AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 248 PM MDT FRI APR 20 2007 .SHORT TERM... (TONIGHT AND SATURDAY) CURRENTLY...DRY LINE HAS MIXED EASTWARD TO THE KANSAS BORDER...WITH DEWPOINTS FALLING INTO THE TEENS AND 20S MOST AREAS EAST OF THE MOUNTAINS. DEEP MIXING BEGINNING TO CRANK UP WIND SPEEDS MANY AREAS...WITH GUSTS OVER 30 KNOTS AT 20Z. TONIGHT...LATEST 18Z NAM AND RUC BOTH KEEP THE BOUNDARY ROUGHLY STATIONARY THIS AFTERNOON...WITH A SLIGHT WESTWARD PUSH THIS EVENING. NEITHER NAM OR GFS BREAK OUT ANY PRECIP THIS EVENING OVER THE PLAINS...BUT LATEST RUC SUGGESTS CONVECTION MAY BREAK OUT OVER SOUTHWEST KANSAS AND OKLAHOMA PANHANDLE...POSSIBLE ASSOCIATED WITH SUBTLE DRY LINE BULGE AND LOCALLY ENHANCED CONVERGENCE. COUPLE MESONET OBS SOUTH OF HIGHWAY 50 IN WESTERN KS HINT AT THIS AS WELL...WITH WINDS BACKING TO THE SOUTHEAST. WILL KEEP THE LOW POPS IN PLACE ALONG THE KANSAS BORDER TO ACCOUNT FOR CONVECTIVE POTENTIAL...THOUGH IN THE END WONDER IF ANYTHING WILL HAPPEN AS UPPER LOW MAY BE TOO FAR WEST AND CONVERGENCE TOO WEAK TO OVERCOME RATHER SUBSTANTIAL INHIBITION. FARTHER WEST...COULD SEE A FEW -SHSN BREAK OUT ALONG THE CONTINENTAL DIVIDE AFTER MIDNIGHT AS INITIAL SURGE OF MID AND HIGH LEVEL MOISTURE MOVES EAST. DOUBT WE`LL SEE MUCH PRECIP INITIALLY AS VERY DRY LOW LEVELS WILL TAKE TIME TO MOISTEN. SATURDAY...UPPER LOW EJECTS ACROSS THE STATE...WITH BROAD AREA OF UPWARD MOTION MOVING OVER SOUTHERN COLORADO. DRYLINE NEVER APPEARS TO MAKE MUCH OF PUSH WESTWARD IN THE MORNING...AND BY AFTERNOON AXIS OF DEEP INSTABILITY IS ALONG THE KS BORDER ONCE AGAIN. KEPT THE CHANCE POPS IN PLACE OVER THE FAR EAST...ALONG WITH A MENTION OF SEVERE AS 0-6KM SHEAR IS 50 PLUS KNOTS AND CAPES WELL OVER 1000 J/KG. ELSEWHERE...SUSPECT MODELS ARE OVERDONE WITH PRECIP...AS LOW LEVEL AIR MASS IS FAIRLY DRY AND STRONG S-SW DOWNSLOPE FLOW DEVELOPS OVER THE EASTERN MOUNTAINS. TRIMMED BACK POPS OVER THE EASTERN MOUNTAINS AND I-25 CORRIDOR TO LOW CHANCES...WOULDN`T BE SURPRISED IF MANY AREAS ALONG I-25 STAYED DRY. ANY CONVECTION WHICH DOES FIRE HAS THE POTENTIAL TO PRODUCE SOME VERY GUSTY WINDS DUE TO STRONG WINDS ALOFT...THOUGH FORECAST SOUNDINGS LACK THE CLASSIC INVERTED-V PROFILE DUE TO THE PRESENCE OF VARIOUS MID LEVEL MOIST LAYERS. OVERALL...FORECAST WAS IN GOOD SHAPE AND NEEDED ONLY MINOR ADJUSTMENTS. --PETERSEN .LONG TERM... (SAT NITE THROUGH THURSDAY) ...SEVERE THUNDERSTORMS POSSIBLE EARLY SAT EVENING AND ESPECIALLY MONDAY... ...A WET MONDAY NITE AND TUESDAY...(HEAVY WET SNOW FOR N EL PASO COUNTY?)... CONVECTION IS THE MAIN CONCERN THIS FCST PERIOD. STRONG SHORT WAVE CURRENTLY MOVING ONSHORE S CALIF AS I WRITE WILL BE THE WEATHER MAKER EARLY MONDAY EVENING AS THIS WILL FORCE A BROKEN LINE OF ROTATING CONVECTION TO BE IN THE VICINITY OF THE CO/KS BORDER BY OOZ SUNDAY. THE QUESTION IS NOT WILL CONVECTION FORM...BUT WHERE AND HOW FAST WILL IT MOVE. IT IS POSSIBLE THAT THE CONVECTION MAY BE OUT OF CO BY 00Z SUNDAY...BUT ITS BEST TO KEEP THE MENTION OF STORMS IN THE FORECAST...AT LEAST THROUGH EARLY SAT EVENING. ALL PARAMETERS WILL BE IN PLACE TOMORROW...INCLUDIGN SUFFICIENT SHEAR AND CAPE...SO WHEN STORMS GO UP...THEY WILL ROTATE. SPC ALREADY HAS A SLIGHT RISK ACROSS THE FAR E PLAINS WITH A STRONGLY WORDED MOD RISK (AND ASSOCIATED DAY 2 HIGH PROBABILITIES) JUST EAST OF THE AREA TOMORROW AFTERNOON AND EVENING. AFTER THIS SYSTEM GOES BY...A STRONGER SYSTEM LOOMS FOR MONDAY. AT THIS TIME...IT APPEARS ALL OF THE E CO PLAINS WILL BE UNDER THE GUN AS WIDESPREAD MODERATE TO STRONG SW FLOW ALOFT WILL OVERSPREAD STRENGTHING SE FLOW AT THE SFC. MORE THAN SUFFICIENT DEEP LAYER SHEAR WILL BE IN PLACE BY MONDAY AFTERNOON. CURRENT SIMULATIONS SHOW THAT SUFFICIENT CAPE SHOULD BE IN PLACE ALONG WITH INCREASING FORCING...SO I ANTICIPATE QUITE A FEW SUPERCELLS...SOME POTENTIALLY TORNADIC...WILL DEVELOP OVER THE REGION ON MONDAY AFTERNOON. THIS SYSTEM IS FCST TO GET WOUND UP MONDAY NIGHT AND TUESDAY AS IT MOVES SLOWLY ACROSS SE CO INTO NW KS. WRAPAROUND PRECIP WILL DEVELOP BY LATE MONDAY/EARLY TUESDAY AND IT WILL GET WET ACROSS THE E PLAINS...ESPECIALLY THE PALMER DVD. WE MAY ALSO BE DEALING WITH A SNOWSTORM ACROSS THE E FACING SLOPES OF THE S MTNS. HEAVY WET SNOW WILL ALSO BE POSSIBLE ACROSS N EL PASO COUNTY. ITS STILL TOO EARLY TO KNOW IF THIS WILL HAPPEN...BUT PATTERN RECOGNITION INDICATES IT IS A POSSIBILITY. FOR THE MTNS MONDAY AND MONDAY NIGHT...THERE WILL BE A WINDOW OF OPPURTUNITY FOR A PERIOD OF HEAVY SNOW...ESPECIALLY OVER THE SW MTNS LATE MONDAY INTO MONDAY NIGHT AS MODERATE SW FLOW ALONG WITH FAVORABEL LAPSE RATES MOVE OVER THIS REGION. BY LATE TUE THE SYSTEM SHOULD BE MOVING OUT OF THE REGION. NEXT WX SYSTEM WILL MOVE IN LATE IN THE WEEK. THIS SYSTEM SHOULD BRING IN COOLER AIR AND JUST A CHANCE OF SOME LIGHTER PRECIP. /HODANISH && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 10/34 co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DODGE CITY KS 324 PM CDT SAT APR 21 2007 .DISCUSSION... DAYS 1-2... POSSIBLE SEVERE THUNDERSTORMS WITH TORNADOES TONIGHT. 12Z UPPER AIR ANALYSIS INDICATED A 90KT JET AT H3 MOVING AROUND THE BASE OF THE UPPER TROF. AT H5, HEIGHT FALLS OF +70M WERE FOUND JUST AHEAD OF UPPER LOW AT FLAGSTAFF, AZ WITH +150M HEIGHT RISES ACROSS WEST CENTRAL CA. STRONG S/WV SWINGING ACROSS SOUTHERN AZ. ACROSS HIGH PLAINS, +8C TEMPERATURES AT H7 DOMINATED. MOISTURE POOL OF +10C AT H85 WAS STREAMING ACROSS WESTERN TX/EASTERN NM AND MOVING NORTHEAST INTO WESTERN KS. 15Z SURFACE ANALYSIS SHOWING MOISTURE POOLING ACROSS CENTRAL KS AND ALONG THE DRYLINE LOCATED IN SOUTHEAST CO SOUTHWARD INTO EASTERN NM. MAIN FORECAST CONCERN INITIALLY WILL BE START OF CONVECTION TODAY INTO TONIGHT WITH SEVERE POTENTIAL THEN CHANCE OF STRONG TO SEVERE STORMS AGAIN MONDAY. NAM/RUC INITIALIZED FAIRLY WELL WITH 12Z UPPER AIR DATA. NAM/RUC ALSO HAD GOOD HANDLE ON H85 MOISTURE THIS AM. GFS/UKMET/ECMWF WERE ALL VERY SIMILAR IN TROF POSITION BUT LACKING SOME MOISTURE PROFILE AS NAM. WILL LEAN TOWARD NAM/RUC FOR THIS FORECAST PERIOD. EXPECT TO SEE STORM INITIATION FURTHER WEST AFTER 21Z TODAY. LIS ARE ALREADY FALLING INTO THE -1C TO -5C RANGE WITH BULK OF CWA FALLING TO AT LEAST -4C BY 00Z SUN. SBCAPE ALSO INCREASES BY LATE AFTERNOON WELL OVER 1200 J/KG. MUCAPE VIA CURRENT SPC MESOANALYSIS PAGE WAS +1000J/KG WITH MID LEVEL LAPSE RATES OF 8.0C/KM. 0-1KM HELICITY IS FORECAST TO INCREASE TO +100M2/S2 WITH 0-3KM IN EXCESS OF 200M2/S2 ACROSS PORTIONS OF SOUTHWEST KANSAS BY 21Z TODAY. CURRENT DEWPOINTS ARE IN THE LOWER TO MID 50S WITH 60S ACROSS CENTRAL TX CONTINUING TO ADVECT NORTHWARD. SHOULD SEE UPPER 50S ACROSS CWA BY EVENING. AS STRONG UPPER WAVE APPROACHES FA, STORMS WILL INCREASE IN COVERAGE. BEST INSTABILITY OCCURS ACROSS PORTIONS OF SOUTHWEST KANSAS AFTER 00Z SUN. 0-1KM HELICITY VALUES ARE FORECAST TO INCREASE TO +200M2/S2, ESPECIALLY AROUND AND EAST OF A DIGHTON TO GARDEN CITY TO LIBERAL LINE. THIS WILL GRADUALLY MOVE EAST AS THE SURFACE LOW BEGINS TO PUSH EAST OF THE ROCKIES. IN ADDITION, PRECIPTABLE WATER VALUES EXCEED 1" FROM LAKIN TO ULYSSES TO HUGOTON AND EAST AFTER 00Z TONIGHT. DRIER AIR FINALLY ENTERS FA BY 06Z ACROSS THE WEST WHILE FURTHER EAST, PW VALUES REMAIN WELL ABOVE NORMAL. WITH ALL OF THE ABOVE IN MIND, IT APPEARS THAT EARLY ON, BULK OF ACTIVITY, IN THE FORM OF DISCRETE SUPERCELLS, WILL BE WEST NEAR DRYLINE/SURFACE FRONT. AS EVENING PROGRESSES INTO THE EARLY OVERNIGHT HOURS, PORTIONS OF CWA WILL BE IN FAVORABLE ENVIRONMENT FOR A FEW TORNADOES. AS THE LOW CONTINUES TO MOVE NORTHEAST, STORMS WILL EVOLVE INTO MORE OF A SQUALL LINE THREAT. LARGE HAIL, DAMAGING WINDS AND HEAVY RAINS WILL BE POSSIBLE WELL INTO THE OVERNIGHT HOURS FURTHER EAST ACROSS FA. AS SURFACE LOW PULLS NORTHEAST INTO NORTH CENTRAL KS/SOUTH CENTRAL NE BY 18Z SUN, PRECIP WILL ALSO MOVE OUT OF FA. DO NOT ANY PRECIP ACROSS WESTERN FA AFTER 06Z TONIGHT AND BULK OF PRECIP ENDING EAST BY 12Z SUN. CURRENT FORECAST HOLD ON TO SLIGHT CHANCE AFTER 12Z SUN ACROSS NORTHERN FA AND CONSIDERING EXPECTED SPEED OF SYSTEM, THIS APPEARS REASONABLE. SOME LINGERING CLOUDS ACROSS NORTHERN FA SHOULD MAKE FOR A PARTLY SUNNY DAY. SURFACE HIGH PRESSURE BUILD ACROSS FA AND H85 TEMPERATURES WILL WARM TO THE MID TEENS ACROSS THE WEST WITH COOLER READING NEAR THE DEPARTING STORM. OVERNIGHT LOWS SUNDAY WILL BE IN THE 40S AND 50S GIVEN DEWPOINTS REMAIN IN THE 40S. MONDAY WILL FEATURE THE SECOND SYSTEM IN TWO DAYS TO CREATE SEVERE CONCERN. MOISTURE WILL RETURN IN ADVANCE OF DEVELOPING CYCLONE OVER THE ROCKIES. CURRENT INDICATION ARE THAT SURFACE DEWPOINTS INTO THE LOWER 60S PORTIONS OF SOUTHWEST KANSAS IS VERY POSSIBLE. CONSIDERING MOISTURE (+60 DEWPOINTS), INSTABILITY (HIGH CAPE, LIS, HELICITY, ETC.) AND LIFT (LEADING SHORTWAVE) APPROACHES SOUTHWEST KANSAS LATE AFTERNOON/EVENING MONDAY, SEVERE THREAT IS A DEFINITE POSSIBILITY. WILL BACK OFF OF POPS STARTING AT 18Z AND START THEM INSTEAD AT 21Z MON. OTHER CHANGE PLANNED FOR THIS PERIOD IS HIGH TEMPERATURES. SHOULD SEE TEMPERATURES CLIMB A FEW DEGREES HIGHER GIVEN H85 TEMPERATURES ARE AROUND 20C WEST AND 14C EAST. IN ADDITION, THE WIND ADVISORY FOR TONIGHT HAS BEEN EXTENDED UNTIL 200 AM CDT SUNDAY MORNING. DAYS 3-7... FORECAST CHALLENGES THIS PERIOD ARE PREDICTING THE IMPACTS OF TWO MORE STRONG SYNOPTIC-SCALE STORM SYTEMS ONTO MY CWA. WEATHER-CLIMATE SITUATION REMAINS VERY COMPLEX MEANING THERE ARE INTERACTIONS INVOLVING MULTIPLE TIME AND SPACE-SCALE SIGNALS. FOR OUR PURPOSES THESE INCLUDE: 1) LOCAL SST AND EXTRATROPICALLY FORCED ENHANCED TROPICAL CONVECTION EXTENDING FROM INDONESIA INTO THE SOUTH PACIFIC, AND 2) A DYNAMICAL SIGNAL STRUGGLING TO GET BETTER ORGANIZED FROM THE EQUATORAL ATLANTIC INTO THE INDIAN OCEAN. ANOMALOUS ZONAL MEAN UPPER TROPOSPHERIC EASTERLY WIND FLOW IS INCREASING THROUGHOUT THE TROPICAL AND SUBTROPICAL ATMOSPHERES AS ANOMALOUS TWIN SUBTROPICAL ANTICYCLONES BECOME ESTABLISHED ACROSS THE EASTERN HEMISPHERE. MONITORING TOOLS INCLUDING A PHASE SPACE PLOT OF THE NORMALIZED TENDENCY OF RELATIVE ATMOSPHERIC ANGULAR MOMENTUM AND RELATIVE ATMOSPHERIC ANGULAR MOMENTUM AVAILABLE FROM ESRL/PSD INDICATE THE GLOBAL CIRCULATION REMAINS IN GSDM STAGE 4. SHOULD THE DYNAMICAL SIGNAL DISCUSSED ABOVE LEAD TO A MJO, PERHAPS AN EVOLUTION TO GSDM STAGE 1 WILL OCCUR LATER WEEK 2 OR WEEK 3. REGIONALLY, WE STILL DO HAVE UPPER TROPOSPHERIC EQUATORIAL WESTERLY WIND ANOMALIES OVER THE EAST PACIFIC. THESE WESTERLIES, INTERACTING WITH A BAROCLINIC WAVE PACKET COMING OFF OF EAST ASIA AND THE SOUTH PACIFIC CONVECTION, WILL LEAD TO ANOTHER EXTENSION OF THE NORTH PACIFIC JET BY WEEK 2. AHEAD OF ALL THIS, AND AS ALREADY SEEN ON FULL DISK SATELLITE IMAGERY, TWO MORE STORM SYSTEMS WILL IMPACT THE USA WEEK 1. WE MAY SEE SOME RESPITE FROM THIS ACTIVE REGIME WEEK 2 BEFORE MORE STORMS ON THE PLAINS AFTERWARDS. FOR THE SYSTEM MONDAY NIGHT AND TUESDAY, I PREFER THE SLOWER MODEL SOLUTIONS SUCH THE DETERMINISTIC CANADIAN AND ECMWF AS WELL AS THE ESRL/PSD ENSEMBLE. SLOW MOVING CLOSED LOWS THROUGH THE ROCKIES COMING OUT INTO THE PLAINS ARE MORE PROBABLE DURING GSDM STAGE 4. I JUST STOPPED SHORT OF GOING LIKELY POPS FOR THUNDERSTORMS. HOWEVER, TOMORROW I NOT ONLY MAY DO THAT (LATER SHIFTS MAY ALSO CONSIDER), BUT ALSO INSERT THE POSSIBILITY OF SEVERE STORMS AND HEAVY RAIN FOR THIS PERIOD. MOISTURE TRANSPORT FROM THE DEEP TROPICS WILL NOT BE AN ISSUE FOR THIS NEXT STORM. WEDNESDAY MAY BE A DAY WITH STRONG NORTH WINDS AND RAIN SHOWERS. I LEFT THE MAXES ALONE; HOWEVER, TEMPERATURES MAY NOT GET OUT OF THE 50S. THURSDAY WILL BE A BREAK WITH TEMPERATURES AT LEAST CLIMATOLOGY, FOLLOWED BY ANOTHER OPPORTUNITY FOR RAIN AND THUNDERSTORMS LATER FRIDAY INTO SATURDAY. FOR NOW I WENT WITH THE CLIMATOLOGY 30 PERCENT POPS; HOWEVER, I MAY ALSO RAISE THOSE TOMORROW. I LEFT TEMPERATURES AROUND CLIMATOLOGY FOR FRIDAY AND SATURDAY. LATER SHIFTS MAY CONSIDER RAISING MAXES AND MINS FOR AT LEAST FRIDAY. OUR WEEK 2 FORECAST (APRIL 29TH - MAY 5TH) WILL READ NEAR NORMAL FOR TEMPERATURES AND PRECIPITATION. THIS MAY BE OPTIMISTIC FOR PEOPLE WHO DO NOT WANT MORE RAINFALL AND SEVERE THUNDERSTORMS. && .AVIATION... MOISTURE TRANSPORT INTO MY CWA HAS BEEN IMPROVING ALLOWING MVFR CIGS TO PERSIST DESPITE STRONG MIXING WITH THE INCREASING SOUTH WINDS. SPECIAL 18Z SOUNDING PER SPC SHOWS OUR DEWPOINT AT 850MB TO BE 10.9C MEANING A GOOD SIGNAL FOR A DEEPENING MOIST LAYER. I MAINTAINED THE MVFR CIGS TO ABOUT 21Z. ISOLATED SUPERCELL THUNDERSTORMS SHOULD INITIATE ALONG A DRYLINE/PACIFIC COLD FRONT JUST WEST OF THE COLORADO BORDER AFTER 21Z, AND THEN EVOLVE INTO A MCS AFTER 00Z. EVEN THOUGH MOISTURE IS SOMEWHAT LIMITED, THERE WILL BE A WINDOW OF OPPORTUNITY FOR A FEW TORNADOES UNTIL THE STORMS ORGANIZE INTO A CLUSTER. THESE THUNDERSTORMS SHOULD BE IMPACTING GCK BY AROUND 00Z AND THEN INTO HYS BY ABOUT 03Z. SEVERE THUNDERSTORMS PARTICULARLY FOR DAMAGING WIND AND LARGE HAIL ARE LIKELY ESPECIALLY AROUND GCK AND DDC. && .PRELIMINARY POINT TEMPS/POPS... DDC 53 72 48 76 / 100 10 0 40 GCK 51 72 46 75 / 100 10 0 40 EHA 49 74 47 80 / 100 0 0 40 LBL 51 73 48 79 / 100 0 0 40 HYS 53 70 45 73 / 90 40 0 40 P28 57 75 52 78 / 90 10 0 40 && .DDC WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 2 AM CDT /1 AM MDT/ SUNDAY FOR KSZ030-031- 043>046-061>066-074>081-084>090. && $$ FN30/23/23 ks AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE TOPEKA KS 556 AM CDT FRI APR 20 2007 .DISCUSSION... WITH MID CLOUDS THINNING AND RADAR SHOWING ACTIVITY OFF TO THE FAR NORTH...WILL BE DOING A FORECAST UPDATE TO TAKE OUT MENTION OF PRECIPITATION CHANCES FOR THE NORTHERN AND WESTERN COUNTIES THIS MORNING. LATEST RUC STILL SHOWING SOME QPF POTENTIAL BUT IT WOULD HAVE HAD RAIN ACROSS MUCH OF THE WESTERN PORTIONS OF THE CWA THROUGH THE NIGHT. 06Z NAM HAD SOME SPOTTY QPF FOR THE AM BUT FURTHER WEST OF CWA. LATEST WATER VAPOR NOT GIVING ANY SIGNS FOR UPPER SUPPORT OVER CWA. && PF .PREVIOUS DISCUSSION... 455 AM CDT FRI APR 20 2007 SHORT TERM CONCERNS FOR TODAY ARE PRECIPITATION CHANCES THIS MORNING OVER THE NORTHERN COUNTIES...AND OVER THE FAR NORTHWEST COUNTIES THIS AFTERNOON. CONCERNS OVERNIGHT ARE AGAIN PRECIPITATION CHANCES OVER THE NORTHWEST COUNTIES. FOR THE WEEKEND...CONCERNS ARE HOW FAST THE PRECIPITATION SPREADS EASTWARD AND SEVERE POTENTIAL. BEYOND THE WEEKEND HAVE CHANCES OF PRECIPITATION AGAIN TUESDAY THROUGH THURSDAY. LATEST WATER VAPOR IMAGERY AND PROFILERS SHOWING SEVERAL LOBES OF UPPER ENERGY OVER THE WESTERN CONUS AND COMING INTO THE WEST COAST...WITH RIDGING OVER THE MID MISSISSIPPI VALLEY SLIDING SLOWLY SOUTHEAST. SURFACE PATTERN HAD LOW PRESSURE OVER THE HIGH PLAINS WITH FRONTAL BOUNDARY/DRY LINE FROM WESTERN PORTIONS OF NEBRASKA INTO SOUTHEAST COLORADO. INCREASING SOUTHERLY FLOW HAS DRAWN A CHANNEL OF 50 DEWPOINTS NORTHWARD ACROSS CENTRAL KANSAS WITH MID 50 DEWPOINTS ENTERING SOUTH CENTRAL PORTIONS OF THE STATE. SURFACE TEMPERATURES WERE IN THE LOWER TO MID 50S. IN THE CORE OF DEEPER MOISTURE AND WITH THE AID OF THE TAIL END OF SOME SHORTWAVE ENERGY ROTATING AROUND NORTHERN UPPER LOW OVER MONTANA...AND WARM ADVECTION...ISOLATED THUNDERSTORMS DEVELOP OVER PARTS OF NORTHWEST AND NORTH CENTRAL KANSAS DURING THURSDAY EVENING...MOVING TO THE NORTHEAST. ACTIVITY DIMINISHED AFTER MIDNIGHT BUT MID LEVEL CLOUD BAND LINGERS. THE EVENING RUC MODEL SHOWED SOME QPF POTENTIAL OVER THE NORTHERN COUNTIES INTO THE MORNING HOURS AND THE 00Z NAM HAD SOME SPOTTY QPF AS WELL...AND WITH THE MID CLOUDS AROUND...LEFT SOME SLIGHT CHANCE POPS NORTHCENTRAL AND FAR NORTHERN COUNTIES THIS MORNING. OTHERWISE...EXPECTING BREEZY CONDITIONS WITH HIGHS TEMPERATURES REACHING THE MID 70S MOST AREAS TODAY AND PARTLY TO MOSTLY SUNNY SKIES. WITH THE NAM SOUNDINGS SHOWING LITTLE IN THE WAY OF CAP AND IN THE VICINITY OF MOISTURE CONVERGENCE...HAVE LEFT SOME LOW CHANCE POPS OVER THE NORTH CENTRAL COUNTIES LATE THIS AFTERNOON AND CONTINUED DURING THE NIGHT TIME HOURS A COUNTY OR SO FURTHER EAST. LOWS TONIGHT IN THE MIDDLE 50S WITH WINDS AND INCREASING CLOUDS HELPING KEEP READINGS MILD. MODELS STILL SLOWING THE MOVEMENT OF THE SOUTHWEST UPPER LOW FOR THE WEEKEND WEATHER. AHEAD OF THIS FEATURE...SURFACE LOW DEEPENS OVER THE HIGH PLAINS...KEEPING IT WINDY WHILE DRAWING MOISTURE NORTH AND WESTWARD. UPPER DYNAMICS AND FOCUS FOR ACTIVITY ALONG THE DRY LINE FAVOR THE HIGH PLAINS SATURDAY AFTERNOON WITH ACTIVITY GRADUALLY MOVING EASTWARD SATURDAY NIGHT. NAM IS MUCH SLOWER IN PUSHING THE PRECIPITATION CHANCES EAST AND FOR NOW FAVORING THE BIT MORE PROGRESSIVE GFS AS SYSTEM NOW APPROACHING PACIFIC NORTHWEST ACTS AS KICKER WHEN IT DIVES SOUTH. INCREASED THE WESTERN PORTIONS OF CWA INTO THE "LIKELY" RAIN CHANCE CATEGORY SATURDAY NIGHT....THEN SPREAD THAT TO THE EAST ON SUNDAY. THUNDERSTORMS COULD BE SEVERE OVER THE WESTERN COUNTIES ESPECIALLY INTO THE EARLY NIGHTTIME HOURS SATURDAY. HIGHS SATURDAY IN THE UPPER 70S MOST AREAS...LOWS SATURDAY NIGHT AGAIN MILD...IN THE MIDDLE 50S. ON SUNDAY...UPPER WAVE EJECTS NORTHEAST ACROSS THE CWA WITH BEST PRECIPITATION CHANCES MORNING INTO MID AFTERNOON ON THE GFS...THE NAM A BIT SLOWER. AGAIN GIVEN THE SHEAR AND INSTABILITY...SOME POTENTIAL FOR SEVERE BUT WILL DEPEND ON EXTENT OF SATURDAY NIGHT CONVECTION. WITH CLOUD COVER AND PRECIPITATION...HIGHS SUNDAY IN THE LOWER TO MIDDLE 70S. HAVE COMPROMISED ON GFS/NAM MOVEMENT THUS LEFT SOME LOW CHANCE POPS FOR SUNDAY EVENING...THE GFS WOULD HAVE PRECIP EXITING THE AREA BY 00Z MON. ONLY SOME MINOR BLENDING CHANGES TO GOING FORECAST BEYOND SUNDAY NIGHT. FRONTAL BOUNDARY TO THE SOUTH GIVES SOME POTENTIAL FOR THUNDERSTORMS OVER THE SOUTHERN COUNTIES ON MONDAY. NEXT WAVE ENTERS THE AREA MONDAY AND BECOMES A SLOW MOVER IN THE SOUTHERN STREAM GIVING A PROLONGED PERIOD OF PRECIPITATION CHANCES TUESDAY INTO WEDNESDAY. HIGH TEMPERATURES MONDAY AND TUESDAY MAINLY IN THE LOWER TO MID 70S...COOLING INTO THE MID TO UPPER 60S FOR WEDNESDAY AND THURSDAY...LOWS MAINLY IN THE RANGE OF THE UPPER 40S TO LOWER 50S. && .TOP WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PF ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TOPEKA KS 455 AM CDT FRI APR 20 2007 .DISCUSSION... SHORT TERM CONCERNS FOR TODAY ARE PRECIPITATION CHANCES THIS MORNING OVER THE NORTHERN COUNTIES...AND OVER THE FAR NORTHWEST COUNTIES THIS AFTERNOON. CONCERNS OVERNIGHT ARE AGAIN PRECIPITATION CHANCES OVER THE NORTHWEST COUNTIES. FOR THE WEEKEND...CONCERNS ARE HOW FAST THE PRECIPITATION SPREADS EASTWARD AND SEVERE POTENTIAL. BEYOND THE WEEKEND HAVE CHANCES OF PRECIPITATION AGAIN TUESDAY THROUGH THURSDAY. LATEST WATER VAPOR IMAGERY AND PROFILERS SHOWING SEVERAL LOBES OF UPPER ENERGY OVER THE WESTERN CONUS AND COMING INTO THE WEST COAST...WITH RIDGING OVER THE MID MISSISSIPPI VALLEY SLIDING SLOWLY SOUTHEAST. SURFACE PATTERN HAD LOW PRESSURE OVER THE HIGH PLAINS WITH FRONTAL BOUNDARY/DRY LINE FROM WESTERN PORTIONS OF NEBRASKA INTO SOUTHEAST COLORADO. INCREASING SOUTHERLY FLOW HAS DRAWN A CHANNEL OF 50 DEWPOINTS NORTHWARD ACROSS CENTRAL KANSAS WITH MID 50 DEWPOINTS ENTERING SOUTH CENTRAL PORTIONS OF THE STATE. SURFACE TEMPERATURES WERE IN THE LOWER TO MID 50S. IN THE CORE OF DEEPER MOISTURE AND WITH THE AID OF THE TAIL END OF SOME SHORTWAVE ENERGY ROTATING AROUND NORTHERN UPPER LOW OVER MONTANA...AND WARM ADVECTION...ISOLATED THUNDERSTORMS DEVELOP OVER PARTS OF NORTHWEST AND NORTH CENTRAL KANSAS DURING THURSDAY EVENING...MOVING TO THE NORTHEAST. ACTIVITY DIMINISHED AFTER MIDNIGHT BUT MID LEVEL CLOUD BAND LINGERS. THE EVENING RUC MODEL SHOWED SOME QPF POTENTIAL OVER THE NORTHERN COUNTIES INTO THE MORNING HOURS AND THE 00Z NAM HAD SOME SPOTTY QPF AS WELL...AND WITH THE MID CLOUDS AROUND...LEFT SOME SLIGHT CHANCE POPS NORTHCENTRAL AND FAR NORTHERN COUNTIES THIS MORNING. OTHERWISE...EXPECTING BREEZY CONDITIONS WITH HIGHS TEMPERATURES REACHING THE MID 70S MOST AREAS TODAY AND PARTLY TO MOSTLY SUNNY SKIES. WITH THE NAM SOUNDINGS SHOWING LITTLE IN THE WAY OF CAP AND IN THE VICINITY OF MOISTURE CONVERGENCE...HAVE LEFT SOME LOW CHANCE POPS OVER THE NORTH CENTRAL COUNTIES LATE THIS AFTERNOON AND CONTINUED DURING THE NIGHT TIME HOURS A COUNTY OR SO FURTHER EAST. LOWS TONIGHT IN THE MIDDLE 50S WITH WINDS AND INCREASING CLOUDS HELPING KEEP READINGS MILD. MODELS STILL SLOWING THE MOVEMENT OF THE SOUTHWEST UPPER LOW FOR THE WEEKEND WEATHER. AHEAD OF THIS FEATURE...SURFACE LOW DEEPENS OVER THE HIGH PLAINS...KEEPING IT WINDY WHILE DRAWING MOISTURE NORTH AND WESTWARD. UPPER DYNAMICS AND FOCUS FOR ACTIVITY ALONG THE DRY LINE FAVOR THE HIGH PLAINS SATURDAY AFTERNOON WITH ACTIVITY GRADUALLY MOVING EASTWARD SATURDAY NIGHT. NAM IS MUCH SLOWER IN PUSHING THE PRECIPITATION CHANCES EAST AND FOR NOW FAVORING THE BIT MORE PROGRESSIVE GFS AS SYSTEM NOW APPROACHING PACIFIC NORTHWEST ACTS AS KICKER WHEN IT DIVES SOUTH. INCREASED THE WESTERN PORTIONS OF CWA INTO THE "LIKELY" RAIN CHANCE CATEGORY SATURDAY NIGHT....THEN SPREAD THAT TO THE EAST ON SUNDAY. THUNDERSTORMS COULD BE SEVERE OVER THE WESTERN COUNTIES ESPECIALLY INTO THE EARLY NIGHTTIME HOURS SATURDAY. HIGHS SATURDAY IN THE UPPER 70S MOST AREAS...LOWS SATURDAY NIGHT AGAIN MILD...IN THE MIDDLE 50S. ON SUNDAY...UPPER WAVE EJECTS NORTHEAST ACROSS THE CWA WITH BEST PRECIPITATION CHANCES MORNING INTO MID AFTERNOON ON THE GFS...THE NAM A BIT SLOWER. AGAIN GIVEN THE SHEAR AND INSTABILITY...SOME POTENTIAL FOR SEVERE BUT WILL DEPEND ON EXTENT OF SATURDAY NIGHT CONVECTION. WITH CLOUD COVER AND PRECIPITATION...HIGHS SUNDAY IN THE LOWER TO MIDDLE 70S. HAVE COMPROMISED ON GFS/NAM MOVEMENT THUS LEFT SOME LOW CHANCE POPS FOR SUNDAY EVENING...THE GFS WOULD HAVE PRECIP EXITING THE AREA BY 00Z MON. ONLY SOME MINOR BLENDING CHANGES TO GOING FORECAST BEYOND SUNDAY NIGHT. FRONTAL BOUNDARY TO THE SOUTH GIVES SOME POTENTIAL FOR THUNDERSTORMS OVER THE SOUTHERN COUNTIES ON MONDAY. NEXT WAVE ENTERS THE AREA MONDAY AND BECOMES A SLOW MOVER IN THE SOUTHERN STREAM GIVING A PROLONGED PERIOD OF PRECIPITATION CHANCES TUESDAY INTO WEDNESDAY. HIGH TEMPERATURES MONDAY AND TUESDAY MAINLY IN THE LOWER TO MID 70S...COOLING INTO THE MID TO UPPER 60S FOR WEDNESDAY AND THURSDAY...LOWS MAINLY IN THE RANGE OF THE UPPER 40S TO LOWER 50S. && .TOP WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PF ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 200 AM MDT FRI APR 20 2007 .DISCUSSION...FORECAST CONCERNS REMAIN ON SEVERE THUNDERSTORM POTENTIAL TODAY AND ESPECIALLY SATURDAY AS AN OUTBREAK IS POSSIBLE. HEAVY RAIN AND THE THREAT FOR LOCALIZED FLOODING WILL INCREASE SATURDAY NIGHT. .SHORT TERM (TODAY-SUNDAY NIGHT) TODAY/TONIGHT...SOUTHEASTERLY SFC WINDS WILL INCREASE INTO THE BREEZY TO WINDY CATEGORY THIS AFTERNOON AND INTO THE OVERNIGHT HOURS AS LOW PRESSURE DEVELOPS ALONG THE LEE SIDE OF THE ROCKIES AHEAD OF AN UPPER LEVEL LOW PRESSURE AREA WHICH BY 12Z SATURDAY SHOULD BE NEAR SW ARIZONA. STRATUS WILL AGAIN BE A PROBLEM THROUGH LATE MORNING BEFORE BURNING OFF DURING THE AFTERNOON HOURS. THIS WILL INITIALLY DAMPEN THE STANDARD DIURNAL CURVE BUT SHOULDNT EFFECT OVERALL TEMPERATURES WHICH SHOULD PUSH INTO THE MID 70S. STILL LOOKS LIKE A SLIGHT CHANCE OF THUNDERSTORMS IS WARRANTED ACROSS MOST OF THE FORECAST AREA BY MID TO LATE AFTERNOON ALONG A SURFACE TROUGH. EXACT POSITION OF THE TROUGH VARIES BETWEEN THE NAM/GFS/RUC13 SO SOMEWHAT BROADBRUSHED THE SLIGHT CHANCE POPS FOR NOW. SOME STRATUS RETURNS TO THE AREA AGAIN OVERNIGHT AS BOUNDARY LAYER MOISTURE INCREASES. RUC AND NAM SUGGEST THAT ANY ACTIVITY THAT DEVELOPS DURING THE LATE AFTERNOON HOURS WILL CONTINUE OR SLIGHTLY INCREASE IN COVERAGE THROUGH MIDNIGHT AS LOW LEVEL JET DEVELOPS. AROUND OR SHORTLY AFTER MIDNIGHT ANY PRECIP THAT DEVELOPS SHOULD HAVE QUICKLY MOVED NORTHEAST OF THE AREA. SATURDAY/SATURDAY NIGHT...WILL MAINTAIN HIGHEST POPS ACROSS THOSE COUNTIES EITHER SIDE OF THE CO/KS BORDER FOR THE AFTERNOON HOURS AS UPPER LOW REACHES CENTRAL NEW MEXICO. HAVE TRENDED TOWARD THE GFS AT THIS POINT FOR PLACEMENT OF HIGHEST POPS AS USED HPC QPF. WILL CONTINUE WITH SEVERE WORDING AS WELL. FOR SATURDAY NIGHT ALL MODELS EXCEPT THE GFS ARE IN GREAT AGREEMENT BRINGING THE UPPER LOW ATOP THE AREA BY 12Z SUNDAY. THE GFS IS ABOUT 6 HOURS FASTER. WILL GO WITH THE CONSENSUS AND KEEP HIGHEST POPS GENERALLY EAST OF THE CO/KS BORDER. HEAVY RAIN AND FLOODING REMAIN A THREAT AS STORMS REMAIN PARALLEL TO THE UPPER FLOW. HIGHS SATURDAY 70-75. SUNDAY/SUNDAY NIGHT...WRAPAROUND SHOWERS WILL LIFT NORTHEAST AND OUT OF THE AREA BY MID AFTERNOON ALONG WITH THE UPPER LOW. WILL NEED TO WATCH FOR FOG FORMATION SUNDAY NIGHT AS SOUTHEASTERLY WINDS DEVELOP AND GROUND SATURATED FROM THE EXPECTED RECENT RAINS. OTHER FEATURES OF INTEREST WILL BE ANOTHER LOW PRESSURE CENTER WHICH BY 12Z MONDAY SHOULD BE NEAR SOUTHWEST UTAH...DIVING SOUTHEAST. CURRENTLY EXPECT HIGHS IN THE MID TO UPPER 60S. IF THE PRECIP MOVES OUT FASTER THEN TEMPERATURES COULD BE A BIT WARMER THEN CURRENTLY EXPECTED. IF ITS SLOWER THEN WILL NEED TO TREND DOWNWARD. .LONG TERM (MONDAY-THURSDAY) NO CHANGES MADE. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ DDT ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 100 PM EDT SAT APR 21 2007 .AVIATION... HIGH PRESSURE WILL SLIDE TOWARD THE EAST COAST TONIGHT. VFR CLEAR CONDITIONS WILL BE IN PLACE TODAY THROUGH SUNDAY MORNING OUTSIDE OF A STRAY PATCH OF CIRRUS. SOUTHERLY COMPONENT TO THE WINDS THIS AFTERNOON AND TONIGHT...AND GENERALLY LESS THAN 10 KNOTS. AT DET AND DTW...WINDS WILL HAVE AN EASTERLY COMPONENT AS WELL FROM LAKE BREEZES FROM LAKE ERIE AND ST. CLAIR. BY SUNDAY MORNING...STRONGER GRADIENT BUILDS INTO LOWER MICHIGAN AND EXPECT SSW WIND TO INCREASE TO 12 TO 17 KNOTS. && .PREV DISCUSSION...ISSUED 1030 AM EDT SAT APR 21 2007 UPDATE... NOT MUCH TO UPDATE...JUST SOME MINOR GRIDS EDITS. THOSE MINOR EDITS WERE TO BRING MORE LAKE BREEZE IN THE WIND GRIDS...AND LOWER THE DEW POINTS AWAY FROM THE LAKE SHORES. RUC SURFACE WINDS WERE MUCH BETTER THAN NAM IN REGARD TO THE LAKE BREEZE. LAKE BREEZE SHOULD BE ABLE TO PUSH IN ABOUT 10 TO 15 MILES TODAY GIVE THE SURFACE HIGH OVER THE REGION AND THE LAND/LAKE TEMPERATURE DIFFERENCE. THEN THE DEW POINTS WERE RUNNING ABOUT 5 DEGREES ON EITHER SIDE OF 30 NOW THAT WE HAVE STARTED TO MIX THIS MORNING. DO NOT EXPECT THAT TO CHANGE THROUGH MUCH OF THE DAY GIVEN 12Z SOUNDING AND WEAK SURFACE WIND. TEMPS IN GENERAL RUNNING ABOUT 4 TO 7 DEGREES ABOVE YESTERDAYS. 12Z SOUNDING MIXING TO 750 MB...WHICH WE DID YESTERDAY...WOULD YIELD ABOUT 74. ALL OF THIS RIGHT IN LINE WITH CURRENT FORECAST. SHORT TERM...TODAY AND TONIGHT THE ONLY VARIATION ON THE THEME OF IDEAL WEATHER IN SE MICHIGAN TODAY AND TONIGHT WILL BE THE GRADUAL EASTWARD DRIFT OF THE SURFACE RIDGE AXIS. THIS WILL ALLOW A LIGHT SOUTHERLY GRADIENT FLOW TO DEVELOP DURING THE AFTERNOON WHICH WILL HELP HIGH TEMPERATURES RISE ABOUT A CATEGORY OVER YESTERDAY, MEANING MID 70S OVER SE LOWER AWAY FROM THE SHORELINES OF THE GREAT LAKES. AS WAS THE CASE OVER THE LAST COUPLE OF DAYS, WE WILL TAILOR HIGH TEMPERATURES COOLER IN THOSE AREAS IMPACTED BY AN EASTERLY COMPONENT OF LAKE BREEZE. THE MOST DRAMATIC ADJUSTMENT WILL BE NEAR THE LAKE HURON SHORELINE WHERE UPPER 50S WILL BE ALL THAT IS EXPECTED AFTER A CHILLY START TO THE DAY. HIGH PRESSURE WILL CONTINUE TO SLIDE EASTWARD TONIGHT AND INCREASE THE GRADIENT OVER SE MICHIGAN AS LOW PRESSURE DEVELOPS IN THE PLAINS. HOWEVER, THIS IS NOT EXPECTED TO RESULT IN MUCH OF AN INCREASE IN WIND SPEED AS STRONG DECOUPLING WILL OCCUR THROUGH THE NIGHT. THE RESULTING SLOW RETURN IN SURFACE MOISTURE WILL KEEP DEW POINT IN THE UPPER 30S AND ALLOW ANOTHER GOOD NIGHT OF RADIATIONAL COOLING. THAT BEING SAID, EVEN A 30 DEGREE DIURNAL SWING KEEPS READINGS IN THE LOWER TO MID 40S BY SUNRISE SUNDAY MORNING. LONG TERM... THE WARMEST DAY OF THE WEEK WILL OCCUR ON SUNDAY AS THE UPPER LEVEL RIDGE AXIS SLIDES JUST EAST OF THE CWA AND 850 MB TEMPS WARM INTO THE LOWER TEENS ALONG WITH AN INCREASING SOUTHWEST GRADIENT...LEADING TO MAXES IN THE MID TO UPPER 70S THROUGHOUT SOUTHEAST MICHIGAN UNDER MOSTLY SUNNY SKIES...AND POSSIBLY EVEN 80 DEGREES TOWARD THE TRI-CITIES REGION. EVEN SO...NOT PLANNING ON ISSUING A FIRE WX WATCH DUE TO THE RH EXPECTED TO REMAIN JUST ABOVE 25 PERCENT. 00Z NAM/GFS INDICATING SURFACE DEW POINTS CLIMBING INTO THE LOWER 50S. AFTER SUBTRACTING OUT THE MOIST LOW LEVEL BIAS OF THE MODELS (UP TO 10 DEGREES AS OBSERVED YESTERDAY)...STILL THINK IT WILL BE TOUGH TO MAINTAIN DEW POINTS BELOW 40 DEGREES WHICH WILL BE NEEDED TO SUPPORT RH`S AT OR BELOW 25 PERCENT. IT LOOKS TO REAL CLOSE CALL AND WOULD NOT TOTALLY RULE OUT A RED FLAG WARNING BEING NEEDED OVER MIDLAND/BAY/SAGINAW COUNTIES HOWEVER. GOOD AGREEMENT NOW WITH THE WEAKENING UPPER WAVE OVER FAR SOUTHERN CALIFORNIA TRACKING THROUGH THE CENTRAL GREAT LAKES ON MONDAY. INSTABILITY/MID LEVEL LAPSE RATES LOOK MARGINAL AND SUPPORT JUST A CHANCE OF THUNDERSTORMS LATE SUNDAY NIGHT INTO MONDAY. COLD FRONT EXPECTED TO BE SOUTH OF THE BORDER BY MONDAY EVENING...WITH NORTHWEST CONFLUENT FLOW AND GENERAL SUBSIDENCE OVERSPREADING LOWER MICHIGAN MONDAY NIGHT INTO TUESDAY...PER 00Z EUROPEAN. NORTHERN STREAM UPPER WAVE SLIDING OVER LAKE SUPERIOR TUESDAY EVENING WILL CAUSE 850-700 MB FGEN TO INCREASE ALONG WITH SIGNIFICANT MOISTURE TRANSPORT OVER SOUTHERN LOWER MICHIGAN...JUSTIFYING AT LEAST CHANCE POPS...HIGHEST POPS NEAR THE OHIO BORDER...CLOSER TO THE SURFACE BOUNDARY WHICH LOOKS TO RESIDE OVER THE NORTHERN OHIO VALLEY. THE 00Z GFS EVEN INDICATING THE SHOWALTER INDEX GOING NEGATIVE NEAR THE BORDER...AND HAVE ADDED A CHANCE OF THUNDERSTORMS ACROSS THE FAR SOUTH AS WELL. WILL ACCOUNT FOR THE POSSIBILITY OF SOME LINGERING SHOWERS ON WEDNESDAY AND TWEAK MAX TEMPS DOWN WITH THE NORTHEAST FLOW OFF LAKE HURON. OTHERWISE...NO CHANGES MADE BEYOND WEDNESDAY. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION...RBP SHORT TERM...BT/RBP LONG TERM....SF YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1032 AM EDT SAT APR 21 2007 .UPDATE... NOT MUCH TO UPDATE...JUST SOME MINOR GRIDS EDITS. THOSE MINOR EDITS WERE TO BRING MORE LAKE BREEZE IN THE WIND GRIDS...AND LOWER THE DEW POINTS AWAY FROM THE LAKE SHORES. RUC SURFACE WINDS WERE MUCH BETTER THAN NAM IN REGARD TO THE LAKE BREEZE. LAKE BREEZE SHOULD BE ABLE TO PUSH IN ABOUT 10 TO 15 MILES TODAY GIVE THE SURFACE HIGH OVER THE REGION AND THE LAND/LAKE TEMPERATURE DIFFERENCE. THEN THE DEW POINTS WERE RUNNING ABOUT 5 DEGREES ON EITHER SIDE OF 30 NOW THAT WE HAVE STARTED TO MIX THIS MORNING. DO NOT EXPECT THAT TO CHANGE THROUGH MUCH OF THE DAY GIVEN 12Z SOUNDING AND WEAK SURFACE WIND. TEMPS IN GENERAL RUNNING ABOUT 4 TO 7 DEGREES ABOVE YESTERDAYS. 12Z SOUNDING MIXING TO 750 MB...WHICH WE DID YESTERDAY...WOULD YIELD ABOUT 74. ALL OF THIS RIGHT IN LINE WITH CURRENT FORECAST. && .PREV DISCUSSION...ISSUED 647 AM EDT SAT APR 21 2007 SHORT TERM...TODAY AND TONIGHT THE ONLY VARIATION ON THE THEME OF IDEAL WEATHER IN SE MICHIGAN TODAY AND TONIGHT WILL BE THE GRADUAL EASTWARD DRIFT OF THE SURFACE RIDGE AXIS. THIS WILL ALLOW A LIGHT SOUTHERLY GRADIENT FLOW TO DEVELOP DURING THE AFTERNOON WHICH WILL HELP HIGH TEMPERATURES RISE ABOUT A CATEGORY OVER YESTERDAY, MEANING MID 70S OVER SE LOWER AWAY FROM THE SHORELINES OF THE GREAT LAKES. AS WAS THE CASE OVER THE LAST COUPLE OF DAYS, WE WILL TAILOR HIGH TEMPERATURES COOLER IN THOSE AREAS IMPACTED BY AN EASTERLY COMPONENT OF LAKE BREEZE. THE MOST DRAMATIC ADJUSTMENT WILL BE NEAR THE LAKE HURON SHORELINE WHERE UPPER 50S WILL BE ALL THAT IS EXPECTED AFTER A CHILLY START TO THE DAY. HIGH PRESSURE WILL CONTINUE TO SLIDE EASTWARD TONIGHT AND INCREASE THE GRADIENT OVER SE MICHIGAN AS LOW PRESSURE DEVELOPS IN THE PLAINS. HOWEVER, THIS IS NOT EXPECTED TO RESULT IN MUCH OF AN INCREASE IN WIND SPEED AS STRONG DECOUPLING WILL OCCUR THROUGH THE NIGHT. THE RESULTING SLOW RETURN IN SURFACE MOISTURE WILL KEEP DEW POINT IN THE UPPER 30S AND ALLOW ANOTHER GOOD NIGHT OF RADIATIONAL COOLING. THAT BEING SAID, EVEN A 30 DEGREE DIURNAL SWING KEEPS READINGS IN THE LOWER TO MID 40S BY SUNRISE SUNDAY MORNING. LONG TERM... THE WARMEST DAY OF THE WEEK WILL OCCUR ON SUNDAY AS THE UPPER LEVEL RIDGE AXIS SLIDES JUST EAST OF THE CWA AND 850 MB TEMPS WARM INTO THE LOWER TEENS ALONG WITH AN INCREASING SOUTHWEST GRADIENT...LEADING TO MAXES IN THE MID TO UPPER 70S THROUGHOUT SOUTHEAST MICHIGAN UNDER MOSTLY SUNNY SKIES...AND POSSIBLY EVEN 80 DEGREES TOWARD THE TRI-CITIES REGION. EVEN SO...NOT PLANNING ON ISSUING A FIRE WX WATCH DUE TO THE RH EXPECTED TO REMAIN JUST ABOVE 25 PERCENT. 00Z NAM/GFS INDICATING SURFACE DEW POINTS CLIMBING INTO THE LOWER 50S. AFTER SUBTRACTING OUT THE MOIST LOW LEVEL BIAS OF THE MODELS (UP TO 10 DEGREES AS OBSERVED YESTERDAY)...STILL THINK IT WILL BE TOUGH TO MAINTAIN DEW POINTS BELOW 40 DEGREES WHICH WILL BE NEEDED TO SUPPORT RH`S AT OR BELOW 25 PERCENT. IT LOOKS TO REAL CLOSE CALL AND WOULD NOT TOTALLY RULE OUT A RED FLAG WARNING BEING NEEDED OVER MIDLAND/BAY/SAGINAW COUNTIES HOWEVER. GOOD AGREEMENT NOW WITH THE WEAKENING UPPER WAVE OVER FAR SOUTHERN CALIFORNIA TRACKING THROUGH THE CENTRAL GREAT LAKES ON MONDAY. INSTABILITY/MID LEVEL LAPSE RATES LOOK MARGINAL AND SUPPORT JUST A CHANCE OF THUNDERSTORMS LATE SUNDAY NIGHT INTO MONDAY. COLD FRONT EXPECTED TO BE SOUTH OF THE BORDER BY MONDAY EVENING...WITH NORTHWEST CONFLUENT FLOW AND GENERAL SUBSIDENCE OVERSPREADING LOWER MICHIGAN MONDAY NIGHT INTO TUESDAY...PER 00Z EUROPEAN. NORTHERN STREAM UPPER WAVE SLIDING OVER LAKE SUPERIOR TUESDAY EVENING WILL CAUSE 850-700 MB FGEN TO INCREASE ALONG WITH SIGNIFICANT MOISTURE TRANSPORT OVER SOUTHERN LOWER MICHIGAN...JUSTIFYING AT LEAST CHANCE POPS...HIGHEST POPS NEAR THE OHIO BORDER...CLOSER TO THE SURFACE BOUNDARY WHICH LOOKS TO RESIDE OVER THE NORTHERN OHIO VALLEY. THE 00Z GFS EVEN INDICATING THE SHOWALTER INDEX GOING NEGATIVE NEAR THE BORDER...AND HAVE ADDED A CHANCE OF THUNDERSTORMS ACROSS THE FAR SOUTH AS WELL. WILL ACCOUNT FOR THE POSSIBILITY OF SOME LINGERING SHOWERS ON WEDNESDAY AND TWEAK MAX TEMPS DOWN WITH THE NORTHEAST FLOW OFF LAKE HURON. OTHERWISE...NO CHANGES MADE BEYOND WEDNESDAY. .AVIATION... HIGH PRESSURE WILL CONTINUE TO DOMINATE THE WEATHER FOR AVIATION INTERESTS TODAY BUT LOSE ITS GRIP A BIT TONIGHT WHILE SLIDING TOWARD THE EAST COAST. VFR CLEAR CONDITIONS WILL BE IN PLACE TODAY THROUGH TONIGHT OUTSIDE OF A STRAY PATCH OF CUMULUS OR PATCH OF CIRRUS. LIGHT AND VARIABLE WINDS WILL DEVELOP A SOUTHERLY COMPONENT BY AFTERNOON AND REMAIN LESS THAN 10 KNOTS TONIGHT. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION...BT SHORT TERM...BT/RBP LONG TERM....SF YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 350 AM EDT SAT APR 21 2007 .SYNOPSIS... 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR RDG CENTERED OVER THE GRT LKS BTWN TROFS IN THE WRN ATLANTIC AND OVER THE W. SFC HI CENTER OVER LWR MI AND DRY/STABLE AIRMASS (PWAT 0.40 INCH E TO 0.60 INCH W) SHOWN ON LOCAL 00Z RAOBS BRINGING A TRANQUIL NGT TO THE FA. CLOSEST PCPN IS SOME SHRA/ TSRA MOVING THRU WRN MN WHERE PAIR OF SHRTWVS NOTED BY RUC ANALYSIS MOVING NE THRU THE NRN PLAINS ON THE WRN FLANK OF UPR RDG INTERACTING WITH HIER H85 DWPTS/LLJ AXIS/MORE SGNFT MSTR CNVGC/AXIS OF H7-5 LAPSE RATE AOA 8C/KM. HI CLD BLOWING DOWNSTREAM FM THIS CLUSTER OF CNVCTN MOVING TOWARD WRN LK SUP. A MORE POTENT SHRTWV NOTED OVER SRN CA MOVING THRU THE BASE OF THE WRN TROF. ANOTHER SHRTWV NOTED OVER BRITISH COLUMBIA. MAIN FCST CONCERNS TDAY INTO SUN WL BE FIRE WX. FOCUS THEN SHIFTS TO PCPN CHCS ASSOCIATED WITH INTERACTION BTWN SHRTWV NOW OVER SRN CA AND THE OTHER NOW IN BRITISH COLUMBIA. FOR TDAY...NAM F0 APPEARS TO HAVE VERY GOOD HANDLE ON SHRTWV STRUCTURE/STABILITY/MSTR OVER THE NRN PLAINS/UPR LKS...SO WL FOLLOW ITS GUIDANCE. THIS MODEL SHOWS UPR RDG REMAINING PRETTY MUCH IN PLACE TDAY DOWNSTREAM OF STRONGER HGT FALLS OVER THE WRN PLAINS ASSOCIATED WITH POTENT SYS LIFTING OUT OF THE DESERT SW. SFC HI CENTER PROGGED TO DRIFT S TO NEAR CLE BY 00Z...WITH STRENGTHING SLY FLOW (H925 WINDS INCRSG TO 30KT BY 00Z SUN) BTWN THIS HI AND FALLING PRES OVER THE NRN PLAINS INTO MN. SHARP RDG FCST TO DEFLECT WEAKER SHRTWVS NOW MOVING THRU THE NRN PLAINS MORE NNE VS E...SO NAM FCST SHRA STAYING TO THE W SEEMS RSNBL. GFS ALSO IS DRY. WL HOWEVER MAINTAIN LO CHC POPS OVER WRN LK SUP CLOSER TO AXIS OF HIER RETURNING H85 DWPTS/KINX THRU MN AND WHERE SOME DEEP LYR H85-3 QVECTOR CNVGC NOTED. THERE SHOULD BE QUITE A BIT OF MID/HI CLD OVER THE W WITH MORE SUNSHINE TO THE E DEEPER INTO DRIER AIRMASS. MIXING TO H8 ON NAM FCST SDNGS YIELDS MAX TEMPS RISING TO ARND 73 OVER THE W...WITH DWPT ARND 40 (RH 30 PCT). AIRMASS WL REMAIN DRIER OVER THE E BUT TEMPS WL BE LOWER DOWNWIND OF LK MI. WL ISSUE WILDFIRE POTENTIAL STATEMENT TO STRESS NEAR CRITICAL FIRE WX PARAMETERS. TNGT...SHRTWV LIFTING OUT OF THE DESERT SW PROGGED TO REACH KS BY 12Z SUN WHILE SYS OVER BRITISH COLUMBIA FCST TO APRCH LK WINNIPEG. GUIDANCE SHOWS UPR RDG AXIS SHIFTING E A TAD...BUT GFS/NAM INDICATE ALL OF LAND FA WL REMAIN DRY WITH FCST SDNGS SHOWING A CAPPED WARM SECTOR. WL INCLUDE CHC SHRA/TSRA OVER WRN/NRN LK SUP AS SHRTWS MOVING ARND RDG AXIS PASS NW OF THE FA AND INTERACT WITH AXIS OF HIER H85 DWPT CLOSER TO EDGE OF CAP. GFS/NAM FCST H925 WINDS ARND 40KT ON WRN FLANK OF SFC HI MOVING INTO THE MID ATLANTIC...SO LOOK FOR RELATIVELY LTL DIURNAL DROP IN TEMP EVEN WHERE SKIES ARE MORE CLR OVER THE SCNTRL AND E. MIN TEMPS IN THE DOWNSLOPE AREAS FM IWD-P59-MQT-P53 WL NOT FALL BLO 50. GOING FCST LOOKS TO HAVE GOOD HANDLE ON PATTERN OF LO TEMPS...BUT BUMPED UP EXPECTED TEMPS IN DOWNSLOPE AREAS TOWARD HI END OF MOS GUIDANCE. NUMERICAL GUIDANCE IN GOOD AGREEMENT SHOWING SHRTWV LIFTING NEWD INTO THE UPR MS VALLEY BY 00Z MON AND WEAKENING AS SYS MOVES AWAY FM LARGER SCALE WRN TROF. MEANWHILE...OTHER SHRTWV MOVING ACRS SRN CAN PROGGED TO MOVE INTO NW ONTARIO LATE IN THE DAY. AS SHRTWVS CLOSE IN ON THE FA AND DEEP LYR H85-3 QVECTOR CNVGC ARRIVING IN THE AFTN... MODELS SHOW SUBSTANTIAL CAPPING OVER THE NW ERODING BTWN 18Z-24Z. GFS IS PARTICULARLY AGGRESSIVE AT MOISTENING THE ATMOSPHERE AND GENERATING QPF OVER THE W. CONSIDERING THE DRY AND CAPPED ANTECEDENT AIRMASS AND THE VERY LATE ARRIVAL OF THE MORE SGNFT DYNAMICS WITH THE SHRTWV PAIR REMAINING OUT OF PHASE...PREFER THE SLOWER NAM. THIS MODEL GENERATES ONLY A FEW HUNDREDTHS OF AN INCH AT IWD BEFORE 00Z MON. THE UKMET IS ALSO SLOWER TO SATURATE THE AIR OVER THE FAR W AS WELL. LARGE SCALE ACYC H85 FLOW FCST AHEAD OF THE SHRTWV COMPLEX... SO PCPN IS LIKELY TO HOLD OFF UNTIL THE SFC FNT ACCOMPANYING THE ONTARIO SHRTWV PASSES AND FAIRLY SHARP H85-7 FGEN ARRIVES SUN EVNG...WL KEEP THE LAND FA DRY ON SUN. FARTHER E...PCPN ON SUN IS A NON ISSUE WITH CAPPED ENVIRONMENT ALL DAY. MIXING TO H825 OR SO ON NAM FCST SDNGS IN THE WARM SECTOR SUG HI TEMPS WL APRCH 80 AWAY FM THE MODERATING INFLUENCE OF LK MI. SINCE RELATIVELY DEEP MIXING WL ALSO TAP DRIER LYR FCST ARND H85...DWPTS COULD MIX OUT INTO THE MID-UPR 30S IN THE AFTN OVER THE E AND DROP THE RH TOWARD 25 PCT IN AREAS THAT ESCAPE SGNFT COOLING DOWNWIND OF LK MI. SFC LO/LO PRES TROF ASSOCIATED WITH SHRTWV MOVING UP FM THE UPR MS VALLEY PROGGED TO REACH THE SRN ZNS BY 12Z MON WHILE SFC COLD FNT ACCOMPANYING SHRTWV MOVING ACRS ONTARIO REACHES THE CNTRL ZNS PER PREFERRED NAM/UKMET. PRETTY MUCH MAINTAINED GOING FCST OF LIKELY POPS ADVANCING W-E WITH THESE FEATURES. SINCE MODELS CONSISTENTLY SHOW PAIR OF SHRTWVS REMAINING OUT OF PHASE...SUSPECT ACCOMPANYING SHRA WL NOT BE TOO HEAVY WITH FAIRLY HEALTHY H85-7 FGEN BEHIND NRN BRANCH COLD FNT TENDING TO STAY FARTHER N. FCST SDNGS SHOW RATHER UNIMPRESSIVE LAPSE RATES...SO CALLED PCPN LIKELY -SHRA WITH JUST A CHC T. SINCE EVEN THE SLOWER NAM/UKMET BRING MUCH DRIER E INTO THE FA ON MON AFTN...CUT POPS W-E FASTER THAN PREVIOUS FCST. GFS SHOWS NEXT SHRTWV LIFTING OUT OF THE SW FARTHER N TOWARD THE UPR MIDWEST ON TUE WITH SOME LGT QPF OVER THE SRN TIER. UNTIL GUIDANCE COMES INTO BETTER AGREEMENT...FOLLOWED THE MORE CONSISTENT ECMWF/CNDN MODELS... WHICH SHOW THIS SYS/HIER RH REMAINING FARTHER S. SO NO CHGS MADE TO DRY TUE FCST. COORDINATED WITH APX/GRB. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 355 AM EDT FRI APR 20 2007 .DISCUSSION... 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW HI AMPLITUDE HUDSON BAY HI PRES RDG SANDWICHED BTWN RDG OFF THE E COAST AND ANOTHER OVER THE PAC NW. QUIET NITE OVER THE FA WITH HI PRES RDG AXIS AND DRY STABLE AIRMASS DEPICTED ON THE 00Z GRB RAOB/01Z TAMDAR SDNG FM SAW DOMINATING. SHRTWV OVER THE NRN PLAINS IS ROTATING ALMOST DUE N ON THE ERN FLANK OF NW TROF...SO ASSOCIATED MID/HI CLD MAKING ONLY SLOW PROGRESS EWD THRU MN E TOWARD THE UPR LKS WITH SE TRAJECTORIES MAINTAINING DRY AIRMASS AT INL AS WELL. JUST A BIT HIER RH NOTED ON THE 00Z INL SDNG AT THE TOP OF THE PBL...BUT ASSOCIATED DIURNAL CU DSPTD SOON AFT SUNSET. ANOTHER MORE POTENT SHRTWV DROPPING THRU WRN TROF TOWARD THE SW CONUS. MAIN FCST CONCERNS INTO SAT ARE TEMPS/FIRE WX ISSUES WITH DRY RDG PROGGED TO REMAIN DOMINANT. AS RDG BREAKS DOWN OVER THE WEEKEND AND SHRTWV NOW MOVING TOWARD THE SW CONUS LIFTS TO THE NE...FOCUS WL SHIFT TOWARD TIMING ARRIVAL OF ANY ASSOCIATED PCPN. EXPECT ANOTHER QUIET DAY OVER THE FA TDAY UNDER SFC RDG. CENTER OF SFC HI PRES PROGGED TO SHIFT OVER THE CNTRL GRT LKS UNDER RISING UPR HGTS...SO LLVL FLOW WL SHIFT TO MORE SLY...ESPECIALLY OVER THE WRN ZNS. WITH REDUCED LK MODERATION AND H85 TEMPS PROGGED TO RISE TO 6C OVER THE W BY 00Z SAT...EXPECT HI TEMPS OVER THE WCNTRL INTERIOR TO REACH APRCH 70 PER MIXING TO H8 ON GFS/NAM FCST SDNGS. OTHER THAN SOME DIURNAL CU AND SOME HI CLD OVER THE W ASSOCIATED WITH NRN PLAINS TROF LIFTING N INTO CAN...SKIES WL BE SUNNY. MIXING TO H8 WL ALLOW SFC DWPTS TO FALL TOWARD 32 IN THE AFTN...WITH MIN RH FALLING TOWARD 25 PCT. RELATIVELY LGT WINDS WL KEEP OVERALL FIRE WX SITUATION FM BECMG TOO CRITICAL. UPR RDG FCST TO DOMINATE AGAIN TNGT...SO EXPECT A QUIET PD WITH MOCLR SKIES AGAIN. HI PRES CENTER FCST TO MOVE TO NEAR DTX BY 12Z SAT...SO RETURN SW FLOW WL HOLD MIN TEMPS HIER THAN THIS MRNG WITH H925 WINDS 15 TO 20 KT. EXPECT THE LOWEST READINGS OVER THE INTERIOR SCNTRL AND E. SHRTWV NOW MOVING INTO THE SW CONUS FCST TO BEGIN TO ROUND THE BASE OF WRN TROF AND LIFT INTO THE PLAINS ON SAT. WITH FALLING PRES IN THE PLAINS AHEAD OF THIS SYS AND SFC HI PRES RDG MOVING SLOWLY TO THE E...PRES GRADIENT/SSW FLOW FCST TO INCRS OVER THE UPR LKS DURING THE DAY. OPTED TO REMOVE PCPN OVER THE LAND FA ON SAT GIVEN STRENGTH OF RDG/ANTECEDENT DRY AIRMASS...BUT TENDED TO KEEP LO CHC POPS OVER WRN LK SUP AS GFS/UKMET/ECMWF HINT AT A FEW WEAK DISTURBANCES RIDING OVER THE TOP OF THE RDG TO THE NW AND INTERACTING WITH LLVL MSTR RETURN. MIXING TO H8 ON GFS/NAM FCST SDNGS WOULD ALLOW TEMPS TO RISE INTO THE LO 70S AWAY FM MODERATION OFF LK MI. THE NAM AND ESPECIALLY THE GFS SHOW QUITE A BIT MORE LLVL MSTR RETURNING OVER THE W...WITH MIXING TO H8 INDICATING DWPTS WOULD FALL OFF TO ONLY 40 TO 45. THE NAM IS NOT AS AGGRESSIVE WITH LLVL MSTR RETURN...AND MIXING TO H8 WOULD ALLOW THE DWPT TO FALL TO ONLY ABOUT 37 (RH CLOSE TO 25 PERCENT). TEND TO PREFER THE DRIER NAM IDEA AT THIS POINT CONSIDERING THE SLOWER EXPECTED BREAKDOWN OF THE RDG IN PRESENT HI AMPLITUDE PATTERN. COMBINATION OF INCRSG WINDS...MIXING OF FAIRLY DRY AIR...AND TEMPS REACHING AOA 70 AT A FEW PLACES WL PUSH OVERALL FIRE WX PARAMETERS TO NEAR CRITICAL LVLS. GFS/NAM SHOW H925 SW WINDS REACHING 35 TO 40 KTS SAT NGT IN A CAPPED WARM SECTOR...SO EXPECT A RELATIVELY NEGLIGIBLE DIURNAL TEMP DROP. READINGS IN THE DOWNSLOPE AREAS FM P53-MQT-P59-IWD MAY NOT DROP BLO 50. RESTRICTED POPS ON SAT TO OVER LK SUP CONSIDERING CAPPED FCST SDNGS IN WARM SECTOR. SUN WL BE A VERY WARM DAY WITH STRONG SW FLOW CONTINUING AHEAD OF SHRTWV SLOWLY LIFTING NE. CONSIDERING EXPECTED SLOWER APRCH OF SHRTWV AND MORE SUNSHINE COUPLED WITH H85 TEMPS APRCHG 15C...GOING FCST HI TEMPS IN THE MID TO UPR 70S AWAY FM LK MI MODERATION LOOK ON TRACK. PER NCEP GUIDANCE...FOLLOWED THE UKMET/NAM SOLNS MORE THAN THE GFS. THESE MODELS HINT AT MORE LLVL MSTR AND SFC DWPTS IN THE 40 TO 45 RANGE...WHICH WOULD KEEP THE RH IN THE 25 TO 30 PCT RANGE. TRENDED TOWARD THE SLOWER NAM/UKMET/CNDN MODELS ON FCST PROGRESSION OF SYS LIFTING OUT OF THE SW...SO CUT POPS SUN NGT. COORDINATED WITH APX/GRB. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 304 PM CDT SAT APR 21 2007 .DISCUSSION... SHOWERS AND THUNDERSTORMS PERSISTED TODAY ALONG A THERMAL AXIS FROM THE ARROWHEAD...TO THE TWIN PORTS...AND SOUTH ALONG THE I-35 CORRIDOR. ALTHOUGH THE TSTMS BECAME LESS WIDESPREAD IN THE AFTERNOON HOURS. A STRONG SW LL FLOW ALLOWED FOR THE STORMS TO MOVE VERY QUICKLY TO THE NNE AT 40 TO 45 KT. ALTHOUGH NO WIND DAMAGE WAS REPORTED WITH THE FAST MOVING STORMS...PLENTY OF HALF INCH HAIL ACCOMPANIED THESE CELLS. THE THERMAL RIDGE HAS DRIFTED ABOUT 30 MILES EAST FROM THIS MORNING AND IS NOW ALONG A LINE FROM BAYFIELD TO RICE LAKE...AND INTO THE ERN TWIN CITIES METRO. THE RUC ALSO SHOWS THIS REGION IS CO-LOCATED WITH A NARROW AREA OF MAX ISENTROPIC LIFT AS WELL AS BOUNDARY LAYER MASS CONVERGENCE. THESE FAST MOVING SHOWERS AND THUNDERSTORMS WITH SMALL HAIL WILL CONTINUE TO TRACK NE ALONG THE THERMAL RIDGE IN NW WIS THIS EVENING...DIMINISHING AFTER SUNSET. FORECAST FOCUS TURNING TO THUNDERSTORMS OVERNIGHT AS ON SUNDAY AS A LOW PRESSURE SYSTEM AND DEVELOPING COLD FRONT AFFECT THE REGION. SOME OF THE STORMS COULD BE SEVERE SUNDAY AFTERNOON IN NORTHERN WISCONSIN. OVERNIGHT...SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP AS A 50 KT SW LLJ ENTERS THE ERN HALF OF THE CWA. THE FOCUS FOR ACTIVITY OVERNIGHT AND SUNDAY MORNING WILL BE ALONG A STRONG THERMAL BOUNDARY AHEAD OF COLD FRONT IN WRN AND NRN MN. MINOR CHANGES TO POPS OVERNIGHT. ALTHOUGH NAM/GFS ARE IN SIMILAR AGREEMENT WITH THE PLACEMENT OF THE FRONT AND THE MAX QPF OVERNIGHT...THE GFS IS STRONGER AND DEEPENS THE SFC FRONT INTO A 998 LOW IN NC MN BY SUNDAY MORNING. DUE TO THE POOR HANDLING OF THE LINE OF STORMS TODAY...SIGNIFICANT FURTHER SE THAN MODELS DEPICTED...DECREASED CONFIDENCE IN THE MODELS PLACEMENT OF THE QPF OVERNIGHT. TOMORROW...THE COLD FRONT WILL PUSH SE ACROSS NW MN SUNDAY MORNING...DECREASING THE CHANCE FOR ADDITIONAL TSTMS BEHIND IT. MUCH DRIER AIR AND CAA WILL FILTER INTO NW MN BY SUNDAY AFTERNOON. THE EXTEND OF THE DRY AIR IS STILL SOMEWHAT UNCERTAIN...BUT THE GFS AND NAM ARE BRINING IT FURTHER SE INTO THE CWA BY SUNDAY AFTERNOON. THIS DRY AIR WILL DECREASE THE CHANCE FOR THE NW THIRD OF THE CWA TO SEE ANY STORMS SUNDAY AFTERNOON AND EVENING. THE MODELS ARE ALSO TRENDING WITH A FASTER FROPA SUNDAY AND SUNDAY NIGHT. ADJUSTED POPS TO REFLECT THEES TRENDS. STORMS ARE LIKELY TO FIRE SUNDAY AFTERNOON AND EVENING...GENERALLY ALONG AND SOUTH OF A LINE FROM CASS LAKE...TO HIBBING...AND INTO THE MN ARROWHEAD. THE STRONGER STORMS ARE EXPECTED ACROSS ALL OF WI AND INTO SW MN...WHERE THERE IS A SLIGHT RISK FOR SEVERE THUNDERSTORMS. MUCAPE VALUES SUNDAY AFTN/EVEN ARE EXPECTED TO MAX OUT BETWEEN 1000 AND 1500 J/KG...WHILE 0-3KM SRH VALUES ARE PROGGED TO RANGE FROM 100-200 J/KG...WHICH SHOULD BE SUFFICIENT FOR THE DEVELOPMENT FOR ISOLATED SEVERE THUNDERSTORMS. REFER TO THE THE DAY TWO SPC OUTLOOK FOR FURTHER DETAILS. THE FRONT WILL MOVE EAST OF OUR FA SUNDAY NIGHT...ALTHOUGH SOME SHOWER ACTIVITY SHOULD LINGER ACROSS OUR ERN ZONES THROUGH MONDAY MORNING. HIGH PRESSURE WILL BUILD ACROSS THE UPPER MIDWEST MONDAY AND MONDAY NIGHT...RESULTING IN A DRYING TREND. TEMPERATURES WILL REMAIN ABOVE NORMAL THIS WEEKEND...WITH COOLER TEMPS THEN EXPECTED FOR NEXT WEEK ASSOCIATED WITH THE AFOREMENTIONED HIGH PRESSURE SYSTEM FROM CANADA. && POINT TEMPS/POPS... DLH 47 64 41 57 / 30 70 70 10 INL 49 62 37 49 / 70 60 10 10 BRD 55 65 43 62 / 40 70 70 10 HYR 55 71 44 60 / 10 60 80 10 ASX 53 70 42 57 / 10 70 70 10 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. $$ GRANING mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 915 AM CDT SAT APR 21 2007 .UPDATE... A LINE OF SHOWERS AND THUNDERSTORMS HAS SHIFTED EAST WHILE THE STORM TRACK TO THE NNE. THE LINE OF STRUMS EXTENDS FROM ELY...SOUTH THROUGH THE TWIN PORTS...AND ALONG THE I-35 CORRIDOR INTO THE TWIN CITES. RUC 925MB WINDS ALONG AND AHEAD OF THE LINE ARE UPWARDS OF 30KT FROM THE SOUTH...WITH A NOSE OF MAX H850 TEMPS AND WAA FEEDING INTO THE LINE OF STORMS. AT 9 AM...SMALL HAIL OF 1/4 INCH WAS REPORTED IN HINCKLEY. INCREASED THE LIKELY TSTM POPS FURTHER EAST THIS MORNING. && .PREV DISCUSSION... /ISSUED 327 AM CDT SAT APR 21 2007/ DISCUSSION...A LINE OF SHOWERS AND THUNDERSTORMS...REMNANTS OF STRONGER THUNDERSTORMS OVER THE DAKOTAS...HAS FINALLY BEGUN TO AFFECT OUR WRN COUNTIES EARLY THIS MORNING. SOME GUSTY WINDS HAVE BEEN ASSOCIATED WITH STRONGER STORMS...BUT THESE GUSTS HAVE BEEN FAIRLY MODEST. WE EXPECT THESE LINE OF STORMS TO SLOWLY SPREAD TO THE EAST...HOWEVER IT IS MOST LIKELY THEY WILL NOT REACH THE TWIN PORTS DUE TO DRIER AIR BEING ADVECTED IN FROM THE EAST. WE WILL MENTION LIKELY POPS FOR TODAY ACROSS OUR WRN COUNTIES AND THE NORTHERN HALF OF SAINT LOUIS COUNTY AS BOTH THE GFS AND NAM FORECAST PRECIP IN THESE AREAS...WHICH IS ASSOCIATED WITH A FEW WEAK UPPER LEVEL VORTICITY MAXIMA LIFTING ACROSS THE NRN PLAINS. FOR TONIGHT...SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP AND CONTINUE TO AFFECT WRN AND NRN MINNESOTA WHERE LIFT ASSOCIATED WITH A DEVELOPING COLD FRONT WILL BE FOCUSED. THIS FRONT ALONG WITH A STRONGER UPPER LEVEL SHORTWAVE WILL BE THE MAIN FORECAST CONCERN THROUGH SUNDAY NIGHT AS THEY TRACK EASTWARD ACROSS OUR CWA...ESPECIALLY SUNDAY AFTERNOON AND SUNDAY EVENING WHEN THERE WILL BE A SLIGHT RISK FOR SEVERE THUNDERSTORMS. MUCAPE VALUES DURING THIS TIME FRAME ARE EXPECTED TO MAX OUT BETWEEN 1000 AND 1500 J/KG...WHILE 0-3KM SRH VALUES ARE PROGGED TO RANGE FROM 100-200 J/KG...WHICH SHOULD BE SUFFICIENT FOR THE DEVELOPMENT FOR ISOLATED SEVERE THUNDERSTORMS. THE FRONT WILL MOVE EAST OF OUR FCST AFTER MIDNIGHT SUNDAY NIGHT...ALTHOUGH SOME SHOWER ACTIVITY SHOULD LINGER ACROSS OUR ERN ZONES THROUGH MONDAY MORNING. HIGH PRESSURE WILL BUILD ACROSS THE UPPER MIDWEST MONDAY AND MONDAY NIGHT...RESULTING IN A DRYING TREND. TEMPERATURES WILL REMAIN ABOVE NORMAL THIS WEEKEND...WITH COOLER TEMPS THEN EXPECTED FOR NEXT WEEK ASSOCIATED WITH THE AFOREMENTIONED HIGH PRESSURE SYSTEM FROM CANADA. && POINT TEMPS/POPS... DLH 63 49 63 41 / 60 30 70 70 INL 67 50 62 37 / 60 60 70 70 BRD 73 54 65 43 / 60 40 70 50 HYR 74 54 71 44 / 10 10 40 70 ASX 73 53 70 42 / 10 10 40 70 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. $$ GRANING mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 620 PM CDT FRI APR 20 2007 .UPDATE...FOR 00Z TAF CYCLE BELOW. && .PREV DISCUSSION.../ISSUED 314 PM CDT FRI APR 20 2007/ DISCUSSION... THUNDERSTORMS AT MID AFTERNOON OVER NE SD IN ZONE OF STRONG 850-700MB THETA-E ADVECTION...700-500MB LAPSE RATES AROUND 7 DEG C/KM ALONG WITH THE NOSE OF A 35-40 KNOT SOUTHERLY LOW LEVEL JET. THE LOW LEVEL JET IS FORECAST TO INCREASE TO NEAR 50 KNOTS TONIGHT WHILE PROGRESSING INTO NW MN. A SURGE IN THE 305K MOISTURE TRANSPORT VECTORS IS SEEN ON THE GFS INTO WEST CENTRAL MN THIS EVENING AND INTO CENTRAL MN AFTER MIDNIGHT. BEST LI`S ALSO GO NEGATIVE WITH TIME AS WELL. THEREFORE HAVE CONTINUED WITH A CHANCE OF THUNDERSTORMS SPREADING INTO WEST CENTRAL AND PORTIONS OF CENTRAL MN OVERNIGHT. MAINTAINED SMALL CHANCES OF CONVECTION OVER THE NORTHWEST CWA ON SATURDAY WHILE THE REST OF THE FA IS DRY...QUITE BREEZY AND VERY WARM. AN UPPER LOW WILL BE LIFTING NORTHEAST OVER THE WEEKEND FROM THE SOUTHWESTERN U.S. WITH A SURFACE FRONTAL BOUNDARY STRETCHING FROM EASTERN NE THROUGH NW MN INTO SUNDAY. HENCE...THE FOCUS OF STRONG TO SEVERE STORMS WILL BE OVER EASTERN SD AND WEST CENTRAL MN THROUGH SATURDAY NIGHT. THE FRONTAL BOUNDARY SHOULD BEGIN CREEPING EASTWARD ON SUNDAY AS THE UPPER LOW GETS CLOSER AND BEGINS TO OPEN UP. THIS PLACES EASTERN MN AND WESTERN WI IN THE HOT SEAT FOR A CHANCE OF SEVERE WEATHER SUNDAY AFTERNOON AND EVENING. MUCH WILL DEPEND ON THE AMOUNT OF SUNSHINE AND BOUNDARY INTERACTION. SHOWERS TO END OVER EASTERN MN BY MONDAY MORNING AND OVER WEST CENTRAL WI BY MONDAY AFTERNOON. STILL SOME UNCERTAINTY WITH YET ANOTHER UPPER LOW COMING OUR WAY FOR TUESDAY AND WEDNESDAY FROM THE SOUTHWEST. GFS ENSEMBLE FOCUSES THE BULK OF THE PRECIPITATION FROM SOUTH CENTRAL MN ON SOUTHWARD AND CHANCE POPS IN PLACE ATTM. ANOTHER CHANCE FOR SHOWERS LATE IN THE WEEK WITH A COOL FRONT DROPPING SOUTHEAST ACROSS THE FA. HIGH TEMPERATURES SATURDAY PUSHED UP SOME MORE WITH HIGHS IN THE UPPER 70S FROM MSP ON EAST AND SOUTH. RAISED LOWS AS WELL SATURDAY NIGHT INTO THE MIDDLE AND UPPER 50S. LOWS/HIGHS NEXT WEEK CLOSE TO HPC VALUES WITH ONLY MINOR TWEAKS MADE. && .AVIATION...THE MAIN AVIATION CONCERN IS THE POTENTIAL FOR LOW CLOUD /MVFR CATEGORY/ DEVELOPMENT OVER WESTERN MN LATE TONIGHT INTO EARLY SATURDAY MORNING...ON THE NORTHEASTERN PERIPHERY OF THE SURFACE TROUGH OVER THE WESTERN DAKOTAS. PER PROGGED RUC/NAM 900MB CONDENSATIONAL PRESSURE DEFICITS...AFOREMENTIONED MVFR CONDITIONS ARE EXPECTED AROUND DAYBREAK AT AXN...WHILE OTHER TAF SITES SHOULD EXPERIENCE SCT-BKN VFR CLOUDS THROUGH THE PERIOD. MAY ALSO SEE SOME SCATTERED SHOWERS SNEAK INTO AXN/STC/RWF OVERNIGHT ON THE NOSE OF A 40 KNOT LOW LEVEL JET. HAVE MAINTAINED A MENTION OF THUNDER FOR AXN WHERE INSTABILITY IS HIGHER. MODERATE TO STRONG SOUTHEAST WINDS WILL CONTINUE TONIGHT...WITH A SLIGHT VEERING TOWARD TRUE SOUTHERLY ON SATURDAY. A TIGHTENING SFC PRESSURE GRADIENT WILL YIELD STRENGTHENING WINDS ON SATURDAY...WITH GUSTS BETWEEN 30 AND 35 MPH LIKELY DURING THE AFTERNOON. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ LS/RAH mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 430 AM CDT SAT APR 21 2007 .SHORT TERM...TODAY THROUGH SUNDAY...CONTINUED WARM AND DRY THIS WEEKEND AS HIGH PRESSURE SFC AND ALOFT DOMINATE OVER OUR REGION. WATER VAPOR IMAGERY/RUC ANALYSIS THIS MORNING SHOWS A FAIRLY AMPLIFIED PATTERN OVER THE CONUS WITH A WELL DEFINED LOW SPINNING OVER SOUTHERN CALIFORNIA AND A RATHER LARGE RIDGE OVER THE MS VALLEY. THE MID/UPPER RIDGE WILL SHIFT SLOWLY EAST ACROSS OUR CWA THIS WEEKEND AND DEFLECT THE LOW OVER SOUTHERN CALIFORNIA TO THE NORTHEAST OVER THE CENTRAL PLAINS. AT THE SFC...HIGH PRESSURE CENTERED OVER THE OHIO VALLEY THIS MORNING WILL MOVE SOUTHEAST OVER THE CENTRAL APPALACHIANS TODAY AND TO THE CAROLINA COAST BY SUNDAY AFTERNOON. THIS WILL RESULT IN OUR LOW LEVEL FLOW GRADUALLY VEERING FROM EASTERLY THIS MORNING TO SOUTHEASTERLY THIS AFTERNOON AND SOUTHERLY SUNDAY. LOW LEVEL MOISTURE WILL SLOWLY INCREASE AS A RESULT. PLENTY OF INSOLATION IS EXPECTED TODAY WITH LITTLE CLOUD COVER. THERE WILL BE A FEW MORE MID TO HIGH LEVEL CLOUDS AROUND SUNDAY FROM THE CONVECTION GENERATED TO OUR WEST ASSOCIATED WITH THE UPPER LOW. THIS WILL DO LITTLE TO PREVENT US FROM REACHING AFTERNOON MAX TEMPS A FEW DEGREES ABOVE NORMAL. AFTERNOON MAXIMUM TEMPERATURES WILL BE AROUND 80 DEGREES THIS AFTERNOON AND AGAIN SUNDAY. WITH CLEAR SKIES AND LIGHT WINDS EXPECTED AGAIN TONIGHT...SUNDAY MORNING LOWS WILL AGAIN BE A FEW DEGREES BELOW NORMAL...IN THE LOWER 50S AT MOST SITES. /22/ .LONG TERM...(SUNDAY NIGHT THROUGH NEXT SATURDAY)... GENERALLY UNEVENTFUL WEATHER SHOULD CONTINUE DURING THE SUNDAY NIGHT THROUGH TUESDAY PERIODS AS UPPER LEVEL RIDGING REMAINS THE PREDOMINANT INFLUENCE OVER THE ARKLAMISS. A DISTURBANCE PASSING OFF TO THE NORTH OF THE REGION LATE SUNDAY WILL LIKELY GENERATE SOME THUNDERSTORMS SUNDAY NIGHT NORTHWEST OF MY BORDERS...AND THEN DRAG A WEAK BOUNDARY SOMEWHAT CLOSE TO THE NORTHERN BORDERS OF THE FORECAST AREA THROUGH EARLY MONDAY. NOT ANTICIPATING ANY PRECIP TO GET INTO THE REGION WITH THIS SYSTEM...BUT RENEWED SOUTHERLY FLOW IN WESTERN ZONES WILL BRING A LITTLE MOISTURE NORTH FROM THE GULF. AFTER THIS SYSTEM...ALL THOSE LOOKING FOR RAIN WILL HAVE TO WAIT A FEW MORE DAYS FOR A MORE PROMISING DISTURBANCE SET TO SWING THROUGH LATE WEDNESDAY THROUGH THURSDAY. OPERATIONAL GFS MODEL HAS BEEN TRENDING WEAKER WITH THIS SYSTEM...TRYING TO DAMPEN IT SIGNIFICANTLY AS IT CROSSES OUR LONGITUDE. MEANWHILE...THE LATEST EUROPEAN MODEL RUN KEEPS THE SYSTEM MORE ROBUST THROUGH THE AXIS OF THE MID AND LOWER MISSISSIPPI VALLEYS. THE LATTER SOLUTION WOULD RESULT IN MORE PRECIPITATION A BETTER CHANCE OF STRONG CONVECTION. RIGHT NOW I`M LEANING ON THE EUROPEAN SOLUTION SINCE THAT MODEL HAS BEEN MORE CONSISTENT WITH THE HANDLING OF THIS SYSTEM AND HAS GENERALLY HAD MORE SKILL IN THE LONG-RANGE PORTION OF THE FORECAST LATELY. THOSE LOOKING TO AVOID DROUGHT SHOULD WISH FOR A GOOD SOAKING WITH THIS SYSTEM AND HOPEFULLY WE CAN AVOID SEVERE WEATHER. I AM STILL GOING TO LEAVE THE HWO CLEAR WITH REGARDS TO THE THIS SYSTEM FOR THE PRESENT TIME CONSIDERING QUESTION MARKS RELATING TO MOISTURE RETURN (AND ASSOCIATED INSTABILITY) AND OVERALL STRENGTH OF SYSTEM. THOSE UNCERTAINTIES SHOULD BE RESOLVED IN THE NEXT FEW DAYS. MODELS (SPECIFICALLY THE OPERATIONAL GFS AND OPERATIONAL EUROPEAN) DEVIATE EVEN MORE TOWARD THE END OF THE LONG TERM PERIOD. THE GFS SUGGESTS ANOTHER RATHER STRONG DISTURBANCE WILL MARCH ACROSS THE REGION AROUND SATURDAY...ACTIVATING THE BAROCLINIC ZONES LEFT IN THE WAKE OF WEDNESDAY/THURSDAY`S SYSTEM. THE END RESULT WOULD BE ANOTHER GOOD SHOT AT RAIN FOLLOWED BY A COOL SHOT. AT THE OTHER END OF THE SPECTRUM...THE EUROPEAN MODEL DOES NOT PHASE THIS DISTURBANCE LIKE THE GFS...INSTEAD LEAVING IT ABANDONED IN THE MIDDLE OF THE NATION. THAT SCENARIO WOULD LEAVE US WARM AND GENERALLY DRY THROUGH NEXT SATURDAY...ALTHOUGH SOME ISOLATED SHOWERS STILL COULD NOT BE RULED OUT GIVEN THE EXPECTATION OF A MEANDERING BOUNDARY IN THE VICINITY. BOTH MODELS HAVE BEEN CONSISTENT WITH THEIR RESPECTIVE SOLUTIONS THE PAST FEW DAYS AND VARIOUS OTHER MODELS AND ENSEMBLES ARE NOT HELPING TO RESOLVE DIFFERENCES MUCH. STILL HAVE TO HEDGE TOWARD THE EURO RIGHT NOW THOUGH...MAINLY BECAUSE ITS RECENT PERFORMANCE IN THE LONG RANGE HAS BEEN SUPERIOR. SO...AFTER A COOLER THAN AVERAGE APRIL THUS FAR WE CAN ANTICIPATE TEMPERATURES TO BE GENERALLY ABOVE AVERAGE THROUGH MOST OF THE REST OF THE MONTH. THAT EQUATES TO LOWS RANGING FROM THE UPPER 50S TO LOWER 60S WITH HIGHS RANGING MAINLY FROM 80 TO 85 DEGREES. THAT SAID...THE EURO MODEL DOES SUGGEST A BIT OF COOLING BEHIND THE COMING FRONT NEXT THURSDAY...BUT ANY SUB-80 DEGREE WEATHER WILL PROBABLY NOT LAST TOO LONG. GIVEN MY MENTIONED DISAGREEMENTS WITH THE OPERATIONAL GFS MODEL...IT IS NOT SURPRISING THAT I DEVIATED FROM GFS POP AND TEMP GUIDANCE A BIT THROUGH THE LONG TERM. FOR TEMPS...I GENERALLY WENT 1 TO 2 DEGREE WARMER THAN GUIDANCE FOR HIGHS (ESPECIALLY EAST) MONDAY THROUGH WEDNESDAY. FOR LOW TEMPS I CUT GUIDANCE A TOUCH SUNDAY AND MONDAY NIGHTS DUE TO DRY AIR IN PLACE...AND THEN AGAIN THURSDAY AND FRIDAY NIGHT SINCE I FEEL A LITTLE COOL AIR MAY WORK SOUTH INTO THE ARKLAMISS IN THE WAKE OF THE FRONTAL PASSAGE. AS FOR POPS...GFS GUIDANCE GENERATES SOME SPURIOUS LOOKING POPS MONDAY NIGHT THROUGH TUESDAY NIGHT WITH VERY MINOR IMPULSES EJECTING OUT OF THE APPROACHING LARGER DISTURBANCE. FEELING IS THAT GENERALLY STABLE AND CAPPED AIRMASS IN OUR AREA WILL NOT SUPPORT PRECIP DEVELOPMENT WITH THIS FORCING. DID LEAVE SOME SLIGHT POPS IN NORTHWEST ZONES TUESDAY NIGHT SINCE MOISTURE COULD GET SOMEWHAT DEEPER BY THAT TIME THERE. WENT WITH GFS POPS FOR WEDNESDAY...BUT UPPED THEM SOME 10 TO 15 POINT WEDNESDAY NIGHT WHEN MAIN IMPACT FROM THE SYSTEM LOOKS TO ARRIVE. PAST WEDNESDAY NIGHT I TRIMMED BACK POPS SOME THURSDAY THROUGH SATURDAY WITH RESPECT TO THE HEDGING TOWARD THE EURO MODEL THAT I MENTIONED ABOVE. /BB/ && .AVIATION...LIFR CONDITIONS DUE TO VISIBILITY RESTRICTIONS WAS BEING REPORTED AT KTVR THIS MORNING...BUT ONLY A BRIEF PERIOD OF MVFR CONDITIONS AROUND 12Z IS EXPECTED ELSEWHERE. VFR CONDITIONS WILL RESUME AREAWIDE BY 15Z AND PREVAIL THROUGH 06Z SUN. SOME SPOTTY MVFR CONDITIONS DUE TO VISIBILITY RESTRICTIONS WILL BE POSSIBLE 10-13Z SUNDAY. /22/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 80 53 80 57 / 0 0 0 2 MERIDIAN 78 50 80 51 / 0 0 0 0 VICKSBURG 81 53 82 59 / 0 0 0 6 HATTIESBURG 82 53 81 54 / 0 0 0 0 NATCHEZ 79 55 79 59 / 0 0 0 3 GREENVILLE 80 55 80 60 / 0 0 0 9 GREENWOOD 80 54 80 57 / 0 0 0 8 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ SHORT TERM:22 LONG TERM: 50 ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 315 PM CDT SAT APR 21 2007 .DISCUSSION... STRONG SOUTHERLY SFC WINDS CONTINUE THIS AFTERNOON WITH A HANDFUL OF AWOS/ASOS STATIONS MEETING ADVISORY CRITERIA AS OF PUBLISHING TIME BUT EXPECT MORE SITES TO REACH CRITERIA LATE THIS AFTERNOON/EARLY THIS EVENING. EXPIRATION TIME ON WIND ADVISORY AT 7 PM MAY BE A FEW HOURS TOO EARLY...HOWEVER WILL JUST KEEP IT AS IS AND IF OBS ARE EXCEEDING CRITERIA AT THIS TIME...NEXT SHIFT CAN TAKE ANOTHER LOOK AT THE HEADLINE. FOCUS OVER NEXT 24 HOURS WILL BE COLD CORE UPPER LOW CURRENTLY OVER FOUR CORNERS REGION THAT WILL MOVE NEWD OVERNIGHT AND SLIDE OVER THE TOP OF THE FORECAST AREA SUN AFTERNOON. LATEST SUBJECTIVE SFC ANALYSIS SHOWS DEEPENING LOW PRES CENTERED OVR SERN CO WITH STRONG DRYLINE EXTENDING SWWD AND QUASI-STATIONARY FRONTAL BOUNDARY EXTENDING NEWD FM THE SFC LOW THRU FAR SWRN NEB AND INTO NCTNRL NEB AND CNTRL SD. MID TO UPPER 50S SFC DEWPOINTS COVER MUCH OF THE AIRMASS AHEAD OF THIS BOUNDARY...AS FAR EAST AS WRN IA. CONVECTION IS EXPECTED TO FIRE ALONG DRY LINE LATE THIS AFTERNOON/EARLY EVENING AND ALSO ALONG THE NEWD EXTENDING BOUNDARY...ONCE STRONG CAP EVIDENT ON LBF 18Z SOUNDING WEAKENS. A SERIES OF WEAK WAVES ARE FORECAST TO MOVE ALONG THIS BOUNDARY OVERNIGHT TO KEEP CONVECTION ONGOING AS IT SLOWLY MOVES EWD. QUESTION REMAINS AT HOW FAR EAST THE CONVECTION WILL REACH IF IT INDEED BOWS OUT AS FORECAST. SREF SPAGHETTI PLOTS AND 4KM NMM WRF SHOW THIS ACTIVITY WEAKENING SIGNIFICANTLY AS IT SPREADS INTO ERN NEB LATE TONIGHT. NOT EXPECTING ANY SVR TSTMS OVERNIGHT...BUT LIKELY SOME REMNANT SHOWERS AND ISOLATED TSTMS PASSING ON THROUGH. BY 12Z SUN...SHOWERS AND ISOLATED TSTMS WILL LIKELY BE ONGOING ALONG THE FRONTAL BOUNDARY AT THIS TIME ACROSS MUCH OF NWRN SECTIONS OF THE FORECAST AREA. APPROACHING SYSTEM SHOULD BE FAIRLY VERTICALLY STACKED AS SFC LOW MOVES ACROSS NWRN KS WITH 500MB COLD CORE LOW LAGGING SLIGHTLY BEHIND. 12Z RUC SEEMS TO HAVE A GOOD HANDLE ON CONCEPTUAL MODEL AND HAVE FOLLOWED MORE CLOSELY TO IT. SEVERE WEATHER POSSIBILITY EXISTS FROM BASICALLY LATE SUNDAY MORNING THRU THE AFTERNOON HOURS AS MUCAPE VALUES APPROACH 1000 J/KG BY THE LATE MORNING HOURS...MID LEVEL LAPSE RATES STEEPEN AS UPPER LOW APPROACHES AND BULK SHEER VALUES FORECAST AROUND 40-50KTS. ALSO...WITH -20C 500MB LOW CORE SLIDING DIRECTLY OVERHEAD EARLY AFTERNOON...CANNOT RULE OUT MINI SUPERCELL EVENT FOR THE LATE MORNING/EARLY AFTERNOON HOURS. ACTIVITY SHOULD SUBSIDE BY LATE AFTERNOON/EARLY EVENING AS SYSTEM MOVES INTO NRN IA BY 03Z. MONDAY LOOKS FAIRLY QUIET EARLY IN THE DAY WITH SHORTWAVE RIDGING AND SFC HIGH PRESSURE SLIDING OVER THE AREA. UPSTREAM...LEE CYCLONE DEVELOPS ACROSS CO AHEAD OF NEXT UPPER LOW DIGGING ACROSS THE DESERT SOUTHWEST. THIS PUSHES A WARM FRONT NORTH ACROSS KANSAS AND INTO SRN NEB LATE IN THE EVENING. MODERATE INSTABILITY AND A STRENGTHENING LOW LEVEL JET SHOULD HELP FEED ELEVATED CONVECTION ACROSS KANSAS AND SPREAD IT NWD AS 850MB FRONT SLIDES NWD INTO NEB OVERNIGHT. VERTICALLY STACKED LOW WL MOVE INTO WRN KS LATE MONDAY NIGHT AND ACROSS KANSAS THROUGHOUT THE DAY TUESDAY LEAVING 850MB FRONTAL BOUNDARY TO BISECT THE AREA THRU TUESDAY. SFC FNT ALSO NUDGES INTO FAR SERN CORNER OF NEB ON TUESDAY. EXPECT CONVECTION TO CONTINUE THROUGHOUT MUCH OF THE DAY ACROSS THE FORECAST AREA. BY LATE TUESDAY NIGHT...FORECAST AREA IS ON THE NORTH SIDE OF THE LOW AND SO HAVE TRANSITIONED OVER TO JUST RAIN SHOWERS AS REGION LIES IN DEFORMATION AREA. COULD SEE SOME HEAVY RAINFALL AMOUNTS. LONG RANGE ENSEMBLES COMING TO A CLOSER AGREEMENT THAT THERE WILL BE A MID LEVEL TROF ACROSS THE CENTRAL US BY LATE NEXT FRIDAY OR SATURDAY. HAVE ADDED A CHANCE POP IN FOR THIS. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR NEZ011-012-015>018- 030>034-042>045-050>053-065>068-078-088>090. IA...WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR IAZ043-055-056-069. && $$ GRIFFIS ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 322 AM CDT SAT APR 21 2007 .DISCUSSION... EASTERN EDGE OF THE CONVECTION LIFTING NWD ACROSS NORTHERN NEBRASKA HAD WEAKENED AS IT MOVED ACROSS NWRN CWA EARLY THIS MORNING WITH THE ACTIVITY EXPECTED TO BE N OF THE CWA BY 12Z. THUS WILL RUN A DRY FORECAST FOR TODAY. LOW LEVEL JET FEEDING ACTIVITY AT 07Z WAS 60 KTS PLUS ON AVAILABLE NEBRASKA PROFILERS...ALTHOUGH WINDS FORECAST TO SUBSIDE THROUGH MIDDAY BEFORE INCREASING AGAIN BY THIS EVENING. SINCE 850 MB WINDS ARE FORECAST TO BE A BIT STRONGER THAN YDA...WHICH SAW A FEW LOCATIONS TOUCH WIND ADVSRY CRITERIA...STRONG MIXING AGAIN TODAY SHOULD BRING EVEN STRONGER WINDS. THUS...ISSUED A WIND ADVSRY FOR THIS AFTERNOON ALL BUT FAR SERN ZONES WHERE WINDS WERE JUST A BIT LIGHTER TILL 00Z. WITH LOW LVL JET CRANKING UP AGAIN TNGT...ADVSRY MAY NEED EXTENDING A BIT INTO THE EVENING IF SFC DOESN/T COOL ENOUGH PROVIDING A WEAK INVERSION. ALSO RAISED MOST TEMPS A FEW DEGREES DUE TO MILD START AND BASED HOW WARM IT GOT YDA. EXPECT CONVECTION TO AGAIN FIRE THIS AFTN NEAR DRY-LINE WRN NEBRASKA WITH ACTIVITY EXPECTED TO SHIFT FARTHER EAST BY SUNDAY MORNING. THUS SPREAD LIKELYS OVER WRN 2/3RDS IN 06Z-12Z PD. ALTHOUGH SURFACE BASED OR MIXED LAYER CAPE MODEST/WEAK BY 12Z SUN...LOW LEVEL JET WILL BE STRONG AND UPPER DYNAMICS DECENT AS UPPER LOW SHOULD BE MOVING ACROSS WRN KS BY THEN. THUS SOME SEVERE THREAT WILL LIKELY CONTINUE INTO SUNDAY MORNING WRN ZONES...AND POSSIBLY FARTHER EAST SUNDAY MORNING. WATER VAPOR IMAGERY SHOWED UPPER LOW STARTING TO TURN EWD NEAR NRN BAJA CALIFORNIA AS OF 08Z...PERHAPS A BIT SLOWER THAN 00Z GFS BASED ON LATEST RUC INITIALIZATION. HOW FAST UPPER LOW LIFTS OUT STILL SOMEWHAT IN QUESTION WITH UKMET/ECMWF AND CANADIAN A BIT SLOWER THAN AMERICAN MODELS. WILL CONTINUE TO LEAN TOWARD A SLIGHTLY SLOWER SOLUTION...WHICH COULD ALLOW READINGS SUNDAY TO REACH OR EXCEED 70 AS FAR NW A LNK TO OMA LINE WITH STRONG TO SEVERE CONVECTION REDEVELOPING...IF IT EVEN SUBSIDES...IN THE AFTN NEAR AND EAST OF THE MO RIVER. ACTIVITY SHOULD QUICKLY MOVE EWD THOUGH BY EARLY EVENING WITH A DRY FORECAST THEN THROUGH MON AFTN. DID INCREASE POPS MONDAY NIGHT INTO THE TUESDAY NIGHT PERIOD AS DECENT AGREEMENT AMONG MODELS WITH NEXT UPPER LOW LIFTING A WARM FRONT TOWARD AND POSSIBLY INTO SRN ZONES. NOTICED 00Z ECMWF AND GFS WERE MORE PROGRESSIVE WITH THIS NEXT UPPER LOW/TROUGH AND IF THIS TREND WOULD CONTINUE...POPS MAY NEED LOWERING/DROPPED IN WED NGT/THU PD IN FUTURE FORECASTS. MADE LITTLE/NO TEMP CHANGES TO MONDAY AND BEYOND. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM CDT THIS EVENING FOR NEZ011-012-015>018-030>034-042>045-050>053-065>068-078- 088>090. IA...WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM CDT THIS EVENING FOR IAZ043-055-056-069. && $$ CHERMOK ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HASTINGS NE 258 PM CDT FRI APR 20 2007 .SHORT TERM...PAST MORNING UPPER AIR DATA IN COMBINATION WITH LATEST WATER VAPOR IMAGERY REVEALS A STRONG WAVE DIGGING INTO THE SOUTHWEST CONUS WHILE A RIDGE IS SEEN STRETCHING FROM THE GREAT LAKES INTO THE LOWER MS RIVER VALLEY. THIS IS LEAVING THE CENTRAL PLAINS UNDER AN ACTIVE SOUTHWEST FLOW REGIME ALOFT ALTHOUGH SOME WEAK SHORT WAVE RIDGING IS CURRENTLY DOMINATING THE AREA. CURRENT OBJECTIVE SURFACE ANALYSIS SHOWS A DEEPENING LEE TROUGH ALONG THE FRONT RANGE REGION OF COLORADO WHILE A WEAK WARM FRONT IS SHOWN LIFTING SLOWLY NORTH INTO THE DAKOTAS WHICH HAS TRIGGERED SOME ELEVATED CONVECTION OVER THAT AREA. MAIN FEATURE OF NOTE ACROSS THE AREA IS A LARGE DECK OF STRATUS STRETCHING FROM NORTHERN OK ACROSS CENTRAL SECTION OF KANSAS AND NEBRASKA INTO SOUTH DAKOTA. THIS STRATUS HAS CREATED A DECENT DIFFERENTIAL HEATING BOUNDARY THIS AFTERNOON. MAIN QUESTION AS THE AREA HEADS INTO TONIGHT IS IF ANY CONVECTION COULD POTENTIAL FIRE ALONG THE AFOREMENTIONED DIFFERENTIAL HEATING BOUNDARY. QUICK EXAMINATION OF VIS SATELLITE IMAGERY REVEALS LITTLE SIGN OF DEEPER CONVECTION ATTEMPTING TO DEVELOP WITH RUC LOW LEVEL LAPSE RATES AND CIN VALUES STILL INDICATING A STRONG CAP. AN ISOLATED CHANCE MAY STILL EXIST NORTH OF A BEAVER CITY TO GREELEY LINE...BUT DECIDED TO REMOVE CHANCE OF THUNDERSTORMS OVER REMAINING AREA. LATE SATURDAY INTO SATURDAY NIGHT CONTINUE TO LOOK ACTIVE ACROSS THE PLAINS AS THE SOUTHWEST CONUS UPPER WAVE EJECTS NORTHEAST INTO THE CENTRAL PLAINS. THIS WAVE WILL PUSH A DRYLINE EAST INTO THE HIGH PLAINS BY MID TO LATE AFTERNOON TOMORROW WITH STRONG TO SEVERE CONVECTION DEVELOPING RAPIDLY ALONG AND EAST OF THE BOUNDARY. THIS WILL LEAVE MOST OF NORTH CENTRAL KANSAS INTO CENTRAL NEBRASKA FAR ENOUGH EAST ON SATURDAY THAT DRY CONDITIONS SHOULD PREVAIL UNTIL SATURDAY EVENING. HOWEVER...IT APPEARS AS THOUGH ANY DISCRETE CONVECTION OVER THE HIGH PLAINS DURING THE AFTERNOON TO EARLY EVENING WILL CONGEAL INTO A LINEAR MCS. WITH DEEP LAYER SHEAR IN EXCESS OF 45 KTS AND LINE SEGMENT MOTION POTENTIALLY IN EXCESS 40 KTS...CONCERNED WESTERN HALF OF CWA MIGHT SEE NASTY BOWING SEGMENTS WITH STRONG DAMAGING WINDS DURING THE EVENING. SEVERE THREAT SHOULD START TO FADE DURING THE OVERNIGHT HOURS AS THE MAIN UPPER SYSTEM AND ASSOCIATED DEFORMATION ZONE SLIDE INTO THE PLAINS. THIS MAY SET THE STAGE FOR SOME WIDESPREAD HEAVY RAIN ACROSS THE AREA. NOT CONCERNED WITH FLOODING AT THIS POINT...BUT CANNOT RULE OUT SOME NUISANCE ISSUES. .LONG TERM...12Z SUNDAY THROUGH FRIDAY. MAIN FORECAST CONCERNS WILL BE WHEN PRECIPITATION WILL END ON SUNDAY...PRECIPITATION EXPECTED WITH ANOTHER WAVE FROM MONDAY THROUGH WEDNESDAY AND TEMPERATURES THROUGH THE PERIOD. AN UPPER LOW PRESSURE SYSTEM CONTINUES TO MOVE THROUGH THE CENTRAL PLAINS AND INTO THE GREAT LAKES ON SUNDAY. WITH THE UPPER LOW MOVING OUT OF THE AREA THUNDERSTORMS SHOULD COME TO AN END SOMETIME ON SUNDAY. EXPECT THAT THE SOUTHWEST COULD SEE AN END TO THE PRECIPITATION DURING THE MORNING AND EXPECT THAT THE PRECIPITATION WILL END FOR THE REMAINDER OF THE FORECAST AREA BY EVENING. ONCE THE LOW MOVES OUT THE MOISTURE DECREASES. IN ADDITION...A WEAK SURFACE HIGH PRESSURE SYSTEM MOVES IN TO THE REGION. DO NOT EXPECT THAT IT WILL COMPLETELY CLEAR SKIES...BUT IT SHOULD BECOME PARTLY CLOUDY. THE NEXT UPPER LEVEL LOW WILL START TO AFFECT THE REGION MONDAY. AS THE SURFACE LOW DEVELOPS IN THE LEE OF THE ROCKIES THE SOUTH WINDS WILL ALLOW MOISTURE TO STREAM INTO THE AREA. THEN AS THE FIRST WAVES START TO SLIDE INTO THE REGION...THERE IS A CHANCE OF THUNDERSTORMS MONDAY AFTERNOON IN THE SOUTHWEST AND SPREADING ACROSS THE AREA MONDAY EVENING. AS THE UPPER LOW MOVES INTO THE REGION AND THE SURFACE LOW DRIFTS TO THE EAST MOISTURE IS STREAMING INTO THE AREA. AS THE UPPER LOW MOVES ACROSS THE AREA THUNDERSTORMS WILL LIKELY DIMINISH...BUT SHOWERS ARE STILL POSSIBLE UNTIL THE LOW MOVES FAR ENOUGH EAST WEDNESDAY NIGHT. TEMPERATURES SHOULD REMAIN WARM SUNDAY AND MONDAY AHEAD OF THE SURFACE LOW PRESSURE SYSTEM. THEN TUESDAY THROUGH THURSDAY...WITH THE CLOUDS AND PRECIPITATION AROUND EXPECT IT TO BE A BIT HARDER TO WARM AS MUCH SO HAVE COOLER TEMPERATURES. BUT BY FRIDAY WITH PRECIPITATION GONE AND SOME SUN...TEMPERATURES SHOULD START TO WARM UP AGAIN. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 314 AM CDT FRI APR 20 2007 .DISCUSSION... THUNDERSTORM CHANCES INTO SUNDAY MAIN FORECAST CONCERN. HOW FAST UPPER LOW STILL DIGGING SOUTH ALONG THE WRN CA COAST EJECTS ACROSS THE PLAINS WILL PLAY A LARGE ROLE IN TIMING AND POSSIBLE STORM STRUCTURE. OPERATIONAL MODEL SELECTION SOMEWHAT QUESTIONABLE AS 00Z NAM LACKED CANADIAN UA DATA...ALTHOUGH PROBABLY NOT AS CRITICAL WITH PACIFIC SYSTEM...AND GFS WAS FASTER THAN OTHER OPERATIONAL MODELS PLUS ITS OWN ENSEMBLE MEAN. SHORT TERM...TODAY AND TONIGHT. STLT SHOWED LEAD UPPER LOW LIFTING INTO NERN MT/NWRN ND VCNTY WITH A SHEARED VORT LOBE EXTDG INTO NERN NEBR. POSSIBLY ASSOCD WITH LOBE...ISOLD CONVECTION HAS DEVELOPED IN CLOUD FIELD NW OF LNK/OMA SINCE 0630Z AIDED BY 850 MB THETA E ADVCTN. LATEST RUC SHIFTS THIS ADVCTN NWRD THRU 18Z AS 850 MB WINDS BACK AND STRENGTHEN SLIGHTLY. OTHER CLOUD ELEMENTS APPEARED CELLULAR IN NATURE VIA STLT OVR WRN IA AND WSW OF LNK. THUS WILL CARRY SMALL POPS MOST ZONES THIS MORNING. APPEARS CLOUDS SHOULD DISPT ENOUGH THIS AFTN TO ALLOW MIXING TO NEAR 850 MB AND GUIDANCE/PREV FORECAST LOOKED GOOD. LEFT IN SMALL AFTN POPS FAR SW. THERE MAY NOT BE ENOUGH TO FOCUS ACTIVITY THERE...BUT IT WL BE ON ERN EDGE OF INSTABILITY AXIS AS MOISTURE BEGINS RETURNING NWRD TWD SOME SORT OF BOUNDARY/DRYLINE THAT WL BE ATTEMPTING TO LIFT NWD ACRS WRN NEBRASKA. FOR TNGT...AS LOW LVL JET STRENGTHENS AND VEERS A BIT OVERNIGHT...850 MB THETA E ADVCTN DVLPS OVR FCST AREA. THUS LEFT IN SMALL POPS ALL BUT FAR SERN ZONES EVEN THOUGH NO OTHER APPARENT FOCUS. WARM AND WINDY CONDITIONS LOOK LIKELY ON SATURDAY AS UPPER LOW APPROACHES. NO BIG CHANGES TO TEMPS/WINDS. FOR SAT NGT/SUNDAY KEPT FORECAST BASED ON A SLOWER EJECTION OF TROUGH/LOW SINCE IT WAS BACKED BY 00Z CANADIAN/ECMWF/NAM AND GFS ENSEMBLE MEAN. THUS DECREASED POPS SLIGHTLY SAT NGT ERN ZONES AS SAT AFTN/EVENING CONVECTION THAT DVLPS SHOULD TEND TO MOVE MORE N THAN E. HOWEVER...PCPN CHCS WILL BE INCREASING SUNDAY AS UPPER LOW OR OPENING UPPER TROUGH LIFTS ACROSS THE CWA. ATTM APPEARS SYSTEM WILL BE COMING ACROSS JUST SLOWLY ENOUGH TO ALLOW DECENT HEATING ERN ZONES ENHANCING SEVERE THREAT BOTH NEAR TRACK OF UPPER SYSTEM AND ALONG TRAILING CDFNT. MADE LTL CHANGES TO REST OF FORECAST. MONDAY APPEARS DRY IN ADVANCE OF NEXT SYSTEM...WHICH COULD POSSIBLY LIFT A WARM FRONT INTO SRN ZONES IF LATEST ECMWF/GFS ARE RIGHT. THUS IF THAT TREND CONTINUES ON LATEST MODEL RUNS...TEMPS MAY NEED TO BE RAISED SOME AREAS ON TUESDAY. WED/THU ARE DEPENDANT ON WHETHER UPPER LOW CUTS OFF TO OUR S OR LIFTS AND STALLS OVER US. TOO MANY UNCERTAINTIES TO MAKE SIGNIFICANT CHANGES THIS MORNING. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ CHERMOK ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ALBUQUERQUE NM 232 PM MDT SAT APR 21 2007 .DISCUSSION... CURRENT FORECAST PACKAGE PRETTY MUCH GOING AS EXPECTED WITH SURFACE OBSERVATIONS AND SATELLITE IMAGERY SHOWING MAIN UPPER LEVEL LOW CORE ENTERING CWFA. MUCH OF THE ACTIVITY THROUGH THE REST OF THE AFTERNOON INTO THE EVENING WILL BE A COMBINATION OF SYNOPTICALLY AND CONVECTIVELY DRIVEN. LOOK FOR A LOT OF THE ACTIVITY TO DIE DOWN TOWARDS SUNSET ACROSS MOST OF THE FORECAST AREA WITH SOME RESIDUAL DYNAMICS ACROSS THE NORTH CENTRAL MOUNTAINS AND PERHAPS FAR NORTHEAST PLAINS DEPENDING ON DRY LINE ACTION. WILL HOLD SERVE ON THE WIND ADVISORY AND LET IT GO THROUGH 8 PM. SIERRA BLANCA AND AN OBSERVER HAS ALREADY VERIFIED THE HIGH WIND WARNING IN LINCOLN COUNTY HOWEVER WINDS HAVE ABATED SOMEWHAT THERE. SUSPECT ANOTHER BURST WITH THE BL/700MB WIND FRONTAL PASSAGE SO WILL LET THAT CONTINUE ALTHOUGH WILL BE LIMITED. A COUPLE OF OTHER OBSERVATION SITES TO THE LEE OF THE CENTRAL MOUNTAINS COULD ALSO HIT HIGH WIND WITH THE FROPA BUT NOT AS MUCH CONFIDENCE. CONVECTIVE SHOWER ACTIVITY WILL TEND TO MUDDLE UP ADVISORY AND HIGH WIND WARNING SPEEDS. PRETTY MUCH CONTINUED WITH INHERITED POP PACKAGE FOR TONIGHT WITH MOST OF THE ACTIVITY DYING DOWN BETWEEN 6 TO 8 PM. ALL ACTIVITY DISSIPATED AFTER MIDNIGHT. LESS CONFIDENCE FOR FOG DEVELOPMENT AFTER THE DEPARTING LOW ACROSS THE NC MOUNTAINS SO WILL LEAVE IT OUT. EVENING SHIFT CAN RELOOK AT THAT...DEPENDING ON HOW MUCH PRECIPITATION ENDS UP FALLING. LASTLY...SEVERE WEATHER MOST PROBABLE ACROSS UNION COUNTY AS DRY LINE MIXES EASTWARD. IT APPEARS THAT THE NAM/RUC HAVE A BETTER HANDLE ON THE MSLP SURFACE LOW THAN THE GFS BUT THREAT WILL BE QUICK TO END EITHER LATE THIS AFTERNOON OR EARLY EVENING AS THE UPPER LOW TRUCKS NORTHEASTWARD. WATCH WILL BE POSSIBLE THIS AFTERNOON ACROSS THE FAR NORTHEAST. SUNDAY WILL BE AN IN BETWEEN DAY BEFORE ANOTHER SYSTEM APPROACHES THE AREA LATER SUNDAY INTO THE OVERNIGHT HOURS. LOOK FOR HIGHER CLOUDS TO ADVECT IN ACROSS THE NORTHWEST AS WELL AS SOUTHEAST AREAS LATER SUNDAY AND SUNDAY NIGHT. ADJUSTED TEMPS BOTH PERIODS ACCORDINGLY. ESPECIALLY OVERNIGHT LOWS WHERE TEMPS WILL BE ARTIFICIALLY HIGH DUE TO CLOUD COVER AND INCREASING WINDS ALOFT. BOTH NAM AND GFS PRETTY MUCH IN AGREEMENT WITH TIMING AND SYSTEM TRACK FOR MONDAY AND TUESDAY. BUMPED UP WINDS ACROSS SOUTHERN AND EASTERN AREAS ON MONDAY. DIDNT REALLY ADJUST THE POP OR WX FIELD ALL THAT MUCH AS INHERITED PACKAGE LOOKED GOOD. CERTAINLY SOME DRY SLOT CONSIDERATIONS ACROSS THE SOUTH WITH LOW LEVEL HUMIDITIES A PROBLEM FOR HIGHER QPF AMOUNTS BOTH DAYS. && .PRELIMINARY POINT TEMPS/POPS... FARMINGTON...................... 30 69 44 60 / 0 0 5 30 GALLUP.......................... 23 66 38 59 / 0 0 0 30 GRANTS.......................... 25 68 36 63 / 0 0 0 20 GLENWOOD........................ 37 78 45 73 / 0 0 0 5 CHAMA........................... 16 56 33 50 / 20 0 5 30 LOS ALAMOS...................... 24 67 34 63 / 0 0 0 20 RED RIVER....................... 22 52 34 49 / 20 0 0 20 TAOS............................ 23 65 35 62 / 10 0 0 20 SANTA FE........................ 26 68 35 65 / 5 0 0 10 SANTA FE AIRPORT................ 32 70 41 67 / 0 0 0 10 ESPANOLA........................ 32 73 43 70 / 0 0 0 20 ALBUQUERQUE HEIGHTS............. 39 73 50 72 / 5 0 0 10 ALBUQUERQUE VALLEY.............. 40 75 50 73 / 5 0 0 10 ALBUQUERQUE FOOTHILLS........... 36 72 47 70 / 5 0 0 10 ALBUQUERQUE WEST MESA........... 39 74 49 71 / 5 0 0 10 SOCORRO......................... 41 76 51 76 / 0 0 0 10 SANDIA PARK/CEDAR CREST......... 32 68 44 68 / 5 0 0 10 MORIARTY/ESTANCIA............... 34 69 48 69 / 0 0 0 10 CARRIZOZO....................... 38 71 53 73 / 0 0 0 5 RUIDOSO......................... 39 63 50 63 / 0 0 0 5 RATON........................... 30 71 37 70 / 10 0 0 10 LAS VEGAS....................... 33 69 41 66 / 0 0 0 5 ROY............................. 39 72 50 72 / 5 0 0 5 CLAYTON......................... 40 74 47 77 / 20 0 0 5 SANTA ROSA...................... 43 77 52 79 / 5 0 0 5 TUCUMCARI....................... 42 78 49 82 / 10 0 0 5 FORT SUMNER..................... 43 79 49 82 / 5 0 0 5 CLOVIS.......................... 43 78 53 80 / 5 0 0 5 PORTALES........................ 41 79 52 82 / 5 0 0 5 ROSWELL......................... 44 81 53 84 / 5 0 0 5 && .ABQ WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 8 PM MDT THIS EVENING FOR THE FOLLOWING ZONES... NMZ004>007-009>013-015-018>021-026. HIGH WIND WARNING UNTIL 8 PM MDT THIS EVENING FOR THE FOLLOWING ZONES...NMZ016-017. && $$ 50 nm AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BINGHAMTON NY 120 AM EDT FRI APR 20 2007 .AVIATION /200600Z-210600Z/... VFR CONDITIONS WILL PERSIST THROUGH THE TAF PERIOD WITH CLEAR OR NEARLY CLEAR SKIES AT ALL SITES. FOG NOT EXPECTED TONIGHT AS DEWPOINT DEPRESSIONS ARE STILL PRETTY HEALTHY AND DEWPOINTS HAVE TRENDED DOWN A LITTLE OVER THE PAST FEW HOURS. LGT/VAR WINDS OVERNIGHT TONIGHT WILL BECOME NORTH-NORTHWESTERLY THIS MORNING AROUND 10KTS AND CONTINUE THROUGH SUNSET...WHEN THEY WILL DIMINISH TO 5KTS OR LESS ONCE AGAIN. AN EXTENDED PERIOD OF VERY GOOD FLYING WEATHER IS IN STORE. && PREV DISCUSSION... /ISSUED 209 PM EDT THU APR 19 2007/ SHORT TERM /TONIGHT THROUGH SUNDAY/... GLOBAL MODELS CONTINUE TO BE IN GOOD AGREEMENT THROUGH SUNDAY TAKING THE OMEGA BLOCK THAT IS OVER THE CENTRAL PORTION OF THE NORTH AMERICAN CONTINENT AND PUSHING IT EASTWARD. AT THE SAME TIME...THE RIDGE ASSOCIATED WITH THIS BLOCK WILL FLATTEN. WE WILL REMAIN EAST OF THE MID LEVEL/SURFACE RIDGE AXIS THROUGH SATURDAY NIGHT...WITH DRY NORTHERLY FLOW OVER THE CWA. MINOR AMOUNTS OF CLOUD COVER THROUGH THE PERIOD WILL BE GOVERNED BY SOME WEAK MID LEVEL IMPULSES THAT WILL ROTATE THROUGH THE AREA. WITH THE SFC RIDGE NEARING THE AREA BY THE END OF THE WEEKEND...EXPECT TEMPS TO MOVE WELL /10F/ ABOVE SEASONAL NORMS BY THE SATURDAY-SUNDAY TIMEFRAME. THIS EVENING...THE RUC AND NAM PROFILES SUGGEST THE ARRIVAL OF ONE LAST WEAK SHORTWAVE FROM THE EAST AROUND OR JUST AFTER 00Z TONIGHT. NAM/RUC RH PROGS SHOW A LITTLE BIT IN THE WAY OF MID LEVEL MOISTURE ASSOCIATED WITH THIS WAVE...MOSTLY IMPACTING OUR SOUTHEASTERN ZONES. WITH 500 HEIGHTS BUILDING THROUGH THE EVENING...CAN`T SEE THIS WAVE DOING ANYTHING MORE THAN DELAYING THE TRANSITION FROM PCLOUDY TO MCLEAR OVER THE SOUTHERN ZONES THIS EVENING. AFTER THIS WAVE DEPARTS...EXPECT A PROLONGED PERIOD OF DRY WEATHER WITH TEMPERATURES CONTINUING TO CLIMB. MODELS BRING A PRETTY STRONG SHORT WAVE RIDGE THROUGH THE AREA ON FRIDAY...ALLOWING FOR A WONDERFUL DAY. BUFKIT PROFILES ARE QUITE DRY WITH A STRONG SUBSIDENCE INVERSION. GOOD MIXING TO 850 WILL TAP ANY WINDS IN THE LOWER LEVELS AND BRING THEM TO THE SURFACE...BUT THE GRADIENT WON`T BE PARTICULARLY IMPRESSIVE...SO NOTHING MORE THAN 20-25MPH GUSTS ARE EXPECTED. T850 RANGES FROM +4-6C IN THE GUIDANCE...WHICH WOULD GIVE HIGHS IN THE L/MID 60S...AND WE`LL LEAN TOWARDS THE WARMER END BASED ON HOW THE MODELS HAVE BEEN PLAYING CATCH UP WITH THE TEMPS OVER THE PAST FEW DAYS. IT APPEARS WE WILL FINALLY GET A CHANCE TO DRY OUT SOME WITH DEW POINTS REMAINING IN THE U20S/L30S THROUGHOUT THE DAY. TONIGHT...MODELS DROP THE DEWPOINTS RAPIDLY WITH OVER-LAND NORTHEASTERLY FLOW. UPSTREAM OBS FROM OUR CANADIAN NEIGHBORS AND EVEN THOSE OVER NEW ENGLAND INDICATE DEWPOINTS DROPPING INTO THE TEENS. THINK THIS STRONG LLEVEL DRYING WILL HOLD OFF UNTIL OVERNIGHT TONIGHT. THIS SHOULD ALLOW TEMPS TO FALL NICELY TONIGHT...PROBABLY COOLER THAN OVER THE PAST FEW NIGHTS. WILL GENERALLY FOLLOW MET GUIDANCE. THESE DRY READINGS...ALONG WITH A LITTLE BIT OF WIND SHOULD KEEP FOG FROM BEING A PROBLEM. THE DRY WEATHER CONTINUES INTO SATURDAY WITH LITTLE CHANGE. RH PROGS SHOW A LITTLE BIT IN THE WAY OF UPPER LEVEL MOISTENING IN THE AFTERNOON AS A WEAK SHORT WAVE ROTATES TOWARDS THE AREA IN THE NORTHWEST FLOW ALOFT. HOWEVER...THE DAY SHOULD BE SUNNY/MSUNNY AND WITH T850 BETWEEN 5-6C HIGHS AROUND U60S TO AROUND 70 LOOK GOOD. ALTHOUGH DEEP MIXING IS AGAIN EXPECTED...WEAKER GRADIENTS WILL LESSEN THE WINDS EVEN MORE...15MPH OR LESS EVEN IN GUSTS. LLEVEL RHS WILL LIKELY BE A LITTLE HIGHER THAN ON FRIDAY AS BOUNDARY LAYER WIND TRAJECTORIES TAKE MORE OF A TRACK OVER THE LAKES. THIS INCREASED LLEVEL MOISTURE SHOULD HELP KEEP LOWS SATURDAY NIGHT A LITTLE WARMER THAN ON FRIDAY NIGHT...PROBABLY JUST ABOVE FREEZING RATHER THAN AT/JUST BELOW. A LOW PRESSURE SYSTEM WILL MOVE EAST SOUTH OF HUDSON BAY ON SUNDAY AS THE EAST COAST RIDGE BEGINS TO FLATTEN. ALTHOUGH WELL NORTH OF THE CWA...SOME UPPER LEVEL CLOUDINESS MAY FILTER IN FROM THE NORTH. HOWEVER...THE DAY WILL STILL TURN OUT MSUNNY. WITH T850 REACHING 6-7C...U60S/L70S ARE LIKELY FOR HIGHS ACROSS THE CWA. WINDS WILL REMAIN QUITE LIGHT AS THE CREST OF THE SURFACE RIDGE MOVES OVER THE AREA. LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... NEXT WEEK WILL START OFF WITH A CONTINUATION OF DRY MILD WEATHER. BY TUESDAY...A COLD FRONT IS EXPECTED TO MOVE ACROSS FROM THE NORTHWEST...ACCOMPANIED BY SOME SHOWERS. AT THIS POINT...THE FRONT LOOKS AS THOUGH IT WILL BE PROGRESSIVE ENOUGH...SO THAT DRIER AND SOMEWHAT COOLER WEATHER SHOULD RETURN FOR WEDNESDAY AND THURSDAY. HYDROLOGY... BAINBRIDGE AND CONKLIN STILL THE PRIMARY SITES OF CONCERN WITH CONKLIN JUST ABOVE FS AND BAINBRIDGE VERY NEAR IT. RIVERS CONTINUE TO BE FED BY SNOWMELT...BUT THIS WILL COME TO AN END SOON. WAVERLY ALSO FORECAST TO COME CLOSE TO FS TOMORROW. HAVE KEPT WARNINGS AS THE ARE ATTM...BUT EXPECT RIVERS TO BEGIN TO FALL ESPECIALLY AS WE MOVE INTO TOMORROW AS THE REMAINING SNOWPACK IS LOST AND WE SEE AN EXTENDED DRY PERIOD. AGAIN...ONLY VERY MINOR FLOODING IS EXPECTED. && .BGM WATCHES/WARNINGS/ADVISORIES... NY...NONE. PA...NONE. && $$ AVIATION...JMA ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 1007 AM CDT SAT APR 21 2007 .UPDATE...SHOWERS/THUNDERSTORMS HAVE DECREASED SIGNIFICANTLY ACROSS THE AREA. EVEN THE AREA OF STORMS ON CENTRAL ND/SD BORDER WHICH SHOWS AN MCV IS QUICKLY SHRINKING IN SIZE AND WEAKENING MORE THAN ONE WOULD EXPECT. HAVE DECREASED PROBABILITY OF STORMS TO CHANCE CATEGORY THROUGHOUT REGION UNTIL NOON AND MOST OF EAST PORTION TIL 3PM. TWO SHORTWAVES OF CONCERN: ONE CURRENTLY AT SOUTHWEST CORNER OF ND WHICH IS KEEPING THE REMAINING SHOWERS GOING AHEAD OF IT...AND ANOTHER NEAR CO/NE/KS STATE JUNCTION. THE FIRST WILL TARGET NORTHEAST ND AND THE LATTER FARTHER SOUTH AND EAST (INTO RED RIVER VALLEY). AN EARLY EXTRAPOLATIVE APPROACH PLACES THE SHORTWAVES INTO THE CWA MUCH LATER THAN RUC INDICATES BUT IS MORE IN LINE WITH CURRENT PROGRESSION OF THE SHOWERS THEMSELVES. BUT AM NOT SURE OF THE TIMING OF THE LOW LEVEL THERMAL FIELD TO DESTABILIZE ENOUGH TO INITIATE STORMS ANYWAY. OTHERWISE NO CHANGES TO GRIDS OR ZONES AND WILL BE KEEPING WATCH FOR SIGNATURES IN SATELLITE AND OBS. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...FLASH FLOOD WATCH FROM 6 PM CDT THIS EVENING THROUGH SUNDAY MORNING FOR NDZ039-049-052-053. MN...FLASH FLOOD WATCH FROM 6 PM CDT THIS EVENING THROUGH SUNDAY MORNING FOR MNZ003-029. && $$ GV nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 350 PM CDT FRI APR 20 2007 .SHORT TERM...INITIALLY SEVERE THUNDERSTORMS IN NORTHEAST SD HAS SLACKENED A BIT BUT ARE BEGINNING TO SPREAD INTO SOUTHEAST ND. THEY ARE MOVING NORTH ON THE NOSE OF 850 MB JET AND BRINGING ELEVATED INSTABILITY WITH IT AND AHEAD OF AN UPPER LEVEL SHORTWAVE. HOWEVER THE JET CORE IS ONLY 35-40 KNOTS ACCORDING TO RUC AND AREA PROFILERS AND WILL LIKELY NOT SUPPORT STRONG THUNDERSTORMS MUCH EARLY THIS EVENING. RUC SHOWS THE JET STRENGTHENING TO 50 KNOTS BY 06Z SOUTH OF WAHPETON BUT 850 MB CAPE IS NORTH OF GFK BY THEN. STILL...THIS ABR REPORTED ALMOST A HALF INCH OF RAIN IN ONE HOUR TO SHOW THE POTENTIAL OF PRECIPITATION APPROACHING THIS WEEKEND. SEVERE POTENTIAL ON SAT REMAINS THOUGH SURFACE DEW POINTS IN THE MID/UPPER 50S ON SAT AND THE LACK OF A STRONG SHORTWAVE MAY LIMIT SURFACE BASED STORMS A BIT. THREAT OF HEAVY RAIN WILL BE LOCALIZED WITH 1.25 INCH OR SO OF PRECIPITABLE WATER BUT A TRAINING LINE OF STORMS MAY PRODUCE MORE. LEANED ON HPC AND NAM QPF MOST BUT 3 DAY QPF ENDED UP BEING SIMILAR TO HPC. NAM PICKED UP ITS PROGRESSION TO MATCH GFS WHILE BACKING OFF A BIT ON QPF AMOUNTS...SO FAVORED NAM OVERALL. .LONG TERM...(TUE-FRI) A SYSTEM CURRENTLY OVER THE ERN PAC OCEAN...AROUND 48N 148W... IS PROGGED TO GENERATE A SHORT WAVE THAT WILL HIT SHORE AROUND SUNDAY IN NRN CA. THIS SYSTEM PROGGED TO DEVELOP OVER CNTRL ROCKIES AND MOVE THROUGH CENTRAL PLAINS MID NEXT WEEK. CURRENT PROGS SHOW MAIN ENERGY WELL SOUTH OF CWA. WHEREAS PREVIOUS RUNS SHOWED A BAND OF H700 FRONTOGENESIS FORCING JUST SOUTH OF THE CWA...THREAT OF PRECIP NOW LOOKS TO BE FURTHER SOUTH. THUS I REMOVED RAIN SHOWERS FROM SOUTHERN TIER COUNTIES FOR LATE MON NIGHT/EARLY TUE. NEXT EVENT OF INTEREST IS FOR THURSDAY NIGHT INTO FRIDAY...WHERE 12Z GFS IS BRINGING A SHORT WAVE ACROSS EXTREME SRN CANADA AND MT/ND. LATEST GFS RUN FASTER THAN THE ECMWF...WHICH SHOWS A SFC RIDGE OVR ERN MN...AND AN UPPER LEVEL RIDGE ALOFT...THURSDAY NIGHT. WAVE SHOWS UP BEST ON ECMWF H700-H850 RH PROG. ECMWF MOVES WAVE INTO CWA FRIDAY MORNING. HPC BLEND SHOWING 70 PERCENT ECMWF SOLUTION...THUS BRING PRECIP INTO CWA ON FRI MORNING. .AVIATION VFR CONDS EARLY IN TAF AND TWEB PERIODS. HOWEVER...AS MOIST AIR CONTINUES TO PUMP INTO CWA FROM THE SOUTH...THREAT OF CONVECTION INCREASES. WORST THREAT WILL BE SOUTH OF KFAR WHERE SPC HAS ISSUED A SEVERE WEATHER WATCH. EXPECT CIGS TO GENERALLY BE VFR OUTSIDE OF TSTMS...AND LOWERING TO 2000 TO 3000 FEET BY MIDNIGHT. NAM12 SHOWING A TIGHT DEWPOINT GRADIENT ALONG A LINE EXTENDING FROM SW OF KBIS TO NE OF KDVL...WITH SFC TROF JUST TO THE EAST OF THIS BOUNDARY. CONSEQUENTLY...TWEB ROUTE FROM KBIS TO KFAR SHOULD SEE STRONGEST CONVECTIVE ACTIVITY. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ GV nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 329 AM EDT SUN APR 22 2007 .SHORT TERM /TODAY THROUGH MONDAY NIGHT/... SHORT TERM CHALLENGES WERE PRIMARILY IN REFINING TEMPERATURES. BROAD AREA OF HIGH PRESSURE CONTINUES TO DOMINATE OVER THE EASTERN CONUS...WITH CLOSEST RADAR ECHOES OF NOTE OVER THE PLAINS STATES. ANOTHER WARM/DRY AFTN...AS HIGH PRESSURE CONTINUES TO SLOWLY DRIFT SE...MOVING OFF CAROLINA COAST THIS AFTN. RAPIDLY RISING HEIGHTS THIS AFTN...AND WARM/DRY RETURN FLOW BY AFTERNOON...SUGGESTS L/M 80S EASILY ATTAINABLE FOR MOST OF CWA...TO AROUND 80 AT IMMEDIATE COAST AND OVER EASTERN SHORE. EXPECTING SEA BREEZE TO AGAIN PLAY A ROLE OVER COASTAL PLAIN THIS AFTN. ONCE AGAIN AGAINST IMMEDIATE COASTLINE WITH VRY LGT SYNOPTIC WNDS THIS AFTN. HV MADE SOME MINOR ADJUSTMENTS OVER THESE LOCATIONS TO REFLECT SLIGHTLY COOLER TEMPS BY MID TO LT AFTERNOON IVOF ORF/CPK/NCZ102. USED MAV/MET BLEND FOR TEMPERATURES THIS AFTN...AND TRENDED TOWARDS COOLER MAV GUIDANCE FOR TONIGHT WITH LTL/ANY DISCERNIBLE CLOUD COVER ALLOWING FOR ANOTHER GOOD RADIATING NGT. ANOTHER WARM/DRY DAY ON TAP FOR MONDAY...WITH M/U 80S LOOKING POSSIBLE FOR PIEDMONT AND CENTRAL VA (L/M 80S AT COAST) WITH ROBUST RETURN FLOW BY MONDAY AFTN. WENT CLOSER TO WARMER MAV GUIDANCE FOR HIGHS ON MONDAY. CLOUDS SLOWLY INCREASE BY MONDAY NGT/ERY TUESDAY AHEAD OF NEXT WEATHER MAKER. && .LONG TERM /TUESDAY THROUGH SATURDAY/... BIGGEST CHALLENGE IN EXTENDED WAS IN TIMING AND DETERMINING PCPN CHANCES FOR MID TO LATE WEEK. STILL GOOD MODEL AGREEMENT THAT FIRST FRONTAL SYSTEM WL REMAIN NORTH OF THE AREA....GENERALLY REMAINING ORIENTED FROM SOUTHERN NEW ENGLAND SOUTH INTO NORTHERN VA AND EXTENDING INTO THE OHIO VLY. 00Z/APR22 GFS DOES BRING BACKDOOR FRONTAL BNDRY A BIT FURTHER SOUTH THAN NAM. HOWEVER DO NOT SEE MUCH IN THE WAY OF FORCING THAT WOULD SUPPORT THIS SOLN ATTM. FOR NOW...WL PUSH FRONT AS FAR SOUTH AS FAR NORTHERN COUNTIES...RESULTING IN MOST OF THE AREA REMAINING DRY...AND REMAINING WITHIN WARM SECTOR. DUE TO THE PROXIMITY OF THE FRONT...WL INCREASE CLD COVER OVER THE NORTH AND KEEP SLIGHT CHANCE POPS FOR RIC-WAL AND NORTH FOR TUES NGT/WED. FUTURE SHIFTS WL BE ABLE TO ADJUST THIS AS NECESSARY. EITHER WAY...IT SHOULD BE NOTED THAT MEAGER AVAILABLE PCPN (PW VALUES REMAIN UNDERWHELMING) AND LACK OF ANY VIABLE CONVERGENCE CONTINUE TO BOLSTER BELIEF THAT ANY PCPN THAT DOES THREATEN THE AREA WL BE LGT AND VERY SMALL IN AREAL COVERAGE. FRONT DRIFTS BACK NORTH WEDNESDAY. AGREE WITH GOING FORECAST THAT A SIZABLE TEMPERATURE GRADIENT COULD EXIST BETWEEN NORTHERN AND SOUTHERN CWA...WITH LINGERING CLOUDINESS AND SCTD SHRAS HOLDING TEMPS BACK A BIT OVER NORTHERN SECTIONS. HOWEVER...KEPT TEMPS A LITTLE WARMER THAN MEX VALUES GIVEN LACK OF MODEL CONTINUITY OF LATE. NEXT...AND MORE LKLY PCPN THREAT COMES WITH A STRONGER FRONTAL PASSAGE THU NGT/FRI. LOW PRESSURE WL DEVELOP OVER THE MO VLY BY THU...TRACKING EASTWARD ALONG THE FRONTAL BOUNDARY. MODEL GUIDANCE CONTINUES TO KEEP BEST SLUG OF MOISTURE NORTH OF THE AREA. NONETHELESS...CONTINUING THE GOING CHC (30) POP FOR SHRAS/TSTMS AS H5 TROF PUSHES THROUGH ERY FRIDAY INTO FRI AFTN LKS GOOD. DRIER WX MOVES IN QUICKLY BEHIND THE FRONTAL BOUNDARY...AS WK HIGH PRESSURE PUSHES IN FROM THE SOUTHWEST. WL LEAVE FRIDAY NGT AND SATURDAY DRY FOR NOW. && .AVIATION /08Z-06Z/... VFR THRU PRD. WNDS BELOW 10 KTS. ONLY A FEW HIGH CLDS XPCTD. && .MARINE... NO FLAGS THRU MON AS HIGH PRS MOVES OFFSHORE. WNDS AOB 15 KTS. SEAS REMAIN IN THE 3-4 FT RANGE DUE TO RESIDUAL SWELL. DATA SUGGESTS OUR TYPICAL NOCTURNAL SPIKE IN SW WNDS MONDAY NIGHT INTO ERLY TUE...BUT WILL HOLD WNDS TO ARND 15 KT ATTM. BKDR FRNT NOW PROGGED TO ENTER NRN HALF OF MARINE AREA LATE TUE...TURNING WNDS INTO A E-SE DRCTN TUE NITE. FRNT THEN PROGGED TO LIFT BACK N AS A WRM FRNT WED...RESULTING IN SW WNDS ONCE AGAIN. && .FIRE WEATHER... LOW RH ONCE AGAIN TODAY. UTILIZED RUC/LOCAL WRF MODIFIED SOUNDING AND TRENDED RH/DEWPOINT WELL BELOW GUIDANCE...GIVEN POOR MODEL PERFORMANCE ON TD OF LATE. HOWEVER...EVEN WITH DRYING FUELS...LGT WNDS SHOULD DIMINISH ANY FIRE WEATHER CONCERNS CONSIDERABLY. EVEN STILL.. WL AGAIN MENTION DRY COND IN FWF...BUT WL HOLD OFF ON ANY STATEMENTS ATTM. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SHORT TERM...MONTEFUSCO LONG TERM...MONTEFUSCO AVIATION...RUSNAK MARINE...RUSNAK FIRE WEATHER...MONTEFUSCO md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 355 AM EDT SUN APR 22 2007 .DISCUSSION... 