERNOON. STATIONARY FRONTAL BOUNDARY NOW LOCATED NEAR OR JUST NORTH OF THE MO/IA BORDER THIS AFTERNOON WITH SOME BREAKS IN THE CLOUD DECK NOTED VIA VIS SATELLITE NEAR THE BOUNDARY. MODEL CONSENSUS KEEPS HIGHEST QPF CLOSER TO THE FRONT OVERNIGHT COINCIDENT WITH HIGHER LOW LEVEL MOISTURE CONTENT AND SOMEWHAT STRONGER 295-300K ISENTROPIC ASCENT. HOWEVER...APPEARS CORE OF LLJ WILL REMAIN SOUTH AND WEST OF THE AREA ACROSS THE SOUTHERN PLAINS WITH AFOREMENTIONED BOUNDARY MORE DIFFUSE OVERNIGHT. NONETHELESS...HAVE EDGED POPS UP ACROSS THE AREA WITH HIGHER AMOUNTS ACROSS THE NORTHERN COUNTIES...ALTHOUGH CONFIDENCE IS NOT HIGH WITH REGARDS TO PRECIP PLACEMENT. ATTENTION THEN TURNS TO MAIN UPPER LEVEL LOW AS IT EJECTS ACROSS THE CENTRAL PLAINS THIS WEEKEND. TOUGH TO GAGE PRECIP EPISODES WITH SEVERAL WAVES EMBEDDED WITHIN SOUTHWESTERLY FLOW. 60KT H5 JET PROGGED TO EMERGE ACROSS CENTRAL KS TOMORROW AFTERNOON AND EVENING. BELIEVE STRONGEST CONVECTIVE ACTIVITY WILL REMAIN TO OUR WEST CLOSER TO STRONGER JET DYNAMICS. HOWEVER...DEPENDING ON AMOUNT OF HEATING RECEIVED TOMORROW AFTERNOON...CANNOT RULE OUT THUNDERSTORM ACTIVITY DEVELOPING ALONG AND SOUTH OF OLD BOUNDARY. UPPER LOW TO THEN SWING INTO NORTH CENTRAL NE AND SOUTH CENTRAL SD BY SUNDAY MORNING. MODELS DIFFER A BIT ON PLACEMENT OF JET DURING THE AFTERNOON. HOWEVER...APPEARS JET AXIS WILL ALIGN FROM CENTRAL IA SOUTHWARD INTO NORTHERN MISSOURI. AS THIS OCCURS...DRYLINE WILL PUSH INTO EASTERN KS DURING THE AFTERNOON SUNDAY AND ACT AS THE FOCUS FOR THUNDERSTORM DEVELOPMENT. STILL A BIT FAR OUT...BUT IF DYNAMICS COME TOGETHER AND SUFFICIENT THERMODYNAMICS ARE REALIZED...SOME SEVERE ACTIVITY WILL BE POSSIBLE. OTHERWISE...WILL CONTINUE WITH WARM MOIST PATTERN AS SOUTHERN FLOW CONTINUES WITH THE BOUNDARY REMAINING TO THE NORTH. DEROCHE EXTENDED DISCUSSION (MON THROUGH FRI)... THE UNSETTLED WEATHER PATTERN LOOKS TO PERSIST THROUGH NEXT WEEK. SEGMENTS OF THE MID/UPPER TROUGH WILL CONTINUE TO EJECT NORTHEAST OVER THE EASTERN RIDGE EARLY NEXT WEEK. MEANWHILE THE ASSOCIATED MID/UPPER WEAKNESS WILL TRACK EAST ACROSS THE SOUTHERN/GULF STATES. THE FORECAST AREA WILL BE BETWEEN THESE TWO PORTIONS OF THE UPPER SYSTEM...WITH RELATIVELY WEAK/ELONGATED SHORTWAVE ENERGY ADVANCING ACROSS THE AREA. AS A RESULT...HAVE CONTINUED LOW END SHOWER AND THUNDERSTORM CHANCES ON MONDAY OF NEXT WEEK. UNSEASONABLY WARM TEMPERATURES WILL CONTINUE THROUGH MID WEEK NEXT WEEK...WITH SHORTWAVE RIDGING PROGRESSING ACROSS THE MIDWEST. ANOTHER MID/UPPER TROUGH WILL ENTER THE WESTERN CONUS EARLY NEXT WEEK...AND IS EXPECTED TO EVENTUALLY LIFT NORTHEAST ACROSS THE ROCKIES AND TOWARD THE NORTHERN PLAINS. THE ATTENDANT SURFACE COLD FRONT IS FORECAST TO REACH THIS FORECAST AREA LATE WEDNESDAY INTO THURSDAY...AND BRING AN INCREASED CHANCE FOR MORE SHOWER AND THUNDERSTORM ACTIVITY. STOFLET .AVIATION... AREA OF CEILINGS FROM 1000-1500 FEET FROM MKC TO STJ SLOWLY MIGRATING NORTH. CEILINGS IMPROVING TO THE SOUTH OF THE KANSAS CITY METRO. NOCTURNAL COOLING IN A MOIST AIR MASS IS MAKING CEILING FORECASTING TRICKY. MAY NEED TO RAISE CEILINGS TO VFR AT 04-07Z IF IMPROVING TREND CONTINUES. CANNOT DISCOUNT A PERIOD OF MVFR CEILINGS FROM 10-15Z. DB && .EAX WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. $$ mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 414 PM CDT FRI MAR 23 2007 .DISCUSSION (FRI THROUGH SUN)... MOST OF THE PRECIP HAS NOW EXITED THE CWA THIS AFTERNOON WITH THE COMPLEX OF STORMS ACROSS SOUTHEASTERN KANSAS INTO CENTRAL MISSOURI NOW TRAINING JUST SOUTH OF LINN/BUTLER/BATES COUNTIES. A FEW LIGHT SHOWERS JUST NORTH OF THE KC METRO AREA WITH A FEW ADDITIONAL SHOWERS TRAILING BACK FURTHER WEST TOWARDS TOPEKA. THIS ACTIVITY APPEARS TO BE ASSOCIATED WITH A WEAK DISTURBANCE NEAR H7 AS NOTED VIA RUC MOISTURE PROG. AS THIS SPREADS EASTWARD...MAY SEE A FEW ADDITIONAL SHOWERS DEVELOP ACROSS NE KS AND NW MO THROUGH THE REMAINDER OF THE AFTERNOON. STATIONARY FRONTAL BOUNDARY NOW LOCATED NEAR OR JUST NORTH OF THE MO/IA BORDER THIS AFTERNOON WITH SOME BREAKS IN THE CLOUD DECK NOTED VIA VIS SATELLITE NEAR THE BOUNDARY. MODEL CONSENSUS KEEPS HIGHEST QPF CLOSER TO THE FRONT OVERNIGHT COINCIDENT WITH HIGHER LOW LEVEL MOISTURE CONTENT AND SOMEWHAT STRONGER 295-300K ISENTROPIC ASCENT. HOWEVER...APPEARS CORE OF LLJ WILL REMAIN SOUTH AND WEST OF THE AREA ACROSS THE SOUTHERN PLAINS WITH AFOREMENTIONED BOUNDARY MORE DIFFUSE OVERNIGHT. NONETHELESS...HAVE EDGED POPS UP ACROSS THE AREA WITH HIGHER AMOUNTS ACROSS THE NORTHERN COUNTIES...ALTHOUGH CONFIDENCE IS NOT HIGH WITH REGARDS TO PRECIP PLACEMENT. ATTENTION THEN TURNS TO MAIN UPPER LEVEL LOW AS IT EJECTS ACROSS THE CENTRAL PLAINS THIS WEEKEND. TOUGH TO GAGE PRECIP EPISODES WITH SEVERAL WAVES EMBEDDED WITHIN SOUTHWESTERLY FLOW. 60KT H5 JET PROGGED TO EMERGE ACROSS CENTRAL KS TOMORROW AFTERNOON AND EVENING. BELIEVE STRONGEST CONVECTIVE ACTIVITY WILL REMAIN TO OUR WEST CLOSER TO STRONGER JET DYNAMICS. HOWEVER...DEPENDING ON AMOUNT OF HEATING RECEIVED TOMORROW AFTERNOON...CANNOT RULE OUT THUNDERSTORM ACTIVITY DEVELOPING ALONG AND SOUTH OF OLD BOUNDARY. UPPER LOW TO THEN SWING INTO NORTH CENTRAL NE AND SOUTH CENTRAL SD BY SUNDAY MORNING. MODELS DIFFER A BIT ON PLACEMENT OF JET DURING THE AFTERNOON. HOWEVER...APPEARS JET AXIS WILL ALIGN FROM CENTRAL IA SOUTHWARD INTO NORTHERN MISSOURI. AS THIS OCCURS...DRYLINE WILL PUSH INTO EASTERN KS DURING THE AFTERNOON SUNDAY AND ACT AS THE FOCUS FOR THUNDERSTORM DEVELOPMENT. STILL A BIT FAR OUT...BUT IF DYNAMICS COME TOGETHER AND SUFFICIENT THERMODYNAMICS ARE REALIZED...SOME SEVERE ACTIVITY WILL BE POSSIBLE. OTHERWISE...WILL CONTINUE WITH WARM MOIST PATTERN AS SOUTHERN FLOW CONTINUES WITH THE BOUNDARY REMAINING TO THE NORTH. DEROCHE EXTENDED DISCUSSION (MON THROUGH FRI)... THE UNSETTLED WEATHER PATTERN LOOKS TO PERSIST THROUGH NEXT WEEK. SEGMENTS OF THE MID/UPPER TROUGH WILL CONTINUE TO EJECT NORTHEAST OVER THE EASTERN RIDGE EARLY NEXT WEEK. MEANWHILE THE ASSOCIATED MID/UPPER WEAKNESS WILL TRACK EAST ACROSS THE SOUTHERN/GULF STATES. THE FORECAST AREA WILL BE BETWEEN THESE TWO PORTIONS OF THE UPPER SYSTEM...WITH RELATIVELY WEAK/ELONGATED SHORTWAVE ENERGY ADVANCING ACROSS THE AREA. AS A RESULT...HAVE CONTINUED LOW END SHOWER AND THUNDERSTORM CHANCES ON MONDAY OF NEXT WEEK. UNSEASONABLY WARM TEMPERATURES WILL CONTINUE THROUGH MID WEEK NEXT WEEK...WITH SHORTWAVE RIDGING PROGRESSING ACROSS THE MIDWEST. ANOTHER MID/UPPER TROUGH WILL ENTER THE WESTERN CONUS EARLY NEXT WEEK...AND IS EXPECTED TO EVENTUALLY LIFT NORTHEAST ACROSS THE ROCKIES AND TOWARD THE NORTHERN PLAINS. THE ATTENDANT SURFACE COLD FRONT IS FORECAST TO REACH THIS FORECAST AREA LATE WEDNESDAY INTO THURSDAY...AND BRING AN INCREASED CHANCE FOR MORE SHOWER AND THUNDERSTORM ACTIVITY. STOFLET AVIATION... MOST OF THE MORNING SHOWER ACTIVITY HAS EXITED THE TAF SITES AND IS NOW MAINLY CONFINED ALONG AND SOUTH OF A PLEASANTON TO SEDALIA LINE. OTHER CONCERN IS WITH LOW CLOUD DECK EXTENDING FROM SOUTHEAST KS INTO NORTHEAST MISSOURI. WITH FETCH OF LOW LEVEL MOISTURE CONTINUING THROUGH THE EARLY AFTERNOON...CURRENT THINKING IS THAT CLOUD DECK SHOULD STICK AROUND THROUGH THE SHORT TERM. DAYTIME HEATING HAS ALLOWED SOME BREAKS FURTHER NORTH ACROSS NORTHEAST KS AND SOUTHEAST NB WITH HIGHER CEILINGS ACROSS NORTHERN MO. THEREFORE...DECIDED TO BRING IN A BIT HIGHER CEILINGS BY MID AFTERNOON AS SOME MIXING TAKES SHAPE. HOWEVER...WILL HAVE TO KEEP AN EYE ON THINGS AS VARIANCE OF CLOUD DECK AND EXTENT OF MIXING REMAINS IN QUESTION. IN ADDITION...FAIRLY ACTIVE PATTERN COUNTING WITH CONTINUING DIFFICULTY IN PINPOINTING EXACT TIMING OF PRECIP. LEFT MENTION OUT ATTM WITH LOW CONFIDENCE AND WILL CONTINUE TO MONITOR FOR ANY UPSTREAM DEVELOPMENT. HOWEVER...CURRENT THINKING IS THAT PRECIP CHANCES WILL REMAIN LOW THROUGH THE REMAINDER OF THE AFTERNOON AND EVENING WITH HIGHER CHANCES DEVELOPING DURING THE MORNING HOURS. DEROCHE && .EAX WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. $$ mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPRINGFIELD MO 215 PM CDT FRI MAR 23 2007 .DISCUSSION... CONVECTION CONTINUES TO EXPAND WITH THE ORIENTATION SHIFTING MORE WEST TO EAST. DECENT LOW LEVEL MOISTURE TRANSPORT CONTINUES TO FEED INTO BROAD DIFFLUENCE ALOFT AHEAD OF A MID LEVEL SHEAR AXIS. ORIGINATION POINT OF CONVECTION IN SE KS/NE OK HAS SHIFTED VERY LITTLE OVER THE PAST SEVERAL HOURS. WHAT WAS ONCE A SW TO NE ORIENTATION HAS SHIFTED A BIT MORE TOWARDS A W-E AXIS...PARTIALLY DUE TO A SLIGHT VEER IN THE 925/850MB WIND DIRECTIONS PER THE LATEST RUC INITIALIZATIONS. PRECIPITATION CHANCES TONIGHT WILL BE TIED MAINLY TO THE EVOLUTION AND MOVEMENT OF THE ONGOING CONVECTION. GIVEN MOIST ENVIRONMENT... GOOD SUPPORT ALOFT GIVEN UPPER DIFFLUENCE AND THE MID LEVEL SHEAR AXIS...HAVE OPTED TO EXPAND CATEGORICAL POPS EASTWARD AND NORTHWARD. GAGAN/FOSTER NOT MUCH CHANGE IN THE OVERALL PATTERN AS WE HEAD INTO THE WEEKEND. OUR REGION WILL REMAIN UNDER THE INFLUENCE OF A DEEP SOUTHWESTERLY FLOW BETWEEN AN UPPER RIDGE ANCHORED OVER THE SOUTHEASTERN U.S. AND CUT OFF LOW OVER THE DESERT SOUTHWEST. THE UPPER LOW IN THE SOUTHWEST U.S. WILL LIFT NORTH NORTHEAST AROUND THE PERIPHERY OF THE RIDGE THIS WEEKEND. THIS WILL INDUCE THE DEVELOPMENT OF A SURFACE LOW ACROSS THE HIGH PLAINS. AS A RESULT A WARM FRONT WILL DEVELOP OR STRENGTHEN WHICH WE MAY BE SEEING THE ORIGINS NOW ACROSS SOUTHERN MISSOURI. MODELS HAVE TRENDED STRONGER WITH UPPER RIDGING INTO THE OZARKS THIS WEEKEND AND THUS KEEP PRECIPITATION CHANCES MAINLY TO THE WEST OF THE AREA. ALL OF THE OZARKS REGION AND OSAGE PLAINS WILL BE ENVELOPED BY THE WARM SECTOR SATURDAY AND SUNDAY. MORE SUNSHINE AND INCREASING SOUTHERLY FLOW SHOULD PUSH TEMPERATURES TO AROUND 80 DEGREES. IF NEAR FULL SUNSHINE DEVELOPS WOULD NOT BE SURPRISED TO SEE LOWER OR EVEN MIDDLE 80S IN A FEW SPOTS. NEXT IN SERIES OF SHORTWAVES WILL LIFT NORTHEAST TOWARD THE AREA EARLY NEXT WEEK PROVIDING A CHANCE OF SCATTERED CONVECTION. BETTER CHANCES OF THUNDERSTORMS WILL ARRIVE LATER WEDNESDAY OR THURSDAY OF NEXT WEEK AS A MORE SIGNIFICANT UPPER TROUGH SWINGS EAST ACROSS THE ROCKIES. FOSTER && .AVIATION... FOR THE 18Z TAF PACKAGE...PRIMARY CONCERNS REVOLVE AROUND CONVECTION FOR THIS AFTERNOON. RAINFALL HAS QUICKLY EXPANDED EASTWARD...COMING IN ABOUT AN HOUR EARLIER THAN EXPECTED AT SGF. RADAR TRENDS AND SHORT TERM FORECAST GUIDANCE SUGGESTS THAT THE CORRIDOR FROM JLN TO SGF WILL BE IN FOR A WET AFTERNOON. PERIODS OF SHRA/TSRA ARE EXPECTED. CIG/VIS WILL FLUCTUATE FROM VFR TO MVFR WITH THE PASSAGE OF MORE SUBSTANTIAL CELLS/DOWNPOURS. FREQUENT LIGHTNING IS ALSO EXPECTED. TIMING THE ENDING OF THIS RAINFALL IS PROVING PROBLEMATIC AND HAVE KEPT PREDOMINATE TSRA AT BOTH JLN AND SGF THROUGH THE LATE AFTERNOON. WILL MONITOR RADAR TRENDS TO SEE IF THE WEST TO EAST AXIS OF SHRA/TSRA BEGINS TO SHIFT NORTH/EAST. AFTER THE RAIN ENDS...GENERALLY VFR CONDITIONS ARE EXPECTED. SUBSEQUENT TAFS WILL NEED TO MONITOR THE POTENTIAL FOR LIGHT FOG IN THE WAKE OF THIS RAINFALL. AT THIS POINT...CONTINUED 30-40KT WINDS IN THE LOW LEVELS JUST OFF THE SFC WOULD LIKELY PRECLUDE THIS FROM OCCURRING. GUSTY WINDS ARE EXPECTED TO DEVELOP SATURDAY MORNING AS MIXING BEGINS. GAGAN && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. $$ WFO SGF mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPRINGFIELD MO 1245 PM CDT FRI MAR 23 2007 .UPDATE... CONVECTION CONTINUES TO EXPAND WITH THE ORIENTATION SHIFTING MORE WEST TO EAST. HAVE ONCE AGAIN UPDATED THE FORECAST TO ACCOUNT FOR THE LATEST RADAR TRENDS. DECENT LOW LEVEL MOISTURE TRANSPORT CONTINUES TO FEED INTO BROAD DIFFLUENCE ALOFT AHEAD OF A MID LEVEL SHEAR AXIS. ORIGINATION POINT OF CONVECTION IN SE KS/NE OK HAS SHIFTED VERY LITTLE OVER THE PAST SEVERAL HOURS. WHAT WAS ONCE A SW TO NE ORIENTATION HAS SHIFTED A BIT MORE TOWARDS A W-E AXIS...PARTIALLY DUE TO A SLIGHT VEER IN THE 925/850MB WIND DIRECTIONS PER THE LATEST RUC INITIALIZATIONS. THE HEAVIEST RAINFALL CONTINUES FROM CHEROKEE COUNTY INTO LAWRENCE COUNTY. STREET FLOODING HAS BEEN REPORTED IN THE PAST HALF HOUR VIA CHEROKEE EMERGENCY MGMT AND WITH HEAVY RAINFALL CONTINUING FOR THE NEXT FEW HOURS REPORTS SUCH AS THESE ARE EXPECTED TO INCREASE. WILL ALTER ORIENTATION OF POTENTIAL FLOODING IN THE HWO WITH THE 100PM ISSUANCE TO INCLUDE AREAS FROM CHEROKEE COUNTY THROUGH GREENE COUNTY WITH HEAVY RAINFALL ELSEWHERE. GIVEN MOIST ENVIRONMENT...GOOD SUPPORT ALOFT GIVEN UPPER DIFFLUENCE AND THE MID LEVEL SHEAR AXIS...HAVE OPTED TO EXPAND CATEGORICAL POPS EASTWARD. LOOKS LIKE A WET AFTERNOON. GAGAN && .PREVIOUS DISCUSSION... //1055 AM CDT FRI MAR 23 2007// FORECAST UPDATED TO ACCOUNT FOR THE LATEST RADAR TRENDS. AXIS OF SHRA/TSRA HAS DEVELOPED ALONG A MID/UPPER LEVEL SHEAR AXIS EXTENDING FROM NE MO THROUGH SE KS AND INTO NE TX. DECENT MOISTURE TRANSPORT IS NOTED IN THE LOW LEVELS OF THE ATMOSPHERE...WITH THETA-E RIDGING TO THE TUNE OF 328K NOSING INTO WEST CENTRAL MISSOURI. THE MOST CONCENTRATED AREAS OF SHRA/TSRA CURRENTLY RESIDES OVER JASPER COUNTY MO AND CHEROKEE COUNTY MO. ADDITIONAL...MORE SCATTERED ACTIVITY EXTENDS FARTHER EAST ON THE NE PERIPHERY OF THE BEST LOW LEVEL MOISTURE TRANSPORT VECTORS (AS VIEWED THROUGH THE LATEST RUC INITIALIZATIONS). WITH PWS FROM THE MORNING KSGF SOUNDING AROUND 1.15 INCHES AND KIS IN EXCESS OF 30...THIS ACTIVITY WILL BE EFFICIENT IN RAINFALL PRODUCTION. METARS ACROSS SE KS CORRELATE WELL TO 1-HR RAINFALL RATES. WITH THE RADAR CURRENTLY INDICATING HOURLY RAINFALL AMOUNTS BETWEEN ONE AND TWO INCHES...A FLASH FLOOD THREAT EXISTS. THE PRIMARY CONCERN REMAINS EXTREME SE KS AND WESTERN MO WHERE FLASH FLOOD GUIDANCE VALUES REMAIN LOW FROM RECENT RAINS. INDICATIONS ARE THAT WHILE THIS AREA OF RAINFALL WILL REMAIN ELONGATED AND RATHER NARROW...THE SLOW MOVEMENT OF THE SHEAR AXIS WILL PROMOTE TRAINING CONVECTION IN AN AREA WITH LOWER TOLERANCE FOR HEAVY RAINFALL AMOUNTS. ALL PRODUCTS HAVE BEEN UPDATED AND SENT. && .AVIATION... FOR THE 18Z TAF PACKAGE...PRIMARY CONCERNS REVOLVE AROUND CONVECTION FOR THIS AFTERNOON. RAINFALL HAS QUICKLY EXPANDED EASTWARD...COMING IN ABOUT AN HOUR EARLIER THAN EXPECTED AT SGF. RADAR TRENDS AND SHORT TERM FORECAST GUIDANCE SUGGESTS THAT THE CORRIDOR FROM JLN TO SGF WILL BE IN FOR A WET AFTERNOON. PERIODS OF SHRA/TSRA ARE EXPECTED. CIG/VIS WILL FLUCTUATE FROM VFR TO MVFR WITH THE PASSAGE OF MORE SUBSTANTIAL CELLS/DOWNPOURS. FREQUENT LIGHTNING IS ALSO EXPECTED. TIMING THE ENDING OF THIS RAINFALL IS PROVING PROBLEMATIC AND HAVE KEPT PREDOMINATE TSRA AT BOTH JLN AND SGF THROUGH THE LATE AFTERNOON. WILL MONITOR RADAR TRENDS TO SEE IF THE WEST TO EAST AXIS OF SHRA/TSRA BEGINS TO SHIFT NORTH/EAST. AFTER THE RAIN ENDS...GENERALLY VFR CONDITIONS ARE EXPECTED. SUBSEQUENT TAFS WILL NEED TO MONITOR THE POTENTIAL FOR LIGHT FOG IN THE WAKE OF THIS RAINFALL. AT THIS POINT...CONTINUED 30-40KT WINDS IN THE LOW LEVELS JUST OFF THE SFC WOULD LIKELY PRECLUDE THIS FROM OCCURRING. GUSTY WINDS ARE EXPECTED TO DEVELOP SATURDAY MORNING AS MIXING BEGINS. GAGAN && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. $$ WFO SGF mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPRINGFIELD MO 1055 AM CDT FRI MAR 23 2007 .UPDATE... FORECAST UPDATED TO ACCOUNT FOR THE LATEST RADAR TRENDS. AXIS OF SHRA/TSRA HAS DEVELOPED ALONG A MID/UPPER LEVEL SHEAR AXIS EXTENDING FROM NE MO THROUGH SE KS AND INTO NE TX. DECENT MOISTURE TRANSPORT IS NOTED IN THE LOW LEVELS OF THE ATMOSPHERE...WITH THETA-E RIDGING TO THE TUNE OF 328K NOSING INTO WEST CENTRAL MISSOURI. THE MOST CONCENTRATED AREAS OF SHRA/TSRA CURRENTLY RESIDES OVER JASPER COUNTY MO AND CHEROKEE COUNTY MO. ADDITIONAL...MORE SCATTERED ACTIVITY EXTENDS FARTHER EAST ON THE NE PERIPHERY OF THE BEST LOW LEVEL MOISTURE TRANSPORT VECTORS (AS VIEWED THROUGH THE LATEST RUC INITIALIZATIONS). WITH PWS FROM THE MORNING KSGF SOUNDING AROUND 1.15 INCHES AND KIS IN EXCESS OF 30...THIS ACTIVITY WILL BE EFFICIENT IN RAINFALL PRODUCTION. METARS ACROSS SE KS CORRELATE WELL TO 1-HR RAINFALL RATES. WITH THE RADAR CURRENTLY INDICATING HOURLY RAINFALL AMOUNTS BETWEEN ONE AND TWO INCHES...A FLASH FLOOD THREAT EXISTS. THE PRIMARY CONCERN REMAINS EXTREME SE KS AND WESTERN MO WHERE FLASH FLOOD GUIDANCE VALUES REMAIN LOW FROM RECENT RAINS. INDICATIONS ARE THAT WHILE THIS AREA OF RAINFALL WILL REMAIN ELONGATED AND RATHER NARROW...THE SLOW MOVEMENT OF THE SHEAR AXIS WILL PROMOTE TRAINING CONVECTION IN AN AREA WITH LOWER TOLERANCE FOR HEAVY RAINFALL AMOUNTS. ALL PRODUCTS HAVE BEEN UPDATED AND SENT. GAGAN && .PREVIOUS DISCUSSION... //303 AM CDT FRI MAR 23 2007// THE UNSEASONABLY WARM AND UNSETTLED PATTERN WILL PERSIST THROUGH MUCH OF THE SEVEN DAY FORECAST PERIOD. UNUSUAL FOR THE TIME OF YEAR...NO COLD FRONTS OR MAJOR WEATHER SYSTEMS ARE EXPECTED TO PASS OVERHEAD. HOWEVER...DUE TO AN EXTENDED PERIOD OF GULF INFLUX...SCATTERED CLUSTERS OF SHOWERS AND THUNDERSTORMS ARE IN THE OFFING FOR THE NEXT SEVERAL DAYS. THEREFORE...THE PRIMARY FORECAST CONCERN IN THIS MORNINGS ANALYSIS WAS PRECIP CHANCES IN BOTH THE SHORT AND LONG TERM TIME FRAMES. ONE ITEM TO NOTE...BECAUSE OF EAST TO NORTHEAST FLOW OVER MUCH OF THE GULF OF MEXICO...A RATHER HOMOGENEOUS AIRMASS WILL CONTINUE FROM THE GULF INTO MID AMERICA. DRY ADVECTION FROM THE ATLANTIC REGIONS CONTINUE TO LIMIT DEEP RICH MOISTURE FROM MATERIALIZING WITHIN THE WESTERN GULF SOURCE REGION. THEREFORE...DESPITE THE LONG PERIOD OF SOUTHERLY FLOW...INSTABILITY WILL REMAIN UNUSUALLY LIMITED FOR STRONG TO SEVERE CONVECTION THE NEXT FEW DAYS. SHORT TERM (TODAY - SUNDAY NIGHT)... A SYNOPTIC SCALE CYCLONE CENTERED OVER THE BAJA OF CALIFORNIA CONTINUES TO INFLUENCE THE OVERALL PATTERN OVER THE SOUTHERN PLAINS AND MISSOURI OZARKS REGION. A BELT OF SUBTROPICAL MOISTURE EXTENDS AROUND THE EASTERN FLANK OF THE CYCLONE...AND IS CORRELATED WITH LARGE SCALE LIFT MAINLY IN THE FORM OF JET STREAM LEVEL DIFFLUENCE. A FEW CLUSTERS OF CONVECTION WITHIN THE PACIFIC MOISTURE PLUME APPEAR TO BE CORRELATED WITH ENHANCED AREAS OF UPPER LEVEL DIFFLUENCE...WHICH IS VERIFIED BY THE SOUTHERN PLAINS PROFILER NETWORK WHEN ANALYZING 250 MB WIND VECTOR MEASUREMENTS. ONE OF THESE CONVECTIVE CLUSTERS IS CURRENTLY IMPACTING EXTREME SOUTHEAST KANSAS AND SOUTHWEST MISSOURI. DUE TO LIMITED INSTABILITY...THE PRIMARY HAZARDS WITH THIS CLUSTER APPEARS TO BE MODERATE TO HEAVY RAIN...ALONG WITH A FEW CLOUD TO GROUND LIGHTNING STRIKES. TIMING OF THIS CONVECTIVE CLUSTER AND HOW IT EVOLVES WITH RESPECT TO AREAL COVERAGE WAS THE INITIAL FORECAST CONCERN FOR TODAYS PERIOD. EXTRAPOLATION WITH THE CLUSTERS CURRENT MOVEMENT SUGGESTS THAT AFTER 12Z...THE PRECIPITATION SHIELD WILL BE OVER MUCH OF SOUTH CENTRAL AND CENTRAL MISSOURI. RAIN WILL LIKELY END IN THE SPRINGFIELD METRO AREA SOMETIME BETWEEN 6 - 8AM. THEREFORE WILL ADJUST MORNING POPS TO REPRESENT THIS EXTRAPOLATION...WITH LIKELY TO CATEGORICAL POPS OVER THE EASTERN HALF OF THE CWA...THEN TAPERING THE GRID TO SLIGHT CHANCES OUT WEST. IT`S LIKELY THAT THE CLUSTER WILL LOSE SOME OF IT`S LOW LEVEL FORCING WITH NOCTURNAL VEERING OF LOW LEVEL WINDS. BOTH THE WRF AND THE GFS INDICATE A SECOND CLUSTER OF CONVECTION TO IMPACT THE OZARKS THIS AFTERNOON. AGAIN...THE ONLY KINEMATIC MECHANISM TO CAUSE THIS APPEARS TO BE AN AREA OF ENHANCED UPPER DIFFLUENCE CURRENTLY BECOMING MORE ORGANIZED NEAR ABILENE TEXAS. HOW THIS FORECASTED BAND OF FORCING WILL IMPACT THE OZARKS REMAINS VERY QUESTIONABLE. QPF FIELDS FROM THE WRF AND GFS ARE VERY INCONSISTENT AND NOT IMPRESSIVE AT ALL. HOWEVER MOS GUIDANCE SUGGEST CATEGORICAL POPS IN ALL LOCATIONS. WILL ADJUST THE AFTERNOON POP GRID TO 50 POPS DUE TO THE UNCERTAINTY ON HOW THIS EVOLVES. ONE ELEMENT THAT WE DO KNOW FOR SURE IS THAT CONSIDERABLE CLOUD COVER WILL EXIST THROUGH THE ENTIRE DAY...WHICH WILL HAVE SOME IMPACTS ON TEMPERATURES. WITH EARLY MORNING TEMPERATURES STARTING OUT IN THE LOW TO MID 60S...DESPITE CLOUD COVER AND PRECIP READINGS SHOULD WARM INTO THE 70S IN MOST LOCATIONS. HEADING INTO THE WEEKEND...THE BAJA LOW WILL FILL WHILE THE MAIN CIRCULATION SHIFTS INTO THE HIGH PLAINS. MASS AND MOISTURE FIELDS FROM THE GFS INDICATE THAT THE AXIS OF SUBTROPICAL MOISTURE SHIFTS EAST OF THE CWA...HOWEVER...LOW LEVEL JET AND WARM CONVEYOR BELT PROCESSES OCCUR BY SATURDAY MORNING. THIS WILL YIELD MORE AREAS OF CONVECTIVE CLUSTERS SOMEWHERE ALONG THE SOUTHERN/CENTRAL PLAINS CORRIDOR. RESIDUAL CLUSTERS WILL LIKELY SHIFT EASTWARD DURING THE DAY ON SATURDAY...POSSIBLY IMPACTING THE CWA. WILL KEEP ONGOING THUNDERSTORM CHANCES GOING IN THE GRIDS DUE TO SIGNALS FROM BOTH THE GFS AND WRF FOR INCREASED INSTABILITY WITHIN THIS PERIOD. NOT MUCH CHANGE IN THE LARGE SCALE PATTERN CAN BE ANALYZED WITHIN MODEL DATA. THEREFORE SINCE WE WILL REMAIN UNDER THIS EXTENDED WARM/MOISTURE ADVECTION REGIME...WILL KEEP THUNDERSTORM CHANCES GOING THROUGH SUNDAY NIGHT. LONG TERM (MONDAY - THURSDAY)... AN UPPER LEVEL WEAKNESS...BASICALLY THE RESIDUAL TROUGHING FROM THE ONGOING BAJA CYCLONE IS SUGGESTED TO GRADUALLY PASS THROUGH THE AREA MONDAY OR TUESDAY. NOT MUCH OF A RESPONSE OCCURS AT THE SURFACE AS THE OZARKS REMAINS UNDER SOUTHERN FLOW. COOLING ALOFT MAY PROMOTE INCREASED INSTABILITY...ESPECIALLY TUESDAY AFTERNOON. WILL KEEP ONGOING TSTORM CHANCES ON TUESDAY LOOK GOOD AND MADE LITTLE CHANGE. MEDIUM RANGE MODELS INDICATE THAT LONG WAVE TROUGHING WILL REDEVELOP ACROSS THE WESTERN THIRD OF THE CONUS. THIS WILL REINFORCE THE UNSETTLED PATTERN AND OFFER A CONTINUATION OF UNSEASONABLY WARM TEMPERATURES. I MADE A FEW ADJUSTMENTS TO TEMPERATURES BY WARMING THESE GRIDS BY SEVERAL DEGREES IN THE EXTENDED. ECMWF HAS BEEN PERFORMING THE BEST OVER THE PAST FEW WEEKS...WHICH SHOWS ENERGY APPROACHING THE NATIONS MID SECTION BY THURSDAY. THE GFS IS NOT MUCH DIFFERENT WITH A SIMILAR SOLUTION. THEREFORE NO ADJUSTMENTS TO THESE ONGOING THUNDERSTORM CHANCES WERE NEEDED. CRAMER && .AVIATION... TAF SITES WERE AMENDED EARLIER TO GAUGE RAINFALL/TS TIMING. IT APPEARS THAT CIGS/VIS WILL WAVER FROM VFR TO MVFR WITH THE ON AGAIN...OFF AGAIN HEAVIER CONVECTIVE ELEMENTS. RAINFALL WILL PERSIST AT JLN INTO THE EARLY AFTERNOON. AT SGF...CONFIDENCE IS A LITTLE LOWER IN TIMING DUE TO THE SLOW EASTWARD DRIFT OF CONVECTION...AN ESTIMATED TIMING IS PROVIDED IN THE LATEST TAF TARGETING THE EARLY TO MID AFTERNOON HOURS. GAGAN && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. $$ WFO SGF mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 925 PM EDT FRI MAR 23 2007 .SYNOPSIS... 1025 MB SURFACE HIGH PRESSURE WAS CENTERED OFF THE SC/NC COAST THIS EVENING AND EXTENDED WESTWARD ACROSS GA/SC. A WEAK LEE TROUGH WAS NOTED OVER THE FOOTHILLS OF NC... WITH A WEAKENING BACK DOOR COLD FRONT LOCATED OVER NORTHERN VA. A LARGE H5 RIDGE WAS NOW WELL ESTABLISHED FROM THE GULF COAST INTO THE SOUTHEASTERN U.S. BRINGING UNSEASONABLY WARM AND DRY WEATHER TO CENTRAL NC FOR EARLY SPRING. THE MAIN POLAR JET WAS DISPLACED OVER THE NORTHERN U.S. THIS EVENING... MUCH MORE TYPICAL FOR LATE SPRING OR EARLY SUMMER THAN EARLY SPRING. && .SHORT TERM /REST OF TONIGHT/... AFTER DAILY RECORD HIGHS FOR MARCH 23 WERE ESTABLISHED AT THE RALEIGH-DURHAM ASOS (83) AND GREENSBORO ASOS (81) FRIDAY AFTERNOON... THE TEMPERATURES WERE SLOW TO COOL THIS EVENING... WITH THE LIGHT SSW BREEZE AND PARTLY CLOUDY SKIES. MID EVENING TEMPERATURES RANGED FROM THE UPPER 60S TO LOWER 70S. THESE READINGS WERE 5-7 DEGREES WARMER THAN THE READINGS 24 HOURS BEFORE. IR SATELLITE DATA AND 00Z/24 MARCH UPPER AIR INFORMATION INDICATE AN INCREASE IN MOISTURE IN THE MID LEVELS AND ALOFT ESPECIALLY FROM NORTHERN NC NORTH AND WESTWARD. THE LATEST RUC AND GFS INDICATE A CONTINUED INCREASE IN HIGH LEVEL MOISTURE OVER AREAS EAST OF THE MOUNTAINS OF NC OVERNIGHT... WHICH APPEARS THAT IT IS ALREADY WELL UNDERWAY WITH THE INCREASING CIRRUS SINCE LATE AFTERNOON. THE SURFACE BACK DOOR FRONT WILL LOSE ITS PUSH EARLY SATURDAY... AND WILL REMAIN NORTH OF OUR REGION. THIS WILL KEEP CENTRAL NC IN A DRY AND UNSEASONABLY WARM WESTERLY FLOW SATURDAY. LOWS TONIGHT WILL HAVE DIFFICULTY IN THE FALLING BELOW 60... BUT THE CURRENT FORECAST OF 57-59 SEEMS REASONABLE. EXPECT CIRRUS TO INCREASE TO BRING A MOSTLY CLOUDY SKY OVERNIGHT. NO CHANGES NEEDED AT THIS TIME. -BADGETT && .PREV DISCUSSION... /ISSUED 245 PM EDT FRI MAR 23 2007/ SHORT TERM /TONIGHT THROUGH MONDAY/... UNSEASONABLY WARM CONDITIONS WILL PERSIST ACROSS CENTRAL NC TONIGHT THROUGH SATURDAY. WESTERLY FLOW BETWEEN 10000 AND 15000 FT WILL ADVECT MOISTURE INTO THE AREA AFTER 00Z SATURDAY WITH THE THICKEST/MOST EXTENSIVE CLOUD COVERAGE EXPECTED ACROSS THE NORTH OVERNIGHT INTO EARLY SATURDAY MORNING. THIS WILL RESULT IN MIN TEMPS MAINLY IN THE MID/UPPER 50S...WELL ABOVE SEASONAL NORMS. THIS LAYER OF MOISTURE WILL GRADUALLY DRY OUT SATURDAY WITH SCATTERED CLOUDS EXPECTED BY 18Z SATURDAY. LATE MARCH SUN COUPLED WITH UNSEASONABLY WARM AIRMASS AND LOW LEVEL W-SW FLOW WILL RESULT IN AFTERNOON TEMPS IN THE LOWER 80S. THE RECORD HIGH AT RDU WILL BE THREATENED (81 LAST SET IN 1978) WHILE THE RECORD HIGH AT GSO APPEARS TO BE SAFE (86 SET IN 1929). SATURDAY NIGHT THROUGH SUNDAY... BACKDOOR COLD FRONT DOMINATED BY DEEP LAYER OF NW FLOW WILL DROP SOUTH ACROSS THE FORECAST AREA BETWEEN 12 TO 18Z. WEAK FRONTAL ZONE CONVERGENCE AND INSTABILITY JUST NOT ENOUGH TO OVERCOME WARM AND STABLE MID LEVELS ON SUNDAY. CAN`T SEE MUCH MORE THAN IN THE WAY OF SPRINLES AS FRONTAL ZONE MOVES THROUGH THE AREA. WILL KEEP POPS BELOW 15%. TEMPERATURES REALLY DEPENDENT ON CLOUD COVER WITH INCREASE IN MID-LEVEL MOISTURE LATE SATURDAY NIGHT. FAVOR THE WARMER GFS THICKNESSES AND MAV MOS GUIDANCE FOR HIGHS SUNDAY AS BACKDOOR FROPA GENERALLY RESULTS IN AN INITIAL WIND SHIFT AS OPPOSE TO INSTANTANEOUS CAA. LOWS SATURDAY NIGHT UPPER 50S TO AROUND 60. HIGHS SUNDAY 77 TO 82...EXCEPT LOWER 70S IN THE NE COASTAL PLAIN. SUNDAY NIGHT THROUGH MONDAY...1034MB DRY AIR SURFACE RIDGE BUILDS SOUTH DOWN THE MID-ATLANTIC SEABOARD. FORECAST SOUNDINGS INDICATE VARYING AMOUNTS OF MID AND HIGH CLOUDS WITH LOW-LEVEL NE MARITIME FLOW SHOWING A SLOW SCATTERING OUT OF MOISTURE SUNDAY NIGHT AND INTO MONDAY MORNING. NOTICABLY COOLER MONDAY. HIGHS IN THE MID 60S UNDER NE FLOW. LONG TERM /TUESDAY THROUGH FRIDAY/... DRY AND WARM CONDITIONS TO CONTINUE. A CYCLONIC VORTEX OVER TEXAS WILL BECOME SHEARED APART AS IT PROGRESSES EAST INTO THE PERSISTENT EASTERN CONUS UPPER RIDGE. THE MEAN UPPER RIDGE UNDERGOES JUST ENOUGH DEAMPLIFICATION TO ALLOW YET ANOTHER BACK-DOOR COLD FRONT TO PUSH SOUTH INTO THE CAROLINAS. THERE IS SOME UNCERTAINTY AS TO WHETHER THERE IS ENOUGH OF A NORTHERN PUSH FROM BUILDING PARENT HIGH TO THE NORTH AS UPPER LEVEL HEIGHT RISES QUICKLY RETURN AS PACIFIC SHORTWAVE ENERGY DIGS ACROSS THE NORTHERN PLAINS. MEAN FLOW REMAINS OUT OF THE WNW...THUS PROBABILITY OF CENTRAL NC SEEING SIGNIFICANT RAINFALL CLOSE TO NIL WITH A PASSING SPRINKLE OR TWO POSSIBLE WITH BACK-DOOR FRONT LATE TUESDAY. WHILE TEMPERATURES MAY DROP A DEGREE OR TWO ON THURSDAY... POSITIVE UPPER HEIGHT ANOMALIES WILL RESULT IN ABOVE NORMAL TEMPERATURES...GENERALLY IN THE 70S FOR AFTERNOON HIGHS AND 50 TO 55 FOR OVERNIGHT LOWS. AVIATION /18Z-18Z/... FLAT RIDGE ALOFT COUPLED WITH W-E ORIENTATED RIDGE AT THE SURFACE ACROSS CENTRAL NC WILL RESULT IN VFR CONDITIONS THROUGH SATURDAY. MID LEVEL FLOW WILL ADVECT MOISTURE INTO THE REGION LATE TONIGHT...AFFECTING MAINLY THE KINT, KGSO, KRDU AND KRWI TERMINALS WITH CEILINGS BETWEEN 12000-15000 FT. NEAR SURFACE FLOW WILL BE LIGHT OUT OF THE SW TONIGHT THEN VEER TO A MORE WESTERLY COMPONENT BY MID DAY SATURDAY AS THE SURFACE RIDGE AXIS SLIDES TO THE SOUTH. