AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SACRAMENTO CA 220 PM PDT WED APR 25 2001 MOST TEMPS RUNNING WARMER THAN YESTERDAY AS ANTICIPATED. APPEARS THE SAC RECORD OF 92F WILL BE TIED OR BROKEN BY 530 PM. WINDS ARE LIGHT...EVEN DELTA WITH FLAT SFO-SAC GRADIENT. CUMULUS HAVE DEVELOPED OVER THE BURNEY BASIN/SOUTHERN CASCADES AND A FEW IN THE COASTAL RANGE. LAPS CAPES ARE SHOWING 400-1000J/KG IN THIS REGION. SHORT TERM FORECAST CONCERN WILL BE WHETHER ANY TCU CAN BECOME CB'S TODAY. ANY STORMS SHOULD BE ISOLATED. ETA SHOWS PW'S REACHING NEAR .80-IN NEAR REDDING THIS EVENING. 12Z ETA SOUNDINGS SHOW THE LFC TO BE A HIGH 10 TO 12KFT WITH LARGE CINS BELOW THIS. 500-MB LI'S ARE -1 TO -2 AND 850-500-MB LAPSE RATES ARE 7.5C/KM. MODELS CONT TO SHOW AN AXIS OF HIGHER PW'S TO ADVECT INTO NORCAL LATE TODAY AHEAD OF A WEAK VORT AXIS. AVN IS FURTHER NORTH WITH ITS TRACK AND WATER VAPOR SHOWS IT MOVING INTO THE NORTH COAST ATTM. ELEVATED CAPE VALUES ON THE ETA REMAIN HIGH (200-400 J/KG) SO HIGH TERRAIN WILL BE NEEDED TO TRIGGER/LIFT. LATEST 18Z RUC SHOWS VALUES PROGGED TO 1300 J/KG THIS EVENING WITH NO CINS IN THE LASSEN AREA. 00Z-06Z THU QVEC CONVERGENCE MAY ADD THE NEEDED DESTABILIZATION. SOUTHWEST FLOW EXIST TODAY BUT IS RATHER WEAK. STILL THINK THERE IS A CHANCE OF A COUPLE THUNDERSTORMS TO DEVELOP IN THE SOUTHERN CASCADES OR FAR NRN SIERNEV. BEST INSTABILITY SHIFTS TO OUR SRN SIERNEV ON THURSDAY WHILE MID LEVEL SOUTHWEST FLOW INCREASES SLIGHTLY OVER THE NRN MTNS WITH WEAK SOUTHWEST FLOW OVER THE SIERNEV KEEPING BUILDUPS NEAR THE CREST. ANOTHER SHORT WAVE IS PROGGED TO MOVE INLAND THURSDAY AFTERNOON TAKING A TRACK OVER THE SJ VALLEY INTO THE SRN SIERRA. WILL PUT ISOLD TSRA FOR SIERRA CREST AND COORD WITH RENO. AVN SHOWS 200-400 J/KG CAPE FROM I-80 CREST SOUTHWARD AND ETA LI'S ARE -2. ANOTHER WARM DAY ON THURSDAY THOUGH MARINE INFLUENCE SHOULD BE FELT IN THE DELTA AND MAYBE SAC AREA AS DEPTH INCREASES. H85 TEMPS LOWER 1-2C OVER THE REGION. HIGH CLOUDS NOW SEEN ALONG 130W WILL MOVE INTO THE STATE. SFO-SAC GRADIENT INCREASES TO 2.5-MB BY 00Z FRIDAY LEADING TO A DELTA BREEZE THURSDAY NIGHT. GRADIENT INCREASES TO 3.5-MB FRIDAY AND H85 TEMPS DROP 4-6C. GOOD DELTA BREEZE SHOULD CONT INTO FRIDAY NIGHT WITH A STRONGER SHORT WAVE REACHING THE OREGON BORDER AND DROPPING A WEAK COLD FRONT INTO NORCAL ON FRIDAY. PRECIP WITH THIS FRONT LOOKS MARGINAL FOR OUR CWA WITH ONLY DYNAMICS IN FAR NORCAL. INCREASING H85-5 SOUTHWEST FLOW FRIDAY AS WELL. GENERAL CONSENSUS OF MODELS SHOWS THE BEST CHANCE OF SHOWERS TO BE SATURDAY WITH A PROGRESSIVE SHORT WAVE DIGGING THRU NORCAL AND ASSOCIATED H7-5 QVEC CONVERGENCE. H85 TEMPS LOWERING TO 6C AND MARINE INFLUENCE WILL MAKE FOR THE COOLEST DAY OF THE FORECAST PACKAGE. 12Z UKMET AND NOGAPS ARE TRENDING A NORTHWARD SHIFT TO THE STORM TRACK SIMILAR TO THE 12Z/24 ECMWF. BASED ON MODEL TRENDS AND THE TIME OF YEAR WILL LEAN TO DRIER/WARMER SOLUTIONS AND ONLY MENTION SHOWERS MONDAY (MIGHT BE SUNDAY NIGHT) AND TUESDAY FOR THE FAR NORTH AND THIS LOOKS MARGINAL. SUNDAY/MONDAY COULD HAVE A NICE WARMING TREND. WILL REMOVE SHOWERS THAT WERE PLACED IN THE CENTRAL SAC VLY. PROGRESSIVE FLOW IS SEEN MON-WED IN THE PACNW BUT SYSTEMS MAY BE TOO FAR NORTH TO AFFECT OUR CWA. .STO...NONE. BLU UB 052/066 049/060 041 650-0 RBL UU 052/084 053/078 048 65000 SAC UU 053/082 052/075 050 65000 TARDY ca AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SACRAMENTO CA 905 AM PDT WED APR 25 2001 MORNING SOUNDINGS FROM AIR RESOURCE BOARD SHOW ABOUT 5F OF WARMING AT 5000FT...THIS WILL RESULT IN WARMER MAX TEMPS THIS AFTERNOON AS WE MIX OUT. H85 TEMPS ON KOAK SOUNDING ARE 1C WARMER AND MARINE LAYER DEEPENED A TAD BUT ONLY AROUND 700 FEET. OUR RECORD OF 92F SET IN 1987 IS SOFT AND WE SHOULD GET CLOSE TO IT BY LATE IN THE DAY. ACV-SFO GRADIENT IS DOWN 2-MB WHILE THE SFO-SAC REMAINS FLAT WITH THERMAL TROF OVER THE AREA. SKIES ARE CLEAR EVERYWHERE. SHORT TERM CONCERN FOCUSES MORE ON MOIST CONVECTIVE CHANCES. AT THIS TIME PROBABLY WILL NOT UPDATE TO REINTRODUCE BUT MONITOR AND IF ACTIVITY DOES DEVELOP IT CAN GO IN THE 3PM PACKAGE. ANY STORMS SHOULD BE ISOLATED. YESTERDAY SAW LOTS OF MODERATE TO ALMOST TOWERING CUMULUS ALONG THE SRN CASCADES/NRN SIERNEV CREST. WHAT HAS CHANGED TODAY IS THAT PW'S ARE OBSERVED UP TO .40-IN AT KRNO WHICH IS A MODEST INCREASE FROM .36-IN YESTERDAY. HOWEVER SLIGHT INCREASES IN MOISTURE WILL INCREASE INSTABILITY. THIS SOUNDING IS CAPPED AROUND 14000FT. MEDFORD SOUNDING PW'S ARE 0.74-IN UP FROM 0.62-IN 24-H AGO. ETA SHOWS PW'S REACHING NEAR .80-IN NEAR REDDING. THIS IS A MOIST AIRMASS THOUGH NOT AS MOIST AT MONSOON SEASON. THERE IS ALSO A CAP ON MFD SOUNDING BUT IT IS MORE UNSTABLE THAN YESTERDAY. 