AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1130 AM CDT WED APR 21 2004 .DISCUSSION... UPDATED THE FORECAST FOR MORE CLOUD COVER THIS MORNING ESPECIALLY EASTERN IL AND FROM PEORIA NORTH. THEN HAVE SKIES BECOMING PARTLY TO MOSTLY SUNNY THIS AFTERNOON NORTH OF I-70. CONTINUED PROB30/40 CHANCE OF CONVECTION THIS AFTERNOON FROM I-57 EAST UNTIL COLD FRONT PASSES. COLD FRONT NEAR I-55 AND RUC AND MESOETA EXIT COLD FRONT SE OF LAWRENCEVILLE BY 00Z. INCREASE WINDS TO BREEZY LEVELS OF 15 TO 25 MPH THIS AFTERNOON AS SOUTHWEST WINDS TURN WEST BEHIND THE COLD FRONT. 16Z SURFACE ANALYSIS HAS 997 MB LOW JUST SOUTH OF MANITOWOC WI WITH A COLD FRONT EXTENDING SSW ALONG I-55 OVER CENTRAL IL. DEWPOINTS IN THE MID 50S TO LOWER 60S DROP INTO THE 40S BEHIND THE COLD FRONT AS SW WINDS TURN WNW. BRUNT OF CONVECTION IS AHEAD OF PREFRONTAL TOROF JUST SE OF ILX CWFA AND MOVING EAST AWAY FROM IL. SPC SLIGHT RISK OF SEVERE STORMS WITH LARGE HAIL AND DAMAGING WIND GUSTS THIS AFTERNOON STILL SE OF I-70 WHERE LIFTED INDICES OF MINUS 5 TO 6C AND CAPES UP TO 1500 J/KG UNTIL COLD FRONT PASSES LATE THIS AFTERNOON AND EARLY EVENING. 11 AM TEMPS IN THE MIDDLE TO UPPER 60S...EXPECT 54 TO 59 FROM QUINCY AND PEORIA NORTH. HIGHS TO RANGE FROM 65 FAR NW BY GALESBURG...TO 75 FAR SE BY LAWRENCEVILLE PROVIDED SOME SUNSHINE APPEARS THERE THIS AFTERNOON. MORE CLOUDS FROM I-57 EAST AND FROM PEORIA NORTH AND SW AREAS FROM LINCOLN SW TO SEE MORE SUNSHINE THIS AFTERNOON WHERE DRY SLOT MOVING IN FROM MO. && .PREV DISCUSSION...COLD FRONT ON TARGET TO MOVE THROUGH ILLINOIS TODAY. SHOULD BE NEAR I-57 BY EARLY AFTERNOON...THEN NEAR I-70 BY EARLY EVENING. THIS FRONT WILL BE THE CONCERN OVER THE NEXT SEVERAL DAYS...AS IT IS EXPECTED TO STALL OUT ALONG THE OHIO RIVER VALLEY AND BECOME THE FOCUS FOR CONTINUED PRECIPITATION CHANCES... ESPECIALLY ACROSS SOUTHERN ILLINOIS. MODELS PAINTING HEALTHY RAINFALL AMOUNTS WITH THIS BOUNDARY THROUGH THE END OF THE WEEK...CHALLENGE IS HOW FAR NORTH TO BRING THE CHANCES. MODEL DIFFERENCES EXIST...ESPECIALLY IN THE QPF FIELD OFF THE GFS...WHICH APPEAR TO BE SUFFERING FROM CONTINUAL CONVECTIVE FEEDBACK PROBLEMS. WILL LEAN TOWARD THE ETA IN THIS RESPECT. GUIDANCE TEMPERATURES LOOKED REASONABLE...BUT DID SIDE ON THE COOL SIDE WITH THE PRECIPITATION EXPECTED OVER THE NEXT FEW DAYS IN THE SOUTHEAST. SHORT TERM...TODAY THROUGH SATURDAY... ELEVATED NOCTURNAL SHOWERS AND THUNDERSTORMS HAVE DIMINISHED IN INTESITY AS THEY TRACKED ACROSS ILLINOIS EARLY TODAY. THIS PRE-FRONTAL BATCH OF PRECIPITATION IS EXPECTED TO CLEAR EAST CENTRAL/SOUTHEAST ILLINOIS WITHIN THE NEXT COUPLE OF HOURS. SURFACE FRONT WILL EXPECTED TO MAKE IT TO THE I-70 CORRIDOR BY AROUND 00Z...THEN SAG SOUTH TOWARD THE OHIO RIVER VALLEY REGION BY OVERNIGHT TONIGHT. IT WILL BE DIFFICULT TO RECOVER ENOUGH INSTABILITY IN THE AIRMASS ACROSS WESTERN PORTIONS