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS... SHORT TERM...BADGETT nc AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE RALEIGH NC 1223 PM EDT THU MAR 22 2007 .SHORT TERM /REST OF TODAY/... MADE A QUICK LATE MORNING UPDATE TO THE GRIDDED AND WORDED FORECASTS...PRIMARILY TO REFRESH THEM. MORNING LOW CLOUDS QUICKLY DISSIPATED BETWEEN 1330Z AND 1530Z...LEAVING MOSTLY SUNNY CONDITIONS OVER CENTRAL NORTH CAROLINA. DIURNAL CUMULUS DEVELOPMENT WAS TAKING PLACE LATE IN THE MORNING TOWARD THE COASTAL PLAIN AND SANDHILLS. NAM AND RUC MODEL SOUNDINGS FOR THE AFTERNOON CORRESPOND WITH OBSERVED HIGHER LOW LEVEL MOISTURE OBSERVED IN THE COASTAL PLAIN AND SANDHILLS SUCH THAT ANTICIPATE ENOUGH CU TO PROVIDE FOR PARTLY SUNNY CONDITIONS FOR THE AFTERNOON. BOTH THE NAM AND THE RUC SUGGEST A HUNDREDTH OR TWO IN A SHOWER POSSIBLE WITH THE SEA BREEZE POSSIBLY AS FAR INLAND AS NEAR CTZ AND GSB...BUT GIVEN THE FORECAST OF 700MB SUBSIDENCE... THE BEST LOW-LEVEL CONVERGENCE FORECAST CLOSER TO THE COAST...AND MID-LEVEL CAPPING EVIDENT ON THE MODEL SOUNDINGS FOR THE AFTERNOON... HAVE OPTED TO RAISE THE GRIDDED POPS TO 10 PERCENT OVER THOSE AREAS WHILE KEEPING THE FORECAST WORDING DRY. A WEAK 700MB SHORTWAVE AS FORECAST BY THE RUC ALSO MOVES EAST DURING THE LATE AFTERNOON...AND IN ITS WAKE SUBSIDENCE MAY BE ENHANCED SLIGHTLY. WITH THE CTZ TEMPERATURE ALREADY IN THE LOWER 70S AT 11 AM SUN TIME (EST)...RAISED MAXES THERE TO NEAR 80 DEGREES. OTHERWISE... HIGHS AROUND 70 OR IN THE LOWER 70S IN THE TRIAD TO THE UPPER 70S TOWARD KFAY SHOULD WORK WELL. MAY BE A FEW GUSTS OF WIND ESPECIALLY EARLY THIS AFTERNOON AS GOOD MIXING FINALLY DEVELOPS... BUT ANTICIPATE THE STRONGER GUSTS...IF ANY...TO BE IN NORTHERN ZONES AND THEN TO 25 MPH AT BEST. LOCAL PROFILER DATA HAS SHOWN A GRADUAL DIMINISHING TREND IN THE WIND JUST ABOVE THE SURFACE THROUGH THE LATE MORNING. && .PREV DISCUSSION... /ISSUED 1046 AM EDT THU MAR 22 2007/ LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... THE MEDIUM RANGE MODELS CONTINUE TO FAVOR A LARGE AMPLITUDE RIDGE ALOFT ALONG THE EAST COAST THROUGH THE PERIOD. DETAILS OF LOWER LEVEL CONDITIONS VARY AMONGST THE MODELS RELATED TO THE EXTENT OF NORTHERN STREAM AIRMASSES SURGING SOUTH ALONG THE MID ATLANTIC COAST AT THE BEGINNING OF THE PERIOD AND AGAIN TOWARD THU. HOW MUCH OF A MARITIME INFLUENCE AND ASSOCIATED LOW LEVEL MOISTURE ON BROAD EASTERLY FLOW OFF THE ATLANTIC WILL GOVERN CLOUD COVER AND TEMPERATURES DURING THE PERIOD. OTHERWISE...CONDITIONS SHOULD REMAIN STABLE ALOFT PRECLUDING MEASURABLE RAINFALL OVER CENTRAL NC. TEMPERATURES SHOULD AVERAGE ABOVE NORMAL WITH ABOUT A 20 DEGREE DIURNAL RANGE FROM LOWS MAINLY LOWER 50S TO HIGH MAINLY LOWER 70S. -RFG PREV DISCUSSION... /ISSUED 950 AM EDT THU MAR 22 2007/ SHORT TERM /REST OF TODAY/... SURFACE HIGH PRESSURE WAS OVER CENTRAL NORTH CAROLINA THIS MORNING... BUT THERE WAS AN AXIS OF LOW-LEVEL MOISTURE WHICH...UNDER THE 25KTS OF SOUTHWEST FLOW JUST OFF OF THE SURFACE...RESULTED IN STRATUS FROM THE NORTHEAST PIEDMONT...THROUGH THE TRIAD...INTO THE WADESBORO AND ALBEMARLE AREAS. THE LATEST RUC 950MB MOISTURE PATTERN FIT THE STRATUS WELL...AND THAT FORECAST KEPT THE STRATUS ABOUT AS FAR EAST AS IT ALREADY WAS...MIXING OUT DURING THE LATE MORNING. ALREADY...A COMBINATION OF VISIBLE AND INFRARED SATELLITE IMAGES WERE SHOWING SOME EROSION NEAR ROCKINGHAM AND THIS TREND SHOULD CONTINUE FOR THE REST OF THE MORNING. CURRENTLY ANTICIPATING SKIES TO BE AT LEAST PARTLY SUNNY...IF NOT MOSTLY SUNNY...IN MOST LOCATIONS BY 17Z. MORNING KGSO RAOB SHOWS THAT...IF THE AIR BECOMES WELL MIXED... TEMPERATURES COULD RISE INTO THE MID 70S. BASED ON MORNING 12Z 1000-850MB THICKNESSES...FULL SUN WOULD SHOW LOWER 70S TOWARD KGSO. THINK THAT THE MID AND UPPER 60S FORECAST BY THE LATEST MET AND FWC MOS GUIDANCE FOR THE TRIAD MIGHT BE A LITTLE COOL...AND IF THE CLOUDS MIX OUT AS FORECAST TEMPERATURES SHOULD AT LEAST RISE TO AROUND 70 THERE. UNDER GOOD SUN...THINK THE UPPER 70S FORECAST IN PARTS OF THE SANDHILLS AND SOUTHERN COASTAL PLAIN SHOULD WORK WELL. LOWERED MAXES A COUPLE OF DEGREES MAINLY IN THE AXIS OF MOST DENSE CLOUDS FROM KRDU THROUGH KGSO AND KINT...BUT STILL LOOKING FOR READINGS WELL ABOVE SEASONAL NORMS. KGSO 12Z SOUNDING...AGAIN...SHOWED 25KT WINDS JUST OFF OF THE SURFACE AND AS MIXING OCCURS INITIALLY THERE COULD BE A GUST OR TWO AROUND 20 MPH...ESPECIALLY NORTHERN ZONES. DURING THE AFTERNOON... RUC AND THE NAM40 BOTH FORECAST DIMINISHING 925MB WINDS...MAINLY TO 10-20KTS...WITH THE STRONGER WINDS NORTH. THE NAM IS A LITTLE STRONGER THAN THE RUC...AND THE RADAR WIND PROFILES EARLY THIS MORNING LEAN TOWARD THE STRONG NAM WITH ITS HIGHER WINDS VERIFYING. OPTED TO KEEP THE MENTION OF BREEZY CONDITIONS IN NORTHERN ZONES BUT ANTICIPATE THE GRADUALLY FALLING 925MB WINDS TOWARD THE SANDHILLS AND SOUTHERN COASTAL PLAIN SHOULD KEEP SURFACE WINDS FROM GETTING TOO GUSTY THIS AFTERNOON. GRIDDED AND WORDED FORECAST UPDATES ALREADY SENT AND WILL ISSUE ANOTHER UPDATE AROUND THE NOON HOUR TO REMOVE MORNING WORDING AND REFRESH THE GRIDDED AND GRAPHICAL FORECASTS. -DJF PREV DISCUSSION... /ISSUED 220 AM EDT THU MAR 22 2007/ SYNOPSIS... 1035 MB SURFACE HIGH WAS CENTERED WELL OFFSHORE OF NEW ENGLAND EARLY THURSDAY. THE RIDGE AXIS EXTENDED SW OVER CENTRAL NC INTO NE GA... WITH A RESIDUAL COOL STABLE AIR MASS OVER MUCH OF CENTRAL NC. STRONG WAA WAS OCCURRING JUST WEST OF THE APPALACHIANS. THE SURFACE HIGH WILL MOVE FARTHER EAST TODAY AND THE RIDGE AXIS WILL SHIFT EAST AND SOUTH OF OUR REGION AS WELL. THIS WILL ALLOW WAA TO OVERSPREAD CENTRAL NC TODAY... DISLODGING THE RESIDUAL COOL STABLE AIR MASS BY LATE MORNING. THE FORECAST PROBLEM LATER TODAY THROUGH THE WEEKEND WILL BE HOW WARM THE TEMPERATURES GO AS THE UPPER RIDGE BUILDS TO OUR SW RAISING HEIGHTS... THE MEAN LOW LEVEL FLOW BECOMES WESTERLY... AND THE LOW LEVEL THICKNESSES RISE. SHORT TERM /TODAY THROUGH SUNDAY NIGHT/... THE FIRST PART OF TODAY WILL BE A BIT PROBLEMATIC FOR AMOUNT OF CLOUDS AND EXTENT OF LOW CEILINGS (CIGS). THE MODELS HAVE DONE A POOR JOB INITIALIZING THE CURRENT WEAK COOL AIR DAMMING EVENT. MODELS HAVE BEEN MUCH TOO MOIST IN DEPICTING WIDESPREAD LOW CLOUDS DURING THE PAST 24 HOURS... WHICH DID NOT OCCUR. THE 00Z/22 MARCH RAOBS INDICATED THAT THE BOUNDARY LAYER NEVER BECAME FULLY SATURATED... EVEN OVER THE TYPICAL DAMMING REGION... LIKELY DUE IN PART TO THE LACK OF ANY REAL MEASURABLE RAINFALL. THEREFORE... WE ARE CURRENTLY EXPERIENCING VARIABLE AMOUNTS OF CLOUDINESS WITH MANY AREAS ACTUALLY PARTLY CLOUDY OR MOSTLY CLEAR. WHILE THERE WERE PATCHES OF LOW CLOUDS ESPECIALLY OVER THE PIEDMONT... THERE WERE ONLY MID CLOUDS OBSERVED DOWN EAST AT 06Z/22. THE MOST EXTENSIVE LOW CLOUD DECK IS EXPECTED OVER THE WEST AND NORTH PIEDMONT THROUGH 15Z OR SO. GUIDANCE STILL FORECASTS NEAR SATURATION OF THE BOUNDARY LAYER THROUGH DAYBREAK IN THESE AREAS... WHICH APPEARS LIKELY GIVEN THE RAPIDLY VEERING WINDS IN THE LOWEST 5K FEET SEEN ON THE LATEST VAD... RAOBS... AND FORECAST SOUNDINGS. THIS WILL CONTINUE TO BRING WAA FROM THE S-SW OVER TOP THE COOL STABLE DOME (PIEDMONT AND NORTHERN COASTAL PLAIN PRODUCING BROKEN TO OVERCAST SKIES WITH CIGS BETWEEN 1000 AND 1500 FEET. PARTLY CLOUDY SKIES ARE EXPECTED OVER THE SANDHILLS AND SOUTHERN COASTAL PLAIN... WHERE SOME PATCHY FOG WILL BE POSSIBLE AS THE T/TD SPREAD NARROWS TO LESS THAN 5 DEGREES F BEFORE DAYBREAK. AS THE SURFACE RIDGE ALOFT MOVES OUT THIS MORNING... THE WAA WILL MIX TO THE SURFACE WITH HEATING MID TO LATE MORNING. THIS WILL ALLOW THE WEAK DAMMING EVENT TO SCOUR OUR RAPIDLY. EXPECT THE SKIES TO BECOME MOSTLY SUNNY BY EARLY AFTERNOON. THE WARMER GFS MOS IS SUPPORTED BY THE LOW LEVEL THICKNESS AND AMOUNT OF SUN EXPECTED. WE WILL GO A CATEGORY ABOVE THE GFS MOS AND FORECAST HIGHS WELL INTO THE 70S TODAY. SW WINDS WILL INCREASE TO BETWEEN 10 AND 20 MPH. TONIGHT THROUGH THE WEEKEND... EXPECT A WARM AND DRY PERIOD AS THE UPPER HEIGHTS BUILD... THE H5 RIDGE DEVELOPS TO OUR SW... AND THE FLOW IN THE BOUNDARY LAYER INCREASES FROM THE WEST. A WEAK BACK DOOR FRONT MAY TRY TO EDGE INTO NE NC SATURDAY... BUT A PROGRESSIVE AND RATHER WEAK SURFACE HIGH TO THE NORTH DOES NOT SUPPORT MUCH PUSH THIS FAR SOUTH. ANOTHER BACK DOOR FRONT (STRONGER) SHOULD ARRIVE SUNDAY. THIS WOULD BACK DAYTIME TEMPS MAYBE 10 DEGREES ACROSS THE NE SECTIONS... DEPENDING ON TIMING AND LOCATION. THERE MAY BE SOME INCREASE IN HIGH CLOUDINESS ESPECIALLY NORTHERN AREAS OVER THE WEEKEND... BUT A DRY FORECAST WILL CONTINUE. TEMPS TONIGHT THROUGH THE WEEKEND WILL BE WELL ABOVE NORMAL... (BY 15 TO 20 DEGREES THIS PERIOD). LOWS TONIGHT 52-57... HIGHS FRIDAY 80-85... LOWS FRIDAY NIGHT 55-60... AND HIGHS SATURDAY 80-85. SUNDAY HIGHS OF 74-84 EXPECTED NE TO SW... AND WILL NEED TO BE FINE TUNED LATER. -BADGETT LONG TERM /MONDAY THROUGH WEDNESDAY/... PATTERN FIRST HALF OF NEXT WEEK WILL BE SIMILAR TO THAT OF TODAY... AS HIGH PRESSURE NOSES INTO SOUTH MID ATLC REGION...GRADUALLY SHIFTING OFFSHORE BY MID WEEK. THUS NORTHEAST/EAST FLOW WILL SHIFT AROUND TO SOUTH/SOUTHWEST LATE TUESDAY INTO WEDNESDAY. THIS WILL GENERATE A FAIR AMOUNT OF CLOUDS THROUGH THE PERIOD. WILL CONTINUE PARTLY CLOUDY SKIES BUT WILL INCREASE SKY PERCENTAGES IN GRIDS. CONTINUE ABOVE NORMAL TEMPERATURES... BUT NOT AS WARM AS THIS WEEKEND. -RA AVIATION /05Z-24Z/... MOIST ONSHORE FLOW HAS RESULTED IN CONSIDERABLE STRATOCU OVER WESTERN SECTIONS. THUS MVFR CIGS---1-3KFT AT INT-GSO TAF SITES. EXPECT MVFR CIGS TO GRADUALLY OVERSPREAD REMAINDER OF TAF SITES 08Z-09Z. AFTER 09Z THROUGH 13Z AREAS OF CIGS AT OR BELOW 1KFT VSBYS 3-5 MILES IN FOG. AFTER 14Z EXPECT STRATUS/STRATOCU LAYERS TO MIX OUT BECOMING SCATTERED TO BKN LAYERS 4-6KFT VSBYS UNRESTRICTED. VFR CONDITIONS AT ALL TAF SITES AFTER 16Z. LIGHT AND VARIABLE WINDS THROUGH 13Z THEN BECOMING SOUTHWEST 10 TO 15 MPH. -RA && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...DJF nc AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE RALEIGH NC 1046 AM EDT THU MAR 22 2007 .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... THE MEDIUM RANGE MODELS CONTINUE TO FAVOR A LARGE AMPLITUDE RIDGE ALOFT ALONG THE EAST COAST THROUGH THE PERIOD. DETAILS OF LOWER LEVEL CONDITIONS VARY AMONGST THE MODELS RELATED TO THE EXTENT OF NORTHERN STREAM AIRMASSES SURGING SOUTH ALONG THE MID ATLANTIC COAST AT THE BEGINNING OF THE PERIOD AND AGAIN TOWARD THU. HOW MUCH OF A MARITIME INFLUENCE AND ASSOCIATED LOW LEVEL MOISTURE ON BROAD EASTERLY FLOW OFF THE ATLANTIC WILL GOVERN CLOUD COVER AND TEMPERATURES DURING THE PERIOD. OTHERWISE...CONDITIONS SHOULD REMAIN STABLE ALOFT PRECLUDING MEASURABLE RAINFALL OVER CENTRAL NC. TEMPERATURES SHOULD AVERAGE ABOVE NORMAL WITH ABOUT A 20 DEGREE DIURNAL RANGE FROM LOWS MAINLY LOWER 50S TO HIGH MAINLY LOWER 70S. -RFG && .PREV DISCUSSION... /ISSUED 950 AM EDT THU MAR 22 2007/ SHORT TERM /REST OF TODAY/... SURFACE HIGH PRESSURE WAS OVER CENTRAL NORTH CAROLINA THIS MORNING... BUT THERE WAS AN AXIS OF LOW-LEVEL MOISTURE WHICH...UNDER THE 25KTS OF SOUTHWEST FLOW JUST OFF OF THE SURFACE...RESULTED IN STRATUS FROM THE NORTHEAST PIEDMONT...THROUGH THE TRIAD...INTO THE WADESBORO AND ALBEMARLE AREAS. THE LATEST RUC 950MB MOISTURE PATTERN FIT THE STRATUS WELL...AND THAT FORECAST KEPT THE STRATUS ABOUT AS FAR EAST AS IT ALREADY WAS...MIXING OUT DURING THE LATE MORNING. ALREADY...A COMBINATION OF VISIBLE AND INFRARED SATELLITE IMAGES WERE SHOWING SOME EROSION NEAR ROCKINGHAM AND THIS TREND SHOULD CONTINUE FOR THE REST OF THE MORNING. CURRENTLY ANTICIPATING SKIES TO BE AT LEAST PARTLY SUNNY...IF NOT MOSTLY SUNNY...IN MOST LOCATIONS BY 17Z. MORNING KGSO RAOB SHOWS THAT...IF THE AIR BECOMES WELL MIXED... TEMPERATURES COULD RISE INTO THE MID 70S. BASED ON MORNING 12Z 1000-850MB THICKNESSES...FULL SUN WOULD SHOW LOWER 70S TOWARD KGSO. THINK THAT THE MID AND UPPER 60S FORECAST BY THE LATEST MET AND FWC MOS GUIDANCE FOR THE TRIAD MIGHT BE A LITTLE COOL...AND IF THE CLOUDS MIX OUT AS FORECAST TEMPERATURES SHOULD AT LEAST RISE TO AROUND 70 THERE. UNDER GOOD SUN...THINK THE UPPER 70S FORECAST IN PARTS OF THE SANDHILLS AND SOUTHERN COASTAL PLAIN SHOULD WORK WELL. LOWERED MAXES A COUPLE OF DEGREES MAINLY IN THE AXIS OF MOST DENSE CLOUDS FROM KRDU THROUGH KGSO AND KINT...BUT STILL LOOKING FOR READINGS WELL ABOVE SEASONAL NORMS. KGSO 12Z SOUNDING...AGAIN...SHOWED 25KT WINDS JUST OFF OF THE SURFACE AND AS MIXING OCCURS INITIALLY THERE COULD BE A GUST OR TWO AROUND 20 MPH...ESPECIALLY NORTHERN ZONES. DURING THE AFTERNOON... RUC AND THE NAM40 BOTH FORECAST DIMINISHING 925MB WINDS...MAINLY TO 10-20KTS...WITH THE STRONGER WINDS NORTH. THE NAM IS A LITTLE STRONGER THAN THE RUC...AND THE RADAR WIND PROFILES EARLY THIS MORNING LEAN TOWARD THE STRONG NAM WITH ITS HIGHER WINDS VERIFYING. OPTED TO KEEP THE MENTION OF BREEZY CONDITIONS IN NORTHERN ZONES BUT ANTICIPATE THE GRADUALLY FALLING 925MB WINDS TOWARD THE SANDHILLS AND SOUTHERN COASTAL PLAIN SHOULD KEEP SURFACE WINDS FROM GETTING TOO GUSTY THIS AFTERNOON. GRIDDED AND WORDED FORECAST UPDATES ALREADY SENT AND WILL ISSUE ANOTHER UPDATE AROUND THE NOON HOUR TO REMOVE MORNING WORDING AND REFRESH THE GRIDDED AND GRAPHICAL FORECASTS. -DJF PREV DISCUSSION... /ISSUED 220 AM EDT THU MAR 22 2007/ SYNOPSIS... 1035 MB SURFACE HIGH WAS CENTERED WELL OFFSHORE OF NEW ENGLAND EARLY THURSDAY. THE RIDGE AXIS EXTENDED SW OVER CENTRAL NC INTO NE GA... WITH A RESIDUAL COOL STABLE AIR MASS OVER MUCH OF CENTRAL NC. STRONG WAA WAS OCCURRING JUST WEST OF THE APPALACHIANS. THE SURFACE HIGH WILL MOVE FARTHER EAST TODAY AND THE RIDGE AXIS WILL SHIFT EAST AND SOUTH OF OUR REGION AS WELL. THIS WILL ALLOW WAA TO OVERSPREAD CENTRAL NC TODAY... DISLODGING THE RESIDUAL COOL STABLE AIR MASS BY LATE MORNING. THE FORECAST PROBLEM LATER TODAY THROUGH THE WEEKEND WILL BE HOW WARM THE TEMPERATURES GO AS THE UPPER RIDGE BUILDS TO OUR SW RAISING HEIGHTS... THE MEAN LOW LEVEL FLOW BECOMES WESTERLY... AND THE LOW LEVEL THICKNESSES RISE. SHORT TERM /TODAY THROUGH SUNDAY NIGHT/... THE FIRST PART OF TODAY WILL BE A BIT PROBLEMATIC FOR AMOUNT OF CLOUDS AND EXTENT OF LOW CEILINGS (CIGS). THE MODELS HAVE DONE A POOR JOB INITIALIZING THE CURRENT WEAK COOL AIR DAMMING EVENT. MODELS HAVE BEEN MUCH TOO MOIST IN DEPICTING WIDESPREAD LOW CLOUDS DURING THE PAST 24 HOURS... WHICH DID NOT OCCUR. THE 00Z/22 MARCH RAOBS INDICATED THAT THE BOUNDARY LAYER NEVER BECAME FULLY SATURATED... EVEN OVER THE TYPICAL DAMMING REGION... LIKELY DUE IN PART TO THE LACK OF ANY REAL MEASURABLE RAINFALL. THEREFORE... WE ARE CURRENTLY EXPERIENCING VARIABLE AMOUNTS OF CLOUDINESS WITH MANY AREAS ACTUALLY PARTLY CLOUDY OR MOSTLY CLEAR. WHILE THERE WERE PATCHES OF LOW CLOUDS ESPECIALLY OVER THE PIEDMONT... THERE WERE ONLY MID CLOUDS OBSERVED DOWN EAST AT 06Z/22. THE MOST EXTENSIVE LOW CLOUD DECK IS EXPECTED OVER THE WEST AND NORTH PIEDMONT THROUGH 15Z OR SO. GUIDANCE STILL FORECASTS NEAR SATURATION OF THE BOUNDARY LAYER THROUGH DAYBREAK IN THESE AREAS... WHICH APPEARS LIKELY GIVEN THE RAPIDLY VEERING WINDS IN THE LOWEST 5K FEET SEEN ON THE LATEST VAD... RAOBS... AND FORECAST SOUNDINGS. THIS WILL CONTINUE TO BRING WAA FROM THE S-SW OVER TOP THE COOL STABLE DOME (PIEDMONT AND NORTHERN COASTAL PLAIN PRODUCING BROKEN TO OVERCAST SKIES WITH CIGS BETWEEN 1000 AND 1500 FEET. PARTLY CLOUDY SKIES ARE EXPECTED OVER THE SANDHILLS AND SOUTHERN COASTAL PLAIN... WHERE SOME PATCHY FOG WILL BE POSSIBLE AS THE T/TD SPREAD NARROWS TO LESS THAN 5 DEGREES F BEFORE DAYBREAK. AS THE SURFACE RIDGE ALOFT MOVES OUT THIS MORNING... THE WAA WILL MIX TO THE SURFACE WITH HEATING MID TO LATE MORNING. THIS WILL ALLOW THE WEAK DAMMING EVENT TO SCOUR OUR RAPIDLY. EXPECT THE SKIES TO BECOME MOSTLY SUNNY BY EARLY AFTERNOON. THE WARMER GFS MOS IS SUPPORTED BY THE LOW LEVEL THICKNESS AND AMOUNT OF SUN EXPECTED. WE WILL GO A CATEGORY ABOVE THE GFS MOS AND FORECAST HIGHS WELL INTO THE 70S TODAY. SW WINDS WILL INCREASE TO BETWEEN 10 AND 20 MPH. TONIGHT THROUGH THE WEEKEND... EXPECT A WARM AND DRY PERIOD AS THE UPPER HEIGHTS BUILD... THE H5 RIDGE DEVELOPS TO OUR SW... AND THE FLOW IN THE BOUNDARY LAYER INCREASES FROM THE WEST. A WEAK BACK DOOR FRONT MAY TRY TO EDGE INTO NE NC SATURDAY... BUT A PROGRESSIVE AND RATHER WEAK SURFACE HIGH TO THE NORTH DOES NOT SUPPORT MUCH PUSH THIS FAR SOUTH. ANOTHER BACK DOOR FRONT (STRONGER) SHOULD ARRIVE SUNDAY. THIS WOULD BACK DAYTIME TEMPS MAYBE 10 DEGREES ACROSS THE NE SECTIONS... DEPENDING ON TIMING AND LOCATION. THERE MAY BE SOME INCREASE IN HIGH CLOUDINESS ESPECIALLY NORTHERN AREAS OVER THE WEEKEND... BUT A DRY FORECAST WILL CONTINUE. TEMPS TONIGHT THROUGH THE WEEKEND WILL BE WELL ABOVE NORMAL... (BY 15 TO 20 DEGREES THIS PERIOD). LOWS TONIGHT 52-57... HIGHS FRIDAY 80-85... LOWS FRIDAY NIGHT 55-60... AND HIGHS SATURDAY 80-85. SUNDAY HIGHS OF 74-84 EXPECTED NE TO SW... AND WILL NEED TO BE FINE TUNED LATER. -BADGETT LONG TERM /MONDAY THROUGH WEDNESDAY/... PATTERN FIRST HALF OF NEXT WEEK WILL BE SIMILAR TO THAT OF TODAY... AS HIGH PRESSURE NOSES INTO SOUTH MID ATLC REGION...GRADUALLY SHIFTING OFFSHORE BY MID WEEK. THUS NORTHEAST/EAST FLOW WILL SHIFT AROUND TO SOUTH/SOUTHWEST LATE TUESDAY INTO WEDNESDAY. THIS WILL GENERATE A FAIR AMOUNT OF CLOUDS THROUGH THE PERIOD. WILL CONTINUE PARTLY CLOUDY SKIES BUT WILL INCREASE SKY PERCENTAGES IN GRIDS. CONTINUE ABOVE NORMAL TEMPERATURES... BUT NOT AS WARM AS THIS WEEKEND. -RA AVIATION /05Z-24Z/... MOIST ONSHORE FLOW HAS RESULTED IN CONSIDERABLE STRATOCU OVER WESTERN SECTIONS. THUS MVFR CIGS---1-3KFT AT INT-GSO TAF SITES. EXPECT MVFR CIGS TO GRADUALLY OVERSPREAD REMAINDER OF TAF SITES 08Z-09Z. AFTER 09Z THROUGH 13Z AREAS OF CIGS AT OR BELOW 1KFT VSBYS 3-5 MILES IN FOG. AFTER 14Z EXPECT STRATUS/STRATOCU LAYERS TO MIX OUT BECOMING SCATTERED TO BKN LAYERS 4-6KFT VSBYS UNRESTRICTED. VFR CONDITIONS AT ALL TAF SITES AFTER 16Z. LIGHT AND VARIABLE WINDS THROUGH 13Z THEN BECOMING SOUTHWEST 10 TO 15 MPH. -RA && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ LONG TERM...RFG nc AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE RALEIGH NC 950 AM EDT THU MAR 22 2007 .SHORT TERM /REST OF TODAY/... SURFACE HIGH PRESSURE WAS OVER CENTRAL NORTH CAROLINA THIS MORNING... BUT THERE WAS AN AXIS OF LOW-LEVEL MOISTURE WHICH...UNDER THE 25KTS OF SOUTHWEST FLOW JUST OFF OF THE SURFACE...RESULTED IN STRATUS FROM THE NORTHEAST PIEDMONT...THROUGH THE TRIAD...INTO THE WADESBORO AND ALBEMARLE AREAS. THE LATEST RUC 950MB MOISTURE PATTERN FIT THE STRATUS WELL...AND THAT FORECAST KEPT THE STRATUS ABOUT AS FAR EAST AS IT ALREADY WAS...MIXING OUT DURING THE LATE MORNING. ALREADY...A COMBINATION OF VISIBLE AND INFRARED SATELLITE IMAGES WERE SHOWING SOME EROSION NEAR ROCKINGHAM AND THIS TREND SHOULD CONTINUE FOR THE REST OF THE MORNING. CURRENTLY ANTICIPATING SKIES TO BE AT LEAST PARTLY SUNNY...IF NOT MOSTLY SUNNY...IN MOST LOCATIONS BY 17Z. MORNING KGSO RAOB SHOWS THAT...IF THE AIR BECOMES WELL MIXED... TEMPERATURES COULD RISE INTO THE MID 70S. BASED ON MORNING 12Z 1000-850MB THICKNESSES...FULL SUN WOULD SHOW LOWER 70S TOWARD KGSO. THINK THAT THE MID AND UPPER 60S FORECAST BY THE LATEST MET AND FWC MOS GUIDANCE FOR THE TRIAD MIGHT BE A LITTLE COOL...AND IF THE CLOUDS MIX OUT AS FORECAST TEMPERATURES SHOULD AT LEAST RISE TO AROUND 70 THERE. UNDER GOOD SUN...THINK THE UPPER 70S FORECAST IN PARTS OF THE SANDHILLS AND SOUTHERN COASTAL PLAIN SHOULD WORK WELL. LOWERED MAXES A COUPLE OF DEGREES MAINLY IN THE AXIS OF MOST DENSE CLOUDS FROM KRDU THROUGH KGSO AND KINT...BUT STILL LOOKING FOR READINGS WELL ABOVE SEASONAL NORMS. KGSO 12Z SOUNDING...AGAIN...SHOWED 25KT WINDS JUST OFF OF THE SURFACE AND AS MIXING OCCURS INITIALLY THERE COULD BE A GUST OR TWO AROUND 20 MPH...ESPECIALLY NORTHERN ZONES. DURING THE AFTERNOON... RUC AND THE NAM40 BOTH FORECAST DIMINISHING 925MB WINDS...MAINLY TO 10-20KTS...WITH THE STRONGER WINDS NORTH. THE NAM IS A LITTLE STRONGER THAN THE RUC...AND THE RADAR WIND PROFILES EARLY THIS MORNING LEAN TOWARD THE STRONG NAM WITH ITS HIGHER WINDS VERIFYING. OPTED TO KEEP THE MENTION OF BREEZY CONDITIONS IN NORTHERN ZONES BUT ANTICIPATE THE GRADUALLY FALLING 925MB WINDS TOWARD THE SANDHILLS AND SOUTHERN COASTAL PLAIN SHOULD KEEP SURFACE WINDS FROM GETTING TOO GUSTY THIS AFTERNOON. GRIDDED AND WORDED FORECAST UPDATES ALREADY SENT AND WILL ISSUE ANOTHER UPDATE AROUND THE NOON HOUR TO REMOVE MORNING WORDING AND REFRESH THE GRIDDED AND GRAPHICAL FORECASTS. && .PREV DISCUSSION... /ISSUED 220 AM EDT THU MAR 22 2007/ SYNOPSIS... 1035 MB SURFACE HIGH WAS CENTERED WELL OFFSHORE OF NEW ENGLAND EARLY THURSDAY. THE RIDGE AXIS EXTENDED SW OVER CENTRAL NC INTO NE GA... WITH A RESIDUAL COOL STABLE AIR MASS OVER MUCH OF CENTRAL NC. STRONG WAA WAS OCCURRING JUST WEST OF THE APPALACHIANS. THE SURFACE HIGH WILL MOVE FARTHER EAST TODAY AND THE RIDGE AXIS WILL SHIFT EAST AND SOUTH OF OUR REGION AS WELL. THIS WILL ALLOW WAA TO OVERSPREAD CENTRAL NC TODAY... DISLODGING THE RESIDUAL COOL STABLE AIR MASS BY LATE MORNING. THE FORECAST PROBLEM LATER TODAY THROUGH THE WEEKEND WILL BE HOW WARM THE TEMPERATURES GO AS THE UPPER RIDGE BUILDS TO OUR SW RAISING HEIGHTS... THE MEAN LOW LEVEL FLOW BECOMES WESTERLY... AND THE LOW LEVEL THICKNESSES RISE. SHORT TERM /TODAY THROUGH SUNDAY NIGHT/... THE FIRST PART OF TODAY WILL BE A BIT PROBLEMATIC FOR AMOUNT OF CLOUDS AND EXTENT OF LOW CEILINGS (CIGS). THE MODELS HAVE DONE A POOR JOB INITIALIZING THE CURRENT WEAK COOL AIR DAMMING EVENT. MODELS HAVE BEEN MUCH TOO MOIST IN DEPICTING WIDESPREAD LOW CLOUDS DURING THE PAST 24 HOURS... WHICH DID NOT OCCUR. THE 00Z/22 MARCH RAOBS INDICATED THAT THE BOUNDARY LAYER NEVER BECAME FULLY SATURATED... EVEN OVER THE TYPICAL DAMMING REGION... LIKELY DUE IN PART TO THE LACK OF ANY REAL MEASURABLE RAINFALL. THEREFORE... WE ARE CURRENTLY EXPERIENCING VARIABLE AMOUNTS OF CLOUDINESS WITH MANY AREAS ACTUALLY PARTLY CLOUDY OR MOSTLY CLEAR. WHILE THERE WERE PATCHES OF LOW CLOUDS ESPECIALLY OVER THE PIEDMONT... THERE WERE ONLY MID CLOUDS OBSERVED DOWN EAST AT 06Z/22. THE MOST EXTENSIVE LOW CLOUD DECK IS EXPECTED OVER THE WEST AND NORTH PIEDMONT THROUGH 15Z OR SO. GUIDANCE STILL FORECASTS NEAR SATURATION OF THE BOUNDARY LAYER THROUGH DAYBREAK IN THESE AREAS... WHICH APPEARS LIKELY GIVEN THE RAPIDLY VEERING WINDS IN THE LOWEST 5K FEET SEEN ON THE LATEST VAD... RAOBS... AND FORECAST SOUNDINGS. THIS WILL CONTINUE TO BRING WAA FROM THE S-SW OVER TOP THE COOL STABLE DOME (PIEDMONT AND NORTHERN COASTAL PLAIN PRODUCING BROKEN TO OVERCAST SKIES WITH CIGS BETWEEN 1000 AND 1500 FEET. PARTLY CLOUDY SKIES ARE EXPECTED OVER THE SANDHILLS AND SOUTHERN COASTAL PLAIN... WHERE SOME PATCHY FOG WILL BE POSSIBLE AS THE T/TD SPREAD NARROWS TO LESS THAN 5 DEGREES F BEFORE DAYBREAK. AS THE SURFACE RIDGE ALOFT MOVES OUT THIS MORNING... THE WAA WILL MIX TO THE SURFACE WITH HEATING MID TO LATE MORNING. THIS WILL ALLOW THE WEAK DAMMING EVENT TO SCOUR OUR RAPIDLY. EXPECT THE SKIES TO BECOME MOSTLY SUNNY BY EARLY AFTERNOON. THE WARMER GFS MOS IS SUPPORTED BY THE LOW LEVEL THICKNESS AND AMOUNT OF SUN EXPECTED. WE WILL GO A CATEGORY ABOVE THE GFS MOS AND FORECAST HIGHS WELL INTO THE 70S TODAY. SW WINDS WILL INCREASE TO BETWEEN 10 AND 20 MPH. TONIGHT THROUGH THE WEEKEND... EXPECT A WARM AND DRY PERIOD AS THE UPPER HEIGHTS BUILD... THE H5 RIDGE DEVELOPS TO OUR SW... AND THE FLOW IN THE BOUNDARY LAYER INCREASES FROM THE WEST. A WEAK BACK DOOR FRONT MAY TRY TO EDGE INTO NE NC SATURDAY... BUT A PROGRESSIVE AND RATHER WEAK SURFACE HIGH TO THE NORTH DOES NOT SUPPORT MUCH PUSH THIS FAR SOUTH. ANOTHER BACK DOOR FRONT (STRONGER) SHOULD ARRIVE SUNDAY. THIS WOULD BACK DAYTIME TEMPS MAYBE 10 DEGREES ACROSS THE NE SECTIONS... DEPENDING ON TIMING AND LOCATION. THERE MAY BE SOME INCREASE IN HIGH CLOUDINESS ESPECIALLY NORTHERN AREAS OVER THE WEEKEND... BUT A DRY FORECAST WILL CONTINUE. TEMPS TONIGHT THROUGH THE WEEKEND WILL BE WELL ABOVE NORMAL... (BY 15 TO 20 DEGREES THIS PERIOD). LOWS TONIGHT 52-57... HIGHS FRIDAY 80-85... LOWS FRIDAY NIGHT 55-60... AND HIGHS SATURDAY 80-85. SUNDAY HIGHS OF 74-84 EXPECTED NE TO SW... AND WILL NEED TO BE FINE TUNED LATER. -BADGETT LONG TERM /MONDAY THROUGH WEDNESDAY/... PATTERN FIRST HALF OF NEXT WEEK WILL BE SIMILAR TO THAT OF TODAY... AS HIGH PRESSURE NOSES INTO SOUTH MID ATLC REGION...GRADUALLY SHIFTING OFFSHORE BY MID WEEK. THUS NORTHEAST/EAST FLOW WILL SHIFT AROUND TO SOUTH/SOUTHWEST LATE TUESDAY INTO WEDNESDAY. THIS WILL GENERATE A FAIR AMOUNT OF CLOUDS THROUGH THE PERIOD. WILL CONTINUE PARTLY CLOUDY SKIES BUT WILL INCREASE SKY PERCENTAGES IN GRIDS. CONTINUE ABOVE NORMAL TEMPERATURES... BUT NOT AS WARM AS THIS WEEKEND. -RA AVIATION /05Z-24Z/... MOIST ONSHORE FLOW HAS RESULTED IN CONSIDERABLE STRATOCU OVER WESTERN SECTIONS. THUS MVFR CIGS---1-3KFT AT INT-GSO TAF SITES. EXPECT MVFR CIGS TO GRADUALLY OVERSPREAD REMAINDER OF TAF SITES 08Z-09Z. AFTER 09Z THROUGH 13Z AREAS OF CIGS AT OR BELOW 1KFT VSBYS 3-5 MILES IN FOG. AFTER 14Z EXPECT STRATUS/STRATOCU LAYERS TO MIX OUT BECOMING SCATTERED TO BKN LAYERS 4-6KFT VSBYS UNRESTRICTED. VFR CONDITIONS AT ALL TAF SITES AFTER 16Z. LIGHT AND VARIABLE WINDS THROUGH 13Z THEN BECOMING SOUTHWEST 10 TO 15 MPH. -RA && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...DJF nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 919 AM CDT FRI MAR 23 2007 .UPDATE...AN IMPRESSIVE LOOKING SHORTWAVE ON WATER VAPOR LOOP CURRENTLY OVER MT/SASK WILL BE IN POSITION TO POSSIBLY CAUSE SHOWERS ACROSS THE AREA. SIGNIFICANT WARMING BEFORE ARRIVAL WILL ENSURE THAT ITS PHASE WILL BE LIQUID. 12Z RUC SHOWS IMPRESSIVE LIFT ASSOCIATED WITH THE SHORTWAVE ARRIVING NORTH OF A DVL-GFK-TVF-BDE LINE BETWEEN 00Z-21Z...ENOUGH TO PROBABLY SQUEEZE OUT SOME VERY LIGHT SHOWERS OUT OF THE SCANT MOISTURE. BUT 12Z GGW SOUNDING WAS DRIER THAN 06Z MODELS INDICATED AND RADARS SUGGEST THAT SHOWERS ARE NOT DEVELOPING YET. SO WILL NOT RAISE PROBABILITY AT ALL OR CHANGE TIMING. TEMPERATURE AND WIND ISSUES APPEAR TO BE ON TRACK TOO SO WILL NOT UPDATE THE CURRENT FORECAST ATTM. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ GV nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORMAN OK 852 PM CDT THU MAR 22 2007 .UPDATE... POPS ARE INCREASED TO CATEGORICAL ACROSS MOST OF THE NW HALF OF THE AREA. ALTHOUGH RECENT TRENDS INDICATE THAT MOST IF NOT ALL OF THE SIGNIFICANT RAINFALL WILL BE ACROSS CENTRAL AND N OK... NAM QPF SUGGESTS REDEVELOPMENT LATE TONIGHT ACROSS S OK. THUS LIKELY POPS ARE EXTENDED DOWN INTO SCENTRAL OK AND OUR TX ZONES. MOST AREAS THAT ARE PROJECTED TO GET SIGNIFICANT/HEAVY RAINFALL CAN HANDLE IT SO NO FLOOD WATCHES ARE PLANNED AT THIS TIME. BOW ECHO OVER W OK WILL MOVE INTO OKC AREA BETWEEN 0330Z AND 05Z IF IT MAINTAINS CURRENT COURSE AND SPEED. ALTHOUGH RADAR PRESENTATION HAS BEEN IMPRESSIVE... WE HAVE NOT GATHERED ANY SEVERE WIND REPORTS. HIGHEST GUSTS SO FAR ARE 48MPH AT ERICK MESONET AND 46MPH AT RETROP MESONET. AGREE WITH SWOMCD #321 THAT STORM INTENSITY PROBABLY HAS PREAKED AND SEVERE POTENTIAL WILL DECREASE FROM HERE ON. RERECENT RADAR TRENDS APPEAR TO BEAR THIS OUT... BUT WILL CONTINUE TO MONITOR. 24 && .PREV DISCUSSION... /ISSUED 340 PM CDT THU MAR 22 2007/ DISCUSSION... CONVECTION CONTINUES TO EXPAND FROM NORTHWEST OKLAHOMA INTO THE TEXAS PANHANDLE...WHICH IS IN CLOSEST PROXIMITY TO AN UPPER JET STREAK NEAR THE NEW MEXICO/WEST TEXAS BORDER AND ALSO ON THE PERIPHERY OF A MID/UPPER RIDGE LOCATED OVER OKLAHOMA/NORTH TEXAS. THE LATEST RUC HAS THE BEST MODEL INITIALIZATION AND THUS HAVE FOLLOWED IT CLOSER THROUGH 06Z THAN OTHER SHORT RANGE MODELS. THEREFORE...WE HAVE CONVECTION EXPANDING THROUGH THE EVENING ON THE PERIPHERY OF THE MID/UPPER RIDGE WITH THE MAIN EXCEPTION TO INCREASE THE CHANCES OF THUNDERSTORMS FARTHER SOUTH INTO SOUTHWEST OKLAHOMA AND WESTERN NORTH TEXAS WHERE INSTABILITY IS PEAKING DUE TO CONSISTENT BREAKS IN THE OVERCAST TODAY AND WHERE CONVECTIVE ELEMENTS ON RADAR CONTINUE TO INCREASE. ITS DIFFICULT TO SAY JUST HOW FAR TO CARRY POPS INTO THE UPPER RIDGE OVERNIGHT...BUT WILL PROBABLY BE FAIRLY GENEROUS WITH POPS VALUES AS THERE IS THE POTENTIAL FOR DOWNDRAFTS TO ENHANCE CONVECTIVE DEVELOPMENT...ALONG WITH AN INCREASING LOW LEVEL JET...AND ABUNDANT MID LEVEL MOISTURE. BY FRIDAY...MUCH OF THE AREA MAY BE BETWEEN SYSTEMS AS THE AMPLITUDE OF THE MID/UPPER RIDGE INCREASES. THIS MAY BE PARTICULARLY TRUE ACROSS THE SOUTHEAST CORNER OF THE AREA. DESPITE THE RELATIVE DISTANCE OF THE UPPER LOW...WILL HAVE TO WATCH FOR THE POSSIBILITY OF THE DRYLINE FOCUSING ISOLATED/SCATTERED CONVECTION NEAR THE EASTERN TEXAS PANHANDLE. THE RIDGE IS THEN FORECAST TO BUILD SLOWLY WESTWARD THROUGH SATURDAY WHICH ALSO SHIFTS THE CONCERN FOR HEAVY RAIN AND MAIN FOCUS FOR SEVERE WEATHER INTO THE OKLAHOMA AND TEXAS PANHANDLES. THEN BY SUNDAY/MONDAY...THE LOW BEGINS WEAKENING AND LIFTS NORTHWARD WITH PRECIPITATION CHANCES SPREADING EASTWARD. MOISTURE/INSTABILITY SHOULD REMAIN OVER OR VERY CLOSE THE AREA EVEN AS THE LOW EXITS THE REGION EARLY NEXT WEEK...AS THE LARGE SCALE PATTERN IS ONLY TEMPORARILY SUBSIDENT WITH A VIGOROUS SYSTEM QUICKLY APPROACHING. HAVE FOLLOWED A MODEL CONSENSUS FOR THE MIDDLE OF NEXT WEEK TO SUPPORT LOW POPS AREA-WIDE WITH A LARGE AMPLITUDE UPPER TROUGH SUPPORTING THE POTENTIAL FOR ORGANIZED SEVERE WEATHER SOMEWHERE OVER THE CENTRAL/SOUTHERN PLAINS. HAVE THEN USED PERSISTENCE AND/OR CLIMATOLOGY TO CARRY LOW POPS THROUGH THE OF THE WEEK. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 74 59 76 63 / 30 70 30 20 HOBART OK 73 58 75 61 / 50 80 30 40 WICHITA FALLS TX 76 60 77 62 / 40 70 30 30 GAGE OK 71 53 74 58 / 40 70 40 40 PONCA CITY OK 74 57 73 62 / 60 80 30 20 DURANT OK 73 62 77 64 / 10 40 20 10 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 25/24 ok AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORMAN OK 340 PM CDT THU MAR 22 2007 .DISCUSSION... CONVECTION CONTINUES TO EXPAND FROM NORTHWEST OKLAHOMA INTO THE TEXAS PANHANDLE...WHICH IS IN CLOSEST PROXIMITY TO AN UPPER JET STREAK NEAR THE NEW MEXICO/WEST TEXAS BORDER AND ALSO ON THE PERIPHERY OF A MID/UPPER RIDGE LOCATED OVER OKLAHOMA/NORTH TEXAS. THE LATEST RUC HAS THE BEST MODEL INITIALIZATION AND THUS HAVE FOLLOWED IT CLOSER THROUGH 06Z THAN OTHER SHORT RANGE MODELS. THEREFORE...WE HAVE CONVECTION EXPANDING THROUGH THE EVENING ON THE PERIPHERY OF THE MID/UPPER RIDGE WITH THE MAIN EXCEPTION TO INCREASE THE CHANCES OF THUNDERSTORMS FARTHER SOUTH INTO SOUTHWEST OKLAHOMA AND WESTERN NORTH TEXAS WHERE INSTABILITY IS PEAKING DUE TO CONSISTENT BREAKS IN THE OVERCAST TODAY AND WHERE CONVECTIVE ELEMENTS ON RADAR CONTINUE TO INCREASE. ITS DIFFICULT TO SAY JUST HOW FAR TO CARRY POPS INTO THE UPPER RIDGE OVERNIGHT...BUT WILL PROBABLY BE FAIRLY GENEROUS WITH POPS VALUES AS THERE IS THE POTENTIAL FOR DOWNDRAFTS TO ENHANCE CONVECTIVE DEVELOPMENT...ALONG WITH AN INCREASING LOW LEVEL JET...AND ABUNDANT MID LEVEL MOISTURE. BY FRIDAY...MUCH OF THE AREA MAY BE BETWEEN SYSTEMS AS THE AMPLITUDE OF THE MID/UPPER RIDGE INCREASES. THIS MAY BE PARTICULARLY TRUE ACROSS THE SOUTHEAST CORNER OF THE AREA. DESPITE THE RELATIVE DISTANCE OF THE UPPER LOW...WILL HAVE TO WATCH FOR THE POSSIBILITY OF THE DRYLINE FOCUSING ISOLATED/SCATTERED CONVECTION NEAR THE EASTERN TEXAS PANHANDLE. THE RIDGE IS THEN FORECAST TO BUILD SLOWLY WESTWARD THROUGH SATURDAY WHICH ALSO SHIFTS THE CONCERN FOR HEAVY RAIN AND MAIN FOCUS FOR SEVERE WEATHER INTO THE OKLAHOMA AND TEXAS PANHANDLES. THEN BY SUNDAY/MONDAY...THE LOW BEGINS WEAKENING AND LIFTS NORTHWARD WITH PRECIPITATION CHANCES SPREADING EASTWARD. MOISTURE/INSTABILITY SHOULD REMAIN OVER OR VERY CLOSE THE AREA EVEN AS THE LOW EXITS THE REGION EARLY NEXT WEEK...AS THE LARGE SCALE PATTERN IS ONLY TEMPORARILY SUBSIDENT WITH A VIGOROUS SYSTEM QUICKLY APPROACHING. HAVE FOLLOWED A MODEL CONSENSUS FOR THE MIDDLE OF NEXT WEEK TO SUPPORT LOW POPS AREA-WIDE WITH A LARGE AMPLITUDE UPPER TROUGH SUPPORTING THE POTENTIAL FOR ORGANIZED SEVERE WEATHER SOMEWHERE OVER THE CENTRAL/SOUTHERN PLAINS. HAVE THEN USED PERSISTENCE AND/OR CLIMATOLOGY TO CARRY LOW POPS THROUGH THE OF THE WEEK. .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 59 76 63 77 / 70 30 20 20 HOBART OK 58 75 61 75 / 70 30 40 40 WICHITA FALLS TX 60 77 62 76 / 70 30 30 30 GAGE OK 53 74 58 72 / 40 40 40 60 PONCA CITY OK 57 73 62 77 / 80 30 20 20 DURANT OK 62 77 64 79 / 40 20 10 10 .