12Z ETA AND RUC SOUNDINGS SHOW THE LFC TO BE A HIGH 10 TO 12KFT WITH LARGE CINS BELOW THIS. 500-MB LI'S ARE -1 TO -2 AND 850-500-MB LAPSE RATES ARE 7.5C/KM. MODELS CONT TO SHOW AN AXIS OF HIGHER PW'S TO ADVECT INTO NORCAL THIS AFTERNOON AHEAD OF A WEAK VORT AXIS. AVN IS FURTHER NORTH WITH ITS TRACK AND WATER VAPOR SHOWS CLUES OF ITS EXISTENCE NEAR 125W/35N MOVING NE. ELEVATED CAPE VALUES ON THE ETA REMAIN HIGH (200-400 J/KG) SO HIGH TERRAIN WILL BE NEEDED TO TRIGGER/LIFT. 00Z-06Z THU QVEC CONVERGENCE MAY ADD THE NEEDED DESTABILIZATION. SOUTHWEST FLOW EXIST TODAY BUT IS RATHER WEAK. STILL THINK THERE IS A CHANCE OF A COUPLE THUNDERSTORMS TO DEVELOP IN THE SOUTHERN CASCADES OR FAR NRN SIERNEV LATE TODAY AS ITS HARD TO IGNORE THE CONVECTIVE POTENTIAL CONSISTENTLY SHOWN BY MODEL RUNS. BEST INSTABILITY SHIFTS TO OUR SRN SIERNEV ON THURSDAY WHILE MID LEVEL SOUTHWEST FLOW INCREASES SLIGHTLY OVER THE NRN MTNS WITH WEAK SOUTHWEST OVER THE SIERNEV KEEPING BUILDUPS NEAR THE CREST. WILL LOOK MORE AT THIS FOR AFTERNOON PACKAGE. SHOULD SNEAK OUT ANOTHER WARM DAY ON THURSDAY THOUGH MARINE INFLUENCE SHOULD BE FELT IN THE DELTA AND MAYBE SAC AREA AS DEPTH INCREASES. H85 TEMPS LOWER 1-2C OVER THE REGION. SFO-SAC GRADIENT INCREASES TO 2.5-MB BY 00Z FRIDAY LEADING TO A DELTA BREEZE THURSDAY NIGHT. GRADIENT INCREASES TO 3.5-MB FRIDAY. GOOD DELTA BREEZE SHOULD CONT INTO FRIDAY NIGHT WITH A STRONGER SHORT WAVE REACHING THE OREGON BORDER AND DROPPING A WEAK COLD FRONT INTO NORCAL ON FRIDAY. PRECIP WITH THIS FRONT LOOKS MARGINAL FOR OUR CWA. INCREASING H85-5 SOUTHWEST FLOW FRIDAY. .STO...NONE. TARDY ca AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 855 PM EDT WED APR 25 2001 00 UTC SURFACE ANALYSIS SHOWS A WAVY, NORTH-SOUTH ORIENTED MOISTURE BOUNDARY FROM THE NORTHEAST GULF UP TO THE APPALACHIANS. THE KTLH SOUNDING WAS MUCH DRIER AND MORE STABLE THAN 12 HOURS AGO. THE LATEST RUC FORECASTS DRY AIR ADVECTION TO CONTINUE AT THE SURFACE, AND FOR THE REMAINING CLOUDS OVER EASTERN SECTIONS TO SLOWLY DISSIPATE. WILL NOT MAKE ANY MAJOR ADJUSTMENTS TO THE ZONES...EXCEPT TO TAKE OUT SLIGHT POPS FROM SOUTHEASTERN ZONES. THE CWF LOOKS FINE. .TLH... AL...NONE. GA...NONE. FL...RED FLAG WARNING ALL BUT IMMEDIATE COAST THURSDAY AFTN. FOURNIER fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON KY 1045 AM EDT WED APR 25 2001 THE CURRENT RUC MODEL SHOWS THAT THE CLOUDS WITH THE SHORT WAVE APPROACHING FROM IL WILL EVAPORATE BY THIS EVENING. THE CURRENT ZONE FORECASTS LOOK FINE AND WILL NOT BE CHANGED. .JKL...FREEZE ADVISORY TONIGHT FOR ZONES 052-058>060-068-069-085>088- 104-106>120 FROST ADVISORY TONIGHT FOR ZONES 044-050-051-079-080-083-084 FIRE WEATHER WATCH FOR EASTERN KENTUCKY THIS AFTERNOON SCHAUB ky SOUTHEAST MICHIGAN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1020 AM EDT WED APR 25 2001 WILL UPDATE THE ZONES IN A FEW TO CLEAN UP MORNING WORDING. SHORTWAVE OVER NORTHERN ILLINOIS SHOWING UP NICELY ON WATER VAPOR...VISIBLE AND CHICAGO RADAR. THIS WILL SLIDE TO THE SOUTH OF THE AREA WITH A FEW HOURS OF MOSTLY MIDLEVEL SCT-BKN SKIMMING MONROE AND LENAWEE COUNTIES. SATELLITE AND RUC ALSO SHOW A POCKET OF 700MB MOISTURE OVER CENTRAL LAKE MICHIGAN...THIS WILL SLIDE EASTWARD THIS AFTERNOON OVER THE SAGINAW VALLEY AND THUMB...HOWEVER...OMEGA LIFT TO GO NEGATIVE WHICH SHOULD DISSIPATE MOST OF THE CURRENT CLOUDS ASSOCIATED WITH IT. OVERALL...SHOULD BE A MOSTLY SUNNY DAY...WITH JUST A FEW CLOUDS. TEMPS RISING QUICKLY THIS MORNING FROM ITS COOL START IN THE LOW 30S. 850 TEMPS ABOUT 0 TO -2 FOR MOST OF THE AFTERNOON...AS MIXING BEGINS...TEMPS SHOULD SLOW DOWN THEIR UPWARD TREND. RIGHT NOW...CURRENT FORECAST HIGHS AROUND 60 LOOKS ON TRACK. DRC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 721 PM EDT WED APR 25 2001 SHRA ARE POPPING UP OVER THE WRN UPSTATE AND SRN NC MTNS ATTM. MSAS SHOWS SEVERAL HOURS OF MOISTURE CONVERGENCE IN THE WRN UPSTATE. DWPTS AS HIGH AS THE L50S ARE BEGINNING TO ADVECT IN FROM THE SE. ETA SOUNDINGS INDICATED THAT LAPSE RATES WL ONLY STEEPING OVER THE NEXT FEW HOURS AS STRONG VORT CROSS THE CWA. THUS...EXPECT SHRA TO ORGANIZE A LITEL AS THEY CONTINUE TO TO MOVE SE INTO BETTER MOISTURE. WL UPSTATE ZONES FOR 40 POP