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR RDG OVER THE GRT LKS BTWN LARGER SCALE TROFS OVER THE W AND IN THE WRN ATLANTIC. CWA DOMINATED BY SW FLOW BTWN HI PRES IN THE MID ATLANTIC STATES AND LO PRES TROF STRETCHING FM THE CNTRL PLAINS INTO MN ON THE ERN FLANK OF WRN TROF. ALTHOUGH 00Z GRB/MPX/APX SDNGS ARE QUITE DRY AND CAPPED...A FEW SHRA/TSRA NOTED OVER OVER THE MN ARROWHEAD AND INTO ERN LK SUP WHERE SHRTWV RUC SHOWS MOVING THRU NRN MN/ADJOINING ONTARIO IS INTERACTING WITH H85 WARM FNT ON THE NRN EDGE OF MID LVL CAPPING MARKED BY H7 TEMP ARND 2C. SKIES MOCLR TO THE S OF WARM FNT DESPITE STEEP H7-5 LAPSE RATES SHOWN ON THE 00Z MPX SDNG ABV H7 WARM NOSE/CAP. MORE WDSPRD CNVCTN HAS BROKEN OUT AS FAR E AS WRN MN ALG WARM FNT IN ADVANCE OF POTENT SHRTWV LIFTING OUT OF THE SRN ROCKIES. OTHER SHRTWVS ROTATING WITHIN WRN TROF ARE LOCATED OVER SRN SASKATCHEWAN AND JUST OFF THE CA COAST. MAIN FCST CONCERNS TDAY REVOLVE ARND DISPOSITION OF ONGOING CNVCTN FM THE MN ARROWHEAD INTO ERN LK SUP AND FIRE WX ISSUES. FOCUS FOR TNGT/MON SHIFTS TO SHRA/TSRA CHCS ASSOCIATED WITH SHRTWV NOW LIFTING OUT OF THE SRN ROCKIES. FOR EARLY THIS MRNG...RUC SHOWS SHRTWV HELPING TO INITIATE CNVCTN ALG H85 WARM FNT MOVING ENE THRU ONTARIO N OF LK SUP. MODEL SHOWS H85-5 QVECTOR CNVGC ASSOCIATED WITH DPVA AND WAD LINGERING OVER ERN LK SUP UNTIL ABOUT 09Z WHEN THE SYS IS PROGGED TO MOVE CLOSER TO JAMES BAY. ANOTHER ROUND OF DEEP LYR H85-3 QVECTOR CNVGC ASSOCIATED WITH ANOTHER SHRTWV PROGGED TO LIFT TOWARD WRN LK SUP BY 12Z. SO EXPECT CNVCTN OVER NE LK SUP TO DIMINISH BY FCST ISSUANCE...BUT WL MAINTAIN MENTION OF SCT TSRA OVER WRN LK SUP THIS MRNG. THIS NEXT SHRTWV FCST TO SLIDE NE INTO ONTARIO AS WELL BEFORE NEXT ROUND OF DEEP LYR H85-3 QVECTOR CNVGC AHEAD OF STRONGER SHRTWV FCST TO REACH IA BY 00Z MON ARRIVES LATER IN THE DAY. NAM/GFS FCST SDNGS INDICATE MID LVLS WL REMAIN SUFFICIENTLY CAPPED THRU MOST OF THE DAY TO KEEP LAND FA DRY EVEN THOUGH SCT SHRA/TSRA WL PERSIST OVER WRN LK SUP ON EDGE OF CAP AND CLOSER TO APRCHG COOL FNT ASSOCIATED WITH SHRTWV NOW IN SASKATCHEWAN. BULK OF MODELS GENERATE SOME LGT QPF OVER THE FAR WRN ZNS BY 00Z MON JUST IN ADVANCE OF THIS COLD FNT. CONSIDERING DRY NATURE OF LLVLS TO THE SW (MIXING TO H8 ON 00Z MPX SDNG WOULD YIELD SFC DWPT ARND 40...DVN SDNG IS EVEN DRIER) AS WELL AS ACYC H85 FLOW IN ADVANCE OF FNT...THINK GUIDANCE MAY BE A BIT TOO AGGRESSIVE AT SPITTING OUT PCPN EVEN OVER THE FAR W BEFORE 00Z AND COLD FROPA... ESPECIALLY SINCE BOTH MODELS PUSH SFC DWPTS INTO THE LOW 50S AT IWD BY 00Z. BUT SINCE GOING FCST HAS CHC POPS OVER THE FAR W AFT 21Z AND MODELS GENERATE SOME QPF...WL MAINTAIN LO CHC POPS FM CMX-IWD. AS FOR FIRE WX CONCERNS...MIXING TO H8-825 ON GFS/NAM FCST SDNGS WOULD SUPPORT HI TEMPS IN THE 75 TO 80 RANGE AWAY FM THE MODERATING INFLUENCE OF LK MI. LOOKING AT THE UPSTREAM MPX/DVN SDNGS...MODELS LOOK TOO AGGRESSIVE AT RETURNING LLVL MSTR AND PUSHING DWPTS AOA 50. IF DWPTS ARE 40 E TO 48 W...EXPECT RH TO DROP AS LO AS 25 TO 30 PCT AGAIN. WITH GUSTY WINDS LIKELY (NAM AND ESPECIALLY THE GFS SHOW MIXED LYR WINDS INCRSG TO 25 TO 35 KT)... FIRE WX PARAMETERS WL APRCH CRITICAL LVLS AGAIN TDAY. FOR TNGT...NAM/GFS DIVERGE ON FCST OF HANDLING OF SHRTWV IN IA AT 00Z MON...WITH GFS SHOWING SHRTWV MOVING TO JUST S OF GRB AT 12 MON WHILE NAM HOLDS SHRTWV BACK OVER NW IL. WITH SUPPORT FM THE MOST CONSISTENT 00Z UKMET (WHICH IS NCEP FVRD MODEL)...WL FOLLOW THE MORE SIMILAR GFS SCENARIO. MEANWHILE... GFS/UKMET FCST SHRTWV IN SASKATCHEWAN THIS PAST EVNG TO MOVE ACRS ONTARIO...WITH ACCOMPANYING SFC COLD FNT MOVING TO ABOUT P53-MNM BY 12Z MON. SINCE THESE SHRTWVS ARE FCST TO REMAIN OUT OF PHASE THRU THE NGT...GFS SHOWS TWO STRIPES OF HEAVIER PCPN. THE FIRST OF THESE IS OVER THE WRN ZNS DURING THE NGT DUE TO MORE SGNFT UPR DVGC IN RRQ OF UPR JET SUPPORTING ONTARIO SHRTWV AS WELL AS SHARP H85-7 FGEN BEHIND THE ASSOCIATED SFC FNT. GFS SHOWS THESE DYNAMICS TENDING TO SHIFT MORE NE DURING THE NGT...SO ITS HEAVIER QPF DOES NOT SPREAD E. THE UKMET ON THE OTHER HAND INDICATES THE SHARPER UPR DVGC/FGEN WL SPREAD FARTHER E...SO IT DRAGS HEAVIER PCPN INTO THE CNTRL ZNS BY 12Z. THE GFS ALSO FCSTS AN AXIS OF HEAVIER QPF ACRS THE SCNTRL ON THE CYC SIDE OF SHRTWV PASSAGE THRU WI AND WHERE INSTABILITY IS A BIT MORE IMPRESSIVE. CONCERNING SVR THREAT...OLD DAY 2 CONVECTIVE OUTLOOK HAD MUCH OF THE W HALF OF THE FA IN SLGT RISK. THINK BEST CHC OF SVR TSRA WOULD BE IN THE 00Z-06Z TIME FRAME ALONG AND JUST BEHIND COLD FROPA OVER THE W WHEN FCST 0-6KM BULK SHEAR NEAR 50KT WOULD BE BETTER PHASED WITH LOWER SSI FCST IN THE -2C TO -3C RANGE/STEEPER SFC-H8 LAPSE RATES THAT WOULD ALLOW MORE EFFICIENT TRANSFER OF GUSTY WINDS TO THE SFC. HOWEVER... MODIFIED GFS FCS SDNG FOR IWD AT 00Z FOR SFC T/TD 73/50 AND SOMEWHAT COOLER MID LVL TEMPS THAN EXPLICITLY FCST BY GFS YIELDS MO MORE THAN A FEW HUNDRED J/KG OF SFC BASED CAPE. ALTHOUGH WBZ FCST AT A FVRBL 9.5K FT...FCST MARGINAL LAPSE RATES WOULD HAVE A DIFFICULT TIME SUPPORTING LARGE HAIL. FCST LAPSE RATES/SHEAR PROGGED TO DIMINISH SGNFTLY AFT 06Z...SO ANY SVR THREAT SHOULD DIMINISH OVERNGT AS THE FNT PUSHES E. NOT SURPRISINGLY...THE NEW DAY1 CONVECTIVE OUTLOOK NO LONGER SHOWS THE FA IN THE SLGT RISK. SINCE NCEP INDICATES THE GFS BECOMES TOO FAST ON MON...TENDED TO FOLLOW THE UKMET FCST FOR FCST PREPARATION. AS PAIR OF SHRTWVS MOVE TO THE E...MODEL FCSTS COLD FROPA AT ERY BY 15Z...WITH LINGERING DEEP MSTR/SHARP H85-7 FGEN CLEARING THAT POINT BY 18Z. WL KEEP LINGERING HIER POPS OVER THE E HALF IN THE MRNG WITH POPS TO THE W DIMINISHING W-E AS COOLER AND DRIER AIR OVERSPREADS THE FA. SINCE UKMET IS SLOW TO LOWER H85 DWPT (SIMILAR TO OTHER MODELS)...SUSPECT THERE WL BE A GOOD AMT OF SC IN THE AFTN OVER AREAS INLAND FM THE STABILIZING INFLUENCE OF LK SUP. MUCH DRIER AIR LOOKS TO ARRIVE LATER IN THE DAY...SO EXPECT CLRG OF THE SC LATER WITH LOWERING SUN ANGLE. MON WL TURN OUT MUCH COOLER WITH UKMET SHOWING H85 TEMP LOWERING TO 2 TO 4C BY 00Z TUE. QUIET AND COOLER WX LOOKS ON TAP MON NGT THRU MOST OF THE REST OF THE WEEK AS CNDN HI PRES BLDS FM THE NW TERRITORIES INTO ONTARIO. NEXT SHRTWV NOW MOVING TOWARD CA LOOKS LIKE IT WL REMAIN WELL TO THE S AS IT MOVES E. JUST MINOR CHGS TO MESH BETTER WITH SURROUNDING OFFICES MADE TO GOING FCST. COORDINATED WITH GRB. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 134 AM EDT SUN APR 22 2007 .AVIATION...STRONG...DRY HIGH PRESSURE TO OUR SE WILL MAINTAIN VFR CONDITIONS THRU THE NEXT 24 HOURS. THIN HIGH CIRRUS (DEBRIS FROM SHOWERS/TSTORMS OVER UPPER MICHIGAN AND NORTHERN WISCONSIN) WILL PASS ACROSS THE AREA EARLY THIS MORNING. WILL MAINTAIN THE LOW LEVEL WIND SHEAR AT ALL TAF SITES DUE TO INCREASING WIND SPEEDS JUST ABOVE THE SURFACE TONIGHT AS HIGH PRESSURE MOVES FURTHER EAST...AWAY FROM THE REGION. HOWEVER...STABLE AIR AT THE SURFACE WILL KEEP THESE WINDS FROM REACHING GROUND LEVEL UNTIL A FEW HOURS AFTER SUNRISE TODAY. A STORM SYSTEM OVER THE SW UNITED STATES CURRENTLY WILL TRACK TOWARD THE GREAT LAKES TOMORROW NIGHT. MOISTURE WILL INCREASE AHEAD OF THE SYSTEM...BUT VFR CONDITIONS ARE EXPECTED TO HOLD THROUGH THE TAF PERIOD WITH PRECIP ARRIVING AFTER 06Z TOMORROW. MPC && .UPDATE...ISSUED AT 1008 PM EDT SAT APR 21 LATEST RUC AND SURFACE ANALYSIS AND IR/WV/RADAR IMAGERY SHOW SURFACE HIGH PRESSURE MIGRATING EAST OVER THE SOUTHEASTERN GREAT LAKES WHILE THE 500MB RIDGE AXIS IS DIRECTLY OVERHEAD. TO THE WEST...A BROAD SURFACE LOW PRESSURE LIES OVER THE CENTRAL PLAINS WITH A WARM FRONT OVER CENTRAL ONTARIO EXTENDING FROM THE PARENT LOW NORTH OF LAKE WINNIPEG. DEBRIS CLOUDS FROM CONVECTION EARLIER ON TODAY ACROSS MINNESOTA AND NORTHERN WISCONSIN HAVE STARTED PUSHING INTO THE AREA WITH THE MQT RADAR JUST SHOWING A FEW SPOTTY RETURNS OVER CENTRAL LAKE SUPERIOR (EVEN A LIGHTNING STRIKE) AND ALONG THE SOUTH SHORE OF LAKE SUPERIOR RIGHT ALONG OF THE LEADING EDGE OF THE DEEPER MOISTURE AXIS. MAIN FORECAST CONCERNS FOR THE REST OF THE EVENING REVOLVE AROUND THESE SPOTTY SHOWERS...THEN LOW TEMPERATURES AND CLOUD COVER. A FEW CHANGES HAVE BEEN MADE TO THE ONGOING FORECAST. HAVE INCREASED CLOUD COVER ACROSS THE NORTHERN CWA TO ACCOUNT FOR THE CONVECTIVE DEBRIS PASSING OVERHEAD. HAVE ALSO ADDED A CHANCE OF A SPRINKLE ACROSS WHITEFISH BAY AND THE SOO DUE TO THESE SPOTTY SHOWERS...JUST FOR THE EVENING HOURS. ONE SHOWER TO THE EAST OF MQT LOOKS TO HAVE SOME BEEFIER RETURNS AT 3.5KFT THAT HAS POTENTIAL TO REACH THE GROUND DESPITE THE DRY AIR PRESENT (RUC ANALYZED 900-700MB RH 25-30 PCT). PRESSURE GRADIENT BEGINS TO TIGHTEN LATE OVERNIGHT AS THE SURFACE HIGH CONTINUES ITS SE SLIDE. SOUTHERLY RETURN FLOW ON THE WEST SIDE OF THIS HIGH WILL THEN KICK IN AND KEEP OUR TEMPERATURES FROM FALLING AS MUCH AS THE PREVIOUS NIGHTS LOWS. STILL BELIEVE THAT TEMPERATURES WITHIN THE COLD SPOTS AND AREAS ACROSS NE LOWER (WHERE THE PRESSURE GRADIENT TIGHTENS LAST) WILL DROP INTO THE LOWER 40S BUT FOR THE REMAINING AREAS...LOWS WILL FALL INTO THE MIDDLE TO UPPER 40S. ZONES OUT SHORTLY. MPC && .DISCUSSION...ISSUED AT 335 PM EDT SAT APR 21 A HUDSON BAY HIGH IS BEGINNING TO MOVE TO THE EAST SO THAT THE RETURN FLOW IS SLOWLY STARTING. THE OMEGA BLOCK AT 500 MB IS BREAKING DOWN SO THAT THE RIDGE AXIS IS OVER THE WESTERN GREAT LAKES. TO THE WEST OF THAT, THE NEXT SYSTEM WHICH IS EXPECTED TO BREAK DOWN THE RIDGE AND BRING A COLD FRONT THROUGH THE FORECAST AREA ON SUNDAY NIGHT. SO THE MAIN CONCERN IN THE SHORT TERM WILL BE TEMPERATURES AND HUMIDITY AND WIND FOR SUNDAY. TONIGHT...THE GRADIENT BEGINS TO PICK UP, BUT WITH THE SFC INVERSION THAT IS EXPECTED TO SET UP THIS EVENING, THE WINDS WILL REMAIN BELOW 10 MPH. WITH THE STRONG INVERSION AND LOWER SFC WINDS, THE HUMIDITY RECOVERY IS EXPECTED TO BE POOR WITH THE DEWPOINTS EXPECTED TO REMAIN IN THE LOWER TO MID 30S OVERNIGHT. THERE WILL ONLY BE A FEW HIGH CLOUDS SO THE RADIATIONAL COOLING WILL COOL THINGS A BIT, BUT IT WILL REMAIN WARMER THAN LAST NIGHT AS THE SOUTH WIND STAYS UP ALL NIGHT. SUNDAY...AS THE SUN PEEKS OVER THE HORIZON, THE TEMPERATURES WILL BEGIN TO ZOOM INTO THE MID TO UPPER 70S WITH SEVERAL LOWER 80S THROWN IN. THE MET AND MAV NUMBERS RANGE FROM THE UPPER 70S IN PLN AND GLR TO THE LOWER 80S IN GOV, WITH UPPER 70S NEAR THE LAKE SHORES. 950 MB WINDS ON BOTH MODELS ARE RUNNING 25 TO 30 KNOTS THROUGH THE AFTERNOON AND THE SFC WINDS ARE EXPECTED TO BE SUSTAINED AROUND 15 KNOTS AT THE AVIATION SITES. FACTORING IN THE 20FT WIND LEVEL AND THE 10 MIN AVG OF THE RAWS SITES WOULD EXPECT THAT EVEN IF 15 MPH ISN`T SUSTAINED, THERE WILL BE FREQUENT GUSTS TO 20 MPH. THIS IS DUE TO THE FACT THAT WE`RE NOT GOING TO JUST MIX THROUGH 950 OR 850 MB, BUT PROBABLY THROUGH 750 MB LIKE YESTERDAY. THIS WILL HELP KEEP THE SFC RH DOWN AS THE 850 MB RH IS EXPECT TO BE <10% ON THE NAM AND <25% ON THE GFS. WITH THE SW FLOW THE 850 MB TEMPERATURES ARE EXPECTED TO BE AROUND +14C WHICH WHEN MIXED OUT WOULD BRING IN TEMPERATURES AROUND THE LOWER TO MID 80S. SO, HOWEVER YOU CUT IT, IT LOOKS LIKE WE WILL MEET RED FLAG CRITERIA FOR THE AFTERNOON. LUTZ && SUNDAY NIGHT...SFC HIGH PRES PATTERN BEGINS TO BREAK DOWN OVER THE GREAT LAKES IN THE EVENING...AS A STORM SYSTEM OVER THE ROOKIES MOVES INTO THE CENTRAL PLAINS. EXTENDED MODELS BRING THE SYS INTO THE WRN LAKES BTW 06Z AND 12Z MONDAY. AT UPPER LVLS...THE UPPER RIDGING PATTERN ALSO BEGINS TO BREAK DOWN ACRS THE GREAT LAKES REGION...AS AN UPPER LOW ROTATES OUT OF THE CENTRAL PLAINS AND TOWARD THE UPPER LAKES. THE UPPER TROF IS FORECAST TO MOVE INTO THE WRN LAKES AROUND 12Z MONDAY. 850/500 MB RH INCREASES TO 80 PCT OVR THE LAKES BY 12Z MONDAY IN ADVANCE OF THE SFC AND UPPER LVL FEATURES. THEREFORE WILL KEEP THE MENTION OF SHOWERS IN THE FORECAST OVERNIGHT SUNDAY...WITH THE BEST CHANCES BEING OVER WRN LWR AND EAST UPPER WHERE MSTR INCREASES FIRST. WILL KEEP OVERNIGHT LOWS GENERALLY IN THE 50S...DUE TO INCREASING CLOUDS AND MODERATE SOUTHWEST FLOW. MONDAY...SURFACE FRONT MOVES OVER THE LAKES DURING THE DAY...EXITING INTO LAKE HURON AROUND 00Z TUESDAY. UPPER TROUGH QUICKLY MOVES OVER THE STATE IN THE AFTERNOON...WITH NEARLY ZONAL FLOW DEVELOPING LATE AFTN. 850/500 MB RH QUICKLY BEGINS TO DRY OUT OVER THE WRN LAKES AFT 18Z MONDAY...DROPPING FROM AROUND 80 PCT IN THE MORNING TO ARND 40 PCT BY 21Z. WILL MENTION LIKELY POPS ACRS THE FCST AREA THRU THE MORNING. IN THE AFTN...WILL DROP POPS TO CHC OVER THE WRN CWA WHILE MAINTAINING LIKELY POPS OVER THE ERN CWA INTO THE EVENING. WILL MENTION DRY CONDS MONDAY NIGHT ACRS THE ENTIRE FCST AREA...AS SFC HIGH PRESSURE BUILDS BACK ACRS THE REGION AND UPPER ZONAL FLOW PERSISTS. 850/500 MB RH SHOWING DRYING TO AROUND 30 PCT MONDAY NIGHT INTO TUESDAY. WILL MENTION AFTN HIGHS IN THE 55 TO 60 DEGREE RANGE WITH CLOUDS AND RAIN. OVERNIGHT LOWS...WITH CLEARING SKIES AND CALMING WINDS...SHOULD DROP BACK INTO THE LOWER AND MID 30S. TUESDAY...HIGH PRESSURE AND 500MB ZONAL FLOW WILL REMAIN OVER THE REGION THROUGH THE DAY. COLDER 850MB AIR WILL FILTER BACK OVER THE STATE DURING THE DAY...AS 850 MB TEMPS DROP FROM ARND 10C MONDAY TO AROUND +1C TUESDAY AFTN. WILL MENTION AFTN HIGHS IN THE 50S ACRS THE FCST AREA. OVERALL WILL MENTION DRY CONDS DUE TO SFC RIDGING AND 850/500 RH AROUND 40 PCT. HOWEVER EXPECT AFTN CU DEVELOPMENT DUE TO 850 AND 500 MB COLD POOLS ALOFT AFFECTING THE UPPER LAKES. SUBSIDENCE CONDS PERSIST TUESDAY NIGHT...THEREFORE WILL MENTION DRY CONDS INTO WEDNESDAY. WEDNESDAY THROUGH SATURDAY...SFC RIDGING AND NEARLY ZONAL FLOW ALOFT WILL REMAIN OVER THE UPPER LAKES AND UPPER MIDWEST WEDNESDAY INTO THURSDAY. WILL MENTION DRY CONDS AGAIN WEDNESDAY AND EARLY THURSDAY. WILL KEEP HIGHS IN THE 50S WEDNESDAY AS SFC AND UPPER LEVEL FEATURES WILL BE SIMILAR TO THOSE ON TUESDAY. THURSDAY THROUGH SATURDAY... MODEL BEGIN TO DIFFER WITH RESPECT TO SURFACE AND UPPER LEVEL FEATURES AFFECTING THE REGION. A STORM SYSTEM WILL BE DEVELOPING OVER THE SRN ROOKIES WED...AND WILL BEGIN PUSHING NORTH EARLY THURSDAY MOVING TOWARD IND/ILL BY 12Z THURSDAY...BEFORE MOVING OVER THE OHIO VALLEY BY THURSDAY EVENING. HOWEVER MODELS DO HANDLE THE EASTWARD MOVEMENT OF THIS SYSTEM DIFFERENTLY THURSDAY AFTERNOON INTO FRIDAY...WITH THE ECMWF PUSHES THE SFC FEATURE FASTER TOWARD THE EAST COAST. AT UPPER LVLS...MODELS ARE DISORGANIZED WITH THE 500 MB TROUGH/RIDGE PATTERN MOVING OVER THE UPPER MIDWEST THURSDAY...MOVING INTO THE ERN LAKES FRIDAY MORNING. OVERALL SEEMS LIKE A PRETTY STRONG UPPER RIDGE IS BEING BROKEN DOWN TO FAST THURSDAY...WHILE MODELS KEEP THE SFC LOW TO THE SOUTH OF THE STATE. OVERALL THOUGHT IS FORECAST WILL REMAIN DRY THURSDAY BUT WILL KEEP A MENTION OF LIGHT SHOWERS OVER THE SRN PORTIONS OF THE FORECAST AREA THURSDAY AFTN. OVERALL SURFACE AND UPPER LVL RIDGING APPEARS TO MOVE SLOWLY BACK INTO THE STATE FRIDAY...SO WILL MENTION DRY CONDS INTO FRIDAY NIGHT. HIGH TEMPS SHOULD REMAIN IN THE 50S THURSDAY AND FRIDAY. SATURDAY...WILL MENTION A CHANCE OF SHOWERS OVER THE FORECAST AREA...AS A SURFACE TROUGH LINGERS OVER THE EASTERN LAKES...WHILE AN UPPER TOUGH MOVES OVER THE UPPER MIDWEST AND PLAINS FRIDAY NIGHT...AND INTO THE WRN LAKES REGION BY SATURDAY AFTERNOON. SWR && .APX WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING...ALL OF NORTHERN LOWER...SUNDAY AFTERNOON AND EARLY EVENING. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 129 AM CDT SUN APR 22 2007 .UPDATE... UPDATE FORECAST TO REMOVE SEVERE THUNDERSTORM WATCH AND REFRESH GRIDS. LITTLE CHANGE TO PREVIOUS FORECAST SHORT TERM...AS BEST SEVERE POTENTIAL APPEARS TO BE OVER. LOCALLY HEAVY RAIN ON FAR WESTERN PERIPHERY OF CWA THROUGH THE NEXT FEW HOURS. OTHERWISE TREND OF LATEST RUC 13 AND 4 KM WRF REFLECTIVITY TRENDS SHOW WEAKENING TREND AS UPPER JET TRANSLATES A BIT FARTHER NORTH AND EAST. && .PREV DISCUSSION... /ISSUED 300 PM CDT SAT APR 21 2007/ DISCUSSION... REMNANTS OF MORNING CONVECTION HAVE PRETTY MUCH LIFTED OUT OF AREA WITH ONE AREA OF REMAINING THUNDERSTORMS ACROSS E TWIN CITIES METRO INTO W WI. THESE SHOULD PRETTY MUCH BE OUT OF AREA BY 6 PM. GOOD MIXING IN S MN HAS ALLOWED FOR SOME GUSTS TO AROUND 40 MPH. WILL LEAVE WIND ADVISORY ACROSS SC MN UNTIL 8 PM THIS EVENING. MAIN FOCUS FOR THUNDERSTORMS TONIGHT WILL BE IN WC MN WHERE AXIS OF ELEVATED INSTABILITY IN PLACE. BY 06Z RATHER STRONG UPPER DIVERGENCE IN RIGHT ENTRANCE REGION OF UPPER JET COMES INTO PLAY PROVIDING A GOOD LIFTING MECHANIZM. CONTINUED TO CARRY A POPS ACROSS CENTRAL MN LATE TONIGHT DUE TO CONTINUED STRONG SOUTHERLY FLOW AND ANOTHER PUSH OF WARM ADVECTION. STREAM OF MOISTURE WILL CONTINUE TO LIFT INTO AREA INTO TOMORROW AHEAD OF STRONG UPPER TROF WITH PWATS OVER 1.25 INCH. FEEL THAT MAIN WEATHER THREAT WITH THIS SYSTEM SUNDAY WILL PROBABLY BE HEAVY RAINS WITH SOME HAIL WITH HIGH PWATS AND CONTINUED STRONG FORCING KEEPING AREA MAINLY CLOUDY. VERY MILD TEMPERATURES TONIGHT WILL CONTINUED MODERATE SOUTH FLOW AND INCREASING DEWPOINTS AHEAD OF COLD FRONT. LEFT THE CHANCE OF SHOWERS IN FOR SOUTHERN AREAS TUESDAY INTO WEDNESDAY AS NEXT SYSTEM MOVES THROUGH THE CENTRAL PLAINS...BUT CONFLUENT FLOW ACROSS CENTRAL MN SHOULD LIMIT THE NORTHWARD PROGRESS OF PRECIPITATION. MPX WATCHES/WARNINGS/ADVISORIES... MN...WIND ADVISORY UNTIL 8 PM CDT THIS EVENING OR BLUE EARTH-BROWN-FARIBAULT-FREEBORN-MARTIN-REDWOOD- STEELE-WASECA-WATONWAN-YELLOW MEDICINE COUNTY(IES). WI...NONE. $$ && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ DWE/JPR mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 430 AM CDT SUN APR 22 2007 .SHORT TERM...TODAY THROUGH MONDAY...ANOTHER WARM AND MOSTLY SUNNY DAY IS ON TAP TODAY AS HIGH PRESSURE AT THE SURFACE AND ALOFT CONTINUES TO DOMINATE OVER THE ARKLAMISS. LATEST SFC ANALYSIS HAS HIGH PRESSURE CENTERED OVER THE CAROLINAS. THE HIGH WILL DRIFT SOUTHEAST TODAY AND OFF THE GA/SC COAST MONDAY WHILE RIDGING WEST ACROSS THE GULF COAST STATES. THIS WILL MAINTAIN OUR SE TO S LOW LEVEL FLOW AND SERVE TO GRADUALLY INCREASE LOW LEVEL MOISTURE OVER OUR REGION. SATELLITE IMAGERY/RUC ANALYSIS EARLY THIS MORNING HAS THE LARGE UPPER RIDGE OVER THE EASTERN CONUS WITH THE RIDGE AXIS JUST EAST OF OUR CWA. ALSO NOTED WAS A NEARLY STACKED LOW MOVING OVER SW KANSAS. THIS LOW WILL BE DEFLECTED TO THE NE AS THE UPPER RIDGE SLOWLY SHIFTS EAST TODAY. SOME MID AND HIGH LEVEL CLOUDS WERE SEEN STREAMING EAST TOWARD OUR DELTA REGION FROM THE CONVECTION ASSOCIATED WITH THE LOW. THESE CLOUDS SHOULD THIN AS THEY MOVE INTO OUR AREA AND WILL DO LITTLE TO HOLD TEMPERATURES FROM PEAKING OUT NEAR 80 DEGREES AGAIN THIS AFTERNOON. AS THE LOW PRESSURE SYSTEM MOVES OFF TOWARD THE GREAT LAKES REGION TONIGHT THE TRAILING COLD FRONT WILL STALL WELL NORTHWEST OF OUR AREA NEAR THE OZARKS. ALTHOUGH NO PRECIPITATION ASSOCIATED WITH THE FRONT IS EXPECTED IN OUR AREA...MODELS CONTINUE THE SURGE OF MOISTURE NORTHWARD AHEAD OF THE FRONT. THIS WILL RESULT IN SOME STRATUS DEVELOPING OVER THE WESTERN HALF OF OUR CWA TOWARD MONDAY MORNING A POSSIBLY A FEW AFTERNOON SHOWERS IN THE WEST. PREVIOUS FORECASTS HAVE TRIMMED THIS SLIGHT CHANCE POPS BUT THE UKMET/GFS/NAM/NGM ALL GENERATE SOME LIGHT QPF IN OUR WESTERN ZONES MONDAY AND WL NOT IGNORE. BY MONDAY AFTERNOON SURFACE DEW POINTS ARE EXPECTED TO BE BACK INTO THE LOW TO MID 60S WITH PWS AROUND 1.3 INCHES. ALTHOUGH RIDGING ALOFT WL ACTUALLY BE STRENGTHENING SOME FROM THE WESTERN GULF AHEAD OF THE THE NEXT UPPER LOW THAT WILL BE NEARING THE FOUR CORNERS REGION...MODEL SOUNDINGS INDICATE THAT DAYTIME HEATING WL WEAKEN THE EXISTING CAP AND RESULT IN ENOUGH INSTABILITY TO PRODUCE A FEW SHOWERS BY LATE AFTERNOON. THIS SLIGHT CHANCE OF SHOWERS WILL OCCUR ALONG AND WEST OF THE MS RIVER. WITH THE ANTICIPATED CLOUD COVER MONDAY HAVE CUT A FEW DEGREES OFF MAX TEMPS IN THE WEST AND CENTRAL. LATEST MAV GUIDANCE MAX TEMPS WERE AMONG THE HIGHEST ENSEMBLE MEMBERS AS WELL. IT WILL STILL BE WARM WITH MOST SITES TOPPING OUT AROUND 80 DEGREES AGAIN. /22/ .LONG TERM...(MONDAY NIGHT THROUGH NEXT SUNDAY)... FORECAST IS A LITTLE TRICKIER FOR THE PERIOD FROM MONDAY NIGHT UP UNTIL WEDNESDAY WITH THIS FORECAST PACKAGE. PAST FEW FORECASTS WERE CONFIDENT WITH ENTIRELY DRY WEATHER OVER THIS PERIOD WHILE WE WAIT FOR AN ORGANIZED SYSTEM TO BRING THE REGION SHOWER AND THUNDERSTORM CHANCES BY WEDNESDAY. NOW MODELS SUGGEST THAT MOISTURE RETURN AND LOW LEVEL CONVERGENCE ALONG THE NORTHWEST EDGE OF THE ARKLAMISS COULD SPARK SOME SHOWERS (AND MAYBE A STORM OR TWO) TUESDAY AND TUESDAY NIGHT. MAV/MEX POPS STILL CUT SOME FOR THESE PERIODS OWING TO PROBABLE THERMAL CAPPING ISSUES...BUT A LITTLE PRECIP CANNOT BE RULED OUT BEFORE WEDNESDAY MORNING IN NORTHWEST MS...SOUTHEAST AR AND NORTHEAST LA. OTHERWISE...EXPECT MONDAY NIGHT THROUGH TUESDAY NIGHT TO BE FRAUGHT WITH BOUTS OF NIGHT TIME LOWER CLOUDS AND DAYTIME CUMULUS...BUT PARTLY CLOUDY OVERALL. TEMPERATURES WILL TREND MUCH WARMER WITH LOWS PRIMARILY RANGING FROM 60 TO 65 WITH HIGHS 80 TO 85. GFS GUIDANCE TEMPS LOOK DECENT IN THAT REGARD. BY WEDNESDAY A RATHER POTENT UPPER LEVEL DISTURBANCE WILL HEAD TOWARD THE MID AND LOWER MS VALLEYS WITH AN ASSOCIATED SURFACE FRONT MOVING INTO THE ARKLATEX. DEEP SOUTHERLY FLOW WILL TRANSPORT MOISTURE NORTH INTO THE REGION FROM THE GULF OF MEXICO...ALTHOUGH THE "QUALITY" OF MOISTURE RETURN IS NOT TOO IMPRESSIVE. SHOULD STILL BE ENOUGH JUICE AROUND TO TRIGGER SCATTERED SHOWERS AND THUNDERSTORMS (MOST CONCENTRATED WEST) BY AFTERNOON AS ATMOSPHERIC FORCING INCREASES. PROGGED VALUES OF WIND SHEAR MEET THRESHOLDS FOR ORGANIZING STORMS INTO SEVERE MODES...BUT THE POSITIONING OF THE SURFACE LOW WILL NOT BE OPTIMUM FOR THE GENERATION OF SEVERE WEATHER. TAME LAPSE RATES WILL EQUATE TO MODEST INSTABILITY AT BEST (1000 TO 1500 JOULES) AND SHEAR COULD BE A LITTLE MUCH FOR STRUGGLING UPDRAFTS TO "KEEP UP WITH". THESE "CONS" FOR WIDESPREAD SEVERE WEATHER ARE ENOUGH FOR ME TO KEEP THE HWO CLEAR FOR NOW...BUT THERE STILL ARE SOME POSSIBILITIES OF INTENSE CONVECTION BEING AROUND WEDNESDAY AFTERNOON INTO THE WEDNESDAY EVENING IN THE AREA...SO STAY TUNED TO LATER FORECASTS. AS FOR POPS...GUIDANCE CAME IN WITH MAINLY 30 TO 50 PERCENT FOR WEDNESDAY AND WEDNESDAY NIGHT AND I FOUND ENOUGH EVIDENCE TO INCREASE 10 TO 15 POINTS IN NORTHWEST ZONES WEDNESDAY AND 10 POINTS NEARLY AREAWIDE WEDNESDAY NIGHT. EXPECT HIGHS WEDNESDAY IN THE UPPER 70S TO LOWER 80S (WHICH IS SEVERAL DEGREES WARMER THAN GUIDANCE) WITH LOWS MAINLY IN THE LOWER 60S...WHICH IS AGAIN WARMER THAN GUIDANCE. ANNOYING MODEL DISCREPANCIES CONTINUE AFTER WEDNESDAY NIGHT. LATEST GFS RUN HAS TRENDED COMPLETELY TO THE PREVIOUS EURO IDEA OF A STRONG FRONTAL PUSH THROUGH THE REGION THURSDAY WHILE THE EURO MODEL HAS BACKED OFF FROM THIS IDEA SOME. THE TREND OF THE EUROPEAN MODEL HAS BEEN MORE CONSISTENT THAN THE ERRATIC GFS...SO I HEDGED OUR FORECAST TOWARD THE FORMER MODEL. THAT HEDGING BASICALLY ENTAILS GOING WARMER THAN MEX GUIDANCE THURSDAY THROUGH FRIDAY NIGHT SINCE THE FRONT WILL LIKELY HANG UP NEAR THE SOUTHERN EDGES OF THE CWA. EXPECT LOWS TO DIP DOWN INTO THE 50S AGAIN FOR MOST LOCALES THURSDAY NIGHT...BUT THEN TREND SLOWLY BACK UPWARDS THROUGH SATURDAY AS THE FRONT MEANDERS BACK NORTH. HIGHS SHOULD DIP DOWN INTO THE 70S NORTHERN AREA THURSDAY AND FRIDAY FOLLOWED BY A RETURN TO WIDESPREAD 80S THEREAFTER. MODELS ARE REALLY ALL OVER THE PLACE WITH REGARDS TO ANOTHER...WEAKER...DISTURBANCE THAT MAY SLOWLY HEAD IN OUR DIRECTION NEXT WEEKEND. CONFIDENCE IS LOW AT THIS POINT THAT THIS FEATURE WILL BRING MUCH IN THE WAY OF PRECIP AND EVEN GFS GUIDANCE HAS COME DOWN SOME WITH THIS RUN IN TERMS OF POPS. WILL KEEP MENTION OF PRECIP OUT OF NEXT WEEKEND`S FORECAST FOR NOW. /BB/ && .AVIATION...MVFR CONDITIONS DUE TO VISIBILITY RESTRICTIONS 3-5SM WILL OCCUR OVER THE SOUTHERN HALF OF THE AREA THROUGH 14Z THIS MORNING. WINDS WILL PROVIDE ENOUGH MIXING TO HAMPER FOG DEVELOPMENT IN THE NORTH THIS MORNING. ALTHOUGH WIND GUSTS TO 15-20KTS ARE EXPECTED IN THE DELTA TODAY...VFR CONDITIONS EXPECTED TO PREVAIL AFTER 15Z ACROSS ALL TAF SITES TODAY. IFR TO LIFR CEILINGS ARE EXPECTED TO DEVELOP FROM THE SW TONIGHT REACHING MOST OF THE WESTERN HALF OF THE AREA BY 12Z. CEILINGS ARE EXPECTED TO BE AT OR BELOW 500FT AT ALL TAF SITES EXCEPT MEI AND GTR WHERE CEILINGS AROUND 1KFT CAN BE EXPECTED. /22/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 81 60 79 63 / 0 5 7 6 MERIDIAN 80 57 80 60 / 0 5 6 6 VICKSBURG 81 62 79 63 / 0 7 15 8 HATTIESBURG 80 59 81 63 / 0 4 8 4 NATCHEZ 80 62 79 65 / 0 5 15 7 GREENVILLE 81 62 79 65 / 0 12 15 12 GREENWOOD 80 61 79 64 / 0 8 15 12 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ SHORT TERM:22 LONG TERM: 50 ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 325 AM EDT SUN APR 22 2007 .SHORT TERM /TODAY THROUGH TUESDAY NIGHT/... TODAY/TONIGHT: CONTINUED QUIET... GENERALLY CLOUD-FREE... DRY AND WARM WITH SURFACE HIGH PRESSURE AND HIGHLY AMPLIFIED MID LEVEL RIDGING OVERHEAD. APART FROM THE VERY WARM TEMPERATURES PEAKING IN THE 80-84 RANGE TODAY... OF NOTE WILL BE THE LOW RELATIVE HUMIDITY VALUES WITH EXPECTATIONS OF DEWPOINTS DROPPING WELL DOWN THROUGH THE 30S THIS AFTERNOON... AND POSSIBLE LOWER. SEE FIRE WEATHER DISCUSSION BELOW FOR MORE DETAILS. LOWS TONIGHT GENERALLY 46-51... BUT OUTLYING RURAL AREAS MAY SEE COOLER READINGS. MONDAY THROUGH TUESDAY NIGHT: THE SURFACE HIGH SHIFTS SLOWLY SOUTHEAST AND OFFSHORE STARTING THIS AFTERNOON... INTRODUCING STEADIER SOUTHWEST WINDS AND SLOWLY INCREASING THICKNESSES AND MOISTURE OVER CENTRAL NC. THIS MORNING`S MID LEVEL TROUGH AND SURFACE LOW OVER THE PLAINS WILL DAMPEN AS IT HEADS NORTHEAST THROUGH THE GREAT LAKES AND NEW ENGLAND THROUGH EARLY TUESDAY. THIS TROUGH HELPS TAMP DOWN THE MID