OF CENTRAL ILLINOIS BEFORE THE FRONT GOES THROUGH TO SEE ANY RAINFALL WITH IT. DIFFERENT STORY IN THE EAST/SOUTHEAST. HAVE MAINTAINED CHANCES POPS IN THOSE AREAS THIS AFTERNOON. SOUTHEAST AREAS IN A SLIGHT RISK FOR SEVERE WEATHER. THIS LOOKS GOOD...WITH ETA AND GFS IN AGREEMENT WITH SURFACE LI/S EXPECTED TO BE CLOSE TO -6 AND CAPES TO 1500 J/KG WITH PEAK HEATING THERE. SOUTHERN STREAM SHORTWAVE ENERGY IS PROGGED TO ACTIVATE THE FRONT ACROSS THE SOUTHERN PLAINS STATES AROUND MIDNIGHT TONIGHT...SHIFTING NORTH TOWARD THE OHIO RIVER VALLEY REGION DURING THE OVERNIGHT. ETA/NGM MODELS VERY SIMILAR IN THE QPF FIELDS. THIS IS WHERE GFS STARTS ITS FEEDBACK ISSUES...WITH A SHORTWAVE OVER NORTHEAST KANSAS AT 12Z THU...WHERE THE OTHER MODELS DO NOT. GFS ACTUALLY MAINTAINS THIS WAVE THROUGH IOWA DURING THE DAY THU...THEN MERGES IT INTO THE NORTHERN STREAM. ETA SHIFTS THE SHORTWAVE ENERGY FROM THE SOUTHERN PLAINS INTO INDIANA BY 00Z FRIDAY...WHICH MAY BE A BIT SLOW. BELIEVE BEST PCPN CHANCES WILL BE IN THE MORNING THU...WITH CHANCES TAPERING OFF DURING THE AFTERNOON. BEST CHANCES ACROSS SOUTHEAST PART OF CWA...BUT WILL BRING CHANCES AS FAR NORTH AS CENTRAL CWA. ANOTHER...MORE SIGNIFICANT WAVE MOVES OUT FROM THE SOUTHERN ROCKIES THURSDAY NIGHT. LEAD SHORTWAVE ENERGY AGAIN ACTIVATES THE FRONT. ETA HAS TRENDED FARTHER SOUTH WITH THE FRONTAL/LOW POSITION WITH THIS WAVE...SO AGAIN BEST CHANCES ACROSS SOUTH. TIMING FOR ILLINOIS LOOKS TO BE FRIDAY AND FRIDAY NIGHT. ADDING QPF VALUES AT THIS TIME LOOKS PRETTY OMINOUS...WITH THE POTENTIAL OF SIGNIFICANT RAINFALL ACROSS SOUTHERN ILLINOIS. WILL NEED TO MONITOR THIS. THE MOVEMENT OF THE MAIN SHORTWAVE WILL DICTATE THE DEPARTURE OF THE SURFACE LOW AND THE ASSOCIATED FRONTAL BOUNDARY. FOR NOW...WILL DROP RAIN CHANCES SATURDAY NIGHT. LONG TERM...SUNDAY THROUGH TUESDAY...MODELS CONTINUE TO ADVERTISE A SHIFT IN THE PATTERN ...WITH THE NORTHERN STREAM BECOMING THE MORE PREDOMINANT FEATURE ACROSS THE GREAT LAKES REGION. WITH AN UPPER LEVEL TROF IN PLACE THROUGH EARLY MONDAY...WILL LIKELY SEE COOL SPRING TIME TEMPERATURES THROUGH THE REMAINDER OF THE WEEKEND. CAN NOT RULE OUT SCATTERED SHOWER ACTIVITY...BUT FOR NOW LOOKS LIKE GREATER THREAT WILL BE FARTHER NORTH WITH THE SHORTWAVE ENERGY ROUNDING THE BASE OF THE UPPER TROF TO OUR NORTH. THE UPPER TROF IS FORECAST TO SHIFT INTO NEW ENGLAND TUESDAY... ALLOWING HEIGHTS TO RISE AND A WARMING TREND BY WEDNESDAY. && .ILX WATCHES/WARNINGS/ADVISORIES... IL...NONE. && $$ PLAHMER/HUETTL il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 230 PM CDT WED APR 21 2004 .DISCUSSION... MAIN CONCERN IS LARGE DISAGREEMENT IN SHORT TERM FORECAST BY GFS/ETA FOR PCPN TNGT AND INTO THURSDAY MRNG. HAVE LOOKED AT DVLPMNTL RUC20 WHICH HAS BEEN RIGHT ON RECENTLY IN TIMING AND COVERAGE OF PCPN. WILL GO FOR SLGT CHC IN PARTS OF W AND SW TNGT AS