SHRA FROM PICKENS TO GREENWOOD AND POINTS SW. ETA AND 21Z RUC GENERATE A NICE AREA OF 60-70% RH/S OVER THE WRN UPSTATE STARTING NOW...BUT MUCH DRIER IN MTNS. THUS...THINK CONVECTION WL MOVE OFF THE HIGHER TERRAIN AND NOT BE A FACTOR THERE MUCH LONGER. AT LEAST NOT IN NC...WL ALSO INCLUDE POPS FOR SC MTNS. FCSTID = 14 GSP 42 70 43 78 / 20 0 0 0 AND 43 71 44 79 / 20 0 0 0 CLT 41 69 43 78 / 20 0 0 0 HKY 40 67 42 78 / 20 0 0 0 AVL 37 66 37 75 / 20 0 0 0 .GSP... GA...NONE. NC...FROST ADVISORY FOR LATE TONIGHT FOR ZONES NCZ033...NCZ049>050. SC...NONE. MCAVOY sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 944 PM EDT WED APR 25 2001 WILL OPT TO UPDATE ZFP TO MAKE A FEW MINOR CHANGES TO THE FIRST PERIOD. HI PRESS RIDGE TO CONT TO BE LOCATED ACRS THE FA TONITE. THIS RIDGE TO START TO SLIDE TO THE EAST OF THE FA ON THU...AS A CF DROPS DOWN ACRS THE GREAT LKS REGION AND SRN CANADA. UPR TROF TO MOVE ACRS THE FA TONITE. S/W (AS SEEN IN H2O VAP IMAGERY) TO MOVE ACRS QUE TONITE. 21Z RUC SHOWS TEMPS TO GET DOWN INTO THE M30S-L40S TONITE. T1MIN TEMPS ARE IN THE 20S. CURRENT OBS TRENDS INDICATE THAT RUC TEMPS ARE PROLLY TOO WARM AND MIGHT BE AN UPR LIMIT TO TONITE/S LOW TEMPS. FEW TWEAKS TO FIRST PERIOD TEMPS (MOSTLY TO WIDEN RANGES) BASED ON THIS. SFC WINDS TO MOSTLY BE LT OVRNITE TONITE...AS CURRENT FORECAST INDICATES. MID-LVLS TO BE DRY TONITE AND ON THU. NOT MUCH IN THE WAY OF LOW-LVL MOISTURE TO BE LOCATED ACRS THE FA AS WELL TONITE. H85 NEUTRAL ADVECTION TO TAKE PLACE ACRS THE FA TONITE...THEN WK WAA DEVELOPING ACRS THE FA ON THU. LOW-LVLS TO BE DRY THU. PW VALUES APPEAR TO BE AROUND 0.25" ACRS THE FA TONITE AND ON THU. NO PCPN EXPECTED THOUGH EITHER TONITE OR ON THU. GOES-8 IR SAT PIX SHOW CU FIELD DYING ACRS PART OF THE FA ATTM WHILE HIR LVL MOISTURE CONTINUES TO MOVE TO THE EAST OF THE FA. FEW MINOR COSMETIC CHANGES GOING ZFP OTRW EVERYTHING ELSE LOOKS PRETTY GOOD. HYDRO-WISE...FLW STILL IN EFFECT FOR CENV1 AND WILL MOST LIKELY BE DROPPED SOMETIME ON THU. LK CHAMP WILL CONT TO BE ABOVE FS FOR QUITE SOME TIME THOUGH. BTV ASOS OTS ATTM AND ET ON THE WAY TO FIX IT. MANUAL OBS UNDERWAY HERE ATTM. WORK ZONES OUT UNDER ALBWRKCWF. FINAL ZFP BY 10 PM. .BTV...FLW FOR CENV1 AND FOR LK CHAMP. MURRAY vt EAST CENTRAL FLORIDA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 243 AM EDT THU APR 26 2001 CURRENTLY...SLOW MOVING COLD FRONT MARKED PRETTY WELL NEAR CANAVERAL BY BAND OF DIMINISHING SHOWERS. NORTH WINDS ALSO STARTING TO KICK IN ACROSS NORTHERN SECTIONS. EXTENSIVE LOW CLOUDINESS EXTENDS WELL TO THE NORTH IN AREA OF LOW LEVEL CYCLONIC FLOW ASSOCIATED WITH LOW OFF THE CAROLINA COAST. TODAY...FRONT SHOULD START TO ACCELERATE TO THE SOUTH AS LOW DEEPENS. HOWEVER...MODELS INDICATE H85 TROUGH LAGGING WITH AXIS PASSING THROUGH THE THE NORTH BY MIDDAY AND REACHING THE SOUTH DURING THE AFTERNOON. SURFACE-850 RH STAYS ABOVE 70 PERCENT UNTIL PASSAGE OF THIS TROUGH. THEREFORE WILL HAVE TO CARRY CONSIDERABLE CLOUDS THROUGH AT LEAST THE FIRST HALF OF THE DAY. NORTH NORTHEAST FLOW OFF OF ATLANTIC SHOULD RESULT IN THE SLOWEST CLEARING ALONG COASTAL SECTIONS. GUIDANCE INDICATING CLEAR SKIES TONIGHT WITH DIMINISHING NORTHEAST WINDS. WILL CONTINUE TO MENTION SOME COASTAL CLOUDINESS THOUGH. SURFACE HIGH BUILDING ACROSS GEORGIA MAY ALLOW ONSHORE WINDS TO DIMINISH LATE ACROSS THE NORTH AND EXPECT A NOTABLE INLAND/COASTAL RANGE OF TEMPS. FRIDAY...RIDGE ALIGNS ITSELF ALONG 30N WITH SURFACE WINDS VEERING TO EAST NORTHEAST. FORECAST SOUNDINGS SHOW AN EXTENSIVE LAYER OF DRY AIR. CIRRUS DECK ALSO NOTED (OUT AHEAD OF MID/UPPER TROUGH MOVING INTO THE WESTERN GULF). SHOULD ALSO BE SCATTERED MARINE CLOUDINESS IN NORTHEAST FLOW THAT DEEPENS TO H85. ALL IN ALL IT LOOKS LIKE A PARTLY SUNNY DAY. EXTENDED...NORTHWARD ADVANCE OF DEEP MOISTURE CONTINUES TO LOOK SLOW AS EXTENSIVE MID LEVEL DRY LAYER WILL ONLY BE GRADUALLY MODIFIED. SURFACE RIDGE ALONG 30N WILL WEAKEN SATURDAY AS IMPRESSIVE BACKDOOR FRONT MOVES DOWN THE EASTERN SEABOARD. FRONT DOES NOT LOOK LIKE IT WILL REACH THE AREA BUT STRONG HIGH BUILDING TO THE MID ATLANTIC COAST WILL KEEP PERSISTENT EASTERLY FLOW. PERSISTENT WEAK CYCLONIC FLOW ACROSS THE GULF TRAPPED BENEATH RIDGE ACROSS THE MID SECTION OF THE COUNTRY WILL PROVIDE CONSIDERABLE MID/HIGH CLOUDINESS. EVENTUALLY THE ATMOSPHERE WILL MOISTEN ENOUGH FOR A CHANCE OF RAIN...BUT PROBABLY WILL WAIT UNTIL MONDAY...EXCEPT FOR SLIGHT CHANCE SOUTHERN COASTAL POPS OVER THE WEEKEND. FIRE WEATHER...PLAN