LEVEL RIDGE OVER THE GULF OF MEXICO AND SOUTHEAST STATES... A BIT MORE PROFOUND ON THE NAM THAN THE GFS. AN 850 MB THETA-E RIDGE TO OUR WSW NOSES TOWARD WESTERN NC... AND MODELS SHOW A 40-50 KT LOW LEVEL JET ZIPPING ACROSS VA MONDAY NIGHT... HOWEVER THE WESTERLY-SHIFTING 850 MB WINDS SHOULD LIMIT MOISTURE EAST OF THE MOUNTAINS AND MOST OF THE LIFT IS TO OUR NORTH... SO WILL STAY DRY THROUGH MONDAY NIGHT BUT EXPECT INCREASING CLOUDS NW TO SE. HIGHS 80-84 MONDAY... FOLLOWED BY LOWS 53-56. THEN ON TUESDAY... THE FRONT BECOMES W-E ORIENTED TO OUR NORTH WITH MODELS DEVELOPING A SURFACE LOW OVER SOUTH CENTRAL VA LATE IN THE DAY. PRECIPITABLE WATER VALUES REMAIN HIGH ENOUGH... ABOUT 150% OF NORMAL... AND INCREASING INSTABILITY WITH CAPES RISING OVER 500 J/KG FAVORS AT LEAST A LOW CHANCE OF CONVECTION TUESDAY AFTERNOON/EVENING DESPITE A WARM POCKET IN THE MID LEVELS. HIGHS 80-83... WITH LOWS TUESDAY NIGHT 55-60 UNDER PARTLY TO MOSTLY CLOUDY SKIES. -GIH && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... LITTLE CHANGE NEEDED. HAVE KEPT A SLIGHT CHANCE OF AN AFTERNOON OR EVENING STORM ACROSS THE NORTH WEDNESDAY GIVEN THE SURFACE LOW THAT THE GFS/ECMWF ZIP ACROSS NORTHERN VA LATE IN THE DAY AND THE TAIL END OF ITS WEAK SURFACE TROUGH THAT DRAGS ALONG THE NC/VA BORDER. HOWEVER WITH THE MID LEVEL SHORTWAVE RIDGING AHEAD OF THE SOUTHERN PLAINS TROUGH... ANY ACTIVITY SHOULD BE QUITE ISOLATED. THIS WAVE DAMPENS AS IT HEADS UP THROUGH THE OHIO VALLEY AND INTO THE NORTHEAST THROUGH FRIDAY. THE TRAILING COLD FRONT MOVES INTO THE NC MOUNTAINS LATE THURSDAY AND REALLY LOSES DEFINITION THROUGH FRIDAY... SO MUCH THAT LOW LEVEL THICKNESS... WHICH REMAIN ABOVE NORMAL THROUGH THIS PERIOD... SHOW NO RESPONSE THROUGH FRIDAY. LARGE SCALE FORCING FOR LIFT WANES CONSIDERABLY... SO QPF MAY BE SORELY LIMITED IN OUR NECK OF THE WOODS... BUT HAVE KEPT CHANCE POPS THURSDAY AFTERNOON THROUGH FRIDAY MORNING. DRY THEREAFTER WITH THE CONSISTENT GFS SHOWING A DRY COLUMN AND STABILIZING MID LEVELS THROUGH SATURDAY. HIGHS IN THE MID 80S WEDNESDAY AND IN THE UPPER 70S TO AROUND 80 THURSDAY-SATURDAY WITH AN INCREASE IN CLOUD COVER. LOWS MOSTLY IN THE MID 50S TO LOWER 60S EACH MORNING. -GIH && .AVIATION /06Z-06Z/... DURING THE OVERNIGHT HOURS OF FRIDAY...RAPID EVENING COOLING OVER CENTRAL NORTH CAROLINA...COMBINED WITH SLIGHTLY HIGHER DEW POINTS AT THE TIME...RESULTED IN A BRIEF PERIOD OF MVFR-TO-IFR FOG AT KFAY AND KRWI. EARLY THIS MORNING...THE TEMPERATURE/DEW POINT SPREAD IS HIGHER...AND IN A FEW LOCATIONS THERE HAS BEEN JUST ENOUGH MIXING TO RESULT IN A LIGHT...BUT OBSERVED...WIND FROM THE SOUTHWEST. AROUND 06Z...SURFACE TEMPERATURES ACTUALLY ROSE AT KRWI. DEW POINTS ARE HIGHEST TOWARD THE EAST AND HAVE PROVIDED FOR A BRIEF PERIOD OF MVFR...LIGHT FOG AT KRWI...BUT ELSEWHERE ANTICIPATE VFR CONDITIONS. GFS MODEL SOUNDINGS SUGGEST SLIGHTLY COOLER TEMPERATURES BETWEEN 800MB AND 500MB CENTRAL AND EAST THIS AFTERNOON...WHICH WITH DIURNAL MIXING COULD RESULT IN A FEW CU IF THE SOUNDINGS NEAR KRDU AND KRWI VERIFY VERY CLOSE TO THE FORECAST. THE GFS SOUNDING APPEARS TO BE A LITTLE HIGH ON ITS SURFACE DEW POINT AND IF DEW POINTS ARE MUCH LOWER THERE WOULD BE COMPLETE BLUE AGAIN TODAY. FEW CU AT MOST WITH SURFACE WINDS 10KT OR LESS...VEERING TO THE WEST EARLY AND RETURNING TO SOUTH-TO-SOUTHWEST LATE. && .FIRE WEATHER... VISIBLE SATELLITE IMAGERY FROM YESTERDAY REVEALED FIRES BURNING IN HARNETT... CUMBERLAND... AND HOKE COUNTIES... AS RELATIVE HUMIDITY VALUES PLUMMETED TO 16-20% DURING THE AFTERNOON... MUCH LOWER THAN MOS GUIDANCE VALUES INDICATED. WHILE A LIGHT SOUTHWEST BREEZE MAY KEEP DEWPOINTS FROM CRASHING QUITE AS MUCH AS THEY DID YESTERDAY WHEN THE WINDS WERE LIGHTER AND VARIABLE... WITH NO CHANGE IN AIR MASS... ANOTHER STEEP DROP IN RELATIVE HUMIDITY VALUES IS EXPECTED TODAY. FORECAST DEWPOINTS WILL BE ABOUT 10 DEGREES BELOW MOS GUIDANCE VALUES... CLOSE TO THE NUMBERS ONE GETS WHEN THE LOWEST 100 MB ON THE MORNING RUC SOUNDING IS MIXED. THE LOWEST HUMIDITY SHOULD BE IN THE NORTHEAST CWA. THERE SHOULD BE A RAPID RECOVERY INTO THE 30-40% RANGE TOWARD SUNSET. WHILE WIND WILL NOT BE A MAJOR FIRE CONCERN WITH W TO SW SURFACE WINDS GENERALLY 5 TO 10 MPH AND FAIRLY LIGHT ALOFT... GIVEN THE FINE FUEL MOISTURE LEVELS THAT ARE DOWN TO ABOUT 3-5%... THESE DRY RH VALUES WILL NOT HELP THIS SITUATION. EXPECT MIXING HEIGHTS TODAY UP TO 8000 FT. -GIH/DJF && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...HARTFIELD LONG TERM...HARTFIELD AVIATION...DJF FIRE WEATHER... nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 230 AM CDT SUN APR 22 2007 FORECAST CHALLENGE CONCERNS ADDITIONAL RAINFALL/FLOOD HEADLINES AND TEMPERATURES. MODELS IN REASONABLE AGREEMENT THROUGH PERIOD SO WILL USE BLEND FOR FORECAST. CURRENT WEAKENING CONVECTIVE COMPLEX CONTINUES TO AFFECT SE HALF OF FA SOUTHWARD INTO EASTERN SD. RUC AND GFS WEAKEN AND SHIFT LOW LEVEL JET FLOW MORE WESTERLY AND WARM ADVECTION ALSO SHIFTS EAST SO DO NOT EXPECT ANY WEST/NORTHWARD EXPANSION OF CURRENT PCPN BAND. WILL MONITOR FOR T TRENDS AND LIKELY MAINTAIN HIGH POPS OVER FAR EAST DURING AM. WITH THREE HOUR FLASH FLOOD GUIDANCE UNDER CONVECTION AT > 2.5 INCHES...CONVECTION WEAKENING UPSTREAM AND ABOVE TRENDS FEEL POTENTIAL FOR ADDITIONAL HEAVY RAIN PRODUCING FLASH FLOODING WILL DIMINISH ENOUGH TO CANCEL ONGOING WATCH. FOR REMAINDER OF FA COLUMN DRIES TODAY REFLECTED BY CLEARING OVER CENTRAL WESTERN ND. THERE IS AN AREA OF VFR CIGS OVER SASK HOWEVER TIMING WOULD NOT BRING IT IN UNTIL LATE AFTERNOON. MODEST COLD ADVECTION WILL OFFSET SOLAR SOMEWHAT BUT WILL TREND TEMPERATURES TOWARDS WARMER NAM/NGM NUMERICAL GUIDANCE AS GFS SHOWING MORE CLOUD COVER THAN EXPECTED. FARTHER EAST MORE CLOUD COVER EXPECTED SO COOLER GUIDANCE ACCEPTED. SHORT WAVE RIDGE SHIFTS EAST MONDAY AS REGION COMES UNDER INCREASINGLY SPLIT MID LEVEL FLOW. COLD ADVECTION SHUTS DOWN MONDAY HOWEVER WITH COOLER COLUMN AND INTEGRATED RH FIELDS INDICATING SOME POTENTIAL FOR CLOUDS WILL STICK PRETTY CLOSE TO NUMERICAL GUIDANCE. SURFACE LOW PRESSURE ORGANIZED OVER CENTRAL PLAINS AS SOUTHERN STREAM UPPER LOW CLOSES OFF. WILL MAINTAIN LOW POPS OVER FAR SOUTH CLOSER TO DEEPER MOISTURE SOURCE AND WEAK NORTHERN STREAM MID LEVEL TROUGH PASSAGE. NEXT WAVE OF INTEREST LATE IN WORK WEEK AND WILL MAINTAIN POP MENTION FOR THUR NIGHT/FRIDAY. UNTIL THEN WARMING COLUMN SHOULD BRING TEMPERATURES AT OR ABOVE AVERAGE. && AVIATION...MVFR/ISOLD IFR CIGS WITHIN CONVECTION THIS MORNING FROM FAR SE ND INTO WESTERN MN SHOULD GRADUALLY IMPROVE AS PCPN BAND SHIFTS EAST. REMAINDER OF FA SHOULD BE VFR TODAY WITH SOME ISOLD MORNING BR ON BACK EDGE OF CURRENT PCPN SHIELD. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ VOELKER nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE EUREKA CA 330 AM PDT SUN APR 22 2007 .SYNOPSIS...AN UPPER LEVEL TROUGH WILL MOVE EAST ACROSS NORTHWEST CALIFORNIA TODAY THUS SHOWER ACTIVITY IS EXPECTED TO DECREASE THIS AFTERNOON. AN UPPER LEVEL RIDGE WILL BUILD OVER THE REGION TONIGHT WITH WARMER AND DRIER CONDITIONS EXPECTED FOR EARLY NEXT WEEK. && .DISCUSSION... 06Z NAM AND RUC MODEL DATA INDICATES RAPID DRYING LATER THIS AFTERNOON ALONG THE COAST THUS EXPECTING CURRENT SHOWER ACTIVITY TO TAPER OFF DRAMATICALLY LATE THIS MORNING OR EARLY THIS AFTERNOON. THE FRONTAL BOUNDARY THAT BROUGHT RAIN AND SNOW TO THE REGION YESTERDAY AND THIS MORNING MAY BE THE CABOOSE OF THIS WINTER/SPRING`S RAIN TRAIN...AS LONG TERM FORECAST MODELS DEPICT A MUCH WARMER AND DRIER PATTERN SHAPING AS WE HEAD INTO MAY. HIGH PRESSURE IS FORECAST TO BUILD OVER THE WEST BEGINNING ON MONDAY. A WEAK SHORTWAVE IS PROGGED TO MOVE ACROSS THE PACNW LATE TUESDAY AND WEDNESDAY...BUT IS EXPECTED TO ONLY BRING SOME LIGHT RAIN TO THE ORCA BORDER OR POSSIBLE DRIZZLE TO THE NORTH COAST. HIGH PRESSURE IS THEN FORECAST TO BUILD IN OVER THE WEST ONCE AGAIN LATE IN THE WORK WEEK WITH 583 DM 500 MB HEIGHTS FORECAST OVER THE EASTERN PACIFIC BY NEXT SATURDAY. && .AVIATION...SCT SHRA WILL DIMINISH IN COVERAGE ALONG THE COAST THIS AFTERNOON...ALTHOUGH INLAND AREAS WILL SEE SHOWERS CONTINUING THROUGH MUCH OF THE DAY. FLIGHT CONDITIONS WILL REMAIN PRIMARILY VFR ALTHOUGH OCCASIONAL MVFR CEILINGS/VISIBILITIES MAY OCCUR EARLY THIS MORNING AND IN HEAVIER SHOWERS. VFR CONDITIONS WITH CLEARING SKIES CAN BE ANTICIPATED TONIGHT. MAB && .MARINE...SEAS AND WINDS CONTINUE THEIR DOWNWARD TREND THIS MORNING...AND WILL CONTINUE TO DO SO FOR THE NEXT 12-24 HOURS. THUS THE GOING PACKAGE WILL REFLECT RELATIVELY SUBDUED CONDITIONS WITH NO ADVISORIES. LONGER PERIOD W SWELL WILL ARRIVE LATE TONIGHT/EARLY MONDAY WITH GRADUALLY BUILDING SEAS POSSIBLY WARRANTING SMALL CRAFT CRITERIA BY MONDAY. MAB NOTE...CDIP BUOY 46212 REMAINS OUT OF COMMISSION WITH NO ESTIMATED DATE OF REDEPLOYMENT. MAB && .EKA WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VISIT US AT WWW.WEATHER.GOV/EUREKA ca AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSONVILLE FL 958 AM EDT SUN APR 22 2007 .UPDATE...WATER VAPOR IMAGERY AND RUC GUIDANCE SHOW RIDGING OVER THE REGION WITH DRY AIR ALOFT. A STRONG SHORTWAVE WAS NOTED OVER THE CENTRAL PLAINS / UPPER MS VALLEY LIFTING NEWD. AT SFC...HIGH PRES HAS SHIFTED SE WITH A WEAKER PRES GRADIENT OVER THE S HALF OF ZONES SO WEAKER BOUNDARY LAYER WINDS ARE EXPECTED TODAY MAINLY OUT OF THE E AND SE. JAX SOUNDING SHOWS PWATS HAVE DROPPED SLIGHTLY SINCE YESTERDAY AND A STRONGER SUBSIDENCE INVERSION AND LITTLE LOWER AROUND 850 MB. STILL SUFFICIENT MOISTURE BELOW THE INVERSION TO GENERATE A HEALTHY CU FIELD LATER IN THE DAY. AS FAR AS THE WILD FIRE IN WARE COUNTY...SMOKE PLUME THIS MORNING IS ORIENTED SW-NE PER VIS IMAGERY PRESUMABLY DUE TO BACKED FLOW OVERNIGHT AS COASTAL TROUGH DEVELOPED. DEEPER ELY FLOW TODAY AS NOTED IN SOUNDING AND SLOW VEERING OF WINDS WILL ADVECT THE SMOKE TO THE W AND THEN NW. MINOR TWEAKS TO THE GRIDS FOR THIS AND WINDS. OTHERWISE...NO MAJOR CHANGES TO THE FORECAST WITH HIGHS FROM MID 70S COAST TO LOWER 80S INLAND. && .AVIATION...NO SIGNIFICANT ISSUES WITH BENIGN WX PATTERN AND SCT CU MAINLY AT NE FL TAF SITES. BRIEF CIGS POSSIBLE DUE SHOULD BE VFR ALL DAY. && .MARINE...BASED ON BUOY REPORTS AND GUIDANCE WILL LET THE ADVISORY EXPIRE AT OR BEFORE 11 AM. SEAS FROM 41012 ARE AROUND 5 FT AND 3-4 FT IN OUR SE GA WATERS. MAY BE ABLE TO TAKE DOWN SCEC IN NEAR SHORE WATERS AND GO WITH 3-5 FT. && .FIRE WEATHER...A CHALLENGING FIRE WX FORECAST AGAIN WITH MARGINAL RED FLAG FOR FL ZONES. BASED ON RECOMPUTED RH VALUES...RED FLAG WARNING IN OUR FL ZONES COULD BE EXPANDED BUT AM HESITANT TO DO THIS BASED ON YESTERDAY`S EVENT WHERE DEWPOINTS DID NOT DROP AS PREVIOUSLY THOUGHT. MORE SIGNIFICANT DROP IN DEWPOINTS IS LIKELY OVER SE GA. BASED ON COMBINATION OF LOW LEVEL MIXING AND MOS GUIDANCE SEEMS VERY POSSIBLE TO GET 4 HOURS LOW RH DURATION IN A FEW SE GA COUNTIES THIS AFTERNOON...SIMILAR TO SATURDAY. THEREFORE WILL LIKELY ISSUE A RED FLAG WARNING BEFORE NOON. && .PRELIMINARY POINT TEMPS/POPS... AMG 81 49 83 52 / 0 0 0 10 SSI 73 60 75 61 / 0 0 0 0 JAX 77 52 81 54 / 0 0 0 10 SGJ 75 57 78 59 / 0 0 0 0 GNV 81 50 84 54 / 0 0 0 10 OCF 82 50 83 53 / 0 0 0 10 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...RED FLAG WARNING FROM 1 PM TO 6 PM EDT THIS AFTERNOON FOR COLUMBIA-GILCHRIST-HAMILTON-SUWANNEE. FIRE WEATHER WATCH MONDAY AFTERNOON FOR ALACHUA-BAKER-BRADFORD- COLUMBIA-GILCHRIST-HAMILTON-MARION-SUWANNEE-UNION. GA...RED FLAG WARNING FROM 1 PM TO 6 PM EDT THIS AFTERNOON FOR APPLING-BACON-COFFEE-JEFF DAVIS. AM...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 AM EDT THIS MORNING FOR FERNANDINA BEACH TO ST AUGUSTINE FL 20 NM TO 60 NM OFFSHORE-ST AUGUSTINE TO FLAGLER BEACH FL 20 NM TO 60 NM OFFSHORE. && $$ SHASHY/MCALLISTER fl AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER TOPEKA KS 1008 AM CDT SUN APR 22 2007 .DISCUSSION... CHANGED THE TIMING OF THE WIND ADVISORY FOR THIS MORNING. CLOUDS HAVE CLEARED ACROSS THE WESTERN CWA AT MID MORNING. WINDS HAVE INCREASED RAPIDLY IN THIS AREA AND HAVE ALSO EXPANDED THE WIND ADVISORY WEST TO ABILENE AND NORTHEAST TO HOLTON FOR TODAY. THE UPPER LOW WAS NEAR KHLC WITH DRY SLOT WORKING ACROSS CENTRAL KANSAS. THE SURFACE LOW WAS NEAR HAYS THIS MORNING AND NEW RUC MOVES THE LOW INTO SOUTH CENTRAL NEBRASKA BY EARLY AFTERNOON. DRY LINE WILL BE PUSHING THROUGH THE CWA THROUGH THE AFTERNOON HOURS WITH BEST CONVECTIVE THREAT BETWEEN 18Z AND 22Z AS UPPER LOW MOVE NORTHEAST AND ERODES MID LEVEL CAP. MAIN CONCERN WILL BE ALONG THE NEBRASKA BORDER WHERE BEST LOW LEVEL SHEAR WILL BE THIS AFTERNOON. WE WILL BE LAUNCHING AN 18Z RAOB BALLOON TODAY. && .PREVIOUS DISCUSSION... THE 09Z WATER VAPOR SATELLITE IMAGERY SHOWED AN UPPER LEVEL LOW CENTERED OVER SOUTHEAST CO. A DRY INTRUSION AT 850-600MB WAS PUNCHING NORTHEAST INTO SOUTHWEST KS. A BROAD AREA OF SHOWERS AND ISOLATED THUNDERSTORMS CONTINUED TO WEAKEN AS THE SLOWLY ADVANCE NORTHEAST ACROSS CENTRAL KS. BOTH THE NAM AND THE GFS LIFT THE UPPER LOW NORTHEAST INTO EASTERN NE AND WESTERN IA BY EARLY THIS EVENING. THE BAND OF SHOWERS AND ISOLATED THUNDERSTORMS MAY HOLD TOGETHER AS THEY MOVE NORTHEAST ACROSS THE WESTERN AND CENTRAL COUNTIES THIS AFTERNOON. WE MAY SEE THE CLOUD COVER BREAK UP A BIT LATE THIS MORNING AND EARLY THIS AFTERNOON AS THE MID-LEVEL DRY SLOT MOVES NORTHEAST ACROSS EASTERN KS THIS AFTERNOON. IF WE GET SOME INSOLATION THIS AFTERNOON...SURFACE HEATING WILL CAUSE THE INSTABILITY TO INCREASE WITH MLCAPE APPROACHING 1000J/KG ACROSS THE CENTRAL AND EASTERN COUNTIES OF THE CWA. NAM FORECAST SOUNDINGS SHOW NO CAP THUS CONVERGENCE ALONG THE PACIFIC COLD FRONT...WHICH WILL BE MOVING EAST ACROSS THE CENTRAL AND EASTERN COUNTIES OF THE CWA THIS AFTERNOON WILL CAUSE SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS TO DEVELOP. INSTABILITY AND VERTICAL WINDSHEAR PROFILES WILL BE SUFFICIENT FOR THESE STORMS TO ROTATE. THE PRIMARY THREAT FROM ANY SUPERCELL THUNDERSTORMS WILL BE DAMAGING OUTFLOW WINDS AND LARGE HAIL. THE LOW-LEVEL WINDS FIELDS ARE FORECASTED TO REMAIN SOUTH TO SOUTHEASTERLY ACROSS NORTHEAST KS THIS AFTERNOON. THE ENHANCED LOW-LEVEL VERTICAL WINDSHEAR MAY CAUSE SUPERCELL THUNDERSTORMS THAT DEVELOP ACROSS THE NORTHEAST COUNTIES TO PRODUCE ISOLATED TORNADOES THIS AFTERNOON. AGAIN THE SEVERITY OF THESE STORMS WILL BE DEPENDENT ON THE AMOUNT OF SURFACE HEATING AHEAD OF THE PACIFIC COLD FRONT. IF WE HOLD ON TO THE CLOUD COVER THE INSTABILITY WILL BE REDUCED WHICH COULD KEEP MANY STORMS BELOW SEVERE LEVELS. HIGH TEMPERATES SHOULD WARM INTO THE LOWER TO MID 70S...ESPECIALLY IF WE SEE AFTERNOON SUNSHINE. 850MB WINDS ACROSS THE EASTERN COUNTIES ARE FORECASTED TO BE 40 TO 45 KTS FROM THE SOUTH AND SOUTHWEST. IF SKIES CLEAR THE BOUNDARY LAYER WILL MIX TO 850MB AND THE HIGHER MOMENTUM AIR PARCEL WILL MIX DOWN TOWARDS THE SURFACE. THIS WILL CAUSE SOUTHERLY SURFACE WINDS ACROSS EAST CENTRAL AND NORTHEAST KANSAS TO INCREASE AT OR ABOVE 30 MPH WITH GUSTS AS HIGH AS 45 MPH THIS AFTERNOON. THEREFORE I HAVE ISSUED A WIND ADVISORY FOR AREAS ALONG AND SOUTH OF A HERINGTON TO ALMA TO TOPEKA TO OSKALOOSA LINE. THIS EVENING THE PACIFIC COLD FRONT WILL MOVE EAST OF THE CWA...BRINGING AN END TO ANY THUNDERSTORM CHANCES. I KEPT 20 POPS ACROSS THE EXTREME EASTERN COUNTIES UNTIL 02Z. SKIES SHOULD CLEAR THROUGH THE NIGHT AS THE SURFACE WINDS VEER AROUND TO THE WEST AND DECREASE IN SPEED BELOW 15 MPH AFTER MIDNIGHT. LOWS WILL ONLY DROP INTO THE 50S. WE`LL BE BETWEEN UPPER LEVEL TROUGHS ON MONDAY AS SLIGHTLY DRIER AIR ADVECTS SOUTHEAST ACROSS THE CWA. HIGHS WILL BE IN THE LOWER TO MID 70S WITH MOSTLY SUNNY SKIES. THE NEXT 5H TROUGH LOOKS VERY INTENSE OFF THE OR AND CA COAST. THIS 5H TROUGH WILL DIG SOUTHEAST ACROSS THE DESERT SOUTHWEST ON MONDAY. A LEE SURFACE LOW WILL DEEPEN MONDAY NIGHT IN RESPONSE TO THE STRONGER SOUTHWEST FLOW ALOFT OVER THE ROCKY MOUNTAINS. DEEPER GULF MOISTURE WILL BE TRANSPORTED NORTH ACROSS WESTERN OK INTO WESTERN KS. WAA/ISENTROPIC LIFT ON THE EAST SIDE OF THE DEVELOPING MOIST AXIS WILL CAUSE SHOWERS AND THUNDERSTORMS TO DEVELOP ACROSS CENTRAL KS DURING THE EVENING HOURS OF MONDAY. THESE THUNDERSTORMS WILL MOVE NORTHEAST ACROSS THE CWA LATE MONDAY NIGHT. ON TUESDAY THE INTENSE 5H TROUGH WILL LIFT NORTHEAST INTO THE SOUTHERN HIGH PLAINS. THERE MAY BE A SEVERE THUNDERSTORM OUTBREAK TUESDAY AFTERNOON ACROSS SOUTHWEST AND CENTRAL KS...SOUTHWARD INTO NORTH TEXAS. DEEP GULF MOISTURE WILL BE IN PLACE WITH INCREASING VERTICAL WINDSHEAR IN THE WARM SECTOR AHEAD OF THE PACIFIC FRONT/DRYLINE. SUPERCELL THUNDERSTORMS WILL DEVELOP DURING THE AFTERNOON HOURS ALONG THE DRYLINE AND MOVE NORTHEAST. THE SCATTERED DISCRETE SUPERCELL THUNDERSTORMS WILL CONGEAL INTO AN MCS/SQUALL LINE THROUGH THE EVENING HOURS AND MOVE NORTHEAST ACROSS THE CWA. THERE IS A CHANCE THAT THESE STORMS MAY BE SEVERE WHEN THEY MOVE ACROSS THE CWA TUESDAY NIGHT. THE MAIN THREAT WILL BE DAMAGING STRAIGHT LINE WINDS AND LARGE HAIL. ELEVATED SEVERE THUNDERSTORMS MAY DEVELOP NORTH OF THE WARM FRONT DURING THE DAY ON TUESDAY WITH LARGE HAIL BEING THE PRIMARY THREAT. THE UPPER LOW WILL SLOWLY MOVE EAST ACROSS KANSAS WEDNESDAY AND WEDNESDAY NIGHT...KEEPING RAIN AND THUNDERSTORMS CHANCES ACROSS THE CWA THROUGH EARLY THURSDAY MORNING. HIGHS ON WEDNESDAY WILL BE COOLER WITH RAIN AND THUNDERSTORMS THROUGH THE DAY...ALSO COLDER AIR WILL BEGIN TO ADVECT SOUTHEAST ACROSS THE CWA BEHIND THE PACIFIC COLD FRONT. HIGH TEMPERATURES MAY BE WARMEST IN THE MORNING WITH TEMPERATURES IN THE LOWER 60S....WITH STEADY OR SLOWLY FALLING TEMPERATURES THROUGH THE DAY. SKIES SHOULD CLEAR FROM WEST TO EAST ACROSS THE CWA ON THURSDAY...THOUGH LOW-LEVEL CAA WILL KEEP HIGH TEMPERATURES IN THE MID TO UPPER 60S. FRIDAY LOOKS WARMER AS A 5H RIDGE MOVES EAST ACROSS THE PLAINS. HIGHS ON FRIDAY WILL WARM INTO THE LOWER TO MID 70S THE EXTENDED RANGE MODELS SHOW ANOTHER 5H TROUGH MOVING EAST TOWARDS THE CENTRAL AND SOUTHERN PLAINS ON SATURDAY PROVIDING A CHANCE OF SHOWERS AND THUNDERSTORMS FOR THE CWA. THE CURRENT EXTENDED RANGE FORECAST GRIDS LOOKED GOOD AND NO CHANGES WERE MADE. && .TOP WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY IN EFFECT THROUGH 700 PM CDT FOR AREAS ALONG AND SOUTH OF AN ABILENE TO MANHATTAN TO HOLTON LINE. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DODGE CITY KS 639 AM CDT SUN APR 22 2007 .AVIATION... VFR CONDITIONS CAN BE EXPECTED FOR THE NEXT 24 HOURS AT THE TERMINALS WITH CIGS GENERALLY IN THE 080 TO 100 RANGE. KHYS MAY SEE A PERIOD OF BORDERLINE MVFR CIGS DURING THE DAY TODAY, ALONG WITH A FEW SHOWERS AS THE UPPER LOW LIFTS OUT. THE MAIN STORY WILL BE THE WIND AS AN AREA OF LOW PRESSURE OVER SOUTHWEST KANSAS THIS MORNING MOVES EAST NORTHEAST ACROSS THE STATE TODAY. WINDS WILL VEER AROUND FROM SOUTHWEST TO NORTHWEST BY AFTERNOON AND WILL BE QUITE GUSTY IN THE 30 TO 40 KT RANGE. THE WINDS WILL BECOME LIGHT AND VARIABLE BY EVENING. && .PREV DISCUSSION... /ISSUED 312 AM CDT SUN APR 22 2007/ DISCUSSION... DAYS 1-2... FORECAST CHALLENGE WILL BE WHEN THE THUNDERSTORMS END ACROSS SOUTHWEST KANSAS THIS MORNING AND THEN THE CHANCE FOR THUNDERSTORMS LATE MONDAY AFTERNOON AND NIGHT. THE 00Z UPPER AIR ANALYSIS SHOWED A SIGNIFICANT UPPER LEVEL SHORTWAVE TROUGH LOCATED OVER THE CENTRAL AND SOUTHERN ROCKIES. THIS WAVE WAS LIFTING OUT ACROSS THE CENTRAL HIGH PLAINS EARLY THIS MORNING. THE MCS THAT IS LEFT OVER FROM THE SEVERE CONVECTION EARLIER IN THE EVENING HAD MOVED THROUGH MOST OF THE CWA. ANOTHER AREA OF THUNDERSTORMS HAD DEVELOPED OVER SOUTHEAST COLORADO UNDER THE UPPER SYSTEM. THIS AREA OF STORMS WAS PIVOTING OUT INTO WEST CENTRAL KANSAS. THE AREA OF THUNDERSTORMS WILL BE LIFTING OUT TO THE NORTHEAST THIS MORNING BUT THERE SHOULD BE SOME SCATTERED SHOWERS AND A FEW STORMS OVER THE NORTHWEST SECTIONS OF THE CWA FOR A TIME...SIMILAR TO WHAT IS FORECAST BY THE RUC. HAVE REORIENTED POPS IN THAT AREA BETWEEN 12 AND 18Z. AFTER THAT TIME, MODEL SOUNDINGS SHOW THE LOWER LEVELS MIXING OUT TO AROUND 700 MB WITH A SMALL POSITIVE AREA. COULD BE SOME SHOWERS REDEVELOPING THIS AFTERNOON AS A COLD POOL ALOFT MOVES OUT. DOUBT IF THERE WILL BE ANY SIGNIFICANT PRECIP WITH THESE SHOWERS SO THE SILENT POPS IN PLACE OUGHT TO HANDLE IT. ON MONDAY, THE NEXT SYSTEM WHICH IS NOW APPROACHING THE COAST OF NORTHERN CALIFORNIA WILL MOVE INTO THE SOUTHWESTERN CONUS WITH INCREASING SOUTHWESTERLY FLOW ALOFT OVER THE CENTRAL PLAINS. THE MODELS SHOW A WARM FRONT LOCATED ALONG OR JUST SOUTH OF THE KANSAS BORDER WITH A DRYLINE EXTENDING SOUTH INTO THE EASTERN TEXAS PANHANDLE MONDAY AFTERNOON. WHILE THERE IS SOME DISAGREEMENT ON EXACTLY WHERE THE SURFACE LOW WILL BE, THINK THAT THE BEST CHANCES FOR THUNDERSTORMS WILL BE OVER THE EASTERN AND NORTHERN PARTS OF THE CWA WHERE THE BETTER LOW LEVEL MOISTURE WILL BE RETURNING. HAVE REORIENTED POPS LATE MONDAY AFTERNOON AND NIGHT TO REFLECT THIS. THE GOING TEMPERATURE FORECAST LOOKED PRETTY GOOD WITH ONLY A FEW MINOR ADJUSTMENTS TO IT. DAYS 3-7... ACTIVE SPRING PATTERN WILL BE CONTINUING THROUGH THE EARLY PART OF THE UPCOMING WORK WEEK. THE NEXT IN A SERIES OF SYSTEMS TO AFFECT THE PLAINS WILL ARRIVE ON TUESDAY. BASED ON LATEST MODEL GUIDANCE FROM THE UKMET/GFS, THE SURFACE WARM FRONT SHOULD LIFT NORTH ACROSS THE CWA MONDAY NIGHT AND WILL RESIDE OVER NORTHERN KS ON TUESDAY. THE PACIFIC FRONT/DRYLINE WILL PUSH RAPIDLY EAST ACROSS WESTERN KS DURING THE DAY WITH A SMALL CHANCE OF STORMS AHEAD OF IT OVER MAINLY MY EASTERN TIER OF COUNTIES. THE BETTER RISK FOR SEVERE STORMS WILL MOST LIKELY BE EAST OF MY CWA BY TUESDAY AFTERNOON. THEN THE WRAP AROUND PRECIP ON THE COOL SIDE OF THE SYSTEM ENTERS THE WESTERN COUNTIES DURING THE AFTERNOON AND SWEEPS EAST ACROSS THE REMAINDER OF THE AREA TUESDAY NIGHT. POPS WILL BE GRADUALLY COMING TO AN END ON WEDNESDAY AS THE SYSTEM PULLS AWAY FROM WESTERN KS. DID NOT PULL POPS COMPLETELY AS THE UKMET STILL HAS THE UPPER LOW OVER NORTH CENTRAL KS ON WEDNESDAY. THE POP/WX GRIDS WERE TWEAKED TO FOLLOW ALONG WITH THE FORECAST REASONING. THE NEXT SYSTEM WILL MOVE INTO THE PLAINS TOWARD THE END OF THE WEEK BUT THE LATEST FORECASTS FROM THE UKMET/ECMWF/GFS ALL KEEP THE SYSTEM PROGRESSIVE AND NORTH OF KANSAS. OTHER THAN A FEW SHOWERS ALONG THE PACIFIC FRONT, THIS DOES NOT LOOK LIKE A BIG RAIN PRODUCER FOR MY CWA. THE SYSTEM WILL BE EAST OF US ON FRIDAY AND ALL THE NUMERICAL MODELS ARE IN AGREEMENT WITH THIS. WILL THEREFORE BACK OFF TO SILENT POPS DURING THIS PERIOD. ALSO MADE SOME TWEAKS TO THE TEMPERATURES ON TUESDAY AND WEDNESDAY. I TRENDED COOLER IN THE WEST ON TUESDAY AS THE COOL AIR ON THE BACKSIDE OF THE SYSTEM MOVES IN. ON WEDNESDAY, 850MB TEMPS SUPPORT HIGHS ONLY IN THE 50S OVER THE EAST AND 60S IN THE WEST WITH COOL SURFACE HIGH PRESSURE IN PLACE. HIGHS WERE THEREFORE LOWERED TO ACCOUNT FOR THIS. AVIATION... DISCUSSION WILL BE ISSUED FOLLOWING THE 12Z TAF ISSUANCE. && .PRELIMINARY POINT TEMPS/POPS... DDC 72 47 74 55 / 10 0 30 50 GCK 72 45 74 54 / 10 0 30 40 EHA 74 44 77 54 / 10 0 20 30 LBL 74 46 76 56 / 0 0 30 40 HYS 69 45 72 55 / 30 0 30 50 P28 74 51 76 60 / 10 0 40 50 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ FN02/27/27 ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SHREVEPORT LA 1059 AM CDT SUN APR 22 2007 .DISCUSSION... NARROW BAND OF SHOWERS WITH ISOLATED THUNDERSTORMS CONTINUES ALONG SFC-850MB THETA-E AXIS...AND ALONG THE TAIL END OF THE SHORTWAVE TROUGH EXTENDING FROM W AR NWD INTO MO TO THE PARENT CLOSED LOW NOW ENTERING E NE. BOTH THE NEW RUC AND 12Z NAM INITILIZED TOO FAR W WITH THESE FEATURES...THUS HAVE SPED UP POPS FOR SW AR AND REMOVED AFTERNOON MENTION. DID UP POPS TO LOW CHANCE FOR THE FAR N SW AR COUNTIES