SYSTEM BRUSHES CWA. GFS APPEARS TO BE IN OVERDONE IN STRENGTH OF S/W AND COVERAGE OF RAIN. ALSO IN SHORT RANGE CANADIAN FAVORS DRY. HWVR DO FAVOR WETTER RUC20 THURSDAY NIGHT /FRIDAY. BELIEVE SUPPRESSION BY ETA TOO MUCH. THEN GOING INTO FRIDAY NIGHT/SATURDAY STRONGEST OF S/W AND WITH FNTL BNDRY INVOF CWA GOOD CHANCE FOR RAIN WITH ETA FINALLY AGREEING WITH WETTER MODEL RUNS. RUC20 IN GOOD AGREEMENT MOVING BOUNDARY/RAIN NEWRD. AIRMASS SHOWS LITTLE CHANGE OVER SHORT TERM FORECAST WITH HIGHS IN 60S AND LOWS IN 30S AND 40S. ON WEEKEND WEAK SYSTEM PASSES TO THE NORTH OF CWA WITH SLGT CHANCE FOR RAIN SUNDAY AFTN AND NIGHT. THEN UPPER RIDGE BUILD OVER CNTLR U.S AND WARMUP BEGINS NEXT WEEK. TUESDAY AND WEDNESDAY COULD BE VERY WARM. BETTER AGREEMENT THROUGH MODEL RUNS TODAY IN KEEPING STATE DRY. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ FORSTER ia AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE WICHITA KS 1000 PM CDT WED APR 21 2004 .DISCUSSION... TNGT: WEL-DEFINED SFC-850MB STNRY FRONT DRAPED IN W-E MANNER ACRS CNTRL OK TO CONT SERVING AS FOCUS FOR MAJOR TSRA DVLPMT/REDVLPMT FOR REST OF THE NGT. BOTH GFS80 & ETA80 DEPICT STNRY FRONT TRANSITIONING TO WARM FRONT WHICH, CSDR'G SUBTLE MID-LVL S/WV SPRINTING E OVER TX/OK PANHANDLE THIS EVE, MAKES SENSE. IN ADDITION, UPSTAIRS DIRECTIONAL DIVERGENCE INCRS AS NGT PROGRESSES. ALL REASONS DICTATE GOING FULL THROTTLE ON (+)TSRA ACRS SC & SE KS W/ RSLT'G QPFS INCR'D MARKEDLY TO 0.25-0.40" RANGE W/ GREATER QPF ASSIGNED TO OK-BDR'G COUNTIES OF SE KS WHERE CLOSER TO PROG'D POSIT- IONING OF SFC-850MB MSTR AXIS. ES ----------------------------------------------------------------------- .PREV DISCUSSION... MESO UPDATE CURRENTLY TWO AREAS OF CONVECTION ONGOING ASSOCIATED WITH TWO DIFFERENT MECHANISMS FIRST THE ACTIVITY OVER EASTERN OK IS RELATED TO STORMS THAT FIRED ALONG A DRY LINE AND WARM FRONT. THESE STORMS HAVE DEVELOPED A NORTH TO SOUTH ORIENTED LINE AND ARE TRACKING EAST. THE WARM FRONT FROM THIS AFTERNOON HAS PRETTY MUCH WASHED OUT INTO MORE OF A DEWPOINT GRADIENT. IT APPEARS STORMS ARE FIRING OVER NORTHERN OK IN RESPONSE TO STRONG LOW LEVEL MOISTURE CONVERGENCE. A SECOND AREA OF CONVECTION DEVELOPED OVER SW KS IN AN AREA SITUATED UNDER GOOD JET DYNAMICS PLUS GOOD UPSLOPE FLOW. THIS AREA IS ALSO EXPERIENCING QUITE A BIT OF LOW LEVEL MOISTURE CONVERGENCE VIA RUC ANALYSIS. WITH SFC WINDS AROUND 150-130 DEGREES, THERE IS PLENTY OF LOW LEVEL SHEAR TO SUPPORT ROTATION AND THUS THE TOR WARNINGS IN DDC'S AREA. THE MOST LIKELY LOCATION FOR CONVECTION OVER THE CWA CONTINUES TO BE THE SOUTHERN AND SOUTHEAST PORTION OF THE AREA. ANY STORM THAT MOVES INTO THE AREA WL HAVE PLENTY OF SHEAR TO SUPPORT ROTATION. THE LACK OF RICH LOW LEVEL MOISTURE MAY KEEP SOME OF THIS ACTIVITY ELEVATED AND THUS THE MAIN THREAT WOULD BE LARGE HAIL. LAWSON -------------------------------------------------------------------- .PREVIOUS DISCUSSION... MAIN FCST CONCERN IS TRYING TO FIGURE OUT CONVECTIVE TRENDS THE FIRST FEW PERIODS AS COMPLEX SET-UP UNDERWAY HAVE HIGHER CONFIDENCE IN THE EXTENDED VERIFYING COMPARED TO THE FIRST FEW DAYS AS THE NEAR TERM WL DEPEND HEAVILY ON SMALL SCALES FEATURES WHICH THE SHORT RANGE MODELS ARE HAVING TROUBLE WITH TNGT: CONFIDENCE IN POPS IS LOW FOR THIS PERIOD AS MUCH OF IT WL DEPEND ON HOW THINGS EVOLVE OVER THE NEXT FEW HOURS. AM CONFIDENT THAT SVR STORMS WL FIRE HERE SOON OVER CENTRAL AND EASTERN OKLAHOMA ALONG A WELL DEFINED WARM FRONT THAT HAS BEEN SLOWLY LIFTING NORTH THROUGH THE AFTERNOON. AM THINKING THE BULK OF THE ACTIVITY WL STAY SOUTH OF THE CWA BUT ATTM CU FIELD CORRELATED TO BETTER MOISTURE IS NOT TOO FAR SOUTH. SO WL AT LEAST NEED POPS FOR SE KS IN CASE SOME STUFF CREEPS INTO THIS AREA. ANOTHER AREA TO KEEP AN EYE ON WL BE OVER WESTERN KANSAS. THIS IS WHERE THE BUTTER UPPER DYNAMICS WL BE SITUATED, IE. THE LEFT EXIT REGION OF A STRONG JET. THIS FEATURE COUPLED WITH GOOD UPSLOPE MAY LEAD TO A CLUSTER OF STORMS DEVELOPING AND TRACKING EAST THROUGH THE NIGHT. DUE TO TO THIS SCENARIO, WL HAVE POPS CWA WIDE TNGT. THU-THU NGT: THU SHUD CONTINUE TO BE A ACTIVE DAY ACROSS THE REGION AS MORE SVR WX WL BE ON TAP. THU MAY NOT BE TOO MUCH DIFFERENT THAN TDAY'S SET UP, WITH TWO AREAS OF CONVECTIVE DEVELOPMENT. ONE ALONG THE WARM FRONT AND AGAIN NEAR THE BETTER UPPER DYNAMICS OVER WESTERN KANSAS. CONFIDENCE IS LOW ON WHERE THIS WARM FRONT WL BE LOCATED DUE TO HOW FAR SOUTH TNGT'S CONVECTION WL PUSH IT. FIRST GUESS WOULD BE THAT THE SOUTHERN TIER OF COUNTIES WL HAVE THE BEST SHOT FOR SVR STORMS. A MORE ORGANIZED MCS SHUD BE UNDER WAY ACROSS THE AREA THU NGT AS 850MB CONVERGENCE COUPLED WITH GOOD ISENTROPIC LIFT SET UP OVER THE AREA. AGAIN, THE BEST SHOT FOR SVR STORMS WOULD BE FOR LOCATIONS ACROSS THE SOUTHERN PORTION OF THE CWA, WHERE THE BETTER INSTABILITY WOULD BE SITUATED. FRI-SAT: COMPARED TO YESTERDAY'S RUNS THIS SYSTEM HAS SLOWED DOWN QUITE A BIT. THEREFORE WE ARE NOT OUT OF THE WOODS YET FOR CONVECTION ON FRI. BY 18Z FRI THE UPPER LOW SHUD BE SITUATED BACK OVER CO WITH AN INVERTED SFC TROUGH EXTENDED THROUGH SE KS/EASTERN OK. AGAIN, ISENTROPIC LIFT WL CONTINUE AND EVEN ENHANCE A BIT FRI. FEEL THE MAIN INHIBITOR TO SVR STORMS WOULD BE LACK OF INSTABILITY DUE TO PLENTY OF CLOUD COVER. SO WE MAY JUST SEE SOME SHRA AND -TSRA. EXPANDED POPS FOR SAT AS MOST OF CWA MAY BE UNDER THE RIGHT ENTRANCE REGION OF AN UPPER JET. PLUS SHUD BE A COLD POCKET ALOFT SLIDING OVER THE AREA. SUN-WED: JUST AS YESTERDAY, DID NOT CHANGE TOO MUCH AT ALL FROM THE PREV FCST. CONFIDENCE HAS INCREASED FROM YESTERDAY'S PACKAGE THAT THESE PERIODS WL BE DRY WITH NEAR NORMAL TEMPS. BY 00Z MON SFC RIDGE WL BE PLANTED OVER THE CENTRAL PLAINS. THIS PICTURE IS