ON HOLDING OFF ON WATCH FOR FAR NRN AREAS TODAY AS MODELS PROG DRIEST LOW LVL AIR TO REACH NRN CWA THIS EVENING AND TONIGHT. STILL COULD SEE MIN RHS DROP TO ARND 40 PCT WITH GUSTY WINDS ACROSS FAR NRN SECTIONS SO DAY SHIFT WILL HAVE TO MONITOR CLOSELY. FOR FRI...FIRE WX WATCH WILL BE POSTED FOR NRN INTERIOR SECTIONS FOR MARGINAL DURATIONS OF LOW RH. COORD WITH TBW. MARINE...20 KNOT OR GREATER NORTH WINDS JUST NORTH OF THE WATERS. RUC AND MESO ETA SHIFT THIS SURGE INTO NORTHERN SECTIONS THIS MORNING AND THE SOUTHERN LEG BY AFTERNOON. ADVISORY CONDITIONS WILL CONTINUE TONIGHT...MAINLY FOR SEAS IN THE NORTH THOUGH...AS GRADIENT SHOULD WEAKEN SLIGHTLY THERE. WEAKENING SURFACE RIDGE ALONG 30N WILL KEEP WINDS 15 KNOTS OR LESS FRIDAY AND SATURDAY. AVN SHOWS GRADIENT TIGHTENING TO ADVISORY LEVELS BY SUNDAY AS HIGH REBUILDS TO THE NORTH. PRELIMINARY CCF NUMBERS... DAB BB 073/056 076/056 078 -000 MCO BB 078/057 079/059 082 -000 MLB BB 076/061 078/066 079 -000 .MLB...SCA FLAGLER BEACH TO JUPITER INLET. ...FIRE WEATHER WATCH FRI AFTN FOR LAKE...SEMINOLE...ORANGE INLAND VOLUSIA. PUBLIC/MARINE...LASCODY AVIATION/FIRE WX...VOLKMER fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 232 AM EDT THU APR 26 2001 SYNOPSIS: MOISTURE DISCONTINUITY CLEARLY EVIDENT IN SURFACE ANALYSIS EARLY THIS MORNING RUNNING FROM SW TO NE ACROSS GA. DEW POINTS ARE IN THE 30S IN ATL AND CSG AND POINTS N AND W...BUT IN THE 50S IN MCN AND ABY AND POINTS S AND E. THIS MAY THROW A FLY IN THE OINTMENT FOR THIS MORNINGS FORECAST. ABY ALREADY SHOWING 6SM VSBY. SATELLITE PIX ALSO SHOWING CEILINGS ABOUT 1000-1500 FT ADVECTING SWWD ACROSS SE GA AND NE FL. THESE CLOUDS WILL MAKE IT INTO OUR ERN ZONES. POST FRONTAL CLOUDS BEHIND YESTERDAY/S FRONT...WHICH APPEARS TO HAVE STALLED ACROSS THE CENTRAL PENINSULA...HAVE RECENTLY CLEARED DIXIE CO. AT UPPER LEVELS...SHORT WAVE ENERGY IS ROUNDING THE BASE OF THE TROUGH IN SC. MODEL DISCUSSION: GRADUALLY PROGRESSIVE PATTERN TO CONTINUE ACROSS THE CONUS THROUGH THE SHORT RANGE. ERN U.S. TROUGH SWINGS TO NC COAST TODAY AND SPINS UP A SURFACE LOW E OF HATTERAS. BOTH FEATURES THEN MOVE NE AWAY FROM THE COAST AS SURFACE HIGH PRESSURE SETTLES OVER THE SE CONUS. THE WRN U.S UPPER RIDGE AXIS BUILDS EWD TO THE CENTRAL N AMERICA BY SAT. PUBLIC FORECAST: ETA AND NGM TIME HEIGHT CROSS SECTIONS DEPICT ENOUGH SURFACE RH FOR A LIGHT FOG IF WINDS DECOUPLE. WILL KEEP AN EYE ON THE OBS AND THROW PATCHY FOG IN THE ERN ZONES IF NECESSARY. MOST LIKELY...IT WILL NOT BE SIGNIFICANT ENOUGH TO MENTION. MOST MODELS NOT HANDLING STRATUS DECK VERY WELL...ALTHOUGH THE LATEST RUC SHOWS IT MIXING AWAY QUICKLY AFTER SUNRISE. MAY NEED TO MENTION SOME MORNING CLOUDS IN OUR SE ZONES. AFTER THAT...IT/S CLEAR SAILING FOR A COUPLE OF DAYS AS WE HAVE BASICALLY A TEMP AND WIND FORECAST INTO THE WEEKEND. TEMP GUIDANCE GENERALLY LOOKS GOOD...EXCEPT MAV MIN TEMPS ARE TOO COOL FOR TLH THE NEXT TWO NIGHT. FAN LOOKS BEST. MARINE: IT APPEARS NOCTURNAL MIXING OVER THE WATERS IS NOT AS EFFICIENT IN THE MOIST AIR AND 42036 HAS YET TO REACH SCEC...EXCEPT BRIEFLY BEHIND A GUST FRONT FROM EARLIER CONVECTION AROUND GNV WHICH IS BEING PROPELLED SWWD IN THE NE FLOW. MODELS SHOW THAT WINDS WILL NOT STAY UP HERE...SO WILL LIKELY REMOVE HEADLINE FOR E LEG. WINDS THEN GO THROUGH THEIR DIURNAL FLUCTUATIONS...BUT REMAIN BELOW CRITERIA THROUGH SAT. LONG DURATION E FLOW SETS UP FROM SAT ONWARD WITH THE GRADIENT TIGHTENING ENOUGH TO SEE HEADLINES AGAIN BY SUN. FIRE WX: RED FLAG WARNING ALREADY IN PLACE FOR TODAY LOOKS GOOD...ALTHOUGH WE MAY NOT MEET CRITERIA ALONG THE IMMEDIATE COAST. A WATCH WILL BE POSTED FOR LOW RH DURATIONS ON FRI. EXTENDED: AVN STILL SHOWS A WEAK WAVE MOVING NWWD INTO THE CENTRAL GULF BY EARLY NEXT WEEK WITH AN UPPER LOW OVER TX MOVING E TOWARD THE GULF. LOW LEVEL ELY FLOW IMPLIES BETTER RAIN CHANCES FOR S AND CENTRAL FL. THE NRN EXTENT OF THIS MOISTURE NEXT WEEK IS STILL IN QUESTION...BUT CHANCE POPS IN CURRENT FORECAST LOOK REASONABLE FOR MID WEEK. NO CHANGES PLANNED. PRELIM NUMBERS... TLH 79 45 82 48 0000 PFN 78 55 77 58 0000 DHN 78 52 83 55 0000 ABY 77 47 82 51 0000 VLD 77 46 82 50 0000 .TLH... AL...NONE. GA...NONE. FL...RED FLAG WARNING ALL BUT IMMEDIATE COAST 11 AM TO SUNSET TODAY. FIRE WEATHER WATCH ALL BUT IMMEDIATE COAST 11 AM TO SUNSET FRI. WOOL fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 208 AM CDT THU APR 26 2001 SHORT TERM... IF THERE WAS A DAY TO KEEP A 20 POP IN THE FORECAST, TODAY'S