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. $$ JAMES ok AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 816 PM EDT THU MAR 22 2007 .SHORT TERM /REST OF TONIGHT/... EVENING RADAR IMAGERY SHOWS BULK OF STEADY RAIN ASSOCIATED WITH LL JET HAS NOW PUSHED INTO SOUTHEAST PA...WHILE APPROACHING COLD FRONT IS EVIDENT BY BACK EDGE OF SCT SHWRS NOW MOVING INTO NW MTNS. ENOUGH INSTABILITY REMAINS IN ADVANCE OF FRONT FOR A FEW LIGHTNING STRIKES THIS EVENING...SO WILL ADD SLGHT CHC OF THUNDER TO CENTRAL AND SOUTHERN ZONES. SFC FRONT WILL TAKE UNTIL LATE TONIGHT TO PUSH SOUTH OF MASON DIXON. HOWEVER...WILL CARRY ONLY LOW CHC OF -SHRA AFTER MIDNIGHT...AS LL JET/HIGH PWATS SHIFT EAST OF THE STATE. 18Z MODEL DATA CONTINUES TO SUGGEST CAT POPS ACROSS SOUTHERN PA FRIDAY AS NEXT WAVE RIDES ALONG STALLED FRONTAL BOUNDARY S OF PA. MIDWEST RADARS ALREADY SHOWING ERUPTION OF CONVECTION ASSOCIATED WITH THIS FEATURE...WHICH SHOULD SPREAD RAIN INTO OUR SW ZONES ARND DAWN. && .PREV DISCUSSION... /ISSUED 341 PM EDT THU MAR 22 2007/ SHORT TERM /TONIGHT THROUGH FRIDAY/... REGIONAL RADAR NOW SHOWS CONVECTION INCREASING INTO SWRN PA AND THE LAUREL HIGHLANDS. RUC SHOWS THE CONVECTION MOVING INTO THE AXIS OF BEST INSTABILITY THAT HAS MANAGED TO DEVELOP IN THE SUNSHINE WHICH WE HAVE ENJOYED MUCH OF THE DAY. WITH SOME MODEST CAPE AND STEEPENING MID LEVEL LAPSE RATES...THE CONVECTION IS LIKELY TO CONTINUE OR EVEN INCREASE AS IT MOVES EAST INTO THE CENTRAL MOUNTAINS. SPC FEELS THE SYSTEM WILL OUTRUN THE BEST LOW LEVEL MOISTURE LEADING TO A DIMINISHING OF THE SEVERE THREAT AS IT ENTERS OUR REGION. HOWEVER WITH SUCH STRONG WINDS JUST OFF THE DECK..ANY ORGANIZED CONVECTION THAT MANAGES TO DEVELOP WILL STILL BE CAPABLE OF CAUSING ISOLATED DAMAGING WIND GUSTS. VERY MUDDY PICTURE PAINTED FOR THE REGION OVER THE NEXT FEW DAYS. MODELS AGREE IN SAGGING THE FRONT JUST TO THE SOUTH OF THE PA BORDER BEFORE RIDING A SERIES OF WAVES EAST ALONG IT. FIRST BIG DISCREPANCY ARISES FRIDAY WITH GFS WETTER AND FURTHER NORTH WITH THE LEAD WAVE. NAM TAKES MUCH OF THE RAIN FURTHER SOUTH. 09Z SREF LOOKS MORE LIKE THE NEW GFS. THE 12Z MREF LOOKS SIMILAR TO THE OPERATIONAL GFS. WHAT MAKES EVERYTHING VERY TENUOUS IS THAT THE MODELS MAKE MUCH OF THE RAIN COME FROM MCS`S THAT GENERATE IN THE MID WEST BEFORE HEADING INTO OUR AREA. THIS IS THE STORY RIGHT INTO SUNDAY. RELYING ON THE MODELS GETTING A HANDLE ON CONVECTION MORE THAN A FEW HOURS IN ADVANCE IS ALWAYS A RISKY PROPOSITION. FOR FRIDAY I WENT WITH ENSEMBLE MOS POPS OVER ABOUT THE SOUTHERN HALF OF THE STATE WITH NUMBERS LEANING CLOSER TO THE DRIER NAM MOS POPS OVER THE NORTH. EITHER WAY IT LOOKS LIKE A PRETTY SHARP CUT-OFF TO THE PRECIP ON WHATEVER ENDS UP BEING THE NORTHERN EDGE. LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... COMPLEX SPLIT FLOW REGIME TO CONTEND WITH EARLY IN THE MEDIUM RANGE PERIOD WITH THE MAIN UPPER LEVEL FEATURES BEING A CUT-OFF MID-LVL VORTEX OVER THE DSW AND A FLAT SUBTROPICAL RIDGE CENTERED OVER THE SOUTHEASTERN U.S. AT THE SFC...FOCUS IS ON AN ELONGATED E-W FRONTAL BNDRY STRETCHING FM THE MID MS VLY EWD TO VCNTY MASON-DIXON LINE THEN OFF THE MID-ATLANTIC COAST. MODELS STILL HAVING SOME DIFFICULTY IN HANDLING UPSTREAM ENERGY EJECTING OUT AHEAD OF THE SRN STREAM CUT-OFF...CROSSING THE CENTRAL PLAINS AND REACHING THE NORTHEAST BY SAT-SUN. RECENT TRENDS AND VERIFICATION FROM HPC STRONGLY ARGUE AGAINST THE INCREASINGLY SLOW/DEEP NAM SOLN WITH THE TROF THAT REACHES THE NORTHEAST DURING THE WEEKEND. MODEL DIAGS INDICATE A RECOMMENDATION OF A BLEND OF THE 12Z GLOBAL MODELS AND EPS DATA FOR BOTH TIMING AND QPF. THE ELONGATED FRONTAL BNDRY IS LOCATED IN A ZONE OF UPPER LEVEL CONFLUENCE/LOW-LEVEL BAROCLINICITY BTWN NRN STREAM BELT OF STRONG/PROGRESSIVE WESTERLY FLOW AND PERIPHERY OF SUMMER-LIKE BERMUDA RIDGING OVER THE DEEP SOUTH. EMBEDDED S/W DISTURBANCES EJECTING NEWD AROUND THE SUBTROPICAL DOME AND TRANSLATING EWD ALONG THE AFOREMENTIONED FRONTAL BNDRY WILL MAKE FOR DIFFICULTY IN TIMING/PLACEMENT OF HIGHEST POPS/QPF. HOWEVER...WITH PLENTY OF MOISTURE POOLING NEAR AND ALONG THE Q-STNRY FRONT ON THE NOSE OF A STRONG 850MB LLJ /PWATS +1-2STD ABV NORMAL/ COMBINED WITH ENHANCED/PROLONGED UVVELS COURTESY OF THE RIGHT ENTRANCE REGION OF A 110KT ULJ STREAK WILL CREATE A FAVORABLE ENVIRONMENT FOR NARROW CORRIDOR OF MOD TO HVY PCPN INVOF/TO THE COLD SIDE OF THE LLVL BNDRY. GFS/NAM MODEL QPF ACCUM RUNS SHOW A STRIPE OF 1-2+ INCH RAINFALL EXTENDING FROM THE LWR GRT LKS/MIDDLE OH VLY EWD STRADDLING THE PA/MD BORDER ENDING 00Z SUNDAY. THE MODELS SEEM TO FIZZLE THE FIRST WAVE OVER SRN/SWERN PA LATE FRIDAY INTO SATURDAY AS THE E-W FRONT PIVOTS SLIGHTLY TO A WNW-ESE ORIENTATION. HAVE PLACED HIGHEST POPS NEAR/SOUTH OF THE PA TURNPIKE WHICH AGREES WITH THE SHORT TERM ENS MOS. WAA/THETA-E ADV AND INCREASING ISENTROPIC ASCENT NEAR AND SOUTH OF THE NEARLY STATIONARY FRONT MAY ALLOW FOR SOME SCT OVERRUNNING SHRA TO SPILL INTO THE AREA EARLY SAT BEFORE ANOTHER...MORE POTENT RIDGE-RIDER S/W ARRIVES LATER SATURDAY NIGHT. THIS FEATURE ALMOST LOOKS LIKE AN MCS AS IT BARRELS OVER-TOP THE H5 RIDGE AND DIVES SEWD INTO CENTRAL PA. AS NOTED EARLIER...THE MODELS APPEAR TO BE HAVING SOME ISSUES HANDLING THESE PIECES OF S/W ENERGY AND MAY BE SUFFERING FROM GRID-SCALE CONVECTIVE FEEDBACK AT TIMES. AT ANY RATE...MESOSCALE DETAILS WILL NEED TIME TO BE RESOLVED AND FOR NOW WILL GO WITH STE/ENS MOS POPS WHICH ARE GENERALLY IN THE HIGH CHC CAT /40-50%/ FOR SATURDAY NIGHT AND SUNDAY. THIS IS LOWER THAN THE OPERATIONAL NAM/GFS MOS POPS FOR THIS TIME PD. AS FOR TEMPS...EXACT LOCATION OF FRONTAL BNDRY WILL BE KEY AS IT WILL ACT AS THE DIVIDING LINE BTWN WARM MOIST AIR TO THE SOUTH /60-70S/ AND SLIGHTLY COOLER AIR /40-50S/ TO THE NORTH. HOWEVER OVERALL...GEFS/SREF NORMALIZED ANOMALY FIELDS OF 500 HPA HEIGHTS AND 850MB TEMPS FAVOR AOA CLIMO THRU MUCH OF THE MEDIUM AND LONG RANGE PD WITH POSITIVE ANOMALIES NOTED IN BOTH FIELDS. IN THE LATER PDS...BLENDED HPC/ENS MOS/GRIDDED MOS VALUES WHICH AGAIN RESULTS IN ABOVE NORMAL TEMPS. THE BULK OF THE S/W ENERGY EJECTS NEWD INTO THE UPR MIDWEST SUNDAY INTO MONDAY WITH HIGH-AMPLITUDE RIDGE BUILDING OVER THE EASTERN CONUS. SOME QUESTION HERE AS TO SHARPNESS OF THE H5 RIDGE WITH THE GFS TRENDING STRONGER WITH A S/W TROF DIVING ESEWD OVER THE CANADIAN MARITIMES. A DIFFUSE FRONT ASSOC WITH THE WEAKENING MID AND UPPER LVL ENERGY THAT HAD ORIGINATED OVER THE SW U.S. WILL PASS THRU TUESDAY AND HAVE CONTINUED CHC POPS ACCORDINGLY. STORMY PATTERN CONTINUES ACROSS THE WESTERN AND CENTRAL CONUS AS A VIGOROUS STORM SYSTEM SLAMS INTO THE CENTRAL GRT BASIN AND MOVES INTO THE WESTERN HIGH PLAINS WEDNESDAY. RIDGING DOWNSTREAM WILL KEEP THINGS MAINLY DRY FROM WED-FRI. H5 RIDGE AXIS FCAST TO CROSS THE STATE LATE THUR WITH INC PCPN /-SHRA/ CHCS FOR DY8 AND BEYOND. AVIATION /20Z-18Z/... SHOWERS MOVING INTO WRN PA EARLY THIS AFTERNOON...WILL CONTINUE TO OVERSPREAD THE REGION INTO THE EVENING HOURS. GRADUAL LOWERING OF CEILINGS WILL ACCOMPANY THE INCREASING CHANCE OF SHOWERS. INITIALLY I THINK THAT ONLY AREAS OF MVFR WILL ACCOMPANY THE SHOWERS...BUT AS THE FRONT GETS CLOSER LATER THIS AFTERNOON AND EVENING...A MORE GENERAL LOWERING OF CLOUDS AND VIS TO MVFR WILL BE LIKELY. I HAVE ALL MY TERMINALS IN THE 2000-3000` RANGE WITH 3-6 MILES IN SHOWERS BY AROUND 00Z. ONLY EXCEPTION IS MDT WHERE WEATHER WILL BE SLOWEST TO MOVE IN. CANNOT RULE OUT A GUSTY THUNDERSTORM THROUGH EARLY AFTERNOON AS THE AXIS OF INSTABILITY AND MOISTURE MANAGE TO COINCIDE WITH MAX HEATING WHICH HAS ALLOWED TEMPS IN MOST LOCATIONS TO EDGE UP INTO THE 60S. FAR EASTERN LOCATIONS WHERE THE COOL AIR DAMMING HAS BEEN STUBBORN...THEY ARE A BIT COOLER BUT WILL LIKELY JUMP UP INTO THE LOWER 60S AT LEAST ONCE THE WIND MIXES THEM OUT. WINDS ALOFT ARE HOWLING 45-55KT SO ISOLATED STRONG GUSTS WITH THE THUNDERSTORMS SEEMS LIKELY. AFTER THE FRONT SAGS SOUTH BY AROUND MIDNIGHT...THE WEATHER QUESTIONS CLOUDY...EXCUSE THE PUN. DIFFERING GUIDANCE SHOWS THE FRONT BECOMING Q-STATIONARY AND SETTING A SERIES OF WAVES TO MOVE EAST ALONG IT. GFS IS MUCH WETTER AND COVERS ABOUT THE SOUTHERN 3/4 OF MY FCST AREA WITH A SOAKING RAIN TOMORROW. THE NAM IS FURTHER SOUTH WITH ITS PRECIP SHIELD. THIS LEADS TO THE USUAL UNCERTAINTY AND HAS IMPLICATIONS AS TO WHICH TERMINALS WILL IMPROVE AND WHEN. AS IT STANDS RIGHT NOW...THE MOST LIKELY AIRPORTS TO MAINTAIN MVFR OR LOWER CONDITIONS WILL BE OVER THE SOUTHERN HALF OR SO OF THE FCST AREA. AOO-UNV WILL BE CLOSER TO THE LINE WHERE IT COULD EITHER BE SCATTERED AND VFR OR RAINING AND MVFR OR WORSE. STILL TOO EARLY TO BE SPECIFIC. HYDROLOGY... THE COMBINATION OF RUNOFF FROM RAINFALL AND SNOW MELT WILL PRODUCE MODERATE TO SIGNIFICANT RISES ALONG THE NORTH BRANCH AND MAIN STEM OF THE SUSQUEHANNA RIVER AND ITS TRIBUTARIES FOR THE NEXT COUPLE OF DAYS. NEAR BANKFULL CONDITIONS WILL BE APPROACHED IN SOME AREAS WITH MINOR FLOODING POSSIBLE. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...FITZGERALD pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 341 PM EDT THU MAR 22 2007 .SHORT TERM /TONIGHT THROUGH FRIDAY/... REGIONAL RADAR NOW SHOWS CONVECTION INCREASING INTO SWRN PA AND THE LAUREL HIGHLANDS. RUC SHOWS THE CONVECTION MOVING INTO THE AXIS OF BEST INSTABILITY THAT HAS MANAGED TO DEVELOP IN THE SUNSHINE WHICH WE HAVE ENJOYED MUCH OF THE DAY. WITH SOME MODEST CAPE AND STEEPENING MID LEVEL LAPSE RATES...THE CONVECTION IS LIKELY TO CONTINUE OR EVEN INCREASE AS IT MOVES EAST INTO THE CENTRAL MOUNTAINS. SPC FEELS THE SYSTEM WILL OUTRUN THE BEST LOW LEVEL MOISTURE LEADING TO A DIMINISHING OF THE SEVERE THREAT AS IT ENTERS OUR REGION. HOWEVER WITH SUCH STRONG WINDS JUST OFF THE DECK..ANY ORGANIZED CONVECTION THAT MANAGES TO DEVELOP WILL STILL BE CAPABLE OF CAUSING ISOLATED DAMAGING WIND GUSTS. VERY MUDDY PICTURE PAINTED FOR THE REGION OVER THE NEXT FEW DAYS. MODELS AGREE IN SAGGING THE FRONT JUST TO THE SOUTH OF THE PA BORDER BEFORE RIDING A SERIES OF WAVES EAST ALONG IT. FIRST BIG DISCREPANCY ARISES FRIDAY WITH GFS WETTER AND FURTHER NORTH WITH THE LEAD WAVE. NAM TAKES MUCH OF THE RAIN FURTHER SOUTH. 09Z SREF LOOKS MORE LIKE THE NEW GFS. THE 12Z MREF LOOKS SIMILAR TO THE OPERATIONAL GFS. WHAT MAKES EVERYTHING VERY TENUOUS IS THAT THE MODELS MAKE MUCH OF THE RAIN COME FROM MCS`S THAT GENERATE IN THE MID WEST BEFORE HEADING INTO OUR AREA. THIS IS THE STORY RIGHT INTO SUNDAY. RELYING ON THE MODELS GETTING A HANDLE ON CONVECTION MORE THAN A FEW HOURS IN ADVANCE IS ALWAYS A RISKY PROPOSITION. FOR FRIDAY I WENT WITH ENSEMBLE MOS POPS OVER ABOUT THE SOUTHERN HALF OF THE STATE WITH NUMBERS LEANING CLOSER TO THE DRIER NAM MOS POPS OVER THE NORTH. EITHER WAY IT LOOKS LIKE A PRETTY SHARP CUT-OFF TO THE PRECIP ON WHATEVER ENDS UP BEING THE NORTHERN EDGE. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... COMPLEX SPLIT FLOW REGIME TO CONTEND WITH EARLY IN THE MEDIUM RANGE PERIOD WITH THE MAIN UPPER LEVEL FEATURES BEING A CUT-OFF MID-LVL VORTEX OVER THE DSW AND A FLAT SUBTROPICAL RIDGE CENTERED OVER THE SOUTHEASTERN U.S. AT THE SFC...FOCUS IS ON AN ELONGATED E-W FRONTAL BNDRY STRETCHING FM THE MID MS VLY EWD TO VCNTY MASON-DIXON LINE THEN OFF THE MID-ATLANTIC COAST. MODELS STILL HAVING SOME DIFFICULTY IN HANDLING UPSTREAM ENERGY EJECTING OUT AHEAD OF THE SRN STREAM CUT-OFF...CROSSING THE CENTRAL PLAINS AND REACHING THE NORTHEAST BY SAT-SUN. RECENT TRENDS AND VERIFICATION FROM HPC STRONGLY ARGUE AGAINST THE INCREASINGLY SLOW/DEEP NAM SOLN WITH THE TROF THAT REACHES THE NORTHEAST DURING THE WEEKEND. MODEL DIAGS INDICATE A RECOMMENDATION OF A BLEND OF THE 12Z GLOBAL MODELS AND EPS DATA FOR BOTH TIMING AND QPF. THE ELONGATED FRONTAL BNDRY IS LOCATED IN A ZONE OF UPPER LEVEL CONFLUENCE/LOW-LEVEL BAROCLINICITY BTWN NRN STREAM BELT OF STRONG/PROGRESSIVE WESTERLY FLOW AND PERIPHERY OF SUMMER-LIKE BERMUDA RIDGING OVER THE DEEP SOUTH. EMBEDDED S/W DISTURBANCES EJECTING NEWD AROUND THE SUBTROPICAL DOME AND TRANSLATING EWD ALONG THE AFOREMENTIONED FRONTAL BNDRY WILL MAKE FOR DIFFICULTY IN TIMING/PLACEMENT OF HIGHEST POPS/QPF. HOWEVER...WITH PLENTY OF MOISTURE POOLING NEAR AND ALONG THE Q-STNRY FRONT ON THE NOSE OF A STRONG 850MB LLJ /PWATS +1-2STD ABV NORMAL/ COMBINED WITH ENHANCED/PROLONGED UVVELS COURTESY OF THE RIGHT ENTRANCE REGION OF A 110KT ULJ STREAK WILL CREATE A FAVORABLE ENVIRONMENT FOR NARROW CORRIDOR OF MOD TO HVY PCPN INVOF/TO THE COLD SIDE OF THE LLVL BNDRY. GFS/NAM MODEL QPF ACCUM RUNS SHOW A STRIPE OF 1-2+ INCH RAINFALL EXTENDING FROM THE LWR GRT LKS/MIDDLE OH VLY EWD STRADDLING THE PA/MD BORDER ENDING 00Z SUNDAY. THE MODELS SEEM TO FIZZLE THE FIRST WAVE OVER SRN/SWERN PA LATE FRIDAY INTO SATURDAY AS THE E-W FRONT PIVOTS SLIGHTLY TO A WNW-ESE ORIENTATION. HAVE PLACED HIGHEST POPS NEAR/SOUTH OF THE PA TURNPIKE WHICH AGREES WITH THE SHORT TERM ENS MOS. WAA/THETA-E ADV AND INCREASING ISENTROPIC ASCENT NEAR AND SOUTH OF THE NEARLY STATIONARY FRONT MAY ALLOW FOR SOME SCT OVERRUNNING SHRA TO SPILL INTO THE AREA EARLY SAT BEFORE ANOTHER...MORE POTENT RIDGE-RIDER S/W ARRIVES LATER SATURDAY NIGHT. THIS FEATURE ALMOST LOOKS LIKE AN MCS AS IT BARRELS OVER-TOP THE H5 RIDGE AND DIVES SEWD INTO CENTRAL PA. AS NOTED EARLIER...THE MODELS APPEAR TO BE HAVING SOME ISSUES HANDLING THESE PIECES OF S/W ENERGY AND MAY BE SUFFERING FROM GRID-SCALE CONVECTIVE FEEDBACK AT TIMES. AT ANY RATE...MESOSCALE DETAILS WILL NEED TIME TO BE RESOLVED AND FOR NOW WILL GO WITH STE/ENS MOS POPS WHICH ARE GENERALLY IN THE HIGH CHC CAT /40-50%/ FOR SATURDAY NIGHT AND SUNDAY. THIS IS LOWER THAN THE OPERATIONAL NAM/GFS MOS POPS FOR THIS TIME PD. AS FOR TEMPS...EXACT LOCATION OF FRONTAL BNDRY WILL BE KEY AS IT WILL ACT AS THE DIVIDING LINE BTWN WARM MOIST AIR TO THE SOUTH /60-70S/ AND SLIGHTLY COOLER AIR /40-50S/ TO THE NORTH. HOWEVER OVERALL...GEFS/SREF NORMALIZED ANOMALY FIELDS OF 500 HPA HEIGHTS AND 850MB TEMPS FAVOR AOA CLIMO THRU MUCH OF THE MEDIUM AND LONG RANGE PD WITH POSITIVE ANOMALIES NOTED IN BOTH FIELDS. IN THE LATER PDS...BLENDED HPC/ENS MOS/GRIDDED MOS VALUES WHICH AGAIN RESULTS IN ABOVE NORMAL TEMPS. THE BULK OF THE S/W ENERGY EJECTS NEWD INTO THE UPR MIDWEST SUNDAY INTO MONDAY WITH HIGH-AMPLITUDE RIDGE BUILDING OVER THE EASTERN CONUS. SOME QUESTION HERE AS TO SHARPNESS OF THE H5 RIDGE WITH THE GFS TRENDING STRONGER WITH A S/W TROF DIVING ESEWD OVER THE CANADIAN MARITIMES. A DIFFUSE FRONT ASSOC WITH THE WEAKENING MID AND UPPER LVL ENERGY THAT HAD ORIGINATED OVER THE SW U.S. WILL PASS THRU TUESDAY AND HAVE CONTINUED CHC POPS ACCORDINGLY. STORMY PATTERN CONTINUES ACROSS THE WESTERN AND CENTRAL CONUS AS A VIGOROUS STORM SYSTEM SLAMS INTO THE CENTRAL GRT BASIN AND MOVES INTO THE WESTERN HIGH PLAINS WEDNESDAY. RIDGING DOWNSTREAM WILL KEEP THINGS MAINLY DRY FROM WED-FRI. H5 RIDGE AXIS FCAST TO CROSS THE STATE LATE THUR WITH INC PCPN /-SHRA/ CHCS FOR DY8 AND BEYOND. && .AVIATION /20Z-18Z/... SHOWERS MOVING INTO WRN PA EARLY THIS AFTERNOON...WILL CONTINUE TO OVERSPREAD THE REGION INTO THE EVENING HOURS. GRADUAL LOWERING OF CEILINGS WILL ACCOMPANY THE INCREASING CHANCE OF SHOWERS. INITIALLY I THINK THAT ONLY AREAS OF MVFR WILL ACCOMPANY THE SHOWERS...BUT AS THE FRONT GETS CLOSER LATER THIS AFTERNOON AND EVENING...A MORE GENERAL LOWERING OF CLOUDS AND VIS TO MVFR WILL BE LIKELY. I HAVE ALL MY TERMINALS IN THE 2000-3000` RANGE WITH 3-6 MILES IN SHOWERS BY AROUND 00Z. ONLY EXCEPTION IS MDT WHERE WEATHER WILL BE SLOWEST TO MOVE IN. CANNOT RULE OUT A GUSTY THUNDERSTORM THROUGH EARLY AFTERNOON AS THE AXIS OF INSTABILITY AND MOISTURE MANAGE TO COINCIDE WITH MAX HEATING WHICH HAS ALLOWED TEMPS IN MOST LOCATIONS TO EDGE UP INTO THE 60S. FAR EASTERN LOCATIONS WHERE THE COOL AIR DAMMING HAS BEEN STUBBORN...THEY ARE A BIT COOLER BUT WILL LIKELY JUMP UP INTO THE LOWER 60S AT LEAST ONCE THE WIND MIXES THEM OUT. WINDS ALOFT ARE HOWLING 45-55KT SO ISOLATED STRONG GUSTS WITH THE THUNDERSTORMS SEEMS LIKELY. AFTER THE FRONT SAGS SOUTH BY AROUND MIDNIGHT...THE WEATHER QUESTIONS CLOUDY...EXCUSE THE PUN. DIFFERING GUIDANCE SHOWS THE FRONT BECOMING Q-STATIONARY AND SETTING A SERIES OF WAVES TO MOVE EAST ALONG IT. GFS IS MUCH WETTER AND COVERS ABOUT THE SOUTHERN 3/4 OF MY FCST AREA WITH A SOAKING RAIN TOMORROW. THE NAM IS FURTHER SOUTH WITH ITS PRECIP SHIELD. THIS LEADS TO THE USUAL UNCERTAINTY AND HAS IMPLICATIONS AS TO WHICH TERMINALS WILL IMPROVE AND WHEN. AS IT STANDS RIGHT NOW...THE MOST LIKELY AIRPORTS TO MAINTAIN MVFR OR LOWER CONDITIONS WILL BE OVER THE SOUTHERN HALF OR SO OF THE FCST AREA. AOO-UNV WILL BE CLOSER TO THE LINE WHERE IT COULD EITHER BE SCATTERED AND VFR OR RAINING AND MVFR OR WORSE. STILL TOO EARLY TO BE SPECIFIC. && .HYDROLOGY... THE COMBINATION OF RUNOFF FROM RAINFALL AND SNOW MELT WILL PRODUCE MODERATE TO SIGNIFICANT RISES ALONG THE NORTH BRANCH AND MAIN STEM OF THE SUSQUEHANNA RIVER AND ITS TRIBUTARIES FOR THE NEXT COUPLE OF DAYS. NEAR BANKFULL CONDITIONS WILL BE APPROACHED IN SOME AREAS WITH MINOR FLOODING POSSIBLE. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...LACORTE LONG TERM...STEINBUGL AVIATION...LACORTE HYDROLOGY...STEINBUGL pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 1101 AM EDT THU MAR 22 2007 .SHORT TERM /REST OF TODAY/... REGIONAL RADARS SHOW A SLOWLY DIMINISHING SQUALL LINE FROM SRN LAKE HURON DOWN INTO SWRN OHIO. RUC AND MESO ANALS INDICATE THAT THE CONVECTION IS ASSOC WITH A WEDGE OF LOW LEVEL CONVERGENCE AND INSTABILITY THAT HAS DEVELOPED AHEAD OF THE FRONT...WHICH AT 14Z WAS MOVING THRU MICH AND EXTENDED TO JUST EAST OF CHICAGO. MODELS SHOW THE FRONT ENTERING THE STATE BY EARLY TO MID AFTERNOON...THEN SLOWLY SAGGING SOUTH INTO THE EVENING HOURS. THE BEST LOW LEVEL FOCUSING SHUD BE JUST ENTERING CENTRAL PA BETWEEN 18-21Z. RUC STILL SHOWS SOME MEASURE OF INSTABILITY WITH LI`S JUST BELOW ZERO...SOME MODEST CAPE VALUES AND IMPRESSIVE SPEED SHEAR THRU THE LOWER 10K FEET OR SO OF THE ATMOS. SPC FEELS THE SYSTEM WILL OUTRUN THE BEST LOW LEVEL MOISTURE LEADING TO A DIMINISHING OF THE SEVERE THREAT AS IT ENTERS OUR REGION. HOWEVER WITH SUCH STRONG WINDS JUST OFF THE DECK..ANY ORGANIZED CONVECTION THAT MANAGES TO DEVELOP WILL STILL BE CAPABLE OF CAUSING ISOLATED DAMAGING WIND GUSTS. LATE MORNING UPDATE WILL BE ISSUED SOON...WITH SOME FINE TUNING OF THE SHOWER/THUNDERSTORM POTENTIAL AND TIMING. LA CORTE && .PREV DISCUSSION... /ISSUED 345 AM EDT THU MAR 22 2007/ SYNOPSIS... MILDER AIR WILL BE IN PLACE ACROSS THE REGION FOR THE NEXT SEVERAL DAYS. A WEAK COLD FRONT WILL BRING ONE ROUND OF SHOWERS AND POSSIBLE THUNDERSTORMS TO CENTRAL PENN THIS AFTERNOON AND TONIGHT...BEFORE STALLING OUT FROM NORTHERN VIRGINIA TO SOUTHWESTERN PENN FRIDAY INTO SATURDAY. ANOTHER DISTURBANCE ALOFT WILL MOVE OUT OF THE OHIO VALLEY AND RIDE JUST TO NORTH OF OF THIS BOUNDARY FRIDAY NIGHT...BRINGING WITH IT ANOTHER ONE QUARTER TO ONE HALF INCH OF RAIN. SHORT TERM /TODAY THROUGH FRIDAY NIGHT/... ALL OF CENTRAL PENN IS NESTLED IN THE WARM SECTOR EARLY THIS MORNING WITH A 5 TO 10 KT SOUTH TO SE FLOW AT MOST OB SITES. TEMPS IN THE MID TO UPPER 30S ARE 5 TO 10 DEG F ABOVE NORMAL FOR AN EARLY SPRING MORNING. DEPARTURES OF 10 TO 15F ABOVE NORMAL WILL OCCUR WITH THIS AFTERNOON/S MAX TEMPS /IN THE MID TO U50S NORTH AND LOWER TO MID 60S ACROSS THE SOUTH/ AHEAD OF A COLD FRONT...CURRENTLY LOCATED FROM LAKE SUPERIOR...SWD THROUGH EASTERN IOWA. POCKETS OF SFC BASED LIFTED INDICES IN THE -1 TO -3 RANGE WILL DEVELOP LATER TODAY AND THIS EVENING JUST AHEAD OF THE FRONT WITHIN A FAIRLY NARROW BELT OF ABOVE NORMAL /PLUS 2-3 STANDARD DEVIATIONS/ PRECIP WATER OF AROUND ONE INCH AS DEPICTED BY THE 21Z SREF. NEAR TO SLIGHTLY BELOW NORMAL PWATS WILL SAG INTO MOST OF PENN FRIDAY MORNING AS THE FRONT PUSHES TEMPORARILY SWD INTO VIRGINIA AND THE CENTRAL OHIO RIVER VALLEY. ABOVE NORMAL PWATS DEVELOP AGAIN LATE FRIDAY AND FRI NIGHT...WITH VALUES EXCEEDING ONE INCH NEAR THE MASON...DIXON LINE. THE MUCH FASTER GFS AND NAM /WHICH IS IN BETTER AGREEMENT WITH OTHER OPERATIONAL MODELS AND THE SREF MEAN IN THE LOCATION OF UPPER MID AND UPPER LEVEL FORCING/QPF/ ARE NEARLY 180 DEG OUT OF PHASE W/RESPECT TO THE TIMING OF SEVERAL ROUNDS OF SHOWERS THROUGH SAT NIGHT. PAINTED CLOUD...POP/WEATHER AND WIND GRIDS BASED ON THE SREF. ALSO FOLLOWED SHORT TERM ENSEMBLE MOS VALUES QUITE CLOSELY FOR MAX AND MIN TEMPS THROUGH SATURDAY. PLEASE REFER TO THE HYDRO SECTION BELOW FOR SPECIFICS ON THE TIMING AND AMOUNT OF QPF. COMBINED QPF AND SNOWMELT OVER THE UPCOMING 48 HOUR STRETCH WILL RANGE AS HIGH AS 1.0 TO 1.5 INCHES. RAINFALL FOR FRIDAY NIGHT COULD BE UNDERESTIMATED SHOULD THE LOCATION AND STRENGTH OF THE NAM`S LEFT EXIT REGION OF A 115 KT UPPER BETTER VERIFY. LONG TERM /SATURDAY THROUGH WEDNESDAY/... BOTH THE GFS AND 12 KM NAM INDICATE A DRIER AND MILD SECOND HALF OF THE UPCOMING WEEKEND AS THE UPPER LEVEL FLOW VEERS TO A MORE NWRLY DIRECTION AND A BUBBLE OF HIGH PRESSURE AT THE SFC BUILDS OVER THE STATE. IT STILL APPEARS THAT CLOUDS WILL INCREASE MONDAY NIGHT/TUESDAY WITH SHOWERS SPREADING ACROSS CENTRAL PENN LATER TUESDAY/TUES NIGHT IN ASSOCIATION WITH THE NEXT...WEAKENING COLD FRONT. TEMPS MAY BRIEFLY DIP TO A FEW DEG BELOW NORMAL TUESDAY/TUESDAY NIGHT JUST IN THE WAKE OF THE FRONT...BEFORE REBOUNDING AGAIN DURING THE MIDDLE/LATTER PART OF NEXT WEEK. AVIATION /08Z-06Z/... CLEAR SKIES WILL CONTINUE THROUGH 10-12Z BUT DID MENTION A PERIOD OF MVFR AS WARM ADVECTION ROLLS OVER A DWINDLING SNOW COVER. CEILINGS WILL LOWER THROUGH 18Z AS PRECIPITATION DEVELOPS AHEAD OF A FRONTAL BOUNDARY. LEFT OUT MENTION OF THUNDER FOR SPECIFIC AIRFIELDS AS THE COVERAGE MAY BE RIGHT ON THE CUSP OF VCTS. WILL CONSIDER ADDING VCTS IN THE 12Z PACKAGE FOR THE WESTERN AIRFIELDS OF KJST AND KBFD. WINDS WILL INCREASE FROM 210-230 AFTER 14Z AHEAD OF THE FRONT...GUSTING TO 15-20KTS AT ALL LOCATIONS. THE SURFACE FRONT WILL CROSS THE FORECAST AREA AROUND 00Z AND WINDS WILL SHIFT TO THE WEST AND DIMINISH TO LESS THAN 10 KTS. HYDROLOGY... COLD FRONT MOVING SOUTHEAST LATER TODAY AND TONIGHT WILL BRING BETWEEN 2 TENTHS AND 4 TENTHS OF AN INCH OF BASIN AVERAGE RAIN TO THE WRN MTNS OF PENN...WITH SLIGHTLY LESSER AMOUNTS TONIGHT/EARLY FRIDAY ACROSS THE CENTRAL ZONES AND SUSQUEHANNA RIVER VALLEY. MELTING OF THE ONE HALF...TO ONE INCH OF WATER EQUIVALENT IN THE RIPE SNOWPACK WILL LIKELY PLAY A BIGGER FACTOR IN RUNOFF INTO STREAMS AND RIVERS OVER THE NEXT 24 TO 48 HOURS. ANOTHER ROUND OF RAIN IS EXPECTED FOR LATER FRIDAY AND FRIDAY NIGHT WITH BASIN AVERAGE AMOUNTS SLIGHTLY HIGHER...BETWEEN 3 AND 5 TENTHS OF AN INCH. LOWER WATER EQUIVALENT IN THE SNOWPACK ACROSS OUR SW MTNS /RELATIVE TO THE NCENT MTNS/ WILL COMBINE WITH THE SOMEWHAT HIGHER 48 HR RAINFALL FROM KJST TO KBFD...YIELDING SIMILAR TOTAL RUNOFF INTO AREAS STREAMS AND RIVERS. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 1015 PM CDT FRI MAR 23 2007 .UPDATE... UPDATED ZONES FOR TORNADO WATCH #73 FOR STERLING COUNTY. && .PREV DISCUSSION... /ISSUED 903 PM CDT FRI MAR 23 2007/ UPDATE... WILL NOT MAKE ANY CHANGES TO THE FORECAST. HAD ONE SUPERCELL MOVE ACROSS EXTREME NORTHWEST CROCKETT COUNTY. THIS STORM IS NOW OVER UPTON COUNTY. THE CHC POPS LOOK GOOD FOR TONIGHT...AS INCREASING LOW LEVEL JET MAY AID IN THE DEVELOPMENT OF SCATTERED TSTMS...MAINLY AFTER MIDNIGHT. 21 PREV DISCUSSION... /ISSUED 620 PM CDT FRI MAR 23 2007/ AVIATION...NOT MUCH CHANGE IN THE AVIATION FORECAST THAN WHAT WE HAVE SEEN THE PAST SEVERAL DAYS. WILL SEE MVFR CIGS INVADE ONCE AGAIN AFTER 06Z. GUSTY WINDS WILL CONTINUE THROUGH MUCH OF THE NIGHT WITH THE EXCEPTION OF JCT AND BBD WHERE GUSTS SHOULD SUBSIDE AFTER SUNSET. WILL ONCE AGAIN SEE LIGHT RAIN AND DRIZZLE AREAS AGAIN IN THE MORNING...BUT TIMING AND RESTRICTIONS TO VISBYS NOT CERTAIN AND WILL NOT INCLUDE AT THIS TIME. THUNDERSTORMS WILL BE INCREASING IN COVERAGE OVER THE NEXT 24 HOURS...BUT AGAIN TIMING AND LOCATIONS STILL NOT CERTAIN ENOUGH FOR A MENTION AT THIS TIME. MAY HAVE TO INCLUDE PROB OR TEMPO GROUPS IN LATTER FORECAST ONCE THESE BECOME BETTER DETERMINED. BRAZZELL PREV DISCUSSION... /ISSUED 300 PM CDT FRI MAR 23 2007/ SHORT TERM... UPPER CLOSED LOW IS MOVING FROM THE NORTHERN BAJA INTO NORTHERN MEXICO THIS AFTERNOON. LOW LEVEL MOISTURE IS BACKED UP ALL THE WAY TO THE NEW MEXICO MOUNTAINS WITH DEW POINTS IN THE 50S INTO SOUTHEASTERN NEW MEXICO. SOUTHWEST TEXAS AND SOUTHEASTERN NEW MEXICO ARE RELATIVELY CLOUDLESS THIS AFTERNOON IN ADVANCE OF THE UPPER LOW ALLOWING FOR GOOD AFTERNOON HEATING...A FEW THUNDERSTORMS HAVE ALREADY BEGUN FORMING OFF THE HIGHER TERRAIN IN WEST TEXAS AND SOUTHERN NEW MEXICO. THE MAIN UPPER LOW WILL BE ENTERING SOUTHWEST NEW MEXICO THIS EVENING ON A TRACK THAT PUTS IT INTO SOUTHEASTERN COLORADO BY TOMORROW MORNING. AS INDICTED ON THE LATEST RUC...NEAR 50 KNOT LLJ WILL CRANK UP OVER THE PERMIAN BASIN THIS EVENING AND GIVEN GOOD INHERENT DYNAMICS ASSOCIATED WITH THE APPROACHING UPPER LEVEL SYSTEM...SHOULD SEE ADDITIONAL CONVECTIVE ACTIVITY HEATING UP THIS EVENING AND MOVE TO THE NORTHEAST. HAVE INCLUDED A CHANCE OF SEVERE IN OUR WESTERN COUNTIES TONIGHT GIVEN THEIR CLOSE PROXIMITY TO THE ANTICIPATED STORMS. UPPER LOW WILL BEGIN BIFURCATING TOMORROW WITH THE SECOND CLOSED LOW FORMING OVER ARIZONA AND MOVING SOUTHEAST INTO NORTHERN MEXICO SUNDAY NIGHT. MAIN TROUGH AXIS WILL PROVIDE A BETTER CHANCE OF RAINFALL FOR OUR FORECAST AREA BEGINNING SUNDAY AS IT MOVES EAST. TROUGH AXIS WILL PASS THROUGH WEST CENTRAL TEXAS ON MONDAY WITH THE BEST CHANCE OF RAINFALL SUNDAY THROUGH MONDAY. LONG TERM... UPPER TROUGH AXIS FINALLY MOVES EAST OF THE AREA LATE MONDAY BRINGING THIS ROUND OF PRECIPITATION TO A CLOSE. WE WILL HAVE A BRIEF RESPITE AS UPPER RIDGING BUILDS IN BEHIND THE DEPARTING TROUGH. ANOTHER UPPER LEVEL SYSTEM WILL MOVE FROM THE CENTRAL CALIFORNIA COAST INTO THE SOUTHERN PLAINS PUSHING A PACIFIC FRONT INTO THE AREA LATE WEDNESDAY. HAVE INCLUDED A CHANCE OF RAINFALL WEDNESDAY INTO FRIDAY ASSOCIATED WITH THIS SYSTEM. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 72 62 75 59 / 30 50 30 30 SAN ANGELO 75 59 72 57 / 30 50 30 30 JUNCTION 75 63 72 61 / 40 40 20 40 && .SJT WATCHES/WARNINGS/ADVISORIES... ...TORNADO WATCH #73 IN EFFECT UNTIL 500 AM FOR STERLING COUNTY... && $$ tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 903 PM CDT FRI MAR 23 2007 .UPDATE... WILL NOT MAKE ANY CHANGES TO THE FORECAST. HAD ONE SUPERCELL MOVE ACROSS EXTREME NORTHWEST CROCKETT COUNTY. THIS STORM IS NOW OVER UPTON COUNTY. THE CHC POPS LOOK GOOD FOR TONIGHT...AS INCREASING LOW LEVEL JET MAY AID IN THE DEVELOPMENT OF SCATTERED TSTMS...MAINLY AFTER MIDNIGHT. 21 && .PREV DISCUSSION... /ISSUED 620 PM CDT FRI MAR 23 2007/ AVIATION...NOT MUCH CHANGE IN THE AVIATION FORECAST THAN WHAT WE HAVE SEEN THE PAST SEVERAL DAYS. WILL SEE MVFR CIGS INVADE ONCE AGAIN AFTER 06Z. GUSTY WINDS WILL CONTINUE THROUGH MUCH OF THE NIGHT WITH THE EXCEPTION OF JCT AND BBD WHERE GUSTS SHOULD SUBSIDE AFTER SUNSET. WILL ONCE AGAIN SEE LIGHT RAIN AND DRIZZLE AREAS AGAIN IN THE MORNING...BUT TIMING AND RESTRICTIONS TO VISBYS NOT CERTAIN AND WILL NOT INCLUDE AT THIS TIME. THUNDERSTORMS WILL BE INCREASING IN COVERAGE OVER THE NEXT 24 HOURS...BUT AGAIN TIMING AND LOCATIONS STILL NOT CERTAIN ENOUGH FOR A MENTION AT THIS TIME. MAY HAVE TO INCLUDE PROB OR TEMPO GROUPS IN LATTER FORECAST ONCE THESE BECOME BETTER DETERMINED. BRAZZELL PREV DISCUSSION... /ISSUED 300 PM CDT FRI MAR 23 2007/ SHORT TERM... UPPER CLOSED LOW IS MOVING FROM THE NORTHERN BAJA INTO NORTHERN MEXICO THIS AFTERNOON. LOW LEVEL MOISTURE IS BACKED UP ALL THE WAY TO THE NEW MEXICO MOUNTAINS WITH DEW POINTS IN THE 50S INTO SOUTHEASTERN NEW MEXICO. SOUTHWEST TEXAS AND SOUTHEASTERN NEW MEXICO ARE RELATIVELY CLOUDLESS THIS AFTERNOON IN ADVANCE OF THE UPPER LOW ALLOWING FOR GOOD AFTERNOON HEATING...A FEW THUNDERSTORMS HAVE ALREADY BEGUN FORMING OFF THE HIGHER TERRAIN IN WEST TEXAS AND SOUTHERN NEW MEXICO. THE MAIN UPPER LOW WILL BE ENTERING SOUTHWEST NEW MEXICO THIS EVENING ON A TRACK THAT PUTS IT INTO SOUTHEASTERN COLORADO BY TOMORROW MORNING. AS INDICTED ON THE LATEST RUC...NEAR 50 KNOT LLJ WILL CRANK UP OVER THE PERMIAN BASIN THIS EVENING AND GIVEN GOOD INHERENT DYNAMICS ASSOCIATED WITH THE APPROACHING UPPER LEVEL SYSTEM...SHOULD SEE ADDITIONAL CONVECTIVE ACTIVITY HEATING UP THIS EVENING AND MOVE TO THE NORTHEAST. HAVE INCLUDED A CHANCE OF SEVERE IN OUR WESTERN COUNTIES TONIGHT GIVEN THEIR CLOSE PROXIMITY TO THE ANTICIPATED STORMS. UPPER LOW WILL BEGIN BIFURCATING TOMORROW WITH THE SECOND CLOSED LOW FORMING OVER ARIZONA AND MOVING SOUTHEAST INTO NORTHERN MEXICO SUNDAY NIGHT. MAIN TROUGH AXIS WILL PROVIDE A BETTER CHANCE OF RAINFALL FOR OUR FORECAST AREA BEGINNING SUNDAY AS IT MOVES EAST. TROUGH AXIS WILL PASS THROUGH WEST CENTRAL TEXAS ON MONDAY WITH THE BEST CHANCE OF RAINFALL SUNDAY THROUGH MONDAY. LONG TERM... UPPER TROUGH AXIS FINALLY MOVES EAST OF THE AREA LATE MONDAY BRINGING THIS ROUND OF PRECIPITATION TO A CLOSE. WE WILL HAVE A BRIEF RESPITE AS UPPER RIDGING BUILDS IN BEHIND THE DEPARTING TROUGH. ANOTHER UPPER LEVEL SYSTEM WILL MOVE FROM THE CENTRAL CALIFORNIA COAST INTO THE SOUTHERN PLAINS PUSHING A PACIFIC FRONT INTO THE AREA LATE WEDNESDAY. HAVE INCLUDED A CHANCE OF RAINFALL WEDNESDAY INTO FRIDAY ASSOCIATED WITH THIS SYSTEM. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 62 75 59 69 / 50 30 30 30 SAN ANGELO 59 72 57 70 / 50 30 30 50 JUNCTION 63 72 61 71 / 40 20 40 50 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 620 PM CDT FRI MAR 23 2007 .AVIATION...NOT MUCH CHANGE IN THE AVIATION FORECAST THAN WHAT WE HAVE SEEN THE PAST SEVERAL DAYS. WILL SEE MVFR CIGS INVADE ONCE AGAIN AFTER 06Z. GUSTY WINDS WILL CONTINUE THROUGH MUCH OF THE NIGHT WITH THE EXCEPTION OF JCT AND BBD WHERE GUSTS SHOULD SUBSIDE AFTER SUNSET. WILL ONCE AGAIN SEE LIGHT RAIN AND DRIZZLE AREAS AGAIN IN THE MORNING...BUT TIMING AND RESTRICTIONS TO VISBYS NOT CERTAIN AND WILL NOT INCLUDE AT THIS TIME. THUNDERSTORMS WILL BE INCREASING IN COVERAGE OVER THE NEXT 24 HOURS...BUT AGAIN TIMING AND LOCATIONS STILL NOT CERTAIN ENOUGH FOR A MENTION AT THIS TIME. MAY HAVE TO INCLUDE PROB OR TEMPO GROUPS IN LATTER FORECAST ONCE THESE BECOME BETTER DETERMINED. BRAZZELL && .PREV DISCUSSION... /ISSUED 300 PM CDT FRI MAR 23 2007/ SHORT TERM... UPPER CLOSED LOW IS MOVING FROM THE NORTHERN BAJA INTO NORTHERN MEXICO THIS AFTERNOON. LOW LEVEL MOISTURE IS BACKED UP ALL THE WAY TO THE NEW MEXICO MOUNTAINS WITH DEW POINTS IN THE 50S INTO SOUTHEASTERN NEW MEXICO. SOUTHWEST TEXAS AND SOUTHEASTERN NEW MEXICO ARE RELATIVELY CLOUDLESS THIS AFTERNOON IN ADVANCE OF THE UPPER LOW ALLOWING FOR GOOD AFTERNOON HEATING...A FEW THUNDERSTORMS HAVE ALREADY BEGUN FORMING OFF THE HIGHER TERRAIN IN WEST TEXAS AND SOUTHERN NEW MEXICO. THE MAIN UPPER LOW WILL BE ENTERING SOUTHWEST NEW MEXICO THIS EVENING ON A TRACK THAT PUTS IT INTO SOUTHEASTERN COLORADO BY TOMORROW MORNING. AS INDICTED ON THE LATEST RUC...NEAR 50 KNOT LLJ WILL CRANK UP OVER THE PERMIAN BASIN THIS EVENING AND GIVEN GOOD INHERENT DYNAMICS ASSOCIATED WITH THE APPROACHING UPPER LEVEL SYSTEM...SHOULD SEE ADDITIONAL CONVECTIVE ACTIVITY HEATING UP THIS EVENING AND MOVE TO THE NORTHEAST. HAVE INCLUDED A CHANCE OF SEVERE IN OUR WESTERN COUNTIES TONIGHT GIVEN THEIR CLOSE PROXIMITY TO THE ANTICIPATED STORMS. UPPER LOW WILL BEGIN BIFURCATING TOMORROW WITH THE SECOND CLOSED LOW FORMING OVER ARIZONA AND MOVING SOUTHEAST INTO NORTHERN MEXICO SUNDAY NIGHT. MAIN TROUGH AXIS WILL PROVIDE A BETTER CHANCE OF RAINFALL FOR OUR FORECAST AREA BEGINNING SUNDAY AS IT MOVES EAST. TROUGH AXIS WILL PASS THROUGH WEST CENTRAL TEXAS ON MONDAY WITH THE BEST CHANCE OF RAINFALL SUNDAY THROUGH MONDAY. LONG TERM... UPPER TROUGH AXIS FINALLY MOVES EAST OF THE AREA LATE MONDAY BRINGING THIS ROUND OF PRECIPITATION TO A CLOSE. WE WILL HAVE A BRIEF RESPITE AS UPPER RIDGING BUILDS IN BEHIND THE DEPARTING TROUGH. ANOTHER UPPER LEVEL SYSTEM WILL MOVE FROM THE CENTRAL CALIFORNIA COAST INTO THE SOUTHERN PLAINS PUSHING A PACIFIC FRONT INTO THE AREA LATE WEDNESDAY. HAVE INCLUDED A CHANCE OF RAINFALL WEDNESDAY INTO FRIDAY ASSOCIATED WITH THIS SYSTEM. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 62 75 59 69 / 50 30 30 30 SAN ANGELO MMM MMM MMM MMM / MMM MMM MMM MMM JUNCTION 63 72 61 71 / 40 20 40 50 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 27/27/99 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 300 PM CDT FRI MAR 23 2007 .SHORT TERM... UPPER CLOSED LOW IS MOVING FROM THE NORTHERN BAJA INTO NORTHERN MEXICO THIS AFTERNOON. LOW LEVEL MOISTURE IS BACKED UP ALL THE WAY TO THE NEW MEXICO MOUNTAINS WITH DEW POINTS IN THE 50S INTO SOUTHEASTERN NEW MEXICO. SOUTHWEST TEXAS AND SOUTHEASTERN NEW MEXICO ARE RELATIVELY CLOUDLESS THIS AFTERNOON IN ADVANCE OF THE UPPER LOW ALLOWING FOR GOOD AFTERNOON HEATING...A FEW THUNDERSTORMS HAVE ALREADY BEGUN FORMING OFF THE HIGHER TERRAIN IN WEST TEXAS AND SOUTHERN NEW MEXICO. THE MAIN UPPER LOW WILL BE ENTERING SOUTHWEST NEW MEXICO THIS EVENING ON A TRACK THAT PUTS IT INTO SOUTHEASTERN COLORADO BY TOMORROW MORNING. AS INDICTED ON THE LATEST RUC...NEAR 50 KNOT LLJ WILL CRANK UP OVER THE PERMIAN BASIN THIS EVENING AND GIVEN GOOD INHERENT DYNAMICS ASSOCIATED WITH THE APPROACHING UPPER LEVEL SYSTEM...SHOULD SEE ADDITIONAL CONVECTIVE ACTIVITY HEATING UP THIS EVENING AND MOVE TO THE NORTHEAST. HAVE INCLUDED A CHANCE OF SEVERE IN OUR WESTERN COUNTIES TONIGHT GIVEN THEIR CLOSE PROXIMITY TO THE ANTICIPATED STORMS. UPPER LOW WILL BEGIN BIFURCATING TOMORROW WITH THE SECOND CLOSED LOW FORMING OVER ARIZONA AND MOVING SOUTHEAST INTO NORTHERN MEXICO SUNDAY NIGHT. MAIN TROUGH AXIS WILL PROVIDE A BETTER CHANCE OF RAINFALL FOR OUR FORECAST AREA BEGINNING SUNDAY AS IT MOVES EAST. TROUGH AXIS WILL PASS THROUGH WEST CENTRAL TEXAS ON MONDAY WITH THE BEST CHANCE OF RAINFALL SUNDAY THROUGH MONDAY. .LONG TERM... UPPER TROUGH AXIS FINALLY MOVES EAST OF THE AREA LATE MONDAY BRINGING THIS ROUND OF PRECIPITATION TO A CLOSE. WE WILL HAVE A BRIEF RESPITE AS UPPER RIDGING BUILDS IN BEHIND THE DEPARTING TROUGH. ANOTHER UPPER LEVEL SYSTEM WILL MOVE FROM THE CENTRAL CALIFORNIA COAST INTO THE SOUTHERN PLAINS PUSHING A PACIFIC FRONT INTO THE AREA LATE WEDNESDAY. HAVE INCLUDED A CHANCE OF RAINFALL WEDNESDAY INTO FRIDAY ASSOCIATED WITH THIS SYSTEM. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 62 75 59 69 / 50 30 30 30 SAN ANGELO 59 72 57 70 / 50 30 30 50 JUNCTION 63 72 61 71 / 40 20 40 50 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 99/15 tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BLACKSBURG VA 143 PM EDT FRI MAR 23 2007 .AVIATION /18Z-18Z/... NO ORGANIZED OR LARGE SCALE LIFTING MECHANISMS THROUGH 18Z SAT. FRONT THAT EXTENDS FROM NEW JERSEY TO CENTRAL INDIANA WILL DRIFT SOUTH LATE TONIGHT BUT WILL STALL NORTH OF THE CWA ON SATURDAY MORNING. THIS WILL INCREASE THE CLOUDS AND CHANCE OF RAIN IN THE NORTH BUT STILL NOT A HIGH ENOUGH CHANCE TO INCLUDE A MENTION OF SHOWERS AT ANY OF THE TAF SITES. WINDS WILL DIMINISH TONIGHT AS SHALLOW SURFACE INVERSION FORMS. THIS WILL LEAD TO LOW LEVEL WIND SHEAR AT DAN...BLF...AND LWB. EVEN WITH CLOUDS INCREASING FROM THE NORTH TONIGHT CEILINGS WILL REMAIN VFR. HAVE ADDED A COUPLE OF HOURS OF FOG AT LWB JUST BEFORE SUNRISE WHEN THE SURFACE DEW POINT DEPRESSION IN THE GREENBRIER VALLEY WILL BE ABOUT 2 DEGREES. && .PREV DISCUSSION... /ISSUED 1102 AM EDT FRI MAR 23 2007/ SHORT TERM /REST OF TODAY/... RUC IS SHOWING SOME LEE TROFING AND SURFACE CONVERGENCE ALONG AND JUST EAST OF THE BLUE RIDGE THIS AFTERNOON AND EVENING. SURFACE DEWPOINTS IN THAT AREA WILL BE RISING INTO THE MID 50S BUT THAT STILL RESULTS IN CAPES OF LESS THAN 100 J/KG. DEPPER MOISTURE DOES COME INTO THE FAR NORTHERN CWA THIS AFTERNOON SO WILL LEAVE IN SLIGHT CHANCE POP. ALSO SLOWED DOWN SOUTHWARD PUSH OF POPS UNTIL LATER IN THE EVENING. RAISED HIGH TEMPERATURES A FEW DEGREES IN THE NORTHWEST NORTH CAROLINA MOUNTAINS...OTHERWISE LITTLE CHANGE FOR MAXIMUM TEMPERATURES. CLIMATE... ROANOKE AND BLUEFIELD WILL HAVE HIGH TEMPERATURES CLOSE TO RECORDS TODAY. RECORDS TODAY: ROANOKE 80/1994 LYNCHBURG 91/1907 DANVILLE 86/1966 BLACKSBURG 80/1966 BLUEFIELD 76/1978 PREV DISCUSSION... /ISSUED 658 AM EDT FRI MAR 23 2007/ UPDATE... AVIATION /12Z-12Z/... EXPECT VISUAL FLIGHT RULE CONDITIONS WITH NO LOW RESTRICTION TO CEILING OR VISIBILITY THE NEXT 12 HOURS...THROUGH 00Z. FOR THE SECOND HALF OF THE TAF PD 00Z-12Z...MVFR CONDITIONS MAY DEVELOP DEPENDING ON WHETHER OUTFLOW FROM OHIO VALLEY THUNDERSTOMRS MOVE INTO THE FORECAST AREA FROM THE NORTHWEST. SURFACE RIDGE OF HIGH PRESSURE OFF THE MID ATLANTIC COAST WILL MAINTAIN SOUTHWESTERLY WINDS OVER ALL BLACKSBURG TERMINAL FORECAST AREAS (ROANOKE...LYNCHBURG... DANVILLE...BLUEFIELD...LEWISBURG) THROUGH THE PERIOD. SOUTHWEST WINDS AT BOTH SURFACE AND ALOFT WILL CAUSE COOL FRONT (CURRENTLY EXTENDING EAST-WEST FROM NEW ENGLAND INTO THE UPPER OHIO VALLEY) TO STALL NORTH OF THE BLACKSBURG FORECAST AREA. PROXIMITY OF FRONT MAY ALLOW FOR SOME MID LEVEL CLOUDS TO SKIRT THE NORTHERN TERMINAL FORECAST POINTS SUCH AS AT LEWISBURG...ROANOKE...AND LYNCHBURG THIS MORNING...BUT ANY MID LEVEL CLOUD INTRUSION SHOULD BE RELATIVELY BRIEF AND CONFINED TO MORNING HOURS. WILL HAVE TO CLOSELY MONITOR OHIO VALLEY FOR ADDITIONAL THUNDERSTORM DEVELOPMENT LATER TODAY. THERE IS THE POTENTIAL (LOW CONFIDENCE ATTM) THAT SHRA/TSRA MAY CLIP NORTHERN PARTS OF THE BLACKSBURG FCST AREA (BLF-LWB-LYH) TONIGHT...AFT 00Z. PREV DISCUSSION... /ISSUED 426 AM EDT FRI MAR 23 2007/ SYNOPSIS... AT 06Z SFC FRONT EXTENDS FROM CENTRAL PENNSYLVANIA WEST THROUGH NORTH CENTRAL OH/IN INTO NRN MO. 1020 MB SFC HIGH WAS CENTERED OVER THE GREAT LAKES. ANOTHER HIGH (1027 MB) WAS ANCHORED ALONG THE SE CAROLINA COAST. ALL PRECIPITATION WAS MAINLY CONFINED TO THE FRONTAL BOUNDARY. SHORT TERM /TODAY/... FCST AREA REMAINS ON THE WARM SIDE OF THE FRONT...AND WITH SFC HIGH POSITIONED TO OUR SOUTH ANTICIPATE WESTERLY WIND TODAY. THIS WIND WILL AID IN STRONG DOWNSLOPE WIND COMPONENT EAST OF THE MTNS WITH ADIABATIC WARMING TAKING PLACE AREAWIDE. LL THICKNESSES SUPPORT TEMPS OF 80 DEG F EAST OF THE MTNS. ADD A COUPLE DEGREES FOR ADIABATIC EFFECTS AND TMAX LIKELY TO REACH L80S. THINK CLOUD COVER ACROSS NRN PORTIONS OF THE CWA THIS MORNING WILL NOT REALLY BE A PLAYER...CLOUDS EXPECTED TO MIX OUT BY AFTERNOON. RECORD TMAX SHOULD BE TESTED AT ROA...AND POSSIBLY BCB AND BLF...SEE CLIMO SECTION FOR RECORDS. NOT IMPRESSED BY PRECIP THREAT TODAY. MODELS WERE TOO WET YESTERDAY AND BOUNDARY NEAR THE MASON DIXON SEEMS TO BE THE PRIMARY FOCUS FOR THE DEEPER MOISTURE AND LIFT. THAT SAID...REMOVED MENTION OF POPS TODAY...EXCEPT NORTH OF I64. LONG TERM /TONIGHT THROUGH THURSDAY/... THE SFC FRONT IS NOT REALLY EXPECTED TO MAKE A BIG PUSH TO THE SOUTH UNTIL SATURDAY NIGHT AND SUNDAY. HOWEVER...RIPPLES OF LOW PRESSURE ARE EXPECTED TO MOVE EAST ALONG THE BOUNDARY OVR THE NEXT 36 HRS WITH WAVES OF SHRA/TSRA. THESE MCS FEATURES MAY SEND AN OUTFL0W OUR WAY...SO CAN`T TOTALLY RULE OUT SHRA MAKING IT THIS FAR SOUTH. MAIN THREAT OF ANY MEASURABLE RAINFALL WOULD BE ACROSS THE NRN CWA...MORE SO FOR AREAS NORTH OF I64. HPC HAS HEAVIEST QPF THREAT WELL NORTH OF THE CWA ALONG THE MASON DIXON WHERE SEVERAL INCHES OF RAIN IS LIKELY PER REPEAT SHRA/TSRA. FRONT IS PROGGED TO FINALLY BACKDOOR INTO THE AREA SUNDAY WITH NORTHEAST WINDS DRAWING COOLER DRYER AIR INTO THE FCST AREA. DEEP RH APPEARS TO BE LACKING SO POPS MINIMAL. 1035 MB SFC HIGH IS EXPECTED TO TAKE UP RESIDENCE EARLY NEXT WEEK...TO BE CENTERED OVR NJ MONDAY...THEN DRIFT SOUTH INTO THE CAROLINAS TUESDAY INTO WEDNESDAY. IT APPEARS THE ERN CWA WILL FAIR THE BEST DURING THE PD WITH DRY AIR SETTLING SOUTH THROUGH ERN VA AND INTO THE CAROLINAS. MOISTURE MAY GET HUNG UP IN THE MTNS...PER OLD FRONTAL BOUNDARY AND DEVELOPMENT OF SOUTHEAST UPSLOPE. ATTM MODELS ARE FOCUSING GREATEST RH OVR WRN NC...AND ON THE WEST SIDE OF THE MTNS (ERN TN/KY) WHERE A SOUTHWEST WIND WILL POOL MOISTURE THERE. CLIMATE... RECORDS TODAY ROANOKE 80/1994 LYNCHBURG 91/1907 DANVILLE 86/1966 BLACKSBURG 80/1966 BLUEFIELD 76/1978 && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ AVIATION...AMS va AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BLACKSBURG VA 1102 AM EDT FRI MAR 23 2007 .SHORT TERM /REST OF TODAY/... RUC IS SHOWING SOME LEE TROFING AND SURFACE CONVERGENCE ALONG AND JUST EAST OF THE BLUE RIDGE THIS AFTERNOON AND EVENING. SURFACE DEWPOINTS IN THAT AREA WILL BE RISING INTO THE MID 50S BUT THAT STILL RESULTS IN CAPES OF LESS THAN 100 J/KG. DEPPER MOISTURE DOES COME INTO THE FAR NORTHERN CWA THIS AFTERNOON SO WILL LEAVE IN SLIGHT CHANCE POP. ALSO SLOWED DOWN SOUTHWARD PUSH OF POPS UNTIL LATER IN THE EVENING. RAISED HIGH TEMPERATURES A FEW DEGREES IN THE NORTHWEST NORTH CAROLINA MOUNTAINS...OTHERWISE LITTLE CHANGE FOR MAXIMUM TEMPERATURES. && .CLIMATE... ROANOKE AND BLUEFIELD WILL HAVE HIGH TEMPERATURES CLOSE TO RECORDS TODAY. RECORDS TODAY: ROANOKE 80/1994 LYNCHBURG 91/1907 DANVILLE 86/1966 BLACKSBURG 80/1966 BLUEFIELD 76/1978 && .PREV DISCUSSION... /ISSUED 658 AM EDT FRI MAR 23 2007/ UPDATE... AVIATION /12Z-12Z/... EXPECT VISUAL FLIGHT RULE CONDITIONS WITH NO LOW RESTRICTION TO CEILING OR VISIBILITY THE NEXT 12 HOURS...THROUGH 00Z. FOR THE SECOND HALF OF THE TAF PD 00Z-12Z...MVFR CONDITIONS MAY DEVELOP DEPENDING ON WHETHER OUTFLOW FROM OHIO VALLEY THUNDERSTOMRS MOVE INTO THE FORECAST AREA FROM THE NORTHWEST. SURFACE RIDGE OF HIGH PRESSURE OFF THE MID ATLANTIC COAST WILL MAINTAIN SOUTHWESTERLY WINDS OVER ALL BLACKSBURG TERMINAL FORECAST AREAS (ROANOKE...LYNCHBURG... DANVILLE...BLUEFIELD...LEWISBURG) THROUGH THE PERIOD. SOUTHWEST WINDS AT BOTH SURFACE AND ALOFT WILL CAUSE COOL FRONT (CURRENTLY EXTENDING EAST-WEST FROM NEW ENGLAND INTO THE UPPER OHIO VALLEY) TO STALL NORTH OF THE BLACKSBURG FORECAST AREA. PROXIMITY OF FRONT MAY ALLOW FOR SOME MID LEVEL CLOUDS TO SKIRT THE NORTHERN TERMINAL FORECAST POINTS SUCH AS AT LEWISBURG...ROANOKE...AND LYNCHBURG THIS MORNING...BUT ANY MID LEVEL CLOUD INTRUSION SHOULD BE RELATIVELY BRIEF AND CONFINED TO MORNING HOURS. WILL HAVE TO CLOSELY MONITOR OHIO VALLEY FOR ADDITIONAL THUNDERSTORM DEVELOPMENT LATER TODAY. THERE IS THE POTENTIAL (LOW CONFIDENCE ATTM) THAT SHRA/TSRA MAY CLIP NORTHERN PARTS OF THE BLACKSBURG FCST AREA (BLF-LWB-LYH) TONIGHT...AFT 00Z. PREV DISCUSSION... /ISSUED 426 AM EDT FRI MAR 23 2007/ SYNOPSIS... AT 06Z SFC FRONT EXTENDS FROM CENTRAL PENNSYLVANIA WEST THROUGH NORTH CENTRAL OH/IN INTO NRN MO. 1020 MB SFC HIGH WAS CENTERED OVER THE GREAT LAKES. ANOTHER HIGH (1027 MB) WAS ANCHORED ALONG THE SE CAROLINA COAST. ALL PRECIPITATION WAS MAINLY CONFINED TO THE FRONTAL BOUNDARY. SHORT TERM /TODAY/... FCST AREA REMAINS ON THE WARM SIDE OF THE FRONT...AND WITH SFC HIGH POSITIONED TO OUR SOUTH ANTICIPATE WESTERLY WIND TODAY. THIS WIND WILL AID IN STRONG DOWNSLOPE WIND COMPONENT EAST OF THE MTNS WITH ADIABATIC WARMING TAKING PLACE AREAWIDE. LL THICKNESSES SUPPORT TEMPS OF 80 DEG F EAST OF THE MTNS. ADD A COUPLE DEGREES FOR ADIABATIC EFFECTS AND TMAX LIKELY TO REACH L80S. THINK CLOUD COVER ACROSS NRN PORTIONS OF THE CWA THIS MORNING WILL NOT REALLY BE A PLAYER...CLOUDS EXPECTED TO MIX OUT BY AFTERNOON. RECORD TMAX SHOULD BE TESTED AT ROA...AND POSSIBLY BCB AND BLF...SEE CLIMO SECTION FOR RECORDS. NOT IMPRESSED BY PRECIP THREAT TODAY. MODELS WERE TOO WET YESTERDAY AND BOUNDARY NEAR THE MASON DIXON SEEMS TO BE THE PRIMARY FOCUS FOR THE DEEPER MOISTURE AND LIFT. THAT SAID...REMOVED MENTION OF POPS TODAY...EXCEPT NORTH OF I64. LONG TERM /TONIGHT THROUGH THURSDAY/... THE SFC FRONT IS NOT REALLY EXPECTED TO MAKE A BIG PUSH TO THE SOUTH UNTIL SATURDAY NIGHT AND SUNDAY. HOWEVER...RIPPLES OF LOW PRESSURE ARE EXPECTED TO MOVE EAST ALONG THE BOUNDARY OVR THE NEXT 36 HRS WITH WAVES OF SHRA/TSRA. THESE MCS FEATURES MAY SEND AN OUTFL0W OUR WAY...SO CAN`T TOTALLY RULE OUT SHRA MAKING IT THIS FAR SOUTH. MAIN THREAT OF ANY MEASURABLE RAINFALL WOULD BE ACROSS THE NRN CWA...MORE SO FOR AREAS NORTH OF I64. HPC HAS HEAVIEST QPF THREAT WELL NORTH OF THE CWA ALONG THE MASON DIXON WHERE SEVERAL INCHES OF RAIN IS LIKELY PER REPEAT SHRA/TSRA. FRONT IS PROGGED TO FINALLY BACKDOOR INTO THE AREA SUNDAY WITH NORTHEAST WINDS DRAWING COOLER DRYER AIR INTO THE FCST AREA. DEEP RH APPEARS TO BE LACKING SO POPS MINIMAL. 1035 MB SFC HIGH IS EXPECTED TO TAKE UP RESIDENCE EARLY NEXT WEEK...TO BE CENTERED OVR NJ MONDAY...THEN DRIFT SOUTH INTO THE CAROLINAS TUESDAY INTO WEDNESDAY. IT APPEARS THE ERN CWA WILL FAIR THE BEST DURING THE PD WITH DRY AIR SETTLING SOUTH THROUGH ERN VA AND INTO THE CAROLINAS. MOISTURE MAY GET HUNG UP IN THE MTNS...PER OLD FRONTAL BOUNDARY AND DEVELOPMENT OF SOUTHEAST UPSLOPE. ATTM MODELS ARE FOCUSING GREATEST RH OVR WRN NC...AND ON THE WEST SIDE OF THE MTNS (ERN TN/KY) WHERE A SOUTHWEST WIND WILL POOL MOISTURE THERE. CLIMATE... RECORDS TODAY ROANOKE 80/1994 LYNCHBURG 91/1907 DANVILLE 86/1966 BLACKSBURG 80/1966 BLUEFIELD 76/1978 && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ UPDATE... SHORT TERM...AMS CLIMATE...AMS va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 147 AM EDT FRI MAR 23 2007 .AVIATION /06Z-06Z/... EXPECT VISUAL FLIGHT RULE CONDITIONS WITH NO LOW RESTRICTION TO CEILING OR VISIBILITY EXPECTED THROUGH THE NEXT 24 HOUR TERMINAL FORECAST PERIOD ENDING 06Z SATURDAY. SURFACE RIDGE OF HIGH PRESSURE OFF THE MID ATLANTIC COAST WILL MAINTAIN SOUTHWESTERLY WINDS OVER ALL BLACKSBURG TERMINAL FORECAST AREAS (ROANOKE...LYNCHBURG... DANVILLE...BLUEFIELD...LEWISBURG) THROUGH THE PERIOD. SOUTHWEST WINDS AT BOTH SURFACE AND ALOFT WILL CAUSE COOL FRONT (CURRENTLY EXTENDING EAST-WEST FROM NEW ENGLAND INTO THE UPPER OHIO VALLEY) TO STALL NORTH OF THE BLACKSBURG FORECAST AREA. PROXIMITY OF FRONT MAY ALLOW FOR SOME MID LEVEL CLOUDS TO SKIRT THE NORTHERN TERMINAL FORECAST POINTS SUCH AS AT LEWISBURG...ROANOKE...AND LYNCHBURG THIS MORNING...BUT ANY MID LEVEL CLOUD INTRUSION SHOULD BE RELATIVELY BRIEF AND CONFINED TO MORNING HOURS. && .PREV DISCUSSION... /ISSUED 911 PM EDT THU MAR 22 2007/ SHORT TERM /REST OF TONIGHT/... ALREADY SENT EARLIER UPDATE TO LOWER POPS BACK TO CHANCE ACROSS THE NW AND APPEARS BASED ON RADAR MAY BE ABLE TO REDUCE A BIT MORE WITH THE EVENING UPDATE. LATEST ANALYSIS SHOWING WEAK MID LEVEL S/W TROF ZIPPING BY TO THE NORTH TAKING MAJORITY OF ORGANIZED SHRA NORTH...WHILE INSTABILITY STILL LACKING ACROSS THE CWA. IN THE WAKE OF THIS FEATURE APPEARS WEAK SUBSIDENCE TO PROVIDE A BREAK IN SHRA BEFORE NEXT WAVE LIFTING NE OUT OF THE MID MISS VALLEY CAUSES ANOTHER SWATH OF SHRA/TSRA TO DEVELOP INTO THE OHIO VALLEY OVERNIGHT. MOST MODELS HAVE THE MAJORITY OF THIS LIFT NORTH OF THE REGION WITH ONLY THE RUC/NAM PRODUCING SPOTTY COVERAGE GREENBRIER VALLEY/VA HIGHLANDS. THINK BEST CHANCE OF A SHRA LIKELY IN THE NEXT FEW HOURS BEFORE WARM ADVECTION PUSHES CONVERGENCE AXIS BACK NORTH. THUS TRIMMING POPS BACK TO SLIGHT CHANCE/ISOLATED NATURE EXTREME NW AND BASICALLY GOING DRY UNDER A MIX OF MID/HIGH DEBRIS CLOUDS INCLUDING SPOTTY STRATO-CU ELSEWHERE OVERNIGHT. GIVEN SOME MIXING AND CLOUDS OVERNIGHT PLAN TO RAISE LOWS SOME BUT OVERALL JUST BELOW MOS SINCE DEWPOINTS STILL SLOW TO RECOVER IN A FEW LOCATIONS. ALSO LOWERING WIND GUSTS RIDGES PER LESS OVERTURNING WITH LOSS OF HEATING AND CLOUDS OVERNIGHT. && PREV DISCUSSION... /ISSUED 643 PM EDT THU MAR 22 2007/ UPDATE... BASED ON CURRENT RADAR TRENDS/WEAK INSTABILITY ACROSS THE NW WILL UPDATE TO LOWER POPS BACK TO CHANCE THIS EVENING/OVERNIGHT NW W/OUT THUNDER AS BEST SUPPORT PASSES NORTH. ALSO WITH SHRA HAVING A TOUGH TIME CROSSING THE NW SLOPES...WILL CUT POPS FARTHER SOUTH INTO SW VA WHERE DEWPOINTS REMAIN RATHER LOW EARLY THIS EVENING. ALSO TWEAKED SKY COVER SOME...OTRW REMAINDER UNCHANGED FOR NOW. UPDATED PRODUCTS OUT SHORTLY. && PREV DISCUSSION... /ISSUED 326 PM EDT THU MAR 22 2007/ SHORT TERM /TONIGHT THROUGH FRIDAY/... AS A COLD FRONT DROPS SOUTHWARD TOWARDS REGION...A WARM SOUTHERLY FLOW WILL PUSH SOME RICHER MOISTURE INTO OUR AREA TONIGHT. REGIONAL RADAR SHOWED A BAND OF MAINLY ELEVATED PRE-FRONTAL CONVECTION JUST TO OUR WEST FROM WESTERN NEW YORK SOUTHWARD INTO THE OHIO VALLEY. THIS PRE-FRONTAL BAND OF CONVECTION IS MOVING WELL OUT AHEAD OF THE DYNAMICS AS THE MAIN SHORT WAVE WILL PASS THRU THE SOUTHERN GREAT LAKES REGION. IT`S ANTICIPATED THAT THIS CONVECTION SHOULD WEAKEN AS IT MARCHES EAST INTO OUR REGION. THERE MAY BE A GUSTY THUNDERSTORM THIS EVENING THAT REACHES OUR WESTERN SLOPES AREAS OF SOUTHEAST WEST VIRGINIA- ESPECIALLY WESTERN GREENBRIER COUNTY. KEPT THE HIGHEST POPS IN THE FAR NORTHWEST CWA FOR TONIGHT. PLAYED TEMPERATURES CLOSE TO NAM MOS VALUES. UNDERCUT DEW POINTS TONIGHT. SFC FRONT MAKES IT TO NEAR THE MASON-DIXON LINE BY FRIDAY MORNING...AND THEN ANOTHER SHORT WAVE- THE ONE MOVG INTO THE DAKOTAS...PUSHES THE FRONT TO NEAR THE NORTHERN EDGE OF THE CWA BY FRIDAY EVENING. KEPT POPS MAINLY IN THE NORTHERN HALF OF THE CWA FOR FRIDAY CLOSEST TO THE FRONT- HIGHEST IN SE WV. AGAIN...STAYED CLOSE TO NAM MOS TEMPS. LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... THE SHORT WAVE ON FRIDAY IS PROGGED TO MOVE THE FRONT SOUTHWARD AS A BACK DOOR FRONT INTO THE CWA FRIDAY NIGHT...AND THERE IS EVEN A SFC REFLECTION OF THE WAVE ALONG THE FRONT. THIS WILL BRING A GOOD CHC FOR PRECIP FRIDAY NIGHT- BUT STILL MAINLY IN NRN SECTIONS AS THE FRONT MAKES IT TO ABOUT THE ROA/LYH AREAS. WITH THIS SOUTHWARD MVMNT COMING OVERNIGHT...THERE IS USUALLY A LITTLE BETTER SOUTHWARD PUSH THAN MODELS SHOW THOUGH...SO IT WILL LIKELY MAKE IT THE NC/VA BORDER IF NOT FURTHER. THIS FRONT WILL BE STALLED ACROSS THE CWA SAT MORNING...AND THEN LIFT NORTHEAST AS A WARM FRONT...AND WILL PROVIDE A GOO SFC CONVERGENCE ZONE FOR CONVECTIVE DEVELOPMENT. I HAVE RAISED POPS FOR SAT...AND INCLUDED TSTMS IN THE AFTERNOON. I KEPT A FEW LINGERING SHOWERS IN THE MTNS SAT NIGHT-MAINLY SE WV. SHOULD BE MILD TEMPS WITH HIGH DEWPOINTS IN THE WARM SECTOR. YET ANOTHER STRONGER SHORT WAVE MOVES THRU THE GREAT LAKES REGION SUNDAY AND PUSHES THE FRONT WELL SOUTH OF THE CWA. HAVE KEPT CHC POPS IN SUNDAY FOR THIS FRONTAL PASSAGE- CHC IN THE MTNS AND SLIGHT CHC FURTHER EAST. HIGH PRESSURE BUILDS DOWN THE EAST COAST MONDAY...WHILE THE SW RETURN FLOW WEST OF THE APPALACHIANS MOVES A WARM FRONT NORTHEAST THRU THE OHIO VALLEY. I HAVE SLIGHT CHC OF SHOWERS IN THE MTNS MONDAY FOR THIS WARM FRONT. FINALLY...WE HAVE ANOTHER COLD FRONT PROGGED TO MOVE THRU THE FORECAST AREA LATE TUE OR WED. LOOKS LIKE GOOD SW FLOW OF MOISTURE AHEAD OF THIS FRONT...SO I HAVE FAIRLY HIGH CHC POPS TUE WEST OF THE BLUE RIDGE FOR SHOWERS AHEAD OF THIS FRONT. HIGH PRESSURE BUILDS INTO THE AREA WEDNESDAY WITH FAIR WEATHER. ONCE AGAIN...RETURN FLOW AND A WARM FRONT MAY BRING MORE SHOWERS TO THE MTNS THURSDAY- BUT JUST HAVE A LOW CHC AND MOST OF THE FORECAST AREA SHOULD HAVE FAIR WEATHER. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ AVIATION...WERT va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 911 PM EDT THU MAR 22 2007 .SHORT TERM /REST OF TONIGHT/... ALREADY SENT EARLIER UPDATE TO LOWER POPS BACK TO CHANCE ACROSS THE NW AND APPEARS BASED ON RADAR MAY BE ABLE TO REDUCE A BIT MORE WITH THE EVENING UPDATE. LATEST ANALYSIS SHOWING WEAK MID LEVEL S/W TROF ZIPPING BY TO THE NORTH TAKING MAJORITY OF ORGANIZED SHRA NORTH...WHILE INSTABILITY STILL LACKING ACROSS THE CWA. IN THE WAKE OF THIS FEATURE APPEARS WEAK SUBSIDENCE TO PROVIDE A BREAK IN SHRA BEFORE NEXT WAVE LIFTING NE OUT OF THE MID MISS VALLEY CAUSES ANOTHER SWATH OF SHRA/TSRA TO DEVELOP INTO THE OHIO VALLEY OVERNIGHT. MOST MODELS HAVE THE MAJORITY OF THIS LIFT NORTH OF THE REGION WITH ONLY THE RUC/NAM PRODUCING SPOTTY COVERAGE GREENBRIER VALLEY/VA HIGHLANDS. THINK BEST CHANCE OF A SHRA LIKELY IN THE NEXT FEW HOURS BEFORE WARM ADVECTION PUSHES CONVERGENCE AXIS BACK NORTH. THUS TRIMMING POPS BACK TO SLIGHT CHANCE/ISOLATED NATURE EXTREME NW AND BASICALLY GOING DRY UNDER A MIX OF MID/HIGH DEBRIS CLOUDS INCLUDING SPOTTY STRATO-CU ELSEWHERE OVERNIGHT. GIVEN SOME MIXING AND CLOUDS OVERNIGHT PLAN TO RAISE LOWS SOME BUT OVERALL JUST BELOW MOS SINCE DEWPOINTS STILL SLOW TO RECOVER IN A FEW LOCATIONS. ALSO LOWERING WIND GUSTS RIDGES PER LESS OVERTURNING WITH LOSS OF HEATING AND CLOUDS OVERNIGHT. && .PREV DISCUSSION... /ISSUED 739 PM EDT THU MAR 22 2007/ AVIATION /00Z-24Z/... SHOWERS ARE DISSIPATING OVER SE WV ATTM...AND DO NOT THINK LWB WILL BE ADVERSELY IMPACTED WITH IT. OVERALL...VFR CONDITIONS ARE GOING TO CONTINUE THIS PERIOD...WITH MID/HIGH CLOUDS CREATING A VFR CIG. LOW LEVEL WINDS WILL INCREASE OUT OF THE WEST...CREATING SOME LOW LEVEL WIND SHEAR FOR A SHORT PERIOD OF TIME AT LWB LATE TONIGHT/EARLY FRIDAY. WEST WINDS WILL GUST FROM LATE MORNING/EARLY AFTERNOON ACROSS THE MOUNTAINS. PREV DISCUSSION... /ISSUED 643 PM EDT THU MAR 22 2007/ UPDATE... BASED ON CURRENT RADAR TRENDS/WEAK INSTABILITY ACROSS THE NW WILL UPDATE TO LOWER POPS BACK TO CHANCE THIS EVENING/OVERNIGHT NW W/OUT THUNDER AS BEST SUPPORT PASSES NORTH. ALSO WITH SHRA HAVING A TOUGH TIME CROSSING THE NW SLOPES...WILL CUT POPS FARTHER SOUTH INTO SW VA WHERE DEWPOINTS REMAIN RATHER LOW EARLY THIS EVENING. ALSO TWEAKED SKY COVER SOME...OTRW REMAINDER UNCHANGED FOR NOW. UPDATED PRODUCTS OUT SHORTLY. PREV DISCUSSION... /ISSUED 326 PM EDT THU MAR 22 2007/ SHORT TERM /TONIGHT THROUGH FRIDAY/... AS A COLD FRONT DROPS SOUTHWARD TOWARDS REGION...A WARM SOUTHERLY FLOW WILL PUSH SOME RICHER MOISTURE INTO OUR AREA TONIGHT. REGIONAL RADAR SHOWED A BAND OF MAINLY ELEVATED PRE-FRONTAL CONVECTION JUST TO OUR WEST FROM WESTERN NEW YORK SOUTHWARD INTO THE OHIO VALLEY. THIS PRE-FRONTAL BAND OF CONVECTION IS MOVING WELL OUT AHEAD OF THE DYNAMICS AS THE MAIN SHORT WAVE WILL PASS THRU THE SOUTHERN GREAT LAKES REGION. IT`S ANTICIPATED THAT THIS CONVECTION SHOULD WEAKEN AS IT MARCHES EAST INTO OUR REGION. THERE MAY BE A GUSTY THUNDERSTORM THIS EVENING THAT REACHES OUR WESTERN SLOPES AREAS OF SOUTHEAST WEST VIRGINIA- ESPECIALLY WESTERN GREENBRIER COUNTY. KEPT THE HIGHEST POPS IN THE FAR NORTHWEST CWA FOR TONIGHT. PLAYED TEMPERATURES CLOSE TO NAM MOS VALUES. UNDERCUT DEW POINTS TONIGHT. SFC FRONT MAKES IT TO NEAR THE MASON-DIXON LINE BY FRIDAY MORNING...AND THEN ANOTHER SHORT WAVE- THE ONE MOVG INTO THE DAKOTAS...PUSHES THE FRONT TO NEAR THE NORTHERN EDGE OF THE CWA BY FRIDAY EVENING. KEPT POPS MAINLY IN THE NORTHERN HALF OF THE CWA FOR FRIDAY CLOSEST TO THE FRONT- HIGHEST IN SE WV. AGAIN...STAYED CLOSE TO NAM MOS TEMPS. LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... THE SHORT WAVE ON FRIDAY IS PROGGED TO MOVE THE FRONT SOUTHWARD AS A BACK DOOR FRONT INTO THE CWA FRIDAY NIGHT...AND THERE IS EVEN A SFC REFLECTION OF THE WAVE ALONG THE FRONT. THIS WILL BRING A GOOD CHC FOR PRECIP FRIDAY NIGHT- BUT STILL MAINLY IN NRN SECTIONS AS THE FRONT MAKES IT TO ABOUT THE ROA/LYH AREAS. WITH THIS SOUTHWARD MVMNT COMING OVERNIGHT...THERE IS USUALLY A LITTLE BETTER SOUTHWARD PUSH THAN MODELS SHOW THOUGH...SO IT WILL LIKELY MAKE IT THE NC/VA BORDER IF NOT FURTHER. THIS FRONT WILL BE STALLED ACROSS THE CWA SAT MORNING...AND THEN LIFT NORTHEAST AS A WARM FRONT...AND WILL PROVIDE A GOO SFC CONVERGENCE ZONE FOR CONVECTIVE DEVELOPMENT. I HAVE RAISED POPS FOR SAT...AND INCLUDED TSTMS IN THE AFTERNOON. I KEPT A FEW LINGERING SHOWERS IN THE MTNS SAT NIGHT-MAINLY SE WV. SHOULD BE MILD TEMPS WITH HIGH DEWPOINTS IN THE WARM SECTOR. YET ANOTHER STRONGER SHORT WAVE MOVES THRU THE GREAT LAKES REGION SUNDAY AND PUSHES THE FRONT WELL SOUTH OF THE CWA. HAVE KEPT CHC POPS IN SUNDAY FOR THIS FRONTAL PASSAGE- CHC IN THE MTNS AND SLIGHT CHC FURTHER EAST. HIGH PRESSURE BUILDS DOWN THE EAST COAST MONDAY...WHILE THE SW RETURN FLOW WEST OF THE APPALACHIANS MOVES A WARM FRONT NORTHEAST THRU THE OHIO VALLEY. I HAVE SLIGHT CHC OF SHOWERS IN THE MTNS MONDAY FOR THIS WARM FRONT. FINALLY...WE HAVE ANOTHER COLD FRONT PROGGED TO MOVE THRU THE FORECAST AREA LATE TUE OR WED. LOOKS LIKE GOOD SW FLOW OF MOISTURE AHEAD OF THIS FRONT...SO I HAVE FAIRLY HIGH CHC POPS TUE WEST OF THE BLUE RIDGE FOR SHOWERS AHEAD OF THIS FRONT. HIGH PRESSURE BUILDS INTO THE AREA WEDNESDAY WITH FAIR WEATHER. ONCE AGAIN...RETURN FLOW AND A WARM FRONT MAY BRING MORE SHOWERS TO THE MTNS THURSDAY- BUT JUST HAVE A LOW CHC AND MOST OF THE FORECAST AREA SHOULD HAVE FAIR WEATHER. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ UPDATE... SHORT TERM...JH va AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BLACKSBURG VA 140 PM EDT THU MAR 22 2007 .UPDATE...AVIATION. && .AVIATION /18Z-18Z/... BAND OF MVFR CONVECTION IS WEAKENING AS IT MARCHES EAST OUT OF THE OHIO VALLEY THIS AFTERNOON. SCATTERED SHOWERS AND PERHAPS THUNDER MAY PUSH INTO THE WESTERN MOUNTAINS THIS EVENING AFTER 23Z. MVFR CLOUDS/CEILINGS WITH ISOLATED IFR WILL PUSH INTO THE WESTERN SITES AFT 02Z. VFR CONDITIONS WILL CONTINUE EAST OF THE MOUNTAINS AT ROA...LYH AND DAN. SOME MVFR CLOUDS MAY SPILL OVER INTO EASTERN TAF SITES AFT 06Z. PATCHY LOW CLOUDS MAY DEVELOP OVERNIGHT AS RESIDUAL LOW LEVEL MOISTURE PERSIST. MOUNTAIN OBSCURATIONS ARE POSSIBLE TONIGHT IN THE WESTERN MOUNTAINS. && .PREV DISCUSSION... /ISSUED 1015 AM EDT THU MAR 22 2007/ UPDATE...SHORT TERM. SHORT TERM /REST OF TODAY/... HIGH PRESSURE WAS LOCATED ALONG THE ATLANTIC COAST THIS MORNING. THE HIGH CENTER WILL MOVE EAST TODAY...RESULTING IN A SOUTHWEST FLOW THIS AFTERNOON. SATELLITE AND OBS IMAGE SHOWED PATCHY LOW CLOUDS THIS MORNING...MAINLY EAST OF THE MOUNTAINS. THE WEAK COOL WEDGE WITH THIS LOW LEVEL MOISTURE WILL MIX OUT BY THIS AFTERNOON. THIS MORNING RUC 950MB MOISTURE PATTERN SUPPORTS THE IDEA OF STRATUS MIXING OUT LATE MORNING. 