PAINTED BY ALL OF THE MED RANGE MODELS INCLUDING THE UK WHICH DOES LEAD TO SOME CONFIDENCE. AT THE UPPER LEVELS A BROAD PERSISTENT RIDGE LOOKS TO REMAIN IN PLACE OVER THE ROCKIES, SETTING UP A CLASSIC PNA PATTERN WHICH WL PERSIST IN TO THE MIDDLE OF NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... WICHITA 52 70 51 61 / 40 30 70 70 HUTCHINSON 51 67 50 61 / 50 40 70 60 NEWTON 52 68 51 62 / 40 30 70 60 ELDORADO 52 70 52 62 / 40 30 70 70 STROTHER FIELD 54 73 53 62 / 40 30 70 70 RUSSELL 48 61 45 55 / 50 50 70 60 GREAT BEND 50 63 47 56 / 50 50 70 60 SALINA 50 63 46 61 / 40 50 70 60 MCPHERSON 51 64 49 61 / 50 50 70 60 COFFEYVILLE 56 75 55 65 / 60 40 70 70 CHANUTE 53 71 53 64 / 50 40 70 70 IOLA 53 70 53 63 / 40 40 70 70 && .ICT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ 7/LAWSON ks AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE WICHITA KS 645 PM CDT WED APR 21 2004 .DISCUSSION... MESO UPDATE CURRENTLY TWO AREAS OF CONVECTION ONGOING ASSOCIATED WITH TWO DIFFERENT MECHANISMS FIRST THE ACTIVITY OVER EASTERN OK IS RELATED TO STORMS THAT FIRED ALONG A DRY LINE AND WARM FRONT. THESE STORMS HAVE DEVELOPED A NORTH TO SOUTH ORIENTED LINE AND ARE TRACKING EAST. THE WARM FRONT FROM THIS AFTERNOON HAS PRETTY MUCH WASHED OUT INTO MORE OF A DEWPOINT GRADIENT. IT APPEARS STORMS ARE FIRING OVER NORTHERN OK IN RESPONSE TO STRONG LOW LEVEL MOISTURE CONVERGENCE. A SECOND AREA OF CONVECTION DEVELOPED OVER SW KS IN AN AREA SITUATED UNDER GOOD JET DYNAMICS PLUS GOOD UPSLOPE FLOW. THIS AREA IS ALSO EXPERIENCING QUITE A BIT OF LOW LEVEL MOISTURE CONVERGENCE VIA RUC ANALYSIS. WITH SFC WINDS AROUND 150-130 DEGREES, THERE IS PLENTY OF LOW LEVEL SHEAR TO SUPPORT ROTATION AND THUS THE TOR WARNINGS IN DDC'S AREA. THE MOST LIKELY LOCATION FOR CONVECTION OVER THE CWA CONTINUES TO BE THE SOUTHERN AND SOUTHEAST PORTION OF THE AREA. ANY STORM THAT MOVES INTO THE AREA WL HAVE PLENTY OF SHEAR TO SUPPORT ROTATION. THE LACK OF RICH LOW LEVEL MOISTURE MAY KEEP SOME OF THIS ACTIVITY ELEVATED AND THUS THE MAIN THREAT WOULD BE LARGE HAIL. LAWSON -------------------------------------------------------------------- .PREVIOUS DISCUSSION... MAIN FCST CONCERN IS TRYING TO FIGURE OUT CONVECTIVE TRENDS THE FIRST FEW PERIODS AS COMPLEX SET-UP UNDERWAY HAVE HIGHER CONFIDENCE IN THE EXTENDED VERIFYING COMPARED TO THE FIRST FEW DAYS AS THE NEAR TERM WL DEPEND HEAVILY ON SMALL SCALES FEATURES WHICH THE SHORT RANGE MODELS ARE HAVING TROUBLE WITH TNGT: CONFIDENCE IN POPS IS LOW FOR THIS PERIOD AS MUCH OF IT WL DEPEND ON HOW THINGS EVOLVE OVER THE NEXT FEW HOURS. AM CONFIDENT THAT SVR STORMS WL FIRE HERE SOON OVER CENTRAL AND EASTERN OKLAHOMA ALONG A WELL DEFINED WARM FRONT THAT HAS BEEN SLOWLY LIFTING NORTH THROUGH THE AFTERNOON. AM THINKING THE BULK OF THE ACTIVITY WL STAY SOUTH OF THE CWA BUT ATTM CU FIELD CORRELATED TO BETTER