AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PHOENIX AZ 1045 AM MST FRI AUG 15 2008 SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA FORECAST DISCUSSION .SYNOPSIS... A WEAK LOW PRESSURE SYSTEM FROM THE GULF OF CALIFORNIA AND A MOIST UNSTABLE AIRMASS OVER OUR AREA WILL CONTINUE AT LEAST A SLIGHT CHANCE OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS TODAY. ENOUGH MOISTURE WILL REMAIN FOR A SLIGHT CHANCE OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS IN SOUTHWEST AND SOUTH-CENTRAL ARIZONA THIS WEEKEND. DRIER AIR FROM THE WEST AND NORTH IS EXPECTED TO CONFINE THE POSSIBILITY OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS TO THE HIGHER TERRAIN EAST OF THE GREATER PHOENIX AREA DURING THE EARLY AND MIDDLE PARTS OF NEXT WEEK. LITTLE DAY TO DAY TEMPERATURE CHANGE IS EXPECTED WITH CLOSE TO AVERAGE TEMPERATURES FOR MID TO LATE AUGUST. && .DISCUSSION... SATELLITE SHOWS BAND OF MID AND HIGH CLOUDINESS DRAPED OVER NORTHEAST HALF OF FORECAST AREA. THIS IS MOISTURE REMAINING FROM LAST EVENINGS ACTIVITY AND INITIALIZED WELL WITH THE NAM AND RUC VORTICITY FIELD. BAND IS SLOWLY SLIPPING NORTH AND ERODING FROM THE SOUTH. QUESTION IS HOW MUCH EFFECT THIS WILL HAVE ON RISE OF TEMPERATURES THROUGH THE AFTERNOON. OBSERVATIONS THROUGHOUT THE SHROUDED REGION WERE SEVERAL DEGREES COOLER THAN THE SAME TIME YESTERDAY. IN OUR WESTERN ZONES READINGS HOWEVER WERE SEVERAL DEGREES WARMER THAN 24-HOURS AGO. THEREFORE...MADE SOME ADJUSTMENTS TO OUR MAX TEMPERATURES FOR THIS AFTERNOON TO BETTER HANDLE THE GRADIENT THAT WILL LIKELY DEVELOPMENT IN AFTERNOON HIGHS...ALONG WITH SOME SLIGHT CHANGES IN EXPECTED CLOUD COVER. FOCUS FOR STORM DEVELOPMENT TODAY LOOKS TO BE IN OUR WESTERN ZONES AS DISCUSSED IN THIS MORNINGS DISCUSSION...PRIMARILY IN CLIMATOLOGICALLY FAVORED REGIONS OF NORTHEAST YUMA AND EASTERN LA PAZ COUNTIES. SUFFICIENT MOISTURE AND INSTABILITY STILL EXISTS IN THE EASTERN HALF OF THE FORECAST AREA...AS EVIDENCED BY THE 1.64 INCHES OF PWAT AND GREATER THAN 2000 J/KG CAPE ON THE MORNING KPSR SOUNDING. THIS AMS HOWEVER WAS WORKED OVER PRETTY GOOD LAST NIGHT AND GENERALLY SPEAKING THE DAY AFTER SUCH ACTIVITY IS LESS ACTIVE. STORMS THAT DO DEVELOP OVER THE HIGHER TERRAIN...HOWEVER COULD PROPAGATE INTO THE LOWER DESERTS. STEERING FLOW HOWEVER IS EAST TO SOUTHEAST...NOT THE MOST FAVORABLE FOR BRINGING STORMS INTO THE GREATER PHOENIX AREA. WESTERN ZONES HOWEVER HAVE LESS CLOUDINESS...AND SEVERAL SHORT RANGE MODELS...INCLUDING OUR LOCAL WRF BRING SOME ENERGY NORTH FROM THE GULF OF CALIFORNIA INTO SOUTHWEST ARIZONA. THIS SEEMS TO BE ASSOCIATED WITH AN UPPER LEVEL LOW OR INVERTED TROUGH. HARD...HOWEVER...TO PICK THIS FEATURE UP ON SATELLITE. DID RAISE POPS SLIGHTLY FOR ZONES 26 AND 21...AS ALL MODELS SEEMED TO INDICATE THIS WAS THE REGION WITH THE GREATEST THREAT. WILL REEVALUATE AGAIN PRIOR TO ISSUING MY AFTERNOON PACKAGE. .PREV DISCUSSION... ISSUED AT 545 AM MST FRI AUG 15 2008 ISOLATED SHOWERS AND THUNDERSTORMS OVER SOUTHWEST MARICOPA COUNTY AND LA PAZ COUNTY DISSIPATED BEFORE MIDNIGHT LAST NIGHT. AN AREA OF CLOUDINESS WAS LEFT OVER FROM SOUTH-CENTRAL ARIZONA INCLUDING THE GREATER PHOENIX AREA WEST-NORTHWEST ACROSS LA PAZ COUNTY AND RIVERSIDE COUNTY. TEMPERATURES WERE GENERALLY 1 TO 5 DEGREES COOLER BEFORE SUNRISE THIS MORNING COMPARED WITH THE SAME TIME YESTERDAY. A WEAK LOW PRESSURE SYSTEM WAS LOCATED OVER FAR NORTHWEST MEXICO IN THE VICINITY OF THE NORTHERN GULF OF CALIFORNIA EARLY THIS MORNING. THIS LOW PRESSURE SYSTEM IS EXPECTED TO MOVE SLOWLY NORTH INTO SOUTHWEST ARIZONA THIS AFTERNOON. THE LOW PRESSURE SYSTEM AND MOIST UNSTABLE AIRMASS STILL OVER OUR AREA MEANS AT LEAST A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND THIS EVENING. THE BEST CHANCE OF SHOWERS AND THUNDERSTORMS IS ON THE NORTH SIDE OF THE LOW IN LA PAZ COUNTY TO NORTHERN YUMA COUNTY...AND OVER THE HIGHER TERRAIN EAST OF PHOENIX. ENOUGH MOISTURE WILL REMAIN FOR A SLIGHT CHANCE OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS IN NORTHERN YUMA COUNTY...LA PAZ COUNTY AND SOUTH-CENTRAL ARIZONA THIS WEEKEND. AT THAT TIME...AN UNUSUALLY STRONG LOW PRESSURE SYSTEM FOR THIS TIME OF YEAR WILL MOVE SLOWLY SOUTHEAST OVER COLORADO. THE TRAILING SOUTHWEST END OF THIS SYSTEM IS EXPECTED TO AFFECT SOUTH-CENTRAL ARIZONA MAINLY OVER THE HIGHER TERRAIN EAST OF PHOENIX. A HIGH PRESSURE CENTER WILL BE LOCATED JUST OFF THE NORTHERN BAJA CALIFORNIA COAST DURING THE EARLY AND MIDDLE PARTS OF NEXT WEEK. THERE IS A LINGERING SLIGHT CHANCE OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS IN THE HIGHER TERRAIN EAST OF THE GREATER PHOENIX AREA DURING THE EARLY AND MIDDLE PARTS OF NEXT WEEK. OTHERWISE... DRIER AIR FROM THE WEST AND NORTH...MOVING OVER OUR AREA IN THE CLOCKWISE FLOW AROUND THE HIGH...IS EXPECTED TO RESULT IN MOSTLY CLEAR NIGHTS AND SUNNY DAYS DURING THE EARLY AND MIDDLE PARTS OF NEXT WEEK WITH TEMPERATURES NEAR AVERAGE FOR MID TO LATE AUGUST. && .AVIATION... AFTER LAST EVENINGS CONVECTIVE ACTIVITY THE AIRMASS HAS COOLED OFF CONSIDERABLY AND STABILIZED. SCT-BKN CLOUDS AT OR ABOVE 10 THSD FEET REMAINS. BY 1900 TO 2100Z SUFFICIENT HEATING AND AMPLE MOISTURE BELOW 15 THSD FT WILL GENERATE FEW CB TYPES AT ALL AIRFIELDS. CANNOT RULE OUT A STRAY TSTM OR TWO SPCLY INVOF YUMA THIS MORNING...BUT NOT NEARLY AS BUSY AS THURSDAY MORNING WHEN OUTFLOW BOUNDARY HELPED TRIGGER THOSE STORMS. FOR THE WEEKEND...MODELS INSIST ON A STRONGER WESTERLY FLOW ALOFT FOR MOST AIRFIELDS. HOWEVER...WITH ENOUGH LOW LEVEL MOISTURE AND GOOD HEATING...LOOK FOR A SLIGHT CHANCE OF A SHOWER OR TSTM IN THE AFTERNOONS/EVENINGS BOTH DAYS. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... NO LARGE CHANGES IN THE HUMIDITY TODAY OR SATURDAY...EXCEPT A BIT DRIER AIR WILL MOVE INTO CALIF ZONE 230 BY TONIGHT. THUS...WITH SUFFICIENT HEATING AND PLENTY OF MOISTURE...EXPECT A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS SOUTH CENTRAL ARIZONA THROUGH SUNDAY. A HIGH PRESSURE SYSTEM PUSH DRIER AIR INTO THE REGION NEXT WEEK FOR A RETURN TO MORE SUNSHINE IN ALL FIRE WEATHER ZONES FOR TUESDAY THROUGH THURSDAY. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...NONE. CA...NONE. && $$ NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT WEATHER.GOV/PHOENIX DISCUSSION...MCLANE/ELLIS AVIATION...SIPPLE FIRE WEATHER...SIPPLE az AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN DIEGO CA 1045 AM PDT FRI AUG 15 2008 .SYNOPSIS...THE AIR MASS REMAINS MOIST AND UNSTABLE ENOUGH FOR THUNDERSTORMS OVER THE MOUNTAINS AND DESERTS TODAY. A FLASH FLOOD WATCH IS IN EFFECT FOR THE DESERTS THIS AFTERNOON AND EVENING. THE AIR MASS WILL SLOWLY DRY AND STABLIZE OVER THE WEEKEND SO LESS THUNDERSTORMS ARE EXPECTED FOR SATURDAY AND ONLY ISOLATED THUNDERSTORMS ON SUNDAY. THE MARINE LAYER WILL REMAIN AROUND 1500 FEET DEEP AND THIS WILL PRODUCE NIGHT AND MORNING CLOUDS OVER THE COASTS AND WESTERN VALLEYS. COOLER TEMPERATURES ARE FORECAST FOR NEXT WEEK AS A TROUGH OF LOW PRESSURE SETS UP ALONG THE COAST. THIS SHOULD ALSO DEEPEN THE MARINE LAYER AND SPREAD CLOUDS FURTHER INLAND EACH NIGHT. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... .SHORT TERM...TODAY THROUGH SUNDAY BOOMERANG SHAPED HIGH AT 500 MB WITH RIDGE AXIS ARCING FROM MONTANA TO CALIFORNIA TO SONORA MEXICO TO CONTINUE THROUGH THIS PERIOD BUT SLOWLY WEAKEN. THE SHORT WAVE TROUGH/REMNANT CIRCULATION ASSOCIATED WITH MESOSCALE CONVECTIVE COMPLEX THAT MOVED ACROSS SOUTHWEST CALIFORNIA YESTERDAY CONTINUES TO ROTATE UP AND AROUND THE WESTERN EDGE OF THE RIDGE AND IS CURRENTLY MOVING NORTH ALONG THE CENTRAL CALIFORNIA COAST. THE AIR MASS LEFT IN ITS WAKE OVER SOUTHWEST CALIFORNIA IS MOIST AND UNSTABLE. USING THE SAME MODELS AND FIELDS AS YESTERDAY TO DETERMINE MOST LIKELY AREAS OF CONVECTION IN THE NEAR TERM...THE RUC13 AND NAM12 MODELS...925-850 MB STREAMLINES...850-500 MB OMEGA...AND 300-200 MB DIVERGENCE...THESE SHOWED FOCUS OVER IMPERIAL AND EASTERN RIVERSIDE COUNTY UNTIL 1100 PDT THEN SHIFTING WEST AND NW BY NOON TO 10000 FOOT RIDGE OF SAN BERNARDINO MOUNTAINS AND SAN JACINTO MOUNTAINS...THEN EXTENDING SOUTHWARD BETWEEN NOON AND 1400 PDT TO THE SANTA ROSA MOUNTAINS AND LAGUNA MOUNTAINS...AND THEN DURING THE MID TO LATE AFTERNOON SHIFTING EASTWARD ACROSS JOHNSON VALLEY...COACHELLA VALLEY...AND ANZA BORREGO DESERT. QPF AMOUNTS PER THE MODELS WERE INDICATING A QUARTER TO A HALF INCH. PRECIPITABLE WATER VALUES PER SOUNDINGS AT MIRAMAR AND YUMA ARE SIMILAR TO YESTERDAY...AROUND 1.4 INCHES. NO STRONG STEERING WINDS TO MOVE STORM CELLS OUT QUICKLY SO 1.5 INCHES IS A GOOD FIRST GUESS FOR MAXIMUM QPF FOR ANY ONE LOCATION...UNLESS MORE THAN ONE CELL PARKS OVER THE SAME AREA. THIS LATTER SCENARIO IS LESS LIKELY AS THERE IS STILL SOME MID AND UPPER LEVEL STABILITY FROM PRESSURE REBOUNDING IN THE WAKE OF THE SHORT WAVE TROUGH MENTIONED ABOVE THAT WILL CAP THE CONVECTION TO AROUND 25000 FEET UNTIL MID AFTERNOON. HOWEVER DO EXPECT PULSE TYPE THUNDERSTORMS...SIMILAR TO LAST FRIDAY...FROM 1400-1800 PDT WITH HEAVY RAINFALL RATES AND LITTLE MOVEMENT. THIS ALL ADDS UP TO INCREASED FLASH FLOOD THREAT FOR DRY WASHES AND CREEKS COMING OUT OF THE MOUNTAINS AND FLOWING INTO THE DESERT AREAS. ADDED A COUPLE OF HOURS TO THE ABOVE TIMES TO ACCOUNT FOR LINGERING RUNOFF MAKING ITS WAY DOWNSTREAM. UPDATED GRIDS AND FORECAST PRODUCTS ALREADY TO REFLECT THIS THINKING. CONVECTION SHOULD SHUT DOWN FAIRLY QUICKLY THIS EVENING AND FOR SATURDAY BE MAINLY OVER THE SAN BERNARDINO AND SAN JACINTO MOUNTAINS AND THEN MOVE OFF ACROSS JOHNSON/COACHELLA VALLEYS. AREAL RAINFALL AMOUNTS OF A TENTH OF AN INCH OR LESS EXPECTED THEN ALTHOUGH CAN NOT TOTALLY RULE OUT THE ROGUE CELL. HOWEVER TRANSPORT WINDS PICK UP OUT OF THE SOUTHWEST SO THIS WOULD BE A LOW THREAT. FOR SUNDAY EVEN LESS COVERAGE BUT AIR MASS NOT TOTALLY DRIED OUT AND AS MENTIONED ABOVE THE UPPER LEVEL RIDGE IS WEAKENING SO THE DIURNAL HEATING OVER THE HIGHEST PEAKS SHOULD BE STRONG AND LONG ENOUGH TO OVERCOME THE SUBSIDENCE ALOFT. HAVING NOW DEALT WITH THE CONVECTIVE THREAT FOCUS TURNS TOWARDS WHERE MOST OF THE POPULATION LIVES...HAVE KEPT THE MARINE LAYER AT OR BELOW 1500 FEET THROUGH THE WEEKEND. BROKEN TO OVERCAST STRATUS CLOUDS LIKELY TO AFFECT THE COAST BETWEEN 2000-1000 PDT EACH NIGHT/DAY AND INLAND AREAS BETWEEN 2300-0700 PDT. NAM12 MODEL CROSS SECTIONS SHOWING RH AT 100 PERCENT BETWEEN 200 AND 1000 FEET ELEVATIONS SATURDAY NIGHT/SUNDAY MORNING INDICATE THE POSSIBILTY OF DENSE FOG FOR THE COASTAL MESAS AND LOWER WESTERN VALLEYS. .LONG TERM...MONDAY THROUGH NEXT FRIDAY... COOLING TREND AS A TROUGH MOVES OVER PACIFIC NORTHWEST REGION AND HIGH PRESSURE RIDGE IS FLATTENED AND PUSHED SOUTH OF CALIFORNIA. FROM PREVIOUS DISCUSSION THIS RESULTS IN...DRY WEST TO SOUTHWEST FLOW ALOFT...A MARINE LAYER DEEPENING TO 4000 FEET...AND INLAND TEMPERATURES 5 DEGREES BELOW NORMAL DURING THE PERIOD. && .AVIATION... 151530Z...THE MARINE LAYER WAS ABOUT 1500 FEET DEEP THIS MORNING WITH CEILINGS AT THE COASTAL AIRPORTS AROUND 1000 FEET ASL. SAN AND CRQ WILL SCATTER OUT BY 17Z AND THE COASTAL BASIN WILL CONTAIN SOME HAZE WITH VIS AROUND 6SM UNTIL CLOSE TO NOON. ISOLATED THUNDERSTORMS ARE EXPECTED TODAY MAINLY OVER THE MOUNTAINS AND DESERTS IN THE AFTERNOON AND EVENING. THE COASTAL CLOUDS WILL SHROUD COASTAL AIRPORTS AGAIN OVERNIGHT AND WILL BE LESS DISRUPTED THAN ON PREVIOUS NIGHTS. EXPECT CEILINGS AT THE COASTAL AIRPORTS SOMETIME BETWEEN 06-10Z AND 16-18Z SAT MORNING. MM && .FIRE WEATHER... WET THUNDERSTORMS TODAY. ISOLATED DRY LIGHTNING POSSIBLE OVER DESERT SLOPES OF SAN BERNARDINO AND SAN JACINTO MOUNTAINS SATURDAY AND POSSIBLE SUNDAY. STRONG DRYING TREND AND INCREASING SOUTHWEST WINDS ALOFT OVER THE WEEKEND COULD LEAD TO CRITICAL FIRE WEATHER PATTERN OVER THE DESERT SLOPES AND HIGH DESERT AREAS BY MONDAY AFTERNOON... WITH WINDS GUSTING NEAR 35 MPH AND RELATIVE HUMIDITY BELOW 10 PERCENT. SIMILAR GUSTY WINDS AND LOW RELATIVE HUMIDITY POSSIBLE EACH AFTERNOON FOR TUESDAY THROUGH THURSDAY. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...FLASH FLOOD WATCH FROM 2 PM THIS AFTERNOON TO 8 PM PDT THIS EVENING FOR APPLE AND LUCERNE VALLEYS-COACHELLA VALLEY-SAN DIEGO COUNTY DESERTS. PZ...NONE. && $$ PUBLIC...BALFOUR AVIATION/MARINE...MM NWS ON THE WEB AT WEATHER.GOV/SANDIEGO ca AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 300 PM MDT FRI AUG 15 2008 .SHORT TERM... (TODAY AND TONIGHT) ANOMALOUS PATTERN IN PLACE WITH CLOSED UPPER LOW OVER WYOMING DROPPING SLOWLY SOUTH INTO COLORADO ON SATURDAY. THIS PUTS SOUTHEAST CO UNDER THE WARM SECTOR OF THE STORM WITH FAIRLY STRONG WARM AIR OVERRIDING COOL SFC AIR IN PLACE ACROSS THE SE PLAINS. MEANWHILE...STRONG UPPER LVL DIFFLUENCE WILL BE POSITIONED OVER THE AREA TONIGHT WITH QG FORCING MORE REMINISCENT OF A WINTER TIME EVENT THAN A LATE SUMMER ONE. SFC FRONTAL BOUNDARY IS CURRENTLY DRAPED THE PANHANDLES DOWN INTO NE NM. EASTERLY LOW LVL FLOW WITHIN THE COOL AIR MASS NORTH OF THE FRONT IS KEEPING FAIRLY HIGH DEW POINTS PINNED UP ACROSS THE SE MTNS/PLAINS WITH READINGS IN THE 50S WITH LOWER 60S ACROSS THE EASTERN BORDER. SO MAIN CONCERN FOR SHORT TERM IS WIDESPREAD SHOWERS AND THUNDERSTORMS WITH POTENTIAL FOR HEAVY RAINFALL. WHERE SUN HAS BROKEN THROUGH CLOUD DECK ON WESTERN FRINGES OVER THE EASTERN MTS/ADJACENT VALLEYS...A FEW SEVERE THUNDERSTORMS HAVE ALREADY DEVELOPED. WITH EASTERLY FLOW BENEATH STRONG NORTHWEST FLOW ALOFT...DEEP LAYER SHEARS ARE MORE THAN SUFFICIENT FOR SUPERCELL THUNDERSTORMS...AND HAVE ALREADY SEEN SOME STRONG ROTATION ON RADAR WITH A THUNDERSTORM OVER CUSTER COUNTY EARLIER. QUESTION IS HOW STABLE LOW LVLS MAY BE ACROSS THE SE PLAINS. NAM AND GFS AND RUC13 INDICATE VERY LITTLE CIN BUT CAPES NOT ALL THAT STRONG EITHER...PROBABLY ONLY AROUND 500-800 J/KG EXCEPT SOME POCKETS OF 1000 J/KG ALONG THE EASTERN MOUNTAINS. LCLS ARE CERTAINLY LOW ENOUGH FOR THE POSSIBILITY OF A TORNADO. THINK MAIN THREAT FOR SEVERE WILL BE ALONG THE EASTERN MOUNTAINS...WITH THUNDERSTORMS WEAKENING SOME AS THEY ENCOUNTER LOWER CAPES AND POSSIBLY SOME CIN ACROSS THE PLAINS. HOWEVER EVEN HERE EXPECT SHOWERS/EMBEDDED TSTORMS TO BECOME MORE WIDESPREAD THROUGH THE EVENING AS OVERRUNNING INTENSIFIES AND UPPER FORCING FROM CLOSED LOW MOVES IN. THIS HEIGHTENS POSSIBILITY FOR FLASH FLOODING ACROSS THE PLAINS WHERE MANY AREAS RECEIVED OVER AN INCH OF RAINFALL FROM THUNDERSTORMS YESTERDAY. THINK ANY FLASH FLOODING MAY STILL BE LOCALIZED...BUT AS SYSTEM EVOLVES INTO A MORE STRATIFORM EVENT...AND SOILS BECOME MORE SATURATED...WE COULD END UP WITH SOME FLOODING INTO SATURDAY AND EVEN SUNDAY AS THE UPPER LOW CONTINUES TO MOVE ACROSS THE AREA AND ROUNDS OF SHOWERS AND EMBEDDED THUNDERSTORMS CONTINUE TO AFFECT THE AREA. GIVEN THE POTENTIAL WENT WITH A FLASH FLOOD WATCH...WHICH MAY NEED TO EVOLVE INTO A FLOOD WATCH AS EVENT GRADUALLY UNFOLDS AND FLOODING MAY RESULT FROM MORE WIDESPREAD STEADY RAINFALL RATHER THAN FROM INTENSE CONVECTIVE CELLS AS TODAY. SATURDAY LOOKS SIMILAR TO TODAY...WITH NOT A LOT OF CAPE...BUT VERY LITTLE CIN EITHER...AND DEEP LAYER SHEARS AROUND 40 KT. BEST PROBABILITY FOR ANY SEVERE THUNDERSTORMS MAY BE ACROSS THE MOUNTAINS AND VALLEYS...WHERE LOW LVL MOISTURE APPEARS TO DEEPEN AND LESS CLOUD COVER EXPECTED. .LONG TERM... (SATURDAY NIGHT THROUGH FRIDAY) THE LARGE UPR LOW WL BE CENTERED OVR CENTRAL CO BY SAT MORNING AND IS THEN FORECAST TO TRACK SEWRD...AND BE CENTERED OVR SERN CO BY SUN EVE...AND THEN CONTINUE ITS SEWRD TRACK INTO NORTH CENTRAL TX BY LATE IN THE DAY MON. WITH VERY MOIST CONDITIONS AND GOOD UPR LIFT CONTINUING SAT NIGHT AND SUN OVR THE SERN PORTION OF THE STATE...WL GO WITH LIKELY POPS. IT SEEMS THAT WITH ALL THE EXPECTED CLOUD COVER AND LAPSE RATES OF 5-6 C/KM...THAT WE WOULD SEE WIDESPREAD RAIN...BUT ONLY ISOLD TSTMS...AND THE RAIN IN MOST AREAS WOULD BE LIGHT TO MODERATE...WITH LOCALLY HEAVY RAIN. WILL CONTINUE THE FLASH FLOOD WATCH INTO SUN EVENING. THEN AS THE LOW MOVES MOVE SE OF THE AREA SUN NIGHT WE LOSE THE GOOD UPR LIFT AND THE BETTER MSTR SHIFTS AWAY FROM THE AREA...SO THE CHANCE FOR PCPN SHOULD DECREASE. SOME WRAP AROUND PCPN WL LIKELY CONTINUE INTO MON OVR THE FAR SERN PLAINS. THE UPR LOW THEN STALLS OVR NORTH CENTRAL TX TUE AND THEN STARTS TO EJECT NEWRD INTO CENTRAL KS WED. SOME PCPN ASSOCIATED WITH THE LOW MAY STILL BE POSSIBLE OVR THE FAR SERN PLAINS ON TUE...WHILE THE REST OF THE AREA WL BE DRIER AND WARMER WITH MAYBE JUST SOME ISOLD TSTMS. A WEAK SHRTWV MOVES OVR THE AREA WED AND WED NIGHT WHICH COULD HELP TO KICK OFF SOME STORMS OVR THE SERN PLAINS AND MTS...AND THEN THU AND FRI LOOK DRIER ACRS THE AREA WITH SW FLOW DEVELOPING IN RESPONSE TO A NEW UPR LOW AND TROF CENTERED OVR WRN MT. && .AVIATION... NUMEROUS SHOWERS AND EMBEDDED THUNDERSTORMS EXPECTED TONIGHT AND SATURDAY ACROSS THE EASTERN HALF OF THE DISTRICT...WITH MVFR TO IFR CIGS EXPECTED THROUGH THE PERIOD. COULD EVEN SEE SOME LOCAL LIFR CIGS DURING THE MORNING HOURS. ROUNDS OF SHOWERS/TSTORMS EXPECTED THROUGH THE PERIOD WITH TIMING OF THESE WAVES ACROSS THE TAF SITES EXTREMELY DIFFICULT. FIRST WAVE WILL LIKELY MOVE ACROSS AREA THIS EVENING...AND ACROSS THE SE CORNER OF THE STATE LATER TONIGHT...THEN EVOLVE INTO A MORE WIDESPREAD STRATIFORM EVENT FOR SATURDAY WITH MVFR TO IFR CIGS REMAINING SOCKED IN ACROSS THE EASTERN MTS/PLAINS THROUGH THE DAY. && .PUB WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH SUNDAY EVENING FOR COZ072>089-093>099. && $$ 31/28 co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 250 AM MDT FRI AUG 15 2008 .SHORT TERM...WATER VAPOR IMAGERY SHOWING STRONG CLOSED LOW NOW MOVING INTO FAR NERN WYOMING AND THIS WILL CONTINUE TO MOVE SOUTHWEST INTO NW CO BY 12 SAT. MODEL TRENDS CONTINUE TO BE CONSISTENT IN THE OVERALL TRACK AND ACCEPTED AS RUC QG HEIGHT TENDENCY HAS BEST FALLS INTO SW WYOMING ATTM. CURRENTLY...PRECIP IS RAPIDLY DEVELOPING ACROSS MUCH OF THE CWA AS MODERATE QG ASCENT MOVING IN AHD OF THE LOW AS NOTED BY RUC LAYERED VERTICAL VELOCITY FIELDS. LOW LEVEL FLOW IS ALSO SHIFTING MORE NORTHERLY AS NEXT SURGE MOVES IN FROM WYOMING. HAVE BOOSTED POPS TO CATEGORICAL THROUGH TODAY WITH THE BEST ASCENT AND UPSLOPE FLOW THRU THE DAY. LOW LVL FLOW SHIFTS MORE SERLY LATER TNT SO RAIN MAY NOT AS WIDESPREAD OVER THE DENVER AREA. STILL DESERVES THE LIKELY POPS AND WILL LET DAY SHIFT DECIDE WETHERE TO BUMP POPS EVEN HIGHER FOR TNT AS QG ASCENT IS STILL FAIRLY HEALTHY. EXPECT EMBEDDED THUNDERSTORMS WITH THE COLDER AIR ALOFT MOVING IN WITH THE LOW BUT DON`T EXPECT SEVERE STORMS WITH LACK OF ANY SIGNIFICANT SFC BASED CAPE WITH VERY COOL LOW LVLS. PERSISTENT LONG TERM RAINFALL OVER THE NEXT SEVERAL DAYS MAY LEAD TO SOME MINOR WATER PROBLEMS...BUT NOT SIGNIFICANT ENOUGH TO ISSUE ANY WATCHES AT THIS TIME. MUCH COOLER TODAY AS 700MB TEMPS DROP TO AROUND +4C. WITH SATURATED AIRMASS HIGHS WILL REMAIN THE MID TO UPPER 50S OVER THE FRONT RANGE. THESE TEMPS WILL VERY WELL LIKELY BUST THE OLD RECORD LOW MAX OF 68 DEGREES WITH NO PROBLEM. AS FOR THE SNOW IN THE MOUNTAINS...SNOW LEVELS WILL REMAIN QUITE HIGH...GENERALLY ABOVE 11000 FEET AND WILL CONTINUE TO MENTION SOME ACCUMLATIONS OVER THE HIGHEST ELEVATIONS. .LONG TERM...MODELS CONTINUE TO DROP A CLOSED UPPER LOW SLOWLY ACROSS COLORADO...AND ARE IN FAIR AGREEMENT THROUGH 60 HOURS. THE NAM HAS BEEN A BIT SLOWED THE MOVEMENT FOR EACH OF THE LAST FEW RUNS. MODELS TYPICALLY DO NOT DO WELL WITH MOVEMENT OF CLOSED LOWS...SO WOULD NOT BE SURPRISED TO SEE US IMPACTED BY THIS LOW THROUGH MONDAY. FOR NOW HAVE LOWERED MAX TEMPS A COUPLE OF DEGREES ON SUNDAY AND MONDAY DUE TO PROXIMITY OF LOW/ AND CLOUDY UPSLOPE CONDITIONS. HIGH POPS IN FORECAST LOOK REASONABLE THROUGH SATURDAY NIGHT...AND THIS COULD BE JUST WHAT IS NEEDED TO RELIEVE OUR DRY CONDITIONS. ALSO RAISED POPS OVER PALMER DIVIDE SUNDAY AND SUNDAY NIGHT AS DOWNWARD FORCING BEHIND LOW SHOULD NOT BE EXPECTED UNTIL AT LEAST MONDAY IF NOT LATER. FORECAST PAST MONDAY UNCHANGED...TIME WILL TELL IF THE UPPER LOW WILL STILL BE IN THE AREA...FOR NOW WE HAVE A MOSTLY DRY AND WARMING TREND IN THE FORECAST BEGINNING MONDAY. && .AVIATION...VARYING IFR/MFVR CONDITIONS EXPECTED AT AREA AIRPORTS DURING NEXT 24 HOURS WITH MOIST...NORTH-NORTHEAST LOW LVL FLOW. HEAVIER SHOWERS AND EMBEDDED TS WILL DROP CIGS TO IFR CONDITIONS AT TIMES. && .BOU WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SWE/RTG co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ALBANY NY 208 AM EDT FRI AUG 15 2008 .SYNOPSIS... AN UPPER AIR LOW...THE SAME ONE THAT PRODUCED RAIN ON MONDAY...WILL APPROACH OUR REGION AGAIN FROM THE EASTERN GREAT LAKES EARLY FRIDAY...AND WORK ACROSS THE REGION THROUGH FRIDAY. THEN...HIGH PRESSURE WILL FINALLY BUILD IN DURING THE WEEKEND. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... JUST WHEN IT LOOKED LIKE THINGS WERE CALMING DOWN...A ROGUE THUNDERSTORM DEVELOPED OVER ULSTER WITHIN THE LAST 30 MINUTES. MSAS ANALYSIS SHOWS A WEAK SURFACE TROUGH CUTTING FROM NORTHEAST PA THROUGH THE LOWER/MID HUDSON VALLEY AND INTO THE BERKSHIRES. LATEST LAPS ANALYSIS SHOWS BEST CAPES IN CWA RIGHT IN THIS AREA...UP TO 1000 J/KG. ALSO RUC ANALYSIS SHOWS BEST SHOWLATERS CENTERED RIGHT OVER ULSTER COUNTY AS WELL ALONG WITH SUPPORTIVE UPPER LEVEL DIVERGENCE. EVENING ALY SOUNDING SHOWED 700 PLUS JOULES/KG ALBEIT WITH FAIRLY WEAK MID LEVEL LAPSE RATES OF 5.75C/KM. TRENDS ON THE RUC THROUGH THE NIGHT ARE FOR INCREASING STABILITY PER INCREASING SHOWLATERS...AND DECREASING UPPER LEVEL DIVERGENCE. WITH THESE FACTORS IN MIND...WILL ALLOW FOR CONTINUED CONVECTIVE ACTIVITY /CALLING IT ISOLD SHRA-TSRA/ IN THIS ZONE THROUGH ABOUT MIDNIGHT OR SO. THEN JUST LIMIT TO SLIGHT CHANCES FOR REMAINDER OF THE OVERNIGHT HOURS. EXPECT CLOUD COVER TO BE FAIRLY PERSISTENT ACROSS SOUTHERN CWA...SO HAVE INCREASED MINS THERE. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/... THIS INCOMING UPPER LOW FEATURE IS THE SAME SYSTEM THAT BROUGHT OUR HEAVY RAINS ON MONDAY. AND YES..MORE RAIN IS LIKELY COME FRIDAY AFTERNOON. AS THE UPPER AIR LOW APPROACHES...BOTH POSITIVE VORTICITY AND WARM ADVECTION WILL INCREASE...PRODUCING LARGE SCALE ASCENT. AS USUAL...THE BIG QUESTION REGARDING CONVECTION AND HOW SEVERE IT WILL GET...WILL DEPEND ON HOW MUCH SUNSHINE (IF ANY) WE WILL RECEIVE ON FRIDAY. WITH THE LARGE SCALE ASCENT...AND PLENTY OF MOISTURE BEING LIFTED ISENTROPICALLY...WE BELIEVE CLOUDS WILL PREDOMINATE WHICH WOULD TEND TO KEEP MLCAPES AOB 1000 J/KG. HOWEVER...CANNOT RULE SOME EARLY SUNSHINE...ESPECIALLY NORTH. FOR NOW...EVEN WITH CLOUDS...THERE APPEARS TO BE ENOUGH INSTABILITY TO WARRANT CONTINUING TO PLACE THUNDER IN THE GRIDS...MAINLY FOR THE AFTERNOON. HOWEVER...NOT COMPELLED TO PLACE ENHANCE WORDING YET. THERE WILL BE SOME FAVORABLE MID LEVEL WIND SHEAR...LESS SO IN THE LOWER LEVELS. OF SLIGHTLY MORE CONCERN IS THE POTENTIAL FOR FLOODING FOR LATE FRIDAY. MORE ON THIS FOLLOWS IN OUR HYDRO DISCUSSION. THE EUROPEAN MODEL CONTINUES TO MOVE THE UPPER LEVEL TROUGH OUT FASTEST TO THE EAST...FIRST THING BY SATURDAY. THE NAM IS THE SLOWEST TO LIFT IT OUT...WITH THE GFS STILL IN BETWEEN AND THE MODEL OF CHOICE. THE EUROPEAN/GFS OPEN THE WAVE UP BY SATURDAY WHILE THE NAM DOES NOT. AGAIN...FOLLOW THE SOMEWHAT MORE PROGRESSIVE GFS SOLUTION. THIS MEANS CONTINUE LIKELY POPS INTO THE FIRST HALF OF FRIDAY NIGHT BUT LOWERING THEM A BIT FOR SATURDAY. WENT WITH ONLY SLIGHT CHANCE IN VALLEY LOCATIONS (FOR THE POSSIBILITY OF A ROGUE SHOWER/THUNDER) BUT 30 POPS OVER THE SLIGHTLY MORE FAVORABLE UPSLOPE HIGHER TERRAIN AREAS. && .LONG TERM /SUNDAY THROUGH THURSDAY/... STARTED WITH MOS GUIDANCE AGAIN TODAY. UPPER LEVEL LOW FINALLY GONE BY START OF PERIOD. THIS MEANS A RELATIVELY DRY SATURDAY AND VERY DRY SUNDAY. HOWEVER...GFS PLACES A SMALL SHORT-LIVED UPPER-LEVEL WAVE OVER THE MID-ATLANTIC REGION ON MONDAY. WITH THE PASSAGE OF A COLD FRONT...TOO...POP CHCS INCREASE TO SLGT ON MON...WITH CHC FAR N ADIRONDACKS. TUE AND WED ARE RAIN-FREE WITH A DOME OF HIGH PRESSURE FROM CENTRAL CANADA IN PLACE...PROVIDING SEASONABLE AND DRY AIR. SLGT CHC SHOWERS RETURN S ON THU AS HIGH STARTS MOVING OFF THE MID- ATLANTIC COAST. MEX GFS DOESN`T APPEAR TO RECOGNIZE MONDAY`S COLD FRONT...WITH MOS GUIDANCE KNOCKING BACK BOTH THE HIGH AND LOW TEMPS SEVERAL DEGREES FROM MEX DAYS 5-8. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... GENERALLY CLEAR SKIES TO START THE PERIOD...ALTHOUGH HIGH AND MID LEVEL CLOUDS WILL BE ENCROACHING FROM THE SOUTH AND WEST THROUGH THE REST OF THE NIGHT AS AN UPPER LEVEL LOW APPROACHES. DESPITE CLEAR SKIES...MAINLY VFR CONDITIONS OCCURRING AS OF 06Z AS A NORTHERLY BREEZE AT KGFL HAS IMPROVED VSBY...BUT FOG HAS SUDDENLY DEVELOPED AT KALB WITH CALM WINDS. AT KGFL WINDS WILL LIKELY BECOME CALM AGAIN AT SOME POINT...WHICH SHOULD LEAD TO ADDITIONAL FOG FORMATION AND ASSOC IFR VSBY. DECIDED TO LEAVE PREDOMINANT VSBY IN MVFR RANGE AND INCLUDE TEMPO FOR IFR VSBY BETWEEN 08Z-12Z. DUE TO CURRENT OBSERVATION OF FOG AT KALB...WILL MENTION TEMPO FOR IFR CONTINUING THROUGH 10Z...ALTHOUGH IT IS NOT TYPICAL FOR FOG TO FORM FIRST AT KALB BEFORE SURROUNDING AREAS...SO WILL MONITOR HOW SITUATION EVOLVES. ELSEWHERE AT KPOU...FOG FORMATION IS NOT ANTICIPATED ESPECIALLY DUE TO INCREASING CLOUDS...ALTHOUGH THERE COULD BE SOME OCCASIONAL MVFR VSBY DUE TO BR. AFTER 12Z FRI MID LEVEL CLOUDS WILL BE THICKENING AS THE UPPER LOW PUSHES EASTWARD ACROSS WESTERN/CENTRAL NY. THE THREAT FOR SHOWERS WILL INCREASE BETWEEN 16Z-18Z...SO WILL MENTION VCSH. THERE IS A CHANCE OF THUNDER DUE TO ELEVATED INSTABILITY...BUT SCATTERED NATURE PRECLUDES MENTION OF ANYTHING OTHER THAN CB APPENDED TO CLOUD GROUP. SHOWERS WILL TEND TO DIMINISH AROUND 01Z-02Z SAT WITH LOSS OF HEATING. WINDS WILL BE VARIABLE AND LESS THAN 5 KTS THROUGH THE NEXT 24 HOURS. OUTLOOK... FRI NGT-SAT...MAINLY VFR. MVFR/IFR NIGHT/EARLY A.M. FOG POSSIBLE. ISOLD/SCT -SHRA/-TSRA. SAT NGT-SUN...VFR...NO SIG WX EXCEPT MVFR/IFR FOG POSSIBLE KGFL. MON...MAINLY VFR...CHC PM -SHRA/-TSRA. TUE...VFR...NO SIG WX. && .FIRE WEATHER... WIDELY SCATTERED SHOWERS AND POSSIBLY A ROGUE THUNDERSTORM THROUGH THE EARLY EVENING. THEN MAINLY QUIET WEATHER UNTIL MORE WIDESPREAD SHOWERS AND THUNDER ARRIVES BY FRIDAY AFTERNOON. DECIDED TO CALL IT A "WET FLAG" ON FRIDAY IN OUR NFDRS FORECAST...AS THE AVERAGE QPF SHOULD EXCEED A QUARTER OF AN INCH ON FRIDAY...WITH LOTS OF CLOUDS TO INHIBIT ANY QUICK DRYING. FINALLY...SOME DRIER WEATHER ON THE WAY FOR THE WEEKEND AND BEYOND. WHILE WE STILL CANNOT ENTIRELY RULE OUT A SHOWER OR STORM SATURDAY...LOOKS MAINLY DRY. NO SHOWERS MENTIONED FOR SUNDAY. RH VALUES WILL APPROACH 100 PERCENT TONIGHT...DROP ONLY TO 60-70 PERCENT FRIDAY AFTERNOON (AT BEST)...BACK UP NEAR 100 FRIDAY NIGHT. BY SATURDAY AFTERNOON...LOWER RH READINGS IN THE 50S ARE ANTICIPATED. THE WIND WILL RELATIVELY LIGHT THROUGHOUT...SOUTHERLY UP TO 10 MPH TOMORROW...TURNING NORTHWEST AT SIMILAR SPEEDS COME SATURDAY. && .HYDROLOGY... NO FLOOD WATCHES AT THIS TIME. NO MODEL SUPPORTS ANY HEAVY QPF...AND EVEN THE ONCE WETTER GFS HAS BACKED OFF ITS HIGH QPF. MOST MODELS INDICATE THE HEAVIEST RAINFALL WILL BE TO OUR EAST COME FRIDAY INTO FRIDAY NIGHT. THAT`S NOT TO SAY WE ARE TOTALLY OUT OF THE WOODS FOR THE POTENTIAL FOR ANY FLOODING. IN THESE SITUATIONS...ANY SLOW MOVING OR BACKBUILDING THUNDERSTORMS COULD PRODUCE LOCALIZED PONDING OF WATER. OUR AVERAGE RIVER BASIN FORECAST IS FOR HALF TO AN INCH OF RAINFALL...WHICH WOULD PRODUCE LITTLE IF ANY SIGNIFICANT RISES IN MAIN WATERSHEDS. THE THREAT OF ANY FLOODING IS LESS THAN 30 PERCENT. WE WILL MENTION HEAVY RAINFALL POSSIBILITIES IN OUR HWO. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...HWJIV NEAR TERM...OKEEFE SHORT TERM...HWJIV LONG TERM...HELLER AVIATION...JPV FIRE WEATHER...HWJIV HYDROLOGY...HWJIV ct AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 330 PM EDT FRI 15 2008 .SYNOPSIS... 18Z WATER VAPOR AND H4 RUC ANALYSIS CONTINUE TO SHOW A LARGE AND UNSEASONABLE ELONGATED LONGWAVE TROUGH COVERING ALL BUT THE FAR WESTERN PORTION OF THE CONTINENT. TWO MAIN PIECES OF ENERGY EMBEDDED WITHIN THE FLOW OF THIS TROUGH INCLUDE A CLOSED OFF UPPER LOW SLIDING SOUTH THROUGH THE INTER-MOUNTAIN WEST...AND ANOTHER CLOSED LOW SPINNING ACROSS THE EASTERN GREAT LAKES. LOCAL AREA RESIDES ON THE FAR SOUTHERN PERIPHERY OF THIS LONGWAVE TROUGH WITH THE OVERHEAD FLOW REMAINING MORE ZONAL THROUGH THE EVENING HOURS BEFORE ADDITIONAL ENERGY APPROACHES FROM THE NORTHWEST. AT THE SURFACE...WEAK TROUGH CONTINUES TO HOLD POSITION WEST TO EAST ACROSS THE AREA FROM OFF THE SOUTHEAST COAST WITH THE SUBTROPICAL RIDGE SUPPRESSED TO THE SOUTH OF THE COASTAL WATERS. BEST FOCUS FOR LOW LEVEL CONVERGENCE REMAINS JUST TO THE SOUTH OF THE BOUNDARY... OVER AND TO THE SOUTH OF THE COASTAL WATERS. CONTINUE TO SEE SCT-NMRS SHOWERS/STORMS THROUGH THIS REGION MOVING WEST TO EAST INTO THE NORTH-CENTRAL FL PENINSULA. PARTLY CLOUDY SKIES THE RULE OVER LAND WITH CU FIELD TAKING SHAPE. FEW SHOWERS AND STORMS STILL EXPECT INTO THE EVENING HOURS...BUT COVERAGE SHOULD CONTINUE MUCH LESS THAN PREVIOUS DAYS. TEMPERATURES AREA-WIDE CURRENTLY IN THE MIDDLE 80S TO LOWER 90S. && .SHORT TERM (TONIGHT THROUGH SUNDAY)... MID/UPPER LEVEL FLOW OVERHEAD BECOME MORE AMPLIFIED OVERNIGHT INTO SATURDAY AS MID-LEVEL ENERGY DIVES SOUTH THROUGH THE UPPER/MIDDLE MS VALLEY INTO THE SOUTHEASTERN STATES. SHOULD SEE ANY SCT SHOWERS/STORMS OVER THE LANDMASS DIMINISH RAPIDLY AFTER SUNSET WITH THE LOSS OF DIURNAL HEATING. HOWEVER...THE COMBINATION OF LAND BREEZE CONVERGENCE AND INCREASING LARGE SCALE LIFT FROM THE APPROACHING SHORTWAVE WILL ALLOW THE CONVECTION ACROSS THE COASTAL WATERS TO GET ITS ACT TOGETHER ONCE AGAIN (ESPECIALLY LATE). AS ALWAYS THERE IS THE CHANCE THAT THIS CONVECTION COULD EFFECT PORTIONS OF SOUTHERN GULF/FRANKLIN COUNTIES AND OVER INTO THE SOUTHEASTERN BIG BEND AS THE OVERALL FLOW PUSHES THE CONVECTION FROM WEST TO EAST. FORECAST DURING THE DAY ON SATURDAY THROUGH THE REMAINDER OF THE WEEKEND BECOMES OF LOWER CONFIDENCE THAN USUAL AS NUMERICAL GUIDANCE CONTINUES TO HAVE DIFFICULT WITH THE ABNORMAL PATTERN AND IS FLIP-FLOPPING BETWEEN SEVERAL DIFFERENT SOLUTIONS. MID-LEVEL ENERGY MOVING INTO THE LOWER MS VALLEY/SOUTHEAST DURING THE DAY WILL RESULT IN A WAVE OF LOW PRESSURE DEVELOPING ALONG THE OLD FRONTAL BOUNDARY OVER THE GULF COAST. MODELS ARE HANDLING THE STRENGTH AND POSITION OF THIS LOW DIFFERENTLY AND RESULTING IN A VARIETY OF LIFT/PRECIP PATTERNS. THE DEVELOPING FRONTAL WAVE WILL GENERATE WARM FRONTOGENESIS TO OUR WEST DURING THE SECOND HALF OF TONIGHT/SAT MORN WITH DECENT LOW LEVEL ISENTROPIC LIFT ALONG THE 300-305K SURFACES. THIS LIFT WILL SLIDE EAST THROUGH THE DAY INTO OUR WESTERN ZONES. GFS IS USUALLY FAIRLY GOOD ABOUT THE POSITION AND STRENGTH OF THESE FRONTAL WAVES AND WILL FOLLOW ITS OVERALL SYNOPTIC PATTERN. HOWEVER...AFTER COORD WITH HPC WILL DUMB DOWN THE MAV POPS AND THE HEAVY RAIN POTENTIAL A BIT AND BLEND POPS/QPF WITH THE SREF ENSEMBLES. EVEN STILL...THIS BLEND IS A SIGNIFICANT INCREASE IN POPS FOR THE DAYLIGHT HOURS TOMORROW. LATEST GRIDS SHOWING 55-65% LIKELY POPS WEST AND 45 TO 55% CHANCE POPS FURTHER EAST. WITH THE HIGHER RAIN CHANCES AND CLOUD COVER WILL ALSO DROP HIGH TEMPS DOWN INTO THE MIDDLE AND UPPER 80S. HIGHEST AFTERNOON TEMPS WILL BE ACROSS THE FAR EAST AWAY FROM THE BEST FRONTAL LIFT. SATURDAY NIGHT/SUNDAY FINDS THE UPPER LEVEL TROUGH STILL ACROSS THE SOUTHEAST WITH PERIODIC PIECES OF ENERGY ROUNDING THE BASE TO AID IN LARGE-SCALE LIFT. THE SURFACE FRONTAL WAVE ALSO MOVES OVERHEAD AND THEN REMAINS IN PLACE THROUGH THE WEEKEND. USING A GFS SOLUTION WOULD YIELD HIGHEST POPS IN THE SOUTH AND EAST IN CLOSER PROXIMITY TO THE DEEP MOISTURE. CURRENT POPS ARE WELL BELOW THE MAV GUIDANCE...BUT ARE A LARGE JUMP FROM THE PREVIOUS FORECAST. IN RESPECT FOR THE FLIP-FLOPPING NATURE OF THE GUIDANCE OVER THE PAST 24 HOURS WILL NOT MAKE ANY LARGER OF A JUMP IN CASE FUTURE RUNS HEAD BACK TOWARD A DRIER SOLUTION. && .MARINE... FORECAST WATERS REMAIN BETWEEN WEAK SURFACE TROUGH TO THE NORTH AND THE SUBTROPICAL RIDGE TO THE SOUTH. WAVE OF LOW PRESSURE IS FORECAST TO DEVELOP ALONG THE SURFACE TROUGH TONIGHT AND TRACK EAST TO THE NORTH OF THE WATER INTO SUNDAY. WITH THE APPROACH OF THIS LOW THE GRADIENT WILL TIGHTENING AND MAY SEE WINDS AND SEAS NEARING CAUTIONARY LEVELS THIS UPCOMING WEEKEND. TROUGH THEN SETTLES SOUTH OVER THE WATERS LATER SUNDAY INTO MONDAY WITH WIND AND SEAS SUBSIDING. KEEPING AN EYE ON THE TROPICS FOR THE EARLY PART OF NEXT WEEK WITH THE POTENTIAL FOR A TROPICAL DISTURBANCE TO APPROACH THE SOUTHEAST UNITED STATES. SEE THE LATEST INFORMATION FROM THE NATIONAL HURRICANE CENTER FOR FURTHER DETAILS. && .AVIATION... VFR CONDITIONS WILL PREVAIL AT AREA TERMINALS FOR THE BALANCE OF TODAY. CONVECTIVE COVERAGE WILL BE ISOLATED ENOUGH TODAY TO ONLY MERIT CB CLOUD GROUPS. OVERNIGHT...MVFR VSBY WILL PREVAIL FOR A FEW HOURS AT ABY AND VLD...STARTING BETWEEN 06-09Z. FOR SAT... THERE IS A LOT OF UNCERTAINTY AS TO HOW EARLY CONVECTION WILL GET STARTED. FOR NOW, CHANCES ARE GREAT ENOUGH TO INCLUDE A MORNING PROB30 GROUP AT PFN AND DHN. && .FIRE WEATHER... RED FLAG CONDITIONS ARE NO LONGER EVEN A REMOTE POSSIBILITY FOR SAT AND SUN. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 71 88 72 88 71 / 20 60 50 50 30 PANAMA CITY 76 86 76 86 74 / 30 60 50 50 20 DOTHAN 70 87 70 87 69 / 20 60 50 40 20 ALBANY 70 89 70 88 69 / 20 50 50 40 20 VALDOSTA 69 90 70 88 70 / 20 50 50 50 30 CROSS CITY 71 89 72 87 71 / 30 60 40 50 30 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...NONE. GM...NONE. && $$ SYNOPSIS/SHORT TERM/MARINE...MROCZKA AVIATION/FIRE WX...WOOL fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 945 AM EDT FRI 15 2008 .SYNOPSIS... 13Z WATER VAPOR AND H4 RUC ANALYSIS CONTINUE TO SHOW A LARGE AND UNSEASONABLE ELONGATED LONGWAVE TROUGH COVERING ALL BUT THE FAR WESTERN PORTION OF THE CONTINENT. TWO MAIN PIECES OF ENERGY EMBEDDED WITHIN THE FLOW OF THIS TROUGH INCLUDE A CLOSED OFF UPPER LOW SLIDING SOUTH THROUGH THE INTER-MOUNTAIN WEST...AND ANOTHER CLOSED LOW SPINNING ACROSS THE EASTERN GREAT LAKES. LOCAL AREA RESIDES ON THE FAR SOUTHERN PERIPHERY OF THIS LONGWAVE TROUGH WITH THE OVERHEAD FLOW CURRENTLY TAKING ON A MORE ZONAL APPEARANCE BETWEEN SHORTWAVES. AT THE SURFACE...WEAK TROUGH CONTINUES TO HOLD POSITION WEST TO EAST ACROSS THE AREA FROM OFF THE SOUTHEAST COAST. THE EXACT POSITION OF THE TROUGH AXIS IS UP FOR DEBATE BUT IS LAYING SOMEWHERE ALONG OR JUST NORTH OF THE GULF COAST. BEST FOCUS FOR LOW LEVEL CONVERGENCE REMAINS JUST TO THE SOUTH OF THIS BOUNDARY (SHOWN BY LATEST RUC ANALYSIS) OVER THE COASTAL WATERS. THIS IS NOT MUCH DIFFERENT A SETUP AS TO WHAT WAS SEEN ON THURSDAY AND ONCE AGAIN IS RESULTING IN A BAND OF SCT-NMRS SHOWERS AND THUNDERSTORMS OVER THE COASTAL WATERS INTO THE NORTH-CENTRAL FLORIDA PENINSULA. THE MAIN THRUST OF THE CONVECTION THIS MORNING HAS BEEN INTO THE COASTLINE SOUTH OF DIXIE COUNTY AND TO THE NORTH OF TAMPA. PARTLY SUNNY SKIES TO START OUT THE MORNING OVER A LARGE PORTION OF THE AREA WITH TEMPERATURES WARMING INTO THE 80S. && .DISCUSSION... MAIN CONVERGENCE BAND IS EXPECTED TO REMAIN OVER THE COASTAL WATERS TO OUR SOUTH THROUGH THE REMAINDER OF THE DAY. OVERALL SHOWER AND THUNDERSTORMS COVERAGE ACROSS LAND AREAS DOES LOOK TO BE LESS THAN PREVIOUS DAYS. HOWEVER...WITH THE SURFACE BOUNDARY IN THE AREA A COMPLETELY DRY DAY IS UNLIKELY AND SHOULD SEE ENOUGH FOCUS FOR WIDELY SCT TO SCT SHOWERS/STORMS DURING THE MIDDLE AND LATER AFTERNOON HOURS. THE LIGHT NW FLOW IN THE 1000-700MB LAYER WOULD SUGGEST THAT THE BEST COVERAGE OF THESE SHOWERS WOULD BE ACROSS GULF/FRANKLIN/WAKULLA/LIBERTY COUNTIES WHERE CONVERGENCE IS MAXIMIZED ALONG INLAND PROPAGATING SEA-BREEZES. OTHER AREAS MORE LIKELY TO SEE SHOWERS WOULD BE ACROSS THE SOUTHEASTERN BIG BEND AS OCCASIONAL ELEMENTS FROM THE MAIN CONVERGENCE BAND OVER THE WATER RIDE NORTH AND INTERSECT THE COASTLINE. OTHERWISE...LOOK FOR A PARTLY SUNNY DAY WITH HIGH TEMPERATURES GENERALLY IN THE LOWER 90S. MID-LEVEL ENERGY DIVING SOUTH THROUGH THE UPPER/MIDDLE MS VALLEY THIS EVENING WILL BEGIN TO AMPLIFY THE FLOW INTO THE SOUTHEASTERN STATES INTO SATURDAY. SHOULD SEE MOST CONVECTION OVER THE LANDMASS DIMINISH RAPIDLY AFTER SUNSET WITH THE LOSS OF DIURNAL HEATING. HOWEVER...THE COMBINATION OF LAND BREEZE CONVERGENCE AND INCREASING LARGE SCALE LIFT FROM THE APPROACHING SHORTWAVE WILL ALLOW THE CONVECTION ACROSS THE COASTAL WATERS TO GET ITS ACT TOGETHER ONCE AGAIN (ESPECIALLY LATE). AS ALWAYS THERE IS THE CHANCE THAT THIS CONVECTION COULD EFFECT PORTIONS OF SOUTHERN GULF/FRANKLIN COUNTIES AND OVER INTO THE SOUTHEASTERN BIG BEND AS THE OVERALL FLOW PUSHES THE CONVECTION FROM WEST TO EAST. && .MARINE... OVERALL FLOW HAS COME DOWN A BIT THIS MORNING FOR THE COASTAL LEGS BUT WILL CONTINUE TO BE HIGHLY INFLUENCE BY SCT-NMRS SHOWERS AND THUNDERSTORMS. WINDS WILL BE LOCALLY GUSTY IN THE VICINITY OF THESE STORMS. SEAS CURRENTLY IN THE 2 TO 4 FOOT RANGE EXPECTED TO SUBSIDE DOWN TOWARD AROUND 2 FEET THIS EVENING. WESTERLY TO SOUTHWESTERLY FLOW WILL CONTINUE THROUGH TONIGHT WITH SHOWERS AND STORMS BECOMING NMRS TO WIDESPREAD DURING THE LATE NIGHT HOURS INTO SATURDAY MORNING. && .AVIATION... ONCE THE MVFR HAZE LIFTS FROM ABY...VFR CONDITIONS WILL PREVAIL AT AREA TERMINALS FOR THE BALANCE OF TODAY. CONVECTIVE COVERAGE WILL BE ISOLATED ENOUGH TODAY TO ONLY MERIT CB CLOUD GROUPS. ONE EXCEPTION IS PFN WHERE A PROB30 GROUP WAS INCLUDED FOR LATE AFTERNOON TS. OVERNIGHT...A BRIEF PERIOD OF MVFR VSBY IS FORECAST FOR ABY AND VLD. && .PREV DISCUSSION... 347 AM EDT FRI AUG 15 2008 .SHORT TERM (TODAY THROUGH SUNDAY)...UNSEASONABLY DEEP TROUGH WILL CONTINUE TO CONTROL THE WEATHER ACROSS THE DEEP SOUTH THROUGH THE WEEKEND. FOR TODAY...SFC TROUGH WHICH PRODUCED THE HEAVY RAINS OF THE PAST FEW DAYS HAS SHIFTED SOUTH OF THE AREA. THIS WILL KEEP THE FORECAST AREA DRIER AND MORE STABLE FOR TODAY WITH WESTERLY LOW LEVEL FLOW. STILL EXPECT SOME SCATTERED SHOWERS THIS AFTERNOON...ESPECIALLY OVER THE FLORIDA ZONES...BUT COVERAGE WILL BE GREATLY DIMINISHED. BY SATURDAY...THE GFS BRINGS YET ANOTHER SHORTWAVE INTO THE BASE OF THE TROUGH. THIS SHOULD PROVIDE SOME ADDITIONAL LIFT AND CONVERGENCE ALONG A WEAK SFC TROUGH. POPS SHOULD BE HIGHER ON SATURDAY. HOWEVER...AMOUNT OF MOISTURE AVAILABLE IS A BIT UNCERTAIN AND WILL KEEP POPS IN THE 30 TO 40 PERCENT RANGE. THE AFOREMENTIONED SHORTWAVE MOVES EAST OF THE AREA BY SUNDAY WITH DRIER NORTHERLY FLOW SETTLING IN ACROSS THE REGION. THIS WILL KEEP MOST AREAS DRY WITH ONLY SLIGHT CHANCE POPS CLOSE TO THE COAST. WITH SLIGHTLY DRIER AIRMASS IN PLACE FOR NEXT FEW DAYS...AFTERNOON TEMPS MAY RISE JUST ABOVE CLIMO INTO THE LOWER TO MID 90S. .LONG TERM (MONDAY THROUGH FRIDAY)...ECMWF AND GFS ENSEMBLES CONTINUE TO FORECAST A DECREASE IN THE AMPLITUDE OF THE UPPER LEVEL TROUGH OVER THE EASTERN U.S. NEXT WEEK...WITH AN INCREASE IN DEEP LAYER RIDGING ACCOMPANIED BY SOME DRYING THROUGH AT LEAST THE MIDDLE OF THE WEEK. THIS WOULD IMPLY BELOW NORMAL POPS AND ABOVE NORMAL MAX TEMPERATURES. THE WILD CARD IN THE FORECAST IS THE ULTIMATE DEVELOPMENT AND TRACK OF THE TROPICAL DISTURBANCE CURRENTLY MOVING WESTWARD OVER THE VIRGIN ISLANDS TOWARD PUERTO RICO. THERE HAS BEEN SOME CONVERGENCE OF SOLUTIONS BETWEEN THE ECMWF AND GFS...BUILDING A STRONG RIDGE TO THE NORTH OF THE FORECAST STORM TRACK ACROSS NEW ENGLAND AND THE NORTHWEST ATLANTIC TOWARD THE END OF THE WEEK...EFFECTIVELY BLOCKING NORTHWARD MOVEMENT OF THE TROPICAL SYSTEM. A TROPICAL STORM TRACKING NORTHWARD TO THE EAST OF FLORIDA WOULD IMPLY GENERALLY DRIER AND WARMER CONDITIONS OVER THE AREA THROUGH THE END OF NEXT WEEK. HOWEVER...THE SAME SYSTEM TRACKING WESTWARD TO THE SOUTH OF OUR AREA WOULD IMPLY MORE MOISTURE AND A GREATER THREAT OF CLOUDS PRECIPITATION...ULTIMATELY DEPENDING ON THE ACTUAL TRACK THE SYSTEM WOULD TAKE. WILL TREND POPS UPWARD AND TEMPERATURES DOWNWARD MORE TOWARD CLIMATOLOGY FOR THE PERIOD THURSDAY THROUGH SATURDAY...RECOGNIZING THE LATTER PART OF THE FORECAST CONTAINS SIGNIFICANTLY GREATER UNCERTAINTY THAN USUAL. && .FIRE WEATHER...IT NOW APPEARS THAT THE DRIEST AIR WILL REMAIN TO THE NORTH OF OUR AREA TODAY...SO WITH LESS DRY AIR PENETRATION SOUTHWARD EXPECT RELATIVE HUMIDITIES TO REMAIN ABOVE CRITICAL LEVELS THIS AFTERNOON. MOISTURE IS EXPECTED TO INCREASE A BIT OVER THE WEEKEND. THEN HIGH PRESSURE AT THE SURFACE AND ALOFT IS EXPECTED TO BUILD OVER THE SOUTHEAST TUESDAY AND WEDNESDAY AS ANOTHER UPPER LEVEL DISTURBANCE PASSES TO THE NORTH...SO FUTURE FORECASTS SHOULD BE MONITORED FOR POSSIBLE AFTERNOON RED FLAG CONDITIONS OVER SOME INLAND PORTIONS OF FLORIDA TUESDAY AND WEDNESDAY. HOWEVER...THE FURTHER INTO NEXT WEEK WE LOOK...THE MORE UNCERTAINTY WE SEE IN THE FORECAST...INCLUDING THE POSSIBILITY OF A TROPICAL STORM SOMEWHERE TO THE EAST OR SOUTH OF OUR AREA BY THE MIDDLE TO END OF NEXT WEEK...SO LONGER RANGE PLANS SHOULD BE MADE ACCORDINGLY. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 93 70 93 70 93 / 30 20 40 20 20 PANAMA CITY 89 76 89 73 90 / 30 20 30 20 20 DOTHAN 94 71 91 69 92 / 20 10 30 10 10 ALBANY 94 68 93 69 93 / 20 10 30 10 10 VALDOSTA 93 69 93 68 92 / 30 10 30 20 10 CROSS CITY 90 71 91 71 92 / 40 30 40 20 20 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...NONE. GM...NONE. && $$ SYNOPSIS/UPDATE/MARINE...MROCZKA AVIATION...WOOL PREVIOUS DISCUSSION...CAMP/DUVAL fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 357 AM EDT FRI AUG 15 2008 .SHORT TERM... TODAY THROUGH SATURDAY NEAR STAGNANT UPPER LOW CENTERED OVER THE EASTERN GREAT LAKES PROVIDED YET ANOTHER FRONTAL PUSH YESTERDAY...ALLOWING SLIGHTLY DRIER AND COOLER AIR TO CONTINUALLY INFILTRATE THE REGION OVERNIGHT. THIS CAN BE OBSERVED BY THE PERSISTENT NE FLOW ANT MANY REPORTING STATIONS ACROSS THE FA. SKIES HAVE MOSTLY CLEARED AS OF 07Z...SAVE A FEW CIRRUS IN THE SOUTH. DEWPOINTS AND TEMPS HAVE FALLEN INTO THE LOW TO MID 50S WITH NO NOTED SIG VSBY RESTRICTIONS. RAINFALL YESTERDAY EVENING HAS PROVIDED SAT NEAR SFC CONDITIONS AT SOME AREAS. HOWEVER...NEAR 20 KNOTS FLOW 1 TO 2 KFT OFF THE SFC PER IWX VWP IS PROVIDING ENOUGH TURBULENT MIXING TO STAVE ANYTHING MORE THAN PATCHY GROUND FG. HAVE DROPPED FOG MENTION TO PATCHY...MAINLY CONFINED TO AREAS THAT RECEIVED PRECIP LAST EVENING. OTHERWISE...UPPER LEVEL PATTERN FEATURES A DRIFTING CLOSED LOW OVER THE WESTERN DAKOTAS WITH NEAR REX BLOCK CONDITIONS ALLOWING FOR SLOW PATTERN EVOLUTION THE NEXT FEW DAYS. LINGERING VORT MAX CENTERED OVER THE EASTERN GREAT LAKES WILL CONTINUE TO AFFECT THE WX IN THE FA AS ANOTHER WEAK VORT LOBE SPINS INTO THE EASTERN MI THIS AFTERNOON. FORECAST MODELS AR NOT OVERLY EXCITED AT PRECIP PROSPECTS IN THE LOCAL FA. THE WRF IS PERHAPS THE MOST AGGRESSIVE...PRODUCING A LARGE SWATH OF QPF ACROSS THE NE THIRD OF THE FA...WHILE THE GFS/UKMET/ECMWF ALL PREFER DRY CONDITIONS. THERE WILL BE WEAK UPPER LEVEL FORCING WITH MAINLY COLD H5 TEMPS TO WORK WITH UNDER AN INCREASINGLY SUBSIDENT ENVIRONMENT. SFC MOISTURE WILL BE LIMITED AND IF THE MAV NUMBERS PAN OUT...THE NE MAY SEE DEWPOINTS DROP INTO THE 40S. THINKING THIS IS A LITTLE TOO DRY GIVEN NE FLOW OFF OF LK HURON AND UPSTREAM OBS FROM YESTERDAY. CONVECTIVE POTENTIAL GIVEN ADVANCING COLD POOL AND A PROLONGED PERIOD OF INSOLATION LOOKS GOOD ENOUGH TO AT LEAST WARRANT SLIGHT CHANCE POPS IN THE NE. THIS IS IN LINE WITH RUC13/SREF/WRF PROGS. THINGS WILL BE HIGHLY DIURNALLY DRIVEN AND ARE EXPECTED TO QUICKLY WAIN BY SUNSET. DRY AIR IN PLACE/LIMITED SOIL MOISTURE/MOSTLY CLEAR SKIES/AND CALM WINDS WILL SUPPORT EXCELLENT RADIATIONAL COOLING FRI NIGHT. EXPECTING WIDESPREAD LOWS AROUND 50 WITH A FEW AREAS IN THE UPPER 40S...NOT YOUR TYPICAL AUGUST READINGS. SFC AND UPPER LEVEL RIDING WILL PROVIDE PARTLY TO MOSTLY SUNNY CONDITIONS SAT. ADDED BL MOISTURE FROM LK MI MAY PROVIDE A MOSTLY TO PT CLOUDY SKY IN THE NW GIVEN PROGGED LK INSTABILITY...BUT THINGS SHOULD MIX OUT BY LATE MORNING. LOOK FOR SLIGHTLY WARMER TEMPS WITH DRY CONDITIONS. NW FLOW WILL CONTINUE TO DOMINATE THE WEATHER SAT NIGHT...AS SEVERAL RIDGE TOPPING IMPULSES WILL SPILL INTO THE UPPER MIDWEST/GREAT LAKES AND COULD PROVIDE ENOUGH LIFT FOR SOME MID LEVEL CLOUD AND MAYBE AN OUTSIDE SHOWER IN THE FAR NORTH...BUT GIVEN UNKNOWN INTENSITY AND TRACK OF THESE FEATURES...A DRY FORECAST IS PRUDENT AT THIS TIME. && .LONG TERM... SUNDAY THROUGH THURSDAY...THE PERSISTENT BLOCKING PATTERN WILL CONTINUE THROUGH THE PERIOD AS AN UPPER LOW CUTS OFF OVER THE HIGH PLAINS OR CENTRAL PLAINS EARLY IN THE PERIOD. THE LATEST GFS AND ECMWF MODEL TRENDS FAVOR THE PREVIOUS FEW RUNS OF KEEPING THE UPPER LOW TO THE WEST WITH AN UPPER RIDGE OVER THE OHIO RIVER VALLEY. THERE IS ALSO WIDESPREAD GFS ENSEMBLE SUPPORT OF THE RIDGE PERSISTING OVER THE FORECAST AREA THROUGH WEDNESDAY...SO WILL MAINTAIN THE ONGOING DRY FORECAST. HOWEVER...SOME CONCERN WITH A SHORTWAVE DROPPING SOUTHEAST IN NW FLOW ON SUNDAY...WITH THE POTENTIAL TO BRING SOME SHOWERS AT LEAST TO NORTHERN AREAS INCLUDING FAR SOUTHERN LOWER MI...FAR NW INDIANA AND NW OH. THE NAM/WRF IS MORE ROBUST WITH THIS FEATURE THEN THE GFS...SO WITH TIMING AND STRENGTH UNCERTAINTIES...KEPT SUNDAY DRY. OTHERWISE...WITH THE UPPER LEVEL RIDGE BUILDING INTO THE AREA...RAISED HIGHS A FEW DEGREES MOST PERIODS AFTER SUNDAY. && .AVIATION.../06Z TAFS/ SFC HIGH PRESSURE CONTINUES TO BUILD INTO THE REGION AS UPPER LEVEL LOW PRESSURE RESIDES OVER THE EASTERN GREAT LAKES. MAIN CONCERN TONIGHT WILL BE BR/FG DEVELOPMENT...ESPECIALLY AT FWA WHERE RAIN OCCURRED LAST EVENING. SOUNDING PROGS INDICATE SUSTAINED NE FLOW JUST OFF THE SFC...WHICH WOULD ACT TO STAVE OFF ANY WIDESPREAD BR/FG DEVELOPMENT PER TURBULENT MIXING OF DRY AIR ALOFT. HOWEVER...DO EXPECT AREAS OF SHALLOW BR/FG TO BE ONGOING BY MID MORNING DUE TO GOOD RADIATIONAL COOLING PER CLEAR SKIES AND RATHER LIGHT SFC WINDS. HAVE WENT WITH 6SM AT FWA...WITH RESTRICTIONS DOWN TO 3SM POSSIBLE. EVEN LOWER VISBYS ARE A POSSIBILITY...BUT GIVEN CONCERNS TURBULENT MIXING POTENTIAL AND ADVANCING CIRRUS...WILL HOLD OFF ON ANYTHING LOWER...RELYING ON CLIMO. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...CHAMBERLAIN LONG TERM...SKIPPER AVIATION...CHAMBERLAIN in AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE NEW ORLEANS LA 849 PM CDT FRI AUG 15 2008 .UPDATE... MINOR UPDATE TO WEATHER AND POPS FOR TONIGHT...AS OVERALL CONVECTIVE COVERAGE HAS DECREASED SUBSTANTIALLY IN THE LAST COUPLE OF HOURS. AFTER LOOKING AT SATELLITE TRENDS AND LATEST RUC ANALYSIS...HAVE LOWERED POPS ABOUT 20 PERCENT ACROSS THE BOARD. KEEP ISOLATED POPS OVER THE COASTAL ZONES...WITH SCATTERED POPS OVER NORTHERN ZONES...CLOSER TO WEAK CONVERGENCE ZONE CURRENTLY OVER CENTRAL MISSISSIPPI. NO OTHER UPDATES TO THE FORECAST WERE MADE. && .PREV DISCUSSION... /ISSUED 332 PM CDT FRI AUG 15 2008/ SYNOPSIS... SURFACE HIGH PRESSURE IS CENTERED OVER THE FLORIDA PENINSULA. THE SURFACE BOUNDARY HAS MOVED NORTHWARD AND IS EVIDENT AS A GENERAL WEAKNESS IN THE RIDGE ACROSS CENTRAL GEORGIA...ALABAMA AND MISSISSIPPI...NORTHERN LOUISIANA AND CENTRAL TEXAS. THUS FAR CONVECTION HAS MAINLY BEEN LIMITED TO AREAS SOUTH OF THE INTERSTATE 10/12 CORRIDOR. CLOUDS HAVE KEPT TEMPERATURES IN THE MID TO UPPER 80S ACROSS THE AREA...THOUGH A FEW MORE DEGREES OF WARMING WILL BE POSSIBLE. SHORT TERM...TONIGHT THROUGH MONDAY... MAIN FORECAST ISSUE WILL BE IN THE FIRST PERIOD. THERE IS SOME CONSIDERABLE MODEL SPREAD CONCERNING PROBABILITY OF PRECIP FOR TONIGHT. THE NAM IS FORECASTING 10 TO 20 PERCENT ACROSS THE BOARD WHILE THE ECM IS COMING IN AROUND 40 PERCENT. THE GFS IS CONSIDERABLY WETTER AT AROUND 60 PERCENT FOR MOST OF THE AREA WITH. WITH A SHORTWAVE TROUGH AXIS FORECAST TO MOVE ACROSS THE REGION TONIGHT...WENT AHEAD AND BUMPED POPS UP INTO THE HIGH END CHANCE CATEGORY. THE LARGE AREA OF QPF GREATER THAN ONE INCH IN THE GFS IS AT LEAST PARTIALLY DUE TO GRID-SCALE FEEDBACK. HPC HAS NOTED THAT BULLSEYES IN THE GFS GENERALLY SIGNAL HEAVY PRECIP POTENTIAL...BUT ARE OFTEN TOO FAR TO THE NORTH. WITH THIS IN MIND...WILL GO AHEAD AND CARRY HEAVIER PRECIP IN THE COASTAL AREAS AND WILL MENTION THE POSSIBILITY OF HEAVY RAIN IN AN UPDATED HAZARDOUS WEATHER OUTLOOK. BEYOND TONIGHT...THE FORECAST HAS NOT CHANGED MUCH. SOUTHERLY FLOW WILL CONTINUE TO PUMP GULF MOISTURE INTO THE AREA WITH SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS SATURDAY THROUGH MONDAY... MAINLY IN THE AFTERNOON. LONG TERM...TUESDAY THROUGH FRIDAY... MODELS CONTINUE TO SHOW LARGE DIFFERENCES BOTH WITH EACH OTHER AND FROM RUN TO RUN. WITH VERY LITTLE CONFIDENCE IN ANY ONE MODEL SOLUTION...HAVE NOT MADE MANY CHANGES TO THE FORECAST SINCE IT WAS ALREADY IN LINE WITH THE MODEL CONSENSUS...WHICH CALLS FOR NEAR NORMAL TEMPERATURES WITH A CHANCE OF SHOWERS AND THUNDERSTORMS EACH AFTERNOON. ONE FEATURE THAT WILL HAVE TO BE WATCHED IS TROPICAL STORM FAY. THE MODELS CANNOT SEEM TO GET A HANDLE ON THE INITIAL POSITION AND MOTION OF FAY...WHICH RESULTS IN LARGE RUN TO RUN DIFFERENCES IN THE FORECAST LOCATION. AT THIS TIME IT DOES NOT LOOK LIKE FAY WILL BE MUCH OF A THREAT TO OUR FORECAST AREA. FOR MORE INFORMATION ON FAY...REFER TO NATIONAL HURRICANE CENTER ADVISORIES AND FORECASTS. AVIATION... CONVECTION MAINLY WAS AFFECTING THE BATON ROUGE THROUGH NEW ORLEANS AREA THIS AFTERNOON. ACTIVITY SHOULD BEGIN TO DIMINISH WITH SUNSET...ALTHOUGH ACTIVITY IS EXPECTED TO BEGIN DEVELOPING/SPREADING INTO THE AREA TOMORROW MORNING. FOR TOMORROW MORNING THE TAFS WILL BE LIMITED TO INDICATING CB THROUGH 18Z. OUTSIDE CONVECTION AND 3-5SM FOG AROUND DAYBREAK...CONDITIONS GENERALLY SHOULD REMAIN VFR AT MSY...BTR...GPT...MCB. MARINE... WINDS GENERALLY LESS THAN 15 KNOTS ARE EXPECTED ACROSS THE AREA THROUGH THE WEEKEND. THE MAIN QUESTION WILL BE WITH THE TRACK OF THE TROPICAL WAVE NEAR THE DOMINICAN REPUBLIC EARLY THIS AFTERNOON. IF IT TRACKS ON THE WEST SIDE OF FLORIDA...WINDS AND SEAS COULD BE HIGHER AROUND THE MIDDLE OF NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... MCB 72 86 71 88 / 30 60 30 30 BTR 74 87 73 89 / 30 60 30 30 MSY 76 88 75 89 / 20 60 30 30 GPT 74 86 73 88 / 20 60 30 30 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...NONE. GM...NONE. MS...NONE. GM...NONE. && $$ la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SHREVEPORT LA 414 PM CDT FRI AUG 15 2008 .DISCUSSION... COMPLICATED FORECAST THROUGH BOTH THE SHORT AND LONG TERM...AS MANY SUBTLE FEATURES WILL COME INTO PLAY AHEAD OF THE CLOSED LOW WHICH CONTINUES TO DROP S ALONG THE ROCKIES THIS WEEKEND. 20Z SFC ANALYSIS IS VERY DIFFICULT TO ANALYZE A FRONTAL BNDRY...GIVEN MULTIPLE OUTFLOWS WHICH HAS ALLOWED WINDS TO BECOME QUITE VRB ACROSS THE REGION. BUT A WEAK COOL FRONTAL BNDRY APPEARS TO STRETCH FROM JUST N OF THE RED RIVER IN SRN OK...INTO WCNTRL AND NRN AR THIS AFTERNOON. MEANWHILE...VISIBLE SATELLITE LOOPS INDICATE A WELL-DEFINED SPIN BETWEEN GYI AND MLC THIS AFTERNOON...LIKELY ASSOCIATED WITH 850MB LOW. WATER VAPOR LOOPS ARE INDICATE LEAD SHORTWAVE NOW TRAVERSING INTO SW AR ATTM...WHICH SHOULD EXIT THE REGION TO THE E AFTER 6Z TONIGHT. THE LATEST RUC/NAM/GFS ALL INDICATE THE 850MB LOW AND ITS ATTENDANT TROUGH AXIS AND SFC FRONTAL BNDRY DRIFTING SE ACROSS EXTREME NE TX AND INTO NRN LA LATER TONIGHT...WITH STRONG ISENTROPIC LIFT INCREASING IN VC OF THE LOW ACROSS EXTREME E TX/NW LA/SW AR LATE...TYPICAL WITH A SUCH A CLOSED CIRCULATION DURING THE OVERNIGHT HRS. THUS...WE MIGHT END UP IN A HIGH POP/LOW QPF EVENT TONIGHT...BUT GIVEN CONSISTENCY AMONGST THE SHORT TERM MODELS...HAVE INCREASED POPS TONIGHT TO HIGH CHANCE JUST ABOUT AREAWIDE...WITH LIKELY POPS CONCENTRATED NEAR THE PATH OF THE 850MB LOW BY 6Z. MOSAIC RADAR ALSO INDICATING A LARGE MASS OF CONVECTION DRIFTING N FROM SE TX/SRN LA...ASSOCIATED WITH A WEAK MID LEVEL SHEAR AXIS. MODELS NOT HANDLING THIS WELL AT ALL...BUT AM THINKING THIS MAY WIND DOWN SOME AFTER SUNSET THIS EVENING...ALTHOUGH REMNANT OUTFLOWS COULD INTERACT WITH THE 850MB LOW AND ALLOW FOR ADDITIONAL REGENERATION ACROSS NCNTRL LA. THE 850MB LOW WILL SLOWLY CREEP E ACROSS N LA SATURDAY MORNING...EXITING THE AREA AFTER 18Z. THUS...RETAINED HIGH CHANCE POPS ACROSS N LA/SCNTRL AR...LIKELIES FOR ERN NCNTRL LA...WITH THE SHRA AND ISOLATED CONVECTION ENDING FROM W TO E. WEAK FRONTAL BNDRY WILL LIKELY SAG SLOWLY S OF I-20 SATURDAY AFTERNOON...BEFORE STALLING ACROSS DEEP E TX/NCNTRL OR CNTRL LA. MUCH LIKE TODAY...MAX TEMPS SATURDAY ARE ANYONE/S GUESS...BUT BELIEVE CLOUD COVER/RAIN WILL INHIBIT MUCH OF A WARMUP...THUS HAVE TRENDED TEMPS AT OR BELOW MAVMOS /IN THE MID/UPPER 80S/. THE 850MB TROUGH WILL LIKELY HANG UP SOMEWHERE S OF I-20 SATURDAY...ALTHOUGH DIRTY NW FLOW WILL PERSIST FOR MUCH OF THE WEEKEND AHEAD OF THE SWD DIGGING CLOSED LOW. ENOUGH LOW LEVEL DRY AIR SHOULD BE ABLE TO BACKDOOR FAR ENOUGH S INTO SE OK/SW AR SUNDAY...THUS HAVE DROPPED POPS FOR THESE AREAS...WITH 850MB TROUGH AND ASSOCIATED STATIONARY FRONTAL BNDRY HANGING TO THE S. THE GFS/ECMWF ARE IN GOOD AGREEMENT WITH THE CLOSED LOW ENTERING THE OK/TX PANHANDLES SUNDAY NIGHT...WITH A SSE RETURN FLOW COMMENCING ACROSS TX. THUS...THE SFC BNDRY WILL SLOWLY BEGIN TO WORK BACK NNW SUNDAY NIGHT...WITH AREAS OF CONVECTION LIKELY DEVELOPING ACROSS CNTRL/S TX AND SPREADING N ACROSS THE STATE. GIVEN POSITIONING UNCERTAINTIES IN RECENT MODEL RUNS...CAN NOT QUITE BITE ON LIKELY POPS YET...BUT HIGH CHANCE POPS WILL REMAIN ACROSS E TX MONDAY...WHICH COULD POSSIBLY SPREAD A TAD E INTO WRN LA/SW AR MONDAY NIGHT/TUESDAY. HAVE AGAIN HIGHLIGHTED HEAVY RAIN POTENTIAL IN THE AFTERNOON HWO...WITH PERSISTENT TRAINING OVER ALREADY SATURATED GROUNDS POSSIBLY LEADING TO AN INCREASED FLASH FLOOD RISK. PROGS STILL INDICATE THIS SYSTEM STAYING PUT THROUGH AT LEAST MID WEEK...AS BROAD UPPER RIDGING EXPANDS ACROSS MUCH OF THE COUNTY. TROUGH MAY BEGIN TO OPEN UP/EJECT NE OUT OF THE SRN PLAINS BY THURSDAY/FRIDAY...BUT HAVE RETAINED LOW CHANCE POPS AREAWIDE SHOULD THIS SYSTEM REMAIN IN PLACE. PRELIMS TO FOLLOW BELOW... 