1000-850MB THICKNESS VALUES WITH FULL SUN WARM HIGHS CLOSE TO CURRENT FORECASTS WITH THE LOWER AND MID 70S FOR SOUTHEAST CORNER. WILL ADJUST CLOUD COVER AND HIGH TEMPERATURES FOR THIS AFTERNOON. ELECTED TO ADD THE MENTION OF THUNDER IN THE NORTHWEST CORNER. THE LINE OF CONVECTION ALONG FRONTAL BOUNDARY LOOKS STRONG ENOUGH TO WARRANT THE MENTION IN THE GREENBRIER VALLEY. HOWEVER...IN GENERAL EXPECT THE ONGOING CONVECTION TO OUR WEST TO WEAKEN SOMEWHAT AS IT APPROACHES LATER...AS IT OUTRUNS LOW LEVEL SUPPORT. FOR TONIGHT...THE MODELS BEGIN TO DIVERGE SOME ON THE FRONTAL PLACEMENT TONIGHT AS THE GFS STALLS THE FRONT FURTHER NORTH THAN THE NAM. WILL DIGEST THE 12Z RUNS BEFORE MAKING AND ADJUSTMENT TONIGHT. UPDATED ISC GRIDS AND ZONES WILL BE OUT SHORTLY. PREV DISCUSSION... /ISSUED 735 AM EDT THU MAR 22 2007/ UPDATE...AVIATION AVIATION /12Z-12Z/... LOW CLOUDS/CEILINGS EAST OF THE MOUNTAINS WILL ERODE THIS MORNING AS FLOW BECOME SOUTHWEST....THEN VFR CONDITIONS EXPECTED THIS AFTERNOON. IN THE WEST...VFR CONDITIONS ARE EXPECTED THROUGH 02Z...THEN MVFR CLOUDS/CONVECTION MAY PUSH INTO THE REGION. PREV DISCUSSION... /ISSUED 445 AM EDT THU MAR 22 2007/ SHORT TERM /TODAY/... SFC HIGH PRESSURE WAS CENTERED OFF THE NEW ENGLAND COAST WITH WEDGE OF COOL AIR ALONG AND EAST OF THE APPALACHIAN MTNS. CONSIDERABLE CLOUDINESS PREVAILED ACROSS THE ERN 2/3RDS OF THE CWA. AS THE HIGH MOVES EAST TODAY...SOUTWESTERLY WINDS WILL INCREASE ALLOWING FOR DEMISE OF COOL WEDGE AND LOW LEVEL CLOUDINESS...MOST AREAS SEEING SUN BY NOON TODAY. SOUTHWEST FLOW WILL BRING INCREASE IN INSTABILITY AND DEEPER MOISTURE. THIS INCREASE IN MOISTURE WILL FUEL CONVECTIVE ACTIVITY ENTERING THE OH VALLEY. WILL HAVE TO KEEP A CLOSE WATCH ON UPSTREAM MESOSCALE CONVECTIVE SYSTEM (MCS)...DEBRIS FROM THIS FEATURE ARRIVING LATE IN THE DAY. HAVE RAISED POPS ALONG AND NORTH OF 460 FOR THIS EVENING PER INCREASED CONFIDENCE THIS ACTIVITY WILL REACH AT LEAST THE NRN PORTIONS OF THE CWA. ATTM HAVE REFRAINED FROM MENTIONING THUNDER PER THINKING THE ACTIVITY WILL WANE AS IT MOVES OVER THE MTNS. TIMING SUGGESTS HIGHEST POPS TO OCCUR BETWEEN 00-06 UTC (8PM-2AM). LONG TERM /TONIGHT THROUGH WEDNESDAY/... SOUTHWESTERLY FLOW TO PERSIST THROUGH SATURDAY. ANY OUTFLOW THAT DRIFTS INTO THE CWA TONIGHT SHOULD MIX AWAY ON FRIDAY. SFC SYNOPTIC FRONT IS FCST TO DROP SOUTH FROM THE GREAT LAKES REGION OVER THE WEEKEND. TIMING OF THIS FEATURE DIFFERS PENDING WHICH MODEL YOU LOOK AT...RESULTING IN A VARIETY OF TEMPERATURE SOLUTIONS FOR SATURDAY. A GOOD EXAMPLE OF THIS IS LYNCHBURG...THE GFS FCSTING A TMAX OF 71 ON SATURDAY VERSUS THE NAM WHICH IS FCSTNG 83. ATTM PREFER THE FCST WE HAVE IN THE GRIDS NOW...WHICH IS SOMETHING IN BETWEEN. THINK FRONT WILL STAY NORTH OF THE CWA UNTIL AT LEAST SATURDAY NIGHT...BUT DON`T TOTALLY AGREE WITH THE REALLY WARM NAM EITHER SINCE ANTICIPATE AREAS OF CLOUDINESS PER UPSTREAM CONVECTIVE DEBIS THAT WILL BE ALONG THE FRONTAL BOUNDARY. THERE IS ALSO THE POTENTIAL FOR ANOTHER OUTFLOW TO DRIFT INTO THE AREA FRIDAY NIGHT THUS COMPLICATING THE TEMPERATURES FORECAST...IN ADDITION TO THREAT OF QPF ACROSS THE NRN CWA PER CONVECTIVE ACTIVITY. FOR NEXT WEEK...CLOSED UPPER LOW OVER THE SOUTHWESTERN CONUS IS FCST TO EJECT NE INTO THE UPPER MS VALLEY...MAIN PRECIPITATION FOCUS FOR THE MIDWEST AND GREAT LAKES. SHARP UPPER LEVEL RIDGING IS FCST DOWNSTREAM OF THIS FEATURE ACROSS OUR CWA...SFC HIGH PRESSURE WEDGING DOWN THE EAST COAST...SIMILAR TO WHAT TRANSPIRED THIS WEEK. AVIATION /08Z-06Z/... LARGE RIDGE OF SURFACE HIGH PRESSURE SITUATED OFF THE MID ATLANTIC AND NEW ENGLAND COASTLINE WILL MOVE SLOWLY EAST AND AWAY FROM THE MID ATLANTIC REGION TODAY. COOL WEDGE OF AIR ALONG AND NEAR RIDGE AXIS...AND WEAK UPSLOPE WINDS ON BACKSIDE OF SURFACE HIGH CURRENTLY HELPING TO MAINTAIN/ADVECT SOME LOWER CLOUDS NORTHWESTWARD INTO MUCH OF THE PIEDMONT TERMINAL FORECAST POINTS (DANVILLE...LYNCHBURG...AND EVENTUALLY ROANOKE). HOWEVER...DEPTH OF THIS COOL POOL IS QUITE SHALLOW...AND BOUNDARY LAYER RELATIVE HUMIDITY IS QUITE LOW. THEREFORE EXPECT TO SEE MARGINAL FLIGHT RULE RESTRICTIONS IN CEILING BUT NO RESTRICTION TO VISIBITY AT THESE FORECAST POINTS THROUGH SHORTLY AFTER DAYBREAK...FOLLOWED BY RAPID MIX OUT BY MID MORNING AS INSOLATION INCREASES...SUPPORTING MOMENTUM TRANSFER OF DRIER AND WARMER SOUTHWESTERLY WINDS ALOFT DOWN TOWARD THE SURFACE. TERMINAL FORECAST POINTS WEST OF THE BLUE RIDGE (LEWISBURG AND BLUEFIELD) SHOULD EXPERIENCE VISUAL FLIGHT RULE CONDITIONS WITH NO RESTRICTION TO VISIBILITY OR CEILING THROUGHOUT MOST IF NOT ALL OF THE TERMINAL FORECAST PERIOD DUE TO LIMITED INFLUENCE OF COOL POOL ASSOCIATED WITH EXITING SURFACE HIGH PRESSURE SYSTEM. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ UPDATE... AVIATION...07 va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 1015 AM EDT THU MAR 22 2007 .UPDATE...SHORT TERM. && .SHORT TERM /REST OF TODAY/... HIGH PRESSURE WAS LOCATED ALONG THE ATLANTIC COAST THIS MORNING. THE HIGH CENTER WILL MOVE EAST TODAY...RESULTING IN A SOUTHWEST FLOW THIS AFTERNOON. SATELLITE AND OBS IMAGE SHOWED PATCHY LOW CLOUDS THIS MORNING...MAINLY EAST OF THE MOUNTAINS. THE WEAK COOL WEDGE WITH THIS LOW LEVEL MOISTURE WILL MIX OUT BY THIS AFTERNOON. THIS MORNING RUC 950MB MOISTURE PATTERN SUPPORTS THE IDEA OF STRATUS MIXING OUT LATE MORNING. 1000-850MB THICKNESS VALUES WITH FULL SUN WARM HIGHS CLOSE TO CURRENT FORECASTS WITH THE LOWER AND MID 70S FOR SOUTHEAST CORNER. WILL ADJUST CLOUD COVER AND HIGH TEMPERATURES FOR THIS AFTERNOON. ELECTED TO ADD THE MENTION OF THUNDER IN THE NORTHWEST CORNER. THE LINE OF CONVECTION ALONG FRONTAL BOUNDARY LOOKS STRONG ENOUGH TO WARRANT THE MENTION IN THE GREENBRIER VALLEY. HOWEVER...IN GENERAL EXPECT THE ONGOING CONVECTION TO OUR WEST TO WEAKEN SOMEWHAT AS IT APPROACHES LATER...AS IT OUTRUNS LOW LEVEL SUPPORT. FOR TONIGHT...THE MODELS BEGIN TO DIVERGE SOME ON THE FRONTAL PLACEMENT TONIGHT AS THE GFS STALLS THE FRONT FURTHER NORTH THAN THE NAM. WILL DIGEST THE 12Z RUNS BEFORE MAKING AND ADJUSTMENT TONIGHT. UPDATED ISC GRIDS AND ZONES WILL BE OUT SHORTLY. && .PREV DISCUSSION... /ISSUED 735 AM EDT THU MAR 22 2007/ UPDATE...AVIATION AVIATION /12Z-12Z/... LOW CLOUDS/CEILINGS EAST OF THE MOUNTAINS WILL ERODE THIS MORNING AS FLOW BECOME SOUTHWEST....THEN VFR CONDITIONS EXPECTED THIS AFTERNOON. IN THE WEST...VFR CONDITIONS ARE EXPECTED THROUGH 02Z...THEN MVFR CLOUDS/CONVECTION MAY PUSH INTO THE REGION. PREV DISCUSSION... /ISSUED 445 AM EDT THU MAR 22 2007/ SHORT TERM /TODAY/... SFC HIGH PRESSURE WAS CENTERED OFF THE NEW ENGLAND COAST WITH WEDGE OF COOL AIR ALONG AND EAST OF THE APPALACHIAN MTNS. CONSIDERABLE CLOUDINESS PREVAILED ACROSS THE ERN 2/3RDS OF THE CWA. AS THE HIGH MOVES EAST TODAY...SOUTWESTERLY WINDS WILL INCREASE ALLOWING FOR DEMISE OF COOL WEDGE AND LOW LEVEL CLOUDINESS...MOST AREAS SEEING SUN BY NOON TODAY. SOUTHWEST FLOW WILL BRING INCREASE IN INSTABILITY AND DEEPER MOISTURE. THIS INCREASE IN MOISTURE WILL FUEL CONVECTIVE ACTIVITY ENTERING THE OH VALLEY. WILL HAVE TO KEEP A CLOSE WATCH ON UPSTREAM MESOSCALE CONVECTIVE SYSTEM (MCS)...DEBRIS FROM THIS FEATURE ARRIVING LATE IN THE DAY. HAVE RAISED POPS ALONG AND NORTH OF 460 FOR THIS EVENING PER INCREASED CONFIDENCE THIS ACTIVITY WILL REACH AT LEAST THE NRN PORTIONS OF THE CWA. ATTM HAVE REFRAINED FROM MENTIONING THUNDER PER THINKING THE ACTIVITY WILL WANE AS IT MOVES OVER THE MTNS. TIMING SUGGESTS HIGHEST POPS TO OCCUR BETWEEN 00-06 UTC (8PM-2AM). LONG TERM /TONIGHT THROUGH WEDNESDAY/... SOUTHWESTERLY FLOW TO PERSIST THROUGH SATURDAY. ANY OUTFLOW THAT DRIFTS INTO THE CWA TONIGHT SHOULD MIX AWAY ON FRIDAY. SFC SYNOPTIC FRONT IS FCST TO DROP SOUTH FROM THE GREAT LAKES REGION OVER THE WEEKEND. TIMING OF THIS FEATURE DIFFERS PENDING WHICH MODEL YOU LOOK AT...RESULTING IN A VARIETY OF TEMPERATURE SOLUTIONS FOR SATURDAY. A GOOD EXAMPLE OF THIS IS LYNCHBURG...THE GFS FCSTING A TMAX OF 71 ON SATURDAY VERSUS THE NAM WHICH IS FCSTNG 83. ATTM PREFER THE FCST WE HAVE IN THE GRIDS NOW...WHICH IS SOMETHING IN BETWEEN. THINK FRONT WILL STAY NORTH OF THE CWA UNTIL AT LEAST SATURDAY NIGHT...BUT DON`T TOTALLY AGREE WITH THE REALLY WARM NAM EITHER SINCE ANTICIPATE AREAS OF CLOUDINESS PER UPSTREAM CONVECTIVE DEBIS THAT WILL BE ALONG THE FRONTAL BOUNDARY. THERE IS ALSO THE POTENTIAL FOR ANOTHER OUTFLOW TO DRIFT INTO THE AREA FRIDAY NIGHT THUS COMPLICATING THE TEMPERATURES FORECAST...IN ADDITION TO THREAT OF QPF ACROSS THE NRN CWA PER CONVECTIVE ACTIVITY. FOR NEXT WEEK...CLOSED UPPER LOW OVER THE SOUTHWESTERN CONUS IS FCST TO EJECT NE INTO THE UPPER MS VALLEY...MAIN PRECIPITATION FOCUS FOR THE MIDWEST AND GREAT LAKES. SHARP UPPER LEVEL RIDGING IS FCST DOWNSTREAM OF THIS FEATURE ACROSS OUR CWA...SFC HIGH PRESSURE WEDGING DOWN THE EAST COAST...SIMILAR TO WHAT TRANSPIRED THIS WEEK. AVIATION /08Z-06Z/... LARGE RIDGE OF SURFACE HIGH PRESSURE SITUATED OFF THE MID ATLANTIC AND NEW ENGLAND COASTLINE WILL MOVE SLOWLY EAST AND AWAY FROM THE MID ATLANTIC REGION TODAY. COOL WEDGE OF AIR ALONG AND NEAR RIDGE AXIS...AND WEAK UPSLOPE WINDS ON BACKSIDE OF SURFACE HIGH CURRENTLY HELPING TO MAINTAIN/ADVECT SOME LOWER CLOUDS NORTHWESTWARD INTO MUCH OF THE PIEDMONT TERMINAL FORECAST POINTS (DANVILLE...LYNCHBURG...AND EVENTUALLY ROANOKE). HOWEVER...DEPTH OF THIS COOL POOL IS QUITE SHALLOW...AND BOUNDARY LAYER RELATIVE HUMIDITY IS QUITE LOW. THEREFORE EXPECT TO SEE MARGINAL FLIGHT RULE RESTRICTIONS IN CEILING BUT NO RESTRICTION TO VISIBITY AT THESE FORECAST POINTS THROUGH SHORTLY AFTER DAYBREAK...FOLLOWED BY RAPID MIX OUT BY MID MORNING AS INSOLATION INCREASES...SUPPORTING MOMENTUM TRANSFER OF DRIER AND WARMER SOUTHWESTERLY WINDS ALOFT DOWN TOWARD THE SURFACE. TERMINAL FORECAST POINTS WEST OF THE BLUE RIDGE (LEWISBURG AND BLUEFIELD) SHOULD EXPERIENCE VISUAL FLIGHT RULE CONDITIONS WITH NO RESTRICTION TO VISIBILITY OR CEILING THROUGHOUT MOST IF NOT ALL OF THE TERMINAL FORECAST PERIOD DUE TO LIMITED INFLUENCE OF COOL POOL ASSOCIATED WITH EXITING SURFACE HIGH PRESSURE SYSTEM. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ UPDATE... SHORT TERM...KK va AREA FORECAST DISCUSSION...UPDATED AVIATION DISCUSSION. NATIONAL WEATHER SERVICE SPOKANE WA 424 PM PDT FRI MAR 23 2007 .SYNOPSIS...A SERIES OF STORM SYSTEMS WILL PASS THROUGH THE REGION OVER THE NEXT FEW DAYS BRINGING PERIODS OF UNSETTLED WEATHER. && .DISCUSSION... TONIGHT...WATER VAPOR SHOWS A MOIST WESTERLY FLOW AIMED AT CENTRAL AND EASTERN WASHINGTON. SATELLITE DERIVED PRECIPITABLE WATERS WITHIN THIS BAND OF MOISTURE OFF THE COAST ARE AROUND 1.25 INCHES. A WIDE AREA OF RAINFALL ACROSS WESTERN WASHINGTON AS EVIDENT BY NWS SEATTLE RADAR WILL SLOWLY MOVE EAST TONIGHT. BASED ON THESE FACTORS AND THAT THE GFS HAS BEEN UNDER FORECASTING QPF AMOUNTS ALONG THE COAST...DECIDED TO GO WITH THE WETTER WRF MODEL SOLUTION. HOWEVER EVEN THIS MODEL HAS BEEN HAVING SOME TIMING DIFFICULTIES WITH THE PRECIP WITH THE MODEL BEING TOO SLOW. THE RUC MODEL IS ALSO WAY OFF...SO OVERALL THERE IS NO MODEL THAT IS CAPTURING THE CURRENT SITUATION THAT WELL...EXCEPT FOR PERHAPS THE UKMET BUT WITH THIS MODEL THERE IS LIMITED DATA AVAILABLE. THUS...HAD TO GO MAINLY OFF SATELLITE AND RADAR TRENDS FOR MAKING THE FORECAST FOR TONIGHT. WITH THE WESTERLY FLOW IN PLACE...RAIN SHADOWING TO AN EXTENT WILL OCCUR IN THE VALLEYS IMMEDIATELY EAST OF THE CASCADES SUCH AS THE OKANOGAN AND WENATCHEE RIVER VALLEYS. OVER NORTHEAST WASHINGTON MOUNTAINS INTO NORTH IDAHO...LOW LEVEL UPSLOPE SOUTH FLOW WILL ENHANCE PRECIPITATION. THIS SAME IDEA WILL ALSO BE TRUE FOR THE CASCADE CREST. SOME RIVER RISES ARE LIKELY IN THE NEAR FUTURE IN THESE AREAS DUE TO HIGH SNOW LEVELS NEAR 6000 FEET...AND WITH UPCOMING PRECIPITATION. JW SATURDAY THROUGH MONDAY...MODEL AGREEMENT REGARDING THE LONG-WAVE PATTERN EVOLUTION IS GOOD THIS PERIOD AND FAIR ON THE SYNOPTIC SCALE. CONFIDENCE IS LOWEST IN THE DEPICTION OF THE MOISTURE AND THERMAL FIELDS IN A RATHER MUSHY WESTERLY FLOW. SATURDAY...A SFC LOW WILL BE DEEPENING TOWARD VANCOUVER ISLAND/WRN BC. THE CWA WILL LARGELY BE MOVING INTO THE WARM SECTOR OF THE DEVELOPING FRONTAL SYSTEM...WITH VEERING WINDS FROM ABOUT THE SFC TO 700 MB AND MODEST WAA IN THE SOUTH TO SWLY FLOW. THE ATMOSPHERE REMAINS MODESTLY MOIST TOO...BEFORE A BIT OF A DRY SLOT NUDGES IN DURING AFTERNOON AND EARLY EVENING JUST AHEAD OF THE APPROACHING COLD FRONT. AT LEAST SOME MARGINAL CONDITIONAL INSTABILITY PUSHES INTO THE SOUTHEAST CWA AS WELL. THE NAM IS THE MOST AGGRESSIVE WITH THE MOISTURE AND DEPICTS SLIGHTLY STRONGER ISENTROPIC ASCENT IN THE MORNING...THUS THE NAM DEPICTS MUCH MORE PRE-FRONTAL PRECIP THAN THE GFS. THE LARGEST DIFFERENCE DOES SEEM TO BE IN THE AMOUNT OF SATURATION/MOISTENING. AS A WHOLE THE NAM IS THE MOST AMPLIFIED WITH THIS SYSTEM AND MOISTURE SEEMS A BIT OVERDONE...BUT NOT BY MUCH BECAUSE THERE IS GOOD PWAT FETCH INTO THE SYSTEM. THE 12Z GFS TRENDED SLIGHTLY TOWARD THE MOISTURE PROFILE OF THE NAM TOO. OVERALL FCST DEPICTS HIGH CHANCE TO LCL LIKELY POPS OVER THE WEST THROUGH NERN CWA...INCLUDING THE SPOKANE/C`DA AREA...IN THE MORNING. THEN IT APPEARS BEST FOCUSING SHIFTS NORTHWARD IN AN INCREASING SOUTHERLY FLOW. ALSO SOME OF THE AFOREMENTIONED DRY SLOTTING COMES UP FROM THE SOUTH FOR THE AFTERNOON. THUS I CUT BACK POPS SOME IN THE AFTERNOON OVER THE UPPER COLUMBIA BASIN/PALOUSE/SPOKANE/C`DA AREA...REDUCING THEM TO SLIGHT AND LOW CHANCE POPS. SNOW LEVELS WILL BE MODESTLY HIGH...AVERAGING IN THE 7000 TO 8000 FT RANGE. AFTERNOON TEMPS WILL BE ABOVE SEASONAL VALUES BY SOME 5-10 DEGREES...ESPECIALLY IN THE EAST-CENTRAL AND SOUTHEAST CWA. THE EXACT VALUES MAY BE HAMPERED BY THE MORE CLOUD COVER/MOISTURE...BUT ARE NONETHELESS EXPECTED TO BE MILD WHETHER THEY REACH SOME PSYCHOLOGICAL THRESHOLD OF SAY 60 DEGS OR NOT IN PLACES LIKE SPOKANE/C`DA. SATURDAY NIGHT/SUNDAY THE COLD FRONT MOVES THROUGH. THE NAM IS QUICKER THAN THE GFS MODEL BY ABOUT 3-6 HRS...AND THINKING GOES TOWARD THE SLIGHTLY SLOWER SOLUTION. EXPECTATION IS THE COLD FRONT PRECIP WILL BEGIN BETWEEN THE 00Z TO 06Z HOUR TIME FRAME. THE FRONT IS STEEPLY SLOPED FOR SOME MECHANICAL FORCING...AND HAS THE ADDED SUPPORT OF SOME AT LEAST MARGINAL JET DYNAMICS AND AT LEAST A STRETCHED VORTICITY MAX...AS WELL AS PWAT VALUES OVER 0.70 INCHES. THE WESTERLY COMPONENT OF THE WIND LOOKS MODEST SO I HAVE CUT BACK POPS IN PORTIONS OF THE WESTERN BASIN FROM THE LOW LIKELY TO HIGH CHANCE CATEGORY. THE PRECIP RISK WILL BEGIN TO DECREASE FROM THE WEST OVERNIGHT INTO SUNDAY MORNING AS THE COLD FRONT CONTINUES TO PUSH EASTWARD PASSING THROUGH MUCH OF THE CWA BY 12Z. SNOW LEVELS WILL BE LOWERING TO BTW 3000 AND 4000 FT OVER WA AND NEAR 5000 FT IN IDAHO OVERNIGHT. SUSTAINED WINDS WILL ALSO BE IN THE BREEZY CATEGORY WITH THE COLD FRONT COMING THROUGH...WITH LCL HIGHER GUSTS. THOUGH ATTM WINDS ARE NOT EXPECTED TO REACH ANY HIGHLIGHT CRITERIA BY ANY MEANS. SUNDAY...THE CONDITIONALLY UNSTABLE ATMOSPHERE BEHIND THE COLD FRONT AND THE SMALLER VORT MAXES RIDING THROUGH THE UPPER WAVE WILL MEAN A CONTINUED RISK FOR SHOWERS...ESPECIALLY IN THE AFTERNOON. SFC TEMPS WILL BE CLOSER TO SEASONAL VALUES AS 850 MB TEMPS DROP FROM NEAR 7 DEG C ON SATURDAY TO NEAR -2 DEG C ON SUNDAY AFTERNOON. ANOTHER BREEZY DAY IS EXPECTED...ESPECIALLY IN THE AFTERNOON...IN THE UNSTABLE AND MIXED ATMOSPHERE. SNOW LEVELS WILL BE AROUND 3500 TO 4500 FT IN THE AFTERNOON. SUNDAY NIGHT INTO MONDAY...A SHORTWAVE RIDGE BEGINS TO DEVELOP AND STRONGER SUBSIDENCE MOVES INTO THE REGION. THIS WILL REDUCE POPS SIGNIFICANTLY THROUGHOUT THE REGION. SOME CONDITIONAL INSTABILITY LINGERS THROUGH THE PERIOD...BUT LITTLE MOISTURE IS FOUND EXCEPT OUTSIDE OF THE MTN ZONES...SO SOME INCREASE IN AFTERNOON CLOUDINESS IS IN PLACE FOR MONDAY IN THE MTN ZONES. TEMPERATURES WILL BEGIN TO MODERATE SLIGHTLY COMPARED WITH SUNDAY`S HIGHS WITH MORE SUN AND SLIGHTLY MILDER 850 MB TEMPS. /JCOTE MONDAY NIGHT THROUGH FRIDAY...PROJECTION OF FILTERED FIVE WAVE CHART OVER NORTHERN HEMISPHERE CONTINUES TO SHOW SOME PROMISE FOR A POTENTIALLY ACTIVE WEATHER PERIOD. MONDAY NIGHT THROUGH TUESDAY NIGHT IS INFLUENCED BY A LARGE TROF THAT MOVES INLAND FROM OFF THE COAST. A NUMBER OF GFS RUNS DEPICT A SYNOPTIC SCALE LOW PRESSURE SYSTEM NESTED INSIDE THE LARGER TROF WHICH PASSES IN CLOSE PROXIMITY TO THE SOUTHERN PORTION OF THE FORECAST AREA. AS IT DOES SO IT KEEPS A FAIRLY WELL ESTABLISHED MOISTURE CONNECTION VIA A TAP STRAIGHT SOUTH NEAR MEXICO WHICH IS WELL DEPICTED IN 700MB THETA-E CONTOURS FEEDING IN A WRAP-AROUND FASHION INTO THE SURFACE LOW AS IT PASSES. HOW CLOSE THIS CLOSED LOW PASSES TO THE FORECAST AREA IS A BIG ISSUE. SOME RUNS HAVE PASSED IT FAR ENOUGH TO THE SOUTH THAT THE ENTIRE FORECAST AREA COULD BE HIGH AND DRY...BUT A NUMBER HAVE BEEN CONSISTENT ENOUGH IN THEIR DEPICTION TO KEEP THE HIGHEST POPS OF CHANCE AND LOW LIKELYS CONFINED TO THE SOUTHEAST PORTION OF THE CWA NEAR LEWISTON AND VICINITY UP INTO SHOSHONE COUNTY MONDAY NIGHT INTO TUESDAY NIGHT. ONCE THIS SURFACE LOW AND ASSOCIATED LOW PRESSURE SYSTEM EXITS TUESDAY NIGHT THE EARLIER DISCUSSED LARGER SCALE LONGWAVE TROF REMAINS OVERHEAD. SOME MINOR NUISANCE SHORTWAVES MAY CROSS THE REGION AND ADDRESS THIS WITH LOW POPS FAVORING HIGHER TERRAIN. A SECOND SYNOPTIC SCALE SYSTEM DEFINITELY WORTH MONITORING IS EXPECTED TO ORIGINATE AS A NORTHERN SIBERIAN AIRMASS MIGRATES OVER THE BEARING SEA. CYCLOGENESIS TAKES PLACE AND THE LOW PRESSURE SYSTEM STRENGTHENS AS IT PASSES DOWN OVER THE GULF OF ALASKA. THIS SYSTEM HAS POTENTIAL TO DROP DOWN OVER EASTERN WASHINGTON AND NORTHERN IDAHO FROM NORTHEAST TRAJECTORY...A CLASSIC SPRINGTIME SCENARIO. THERE HAS BEEN SOME CONTINUITY IN MODEL DEPICTIONS OF CYCLOGENESIS FORMING THIS SYSTEM BUT OF COURSE THE POINT OF ENTRY INTO THE PACIFIC NORTHWEST AND AT WHAT TIME IN THE EXTENDED IS LESS CONSISTENT. COLD POOL ALOFT CONTAINED IN THIS LOW DEMANDS RESPECT AS 500MB TEMPS ARE STILL SHOWING -40 C CONTOURS AND ASSOCIATED 1.5 IPV SURFACES SHOW LOWERING TO 750MB WHICH WOULD IMPLY QUITE A LOW TROP AND A SIGNIFICANT CONDITIONALLY UNSTABLE AIRMASS CONDUCIVE TO NOT ONLY FAIRLY GUSTY WINDS BUT A RETURN TO SPRINGTIME PRECIP TYPES SUCH AS GRAUPEL OR SOFT HAIL FOR MANY LOWER ELEVATIONS WITH SNOWFALL AT HIGHER ELEVATIONS MAKING ANY LIQUID PRECIPITATION TYPE A RARITY UNDER THIS TYPE OF AIRMASS FOR THURSDAY AND FRIDAY. OF COURSE WITH SOIL AND ROAD TEMPERATURES AS WARM AS THEY ARE NOW ACCUMULATIONS OVER LOWLANDS FOR ANY LENGTH OF TIME OVER 50 MIN OR SO WILL NOT BE AN ISSUE. WILL HAVE TO STAY ON THE LOOKOUT AND WATCH THE WATER VAPOR CHANNEL FOR SIGNIFICANT DARKENING AT THE BASE OF THIS LOW WHEN THE EVENT TIME COMES CLOSER. DPROG/DT FOR 00Z FRIDAY 30 MAR DEPICTS CONSIDERABLE SPREAD IN POINT OF ENTRY FOR THIS SECOND SYSTEM BUT DOES HAVE CONTINUITY IN BRINGING A SYSTEM OF SIMILAR BUILD IN. WITH THIS IN MIND WILL NUDGE FORECAST IN THIS GENERAL DIRECTION BUT NOT TOO DRASTICALLY IN TERMS OF KEEPING A LOW SNOW LEVEL TO ADDRESS GRAUPEL/SNOW FROM RESULTING SHOWERY CONDITIONS AND PERHAPS A BIT MORE WIND GUSTS AND SUSTAINED WINDS WITH MORE OF A WESTERLY COMPONENT. FORECAST HIGH TEMPS EXPECTED TO NOT STRAY TOO FAR FROM CLIMO BUT THE CLEARING SKIES AND NORTHERLY SURFACE WINDS ASSOCIATED WITH THE TUESDAY NIGHT INTO WEDNESDAY NIGHT SYSTEM COULD ALLOW FOR OVERNIGHT LOWS SOMEWHAT ON THE COLD SIDE OF NORMAL. THURSDAY NIGHT INTO FRIDAY HAS POTENTIAL FOR BEING A FEW DEGREES OR SO BELOW NORMAL IF THE THE SECOND MORE POWERFUL LOW COMES IN AS DEPICTED. ADDITIONALLY THUNDERSTORM MENTION FOR THURSDAY INTO FRIDAY MIGHT BE TOSSED AROUND A BIT MORE AS THE EVENT COMES CLOSER AND SOME SIGNIFICANT DROPS IN MINIMUM RELATIVE HUMIDITY AND FAIRLY MODERATE WIND OVER MOUNTAINS MIGHT OCCUR AS LOW TROPE/STRATOSPHERIC AIR MIGHT PASS LOW ENOUGH TO CAUSE IT THURSDAY AND FRIDAY...WOULD BE A PLUS IF VENTILATION IS YOUR ISSUE RATHER THAN CONTAINMENT. && .AVIATION...CLOUD COVER AND SPOTTY PRECIPITATION CONTINUE TO STREAM IN THIS EVENING INTO THE AVIATION FORECAST AREA RESULTING IN A THICKENING AND LOWERING OF CLOUD COVER BUT STILL VFR CONDITIONS REMAIN WITH PERHAPS SPOTTY MVFR NEAR PRECIP PRIMARILY DUE TO CIGS. THIS SCENARIO EXPECTED TO CONTINUE OVERNIGHT AND INTO TOMORROW UP TO 00Z SUNDAY. SOUTHERLY FLOW KICKS IN OVERNIGHT AND MAY BRING ABOUT REPEAT STRATUS FORMATION IN THE SPOKANE VICINITY IN THE 10-20Z SATURDAY TIME FRAME. && .PRELIMINARY POINT TEMPS/POPS... SPOKANE 43 60 40 51 30 53 / 50 50 70 20 10 10 COEUR D`ALENE 42 59 41 51 29 53 / 50 50 70 20 10 10 PULLMAN 41 62 44 52 31 54 / 10 20 60 40 10 10 LEWISTON 45 69 47 57 35 59 / 0 10 60 40 10 10 COLVILLE 42 60 35 51 28 53 / 50 50 70 20 20 10 SANDPOINT 40 58 35 50 31 51 / 60 60 70 40 20 10 KELLOGG 41 60 40 50 30 52 / 30 20 70 40 20 10 MOSES LAKE 45 64 39 58 30 60 / 30 30 50 10 10 10 WENATCHEE 44 61 39 56 34 59 / 20 40 50 10 10 10 OMAK 43 60 35 58 27 57 / 40 40 50 10 10 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...NONE. WA...NONE. && $$ wa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 915 PM CDT FRI MAR 23 2007 .UPDATE...LATEST 11-3.9 MICRON SATELLITE IMAGERY INDICATED AREA OF STRATUS CLOUDS HAD ERODED IN AREAS WEST OF THE MISSISSIPPI RIVER. DUE TO LIGHT WINDS AND SMALL SURFACE TEMPERATURE/DEW POINT SPREAD...FOG HAS DEVELOPED IN THIS SAME AREA...SPECIFICALLY OVER PORTIONS OF SOUTHEAST MN AND NORTHEAST IOWA. LATEST RUC SUPPORTED BOUNDARY LAYER MOISTENING DURING THE OVERNIGHT HOURS...THUS LENDING HIGH CONFIDENCE THAT FOG SHOULD CONTINUE TO THICKEN/DEVELOP IN THE AFOREMENTIONED AREAS. WILL KEEP CLOSE MONITOR ON VISIBILITIES THIS EVENING. ADDED FOG IN APPROPRIATE ZONES OF CURRENT DATA BASE...AS WELL AS RAISED DEW POINTS AND TEMPERATURES IN SOME LOCATIONS. UPDATED ZONES SHOULD BE ISSUED AROUND 0230Z THIS EVENING. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ THOMPSON wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 355 AM MDT SAT MAR 24 2007 .SHORT TERM...EVERYTHING STILL ON TRACK FOR A PERIOD OF VERY HEAVY SNOW IN THE FRONT RANGE MOUNTAINS AND PORTIONS OF THE FOOTHILLS TODAY. CURRENT WATER VAPOR LOOP SHOWS THE UPPER LOW BEGINNING TO MOVE NORTHWARD THROUGH NEW MEXICO AND CONTINUING ON THIS TRACK SHOULD TAKE THE UPPER LOW TO POINTS JUST EAST OF DENVER BY THIS AFTERNOON. THE AIRMASS IS VERY MOIST WITH PRECIPITABLE WATER VALUES ALREADY RANGING FROM AROUND 0.55 IN BOULDER TO AROUND 0.85 NEAR THE EASTERN BORDER. THESE VALUES SHOULD INCREASE A BIT MORE AS DEEPER MOISTURE MOVES IN. IN ADDITION...LAPSE RATES ARE VERY FAVORABLE WITH DEEP MOIST ADIABATIC LAPSE RATES THROUGH ALMOST THE ENTIRE COLUMN. PLATTEVILLE PROFILER ALREADY SHOWS FLOW TURNING MORE EASTERLY AND DEEPENING. AS A RESULT...SHOWERS WERE QUICKLY SPREADING IN ACROSS THE FRONT RANGE. WE SHOULD SEE NEARLY EXPLOSIVE DEVELOPMENT OF PRECIPITATION AS UPPER LEVEL SUPPORT GETS HERE AROUND DAYBREAK. HOWEVER...THERE ARE MANY QUESTIONS ON THE MESOSCALE WHICH COULD INFLUENCE AMOUNT OF PRECIP...NOT TO MENTION SNOW LEVELS. THE NAM-WRF AND RUC 13 ARE VERY SIMILAR ON THE DETAILS REGARDING THE STRENGTH OF SYSTEM AND ASSOCIATED UPSLOPE. HOWEVER...THE GFS IS MORE DISORGANIZED WITH THIS SYSTEM AND THIS COULD VERY WELL BE RELATED TO HOW ITS HANDLING CONVECTIVE ISSUES AND MASSIVE LATENT HEAT RELEASE OVER THE PLAINS. ONE WOULD LIKE TO THINK THE NAM-WRF HAS A BETTER HANDLE ON THIS AND FOLKS BACK AT NCEP AGREE THAT THE GFS IS TOO ELONGATED WITH THE UPPER LOW. HOWEVER...ITS ALSO KNOWN THAT THE NAM-WRF CAN ALSO BE A BIT TOO DEEP ON THESE SITUATIONS AS WELL. CANADIAN GIVES FURTHER CONFIDENCE IN THE NAM-WRF SOLUTION SO WILL PAINT UP A PRETTY NASTY PICTURE FOR THE FRONT RANGE MOUNTAINS. REGARDING SNOW LEVEL...FORECAST SOUNDINGS AND WET BULB ZERO LEVELS SUPPORT SNOW LEVEL GENERALLY HANGING AROUND 8000 FEET. ITS HIGHER THAN THAT NOW IN MOST SPOTS BUT INCREASING VERTICAL MOTION AND HIGHER PRECIP RATES AND MELTING SHOULD MORE THAN OFFSET ANY DAYTIME EFFECTS. CONVECTION COULD ALSO BRIEFLY LOWER SNOW LEVELS TO LESS THAN 7500 FEET AT TIMES. BOTTOM LINE...WITH THIS MUCH MOISTURE AND INSTABILITY...AND IF UPSLOPE IS AS STRONG AS ADVERTISED...WE WILL BE LOOKING AT 2-3 INCH PER HOUR SNOWFALL RATES IN THE HIGHER FOOTHILLS AND FRONT RANGE MOUNTAINS FROM MID MORNING THROUGH EARLY AFTERNOON. THIS WOULD CREATE A TRAVEL NIGHTMARE IN THE HIGH COUNTRY. ON THE PLAINS...EXPECT WIDESPREAD RAIN THROUGH THE DAY AND EVEN A FEW THUNDERSTORMS WITH APPROACH OF UPPER LOW THIS AFTERNOON. SURFACE LOW PRESSURE WILL MOVE NORTHWARD AS WELL WHICH MEANS A RIBBON OF INSTABILITY AND HIGHER DEWPOINTS WOULD PUSH BACK INTO THE FAR EASTERN SECTIONS OF THE CWA. THIS WOULD SUPPORT RISK OF ONE OR TWO SEVERE STORMS FROM LINCOLN COUNTY NORTHWARD THROUGH THE JULESBURG AREA LIKE SPC HAS PAINTED. WOULD NOT RULE OUT A TORNADO AS CONVERGENCE ZONE WOULD ACT TO INCREASE LOW LEVEL VORTICITY AND LCLS ARE GENERALLY LESS THAN 2000 FT AGL. CONDITIONS WILL QUICKLY IMPROVE THIS EVENING ACROSS THE PLAINS AND FOOTHILLS AS UPPER LOW MOVES NORTHEAST OUT OF COLORADO AND DOWNSLOPE FLOW KICKS IN. AS FAR AS AVIATION CONCERNS...WIDESPREAD IFR CONDITIONS WITH RAIN AND LOW CIGS TIL 00Z...THE CONDITIONS SHOULD RAPIDLY IMPROVE AS UPPER LOW MOVES OUT OF THE STATE. .LONG TERM...UPPER LEVEL LOW WILL MOVE RAPIDLY NE OF AREA BY 12Z SUN WITH LINGERING PCPN ONLY EXPECTED IN THE MTNS THU THE MORNING HOURS. TEMPS WILL WARM CONSIDERABLY ON SUN WITH HIGHS RISING BACK INTO THE 60S ACROSS NERN CO. FOR MON AN UPPER LEVEL RIDGE WILL BUILD OVER THE AREA WITH SWLY FLOW ALOFT DEVELOPING. THIS SHOULD LEAD TO A DRY AND MILD PTRN WITH TEMPS RISING WELL INTO THE 60S TO LOWER 70S ACROSS NERN CO BASED ON LATEST 850-700 TEMP FIELDS. BY TUE SWLY FLOW ALOFT WILL INCREASE AHEAD OF THE NEXT UPPER LEVEL SYSTEM WHICH WILL AFFECT THE AREA TUE NIGHT INTO WED. WITH INCREASING MID LEVEL MOISTURE AND IMPROVING LAPSE RATES COULD SEE SOME WDLY SCT CONVECTION IN THE MTNS TUE AFTN. OVER NERN CO STG SELY LOW LEVEL FLOW WILL DEVELOP ON TUE AS SFC LOW PRESSURE INTENSIFIES FROM CENTRAL WYOMING INTO CENTRAL COLORADO WHICH MAY ALLOW FOR DEEPER LOW LEVEL MOISTURE TO ADVECT INTO ERN PLAINS BY AFTN. TEMPS OVER NERN CO SHOULD BE SIMILAR TO MON AS 850-700 MB TEMPS ARE THE SAME. FOR TUE NIGHT A DRY LINE WILL DEVELOP NEAR THE FOOTHILLS AND THEN MOVE EAST INTO THE NERN PLAINS EVENING AS COOLING ALOFT AND SOME QG ASCENT DEVELOP OVER THE AREA. THUS COULD SEE SOME THUNDERSTORMS DEVELOP TUE EVENING ALONG DRY LINE BEFORE IT EVENTUALLY MOVES EASTWARD INTO NEBRASKA AND KANSAS. CURRENT GFS WIND FIELDS SHOW FAVORABLE SHEAR ENVIRONMENT FOR SVR STORMS SO THINGS COULD BE RATHER INTERESTING TUE EVENING ESPECIALLY JUST EAST OF THE URBAN CORRIDOR. IN THE MTNS MOISTURE WILL BE INCREASING AS MAIN UPPER LEVEL TROUGH MOVES INTO THE RGN TUE NIGHT INTO WED WITH STEEP LAPSE RATES DECENT QG ASCENT. THUS SHOULD LEAD TO A GOOD CHC OF SNOW IN THE MTNS. OVER NERN CO MAIN UPPER LEVEL LOW IS FCST TO TRACK ACROSS WYOMING WITH STG DOWNSLOPE FLOW EAST OF THE MTNS. THUS MAY SEE A BORA HIGH WIND EVENT DEVELOP LATE TUE NIGHT INTO WED ACROSS NERN CO. TEMPS ON WED WILL BE COOLER OVER NERN CO WITH READINGS DROPPING BACK INTO THE 50S. FOR WED NIGHT INTO THU WILL LIKELY SEE SOME OROGRAPHICS SNOWS IN THE MTNS AS CROSS-SECTIONS STILL SHOW QUITE A BIT OF MOISTURE WITH NWLY FLOW ALOFT. OVER NERN CO IT SHOULD REMAIN DRY WITH DOWNSLOPE NWLY LOW LEVEL FLOW IN PLACE. TEMPS ON THU SHOULD BE NEAR SEASONAL NORMALS OVER NERN CO WITH READINGS IN THE 50S. && .BOU WATCHES/WARNINGS/ADVISORIES...WINTER STORM WARNING UNTIL 6 PM THIS EVENING FOR THE FRONT RANGE FOOTHILLS...ZONES 35 AND 36. WINTER STORM WARNING UNTIL MIDNIGHT TONIGHT FOR THE FRONT RANGE MOUNTAINS...ZONES 33 AND 34. SNOW ADVISORY UNTIL 6 PM THIS EVENING FOR SOUTH PARK...ZONE 37. && $$ BARJENBRUCH/KLEYLA co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 257 AM EDT SAT MAR 24 2007 .SHORT TERM (TODAY AND TONIGHT)... OVER THE PAST FEW DAYS...SHORT-RANGE MODELS HAVE BEEN PROGRESSIVELY DIMINISHING OUR PRECIP CHANCES FOR TODAY. RUC13 INITIALIZED WELL WITH RAINFALL AND SFC TEMPS...SO FOLLOWED CLOSE TO THIS FOR POPS AND HIGH TEMPS. CURRENTLY...SFC WARM FRONTAL BOUNDARY IS LOCATED TO OUR NORTH FROM ROUGHLY COLUMBUS OH TO DES MOINES IA. STRONG 500MB RIDGE IS LOCATED ACROSS THE GULF...WITH SFC HIGH PRESSURE DOMINATING THE SERN CONUS. WEAKENING SHORTWAVE MOVING ALONG THE OHIO RIVER IS STILL GENERATING SHOWERS ACROSS OUR INDIANA COUNTIES AS IT MOVES NE AROUND THE RIDGE. THESE SHOWERS WILL CONTINUE TO MOVE NE OUT OF THE CWA...BUT WILL LIKELY CONTINUE ACROSS OUR FAR NERN CWA UNTIL ABOUT SUNRISE. THINK I WILL LEAVE OUT POPS FROM THE GRIDS AND WILL HANDLE RESIDUAL SHOWERS WITH NOWCASTS. SHORT-RANGE MODELS MOVE THE 585DM LINE NORTHWARD ACROSS THE CWA TODAY...WHICH SHOULD SUPPRESS ANY CONVECTION. THUS WILL REMOVE POPS FROM THE GRIDS TODAY THROUGH THE AFTERNOON HOURS. AND BECAUSE OF THIS...WILL INCREASE TEMPS A TAD...TOWARD RUC13 VALUES OF LOW 80S SOUTH TO UPPER 70S NORTH (SIMILAR TO A BLEND OF RAW GFS AND MET GUIDANCE VALUES). THE FRONT TO OUR NORTH IS PROGGED TO SAG A BIT SOUTHWARD TONIGHT...AND ORIENT ITSELF FROM NW TO SE...VERY CLOSE TO OUR NERN CWA BORDER. MOS POPS AT LEX RANGE FROM 20-50 PERCENT. REALLY THINK ANY ACTIVITY WOULD BE TO OUR NE...BUT WITH THE BOUNDARY SO CLOSE WILL INSERT A SLT CHC POP ACROSS THE FAR NERN CWA...MAINLY NE OF A SALEM IN TO WINCHESTER KY LINE AFTER 21Z. WILL END SHORTLY AFTER MIDNIGHT WITH THE LOSS OF HEATING. WENT SLIGHTLY BELOW RUC TEMPS FOR OVERNIGHT LOWS...WITH UPPER 50S NNE...TO MID-TO-LOW 50S DOWN SOUTH WHERE CLOUDS WILL BE LESS. AL .LONG TERM (SUNDAY THROUGH FRIDAY)... SUNDAY THROUGH MONDAY NIGHT... ANOMALOUS RIDGING MORE TYPICAL OF LATE MAY WILL BE CENTERED ACROSS THE LOWER OHIO VALLEY SUNDAY AND MONDAY. 