MOISTURE IS NOT TOO FAR SOUTH. SO WL AT LEAST NEED POPS FOR SE KS IN CASE SOME STUFF CREEPS INTO THIS AREA. ANOTHER AREA TO KEEP AN EYE ON WL BE OVER WESTERN KANSAS. THIS IS WHERE THE BUTTER UPPER DYNAMICS WL BE SITUATED, IE. THE LEFT EXIT REGION OF A STRONG JET. THIS FEATURE COUPLED WITH GOOD UPSLOPE MAY LEAD TO A CLUSTER OF STORMS DEVELOPING AND TRACKING EAST THROUGH THE NIGHT. DUE TO TO THIS SCENARIO, WL HAVE POPS CWA WIDE TNGT. THU-THU NGT: THU SHUD CONTINUE TO BE A ACTIVE DAY ACROSS THE REGION AS MORE SVR WX WL BE ON TAP. THU MAY NOT BE TOO MUCH DIFFERENT THAN TDAY'S SET UP, WITH TWO AREAS OF CONVECTIVE DEVELOPMENT. ONE ALONG THE WARM FRONT AND AGAIN NEAR THE BETTER UPPER DYNAMICS OVER WESTERN KANSAS. CONFIDENCE IS LOW ON WHERE THIS WARM FRONT WL BE LOCATED DUE TO HOW FAR SOUTH TNGT'S CONVECTION WL PUSH IT. FIRST GUESS WOULD BE THAT THE SOUTHERN TIER OF COUNTIES WL HAVE THE BEST SHOT FOR SVR STORMS. A MORE ORGANIZED MCS SHUD BE UNDER WAY ACROSS THE AREA THU NGT AS 850MB CONVERGENCE COUPLED WITH GOOD ISENTROPIC LIFT SET UP OVER THE AREA. AGAIN, THE BEST SHOT FOR SVR STORMS WOULD BE FOR LOCATIONS ACROSS THE SOUTHERN PORTION OF THE CWA, WHERE THE BETTER INSTABILITY WOULD BE SITUATED. FRI-SAT: COMPARED TO YESTERDAY'S RUNS THIS SYSTEM HAS SLOWED DOWN QUITE A BIT. THEREFORE WE ARE NOT OUT OF THE WOODS YET FOR CONVECTION ON FRI. BY 18Z FRI THE UPPER LOW SHUD BE SITUATED BACK OVER CO WITH AN INVERTED SFC TROUGH EXTENDED THROUGH SE KS/EASTERN OK. AGAIN, ISENTROPIC LIFT WL CONTINUE AND EVEN ENHANCE A BIT FRI. FEEL THE MAIN INHIBITOR TO SVR STORMS WOULD BE LACK OF INSTABILITY DUE TO PLENTY OF CLOUD COVER. SO WE MAY JUST SEE SOME SHRA AND -TSRA. EXPANDED POPS FOR SAT AS MOST OF CWA MAY BE UNDER THE RIGHT ENTRANCE REGION OF AN UPPER JET. PLUS SHUD BE A COLD POCKET ALOFT SLIDING OVER THE AREA. SUN-WED: JUST AS YESTERDAY, DID NOT CHANGE TOO MUCH AT ALL FROM THE PREV FCST. CONFIDENCE HAS INCREASED FROM YESTERDAY'S PACKAGE THAT THESE PERIODS WL BE DRY WITH NEAR NORMAL TEMPS. BY 00Z MON SFC RIDGE WL BE PLANTED OVER THE CENTRAL PLAINS. THIS PICTURE IS PAINTED BY ALL OF THE MED RANGE MODELS INCLUDING THE UK WHICH DOES LEAD TO SOME CONFIDENCE. AT THE UPPER LEVELS A BROAD PERSISTENT RIDGE LOOKS TO REMAIN IN PLACE OVER THE ROCKIES, SETTING UP A CLASSIC PNA PATTERN WHICH WL PERSIST IN TO THE MIDDLE OF NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... WICHITA 52 70 51 61 / 40 30 70 70 HUTCHINSON 51 67 50 61 / 50 40 70 60 NEWTON 52 68 51 62 / 40 30 70 60 ELDORADO 52 70 52 62 / 40 30 70 70 STROTHER FIELD 54 73 53 62 / 40 30 70 70 RUSSELL 48 61 45 55 / 50 50 70 60 GREAT BEND 50 63 47 56 / 50 50 70 60 SALINA 50 63 46 61 / 40 50 70 60 MCPHERSON 51 64 49 61 / 50 50 70 60 COFFEYVILLE 56 75 55 65 / 60 40 70 70 CHANUTE 53 71 53 64 / 50 40 70 70 IOLA 53 70 53 63 / 40 40 70 70 && .ICT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ 7/LAWSON ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 552 PM EST WED APR 21 2004 WILL DO AN EARLY UPDATE TO REMOVE REST OF THIS AFTERNOON PERIOD. LATEST RDR IMAGERY SHOWS NOTHING HAPPENING ATTM JUST HIGH OVERCAST. LATEST 18Z MESOETA SUGGESTS A LINE OF CONVECTION WILL FORM OVR THE HIR TERRAIN OF CNTRL PA AND MOVE EAST AS THE EVENING PROGRESSES. IT SUGGESTS THAT SOME OF THAT ACTIVITY MAY SKIRT FAR NRN WASH/FDK COUNTIES MD. BUT AS OF RIGHT NOW CCX RADAR ONLY SHOWS AN ISOLD SHRA OVER INDIANA CTY. BEST CHANCE OF ANYTHING IT WOULD BE FAR NRN COUNTIES. REST OF THE AREA THINK TSTM CHANCES ARE PRETTY REMOTE. A WEAKENING LINE OF SHRAS IS FCST TO MOVE INTO FAR NWRN COUNTIES AFTER 09Z. WILL LIKELY REMOVE POPS WITH SECOND UPDATE LATER THIS EVENING. ROSA .SHORT TERM (TONIGHT THROUGH THURSDAY): ...SLIGHT RISK OF SEVERE THUNDERSTORMS FROM OKV-->DCA NORTHWARD THIS AFTERNOON AND EVENING... WATER VAPOR LOOP SHOWS A MIDLEVEL WAVE LIFTING NORTHEAST ACROSS WISCONSIN...WITH A SHEARING WAVE APPROACHING THE NORTHERN GREAT LAKES FROM THE NORTHWEST. MEANWHILE...A SHEARED VORTICITY AXIS STRETCHES FROM NEW ENGLAND CURVING INTO THE TENNESSEE VALLEY. ACARS 250-400MB WIND SPEED OBSERVATIONS SHOW A 125KT JET FROM CALIFORNIA INTO TEXAS...WITH THE JET STREAM LIFTING ACROSS THE GREAT LAKES AND EAST INTO NORTHERN NEW ENGLAND. 11Z SURFACE ANALYSIS SHOWS A DUAL LOW STRUCTURE OVER THE WESTERN GREAT LAKES...WITH A WARM/STATIONARY BOUNDARY STRETCHING ACROSS THE EASTERN GREAT LAKES SOUTHEAST ACROSS THE MID ATLANTIC REGION. THE NEXT COLD FRONT IS LOCATED FROM THE MIDWEST INTO THE PLAINS. MARINE LAYER FAILED TO INVADE OVERNIGHT...LEAVING THE FORECAST AREA UNDER PARTLY CLOUDY SKIES THIS AFTERNOON. THUSLY...INSTABILITY IS HIGHER THAN EXPECTED YESTERDAY. ETA/RUC SHOW MODEST CAPE (1500-2000 J/KG). THIS LOOKS A BIT OVERDONE WITH ETA BOUNDARY LAYER DEWPOINTS A BIT TOO HIGH. STILL...WILL HAVE ENOUGH INSTABILITY AROUND THIS AFTERNOON JUDGING FROM THE KIAD AND REGIONAL ACARS SOUNDINGS FOR THUNDERSTORM DEVELOPMENT. LOOK OF THE MIDLEVEL CLOUDS ON THE VISIBLE LOOP NEAR THE DELMARVA AND TO OUR WEST CONFIRM THE INSTABILITY ALOFT. GIVEN INITIATION OF THUNDERSTORMS...THE MESOSCALE ENVIRONMENT IS SUPPORTIVE OF SOME STRONGER STORMS. 850-700MB LAPSE RATES ON AREA SOUNDINGS ARE DRY ADIABATIC...WITH THE RUC MODEL SHOWING THE ADVECTION OF 7-8 C/KM 700-500MB LAPSE RATES NORTHEAST FROM THE TENNESSEE VALLEY. SHEAR IN THE 0-1 KM LAYER IS PARTICULARLY ENHANCED ALONG AND NORTH OF THE SURFACE BOUNDARY (WHICH EXTENDS FROM NEAR CBE-->CHO AND SOUTH OF EZF AS OF 18Z MESOANALYSIS)...WHILE 0-6KM SHEAR IS ABOUT 35 KTS. WETBULB ZERO HEIGHTS NEAR 9KFT WOULD SUPPORT A HAIL THREAT GIVEN ORGANIZED CONVECTION AS WELL. AS THE WESTERN CONUS JET CONTINUES TO PUSH EASTWARD INTO THE PLAINS...LOWERING HEIGHTS ACROSS THE OHIO VALLEY WILL SUPPORT THE