THE DAY. PROGGED WARM ADVECTION UNDERWAY, CONFIRMED BY VEERING PROFILER WINDS, AND INCREASING LOW LEVEL JET IN NORTHERN IA INTO MN. CURRENT RUC 850-700MB QN SHOWING WHERE LIFT IS OCCURRING NICELY WITH IR CLOUD FIELDS IN MN/WI AND ALSO IN CENTRAL KS. DRY SOUNDINGS MAKING IT TOUGH FOR ANY PRECIP TO DEVELOP. LAST FEW IR IMAGES SHOWING AC DEVELOPMENT IN NW IA, WHICH MAY EXPAND SOME WHILE LLJ PEAKS NEXT COUPLE HOURS. NOT EXPECTING PRECIP AT THIS POINT GIVEN LACK OF MOISTURE/INSTABILITY. THERMAL RIDGE AT SURFACE-850MB WILL ALIGN ITSELF ACROSS NORTHERN IA AHEAD OF COLD FRONT THIS AFTERNOON WITH 80-85 TEMPS A SOLID BET. WEAK TO MODERATE CONVERGENCE PROGGED BY META/AVN/NGM MODELS, WITH GOOD AGREEMENT ON TIMING. EVAPORATION DID INDEED RAISE SURFACE DEW POINTS IN WET AREAS IMMEDIATELY NW OF IA, AND SOME OF THIS MOISTURE MAY POOL AGAIN TODAY ALONG FRONT, BUT LIKELY MUCH SHORT OF THE LOW 60 DEW POINTS FORECAST BY THE META. THIS SHOULD CUT CAPES TO AROUND 1000 J/KG. AGREE WITH SPC DY1 OUTLOOK. AMPLE HEATING SHOULD AID SURFACE BASED INSTABILITY DURING SHORT WINDOW 21Z-02Z. FRONT WILL SLIDE S OF IA BY 06Z, SO WILL INCLUDE AN EVENING 20 POP ALO-AMW-DNS AND S. LONGER TERM... SOME WEAK COLD ADVECTION TONIGHT INTO FRIDAY WILL TRIM LOWS BY A FEW DEGREES TONIGHT, AND HIGHS ON FRIDAY, BUT NOT MUCH. BOUNDARY STALLS IN NORTHERN MO AND KS BEFORE RETURNING N FRIDAY NIGHT. POOLING OF MOISTURE FRIDAY NIGHT DESTABILIZES ELEVATED MIXED LAYER WITH SHOWALTERS DROPPING SLIGHTLY BELOW 0, ALONG WITH A GENERAL INCREASE IN THE LLJ ALONG ENTIRE STRETCH OF BOUNDARY. RESULTING THETAE ADVECTION MAY DRIVE A NARROW BAND OF ELEVATED CONVECTION BETWEEN 06-12Z IN OUR CWA, OF WHICH THE ETA/AVN AGREE ON SOME LIMITED QPF. WILL GO WITH A 30 POP FRIDAY NIGHT. EXTENDED... WILL DOUBLE CHECK NEW MRF, BUT DO NOT ANTICIPATE CHANGES TO EXTENDED EXCEPT FOR PERHAPS SATURDAY MORNING PRECIP FROM OVERNIGHT CONVECTION. .DSM...NONE KULA ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 350 AM EDT THU APR 26 2001 MAIN CONCERN IS LGT PCPN CHCS TDA IN ASSOCIATION WITH WK CDNFT. WV IMAGERY AND RUC IDENTIFY A SHRTWV OVER NEW ENGLAND STATES THIS AM AND A CUTOFF LOW OVER SC. A WEAK UPPER LEVEL LOW WAS ALSO OVER WESTERN HUDSON BAY. TO THE WEST A RIDGE CONTINUES TO BUILD OVER WRN ROCKIES AND CAN BC. A CDFNT STRETCHES ACRS MN THIS AM FROM THE LOW OVER WESTERN HUDSON BAY. A SFC RIDGE DOMINATES THE LOW LEVELS OVER THE NE CONUS. THE ROCKIES IS DOMINATED BY THIS RIDGE. MDLS IN GOOD AGREEMENTS IN THE TRACKING OF SYS THROUGH FA DURING THIS FCST PERIOD. THE SC LOW WILL MOV OFF INTO THE WRN ATLANTIC TODAY. THE HUDSON BAY LOW WILL SHIFT TO NRN QUEBEC DRAGGING THE CDFNT THRU UPR MI. A RIDGE WILL SLIDE INTO MANITOBA AND NRN PLAINS. THERE IS CONSIDERABLE 300K ISENTROPIC LIFT ACRS THE FORECAST AREA AHEAD OF THE COLD FRONT. CONDITION MARGINALLY DRY WITH A BAND OF MEAN SFC-H85 RH OF >80 PCT. A LOW LEVEL JET WILL BE JUST AHEAD OF THE CDFNT. THE AIR MASS FOLLOWING THE FRONT WILL DRY OUT WITH THE MEAN RH FALLING TO <30PCT. AS THE FRONT PASSES EXPECT ENOUGH LIFT TO DEVELOP A FEW SHOWERS...ESPECIALLY OVER THE EASTERN PART OF FA TODAY. WITH THE DRYNESS OF THE ATMOSPHERE...THE LATEST ETA SHOWING CAPE VALUES TO REMAIN LESS THAN 200J/KG AND LI'S >4 IN ASSOC WITH FROPA. HOWEVER...BY THIS AFTERNOON...THE 85KT ULJ MAX WILL MOVE E...PLACING THE THE ERN UP PLACING THE UNDER ITS LEFT EXIT REGION. A WEAK SHRTWV WILL PASS OVR THE EASTERN U P AS WELL. IN SPITE OF LIMITED CAPE VALUES AND LIMITED MOISTURE...THE ULJ/SHRTWV ENERGY AND THE CDFNT WILL SUPPORT A POSSIBLE TSRA OR TWO OVER ERN PART OF FA TDA. THE SFC RIDGE WILL SLIDE INTO MN TONIGHT FOLLOWING THE CDFNT. AS THE RIDGE BUILDS OVER THE AREA TONIGHT WINDS WILL DIMINISH. THE MEAN SFC-H50 RH WILL REMAIN <50 PCT TONIGHT. UNDER THE INFLUENCE OF THE RIDGE...ISENTROPIC ANLYS SHOWING CONSIDERABLE SUBSIDENCE TAKING PLACE. WINDS WILL BE LIGHT...THUS EXPECT A FAIR AMOUNT OF RADIATIONAL COOLING. THE RIDGE WILL REMAIN OVER THE UPPER GREAT LAKES THROUGH FRIDAY NIGHT ALONG WILL CONT DRY COND. .MQT...NONE. DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 330 AM CDT THU APR 26 2001 FORECAST FOCUS ON POSSIBLE CONVECTION WITH FRONT LATER TODAY AND THIS EVENING. IN THE SHORT TERM...ETA/AVN/NGM/RUC PROGOLOGY IN VERY CLOSE AGREEMENT WITH SPEED OF COOL FRONT FROM NORTHWEST MINNESOTA THROUGH CWA THIS AFTERNOON/EARLY EVENING. PROGS GENERALLY AGREE THAT CORE OF UPPER JET REMAINS WELL AWAY FROM CWA ALONG WITH DECENT 500 MILLIBAR VORTICITY. HOWEVER CURRENT SATELLITE/RUC 500 MILLIBAR PROG COMBO SHOWS 11 UNIT VORTICITY ENTERING NORTHWEST MINNESOTA PRECEDED BY AREA OF CLOUDS IN VICINITY OF FRONTAL BOUNDARY. 