PER RADAR TRENDS...AND ASSUMPTION THAT TROUGH AXIS WILL GRADUALLY LIFT MORE NEWD THIS AFTERNOON WITH THE PARENT LOW. PLENTIFUL SFC-850MB MOISTURE NOTED ALONG THE S EXTENT OF THE THETA-E RIDGE OVER E TX/W LA...WILL BE SLOW TO LIFT WITH ADDITIONAL GULF INFLOW...BUT MAY GRADUALLY MIX OUT BY MID/LATE AFTERNOON. ALREADY NEARING LAKE WIND ADV. CRITERIA ACROSS WESTERN E TX...BUT ADDITIONAL CLOUD COVER DEVELOPING MAY LIMIT MIXING/POTENTIAL TO ONLY A SMALL AREA THROUGH THE AFTERNOON. OTHERWISE...ONLY MADE MINOR DOWNWARD TWEAKS IN FORECAST MAX TEMPS BASED ON 15Z OBS...AND INCREASED CLOUD COVER. UPDATE ALREADY OUT. 15 && .AVIATION... MIXTURE OF MVFR AND VFR CIGS LATE THIS MORNING WILL GIVE WAY TO SCT TO BKN CLOUDS AROUND 4 KFT BY 18Z. VSBYS...RESTRICTED BY HAZE IN THE 3 TO 5 MILE RANGE IN MANY AREAS WILL ALSO IMPROVE TO P6SM AS BRISK SOUTHERLY WINDS AROUND 15 KTS MIX AIR FROM ALOFT. ISOLATED TSTMS WILL BE CONFINED TO EXTREME NORTHERN AREAS IN SOUTHEAST OKLAHOMA AND SOUTHWEST ARKANSAS. ONLY TERMINALS TO HAVE ANY SHOWER OR TSTM ACTIVITY WITIN 25 MILES AFT 18Z TAF ISSUE WOULD BE TXK AND ELD... AND MAYBE SHV...BUT CHANCE TOO LOW TO MENTION. CONDITIONS SHOULD REMAIN VFR THROUGHOUT THE EVENING HOURS...BUT LOOK FOR A REPEAT OF MVFR CIGS AND VSBYS BEGINNING AROUND 23/07Z AND OCCASIONAL BRIEF IFR CIGS AND VSBYS BETWEEN 23/10Z AND 23/14Z. TERMINAL MOST LIKELY TO EXPERIENCE IFR...CIGS AND VSBYS...WILL BE LFK. SHV MAY REPEAT IFR CIGS. CONDS IMPROVING TO VFR AFT 23/16Z. SOUTHERLY WINDS THIS AFTERNOON IN THE 12 TO 16 KT SUSTAINED WITH GUSTS 20 TO 25 KTS WILL DIMINISH TO 10 KTS OR LESS BY 23/01Z. WINDS NOT AS STRONG MONDAY...WITH SOUTHERLY 10 TO 15 KTS EXPECTED. /14/ && .PRELIMINARY POINT TEMPS/POPS... SHV 82 63 84 65 / 10 10 10 20 MLU 81 61 82 64 / 0 0 10 10 DEQ 78 59 82 63 / 20 20 10 20 TXK 79 64 81 66 / 20 20 10 20 ELD 81 61 82 63 / 10 10 10 20 TYR 80 64 81 66 / 10 10 10 20 GGG 81 63 82 66 / 10 10 10 20 LFK 81 64 83 67 / 0 10 10 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 15/14 la AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE WAKEFIELD VA 1024 AM EDT SUN APR 22 2007 .SHORT TERM /REST OF TODAY/... FEW UPDATES TO FORECAST THIS MORNING. WITH SURFACE HI PRES IN PLACE THE FORECAST AREA WILL HAVE ANOTHER QUIET WARM SPRING DAY TODAY. MINOR TWEAKS TO TEMPS ACROSS THE AREA. NOT SO SURE DW PTS WILL DECREASE DRAMATICALLY TODAY AS YESTERDAY IN SW FLOW. KEPT DW PTS ON LOW END OF GUIDANCE THRU THIS EVENING. ZFPAKQ ALREADY OUT. && .PREV DISCUSSION... /ISSUED 329 AM EDT SUN APR 22 2007/ SHORT TERM /TODAY THROUGH MONDAY NIGHT/... SHORT TERM CHALLENGES WERE PRIMARILY IN REFINING TEMPERATURES. BROAD AREA OF HIGH PRESSURE CONTINUES TO DOMINATE OVER THE EASTERN CONUS...WITH CLOSEST RADAR ECHOES OF NOTE OVER THE PLAINS STATES. ANOTHER WARM/DRY AFTN...AS HIGH PRESSURE CONTINUES TO SLOWLY DRIFT SE...MOVING OFF CAROLINA COAST THIS AFTN. RAPIDLY RISING HEIGHTS THIS AFTN...AND WARM/DRY RETURN FLOW BY AFTERNOON...SUGGESTS L/M 80S EASILY ATTAINABLE FOR MOST OF CWA...TO AROUND 80 AT IMMEDIATE COAST AND OVER EASTERN SHORE. EXPECTING SEA BREEZE TO AGAIN PLAY A ROLE OVER COASTAL PLAIN THIS AFTN. ONCE AGAIN AGAINST IMMEDIATE COASTLINE WITH VRY LGT SYNOPTIC WNDS THIS AFTN. HV MADE SOME MINOR ADJUSTMENTS OVER THESE LOCATIONS TO REFLECT SLIGHTLY COOLER TEMPS BY MID TO LT AFTERNOON IVOF ORF/CPK/NCZ102. USED MAV/MET BLEND FOR TEMPERATURES THIS AFTN...AND TRENDED TOWARDS COOLER MAV GUIDANCE FOR TONIGHT WITH LTL/ANY DISCERNIBLE CLOUD COVER ALLOWING FOR ANOTHER GOOD RADIATING NGT. ANOTHER WARM/DRY DAY ON TAP FOR MONDAY...WITH M/U 80S LOOKING POSSIBLE FOR PIEDMONT AND CENTRAL VA (L/M 80S AT COAST) WITH ROBUST RETURN FLOW BY MONDAY AFTN. WENT CLOSER TO WARMER MAV GUIDANCE FOR HIGHS ON MONDAY. CLOUDS SLOWLY INCREASE BY MONDAY NGT/ERY TUESDAY AHEAD OF NEXT WEATHER MAKER. LONG TERM /TUESDAY THROUGH SATURDAY/... BIGGEST CHALLENGE IN EXTENDED WAS IN TIMING AND DETERMINING PCPN CHANCES FOR MID TO LATE WEEK. STILL GOOD MODEL AGREEMENT THAT FIRST FRONTAL SYSTEM WL REMAIN NORTH OF THE AREA....GENERALLY REMAINING ORIENTED FROM SOUTHERN NEW ENGLAND SOUTH INTO NORTHERN VA AND EXTENDING INTO THE OHIO VLY. 00Z/APR22 GFS DOES BRING BACKDOOR FRONTAL BNDRY A BIT FURTHER SOUTH THAN NAM. HOWEVER DO NOT SEE MUCH IN THE WAY OF FORCING THAT WOULD SUPPORT THIS SOLN ATTM. FOR NOW...WL PUSH FRONT AS FAR SOUTH AS FAR NORTHERN COUNTIES...RESULTING IN MOST OF THE AREA REMAINING DRY...AND REMAINING WITHIN WARM SECTOR. DUE TO THE PROXIMITY OF THE FRONT...WL INCREASE CLD COVER OVER THE NORTH AND KEEP SLIGHT CHANCE POPS FOR RIC-WAL AND NORTH FOR TUES NGT/WED. FUTURE SHIFTS WL BE ABLE TO ADJUST THIS AS NECESSARY. EITHER WAY...IT SHOULD BE NOTED THAT MEAGER AVAILABLE PCPN (PW VALUES REMAIN UNDERWHELMING) AND LACK OF ANY VIABLE CONVERGENCE CONTINUE TO BOLSTER BELIEF THAT ANY PCPN THAT DOES THREATEN THE AREA WL BE LGT AND VERY SMALL IN AREAL COVERAGE. FRONT DRIFTS BACK NORTH WEDNESDAY. AGREE WITH GOING FORECAST THAT A SIZABLE TEMPERATURE GRADIENT COULD EXIST BETWEEN NORTHERN AND SOUTHERN CWA...WITH LINGERING CLOUDINESS AND SCTD SHRAS HOLDING TEMPS BACK A BIT OVER NORTHERN SECTIONS. HOWEVER...KEPT TEMPS A LITTLE WARMER THAN MEX VALUES GIVEN LACK OF MODEL CONTINUITY OF LATE. NEXT...AND MORE LKLY PCPN THREAT COMES WITH A STRONGER FRONTAL PASSAGE THU NGT/FRI. LOW PRESSURE WL DEVELOP OVER THE MO VLY BY THU...TRACKING EASTWARD ALONG THE FRONTAL BOUNDARY. MODEL GUIDANCE CONTINUES TO KEEP BEST SLUG OF MOISTURE NORTH OF THE AREA. NONETHELESS...CONTINUING THE GOING CHC (30) POP FOR SHRAS/TSTMS AS H5 TROF PUSHES THROUGH ERY FRIDAY INTO FRI AFTN LKS GOOD. DRIER WX MOVES IN QUICKLY BEHIND THE FRONTAL BOUNDARY...AS WK HIGH PRESSURE PUSHES IN FROM THE SOUTHWEST. WL LEAVE FRIDAY NGT AND SATURDAY DRY FOR NOW. AVIATION /08Z-06Z/... VFR THRU PRD. WNDS BELOW 10 KTS. ONLY A FEW HIGH CLDS XPCTD. MARINE... NO FLAGS THRU MON AS HIGH PRS MOVES OFFSHORE. WNDS AOB 15 KTS. SEAS REMAIN IN THE 3-4 FT RANGE DUE TO RESIDUAL SWELL. DATA SUGGESTS OUR TYPICAL NOCTURNAL SPIKE IN SW WNDS MONDAY NIGHT INTO ERLY TUE...BUT WILL HOLD WNDS TO ARND 15 KT ATTM. BKDR FRNT NOW PROGGED TO ENTER NRN HALF OF MARINE AREA LATE TUE...TURNING WNDS INTO A E-SE DRCTN TUE NITE. FRNT THEN PROGGED TO LIFT BACK N AS A WRM FRNT WED...RESULTING IN SW WNDS ONCE AGAIN. FIRE WEATHER... LOW RH ONCE AGAIN TODAY. UTILIZED RUC/LOCAL WRF MODIFIED SOUNDING AND TRENDED RH/DEWPOINT WELL BELOW GUIDANCE...GIVEN POOR MODEL PERFORMANCE ON TD OF LATE. HOWEVER...EVEN WITH DRYING FUELS...LGT WNDS SHOULD DIMINISH ANY FIRE WEATHER CONCERNS CONSIDERABLY. EVEN STILL.. WL AGAIN MENTION DRY COND IN FWF...BUT WL HOLD OFF ON ANY STATEMENTS ATTM. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SHORT TERM...SMF md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 1119 AM CDT SUN APR 22 2007 .UPDATE... HAD TO UPDATE ONCE AGAIN TO INCREASE TEMPS EVEN HIGHER. AT 11 AM...READINGS AHEAD OF THE SFC FRONT WERE IN THE UPPER 60S AND LOWER 70S...ALREADY A FEW DEGREES ABOVE MOS/MAV GUIDANCE. IN CREASING CLOUDS IN THE NEXT FEW HOURS WILL HOLD TEMPS IN THE LOWER 70S THIS AFTERNOON. MEANWHILE...ON THE BACKSIDE OF THE FRONT 60S WILL PREVAIL. THIS INCREASED HEATING AND SLOWER PROGRESSION OF THE FRONT THIS MORNING WILL PLAY A SIGNIFICANT ROLE IN THE SEVERE WEATHER THREAT THIS AFTERNOON. CURRENTLY HAVE POOR CONFIDENCE IN MODEL CAPE/INSTABILITY VALUES THIS AFTERNOON...DUE TO WARMER SFC TEMPS THAN FCST...STALLED FRONT...AND POOR HANDLING OF YESTERDAY AND LAST NIGHTS DEVELOPMENT. SUSPECT RUC/NAM ARE UNDERESTIMATING INSTABILITY/CAPE THIS AFTERNOON. ALTHOUGH SFC DEW POINT DEPRESSIONS IN NW WIS ARE INCREASING AND RANGE 20 TO 25 DEGREE SPREADS. ELEVATED STORMS WITH LARGE HAIL AND DAMAGING WINDS WILL BE THE MAIN THREAT LATER THIS AFTERNOON AND EVENING. && .PREV DISCUSSION... /ISSUED 957 AM CDT SUN APR 22 2007/ UPDATE...ADJUSTED SKY COVER...TEMPS...AND MORNING POPS TODAY. CURRENT ASOS/RAWS OBSERVATIONS AND ANALYSIS PLACES THE SFC CYCLONE IN THE CENTRAL PLAINS...WITH A NEWRD EXTENDING FRONT POSITIONED THROUGH SW MN...NE INTO NC MN. VIS SAT IMAGERY SHOWS A LOW CLOUD DECK ALONG AND NORTH OF THE FRONT...WHILE MOSTLY SUNNY TO PARTLY CLOUDY SKIES ARE FOUND AHEAD OF IT. THE CLOUDS WILL INCREASE FROM NW TO SE AS THE FRONT PUSHES OVER THE NW HALF OF THE FA TODAY. INCREASED MAX TEMPS TODAY A FEW DEGREES IN WI ZONES WHERE THEY WILL SEE PLENTY OF SUN BEFORE THE FRONT ARRIVES THIS EVENING. TEMPS AT 9 AM IN NW WIS WERE ALREADY IN THE MID TO UPR 60S. ALTHOUGH THE SLIGHT RISK AREA DEFINED BY THE SPC WAS SHIFTED SOUTH AND OUT OF THE DLH CWA...MUCH OF THE NORTHLAND CAN STILL EXPECT TO SEE TSTMS THIS AFTERNOON AND EVENING...AND A FEW WILL HAVE THE POTENTIAL TO BECOME SEVERE. EARLY MORNING ACCUS SEEN NW OF DULUTH IMPLIES THERE IS INSTABILITY TO TAP LATER TODAY AS THE FRONT APPROACHES. ATTM...THE FAVORED TIME FRAME AND LOCATION FOR STORM DEVELOPMENT WILL BE BETWEEN 20Z AND 22Z...ALONG AND JUST AHEAD OF THE SFC FRONT. A STRONG SW MEAN WIND WILL RESULT IN NE TRACKING STORMS...ALL SHIFTING TO THE SE WITH THE FRONT. EXPECT THE TSTMS TO CONTINUE INTO THE EVENING HOURS...AND POTENTIALLY TRANSITIONING INTO HEAVY RAIN IN NW WISCONSIN LATE TONIGHT. PREV DISCUSSION... /ISSUED 348 AM CDT SUN APR 22 2007/ DISCUSSION...SHOWERS AND THUNDERSTORMS ACROSS MINNESOTA CONTINUE TO DECREASE IN COVERAGE AND INTENSITY EARLY THIS MORNING. HOWEVER THERE IS MORE RAIN APPROACHING OUR WRN ZONES FROM THE SOUTHWEST. THEREFORE WILL KEEP LIKELY POPS GOING ACROSS OUR WRN AND NRN ZONES THIS MORNING...WITH ONLY CHANCE POPS FARTHER SOUTHEAST. THE DECREASE IN PRECIPITATION MAY ALSO TRANSLATE TO A DECREASE IN CLOUD COVER THIS MORNING...ALLOWING FOR PARTIAL SUNSHINE AND IN TURN INCREASED SENSIBLE HEATING WHICH SHOULD HELP DESTABILIZE THE ATMOSPHERE BY THIS AFTERNOON. THE NAM HAS MUCAPE VALUES INCREASING TO BETWEEN 500-1000 J/KG...WHILE 0-3KM SRH VALUES WILL RANGE FROM 100 TO 200 M2/S2. THIS COMBINATION IS NOT SIGNIFICANT BY ANY MEANS...BUT IT SHOULD BE SUFFICIENT FOR THE REDEVELOPMENT OF SHOWERS AND THUNDERSTORMS ACROSS MUCH OF OUR FCST AREA THIS AFTERNOON AND EVENING...ALONG WITH ISOLATED SEVERE THUNDERSTORMS ACROSS THE SOUTHERN HALF OF OUR CWA. ALL OF THIS ACTIVITY WILL BE INITIATED BY A COLD FRONT THAT IS PROGGED TO TRACK EAST ACROSS OUR CWA TODAY AND THIS EVENING. IN ADDITION...THERE WILL ALSO BE LARGE SCALE ASCENT ASSOCIATED WITH AN UPPER LEVEL TROUGH PROPAGATING EAST ACROSS THE MIDWEST. THE FRONT SHOULD QUICKLY MOVE OVER NWRN WI BY EARLY THIS EVENING...THEN EXIT EAST OF OUR CWA BY MIDNIGHT TONIGHT. WITH THE LOSS OF DAYTIME HEATING...AND COOLING FROM THE PRECIP...INSTABILITY SHOULD DECREASE FAIRLY QUICKLY TONIGHT...DECREASING THE POTENTIAL FOR THUNDERSTORMS AND SEVERE WEATHER. BY MONDAY MORNING...ONLY SCATTERED SHOWERS SHOULD LINGER ACROSS NWRN WI AS THE FORCING MOVES WELL TO THE EAST...AND HIGH PRESSURE BUILDS SOUTH FROM CANADA. THE HIGH WILL LINGER OVER THE UPPER MIDWEST THROUGH MIDWEEK...RESULTING IN MAINLY DRY CONDITIONS FOR THE NORTHLAND. && POINT TEMPS/POPS... DLH 73 41 57 36 / 60 60 10 10 INL 61 36 56 30 / 50 10 10 10 BRD 71 41 60 37 / 70 50 10 10 HYR 76 46 62 35 / 40 70 20 10 ASX 74 44 57 35 / 50 70 20 10 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. $$ GRANING mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 935 AM EDT SUN APR 22 2007 .SYNOPSIS... 12Z SFC ANALYSIS SHOWS 1026 MB HIGH PRESSURE CENTERED OVER UPSTATE SC AND WESTERN NC. TEMPS ACROSS THE AREA WERE IN THE MID 50S TO LOWER 60S AND DEWPOINTS WERE IN THE LOWER/MID 40S. THE 12Z GSO SOUNDING WAS VERY DRY WITH A PWAT OF 0.33 INCHES AND DEWPOINTS OF 25-30F AS LOW AS 925-950 MB. && .SHORT TERM /REST OF TODAY/... FORECAST ON TRACK THIS AFTERNOON WITH CLEAR SKIES AND HIGH TEMPS IN THE LOWER 80S AS H5 RIDGE CONTINUES TO BUILD OVER THE MID-ATLANTIC AND SFC HIGH PRESSURE PASSES OVERHEAD AND TO THE S/SE BY EVENING. GIVEN THE AMOUNT OF DRY AIR IN THE 12Z GSO SOUNDING THIS MORNING AND WHAT HAPPENED YESTERDAY AFTERNOON WITH DEWPOINTS PLUNGING INTO THE MID 20S TO LOWER 30S BETWEEN 15-17Z OR SO...FEEL CONFIDENT IN SHOWING A SIMILAR TREND THIS AFTERNOON OF DEWPOINTS FALLING INTO THE LOWER 30S. THIS WILL YIELD MINIMUM RH VALUES AROUND 20% DURING THE AFTERNOON. LIGHT SOUTHWEST WINDS OF 7-12 MPH AT THE SFC AND ALOFT WILL PREVENT CRITICAL FIRE WEATHER CONDITIONS FROM BEING ATTAINED THIS AFTERNOON...HOWEVER...VERY DRY RH VALUES COMBINED WITH MIXING HEIGHTS OF UP TO 8000 FT WILL LIKELY CREATE ADVERSE CONDITIONS DURING PEAK DIURNAL HEATING/MIXING. -VINCENT && .PREV DISCUSSION... /ISSUED 640 AM EDT SUN APR 22 2007/ SHORT TERM /REST OF TODAY THROUGH MONDAY/... BASED ON TRENDS EVIDENT IN THE NEW 06Z NAM/GFS OF A STOUT AND GUSTY SOUTHWEST BREEZE MONDAY SUSTAINED AROUND 10 TO 20 MPH AND GUSTING TO AT LEAST 30 MPH... HAVE UPDATED GRAPHICAL AND TEXT PRODUCTS TO REFLECT THESE STRONGER WINDS TOMORROW. SEE FIRE WEATHER CONCERNS BELOW. -GIH AVIATION /12Z-12Z/... CONDITIONS WILL BE VFR. GFS MODEL SOUNDINGS SUGGEST SLIGHTLY COOLER TEMPERATURES BETWEEN 800MB AND 500MB CENTRAL AND EAST THIS AFTERNOON...WHICH WITH DIURNAL MIXING COULD RESULT IN A FEW CU IF THE SOUNDINGS NEAR KRDU AND KRWI VERIFY VERY CLOSE TO THE FORECAST. THE GFS SOUNDING APPEARS TO BE A LITTLE HIGH ON ITS SURFACE DEW POINT AND IF DEW POINTS ARE MUCH LOWER THERE WOULD BE COMPLETE BLUE AGAIN TODAY. FEW CU AT MOST WITH SURFACE WINDS 10KT OR LESS... VEERING TO THE WEST EARLY TODAY AND RETURNING TO SOUTH-TO-SOUTHWEST LATE...CONTINUING THIS EVENING. -DJF FIRE WEATHER... BASED ON THESE STRONG/GUSTY WINDS AND LOW RELATIVE HUMIDITY... THE STORM PREDICTION CENTER HAS OUTLOOKED THE REGION FOR NEAR-CRITICAL FIRE WEATHER CONDITIONS ON MONDAY. RH IS FORECAST TO BOTTOM OUT AT 30-35% MONDAY AFTERNOON. A FIRE DANGER STATEMENT OR FIRE WEATHER WATCH MAY BE NEEDED LATER TODAY FOR MONDAY... ESPECIALLY IF RH FORECASTS BEGIN TO TREND LOWER. SEE DISCUSSION BELOW FOR TODAY`S FIRE WEATHER ISSUES. -GIH PREV DISCUSSION... /ISSUED 325 AM EDT SUN APR 22 2007/ SHORT TERM /TODAY THROUGH TUESDAY NIGHT/... TODAY/TONIGHT: CONTINUED QUIET... GENERALLY CLOUD-FREE... DRY AND WARM WITH SURFACE HIGH PRESSURE AND HIGHLY AMPLIFIED MID LEVEL RIDGING OVERHEAD. APART FROM THE VERY WARM TEMPERATURES PEAKING IN THE 80-84 RANGE TODAY... OF NOTE WILL BE THE LOW RELATIVE HUMIDITY VALUES WITH EXPECTATIONS OF DEWPOINTS DROPPING WELL DOWN THROUGH THE 30S THIS AFTERNOON... AND POSSIBLE LOWER. SEE FIRE WEATHER DISCUSSION BELOW FOR MORE DETAILS. LOWS TONIGHT GENERALLY 46-51... BUT OUTLYING RURAL AREAS MAY SEE COOLER READINGS. MONDAY THROUGH TUESDAY NIGHT: THE SURFACE HIGH SHIFTS SLOWLY SOUTHEAST AND OFFSHORE STARTING THIS AFTERNOON... INTRODUCING STEADIER SOUTHWEST WINDS AND SLOWLY INCREASING THICKNESSES AND MOISTURE OVER CENTRAL NC. THIS MORNING`S MID LEVEL TROUGH AND SURFACE LOW OVER THE PLAINS WILL DAMPEN AS IT HEADS NORTHEAST THROUGH THE GREAT LAKES AND NEW ENGLAND THROUGH EARLY TUESDAY. THIS TROUGH HELPS TAMP DOWN THE MID LEVEL RIDGE OVER THE GULF OF MEXICO AND SOUTHEAST STATES... A BIT MORE PROFOUND ON THE NAM THAN THE GFS. AN 850 MB THETA-E RIDGE TO OUR WSW NOSES TOWARD WESTERN NC... AND MODELS SHOW A 40-50 KT LOW LEVEL JET ZIPPING ACROSS VA MONDAY NIGHT... HOWEVER THE WESTERLY-SHIFTING 850 MB WINDS SHOULD LIMIT MOISTURE EAST OF THE MOUNTAINS AND MOST OF THE LIFT IS TO OUR NORTH... SO WILL STAY DRY THROUGH MONDAY NIGHT BUT EXPECT INCREASING CLOUDS NW TO SE. HIGHS 80-84 MONDAY... FOLLOWED BY LOWS 53-56. THEN ON TUESDAY... THE FRONT BECOMES W-E ORIENTED TO OUR NORTH WITH MODELS DEVELOPING A SURFACE LOW OVER SOUTH CENTRAL VA LATE IN THE DAY. PRECIPITABLE WATER VALUES REMAIN HIGH ENOUGH... ABOUT 150% OF NORMAL... AND INCREASING INSTABILITY WITH CAPES RISING OVER 500 J/KG FAVORS AT LEAST A LOW CHANCE OF CONVECTION TUESDAY AFTERNOON/EVENING DESPITE A WARM POCKET IN THE MID LEVELS. HIGHS 80-83... WITH LOWS TUESDAY NIGHT 55-60 UNDER PARTLY TO MOSTLY CLOUDY SKIES. -GIH LONG TERM /WEDNESDAY THROUGH SATURDAY/... LITTLE CHANGE NEEDED. HAVE KEPT A SLIGHT CHANCE OF AN AFTERNOON OR EVENING STORM ACROSS THE NORTH WEDNESDAY GIVEN THE SURFACE LOW THAT THE GFS/ECMWF ZIP ACROSS NORTHERN VA LATE IN THE DAY AND THE TAIL END OF ITS WEAK SURFACE TROUGH THAT DRAGS ALONG THE NC/VA BORDER. HOWEVER WITH THE MID LEVEL SHORTWAVE RIDGING AHEAD OF THE SOUTHERN PLAINS TROUGH... ANY ACTIVITY SHOULD BE QUITE ISOLATED. THIS WAVE DAMPENS AS IT HEADS UP THROUGH THE OHIO VALLEY AND INTO THE NORTHEAST THROUGH FRIDAY. THE TRAILING COLD FRONT MOVES INTO THE NC MOUNTAINS LATE THURSDAY AND REALLY LOSES DEFINITION THROUGH FRIDAY... SO MUCH THAT LOW LEVEL THICKNESSES... WHICH REMAIN ABOVE NORMAL THROUGH THIS PERIOD... SHOW NO RESPONSE THROUGH FRIDAY. LARGE SCALE FORCING FOR LIFT WANES CONSIDERABLY... SO QPF MAY BE SORELY LIMITED IN OUR NECK OF THE WOODS... BUT HAVE KEPT CHANCE POPS THURSDAY AFTERNOON THROUGH FRIDAY MORNING. DRY THEREAFTER WITH THE CONSISTENT GFS SHOWING A DRY COLUMN AND STABILIZING MID LEVELS THROUGH SATURDAY. HIGHS IN THE MID 80S WEDNESDAY AND IN THE UPPER 70S TO AROUND 80 THURSDAY-SATURDAY WITH AN INCREASE IN CLOUD COVER. LOWS MOSTLY IN THE MID 50S TO LOWER 60S EACH MORNING. -GIH AVIATION /06Z-06Z/... DURING THE OVERNIGHT HOURS OF FRIDAY...RAPID EVENING COOLING OVER CENTRAL NORTH CAROLINA...COMBINED WITH SLIGHTLY HIGHER DEW POINTS AT THE TIME...RESULTED IN A BRIEF PERIOD OF MVFR-TO-IFR FOG AT KFAY AND KRWI. EARLY THIS MORNING...THE TEMPERATURE/DEW POINT SPREAD IS HIGHER...AND IN A FEW LOCATIONS THERE HAS BEEN JUST ENOUGH MIXING TO RESULT IN A LIGHT...BUT OBSERVED...WIND FROM THE SOUTHWEST. AROUND 06Z...SURFACE TEMPERATURES ACTUALLY ROSE AT KRWI. DEW POINTS ARE HIGHEST TOWARD THE EAST AND HAVE PROVIDED FOR A BRIEF PERIOD OF MVFR...LIGHT FOG AT KRWI...BUT ELSEWHERE ANTICIPATE VFR CONDITIONS. GFS MODEL SOUNDINGS SUGGEST SLIGHTLY COOLER TEMPERATURES BETWEEN 800MB AND 500MB CENTRAL AND EAST THIS AFTERNOON...WHICH WITH DIURNAL MIXING COULD RESULT IN A FEW CU IF THE SOUNDINGS NEAR KRDU AND KRWI VERIFY VERY CLOSE TO THE FORECAST. THE GFS SOUNDING APPEARS TO BE A LITTLE HIGH ON ITS SURFACE DEW POINT AND IF DEW POINTS ARE MUCH LOWER THERE WOULD BE COMPLETE BLUE AGAIN TODAY. FEW CU AT MOST WITH SURFACE WINDS 10KT OR LESS...VEERING TO THE WEST EARLY AND RETURNING TO SOUTH-TO-SOUTHWEST LATE. -DJF FIRE WEATHER... VISIBLE SATELLITE IMAGERY FROM YESTERDAY REVEALED FIRES BURNING IN HARNETT... CUMBERLAND... AND HOKE COUNTIES... AS RELATIVE HUMIDITY VALUES PLUMMETED TO 16-20% DURING THE AFTERNOON... MUCH LOWER THAN MOS GUIDANCE VALUES INDICATED. WHILE A LIGHT SOUTHWEST BREEZE MAY KEEP DEWPOINTS FROM CRASHING QUITE AS MUCH AS THEY DID YESTERDAY WHEN THE WINDS WERE LIGHTER AND VARIABLE... WITH NO CHANGE IN AIR MASS... ANOTHER STEEP DROP IN RELATIVE HUMIDITY VALUES IS EXPECTED TODAY. FORECAST DEWPOINTS WILL BE ABOUT 10 DEGREES BELOW MOS GUIDANCE VALUES... CLOSE TO THE NUMBERS ONE GETS WHEN THE LOWEST 100 MB ON THE MORNING RUC SOUNDING IS MIXED. THE LOWEST HUMIDITY SHOULD BE IN THE NORTHEAST CWA. THERE SHOULD BE A RAPID RECOVERY INTO THE 30-40% RANGE TOWARD SUNSET. WHILE WIND WILL NOT BE A MAJOR FIRE CONCERN WITH W TO SW SURFACE WINDS GENERALLY 5 TO 10 MPH AND FAIRLY LIGHT ALOFT... GIVEN THE FINE FUEL MOISTURE LEVELS THAT ARE DOWN TO ABOUT 3-5%... THESE DRY RH VALUES WILL NOT HELP THIS SITUATION. EXPECT MIXING HEIGHTS TODAY UP TO 8000 FT. -GIH/DJF && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT SHORT TERM...VINCENT nc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`S FIRE WEATHER ISSUES. -GIH && .PREV DISCUSSION... /ISSUED 325 AM EDT SUN APR 22 2007/ SHORT TERM /TODAY THROUGH TUESDAY NIGHT/... TODAY/TONIGHT: CONTINUED QUIET... GENERALLY CLOUD-FREE... DRY AND WARM WITH SURFACE HIGH PRESSURE AND HIGHLY AMPLIFIED MID LEVEL RIDGING OVERHEAD. APART FROM THE VERY WARM TEMPERATURES PEAKING IN THE 80-84 RANGE TODAY... OF NOTE WILL BE THE LOW RELATIVE HUMIDITY VALUES WITH EXPECTATIONS OF DEWPOINTS DROPPING WELL DOWN THROUGH THE 30S THIS AFTERNOON... AND POSSIBLE LOWER. SEE FIRE WEATHER DISCUSSION BELOW FOR MORE DETAILS. LOWS TONIGHT GENERALLY 46-51... BUT OUTLYING RURAL AREAS MAY SEE COOLER READINGS. MONDAY THROUGH TUESDAY NIGHT: THE SURFACE HIGH SHIFTS SLOWLY SOUTHEAST AND OFFSHORE STARTING THIS AFTERNOON... INTRODUCING STEADIER SOUTHWEST WINDS AND SLOWLY INCREASING THICKNESSES AND MOISTURE OVER CENTRAL NC. THIS MORNING`S MID LEVEL TROUGH AND SURFACE LOW OVER THE PLAINS WILL DAMPEN AS IT HEADS NORTHEAST THROUGH THE GREAT LAKES AND NEW ENGLAND THROUGH EARLY TUESDAY. THIS TROUGH HELPS TAMP DOWN THE MID LEVEL RIDGE OVER THE GULF OF MEXICO AND SOUTHEAST STATES... A BIT MORE PROFOUND ON THE NAM THAN THE GFS. AN 850 MB THETA-E RIDGE TO OUR WSW NOSES TOWARD WESTERN NC... AND MODELS SHOW A 40-50 KT LOW LEVEL JET ZIPPING ACROSS VA MONDAY NIGHT... HOWEVER THE WESTERLY-SHIFTING 850 MB WINDS SHOULD LIMIT MOISTURE EAST OF THE MOUNTAINS AND MOST OF THE LIFT IS TO OUR NORTH... SO WILL STAY DRY THROUGH MONDAY NIGHT BUT EXPECT INCREASING CLOUDS NW TO SE. HIGHS 80-84 MONDAY... FOLLOWED BY LOWS 53-56. THEN ON TUESDAY... THE FRONT BECOMES W-E ORIENTED TO OUR NORTH WITH MODELS DEVELOPING A SURFACE LOW OVER SOUTH CENTRAL VA LATE IN THE DAY. PRECIPITABLE WATER VALUES REMAIN HIGH ENOUGH... ABOUT 150% OF NORMAL... AND INCREASING INSTABILITY WITH CAPES RISING OVER 500 J/KG FAVORS AT LEAST A LOW CHANCE OF CONVECTION TUESDAY AFTERNOON/EVENING DESPITE A WARM POCKET IN THE MID LEVELS. HIGHS 80-83... WITH LOWS TUESDAY NIGHT 55-60 UNDER PARTLY TO MOSTLY CLOUDY SKIES. -GIH LONG TERM /WEDNESDAY THROUGH SATURDAY/... LITTLE CHANGE NEEDED. HAVE KEPT A SLIGHT CHANCE OF AN AFTERNOON OR EVENING STORM ACROSS THE NORTH WEDNESDAY GIVEN THE SURFACE LOW THAT THE GFS/ECMWF ZIP ACROSS NORTHERN VA LATE IN THE DAY AND THE TAIL END OF ITS WEAK SURFACE TROUGH THAT DRAGS ALONG THE NC/VA BORDER. HOWEVER WITH THE MID LEVEL SHORTWAVE RIDGING AHEAD OF THE SOUTHERN PLAINS TROUGH... ANY ACTIVITY SHOULD BE QUITE ISOLATED. THIS WAVE DAMPENS AS IT HEADS UP THROUGH THE OHIO VALLEY AND INTO THE NORTHEAST THROUGH FRIDAY. THE TRAILING COLD FRONT MOVES INTO THE NC MOUNTAINS LATE THURSDAY AND REALLY LOSES DEFINITION THROUGH FRIDAY... SO MUCH THAT LOW LEVEL THICKNESSES... WHICH REMAIN ABOVE NORMAL THROUGH THIS PERIOD... SHOW NO RESPONSE THROUGH FRIDAY. LARGE SCALE FORCING FOR LIFT WANES CONSIDERABLY... SO QPF MAY BE SORELY LIMITED IN OUR NECK OF THE WOODS... BUT HAVE KEPT CHANCE POPS THURSDAY AFTERNOON THROUGH FRIDAY MORNING. DRY THEREAFTER WITH THE CONSISTENT GFS SHOWING A DRY COLUMN AND STABILIZING MID LEVELS THROUGH SATURDAY. HIGHS IN THE MID 80S WEDNESDAY AND IN THE UPPER 70S TO AROUND 80 THURSDAY-SATURDAY WITH AN INCREASE IN CLOUD COVER. LOWS MOSTLY IN THE MID 50S TO LOWER 60S EACH MORNING. -GIH AVIATION /06Z-06Z/... DURING THE OVERNIGHT HOURS OF FRIDAY...RAPID EVENING COOLING OVER CENTRAL NORTH CAROLINA...COMBINED WITH SLIGHTLY HIGHER DEW POINTS AT THE TIME...RESULTED IN A BRIEF PERIOD OF MVFR-TO-IFR FOG AT KFAY AND KRWI. EARLY THIS MORNING...THE TEMPERATURE/DEW POINT SPREAD IS HIGHER...AND IN A FEW LOCATIONS THERE HAS BEEN JUST ENOUGH MIXING TO RESULT IN A LIGHT...BUT OBSERVED...WIND FROM THE SOUTHWEST. AROUND 06Z...SURFACE TEMPERATURES ACTUALLY ROSE AT KRWI. DEW POINTS ARE HIGHEST TOWARD THE EAST AND HAVE PROVIDED FOR A BRIEF PERIOD OF MVFR...LIGHT FOG AT KRWI...BUT ELSEWHERE ANTICIPATE VFR CONDITIONS. GFS MODEL SOUNDINGS SUGGEST SLIGHTLY COOLER TEMPERATURES BETWEEN 800MB AND 500MB CENTRAL AND EAST THIS AFTERNOON...WHICH WITH DIURNAL MIXING COULD RESULT IN A FEW CU IF THE SOUNDINGS NEAR KRDU AND KRWI VERIFY VERY CLOSE TO THE FORECAST. THE GFS SOUNDING APPEARS TO BE A LITTLE HIGH ON ITS SURFACE DEW POINT AND IF DEW POINTS ARE MUCH LOWER THERE WOULD BE COMPLETE BLUE AGAIN TODAY. FEW CU AT MOST WITH SURFACE WINDS 10KT OR LESS...VEERING TO THE WEST EARLY AND RETURNING TO SOUTH-TO-SOUTHWEST LATE. -DJF FIRE WEATHER... VISIBLE SATELLITE IMAGERY FROM YESTERDAY REVEALED FIRES BURNING IN HARNETT... CUMBERLAND... AND HOKE COUNTIES... AS RELATIVE HUMIDITY VALUES PLUMMETED TO 16-20% DURING THE AFTERNOON... MUCH LOWER THAN MOS GUIDANCE VALUES INDICATED. WHILE A LIGHT SOUTHWEST BREEZE MAY KEEP DEWPOINTS FROM CRASHING QUITE AS MUCH AS THEY DID YESTERDAY WHEN THE WINDS WERE LIGHTER AND VARIABLE... WITH NO CHANGE IN AIR MASS... ANOTHER STEEP DROP IN RELATIVE HUMIDITY VALUES IS EXPECTED TODAY. FORECAST DEWPOINTS WILL BE ABOUT 10 DEGREES BELOW MOS GUIDANCE VALUES... CLOSE TO THE NUMBERS ONE GETS WHEN THE LOWEST 100 MB ON THE MORNING RUC SOUNDING IS MIXED. THE LOWEST HUMIDITY SHOULD BE IN THE NORTHEAST CWA. THERE SHOULD BE A RAPID RECOVERY INTO THE 30-40% RANGE TOWARD SUNSET. WHILE WIND WILL NOT BE A MAJOR FIRE CONCERN WITH W TO SW SURFACE WINDS GENERALLY 5 TO 10 MPH AND FAIRLY LIGHT ALOFT... GIVEN THE FINE FUEL MOISTURE LEVELS THAT ARE DOWN TO ABOUT 3-5%... THESE DRY RH VALUES WILL NOT HELP THIS SITUATION. EXPECT MIXING HEIGHTS TODAY UP TO 8000 FT. -GIH/DJF && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...HARTFIELD AVIATION...DJF FIRE WEATHER...HARTFIELD nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 431 PM EDT SUN APR 22 2007 .SHORT TERM (TONIGHT AND MON)... MAIN FCST ISSUES ARE COVERAGE OF SHRA/TSRA TONIGHT AND TIMING THE ENDING OF PCPN MON. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A WELL-DEFINED SHORTWAVE LIFTING NE THRU THE CNTRL PLAINS...ACCOMPANIED BY SHRA/TSRA. AT THE SFC...LOW PRES WAS LOCATED OVER ERN NEBRASKA WITH A STATIONARY FRONT TRANSITIONING TO COLD FRONT EXTENDING NE TOWARD KDLH AND CYQT. WITH FORCING FROM SHORTWAVE SPREADING NE...SHRA/TSRA ARE DEVELOPING QUICKLY NE ALONG AND JUST BEHIND COLD FRONT. CLOSER TO HOME...AS EXPECTED...CRITICAL FIRE WX CONDITIONS HAVE MATERIALIZED THIS AFTN GENERALLY OVER THE W HALF OF UPPER MI. SFC DWPTS WERE SLOW TO FALL THRU EARLY AFTN...BUT ONCE MIXING BECAME SUFFICIENTLY DEEP TO TAP THE DRY AIR ALOFT INDICATED BY 12Z KGRB SOUNDING AND TAMDAR SOUNDINGS AT KSAW...DWPTS STARTED TO FALL. IN ADDITION...TEMPS HAVE RISEN SLIGHTLY HIGHER THAN ANTICIPATED. THUS...RH HAS DROPPED WELL DOWN INTO THE 20S. GUSTY WINDS ARE INCREASING THE CRITICAL FIRE WX CONDITIONS. APPROACHING SHORTWAVE WILL BEGIN TO SHEAR AND WEAKEN AS IT TRACKS INTO THE GREAT LAKES REGION TONIGHT. AT THE SAME TIME...COLD FRONT WILL BE MOVING ACROSS THE FCST AREA...REACHING THE W DURING THE EVENING AND EXITING THE E AROUND 12Z. ALTHOUGH FORCING WILL BE WEAKENING AND THERE IS ANTECEDENT DRY AIR TO OVERCOME...EXPECT FORCING TO BE SUFFICIENT TO FOCUS DECENT SHRA COVERAGE ALONG/BEHIND SHARP COLD FRONT TONIGHT. CONVERGENCE ALONG BOUNDARY IS QUITE STRONG WHICH INCREASES CONFIDENCE FOR WIDEPSREAD PCPN. AS FOR SVR THREAT... 0-3KM MUCAPE IS A FEW HUNDRED J/KG AT MOST. WHILE DEEP LAYER SHEAR IS SUFFICIENT (30-40KT) FOR ROTATING UPDRAFTS...LACK OF CAPE SUGGEST LITTLE/NO SVR THREAT. ON LAKE SUPERIOR...WILL NEED TO WATCH FOR A BRIEF PERIOD OF HIGH WINDS TO NEAR GALE FORCE AS SHARP WIND SHIFT CROSSES THE LAKE. NAM HAS 950MB WINDS INCREASING TO 40KT OVER THE E HALF OF LAKE SUPERIOR AND RUC13 SHOWS SFC WINDS JUST SHY OF GALES. ALTHOUGH PROFILE DOES NOT BECOME UNSTABLE OVER THE LAKE...LOW-LEVEL CAA IS FAIRLY IMPRESSIVE. HAVE BUMPED WINDS UP TO 30KT FOR NOW. INHERITED FCST LOOKED FINE FOR TIMING ENDING OF SHRA FROM W TO E MON MORNING INTO EARLY AFTN WITH DECREASING CLOUDS FOLLOWING. LOWERED TEMPS A BIT NEAR LAKE SUPERIOR E OF MARQUETTE AS A STIFF N TO NW WIND IS EXPECTED OVER THE E HALF OF THE LAKE. .LONG TERM (MONDAY NIGHT THROUGH SUNDAY)... FOR MONDAY NIGHT THROUGH TUESDAY NIGHT...ZONAL FLOW WILL TAKE OVER ALOFT WITH HIGH PRESSURE SINKING SOUTHEASTWARD FROM NORTHERN SASKATCHEWAN AND MANITOBA...ACROSS THE BORDER AND INTO TRI-STATE REGION. WITH THIS STRONG SURFACE HIGH OVERHEAD IT WILL REMAIN DIFFICULT FOR THE ALREADY WEAKENING SURFACE LOW ACROSS CENTRAL KANSAS BY 00Z WEDNESDAY...TO SURGE NORTHWARD AND INFLUENCE OUR ONGOING DRY WEATHER. UNLIKE OUR BRIEF GLIMPSE OF SUMMER LIKE TEMPERATURES...AFTERNOON HIGH TEMPERATURES WILL REMAIN NEAR CLIMATOLOGICAL NORMAL VALUES...IN THE LOWER 50S NORTH TO MID 50S SOUTH. AT 500MB THE 00Z CANADIAN RUN FOR THIS NEXT LOW TO CROSS THE CENTRAL PLAINS...WEDNESDAY INTO THURSDAY...LOOKS VERY SIMILAR TO THE CURRENT SYSTEM SITTING OVER SOUTHERN NEBRASKA. THIS ALSO IS A STRIKING COMPARISON TO THE 06Z RUN OF THE GFS FROM YESTERDAY. HOWEVER...WITH THE GFS HAVING GONE BACK TO A MORE SOUTHERLY TRACK AND CONSENSUS BACKING THIS UP...WILL DISCARD THE 00Z CANADIAN. THIS WILL CONTINUE TO MEAN A DRY FORECAST FOR THE ENTIRE UPPER PENINSULA. AT THIS TIME...RAIN IS EXPECTED TO STAY 50 OR SO MILES TO THE SOUTH OF MENOMINEE. AS FOR CLOSER TO THE WEEKEND...MODELS ARE HAVING A HARD TIME FIGURING OUT WHERE TO PLACE THE NEXT CUT OFF LOW OVER THE SOUTHWESTERN STATES. IT LOOKS LIKE THE LATEST RUNS HAVE PLACED IT ABOUT 500 MILES FURTHER SOUTHEAST...AND OVER THE BAJA REGION INSTEAD OF NORTHERN NEW MEXICO. THE 06Z GFS SEEMS TO BE THE SLOWEST OF THE MODELS WITH THIS FEATURE...WITH ITS 00Z RUN MORE OF A COMPROMISE BETWEEN THE MORE EASTWARD 00Z CANADIAN AND 00Z ECMWF. GENERALLY FOLLOWED HPC GUIDANCE FOR DAYS 3 THROUGH 7 (THURSDAY THROUGH SUNDAY)...WHICH WAS A COMPROMISE BETWEEN THE 00Z ECMWF AND 00Z GFS ENS MEAN. SOME MINOR CHANGES TO THE HPC GUIDANCE WAS TO LOWER POPS SLIGHTLY FOR THURSDAY NIGHT INTO FRIDAY MORNING...KEEPING OUR DRY FORECAST IN PLACE. AFTER THAT...HAVE PUT IN SLIGHT CHANCE TO LOW CHANCE POPS FOR THE WEAKENING COLD FRONT THAT WILL SLIDE OVER THE CWA FRIDAY NIGHT. HAVE ONLY A SHORT BREAK IN THE PRECIPITATION SATURDAY NIGHT BEFORE THE APPROACH OF THE NEXT FRONTAL SYSTEM...WITH THE SFC LOW CENTERED OVER NORTHERN MANITOBA BY 12Z SUNDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING MIZ004-005-010>012 UNTIL 8 PM EDT TODAY. && $$ ROLFSON (SHORT TERM) KF (LONG TERM) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1230 PM EDT SUN APR 22 2007 .UPDATE... WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A WELL-DEFINED SHORTWAVE LIFTING NE INTO THE CNTRL PLAINS...ACCOMPANIED BY SHRA/TSRA. CLOSER TO HOME...DRY AIRMASS COVERS MUCH OF WI/UPPER MI PER EARLY MORNING TAMDAR SOUNDING FROM KSAW AND 12Z KGRB SOUNDING. AMOUNT OF DRY AIR AVAILABLE TO MIX DOWN RAISES FIRE WX CONCERNS AS MIXING TO 800MB ON KGRB SOUNDING WOULD BRING SFC DWPTS DOWN TO THE MID 30S. WITH HIGHS NEARING 80F...RH WOULD FALL TO NEAR 20PCT. HOWEVER...ITS TOUGH TO DETERMINE IF DWPTS WILL FALL THAT FAR AS THERE IS A FAIRLY TIGHT MOISTURE GRADIENT OVER THE UPPER MIDWEST (NOTE THE MOIST PROFILE ON 12Z KMPX SOUNDING). APPROACHING SHORTWAVE SHOULD PLAY A ROLE AS SLIGHT BACKING OF LOW/MIDLEVEL WINDS AHEAD OF IT SHOULD HELP MAINTAIN THE DRY AIR OVER ERN WI INTO MUCH OF UPPER MI THIS AFTN. WITH SUSTAINED WINDS OF 15-20MPH...TEMPS RISING TO 75-80F OVER MUCH OF THE W HALF OF UPPER AND RH DROPPING TOWARD 25PCT...IT WILL BE A CRITICAL FIRE WX DAY...ESPECIALLY BTWN L`ANSE/MARQUETTE AND IRON RIVER/MENOMINEE. ELSEWHERE...TEMPS ALONG THE LAKESHORE E OF ESCANABA MAY NOT RISE ABOVE THE LWR 50S WITH A STIFF WIND OFF LAKE MICHIGAN. OVER THE FAR W...SLACKENING PRES GRADIENT NEAR APPROACHING COLD FRONT MAY ALLOW LAKE BREEZE TO DEVELOP LATE...RESULTING IN A SHARP TEMP DROP NEAR THE LAKE LATE IN THE AFTN. AS FOR PCPN...TRIMMED BACK EWD PROGRESS OF SHRA/TSRA INTO WRN UPPER MI LATE THIS AFTN BASED ON THE DRY AIR OVER THE AREA. AS COLD FRONT OVER NE MN MOVES INTO UPPER MI TONIGHT...BOUNDARY SHOULD PROVIDE A NICE FOCUSING MECHANISM FOR FORCING FROM SHORTWAVE TO ACT UPON... RESULTING IN DECENT PCPN COVERAGE. && .PREV DISCUSSION (ISSUED AT 355 AM EDT)... 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR RDG OVER THE GRT LKS BTWN LARGER SCALE TROFS OVER THE W AND IN THE WRN ATLANTIC. CWA DOMINATED BY SW FLOW BTWN HI PRES IN THE MID ATLANTIC STATES AND LO PRES TROF STRETCHING FM THE CNTRL PLAINS INTO MN ON THE ERN FLANK OF WRN TROF. ALTHOUGH 00Z GRB/MPX/APX SDNGS ARE QUITE DRY AND CAPPED...A FEW SHRA/TSRA NOTED OVER OVER THE MN ARROWHEAD AND INTO ERN LK SUP WHERE SHRTWV RUC SHOWS MOVING THRU NRN MN/ADJOINING ONTARIO IS INTERACTING WITH H85 WARM FNT ON THE NRN EDGE OF MID LVL CAPPING MARKED BY H7 TEMP ARND 2C. SKIES MOCLR TO THE S OF WARM FNT DESPITE STEEP H7-5 LAPSE RATES SHOWN ON THE 00Z MPX SDNG ABV H7 WARM NOSE/CAP. MORE WDSPRD CNVCTN HAS BROKEN OUT AS FAR E AS WRN MN ALG WARM FNT IN ADVANCE OF POTENT SHRTWV LIFTING OUT OF THE SRN ROCKIES. OTHER SHRTWVS ROTATING WITHIN WRN TROF ARE LOCATED OVER SRN SASKATCHEWAN AND JUST OFF THE CA COAST. MAIN FCST CONCERNS TDAY REVOLVE ARND DISPOSITION OF ONGOING CNVCTN FM THE MN ARROWHEAD INTO ERN LK SUP AND FIRE WX ISSUES. FOCUS FOR TNGT/MON SHIFTS TO SHRA/TSRA CHCS ASSOCIATED WITH SHRTWV NOW LIFTING OUT OF THE SRN ROCKIES. FOR EARLY THIS MRNG...RUC SHOWS SHRTWV HELPING TO INITIATE CNVCTN ALG H85 WARM FNT MOVING ENE THRU ONTARIO N OF LK SUP. MODEL SHOWS H85-5 QVECTOR CNVGC ASSOCIATED WITH DPVA AND WAD LINGERING OVER ERN LK SUP UNTIL ABOUT 09Z WHEN THE SYS IS PROGGED TO MOVE CLOSER TO JAMES BAY. ANOTHER ROUND OF DEEP LYR H85-3 QVECTOR CNVGC ASSOCIATED WITH ANOTHER SHRTWV PROGGED TO LIFT TOWARD WRN LK SUP BY 12Z. SO EXPECT CNVCTN OVER NE LK SUP TO DIMINISH BY FCST ISSUANCE...BUT WL MAINTAIN MENTION OF SCT TSRA OVER WRN LK SUP THIS MRNG. THIS NEXT SHRTWV FCST TO SLIDE NE INTO ONTARIO AS WELL BEFORE NEXT ROUND OF DEEP LYR H85-3 QVECTOR CNVGC AHEAD OF STRONGER SHRTWV FCST TO REACH IA BY 00Z MON ARRIVES LATER IN THE DAY. NAM/GFS FCST SDNGS INDICATE MID LVLS WL REMAIN SUFFICIENTLY CAPPED THRU MOST OF THE DAY TO KEEP LAND FA DRY EVEN THOUGH SCT SHRA/TSRA WL PERSIST OVER WRN LK SUP ON EDGE OF CAP AND CLOSER TO APRCHG COOL FNT ASSOCIATED WITH SHRTWV NOW IN SASKATCHEWAN. BULK OF MODELS GENERATE SOME LGT QPF OVER THE FAR WRN ZNS BY 00Z MON JUST IN ADVANCE OF THIS COLD FNT. CONSIDERING DRY NATURE OF LLVLS TO THE SW (MIXING TO H8 ON 00Z MPX SDNG WOULD YIELD SFC DWPT ARND 40...DVN SDNG IS EVEN DRIER) AS WELL AS ACYC H85 FLOW IN ADVANCE OF FNT...THINK GUIDANCE MAY BE A BIT TOO AGGRESSIVE AT SPITTING OUT PCPN EVEN OVER THE FAR W BEFORE 00Z AND COLD FROPA... ESPECIALLY SINCE BOTH MODELS PUSH SFC DWPTS INTO THE LOW 50S AT IWD BY 00Z. BUT SINCE GOING FCST HAS CHC POPS OVER THE FAR W AFT 21Z AND MODELS GENERATE SOME QPF...WL MAINTAIN LO CHC POPS FM CMX-IWD. AS FOR FIRE WX CONCERNS...MIXING TO H8-825 ON GFS/NAM FCST SDNGS WOULD SUPPORT HI TEMPS IN THE 75 TO 80 RANGE AWAY FM THE MODERATING INFLUENCE OF LK MI. LOOKING AT THE UPSTREAM MPX/DVN SDNGS...MODELS LOOK TOO AGGRESSIVE AT RETURNING LLVL MSTR AND PUSHING DWPTS AOA 50. IF DWPTS ARE 40 E TO 48 W...EXPECT RH TO DROP AS LO AS 25 TO 30 PCT AGAIN. WITH GUSTY WINDS LIKELY (NAM AND ESPECIALLY THE GFS SHOW MIXED LYR WINDS INCRSG TO 25 TO 35 KT)... FIRE WX PARAMETERS WL APRCH CRITICAL LVLS AGAIN TDAY. FOR TNGT...NAM/GFS DIVERGE ON FCST OF HANDLING OF SHRTWV IN IA AT 00Z MON...WITH GFS SHOWING SHRTWV MOVING TO JUST S OF GRB AT 12 MON WHILE NAM HOLDS SHRTWV BACK OVER NW IL. WITH SUPPORT FM THE MOST CONSISTENT 00Z UKMET (WHICH IS NCEP FVRD MODEL)...WL FOLLOW THE MORE SIMILAR GFS SCENARIO. MEANWHILE... GFS/UKMET FCST SHRTWV IN SASKATCHEWAN THIS PAST EVNG TO MOVE ACRS ONTARIO...WITH ACCOMPANYING SFC COLD FNT MOVING TO ABOUT P53-MNM BY 12Z MON. SINCE THESE SHRTWVS ARE FCST TO REMAIN OUT OF PHASE THRU THE NGT...GFS SHOWS TWO STRIPES OF HEAVIER PCPN. THE FIRST OF THESE IS OVER THE WRN ZNS DURING THE NGT DUE TO MORE SGNFT UPR DVGC IN RRQ OF UPR JET SUPPORTING ONTARIO SHRTWV AS WELL AS SHARP H85-7 FGEN BEHIND THE ASSOCIATED SFC FNT. GFS SHOWS THESE DYNAMICS TENDING TO SHIFT MORE NE DURING THE NGT...SO ITS HEAVIER QPF DOES NOT SPREAD E. THE UKMET ON THE OTHER HAND INDICATES THE SHARPER UPR DVGC/FGEN WL SPREAD FARTHER E...SO IT DRAGS HEAVIER PCPN INTO THE CNTRL ZNS BY 12Z. THE GFS ALSO FCSTS AN AXIS OF HEAVIER QPF ACRS THE SCNTRL ON THE CYC SIDE OF SHRTWV PASSAGE THRU WI AND WHERE INSTABILITY IS A BIT MORE IMPRESSIVE. CONCERNING SVR THREAT...OLD DAY 2 CONVECTIVE OUTLOOK HAD MUCH OF THE W HALF OF THE FA IN SLGT RISK. THINK BEST CHC OF SVR TSRA WOULD BE IN THE 00Z-06Z TIME FRAME ALONG AND JUST BEHIND COLD FROPA OVER THE W WHEN FCST 0-6KM BULK SHEAR NEAR 50KT WOULD BE BETTER PHASED WITH LOWER SSI FCST IN THE -2C TO -3C RANGE/STEEPER SFC-H8 LAPSE RATES THAT WOULD ALLOW MORE EFFICIENT TRANSFER OF GUSTY WINDS TO THE SFC. HOWEVER... MODIFIED GFS FCS SDNG FOR IWD AT 00Z FOR SFC T/TD 73/50 AND SOMEWHAT COOLER MID LVL TEMPS THAN EXPLICITLY FCST BY GFS YIELDS MO MORE THAN A FEW HUNDRED J/KG OF SFC BASED CAPE. ALTHOUGH WBZ FCST AT A FVRBL 9.5K FT...FCST MARGINAL LAPSE RATES WOULD HAVE A DIFFICULT TIME SUPPORTING LARGE HAIL. FCST LAPSE RATES/SHEAR PROGGED TO DIMINISH SGNFTLY AFT 06Z...SO ANY SVR THREAT SHOULD DIMINISH OVERNGT AS THE FNT PUSHES E. NOT SURPRISINGLY...THE NEW DAY1 CONVECTIVE OUTLOOK NO LONGER SHOWS THE FA IN THE SLGT RISK. SINCE NCEP INDICATES THE GFS BECOMES TOO FAST ON MON...TENDED TO FOLLOW THE UKMET FCST FOR FCST PREPARATION. AS PAIR OF SHRTWVS MOVE TO THE E...MODEL FCSTS COLD FROPA AT ERY BY 15Z...WITH LINGERING DEEP MSTR/SHARP H85-7 FGEN CLEARING THAT POINT BY 18Z. WL KEEP LINGERING HIER POPS OVER THE E HALF IN THE MRNG WITH POPS TO THE W DIMINISHING W-E AS COOLER AND DRIER AIR OVERSPREADS THE FA. SINCE UKMET IS SLOW TO LOWER H85 DWPT (SIMILAR TO OTHER MODELS)...SUSPECT THERE WL BE A GOOD AMT OF SC IN THE AFTN OVER AREAS INLAND FM THE STABILIZING INFLUENCE OF LK SUP. MUCH DRIER AIR LOOKS TO ARRIVE LATER IN THE DAY...SO EXPECT CLRG OF THE SC LATER WITH LOWERING SUN ANGLE. MON WL TURN OUT MUCH COOLER WITH UKMET SHOWING H85 TEMP LOWERING TO 2 TO 4C BY 00Z TUE. QUIET AND COOLER WX LOOKS ON TAP MON NGT THRU MOST OF THE REST OF THE WEEK AS CNDN HI PRES BLDS FM THE NW TERRITORIES INTO ONTARIO. NEXT SHRTWV NOW MOVING TOWARD CA LOOKS LIKE IT WL REMAIN WELL TO THE S AS IT MOVES E. JUST MINOR CHGS TO MESH BETTER WITH SURROUNDING OFFICES MADE TO GOING FCST. COORDINATED WITH GRB. && .MQT WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING MIZ004-005-010>012 UNTIL 8 PM EDT TODAY. && $$ ROLFSON (UPDATE) KC (PREV DISCUSSION) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 253 PM CDT SUN APR 22 2007 .DISCUSSION... 18Z WATER VAPOR SHOWS AN UPPER LEVEL LOW OVER ERN NE. SFC BOUNDARY ASSOCIATED WITH THIS SYSTEM EXTENDS FROM OVER LAKE SUPERIOR...THROUGH SE MINNESOTA...AND INTO ERN NE... WITH PRECIPITATION EXTENDING ALONG THIS BOUNDARY ON MN SIDE OF CWA. && .SHORT TERM (SUN NIGHT-WED) FORECAST FOCUS TONIGHT ON PRECIPITATION ENDING IN ERN HALF OF CWA. 12Z NAM SHOWING BACK EDGE OF PRECIPITATION BAND MOVING OUT OF SOUTHEASTERN CORNER OF CWA BETWEEN 00Z AND 03Z...WHILE RUC80 HOLDING ON UNTIL THE 03Z TO 06Z TIME FRAME. TENDING TOWARDS RUC SOLUTION AND KEEPING PRECIP IN UNTIL 06Z...WITH GENERALLY AROUND ONE TENTH OF AN INCH QPF...HOWEVER EXTREME SE CORNER COULD SEE AROUND ONE THIRD OF AN INCH THROUGH MIDNIGHT. NEXT FOCUS ON A WEAK WAVE CLIPPING THE NORTHWEST CORNER OF THE CWA ON TUESDAY. MODELS IN FAIRLY DECENT AGREEMENT WITH WEAK...MID LEVEL DISTURBANCE PASSING THROUGH SOUTHWESTERN MANITOBA TUE MORNING...AND WEAKENING AS IT ENTERS THE NW CORNER OF THE CWA ON TUE AFTERNOON. MODELS DO BRING WEAK QPFS INTO NORTHEASTERN NORTH DAKOTA...HOWEVER A SFC RIDGE IS PRGOGGED TO EXTEND DOWN FROM NRN MANITOBA ...AND NORTHEAST FLOW SHOULD KEEP THE LOWER LAYERS DRY. BUFKIT SOUNDINGS SHOWING A DRY LAYER BELOW 6000 FEET. EXPECT MID LEVEL CLOUDS WITH POSSIBLE VIRGA SHOWERS AT MOST AT THIS TIME. && .LONG TERM (THU-SUN)...SPLIT FLOW PATTERN TO TRANSITION TOWARDS WEAK ZONAL. MODELS AGREE PRETTY WELL ON A WEAK SYSTEM PASSING THROUGH ON THU WITH LIGHT HIT AND MISS PRECIP...OTHERWISE DRY AT LEAST TIL LATE SAT. LATE SAT INTO SUNDAY IS A BIGGER QUESTION AS 12Z GFS AND ECMWF DISAGREE WIDELY OVER AMPLIFYING ANOTHER 500 MB TROUGH...AGAIN INTO MB AND LOW POPS ARE APPLICABLE FARTHER SOUTH. NEAR OR SLIGHTLY ABOVE SEASONAL TEMPERATURES TO PERSIST THIS WEEK AS FLOW IS NOT EXPECTED TO AMPLIFY. && .AVIATION... VFR CONDITIONS EXPECTED THROUGH MON. HIGH SOIL MOISTURE AT FAR/BJI WILL BE OFF SET BY DRY ADVECTION AND A CONTINUING VERY LIGHT NORTH BREEZE. SO NO LOW CLOUDS/FOG EXPECTED TONIGHT. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ SPEICHER/GV nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPOKANE WA 244 PM PDT SUN APR 22 2007 .SYNOPSIS...HIGH PRESSURE WILL BUILD INTO THE PACIFIC NORTHWEST ON MONDAY BRINGING AN END TO THE COOL AND SHOWERY WEATHER. THE QUIET WEATHER WILL BE SHORT LIVED AS A COLD FRONT MOVES INTO THE REGION ON TUESDAY BRINGING ANOTHER CHANCE FOR RAIN SHOWERS. && .DISCUSSION... TONIGHT AND TOMORROW...A MESOSCALE LOW LEVEL CIRCULATION IS APPARENT IN THE VISIBLE SATELLITE IMAGERY OVER EASTERN WASHINGTON. COMPARING 21Z VAD WIND PROFILER DATA IN THE 850-700MB LAYER FROM KOTX AND KPDT ALSO SHOWS THIS SMALL SCALE FEATURE THAT HAS HELPED PRODUCE THE RAIN SHOWERS OVER THE EASTERN THIRD OF WASHINGTON TODAY. THIS SUBTLE FEATURE IS NOT STRONG DYNAMICALLY...BUT WITH A VERY MOIST ATMOSPHERE AND LAPSE RATES NEAR MOIST ADIABATIC...LITTLE LIFT IS NEEDED TO PRODUCE PRECIPITATION. THE RUC AND GFS SUGGEST THAT THIS SHALLOW FEATURE EXISTS...BUT DOESN`T EXACTLY HAVE THE SMALL SCALE RESOLUTION PEGGED. BOTH MODELS GRADUALLY MINOR THIS CIRCULATION OUT BETWEEN 00Z AND 06Z...SO A GRADUAL DECREASE IN SHOWERS CAN BE EXPECTED THIS EVENING...AND PERHAPS A SHIFT OF THE PRECIPITATION AXIS SOUTHWARD AS THE CIRCULATION IS ABSORBED BE THE LARGER UPPER LOW DIGGING INTO THE GREAT BASIN. THE MOISTURE LEFT BEHIND WILL NOT BE SCOURED OUT VERY EFFICIENTLY SINCE THE LOW LEVEL WIND FIELD WILL BE QUITE LIGHT TONIGHT. AS HIGH LEVEL MOISTURE MOVES EAST WITH THE BIGGER UPPER TROUGH...REDEVELOPMENT OF BROKEN STRATUS IS PROBABLE IN THE SPOKANE...PULLMAN...AND LEWISTON AREAS. LINGERING LOW CLOUDS WILL HAVE THE POTENTIAL TO HINDER OUR WARM UP OVER THE PANHANDLE AND FAR EASTERN WASHINGTON. LOW TO MID 60S ARE WHAT WE EXPECT FOR THE SPOKANE AND PULLMAN AREAS TOMORROW...BUT HIGHS COULD BE A BIT WARMER OR A BIT COOLER DEPENDING ON THE NATURE OF THE STRATUS TOMORROW. TUESDAY...THE NAM AND GFS HAVE BEEN FAIRLY CONSISTENT FORECASTING THE TIMING OF THE ARRIVAL OF THE UPPER LOW THAT IS MOVING OUT OF THE GULF OF ALASKA. PRECIPITABLE WATER VALUES ARE CURRENTLY IMPRESSIVE WITH VALUES EXCEEDING 1.25 INCHES...BUT THE COLD FRONT ASSOCIATED WITH THE APPROACHING TROUGH IS FORECAST TO UNDERGO SIGNIFICANT STRETCHING. BY THE TIME THE FRONT REACHES CENTRAL AND EASTERN WASHINGTON...THE LOWLANDS MAY BE HARD PRESSED TO GET MUCH MEASURABLE PRECIPITATION WITH THIS SYSTEM. SLIGHT CHANCES ALONG THE EAST SLOPES AND INTO THE COLUMBIA BASIN...WITH LOW CHANCES (30-40 PERCENT) FOR THE SPOKANE...PULLMAN...AND LEWISTON AREAS TUESDAY EVENING. /GKOCH WEDNESDAY THROUGH SUNDAY...MODELS TODAY ARE ONCE AGAIN IN RELATIVELY GOOD AGREEMENT...BUT AGAIN HAVING INITIALIZATION PROBLEMS OVER THE GULF OF ALASKA THAT MAY HAVE A BEARING ON THE EVENTUAL FORECAST EVOLUTION THROUGH THE NEXT WEEK. BOTH THE 12Z GFS AND ECMWF INITIALIZED THE SPRAWLING 500 MB LOW THERE MUCH MORE ACCURATELY THAN THE BULK OF THE GEFS MEMBERS AND THE GEFS MEAN...SO FORECAST WILL TREND HEAVILY TOWARD THE OPERATIONAL 12Z GFS AND ECMWF. HOWEVER...THE GENERAL PATTERN SUGGESTED THE LAST SEVERAL DAYS BY GUIDANCE SHOULD HOLD TRUE...THOUGH A FEW TIMING DIFFERENCES COME ABOUT FROM PREVIOUS RUNS...ESPECIALLY WITH THE GFS AND ECMWF WHICH TEND TO BE THE BETTER PERFORMING MEDIUM RANGE MODELS. THE BASIC PATTERN SUGGESTS THAT A BROAD UPPER TROUGH SHOULD BE NEARLY OVERHEAD BY WEDNESDAY. WITH 500 MB TEMPERATURES DROPPING TO AROUND -26C AND THETA-E LAPSE RATES BELOW 700 MB AT OR BELOW ZERO...WESTERLY FLOW OF AROUND 10 TO 15KTS INDICATED BY GFS AND NAM SHOULD HAVE A FAIRLY EAST TIME INTERACTING WITH TOPOGRAPHY TO CAUSE UPSLOPE OROGRAPHIC SHOWERS THROUGH THE DAY WEDNESDAY. GFS AND NAM SEEM TO PICK UP ON THIS VERY WELL IN THEIR QPF FIELDS WITH PRECIPITATION ALONG THE CASCADE RIDGES AND OVER THE NORTHEAST MOUNTAINS AND MOUNTAINS OF THE IDAHO PANHANDLE. HAVE ALSO ADDED SLIGHT CHANCE POPS ALONG THE WEST PLAINS AND PALOUSE GIVEN THE MORE GENTLE UPSLOPE FROM LOWER COLUMBIA BASIN WITH GENERAL FLOW WHICH MAY BE ENOUGH TO ALLOW A FEW SHOWERS TO POP WITH THE LOW LEVEL INSTABILITY NOTED ON THE MODELS. CONDITIONS QUICKLY QUIET DOWN WEDNESDAY NIGHT AS A RATHER SUBDUED RIDGE BEGINS TO BUILD INTO OUR AREA. TEMPERATURES LOOK TO START TO REBOUND SOME...BUT THE WINDOW WITH DECENT WARM ADVECTION IS NOT VERY SIGNIFICANT WITH THE 12Z RUNS TODAY. BY FRIDAY MORNING...THE NEXT SYSTEM LOOKS TO BE PUSHING MOISTURE TOWARD THE CASCADES WITH GOOD Q-CONVERGENCE BELOW 500 MB CROSSING THE NORTHERN 3/4THS OF THE CWA AND GFS INDICATING PRETTY GOOD ISENTROPIC OMEGAS IN THE 295 TO 305K LAYER WITH CONDENSATION PRESSURE DEFICITS FALLING DRASTICALLY AND QUICKLY BELOW 10 MB ON STRONG SOUTHWESTERLY MOISTURE TRANSPORT AT 300K. MODELS FAIL TO HAVE WARM FRONT TRAVERSE AREA ENOUGH WITH THE 12Z RUN TODAY TO GET US FULLY INTO THE WARM SECTOR...AND AS A RESULT BELIEVE THUNDER CHANCES ARE BASICALLY NIL WITH THIS SYSTEM...IN FACT THE FORECAST WILL BASICALLY JUST MENTION STRATIFORM PRECIPITATION ON MAINLY ISENTROPIC ASCENT. WITH A BRIEF INTERLUDE OF SOME COLDER MID-LEVEL AIR SKIRTING JUST NORTH OF THE AREA FRIDAY NIGHT...AND UPSLOPE FLOW PERSISTING BEHIND THE SYSTEM FROM FRIDAY...HAVE ADDED THE CHANCE OF SHOWERY POPS THROUGH FRIDAY NIGHT AS WELL GIVEN STRONG LAPSE RATES AND WIND FLOW. BY LATE SATURDAY AFTERNOON INTO THE BEGINNING OF NEXT WEEK...MODELS OTHER THAN THE DGEX REALLY START TO CRANK HEIGHTS UP OVER THE CWA. THE DGEX SOLUTION DOES INDICATE RIDGING BUILDING IN AS WELL...BUT IN A MUCH MORE SUBDUED FASHION THAN THE GFS AND ECMWF. UNFORTUNATELY THE OPERATIONAL CANADIAN GLOBAL ONLY GOES OUT 144 HRS...BUT CANADIAN GEM ENSEMBLES DO HINT AT A FAIR AMOUNT OF RIDGING BUILDING ALONG THE WEST COAST. HOWEVER...THE CANADIAN SEF ENSEMBLES ARE ALL OVER THE PLACE WITH THEIR SOLUTIONS. FOR THE MOMENT DUE TO CONTINUITY WITH PREVIOUS RUNS OF THE GFS AND ECMWF...THE WARMER SOLUTIONS SEEM MORE PLAUSIBLE. THE MODELS HAVE SLOWED DOWN ABOUT ONE DAY FROM THE 12Z RUNS YESTERDAY...BUT IT SEEMS BY SUNDAY AND DEFINITELY MONDAY NEXT WEEK...WE SHOULD BE IN FOR A STRONG WARMING TREND. /FRIES && .AVIATION... GRADUAL IMPROVEMENT IN CEILINGS IS EXPECTED BETWEEN 18Z AND 21Z IN THE SPOKANE VICINITY DESPITE THE PRESENCE OF AREAS OF RAIN. IFR CEILINGS SHOULD LIFT TO MVFR AS SLOWLY INCREASING TEMPERATURES THIS AFTERNOON BRING SLOW IMPROVEMENTS. A RETURN OF STRATUS IS LIKELY OVERNIGHT. TIMING ITS REDEVELOPMENT IS TOUGH SINCE THE MODELS FORECAST LITTLE TO NO LOW LEVEL FLOW TO EITHER SUGGEST UPSLOPE ENHANCEMENT OR DOWNSLOPE EROSION OF LOW CLOUD. THUS THE INTRODUCTION OF MVFR STRATUS AROUND 12Z IS NOT AN OVERLY CONFIDENT FORECAST. /GKOCH && .PRELIMINARY POINT TEMPS/POPS... SPOKANE 40 63 42 65 41 55 / 30 10 0 20 40 20 COEUR D`ALENE 40 63 42 65 41 56 / 20 10 10 20 50 20 PULLMAN 38 60 43 64 41 55 / 40 10 10 20 50 20 LEWISTON 46 65 44 70 47 59 / 40 10 10 10 40 10 COLVILLE 38 67 42 65 37 54 / 20 10 0 40 30 20 SANDPOINT 39 65 40 64 43 54 / 20 20 10 20 50 20 KELLOGG 39 61 40 63 41 54 / 30 20 10 20 50 30 MOSES LAKE 42 70 44 67 42 62 / 20 0 10 20 10 10 WENATCHEE 45 70 46 66 44 61 / 10 0 10 20 10 10 OMAK 39 70 42 65 37 60 / 10 0 10 30 10 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...NONE. WA...NONE. && $$ wa