500MB HEIGHTS WILL AVERAGE OVER 5820M ACROSS OUR CWA...WHICH IS AROUND 2.5 STANDARD DEVIATIONS ABOVE NORMAL FOR LATE MARCH. AFTERNOON TEMPERATURES...WHILE NOT SETTING RECORD HIGHS...WILL APPROACH THEM. IF AMPLE SUN IS AVAILABLE SUNDAY AND MONDAY...HIGHS IN THE LOWER 80S ARE LIKELY. THIS RIDGING WILL CORRESPOND TO TROUGHING OUT WEST. ON SUNDAY...ONE UPPER DISTURBANCE WILL BE EJECTING NORTHEASTWARD OUT OF THE MEAN TROUGH CENTERED OVER THE ROCKIES AND WILL MOVE ACROSS THE UPPER MIDWEST. THE MAIN WESTERN TROUGH WILL HANG BACK OVER THE DESERT SOUTHWEST...AND WILL HAVE TO WAIT UNTIL EARLY TUESDAY TO MOVE EAST INTO THE SOUTHERN PLAINS. THE GFS 925MB FORECAST TEMPERATURES 17C SUNDAY AFTERNOON GIVEN GOOD INSOLATION...MONDAY MAY HAVE THE WARMEST TEMPERATURES OF ALL. WITH RIDGING EXTENDING FROM THE GULF STATES ALL THE WAY TO THE GREAT LAKES...FEEL THAT BOTH SUNDAY AND MONDAY WILL BE DRY. FORECAST SOUNDINGS SHOW NO INSTABILITY SUNDAY WITH SOMEWHAT MORE UNSTABLE CONDITIONS MONDAY. HOWEVER...WITH NO NOTICEABLE TRIGGER MONDAY...WILL REMOVE POPS. TUESDAY THROUGH WEDNESDAY... A POWERFUL AND DEEP TROUGH MOVING ONTO THE WEST COAST LATE MONDAY WILL SERVE TO KICK OUT THE AFOREMENTIONED UPPER LOW ACROSS THE SOUTHERN ROCKIES INTO THE PLAINS ON TUESDAY. THIS OPEN TROUGH SHOULD WEAKEN AS IT IMPINGES UPON THE STRONG RIDGE ACROSS THE SOUTHEASTERN STATES...AND IS FORECAST TO CROSS OKLAHOMA BY BOTH THE NAM AND THE GFS TUESDAY. DEEP SOUTHERLY FLOW AND PRECIPITABLE WATER WILL INCREASE TUESDAY AND WEDNESDAY ACROSS THE LOWER OHIO VALLEY AHEAD OF THIS TROUGH AND WILL CONTINUE CHANCE WORDING FOR POPS TUESDAY AND ADD CHANCE POPS WEDNESDAY. EXPECT WELL ABOVE NORMAL TEMPERATURES TO CONTINUE THROUGH AT LEAST THURSDAY...ALTHOUGH SLIGHTLY REDUCED TUESDAY AND WEDNESDAY DUE TO ADDITIONAL CLOUD COVER. THURSDAY AND FRIDAY... TROUGHING WILL BECOME WELL ESTABLISHED ACROSS THE ROCKIES AS STRONG LOW PRESSURE MOVES NORTH ACROSS THE CENTRAL PLAINS THURSDAY. A COLD FRONT IS EXPECTED TO MOVE EAST ACROSS THE SOUTHERN PLAINS THURSDAY AND PERHAPS ACROSS THE MISSISSIPPI RIVER FRIDAY. WITH OUR FORECAST AREA STILL UNDER RIDGING...WARM TEMPERATURES AND A CHANCE OF AFTERNOON CONVECTION WILL CONTINUE THROUGH FRIDAY. JSD .AVIATION (06Z TAFS)... WITH UPPER RIDGE MOVING FURTHER NORTH...THINK THAT PRECIP CHANCES WILL BE SLIM ACROSS THE AREA THROUGH THE TAF PERIOD...AND ALL SITES SHOULD REMAIN VFR. SCATTERED MID-LEVEL CLOUDINESS IS POSSIBLE AT LEX AND SDF FROM CURRENT HOUR THROUGH MOST OF THE TAF PERIOD. JUST A FEW HIGH CLOUDS EXPECTED IN BWG`S VICINITY. IN THE 18-24 HOUR TIME FRAME...THE WARM FRONT THAT IS CURRENTLY TO OUR NORTH IS PROGGED TO SAG SOUTHWARD AND ORIENT ITSELF IN A NW TO SE FASHION THIS EVENING...COMING CLOSE TO THE LEX TAF SITE. STEEP LOW-LEVEL LAPSE RATES MAY BE INDICATIVE OF AN ISLD SHRA WITH THIS BOUNDARY...HOWEVER WILL NOT INCLUDE IN TAF AT THIS TIME. MAY BEEF UP CLOUD COVER AT LEX AFTER 21Z. EXPECTING TO BE CAPPED JUST ENOUGH THAT PRECIP WOULD STAY NE OF THE SDF AND LEX TAF SITES. WILL REMOVE LOW-LEVEL WIND SHEAR FROM TAFS BASED ON VWPS FROM REGIONAL RADARS AND MOST RECENT SDF ACARS SOUNDING. THE CURRENT AND FORECAST 1-2KFT WINDS ARE ONLY ABOUT 20-25 KTS...AND WITH SFC WINDS AT LEAST 5 KTS...LLWS CRITERIA IS NOT MET AND SHOULD NOT BE MET THROUGH THE TAF PERIOD. MAY BE A BIT GUSTY FROM 15-22Z AT SDF AND LEX...PERHAPS UP TO 15 KTS OR SO...BUT NOTHING OUT OF HAND. AL && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 425 AM EDT SAT MAR 24 2007 .SHORT TERM/TODAY THROUGH SUNDAY...BACKDOOR COLD FRONT TO AFFECT THE REGION TODAY...LATEST SFC ANALYSIS SHOWS THE BOUNDARY LOCATED APPROXIMATELY ALONG THE RTE 460 CORRIDOR...WITH LGT NNE FLOW NORTH OF THIS AND S FLOW ACRS INLAND SRN VA AND NC ZONES. MSAS 3 HR PRESSURE CHANGES ARE WEAKENING SHOWING THAT THE HIGH TO THE NORTH IS NOT REALLY PUSHING ANY FARTHER SOUTH. WITH THIS IN MIND...HAVE A VERY LARGE TEMPERATURE GRADIENT FCST FOR HIGHS TODAY...EXPECTING LOWER 80S FROM SOUTH HILL TO BERTIE COUNTY NC...WITH A HIGH AROUND 50 AT OCEAN CITY MD. NO SINGLE GUIDANCE FWC/MAV/MET WAS FOLLOWED AS NO MODEL SEEMS TO BE ACCURATELY RESOLVING THE CURRENT CONDITIONS EARLY THIS MORNING. OVERALL HAVE GONE A LITTLE BELOW MOST GUIDANCE ACRS NE ZONES AND IMMEDIATE COASTAL LOCATIONS (SUCH AS ORF) WHERE ONSHORE NE FLOW WILL PERSIST THROUGH THE DAY...AND A LITTLE ABOVE GUIDANCE FOR INLAND SRN VA ND NC ZONES. AS FOR POPS HAVE LOWERED PRECIP CHANCES A BIT FROM PREV FCST...NOT MUCH FORCING TODAY AS MAIN SHORTWAVE ENERGY (CURRENTLY SEEN ON WV SATL OUT IN MINNESOTA) WILL TRACK WELL TO OUR NORTH ACRS PA LATER THIS AFTN. IN LOWER LVLS...THE FRONT LOOKS TO BE VERY SHALLOW AND IS WEAKENING/RETREATING BACK NORTH A LITTLE. BEST CHANCES FOR PRECIP WILL BE ACRS NORTHERN AREAS MORE MOISTURE RESIDES...BUT EVEN HERE CAPPED POPS AT 40%...ALSO ADDED DRIZZLE MENTION THIS MRNG FOR ERN SHORE/NRN NECK. FARTHER SOUTH...KEPT FCST DRY THIS MORNING. HOWEVER...BY THE AFTERNOON WITH DIFFERENTIAL HEATING BOUNDARY LIKELY TO DEVELOP DUE TO STRONG LATE MARCH SUNSHINE CANNOT RULE OUT A 20 POP FOR A SHWR EVEN IN SRN ZONES. BOTH GFS AND NAM SHOW A LITTLE BIT OF SFC BASED CAPE AND NEG LI VALUES INTO THE PIEDMONT THIS AFTN...BUT WITH VERY WEAK MID LVL LAPSE RATES (H5 TO H7) KEPT THUNDER OUT OF THE FCST FOR NOW. TONIGHT/SUNDAY...GFS/NAM BOTH SHOW RIDGING AMPLIFYING ACROSS THE MISSISSIPPI VALLEY...WITH CONFLUENCE INTO ERN GREAT LAKES. THIS SHOULD ALLOW THE FRONT TO FINALLY PUSH THROUGH THE CWA IN EARNEST BY EARLY SUNDAY MORNING. CONTINUED WITH 20 POPS SW TO 50% POPS NE TONIGHT...THEN DRY ON SUNDAY. MODEL TRNDS SHOW THE SFC HIGH TO BE A FEW MB WEAKER...SO THERE MAY STILL BE SOME RESIDUAL CLOUDINESS ON SUNDAY (HAVE GONE PTLY CLOUDY/MSTLY SUNNY FAR NE SECTIONS). HIGHS WILL AGAIN SHOW A STRONG GRADIENT BETWN WARMER SW AND COOLER NE...BUT NOT AS MUCH AS SATURDAY. && .LONG TERM/MONDAY THROUGH FRIDAY...FAIRLY TYPICAL SPRINGLIKE PATTERN OF CHANGEABLE CONDITIONS. OVERALL RIDGING WILL DOMINATE ALONG THE EASTERN 1/3 OF THE NATION...BUT E OF THE APPALACHIANS WE WILL BE SUBJECT TO PERIODIC BACKDOOR COLD FRONT INTRUSIONS...THE NEXT ONE LOOKING TO BE WED NIGHT OR THURSDAY. TEMPS NEAR NORMAL MON WITH WARMING TREND TUE/WED...THEN SOMEWHAT COOLER AGAIN LATE IN THE WEEK. WITH THE UNCERTAINTY THAT FAR OUT...HAVE TRENDED TEMPS DOWN A FEW DEGREES THU/FRI BUT STILL REMAINED ABOVE NEW MEX GUIDANCE VALUES. && .AVIATION... FNTL BNDRY HAS PUSHED INTO SRN VA THE PAST CPL OF HRS. GENLY USING 03Z RUC FOR ERY PT OF TAFS (THROUGH 15Z)...WHICH SHOWED FNT SETTLING S INTO PTS OF NE NC. WND DRCTNS TRICKY INVOF PHF/ORF/ECG/RIC AFT 15Z THROUGH 06Z/25...LEANED TWD A MR ESE SOLN...W/ SPDS AOB 10 KT. SBY SHOULD KP WNDS ENE...THEN SHIFT TO SE LT. LWR CIGS SHOULD RMN SUFFICIENTLY N OF FNTL BNDRY TDA...W/ BEST SHOT AT PDS OF MVFR/IFR AT SBY. LMTD SHRA PTNTL TO SBY ATTM. && .MARINE... NOT EXACTLY THE STRNGST LLVL PUSH FM THE NE THE PAST SVRL HRS W/ FNTL BNDRY SETTLING INTO SRN WTRS. WL HV ALL AREAS W/ DRCTN N OR NE TDA...WHICH SHOULD SHIFT MR E OR SE B4 THE DAY IS OVR. CONDS RMN BLO SCA THROUGH 1ST PT OF TNGT. MR SGFNT LLVL SURGE FM THE N XPCTD LT TNGT/SUN MRNG W/ EXITING S/W OFF THE CST PUSHING FNTL BNDRY S OF WTRS. XPCTG PD OF LO END SCAS VRY LT TNGT UNTIL ERY SUN AFTN (IF NOT QUITE FOR SPDS...AT LEAST FOR SEAS ON OCN) B4 CONDS SUBSIDE LT SUN/SUN NGT. WNDSHFT FM ENE TO SSW XPCTD MON INTO TUE...W/ YET ANOTHER BKDR FNT SETTLING ACRS THE WTRS MIDWEEK. .TIDES... DEPARTURES RUNNING ABT 1/2 FOOT TO 1 FOOT BLO NRML THROUGH TDA...THEN GUID RAISES DEPARTURES TO NR NRML TNGT/SUN. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SHORT TERM...BROWN LONG TERM...BROWN AVIATION...25 MARINE...25 md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 545 AM EDT SAT MAR 24 2007 .DISCUSSION... WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW NEARLY ZONAL FLOW ACROSS THE NRN CONUS/SRN CANADA. IN THIS FAST FLOW...SHORTWAVE OF INTEREST IN THE SHORT TERM IS OVER SRN SASKATCHEWAN/ERN MT/WRN ND. RADARS SHOW DECENT COVERAGE OF ECHOES ACROSS ND/SRN MANITOBA ASSOCIATED WITH THIS SHORTWAVE...AND THERE HAVE BEEN A FEW OBS THAT HAVE INDICATED -SHRA IN NRN ND/SE SASKATCHEWAN/SRN MANITOBA TODAY. WELL TO THE W... SHORTWAVE THAT DROPPED OUT OF THE WESTERLIES 2-3 DAYS AGO OVER THE W COAST AND BECAME A MID LEVEL LOW IS NOW CENTERED JUST S OF AZ. THIS SYSTEM WILL BE OF INTEREST TO FCST HERE LATE IN THE UPCOMING WEEKEND AS IT GETS KICKED NE BY NEXT TROF APPROACHING THE W COAST. TODAY...WILL KEEP A SLIGHT CHC OF RAIN IN THIS MORNING FOR THE NRN TIER OF THE FCST AREA AS THE SHORTWAVE FROM NRN MN MOVES ACROSS THE FCST AREA. OTHERWISE...MODELS SHOW GOOD DRYING/SUBSIDENCE WITH MID-LVL RDGG IN THE WAKE OF SHORTWAVE SO WOULD EXPECT SKIES TO CLEAR FROM W TO E IN THE AFTERNOON. WITH WEAK SFC HIGH PRES OVER THE AREA...EXPECT LAKE BREEZE FORMATION THIS AFTERNOON NEAR LAKE SUPERIOR AND LAKE MICHIGAN TO KEEP TEMPS COOLER THERE. MIXING TO AROUND 850 MB ON FCST SOUNDINGS SHOULD YIELD HIGHS IN THE UPPER 50S TO LOWER 60S OVER THE WRN INTERIOR. TONIGHT...SFC RDG AND ASSOC VERY DRY AIRMASS IN PLACE OVER THE AREA(PWAT AOB 0.25 INCH) AND LIGHT WINDS SHOULD ALLOW FOR FAVORABLE RADIATIONAL COOLING CONDITIONS INTO THE EARLY OVERNIGHT AS TEMPS DROP INTO THE LOWER 30S PER MOS GUIDANCE. LOOK FOR INCREASING CLOUDS AFTER 06Z HOWEVER AS WINDS BECOME SE ON BACKSIDE OF RDG. HIGHER DWPNTS INTO THE LOW TO MID 30S ADVECTING OVER LAKE MICHIGAN IN A SE FLOW COULD RESULT IN PATCHY FOG FOR CENTRAL AND ERN COUNTIES AFTER MIDNIGHT. SE DOWNSLOPE WINDS LATE FOR FAR WEST COULD BRING TEMPS UP SOME BEFORE SUNRISE. SUN INTO SUN NIGHT...MDLS ARE IN GENERAL AGREEMENT LIFTING A SHRTWV...REMNANTS OF A CLOSED LOW OVER THE SW U.S...INTO THE WRN GREAT LAKES. THE 00Z UKMET IS STILL SLOWER WITH THE SYSTEM THAN THE GFS/CANADIAN AND NAM. GENERALLY FOLLOWED CONSENSUS OF GFS/NAM AND CANADIAN FOR DETAILS. INITIAL SHRA/TSRA COULD DEVELOP BY SUN MORNING OVER WI BDR COUNTIES WITH STRONG WAA AT NOSE OF 30-40 KT 850 MB JET AND PWAT VALUES INCREASING TO GREATER THAN AN INCH. 850 MB THETA-E RDG ALSO MOVES IN FROM THE W ALONG WITH DECREASING 850-500 MB THETA-E LAPSE RATES AND UPR DIFLUENCE AHEAD OF SHORTWAVE TROF. SCT STORMS FORMING IN THE SW FCST AREA IN THE MORNING WILL SPREAD NE ACROSS THE CWFA IN THE AFTERNOON. DEEP Q-VECT CONVERGENCE JUST AHEAD OF THE SHORTWAVE SPREADS ACROSS THE FCST AREA SUN NIGHT SUPPORTING LIKELY POPS ACROSS THE CWFA. ELEVATED CAPE VALUES OF 500-1000 J/KG OFF MODEL SNDGS ALONG WITH DEEP LYR SHEAR IN EXCESS OF 35 KT AND SRH APPROACHING 300 M2/S2 COULD SUPPORT SOME ELEVATED SUPERCELLS. SPC DAY 2 CONVECTIVE OUTLOOK HAS MUCH OF THE WEST AND SCNTRL FCST AREA IN A SLIGHT RISK FOR SVR STORMS. WET-BULB ZERO HEIGHTS IN 7-8 KFT RANGE WOULD ARGUE FOR LARGE HAIL AS THE BIGGEST THREAT ESPECIALLY AS LOW-LEVELS BECOME MORE STABLE BY LATE AFT AND EVENING. BRIEF HEAVY DOWNPOURS WILL BE LIKELY AS WELL BUT SINCE SYSTEM SHOULD BE FAIRLY PROGRESSIVE WOULD NOT EXPECT PCPN AMOUNTS MUCH MORE THAN HALF AN INCH. MON...EXPECT SHRA/TSRA TO END OVER THE WEST EARLY AND E BY AFTERNOON AS THE SHORTWAVE DEPARTS E AND RDGING/QVECTOR DIV BUILD IN BEHIND IT. EXPECTED SUNSHINE WITH WRLY FLOW AND 900 MB TEMPS FCST NEAR 10C SHOULD ALLOW TEMPS TO CLIMB TO LOWER 60S ESPECIALLY OVER WRN FCST AREA. LINGERING SFC TROF...POSSIBLE CLOUDS AND NW FLOW EXPECTED BEHIND THE TROF COULD KEEP ERN COUNTIES IN THE LOWER 50S. MON NIGHT INTO TUE...EXPECT DRY CONDITIONS AS MID-LVL RIDGE STAYS POSITIONED OVER THE REGION. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VOSS mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 101 AM CDT SAT MAR 24 2007 .AVIATION... EXPECT MVFR CONDITIONS TO CONTINUE ACROSS WEST CENTRAL TEXAS FOR THE NEXT 24 HOURS. THUNDERSTORMS...SOME POSSIBLE SEVERE...WILL MOVE INTO WEST CENTRAL TEXAS FROM THE WEST AROUND MID MORNING. LOOK FOR STRONG SURFACE WINDS FROM THE SOUTHEAST AROUND 20 KNOTS WITH GUSTS TO 30 KNOTS TO CONTINUE FOR THE REMAINDER OF TONIGHT AND MOST OF THE DAY. 23/HUBER && .PREV DISCUSSION... /ISSUED 1015 PM CDT FRI MAR 23 2007/ UPDATE... UPDATED ZONES FOR TORNADO WATCH #73 FOR STERLING COUNTY. PREV DISCUSSION... /ISSUED 903 PM CDT FRI MAR 23 2007/ UPDATE... WILL NOT MAKE ANY CHANGES TO THE FORECAST. HAD ONE SUPERCELL MOVE ACROSS EXTREME NORTHWEST CROCKETT COUNTY. THIS STORM IS NOW OVER UPTON COUNTY. THE CHC POPS LOOK GOOD FOR TONIGHT...AS INCREASING LOW LEVEL JET MAY AID IN THE DEVELOPMENT OF SCATTERED TSTMS...MAINLY AFTER MIDNIGHT. 21 PREV DISCUSSION... /ISSUED 620 PM CDT FRI MAR 23 2007/ AVIATION...NOT MUCH CHANGE IN THE AVIATION FORECAST THAN WHAT WE HAVE SEEN THE PAST SEVERAL DAYS. WILL SEE MVFR CIGS INVADE ONCE AGAIN AFTER 06Z. GUSTY WINDS WILL CONTINUE THROUGH MUCH OF THE NIGHT WITH THE EXCEPTION OF JCT AND BBD WHERE GUSTS SHOULD SUBSIDE AFTER SUNSET. WILL ONCE AGAIN SEE LIGHT RAIN AND DRIZZLE AREAS AGAIN IN THE MORNING...BUT TIMING AND RESTRICTIONS TO VISBYS NOT CERTAIN AND WILL NOT INCLUDE AT THIS TIME. THUNDERSTORMS WILL BE INCREASING IN COVERAGE OVER THE NEXT 24 HOURS...BUT AGAIN TIMING AND LOCATIONS STILL NOT CERTAIN ENOUGH FOR A MENTION AT THIS TIME. MAY HAVE TO INCLUDE PROB OR TEMPO GROUPS IN LATTER FORECAST ONCE THESE BECOME BETTER DETERMINED. BRAZZELL PREV DISCUSSION... /ISSUED 300 PM CDT FRI MAR 23 2007/ SHORT TERM... UPPER CLOSED LOW IS MOVING FROM THE NORTHERN BAJA INTO NORTHERN MEXICO THIS AFTERNOON. LOW LEVEL MOISTURE IS BACKED UP ALL THE WAY TO THE NEW MEXICO MOUNTAINS WITH DEW POINTS IN THE 50S INTO SOUTHEASTERN NEW MEXICO. SOUTHWEST TEXAS AND SOUTHEASTERN NEW MEXICO ARE RELATIVELY CLOUDLESS THIS AFTERNOON IN ADVANCE OF THE UPPER LOW ALLOWING FOR GOOD AFTERNOON HEATING...A FEW THUNDERSTORMS HAVE ALREADY BEGUN FORMING OFF THE HIGHER TERRAIN IN WEST TEXAS AND SOUTHERN NEW MEXICO. THE MAIN UPPER LOW WILL BE ENTERING SOUTHWEST NEW MEXICO THIS EVENING ON A TRACK THAT PUTS IT INTO SOUTHEASTERN COLORADO BY TOMORROW MORNING. AS INDICTED ON THE LATEST RUC...NEAR 50 KNOT LLJ WILL CRANK UP OVER THE PERMIAN BASIN THIS EVENING AND GIVEN GOOD INHERENT DYNAMICS ASSOCIATED WITH THE APPROACHING UPPER LEVEL SYSTEM...SHOULD SEE ADDITIONAL CONVECTIVE ACTIVITY HEATING UP THIS EVENING AND MOVE TO THE NORTHEAST. HAVE INCLUDED A CHANCE OF SEVERE IN OUR WESTERN COUNTIES TONIGHT GIVEN THEIR CLOSE PROXIMITY TO THE ANTICIPATED STORMS. UPPER LOW WILL BEGIN BIFURCATING TOMORROW WITH THE SECOND CLOSED LOW FORMING OVER ARIZONA AND MOVING SOUTHEAST INTO NORTHERN MEXICO SUNDAY NIGHT. MAIN TROUGH AXIS WILL PROVIDE A BETTER CHANCE OF RAINFALL FOR OUR FORECAST AREA BEGINNING SUNDAY AS IT MOVES EAST. TROUGH AXIS WILL PASS THROUGH WEST CENTRAL TEXAS ON MONDAY WITH THE BEST CHANCE OF RAINFALL SUNDAY THROUGH MONDAY. LONG TERM... UPPER TROUGH AXIS FINALLY MOVES EAST OF THE AREA LATE MONDAY BRINGING THIS ROUND OF PRECIPITATION TO A CLOSE. WE WILL HAVE A BRIEF RESPITE AS UPPER RIDGING BUILDS IN BEHIND THE DEPARTING TROUGH. ANOTHER UPPER LEVEL SYSTEM WILL MOVE FROM THE CENTRAL CALIFORNIA COAST INTO THE SOUTHERN PLAINS PUSHING A PACIFIC FRONT INTO THE AREA LATE WEDNESDAY. HAVE INCLUDED A CHANCE OF RAINFALL WEDNESDAY INTO FRIDAY ASSOCIATED WITH THIS SYSTEM. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 59 71 57 70 / 30 30 40 50 SAN ANGELO 61 70 58 70 / 30 50 50 50 JUNCTION 59 69 58 70 / 40 50 70 50 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 23/HUBER tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPOKANE WA 315 AM PDT SAT MAR 24 2007 .SYNOPSIS...MOIST PACIFIC FLOW WILL BRING MILD AND WET WEATHER TO MUCH OF THE INLAND NORTHWEST TODAY. AN UPPER LEVEL DISTURBANCE WILL TRACK THROUGH THE AREA OVERNIGHT PUSHING A COLD FRONT THROUGH THE INLAND NORTHWEST AND EASING THE WET WEATHER THREAT. THIS DRIER WEATHER WILL GENERALLY PREVAIL THROUGH MONDAY...BUT MUCH COOLER AND WETTER WEATHER IS ON TAP FOR THE PACIFIC NORTHWEST BY TUESDAY. && .DISCUSSION... TODAY AND TONIGHT...SATELLITE PIX THIS MORNING DEPICT AN IMPRESSIVE MOISTURE TRAIN EXTENDING FROM NW OF THE HAWAIIAN ISLANDS TO SC BC. ALTHOUGH BOTH THE NAM AND GFS HANDLE THIS PLUME SIMILARLY...THEY DON`T SEEM TO BE HANDLING THE CURRENT PRECIP SITUATION ALL THAT WELL. THE LATEST RADAR MOSAICS DEPICT SOLID PRECIP EXTENDING FROM THE LOWER COLUMBIA BASIN AND INTO THE IDAHO PANHANDLE. MOST OF THIS PRECIP IS BEING GENERATED BY A COMBINATION OF MODERATE LOW-LEVEL WARM AIR ADVECTION AND MODEST ISENTROPIC ASCENT THROUGH THE 295-305K LAYER. BOTH THE GFS AND NAM SHOW A SIMILAR SW-NE ORIENTATION OF THIS MOISTURE BAND...BUT KEEP CONDENSATION PRESSURE DEFICIT VALUES FAR TOO LARGE. FORTUNATELY THE RUC SOLUTION IS HANDLING THE SITUATION QUITE WELL...BUT THIS SOLUTION ONLY EXTENDS TO 18Z AT THIS TIME. THE RUC SUGGESTS THE PLUME WILL ONLY NUDGE SLIGHTLY NORTHWARD THIS MORNING...PERHAPS EASING THE THREAT OF PRECIP OVER THE SE ZONES...BUT PRECIP OVER THE NE QUARTER OF THE CWA LOOKS LIKE A SURE BET THROUGH THE MORNING. DESPITE THE DECENT ISENTROPIC ASCENT POTENTIAL...NOT TOO SURE MUCH PRECIP WILL DEVELOP IN THE LEE OF THE CASCADES DUE TO MODERATE WESTERLY FLOW OVER THE CASCADES. LATER TODAY...WE EXPECT THIS PLUME TO SHIFT TOWARD THE CANADIAN BORDER AS THE TRAILING COLD FRONT PUSHES TOWARD THE WA COAST. THIS PLACES AN IMPRESSIVE WARM SECTOR OVER THE SOUTHERN HALF OF THE CWA AND RESULTS IN RATHER MILD TEMPS. BUFR SOUNDING AND RAW SFC TEMPS SUGGEST THE MOS NUMBERS ARE TOO LOW FOR THIS AFTERNOON AS 850 MB TEMPS PUSH ABOVE 10C OVER THE SE CORNER OF THE CWA. IN AREAS THAT SEE RAIN THROUGH MUCH OF THE DAY...IE SANDPOINT...COLVILLE...BONNERS FERRY...THE MIXING POTENTIAL WILL BE MINIMAL AND TEMPS COULD FALL AT OR BELOW MOS VALUES. BOTH THE GFS AND NAM SUGGEST A POTENT SHORTWAVE TROF WILL PUSH THROUGH THE CANADIAN ROCKIES AFTER 06Z ALLOWING THE TRAILING COLD FRONT TO TRACKTHROUGH THE INLAND NW. SIGNIFICANT LIFTING AHEAD OF THE FRONT IS EXPECTED AS MODEL CROSS SECTIONS SHOW A FRONTAL DEPTH TO AROUND 600 MBS WITH DECENT SYNOPTIC SCALE LIFTING ABOVE. STILL NOT TERRIBLY CONFIDENT IN PRECIP CHANCES IN THE LEE OF THE CASCADES AS THE 700 MB WINDS NEVER DEVIATE MUCH FROM THE WEST...BUT FARTHER EAST PRECIP CHANCES LOOK FAIRLY GOOD. THE FRONT WILL LOSE MUCH OF ITS EASTERLY MOMENTUM AS IT BECOMES INCREASINGLY PARALLEL TO THE MEAN 700-500 MB FLOW. THIS COULD LEAVE THE FRONT STALLED OVER THE PALOUSE...LEWISTON AND BLUE MOUNTAINS AFTER 06Z AND SUGGESTS THE POTENTIAL FOR DECENT QPF AMOUNTS. THE GFS SEEMS TO ACCURATELY DEPICT THIS SCENARIO...WHEREAS THE NAM IS A BIT TO PROGRESSIVE. AS FOR POST FRONTAL SHOWERS...THE CHANCES DO NOT LOOK GOOD WITH VERY LITTLE POST FRONTAL CUMULUS NOTED OVER THE PACIFIC AT THIS TIME. PERHAPS A BIGGER QUESTION FOR LATER TONIGHT WILL BE THE POST FRONTAL WIND POTENTIAL. CLIMATOLOGICALLY LATE NIGHT COLD FRONT PASSAGES SEEM TO LACK MUCH OF THE PUNCH SUGGESTED BY THE MODELS UNLESS THEY ARE VERY STRONG. THIS IS ESPECIALLY TRUE FOR THE NAM. SINCE THE UPPER LEVEL COOLING WITH THIS SYSTEM SEEMS A LITTLE LACKLUSTER AND THE TRACK OF THE SURFACE LOW IS SO FAR NORTH THE WEAKER WINDS FORECAST BY THE GFS SEEM A LITTLE MORE ACCURATE AT THIS TIME. NONETHELESS WE SHOULD SEE LOCALLY BREEZY CONDITIONS DEVELOP LATE TONIGHT. FX SUNDAY THROUGH SATURDAY...WHILE MODELS EXHIBIT RELATIVELY DECENT AGREEMENT FOR THE SUNDAY AND MONDAY PERIOD OF THE FORECAST BUILDING RATHER PRONOUNCED RIDGING ACROSS THE CWA AND REALLY DRYING OUT THE COLUMN...MODEL DISCREPANCIES REALLY BEGIN TO SHOW UP STARTING MONDAY NIGHT AND THROUGH THE BULK OF THE REST OF THE PERIOD. SUNDAY AND MONDAY ARE BASICALLY CARBON COPIES OF EACH OTHER EXCEPT THAT 850 MB TEMPERATURES JUMP ABOUT 2C FROM SUNDAY TO MONDAY ALLOWING FOR SLIGHTLY WARMER CONDITIONS ON MONDAY THAN SUNDAY AS BOTH DAYS SHOULD BE GOOD MIXING DAYS FROM AT LEAST 850 MB WITH NEARLY DRY ADIABATIC LAPSE RATES FROM THE SURFACE UP TO 700 MB. WITH WEAKER SATURATION ON MONDAY THAN SUNDAY AT THE TOP OF THE UNSTABLE LAYER...BELIEVE MONDAY WILL PROBABLY BE A BIT CLEARER...BUT LOW LEVEL INSTABILITY WITH SOUTHWESTERLY FLOW ALOFT WILL PROBABLY LEAD TO INSTABILITY SHOWERS OF RAIN AND SNOW BOTH AFTERNOONS. GIVEN THE INSTABILITY DUE TO VERY COLD AIR ALOFT...WOULD NOT BE AT ALL SURPRISED TO SEE SOME SMALL HAIL OR THUNDER EITHER DAY GIVEN MUCAPE VALUES OF A COUPLE HUNDRED J/KG OFF THE GFS. BY MONDAY NIGHT...THE NEXT 500 MB WAVE OFF THE PACIFIC HAS DEEPENED SIGNIFICANTLY AND CLOSED OFF AS IT CAME ON SHORE INTO NORTHERN CALIFORNIA. MODELS TONIGHT SEEM TO BE IN MUCH BETTER AGREEMENT FOR TRACKING THE 500 MB LOW INTO EITHER NORTHERN CALIFORNIA OR SOUTHERN OREGON BY 12Z TUESDAY. HOWEVER...THE DISCREPANCIES AMONGST THE MODELS AND ENSEMBLES ARE STILL RATHER STARK. THE ECMWF NEVER COMPLETELY CLOSES OFF THE 500 MB WAVE THROUGH MONDAY NIGHT...WHILE THE GFS AND DGEX BOTH CLOSE OFF A 500 MB LOW ON THE SOUTHERN FLANK OF THE MID-LEVEL WAVE WHILE LEAVING ANOTHER CLEARLY DISCERNIBLE LOW FARTHER TO ITS NORTH OVER SOUTHERN OREGON. THE ECMWF BEGINS TO CLOSE OFF THE LOW AFTER THIS POINT AND COMES INTO STEP WITH THE GFS ALMOST COMPLETELY THROUGH THE DAY TUESDAY...SHIFTING THE LOW NORTHEASTWARD OUT OF OREGON INTO CENTRAL IDAHO. THE DGEX TRACKS THE LOW MODESTLY FARTHER NORTHWEST. WHILE ALL THIS IS OCCURRING...A SECOND UPPER LOW BEGINS TO DIVE SOUTHWARD FROM THE GULF OF ALASKA DOWN THE PACIFIC COAST OF CANADA...LOWERING 250 MB HEIGHTS OFF OF BRITISH COLUMBIA. THIS SEEMS TO CAUSE A COMPENSATORY DROP IN 500 MB HEIGHTS OFF THE COAST AND WITH NEARLY STATIONARY SHORT WAVE RIDGING ALONG AND JUST EAST OF THE CONTINENTAL DIVIDE...SHIFTS THE ORIENTATION OF THE ASSOCIATED MID AND UPPER WAVES TO A NEGATIVE TILT. BY DOING SO...THE TRACK OF THE MID-LEVEL LOW AND UPPER WAVE TAKES ON A MORE MERIDIONAL TRAJECTORY RATHER THAN ZONAL AND AS A RESULT...A STRONG UPPER JET COUPLE TRACKS DIRECTLY OVER THE TOP OF THE EASTERN PORTION OF THE CWA. THE GFS AND DGEX BOTH INDICATE NORTHEASTERLY FLOW BELOW 700 MB DEVELOPS AHEAD OF A SURFACE AND 850 MB LOW THAT SHOULD TRACK NEAR THE SOUTHEASTERN PORTION OF THE CWA IN ASSOCIATION WITH THE TRACK OF THE UPPER JET COUPLET. ADDITIONALLY...STRONG AXIS OF DEFORMATION SHOW UP AT THE SURFACE...850 MB...AND 700 MB ALONG THE EASTERN PORTION OF THE CWA FROM MONDAY NIGHT INTO TUESDAY. ALONG WITH THIS...MOISTURE TRANSPORT IN THE 290-300K LAYER AS WELL AS THE BENT BACK MONTGOMERY STREAMFUNCTION FIELDS ON THE ISOBARS AT 295K SUGGEST SIGNIFICANT ISENTROPIC ASCENT IS POSSIBLE FROM THE BLUES NORTHWARD THROUGH THE IDAHO PANHANDLE. ADDITIONALLY...AS MOISTURE IS TRANSPORTED INTO THE DRY NORTHEASTERLY FLOW...WET BULB COOLING EFFECTS SHOULD MARKEDLY COOL THE COLUMN OVERNIGHT TUESDAY NIGHT WHILE COOLING FROM RAPID ASCENT/DYNAMICAL COOLING AND ADIABATIC EXPANSION OF AIR WILL AIDE IN COOLING THE COLUMN. THIS WILL CAUSE SNOW LEVELS TO DROP RAPIDLY IN THE DEFORMATION ZONE ON THE NORTHWESTERN PERIPHERY OF THE 850 MB LOW...AND LIKELY LEAD TO A ZONE OF ACCUMULATING SNOW FOR THE LOWER ELEVATIONS NEAR TO OR JUST TO THE EAST OF SPOKANE. ADDITIONALLY...AS THE AFTERNOON TUESDAY GOES ON AND SYSTEM BEINGS TO LIFT OUT...LOW LEVEL MOISTURE HANGS AROUND BUT INSTABILITY INCREASES DUE TO DIABATIC WARMING DURING THE AFTERNOON. HOWEVER...WITH COLD AIR STILL IN PLACE ALOFT...NORTHWESTERLY FLOW INTO THE BLUE MOUNTAINS AND CAMAS PRAIRIE MAY RESULT IN AN ADDITIONAL PERIOD OF SNOW FOR THESE AREAS. THE DGEX AND GFS ARE PICKING UP ON COPIOUS QPF AMOUNTS FOR THE BLUES AND UP TO A HALF INCH OF LIQUID EQUIVALENT FOR MOST LOWER ELEVATIONS OF THE EASTERN CWA. NEEDLESS TO SAY...AM VERY GLAD THE MODELS HAVE A COUPLE DAYS TO SORT THINGS OUT...BUT 18Z AND 00Z CYCLES WERE RATHER OMINOUS FOR A SIGNIFICANT SNOW EVENT SOMEWHERE NEAR THE EASTERN PORTION OF THE CWA LATE MONDAY NIGHT INTO TUESDAY. BEYOND TUESDAY...THE NEXT UPPER LOW SHIFTS DOWN THE COAST BY THE END OF THE WEEK. THE 00Z MODELS SHIFTED ITS TRACK NORTH INTO BRITISH COLUMBIA WHEREAS EARLIER RUNS BROUGHT IT SIGNIFICANTLY FARTHER SOUTHWARD WHICH WOULD HAVE RESULTED IN SOME UNSEASONABLY COLD CONDITIONS OVER THE CWA. CURRENT FORECAST INDICATES TEMPERATURES BELOW CLIMATOLOGY...AND GIVEN LACK OF FAITH IN THE 00Z CYCLE FOR THE PERIOD...WILL NOT BE CHANGING THE CURRENT PACKAGE. /FRIES && .AVIATION...A SUBTROPICAL MOISTURE FEED WITH ORIGINS NORTH OF HAWAII WILL SPREAD RAIN AND CLOUDS INTO THE PACIFIC NORTHWEST THROUGH 06Z SUNDAY. THE MOST SIGNIFICANT RAINS WILL OCCUR OVER THE CASCADES AND THE MOUNTAINS OF NORTHEAST WASHINGTON WITH MOIST SOUTHWESTERLY FLOW. STRATOCUMULUS MAY DROP CEILINGS TO MVFR BETWEEN 10Z AND 17Z IN THE SPOKANE AND VICINITY. /GKOCH && .PRELIMINARY POINT TEMPS/POPS... SPOKANE 61 42 53 30 57 32 / 70 60 20 10 10 30 COEUR D`ALENE 60 42 53 29 56 31 / 70 70 30 10 10 30 PULLMAN 63 44 54 31 56 32 / 40 60 50 10 10 50 LEWISTON 71 47 59 35 60 34 / 20 60 40 10 10 40 COLVILLE 58 39 53 28 56 30 / 80 70 20 20 10 10 SANDPOINT 57 41 51 31 54 32 / 70 70 30 20 10 30 KELLOGG 57 40 52 30 54 31 / 70 80 80 20 10 50 MOSES LAKE 67 43 59 30 60 33 / 40 40 10 10 10 10 WENATCHEE 63 40 57 32 60 35 / 40 40 10 10 10 10 OMAK 61 39 59 27 59 30 / 60 70 10 10 10 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...NONE. WA...NONE. && $$ wa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 905 AM EDT SAT MAR 24 2007 .UPDATE... 12Z WATER VAPOR AND H4 RUC ANALYSIS CONTINUE TO SHOW THE UPPER RIDGE BUILDING FROM THE CENTRAL GULF OF MEXICO NORTHWARD ACROSS THE SOUTHEASTERN UNITED STATES. DEEP TROUGH/CLOSED LOW OVER THE SOUTHWEST CONTINUES TO SEND ROUNDS OF SHOWERS AND THUNDERSTORMS NORTHEAST ACROSS THE CENTRAL/SOUTHERN PLAIN STATES...HOWEVER THIS ACTIVITY WILL REMAIN WELL TO OUR WEST FOR THE NEXT SEVERAL DAYS WITH A CONTINUATION OF THE DRY AND WARM PATTERN OVERHEAD. LATEST SURFACE MAP SHOWS HIGH PRESSURE NOSING BACK FROM THE WESTERN ATLANTIC OVER THE FORECAST AREA. THIS HIGH WILL BE IN NO BIG HURRY TO EXIT THE REGION AND SHOULD ACTUALLY BE RE-ENFORCED BY ANOTHER RIDGE BUILDING DOWN THE EAST COAST BY VERY LATE IN THE WEEKEND. EARLY MORNING SATELLITE IMAGERY SHOWING SOME HIGHER CLOUDS OFF TO OUR WEST HAVING A BIT OF TROUBLE BREAKING EASTWARD THROUGH THE UPPER RIDGE. THESE CLOUDS ARE MAINLY THE RESULT OF SOME BROAD MID/UPPER LEVEL ISENTROPIC LIFT ALONG THE 315-325K SURFACES. THIS LIFT IS FORECAST TO REMAIN WELL TO OUR WEST THROUGH THE MAJORITY OF THE WEEKEND AND LATEST NAM RH FIELDS ARE SHOWING CONSIDERABLE DRYING OF THIS MOISTURE AS IT ATTEMPTS TO ADVECT EASTWARD ALONG THE GULF COAST DURING THE AFTERNOON AND EVENING. FOR THIS REASON...WOULD NOT EXPECT MUCH MORE THAN A FEW BANDS OF CIRRUS THROUGH THE DAYLIGHT HOURS. SOME PATCHY FOG SEEN IN THE FIRST HOUR TO TWO AFTER SUNRISE IS BURNING OFF RAPIDLY. KTLH AND KVLD WERE BOTH ABLE TO PICK UP SOME RESTRICTED VISIBILITIES FOR A PERIOD THIS MORNING WITH KVLD DOWN UNDER TWO MILES FOR A TIME. THIS FOG HAS BEEN QUITE SPOTTY AND NO SERIOUS TRAVEL CONCERNS ARE ANTICIPATED WHILE THE FOG FINISHES BURNING OFF THIS MORNING. STILL LOOKING LIKE A VERY PLEASANT...ALTHOUGH WARM AFTERNOON FOR EARLY SPRING ACROSS THE ENTIRE FORECAST AREA. TEMPERATURES HERE IN THE MID MORNING HOURS RAPIDLY CLIMBING THROUGH THE 60S ON THE WAY TO LOWER TO MIDDLE 80S BY MID-AFTERNOON UNDER PARTLY TO MOSTLY SUNNY SKIES. THOSE PERSONS HEADED TO THE BEACHES THIS AFTERNOON ALONG THE FLORIDA BIG BEND AND EASTERN PANHANDLE SHOULD BE AWARE THAT A MODERATE RISK OF RIP CURRENTS EXIST FROM LATE THIS MORNING INTO THE AFTERNOON HOURS. WITH THE DEVELOPMENT OF THE SEABREEZE...BOTH WIND AND WAVE CONDITIONS WILL SUPPORT STRONGER AND MORE FREQUENT RIP CURRENTS. && .AVIATION... MOST SIGNIFICANT FOG PROBLEM IS AT VLD WITH 100-FT CIGS. THIS SHOULD BURN OFF BY 1330Z. VFR CONDITIONS WILL AGAIN PREVAIL ACROSS THE REGION THIS AFTERNOON WITH MAINLY FAIR WEATHER CUMULUS DEVELOPING WITH BASES IN THE 4000 TO 6000-FT RANGE LASTING UNTIL 00Z. A SEA BREEZE WILL KICK IN ONCE AGAIN AT PFN AROUND 18-19Z AND LAST FOR A FEW HOURS. ON SUNDAY MORNING...EXPECT PATCHY MORNING FOG AGAIN...MAINLY 2-3 MILES...EXCEPT AT VLD WHERE VLIFR CIGS AND VSBYS ARE PREDICTED. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 85 52 86 56 84/ 0 0 0 0 10 PANAMA CITY 80 60 84 61 82/ 0 0 0 0 10 DOTHAN 84 56 86 59 82/ 0 0 0 0 10 ALBANY 85 55 87 58 83/ 0 0 0 0 10 VALDOSTA 85 54 86 57 83/ 0 0 0 0 10 CROSS CITY 85 52 86 57 83/ 0 0 0 0 10 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...RED FLAG WARNING IN EFFECT THIS AFTERNOON THROUGH EVENING FOR ALL BUT FRANKLIN AND THE IMMEDIATE COAST OF THE REMAINING FLORIDA COASTAL ZONES. FIRE WEATHER WATCH FROM SUNDAY AFTERNOON THROUGH SUNDAY EVENING FOR ALL BUT FRANKLIN AND THE IMMEDIATE COAST OF THE REMAINING FLORIDA COASTAL ZONES. MODERATE RISK OF RIP CURRENTS ALONG BOTH BIG BEND AND EASTERN PANHANDLE BEACHES LATE THIS MORNING AND AFTERNOON. GM...NONE. && $$ MROCZKA/WATSON fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1055 AM CDT SAT MAR 24 2007 .DISCUSSION... UPDATED THE FORECAST TODAY TO INCREASE SHOWER AND THUNDERSTORM CHANCES TO 80% OVER MCLEAN COUNTY TOO. LOOKS LIKE ANOTHER BUSY DAY ESPECIALLY FROM FULTON...TAZEWELL AND MCLEAN COUNTIES NORTH WHERE FLASH FLOOD WATCH IN EFFECT UNTIL 1 AM CDT TONIGHT. THUNDERSTORMS WITH LOCALLY HEAVY RAINS ALREADY MOVING EAST INTO NORTHERN FULTON COUNTY AND EXTENDING NW INTO IOWA. ISSUED URBAN AND SMALL STREAM FLOOD ADVISORY UNTIL 130 PM FOR NORTHERN FULTON AND SOUTHERN PEORIA COUNTY AND THIS AREA MAY BE UPGRADED TO A FLOOD WARNING IF THUNDERSTORMS TRAIN. MILD HIGHS AROUND 70F NORTH AND MID TO UPPER 70S SE IL WHERE PARTLY SUNNY SKIES AND JUST 30% CHANCE OF A SHOWER OR THUNDERSTORM FROM I-70 SOUTH. 15Z/10 AM SURFACE MAP SHOWS A WARM FRONT OVER NORTHERN IN/IL INTO SOUTHERN IOWA...NUDGING JUST NORTH OF I-80. THIS WARM FRONT EXTENDS WEST TO A 1012 MB LOW PRESSURE NEAR THE CO/NE/KS BORDER. TEMPS ALREADY IN THE MID 60S WITH DANVILLE UP TO 70F WHILE MOIST DEWPOINTS IN THE UPPER 50S TO LOWER 60S LIKE YESTERDAY. ALOFT A 563 DM 500 MB CUTOFF LOW WAS NEAWR THE EASTERN CO/NM BORDER WHILE 589 DM 500 MB HIGH PRESSURE RIDGE WAS ACROSS THE GULF OF MEXICO. WATER VAPOR LOOP CONTINUES TO SHOW A TROPICAL PLUM OF MOISTURE FLOWING FROM MEXICO AND SOUTH PACIFIC UP INTO THE MIDWEST. THIS TO KEEP HEAVY RAIN THREAT NORTH OF LINCOLN THIS AFTERNOON AND CONTINUE FLASH FLOOD WATCH FOR NORTHERN 8 COUNTIES UNTIL 1 AM TONIGHT. RUC AND WRF NOW KEEPING WARM FRONT IN NORTHERN IL NEAR I-80 THIS AFTERNOON WITH SOME SHORT WAVE ENERGY AND THIS WILL BE A FOCUS OF SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND EVENING. SE IL TO BE MUCH DRIER AGAIN TODAY WITH JUST A 30% CHANCE OF CONVECTION WITH PARTLY SUNNY SKIES. 12Z KILX AND KDVN SOUNDINGS SOME SOME DRYING AT MID AND UPPER LEVELS WITH A BIT STEEPER LAPSE RATES COMPARED TO YESTERDAY. BUT SPC STILL KEEPS SLIGHT RISK OF SEVERE THUNDERSTORMS OVER WESTERN IOWA INTO KS/NE. COULD BE SOME SMALL HAIL FROM PEORIA NORTH THIS AFTERNOON ALONG WITH HEAVY DOWNPOURS AND FREQUENT LIGHTNING. HIGHS TODAY RANGE FROM AROUND 70F NORTH TO MID TO UPPER 70S IN SE IL WHERE MORE SUNSHINE. SHOULD BE A DRIER DAY SUNDAY ACROSS CENTRAL IL AS WARM FRONT LIFTS FURTHER NORTH WITH MORE SUNSHINE AND HIGHS IN THE UPPER 70S/LOWER 80S. && .PREV DISCUSSION... MAIN CHALLENGE OVER THE NEXT SEVERAL DAYS WILL BE RAIN CHANCES...AS REGION REMAINS IN A MOIST W/SW UPPER FLOW PATTERN. 