700 MILLIBAR PROGS MORE INSISTENT WITH SLUG OF MOISTURE AND GOOD VERTICAL MOTION TIMED WITH FRONT/S ARRIVAL DURING MAXIMUM DAYTIME HEATING. IN ADDITION 850 MILLIBAR THERMAL RIDGE COINCIDES WELL WITH FRONTAL BOUNDARY AS WELL. ONLY MINOR DRAWBACK IS THAT LOW LEVEL CONVERGENCE NUMBERS...WHILE FOCUSED ALONG FRONT...ARE NOT VERY HIGH. NEVERTHELESS FEEL CURRENT FORECAST FOR TIMING AND CHANCY NATURE OF SHOWERS/THUNDERSTORMS ON THE MARK...SO WILL NOT CHANGE WORDING AT THIS POINT. IN THE FAR TERM...HIGH PRESSURE PASSES TO THE NORTH OF CWA AFTER FRONTAL PASSAGE TONIGHT. WEATHER NIL WITH NORTHEAST WINDS MAIN CHALLENGE TO TEMPERATURE FORECAST. .MKX...NONE. $$ ZAJDEL wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 935 AM EDT THU APR 26 2001 CLOUDS PERSISTING IN FOOTHILLS/PIEDMONT...EXCEPT N OF I-40. WILL CHANGE SKY COVER TO PARTLY CLOUDY...AND RESIST URGE TO RAISE MAXIMUMS...DESPITE LOW LEVEL THICKNESS SUPPORTING WARMER TEMPERATURES. RUC SHOWS N FLOW AND COLD ADVECTION CONTINUING THROUGH DAY...AND DELAYED WIND SHIFT UNTIL THIS EVENING. DID RAISE MAXIMUM I-40 CORRIDOR WHERE CLOUDS ABSENT. TEMPERATURES IN UPPER 20S TO MID 30S COMING IN FROM PORTIONS OF NC MOUNTAINS THIS MORNING...DESPIT HIGIH DEW POINTS AT MTR STATIONS. TONIGHT WILL BE EVEN BETTER RADIATIONAL NIGHT WITH LESS WIND AND LESS CLOUDS...SO HAVE EXTENED FROST ADVISORY INTO N NC MOUNTAINS ...AND CONTINUED IT IN S AND C NC MOUNTAINS. ALSO ISSUED SPS FOR SCATTERED FROST GA/SC MOUNTAINS. FCSTID = 7 GSP 71 42 79 48 / 0 0 0 0 AND 71 43 80 50 / 10 0 0 0 CLT 70 41 78 47 / 0 0 0 0 HKY 69 40 76 48 / 0 0 0 10 AVL 69 36 74 43 / 0 0 0 0 .GSP... GA...NONE. NC...FROST ADVISORY FOR THURSDAY NIGHT FOR ZONES NCZ048... NCZ051>053...NCZ058>059...NCZ062>065. FROST ADVISORY FOR THURSDAY NIGHT FOR ZONES NCZ033...NCZ049>050. SC...NONE. sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NASHVILLE TN 925 AM CDT THU APR 26 2001 CURRENT ASOS/AWOS OBSERVATIONS AND REGIONAL SATELLITE IMAGERY SHOWING CLEAR SKIES ACROSS THE MID STATE...AND MUCH OF THE E U.S. TEMPS ARE IN THE MID TO UPPER 50S...DEWPOINT DEPRESSIONS 15 TO 20 DEGREES...UNDER LIGHT AND VARIABLE WINDS. MSAS SFC ANALYSES DEPICTING RIDGING APEX ACROSS THE AREA. UPPER AIR HAND CHARTS ILLUSTRATING DEVELOPING NWLY FLOW WITH HEIGHT...ALTHOUGH RATHER WEAK...AND DRY CONDITIONS REGIONALLY AND UPSTREAM. BROAD RIDGING OVER THE W U.S. RESULTING IN THIS. 12Z UPPER AIR RUN SHOWING DRY CONDITIONS ALSO ACROSS THE AREA. RUC MODEL SHOWING CONTINUANCE IN CWA/S WEATHER PATTERN THROUGH THE AFTERNOON HOURS. FORECAST MAX SOUNDING TEMPERATURES "RIGHT IN LINE" WITH FORECASTED HIGH AT BNA. LAMP GUIDANCE VALUES ALSO "RIGHT IN LINE" WITH REGIONAL FORECASTED HIGHS. AS A RESULT...SEE NO NEED TO UPDATE FORECAST AT THIS TIME. $$ 14 JBW tn SOUTHWEST ARIZONA/SOUTHEAST CALIFORNIA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PHOENIX AZ 940 AM MST THU APR 26 2001 .SYNOPSIS... HIGH PRESSURE OVER THE WESTERN STATES WILL LEAD TO ABOVE NORMAL TEMPERATURES TODAY AND FRIDAY. SOME INCREASE IN MOISTURE OVER SOUTHEAST ARIZONA WILL PROVIDE A SLIGHT CHANCE FOR AFTERNOON THUNDERSTORMS OVER THE HIGHER TERRAIN OF SOUTH CENTRAL ARIZONA. A WEAK LOW PRESSURE SYSTEM IS FORECAST TO MOVE INTO THE WESTERN STATES THIS WEEKEND...PROVIDING SLIGHTLY COOLER TEMPERATURES SUNDAY AND MONDAY. .DISCUSSION... WEAK UPR LVL TROF WELL S AND E OF US THIS MORNING WITH ERN PACIFIC TROUGH JUST OFFHSORE AT 12Z. 500MB FLOW WAS STILL VERY SLUGGISH ACROSS ALL OF AZ WITH STRONGER SW FLOW OVER CA. IN FACT HGT FALLS WERE IN THE 30 TO 60M RANGE OUT WEST AND BEGINNING TO FALL ACROSS SERN AZ. I PUT THE CENTER OF THE UPR HIGH JUST SW OF ABQ...VERY CLOSE TO THE 12HR EXPECTED POSITIONS. MSTR AND TEMP PROFILES WERE ALSO ABOUT AS EXPECTED WITH SUF MSTR AND GOOD LAPSE RATES FOR AT LEAST AN ISOLATED TSTM OR TWO OVR HIGHER TERRAIN OF ZONE 24/28SFC DEW POINTS ALSO HAVE INCHED UPWARD...TO 45 TO 50F...RESULTING FROM LAST NIGHTS OUTFLOWS. LATEST GOES P-WTR DATA NOW HAS A .75 INCH MAX ABOUT OVER TUCSON. CURRENT FORECASTS WHICH MENTION A SLIGHT CHANCE FOR AFTERNOON MOUNTAIN CONVECTION OVER THE EASTERN PORTIONS OF THE CWA (ZONES 28 AND 24) TODAY AND FRIDAY STILL LOOK OK. RUC PUMPS UP THE NM HIGH JUST A BIT TODAY WHILE IT ALSO SHOWS THE BULK OF CONVECTION FAR TO SOUTHEAST WITH A