15 && .AVIATION... SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE TO DEVELOP ACROSS THE REGION AND MOVE NORTHEAST. THE CONVECTION MAY DECREASE IN COVERAGE AFTER SUNSET...BUT AT MINIMUM...ISOLATED COVERAGE IS EXPECTED THROUGHOUT THE NIGHT. CIGS AND VSBYS FREQUENTLY MVFR IN AND AROUND THE CONVECTION...WITH LOCALIZED IFR IN THE STRONGER STORMS. IFR CIGS AND VSBYS WILL BECOME MORE WIDESPREAD...ESPECIALLY AFTER 06Z...AS WET GROUND AND STABLE BOUNDARY LAYER RESULT IN FOG FORMATION AND ASSOCIATED LIFR CIGS. CONDITIONS SHOULD IMPROVE SLOWLY AFTER 16/15Z...BUT ADDITIONAL CONVECTION STILL POSSIBLE. /14/ && .PRELIMINARY POINT TEMPS/POPS... SHV 72 86 71 89 71 / 60 50 20 20 20 MLU 72 86 70 90 71 / 50 60 20 20 20 DEQ 69 85 66 88 68 / 50 30 20 10 10 TXK 71 86 69 90 71 / 60 40 20 10 10 ELD 70 86 66 90 69 / 50 50 20 10 10 TYR 70 87 71 88 72 / 30 20 20 20 30 GGG 71 87 70 88 71 / 50 20 20 20 30 LFK 73 90 72 89 72 / 50 40 30 30 40 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 15/14 la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SHREVEPORT LA 1121 AM CDT FRI AUG 15 2008 .DISCUSSION... WATER VAPOR IMAGERY INDICATES LEAD SHORTWAVE TRAVERSING THE RED RIVER VALLEY OVER SRN OK/N TX AHEAD OF CLOSED LOW DIGGING S ACROSS WYOMING ATTM...WITH MOSAIC 88-D IMAGERY INDICATING LARGE AREA OF CONVECTION EXTENDING FROM NEAR SEP...TO CRS...TO TYR...INTO SW/SCNTRL AR. THE RUC INITIALIZED BEST ON THE CURRENT CONVECTION...WITH DRIER AIR BEGINNING TO ADVANCE SE ACROSS SE OK/ADJACENT SW AR...THUS ALLOWING RAIN AREA TO DIMINISH THE LAST CPL HRS. HOWEVER...CONVECTION IS MORE ORGANIZED ALONG THE BASE OF THE TROUGH ALONG I-20 W OF TYR...THUS HAVE CONCENTRATED BEST POPS THROUGH EARLY AFTERNOON FOR THE WRN SECTIONS OF E TX. IN ADDITION...LEAD OUTFLOW BNDRY HAS ADVANCED WELL SE OF THE CONVECTION...AND WAS LOCATED FROM NEAR HEMPHILL...TO RSN...TO E OF ELD AS OF 16Z. BREAKS IN THE CLOUD COVER HAS ALLOWED FOR TEMPS TO WARM IN THE MID 80S ACROSS SE TX/CNTRL LA WHERE OUTFLOW BNDRY HAS YET TO AFFECT THESE AREAS...THUS WITH TIME...BELIEVE MORE WIDELY SCATTERED CONVECTION WILL DEVELOP BY EARLY AFTERNOON. WITH SHORTWAVE EXPECTED TO DROP MORE ESE INTO SW AR BY AFTERNOON...BELIEVE THE CURRENT ORGANIZED CONVECTION MAY DIMINISH SOME AS IT ENTERS DEEP E TX...BUT DIFFERENTIAL HEATING BNDRY SETTING UP AHEAD OF THE COMPLEX WILL LIKELY FUEL THESE STORMS THROUGH LATE AFTERNOON/EARLY EVENING. HAVE RAISED POPS ACROSS DEEP E TX/NW LA...WITH LITTLE CHANGE ELSEWHERE TO POPS. AFTERNOON MAX TEMPS WILL BE A TOUGH CALL...GIVEN THE RAIN/EXTENSIVE CLOUD COVER...BUT HAVE LOWERED TEMPS ACROSS MUCH OF THE AREA...WITH SE OK/E TX/SW AR LIKELY NOT GETTING OUT OF THE 80S. WILL ADDRESS POTENTIAL FOR HEAVY RAINFALL ASSOCIATED WITH THE CLOSED LOW DIVING S INTO THE SRN PLAINS BY MONDAY IN THE AFTERNOON DISCUSSION. ZONES ALREADY OUT...GRIDS WILL BE AVAILABLE SHORTLY. 15 && .AVIATION... SHRA/TSRA WEST AND NORTH OF ELD-TYR LINE WILL CONTINUE TO MOVE EAST THROUGH THE EARLY AFTERNOON. ADDITIONAL CONVECTIVE DEVELOPMENT EXPECTED DURING THE AFTERNOON AND CONTINUING TONIGHT. CIGS AND VSBYS FREQUENTLY MVFR IN AND AROUND THE CONVECTION...WITH LOCALIZED IFR IN THE STRONGER STORMS. IFR CIGS AND VSBYS WILL BECOME MORE WIDESPREAD...ESPECIALLY AFTER 06Z...AS WET GROUND AND STABLE BOUNDARY LAYER RESULT IN FOG FORMATION AND ASSOCIATED LIFR CIGS. CONDITIONS SHOULD IMPROVE SLOWLY AFTER 16/15Z...BUT ADDITIONAL CONVECTION STILL POSSIBLE. /14/ && .PRELIMINARY POINT TEMPS/POPS... SHV 90 72 89 70 90 / 50 40 50 20 40 MLU 93 70 86 68 91 / 30 40 50 20 20 DEQ 86 68 86 66 88 / 60 40 50 30 50 TXK 87 70 88 69 89 / 60 40 50 20 40 ELD 89 70 89 66 90 / 40 40 50 20 20 TYR 87 73 90 71 89 / 70 30 40 40 50 GGG 87 71 89 70 88 / 70 30 50 30 50 LFK 92 72 90 71 90 / 40 20 50 30 50 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 15/14 la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CARIBOU ME 243 PM EDT SAT AUG 16 2008 .SYNOPSIS... A TROUGH OF LOW PRESSURE WILL MOVE ACROSS THE AREA TONIGHT THROUGH SUNDAY MORNING. HIGH PRESSURE WILL MOVE IN LATER SUNDAY INTO SUNDAY NIGHT. A STRONG COLD FRONT WILL APPROACH ON MONDAY AND CROSS THE AREA EARLY TUESDAY. HIGH PRESSURE WILL SETTLE OVER THE REGION BY LATE NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AREA OF SHOWERS AND THUNDERSTORMS DEVELOPED EARLIER TODAY OVER SOUTHERN PORTION OF WASHINGTON COUNTY AND COASTAL WATERS SO ADJUSTED GRIDS TO BETTER THIS EVENT. FOR REMAINDER OF AFTERNOON HAVE USED 1500Z RUC13 TO CREATE INITIAL GRIDS FOR ALL PARAMETERS. HAVE MANUALLY ADJUSTED POP...SKY AND QPF AREA TO BETTER FIT RUC VORTICITY FOR THIS AFTERNOON INTO EARLY EVENING SINCE THERE SEEMS TO BE GOOD CORRELATION BETWEEN THE TWO. FOR LATER TONIGHT HAVE USED MODEL BLEND OF NAM12...GFS40 AND SREF THEN MERGED MODEL BLEND DATA WITH TODAYS RUC13 DATA. EXPECT UPPER LOW PRESSURE TO MOVE TO THE EAST OF THE FORECAST AREA LATER TONIGHT ALONG WITH ACCOMPANYING VORTICITY MAX. PRECIPITATION IS EXPECTED TO END QUICKLY AS UPPER SYSTEM MOVES TO THE EAST OF THE AREA. FOR WIND HAVE USED GMOS. HAVE NOT MADE ANY CHANGES TO TEMPERATURE OR DEW POINT WHICH APPEARS TO BE WORKING WELL. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... MAIN FOCUS WILL BE NEXT FRONTAL BOUNDARY APCHG THE CWA MONDAY AFTERNOON INTO EARLY TUESDAY AFT A BRIEF BREAK ON SUNDAY. DECIDED ON A GFS40/SREF BLEND INTO TUESDAY. ECMWF WAS USED FOR PLACEMENT AS IT HAS BEEN CONSISTENT W/SLOWING THINGS DOWN UNTIL MONDAY AFTERNOON AND HANGING ON THROUGH EARLY TUESDAY UNTIL UPPER TROF SWINGS THROUGH. SO LET/S BEGIN...SFC TROF IS EXPECTED TO MOVE ACROSS THE CWA ON SUNDAY W/SOME WEAK FORCING IN THE MID-LVLS TO ALLOW FOR SOME ISOLD SHOWERS ACROSS THE CWA EARLY ON AND THEN ATMOS LOOKS TO DRY OUT W/SOME DOWNSLOPING WINDS FROM 925-850MBS. MDL SNDGS POINT TO THINGS BEING STABLE W/LITTLE IN THE WAY OF ANY SB/MUCAPE. THEREFORE...OPTED TO KEEP THE MENTION OF THUNDER OF FOR SUNDAY. GMOS TEMPS ACCEPTED W/READINGS IN THE MID/UPPER 70S ACROSS THE N AND AROUND 80 CENTRAL AND DOWNEAST AREAS. FRONTAL BOUNDARY IS EXPECTED TO BEGIN TO MOVE IN FROM THE W ON MONDAY W/LLVL WAA OUT AHEAD OF THE FRONT EARLY ON. SOME INSOLATION THROUGH 18Z ESP S OF CAR-PQI SHOULD ALLOW FOR DESTABILIZATION TO OCCUR. LAPSE RATES ARE PROGGED TO STEEPEN W/700-500 MB LAPSE RATES AROUND 6.5 C/KM. DECENT SHEAR IS NOTED ESP FROM 0-6KM AROUND 30 KTS. SB CAPES THIS FAR OUT SUGGEST 1000-1500 J/KG IN THE AFOREMENTIONED AREAS. DECIDED TO ADD SCT TSTMS FOR MONDAY AFTERNOON INTO MONDAY EVENING. FRONTAL BOUNDARY LOOKS TO SHARPEN AS IT MOVES ACROSS THE CWA MONDAY NIGHT INTO EARLY TUESDAY. TRIED TO SHOW POPS SHIFTING E W/THE FRONT W/VALUES DECG TO THE CHC CATEGORY BY MID MORNING TUESDAY AS MOST OF THE FORCING MOVES INTO NEW BRUNSWICK. ONCE AGAIN USED THE GMOS TEMPERATURES AND ADJUSTED ACCORDINGLY ESP FOR MONDAY MAXES TO PLAY THEM ON THE UPWARD SIDE W/HEATING EARLY. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... GMOS WAS LOADED HERE AND ONCE AGAIN USING THE 00Z ECMWF AS A GUIDE ADJUSTED POPS MAINLY LATER IN THE WEEK TO KNOCK THEM BACK A BIT. OTRW...NO CHGS MADE. MIDNIGHT CREW CAN ADJUST W/THE NEXT RUN. && .AVIATION /17Z SATURDAY THROUGH WEDNESDAY/... NEAR TERM: EXPECT VFR CONDTIONS TONIGHT IN NORTH. FOR KBGR AND KBHB EXPECT IFR CONDTIONS TONIGHT DUE TO CEILING AND VISIBILITY DUE TO BOTH FOG AND SHOWERS. LOOKING FURTHER OUT: VFR MOSTLY RIGHT INTO MONDAY AND THEN CONDITIONS DROP BACK LATER MONDAY THROUGH EARLY TUESDAY TO MVFR/IFR AS FRONTAL BOUNDARY MOVES ACROSS THE REGION. && .MARINE... NEAR TERM: WINDS VERY LIGHT ACROSS THE COASTAL WATERS. HAVE INITIALIZED WIND GRIDS INTO EARLY THIS EVENING THEN MERGED WIND GRIDS WITH NAM12 WINDS LATER TONIGHT. HAVE LOWERED SPEEDS 2 KNOTS TO ADJUST FOR BOUNDARY LAYER. FOR WAVES: SWELL FIELD CONTINUES TO DOMINATE. WNA APPEARS TO HAVE GOOD HANDLE ON LONG PERIOD WAVES SO WILL ONLY MAKE MINOR ADJUSTMENTS TO KEEP WAVE HEIGHTS AROUND 3 FEET AND ALSO ADJUST WAVES IN INTRA-COASTAL ZONE. WILL ADD WIDE SPREAD FOG THIS AFTERNOON THRU 06Z WITH BUOY REPORTS VISIBILITY BELOW 1 NM. SHORTER TERM: NO HEADLINES. STARTED WINDS OUT USING NAM12/GFFS40 AND THEN WENT W/THE GFS40 WINDS W/ADJUSTMENTS DOWNWARD ESP AT NIGHT. WNAWAVE LOOKS TO BE RUNNING HIGH FOR SEAS. DECIDED ON CUTTING THE HEIGHTS BACK ONE FOOT THIS FCST CYCLE. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ NEAR TERM...MIGNONE SHORT TERM...HEWITT LONG TERM...HEWITT/RAHE AVIATION...MIGNONE MARINE...MIGNONE/HEWITT me AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 121 AM EDT FRI AUG 15 2008 UPDATED AVIATION DISCUSSION FOR 06Z TAFS .SYNOPSIS... WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A FAIRLY AMPLIFIED PATTERN OVER NOAM. A BROAD MID-LVL RIDGE WAS OVER SW CANADA AND MUCH OF THE WRN CONUS WHILE A TROF WAS OVER ERN CANADA INTO THE CENTRAL/ERN GREAT LAKES. A CLOSED LOW HAS MOVED FROM SRN SASK INTO NE MT AND WILL HAVE LTL EFFECT ON OUR WX HERE. A SHORTWAVE AND ASSOC COLD POOL MOVING THROUGH THE BASE OF THE TROF HAS TRIGGERED SOME CONVECTION OVER FAR ERN UPR MI AS NOTED ON RADAR. LOOKS LIKE MAY EVEN ALTHOUGH SHORTWAVE IS NOT PRODUCING MUCH IN THE WAY OF CLOUD COVER...RADARS IN ONTARIO DO SHOW A FEW -SHRA. ACROSS UPPER MI...WITH THE EXCEPTION OF SOME CLOUDS OVER THE SW THIRD...SKIES ARE CLEAR. && .SHORT TERM (TONIGHT AND FRIDAY)... SOME LOCALIZED CONVERGENCE ALONG DEVELOPING LAKE BREEZE BOUNDARY MAY EVEN POP UP A SHOWER OVER SRN SCHOOLCRAFT COUNTY LATE THIS AFTERNOON BUT ANY SHOWER WOULD BE SHORT-LIVED AS MODEL SNDGS A SHARP INCREASE IN MID-LVL SUBSIDENCE TOWARD 00Z THIS EVENING IN THE WAKE OF THE SHORTWAVE. MODELS INDICATE CENTER OF SFC HIGH PRES ASSOCIATED WITH UPPER RIDGE WL MOVE FROM NRN ONTARIO INTO NRN MN BY THU MORNING SO WOULD EXPECT THE WRN FCST AREA TO BE COOLEST TONIGHT. RADIATIONAL COOLING UNDER CLEAR SKIES WILL ALSO BE ENHANCED BY DRY AIRMASS WITH PRECIPITABLE WATER VALUES AROUND 0.5 INCHES OR UNDER 60PCT OF NORMAL FOR THIS TIME OF YEAR. WILL CONTINUE TO GO BLO COOLEST MOS GUIDANCE OVER THE INTERIOR W (LOW/MID 40S) PER GOING FCST. FARTHER TO THE E OF THE HIGH...WINDS SHOULD MIX SOME OVER THE ERN FCST AREA...AND THERE MAY BE A SOME MIDLEVEL CLOUDS WRAPPING S AROUND LOW OVER SE CANADA LOW. WILL STAY CLOSE TO MOS GUIDANCE THERE WITH UPPER 50S ALONG LAKE SUPERIOR AND LOW TO MID 50S INLAND. KEPT IN PATCHY FOG OVER THE INTERIOR W HALF WHERE LIGHT/CALM WINDS AND CHILLY AIR OVERNIGHT COULD GENERATE GROUND FOG AROUND INLAND LAKES/STREAMS AND LOW-LYING AREAS. UPR RDG AXIS WILL SETTLE S INTO THE UPPER LAKES ON FRI. AT THE SFC...ASSOCIATED HIGH PRES WILL DRIFT SLOWLY S BY LATE FRI AS THE CORE OF THE DRY AIRMASS MOVES OVER THE FCST AREA DURING THE AFTN PRECIPITABLE WATER VALUES FALL TO AROUND 0.5 INCHES OVER MUCH OF THE AREA. EXPECT SUNNY SKIES TO DOMINATE FOR THE MOST PART WITH VERY LIMITED CU OVER INLAND AREAS. EXPECT DEEP MIXING TO AROUND 750MB UNDER THE DRY AIRMASS. FCST SOUNDINGS INDICATE MAX TEMPS FRI WILL BE A COUPLE OF DEGREES HIGHER AND DWPTS A COUPLE OF DEGREES LWR AS DRIER/WARMER AIR MIXES TO THE SFC. RH`S VALUES COULD FALL TO AROUND 25PCT WELL INLAND FROM LAKE SUPERIOR WHICH COULD BE A CONCERN FOR WILDFIRE POTENTIAL. FORTUNATELY WINDS WILL BE RELATIVELY LIGHT WITH HIGH PRES IN THE VCNTY. .LONG TERM...FRIDAY NIGHT AND LATER A BROAD MID LEVEL RIDGE REMAINS OVER THE WEST HALF OF THE CONUS AND WESTERN CANADA AND A LONGWAVE TROUGH OVER SE CANADA/NEW ENGLAND. MAIN UPPER JET IS OVER HUDSON BAY. A WEAK SHORTWAVE WILL TRACK SOUTHEAST THROUGH NORTHERN ONTARIO TO QUEBEC ON SATURDAY. WARM AIR ADVECTION WILL RESULT IN SOME CLOUD COVER THOUGH. DRY WEATHER WILL CONTINUE RIGHT THRU SUNDAY. MAX TEMPS OVER THE WEEKEND SHOULD BE IN THE 80S IN MOST AREAS WITH SUNDAY BEING THE WARMEST DAY (IN THE MID 80S) AS 850MB THERMAL RIDGE SETTLES OVER THE AREA AHEAD OF COLD FRONT WHICH WILL DROP SOUTH TOWARD THE UPPER GREAT LAKES. THERE SHOULD BE ENOUGH HEIGHT FALLS HEADING THROUGH SOUTHEAST CANADA TO SEND THAT FRONT INTO THE UPPER GREAT LAKES ON MONDAY...PROVIDING THE POSSIBILITY OF A FEW SHRA/TSRA AT THAT TIME. A BROAD RIDGE WILL CONTINUE TO BUILD OVER THE WEST HALF OF THE CONUS SUNDAY NIGHT AND MONDAY...WHILE A LONGWAVE TROUGH STRETCHES FROM NORTHEAST QUEBEC SOUTHWEST INTO EAST CENTRAL ONTARIO. A WEAK SHORTWAVE WILL SWEEP THROUGH EASTERN ONTARIO. A COLD FRONT WILL SHIFT SOUTH ACROSS THE FORECAST AREA. A SURFACE RIDGE WILL BUILD BEHIND THE FRONT OVER MANITOBA AND NORTHERN ONTARIO. MOST OF THE INSTABILITY AND LOW LEVEL MOISTURE WILL BE OVER EASTERN ONTARIO. WITH THE SURFACE INSTABILITY FROM THE FRONT AND WEAK SHORTWAVE ENERGY EAST WILL NOT RULE OUT COMPLETELY A CHANCE OF SHOWERS AND THUNDERSTORMS...SO WILL CALL FOR A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS MAINLY OVER LAKE SUPERIOR. THE BROAD RIDGE AND LONGWAVE TROUGH WILL REMAIN IN PLACE THROUGH TUESDAY NIGHT. THE SURFACE RIDGE WILL PUSH INTO THE FORECAST AREA MONDAY NIGHT AND TUESDAY AS THE FRONT WORKS INTO SOUTHERN LOWER MICHIGAN BRINGING DRY AIR TO THE REGION. UNDER DRY STABLE AIR...CONDITIONS WILL REMAIN DRY. A WEAK WARM FRONT WILL SWEEP INTO THE FORECAST AREA ON WEDNESDAY. ECMWF IS CALLING FOR A WEAK SHORTWAVE ENTERING THE AREA AS WELL. MOISTURE WILL REMAIN RATHER LIMITED. THUS WILL KEEP JUST A SLIGHT CHANGE OF SHOWERS AND THUNDERSTORMS FOR WEDNESDAY. && .AVIATION (FOR THE 06Z TAF ISSUANCE)... HIGH PRESSURE WILL CONTINUE TO CONTROL THE WEATHER AT BOTH SITES THROUGH THE PERIOD...RESULTING IN VFR CONDITIONS THROUGH THE FORECAST PERIOD. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... SFC HIGH PRESSURE OVER NORTHWEST ONTARIO IS EXPECTED TO SETTLE OVER THE WRN GREAT LAKES LATE TONIGHT INTO FRIDAY. EXPECT NORTHEAST WINDS TO OVER FAR WESTERN LAKE SUPERIOR TO GRADUALLY DIMINISH IN INTENSITY LATER THIS EVENING (BLO 15 KT) AS THE SFC HIGH BECOMES MORE CENTERED OVER THE REGION. AS THE HIGH PRESSURE RIDGE MOVES SOUTH OF THE AREA SATURDAY AND SUNDAY. STRONGER WINDS...UP NEAR 25 KNOTS...SEEM POSSIBLE ON SATURDAY IN THE TIGHTER PRESSURE GRADIENT ON THE NORTH SIDE OF THE RIDGE. OTHERWISE...WINDS WILL REMAIN 20 KNOTS OR LESS INTO EARLY NEXT WEEK. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...JV LONG TERM...DLG AVIATION...RJT MARINE...JV mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 1125 AM CDT SAT AUG 16 2008 .UPDATE...LATEST SURFACE ANALYSIS HAS THE QUASI-STATIONARY FRONT TO OUR SOUTH ALONG INTERSTATE 10 WHILE THE WEAK BOUNDARY IN THE NORTH REMAINS JUST NORTH OF OUR CWFA. REGIONAL RADARS SHOWS SHOWERS CONTINUING IN THE NORTH...NORTH OF HIGHWAY 82 AND THESE SHOULD DROP SOUTH THIS AFTERNOON INTO OUR NORTHERN ZONES. SCATTERED SHOWERS AND THUNDERSTORMS WERE NOTED IN THE SOUTH...SOUTH OF HIGHWAY 84 WITH WEAK IMPULSES COMBING WITH STALLED FRONT. SOME OF THIS ACTIVITY IS EXPECTED TO SPREAD NORTH INTO OUR SOUTHERN ZONE THIS AFTERNOON. THE GFS HAS CONTINUED TO OVERDUE THE PRECIPITATION ACROSS THE CENTRAL PORTIONS OF OUR CWFA THIS MORNING. WATER VAPOR IMAGERY/RUC ANALYSIS SHOWS SHORTWAVES OVER THE MIDDLE MISSISSIPPI VALLEY...SOUTHERN PLAINS AND GULF COAST BUT NONE TO DIRECTLY INFLUENCE OUR CWFA THIS AFTERNOON. HAVE THUS CANCELED THE FLASH FLOOD WATCH THAT WAS IN EFFECT. HAVE LOWERED POPS IN THE CENTRAL BUT INCREASED POPS SOME NORTH AND SOUTH. MAX TEMPS IN THE NORTH WILL HAVE A HARD TIME REACHING LOWER 80S SO HAVE TRIMMED OFF SEVERAL DEGREES THERE THIS AFTERNOON. BEST CHANCE FOR ANY STRONG THUNDERSTORM TODAY APPEARS TO BE IN THE SOUTH SO HAVE KEPT WORDING IN THE HWO. UPDATES HAVE BEEN POSTED. /22/ I && .PREVIOUS DISCUSSION...SHORT TERM...THE BAND OF HEAVIER RAINFALL OVER NRN ZONES WILL CONTINUE TO WEAKEN THIS MORNING. TRAINING CELLS OVER THAT AREA HAVE PRODUCED LOCAL RAINFALL RATES FROM 2-3 INCHES AN HOUR. THE PLACEMENT OF THE FRONTAL BOUNDARY WILL BE THE DETERMINING FACTOR IN WHERE THE BEST RISK OF HEAVIER RAINFALL WILL OCCUR DURING THE DAY. PRECIPITABLE WATER VALUES WILL GENERALLY RANGE FROM 1.5 TO 2 INCHES TODAY...SUFFICIENT MOISTURE FOR PERIODS OF HEAVY RAINFALL GIVEN SUFFICIENT FORCING. GENERAL MODEL CONSENSUS IS THAT FRONTAL FORCING WILL SHIFT FARTHER SOUTH DURING THE DAY. THIS IS SUPPORTED BY UPPER TROUGHING THAT PIVOTS SWD AROUND THE EDGES OF THE ERN U.S. LOW. WILL FOLLOW MOS WITH HIGHEST POPS OVER ECENTRAL ZONES TODAY AS THE BOUNDARY SHIFTS SWD. ALSO OF CONCERN IS EVIDENCE OF PREDAWN MESOSCALE CIRCULATION NOTED IN VICINITY OF MS/AL BORDER. LINGERING MESOSCALE EFFECTS...INCLUDING OUTFLOW BOUNDARIES...MAY SERVE AS A FOCUS FOR CONVECTION THIS AFTERNOON. THE ABSENCE OF A PREDAWN COMPLEX OR SIGNIFICANT WAVE TO PROVIDE WIDESPREAD LIFT SHOULD RESULT IN THE FLOODING RISK BEING MORE LOCALIZED IN NATURE. WILL MAINTAIN CURRENT FLASH FLOOD WATCH FOR NOW BUT EXPECT IT TO BE WHITTLED DOWN SOMETIME DURING THE DAY AS THE BOUNDARY DROPS SWD. COOLER MOS HIGHS LOOK ON TRACK FOR TODAY. WILL SEE LOCALLY COOLER SPOTS DEPENDING ON LOCATIONS OF HEAVIER RAINFALL...ESPECIALLY DURING THE EARLY AFTERNOON. STRONGER SURFACE TROUGHING BEGINS TO SHIFT EAST OF THE AREA TONIGHT...RESULTING IN DECREASING LOW LEVEL CONVERGENCE AND A DECREASING CHANCE OF RAINFALL OVERNIGHT. /03/ SUNDAY STILL LOOKS LIKE IT COULD BE A LITTLE BIT WET ACROSS THE SOUTH BUT THE RAIN CHANCES WILL BE ON THE WAY DOWN COMPARED TO SAT. MOISTURE WILL BE PUSHED TO THE SOUTH AS OUR FRONT MOVES BACK TOWARDS THE GULF AND HIGH PRESSURE AT THE SFC SLOWLY WORKS A LITTLE FURTHER SOUTH FROM THE CNTRL CONUS. WE WILL ALSO BE IN BETWEEN DISTURBANCES. THE DISTURBANCE FROM THE ERN CONUS TROUGH WILL PUSH EAST OF THE AREA AND THE FIRST OF MANY WAVES FROM THE UPPER LOW MOVING EAST OF THE ROCKIES WILL STILL BE OFF TO OUR WEST AND THIS WILL HELP KEEP RAIN CHANCES DOWN A LITTLE SUN. LONG TERM...THE EXTENDED PORTION OF THE FORECAST CONTINUES TO BE RATHER DIFFICULT WITH VERY LITTLE CONFIDENCE IN THE FORECAST. MDLS CONTINUE TO HAVE A DIFFICULT TIME FIGURING OUT HOW TO HANDLE THE UPPER LOW OVER THE ROCKIES...THE UPPER PATTERN OVER THE ERN CONUS AND WHAT EFFECTS THAT WILL HAVE ON TROPICAL STORM FAY. WITH THIS I WILL STICK PRETTY CLOSE TO THE MEX GUI VALUES WITH A LEAN TOWARDS THE ENSEMBLE MEAN POP VALUES ON A FEW DAYS ESPECIALLY SINCE THE GFS HAS TRENDED A LITTLE WETTER AGAIN. FOR MOST OF NEXT WEEK THE MAIN INFLUENCE TO OUR SENSIBLE WEATHER WILL BE THE UPPER LOW THAT APPEARS WILL MOVE INTO THE SRN PLAINS WHICH IS FURTHER SOUTH AND SLOWER THAN WHAT THE MDLS WERE EXPECTING 24 HRS AGO. IN ADDITION THE MDLS ARE NOT BUILDING IN THE RIDGE OVER THE SERN/ERN CONUS NOW UNTIL MUCH LATER IN THE WEEK. AS MENTIONED LAST NIGHT IF BOTH OF THOSE FACTORS CHANGED TOWARDS WHAT IS BEING ADVERTISED NOW THE FORECAST WOULD NEED TO SHOW BETTER RAIN CHANCES. THIS IS NOW THE CASE AS THE MEX IS A GOOD BIT HIGHER WITH THE POPS THROUGHOUT MOST OF THE WEEK. THIS LOOKS BETTER BUT I WILL STILL MAKE SOME CHANGES TO MON AND GO CLOSER TO THE ENS MEAN WHICH IS A BIT HIGHER. THE UPPER LOW WILL SLOWLY MOVE INTO THE SRN PLAINS LATE TUE/EARLY WED AND THEN BEGIN TO OPEN UP AND LIFT OUT TO THE NE THU. THIS WILL BRING THE POSSIBILITY OF NUMEROUS WAVES MOVING ACROSS THE AREA. MOISTURE WILL BE IN NO SHORT SUPPLY AND THIS WOULD HELP KEEP SCT SHRA AND TSRA POSSIBLE EACH DAY WITH ACTIVITY NOT COMPLETELY DIURNALLY DRIVEN. TEMPERATURES WILL LIKELY REMAIN VERY SIMILAR THROUGHOUT THE WEEK WITH HIGHS IN THE UPPER 80S TO NEAR 90 AND LOWS IN THE MID TO UPPER 60S. THE OTHER CONCERN OF COURSE IS TROPICAL STORM FAY WHICH IS CURRENTLY MOVING OVER HAITI. THIS SYSTEM IS FORECASTED TO MOVE INTO THE ERN GULF OF MEXICO...BECOME A HURRICANE AND TRACK JUST WEST OF THE FL PENINSULA MOVING INTO THE ERN HALF OF THE PANHANDLE WED. THAT SAID THERE ARE SOME DIFFERENCES IN THE MDLS SO WE WILL NEED TO KEEP A CLOSE EYE ON THE SYSTEM TO SEE IF THERE IS ANY CHANCE OF IT GETTING FURTHER WEST. /CAB/ && .AVIATION...UPDATED...WE WILL SEE OCCASIONAL MVFR CIGS/VSBY IN PATCHES OF RAIN AND MIST THROUGH THE MIDDAY HOURS...WITH BRIEF IFR CONDITIONS IN AREAS OF HEAVIER SHRA AND TSRA. OTHERWISE BKN-OVC CIGS FROM 1250 TO 2500 FEET FROM A GLH TO HBG LINE AND POINTS SOUTH AND WEST...AND CIGS 2500 TO 5000 FEET NORTH AND EAST...WITH MULTIPLE CLOUD LAYERS EXTENDING UP TO 25 KFT. SCATTERED SHRA AND ISOLATED TSRA WILL INCREASE WITH GREATER COVERAGE EXPECTED AFTER 20Z. LIGHT TURBULENCE CAN ALSO BE EXPECTED. CONVECTION WILL DECREASE IN COVERAGE AND INTENSITY THIS EVENING WITH ISOLATED SHRA MAINLY SOUTH OF A JAN TO MEI LINE BY MIDNIGHT. /DH/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 82 66 86 65 / 73 27 36 14 MERIDIAN 82 65 87 65 / 73 34 34 14 VICKSBURG 83 68 87 66 / 67 21 36 13 HATTIESBURG 85 70 88 67 / 85 33 37 22 NATCHEZ 83 68 86 67 / 66 20 31 22 GREENVILLE 80 66 89 65 / 60 19 19 10 GREENWOOD 80 65 90 64 / 65 24 18 10 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ 22/03/CAB/DH ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPRINGFIELD MO 1141 PM CDT THU AUG 14 2008 ...UPDATE TO AVIATION... .UPDATE... A FEW SHOWERS REMAIN FROM THIS EVENINGS CONVECTION AND THIS AREA OF PRECIPITATION WILL SHIFT EAST OF THE AREA DURING THE OVERNIGHT. CONVECTION TO THE WEST WILL REMAIN SOUTHWEST OF THE AREA OVERNIGHT AND AM NOT EXPECTING ADDITIONAL REDEVELOPMENT OVERNIGHT. HAVE SIGNIFICANTLY REDUCED POPS OVERNIGHT. MAY HAVE TO MONITOR THE FOG POTENTIAL OVERNIGHT AND FOR STARTERS HAVE THROWN IN 2SM FOR THE WESTERN CWA DURING THE OVERNIGHT PERIOD. ZONES/GRIDS HAVE ALREADY BEEN SENT. LINDENBERG && .DISCUSSION... PRECIPITATION OVER NORTHEAST KANSAS AND NORTHWEST MISSOURI WAS OCCURRING IN RESPONSE TO AN UPPER LEVEL SHORTWAVE THAT EXISTED OVER NORTHEAST KANSAS. 310K ISENTROPIC SURFACE INDICATED 15 TO 20 KNOT PARCEL FLOW OVER A MESO-SCALE BAND OF BAROCLINICITY ACROSS EASTERN KANSAS. THE EVOLUTION AND MOVEMENT OF THIS AREA OF PRECIPITATION WAS THE INITIAL FORECAST CHALLENGE. OTHER CHALLENGES EXTENDED INTO FRIDAY AND FRIDAY NIGHTS PERIOD...AS ADDITIONAL SHOWER AND THUNDERSTORM CHANCES WERE WARRANTED. SHORT TERM (TONIGHT - FRIDAY NIGHT)... I`M GOING TO MAKE A LAST MINUTE CALL ON TONIGHTS PRECIPITATION CHANCES. WILL WAIT AND SEE HOW THE ONGOING CONVECTIVE CLUSTER IN NORTHERN MISSOURI IS TRENDING ON RADAR. ULTIMATELY NOT A SINGLE COMPUTER MODEL HAS A SNIFF ABOUT WHATS GOING ON RIGHT NOW...LET ALONE IN THE FUTURE. BASED ON RADAR AND MOISTURE CHANNEL IMAGERY TRENDS...PRECIPITATION CHANCES WILL NEED TO BE INCREASED FOR TONIGHTS PERIOD. ALSO HAVE SOME CONCERNS REGARDING INSTABILITY TRENDS OVER EASTERN KANSAS/WESTERN MISSOURI. RUC MIXED LAYER CAPE INDICATES VALUES OF AROUND 1500 J/KG WITH NO CAP. FORCING FROM THE NE KANSAS UPPER LOW INTERACTING WITH THIS CAPE COULD YIELD ANOTHER CONVECTIVE CLUSTER THATS NOT INDICATED BY THE MODELS. FRIDAYS PRECIP CHANCES ARE TOTALLY DEPENDENT UPON HOW TONIGHTS CONVECTION EVOLVES. THEREFORE HAVE LEFT CHANCE TO LIKELY POPS IN FOR FRIDAYS DAY PERIOD. RAIN CHANCES WILL END FRIDAY NIGHT AS A MUCH DRIER AND MORE STABLE AIRMASS SPREADS IN FROM THE UPPER MIDWEST. HAVE DECREASED FRIDAY NIGHTS RAIN CHANCES. LONG TERM (SATURDAY - WEDNESDAY)... MADE SOME SERIOUS ADJUSTMENTS WITH SATURDAY - TUESDAYS POPS. THE MAIN SYNOPTIC UPPER LOW IS TRACKING SOUTHWARD ACROSS THE NORTHERN PLAINS...AND WILL LIKELY STALL OUT OVER THE HIGH PLAINS OF COLORADO/KANSAS. THIS POSITIONING WILL BE TOO FAR WEST FOR HIGH PRECIPITATION CHANCES IN MISSOURI. AS A MATTER OF FACT...I DECIDED TO COMPLETELY TAKE OUT POPS FOR THESE PERIODS...AS THE ENTIRE WEEKEND SHOULD BE DRY FOR EXTREME SOUTHEAST KANSAS AND THE MISSOURI OZARKS. AS THE UPPER LOW WEAKENS HEADING INTO EARLY TO MID NEXT WEEK...THE SHEAR AXIS IS PROGGED TO REMAIN WEST OF THE CWA. THIS WOULD ALLOW TROPICAL AIR TO SPREAD BACK IN A RETURN OF RAIN CHANCES IN THE FORECAST WILL BE NEEDED BY TUESDAY NIGHT OR WEDNESDAY OR NEXT WEEK. REGARDING TEMPERATURES...CLOUD COVER ALONG WITH THE CHANGE IN AIRMASS WILL LIMIT READINGS FROM WARMING OUT OF THE LOW TO MID 80S FOR BOTH SATURDAY AND SUNDAY. WARMER TEMPERATURES WILL BE ON TAP FOR NEXT WEEK AS THE GULF AIRMASS FILTERS IN. CRAMER && .AVIATION... FOR THE 06Z TAFS...MAIN AREA OF SCATTERED SHOWERS SHOULD REMAIN EAST OF THE SGF/JLN TERMINAL LOCATIONS OVERNIGHT. QUESTION WILL BE IF ENOUGH CLEARING CAN TAKE PLACE FOR FOG TO DEVELOP. FOR NOW WILL HAVE VISIBILITIES DROP TO AROUND 4SM WITH A TEMPO GROUP DOWN TO 2SM BETWEEN 11Z AND 12Z. HAVE CEILINGS HANGING AROUND 5000 FEET WITH A TEMPO GROUP OF 2500 FEET. LINDENBERG && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 200 AM EDT SAT AUG 16 2008 .SYNOPSIS... A PERSISTENT UPPER LEVEL STORM SYSTEM OVER SOUTHEAST CANADA, WILL KEEP WIDELY SCATTERED SHOWERS AND THUNDERSTORMS OVER NEW YORK AND PENNSYLVANIA THROUGH SATURDAY MORNING. HIGH PRESSURE WITH DRIER WEATHER WILL BE OVER THE REGION SATURDAY AFTERNOON THROUGH MONDAY. && .NEAR TERM /UNTIL 7 AM THIS MORNING/... UPDATE AS OF 730 PM...LATEST RUC ANALYSIS AND PROGS SHOW THAT BEST PVA WILL BE OVER NEPA AND SE NY OVERNIGHT AS UL LOW DROPS INTO CNY. 18Z GFS/NAM ALSO CONCUR WITH THIS IDEA. SFC BASED INSTABILITY WILL BE GONE SO REALLY NOT EXPECTING MUCH MORE THAN ISOLD SPRINKLES/SHOWERS FROM AC CLOUD DECKS WITHIN THE UPPER LOW ONCE THIS EARLY EVENING CONVECTION PASSES BY. MAY LEAN WITH SLIGHTLY HIGHER POPS IN THE EAST AND SE ZONES GIVEN BETTER FORCING AND TERRAIN FEATURES...BUT ELSEWHERE WILL BE TRIMMING BACK PRECIP CHANCES AND CLOUD COVER TO P/C. GRIDS WILL BE UPDATED DURG NEXT HOUR WITH FRESH ZFP AROUND 9 PM. && .SHORT TERM /7 AM THIS MORNING THROUGH MONDAY/... MAIN UPPER TROF CONTINUES TO MOVE EWD ACROSS THE FA EARLY SATURDAY, BEFORE MOVING EAST OF THE AREA DURING THE AFTN. KEPT CHC POPS ACROSS MUCH OF UPSTATE IN THE MORNING, THEN JUST ACROSS THE ERN ZONES INTO THE AFTN. LOOKS LIKE WE CAN SQUEAK OUT A DECENT DAY ON SUNDAY, ALTHOUGH SOME TROFINESS DIGGING SWD MAY BRING INCREASE IN CLDS. KEPT ANY PRECIP CHC OUT AT THIS POINT. LOOKS LIKE NEXT CHC AT MORE ORGANIZED SHRA MAY COME LATER MONDAY AS FRONT APPROACHES FROM THE NORTH. && .LONG TERM /TUESDAY THROUGH FRIDAY/... CURRENT THINKING REFLECTS LITTLE OR NO CHANGES TO PREVIOUS MEDIUM- RANGE FORECAST UPDATE. THE PASSAGE OF A WEAK COLD FRONT LATER MONDAY NIGHT INTO TUESDAY COULD BRING AT LEAST SCATTERED CONVECTION...HENCE A CONTINUED CHANCE OF SHOWERS OR THUNDERSTORMS. FROM MID-WEEK ONWARD...A BUILDING EASTERN U.S. UPPER-LEVEL RIDGE IS WELL AGREED UPON BY OUR SUITE OF MEDIUM-RANGE MODELS. THUS... MAINLY RAIN-FREE CONDITIONS AND WARMING TEMPERATURES ARE FORESEEN. ONE POTENTIAL WILD-CARD THIS PERIOD IS WHERE TROPICAL MOISTURE FROM FAY OR ITS REMNANTS WILL BE DIRECTED TOWARDS. EARLY INDICATIONS ARE THAT MUCH OF IT MAY REMAIN TO OUR SOUTH AND WEST...FOR THE BETTER PART OF NEXT WEEK. THUS...WE`LL BASICALLY STICK WITH A DRY FORECAST...AND INDICATE THE RETURN OF MORE TYPICAL MID TO LATE SUMMER TEMPERATURES (WELL INTO THE 80S BY LATER IN THE WEEK). && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... LOWER CEILINGS AND FOG EXPECTED TO FORM AT KELM AND KAVP EARLY THIS MORNING...WITH IFR ANTICIPATED AT THESE SITES. IMPROVEMENT BACK TO VFR PROGGED FOR THE 12Z-14Z TIME FRAME. OTHERWISE...VFR SHOULD PREVAIL TODAY. WIDELY SCATTERED SHOWERS AND THUNDERSTORMS MAY FORM IN THE VICINITY OF KRME THIS AFTERNOON...BUT COVERAGE LOOKS ISOLATED ENOUGH AT THIS TIME RANGE TO PRECLUDE ITS MENTION IN THE TERMINAL FORECAST. LIGHT WINDS EARLY TODAY...WILL BECOME WEST TO NORTHWEST AT CLOSE TO 10 KT THIS AFTERNOON. OUTLOOK... SATURDAY NIGHT THRU WEDNESDAY...VFR...WITH POSSIBLE IFR FOG IN THE MORNING...ESPECIALLY AT ELM. A FRONTAL BOUNDARY MAY BRING CHC FOR SHRA/TSRA ON TUESDAY. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...JML NEAR TERM...JAB SHORT TERM...JML LONG TERM...MLJ/TAC AVIATION...MLJ/JAB ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC 1103 AM EDT FRI AUG 15 2008 .SYNOPSIS... WEAK LOW PRESSURE WILL PASS TO THE SOUTH AND EAST OF THE AREA TODAY. A WEAK FRONT WILL APPROACH FROM THE NORTHWEST TONIGHT AND MOVE INTO EASTERN NORTH CAROLINA SATURDAY. THE FRONT WILL BECOME STATIONARY TO THE SOUTH SUNDAY AND MONDAY...THEN DISSIPATE TUESDAY. A BACKDOOR FRONT WILL APPROACH WEDNESDAY AND MOVE INTO THE AREA THURSDAY. A TROPICAL SYSTEM MAY AFFECT THE AREA LATE IN THE WEEK. PLEASE REFER TO FORECASTS AND DISCUSSIONS ISSUED BY THE TROPICAL PREDICTION CENTER. && .NEAR TERM /THROUGH TONIGHT/... TWEAKED CLOUD COVER AND POPS THIS UPDATE TO REFLECT MOSTLY SUNNY SKIES BECOMING PARTLY CLOUDY THIS AFTERNOON. WEAK SEA BREEZE DEVELOPS THIS AFTERNOON BUT CONVERGENCE ALONG IT WILL BE VERY WEAK SO WILL ONLY MENTION ISOLATED CONVECTION GENERALLY EAST OF THE HWY 17 CORRIDOR. WEAK COLD FRONT WILL SLOWLY APPROACH FROM THE NW THIS AFTERNOON WITH CONVECTION EXPECTED TO FORM ALONG THIS BOUNDARY OVER SOUTHERN VA AND NORTH CENTRAL NC. WILL KEEP CHANCE POPS OVER THE COASTAL PLAIN WITH SHRA/TS POSSIBLE MAINLY LATE AFTERNOON INTO THE EVENING HOURS. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... WEAK COLD FRONT WILL MOVE SLOWLY SE TONIGHT. KEPT CHANCE POPS ALONG THE COASTAL PLAINS COUNTIES AND LEFT SLIGHT CHANCE OVER THE REMAINDER. BROADBRUSHED 40 PERCENT ACROSS THE ENTIRE AREA ON SATURDAY WITH THE FRONT MOVING THROUGH THE AREA. THE FRONT WILL MOVE TO THE SOUTH AND EAST SUNDAY NIGHT...BECOMING STATIONARY JUST LIKE THE PREVIOUS ONE ACROSS THE GULF STATES AND SOUTH GEORGIA...JUST LIKE THE PREVIOUS ONE. && .LONG TERM /MONDAY THROUGH THURSDAY/... HIGH PRESSURE WILL EXTEND ACROSS THE AREA SUNDAY NIGHT INTO MONDAY NIGHT SO I WENT WITH A DRY FORECAST. BY TUESDAY THE FRONT WILL DISSIPATE AND THE HIGH WILL WEAKEN. DEWPOINTS WILL BE ON THE RISE WITH A RETURN TO MAINLY AFTERNOON/EVENING CONVECTION. A BACKDOOR COLD FRONT WILL APPROACH TUESDAY NIGHT AND ENTER THE STATE ON WEDNESDAY. LEFT POPS AT SLIGHT CHANCE. BIG QUESTION MARK FOR THE END OF THE WEEK WITH A TROPICAL SYSTEM POSSIBLY AFFECTING THE AREA. && .AVIATION /15Z FRIDAY THROUGH TUESDAY/... EXPECTING VFR CONDITIONS OUTSIDE OF ISOLATED LATE DAY THUNDERSTORMS THIS AFTERNOON. A WEAK FRONT WILL MOVE EAST ACROSS THE AREA OVERNIGHT WITH SCATTERED SHOWERS AND STORMS AND THE POTENTIAL FOR MVFR/IFR CONDITIONS AFTER MIDNIGHT THROUGH 15Z SATURDAY. AFTER THE PASSAGE OF THIS FEATURE CONDITIONS WILL RETURN TO MAINLY VFR SATURDAY AFTERNOON/EVENING WITH ONLY ISOLATED CONVECTION POSSIBLE. PATCHY DENSE FOG A POSSIBILITY SUNDAY MORNING...ESPECIALLY IN AREAS THAT RECEIVE RAINFALL SATURDAY MORNING. ONLY ISOLATED THUNDERSTORMS ARE EXPECTED MONDAY AND TUESDAY. && .MARINE... WEAK GRADIENT CURRENTLY OVER WATERS WITH WEAK LOW WELL OFF THE COAST AND WEAK HIGH PRESSURE INLAND. FLOW IS CURRENTLY N/NE 5-10 KT AND IS EXPECTED TO BECOME SE 10 KT THIS AFTERNOON. 2-3 FT 8-10 SECOND PERIOD SWELL IS EXPECTED TO CONTINUE THROUGH THIS EVENING. ONLY CHANE TO CURRENT FORECAST WAS TWEAK WIND DIRECTIONS AND LIMIT INCREASE IN WINDS THIS AFTERNOON TO 10 KT BASED ON LATEST NAM/RUC MODELS. WEAK LOW PRES OFF THE SC COAST WILL MOVE OUT INTO THE WESTERN ATLC TODAY. WINDS BACKING TO THE SE/E OVR THE MARINE AREA BUT SPEEDS GENERALLY LIGHT AT 12 KTS OR LESS. WINDS SHIFTING BACK SW/W AHEAD WEAK SFC BNDRY TNGT THEN BECOMING MORE W/NW AS BNDRY SLIPS THRU MARINE AREA ON SAT. AGAIN WIND SPEEDS MAINLY LIGHT THRUOUT GIVEN THE WEAK PGRAD AND CAA. PSBLY A PROLONGED PERIOD OF NE/E WINDS SETTING UP BY LATE IN THE WEEKND THRU EARLY NEXT WEEK AHEAD TROPICAL SYSTEM MOVING THRU THE BAHAMAS. WILL NEED TO MONITOR INCOMING SWELL OUT AHEAD OF THIS SYSTEM. LATEST HI RES WNA HOLDS OFF BRINGING IN SMALL CRAFT ADVISORY THRESHOLD SEAS (6 FT) UNTIL LATE TUESDAY NIGHT/EARLY WED BUT MAY BE TOO SLOW IF SYSTEM STRENGTHENS SIGNIFICANTLY. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...NONE. && $$ SYNOPSIS...HSA NEAR TERM...JW SHORT TERM...HSA LONG TERM...HSA AVIATION...JME MARINE...JME nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CLEVELAND OH 755 PM EDT FRI AUG 15 2008 .SYNOPSIS... A DISTURBANCE JUST NORTH OF LAKE ERIE WILL DROP SOUTH ACROSS THE REGION THIS EVENING AND TONIGHT. BEHIND THE SYSTEM...HIGH PRESSURE WILL BUILD IN FOR SATURDAY AND SUNDAY. MONDAY A WEAK COLD FRONT WILL DROP SOUTH THROUGH THE AREA. && .NEAR TERM /THROUGH SATURDAY/... CLOSED UPPER LOW CENTERED OVER LAKE ONTARIO THIS AFTERNOON. CONVECTION HAS BROKEN OUT MOSTLY NORTH OF LAKE ERIE AND IN EASTERN LOWER MICHIGAN. MAIN CONCERN IS WILL THE CONVECTION SURVIVE CROSSING LAKE ERIE. RUC AND NAM SHOW MOST UNSTABLE AIR NORTH OF THE AREA THIS AFTERNOON AND AS THE AREA SHIFTS SOUTH THE INSTABILITY SHOULD DECREASE WITH DIURNAL TENDENCIES. HOWEVER MODELS ALSO SHOW AM UPPER WAVE MOVING ACROSS THE AREA THIS EVENING. BELIEVE THIS FORCING WILL BE ENOUGH FOR SCATTERED CONVECTION TO EITHER SURVIVE OR JUMP THE LAKE THIS EVENING. SO FOR TONIGHT WILL GO WITH CHC POPS NORTHEAST AND SLIGHT CHC ELSEWHERE. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... SATURDAY...THE BACK SIDE OF TONIGHTS UPPER FORCING MOVES OUT OF THE AREA. AT THE SURFACE...HIGH PRESSURE IS NOSING IN FROM THE WEST. AND SHOULD PROVIDE SUBSIDENCE. AIRMASS WILL BE FAIRLY DRY AND MORE STABLE WITH THE UPPER LOW HAVING WEAKENED TO AN OPEN WAVE AND PULLED EAST. THUS EXPECT SUNNY/PARTLY CLOUDY SKIES WITH AFTERNOON TEMPERATURES A COUPLE DEGREES WARMER THAN TODAY. SUNDAY MODELS SHOW A ANOTHER SHORT WAVE MOVING THROUGH THE AREA WITH AT LEAST SOME MOISTURE ASSOCIATED WITH IT. GFS KEEPS MOST UNSTABLE AIR NORTH OF THE AREA HOWEVER AND WITH A BROAD UPPER TROF AXIS EAST OF THE AREA AND INCREASING HEIGHTS AND HIGH PRESSURE AT THE SURFACE...WILL FOR NOW CONTINUE WITH A DRY FORECAST. DID HOWEVER THROW IN A 20% POP FOR THE GRAPHICS. THROUGH THE PERIOD EXPECT A SLOW WARMING TREND AS THE AIRMASS RECOVERS WARM ADVECTION TAKING PLACE FROM THE NORTHWEST OUT OF THE UPPER RIDGE OVER THE UPPER PLAINS AND ROCKY MOUNTAIN REGION. SUNDAY NIGHT A WEAK COLD FRONT WILL APPROACH THE AREA FROM THE NORTH. WILL KEEP A SLIGHT CHANCE IN GRAPHICS FOR THE FAR NORTHEAST. ELSEWHERE WILL GO DRY. && .LONG TERM /MONDAY THROUGH FRIDAY/... PATTERN LOOKS RATHER TRANQUIL OVER THE LONG TERM PERIOD OF THE FORECAST. HIGH PRESSURE IN CONTROL INITIALLY ON MONDAY GIVES WAY TO A WEAK FRONTAL BOUNDARY EXTENDING THROUGH CENTRAL MI TO NEW YORK STATE LOOKS TO DROP SOUTHWARD ACROSS THE AREA ON TUESDAY. AT THIS TIME ONLY HAVE SLIGHT CHC POPS SHOWN IN GRIDS. HIGH PRESSURE BUILDS INTO THE AREA FOR MIDWEEK KEEPING DRY AND SEASONABLE CONDITIONS FOR THE AREA THROUGH THURSDAY. WITH HIGH PRESSURE IN CONTROL THROUGH MUCH OF THE PERIOD...REMAINED CLOSE TO GUIDANCE TEMPS DURING THE PERIOD. ASIDE FROM MONDAY NIGHT THROUGH TUES NIGHT WITH THE FRONTAL BOUNDARY IN THE AREA...ONLY ISSUE WITH TEMPS WILL BE MINS IN THE EXTENDED WITH POSSIBLE RADIATING CONDITIONS ALLOWING RURAL LOCATIONS TO BE COOLER THAN FORECAST ESP FOR WED NIGHT. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... THE FEW SHOWERS THAT WERE OVER LERI AT MID AFTERNOON DISSIPATED EARLY THIS EVENING. DON`T EXPECT ANY SHOWERS/THUNDERSTORMS TO REDEVELOP OVERNIGHT. AREAS MVFR FOG LIKELY LATER TONIGHT AND EARLY SATURDAY MORNING WITH LOCAL OR ISOLATED AREA OF IFR CONDITIONS. OTHERWISE HIGH PRESSURE BUILDING IN AND GOOD VFR CONDITION WILL PREVAIL. OUTLOOK...ISOLATED THUNDERSTORMS POSSIBLE AS A WEAKENING FRONT APPROACHES LATE SUNDAY AFTERNOON AND EVENING. THEN AGAIN MONDAY NIGHT OR TUESDAY WITH ANOTHER WEAK FRONT DROPPING INTO THE AREA. HOWEVER VFR CONDITIONS SHOULD DOMINATE FOR MUCH OF THE PERIOD SATURDAY NIGHT THROUGH WEDNESDAY. && .MARINE... N TO NW FLOW MAY BE CLOSE TO SMALL CRAFT CONDITIONS AT TIMES TONIGHT AND SATURDAY BUT THINK 10 TO 20 KNOTS AND 2 TO 4 FOOT WAVES SHOULD BE THE TOP END. A SW FLOW AHEAD OF A WEAK COLD FRONT DUE OVER THE LAKE ABOUT MONDAY NIGHT MAY PICK UP TO 15 TO 20 KNOTS SOMETIME LATER SUNDAY INTO MONDAY AND PRODUCE 23 TO 5 FOOT WAVES BUT THE WINDS DIRECTIONS SHOULD KEEP THESE HIGHER WAVES IN THE OFFSHORE WATERS. THE PASSAGE OF THE FRONT MONDAY NIGHT SHOULD VEER THE SW WINDS TO A N THEN NE TO E DIRECTION TUE INTO WED. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...TK NEAR TERM...TK SHORT TERM...TK LONG TERM...ABE AVIATION...RANDEL MARINE...ADAMS oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CLEVELAND OH 235 PM EDT FRI AUG 15 2008 .SYNOPSIS...A DISTURBANCE JUST NORTH OF LAKE ERIE WILL DROP SOUTH ACROSS THE REGION THIS EVENING AND TONIGHT. BEHIND THE SYSTEM...HIGH PRESSURE WILL BUILD IN FOR SATURDAY AND SUNDAY. MONDAY A WEAK COLD FRONT WILL DROP SOUTH THROUGH THE AREA. && .NEAR TERM /THROUGH TONIGHT/... CLOSED UPPER LOW CENTERED OVER LAKE ONTARIO THIS AFTERNOON. CONVECTION HAS BROKEN OUT MOSTLY NORTH OF LAKE ERIE AND IN EASTERN LOWER MICHIGAN. MAIN CONCERN IS WILL THE CONVECTION SURVIVE CROSSING LAKE ERIE. RUC AND NAM SHOW MOST UNSTABLE AIR NORTH OF THE AREA THIS AFTERNOON AND AS THE AREA SHIFTS SOUTH THE INSTABILITY SHOULD DECREASE WITH DIURNAL TENDENCIES. HOWEVER MODELS ALSO SHOW AM UPPER WAVE MOVING ACROSS THE AREA THIS EVENING. BELIEVE THIS FORCING WILL BE ENOUGH FOR SCATTERED CONVECTION TO EITHER SURVIVE OR JUMP THE LAKE THIS EVENING. SO FOR TONIGHT WILL GO WITH CHC POPS NORTHEAST AND SLIGHT CHC ELSEWHERE. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... SATURDAY...THE BACK SIDE OF TONIGHTS UPPER FORCING MOVES OUT OF THE AREA. AT THE SURFACE...HIGH PRESSURE IS NOSING IN FROM THE WEST. AND SHOULD PROVIDE SUBSIDENCE. AIRMASS WILL BE FAIRLY DRY AND MORE STABLE WITH THE UPPER LOW HAVING WEAKENED TO AN OPEN WAVE AND PULLED EAST. THUS EXPECT SUNNY/PARTLY CLOUDY SKIES WITH AFTERNOON TEMPERATURES A COUPLE DEGREES WARMER THAN TODAY. SUNDAY MODELS SHOW A ANOTHER SHORT WAVE MOVING THROUGH THE AREA WITH AT LEAST SOME MOISTURE ASSOCIATED WITH IT. GFS KEEPS MOST UNSTABLE AIR NORTH OF THE AREA HOWEVER AND WITH A BROAD UPPER TROF AXIS EAST OF THE AREA AND INCREASING HEIGHTS AND HIGH PRESSURE AT THE SURFACE...WILL FOR NOW CONTINUE WITH A DRY FORECAST. DID HOWEVER THROW IN A 20% POP FOR THE GRAPHICS. THROUGH THE PERIOD EXPECT A SLOW WARMING TREND AS THE AIRMASS RECOVERS WARM ADVECTION TAKING PLACE FROM THE NORTHWEST OUT OF THE UPPER RIDGE OVER THE UPPER PLAINS AND ROCKY MOUNTAIN REGION. SUNDAY NIGHT A WEAK COLD FRONT WILL APPROACH THE AREA FROM THE NORTH. WILL KEEP A SLIGHT CHANCE IN GRAPHICS FOR THE FAR NORTHEAST. ELSEWHERE WILL GO DRY. && .LONG TERM /MONDAY THROUGH FRIDAY/... PATTERN LOOKS RATHER TRANQUIL OVER THE LONG TERM PERIOD OF THE FORECAST. HIGH PRESSURE IN CONTROL INITIALLY ON MONDAY GIVES WAY TO A WEAK FRONTAL BOUNDARY EXTENDING THROUGH CENTRAL MI TO NEW YORK STATE LOOKS TO DROP SOUTHWARD ACROSS THE AREA ON TUESDAY. AT THIS TIME ONLY HAVE SLGHT CHC POPS SHOWN IN GRIDS. HIGH PRESSURE BUILDS INTO THE AREA FOR MIDWEEK KEEPING DRY AND SEASONABLE CONDITIONS FOR THE AREA THROUGH THURSDAY. WITH HIGH PRESSURE IN CONTROL THROUGH MUCH OF THE PERIOD...REMAINED CLOSE TO GUIDANCE TEMPS DURING THE PERIOD. ASIDE FROM MONDAY NIGHT THROUGH TUES NIGHT WITH THE FRONTAL BOUNDARY IN THE AREA...ONLY ISSUE WITH TEMPS WILL BE MINS IN THE EXTENDED WITH POSSIBLE RADIATING CONDITIONS ALLOWING RURAL LOCATIONS TO BE COOLER THAN FORECAST ESP FOR WED NIGHT. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... FOG WILL BURN OFF OVER NEXT HOUR OR TWO. CONVECTION IS EXPECTED TO DEVELOP MAINLY EAST THIS AFTERNOON AS SHORTWAVE DROPS SOUTHEAST ACROSS THE REGION. SOME WIDELY SCATTERED STUFF POSSIBLE ELSEWHERE IN THE FORECAST AREA THROUGH THE AFTERNOON. GENERALLY VFR CONDITIONS EXPECTED AFTER 00Z THIS EVENING. OUTLOOK...MAINLY VFR CONDITIONS EXPECTED SATURDAY AND SUNDAY. NEXT FRONT WILL LIKELY HOLD OFF UNTIL LATE MONDAY OR TUESDAY FOR THE NEXT POSSIBLE THREAT OF PRECIP. && .MARINE... N TO NW FLOW MAY BE CLOSE TO SMALL CRAFT CONDITIONS AT TIMES TONIGHT AND SATURDAY BUT THINK 10 TO 20 KNOTS AND 2 TO 4 FOOT WAVES SHOULD BE THE TOP END. A SW FLOW AHEAD OF A WEAK COLD FRONT DUE OVER THE LAKE ABOUT MONDAY NIGHT MAY PICK UP TO 15 TO 20 KNOTS SOMETIME LATER SUNDAY INTO MONDAY AND PRODUCE 23 TO 5 FOOT WAVES BUT THE WINDS DIRECTIONS SHOULD KEEP THESE HIGHER WAVES IN THE OFFSHORE WATERS. THE PASSAGE OF THE FRONT MONDAY NIGHT SHOULD VEER THE SW WINDS TO A N THEN NE TO E DIRECTION TUE INTO WED. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...TK NEAR TERM...TK SHORT TERM...TK LONG TERM...ABE AVIATION...ABE MARINE...ADAMS oh AREA FORECAST DISCUSSION...CORRECTED NEAR TERM NATIONAL WEATHER SERVICE STATE COLLEGE PA 1133 AM EDT FRI AUG 15 2008 .SYNOPSIS... A WELL-DEFINED MID LEVEL CIRCULATION...CONTAINED WITHIN AN UNSEASONABLY STRONG UPPER LEVEL TROUGH OVER MUCH OF THE EASTERN U.S...WILL MOVE EAST NORTHEAST OF THE LOWER GREAT LAKES REGION TODAY. A RELATIVELY SHARP CYCLONIC FLOW WILL LINGER OVER CENTRAL PENNSYLVANIA THROUGH THE WEEKEND. HIGH PRESSURE AT THE SURFACE AND ALOFT IS FORECAST TO MOVE INTO THE AREA BY MID-WEEK BRINGING A SEVERAL DAY PERIOD OF WARM AND MAINLY DRY WEATHER. && .NEAR TERM /UNTIL 8 PM THIS EVENING/... AT 15Z...SFC ANALYSIS SHOWED AN ILL DEFINED SFC TROUGH EXTENDING FROM NEAR THE SOUTHERN NEW ENGLAND COAST...WEST ACROSS THE MID SUSQ VALLEY TO THE LAUREL HIGHLANDS OF SWRN PENN. HIGHER DEWPOINTS IN THE LOWER 60S WILL BE FOUND SOUTH OF THE BOUNDARY...WITH MID TO UPPER 50S ACROSS MUCH OF CENTRAL AND NRN PENN THIS AFTERNOON. A RATHER EXTENSIVE MID CLOUD DECK (FORMED FROM WEAK ISENTROPIC LIFT ALONG THE 305-310K THETA SFCS) WILL GRADUALLY DISSOLVE/SLIDE EAST THIS AFTERNOON...ALLOWING FOR BETTER SFC HEATING AND MIXED LAYER CAPES TO RAMP UP TO 700-1000 J/KG. IN MOST LOCATIONS...THIS WILL BE SLIGHTLY LESS CAPE THAN THAT WHICH AIDED IN THE PEA TO 1/2 INCH HAIL PRODUCING PULSE STORMS WE HAD THURSDAY AFTN/EARLY EVENING. THE FEW EXCEPTIONS COULD BE NEAR SE BOUNDARY OF THE LAKE ERIE BREEZE ACROSS WARREN CTY (WHERE THE BEST 700-500 HPA COLD ADVECTION WILL BE OCCURRING)...AND ALSO OVER SCHUYLKILL COUNTY...SW INTO THE LWR SUSQ VALLEY (WHICH WILL FEEL THE COMBINED EFFECTS OF BEING CLOSER TO...THE FAVORABLE RIGHT ENTRANCE OF AN UPPER JET MAX AND THE AFOREMENTIONED SFC FRONT...AND WITHIN THE AREA OF GREATER LLVL MOISTURE). SPC DAY 1 SLGT RISK OUTLOOK JUST CLIPS THE FAR ERN PORTION OF THE LWR SUSQ VLY...WHICH IS LOCATED CLOSEST TO THE ENT REGION OF THE AFOREMENTIONED JET MAX. PARCEL EQUILIBRIUM LEVELS FROM KIPT...SOUTH TO KMDT NOSE ONLY ABOUT 3KFT ABOVE THE -20C LEVEL...SO AGAIN I EXPECT THE THREAT FOR 1/2 - 3/4 INCH HAIL TO BE LESS THAN YESTERDAY. WEAK LOW TO MID LEVEL WINDS WILL MAKE FOR A MINIMAL WIND GUST THREAT...BUT ANY STRONG ELEVATED REFLECTIVITY CORES COULD DROP QUICKLY TO THE SFC THROUGH THE UPDRAFTS AND PRODUCE A BRIEF MICROBURST GUST TO 40 OR 50 MPH. && .SHORT TERM /8 PM THIS EVENING THROUGH 6 PM SATURDAY/... ANY LINGERING SHRA/TSRA SHOULD WEAKEN AND SLIDE EWD TWD THE MID- ATLC COAST OVERNIGHT AS THE SHORT WAVE TROF MOVES EWD THRU INTERIOR NEW ENGLAND. HELD ONTO SOME SLGT CHC POPS ACROSS THE FAR ERN ZONES FOR LATE TNT...BUT MOST LOCATIONS SHOULD BEGIN TO DRY/CLEAR OUT SOME AFT MIDNIGHT. AREAS OF FOG WILL LIKELY DEVELOP AGAIN - ESP WHERE IT RAINS TDY. HAVE ADDED IN SOME SLGT CHC POPS FOR SAT AS THE UPPER TROF AXIS SWINGS EAST THROUGH THE REGION. ALTHOUGH THE MODELS SHOW LITTLE TO NO PCPN ACCOMPANYING THIS FEATURE...FEEL SOME SMALL POPS ARE WARRANTED GIVEN THE THREAT FOR INSTABILITY SHRA/TSRA. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... GRADUAL CLEARING WILL OCCUR AFTER MIDNIGHT SAT NIGHT...SETTING THE STAGE FOR A MAINLY SUNNY...WARM AND DRY SUNDAY AND MONDAY AS A RATHER LARGE SFC HIGH SLIDES EAST FROM THE OHIO VALLEY...AND REACHES THE VIRGINIA COAST MONDAY AFTERNOON. FOR TUESDAY THROUGH AT LEAST THURSDAY...NEAR TO ABOVE NORMAL 500 HPA HEIGHTS AND 850 HPA TEMPS WILL YIELD MAX TEMPS 2 TO 4 DEG IN MOST AREAS...WITH OVERNIGHT LOWS WITHIN A FEW DEG EITHER SIDE OF NORMAL. LOCATIONS THROUGHOUT THE MID AND LOWER SUSQ VALLEY SHOULD SEE MAX TEMPS IN 85 TO 90F RANGE FOR MONDAY THROUGH WEDNESDAY BEFORE CLOUDS INCREASE AS PWATS RISE TO 1-2 ST DEVIATIONS ABOVE NORMAL. ELSEWHERE...HIGH TEMPS WILL RANGE FROM THE U70S ACROSS THE NRN AND WRN MTNS...TO THE L80S ACROSS THE CENTRAL MTNS. GEFS SHOWS A WEAK SFC FRONT SAGGING SOUTH ACROSS THE REGION TUESDAY AND WEDNESDAY. THIS COULD TRIGGER A FEW SHRA/TSRA BOTH AFTERNOONS...BEFORE THE BOUNDARY WASHES OUT ACROSS THE MID ATLANTIC REGION. THE ILL DEFINED FRONT WILL DRIFT BACK TO THE NORTH AS A WARM FRONT/OR MEANDER ACROSS OUR REGION LATER IN THE WEEK. WILL KEEP MENTION OF SCATTERED...MAINLY AFTERNOON/EVENING SHOWERS AND TSRA IN THE FCST FOR THE LATE WEEK PERIOD. MREF PLUMES ARE BASICALLY DRY FOR SUNDAY AND MONDAY...BEFORE RAMPING UP DURING THE MID TO LATE WEEK PERIOD. MEAN...MREF TOTAL QPF FOR THE SECOND HALF OF NEXT WEEK IS AROUND 1.5 INCHES FOR MANY LOCATIONS...WHICH TAKES INTO ACCOUNT SEVERAL ROUNDS OF CONVECTION. && .AVIATION /15Z FRIDAY THROUGH TUESDAY/... LATEST RUC13 RH SUGGESTS EARLY LOW CLDS/FOG SHOULD LIFT BY ARND 14Z...THEN SCT DIURNAL SHWRS/TSTMS EXPECTED TO DEVELOP DURING THE AFTN AS UPPER TROF SHIFTS EAST ACROSS THE REGION. BRIEF VSBY/CIG REDUCTIONS POSSIBLE FROM THESE STORMS...MAINLY EASTERN/CENTRAL PA. HOWEVER...VFR CONDS AND LIGHT WINDS EXPECTED TO PREDOMINATE. HIGH PRES IS FCST TO MOVE INTO PA THIS WEEKEND AND EARLY NEXT WEEK...PROVIDING GENERALLY GOOD FLYING CONDS WITH LIGHT WINDS AND A LOW CHC OF PRECIP. A DYING COLD FRONT COULD PRODUCE A FEW LATE DAY TSTMS OVER NORTHERN PA SUN/MON. THAT BOUNDARY COULD DRIFT FURTHER SOUTH BY TUES...BRINGING THE CHC OF AFTN TSTMS TO SOUTHERN PA. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...LAMBERT SHORT TERM...LAMBERT/STEINBUGL LONG TERM...LAMBERT AVIATION...FITZGERALD pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 207 AM EDT FRI AUG 15 2008 .SYNOPSIS... AN UPPER LEVEL TROUGH EXTENDING FROM EASTERN CANADA TO THE GREAT LAKES REGION WILL MOVE SLOWLY SOUTHEAST TONIGHT AND BECOME LOCATED ACROSS PENNSYLVANIA AND NEW YORK STATE EARLY SATURDAY. THIS WEATHER FEATURE WILL LIFT TO THE NORTHEAST ACROSS NEW ENGLAND DURING THE SECOND HALF OF THE WEEKEND. MOST OF THE WEEKEND SEEMS TO BE DRY AS HIGH PRESSURE SLIDES IN FROM THE MIDWEST. IT COULD GET HOT FOR THE MIDDLE OF NEXT WEEK...AS HIGH PRESSURE SETS UP OFF THE EAST COAST AND LOW PRESSURE RESIDES OVER THE GREAT PLAINS. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... A FEW MORE HOURS OF SHOWERS ACROSS THE EAST...THEN ISOLATED SHOWERS POSSIBLE OVERNIGHT...MAINLY NW...AS NEW ACTIVITY DRIFTS SE. SOME PATCHY FOG. FRIDAY WILL BE SIMILAR TO THU...WITH THE UPPER LEVEL TROUGH. PERHAPS LESS ACTIVE...EXCEPT FOR THE SE. SEE BELOW FOR MORE DETAIL. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/... LITTLE CHANGE TO PREVIOUS THINKING HERE. SCATTERED SHRA/TSRA WILL BECOME ISOLATED AFTER 06Z. PATCHY FOG LIKELY ONCE AGAIN EARLY FRIDAY MORNING UNDER PARTIAL CLEARING...SIMILAR LLVL MOISTURE...AND NEAR CALM SFC WIND. FRIDAY LOOKS LIKE A NEAR REPEAT OF TODAY WITH VERY SIMILAR AMBIENT CONDITIONS...BEGINNING WITH SOME THICK LOW LEVEL STRATUS AND LIKELY SOME AREAS OF DENSE FOG BEFORE 14Z. THE UPPER LOW WILL BE CLOSER TO THE LOCAL AREA...PERHAPS OVER WRN NY. THIS WILL HELP A FEW STORMS PRODUCE SOME LARGER HAIL...AND A JET STREAK THAT SHOULD BE OFF TO OUR SOUTH MAY ENHANCE THE DEEP- LAYER SHEAR. SO ISOLATED SEVERE STORMS ARE POSSIBLE AGAIN AND SPC HAS US INCLUDED IN THEIR SEE TEXT AREA FOR LCLY SVR PULSE STORMS. MAX TEMPS WILL REMAIN SLIGHTLY BELOW NORMAL. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... UPPER TROUGH AXIS PUSHES EAST ACROSS THE CWA DURING THE DAY SATURDAY WITH THE STEEPEST MID LEVEL LAPSE RATES AND MIXED LAYER CAPE OF UP TO SEVERAL HUNDRED J/KG PUSHING EAST OF THE SUSQ VALLEY BY 00Z SUNDAY. WENT WITH CHC POPS FOR AFTERNOON SHRA...WITH ISOLATED TSRA POSSIBLE ACROSS THE MIDDLE SUSQ VALLEY AND NORTH CENTRAL MTNS. 700 HPA TEMPS IN THAT AREA WILL DIP TO SLIGHTLY BELOW ZERO BETWEEN 18Z SAT AND 00Z SUNDAY. GRADUAL CLEARING WILL OCCUR AFTER MIDNIGHT SAT NIGHT...SETTING THE STAGE FOR A MAINLY SUNNY...WARM AND DRY SUNDAY AND MONDAY AS A RATHER LARGE SFC HIGH SLIDES EAST FROM THE OHIO VALLEY...AND REACHES THE VIRGINIA COAST MONDAY AFTERNOON. FOR TUESDAY THROUGH AT LEAST THURSDAY...NEAR TO ABOVE NORMAL 500 HPA HEIGHTS AND 850 HPA TEMPS WILL YIELD MAX TEMPS 2 TO 4 DEG IN MOST AREAS...WITH OVERNIGHT LOWS WITHIN A FEW DEG EITHER SIDE OF NORMAL. LOCATIONS THROUGHOUT THE MID AND LOWER SUSQ VALLEY SHOULD SEE MAX TEMPS IN 85 TO 90F RANGE FOR MONDAY THROUGH WEDNESDAY BEFORE CLOUDS INCREASE AS PWATS RISE TO 1-2 ST DEVIATIONS ABOVE NORMAL. ELSEWHERE...HIGH TEMPS WILL RANGE FROM THE U70S ACROSS THE NRN AND WRN MTNS...TO THE L80S ACROSS THE CENTRAL MTNS. GEFS SHOWS A WEAK SFC FRONT SAGGING SOUTH ACROSS THE REGION TUESDAY AND WEDNESDAY. THIS COULD TRIGGER A FEW SHRA/TSRA BOTH AFTERNOONS...BEFORE THE BOUNDARY WASHES OUT ACROSS THE MID ATLANTIC REGION. THE ILL DEFINED FRONT WILL DRIFT BACK TO THE NORTH AS A WARM FRONT/OR MEANDER ACROSS OUR REGION LATER IN THE WEEK. WILL KEEP MENTION OF SCATTERED...MAINLY AFTERNOON/EVENING SHOWERS AND TSRA IN THE FCST FOR THE LATE WEEK PERIOD. MREF PLUMES ARE BASICALLY DRY FOR SUNDAY AND MONDAY...BEFORE RAMPING UP DURING THE MID TO LATE WEEK PERIOD. MEAN...MREF TOTAL QPF FOR THE SECOND HALF OF NEXT WEEK IS AROUND 1.5 INCHES FOR MANY LOCATIONS...WHICH TAKES INTO ACCOUNT SEVERAL ROUNDS OF CONVECTION. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... EARLY MORNING WATER VAPOR IMAGERY SHOWING UPPER LOW CENTERED OVER S ONTARIO. ASSOCIATED DIURNAL SHWR/TSTM ACTIVITY HAS LARGELY DISSIPATED FOR THE NIGHT. HOWEVER...BAND OF MID LVL CLOUDINESS AHEAD OF UPPER LOW WILL BE CRITICAL IN DETERMINING IF DENSE FOG FORMS. LATEST RUC13 RH DATA SUGGESTS THE CENTRAL PART OF THE STATE FROM JST NE TO IPT WILL REMAIN MCLDY...WHICH WILL KEEP TEMPS UP AND FOG TO A MINIMUM. MEANWHILE...NORTHWEST PA /BFD/ AND SOUTHEAST PA /MDT/ APPEAR LIKELY TO REMAIN MCLEAR FOR THE NEXT SEVERAL HRS...RESULTING IN THE POSSIBILITY OF LOCALLY DENSE RADIATION FOG. HAVE THUS...GONE A BIT MORE PESSIMISTIC THAN MOS AT THESE LOCATIONS THIS AM. ANY FOG SHOULD LIFT BY ARND 14Z...THEN SCT DIURNAL SHWRS/TSTMS EXPECTED TO ERUPT DURING THE AFTN AS UPPER TROF SHIFTS EAST ACROSS THE REGION. BRIEF VSBY/CIG REDUCTIONS POSSIBLE FROM THESE STORMS...MAINLY EASTERN/CENTRAL PA. HOWEVER...VFR CONDS LIGHT WINDS EXPECTED TO PREDOMINATE. HIGH PRES IS FCST TO MOVE INTO PA THIS WEEKEND AND EARLY NEXT WEEK...PROVIDING GENERALLY GOOD FLYING CONDS WITH LIGHT WINDS AND A LOW CHC OF PRECIP. A DYING COLD FRONT COULD PRODUCE A FEW LATE DAY TSTMS OVER NORTHERN PA SUN/MON. THAT BOUNDARY COULD DRIFT FURTHER SOUTH BY TUES...BRINGING THE CHC OF AFTN TSTMS TO SOUTHERN PA. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DEVOIR/LAMBERT NEAR TERM...DEVOIR/LAMBERT/MARTIN/RXR SHORT TERM...DEVOIR LONG TERM...LAMBERT AVIATION...FITZGERALD pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 249 AM EDT FRI AUG 15 2008 .SYNOPSIS... A TROUGH OF LOW PRESSURE WILL CROSS THE AREA FROM THE NORTH LATE FRIDAY. HIGH PRESSURE THEN BUILDS IN FROM THE WEST ON SATURDAY...AND REMAINS OVER THE REGION INTO THE MIDDLE OF NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A TROUGH OVER THE EASTERN CONUS WILL SHARPEN A LITTLE TODAY...WITH AN EMBEDDED SHORTWAVE...NOW OVER MO...EXPECTED TO CROSS INTO THE MOUNTAINS LATER IN THE DAY. AN ASSOCIATED SFC FRONT WILL BECOME A LITTLE MORE DEFINED AS WELL. GOOD CONVERGENCE WILL DEVELOP OVER THE NC FOOTHILLS AND PIEDMONT AHEAD OF THE FRONT. THE NAM POOLS LLVL DEWPOINTS IN THIS AREA AND DEVELOPS QUITE A BIT OF CONVECTIVE PCPN AS A RESULT...ESPECIALLY OVER THE SRN NC PIEDMONT. THE GFS ISN/T TOO DISSIMILAR...THOUGH THE FEATURES ARE WEAKER AND THE TIMING SLOWER. THE NAM LOOKS LIKE A REASONABLE SOLUTION AT THIS POINT...AND I/LL CARRY MY HIGHEST POPS...ALBEIT ONLY AROUND 40 PERCENT...OVER THE I-77 CORRIDOR. IF THE NAM TURNED OUT TO BE A PERFECT PROG...THEN LIKELY POPS WOULD BE NEEDED IN THIS AREA. HOWEVER...OWING TO THE WEAK SYNOPTIC SCALE FORCING...I/M NOT CONFIDENT ENUF TO GO WITH MORE COVERAGE THAN SCT. GFS AND NAM MIX OUT DEWPOINTS OVER THE UPSTATE AND NC MOUNTAINS THIS AFTERNOON. I THINK WE WILL SEE SOME ACTIVITY IN BOTH LOCATIONS...BUT IT WILL BE MORE ISOLATED IN NATURE. THERE WILL BE A SEVERE THREAT THIS AFTERNOON AND EVENING. BULK SHEAR WILL BE ON THE ORDER OF 20 TO 25 KTS AND FREEZING LEVELS WILL REMAIN HIGH. TEMP/DEWPOINT DEPRESSIONS WON/T BE UNUSUALLY LARGE...SO THE THREAT WILL BE FOR ISOLATED AREAS OF DAMAGING WIND AND HAIL GENERALLY UNDER AN INCH IN DIAMETER IN PULSE STORMS AND A FEW MULTICELL CLUSTERS. ACTIVITY MAY LINGER UNTIL MIDNIGHT IN THE AXIS OF LLVL CONVERGENCE. THEREAFTER THE SFC FRONT SHOULD MOVE SOUTHEAST OF THE REGION...BRINGING IN DRIER AIR. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/... AS OF 230 AM FRIDAY...UPR LVL ERN CONUS TROF WILL PROGRESS ACRS THE APPALACHIAN MTNS SATURDAY AFTN...WITH AN ASSOC SFC TROF. MODEL SOUNDINGS INDICATE VERY LMTD MOISTURE WITH THE TROF PASSAGE. LATEST GUIDANCE STILL SEEMS TO JUSTIFY ONLY A SLGT CHC POP FOR THE AFTN...SO ONLY MADE MINOR TWEAKS. TEMPS LOOK TO BE A DEG OR TWO BLO NORMAL (70S TO LWR 80S MTNS AND MID TO UPR 80S PIEDMONT). SATURDAY NIGHT THRU SUNDAY NIGHT...SFC HI PRES BLD IN FROM THE NW...KEEPING THINGS DRY AND SLIGHTLY BLO NORMAL TEMPS. MOISTURE AND LOW LVL CONVERGENCE LOOK TO STAY S OF THE CWFA THRU LATE SUNDAY. ALTHOUGH THE 00Z/15 GFS TRIES TO GENERATE SOME QPF ALONG A WK CONVERGENCE ZONE IN THE UPR SAVANNAH VLY...CONFIDENCE IS LOW ENUF TO KEEP IT OUT OF THE FCST. && .LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 230 AM FRIDAY...THE LATEST GUIDANCE ALL SEEM TO BE COMING IN WITH A STRONGER UPR RIDGE ACRS THE EASTERN CONUS...HELPING TO PREVENT A TROPICAL FEATURE FROM RECURVING E OF FL. BOTH THE 12Z/14 ECMWF AND 00Z/15 GFS HAVE THE SYSTEM TURN TWD THE W...CROSSING THE FL PENINSULA AND INTO THE GULF OF MEXICO. IF THIS VERIFIES...OUR AREA MAY BE QUITE DRY THRU THURSDAY UNDER DEEP SUBSIDENCE. SINCE BASICALLY ALL THE LATEST GUIDANCE IS DRIER THAN INHERITED GRIDS...I BLENDED IN THE 00Z/15 MEX FOR POPS AND TEMPS...RESULTING IN NOTHING HIER THAN SLGT CHC POP FROM MONDAY NIGHT THRU FRIDAY. SINCE THE EXTENDED FCST IS HIGHLY DEPENDENT ON TRENDS IN THE AFOREMENTIONED TROPICAL SYSTEM...OVERALL CONFIDENCE IS RATHER LOW. && .AVIATION /07Z FRIDAY THROUGH TUESDAY/... LINGERING SHOWERS JUST SOUTH OF KCLT SHOULD DISSIPATE BEFORE LONG AND WILL HAVE NO EFFECT ON THE AIRFIELD. MOS GUIDANCE IMPLIES THAT MVFR FOG WILL FORM AT MOST SITES DURING THE EARLY MORNING HOURS. THE LLVL FLOW IS VERY LIGHT...WHICH SHOULD LIMIT STRATUS POTENTIAL. ALSO...THE RUC CIG HEIGHTS DON/T SHOW ANY LOW CLOUDS OVER THE REGION THIS MORNING...AND IT TYPICALLY OVERDOES STRATUS. I HAVE FOG DEVELOPING AT ALL AIRFIELDS...WITH KAVL GOING DOWN FOR SEVERAL HOURS IN LIFR FOG AS WINDS WILL BE LIGHT AND SKIES MOSTLY CLEAR THE REST OF THE NIGHT. WINDS WILL BE LIGHT OVERNIGHT...AND GENERALLY OUT OF THE SOUTHWEST AFTER SUNRISE. LATE IN THE DAY A COLD FRONT WILL DROP SOUTH ACROSS THE REGION...TURNING THE WINDS OUT OF THE NORTH NORTHEAST DURING THE EARLY EVENING. SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG AND AHEAD OF THE FRONT...BUT WITH LIMITED COVERAGE I ONLY INCLUDED A CB GROUP IN THE TAFS ATTM. CHANCES WL BE BEST OVER TOWARD KCLT WHERE THE GREATEST INSTABILITY WILL BE FOUND LATER IN THE DAY. OUTLOOK...DRY CONDITIONS ARE EXPECTED BEHIND A COLD FRONT SATURDAY AND SUNDAY. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED MONDAY AND TUESDAY...AND SOME MORNING RESTRICTS IN FOG ARE POSSIBLE...ESPECIALLY AT FOG PRONE AIRFIELDS. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...ARK NEAR TERM...MCAVOY SHORT TERM...ARK LONG TERM...ARK AVIATION...MCAVOY sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 154 AM EDT FRI AUG 15 2008 .SYNOPSIS... A WEAK SURFACE TROUGH WILL MOVE ACROSS THE AREA FROM THE NORTH LATE FRIDAY. WEAK HIGH PRESSURE MOVES IN FROM THE WEST ON SATURDAY BUT WILL BE PUSHED OUT EARLY NEXT WEEK WITH THE APPROACH OF ANOTHER FRONTAL BOUNDARY ON WEDNESDAY. && .NEAR TERM /THROUGH TODAY/... SCT CONVECTION LINGERING OVER E CWA SO BUMPED UP POPS THRU 2 AM... THEN EXPECT CONVECTION TO DIMINISH AS WEAK SHORTWAVE MOVES E AND WITH CONTINUED COOLING. BEST CHANCE OF FOG IS ACROSS THE MOUNTAIN VALLEYS AND AREAS THAT GOT RAIN THIS AFTN-EVE BUT CLOUDS WILL LINGER OVER E CWA LONGER TONIGHT. COMPROMISED WITH MENTION OF PATCHY FOG ACROSS CWA. ALSO TWEAKED HOURLY TEMP/DP/RH THIS UPDATE. ADDITIONAL H5 SHORTWAVES WILL CROSS THE FORECAST AREA FROM THE WEST FRIDAY AFTERNOON TO PRODUCE ISOLATED CONVECTION...WITH SCATTERED COVERAGE IN THE HIGH TERRAIN. NORHTWESTERLY 850 MB FLOW SHOULD CREATE MORE CONVERGENCE ALONG A LEE TROUGH OUT INTO THE PIEDMONT FOR FRIDAY AFTN AS WELL. 850 MB TEMPS LOOK TO REBOUND A COUPLE OF DEGREES FRIDAY AFTN OVER TODAY TO YIELD WARMER MAX TEMPS. && .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... AS OF 230 PM THURSDAY...SHORT RANGE MODELS AGREE THAT THE AXIS OF A H5 L/W WILL MOVE ACROSS THE CWA SATURDAY AFTERNOON AND EARLY EVENING. FORECAST SOUNDINGS INDICATE THAT THE MOISTURE CONTENT OF THE LOW AND MID LEVELS IS FAIRLY LOW. IN ADDITION...AN INVERSION BETWEEN H5-H6 MAY KEEP THE SFC BASED PARCELS CAPPED. HOWEVER...THE PASSAGE OF THE MID LEVEL TROF MAY RESULT IN A ELONGATED LEE TROF ALONG AND EAST OF I-85 SAT AFTERNOON. I WILL PAINT THE REGION EAST OF THE MTNS WITH A AFTERNOON SCHC OF SHRA AND TSRA. USING A BLEND OF MOS...TEMPERATURES SHOULD RANGE FROM THE L80S IN THE MTN VALLEYS TO U80S EAST. SUNDAY AND SUNDAY NIGHT...TROF AXIS WILL CONTINUE TO SHIFT EAST RESULTING IN DRY NORTH TO NORTHWEST FLOW. FORECAST SOUNDINGS SHOW THE PW DROPPING TO .8 INCHES SUNDAY AFTERNOON WITH A STRONG MID LEVEL INVERSION. I WILL KEEP THE FORECAST DRY SENSIBLE WEATHER WITH PARTLY TO MOSTLY CLEAR CONDITIONS. TEMPERATURES SHOULD REMAIN SLIGHTLY ABOVE NORMAL. MONDAY AND TUESDAY...USING A BLEND OF THE GFS AND ECMWF...DEEPER MOISTURE WILL REMAIN EAST OF THE FORECAST AREA. MOISTURE WILL SLOW DRIFT NORTHWARD ON TUESDAY...POSSIBLY ASSOCIATED WITH A TROPICAL FEATURE. AT THIS POINT...IT APPEARS THAT ISOLATED TO SCATTERED SHRA AND TSRA WILL DEVELOP EACH AFTERNOON AND EVENING. MOS GUIDANCE AND HPC VALUES SUPPORT TEMPERATURES SEVERAL DEGREE ABOVE NORMAL. && .LONG TERM /TUESDAY THROUGH THURSDAY/... AS OF 2 PM THURSDAY...THE PERIOD OF 00Z WEDNESDAY THROUGH THE END OF THE DAY FRIDAY APPEARS TO BE RATHER TYPICAL FOR SUMMERTIME. AGAIN...THE HPC PREFERRED MODEL WAS THE ECMWF. AS FOR THE LOCAL FORECAST AREA...A BLEND OF HPC GUIDANCE AND GMOS WERE USED TO ACHIEVE A DECENT ENOUGH BLEND TO MATCH THE OVERALL PICTURE OF THE EXTENDED RANGE. A WEAK FRONT WILL APPROACH THE FORECAST AREA FROM THE NORTHEAST AND STALL ACROSS THE EASTERN PIEDMONT OF NORTH CAROLINA THROUGH THURSDAY. THIS FRONT COMBINED WITH SUFFICIENT MOISTURE SHOULD BE ENOUGH TO SPARK A FEW DIURNALLY DRIVEN THUNDERSTORMS ACROSS THE AREA THROUGHOUT THE PERIOD. DAYTIME MAXIMUMS AND MINIMUMS SHOULD CONTINUE TO BE AROUND OR SLIGHTLY ABOVE NORMAL FOR THIS TIME OF YEAR. FRIDAYS FORECAST WAS DIFFICULT WITH THE POSSIBILITY OF THE TROPICAL SYSTEM APPROACHING THE SOUTHEASTERN UNITED STATES BY LATE NEXT WEEK. THE IMPACT OF THIS STORM ON THE CWA IS STILL VERY UNCLEAR...BUT SHOULD PROVE TO BE AN INTERESTING FEATURE TO WATCH OVER THE NEXT SEVERAL DAYS. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... LINGERING SHOWERS JUST SOUTH OF KCLT SHOULD DISSIPATE BEFORE LONG AND WILL HAVE NO AFFECT ON THE AIRFIELD. MOS GUIDANCE IMPLIES THAT MVFR FOG WILL FORM AT MOST SITES DURING THE EARLY MORNING HOURS. THE LLVL FLOW IS VERY LIGHT...WHICH SHOULD LIMIT STRATUS POTENTIAL. ALSO...THE RUC CIG HEIGHTS DON/T SHOW ANY LOW CLOUDS OVER THE REGION THIS MORNING...AND IT TYPICALLY OVERDOES STRATUS. I HAVE FOG DEVELOPING AT ALL AIRFIELDS...WITH KAVL GOING DOWN FOR SEVERAL HOURS IN LIFR FOG AS WINDS WILL BE LIGHT AND SKIES MOSTLY CLEAR THE REST OF THE NIGHT. WINDS WILL BE LIGHT OVERNIGHT...AND GENERALLY OUT OF THE SOUTHWEST AFTER SUNRISE. LATE IN THE DAY A COLD FRONT WILL DROP SOUTH ACROSS THE REGION...TURNING THE WINDS OUT OF THE NORTH NORTHEAST DURING THE EARLY EVENING. SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG AND AHEAD OF THE FRONT...BUT WITH LIMITED COVERAGE I ONLY INCLUDED A CB GROUP IN THE TAFS ATTM. CHANCES WL BE BEST OVER TOWARD KCLT WHERE THE GREATEST INSTABILITY WILL BE FOUND LATER IN THE DAY. OUTLOOK...DRY CONDITIONS ARE EXPECTED BEHIND A COLD FRONT SATURDAY AND SUNDAY. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED MONDAY AND TUESDAY...AND SOME MORNING RESTRICTS IN FOG ARE POSSIBLE...ESPECIALLY AT FOG PRONE AIRFIELDS. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS... NEAR TERM...HG/RB SHORT TERM...NED LONG TERM... AVIATION...MCAVOY sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 843 PM CDT SAT AUG 16 2008 .DISCUSSION...SATELLITE AND RADAR IMAGES INDICATE CONVECTION HAS DIMINISHED ACROSS THE CWA THIS EVENING. KBRO 88D ESTIMATED SEVERAL INCHES OF RAINFALL FELL ACROSS SOUTHEAST PORTIONS OF HIDALGO COUNTY DURING THE LATE AFTERNOON HOURS. RUC80 500MB HEIGHT ANALYSIS INDICATED A WEAK LOW ACROSS SOUTH TEXAS. IN ADDITION...MSAS SURFACE ANALYSIS INDICATED A WEAK FRONTAL BOUNDARY ACROSS PORTIONS OF SOUTH TX. THE COMBINATION OF THESE TWO FEATURES CONTINUES TO PROVIDE SHOWERS AND ISOLATED THUNDERSTORMS ACROSS SOUTH CENTRAL TX AND THE HILL COUNTRY EXTENDING INTO PORTIONS OF THE RIO GRANDE PLAINS. THIS CONVECTION SHOULD ALSO DIMINISH WITH THE LOSS OF DIURNAL HEATING. WILL LOWER POPS TONIGHT AND DECREASE CLOUD COVER SLIGHTLY AS A RESULT. PRECIPITABLE WATER VALUES REMAIN ABOVE TWO INCHES ACROSS THE LOWER RIO GRANDE VALLEY SO ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS IS POSSIBLE SUN AFTERNOON MAINLY ALONG THE SEABREEZE. && .AVIATION...VFR CONDITIONS WILL RETURN THIS EVENING AFTER ANOTHER ROUND OF SEA BREEZE CONVECTION TODAY. MOISTURE REMAINS ELEVATED AND MORE SHOWERS AND THUNDERSTORMS MAY DEVELOP SUNDAY AFTERNOON. THE ACTIVITY WILL LIKELY START IN COASTAL AREAS AND MOVE SOUTH AND WEST TOWARD THE REGIONAL AIRPORTS LATER IN THE AFTERNOON. HARLINGEN AND MCALLEN WILL TEND TO BE MORE IN THE PATH OF THIS ACTIVITY...WHILE THE CONVECTION MAY BYPASS BROWNSVILLE BEFORE BECOMING MUCH OF A THREAT. DEEP THUNDERSTORMS WILL DEVELOP WITH PLENTY OF RAIN AND LIGHTNING...AND MAYBE SOME SMALL EMBEDDED HAIL. GUST SURFACE WINDS TO 40 OR 50 MPH WILL BE POSSIBLE. THE STORMS OF THE PAST FEW DAYS HAVE NOT QUITE REACHED SEVERE STRENGTH...HOWEVER. MVFR CONDITIONS WILL OCCUR NEAR ANY STORMS...WITH POSSIBLE IFR CONDITIONS IN ANY HEAVY DOWNPOURS. && .MARINE...AT 6 PM BUOY 020 REPORTED LIGHT EAST WINDS AND SEAS AT 3 TO 4 FEET WITH A 6 SECOND PERIOD. LIGHT TO MODERATE ONSHORE WINDS WITH SEAS OF 2 TO 4 FEET WILL CONTINUE THROUGH THE FORECAST AS HIGH PRESSURE PERSISTS OVER THE NORTHWEST GULF OF MEXICO. SHOWERS AND ISOLATED THUNDERSTORMS MAY MOVE ACROSS PORTIONS OF THE MARINE AREAS THROUGH THE MIDDLE OF NEXT WEEK. WINDS AND SEAS MAY BE HIGHER IN OR NEAR ANY SHOWERS OR THUNDERSTORMS. && .PREV DISCUSSION... /ISSUED 145 PM CDT SAT AUG 16 2008/ BRO SOUNDING THIS MORNING SHOWED A PRECIP WATER OF 2.05 AND A K-INDEX OF 17. DEEP MOISTURE COULD GIVE DEEP SOUTH TEXAS A GOOD CHANCE FOR SCATTERED SHOWERS OR THUNDERSTORMS DURING THE DAYTIME HOURS THROUGH THE WEEKEND. HIGH PRESSURE BOTH SURFACE AND ALOFT WILL DOMINATE THE AREA BY THE BEGINNING OF NEXT WEEK CAUSING A RELATIVELY DRY AND STABLE AIRMASS TO DEEP SOUTH TEXAS FROM THE BEGINNING OF NEXT WEEK THROUGH THE END OF NEXT WEEK. WINDS WILL BE LIGHT TO MODERATE FROM THE SOUTHEAST THROUGH THE MIDDLE OF NEXT WEEK. BOUNDARY LAYER RELATIVE HUMIDITIES SHOWED ABOVE 50 PERCENT ALL THE WAY UP TO 500 MB THROUGH SUNDAY THEN DRYING OUT SOME BY SUNDAY NIGHT. MARINE...AT NOON BUOY 20 REPORTED SOUTH SOUTHEAST WINDS AT 8 KNOTS WITH GUSTS TO 10 KNOTS AND SEAS AT 3 FEET WITH A 6 SECOND PERIOD. LIGHT TO MODERATE SOUTHEASTERLY WINDS WITH SEAS IN THE 2 TO 4 FEET RANGE WILL CONTINUE ACROSS THE MARINE AREAS THROUGH MONDAY AS A HIGH PRESSURE RIDGE PERSISTS OVER THE COASTAL WATERS. THERE IS A CHANCE FOR SHOWERS AND ISOLATED THUNDERSTORMS MOVING ACROSS PORTIONS OF THE MARINE AREAS AT TIMES THROUGH THE MIDDLE OF NEXT WEEK. WINDS AND SEAS MAY BE HIGHER IN OR NEAR ANY SHOWERS OR THUNDERSTORMS. AVIATION...VFR CONDITIONS WITH MODERATE TO MODERATE AND GUSTY SOUTHEAST WINDS AND MOSTLY CLOUDY TO PARTLY CLOUDY SKIES ARE BEING REPORTED AT THE REGIONAL AIRPORTS. THERE IS A CHANCE FOR SHOWERS AND ISOLATED THUNDERSTORMS MOVING ACROSS PORTIONS OF THE CWA AT TIMES DURING THE NEXT FEW DAYS. ANY SHOWERS OR THUNDERSTORMS MAY TEMPORARILY REDUCE CEILINGS AND/OR VISIBILITIES TO MVFR CONDITIONS. OTHERWISE VFR CONDITIONS WITH LIGHT TO MODERATE SOUTHEASTERLY WINDS WILL CONTINUE ACROSS THE REGIONAL AIRPORTS DURING THE NEXT 24 HOURS. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 80 92 79 91 / 10 30 10 20 BROWNSVILLE 79 94 78 92 / 10 30 10 20 HARLINGEN 78 95 76 93 / 10 30 10 20 MCALLEN 79 94 78 92 / 10 30 10 20 RIO GRANDE CITY 79 97 76 94 / 10 30 10 20 SOUTH PADRE ISLAND 81 89 79 88 / 10 30 10 20 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WWW.WEATHER.GOV/BROWNSVILLE PUBLIC/GRIDS...61 AVIATION/MARINE...54 MESO/FXC...VEGA tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 332 PM CDT SAT AUG 16 2008 .UPDATE... ONE LAST LOOK AT NEW 16.18Z NAM AND RUC13...SHOWS THAT SOME OF SHRA/TSRA NEAR AND SW OF KDLH WILL WORK INTO I-94 CORRIDOR THIS EVENING. FORECAST WILL INCLUDE ISOLD/SCT RAIN CHANCES THROUGH MIDNIGHT...DESPITE LOOPS OF KDLH RADAR SUGGESTING BULK OF THESE SPOTTY SHRA WILL PASS TO THE NORTH/EAST. && .PREV DISCUSSION... /ISSUED 308 PM CDT SAT AUG 16 2008/ SHORT TERM...THROUGH TUESDAY NIGHT WARMEST STINT OF THIS COOL SUMMER SET TO COME THIS FORECAST CYCLE...AND VERY LOW/PESKY RAIN THREATS THE CONCERN THROUGH THE SHORT TERM. CURRENTLY...EXPANSIVE SFC HIGH PRESSURE ACROSS NEB/IA/KS/MO IN CONTROL WITH CONTINUED PLEASANT WEATHER. GOES WATER VAPOR LOOPS SHOWING SEVERAL FEATURES OF INTEREST...THE FIRST OF WHICH IS A WEAK SHORTWAVE IN WRN ONTARIO...A COMPACT AND STRONG CUTOFF LOW OVER UT/CO...AND A STRONGER SHORTWAVE OVER SASK/ALBERTA. GOES VISIBLE IMAGERY SHOWS LARGE DIURNALLY DRIVEN CUMULUS FIELD OVER ENTIRE CNTL CONUS. DEEP MOISTURE LOCKED UP WAY SOUTH OVER THE SRN CONUS...WITH MODIFIED AREA OF HIGH THETA-E AND SEASONABLE PWATS OVER MN/NRN WI AHEAD OF THE ONTARIO SHORTWAVE. ACCAS/-SHRA ALSO NOTED IN FORCED ASCENT REGION AHEAD OF THIS WAVE IN NERN MN/UPPER MICHIGAN. WESTERLY BREEZES NORTH OF THE SFC HIGH ALLOWING DEWPOINTS AGAIN TO MIX INTO THE LOWER 50S OVER THE FORECAST AREA AS TEMPS IN THE UPPER 70S TO LOWER 80S. RUC ANALYSIS /16.18Z/ SHOWS MASSIVE MIDLEVEL WRN CONUS RIDGE/NERN CONUS TROUGH...WITH STRONG CUTOFF LOW IN CO/UT TUCKED NICELY INTO SERN FLANK OF WRN RIDGE...A QUASI REX-BLOCKING STRUCTURE. THE 16.12Z DETERMINISTIC RUNS OF NAM-WRF/GFS/GEM ALL CONTINUE GENERAL DRY TREND...WITH SOME CAVEATS. IN GENERAL...THE NAM-WRF REMAINS THE MOST EAGER TO DEVELOP QPF...HAS HIGHER INSTABILITY...AND HIGHER PWATS...DUE WHAT SEEMS TO BE AN OVERESTIMATION OF BOUNDARY LAYER MOISTURE. HOWEVER...ITS HIGHER RESOLUTION NEEDS TO BE CONSIDERED HERE...SO THERE IS LOWER THAN NORMAL CONFIDENCE ON THE LOW STORM THREATS OVER MN/WI OVER THE NEXT FEW DAYS. TONIGHT...ONTARIO SHORTWAVE DRIVES SOUTHEAST THROUGH UPPER GREAT LAKES WITH A VERY WEAK/ALMOST NONEXISTENT LOW CONVERGENCE AXIS. RUC13 ALL DAY AS WELL AS NAM-WRF HAS WANTED TO CONVECT ACROSS CNTL MN INTO NERN MN BACK INTO ERN SD...AND THIS YET TO HAPPEN THROUGH 20Z. ANALYSIS OF TAMDARS /MSP/ CONFIRM LOW LEVEL MOISTURE TOO HIGH IN RUC/NAM...THUS LARGER SCALE TRENDS OF GFS/SREF/LOCALLY RUN ARW-WRF OF KEEPING VERY ISOLD-SCT DEVELOPMENT THROUGH THE EVENING HOURS LOOKS GOOD. DO EXPECT THIS ISOLD/SCT CONVECTION TO DEVELOP INTO NRN WISCONSIN THIS EVENING WHERE FORCING FOR ASCENT AND STEEPEST LOW LEVEL LAPSE RATES JUXTAPOSED...AND QUESTION BECOMES WHETHER THIS CAN DRIBBLE INTO NRN/ERN FORECAST AREA OVERNIGHT. GIVEN MORE EVIDENCE OF A RAPID DIMINISHING TREND AFTER SUNSET IN THE MODELS WHICH ARE CAPTURING CURRENT CONVECTIVE TRENDS BETTER...HAVE DECIDED TO KEEP RAIN OUT OF THE NRN/ERN AREAS THIS EVENING. BUT THIS NEEDS TO BE WATCHED CLOSELY. IF SOMETHING MORE ORGANIZED CAN GET GOING OVER NRN WI...STORMS COULD MAINTAIN INTO ERN FORECAST AREA OVERNIGHT. THINK VALLEY FOG LESS WIDESPREAD TONIGHT...AND CONFINED TO WI RIVER VALLEY DUE TO WARMER OVERNIGHT LOWS/MORE BOUNDARY LAYER FLOW ON NORTH SIDE OF HIGH. SUNDAY-TUESDAY...AGAIN...LARGELY A DRY PERIOD HERE WITH VERY WARM TEMPERATURES AS WARM NOSE WRAPPED AROUND CNTL PLAINS HIGH PRESSURE IS ADVECTED IN FROM WEST/NORTHWEST. MAY VERY WELL SEE SOME AREAS AROUND 90F DURING THIS ENTIRE PERIOD...WITH MOISTURE IN THE LOW LEVELS SLOWLY INCREASING. SEVERAL MORE WEAK WAVES IN THE NORTHWEST FLOW WILL SERVE TO DEVELOP/TIGHTEN A SWRD MOVING BAROCLINIC ZONE THROUGH WISCONSIN ON MONDAY AND TUESDAY...WHICH IS THE TAIL END OF A MORE SYNOPTIC SCALE FRONT DROPPING SOUTH AS NERN CONUS TROUGH REDEVELOPS AS THIS ENERGY MOVES INTO THE TROUGH. HERE AGAIN...16.12Z NAM-WRF IS MOST ROBUST WITH CAPE/INSTABILITY/PWATS AND IS MORE EAGER TO DEVELOP SPOTTY/ISOLD STORMS DIURNALLY AS CUMULUS FORMS AND CINH IS SMALL EACH AFTERNOON. WILL PROBABLY HAPPEN...BUT LARGER SCALE RIDGE BUILDING IN BY TUESDAY DOESN/T OFFER MUCH SUPPORT...AND THINK ANY STORM DEVELOPMENT SUN-TUES WILL BE VERY HARD TO PIN DOWN AND GIVEN LACK OF LARGER SCALE FORCING SIGNAL. THIS IS LIKELY WHY COARSE/GLOBAL MODELS SUCH AS GFS/ECMWF/GEM ALL REMAIN MAINLY DRY ASIDE FROM A SPECKLE HERE AND THERE...AND WHY SREF PROBS FOR RAIN ARE SO LOW THROUGH THIS PERIOD. FURTHER INSPECTION OF THE THOSE 16.09Z SREF MEMBERS SHOWING MAINLY KAIN-FRITCH CONVECTIVE SCHEMES ALLOWING THIS SPOTTY ACTIVITY TO DEVELOP. WITH BULK OF EVIDENCE FAVORING A DRY PERIOD...INCLUDING LOCALLY RUN ARW WRF BASED ON GFS...HAVE DECIDED TO WAIT FOR A MORE CONVINCING LARGE SCALE FORCING SIGNAL /SHORTWAVE/ OR SURFACE BOUNDARY...BOTH OF WHICH RIGHT NOW ARE NOT AGREED UPON IN STRENGTH OR LOCATION. BOTTOM LINE...WOULD NOT BE SURPRISED TO SEE SMALL RAIN CHANCES BE ADDED AT SOME POINT IN THE SUN-TUES TIMEFRAME...MAINLY IN WISCONSIN...BUT CONFIDENCE NOT HIGH ENOUGH RIGHT NOW AMIDST OVERWHELMING DRY SIGNAL IN MOST DATASETS. LONG TERM...WEDNESDAY THROUGH SATURDAY LOW CONFIDENCE REGARDING EVOLUTION OF THE PESKY CUTOFF LOW OVER THE TX/OK AREA...AND WHETHER THIS WILL SINK FAR ENOUGH SOUTH TO AVOID BEING SWEPT NORTHWARD INTO THE FORECAST AREA THUR/FRI AHEAD OF VIGOROUS SHORTWAVE TROUGH SET TO RUN ACROSS SRN CANADA WED-SAT. WHEN INSPECTING NEW 16.12Z ECMWF/CANADIAN...AND MANY OF THE 16.06Z GEFS MEMBERS...THERE HAS BEEN A PROPENSITY FOR THE BULK OF THIS LATEST DATA TO TREND THE CUTOFF SO FAR SOUTH INTO TX THAT BY THE TIME THE AMBIENT FLOW INCREASES AHEAD OF THE SRN CANADA ENERGY...THAT THE CUTOFF IS TOO FAR SOUTH TO BE ABSORBED INTO THE STRONGER WIND FIELD...LEAVING THURS/FRI LARGELY DRY...WITH AT THE MOST SOME VERY ELEVATED/ACCAS TYPE SHOWERS AS SOME OF THE MID/HIGH LEVEL MOISTURE PEELS OFF INTO THE MID-MS VALLEY. THIS MANIFESTED IN VERY LOW GEFS PROBABILITIES FOR MEASURABLE PCPN THESE PERIODS. BUT MODEL TRENDS/CONTINUITY ON THUR/FRI ARE NOT GOOD...WITH MODELS MENTIONED ABOVE NOT HAVING LOCKED INTO THIS DRIER TREND/CUTOFF LOW LOCATION SOUNDLY YET...AND IN ADDITION...NEW 16.12Z GFS PAINTS A PRETTY WET SCENARIO THUR NIGHT/FRI AS THIS LOW DOES INDEED MOVE STRAIGHT NORTH THROUGH THE AREA. SO WILL MAINTAIN THE LOW RAIN CHANCES BEGINNING THURS AND CONTINUING INTO FRIDAY IN THE DATABASE...WITH THE NOTION THAT THERE IS BUILDING EVIDENCE THAT A GOOD PORTION OF THESE DAYS WILL BE DRY...WARM...AND MODERATELY HUMID AS LOW LEVEL MOISTURE CONTINUES TO BUILD UNDER THE LARGER SCALE RIDGE THROUGH WHICH THIS CUTOFF LOW WOULD HAVE TO MOVE. ON SATURDAY...GROWING CONFIDENCE/CONTINUITY IN ABOVE MENTIONED MODELS THAT SRN CANADA ENERGY WILL SWEEP EAST QUICKLY WITH STRONG COLD FRONT INTO THE AREA NEXT WEEKEND WITH BETTER RAIN THREATS AND POSSIBLY SEVERE WEATHER. BY THEN...MOISTURE WILL BE AMPLE WITH STRONG WIND FIELDS. HIGH PRESSURE TO FOLLOW THIS SYSTEM INTO EARLY NEXT WEEK. BINAU AVIATION... 500 MB RIDGE/NORTHWEST FLOW...ALONG WITH AN AREA OF HIGH PRESSURE HOLDING ACROSS THE MID MISSISSIPPI RIVER VALLEY...WILL KEEP THE REGION UNDER PREDOMINANTLY VFR CONDITIONS THROUGH THE EARLY PART OF NEXT WEEK. WEAK SFC BOUNDARY AND SHORTWAVE TROUGH ACROSS NORTHERN MN/WI HAS TO THE POTENTIAL TO SPARK ISOLATED SHRA/TS LATE THIS AFTERNOON/EVENING...BUT THIS ACTIVITY LOOKS TO HOLD MOSTLY ACROSS NORTHERN WI. BUILDING INSTABILITY ACROSS CENTRAL MN COULD RESULT IN SOME SPOTTY SHRA/TS ALSO...BUT AGAIN...BELIEVE KRST/KLSE WILL AVOID THIS THREAT. WINDS WILL DECOUPLE IN THE RIVER VALLEYS TONIGHT...BUT 10 KT WINDS JUST OFF THE SFC SHOULD KEEP THE ATMOSPHERE STIRRED ENOUGH WHERE WIDESPREAD VALLEY FOG SHOULD NOT BE A CONCERN. WILL NOT ADD MENTION TO KLSE AS A RESULT. TIGHTENING PRESSURE GRADIENT FOR SUNDAY WILL LEAD TO SLIGHTLY HIGHER WESTERLY WINDS COMPARED TO TODAY. A FEW AFTERNOON CU ARE EXPECTED...BUT WITH THE LINGERING SFC BOUNDARY STILL TO THE NORTHEAST...DO NOT SEE A SHRA/TS THREAT AT THIS TIME. RIECK && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ 01/01 wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 308 PM CDT SAT AUG 16 2008 .SHORT TERM...THROUGH TUESDAY NIGHT WARMEST STINT OF THIS COOL SUMMER SET TO COME THIS FORECAST CYCLE...AND VERY LOW/PESKY RAIN THREATS THE CONCERN THROUGH THE SHORT TERM. CURRENTLY...EXPANSIVE SFC HIGH PRESSURE ACROSS NEB/IA/KS/MO IN CONTROL WITH CONTINUED PLEASANT WEATHER. GOES WATER VAPOR LOOPS SHOWING SEVERAL FEATURES OF INTEREST...THE FIRST OF WHICH IS A WEAK SHORTWAVE IN WRN ONTARIO...A COMPACT AND STRONG CUTOFF LOW OVER UT/CO...AND A STRONGER SHORTWAVE OVER SASK/ALBERTA. GOES VISIBLE IMAGERY SHOWS LARGE DIURNALLY DRIVEN CUMULUS FIELD OVER ENTIRE CNTL CONUS. DEEP MOISTURE LOCKED UP WAY SOUTH OVER THE SRN CONUS...WITH MODIFIED AREA OF HIGH THETA-E AND SEASONABLE PWATS OVER MN/NRN WI AHEAD OF THE ONTARIO SHORTWAVE. ACCAS/-SHRA ALSO NOTED IN FORCED ASCENT REGION AHEAD OF THIS WAVE IN NERN MN/UPPER MICHIGAN. WESTERLY BREEZES NORTH OF THE SFC HIGH ALLOWING DEWPOINTS AGAIN TO MIX INTO THE LOWER 50S OVER THE FORECAST AREA AS TEMPS IN THE UPPER 70S TO LOWER 80S. RUC ANALYSIS /16.18Z/ SHOWS MASSIVE MIDLEVEL WRN CONUS RIDGE/NERN CONUS TROUGH...WITH STRONG CUTOFF LOW IN CO/UT TUCKED NICELY INTO SERN FLANK OF WRN RIDGE...A QUASI REX-BLOCKING STRUCTURE. THE 16.12Z DETERMINISTIC RUNS OF NAM-WRF/GFS/GEM ALL CONTINUE GENERAL DRY TREND...WITH SOME CAVEATS. IN GENERAL...THE NAM-WRF REMAINS THE MOST EAGER TO DEVELOP QPF...HAS HIGHER INSTABILITY...AND HIGHER PWATS...DUE WHAT SEEMS TO BE AN OVERESTIMATION OF BOUNDARY LAYER MOISTURE. HOWEVER...ITS HIGHER RESOLUTION NEEDS TO BE CONSIDERED HERE...SO THERE IS LOWER THAN NORMAL CONFIDENCE ON THE LOW STORM THREATS OVER MN/WI OVER THE NEXT FEW DAYS. TONIGHT...ONTARIO SHORTWAVE DRIVES SOUTHEAST THROUGH UPPER GREAT LAKES WITH A VERY WEAK/ALMOST NONEXISTENT LOW CONVERGENCE AXIS. RUC13 ALL DAY AS WELL AS NAM-WRF HAS WANTED TO CONVECT ACROSS CNTL MN INTO NERN MN BACK INTO ERN SD...AND THIS YET TO HAPPEN THROUGH 20Z. ANALYSIS OF TAMDARS /MSP/ CONFIRM LOW LEVEL MOISTURE TOO HIGH IN RUC/NAM...THUS LARGER SCALE TRENDS OF GFS/SREF/LOCALLY RUN ARW-WRF OF KEEPING VERY ISOLD-SCT DEVELOPMENT THROUGH THE EVENING HOURS LOOKS GOOD. DO EXPECT THIS ISOLD/SCT CONVECTION TO DEVELOP INTO NRN WISCONSIN THIS EVENING WHERE FORCING FOR ASCENT AND STEEPEST LOW LEVEL LAPSE RATES JUXTAPOSED...AND QUESTION BECOMES WHETHER THIS CAN DRIBBLE INTO NRN/ERN FORECAST AREA OVERNIGHT. GIVEN MORE EVIDENCE OF A RAPID DIMINISHING TREND AFTER SUNSET IN THE MODELS WHICH ARE CAPTURING CURRENT CONVECTIVE TRENDS BETTER...HAVE DECIDED TO KEEP RAIN OUT OF THE NRN/ERN AREAS THIS EVENING. BUT THIS NEEDS TO BE WATCHED CLOSELY. IF SOMETHING MORE ORGANIZED CAN GET GOING OVER NRN WI...STORMS COULD MAINTAIN INTO ERN FORECAST AREA OVERNIGHT. THINK VALLEY FOG LESS WIDESPREAD TONIGHT...AND CONFINED TO WI RIVER VALLEY DUE TO WARMER OVERNIGHT LOWS/MORE BOUNDARY LAYER FLOW ON NORTH SIDE OF HIGH. SUNDAY-TUESDAY...AGAIN...LARGELY A DRY PERIOD HERE WITH VERY WARM TEMPERATURES AS WARM NOSE WRAPPED AROUND CNTL PLAINS HIGH PRESSURE IS ADVECTED IN FROM WEST/NORTHWEST. MAY VERY WELL SEE SOME AREAS AROUND 90F DURING THIS ENTIRE PERIOD...WITH MOISTURE IN THE LOW LEVELS SLOWLY INCREASING. SEVERAL MORE WEAK WAVES IN THE NORTHWEST FLOW WILL SERVE TO DEVELOP/TIGHTEN A SWRD MOVING BAROCLINIC ZONE THROUGH WISCONSIN ON MONDAY AND TUESDAY...WHICH IS THE TAIL END OF A MORE SYNOPTIC SCALE FRONT DROPPING SOUTH AS NERN CONUS TROUGH REDEVELOPS AS THIS ENERGY MOVES INTO THE TROUGH. HERE AGAIN...16.12Z NAM-WRF IS MOST ROBUST WITH CAPE/INSTABILITY/PWATS AND IS MORE EAGER TO DEVELOP SPOTTY/ISOLD STORMS DIURNALLY AS CUMULUS FORMS AND CINH IS SMALL EACH AFTERNOON. WILL PROBABLY HAPPEN...BUT LARGER SCALE RIDGE BUILDING IN BY TUESDAY DOESN/T OFFER MUCH SUPPORT...AND THINK ANY STORM DEVELOPMENT SUN-TUES WILL BE VERY HARD TO PIN DOWN AND GIVEN LACK OF LARGER SCALE FORCING SIGNAL. THIS IS LIKELY WHY COARSE/GLOBAL MODELS SUCH AS GFS/ECMWF/GEM ALL REMAIN MAINLY DRY ASIDE FROM A SPECKLE HERE AND THERE...AND WHY SREF PROBS FOR RAIN ARE SO LOW THROUGH THIS PERIOD. FURTHER INSPECTION OF THE THOSE 16.09Z SREF MEMBERS SHOWING MAINLY KAIN-FRITCH CONVECTIVE SCHEMES ALLOWING THIS SPOTTY ACTIVITY TO DEVELOP. WITH BULK OF EVIDENCE FAVORING A DRY PERIOD...INCLUDING LOCALLY RUN ARW WRF BASED ON GFS...HAVE DECIDED TO WAIT FOR A MORE CONVINCING LARGE SCALE FORCING SIGNAL /SHORTWAVE/ OR SURFACE BOUNDARY...BOTH OF WHICH RIGHT NOW ARE NOT AGREED UPON IN STRENGTH OR LOCATION. BOTTOM LINE...WOULD NOT BE SURPRISED TO SEE SMALL RAIN CHANCES BE ADDED AT SOME POINT IN THE SUN-TUES TIMEFRAME...MAINLY IN WISCONSIN...BUT CONFIDENCE NOT HIGH ENOUGH RIGHT NOW AMIDST OVERWHELMING DRY SIGNAL IN MOST DATASETS. .LONG TERM...WEDNESDAY THROUGH SATURDAY LOW CONFIDENCE REGARDING EVOLUTION OF THE PESKY CUTOFF LOW OVER THE TX/OK AREA...AND WHETHER THIS WILL SINK FAR ENOUGH SOUTH TO AVOID BEING SWEPT NORTHWARD INTO THE FORECAST AREA THUR/FRI AHEAD OF VIGOROUS SHORTWAVE TROUGH SET TO RUN ACROSS SRN CANADA WED-SAT. WHEN INSPECTING NEW 16.12Z ECMWF/CANADIAN...AND MANY OF THE 16.06Z GEFS MEMBERS...THERE HAS BEEN A PROPENSITY FOR THE BULK OF THIS LATEST DATA TO TREND THE CUTOFF SO FAR SOUTH INTO TX THAT BY THE TIME THE AMBIENT FLOW INCREASES AHEAD OF THE SRN CANADA ENERGY...THAT THE CUTOFF IS TOO FAR SOUTH TO BE ABSORBED INTO THE STRONGER WIND FIELD...LEAVING THURS/FRI LARGELY DRY...WITH AT THE MOST SOME VERY ELEVATED/ACCAS TYPE SHOWERS AS SOME OF THE MID/HIGH LEVEL MOISTURE PEELS OFF INTO THE MID-MS VALLEY. THIS MANIFESTED IN VERY LOW GEFS PROBABILITIES FOR MEASURABLE PCPN THESE PERIODS. BUT MODEL TRENDS/CONTINUITY ON THUR/FRI ARE NOT GOOD...WITH MODELS MENTIONED ABOVE NOT HAVING LOCKED INTO THIS DRIER TREND/CUTOFF LOW LOCATION SOUNDLY YET...AND IN ADDITION...NEW 16.12Z GFS PAINTS A PRETTY WET SCENARIO THUR NIGHT/FRI AS THIS LOW DOES INDEED MOVE STRAIGHT NORTH THROUGH THE AREA. SO WILL MAINTAIN THE LOW RAIN CHANCES BEGINNING THURS AND CONTINUING INTO FRIDAY IN THE DATABASE...WITH THE NOTION THAT THERE IS BUILDING EVIDENCE THAT A GOOD PORTION OF THESE DAYS WILL BE DRY...WARM...AND MODERATELY HUMID AS LOW LEVEL MOISTURE CONTINUES TO BUILD UNDER THE LARGER SCALE RIDGE THROUGH WHICH THIS CUTOFF LOW WOULD HAVE TO MOVE. ON SATURDAY...GROWING CONFIDENCE/CONTINUITY IN ABOVE MENTIONED MODELS THAT SRN CANADA ENERGY WILL SWEEP EAST QUICKLY WITH STRONG COLD FRONT INTO THE AREA NEXT WEEKEND WITH BETTER RAIN THREATS AND POSSIBLY SEVERE WEATHER. BY THEN...MOISTURE WILL BE AMPLE WITH STRONG WIND FIELDS. HIGH PRESSURE TO FOLLOW THIS SYSTEM INTO EARLY NEXT WEEK. BINAU && .AVIATION... 500 MB RIDGE/NORTHWEST FLOW...ALONG WITH AN AREA OF HIGH PRESSURE HOLDING ACROSS THE MID MISSISSIPPI RIVER VALLEY...WILL KEEP THE REGION UNDER PREDOMINANTLY VFR CONDITIONS THROUGH THE EARLY PART OF NEXT WEEK. WEAK SFC BOUNDARY AND SHORTWAVE TROUGH ACROSS NORTHERN MN/WI HAS TO THE POTENTIAL TO SPARK ISOLATED SHRA/TS LATE THIS AFTERNOON/EVENING...BUT THIS ACTIVITY LOOKS TO HOLD MOSTLY ACROSS NORTHERN WI. BUILDING INSTABILITY ACROSS CENTRAL MN COULD RESULT IN SOME SPOTTY SHRA/TS ALSO...BUT AGAIN...BELIEVE KRST/KLSE WILL AVOID THIS THREAT. WINDS WILL DECOUPLE IN THE RIVER VALLEYS TONIGHT...BUT 10 KT WINDS JUST OFF THE SFC SHOULD KEEP THE ATMOSPHERE STIRRED ENOUGH WHERE WIDESPREAD VALLEY FOG SHOULD NOT BE A CONCERN. WILL NOT ADD MENTION TO KLSE AS A RESULT. TIGHTENING PRESSURE GRADIENT FOR SUNDAY WILL LEAD TO SLIGHTLY HIGHER WESTERLY WINDS COMPARED TO TODAY. A FEW AFTERNOON CU ARE EXPECTED...BUT WITH THE LINGERING SFC BOUNDARY STILL TO THE NORTHEAST...DO NOT SEE A SHRA/TS THREAT AT THIS TIME. RIECK && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 151 PM CDT FRI AUG 15 2008 .SHORT TERM... UPPER LOW VICINITY OF THE EASTERN GREAT LAKES WILL PUSH SLOWLY EAST. RUC SHOWS STEEPER LAPSE RATES BELOW 700 MB. JUST ENOUGH MOISTURE ON LAKE BREEZE BOUNDARY TO SET OFF ISOLATED SHOWER. HOWEVER WITH LIMITED CAPE AND WITH DRYING IN MID LEVELS THESE SHOWERS SHOULD NOT DEVELOP ANY MORE. SOME PATCHY FOG POTENTIAL WITH SURFACE HIGH...MAINLY IN RIVER VALLEYS. WEAK NORTHWEST UPPER FLOW AS EASTERN GREAT LAKES LOW OPENS AND MOVES OFF TO NEW ENGLAND. VERY WEAK VORT/SHORTWAVE FOR MONDAY AND MONDAY NIGHT. LIMITED MOISTURE AND CAPE SO WILL HAVE MAINLY DRY FORECAST EXCEPT FOR SLIGHT CHANCE OF THUNDERSTORMS NORTH TOWARD FOND DU LAC AND SHEBOYGAN...CLOSER TO SHORTWAVE. AS SURFACE HIGH GRADUALLY MOVES SOUTH...A GRADUAL WARMING TREND BEGINS WITH WEST 850 MB FLOW FROM THE NORTHERN PLAINS. .LONG TERM... BOTH GFS AND 00Z ECMWF GRADUALLY BUILD UPPER RIDGE OVER THE UPPER MISSISSIPPI VALLEY AND WESTERN GREAT LAKES TUESDAY...AND OVER THE GREAT LAKES WEDNESDAY. SHORTWAVE APPROACHES THURSDAY...BUT IS WEAKER ON ECMWF. WITH LARGE SURFACE HIGH RETREATING...AND WEAK SOUTH WINDS...EXPECT SOME INCREASE IN MOISTURE...BUT PREFER THE WEAKER FLOW AND DRIER ECMWF FOR NOW. TEMPERATURES WILL CONTINUE TO BE VERY WARM. && .AVIATION... DRY CANADIAN HIGH PRESSURE BUILDING INTO WI WITH VFR CONDITIONS THRU THE WEEKEND. SOME PATCHY...SHALLOW GROUND FOG CAN BE EXPECTED TONIGHT...BUT CERTAINLY NOT ENOUGH TO MAKE MENTION IN THE TAFS. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ SHORT/LONG TERM...06/HENTZ AVIATION/MARINE...18/BORGHOFF wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 350 AM EDT SUN AUG 17 2008 .SYNOPSIS... WEAK HIGH PRESSURE WILL PERSIST ACROSS THE CENTRAL APPALACHIANS...AS A WEAK BOUNDARY REMAINS OVER THE COASTAL PLAIN THROUGH MONDAY. TROPICAL STORM FAY IS EXPECTED TO BEGIN TO TURN TOWARD THE NORTH TONIGHT AND MONDAY...AS IT MOVES ACROSS CUBA. && .NEAR TERM /THROUGH TONIGHT/... NOCTURNAL CONVECTION BEGINNING TO DISSIPATE AS LOW LVL UPSLOPE FLOW WKNS DURING THESE WEE MORNING HOURS. A POTENT VORT MAX WAS WELL DEFINED ON W/V AND RUC H5 ANALYSIS OVR THE CWFA AT 06Z. THIS VORT WILL SLOWLY SHFT E...WITH AN NVA REGIME MOVG OVR THE AREA DURING THE DAY. THIS AFTN...THERE MAY BE ENUF SUBSIDENCE TO KEEP THE AREA CAPPED. THE GFS SHOWS LOW LVL MOISTURE REMAINING ACRS THE PIEDMONT...AS LOW LVL FLOW VEERS TO SELY. THE SREF IS MORE LIKE THE NAM IN KEEPING THE AREA RELATIVELY STABLE (PROB OF CAPE > 1000 J/KG < 20%). BOTH THE NAM AND SREF STILL INDICATE A FEW ISOLD MTN SHWRS AND TSTMS...HWVR. SO I TWEAKED GRIDS TO INCLUDE ENTIRE FA IN SLGT CHC POP (WITH LOW-END CHC ALONG CAE CWFA BORDER). MAX TEMPS WILL BE ABOUT THE SAME AS YDA (70S TO LWR 80S MTNS AND UPR 80S FOOTHILLS/PIEDMONT). TONIGHT...MODEL T-SECTIONS SHOW NOCTURNAL SELY LLJ DEVELOPING LIKE WE HAD THIS MORNING (SATURDAY NIGHT). THE GFS HAS LESS INSTBY AFTER 00Z THEN WHAT WAS ANALYZED WITH YDA/S CONVECTION. ALSO...ONLY SOME WK RIPPLES IN THE UPR LVLS WILL BE THERE TO SUPPORT CONVECTION. SO JUST A SLGT CHC POP FOR THE BLUE RIDGE ESCARPMENT FROM I-40 AND S...TO THE UPR SAVANNAH VLY. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 330 AM SUNDAY...LTL CHG WAS MADE TO THE SHORT TERM...AS AIR MASS CHGS LTL...AND MODELS ARE IN FAIR AGREEMENT THRU THIS PERIOD. ALL EYES ON TS FAY...WHICH IS EXPECTED TO BE INVOF HAVANA...CUBA BY ERLY MONDAY. WK SFC HI PRES WILL PERSIST ACRS THE OH VLY TO THE MID ATLANTIC...RESULTING IN ELY LOW LVL FLOW. A COASTAL FRONT/TROF OF SORTS WILL STRENGTHEN FROM GA TO CAPE HATTERAS...OUT AHEAD OF FAY. THIS LOOKS TO BE THE FOCUS FOR CONVECTION...WHICH SHUD KEEP MOST OF THE DEEPER MOISTURE OUT OF OUR AREA UNTIL LATER IN THE WEEK. SO GENERALLY ONLY A FEW ISOLD SHWRS/TSTMS CAN BE EXPECTED AT MOST ON MONDAY...WITH A SLIGHTLY HIER CHC ON TUESDAY...AS SAID BNDRY BEGINS TO ADVANCE INLAND A BIT. OTRW...TEMPS SHUD STAY ABOUT NORMAL THRU TUESDAY. AGAIN...THIS IS A RATHER LOW CONFIDENCE FCST...AS THE STRENGTH AND LOCATION OF FAY MAY RESULT IN MORE SUBSIDENCE OVR THE AREA TUESDAY (AND THUS DRIER CONDITIONS). && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 330 AM SUNDAY...THE LATEST NHC FCST AND THE 00Z/17 GFS ARE IN GOOD AGREEMENT FOR THE TRACK OF TS FAY. THE 2 AM NHC FCST PEGS FAY AS A DEPRESSION OVR ELBERT COUNTY AT 00Z/22. SO I BLENDED THE 00Z MEX TO RAISE POPS WEDNESDAY AND THURSDAY TO MATCH THE STRONGER CONFIDENCE IN FAY`S LIKELY AFFECT ON THE WX ACRS THE CWFA. FOR NOW...A MID- TO HIGH-END CHC BOTH DAYS...WITH MAX TEMPS ADJUSTED DOWN A CAT OR TWO. ATTM...QPF AMTS ARE STILL HIGHLY UNCERTAIN. HWVR...IF THE CURRENT FCST TRACK VERIFIES...OUR AREA SHUD SEE SIGNIFICANT WIDESPREAD RAINFALL BY LATE NEXT WEEK. A MENTION OF THIS RAINFALL POTENTIAL WILL BE PLACED IN THE HWO. && .AVIATION /08Z SUNDAY THROUGH THURSDAY/... WEAK BNDRY WILL DROP SOUTH ACROSS THE AREA TONIGHT. STRONG STORMS HAVE DEVELOPED ALONG THE BNDRY BETWEEN KHKY AND KCLT. STORMS WILL LIKELY BUILD BACK INTO KHKY THE NEXT COUPLE HOURS. I THINK THEY WILL STAY NORTH OF KCLT...BUT IT WILL BE CLOSE. MANY SITES WILL SEE FOG OVERNIGHT WITH THE HIGHER DEWPOINTS...THOUGH HIGH CLOUDS SHOULD KEEP IT FROM BECOMING DENSE. LIGHT NORTHEAST FLOW THIS MORNING WILL BECOME LIGHT SOUTHEAST THIS AFTERNOON. PLENTY OF CU WILL DEVELOP WITH DAYTIME HEATING...BUT I WON/T INCLUDE CB/S QUITE YET AS IT LOOKS A LITTLE MORE STABLE TODAY AND THIS EVENING. OUTLOOK...SFC FRONT REMAINS JUST S OF AREA MON. PRECIP CHANCE APPEARS MINIMAL THROUGH THE PERIOD. TROPICAL STORM FAY MAY APPROACH FROM THE S AROUND MID WEEK. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...ARK NEAR TERM...ARK SHORT TERM...ARK LONG TERM...ARK AVIATION...MCAVOY sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX 315 AM CDT SUN AUG 17 2008 .DISCUSSION... INVERTED SFC TROF ANALYZED FROM LAREDO TO HONDO TO LLANO AT MIDNIGHT. A CONVERGENCE WAS ALSO ANALYZED FROM JUST NORTH OF LAREDO EAST TO JUST NORTH OF CORPUS CHRISTI. THE INTERSECTION IS KEEPING RAIN GOING ACROSS MAVERICK AND DIMMIT COUNTIES. THE RUC PICKS UP ON THE CONVERGENT BOUNDARY AND HAS IT STATIONARY THIS MORNING. MODELS NOT DOING TOO GOOD WITH SURFACE FEATURES BECAUSE OF THE MANY OUTFLOW BOUNDARIES. HOWEVER, THE UPPER LEVELS ARE ALL INITIALIZED WELL WITH 00Z UPPER AIR PLOTS. BETTER ORGANIZED RAIN WILL SHAPE UP TODAY WITH THE 700MB TROF MOVING SOUTHEAST TOWARD THE RIO GRANDE. THE RIO GRANDE REGION IS EXPECTED TO RECEIVE EXCESSIVE RAIN TODAY LEADING TO LOCALIZED FLOODING. THE 700MB TROF IS PROGGED TO DRIFT EASTWARD ACROSS THE CWA OVER THE NEXT 3 DAYS. WITH THE TROPICAL AIR OVER US, LOCALLY HEAVY RAIN AND THE POSSIBILITY OF FLASH FLOODING WILL BE WITH US THROUGH AT LEAST TUESDAY. WILL START A FLASH FLOOD WATCH FOR THE WESTERN HALF OF THE CWA WHERE RAIN SHIELD IS PERSISTING (ROUGHLY ALONG AND WEST OF A LLANO TO PEARSALL LINE). IT IS LIKELY THE WATCH WILL NEED RECONFIGURING AS THIS RAIN EVENT EVOLVES. BY MIDWEEK (WEDNESDAY) THE UPPER TROF AXIS IS PROGGED TO SLICE NORTH-SOUTH ALONG I-35 WITH HIGH P.W.`S OVER THE EASTERN THIRD OF THE CWA, KEEPING THE RISK OF FLASH FLOODING RAINS GOING EAST OF I-35. SOIL MOISTURE SHOULD BE REPLENISHED BY LATTER HALF OF NEXT WEEK. THEREFORE, MAX TEMPS WILL HOVER NEAR SEASONAL NORMALS FOR THE WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 88 69 88 70 84 / 80 80 80 60 60 AUSTIN BERGSTROM INTL AIRPORT 87 69 89 68 84 / 80 80 80 60 60 DEL RIO INTL AIRPORT 87 72 86 71 88 / 100 100 70 50 50 SAN ANTONIO INTL AIRPORT 87 72 86 71 85 / 90 90 80 60 60 && .EWX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR THE FOLLOWING COUNTIES: BANDERA...DIMMIT...EDWARDS...FRIO...GILLESPIE...KERR... KINNEY...LLANO...MAVERICK...MEDINA...REAL...UVALDE...VAL VERDE... ZAVALA. && $$ 06/11 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 351 AM CDT SUN AUG 17 2008 .DISCUSSION...MAIN FOCUS ON DRY AND WARM WEATHER REGIME INTO MID WEEK. TODAY- WEAK SHORTWAVE THAT GENERATED ISOLD/SCT STORMS ACROSS NORTHERN WI SHIFTING SOUTH OF HERE THIS MORNING. RADAR TRENDS SHOW THE ACTIVITY VERY ISOLATED BUT STILL HOLDING TOGETHER ACROSS OUR NORTHERN CWA. WILL HAVE MENTION IN GRIDS EARLY ON THROUGH 12Z FOR NOW. WATER VAPOR/RUC SUPPORT GENERAL RIDGING TAKING HOLD FOR TODAY. H7 PROGS SHOW LINGERING MID LEVEL MOISTURE AROUND THIS MORNING. WEST/SOUTHWEST 850 MILLIBAR FLOW WILL ADVECT WARMER TEMPERATURES TODAY WITH NO LAKE BREEZE EXPECTED. TONIGHT- WEAK SURFACE AND 850 MILLIBAR RIDGING WITH LITTLE IN THE WAY OF FORCING UPSTAIRS...THUS THE DRY WEATHER CONTINUES. MONDAY- MODELS SHOWING A 500 MILLIBAR WAVE COMING DOWN IN THE NORTHWEST FLOW. THERE IS ALSO A SHALLOW FRONT THAT IS SLIDING INTO THE CWA DURING THE AFTERNOON AND EVENING HOURS. PRECIPITATION DEVELOPMENT ON THE MODELS IS TIED MORE TO THE 850 MILLIBAR BAROCLINIC RIBBON ACROSS NORTHERN WISCONSIN. TUESDAY THROUGH WEDNESDAY NIGHT- DOMINATED BY SURFACE AND 850 MILLIBAR RIDGING HOWEVER 500 MILLIBAR FLOW SUGGEST WEAK WAVES WITHIN A RATHER DIFFUES LOOKING UPPER FLOW PATTERN. HARD TO LATCH ONTO MUCH HERE AT THIS POINT. LOW LEVEL FLOW LOOKS TO BECOME A LITTLE MORE FAVORABLE FOR MOISTURE/INSTABILITY RETURN ON WEDNESDAY...HOWEVER FORCING STILL A BIG QUESTION MARK. ADVERTISING DRY STILL LOOKS BETTER AT THIS JUNCTURE THAN GETTING HOPES HIGH FOR IFFY RAIN CHANCES. THURSDAY- GFS BRINGS UPPER LOW NORTHEAST INTO THE AREA FOR THURSDAY AND THURSDAY NIGHT. MEANWHILE THE ECMWF ESSENTIALLY KEEPS CWA DRY UNTIL SATURDAY. GFS DPROGS THURSDAY NIGHT WOULD ACTUALLY BE A BETTER SHOT THAN THURSDAY BASED ON THE MORE CONSISTENT SIGNAL FROM THE MODEL TRENDS. THE ECMWF HAS SHOWN CONSISTENCY WITH THE DRY LOOK FOR THURSDAY/THURSDAY NIGHT. FOR NOW WILL STEER TOWARDS SLIGHT CHANCES FOR THURSDAY AND BUMP BARELY INTO CHANCY CATEGORY FOR THURSDAY NIGHT. && 10 .AVIATION...VFR THRU PERIOD. SOME MID/HIGH LEVEL CLOUDS EARLY WITH S/W PASSING TO THE NE/EAST OF AREA. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 1000 AM EDT SUN AUG 17 2008 .SYNOPSIS... 14Z WATER VAPOR AND H4 RUC ANALYSIS REVEALING A FAIRLY MESSY UPPER AIR PATTERN ACROSS NORTH AMERICA THIS MORNING. SHOWING LONGWAVE RIDGING OVER MUCH OF THE WEST...HOWEVER THE PERSISTENT CUTOFF UPPER LOW CONTINUES TO SPIN IN PLACE OF COLORADO PINCHING INTO THE EASTERN SIDE OF THIS RIDGE. NO BIG SURPRISE TO FIND LONGWAVE TROUGHING FURTHER TO THE EAST COVERING THE EASTERN THIRD OF THE NATION AS THIS HAS BEEN A SEMI-PERMANENT FEATURE THIS SUMMER. THIS TROUGH CURRENTLY EXTENDS ITS AXIS DOWN THE SPINE OF THE APPALACHIANS TO THE NORTHEAST GULF COAST. PERIODIC PIECES OF MID-LEVEL ENERGY CONTINUE TO ROUND THE BASE OF THIS TROUGH ACROSS OUR FORECAST AREA WITH ONE SHORTWAVE EXITING OFF THE GA COAST THIS MORNING AND ANOTHER WEAKER SHORTWAVE PROGGED BY LATEST GFS/NAM TO CROSS DURING THE AFTERNOON HOURS. AT THE SURFACE...WEAK PRESSURE GRADIENT OVER THE AREA TODAY WITH A LIGHT AND VARIABLE MEAN 1000-700MB FLOW. SURFACE WINDS WILL BE MORE INFLUENCED BY AFTERNOON SEA-BREEZE CIRCULATIONS AND SCT SHOWER/STORM OUTFLOW THAN BY THE GRADIENT. A MIX OF CLOUDS AND SUN ACROSS THE AREA THIS MORNING WITH A BALANCE TIPPED MORE TOWARD THE CLOUDS SIDE. SHOULD SEE MORE AND MORE BREAKS OF SUN AS WE HEAD INTO THE AFTERNOON HOURS. KEVX/KTLH RADARS SHOWING A SCATTERING OF SHOWERS AND STORMS PUSHING WEST TO EAST ACROSS THE COASTAL WATERS WHICH IS FAIRLY TYPICAL DURING THE MORNING HOURS THIS TIME OF YEAR. TEMPERATURES RISING THROUGH THE UPPER 70S AND LOWER 80S ON THEIR WAY TO AFTERNOON HIGHS IN THE MIDDLE 80S TO NEAR 90. && UPDATE/DISCUSSION... REST OF TODAY INTO TONIGHT WILL FEATURES A MIX OF CLOUDS AND SUN. SCATTERED SHOWERS AND STORMS EXPECTED NEAR THE COAST INTO THE EARLY AFTERNOON AS OFFSHORE CONVECTION OCCASIONALLY REACHES SHORE...ESPECIALLY ACROSS SOUTHERN GULF...FRANKLIN...TAYLOR AND DIXIE COUNTIES. MOIST PROFILE OFF THIS MORNINGS KTLH SOUNDING SHOWING A PW OVER 2". MODIFYING THIS PROFILE FOR AFTERNOON SURFACE CONDITIONS IN THE UPPER 80S OVER UPPER 60S TO LOWER 70S YIELDS BETWEEN 2000-2500 J/KG OF CAPE. NOT AN OVERLY IMPRESSIVE VALUE BUT WITHIN THE NORMAL RANGE FOR THIS TIME OF YEAR. DEPENDING ON JUST HOW MUCH DIURNAL HEATING WE CAN SQUEEZE OUT BETWEEN THE CLOUDS...EXPECTING SCT COVERAGE OF CONVECTION ALMOST REGION-WIDE DURING THE MIDDLE AFTERNOON HOURS INTO THE EARLY EVENING. COVERAGE MAY BE A BIT HIGHER ALONG AND SOUTH OF THE I-10 CORRIDOR WHERE SEA-BREEZE CONVERGENCE ADDS A LOW LEVEL CONVERGENCE FOCUS TO THE EQUATION. HOWEVER...EVEN WITHOUT A SIGNIFICANT SURFACE FOCUS...DO EXPECT WEAK MID-LEVEL ENERGY TO CROSS THE AREA THIS AFTERNOON ADDING A LIMITED AMOUNT OF LARGE-SCALE LIFT. CURRENT POP GRIDS SHOWING 40-50% COVERAGE NORTH AND 50-60% COVERAGE SOUTH. THIS MAY BE JUST A BIT ON THE HIGH SIDE BASED ON THE AMOUNT OF SUPPRESSIVE CLOUDCOVER...BUT WILL HOLD OFF ON MAKING ANY SIGNIFICANT CHANGES JUST YET AS DO EXPECT SUNSHINE TO INCREASE SOMEWHAT OVER THE NEXT FEW HOURS. MESSY UPPER LEVEL TROUGHING PATTERN CONTINUES OVERHEAD INTO TONIGHT. EXPECTING SCT EVENING SHOWERS AND STORMS TO FADE RAPIDLY AFTER SUNSET WITH THE LOSS OF DIURNAL HEATING...AND LEAVING PARTLY TO MOSTLY CLOUDY SKIES FOR THE REMAINDER OF THE OVERNIGHT. && .MARINE... VERY LIGHT GRADIENT ACROSS THE FORECAST WATERS THIS MORNING. LATEST OBSERVATIONS FOR THE BUOYS INDICATING VARIABLE WINDS LESS THAN 5 KNOTS WITH SEAS ONLY AROUND 1 FOOT. EXPECTING FLOW TO COME AROUND TO A WESTERLY DIRECTION BY THE END OF THE DAY BUT REMAIN LIGHT WITH SEAS BETWEEN 1 AND 2 FEET. SCATTERED SHOWERS AND STORM CONTINUING INTO THE AFTERNOON HOURS. NOT A WHOLE LOT OF CHANGE INTO THE OVERNIGHT HOURS WITH A VARIABLE FLOW GENERALLY LESS THAN 10 KNOTS WITH LIGHT SEAS. && .AVIATION... MVFR VSBY HAVE LIFTED WITH VFR EXPECTED INTO EARLY AFTERNOON. THEN...SHOWERS AND THUNDERSTORMS ARE AGAIN EXPECTED ESPECIALLY FL TERMINALS WITH TEMPOS FOR TSTMS AND MVFR CIGS/VSBYS BEGINNING 17-18Z WRN AND 18-19Z ERN TERMINALS...ENDING AROUND 22Z. THEN VFR ON TAP. AFT 09Z...MVFR FOR VSBYS/LIGHT RAIN FOR ALL TERMINALS EXCEPT PERHAPS KPFN. && .PREVIOUS DISCUSSION... ...TROPICAL STORM FAY FORECAST TO STRENGTHEN AND MOVE INTO EASTERN MOST GULF TUESDAY INTO WEDNESDAY... .SHORT TERM (TODAY THROUGH TUESDAY)...LINGERING TROUGHS AT SFC AND ALOFT WILL CONTINUE TO IMPACT THE WEATHER ACROSS THE REGION TODAY AND MONDAY. IR AND WATER VAPOR IMAGERY SHOW A WEAK DISTURBANCE IN THE UPPER FLOW WHICH WILL CROSS THE CWA DURING THE REMAINDER OF THE OVERNIGHT HOURS. AS THIS FEATURE CLEARS THE AREA...MAY SEE SOME BREAKS IN THE OVERCAST BY LATE THIS MORNING. MODELS THEN DEPICT ANOTHER WEAK RIPPLE IN THE FLOW MOVING IN FROM THE SOUTHWEST THIS AFTERNOON. THIS SHOULD LEAD TO GOOD COVERAGE OF CONVECTION THIS AFTERNOON...ESPECIALLY OVER THE FLORIDA ZONES. BY MONDAY...THE UPPER TROUGH IS EXPECTED TO WEAKEN AS A DEEP UPPER LOW DROPS INTO THE SOUTHERN PLAINS. HOWEVER...WILL STILL SEE SOME REMNANTS OF THE SFC TROUGH AROUND THE AREA AS WELL DEEP MOISTURE. THUS...STILL ANTICIPATE GOOD COVERAGE OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ONCE AGAIN. TUESDAY GETS MORE COMPLICATED AS WE BEGIN TO GET INFLUENCED BY THE CIRCULATION AROUND FAY. MOIST EASTERLY FLOW TO THE NORTH OF THE CIRCULATION COMBINED WITH ANY LINGERING REMNANT OF THE SFC TROUGH SHOULD LEAD TO ANOTHER WET DAY...ESPECIALLY OVER THE SOUTHEAST HALF OF THE CWA. OVERALL...WET PERIOD LOOKS TO CONTINUE THROUGH THE NEXT THREE DAYS. TEMPERATURES EXPECTED TO BE A LITTLE BELOW CLIMO FOR MOST LOCATIONS DUE TO ENHANCED CLOUD COVER. .LONG TERM (TUESDAY NIGHT THROUGH SUNDAY)...LATEST GUIDANCE SHOWS TROPICAL STORM FAY...OR WILL IT BE HURRICANE FAY...TO BEGIN TO AFFECT OUR AREA TUESDAY AFTERNOON...THE 34-KNOT WIND CONE SHOULD BEGIN TO AFFECT OUR SOUTHEASTERN COUNTIES BY 00Z TUESDAY NIGHT. WITH THE TRACK FORECAST NOW JUST EAST OF OUR CWA...THIS SHOULD LESSEN THE IMPACT ON OUR LOCAL CWA...BUT WILL KEEP THE POPS ABOVE CLIMO AND TEMPS NEAR OR A LITTLE BELOW CLIMO THROUGH WEDNESDAY INTO THURSDAY. AS FAY PROGRESSES NORTHWARD ON WEDNESDAY... TROUGH/SHORT WAVE COMING OUT OF THE ROCKIES INTO THE SOUTHERN PLAINS TODAY WILL BE LOCATED IN THE OK/TX REGION ACCORDING TO GFS. THIS SYSTEM IS A MAJOR PLAYER ON WHAT FAY WILL GO. ACCORDING TO THE GFS...THIS TROUGH GETS CAUGHT UP WITH ANOTHER APPROACHING TROUGH FROM THE PACIFIC NORTHWEST AND RAPIDLY FILLS AND PUSHES NORTHEAST. THE REMNANTS OF FAY REMNANT DOES MUCH THE SAME. THE 00Z EURO HAS ANOTHER SOLUTION. FAY TURNS QUICKLY NORTHEAST AND GETS STUCK FOR A FEW DAYS OFF THE ATLANTIC COAST AS A RIDGE TO THE NORTH BLOCKS ITS PATH. IN OUR AREA...THE GFS SOLUTION HAS AN UPPER RIDGE SETTLING IN BEHIND FAY THROUGH SATURDAY. ON SUNDAY...ANOTHER TROPICAL SYSTEM APPROACHES SOUTH FLORIDA AS A MID LATITUDE TROUGH APPROACHES FROM THE WEST...WHICH MAKES ANOTHER HEAVY WORK SCHEDULE IN OUR NECK OF THE WOODS. THE GFS AND EURO ARE SIMILAR...BUT THE GFS SHOWS MORE A VIGOROUS TROPICAL SYSTEM AS WELL AS MID LATITUDE SYSTEM. && .FIRE WEATHER...PLENTY OF DEEP MOISTURE THROUGH THE NEXT SEVERAL DAYS WILL KEEP HUMIDITY VALUES WELL ABOVE CRITICAL LEVELS. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 88 70 90 71 90 / 60 30 50 30 60 PANAMA CITY 86 73 88 75 88 / 50 30 50 20 50 DOTHAN 89 69 89 70 89 / 50 20 50 30 50 ALBANY 89 69 90 70 90 / 40 20 40 30 60 VALDOSTA 88 69 90 71 89 / 50 20 50 30 60 CROSS CITY 87 70 90 72 89 / 60 30 50 30 60 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...NONE. GM...NONE. && $$ SYNOPSIS/UPDATE/MARINE...MROCZKA AVIATION...BLOCK PREVIOUS DISCUSSION...CAMP/WATSON fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 1229 PM EDT SUN AUG 17 2008 .SYNOPSIS... A STALLED FRONT WILL REMAIN ACROSS SOUTHERN SOUTH CAROLINA BEFORE DISSIPATING MONDAY. AN UPPER LEVEL DISTRUBANCE WILL MOVE THROUGH THE AREA THROUGH THIS AFTERNOON PRODUCING AN INCREASED CHANCE OF SHOWERS AND THUNDERSTORMS. HIGH PRESSURE WILL BUILD EAST FROM THE PLAINS STATES MONDAY INTO TUESDAY. TROPICAL STORM FAY...CURRENTLY JUST SOUTH OF THE EASTERN END OF CUBA...IS FORECAST TO MOVE ALONG THE GULF COAST OF FLORIDA TUESDAY INTO WEDNESDAY...THEN STALL OVER GEORGIA OR THE INLAND CAROLINAS LATE IN THE WEEK. A COLD FRONT MAY MOVE SOUTH FROM THE MID- ATLANTIC REGION INTO THE CAROLINAS THURSDAY...ALSO STALLING NEARBY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 11 AM SUNDAY...A FEW SHWRS/TSTMS ALONG THE COAST THIS MORNING WERE RESPONSIBLE FOR SPAWNING WATERSPOUTS SOUTH OF BRUNSWICK CNTY AND NEAR SNOWS CUT BRIDGE. A COUPLE OF SPECIAL MARINE WARNINGS WERE ISSUED FOR THE WATERSPOUTS. THE FOCUS SHIFTED TOWARD INLAND COUNTIES BY MID MORNING WHERE SHWRS/TSTMS SHIFTED EAST OVER OUR CWA. PERIODS OF MODERATE TO HEAVY RAIN CONTINUED THROUGH THE MORNING HOURS. THESE AREAS OF CONVECTION SEEMED TO LINE UP NICELY WITH SOME IMPULSES MOVING THROUGH WITH VORT CENTERS TRACKING ACROSS THESE AREAS THIS MORNING. THE RUC CONTINUES TO SHOW THE BEST SHORTWAVE ENERGY OVER THE PIEDMONT AREA THROUGH THIS AFTERNOON AND TRACKING OFF TO THE NORTHEAST THROUGH THIS EVENING. DEEP LAYER MOISTURE CONTINUES ACROSS THE AREA WITH PCP WATER VALUES ON MORNING SOUNDINGS AROUND 1.75 INCHES. AREAS WHERE SHWRS/TSTMS OCCURRED THIS MORNING SHOULD HELP TO STABILIZE THE WESTERN SECTIONS THIS AFTERNOON. BOUNDARY OF MID TO UPPER DRY AIR STILL REMAINING NORTH OF AREA AS EVIDENT BY THE WATER VAPOR IMAGERY. DEW POINTS IN THE MID 50S WILL CONTINUE TO HOLD OFF WELL TO THE NORTH AND WEST NEAR THE NC BORDER WHILE OUR CWA REMAINS WITH DEW POINTS AROUND 70. TEMPS ACROSS GEORGETOWN AND WILLIAMSBURG WILL REACH INTO THE MID 80S THROUGH EARLY AFTERNOON...ESPECIALLY TOWARD THE COASTAL AREAS. AS MID TO UPPER LEVEL CLOUDS THIN THROUGH THE AFTERNOON TEMPS WILL CONTINUE TO RISE AND THERE SHOULD BE SOME AREAS OF DIFFENTIAL HEATING TO HELP SPARK SOME CONVECTION. EXPECT BEST COVERAGE ACROSS SC COUNTIES WHERE BEST HEATING...MOISTURE AND INSTABILITY LIES AND ALSO ALONG SEA BREEZE BOUNDARY AS IT MEETS UP WITH EARLIER BOUNDARIES FROM CONVECTION THIS MORNING. BY THIS EVENING...BEST SHORTWAVE ENERGY RIDES OFF TO THE NORTHEAST AND ONCE HEATING OF THE DAY CUTS OFF...EXPECT SHWRS/TSTMS TO TAPER OFF...ESPECIALLY ACROSS INLAND AREAS. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 AM SUNDAY...DRIER AIR PUSHING INTO THE AREA MON WILL LIMIT PRECIP CHANCES AND RESULT IN TEMPS A FEW DEGREES WARMER THAN PREVIOUS DAYS. STILL THINK SOME SHRA/TSRA ACTIVITY WILL BE AROUND...BUT IT WILL BE A RESULT OF DEVELOPING OVER THE WATERS OR ON THE SEA BREEZE AND SPREADING INLAND. HIGHEST POPS WILL BE ALONG THE IMMEDIATE COAST WITH SLT CHC TO NO CHC INLAND. THE NAM HAS FINALLY JOINED THE GFS/CANADIAN/UKMET WITH KEEPING FAY ON THE W COAST OF FL AS THE STORM HEADS N. THE NAM STILL WANTS TO MOVE THE STORM E...BUT NOT AS IT HAS IN EARLIER RUNS AND HAS AN END POINT SIMILAR TO THAT OF THE GFS. THE ECMWF CONTINUES TO STICK TO ITS GUNS AND TRACKS FAY ACROSS SRN FL...OFF THE E COAST OF FL AND TO POINTS ALONG THE SC/NC COAST. NHC TRACK IS IN LINE WITH THE GFS/CANADIAN AND HAS SHOWN LITTLE VARIABILITY DURING THE PAST DAY. THOUGH CONFIDENCE IS STILL LOW...DO FEEL A LITTLE BETTER ABOUT THE FORECAST THROUGH TUESDAY NIGHT. LOW AND MID LEVEL MOISTURE WILL BE INCREASING DURING THE DAY TUE AS FAY SPREADS TROPICAL MOISTURE N. EXPECT AN INCREASE IN CLOUD COVER AND SHRA/TSRA...ESPECIALLY ALONG THE COAST WHERE SPEED CONVERGENCE SHOULD ENHANCE ONGOING STORMS...TUE AFTN. INCREASED CLOUD COVER AND STORMS COVERAGE WILL LIKELY KEEP HIGHS A FEW DEGREES BELOW CLIMO WHILE LOWS RUN SLIGHT ABOVE CLIMO. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 3 AM SUNDAY...LARGE AMOUNT OF UNCERTAINTY PERSISTS THROUGH THE PERIOD WITH TROPICAL STORM FAY BEING THE MAIN CONCERN. LATEST GUIDANCE REMAINS IN GOOD AGREEMENT WITH NHC TRACK...ONLY THE ECMWF INSISTS ON THE STORM EMERGING OFF THE SE COAST. FAY MAY START TO HAVE AN INDIRECT IMPACT ON THE REGION AS EARLY AS WED WITH PLENTY OF TROPICAL MOISTURE SPREADING INTO THE AREA AHEAD OF THE STORM. THE MOIST SRLY FLOW WILL INTERACT WITH COLD FRONT DROPPING IN FROM THE N...RESULTING IN INCREASED PRECIP CHANCES WED. BECAUSE THERE IS SO MUCH UNCERTAINTY AND PRECIP CHANCES DURING THE PERIOD WILL HINGE ON WHERE FAY GOES...HAVE NOT MADE ANY SIGNIFICANT CHANGES TO THE LONG TERM FORECAST/GRIDS. BEST CHANCES CONTINUE TO BE ON THU/FRI BUT COULD LINGER INTO SAT IF FAY IS SLOW TO MOVE OUT OF THE AREA AS SOME GUIDANCE SUGGEST. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... THERE IS A LITTLE MVFR FOG AT THE TERMINALS THIS MORNING BUT IT SHOULD BE GONE BY 13Z OR SO WITH LIGHT NORTHEAST WINDS. SHOWERS AND THUNDERSTORMS ARE ALREADY DEVELOPING ACROSS INLAND AREAS AND VCTS IS NOTED IN ALL TERMINALS BY 18Z. PILOTS SHOULD BE PREPARED FOR CONVECTION NEAR AREA TERMINALS FROM THE PRESENT TIME THROUGH SHORTLY AFTER 00Z WITH THE STRONGEST ACTIVITY POSSIBLE IN THE 16Z- 22Z WINDOW. OUTLOOK THOUGH THURSDAY...THE EARLIEST IMPACT THAT T.S. FAY WOULD HAVE ACROSS THE TERMINALS WILL BE LATE WEDNESDAY INTO THURSDAY. OTHERWISE THROUGH THURSDAY...THERE WILL BE A CHANCE OF THUNDERSTORMS EACH DAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 3 AM SUNDAY...LIGHT NE TO E WINDS EXPECTED TODAY AND TONIGHT WITH SEAS 3 FT OR LESS. NO FLAGS. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 AM SUNDAY...LIGHT NE FLOW OVER THE WATERS EARLY MON AS DISSIPATING BOUNDARY LINGERS IN THE AREA. SFC FLOW GRADUALLY GAINS MORE OF AN ERLY COMPONENT AS SFC HIGH TRIES BUILDING IN FROM THE E. TROPICAL STORM FAY MAY HAVE A SECONDARY IMPACT...MAINLY A PINCHED GRADIENT AND SWELLS FROM THE CIRCULATION OF FAY LATE IN THE PERIOD. FAY WILL ALSO SPREAD PLENTY OF MOISTURE ACROSS THE REGION...INCREASE COVERAGE OF SHRA/TSRA ACROSS THE WATERS ON TUE. LONG TERM /WEDNESDAY THROUGH THURSDAY/... AS OF 3 AM SUNDAY...THE IMPACT TROPICAL STORM FAY WILL HAVE ON THE WATERS IS STILL UNCERTAIN...BUT BASED ON THE LATEST NHC TRACK S TO SE FLOW WED WILL GRADUALLY INCREASE DURING THE DAY AND BECOME MORE SRLY. AT THIS TIME SPEEDS ARE FORECAST TO REMAIN BELOW 25 KT...BUT ANY EWRD SHIFT IN THE TRACK OF FAY IS GOING TO RESULT IN AN INCREASE IN WIND SPEEDS. WITH FAY WELL INLAND ONSHORE FLOW WILL CONTINUE THROUGH THU WITH SPEEDS DECREASING LATER THU. SEAS 2 TO 4 FT WED WILL INCREASE TO 3 TO 5 FT BY THU. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...III NEAR TERM...RGZ SHORT TERM...III LONG TERM...III AVIATION...RAN nc AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX 627 AM CDT SUN AUG 17 2008 .AVIATION... A MIX OF MVFR AND VFR CIGS/VSBYS FORECAST THROUGH THE TAF PERIOD WITH SHOWERS AND THUNDERSTORMS...ALTHOUGH BRIEF PERIODS OF IFR CONDITIONS CAN NOT BE RULED-OUT WITH THE STRONGER STORMS. THUNDERSTORM COVERAGE WILL INCREASE THIS AFTERNOON NEAR I-35 TERMINALS. && .PREV DISCUSSION... /ISSUED 315 AM CDT SUN AUG 17 2008/ DISCUSSION... INVERTED SFC TROF ANALYZED FROM LAREDO TO HONDO TO LLANO AT MIDNIGHT. A CONVERGENCE WAS ALSO ANALYZED FROM JUST NORTH OF LAREDO EAST TO JUST NORTH OF CORPUS CHRISTI. THE INTERSECTION IS KEEPING RAIN GOING ACROSS MAVERICK AND DIMMIT COUNTIES. THE RUC PICKS UP ON THE CONVERGENT BOUNDARY AND HAS IT STATIONARY THIS MORNING. MODELS NOT DOING TOO GOOD WITH SURFACE FEATURES BECAUSE OF THE MANY OUTFLOW BOUNDARIES. HOWEVER, THE UPPER LEVELS ARE ALL INITIALIZED WELL WITH 00Z UPPER AIR PLOTS. BETTER ORGANIZED RAIN WILL SHAPE UP TODAY WITH THE 700MB TROF MOVING SOUTHEAST TOWARD THE RIO GRANDE. THE RIO GRANDE REGION IS EXPECTED TO RECEIVE EXCESSIVE RAIN TODAY LEADING TO LOCALIZED FLOODING. THE 700MB TROF IS PROGGED TO DRIFT EASTWARD ACROSS THE CWA OVER THE NEXT 3 DAYS. WITH THE TROPICAL AIR OVER US, LOCALLY HEAVY RAIN AND THE POSSIBILITY OF FLASH FLOODING WILL BE WITH US THROUGH AT LEAST TUESDAY. WILL START A FLASH FLOOD WATCH FOR THE WESTERN HALF OF THE CWA WHERE RAIN SHIELD IS PERSISTING (ROUGHLY ALONG AND WEST OF A LLANO TO PEARSALL LINE). IT IS LIKELY THE WATCH WILL NEED RECONFIGURING AS THIS RAIN EVENT EVOLVES. BY MIDWEEK (WEDNESDAY) THE UPPER TROF AXIS IS PROGGED TO SLICE NORTH-SOUTH ALONG I-35 WITH HIGH P.W.