06Z SURFACE ANALYSIS SHOWS NEARLY STATIONARY FRONTAL BOUNDARY EXTENDING FROM CENTRAL IOWA INTO NORTHERN ILLINOIS. UNSEASONABLY WARM AND MOIST AIRMASS IN PLACE SOUTH OF THE FRONT ACROSS CENTRAL ILLINOIS...WITH CURRENT TEMPS STILL IN THE LOWER 60S. FURTHER WEST...QUITE A BIT OF CONVECTION HAS DEVELOPED FROM KANSAS SOUTHWARD INTO WEST TEXAS...IN ASSOCIATION WITH UPPER LOW OVER THE DESERT SOUTHWEST AND 40 TO 50KT LOW-LEVEL JET. && .SHORT TERM...TODAY THROUGH MONDAY... SHORT-WAVE TROUGH CURRENTLY EVIDENT ON WATER VAPOR IMAGERY ACROSS THE DAKOTAS WILL SWING INTO THE GREAT LAKES THIS MORNING...PROVIDING A SLIGHT SOUTHWARD PUSH TO THE FRONT ACROSS NORTHERN ILLINOIS. BOTH NAM-WRF AND GFS DROP BOUNDARY INTO THE NORTHERN KILX CWA...THUS PROVIDING THE NECESSARY SYNOPTIC LIFT FOR SCATTERED SHOWERS/STORMS. CURRENT CLUSTER OF STORMS ACROSS NE KANSAS WILL TRACK NORTHEAST AND MAY CLIP THE NW CWA THIS MORNING AS WELL. BOTTOM LINE WILL BE HIGHEST POPS ACROSS THE CENTRAL AND NORTHERN ZONES...WITH MUCH LOWER POPS FURTHER SOUTH AWAY FROM THE BOUNDARY. WILL GO WITH CATEGORICAL POPS ALONG AND NW OF THE ILLINOIS RIVER...TAPERING TO LIKELY ALONG THE I-72 CORRIDOR...THEN DOWN TO CHANCE POPS ACROSS THE SE. WILL CONTINUE THE FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR LOCATIONS ALONG AND NORTH OF A CANTON TO BLOOMINGTON LINE. NOT ALL THAT IMPRESSED WITH EXPECTED QPF AMOUNTS ACROSS THAT AREA TODAY AND TONIGHT...HOWEVER DUE TO RECENT HEAVY RAINFALL...ANY ADDITIONAL RAIN WILL ONLY AGGRAVATE THE FLOODING POTENTIAL. DESPITE THE CLOUD COVER AND RAIN CHANCES...TEMPS WILL GET OFF TO A VERY WARM START TODAY...WITH AFTERNOON HIGHS RANGING FROM THE UPPER 60S FAR NORTH...TO THE UPPER 70S SOUTH OF I-70. ONCE WAVE PUSHES FURTHER EAST...FRONT WILL ONCE AGAIN START LIFTING BACK NORTHWARD TONIGHT. AS A RESULT...BEST RAIN CHANCES WILL SHIFT INTO NORTHERN ILLINOIS. HAVE TRIMMED POPS ACCORDINGLY...WITH HIGHEST POPS ACROSS THE FAR NORTH...AND LITTLE OR NO CHANCE FOR RAIN ACROSS THE SE. MODELS IN GOOD AGREEMENT ON SUNDAY...WITH BOUNDARY LIFTING EVEN FURTHER NORTH. AS A RESULT...CENTRAL ILLINOIS WILL BE FIRMLY IN THE WARM SECTOR AND SHOULD BE LARGELY CAPPED AT MID-LEVELS. HAVE THEREFORE DROPPED POPS...EXCEPT ACROSS THE FAR NW. LOW-LEVEL RH PROFILES DRY OUT CONSIDERABLY...SUGGESTING AT LEAST PARTIAL SUNSHINE ON SUNDAY. THIS WILL ALLOW TEMPS TO CLIMB TO NEAR RECORD LEVELS IN MANY LOCATIONS...WITH HIGHS GENERALLY RISING INTO THE MIDDLE TO UPPER 70S. WILL LIKELY SEE A FEW SPOTS TOP THE 80 DEGREE MARK...ESPECIALLY ACROSS THE SE. MEANWHILE...A PIECE OF ENERGY FROM THE DESERT SW UPPER LOW WILL EJECT NORTHEASTWARD INTO THE UPPER MIDWEST...TRIGGERING THUNDERSTORMS ALONG THE BOUNDARY ACROSS PARTS OF WISCONSIN. AS THIS ENERGY CONTINUES E/NE...IT WILL HELP PULL THE FRONT BACK SOUTHWARD SUNDAY NIGHT INTO MONDAY. AS A RESULT...RAIN CHANCES WILL ONCE AGAIN INCREASE FROM WEST TO EAST ACROSS THE REGION. .LONG TERM...TUESDAY THROUGH FRIDAY... WILL CONTINUE TO SEE A BROAD W/SW UPPER FLOW THROUGH THE EXTENDED...WITH MEDIUM RANGE MODELS EXHIBITING SLIGHT TIMING DIFFERENCES WITH WAVES RIDING UP BACK SIDE OF MEAN EASTERN CONUS RIDGE. END RESULT WILL BE A PROLONGED PERIOD OF VERY WARM AND UNSETTLED WEATHER. GIVEN MODEL DIFFERENCES...DID NOT MAKE MANY CHANGES TO THE EXTENDED AT THIS TIME. && .ILX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR ILZ027>031-036>038. && $$ HUETTL/BARNES il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 1050 AM EDT SAT MAR 24 2007 .MORNING UPDATE... WILL DO MINOR TWEAKS TO TEMPS AND CLOUD TRENDS TODAY...OTHERWISE THE CURRENT FCST LOOKS GOOD. VERY WARM TEMPS BUT NOT RECORD HIGHS TODAY. --21 .AVIATION (12Z TAFS)... VFR CONDITIONS EXPECTED AT ALL TAF SITES THROUGH THE TAF PERIOD. SCT-BKN MID-LEVEL DECK SEEN ACROSS SRN IN AND CNTRL KY EARLY THIS MORNING. MUCH OF THIS CLOUD COVER SHOULD MOVE OFF TO THE NORTH AND EAST THIS MORNING AS UPPER-LEVEL RIDGING PUSHES NORTHWARD OVER THE REGION FROM THE GULF. WILL TREND FROM BKN TO SCT AT SDF AND LEX FROM 12Z TO AT LEAST 18Z. ONLY EXPECTING FEW MID-LEVEL CLOUDS AT BWG. AS BKN DECK MOVES OUT OF THE AREA...SHOULD SEE A GENERAL SCT CIRRUS OR MID-LEVEL DECK ACROSS THE REGION. WINDS WILL VEER AROUND TO THE WSW BY LATE MORNING...WITH AS HIGH AS 13-15 KTS SEEN AT LEX. WEAK BOUNDARY WILL SAG SOUTHWARD THIS EVENING...AND WILL HAVE BKN MID-LEVEL DECK AT LEX AFTER 21Z...AND POSSIBLY AT SDF AS WELL. STEEP LOW-LEVEL LAPSE RATES IN PROGGED SOUNDINGS SHOW POTENTIAL FOR -SHRA. GIVEN EXPECTED LACK OF COVERAGE THOUGH...DO NOT THINK SHRA IS WARRANTED AT THIS TIME. MAY INSERT VCSH INTO LEX TAF SITE (MAYBE SDF TOO). MAY ALSO HAVE SOME HIGH END MVFR VIS`S AT LEX OR SDF TOWARD THE END OF THE TAF PERIOD...ASSUMING ANY PRECIPITATION OCCURS NEAR THE TAF SITES. AL .SHORT TERM (TODAY AND TONIGHT)... OVER THE PAST FEW DAYS...SHORT-RANGE MODELS HAVE BEEN PROGRESSIVELY DIMINISHING OUR PRECIP CHANCES FOR TODAY. RUC13 INITIALIZED WELL WITH RAINFALL AND SFC TEMPS...SO FOLLOWED CLOSE TO THIS FOR POPS AND HIGH TEMPS. CURRENTLY...SFC WARM FRONTAL BOUNDARY IS LOCATED TO OUR NORTH FROM ROUGHLY COLUMBUS OH TO DES MOINES IA. STRONG 500MB RIDGE IS LOCATED ACROSS THE GULF...WITH SFC HIGH PRESSURE DOMINATING THE SERN CONUS. WEAKENING SHORTWAVE MOVING ALONG THE OHIO RIVER IS STILL GENERATING SHOWERS ACROSS OUR INDIANA COUNTIES AS IT MOVES NE AROUND THE RIDGE. THESE SHOWERS WILL CONTINUE TO MOVE NE OUT OF THE CWA...BUT WILL LIKELY CONTINUE ACROSS OUR FAR NERN CWA UNTIL ABOUT SUNRISE. THINK I WILL LEAVE OUT POPS FROM THE GRIDS AND WILL HANDLE RESIDUAL SHOWERS WITH NOWCASTS. SHORT-RANGE MODELS MOVE THE 585DM LINE NORTHWARD ACROSS THE CWA TODAY...WHICH SHOULD SUPPRESS ANY CONVECTION. THUS WILL REMOVE POPS FROM THE GRIDS TODAY THROUGH THE AFTERNOON HOURS. AND BECAUSE OF THIS...WILL INCREASE TEMPS A TAD...TOWARD RUC13 VALUES OF LOW 80S SOUTH TO UPPER 70S NORTH (SIMILAR TO A BLEND OF RAW GFS AND MET GUIDANCE VALUES). THE FRONT TO OUR NORTH IS PROGGED TO SAG A BIT SOUTHWARD TONIGHT...AND ORIENT ITSELF FROM NW TO SE...VERY CLOSE TO OUR NERN CWA BORDER. MOS POPS AT LEX RANGE FROM 20-50 PERCENT. REALLY THINK ANY ACTIVITY WOULD BE TO OUR NE...BUT WITH THE BOUNDARY SO CLOSE WILL INSERT A SLT CHC POP ACROSS THE FAR NERN CWA...MAINLY NE OF A SALEM IN TO WINCHESTER KY LINE AFTER 21Z. WILL END SHORTLY AFTER MIDNIGHT WITH THE LOSS OF HEATING. WENT SLIGHTLY BELOW RUC TEMPS FOR OVERNIGHT LOWS...WITH UPPER 50S NNE...TO MID-TO-LOW 50S DOWN SOUTH WHERE CLOUDS WILL BE LESS. AL .LONG TERM (SUNDAY THROUGH FRIDAY)... SUNDAY THROUGH MONDAY NIGHT... ANOMALOUS RIDGING MORE TYPICAL OF LATE MAY WILL BE CENTERED ACROSS THE LOWER OHIO VALLEY SUNDAY AND MONDAY. 500MB HEIGHTS WILL AVERAGE OVER 5820M ACROSS OUR CWA...WHICH IS AROUND 2.5 STANDARD DEVIATIONS ABOVE NORMAL FOR LATE MARCH. AFTERNOON TEMPERATURES...WHILE NOT SETTING RECORD HIGHS...WILL APPROACH THEM. IF AMPLE SUN IS AVAILABLE SUNDAY AND MONDAY...HIGHS IN THE LOWER 80S ARE LIKELY. THIS RIDGING WILL CORRESPOND TO TROUGHING OUT WEST. ON SUNDAY...ONE UPPER DISTURBANCE WILL BE EJECTING NORTHEASTWARD OUT OF THE MEAN TROUGH CENTERED OVER THE ROCKIES AND WILL MOVE ACROSS THE UPPER MIDWEST. THE MAIN WESTERN TROUGH WILL HANG BACK OVER THE DESERT SOUTHWEST...AND WILL HAVE TO WAIT UNTIL EARLY TUESDAY TO MOVE EAST INTO THE SOUTHERN PLAINS. THE GFS 925MB FORECAST TEMPERATURES 17C SUNDAY AFTERNOON GIVEN GOOD INSOLATION...MONDAY MAY HAVE THE WARMEST TEMPERATURES OF ALL. WITH RIDGING EXTENDING FROM THE GULF STATES ALL THE WAY TO THE GREAT LAKES...FEEL THAT BOTH SUNDAY AND MONDAY WILL BE DRY. FORECAST SOUNDINGS SHOW NO INSTABILITY SUNDAY WITH SOMEWHAT MORE UNSTABLE CONDITIONS MONDAY. HOWEVER...WITH NO NOTICEABLE TRIGGER MONDAY...WILL REMOVE POPS. TUESDAY THROUGH WEDNESDAY... A POWERFUL AND DEEP TROUGH MOVING ONTO THE WEST COAST LATE MONDAY WILL SERVE TO KICK OUT THE AFOREMENTIONED UPPER LOW ACROSS THE SOUTHERN ROCKIES INTO THE PLAINS ON TUESDAY. THIS OPEN TROUGH SHOULD WEAKEN AS IT IMPINGES UPON THE STRONG RIDGE ACROSS THE SOUTHEASTERN STATES...AND IS FORECAST TO CROSS OKLAHOMA BY BOTH THE NAM AND THE GFS TUESDAY. DEEP SOUTHERLY FLOW AND PRECIPITABLE WATER WILL INCREASE TUESDAY AND WEDNESDAY ACROSS THE LOWER OHIO VALLEY AHEAD OF THIS TROUGH AND WILL CONTINUE CHANCE WORDING FOR POPS TUESDAY AND ADD CHANCE POPS WEDNESDAY. EXPECT WELL ABOVE NORMAL TEMPERATURES TO CONTINUE THROUGH AT LEAST THURSDAY...ALTHOUGH SLIGHTLY REDUCED TUESDAY AND WEDNESDAY DUE TO ADDITIONAL CLOUD COVER. THURSDAY AND FRIDAY... TROUGHING WILL BECOME WELL ESTABLISHED ACROSS THE ROCKIES AS STRONG LOW PRESSURE MOVES NORTH ACROSS THE CENTRAL PLAINS THURSDAY. A COLD FRONT IS EXPECTED TO MOVE EAST ACROSS THE SOUTHERN PLAINS THURSDAY AND PERHAPS ACROSS THE MISSISSIPPI RIVER FRIDAY. WITH OUR FORECAST AREA STILL UNDER RIDGING...WARM TEMPERATURES AND A CHANCE OF AFTERNOON CONVECTION WILL CONTINUE THROUGH FRIDAY. JSD && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 650 AM EDT SAT MAR 24 2007 .AVIATION (12Z TAFS)... VFR CONDITIONS EXPECTED AT ALL TAF SITES THROUGH THE TAF PERIOD. SCT-BKN MID-LEVEL DECK SEEN ACROSS SRN IN AND CNTRL KY EARLY THIS MORNING. MUCH OF THIS CLOUD COVER SHOULD MOVE OFF TO THE NORTH AND EAST THIS MORNING AS UPPER-LEVEL RIDGING PUSHES NORTHWARD OVER THE REGION FROM THE GULF. WILL TREND FROM BKN TO SCT AT SDF AND LEX FROM 12Z TO AT LEAST 18Z. ONLY EXPECTING FEW MID-LEVEL CLOUDS AT BWG. AS BKN DECK MOVES OUT OF THE AREA...SHOULD SEE A GENERAL SCT CIRRUS OR MID-LEVEL DECK ACROSS THE REGION. WINDS WILL VEER AROUND TO THE WSW BY LATE MORNING...WITH AS HIGH AS 13-15 KTS SEEN AT LEX. WEAK BOUNDARY WILL SAG SOUTHWARD THIS EVENING...AND WILL HAVE BKN MID-LEVEL DECK AT LEX AFTER 21Z...AND POSSIBLY AT SDF AS WELL. STEEP LOW-LEVEL LAPSE RATES IN PROGGED SOUNDINGS SHOW POTENTIAL FOR -SHRA. GIVEN EXPECTED LACK OF COVERAGE THOUGH...DO NOT THINK SHRA IS WARRANTED AT THIS TIME. MAY INSERT VCSH INTO LEX TAF SITE (MAYBE SDF TOO). MAY ALSO HAVE SOME HIGH END MVFR VIS`S AT LEX OR SDF TOWARD THE END OF THE TAF PERIOD...ASSUMING ANY PRECIPITATION OCCURS NEAR THE TAF SITES. AL .SHORT TERM (TODAY AND TONIGHT)... OVER THE PAST FEW DAYS...SHORT-RANGE MODELS HAVE BEEN PROGRESSIVELY DIMINISHING OUR PRECIP CHANCES FOR TODAY. RUC13 INITIALIZED WELL WITH RAINFALL AND SFC TEMPS...SO FOLLOWED CLOSE TO THIS FOR POPS AND HIGH TEMPS. CURRENTLY...SFC WARM FRONTAL BOUNDARY IS LOCATED TO OUR NORTH FROM ROUGHLY COLUMBUS OH TO DES MOINES IA. STRONG 500MB RIDGE IS LOCATED ACROSS THE GULF...WITH SFC HIGH PRESSURE DOMINATING THE SERN CONUS. WEAKENING SHORTWAVE MOVING ALONG THE OHIO RIVER IS STILL GENERATING SHOWERS ACROSS OUR INDIANA COUNTIES AS IT MOVES NE AROUND THE RIDGE. THESE SHOWERS WILL CONTINUE TO MOVE NE OUT OF THE CWA...BUT WILL LIKELY CONTINUE ACROSS OUR FAR NERN CWA UNTIL ABOUT SUNRISE. THINK I WILL LEAVE OUT POPS FROM THE GRIDS AND WILL HANDLE RESIDUAL SHOWERS WITH NOWCASTS. SHORT-RANGE MODELS MOVE THE 585DM LINE NORTHWARD ACROSS THE CWA TODAY...WHICH SHOULD SUPPRESS ANY CONVECTION. THUS WILL REMOVE POPS FROM THE GRIDS TODAY THROUGH THE AFTERNOON HOURS. AND BECAUSE OF THIS...WILL INCREASE TEMPS A TAD...TOWARD RUC13 VALUES OF LOW 80S SOUTH TO UPPER 70S NORTH (SIMILAR TO A BLEND OF RAW GFS AND MET GUIDANCE VALUES). THE FRONT TO OUR NORTH IS PROGGED TO SAG A BIT SOUTHWARD TONIGHT...AND ORIENT ITSELF FROM NW TO SE...VERY CLOSE TO OUR NERN CWA BORDER. MOS POPS AT LEX RANGE FROM 20-50 PERCENT. REALLY THINK ANY ACTIVITY WOULD BE TO OUR NE...BUT WITH THE BOUNDARY SO CLOSE WILL INSERT A SLT CHC POP ACROSS THE FAR NERN CWA...MAINLY NE OF A SALEM IN TO WINCHESTER KY LINE AFTER 21Z. WILL END SHORTLY AFTER MIDNIGHT WITH THE LOSS OF HEATING. WENT SLIGHTLY BELOW RUC TEMPS FOR OVERNIGHT LOWS...WITH UPPER 50S NNE...TO MID-TO-LOW 50S DOWN SOUTH WHERE CLOUDS WILL BE LESS. AL .LONG TERM (SUNDAY THROUGH FRIDAY)... SUNDAY THROUGH MONDAY NIGHT... ANOMALOUS RIDGING MORE TYPICAL OF LATE MAY WILL BE CENTERED ACROSS THE LOWER OHIO VALLEY SUNDAY AND MONDAY. 500MB HEIGHTS WILL AVERAGE OVER 5820M ACROSS OUR CWA...WHICH IS AROUND 2.5 STANDARD DEVIATIONS ABOVE NORMAL FOR LATE MARCH. AFTERNOON TEMPERATURES...WHILE NOT SETTING RECORD HIGHS...WILL APPROACH THEM. IF AMPLE SUN IS AVAILABLE SUNDAY AND MONDAY...HIGHS IN THE LOWER 80S ARE LIKELY. THIS RIDGING WILL CORRESPOND TO TROUGHING OUT WEST. ON SUNDAY...ONE UPPER DISTURBANCE WILL BE EJECTING NORTHEASTWARD OUT OF THE MEAN TROUGH CENTERED OVER THE ROCKIES AND WILL MOVE ACROSS THE UPPER MIDWEST. THE MAIN WESTERN TROUGH WILL HANG BACK OVER THE DESERT SOUTHWEST...AND WILL HAVE TO WAIT UNTIL EARLY TUESDAY TO MOVE EAST INTO THE SOUTHERN PLAINS. THE GFS 925MB FORECAST TEMPERATURES 17C SUNDAY AFTERNOON GIVEN GOOD INSOLATION...MONDAY MAY HAVE THE WARMEST TEMPERATURES OF ALL. WITH RIDGING EXTENDING FROM THE GULF STATES ALL THE WAY TO THE GREAT LAKES...FEEL THAT BOTH SUNDAY AND MONDAY WILL BE DRY. FORECAST SOUNDINGS SHOW NO INSTABILITY SUNDAY WITH SOMEWHAT MORE UNSTABLE CONDITIONS MONDAY. HOWEVER...WITH NO NOTICEABLE TRIGGER MONDAY...WILL REMOVE POPS. TUESDAY THROUGH WEDNESDAY... A POWERFUL AND DEEP TROUGH MOVING ONTO THE WEST COAST LATE MONDAY WILL SERVE TO KICK OUT THE AFOREMENTIONED UPPER LOW ACROSS THE SOUTHERN ROCKIES INTO THE PLAINS ON TUESDAY. THIS OPEN TROUGH SHOULD WEAKEN AS IT IMPINGES UPON THE STRONG RIDGE ACROSS THE SOUTHEASTERN STATES...AND IS FORECAST TO CROSS OKLAHOMA BY BOTH THE NAM AND THE GFS TUESDAY. DEEP SOUTHERLY FLOW AND PRECIPITABLE WATER WILL INCREASE TUESDAY AND WEDNESDAY ACROSS THE LOWER OHIO VALLEY AHEAD OF THIS TROUGH AND WILL CONTINUE CHANCE WORDING FOR POPS TUESDAY AND ADD CHANCE POPS WEDNESDAY. EXPECT WELL ABOVE NORMAL TEMPERATURES TO CONTINUE THROUGH AT LEAST THURSDAY...ALTHOUGH SLIGHTLY REDUCED TUESDAY AND WEDNESDAY DUE TO ADDITIONAL CLOUD COVER. THURSDAY AND FRIDAY... TROUGHING WILL BECOME WELL ESTABLISHED ACROSS THE ROCKIES AS STRONG LOW PRESSURE MOVES NORTH ACROSS THE CENTRAL PLAINS THURSDAY. A COLD FRONT IS EXPECTED TO MOVE EAST ACROSS THE SOUTHERN PLAINS THURSDAY AND PERHAPS ACROSS THE MISSISSIPPI RIVER FRIDAY. WITH OUR FORECAST AREA STILL UNDER RIDGING...WARM TEMPERATURES AND A CHANCE OF AFTERNOON CONVECTION WILL CONTINUE THROUGH FRIDAY. JSD && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 1027 AM EDT SAT MAR 24 2007 .UPDATE... BASED ON SAT PIX AND TRENDS...TWEAKED MAX TEMPS DWN A DEGREE OR TWO IN SOME AREAS. OTHRWISE...LEFT POPS ALONE FOR THIS AFTN FM 40 POP EXTRM NRN CNTIES TO 20 POP SRN 1/2 OF CWA. .PREV DISCUSSION... /ISSUED 702 AM EDT SAT MAR 24 2007/ UPDATE... JUST SENT QUICK UPDATE FOR LATEST CONDITIONS...DECREASED SKY CVR A LITTLE ACRS CNTRL/SCNTRL VA FOR MRNG HRS...AND TWEAKED HRLY TEMPS A BIT IN THE GRIDS. ZONE FCST HAS BEEN SENT. PREV DISCUSSION... /ISSUED 425 AM EDT SAT MAR 24 2007/ SHORT TERM/TODAY THROUGH SUNDAY...BACKDOOR COLD FRONT TO AFFECT THE REGION TODAY...LATEST SFC ANALYSIS SHOWS THE BOUNDARY LOCATED APPROXIMATELY ALONG THE RTE 460 CORRIDOR...WITH LGT NNE FLOW NORTH OF THIS AND S FLOW ACRS INLAND SRN VA AND NC ZONES. MSAS 3 HR PRESSURE CHANGES ARE WEAKENING SHOWING THAT THE HIGH TO THE NORTH IS NOT REALLY PUSHING ANY FARTHER SOUTH. WITH THIS IN MIND...HAVE A VERY LARGE TEMPERATURE GRADIENT FCST FOR HIGHS TODAY...EXPECTING LOWER 80S FROM SOUTH HILL TO BERTIE COUNTY NC...WITH A HIGH AROUND 50 AT OCEAN CITY MD. NO SINGLE GUIDANCE FWC/MAV/MET WAS FOLLOWED AS NO MODEL SEEMS TO BE ACCURATELY RESOLVING THE CURRENT CONDITIONS EARLY THIS MORNING. OVERALL HAVE GONE A LITTLE BELOW MOST GUIDANCE ACRS NE ZONES AND IMMEDIATE COASTAL LOCATIONS (SUCH AS ORF) WHERE ONSHORE NE FLOW WILL PERSIST THROUGH THE DAY...AND A LITTLE ABOVE GUIDANCE FOR INLAND SRN VA ND NC ZONES. AS FOR POPS HAVE LOWERED PRECIP CHANCES A BIT FROM PREV FCST...NOT MUCH FORCING TODAY AS MAIN SHORTWAVE ENERGY (CURRENTLY SEEN ON WV SATL OUT IN MINNESOTA) WILL TRACK WELL TO OUR NORTH ACRS PA LATER THIS AFTN. IN LOWER LVLS...THE FRONT LOOKS TO BE VERY SHALLOW AND IS WEAKENING/RETREATING BACK NORTH A LITTLE. BEST CHANCES FOR PRECIP WILL BE ACRS NORTHERN AREAS MORE MOISTURE RESIDES...BUT EVEN HERE CAPPED POPS AT 40%...ALSO ADDED DRIZZLE MENTION THIS MRNG FOR ERN SHORE/NRN NECK. FARTHER SOUTH...KEPT FCST DRY THIS MORNING. HOWEVER...BY THE AFTERNOON WITH DIFFERENTIAL HEATING BOUNDARY LIKELY TO DEVELOP DUE TO STRONG LATE MARCH SUNSHINE CANNOT RULE OUT A 20 POP FOR A SHWR EVEN IN SRN ZONES. BOTH GFS AND NAM SHOW A LITTLE BIT OF SFC BASED CAPE AND NEG LI VALUES INTO THE PIEDMONT THIS AFTN...BUT WITH VERY WEAK MID LVL LAPSE RATES (H5 TO H7) KEPT THUNDER OUT OF THE FCST FOR NOW. TONIGHT/SUNDAY...GFS/NAM BOTH SHOW RIDGING AMPLIFYING ACROSS THE MISSISSIPPI VALLEY...WITH CONFLUENCE INTO ERN GREAT LAKES. THIS SHOULD ALLOW THE FRONT TO FINALLY PUSH THROUGH THE CWA IN EARNEST BY EARLY SUNDAY MORNING. CONTINUED WITH 20 POPS SW TO 50% POPS NE TONIGHT...THEN DRY ON SUNDAY. MODEL TRNDS SHOW THE SFC HIGH TO BE A FEW MB WEAKER...SO THERE MAY STILL BE SOME RESIDUAL CLOUDINESS ON SUNDAY (HAVE GONE PTLY CLOUDY/MSTLY SUNNY FAR NE SECTIONS). HIGHS WILL AGAIN SHOW A STRONG GRADIENT BETWN WARMER SW AND COOLER NE...BUT NOT AS MUCH AS SATURDAY. LONG TERM/MONDAY THROUGH FRIDAY...FAIRLY TYPICAL SPRINGLIKE PATTERN OF CHANGEABLE CONDITIONS. OVERALL RIDGING WILL DOMINATE ALONG THE EASTERN 1/3 OF THE NATION...BUT E OF THE APPALACHIANS WE WILL BE SUBJECT TO PERIODIC BACKDOOR COLD FRONT INTRUSIONS...THE NEXT ONE LOOKING TO BE WED NIGHT OR THURSDAY. TEMPS NEAR NORMAL MON WITH WARMING TREND TUE/WED...THEN SOMEWHAT COOLER AGAIN LATE IN THE WEEK. WITH THE UNCERTAINTY THAT FAR OUT...HAVE TRENDED TEMPS DOWN A FEW DEGREES THU/FRI BUT STILL REMAINED ABOVE NEW MEX GUIDANCE VALUES. AVIATION... FNTL BNDRY HAS PUSHED INTO SRN VA THE PAST CPL OF HRS. GENLY USING 03Z RUC FOR ERY PT OF TAFS (THROUGH 15Z)...WHICH SHOWED FNT SETTLING S INTO PTS OF NE NC. WND DRCTNS TRICKY INVOF PHF/ORF/ECG/RIC AFT 15Z THROUGH 06Z/25...LEANED TWD A MR ESE SOLN...W/ SPDS AOB 10 KT. SBY SHOULD KP WNDS ENE...THEN SHIFT TO SE LT. LWR CIGS SHOULD RMN SUFFICIENTLY N OF FNTL BNDRY TDA...W/ BEST SHOT AT PDS OF MVFR/IFR AT SBY. LMTD SHRA PTNTL TO SBY ATTM. MARINE... NOT EXACTLY THE STRNGST LLVL PUSH FM THE NE THE PAST SVRL HRS W/ FNTL BNDRY SETTLING INTO SRN WTRS. WL HV ALL AREAS W/ DRCTN N OR NE TDA...WHICH SHOULD SHIFT MR E OR SE B4 THE DAY IS OVR. CONDS RMN BLO SCA THROUGH 1ST PT OF TNGT. MR SGFNT LLVL SURGE FM THE N XPCTD LT TNGT/SUN MRNG W/ EXITING S/W OFF THE CST PUSHING FNTL BNDRY S OF WTRS. XPCTG PD OF LO END SCAS VRY LT TNGT UNTIL ERY SUN AFTN (IF NOT QUITE FOR SPDS...AT LEAST FOR SEAS ON OCN) B4 CONDS SUBSIDE LT SUN/SUN NGT. WNDSHFT FM ENE TO SSW XPCTD MON INTO TUE...W/ YET ANOTHER BKDR FNT SETTLING ACRS THE WTRS MIDWEEK. TIDES... DEPARTURES RUNNING ABT 1/2 FOOT TO 1 FOOT BLO NRML THROUGH TDA...THEN GUID RAISES DEPARTURES TO NR NRML TNGT/SUN. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ GINGRICH md AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE WAKEFIELD VA 702 AM EDT SAT MAR 24 2007 .UPDATE... JUST SENT QUICK UPDATE FOR LATEST CONDITIONS...DECREASED SKY CVR A LITTLE ACRS CNTRL/SCNTRL VA FOR MRNG HRS...AND TWEAKED HRLY TEMPS A BIT IN THE GRIDS. ZONE FCST HAS BEEN SENT. && .PREV DISCUSSION... /ISSUED 425 AM EDT SAT MAR 24 2007/ SHORT TERM/TODAY THROUGH SUNDAY...BACKDOOR COLD FRONT TO AFFECT THE REGION TODAY...LATEST SFC ANALYSIS SHOWS THE BOUNDARY LOCATED APPROXIMATELY ALONG THE RTE 460 CORRIDOR...WITH LGT NNE FLOW NORTH OF THIS AND S FLOW ACRS INLAND SRN VA AND NC ZONES. MSAS 3 HR PRESSURE CHANGES ARE WEAKENING SHOWING THAT THE HIGH TO THE NORTH IS NOT REALLY PUSHING ANY FARTHER SOUTH. WITH THIS IN MIND...HAVE A VERY LARGE TEMPERATURE GRADIENT FCST FOR HIGHS TODAY...EXPECTING LOWER 80S FROM SOUTH HILL TO BERTIE COUNTY NC...WITH A HIGH AROUND 50 AT OCEAN CITY MD. NO SINGLE GUIDANCE FWC/MAV/MET WAS FOLLOWED AS NO MODEL SEEMS TO BE ACCURATELY RESOLVING THE CURRENT CONDITIONS EARLY THIS MORNING. OVERALL HAVE GONE A LITTLE BELOW MOST GUIDANCE ACRS NE ZONES AND IMMEDIATE COASTAL LOCATIONS (SUCH AS ORF) WHERE ONSHORE NE FLOW WILL PERSIST THROUGH THE DAY...AND A LITTLE ABOVE GUIDANCE FOR INLAND SRN VA ND NC ZONES. AS FOR POPS HAVE LOWERED PRECIP CHANCES A BIT FROM PREV FCST...NOT MUCH FORCING TODAY AS MAIN SHORTWAVE ENERGY (CURRENTLY SEEN ON WV SATL OUT IN MINNESOTA) WILL TRACK WELL TO OUR NORTH ACRS PA LATER THIS AFTN. IN LOWER LVLS...THE FRONT LOOKS TO BE VERY SHALLOW AND IS WEAKENING/RETREATING BACK NORTH A LITTLE. BEST CHANCES FOR PRECIP WILL BE ACRS NORTHERN AREAS MORE MOISTURE RESIDES...BUT EVEN HERE CAPPED POPS AT 40%...ALSO ADDED DRIZZLE MENTION THIS MRNG FOR ERN SHORE/NRN NECK. FARTHER SOUTH...KEPT FCST DRY THIS MORNING. HOWEVER...BY THE AFTERNOON WITH DIFFERENTIAL HEATING BOUNDARY LIKELY TO DEVELOP DUE TO STRONG LATE MARCH SUNSHINE CANNOT RULE OUT A 20 POP FOR A SHWR EVEN IN SRN ZONES. BOTH GFS AND NAM SHOW A LITTLE BIT OF SFC BASED CAPE AND NEG LI VALUES INTO THE PIEDMONT THIS AFTN...BUT WITH VERY WEAK MID LVL LAPSE RATES (H5 TO H7) KEPT THUNDER OUT OF THE FCST FOR NOW. TONIGHT/SUNDAY...GFS/NAM BOTH SHOW RIDGING AMPLIFYING ACROSS THE MISSISSIPPI VALLEY...WITH CONFLUENCE INTO ERN GREAT LAKES. THIS SHOULD ALLOW THE FRONT TO FINALLY PUSH THROUGH THE CWA IN EARNEST BY EARLY SUNDAY MORNING. CONTINUED WITH 20 POPS SW TO 50% POPS NE TONIGHT...THEN DRY ON SUNDAY. MODEL TRNDS SHOW THE SFC HIGH TO BE A FEW MB WEAKER...SO THERE MAY STILL BE SOME RESIDUAL CLOUDINESS ON SUNDAY (HAVE GONE PTLY CLOUDY/MSTLY SUNNY FAR NE SECTIONS). HIGHS WILL AGAIN SHOW A STRONG GRADIENT BETWN WARMER SW AND COOLER NE...BUT NOT AS MUCH AS SATURDAY. LONG TERM/MONDAY THROUGH FRIDAY...FAIRLY TYPICAL SPRINGLIKE PATTERN OF CHANGEABLE CONDITIONS. OVERALL RIDGING WILL DOMINATE ALONG THE EASTERN 1/3 OF THE NATION...BUT E OF THE APPALACHIANS WE WILL BE SUBJECT TO PERIODIC BACKDOOR COLD FRONT INTRUSIONS...THE NEXT ONE LOOKING TO BE WED NIGHT OR THURSDAY. TEMPS NEAR NORMAL MON WITH WARMING TREND TUE/WED...THEN SOMEWHAT COOLER AGAIN LATE IN THE WEEK. WITH THE UNCERTAINTY THAT FAR OUT...HAVE TRENDED TEMPS DOWN A FEW DEGREES THU/FRI BUT STILL REMAINED ABOVE NEW MEX GUIDANCE VALUES. AVIATION... FNTL BNDRY HAS PUSHED INTO SRN VA THE PAST CPL OF HRS. GENLY USING 03Z RUC FOR ERY PT OF TAFS (THROUGH 15Z)...WHICH SHOWED FNT SETTLING S INTO PTS OF NE NC. WND DRCTNS TRICKY INVOF PHF/ORF/ECG/RIC AFT 15Z THROUGH 06Z/25...LEANED TWD A MR ESE SOLN...W/ SPDS AOB 10 KT. SBY SHOULD KP WNDS ENE...THEN SHIFT TO SE LT. LWR CIGS SHOULD RMN SUFFICIENTLY N OF FNTL BNDRY TDA...W/ BEST SHOT AT PDS OF MVFR/IFR AT SBY. LMTD SHRA PTNTL TO SBY ATTM. MARINE... NOT EXACTLY THE STRNGST LLVL PUSH FM THE NE THE PAST SVRL HRS W/ FNTL BNDRY SETTLING INTO SRN WTRS. WL HV ALL AREAS W/ DRCTN N OR NE TDA...WHICH SHOULD SHIFT MR E OR SE B4 THE DAY IS OVR. CONDS RMN BLO SCA THROUGH 1ST PT OF TNGT. MR SGFNT LLVL SURGE FM THE N XPCTD LT TNGT/SUN MRNG W/ EXITING S/W OFF THE CST PUSHING FNTL BNDRY S OF WTRS. XPCTG PD OF LO END SCAS VRY LT TNGT UNTIL ERY SUN AFTN (IF NOT QUITE FOR SPDS...AT LEAST FOR SEAS ON OCN) B4 CONDS SUBSIDE LT SUN/SUN NGT. WNDSHFT FM ENE TO SSW XPCTD MON INTO TUE...W/ YET ANOTHER BKDR FNT SETTLING ACRS THE WTRS MIDWEEK. TIDES... DEPARTURES RUNNING ABT 1/2 FOOT TO 1 FOOT BLO NRML THROUGH TDA...THEN GUID RAISES DEPARTURES TO NR NRML TNGT/SUN. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ BROWN md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 925 AM EDT SAT MAR 24 2007 .UPDATE... LIGHT WIND FIELDS HAVE PROMOTED DEVELOPMENT OF AREAS OF DENSE FOG OVR SCNTRL UPR MI LAST NIGHT INTO EARLY THIS MORNING. 10Z TAMDAR FM KSAW INDICATED MOIST PROFILE TO NEAR 900MB WHILE YQT TAMDAR SHOWED DRIER CONDITIONS WITH MOISTURE EXTENDING TO ONLY 975MB. DRY AIR WILL SPILL IN AFTER SHORTWAVE OVR NORTH LAKE SUPERIOR PASSES THROUGH THIS MORNING. WEAK PRES RISE OVR NW WI WILL ALSO EDGE EAST AND SHOULD BEGIN TO SCOUR OUT THE FOG SO DID NOT ISSUE AN ADVY. DID UPDATE GRIDS TO EMPHASIZE FOG MORE. SECOND BATCH OF SHOWERS ALONG SHORTWAVE TROUGH DID PRODUCE SOME RAIN AT KCMX. TIMING THE BACK EDGE OF ENHANCED CLOUDS/RADAR ECHOES HAS THE SHOWERS OUT OF CWA AFTER 16Z. BASED ON MIXING TO H85 ON LATEST RUC SOUNDINGS MAY NEED TO RAISE TEMPS FM CURRENT MAX TEMPS IN GRIDS...ALTHOUGH DEVELOPING LAKE BREEZES WILL EVENTUALLY COOL THE SHORE LINES. && .PREV DISCUSSION (545 AM EDT)... WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW NEARLY ZONAL FLOW ACROSS THE NRN CONUS/SRN CANADA. IN THIS FAST FLOW...SHORTWAVE OF INTEREST IN THE SHORT TERM IS OVER SRN SASKATCHEWAN/ERN MT/WRN ND. RADARS SHOW DECENT COVERAGE OF ECHOES ACROSS ND/SRN MANITOBA ASSOCIATED WITH THIS SHORTWAVE...AND THERE HAVE BEEN A FEW OBS THAT HAVE INDICATED -SHRA IN NRN ND/SE SASKATCHEWAN/SRN MANITOBA TODAY. WELL TO THE W... SHORTWAVE THAT DROPPED OUT OF THE WESTERLIES 2-3 DAYS AGO OVER THE W COAST AND BECAME A MID LEVEL LOW IS NOW CENTERED JUST S OF AZ. THIS SYSTEM WILL BE OF INTEREST TO FCST HERE LATE IN THE UPCOMING WEEKEND AS IT GETS KICKED NE BY NEXT TROF APPROACHING THE W COAST. TODAY...WILL KEEP A SLIGHT CHC OF RAIN IN THIS MORNING FOR THE NRN TIER OF THE FCST AREA AS THE SHORTWAVE FROM NRN MN MOVES ACROSS THE FCST AREA. OTHERWISE...MODELS SHOW GOOD DRYING/SUBSIDENCE WITH MID-LVL RDGG IN THE WAKE OF SHORTWAVE SO WOULD EXPECT SKIES TO CLEAR FROM W TO E IN THE AFTERNOON. WITH WEAK SFC HIGH PRES OVER THE AREA...EXPECT LAKE BREEZE FORMATION THIS AFTERNOON NEAR LAKE SUPERIOR AND LAKE MICHIGAN TO KEEP TEMPS COOLER THERE. MIXING TO AROUND 850 MB ON FCST SOUNDINGS SHOULD YIELD HIGHS IN THE UPPER 50S TO LOWER 60S OVER THE WRN INTERIOR. TONIGHT...SFC RDG AND ASSOC VERY DRY AIRMASS IN PLACE OVER THE AREA(PWAT AOB 0.25 INCH) AND LIGHT WINDS SHOULD ALLOW FOR FAVORABLE RADIATIONAL COOLING CONDITIONS INTO THE EARLY OVERNIGHT AS TEMPS DROP INTO THE LOWER 30S PER MOS GUIDANCE. LOOK FOR INCREASING CLOUDS AFTER 06Z HOWEVER AS WINDS BECOME SE ON BACKSIDE OF RDG. HIGHER DWPNTS INTO THE LOW TO MID 30S ADVECTING OVER LAKE MICHIGAN IN A SE FLOW COULD RESULT IN PATCHY FOG FOR CENTRAL AND ERN COUNTIES AFTER MIDNIGHT. SE DOWNSLOPE WINDS LATE FOR FAR WEST COULD BRING TEMPS UP SOME BEFORE SUNRISE. SUN INTO SUN NIGHT...MDLS ARE IN GENERAL AGREEMENT LIFTING A SHRTWV...REMNANTS OF A CLOSED LOW OVER THE SW U.S...INTO THE WRN GREAT LAKES. THE 00Z UKMET IS STILL SLOWER WITH THE SYSTEM THAN THE GFS/CANADIAN AND NAM. GENERALLY FOLLOWED CONSENSUS OF GFS/NAM AND CANADIAN FOR DETAILS. INITIAL SHRA/TSRA COULD DEVELOP BY SUN MORNING OVER WI BDR COUNTIES WITH STRONG WAA AT NOSE OF 30-40 KT 850 MB JET AND PWAT VALUES INCREASING TO GREATER THAN AN INCH. 850 MB THETA-E RDG ALSO MOVES IN FROM THE W ALONG WITH DECREASING 850-500 MB THETA-E LAPSE RATES AND UPR DIFLUENCE AHEAD OF SHORTWAVE TROF. SCT STORMS FORMING IN THE SW FCST AREA IN THE MORNING WILL SPREAD NE ACROSS THE CWFA IN THE AFTERNOON. DEEP Q-VECT CONVERGENCE JUST AHEAD OF THE SHORTWAVE SPREADS ACROSS THE FCST AREA SUN NIGHT SUPPORTING LIKELY POPS ACROSS THE CWFA. ELEVATED CAPE VALUES OF 500-1000 J/KG OFF MODEL SNDGS ALONG WITH DEEP LYR SHEAR IN EXCESS OF 35 KT AND SRH APPROACHING 300 M2/S2 COULD SUPPORT SOME ELEVATED SUPERCELLS. SPC DAY 2 CONVECTIVE OUTLOOK HAS MUCH OF THE WEST AND SCNTRL FCST AREA IN A SLIGHT RISK FOR SVR STORMS. WET-BULB ZERO HEIGHTS IN 7-8 KFT RANGE WOULD ARGUE FOR LARGE HAIL AS THE BIGGEST THREAT ESPECIALLY AS LOW-LEVELS BECOME MORE STABLE BY LATE AFT AND EVENING. BRIEF HEAVY DOWNPOURS WILL BE LIKELY AS WELL BUT SINCE SYSTEM SHOULD BE FAIRLY PROGRESSIVE WOULD NOT EXPECT PCPN AMOUNTS MUCH MORE THAN HALF AN INCH. MON...EXPECT SHRA/TSRA TO END OVER THE WEST EARLY AND E BY AFTERNOON AS THE SHORTWAVE DEPARTS E AND RDGING/QVECTOR DIV BUILD IN BEHIND IT. EXPECTED SUNSHINE WITH WRLY FLOW AND 900 MB TEMPS FCST NEAR 10C SHOULD ALLOW TEMPS TO CLIMB TO LOWER 60S ESPECIALLY OVER WRN FCST AREA. LINGERING SFC TROF...POSSIBLE CLOUDS AND NW FLOW EXPECTED BEHIND THE TROF COULD KEEP ERN COUNTIES IN THE LOWER 50S. MON NIGHT INTO TUE...EXPECT DRY CONDITIONS AS MID-LVL RIDGE STAYS POSITIONED OVER THE REGION. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE...JLA PREV DISCUSSION...VOSS mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BLACKSBURG VA 1137 AM EDT SAT MAR 24 2007 .SHORT TERM /REST OF TODAY/... IN THE MOUNTAINS AND ACROSS THE FOOTHILLS AND PIEDMONT OF NORTH CAROLINA MUCH OF THE MID LEVEL CLOUDS HAVE MOVED OFF TO THE EAST. HAD SOME REPORTS OF SPRINKLES IN THE NEW RIVER VALLEY THIS MORNING. BUT NAM AND LATEST RUC CONTINUE TO BREAK UP CLOUD THIS AFTERNOON IN THE WEST. WEST WIND AND DOWNSLOPE COMPONENT...ESPECIALLY IN NORTH CAROLINA WILL BE ABLE TO MIX DOWN DRY LAYER OF AIR SEEN ON THE GSO 12Z SOUNDING. IN THE EAST THE MID AND HIGH LEVEL CLOUDS ARE SLOWING DOWN TEMPERATURE RISE. HIGHS WILL STILL BE UNSEASONABLY WARM BUT HAVE LOWERED MAXES IN ALL AREA BUT THE NORTH CAROLINA FOOTHILLS AND PIEDMONT. && .PREV DISCUSSION... /ISSUED 729 AM EDT SAT MAR 24 2007/ AVIATION /12Z-12Z/... EXPECT MID AND HIGH CLOUDS ACROSS THE FORECAST AREA TODAY AND TONIGHT. CEILINGS WILL REMAIN VFR. A BACKDOOR COLD FRONT WILL APPROACH LYH AND THE NORTHEAST COUNTIES IN THE CWA BY 12Z SUNDAY. THERE IS ONLY A SMALL CHANCE OF SHOWERS...TOO LOW TO PUT IN ANY TAF SITE. AS THE FRONT MOVES THROUGH THE SURFACE WINDS WILL BECOME NORTH TO NORTHEAST AND DRIER AIR WILL FOLLOW INTO THE FORECAST AREA. PREV DISCUSSION... /ISSUED 401 AM EDT SAT MAR 24 2007/ SHORT TERM /TODAY/... HIGH PRESSURE WAS OVER ONTARIO AND OVER THE SOUTHEAST CONUS. STATIONARY FRONT WAS IN BETWEEN...EXTENDING E-W FROM NRN VA TO CENTRAL IL. FRONT REMAINS THE FOCUS FOR CLOUDS AND PRECIP TODAY. OUR FCST AREA WILL AGAIN BE ON THE SOUTH SIDE OF THE BOUNDARY WITH CONTINUATION OF UNSEASONALLY WARM TEMPS. RECORD TMAX POSSIBLE AGAIN TODAY WITH BLF-ROA-DAN GOOD CANDIDATES FOR ESTABLISHING NEW BENCHMARKS...SEE CLIMATE SECTION BELOW FOR THE ACTUAL RECORDS. PRECIP THREAT TODAY...AGAIN MAINLY CONFINED TO AREAS ALONG AND NORTH OF I-64...CLOSER TO FRONTAL BOUNDARY. LONG TERM /TONIGHT THROUGH FRIDAY/... FRONT IS EXPECTED TO ACCELERATE SOUTHWARD ON SUNDAY...PUSHING DOWN THE EAST COAST...THE FRONT GETTING HUNG UP IN THE MTNS OF FAR WRN VA/NC. RESULT WILL BE FOCUS OF DEEPER MOISTURE OVER FAR WRN PORTIONS OF THE CWA ON SUNDAY...WITH GREATEST QPF THREAT ALONG AND WEST OF I-77. TSRA ALSO A GOOD POSSIBILITY THIS SAME CORRIDOR AS FCST GUIDANCE PROGS CAPES 500-1000 J/KG...LI`S M5...AND STEEPENING MID LEVEL LAPSE RATES ALONG THE FRONTAL BOUNDARY FROM GALAX NW THROUGH TAZEWELL AND INTO THE COAL FIELDS OF WV. THE FRONT IS EXPECTED TO CLEAR THE FCST AREA BY SUNDAY NIGHT WITH DRY STABLE LOW LEVEL AIR MOVING INTO THE ENTIRE CWA FOR MONDAY. NOT CONFIDENT ON EXACTLY HOW MUCH CLOUD COVER IF ANY WILL BE PRESENT MONDAY...BUT REGARDLESS...TEMPS SHOULD BE A COOLER BY AT LEAST 10-15 DEGREES. HIGH PRESSURE WHICH NOSES DOWN THE EAST COAST ON MONDAY IS EXPECTED TO WEAKEN AS ITS CENTER DROPS SOUTH ALONG THE CAROLINA COAST. THIS SHOULD ALLOW FOR MODERATION OF TEMPS FOR TUESDAY AND INTO MID WEEK BEFORE ANOTHER COLD FRONT...ALBEIT MUCH WEAKER THAN PREVIOUS SURGES...NOSES DOWN THRU THE NORTHEAST AND COASTAL MID ATLANTIC BEFORE DISSIPATING WED/THU. FRI/SAT WILL SEE A RETURN OF THE NE/MID ATLC THERMAL ROLLER COASTER AS AGAIN WARMER AIR SPREADS NEWD AHEAD OF THE NEXT COLD FRONT MOVING INTO THE APPLCHNS LATE FRI/SAT. AVIATION /08Z-06Z/... WEAK SURFACE FRONT OVER CENTRAL AND NORTHERN VIRGINIA WILL GRADUALLY MOVE SOUTH THROUGH THE TAF PD RESULTING IN CONSIDERABLE MID LEVEL CLOUDINESS. BEHIND THE BOUNDARY...CIGS WILL DROP TO 3000-6000 FT AGL. SHORTWAVE HELPING TO CREATE LIGHT PCPN IN ERN KY/WV MAY SPARK SOME -RA AT LWB BEFORE DAWN. MAIN SHOWER THREAT THROUGH TONIGHT WILL BE ALONG AND NORTH OF I-64...EFFECTING MAINLY LWB AND TAF SITES FARTHER NORTH. CLIMATE... RECORDS TODAY ROA 78/1994 LYH 87/1929 DAN 82/1966 BCB 78/1966 BLF 74/1988 && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SHORT TERM...AMS va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 310 PM EDT FRI MAR 23 2007 .SYNOPSIS... 