MAX ALONG THE MTNS OF NRN MEXICO. ALSO NOTED IS TROFFING LITTLE DEEPER OVER CALIFORNIA WITH SOME SHWRS/TSTMS IN NV. TEMP-WISE WE OUGHT TO STAY IN THAT UPR 90S TO NEAR 100 RANGE WITH JUST A HINT OF COOLING ... NOT AS HOT ... FOR FRI. MOS SHOWS A LTL DIFFERENT SCENARIO WITH A 3-DAY PLATEAU IN MAX TEMPS. SIPPLE az AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 400 PM EDT THU APR 26 2001 THE CURRENT WATER VAPOR LOOP SHOWS A WELL DEFINED MID LEVEL CIRCULATION OVER NORTHERN ONTARIO. AT THE SURFACE...THE LATEST ANALYSIS SHOWS LOW PRESSURE OVER JAMES BAY WITH AN ASSOCIATED COLD FRONT EXTENDING ACROSS EASTERN LAKE SUPERIOR AND INTO THE CENTRAL UP AND EASTERN WISCONSIN. AHEAD OF THIS FRONTAL BOUNDARY...LOW LEVEL WARM AIR ADVECTION AND SURFACE CONVERGENCE HAS LED TO SCATTERED -SHRA ACROSS MUCH OF THE FORECAST AREA THIS AFTERNOON. THE MAIN FORECAST CONCERNS THIS PACKAGE REVOLVE AROUND THE TIMING OF THIS PRECIP EXITING THE FORECAST AREA...ALONG WITH A SUBSTANTIAL WARMING TREND IN THE EXTENDED. THE 12Z MODELS ARE IN GOOD GENERAL AGREEMENT THROUGH 60 HOURS BY SHOWING AN AMPLIFYING LONG WAVE RIDGE ACROSS THE CENTRAL US...WITH SURFACE HIGH PRESSURE MOVING ACROSS THE GREAT LAKES. TONIGHT...THE LATEST MESO-ETA AND RUC ARE SHOW THE COLD FRONT PASSING ACROSS FAR NORTHERN LOWER BETWEEN 21 AND 00Z AND THEN EXITING THE SOUTHEASTERN COUNTIES AROUND 03Z. PRE-FRONTAL SHOWER ACTIVITY WILL CONTINUE INTO THE EVENING AS THE FRONT PASSES. PER COORDINATION WITH DTX...I HAVE DECIDED TO ADD A MENTION OF ISOLATED THUNDERSTORMS ACROSS THE SOUTHEASTERN COUNTIES THIS EVENING. ALTHOUGH THERE IS VIRTUALLY NO SURFACE BASED INSTABILITY (SFC-700MB LAYER NEARLY ISOTHERMAL WITH SURFACE DEWPOINTS STILL IN THE 30S)...700-500MB LAPSE RATES DO APPROACH 7C/KM AROUND FROPA. SKIES WILL QUICKLY BEGIN TO CLEAR FOLLOWING FROPA (AS INDICATED ON THE SATELLITE LOOPS) AS 1000-500MB RH QUICKLY DROPS TO 30 PCT. THERE IS SOME CIRRUS BEHIND THE FRONTAL BOUNDARY...HOWEVER SATELLITE TRENDS SUGGEST THAT THESE WILL QUICKLY MOVE SOUTHEAST BEHIND THE FRONT. THEREFORE I HAVE WORDED THE ZONES AS BECOMING CLEAR FOLLOWING FROPA. WITH SOME SHALLOW COLD AIR ADVECTION BEHIND THE FRONTAL BOUNDARY...TEMPS WILL FALL INTO THE 30S OVERNIGHT (IN LINE WITH CURRENT GUIDANCE). FRIDAY AND FRIDAY NIGHT...AS THE UPPER LEVEL RIDGE AMPLIFYS ACROSS THE CENTRAL US...SURFACE HIGH PRESSURE WILL SETTLE ACROSS THE FORECAST AREA FROM CANADA. 1000-500MB MEAN RH IS PROGGED TO REMAIN AROUND 30 PCT. DAYTIME MIXING WILL BRING DRY AIR TO THE SURFACE...THUS I DO NOT EXPECT ANY CU FORMATION (VIRTUALLY NO CU HAVE DEVELOPED UPSTREAM ACROSS SOUTHERN MANITOBA). IT SHOULD BE AN ALL OUT SUNNY DAY. TEMPERATURES SHOULD ONLY RISE INTO THE 50S ACROSS MOST OF THE FORECAST AREA AS AN 850MB THERMAL TROUGH WILL BE CENTERED OVER THE EASTERN LAKES. WITH MIXING HEIGHTS ON ETA MODEL SOUNDINGS APPROACHING 800MB...MAX TEMPS WILL GENERALLY BE IN THE 50S (WITH A FEW ISOLATED 60S) ACROSS THE FORECAST AREA. DIURNAL MIXING WILL BRING VERY DRY AIR TO THE SURFACE (SHOULD SEE DEWPOINTS FALL TO THE LOWER 20S AND TEENS). THIS WILL BE PROBLEMATIC FOR MIN TEMPS FRIDAY NIGHT WITH THE SURFACE HIGH CENTERED OVER THE FORECAST AREA. LIGHT WINDS AND DRY AIR WILL ALLOW FOR GOOD RADIATIONAL COOLING. I DROPPED TEMPS FROM CURRENT GUIDANCE VALUES (KEEPING THEM IN THE 20S THOUGH). HOWEVER...I CAN NOT RULE OUT A FEW TEENS IN LOW LYING LOCATIONS. SATURDAY AND SATURDAY NIGHT...UPPER LEVEL RIDGE OVER THE CENTRAL US CONTINUES TO AMPLIFY AND PUSH EAST. AT THE SURFACE...THE HIGH PRESSURE WILL PUSH EAST OF THE FORECAST AREA...ALLOWING SOUTHWESTERLY FLOW TO DEVELOP ACROSS THE GREAT LAKES. THIS WILL BE THE START OF A WARMING TREND AS 850MB TEMPS WARM TO +8 ACROSS THE FAR WESTERN COUNTIES BY 00Z. ETA 300K ISENTROPIC ANALYSIS SHOWS SOME GOOD ASCENT WORKING INTO THE WESTERN COUNTIES DURING THE AFTERNOON...WITH CONDENSATION PRESSURE DEFICITS DROPPING TO AROUND 50 MB...LEADING TO SOME MOISTURE CENTERED AROUND 700 MB. I WILL THEREFORE MENTION PARTLY SUNNY SKIES DURING THE AFTERNOON ACROSS THE WESTERN COUNTIES TO ACCOUNT FOR THIS. 850-700MB WARM AIR ADVECTION CONTINUES THROUGH SATURDAY NIGHT...PROVIDING AT LEAST SOME SCATTERED MID LEVEL CLOUDS. THE SURFACE GRADIENT WILL ALSO INCREASE...THUS WE SHOULD NOT DECOUPLE (MIN TEMPS ONLY DROPPING TO AROUND 40). EXTENDED DISCUSSION...THE MODELS CONTINUE TO AGREE ON A SUBSTANTIAL WARMING TREND BEGINNING THIS WEEKEND AND CONTINUING THROUGH NEXT WEEK. THIS WARMING TREND WILL BE THE RESULT OF AN AMPLIFYING PATTERN WITH A LONG WAVE TROUGH DEVELOPING OVER THE WESTERN CONUS AND A RIDGE ACROSS THE EAST. ON SUNDAY...HIGH PRESSURE IS PROGGED OVER THE EASTERN US WITH STRONG SOUTHWESTERLY FLOW/WARM AIR ADVECTION ACROSS THE GREAT LAKES REGION. 