`S OVER THE EASTERN THIRD OF THE CWA, KEEPING THE RISK OF FLASH FLOODING RAINS GOING EAST OF I-35. SOIL MOISTURE SHOULD BE REPLENISHED BY LATTER HALF OF NEXT WEEK. THEREFORE, MAX TEMPS WILL HOVER NEAR SEASONAL NORMALS FOR THE WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 88 69 88 70 84 / 80 80 80 60 60 AUSTIN BERGSTROM INTL AIRPORT 87 69 89 68 84 / 80 80 80 60 60 DEL RIO INTL AIRPORT 87 72 86 71 88 / 100 100 70 50 50 SAN ANTONIO INTL AIRPORT 87 72 86 71 85 / 90 90 80 60 60 && .EWX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR THE FOLLOWING COUNTIES: BANDERA...DIMMIT...EDWARDS...FRIO...GILLESPIE...KERR... KINNEY...LLANO...MAVERICK...MEDINA...REAL...UVALDE...VAL VERDE... ZAVALA. && $$ 06/11/PM tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 325 PM MDT SUN AUG 17 2008 .SHORT TERM...TIGHT CYCLONIC CIRCULATION AROUND A VERTICALLY STACKED UPPER LOW NOW OVER NRN TELLER COUNTY HAS CONTINUED TO WRAP LOW AND MID-LEVEL CLOUDS AND SCATTERED THUNDERSTORMS NORTHWESTWARD OVER SOUTH CENTRAL PORTIONS OF THE DENVER/BOULDER WFO COUNTY WARNING AREA. THIS VORTEX IS PROGGED TO TRACK SOUTHEASTWARD OUT OVER THE I-25 URBAN CORRIDOR SOUTH OF THE PALMER DIVIDE BY EARLY THIS EVENING. LAPS AND RUC CAPE...VERTICAL VELOCITY AND STABILITY FIELDS INDICATE A BAND OF MODERATE LIFT AND INSTABILITY ACROSS DOUGLAS... ELBERT AND LINCOLN COUNTIES WHERE MULTI-CELL STORMS HAVE ALREADY ERUPTED. ALTHOUGH STORMS HAVE STRUGGLED TO RETRAIN THEIR UPDRAFTS AS THEY MOVE OFF THE HIGHER TERRAIN. SHOULD SEE THE PRESENT CONVECTION IN DOUGLAS AND ELBERT COUNTIES SHIFT SOUTHEASTWARD NEXT FEW HOURS ALONG AN AXIS OF RAISED INSTABILITY. SOME STORMS MAY BECOME SEVERE DUE TO RELATIVELY STRONG LOW TO MID-LEVEL SHEAR IN THE AREA. FUNNEL CLOUDS...LARGE HAIL...LOCALLY HEAVY RAINFALL AND POSSIBLY A WEAK TORNADO OR TWO ARE POSSIBLE WITH SOME OF THESE STORMS THRU 01Z/MON. MEANWHILE HAVE ALSO SEEN SPOTTY CONVECTION FROM TIME TO TIME OVER THE FRONT RANGE FOOTHILLS AND OUT ACROSS THE NORTHEAST CORNER OF THE STATE...BUT OF LITTLE CONSEQUENCE. AS THE UPPER LOW MOVES OUT ONTO THE SOUTHEASTERN PLAINS...SHOULD SEE A STEADY DECREASE IN CLOUD COVER AND SHOWER/TSTORM COVERAGE DURING THE EVENING HOURS WITH THE 850-500MB FLOW SHIFTING TO A MORE NORTHERLY COMPONENT. HOWEVER... LIGHT BNDRY LAYER FLOW WILL BE HARD PRESSED TO SCOUR OUT SURFACE MOISTURE WITH WIDESPREAD WET/SATURATED SOILS. THEREFORE COULD SEE PATCHY FOG FORMING AFTER MIDNIGHT...ESPLY IN LOW LYING AREAS EAST OF THE I-25 URBAN CORRIDOR. ON MONDAY...WITH THE UPPER LOW SLOWLY MOVING AWAY FROM COLORADO... THE DAY MAY BEGIN WITH A FAIR AMOUNT OF MID-LEVEL CLOUDINESS AND PATCHY FOG AROUND. HOWEVER...AS WINDS ABOVE THE MIXING LAYER TURN TO A MORE NWLY COMPONENT SHOULD SEE DRIER AND AND WARMER AIR SPREADING OVER THE AREA. PRECIPITATION CHANCES LOOK MUCH LOWER ON MONDAY... WITH ONLY ISOLATED/WIDELY SCATTERED AFTERNOON T-STORMS OVER THE MTNS AND FOOTHILLS MAINLY SOUTH OF I-70...AND PALMER DIVIDE. SHOULD SEE SFC TEMPS ACROSS THE CWFA SOME 10-15F WARMER THAN THOSE TODAY. .LONG TERM...MODELS SHOW THE UPPER LOW OVER THE TEXAS PANHANDLE MONDAY EVENING WITH WEAK NORTHERLY FLOW ALOFT FOR THE FORECAST AREA. BY TUESDAY...AN UPPER RIDGE BUILDS IN FROM SOUTHWEST OF THE STATE. NORTHWESTERLY FLOW ALOFT IS PROGGED ON TUESDAY...AND WESTERLY FOR TUESDAY NIGHT INTO WEDNESDAY. IT GOES BACK TO NORTH-NORTHWESTERLY BY WEDNESDAY AFTERNOON AS THE UPPER RIDGE FLATTENS DUE TO A DECENT UPPER TROUGH OVER THE NORTHWESTERN UNITED STATES MOVING EAST. THE SYNOPTIC SCALE ENERGY FOR THE FORECAST AREA IS WEAK DOWNWARD THROUGH THE PERIODS. THE BOUNDARY LAYER FLOW LOOKS TO BE A MIX OF NORMAL DIURNAL TRENDS WITH SOME SOUTHERLY ENHANCEMENT THROWN IN. FOR MOISTURE...MODELS HAVE SOME IN THE LOWER AND MID LEVELS MONDAY EVENING FOR MOST OF THE FORECAST AREA. SAME FOR LATE DAY TUESDAY AND LATE DAY WEDNESDAY. THE NAM SHOWS SOME LOW LEVEL MOISTURE OVER THE PLAINS MONDAY...TUESDAY...AND WEDNESDAY OVERNIGHTS. PRECIPITABLE WATER VALUES ARE IN THE 0.50 TO 1.00 INCH RANGE FROM MONDAY NIGHT THROUGH WEDNESDAY...WITH THE HIGHER VALUES FURTHER EAST ON THE PLAINS. FOR THE MOST PART...DEW POINTS STAY IN THE 50S F OVER THE PLAINS THROUGH ALL THE PERIODS. THE THETA-E AXIS IS OVER SOUTH CENTRAL COLORADO LATE MONDAY. BY LATE DAY TUESDAY IT IS OVER THE WESTERN AND CENTRAL FORECAST AREA. BY LATE DAY WEDNESDAY...IT MIGRATES OVER THE EASTERN FORECAST AREA. THE LAPSE RATE FIELDS ON CROSS SECTIONS SHOW A PRETTY STRONG CAP IN THE MID LEVELS OVER MOST OF THE PLAINS LATE DAY MONDAY AND LATE DAY TUESDAY. IT IS THERE AGAIN WEDNESDAY BUT MAINLY OVER THE FAR EASTERN FORECAST AREA AND IT`S ERODING BY LATE IN THE DAY. THERE IS SOME CAPE MONDAY EVENING OVER THE MOUNTAINS AND FOOTHILLS...BUT IT`S PRETTY MINOR. THERE IS BETTER CAPE OVER ALL THE FORECAST AREA LATE DAY TUESDAY...BEST IN THE MOUNTAINS AND FOOTHILLS...MINOR OUT ON THE PLAINS. BY LATE DAY WEDNESDAY...THERE IS PRETTY DECENT CAPE OVER MOST AREAS. FOR POPS...10%-20% WILL DO...WITH NONE OVER SOME THE PLAINS. FOR TEMPERATURES...TUESDAY`S HIGHS ARE 1.5 - 3.0 C WARMER THAN MONDAY`S. ON WEDNESDAY...HIGHS ARE 1-2 C WARMER THAN TUESDAY`S. FOR THE LATER DAYS...THURSDAY THROUGH SUNDAY...MODELS HAVE THE UPPER RIDGE FLATTENING ON THURSDAY WITH A DECENT UPPER TROUGH MOVING EASTWARD ACROSS THE NORTHERN UNITED STATES. THE TROUGH AXIS MOVES ACROSS THE FORECAST AREA LATE THURSDAY WELL INTO FRIDAY NIGHT. TEMPERATURES COOL OFF FRIDAY AND SATURDAY. MOISTURE INCREASES SOMEWHAT FOR LATE THURSDAY INTO SATURDAY. SUNDAY LOOKS DRY AND WARMER. && .AVIATION...ISOLATED SHOWERS AND THUNDERSTORMS IN THE DENVER METRO AREA THRU 01Z/MONDAY. GUSTY WINDS...LIGHT TO MODERATE RAINFALL BRIEFLY PRODUCING MVFR VSBYS AND CIGS AT THE DENVER INTERNATIONAL AIRPORT. PARTIAL CLEARING OVERNIGHT AS THE UPPER LOW MOVES SOUTHEAST OF THE DENVER METRO AREA. COULD SEE PATCHY FOG FORMING AROUND 10Z IN THE VICINITY OF DIA...ALL OF WHICH SHOULD DISSIPATE WITH CLEARING SKIES BY MID-MORNING. .BOU WATCHES/WARNINGS/ADVISORIES...NONE. && $$ BAKER/RJK co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 320 PM EDT SUN AUG 17 2008 ...WATCHING THE PROGRESS OF TROPICAL STORM FAY CURRENTLY MOVING ALONG THE SOUTH COAST OF CUBA... .SYNOPSIS... 19Z WATER VAPOR AND H4 RUC ANALYSIS REVEALING A FAIRLY MESSY UPPER AIR PATTERN ACROSS NORTH AMERICA. LONGWAVE RIDGING COVERS MUCH OF THE WEST...HOWEVER THE PERSISTENT CUTOFF UPPER LOW CONTINUES TO SPIN IN PLACE OVER COLORADO PINCHING INTO THE EASTERN SIDE OF THIS RIDGE. NO BIG SURPRISE TO FIND LONGWAVE TROUGHING FURTHER TO THE EAST COVERING THE EASTERN THIRD OF THE NATION AS THIS HAS BEEN A SEMI-PERMANENT FEATURE THIS SUMMER. THIS TROUGH CURRENTLY EXTENDS ITS AXIS DOWN THE SPINE OF THE APPALACHIANS TO THE NORTHEAST GULF COAST. PERIODIC PIECES OF MID-LEVEL ENERGY CONTINUE TO ROUND THE BASE OF THIS TROUGH ACROSS OUR FORECAST AREA WITH ONE SHORTWAVE EXITING OFF THE GA COAST EARLIER TODAY AND ANOTHER AND ANOTHER WEAKER SHORTWAVE OVERHEAD AT THIS TIME. AT THE SURFACE...WEAK PRESSURE GRADIENT OVER THE AREA WITH A LIGHT AND VARIABLE MEAN 1000-700MB FLOW. SURFACE WINDS WILL CONTINUE TO BE MORE INFLUENCED BY SEA-BREEZE CIRCULATIONS AND SCT SHOWER/STORM OUTFLOW THAN BY THE GRADIENT. A MIX OF CLOUDS AND SUN ACROSS THE AREA THIS AFTERNOON WITH A BALANCE TIPPED MORE TOWARD THE CLOUDS SIDE. REGIONAL RADARS SHOWING A SCATTERING OF SHOWERS AND STORMS PUSHING WEST TO EAST ACROSS THE AREA. THESE SHOWERS ARE OF THE "POPCORN" VARIETY AND SHOULD BE BRIEF IN DURATION AS THEY COME OVERHEAD. TEMPERATURES IN THE LOWER TO MIDDLE 80S. && SHORT TERM (TONIGHT THROUGH TUESDAY)... MESSY UPPER LEVEL PATTERN CONTINUES OVERHEAD INTO TONIGHT. GLOBAL MODELS SHOWING THE TROUGH BEGINNING TO LIFT OUT A BIT FURTHER TO THE NORTHEAST WITH THE FLOW FLATTENING OUT INTO MONDAY MORNING. SCT EVENING SHOWERS AND STORMS ANTICIPATED TO FADE RAPIDLY AFTER SUNSET WITH THE LOSS OF DIURNAL HEATING...LEAVING PARTLY TO MOSTLY CLOUDY SKIES FOR THE REMAINDER OF THE OVERNIGHT. UPPER LEVEL FLOW BECOMES WEAK DURING MONDAY ACROSS THE SOUTHEAST BETWEEN TROUGHING TO OUR NORTHEAST AND A CUTOFF LOW DROPPING SOUTH FROM COLORADO INTO THE SOUTHERN PLAINS. SURFACE PRESSURE PATTERN ALSO REMAINS VERY WEAK WITH ANOTHER DAY OF LIGHT AND VARIABLE 1000-700MB FLOW. WITH LITTLE IN THE WAY OF SYNOPTIC INFLUENCES WILL FORECAST A POP DISTRIBUTION CLOSE TO CLIMATOLOGY FOR THIS PARTICULAR FLOW REGIME. WILL BE GOING WITH A GENERAL CHANCE POPS RANGE WITH 40 TO 50% COVERAGE FAR NORTH AND 50-55% COVERAGE SOUTH. HIGH TEMPS IN THE MIDDLE 80S TO NEAR 90. GENERAL PATTERN HOLDS INTO MONDAY NIGHT WITH WEAK UPPER LEVEL AND SURFACE FLOW AND NO SIGNIFICANT SYNOPTIC FEATURES OVERHEAD. ONCE AGAIN EVENING SHOWERS/STORMS WILL FADE AFTER SUNSET WITH A MAINLY DRY OVERNIGHT PERIOD. SITUATION WILL BEGIN TO CHANGE LATE MONDAY NIGHT AND MORE INTO TUESDAY MORNING AS THE SURFACE GRADIENT ONCE AGAIN BEGINS TO TIGHTEN BETWEEN HIGH PRESSURE TO OUR NORTH AND TS/HURR FAY TO OUR SOUTH. CURRENT OFFICIAL FORECAST HAS FAY A STRONG TROPICAL STORM OR CAT 1 HURRICANE BY THIS TIME APPROACHING THE SOUTHWEST COAST OF THE FLORIDA PENINSULA. THE STRENGTH AND EXACT POSITION OF FAY WILL DETERMINE JUST HOW MUCH THIS GRADIENT TIGHTENS AND WILL BE OF MOST CONCERN (DURING THIS TIME FRAME) FOR OUR COASTAL WATERS. LOW TEMPERATURES IN THE UPPER 60S TO LOWER 70S...EXCEPT LOWER TO MIDDLE 70S ALONG THE COAST. FORECAST FOR THE DAYLIGHT HOURS OF TUESDAY BEGINS TO BECOME A BIT LOWER CONFIDENCE ALTHOUGH MOST IMPACTS (IF THERE ARE ANY) FROM FAY SHOULD GENERALLY REMAIN TO OUR SOUTH INTO THE EARLY EVENING. MAV POPS ARE GENERALLY IN THE 55 TO 65% LIKELY RANGE FOR TYPICAL SUMMER CONVECTION NOT ASSOCIATED WITH FAY. WILL RUN THIS FORECAST A BIT BELOW THE MAV NUMBERS IN THE 45 TO 55% CHANCE RANGE FOR SCT AFTERNOON SHOWERS AND STORMS UNDER PARTLY TO MOSTLY CLOUDY SKIES. DEPENDING ON THE STRENGTH/POSITION AND ORGANIZATION OF FAY WE COULD EXPERIENCE SOME MINOR CONVECTIVE SUPPRESSION ON THE OUTSKIRTS OF THE CIRCULATION AND HENCE THE SLIGHT DROP OFF FROM THE MAV POPS... HOWEVER WITH THE AMOUNT OF UNCERTAINLY SURROUNDING THIS STORM WILL NOT DEVIATE A WHOLE LOT FROM GUIDANCE. ALSO...ALTHOUGH GENERALLY TEND TO SHY AWAY FROM THE NAM IN ITS LATER HOURS...IT SHOULD BE NOTED THAT THE LATEST RUN CYCLE IS SHOWING SIGNIFICANTLY LESS CONVECTION ON TUESDAY OVER OUR ZONES. HIGH TEMPERATURES IN THE UPPER 80S AND LOWER 90S. && .LONG TERM (TUESDAY NIGHT THROUGH SUNDAY)...LATEST GUIDANCE CONTINUES TO INDICATE A RATHER LARGE SPREAD IN TRACK FORECASTS FOR FAY INTO WEDNESDAY. OFFICIAL FORECAST KEEPS THE STORM TRACK TO OUR EAST AND KEEPS US ON THE WEAKER SIDE OF A WEAKENING TROPICAL STORM. THIS SHOULD KEEP THE IMPACTS TO OUR LOCAL AREA AT A MINIMUM WITH THE GREATEST POTENTIAL FOR SOME GUSTY WINDS AND HEAVY RAIN ACROSS THE EASTERN BIG BEND. HOWEVER...WITH MUCH OF OUR AREA REMAINING IN THE CONE OF UNCERTAINLY...A CLOSE EYE SHOULD BE KEPT TO FUTURE FORECASTS...ESPECIALLY ALONG THE FLORIDA BIG BEND COASTLINE...JUST IN CASE THE TRACK SHIFTS BACK TO THE WEST. AS FAY PROGRESSES NORTHWARD ON WEDNESDAY... TROUGH/SHORT WAVE COMING OUT OF THE ROCKIES INTO THE SOUTHERN PLAINS TODAY WILL BE LOCATED IN THE OK/TX REGION ACCORDING TO GFS. THIS SYSTEM IS A MAJOR PLAYER ON WHAT FAY WILL GO. ACCORDING TO THE GFS...THIS TROUGH GETS CAUGHT UP WITH ANOTHER APPROACHING TROUGH FROM THE PACIFIC NORTHWEST AND RAPIDLY FILLS AND PUSHES NORTHEAST. THE REMNANTS OF FAY REMNANT DOES MUCH THE SAME. THE 00Z EURO HAS ANOTHER SOLUTION. FAY TURNS QUICKLY NORTHEAST AND GETS STUCK FOR A FEW DAYS OFF THE ATLANTIC COAST AS A RIDGE TO THE NORTH BLOCKS ITS PATH. IN OUR AREA...THE GFS SOLUTION HAS AN UPPER RIDGE SETTLING IN BEHIND FAY THROUGH SATURDAY. ON SUNDAY...ANOTHER TROPICAL SYSTEM APPROACHES SOUTH FLORIDA AS A MID LATITUDE TROUGH APPROACHES FROM THE WEST...WHICH MAKES ANOTHER HEAVY WORK SCHEDULE IN OUR NECK OF THE WOODS. THE GFS AND EURO ARE SIMILAR...BUT THE GFS SHOWS MORE A VIGOROUS TROPICAL SYSTEM AS WELL AS MID LATITUDE SYSTEM. && .MARINE... LIGHT GRADIENT WILL KEEP WINDS AND SEAS LOW THROUGH THE DAYLIGHT HOUR ON MONDAY. ATTENTION WILL THEN BEGIN TO SHIFT TO TROPICAL STORM OR HURRICANE FAY IN THE SOUTHEASTERN GULF OF MEXICO. LATEST OFFICIAL TRACK FORECAST BRINGS FAY TO THE EAST OF OUR COASTAL WATERS TUESDAY NIGHT INTO WEDNESDAY KEEPING OUR WINDS GENERALLY OFFSHORE. WILL HAVE TO WATCH THE POTENTIAL FOR SOME GUSTY WINDS AND SWELL OVER THE EASTERN LEGS DURING THIS TIME. HOWEVER...FAY WILL NEED TO BE WATCHED CLOSELY AS A SHIFT IN THE TRACK TO THE WEST WOULD BRINGS THE POTENTIAL FOR HIGHER WINDS AND SEAS TO THE COASTAL WATERS. && .AVIATION... SHOWERS AND ISOLD THUNDERSTORMS ARE AGAIN EXPECTED ESPECIALLY FL TERMINALS WITH TEMPOS FOR TSTMS AND MVFR CIGS/VSBYS ALL TERMINALS... ENDING AROUND 22Z. THEN VFR ON TAP. AFT 09Z...PREVAILING MVFR FOR VSBYS/LIGHT RAIN FOR ALL TERMINALS EXCEPT PERHAPS KPFN AND KABY. AFT 14Z VFR THEN TSTMS COMMENCING AFTER 17Z WITH MVFR CIGS/VSBYS POSSIBLE IN STRONGER STORMS. && .FIRE WEATHER...NO CONCERNS. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 70 89 71 90 73 / 20 50 20 50 40 PANAMA CITY 73 87 74 89 75 / 20 50 20 50 40 DOTHAN 68 88 70 90 71 / 20 50 20 50 30 ALBANY 69 90 70 91 71 / 20 50 20 50 30 VALDOSTA 69 90 70 90 72 / 20 50 20 50 50 CROSS CITY 71 89 71 90 73 / 30 50 20 60 50 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...NONE. GM...NONE. && $$ SYNOPSIS/SHORT TERM/MARINE...MROCZKA AVIATION/FIRE WEATHER...BLOCK LONG TERM...WATSON/MROCZKA fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 217 PM MDT SUN AUG 17 2008 .DISCUSSION... ANOTHER COOL AND WET DAY ACROSS THE TRI-STATE REGION AS A SLOW MOVING LOW TRANSLATES SOUTH OVER THE COLORADO ROCKIES. TEMPERATURES ARE RANGING FROM THE LOWER 60S TO LOWER 70S. RADAR AND SATELLITE IMAGERY CONTINUES TO SHOW MORE RAIN STREAMING INTO THE AREA WITH A FEW EMBEDDED THUNDERSTORMS. COULD SEE UP TO ANOTHER 1/4-1/2 INCH OF RAIN THIS AFTERNOON IF UNDER A MORE INTENSE SHOWER. NAM/GFS KEEPS THE LOW MOVING SOUTH AND SHOULD EVENTUALLY SEE THE ATMOSPHERE BEGIN TO CLEAR OUT BY MONDAY AFTERNOON. A FEW SHOWERS WILL BE POSSIBLE TOMORROW MORNING BUT AM NOT EXPECTING A REPLAY OF TODAY`S PRECIPITATION. CLOUD COVER WILL REMAIN OVER MUCH OF THE FCAST AREA MONDAY...AND WITH THE ABUNDANT MOISTURE IN PLACE...DO NOT EXPECT THE AREA TO WARM UP VERY FAST. HIGHS TOMORROW WILL GENERALLY REMAIN IN THE LOW TO MID 70S OVER EASTERN COLORADO/WESTERN KANSAS AND UPPER 70S TO LOWER 80S OVER GRAHAM AND NORTON COUNTIES. EXPECT TEMPERATURES TO WARM EACH DAY THROUGH FRIDAY AS HIGH PRESSURE SETS IN PLACE AND SOUTHERLY FLOW BRINGS WARMER AIR INTO THE REGION. TEMPERATURES COULD REACH NEAR 90 DEGREES FRIDAY AFTERNOON...BEFORE ANOTHER COOL DOWN OCCURS. ANOTHER PACNW LOW MOVES EAST ACROSS THE NORTHERN STATES FRIDAY INTO SATURDAY...AND A COLD FRONT WILL DRAPE ACROSS THE FORECAST AREA SATURDAY AFTERNOON. WILL NEED TO KEEP AN EYE ON THE TIMING AS IT COULD IMPACT THE DAYS HIGH TEMPERATURES. WITH THE FRONT WILL SEE THE POSSIBILITY FOR MORE SHOWERS AND THUNDERSTORMS TO MOVE INTO THE REGION AND BE COOLER AGAIN THROUGH THE REMAINDER OF THE EXTENDED FCAST. BURTIS && .AVIATION... 1129 AM MDT SUN AUG 17 2008 FOR THE 18Z TAF...UPPER LOW OVER COLORADO CONTINUES TO BRING BOUNDARY LAYER MOISTURE INTO BOTH TERMINALS. WILL CONTINUE TO SEE -RA AT KGLD THROUGH THE LATE EVENING HOURS. RADAR TRENDS SHOWING DEVELOPMENT SOUTH OF KMCK MOVING TO THE NORTH SO HAVE INSERTED TEMPO MVFR -RA GROUP TO COVER. WILL SEE VARIABLE CONDITIONS RANGING FROM VFR TO MVFR AS PRECIP WILL CONTINUE TO IMPACT KGLD. BY TONIGHT...UPPER LOW STARTS TO SLIDE SOUTHEASTWARD INTO THE OK/TX PANHANDLES BRINGING AND END TO PRECIP. RUC13 AND NAM BOTH HINTING AT FORMATION OF LOW STRATUS MONDAY MORNING...PARTICULARLY AT KGLD. HAVE MAINTAINED VFR CIGS FOR NOW BUT THIS WILL NEED TO BE REVISITED FOR THE NEXT TAF CYCLE. FOLTZ && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...FLOOD WATCH UNTIL 6 PM MDT THIS AFTERNOON FOR COZ090>092. && $$ WFO GOODLAND ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 1137 AM MDT SUN AUG 17 2008 .DISCUSSION... 144 AM MDT SUN AUG 17 2008 THE SLOW MOVING UPPER-LEVEL LOW OVER THE CENTRAL ROCKIES IS PROGGED TO ACCELERATE SOUTHEAST INTO SOUTHEAST COLORADO TODAY. THIS WILL LEAD TO ANOTHER WET DAY WEIGHTED ACROSS THE SOUTHWEST ZONES AND TRIED TO SHARPEN THE POP GRADIENT LEAVING ONLY AN ISOLATED MENTION ACROSS THE EASTERN THIRD OF THE FORECAST AREA. STILL SOME CONCERN FOR HEAVY PRECIPITATION NEAR THE COLORADO/KANSAS STATE LINE AREA WITH PWATS IN THE 1.25 INCH RANGE OR 140 PERCENT OF NORMAL/305K WIND STRMLNS/MIXING RATIO INDICATING 10-11 G/KG BEING ADVECTED NORTH ON EASTERN PERIPHERY OF UPPER-LEVEL LOW. WILL KEEP THE FLOOD WATCH INTACT THROUGH TODAY WITH SUCH LOW 1 HR FLASH FLOOD GUIDANCE AND POTENTIAL FOR ANOTHER ROUND OF LOCALLY HEAVY RAIN. INCREASING SUBSIDENCE IS EXPECTED TONIGHT AS THE UPPER-LEVEL LOW MOVES TOWARD THE SOUTHERN PLAINS. KEPT SCATTERED POPS THROUGH 06Z WEIGHTED IN THE SOUTH/SOUTHWEST WITH NO MENTION PLANNED THEREAFTER. SOME CONCERN FOR DENSE FOG DEVELOPING WITH WET GROUND/LIGHT SOUTHERLY WINDS ON WESTERN PERIPHERY OF SFC LOW AND INCREASING SUBSIDENCE SUPPORTING DIMINISHING CLOUDS/RADIATIONAL COOLING. MONDAY-TUESDAY...MID/UPPER RIDGE COVERING MUCH OF THE WEST WILL TRANSLATE EAST INTO THE CENTRAL GREAT BASIN/ROCKIES BRINGING MORE TYPICAL WEATHER TO THE CENTRAL HIGH PLAINS. THE PRIMARY CHANGE FROM THE PREVIOUS FORECAST WAS TO REMOVE POPS AND WARM TEMPERATURES A LITTLE MORE AGGRESSIVELY IN THE NORTHEAST ZONES. SEASONABLE TEMPERATURES IN THE UPPER 80S ARE ANTICIPATED. DAYS 4 THROUGH 7...NO CHANGES. MCGUIRE && .AVIATION... 1129 AM MDT SUN AUG 17 2008 FOR THE 18Z TAF...UPPER LOW OVER COLORADO CONTINUES TO BRING BOUNDARY LAYER MOISTURE INTO BOTH TERMINALS. WILL CONTINUE TO SEE -RA AT KGLD THROUGH THE LATE EVENING HOURS. RADAR TRENDS SHOWING DEVELOPMENT SOUTH OF KMCK MOVING TO THE NORTH SO HAVE INSERTED TEMPO MVFR -RA GROUP TO COVER. WILL SEE VARIABLE CONDITIONS RANGING FROM VFR TO MVFR AS PRECIP WILL CONTINUE TO IMPACT KGLD. BY TONIGHT...UPPER LOW STARTS TO SLIDE SOUTHEASTWARD INTO THE OK/TX PANHANDLES BRINGING AND END TO PRECIP. RUC13 AND NAM BOTH HINTING AT FORMATION OF LOW STRATUS MONDAY MORNING...PARTICULARLY AT KGLD. HAVE MAINTAINED VFR CIGS FOR NOW BUT THIS WILL NEED TO BE REVISITED FOR THE NEXT TAF CYCLE. FOLTZ && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...FLOOD WATCH UNTIL 6 PM MDT THIS AFTERNOON FOR COZ090>092. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 418 PM EDT SUN AUG 17 2008 .SYNOPSIS... WATER VAPOR LOOP/RUC ANALYSIS REVEALS A BROAD RIDGE FM WEST COAST INTO CNTRL PLAINS WHILE A TROUGH LINGERS OVER ERN CANADA INTO NEW ENGLAND AND MID ATLANTIC STATES. NW FLOW BETWEEN THESE LARGE SCALE FEATURES BRINGING ANOTHER SHORTWAVE AND ASSOC FRONTAL SYSTEM FROM NRN ONTARIO SOUTH TOWARD THE UPR GREAT LAKES. MODELS INDICATE THIS FRONTAL SYSTEM WILL MOVE ACROSS THE UPR GREAT LAKES LATE TONIGHT AND EARLY MONDAY. SO FAR...RADAR LOOP SHOWS ONLY SOME ISOLD SHRA OVER LUCE COUNTY THIS AFTERNOON WHERE THERE APPEARS TO BE SOME CONVERGENCE ALONG LAKE BREEZE BOUNDARIES AND HIGHER DEWPOINTS IN THE LOWER 60S CONTRIBUTING TO SBCAPES IN EXCESS OF 1000/KG. MID-LVL RIDGING APPEARS TO HAVE REST OF CWA FAIRLY WELL CAPPED. && .SHORT TERM (TONIGHT AND MONDAY)... AS SHORTWAVE OVR ONTARIO DIVES NE OF LAKE SUPERIOR...FRONTAL SYSTEM MOVES ACROSS THE FCST AREA LATE TONIGHT AND EARLY MONDAY. PCPN CHCS ARE UNCERTAIN AT BEST WITH THIS SYSTEM WHICH IS REFLECTED IN VERY LOW POPS IN MODEL MOS GUIDANCE. THE PROBLEM IS THAT THE BEST ISENTROPIC LIFT AND STEEPEST MID-LVL LAPSES ARE WELL EAST OF FCST AREA WHEN FRONT ARRIVES LATE TONIGHT. ALSO GIVEN LATE ARRIVAL WITH FRONT...MUCAPES ONLY 100-200 J/KG. WITH ABOVE MENTIONED UNFAVORABLE FACTORS FOR PCPN...HAVE DECIDED TO TRIM BACK POPS TO SLIGHT CHC LATE TONIGHT OVER LAKE SUPERIOR AND THE NRN TIER COUNTIES WITH 30 PCT OVER LUCE COUNTY. WENT WITH JUST SLIGHT CHC FOR MON MORNING ACROSS THE CWA AS FRONT MOVES ACROSS AREA AND THEN LEFT A LINGERING SLIGHT CHC OVER MNM COUNTY IN THE AFTERNOON. SW WINDS AND HIGH TD WILL ALLOW TEMPS TO STAY GENERALLY ABV MOS GUIDANCE. KEPT GOING FCST OF LOW TO MID 60S WITH WARMEST TEMPS FOR DOWNSLOPING AREAS ALONG LAKE SUPERIOR. LOWERED HIGH TEMPS SOME FOR MON AS WINDS SHIFT NE BY LATE MORNING/EARLY AFTERNOON. DID NOT GO TOO COLD FOR MON AS 850 MB THERMAL TROF LAGS BEHIND SFC COLD FRONT BUT DID LOWER TEMPS TO LOWER 70S OVER NRN TIER AND UPPER 70S TO AROUND 80F SOUTH. .LONG TERM (MON NIGHT THROUGH NEXT SUN)... MON NIGHT THROUGH WED...QUIET PERIOD IN STORE FOR UPPER MI AS HIGH PRESSURE DROPS DOWN OUT OF CENTRAL CANADA INTO THE AREA BEHIND MONDAYS COLD FRONT. FOR MONDAY NIGHT...DRY AIR CONTINUES TO FLOW INTO THE CWA WITH PRECIPITABLE WATER VALUES DROPPING TO AROUND 0.60 OF AN INCH BY 06Z (ABOUT 65 PCT OF NORMAL). THEREFORE A COOL NIGHT IS EXPECTED...ESPECIALLY WITH WINDS DROPPING OFF AFTER MIDNIGHT INLAND. LOWERED LOWS TOWARDS THE COOLER MET AND 00Z MEX COOP GUIDANCE. IN ADDITION...GIVEN THE COOL TEMPERATURES AND THE WARMER LAKES...ADDED PATCHY FOG TO AREAS WITH LIGHT WINDS. WIND FLOW IS GENERALLY EAST TO SE ON TUE AS THE HIGH CENTERS ITSELF OVER EASTERN LAKE SUPERIOR. THIS MEANS COOL READINGS ALONG LAKE SUPERIOR...THOUGH NOT ALL TOO COOL SINCE THE NEARSHORE AREA OF LAKE SUPERIOR IS RELATIVELY WARM THIS TIME OF YEAR. 850MB TEMPS IN THE 9-12C RANGE (WARMEST WEST) SUPPORTS HIGHS MAINLY IN THE 70S...WITH READINGS IN THE UPPER 60S NEAR LAKE SUPERIOR. TUE NIGHT IS A BIT TRICKY WITH THE FORECAST AS RETURN FLOW BEGINS TO SET UP...PARTICULARLY ACROSS THE WEST HALF. IN FACT...MODELS SHOW WHAT APPEARS TO BE AN ACCAS DECK DEVELOPING OVER THE WEST HALF AFTER MIDNIGHT. NEITHER THE NAM/GFS PRODUCE ANY PCPN...WHICH SEEMS REASONABLE SINCE THE BOUNDARY LAYER IS QUITE DRY AND THE AIRMASS ABOVE THE ACCAS DECK IS CAPPED. SO NO POPS NEEDED. THESE MID CLOUDS COMBINED WITH A SOUTHERLY BREEZE WILL HELP TO HOLD TEMPS UP OUT WEST...BUT CLEAR SKIES AND LIGHT WINDS THROUGH MUCH OF THE NIGHT OUT EAST MEANS ANOTHER COOL NIGHT. WENT BELOW MOST OF MOS GUIDANCE...CLOSER TO THE 00Z MEX COOP GUIDANCE WHICH INDICATES SOME OF THE COLD SPOTS OF LUCE COUNTY DROPPING INTO THE MID 40S. GIVEN THE COOL READINGS...AGAIN ADDED SOME PATCHY FOG. OTHER THAN THE MID CLOUD ON WED WHICH SHOULD GRADUALLY DISSIPATE THROUGH THE DAY...THERE SHOULD BE PLENTY OF SUN. WITH 850MB TEMPS CLIMBING TO 14-17C BY 18Z...HIGHS SHOULD BE 5-10 DEGREES F WARMER THAN TUE. COOLEST READINGS ON WED EXPECTED ON LAKE MI AND THE EAST SIDE OF THE KEWEENAW PENINSULA WHERE ONSHORE FLOW OCCURS. WED NIGHT THROUGH SUN...MODELS CONTINUE TO BE IN VERY GOOD AGREEMENT ON THE UPPER LEVEL PATTERN...SHOWING THE RIDGING OVER THE CWA WED EVENING TO GRADUALLY SHIFT TO THE EAST...WHILE A TROUGH OVER THE PACIFIC NW MOVES INTO THE GREAT LAKES LATE IN THE WEEKEND. THE 06Z GFS REMAINS THE MOST AMPLIFIED WITH THE TROUGH COMPARED TO THE 00Z ECMWF/UKMET...BUT WITH REGARD TO THE TROUGH AXIS AND THE COLD FRONT ASSOCIATED WITH THE TROUGH...THE 06Z GFS IS NEARLY IDENTICAL TO THE 00Z ECMWF. SINCE THE 00Z ECMWF LOOKS FAIRLY SIMILAR TO ITS 12Z PREDECESSOR...AND HAS SOME CONTINUITY TO THE PREVIOUS FORECAST... HAVE DECIDED TO FOLLOW IT FOR THE EXTENDED. HPC HAS ALSO PREFERRED THE 00Z ECMWF. IT SHOULD BE NOTED THAT THERE STILL REMAINS SOME SPREAD IN THE 00Z GFS ENSEMBLES ON THE SPEED OF THE UPPER TROUGH...WITH SOME MEMBERS FASTER AND OTHER SLOWER THAN THE 00Z ECMWF...BUT THE 00Z ECMWF IS PROBABLY A GOOD COMPROMISE. NEW 12Z ECMWF IS JUST SLIGHTLY FASTER THAN ITS 00Z RUN...WHILE THE 12Z GFS IS GENERALLY THE SAME. WILL MAINTAIN A DRY FORECAST FOR WED NIGHT THROUGH THU...DESPITE A SHRTWV MOVING ACROSS...SINCE THE WIND FLOW COMES OUT OF THE DRY HIGH PRESSURE AREA THAT MOVED TO THE EAST OF OUR AREA ON WED. DEWPOINTS ACTUALLY SHOULD MIX OUT INTO THE 50S...AND WITH 850MB TEMPS CLIMBING TO 16-18C BY 00Z FRI...THE AIR MAY BE CAPPED ANYWAY. WILL CONTINUE THE DRY FORECAST THROUGH FRI AS WELL...DESPITE THE 06Z GFS TRYING TO BRING UP WHAT APPEARS TO BE CONVECTIVELY INDUCED SHRTWVS FROM LOUISIANA. FRI MAY TURN OUT TO BE A VERY WARM DAY IF THE ECMWF DOES PAN OUT...AS IT SHOWS 850MB TEMPS AROUND 20C WITH INCREASING SOUTH/SOUTHWEST WINDS. GFS WAS A BIT COOLER...WHICH COULD BE A RESULT OF THE CONVECTIVELY INDUCED SHRTWVS. RIGHT ENTRANCE REGION UPPER JET SUPPORT...COLD FRONT AND HEIGHT FALLS APPROACH THE CWA FRI NIGHT ASSOCIATED WITH THE UPPER TROUGH...AND SOME CONVECTION SHOULD AT LEAST MOVE INTO THE WEST HALF OF UPPER MI. THEREFORE ADDING CHANCE POPS TO THE WESTERN CWA. THIS CONVECTION MAY WEAKEN SATURDAY MORNING...BUT MORE THAN LIKELY REDEVELOP DURING THE AFTERNOON AS THE FRONT ENCOUNTERS A LAKE BREEZE OFF LAKE MICHIGAN. LOOKS LIKE DECENT MID-LEVEL FLOW WILL BE IN PLACE...SO MAY NEED TO WATCH FOR SEVERE WEATHER. IF WE ARE LUCKY...THIS FRONT COULD BRING A DECENT AMOUNT OF RAIN TO THE AREA...SINCE PRECIPITABLE WATER VALUES ARE PROGGED AROUND 1.75 INCHES OR 200 PCT OF NORMAL. DRY SLOT MOVES IN LATER SATURDAY...BUT WILL BE REPLACED BY LOW CLOUDS FOR SAT NIGHT/SUN MORNING AS THE UPPER TROUGH AND COLDER AIR MOVES IN. IN FACT...THE 00Z ECMWF/06Z GFS SHOW 850MB TEMPS DROPPING TO 4C ON SUNDAY. THIS LOOKS A BIT TOO COOL...BUT READINGS OF 6-9C MAY NOT BE OUT OF THE QUESTION. NEW 12Z ECMWF/GFS HAVE WARMED TO THESE READINGS. THEREFORE...THE WAY IT LOOKS RIGHT NOW...EXPECT QUITE A BIT OF CHANGE IN TEMPS FROM FRI TO SUN AS READINGS GO FROM ABOVE NORMAL TO BELOW NORMAL. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... EXPECT VFR CONDITIONS TO CONTINUE INTO THE EARLY OVERNIGHT HOURS LATE TONIGHT WITH A RATHER DRY WESTERLY FLOW OVER THE AREA. A COLD FRONT WILL DROP SOUTHWARD INTO UPPER MICHIGAN OVERNIGHT TONIGHT AND MAY BE ACCOMPANIED BY ISOLATED SHOWERS AND THUNDERSTORMS...BUT PROBABILITY IS NOT HIGH ENOUGH TO INCLUDE AT EITHER TAF SITE. UPSLOPE NE FLOW DEVELOPING BEHIND THE FRONT COULD BRING SOME HIGH MVFR CLOUDS INTO KSAW AFTER SUNRISE ON MONDAY. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... COLD FRONT DROPPING DOWN FROM ONTARIO SHOULD CAUSE WSW WINDS TO INCREASE ON LAKE SUPERIOR TO UP TO 25 KNOTS TONIGHT. EXPECT A RAPID WIND SHIFT TO THE NORTH AND THEN NE MONDAY MORNING AS THE FRONT DROPS SOUTH. WIND SPEEDS MAY APPROACH 25 KT OVER SOUTHERN LAKE SUPERIOR. WINDS WILL DIMINISH TO AT OR BELOW 20 KT MON NIGHT AND STAY THAT WAY THROUGH TUE EVENING AS HIGH PRESSURE MOVES SOUTHEAST ACROSS EASTERN LAKE SUPERIOR. AS THIS HIGH DRIFTS TO THE EAST TUE NIGHT...SOUTHERLY WINDS WILL INCREASE TO UP TO 25 KT...THEN DIMINISH TO BELOW 20 KT ON WED AS THE MARINE LAYER REESTABLISHES ITSELF. SOUTHERLY WINDS INCREASE AGAIN WED NIGHT TO UP TO 25 KT THROUGH THU...THEN EVEN HIGHER...UP TO 30 KT...ON FRI AS A COLD FRONT APPROACHES FROM THE PLAINS. COLD FRONT EXPECTED TO MOVE INTO WESTERN LAKE SUPERIOR FRI NIGHT WITH A WIND SHIFT TO THE WEST...BUT STILL BREEZY BEHIND IT. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS/SHORT TERM...JV LONG TERM...AJ AVIATION...JV MARINE...AJ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 338 PM EDT SUN AUG 17 2008 .DISCUSSION...NRN MICHIGAN SITTING WITHIN WEAK MID LEVEL RIDGING AND SFC HIGH PRESSURE THIS AFTERNOON. WARM TEMPERATURES AND FAIRLY HIGH LOW LEVEL MOISTURE (SFC DEWPOINTS IN THE UPPER 50S TO MID 60S) YIELDING MUCAPE VALUES UP NEAR 1000 J/KG OVER NE LOWER MICHIGAN (PER RUC ANALYSIS). TOOK AWHILE...BUT ISOLATED SHOWERS/TSTMS FINALLY GETTING GOING OVER PORTIONS OF THE CWA IN THE LAST HOUR OR SO. LACKLUSTER LAPSE RATES ABOVE THE CBL (DUE TO ONGOING MID LEVEL WARM ADVECTION) MAY BE AT LEAST PARTIALLY TO BLAME FOR THE SLOW START TO MOIST CONVECTION. NONETHELESS...EVERYTHING I HAVE LOOKED AT OVER THE LAST FEW HOURS STILL SUGGESTS THAT FURTHER HEATING AND LOW LEVEL CONVERGENCE SHOULD BE ENOUGH FOR AT LEAST ISOLATED TO SCT SHOWERS AND STORMS LATE THIS AFTERNOON INTO THE EARLY EVENING HOURS. SO...PLAN ON CARRYING POPS ACCORDINGLY ACROSS NE LOWER AND A PORTION OF EASTERN UPPER MICHIGAN...BASICALLY WHERE CU FIELD IS THE MOST PRONOUNCED. BEYOND THAT...HEALTHY CU FIELD ALSO NOTED OVER NRN WISCONSIN AND WESTERN UPPER MICHIGAN THIS AFTERNOON. MAY YET SEE SOME SHOWER/TSTM ACTIVITY DEVELOP THERE PARTICULARLY ALONG ANY LAKE MICHIGAN MARINE BOUNDARIES. IF SO...ANY OF THIS ACTIVITY MAY ULTIMATELY DRIFT ACROSS THE LAKE INTO NW LOWER MICHIGAN AT SOME POINT THIS EVENING. BUT THIS AREA APPEARS A BIT MORE CAPPED ALOFT THAN US AND GIVEN THE LACK OF ACTION THUS FAR PLAN ON LEAVING OUT POPS ACROSS NW LOWER MICHIGAN FOR NOW. AS FAR AS SEVERE WEATHER IS CONCERNED...RELATIVE LIGHT WIND FIELDS (30 KNOTS OR LESS THROUGH 500 MB) WILL KEEP STORM ORGANIZATION AT BAY ALTHOUGH A FAIRLY DEEP MIXED LAYER (INVERTED-V LOOK) AND RESPECTABLE CAPE PROFILE WILL SUPPORT SUB-SEVERE THUNDERSTORM GUSTS AND SMALL HAIL THROUGH EARLY EVENING. LATER ON...APPROACHING COLD FRONT SLIPPING OUT OF CANADA MAY BRING ANOTHER LOW END CHANCE FOR SHOWERS/STORMS TO UPPER MICHIGAN TOWARD MORNING. ADAM MONDAY AND MONDAY NIGHT...AFOREMENTIONED FRONTAL BOUNDARY WILL SAG SOUTH ACROSS THE REGION DURING THE DAY. WITH DAYTIME HEATING...THIS WILL SET THE STAGE FOR ADDITIONAL SCATTERED CONVECTION. NAM/GFS ARE IN REASONABLY GOOD AGREEMENT THAT E-W ORIENTED FRONT WILL MOVE FROM ERN UPPER MI AT 1200 UTC TO SRN LOWER MI BY 00Z MONDAY EVENING. MID LEVEL SHORTWAVE DROPPING SE THROUGH ONTARIO WILL SUPPLY A RATHER MODEST SHOT OF LARGE-SCALE LIFT -- MAINLY ACROSS FAR NRN AREAS. MEANWHILE...8H THERMAL AXIS (WITH TEMPS AROUND +18C)...WILL LIKELY KEEP ATMOSPHERE CAPPED OFF UNTIL MIDDAY ACROSS SRN AREAS (PER MODEL SOUNDINGS). STILL...WITH TEMPS WELL INTO THE 80S AND SFC DEW POINTS IN THE LOWER 60S...EXPECT 500 TO LOCALLY 1000 J/KG MLCAPE BY MID AFTERNOON ALONG AND SOUTH OF M-32 CORRIDOR. UPSHOT...SCATTERED SHOWERS/STORMS WILL IMPACT AREAS OF N OF TVC-APN UNTIL MIDDAY...AND ACROSS ALL BUT ERN UPPER DURING THE AFTERNOON. SEVERE WEATHER NOT LIKELY...WITH 0-6 KM BULK SHEAR AROUND 20 KTS...AND FREEZING LEVELS AROUND 13 KFT. AS FRONT SAGS SOUTH...EXPECT SPOTTY CONVECTION TO LINGER DURING THE EARLY EVENING HOURS ACROSS SOUTHERN AREAS. NE WINDS AND DRIER AIR WILL FILTER INTO REGION DURING THE REST OF THE NIGHT BEHIND FRONT. PER MODEL SOUNDINGS AND NAM GUIDANCE...HAVE INCREASED CLOUD COVER A BIT ACROSS PARTS OF NE LOWER LATE MON NIGHT INTO EARLY TUES -- DUE TO SHALLOW LAKE PROCESSES. WITH LAKE HURON WATER TEMPS NEAR +20C AND 925 MB TEMPS NEAR +9C...COUPLED WITH TERRAIN INFLUENCES...SOME SHALLOW LAKE CLOUDS SEEM POSSIBLE. TUESDAY...HIGH PRESSURE N OF THE SAULT WILL DRIFT TO VICINITY OF LAKE HURON BY LATE AFTERNOON. ASIDE FROM SAID LAKE CLOUDS EARLY OVER NE AREAS...EXPECT DRY AIR ADVECTION AND MIXING TO PRODUCE PARTLY TO MOSTLY SUNNY SKIES ALL AREAS BY NOON. IT/LL BE A BIT COOLER...WITH MIXING TO NEAR 850 MB SUPPORTING HIGHS AROUND 70 E UPPER AND NE LOWER...AND IN THE 70S ELSEWHERE. WEDNESDAY...DEEP LAYER RIDGING WILL RESULT IN A GREAT DAY...WITH PLENTY OF SUNSHINE AND WARM TEMPERATURES. 8H TEMPS IN THE TEENS WILL SUPPORT HIGHS AROUND 80 AREAWIDE. EXTENDED PERIOD...THU THRU SUN...GFS/ECMWF/ENSEMBLES AGREE THAT DRY WEATHER WILL LINGER INTO AT LEAST THUR...WITH RIDGING AT THE SURFACE AND ALOFT OVER THE NERN U.S.. RETURN FLOW ON BACK SIDE OF RIDGE WILL BEGIN TO ADVECT INCREASING MOISTURE INTO THE GREAT LAKES...AND BIG QUESTION IS WHEN INSTABILITY/FORCING WILL BE SUFFICIENT FOR CONVECTION LATE IN THE WEEK. GFS BRINGS A MID LEVEL IMPULSE NE INTO REGION FRI...THOUGH GFS ENSEMBLE DATA DOES NOT SUPPORT THIS SCENARIO. ECMWF IS ALSO MUCH SLOWER WITH IMPULSE...SUGGESTING THAT CONVECTION WILL HOLD OFF UNTIL SAT. THIS SLOWER SOLUTION NOW SEEMS MOST PLAUSIBLE...BASED LARGELY ON IMPACT OF TROPICAL SYSTEM OVER SERN U.S. WHICH MAY EFFECTIVELY SLOW SYSTEM MOVEMENT. SO...HAVE OPTED TO KEEP DRY WEATHER GOING INTO FRI...WITH SHOWERS/STORMS POSSIBLE SAT/SUN. TEMPTED TO DRY THINGS OUT FOR SUNDAY...WITH BOTH GFS AND ECMWF BRINGING A FRONT THRU EARLY IN THE DAY. HOWEVER...WITH ENSEMBLE DATA SUPPORTING A SLOWER PROGRESSION (CONSISTENT WITH TROPICAL INFLUENCE) WILL TENTATIVELY KEEP RISK OF CONVECTION GOING INTO SUNDAY. SEASONABLY WARM LATE SUMMER TEMPERATURES EXPECTED THROUGH THE PERIOD...WITH HIGHS FROM 80 TO 85 THU/FRI/SAT...AND GENERALLY 75 TO 80 SUN. SMITH && .AVIATION...ISSUED AT 134 PM. WITH CONTINUED HEATING AND DESTABILIZATION...JUST WAITING FOR SHOWERS/THUNDER TO DEVELOP OVER NORTHEAST LOWER MICHIGAN... POTENTIALLY IMPACTING APN UNTIL EARLY EVENING. OTHERWISE...VFR CONDITIONS ANTICIPATED THROUGH TONIGHT. ON MONDAY...COLD FRONT DROPPING THROUGH NRN MICHIGAN EXPECTED TO BRING BKN MID CLOUD (VFR) TO TVC/PLN/APN. WILL BE A RISK FOR SHOWERS/STORMS BUT MAINLY DURING MONDAY AFTERNOON. ADAM && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. LH...NONE. LS...NONE. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 342 PM EDT SUN AUG 17 2008 .SYNOPSIS... A STATIONARY FRONT LYING ACROSS THE GULF COAST STATES REGION WILL SLOWLY MOVE BACK TO THE NORTH INTO SOUTH CAROLINA BY TUESDAY AS HIGH PRESSURE STARTS TO BUILD SOUTH INTO THE AREA FROM THE NORTHEAST. THE HIGH WILL KEEP THE FRONT TO OUR SOUTH AND WILL ALSO HAVE SOME INFLUENCE ON THE FUTURE MOVEMENT OF TROPICAL STORM FAY. FAY IS FORECAST TO MOVE INTO THE SOUTHEAST OVER GEORGIA...STALL AND THEN DISSIPATE DURING THE COURSE OF THE WEEK. THE REMNANTS OF FAY COULD RESULT IN SOME PRECIPITATION ACROSS THE REGION BY MID TO LATE WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM SUNDAY...LARGE AREA OF SHOWERS AND THUNDERSTORMS HAVE TRANSLATED EASTWARD THROUGH THIS AFTERNOON. GREATEST PCP AMOUNTS RUNNING FROM GEORGETOWN WILLIAMSBURG COUNTIES NORTH THROUGH COLUMBUS AND HORRY COUNTIES. SEA BREEZE WAS HOLDING OFF ANY PCP FROM THE COAST...BUT LOOKS LIKE IT MAY START AFFECTING THE COASTAL AREAS WITHIN THE NEXT HOUR OR SO. CONVECTION HAS LINED UP NICELY WITH IMPULSES MOVING THROUGH THE MID LEVEL FLOW THIS AFTERNOON. LATEST RUC SHOWING SHORTWAVE ENERGY RIDING AROUND THE MID LEVEL TROUGH THROUGH TONIGHT AND FINALLY PUSHING EAST BY MORNING. LEFT SOME LOW CHC POPS OVERNIGHT TO ACCOUNT FOR THIS...BUT MAINLY ONLY SLIGHT CHC ALONG THE COAST BY MORNING. DEEP LAYER MOISTURE HOLDING THIS AFTERNOON WITH PCP WATER VALUES ABOVE 1.75 MOST AREAS. CAPE VALUES EXCEEDING 1000 J/KG MAINLY JUST ALONG THE COAST AND SOUTH OF AREA THROUGH THIS EVENING. LOOKS LIKE SOME MID TO UPPER LEVEL DRY AIR WILL MAKES ITS WAY INTO AREA AS SHORTWAVE FINALLY PUSHES EASTWARD OVERNIGHT. COUNTING ON FINALLY GETTING RID OF THE SOLID DECK OF AC/CIRRUS BY MORNING. OVERALL EXPECT SHOWERS/TSTMS TO DIMINISH THROUGH MIDNIGHT OVER MOST AREAS EXCEPT COASTAL SECTIONS WHERE CHC OF PCP WILL LINGER INTO THE MORNING. DEPENDING ON HOW MUCH CLEARING WE GET OVERNIGHT WILL MAKE THE DIFFERENCE IN TERMS OF FOG AND LOW TEMPS. FOR NOW...MENTIONED SOME PATCHY FOG IN FORECAST MAINLY INLAND AREAS AND TO A LESSER EXTENT OVER COASTAL AREAS WHERE CLOUDS AND PCP MAY LINGER LONGER. && .SHORT TERM /MONDAY MORNING THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...AS HIGH PRESSURE STARTS TO BUILD INTO THE REGION WILL WILL START TO SEE SOME DRIER AIR WORKING INTO THE AREA. SOME LOW LEVEL MOISTURE DOES REMAIN OVER THE REGION ON MONDAY AND A WEAK UPPER LEVEL DISTURBANCE WILL MOVE INTO THE AREA WHICH COULD KICK OFF A SOME SCATTERED SHOWERS DURING THE AFTERNOON SO I WILL MENTION AROUND 30 POPS ACROSS THE CWA. TEMPS WILL BE ABOUT A COUPLE OF DEGREES BELOW NORMAL...MID 80S ALONG THE COASTAL AREAS WITH UPPER 80S TO AROUND 90 INLAND. WILL KEEP WITH MOSTLY CLEAR TO PC SKIES FOR TUESDAY AS ENOUGH RIDGING BUILDS INTO THE AREA TO SUPPRESS MUCH IN THE WAY OF CLOUDS ACROSS THE AREA. STALLED FRONTAL BOUNDARY WILL REMAIN SOUTH OF SC AND ENOUGH MID TO UPPER LEVEL DRY AIR MOVES INTO THE REGION TO KEEP US DRY THROUGHOUT THE AFTERNOON SO I WILL DROP THE SLIGHT CHANCE OF POPS THAT WE HAD IN THE FORECAST WITH TEMPS AROUND THE SAME AS MONDAY MAYBE A DEGREE OR SO HIGHER..NOT EXPECTING TOO MUCH OF AN INCREASE CONSIDERING THE SUNNY SKIES SINCE WE WILL HAVE A NE FLOW AROUND THE HIGH. MOISTURE STARTS TO INCREASE ACROSS THE AREA LATER TUESDAY AS ANY INFLUENCES FROM FAY START TO MOVE NORTHWARD. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 3 PM...THE EXTENDED IS ALL ABOUT THE TRACK OF TS FAY AND ITS POTENTIAL IMPACT ON OUR SENSIBLE WX. LATEST NHC FORECAST TAKES THE CENTER FROM NORTHERN FLORIDA ON WEDNESDAY MORNING...UP INTO THE WESTERN CAROLINAS THURSDAY NIGHT AND FRIDAY. WITH SFC AND UPPER RIDGING MAKING IT TO THE MID-ATLANTIC COAST BY WEDNESDAY...A DEEP E-SE FETCH WILL SET UP OVER THE CAROLINA COAST AND COULD SET THE STAGE FOR FAIRLY SIGNIFICANT PRECIP ACROSS PART OR ALL OF THE ILM CWA. NOT REAL CONFIDENT IN THE QPF JUST YET AS IT REMAINS TO BE SEEN WHAT FAY WILL LOOK LIKE BY THEN...AND HOW BROAD OF A MOISTURE PLUME CAN BE PULLED INTO THE AREA. WILL CARRY MID TO HIGH CHANCE POPS FROM WEDNESDAY ALL THE WAY INTO FRIDAY...BUT THE TIMING AND PLACEMENT WILL NEED TO BE REFINED ON LATER SHIFTS. IF THE NHC TRACK WORKS OUT THEN THE FRIDAY POP MAY BE OVERDONE AS THE REMNANT LOW WILL BE NORTH OF US BY THEN...BUT WITH THE SLOWER PROGRESS ADVERTISED BY BOTH GFS AND ECMWF...A HIGHER THAN CLIMO POP IS STILL JUSTIFIED AT THIS POINT. TEMPS WILL BE SLIGHTLY BELOW CLIMO BY DAY AND ABOVE BY NIGHT...AS CLOUDS AND PRECIP WILL LIMIT DIURNAL RANGES. TOUGH TO SAY WHAT LIES BEYOND FOR NEXT WEEKEND...AS ALL THE MEDIUM-RANGE MODELS ARE HANGING ON TO THE TROPICAL LOW MUCH LONGER THAN THE OFFICIAL NHC FORECAST. THIS ZFP ISSUANCE WILL REFLECT CONDITIONS NEAR CLIMO...WITH SILENT/SLIGHT CHANCE POPS. && .AVIATION /19Z SUNDAY THROUGH FRIDAY/... LINE OF SHOWERS AND THUNDERSTORMS MOVING THROUGH FLO AND LBT AT TAF TIME WILL CONTINUE TO MOVE OFF TO THE NORTHEAST CLEARING ANY TSTMS FROM INLAND TAF SITES BY 21Z. THIS LINE WILL TRANSLATE EASTWARD AFFECTING CRE AND MYR THIS AFTERNOON AND POSSIBLY ILM AFTER 20Z. ONCE THE IMPULSE IN THE MID LEVELS WHICH TRIGGERED THIS ACTIVITY MOVES THROUGH...SHWRS/TSTMS WILL DIMINISH BY LATER THIS EVENING. EXPECT MID TO HIGH CLOUDS TO HANG AROUND THROUGH MIDNIGHT...DISSIPATING AS SOME DRIER AIR MAKES ITS WAY INTO THE MID TO UPPER LEVELS OF THE ATMOSPHERE THROUGH DAYBREAK. COASTAL TAFS WILL SEE THE CHC OF SHWRS THROUGH THE MORNING HOURS. WITH PLENTY OF MOISTURE HOLDING ON OVERNIGHT EXPECT ANOTHER NIGHT OF MVFR/VFR IN FOG AND LOW STRATUS AT COASTAL TAF SITES WITH IFR/LIFR AT FLO AND LBT MAINLY BETWEEN 08Z-12Z. OUTLOOK THOUGH FRIDAY...DRIEST DAYS WILL BE MONDAY AND TUESDAY WITH JUST SOME AFTERNOON SHWR/TSTMS POSSIBLE. THE EARLIEST IMPACT THAT T.S. FAY WOULD HAVE ACROSS THE TERMINALS WILL BE LATE WEDNESDAY INTO THURSDAY. THE EFFECTS OF FAY SHOULD DIMINISH THROUGH FRIDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM SUNDAY...SHORTWAVE MOVING NE ACROSS LOCAL WATERS THROUGH TONIGHT WILL HELP PROMOTE SOME SHWRS/TSTMS OVERNIGHT. AS FOR WINDS AND SEAS EXPECT LIGHT NE TO E WINDS TONIGHT WITH SEAS 3 FT OR LESS. && SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...EAST TO SOUTHEAST WINDS ON MONDAY WILL BE NEAR 10 KTS NEAR SHORE AND ABOUT 10 TO 15 KTS OFFSHORE KEEPING SEAS IN THE 1 TO 3 FOOT RANGE THROUGHOUT THE DAY. LIGHT NORTHEAST WINDS ON TUESDAY MORNING WILL SHIFT AROUND BACK TO THE SOUTHEAST BY AFTERNOON WITH THE SAME SPEEDS AS MONDAY SO AGAIN WILL KEEP THE SEAS AROUND 1 TO 3 FEET ACROSS THE WATERS. DONT SEE ANY INFLUENCE YET OF FAY THROUGH THE SHORT TERM PERIOD. WILL KEEP CHANCE POPS ACROSS THE WATERS ON MONDAY AS UPPER LEVEL DISTURBANCE MOVES ACROSS THE AREA BUT WILL DROP POPS ON TUESDAY AND HOLD OFF ANY MENTION OF SHOWERS OR THUNDERSTORMS UNTIL LATER IN THE PERIOD AS MOISTURE FROM FAY STARTS TO MOVE NORTHWARD INTO THE REGION. && LONG TERM /WEDNESDAY THROUGH THURSDAY/... AS OF 3 PM...THIS PORTION OF THE FORECAST HINGES ON THE TRACK OF TS FAY. LATEST NHC TRACK REMAINS OVER LAND...SO WIND SPEEDS SHOULD BE QUITE MODEST. WILL KEEP A E-SE DIRECTION WITH SPEEDS GENERALLY AROUND 15 KT WED- THU. WITH NHC ADVERTISING A REMNANT LOW BY FRIDAY...EXPECT A DIMINISHING TREND. WHAT IS LESS CERTAIN IS WHETHER WE WILL SEE A VEERING TO SOUTH AS THE LOW GETS NORTH OF OUR LATITUDE...OR IF WE STAY MORE E-SE WITH THE STRONG RIDGING ALONG 40N. SEAS WILL DEPEND HEAVILY ON HOW MUCH OF THE WIND FIELD FROM FAY IS OVER THE ATLANTIC. HAVE STUCK CLOSE TO THE VARIOUS FLAVORS OF WNA WAVE GUIDANCE...WITH SEAS HOLDING 4-5 FT THRU MOST OF THE PERIOD. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...MAC NEAR TERM...RGZ SHORT TERM...MAC LONG TERM...RAS AVIATION...RGZ MARINE... nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX 1132 AM CDT SUN AUG 17 2008 .UPDATE... SCATTERED SHOWERS ARE EXPECTED TODAY IN WAKE OF SATURDAYS WEATHER SYSTEMS...THAT BROUGHT A FEW AREAS OF LOCALLY HEAVY RAIN TO SOUTH CENTRAL TEXAS. THERE WILL BE A CHANCE FOR SHOWERS OR THUNDERSTORMS TODAY...AND A FEW LOCATIONS COULD SEE LOCALLY HEAVY RAIN AGAIN... THAT CAUSES SOME LOCALIZED STREET FLOODING. SOILS CONTINUE TO BE DRY...AS THE AREA CONTINUES TO BE IN A DROUGHT. ANY ADDITIONAL RAIN TODAY COULD CAUSE SOME LOCALIZED STREET FLOODING ON POORLY DRAINED ROADS AND LOW WATER CROSSINGS...HOWEVER WIDESPREAD FLOODING IS NOT EXPECTED AT THIS TIME FOR TODAY FROM 12Z TO 16Z TRENDS AND 12Z FORECAST SOLUTIONS. A BIG CHANCE IS COMING THIS WEEK. A HEAVY RAIN EVENT IS EXPECTED TO DEVELOP MONDAY THROUGH WEDNESDAY...BRINGING MORE WIDESPREAD WETTING AND LOCALLY HEAVY RAINS. AS THE LOW MOVES OVER NORTH AND CENTRAL TEXAS MONDAY AND TUESDAY...THIS RAIN MAKING WEATHER SYSTEM WILL BECOME NEARLY STATIONARY THROUGH WEDNESDAY AND WILL HAVE PLENTY OF MOISTURE TO SUPPORT A HEAVY RAIN EVENT. THIS HEAVY RAIN EVENT COULD BEGIN AS EARLY AS MONDAY AND CONTINUE THROUGH WEDNESDAY. RAINFALL AMOUNTS OF 2 TO 6 INCHES ARE POSSIBLE...AND HEAVIER RAINFALL AMOUNTS COULD DEVELOP MONDAY THROUGH WEDNESDAY IN PLACES WHERE STORMS BECOME STATIONARY OR CONTINUE TO TRACK ACROSS THE SAME LOCATION. AS A RESULT...A FLASH FLOOD WATCH WILL LIKELY BE ISSUED ON MONDAY FOR MONDAY THROUGH WEDNESDAY THAT WILL ENCOMPASS ALL OF SOUTH CENTRAL TEXAS AND THE HILL COUNTRY. FOR NOW INDICATED THIS RAINFALL PATTERN IN A SPECIAL WEATHER STATEMENT. BY THURSDAY AN APPROACHING AND MORE PROGRESSIVE TROF OVER THE NW U.S. IS FORECAST TO CAUSE HEIGHT FIELD FURTHER EAST TO LIFT WEAK LOW NNE AND FLATTEN OUT THE 700 TO 300 HPA TROF SOME OVER S. CNTRL TX THURSDAY. THIS WILL KEEP RAIN CHANCES GOING FOR THURSDAY. ON FRIDAY THE WEAK TROF WILL DRIFT SLIGHTLY EAST...SHIFTING THE CHANCE OF RAIN TO THE EAST...FOR THE EASTERN THIRD OF SOUTH CENTRAL TEXAS. THIS SHOWER ACTIVITY IS FORECAST TO DIMINISH FRIDAY EVENING. A WEAK SOUTHWEST TO NORTHEAST ALIGNED 700 TO 300 HPA TROF OVER THE EAST PART OF THE AREA FRIDAY IS FORECAST TO DRIFT FURTHER EAST SATURDAY AND SUNDAY...AS A WEAK RIDGE FROM 700 TO 300 HPA FORMS OVER THE AREA FROM THE WEST. THIS WILL BRING PARTLY CLOUDY...WARM AND HUMID DAYS FOR SATURDAY AND SUNDAY OF NEXT WEEKEND. THE WEAK RIDGE MAY NOT LAST TOO LONG...AS IN THE MID PART OF THE WEEK OF AUG. 24TH TO AUG. 30TH... ANOTHER S/W TROF IS EXPECTED TO MOVE IN FROM THE NORTH AND CAUSE A CHANCE FOR SHOWERS FOR THE MIDDLE PART OF THAT WEEK. IN THE MEANTIME...SCATTERED SHOWERS ARE EXPECTED TODAY...WITH SOME LOCALLY HEAVY RAIN POSSIBLE...FOLLOWED BY MORE WIDESPREAD RAINS FROM SHOWERS AND THUNDERSTORMS MONDAY THROUGH WEDNESDAY. && .PREV DISCUSSION... /ISSUED 627 AM CDT SUN AUG 17 2008/ AVIATION... A MIX OF MVFR AND VFR CIGS/VSBYS FORECAST THROUGH THE TAF PERIOD WITH SHOWERS AND THUNDERSTORMS...ALTHOUGH BRIEF PERIODS OF IFR CONDITIONS CAN NOT BE RULED-OUT WITH THE STRONGER STORMS. THUNDERSTORM COVERAGE WILL INCREASE THIS AFTERNOON NEAR I-35 TERMINALS. PREV DISCUSSION... /ISSUED 315 AM CDT SUN AUG 17 2008/ DISCUSSION... INVERTED SFC TROF ANALYZED FROM LAREDO TO HONDO TO LLANO AT MIDNIGHT. A CONVERGENCE WAS ALSO ANALYZED FROM JUST NORTH OF LAREDO EAST TO JUST NORTH OF CORPUS CHRISTI. THE INTERSECTION IS KEEPING RAIN GOING ACROSS MAVERICK AND DIMMIT COUNTIES. THE RUC PICKS UP ON THE CONVERGENT BOUNDARY AND HAS IT STATIONARY THIS MORNING. MODELS NOT DOING TOO GOOD WITH SURFACE FEATURES BECAUSE OF THE MANY OUTFLOW BOUNDARIES. HOWEVER, THE UPPER LEVELS ARE ALL INITIALIZED WELL WITH 00Z UPPER AIR PLOTS. BETTER ORGANIZED RAIN WILL SHAPE UP TODAY WITH THE 700MB TROF MOVING SOUTHEAST TOWARD THE RIO GRANDE. THE RIO GRANDE REGION IS EXPECTED TO RECEIVE EXCESSIVE RAIN TODAY LEADING TO LOCALIZED FLOODING. THE 700MB TROF IS PROGGED TO DRIFT EASTWARD ACROSS THE CWA OVER THE NEXT 3 DAYS. WITH THE TROPICAL AIR OVER US, LOCALLY HEAVY RAIN AND THE POSSIBILITY OF FLASH FLOODING WILL BE WITH US THROUGH AT LEAST TUESDAY. WILL START A FLASH FLOOD WATCH FOR THE WESTERN HALF OF THE CWA WHERE RAIN SHIELD IS PERSISTING (ROUGHLY ALONG AND WEST OF A LLANO TO PEARSALL LINE). IT IS LIKELY THE WATCH WILL NEED RECONFIGURING AS THIS RAIN EVENT EVOLVES. BY MIDWEEK (WEDNESDAY) THE UPPER TROF AXIS IS PROGGED TO SLICE NORTH-SOUTH ALONG I-35 WITH HIGH P.W.`S OVER THE EASTERN THIRD OF THE CWA, KEEPING THE RISK OF FLASH FLOODING RAINS GOING EAST OF I-35. SOIL MOISTURE SHOULD BE REPLENISHED BY LATTER HALF OF NEXT WEEK. THEREFORE, MAX TEMPS WILL HOVER NEAR SEASONAL NORMALS FOR THE WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 88 69 88 70 84 / 80 80 80 60 60 AUSTIN BERGSTROM INTL AIRPORT 87 69 89 68 84 / 80 80 80 60 60 DEL RIO INTL AIRPORT 87 72 86 71 88 / 100 100 70 50 50 SAN ANTONIO INTL AIRPORT 87 72 86 71 85 / 90 90 80 60 60 && .EWX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 08/13/PM tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 303 PM CDT SUN AUG 17 2008 .SHORT TERM...THROUGH WEDNESDAY CONCERNS THROUGH THE SHORT TERM REMAIN THE SAME...SMALL RAIN CHANCES MAINLY MONDAY AFTN INTO TUE AFTN AS WEAK BACK DOOR FRONT SLIPS SOUTHWEST INTO MN/WI. PERIOD TO REMAIN WARM...WITH SLOWLY INCREASING HUMIDITY...BUT WARMEST TEMPERATURES LIKELY ONLY TOPPING OUT IN THE MID-UPPER 80S. CURRENTLY...ANOTHER LARGE CUMULUS FIELD OVER MN/WI/IA TODAY AS STRONG WARMING ON NORTH SIDE OF PLAINS HIGH PRESSURE SYSTEM CONTINUES LOW LEVEL WARM ADVECTION ON WESTERLY FLOW. THIS HAS ALLOWED CONVECTIVE TEMP TO BE REACHED...BUT WITH PWATS RUNNING 1.0-1.2 INCHES...ABOUT NORMAL FOR MID AUGUST...AND LITTLE TO NO CONVERGENCE...SHRA HAVE BEEN VERY ISOLD OVER ERN WI WHERE SFC DWPTS HAVE POOLED INTO MID 60S. ELSEWHERE...MIXING ONCE AGAIN HAS TAKEN HOLD OF THE SHALLOW BOUNDARY LAYER MOISTURE AND TAKEN DWPTS BACK INTO THE 50S MOST AREAS OF MN/IA. STRONG SHORTWAVE TROUGH EVIDENT IN GOES WATER VAPOR OVER ND WAS REALLY BEGINNING TO DEAMPLIFY AS MODELS HAD SUGGESTED IT WOULD. MORE COMPLEX WAVE ENERGY UPSTREAM IN MANITOBA/ONTARIO WILL REASSERT THE NERN CONUS TROUGH...AND IS SENDING A RATHER MARKED FRONTAL BOUNDARY SOUTH INTO THESE PROVINCES OF CANADA...THOUGH LITTLE PCPN NOTED AT THIS TIME. COMPACT/POTENT CUTOFF LOW CONTINUES TO SPIN OVER CO. STRONG TROUGH OUT OVER THE PACIFIC /SEE EXTENDED DISCUSSION FOR ITS IMPLICATIONS TO FORECAST/. TONIGHT...AS HAS BEEN THE SIGNAL IN RECENT SREF RUNS AND OCCASIONAL GFS/NAM-WRF DATASETS...ISOLD SHRA/TSRA WILL REMAIN POSSIBLE OUT OF AGITATED CUMULUS FIELD OVER CNTL/ERN WISCONSIN. INITIATION COULD OCCUR AS FAR WEST AS MAUSTON OR RICHLAND CENTER...BUT PREVAILING NWLY FLOW ALOFT WOULD TAKE ANY ACTIVITY QUICKLY OUT OF FORECAST AREA...SO WILL GO DRY OVERNIGHT. EXPECT STRONG ND WAVE TO CONTINUE TO DEAMPLIFY CONSIDERABLY AS IT CROSSES AREA AFTER MIDNIGHT...AND WITH LITTLE SURFACE REFLECTION OR MOISTURE TRANSPORT...DON/T THINK ANY PCPN THREAT FROM THIS. LATEST BATCH OF NAM-WRF...NSSL-WRF...AND RUC13 ALL SUGGEST LITTLE NO PCPN THREAT OUT OF CUMULUS FIELD IN ARX FORECAST AREA. MONDAY-TUESDAY...COMPLEX WAVE ENERGY MENTIONED ABOVE DRIVES BACK DOOR COLD FRONT /SWWRD MOVING TAIL END OF SYNOPTIC COLD FRONT/ TO SINK VERY SLOWLY SOUTHWEST INTO CNTL WISCONSIN/ECNTL MN MON AFTN WITH RATHER STRONG CONVERGENCE AND LOCALIZED MOISTURE POOLING WHICH WILL BUMP MLCAPES INTO 1000 J/KG RANGE AT PEAK HEATING. FEEL PRETTY GOOD THAT SCT-BKN BAND OF STORMS WILL LIGHT UP ON FRONT IN EARLY AFTN AND SINK SOUTHWEST INTO THE I-94 CORRIDOR AT PEAK HEATING. DEEP SHEAR IS VERY LOW...AND CAPE NOT ROBUST...SO AT THE VERY WORST...AN ISOLD DMG GUST/LARGE HAIL THREAT BUT SREF CALIBRATED PROBS FOR SEVERE /17.03Z AND 17.09Z/ SHOWING ALMOST NIL PROBABILITIES...IMPLYING A VERY ISOLD THREAT. BIGGEST THREAT MAY ACTUALLY BE LOCALLY HEAVY RAIN GIVEN WEAK WINDS ALOFT AND SLOW CELL MOVEMENT. THESE STORMS LOOK TO RIDE PRIMARILY ON FRONTAL CONVERGENCE/INSTABILITY IN DIURNAL CYCLE...SO EXPECT A QUICK WEAKENING TOWARD 02Z...AND MODELS/PROBABILITIES AGREE WITH NO TRANSPORT/ADVECTION TO KEEP STORMS GOING INTO THE OVERNIGHT. ON TUESDAY...AS RIDGE BUILDS IN QUICKLY ALOFT...BOUNDARY QUICKLY UNDERGOES FRONTOLYSIS. IN FACT...CONVERGENCE WEAKENS MARKEDLY INTO TUES AFTN. WINDS ALOFT EXTREMELY WEAK. BY AFTN...ONLY LINGERING AFFECT OF FRONT MAY BE LOCALLY HIGH MOISTURE/INSTABILITY AXIS WHICH MAY CONVECT IN ISOLD FASHION IF CONVECT TEMPS CAN BE REACHED. MODELS CONTINUE TO SPECKLE VERY SMALL PCPN BLOBS ON WEST SIDE OF MS RIVER WHERE THE CONVERGENCE MAY BE ENOUGH TO SPARK SOMETHING. IF SOMETHING DOES DEVELOP...HEAVY RAIN THREAT WITH ALMOST NO FLOW ALOFT TO MOVE THE STORMS. MAINTAINED THE RAIN CHANCES MONDAY/MONDAY EVE IN THE DATABASE...AND ENHANCED THEM A LITTLE MON AFTN OVER CNTL WISCONSIN NEAR FRONT. DID NOT INTRO RAIN THREAT FOR TUES GIVEN VERY WEAK SIGNALS OVERALL. WEDNESDAY QUIET AS REMNANT FRONT DECAYS COMPLETELY AND LIFTS NORTH OUT OF AREA AS RIDGE ALOFT MAINTAINS WARM CONDITIONS. .LONG TERM...THURSDAY THROUGH SUNDAY THIS PERIOD MARKED BY STRONG FRONTAL PASSAGE FRI NIGHT/SATURDAY USHERING CHANGE OF AIRMASS FOR END OF NEXT WEEKEND. HIGH CONFIDENCE THERE...BUT LOWER CONFIDENCE ON THUR/FRI WITH CONTINUED SUBTLE DIFFERENCES IN HANDLING OF OLD/DECAYING UPPER LOW OVER OKLAHOMA. 17.12Z ECMWF/GEM/GEFS MEANS CONTINUE TO SUGGEST THAT REMNANT CUTOFF LOW WILL SINK FAR ENOUGH SOUTH THAT BY THE TIME IT BEGINS TO BE ABSORBED INTO STRONGER FLOW AHEAD OF SRN CANADA SHORTWAVE TROUGH...IT WILL SHEAR NORTHEASTWARD IN WEAKENED STATE AND MAY BRING SOME SMALL RAIN THREATS TO MAINLY IL/WI THURS NIGHT. THIS WILL...HOWEVER...SERVE TO INCREASE THE DEEP MOISTURE WITH PWAT OVER 1.5 INCHES SURGING NORTH AND BEING IN PLACE ON FRIDAY...AND THE RECENT DETERMINISTIC GFS/ECMWF RUNS SUGGEST THIS MOISTURE COUPLED WITH INCREASING DYNAMICS AND APPROACHING FRONT ON FRIDAY WILL ALLOW SHOWERS AND STORMS TO DEVELOP ON FRIDAY WELL OUT AHEAD OF THE COLD FRONT. THIS LOOKS REASONABLE. THERE WAS GOOD WFO CONSENSUS AND COLLABORATION TO REMOVE RAIN THREATS THURSDAY...AND FOCUS SMALLER THREATS ON THURSDAY NIGHT. MAINTAINED RAIN CHANCES FRI THROUGH SAT AS THE COLD FRONT MARCHES THROUGH. USING PURELY DETERMINISTIC GFS RUNS...SEVERE THREAT FRI/FRI NIGHT NOT LOOKING OVERLY HIGH GIVEN DEEP BUT WEAK SLY FLOW /LITTLE DEEP SHEAR/ AND MODEST CAPE...THANKS TO RATHER MOIST SOUNDINGS...NOT TO MENTION FRONTAL SURGE MAINLY OVERNIGHT. STRONG WIND FIELDS LAG THE FRONT. THINK SATURDAY HAS A GOOD CHANCE OF BEING LARGELY DRY THANKS TO RAPID PROGRESSION OF HEIGHT FALLS/FRONT ACROSS THE NRN CONUS. THIS A VERY WELL AGREED UPON SOLUTION IN MODELS/ENSEMBLES...BUT WILL HOLD ONTO SATURDAY RAIN CHANCES IN CASE FRONT SLOWS UP A BIT. AIRMASS FOR SUNDAY INTO EARLY NEXT WEEK STARTING TO LOOK FALLISH...WITH POTENTIAL FOR WIDESPREAD DWPTS IN THE 40S SUN/MON GIVEN MOISTURE CONTENT BEHIND THE FRONT. UPPER RIDGE BUILDS BACK INTO THE WRN/CNTL CONUS SUNDAY INTO NEXT WEEK WITH PERHAPS ANOTHER LONG SPELL OF QUIET WEATHER. BINAU && .AVIATION... VFR CONDITIONS LOOK TO BE DOMINANT THROUGH THE MIDDLE PART OF THE NEW WEEK...AS A SFC HIGHS CONTINUE TO INFLUENCE THE UPPER MISSISSIPPI RIVER VALLEY. HOWEVER...A WEAK SURFACE BOUNDARY...ASSOCIATED WITH UPPER LEVEL ENERGY MOVING ACROSS SOUTHERN CANADA...COULD BRING SOME AFT/EVENING SHRA/TS CHANCES MON AND TUES. THE BOUNDARY LOOKS TO EXTEND WEST-EAST ACROSS MN/WI...AND WILL HAVE AROUND 1000-1500 J/KG OF MUCAPE AND 850-700 MB LAPSE RATES NEAR 8 C/KM TO WORK WITH. THESE CHANCES WILL LIKELY STAY WELL EAST THOUGH...ACROSS EASTERN WI. EXPECT THE WEST/SOUTHWEST WINDS TO BECOME MORE EASTERLY ON TUES AS THE BOUNDARY SINKS SOUTH OF KRST/KLSE. RIECK && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 159 PM CDT SUN AUG 17 2008 .SHORT TERM... ISOLATED SHOWERS DEVELOPING OVER SOUTH CENTRAL WISCONSIN. ONE REACHED 52 DBZ BEFORE WEAKENING. RUC ANALYSIS INDICATES MLCAPE RISING TO NEAR 2000 J/KG WITH LI/S FALLING TO -4. FORECAST SOUNDING INDICATE MIXING SHOULD REDUCE DEW POINTS SLIGHTLY DURING THE AFTERNOON. MID LEVELS FAIRLY DRY ABOVE WEAK CAP AROUND 600 MB...SO DEEP CONVECTION SHOULD BE LIMITED WITH ENTRAINMENT. HOWEVER ISOLATED THUNDERSTORM IS POSSIBLE IF A STORM MAKES IT ABOVE THE CAP WITH UPPER LEVEL LAPSE RATES FAIRLY STEEP. LATEST LOCAL 4KM WRF BASED OFF 15Z LAPS SHOW ONLY SMALL ISOLATED AND RELATIVE WEAK SHOWERS THIS AFTERNOON AND EARLY EVENING...WITH CRAS ONLY HAVING A FEW GRID POINTS WITH A HUNDREDTH OR SO. 12Z WRF BASED OF GFS AND 12Z NAM SHOWS NO THUNDERSTORMS OR SHOWERS. EVEN WITH THE WEST SURFACE WINDS 1622Z MODIS SHOWS WARM UPPER 60 DEGREE LAKE MICHIGAN TEMPS NEAR SHORE...WITH NO COOLER UPWELLING SEEN. WOULD HAVE THOUGHT TEMPS WOULD HAVE BEEN COOLER...BUT WINDS ARE WEAK. WEAK UPSTREAM SHORTWAVE AND ASSOCIATED RELATIVELY WEAK UPPER SPEED MAX TO REACH THE FORECAST AREA MAINLY MONDAY...WITH MAIN SHORTWAVE NORTHEAST OF THE LAKE SUPERIOR AREA. TRAILING WEAK COLD FRONT/WIND SHIFT WOULD BE THE FOCUS FOR ANY THUNDERSTORM DEVELOPMENT. HOWEVER LOW AND MID LEVELS BECOME A LITTLE DRIER...SO WILL NOT MENTION ANY PRECIPITATION...WITH POPS IN THE 10 TO 14 PCT RANGE. MAIN EFFECT WILL BE A MORE NORTHEAST SURFACE WIND MONDAY NIGHT...WITH EASTERLY FLOW TUESDAY. THIS WILL BRING SOMEWHAT COOLER TEMPERATURES...MAINLY NEAR LAKE MICHIGAN. .LONG TERM... BOTH 12Z GFS AND 00Z ECMWF GRADUALLY BUILD UPPER RIDGE OVER THE UPPER MISSISSIPPI VALLEY AND WESTERN GREAT LAKES TUESDAY...AND OVER THE GREAT LAKES WEDNESDAY. WEAK SHORTWAVE APPROACHES THURSDAY...WITH REMNANTS OF CENTRAL ROCKIES UPPER LOW AROUND EASTERN OKLAHOMA. APPEARS SHORTWAVE IN NORTHERN STREAM WILL BE TOO FAR NORTHWEST TO AFFECT THE FORECAST AREA...WHILE DECAYING UPPER LOW WILL BE TOO FAR SOUTHWEST. AS A RESULT WILL REMOVE THE CHANCE OF THUNDERSTORMS THURSDAY. NOW NO QPF ON 12Z GFS/00Z ECMWF/OR 06Z DGEX. GFS PICKS UP THE REMNANTS OF THE UPPER LOW AND MOVES IT TOWARD THE MID MISSISSIPPI VALLEY THURSDAY NIGHT AND FRIDAY. GFS NOW LEANING TOWARD THE SLOWER AND WEAKER ECMWF ON THIS. HOWEVER GFS STILL HAS A SOMEWHAT STRONGER SHORTWAVE FRIDAY NIGHT AHEAD OF THE MAIN SHORTWAVE EXITING THE NORTHWEST U.S. ECMWF NOW CLOSER TO GFS IN BREAKING DOWN THE UPPER RIDGE AS NORTHWEST U.S. SHORTWAVE MOVES TO NORTHERN MINNESOTA BY SATURDAY. WILL GRADUALLY INCREASE POPS FRIDAY AND SATURDAY AHEAD OF SHORTWAVE...WITH INCREASING MOISTURE AND INSTABILITY WITH SOUTH WINDS ON BACKSIDE OF THE DEPARTING SURFACE HIGH...AND LOW MOVING INTO THE NORTHERN PLAINS. && .AVIATION... VFR EXPECTED THRU PERIOD. TCU AND ISOLATED STORMS WILL DIMINISH QUICKLY AFTER SUNSET WITH CLEARING SKIES OVERNIGHT. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ SHORT/LONG TERM...06/HENTZ AVIATION/MARINE...18/BORGHOFF wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 1249 PM CDT SUN AUG 17 2008 .UPDATE...INTRODUCED ISOLATED THUNDERSTORMS FOR THIS AFTERNOON FOR ALL OF SOUTHERN WISCONSIN. TCU NOW EVIDENT OVER CENTRAL AND PORTIONS OF SOUTH CENTRAL WI. RUC ANALYSIS INDICATES MLCAPE RISING TO NEAR 2000 J/KG WITH LI/S FALLING TO -4 AS SHORT WAVE TRACKS TOWARD THE AREA THIS AFTERNOON. GOOD DIRECTIONAL SHEAR PRESENT AS WELL...HOWEVER SPEED SHEAR WILL BE A LIMITING FACTOR FOR ANY SEVERE POTENTIAL. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ UPDATE...BORGHOFF wi