18Z WATER VAPOR AND H4 RUC ANALYSIS CONTINUE TO SHOW TWO MAIN MID/UPPER LEVEL FEATURES ACROSS THE CONUS. THE FIRST AND MOST IMPORTANT TO OUR FORECAST IS THE STRONG/DOMINANT UPPER RIDGE IN CONTROL OF MUCH OF THE GULF OF MEXICO UP INTO THE SOUTHEASTERN STATES. THIS RIDGE WILL CONTINUE TO PROVIDE FAIR AND VERY WARM CONDITIONS TO THE AREA THROUGH THE WEEKEND. THE OTHER FEATURE OF NOTE IS THE DEEP TROUGH/CUTOFF LOW OVER THE SOUTHWESTERN STATES BEGINNING TO EJECT ACROSS THE WESTERN PLAINS. THIS FEATURES HAS BEEN RESPONSIBLE FOR SEVERAL ROUNDS OF STRONG TO SEVERE THUNDERSTORMS OVER THAT AREA THUS FAR AND MORE APPEARS TO BE COMING WITH THUNDERSTORMS FORECAST TO SPREAD NORTHEAST WITH THE SYSTEM THE NEXT 36 HOURS ACROSS THE CENTRAL PLAINS AND NORTHERN MISSISSIPPI VALLEY. AT THE SURFACE...HIGH PRESSURE CONTINUES TO NOSE BACK OFF THE WESTERN ATLANTIC INTO THE SOUTHEASTERN STATES. THE COMBINATION OF THE SURFACE AND UPPER LEVEL RIDGING IS PROVIDING FOR A MOSTLY SUNNY DAY ACROSS THE AREA. THE ONLY CLOUDS OF NOTE ARE A FEW HIGH LEVEL CIRRUS ADVECTING EASTWARD FROM THE WESTERN/CENTRAL GULF COAST...AND THESE WILL HAVE A DIFFICULT TIME BREAKING THROUGH THE UPPER RIDGE INTO OUR SKIES. EARLY AFTERNOON TEMPERATURES ARE ALREADY ABOVE AVERAGE WITH LOWER 80S SEEN ACROSS A GOOD PORTION OF THE CWA. .SHORT TERM (TONIGHT THROUGH TUESDAY)... UPPER RIDGE CONTINUES TO BUILD ACROSS THE EASTERN GULF AND SOUTHEASTERN STATES THROUGH THE DAYLIGHT HOURS ON MONDAY. HIGH PRESSURE BECOMES SITUATED NEARLY OVERHEAD THIS EVENING INTO THE DAY SUNDAY. THROUGH AT THIS TIME ONLY PASSING CIRRUS AND A FEW AFTERNOON CU ALONG THE SEA-BREEZE SHOULD BE EXPECTED. WITH THE STRONG RIDGING OVERHEAD (H5 HEIGHTS OF H588-590DM) AND 850MB TEMPS BETWEEN 12-14C WILL BE FORECASTING SUNDAY AFTERNOON TEMPERATURES ONCE AGAIN UP INTO THE MIDDLE 80S (PERHAPS UPPER 80S IN A FEW LOCATIONS) AFTER EARLY MORNING LOWS IN THE LOWER TO MIDDLE 50S. MUCH LIKE THIS PAST MORNING...A BIT OF PATCHY FOG IS POSSIBLE IN THE NORMALLY LOWER AND FOGGY SPOTS VERY LATE TONIGHT AND EARLY SUNDAY MORNING. AT THIS POINT WOULD EXPECT VERY LITTLE IN THE WAY OF DENSE FOG AND NO MAJOR TRAVEL PROBLEMS ARE EXPECTED AS A RESULT. A CONTINUED LIGHT GRADIENT COMBINED WITH THE STRONG INLAND HEATING WILL ONCE AGAIN RESULT IN A DECENT SEA-BREEZE CIRCULATION ALONG THE COAST DURING THE AFTERNOON HOURS WHICH SHOULD HELP KEEP TEMPERATURES IN THE UPPER 70S TO LOWER 80S AT THE BEACHES. FOR THOSE HEADING TO THE BEACHES SUNDAY AFTERNOON...THE DEVELOPING ONSHORE FLOW WILL LIKELY RESULT IN A MODERATE RIP CURRENTS RISK DURING THE AFTERNOON. A MODERATE RISK MEANS THAT WIND AND/OR WAVE CONDITIONS SUPPORT THE FORMATION OF STRONG AND MORE FREQUENT RIP CURRENTS. RE-ENFORCING SURFACE HIGH PRESSURE BEGINS TO NOSE DOWN THE EAST COAST LATER SUNDAY AND SUNDAY NIGHT. GFS/NAM SHOWING A WEAK BACK DOOR COLD FRONT SLIDING SOUTH ALONG THE COAST AHEAD OF THIS RIDGE. BOTH MODELS INDICATING A SLIGHT WIND SHIFT LATE SUNDAY NIGHT/EARLY MONDAY WITH THIS FRONTAL/TROUGH PASSAGE...BUT REALLY SHOULD BE UNEVENTFUL. ANY DYNAMICS FOR SHOWERS SHOULD BE SQUASHED BY STRONGER SUBSIDENCE UNDER THE UPPER RIDGE RESULTING IN A DRY FORECAST CONTINUING THROUGH THE REST OF THE SHORT-TERM. TEMPERATURES MONDAY...DESPITE WEAK BACK DOOR FRONT SHOULD ONCE AGAIN REACH AT LEAST THE LOWER 80S AWAY FROM THE IMMEDIATE COAST AS THE SYNOPTIC PATTERN HAS GENERALLY NOT CHANGED. STRONG RIDGE STILL IN PLACE AND 850MB TEMPS STILL AROUND 12/13C. TEMPERATURES MAY PERHAPS END UP A COUPLE OF DEGREES LOWER THAN SUNDAY AFTERNOON AS DO EXPECT A BIT MORE IN THE WAY OF HIGH CLOUDS WITH THE RIDGE AXIS PUSHING FURTHER EAST DURING THE DAY. STILL AT LEAST PARTLY SUNNY WORDING SHOULD BE FINE FOR THE AFTERNOON FORECAST. UPPER RIDGE STILL IN CONTROL OF THE FORECAST AREA FOR THE DAY ON TUESDAY...HOWEVER WILL BEGIN TO SEE SHORTWAVE ENERGY MOVING INTO THE SOUTHERN/CENTRAL MISSISSIPPI VALLEY BREAK DOWN THE WESTERN AND NORTHERN EDGES BY LATE IN THE AFTERNOON. TEMPERATURES STILL LOOKING RATHER PLEASANT WITH UPPER 70S TO PERHAPS LOWER 80S. TEMPS SHOULD BE HELD IN CHECK BY EVEN MORE IN THE WAY OF MID/HIGH CLOUDS STREAMING EAST FROM ONGOING CONVECTIONS TO OUR WEST. .LONG TERM (TUESDAY NIGHT THROUGH SATURDAY)... THE ENERGY AND MOISTURE ASSOCIATED WITH THE SHORTWAVE EXITING THE SOUTHERN PLAINS EARLY TUESDAY IS FORECAST TO LIFT TO THE NORTHEAST INTO THE TENNESSEE AND OHIO VALLEYS TUESDAY NIGHT AS DEEP LAYER RIDGING REMAINS IN PLACE OVER THE SOUTHEAST. THIS RIDGING FLATTENS OUT BY EARLY WEDNESDAY AS A WEAKENING SHORTWAVE MOVES INTO THE LOWER MISSISSIPPI VALLEY. THIS SHORTWAVE REALLY SHEARS OUT BY THE TIME IT REACHES OUR FORECAST AREA AND LITTLE TO NO SURFACE REFLECTION IS NOTED BY GUIDANCE. AT THE PRESENT TIME...THE CHANCE FOR ANY SIGNIFICANT OR EVEN MEASURABLE QPF WITH THE SHORTWAVE PASSAGE LOOK SLIM AT BEST. PERHAPS A QUICK SHOWER OR SPRINKLE EARLY WEDNESDAY...BUT THAT WOULD BE JUST ABOUT IT. LARGE SCALE RIDGING LOOKS TO RE-AMPLIFY ACROSS THE SOUTHEAST BY EARLY THURSDAY INTO FRIDAY AS HEIGHTS ONCE AGAIN FALL ACROSS THE CENTRAL AND SOUTHERN PLAINS. THIS SHORTWAVE ENERGY AND ASSOCIATED SURFACE FRONT ARE PROGGED BY THE LATEST GFS/ECMWF TO REACH OUR FORECAST AREA SOMETIME SATURDAY. HOWEVER...SIGNIFICANT QPF MAY ONCE AGAIN BE DIFFICULT TO MANAGE AS THE BEST MID/UPPER LEVEL SUPPORT IS SHOWN WELL TO OUR NORTH OVER THE TENNESSEE/OHIO VALLEYS. TEMPS SHOULD GENERALLY CONTINUE TO BE AT OR ABOVE CLIMO THROUGH THE PERIOD. && .AVIATION... BEAUTIFUL DAY ACROSS THE REGION. VFR CONDITIONS WILL PREVAIL THIS AFTERNOON WITH MAINLY FAIR WEATHER CUMULUS DEVELOPING WITH BASES IN THE 6000-FT RANGE LASTING UNTIL AROUND 00Z. A SEA BREEZE IS ALREADY ADVANCING INLAND ALONG THE COASTAL SECTIONS INCLUDING PFN. ON SUNDAY MORNING...EXPECT PATCHY MORNING FOG... MAINLY WITH VSBYS OF 2-3 MILES...EXCEPT AT VLD WHERE VLIFR CIGS AND VSBYS ARE PREDICTED. && .MARINE... SURFACE HIGH PRESSURE REMAINS NEAR OR OVER THE COASTAL WATERS THROUGH THE DAYLIGHT HOURS SUNDAY KEEPING WINDS AND SEAS GENERALLY BELOW CAUTION LEVELS. HOWEVER...WINDS MAY BECOME A BIT BREEZY AT TIMES NEAR THE COAST BOTH SUNDAY AND MONDAY AFTERNOONS WITH SEA-BREEZE DEVELOPMENT. ANOTHER RE-ENFORCING RIDGE OF HIGH PRESSURE WILL NOSE BACK ACROSS THE FORECAST WATERS FROM THE WESTERN ATLANTIC MONDAY THROUGH THURSDAY. THIS RIDGE SHOULD GENERALLY KEEP WINDS AND SEAS BELOW CAUTION LEVELS. && .FIRE WEATHER... DIFFICULT DECISION ON THE RED FLAG WARNING INTO THIS EVENING... ESPECIALLY FOR THE COASTAL COUNTIES AS AFTERNOON SEA-BREEZES HAVE DEVELOPED AND WILL KEEP AREAS NEAR THE COAST FROM ACHIEVING CRITICAL DURATIONS OF RH BELOW 35 PERCENT. MANY INLAND PORTIONS OF THE WARNING AREA ARE CURRENTLY DROPPING BELOW 35 PERCENT AND IT APPEARS LIKELY THAT DURATIONS WILL BE ACHIEVED. HAVE LEFT THE FIRE WX WATCH ALONE FOR SUNDAY AFTERNOON. AGAIN...THIS IS ANOTHER TRICKY SITUATION. CLOSE TO THE COAST SEA-BREEZE FORMATION WILL ONCE AGAIN KEEP RH FROM DROPPING BELOW 35 PERCENT FOR EXTENDED DURATIONS. CURRENT GRIDS INLAND HAVE BETWEEN 3 AND 4 HOURS OF RH NEAR OR JUST BELOW 35 PERCENT. HOWEVER...THESE VALUES ARE ACHIEVED BY GOING UNDER GUIDANCE DEWPOINTS BY SEVERAL DEGREES. WILL WAIT ONE MORE FORECAST PACKAGE AND ALLOW THE MIDNIGHT SHIFT TO MAKE A DECISION ON THE WARNING. BY MONDAY AFTERNOON RH VALUES LOOK TO REMAIN ABOVE CRITICAL THRESHOLD FOR ALL LOCATIONS. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 52 86 55 83 56 / 0 0 0 10 10 PANAMA CITY 58 84 60 81 60 / 0 0 0 10 10 DOTHAN 56 85 58 83 56 / 0 0 0 10 10 ALBANY 55 86 57 83 56 / 0 0 0 10 10 VALDOSTA 53 85 56 83 56 / 0 0 0 10 10 CROSS CITY 52 86 55 83 55 / 0 0 0 0 10 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...RED FLAG WARNING UNTIL 8 PM EDT /7 PM CDT/ THIS EVENING FOR THE FOLLOWING ZONES: BAY...CALHOUN...DIXIE...GADSDEN...GULF... HOLMES...INLAND WALTON...JACKSON...JEFFERSON...LAFAYETTE... LEON...LIBERTY...MADISON...TAYLOR...WAKULLA...WASHINGTON. FIRE WEATHER WATCH FROM SUNDAY AFTERNOON THROUGH SUNDAY EVENING FOR THE FOLLOWING ZONES: BAY...CALHOUN...DIXIE...GADSDEN... GULF...HOLMES...INLAND WALTON...JACKSON...JEFFERSON... LAFAYETTE...LEON...LIBERTY...MADISON...TAYLOR...WAKULLA... WASHINGTON. GM...NONE. && $$ AVIATION/FIREWX...WATSON PUBLIC/MARINE...MROCZKA LONG TERM...MROCZKA/BARRY fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE INDIANAPOLIS IN 330 PM EDT SAT MAR 24 2007 .SHORT TERM /TONIGHT AND SUNDAY/...A STATIONARY BOUNDARY WAS APPROXIMATELY FROM MIE TO JUST SOUTH OF LAF. THE RUC SHOWS THIS BOUNDARY DRIFTING SLIGHTLY SOUTH THEN BACK NORTH AGAIN AFTER 00Z. THE RUC/NAM ARE IN AGREEMENT AND WILL USE A BLEND. SOME TSRA HAD FORMED IN ILLINOIS AND WAS MOVING ALONG THE BOUNDARY INTO THE NORTHERN PORTION OF THE CWA. THIS IS EXPECTED TO CONTINUE MOVING EAST THROUGH THAT PORTION THROUGH THE EVENING HOURS. AFTER 00Z AS THE FRONT IS FORECAST TO START MIGRATING NORTH...MOST OF THE ACTIVITY WILL GO WITH IT. HAVE KEPT A CHANCE POP IN FOR TONIGHT THEN TAPER IT OFF TO SLIGHT CHANCE THROUGH THE MIDDLE PART OF THE CWA AND DRY SOUTH. H85/H5 RIDGING BUILDS IN TONIGHT INTO SUNDAY WHICH WILL KEEP ANY SHOWER/TSRA ACTIVITY TO A MINIMUM. THEREFORE HAVE KEPT DRY COND IN ON SUNDAY. FOR TEMPS TONIGHT...HAVE MOSTLY GONE WITH PERSISTENCE IN THE UPPER 50S. FOR SUNDAY HIGHS...WITH MOST OF THE CWA IN THE WARM SECTOR SOUTH OF THE BOUNDARY AND A GOOD SOUTH WIND WILL BUMP TEMPS UP INTO THE MID AND UPPER 70S MOST AREAS TO AROUND 80 SOUTH. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... MAIN WEATHER PROBLEM CONTINUES TO BE THE RAIN. ON SUNDAY HIGH PRESSURE BUILDS INTO INDIANA. THE MODELS ARE CONSISTANT WITH HAVING A LITTLE RAINFALL DURING THE MORNING WITH LITTLE IN THE AFTERNOON. WHILE THERE IS A LITTLE INSTABILITY THE AMOUNT OF MOISTURE DECREASES. THROUGH THE REST OF THE WEEK WEATHER SYSTEMS HAVE NOT CHANGED MUCH FROM THE SEVERAL SEVERAL DAYS. A COLD FRONT MOVES INTO INDIANA ON TUESDAY THEN BECOMES STATIONARY IN THE CENTRAL PART OF THE STATE. THIS WILL KEEP A CHANCE OF RAIN IN THE REST OF THE WORK WEEK. TEMPERATURES HAVE BEEN GOING A LITTLE HIGHER THEN GUIDANCE SO CONTINUED THAT TREND. && .AVIATION...DISCUSSION FOR 18Z TAFS AN AREA OF TSRA HAD FORMED ALONG A STATIONARY BOUNDARY JUST NORTH OF THE KLAF TAF SITE. WILL MONITOR THIS AREA FOR POSSIBLE INCLUSION IN THE 18Z KLAF TAF THIS AFTERNOON. OTHERWISE AFOREMENTIONED BOUNDARY WILL DRIFT NORTH LATER TONIGHT IN RESPONSE TO BUILDING HIGH PRESSURE OVER THE GULF STATES. AN H85/H5 RIDGE ALSO MOVES INTO THE STATE AND WILL LIKELY HINDER THUNDERSTORM DEVELOPMENT OVERNIGHT. WITH ALL TAF SITES ON THE WARM SIDE OF THE BOUNDARY ALONG WITH LIGHT WINDS AND PLENTY OF MOISTURE WOULD EXPECT SOME FOG LATE TONIGHT INTO THE MORNING HOURS. I DO NOT EXPECT SKIES TO COMPLETELY CLEAR TONIGHT SO AT THIS TIME SIGNIFICANT RADIATIONAL COOLING WILL NOT BE A BIG FACTOR AND WILL KEEP CIG/VIS IN THE MVFR CATEGORY AT ALL SITES. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. $$ SHORT TERM/AVIATION...SALLY PUBLIC...SH in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 100 PM EDT SAT MAR 24 2007 .AVIATION (18Z TAFS):... FOR THIS AFTN...SCT TO BKN AC/CS AND SCT DAYTIME CU 4-5THSD FT. LIGHT SWLY WINDS. FOR OVERNIGHT...COLD FRONT WILL MOVE SOUTHWESTWARD INTO THE NERN PTNS OF FA. SO THERE REMAINS A SMALL CHANCE FOR NIGHTTIME TRW/RW ALONG AND NE OF THE FNTL BNDRY THAT WILL LIKELY BECOME STNRY IN OR NEAR LEX...ALSO WITH LIGHT WINDS AND SOME POOLING OF DEWPOINTS NEAR FNTL BNDRY CANNOT RULE OUT SOME LATE NIGHT FOG FOR LEX BUT SDF AND BWG SHOULD REMAIN IN THE WARM AIR WI ENOUGH MIXING TO AVOID ANY LATE NIGHT FOG. --21 .MORNING UPDATE... WILL DO MINOR TWEAKS TO TEMPS AND CLOUD TRENDS TODAY...OTHERWISE THE CURRENT FCST LOOKS GOOD. VERY WARM TEMPS BUT NOT RECORD HIGHS TODAY. --21 .AVIATION (12Z TAFS)... VFR CONDITIONS EXPECTED AT ALL TAF SITES THROUGH THE TAF PERIOD. SCT-BKN MID-LEVEL DECK SEEN ACROSS SRN IN AND CNTRL KY EARLY THIS MORNING. MUCH OF THIS CLOUD COVER SHOULD MOVE OFF TO THE NORTH AND EAST THIS MORNING AS UPPER-LEVEL RIDGING PUSHES NORTHWARD OVER THE REGION FROM THE GULF. WILL TREND FROM BKN TO SCT AT SDF AND LEX FROM 12Z TO AT LEAST 18Z. ONLY EXPECTING FEW MID-LEVEL CLOUDS AT BWG. AS BKN DECK MOVES OUT OF THE AREA...SHOULD SEE A GENERAL SCT CIRRUS OR MID-LEVEL DECK ACROSS THE REGION. WINDS WILL VEER AROUND TO THE WSW BY LATE MORNING...WITH AS HIGH AS 13-15 KTS SEEN AT LEX. WEAK BOUNDARY WILL SAG SOUTHWARD THIS EVENING...AND WILL HAVE BKN MID-LEVEL DECK AT LEX AFTER 21Z...AND POSSIBLY AT SDF AS WELL. STEEP LOW-LEVEL LAPSE RATES IN PROGGED SOUNDINGS SHOW POTENTIAL FOR -SHRA. GIVEN EXPECTED LACK OF COVERAGE THOUGH...DO NOT THINK SHRA IS WARRANTED AT THIS TIME. MAY INSERT VCSH INTO LEX TAF SITE (MAYBE SDF TOO). MAY ALSO HAVE SOME HIGH END MVFR VIS`S AT LEX OR SDF TOWARD THE END OF THE TAF PERIOD...ASSUMING ANY PRECIPITATION OCCURS NEAR THE TAF SITES. AL .SHORT TERM (TODAY AND TONIGHT)... OVER THE PAST FEW DAYS...SHORT-RANGE MODELS HAVE BEEN PROGRESSIVELY DIMINISHING OUR PRECIP CHANCES FOR TODAY. RUC13 INITIALIZED WELL WITH RAINFALL AND SFC TEMPS...SO FOLLOWED CLOSE TO THIS FOR POPS AND HIGH TEMPS. CURRENTLY...SFC WARM FRONTAL BOUNDARY IS LOCATED TO OUR NORTH FROM ROUGHLY COLUMBUS OH TO DES MOINES IA. STRONG 500MB RIDGE IS LOCATED ACROSS THE GULF...WITH SFC HIGH PRESSURE DOMINATING THE SERN CONUS. WEAKENING SHORTWAVE MOVING ALONG THE OHIO RIVER IS STILL GENERATING SHOWERS ACROSS OUR INDIANA COUNTIES AS IT MOVES NE AROUND THE RIDGE. THESE SHOWERS WILL CONTINUE TO MOVE NE OUT OF THE CWA...BUT WILL LIKELY CONTINUE ACROSS OUR FAR NERN CWA UNTIL ABOUT SUNRISE. THINK I WILL LEAVE OUT POPS FROM THE GRIDS AND WILL HANDLE RESIDUAL SHOWERS WITH NOWCASTS. SHORT-RANGE MODELS MOVE THE 585DM LINE NORTHWARD ACROSS THE CWA TODAY...WHICH SHOULD SUPPRESS ANY CONVECTION. THUS WILL REMOVE POPS FROM THE GRIDS TODAY THROUGH THE AFTERNOON HOURS. AND BECAUSE OF THIS...WILL INCREASE TEMPS A TAD...TOWARD RUC13 VALUES OF LOW 80S SOUTH TO UPPER 70S NORTH (SIMILAR TO A BLEND OF RAW GFS AND MET GUIDANCE VALUES). THE FRONT TO OUR NORTH IS PROGGED TO SAG A BIT SOUTHWARD TONIGHT...AND ORIENT ITSELF FROM NW TO SE...VERY CLOSE TO OUR NERN CWA BORDER. MOS POPS AT LEX RANGE FROM 20-50 PERCENT. REALLY THINK ANY ACTIVITY WOULD BE TO OUR NE...BUT WITH THE BOUNDARY SO CLOSE WILL INSERT A SLT CHC POP ACROSS THE FAR NERN CWA...MAINLY NE OF A SALEM IN TO WINCHESTER KY LINE AFTER 21Z. WILL END SHORTLY AFTER MIDNIGHT WITH THE LOSS OF HEATING. WENT SLIGHTLY BELOW RUC TEMPS FOR OVERNIGHT LOWS...WITH UPPER 50S NNE...TO MID-TO-LOW 50S DOWN SOUTH WHERE CLOUDS WILL BE LESS. AL .LONG TERM (SUNDAY THROUGH FRIDAY)... SUNDAY THROUGH MONDAY NIGHT... ANOMALOUS RIDGING MORE TYPICAL OF LATE MAY WILL BE CENTERED ACROSS THE LOWER OHIO VALLEY SUNDAY AND MONDAY. 500MB HEIGHTS WILL AVERAGE OVER 5820M ACROSS OUR CWA...WHICH IS AROUND 2.5 STANDARD DEVIATIONS ABOVE NORMAL FOR LATE MARCH. AFTERNOON TEMPERATURES...WHILE NOT SETTING RECORD HIGHS...WILL APPROACH THEM. IF AMPLE SUN IS AVAILABLE SUNDAY AND MONDAY...HIGHS IN THE LOWER 80S ARE LIKELY. THIS RIDGING WILL CORRESPOND TO TROUGHING OUT WEST. ON SUNDAY...ONE UPPER DISTURBANCE WILL BE EJECTING NORTHEASTWARD OUT OF THE MEAN TROUGH CENTERED OVER THE ROCKIES AND WILL MOVE ACROSS THE UPPER MIDWEST. THE MAIN WESTERN TROUGH WILL HANG BACK OVER THE DESERT SOUTHWEST...AND WILL HAVE TO WAIT UNTIL EARLY TUESDAY TO MOVE EAST INTO THE SOUTHERN PLAINS. THE GFS 925MB FORECAST TEMPERATURES 17C SUNDAY AFTERNOON GIVEN GOOD INSOLATION...MONDAY MAY HAVE THE WARMEST TEMPERATURES OF ALL. WITH RIDGING EXTENDING FROM THE GULF STATES ALL THE WAY TO THE GREAT LAKES...FEEL THAT BOTH SUNDAY AND MONDAY WILL BE DRY. FORECAST SOUNDINGS SHOW NO INSTABILITY SUNDAY WITH SOMEWHAT MORE UNSTABLE CONDITIONS MONDAY. HOWEVER...WITH NO NOTICEABLE TRIGGER MONDAY...WILL REMOVE POPS. TUESDAY THROUGH WEDNESDAY... A POWERFUL AND DEEP TROUGH MOVING ONTO THE WEST COAST LATE MONDAY WILL SERVE TO KICK OUT THE AFOREMENTIONED UPPER LOW ACROSS THE SOUTHERN ROCKIES INTO THE PLAINS ON TUESDAY. THIS OPEN TROUGH SHOULD WEAKEN AS IT IMPINGES UPON THE STRONG RIDGE ACROSS THE SOUTHEASTERN STATES...AND IS FORECAST TO CROSS OKLAHOMA BY BOTH THE NAM AND THE GFS TUESDAY. DEEP SOUTHERLY FLOW AND PRECIPITABLE WATER WILL INCREASE TUESDAY AND WEDNESDAY ACROSS THE LOWER OHIO VALLEY AHEAD OF THIS TROUGH AND WILL CONTINUE CHANCE WORDING FOR POPS TUESDAY AND ADD CHANCE POPS WEDNESDAY. EXPECT WELL ABOVE NORMAL TEMPERATURES TO CONTINUE THROUGH AT LEAST THURSDAY...ALTHOUGH SLIGHTLY REDUCED TUESDAY AND WEDNESDAY DUE TO ADDITIONAL CLOUD COVER. THURSDAY AND FRIDAY... TROUGHING WILL BECOME WELL ESTABLISHED ACROSS THE ROCKIES AS STRONG LOW PRESSURE MOVES NORTH ACROSS THE CENTRAL PLAINS THURSDAY. A COLD FRONT IS EXPECTED TO MOVE EAST ACROSS THE SOUTHERN PLAINS THURSDAY AND PERHAPS ACROSS THE MISSISSIPPI RIVER FRIDAY. WITH OUR FORECAST AREA STILL UNDER RIDGING...WARM TEMPERATURES AND A CHANCE OF AFTERNOON CONVECTION WILL CONTINUE THROUGH FRIDAY. JSD && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HASTINGS NE 255 PM CDT SAT MAR 24 2007 .SHORT TERM...LATEST WATER VAPOR IMAGERY ALONG WITH PAST MORNING UPPER AIR DATA REVEALS A STRONG UPPER WAVE SPINNING SLOWLY NORTHEAST ACROSS THE CENTRAL AND SOUTHERN ROCKIES. SEVERAL SPOKES OF ENERGY ARE SEEN ROTATING AROUND THIS WAVE WITH THE MOST NOTABLE STRETCHING FROM EASTERN COLORADO INTO CENTRAL OKLAHOMA. CURRENT OBJECTIVE SURFACE ANALYSIS SHOWS A DEEP AREA OF LOW PRESSURE ACROSS NORTHEAST COLORADO WITH A LIFTING WARM FRONT SEEN EXTENDING EAST INTO CENTRAL NEBRASKA WHILE A DRYLINE IS EXTENDING SOUTH INTO WESTERN KANSAS. DECENT LOW LEVEL MOISTURE EXISTS AHEAD OF THIS DRYLINE WITH DEWPOINTS IN THE MID 50S TO LOWER 60S...ALTHOUGH LAPS AND RUC ANALYSIS DATA INDICATES ONLY WEAK INSTABILITY AT THIS POINT WITH CAPES IN THE 200 TO 600 J/KG RANGE. ACTIVE WEATHER NIGHT SHAPING UP FOR FOR THE FORECAST AREA AS THE AFOREMENTIONED UPPER WAVE SLIDES NORTHEAST FROM CENTRAL COLORADO INTO SOUTHERN SD BY SUNRISE. THIS WAVE WILL ALSO PUSH THE ASSOCIATED SURFACE LOW NORTHEAST INTO THE DAKOTAS WITH THE TRAILING DRYLINE SURGING INTO CENTRAL SECTIONS OF KANSAS AND NEBRASKA THIS EVENING. MAIN QUESTION IS THE EXTENT AND LOCATION OF CONVECTION DEVELOPING WITH THIS SYSTEM. REGIONAL RADAR MOSAIC ALREADY SHOWS AN AREA OF CONVECTION CLOSER TO THE UPPER LOW OVER EASTERN COLORADO WITH THE MODELS ALL PUSHING THIS CONVECTION NORTHEAST WITH THE UPPER SYSTEM. GIVEN THE TRACK OF THE UPPER LOW...THE BEST CHANCE OF PRECIPITATION LOOKS TO BE WEST OF A SAINT PAUL TO KEARNEY TO PHILLIPSBURG LINE. HOWEVER...A CHANCE WILL ALSO EXIST FURTHER EAST ALONG THE ADVANCING DRYLINE WITH DECENT HEIGHT FALLS ALOFT EXPECTED TO ERODE THE CAP AND BRING ISOLATED TO SCATTERED CONVECTION TO AREAS EAST OF HIGHWAY 281. ALTHOUGH THE MODELS ARE ONLY SHOWING MODEST INSTABILITY IN THE 500 TO 700 J/KG RANGE...STRONG DEEP LAYER IN EXCESS OF 50 KTS WILL SET THE STAGE FOR A FEW STORMS TO BECOME SEVERE. LOWER CAPE WILL LIMIT TORNADO POTENTIAL...ALTHOUGH A FEW BRIEF TORNADOES MAY BE POSSIBLE. THE UPPER WAVE IS THEN SHOWN TO LIFT NORTHEAST INTO THE UPPER MIDWEST SUNDAY INTO SUNDAY NIGHT WITH SUBSIDENCE SPREADING INTO THE FORECAST AREA BEHIND THIS EXITING SYSTEM. THIS WILL BRING A DRY CONDITIONS TO THE AREA SUNDAY AND SUNDAY NIGHT ALTHOUGH BREEZY SOUTHWEST WINDS WILL PREVAIL MOST OF SUNDAY. WILL AIM FOR AFTERNOON HIGHS IN THE MID 70S TO NEAR 80 FOR HIGHS. .LONG TERM...12Z MONDAY THROUGH SATURDAY. MILD TEMPERATURES LOOK TO CONTINUE THROUGH THE EXTENDED PERIOD WITH THE BEST CHANCE FOR PRECIPITATION COMING MID-WEEK. THE PERIOD STARTS OFF UNSEASONABLY WARM UNDER THE INFLUENCE OF A SOUTHWEST FLOW ALOFT AND SOUTHERLY SURFACE FLOW. H85 TEMPS CLIMB INTO THE MID TEENS AND WITH FORECAST SOUNDINGS INDICATING MIXING TO THIS LEVEL AND POSSIBLY ABOVE...MAX TEMPS SHOULD REACH THE UPPER 70S TO NEAR 80F. A SOUTHERN STREAM SHORTWAVE SLIDES THROUGH THE SOUTHWEST FLOW DURING THE AFTERNOON HOURS...BUT IT APPEARS THAT ASSOCIATED THUNDERSTORMS WITH THIS FEATURE WILL REMAIN SOUTHEAST OF THE CWA PER THE PROGGED TRACK. THUS HAVE LEFT FORECAST DRY FOR NOW AND WILL CONTINUE TO MONITOR FOR ANY NORTHERLY TREND TO SHORTWAVE TRACK. LOW-LEVEL SOUTHERLY WINDS INCREASE ON TUESDAY IN A TIGHTENING PRESSURE GRADIENT AS DEEP SURFACE LOW TRACKS ACROSS THE ROCKIES. MILD TEMPERATURES CONTINUE WITH LOW-LEVEL MOISTURE INCREASING PER PERSISTENT SOUTHERLY FLOW. THE LLJ KICKS UP TO AROUND 40 KTS TUESDAY NIGHT AHEAD OF APPROACHING SYSTEM AND RESULTANT THETA-E ADVECTION MAY TRIGGER SOME SHOWERS AND THUNDERSTORMS OVERNIGHT. THE PARENT UPPER LOW AND ATTENDANT SURFACE LOW PUSH NORTHEAST INTO THE NORTHERN PLAINS ON WEDNESDAY...DRAGGING A DRYLINE EASTWARD THROUGH THE CENTRAL PLAINS DURING THE DAY. THUNDERSTORM CHANCES WITH THIS SYSTEM REMAIN IN QUESTION WITH LATEST RUNS OF THE GFS PUSHING THE DRYLINE THROUGH THE MAJORITY OF THE CWA BY 18Z WITH A PRONOUNCED DRY SLOT OVERSPREADING THE AREA. THE ECMWF REMAINS SLOWER WITH THE PROGRESSION OF THE SYSTEM AND HAVE MAINTAINED SIMILAR POPS FROM YESTERDAY. COULD SEE SOME SEVERE ACTIVITY WITH STORMS THAT DO DEVELOP WEDNESDAY AFTERNOON/EVENING...THE MAIN QUESTION WILL BE HOW FAR EAST DRYLINE PUSHES BEFORE STORMS INITIATE. TEMPERATURES COOL BEHIND THE COLD FRONTAL PASSAGE WEDNESDAY NIGHT. MODELS DISAGREE ON AMOUNT OF COOLING FOR THURSDAY AS THE ECMWF HAS A MUCH STRONGER SECONDARY VORT LOBE THAT IT SWINGS THROUGH THE MEAN TROUGH...IN TURN PULLING COOLER AIR INTO THE REGION VERSUS THE GFS. HAVE STAYED SOMEWHERE IN BETWEEN AT THIS POINT AND A LITTLE COOLER THAN HPC GUIDANCE NUMBERS. COOLER AIR CONTINUES TO SPILL SOUTH FRIDAY AND SATURDAY ON BACKSIDE OF VERTICALLY STACKED LOW SLIDING EAST/NORTHEAST ACROSS SOUTHERN CANADA. HOWEVER...EVEN WITH THE COOL DOWN TEMPERATURES REMAIN ABOVE AVERAGE WITH HIGHS IN THE UPPER 50S TO MID 60S AND LOWS IN THE 30S TO AROUND 40. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ ne AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BLACKSBURG VA 152 PM EDT SAT MAR 24 2007 .AVIATION /18Z-18Z/... SCT-BKN STRATOCUMULUS IS FORMING FROM CENTRAL WEST VIRGINIA INTO THE NEW RIVER VALLEY. AIRMASS IS UNSTABLE CLOSER TO THE FRONTAL BOUNDARY FROM GREENBRIER COUNTY INTO CENTRAL WEST VIRGINIA AND OHIO. SCATTERED SHOWERS MAY FORM THIS AFTERNOON ALONG THIS AXIS. CEILINGS WILL REMAIN VFR. IN THE NORTHEAST CWA LOWER CLOUDS HAVE MOVED OUT AS FRONT HAS RETREATED BACK INTO NORTHERN AND CENTRAL VIRGINIA. BNDRY WILL REMAIN NEARLY STATIONARY OVERNIGHT THEN PUSH ALL THE WAY THROUGH THE FORECAST AREA ON SUNDAY. MVFR CEILINGS ARE LIKELY ALONG THE FRONT...ESPECIALLY AFTER 12Z. THE BEST CHANCE FOR ANY SHOWERS AND THUNDERSTORMS WILL BE WEST OF THE BOUNDARY...POSSIBLY AT BLF...BUT NOT UNTIL AFTER 18Z SUNDAY. && .PREV DISCUSSION... /ISSUED 1137 AM EDT SAT MAR 24 2007/ SHORT TERM /REST OF TODAY/... IN THE MOUNTAINS AND ACROSS THE FOOTHILLS AND PIEDMONT OF NORTH CAROLINA MUCH OF THE MID LEVEL CLOUDS HAVE MOVED OFF TO THE EAST. HAD SOME REPORTS OF SPRINKLES IN THE NEW RIVER VALLEY THIS MORNING. BUT NAM AND LATEST RUC CONTINUE TO BREAK UP CLOUD THIS AFTERNOON IN THE WEST. WEST WIND AND DOWNSLOPE COMPONENT...ESPECIALLY IN NORTH CAROLINA WILL BE ABLE TO MIX DOWN DRY LAYER OF AIR SEEN ON THE GSO 12Z SOUNDING. IN THE EAST THE MID AND HIGH LEVEL CLOUDS ARE SLOWING DOWN TEMPERATURE RISE. HIGHS WILL STILL BE UNSEASONABLY WARM BUT HAVE LOWERED MAXES IN ALL AREA BUT THE NORTH CAROLINA FOOTHILLS AND PIEDMONT. PREV DISCUSSION... /ISSUED 729 AM EDT SAT MAR 24 2007/ AVIATION /12Z-12Z/... EXPECT MID AND HIGH CLOUDS ACROSS THE FORECAST AREA TODAY AND TONIGHT. CEILINGS WILL REMAIN VFR. A BACKDOOR COLD FRONT WILL APPROACH LYH AND THE NORTHEAST COUNTIES IN THE CWA BY 12Z SUNDAY. THERE IS ONLY A SMALL CHANCE OF SHOWERS...TOO LOW TO PUT IN ANY TAF SITE. AS THE FRONT MOVES THROUGH THE SURFACE WINDS WILL BECOME NORTH TO NORTHEAST AND DRIER AIR WILL FOLLOW INTO THE FORECAST AREA. PREV DISCUSSION... /ISSUED 401 AM EDT SAT MAR 24 2007/ SHORT TERM /TODAY/... HIGH PRESSURE WAS OVER ONTARIO AND OVER THE SOUTHEAST CONUS. STATIONARY FRONT WAS IN BETWEEN...EXTENDING E-W FROM NRN VA TO CENTRAL IL. FRONT REMAINS THE FOCUS FOR CLOUDS AND PRECIP TODAY. OUR FCST AREA WILL AGAIN BE ON THE SOUTH SIDE OF THE BOUNDARY WITH CONTINUATION OF UNSEASONALLY WARM TEMPS. RECORD TMAX POSSIBLE AGAIN TODAY WITH BLF-ROA-DAN GOOD CANDIDATES FOR ESTABLISHING NEW BENCHMARKS...SEE CLIMATE SECTION BELOW FOR THE ACTUAL RECORDS. PRECIP THREAT TODAY...AGAIN MAINLY CONFINED TO AREAS ALONG AND NORTH OF I-64...CLOSER TO FRONTAL BOUNDARY. LONG TERM /TONIGHT THROUGH FRIDAY/... FRONT IS EXPECTED TO ACCELERATE SOUTHWARD ON SUNDAY...PUSHING DOWN THE EAST COAST...THE FRONT GETTING HUNG UP IN THE MTNS OF FAR WRN VA/NC. RESULT WILL BE FOCUS OF DEEPER MOISTURE OVER FAR WRN PORTIONS OF THE CWA ON SUNDAY...WITH GREATEST QPF THREAT ALONG AND WEST OF I-77. TSRA ALSO A GOOD POSSIBILITY THIS SAME CORRIDOR AS FCST GUIDANCE PROGS CAPES 500-1000 J/KG...LI`S M5...AND STEEPENING MID LEVEL LAPSE RATES ALONG THE FRONTAL BOUNDARY FROM GALAX NW THROUGH TAZEWELL AND INTO THE COAL FIELDS OF WV. THE FRONT IS EXPECTED TO CLEAR THE FCST AREA BY SUNDAY NIGHT WITH DRY STABLE LOW LEVEL AIR MOVING INTO THE ENTIRE CWA FOR MONDAY. NOT CONFIDENT ON EXACTLY HOW MUCH CLOUD COVER IF ANY WILL BE PRESENT MONDAY...BUT REGARDLESS...TEMPS SHOULD BE A COOLER BY AT LEAST 10-15 DEGREES. HIGH PRESSURE WHICH NOSES DOWN THE EAST COAST ON MONDAY IS EXPECTED TO WEAKEN AS ITS CENTER DROPS SOUTH ALONG THE CAROLINA COAST. THIS SHOULD ALLOW FOR MODERATION OF TEMPS FOR TUESDAY AND INTO MID WEEK BEFORE ANOTHER COLD FRONT...ALBEIT MUCH WEAKER THAN PREVIOUS SURGES...NOSES DOWN THRU THE NORTHEAST AND COASTAL MID ATLANTIC BEFORE DISSIPATING WED/THU. FRI/SAT WILL SEE A RETURN OF THE NE/MID ATLC THERMAL ROLLER COASTER AS AGAIN WARMER AIR SPREADS NEWD AHEAD OF THE NEXT COLD FRONT MOVING INTO THE APPLCHNS LATE FRI/SAT. AVIATION /08Z-06Z/... WEAK SURFACE FRONT OVER CENTRAL AND NORTHERN VIRGINIA WILL GRADUALLY MOVE SOUTH THROUGH THE TAF PD RESULTING IN CONSIDERABLE MID LEVEL CLOUDINESS. BEHIND THE BOUNDARY...CIGS WILL DROP TO 3000-6000 FT AGL. SHORTWAVE HELPING TO CREATE LIGHT PCPN IN ERN KY/WV MAY SPARK SOME -RA AT LWB BEFORE DAWN. MAIN SHOWER THREAT THROUGH TONIGHT WILL BE ALONG AND NORTH OF I-64...EFFECTING MAINLY LWB AND TAF SITES FARTHER NORTH. CLIMATE... RECORDS TODAY ROA 78/1994 LYH 87/1929 DAN 82/1966 BCB 78/1966 BLF 74/1988 && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ AVIATION...AMS va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 316 PM CDT SAT MAR 24 2007 .DISCUSSION...FORECAST FOCUS ON COMPLEX WEATHER PATTERN FOR NEXT 48 HOURS. .SHORT TERM...HAVE PULLED BACK ON TIMING OF NIGHTTIME PRECIPITATION AS NORTHWARD MOVEMENT OF FRONTAL BOUNDARY FROM EASTERN NEBRASKA TO WEST CENTRAL ILLINOIS SLOWED BY CONVECTION OVER IOWA. ALSO MIDDLE AND UPPER LEVEL RIDGING AS PER RUC PROGS CONTINUE TO HOLD BACK PRECIPITATION APPROACHING CWA FROM NORTHEAST IOWA. HOWEVER PROGS EVENTUALLY BRING FRONTAL BOUNDARY CLOSE ENOUGH TO CWA AND MIDDLE/UPPER LEVEL RIDGING BREAKS DOWN ENOUGH TO ALLOW SHORT WAVE OVER WESTERN IOWA TO GENERATE PRECIPITATION OVER CWA LATER TONIGHT. GUIDANCE AGAIN GENERATING AREAS OF DENSE FOG FOR LATE TONIGHT. THIS WILL LIKELY HAPPEN AGAIN IF APPROACHING PRECIPITATION IS DELAYED FURTHER OVERNIGHT...ESPECIALLY OVER NORTH AND EASTERN PORTIONS OF CWA. HOWEVER WILL ONLY MENTION AREAS OF FOG IN BODY OF FORECAST AS BELIEVE THE COMBINATION OF ARRIVING RAIN AND ENOUGH STIRRING OF LOW LEVEL WINDS WILL PREVENT DENSE FOG FORMATION. .LONG TERM...PROGS IN VERY GOOD AGREEMENT IN ALLOWING A FAIRLY QUIET PERIOD OF WEATHER DURING THE DAYTIME HOURS SUNDAY. RESIDUAL MORNING CONVECTION WILL RAPIDLY EXIT CWA. EXPECT SOME BREAKS IN CLOUDS WHICH WILL ALLOW MOIST AIRMASS OVER CWA TO BECOME MORE UNSTABLE WITH TIME. NOT MUCH ARGUMENT WITH SPC MODERATE/SLIGHT RISK FOR SEVERE FOR CWA WITH BEST TIMING EXPECTED IN THE MIDDLE TO LATE AFTERNOON IN THE WEST AND OVER THE ENTIRE CWA THROUGH MIDNIGHT. CRAS MODEL REFLECTS INITIAL TIMING OF CONVECTION WITH COOLING CLOUD TOPS AND SQUALL LINE DEVELOPMENT NEAR MISSISSIPPI RIVER AROUND 21Z SUNDAY. HAVE INCLUDED SEVERE AND HEAVY RAINFALL WORDING IN ZONES AS SEVERAL SEVERE WEATHER PARAMETERS FOCUS OVER CWA. AMONG PARAMETERS INCLUDES 0-1KM EHI OF 1-2, 0-6KM BULK SHEAR 50-60 KNOTS, MLCAPE OF 1200-1700 J/KG, 700-500 MB LAPSE RATES APPROACHING 7C/KM. .LONG LONG TERM...WEAK HIGH PRESSURE ALLOWS MONDAY TO BE A QUIET WEATHER DAY...BUT THEN ANOTHER WET AND UNSETTLED PERIOD OF WEATHER BEGINS LATE MONDAY NIGHT AND LASTS THROUGH FRIDAY. && .AVIATION...BRIEF BUBBLE OF HIGH PRES SCOURING OUT LOWER LEVELS A BIT THIS AFTN. HOWEVER CONCERN IS HOW EXTENSIVE FOG WILL GET TNGT. WITH BOUNDARY PROGGD TO MOVE BACK TO THE NORTH TNGT WILL INCREASE AT LEAST SOME CONFIDENCE IN MOISTURE ADVECTION FAVORABLE OF FOG FORMATION. WHAT CONCERNS ME THOUGH IS THE WIND FIELDS ARE EXPECTED TO BE A BIT SREONGER THAN LAST NIGHT AND POSSIBLE CONVECTION ASSOC WITH APPCH WRM FNT....WHICH LESSENS CONFIDENCE. HOWEVER ANALYSIS OF BUFKIT SOUNDINGS SHOWS STRONG INVERSION DEVELOPING IN THE LOWEST LEVELS WHICH LEADS TO NEAR SATURATED CONDITIONS RIGHT AT THE SURFACE. FOR NOW WILL NOT BUCK THE CONSENSUS OF THE MET/MAV/FWC MOS AND GO WITH BRINGING BACK THE VLIFR CIGS/VSBYS NEAR AND AFTER 6Z. && .MKX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ ZAJDEL/10 wi