850MB TEMPS ARE PROGGED TO WARM TO AROUND +12C ON BOTH THE MRF AND ECMWF...RESULTING IN DAYTIME TEMPS IN THE 70S ACROSS THE FORECAST AREA. ON MONDAY...THE RIDGE BREAKS DOWN A LITTLE AS A WEAK SHORT WAVE AND ASSOCIATED SURFACE COLD FRONT ARE PROGGED TO MOVE INTO THE WESTERN GREAT LAKES REGION. THE FRONT IS PROGGED TO WASH OUT OVER THE FORECAST AREA AS IT ENCOUNTERS THE RIDGE THAT REMAINS OVER THE EASTERN US. SINCE THE EXTENDED MODELS ARE IN GOOD AGREEMENT WITH THIS FRONT UNDERGOING FRONTOLOSIS AS IT ENCOUNTERS THE FORECAST AREA...AND SINCE THEY HAVE BEEN EXHIBITING GOOD RUN TO RUN CONSISTENCY...I FEEL THAT THE CHANCES OF PRECIP ON MONDAY ARE STILL TOO LOW TO MENTION IN THE EXTENDED. BY TUESDAY...THE RIDGE AMPLIFYS AGAIN OVER THE EASTERN US WITH A CONTINUED SOUTHWESTERLY SURFACE FLOW...MAINTAINING THE UNSEASONABLY WARM TEMPERATURES ACROSS THE FORECAST AREA. ON WEDNESDAY...AS THE UPPER LEVEL TROUGH CONTINUES TO DEEPEN ACROSS THE WESTERN US...A COLD FRONT IS PROGGED TO MOVE INTO THE UPPER MISSISSIPPI RIVER VALLEY. THE ECMWF IS SLIGHTLY FASTER WITH THE PASSAGE OF THIS FRONT THAN THE MRF. MRF AND ECMWF ENSEMBLE MEANS HOWEVER DO NOT BRING THE FRONT INTO CENTRAL UPPER/EASTERN WISCONSIN UNTIL THURSDAY MORNING. I WILL THEREFORE BRING A MENTION OF THUNDERSTORMS IN FOR THURSDAY ACROSS THE EASTERN UP (CLOSER TO THE UPPER LEVEL SUPPORT). .APX...NONE. COORDINATED WITH DTX AND MQT. CONSIDINE mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NASHVILLE TN 216 PM CDT THU APR 26 2001 FORECAST QUANDARIES...CLOUD COVER AND ANY POPS FRI NIGHT-SAT MORNING...TEMPS CURRENT ASOS/AWOS OBSERVATIONS AND REGIONAL SATELLITE IMAGERY SHOWING CLR SKIES CONTINUING INTO THE AFTERNOON HOURS ACROSS THE MID STATE...AN MOST OF THE SE U.S. MSAS/HAND SFC DEPICTIONS SHOWING RIDGE APEX CENTERED THROUGH THE REGION. TEMPS ARE IN THE MID TO UPPER 60S...DEWPOINT DEPRESSIONS 20 TO 30 DEGREES...WITH LIGHT AND VARIABLE WIND CONDITIONS. RUC ILLUSTRATING DEVELOPING NWLY FLOW ALOFT...ALTHOUGH RATHER WEAK...AS RIDGING ACROSS THE W U.S. AMPLIFIES. 12Z THU REGIONAL MODEL RUNS THROUGH 12Z SUN IN GOOD AGREEMENT... ESPECIALLY IN THE UPPER LEVELS. ALL MODELS ALSO INITIALIZE WELL... WITH NO MAJOR DIFFERENCES. HOWEVER...ETA BEST INITIALIZED WITH CURRENT SFC HIGH STRENGTH. WILL THUS LEAN TOWARD THE ETA SOLUTION. RIDGING SFC AND ALOFT WILL CONTINUE TO BE THE DOMINATE "WEATHER MAXER" THROUGHOUT THE PERIOD. UPPER LEVEL RIDGE ACROSS THE W U.S. WILL MOVE E AND CONTINUE AMPLIFYING...WITH ITS APEX OVER THE AREA BY 12Z SAT. SFC HIGH PRESSURE WILL CONTINUE ACROSS THE SE U.S...WITH A COOLER HIGH PRESSURE AIRMASS DEVELOPING ACROSS THE GREAT LAKES ON FRI. THIS HIGH PRESSURE DEVELOPMENT WILL CAUSE THE DEVELOPMENT OF A WEAK COLD FRONT BETWEEN THIS HIGH PRESSURE SYSTEM AND THE ONE ACROSS THE SE U.S. AFFECTING THIS REGION. THIS BACK DOOR COLD FRONT IS EXPECTED TO MOVE SWD INTO THE REGION FROM THE OHIO VALLEY AFTER 06Z SAT...AND THEN BE POSITIONED NWD-SEWD ACROSS THE MID STATE BY 12Z SAT. THIS MAY CAUSE SOME INCREASING CLOUDINESS ACROSS N PORTIONS OF THE AREA THROUGH LATE NIGHT FRI INTO THE MORNING HOURS ON SAT...BUT DO NOT BELIEVE PCPN DEVELOPMENT WILL OCCUR. FRONT SHOULD WASH OUT AS SAT PROGRESSES WITH AFTERNOON DECREASING CLOUDINESS. OTHERWISE...SKY CONDITIONS SHOULD REMAIN CLR THROUGH TONIGHT...WITH MOSTLY SUNNY SKIES DEVELOPING ACROSS NORTHERN PORTIONS ON FRI AS FRONT APPROACHES. EXTENDED...SFC AND UPPER RIDGING INFLUENCES WILL MOVE E OF AREA AND BROADEN...WITH APEX INTO THE ATLANTIC STATES BY 12Z TUE. THIS WILL RESULT IN A CONTINUE OF PARTLY CLOUDY SKIES THROUGH THE PERIOD. ANOTHER AMPLIFIED UPPER LEVEL RIDGE WILL THEN MOVE INTO THE REGION ON WED...WITH SFC RIDGING SLIDING TO THE E...ALLOWING FOR A RETURN IN GULF MOISTURE BY THU. WILL LEAVE THU DRY FOR NOW...AND WAIT FOR LATER MODEL RUNS FOR FURTHER CLARIFICATION OF ANY RAINFALL ACTIVITY. TEMPS....WITH GOOD RADIATIONAL COOLING NIGHT IN STORE...WILL UNDERCUT MOS VALUES FOR LOWS A FEW DEGREES. WILL GO WITH A COMPROMISE MOS/ETA BOUNDARY LAYER TEMP SCHEME SOLUTION FOR HIGH/LOW VALUES REST OF PERIOD. PRELIMINARY NUMBERS FOR COORDINATION PURPOSES ONLY... BNA 047/082/052/079 0000 CSV 040/077/047/073 0000 .BNA...NONE. $$ 14 JBW tn