COLD FRONTAL BOUNDARY SAGGING IN FROM THE MIDWEST LATE TONIGHT AND TOMORROW. THIS WILL BRING AN INCREASE IN CLOUD COVER AND A FOCUS FOR PRECIPITATION. ROGOWSKI && .LONG TERM...THURSDAY NIGHT THROUGH TUESDAY NIGHT...MODELS STILL SHOWING A WEAK COLD FRONT STALLING OUT ACROSS THE REGION THURSDAY NIGHT/FRIDAY WITH A WAVE DEVELOPING AND MOVING ALONG THE FRONT FRIDAY. THERE STILL LOOKS TO BE SOME INSTABILITY WILL EXPAND THUNDER IN ACROSS THE FA. THE MODELS THEN BRING IN HIGH PRESSURE MOVING DOWN FROM THE GREAT LAKES SATURDAY PUSHING THE COLD FRONT TO THE SOUTH OF OUR CWA. SO WILL CONTINUE THE TREND OF DRIER WITH MORE SEASONABLE TEMPS FOR SAT. NEXT TROUGH OVR THE CENTRAL U.S. IS THEN PROGGED TO PUSH EAST WITH A ANOTHER COLD FRONT MOVING OVER THE REGION SUNDAY/MONDAY. DRIER AND IMPROVING CONDITIONS FOR TUESDAY. ND && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. $$ md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 240 PM EST WED APR 21 2004 .SHORT TERM (TONIGHT THROUGH THURSDAY): ...SLIGHT RISK OF SEVERE THUNDERSTORMS FROM OKV-->DCA NORTHWARD THIS AFTERNOON AND EVENING... WATER VAPOR LOOP SHOWS A MIDLEVEL WAVE LIFTING NORTHEAST ACROSS WISCONSIN...WITH A SHEARING WAVE APPROACHING THE NORTHERN GREAT LAKES FROM THE NORTHWEST. MEANWHILE...A SHEARED VORTICITY AXIS STRETCHES FROM NEW ENGLAND CURVING INTO THE TENNESSEE VALLEY. ACARS 250-400MB WIND SPEED OBSERVATIONS SHOW A 125KT JET FROM CALIFORNIA INTO TEXAS...WITH THE JET STREAM LIFTING ACROSS THE GREAT LAKES AND EAST INTO NORTHERN NEW ENGLAND. 11Z SURFACE ANALYSIS SHOWS A DUAL LOW STRUCTURE OVER THE WESTERN GREAT LAKES...WITH A WARM/STATIONARY BOUNDARY STRETCHING ACROSS THE EASTERN GREAT LAKES SOUTHEAST ACROSS THE MID ATLANTIC REGION. THE NEXT COLD FRONT IS LOCATED FROM THE MIDWEST INTO THE PLAINS. MARINE LAYER FAILED TO INVADE OVERNIGHT...LEAVING THE FORECAST AREA UNDER PARTLY CLOUDY SKIES THIS AFTERNOON. THUSLY...INSTABILITY IS HIGHER THAN EXPECTED YESTERDAY. ETA/RUC SHOW MODEST CAPE (1500-2000 J/KG). THIS LOOKS A BIT OVERDONE WITH ETA BOUNDARY LAYER DEWPOINTS A BIT TOO HIGH. STILL...WILL HAVE ENOUGH INSTABILITY AROUND THIS AFTERNOON JUDGING FROM THE KIAD AND REGIONAL ACARS SOUNDINGS FOR THUNDERSTORM DEVELOPMENT. LOOK OF THE MIDLEVEL CLOUDS ON THE VISIBLE LOOP NEAR THE DELMARVA AND TO OUR WEST CONFIRM THE INSTABILITY ALOFT. GIVEN INITIATION OF THUNDERSTORMS...THE MESOSCALE ENVIRONMENT IS SUPPORTIVE OF SOME STRONGER STORMS. 850-700MB LAPSE RATES ON AREA SOUNDINGS ARE DRY ADIABATIC...WITH THE RUC MODEL SHOWING THE ADVECTION OF 7-8 C/KM 700-500MB LAPSE RATES NORTHEAST FROM THE TENNESSEE VALLEY. SHEAR IN THE 0-1 KM LAYER IS PARTICULARLY ENHANCED ALONG AND NORTH OF THE SURFACE BOUNDARY (WHICH EXTENDS FROM NEAR CBE-->CHO AND SOUTH OF EZF AS OF 18Z MESOANALYSIS)...WHILE 0-6KM SHEAR IS ABOUT 35 KTS. WETBULB ZERO HEIGHTS NEAR 9KFT WOULD SUPPORT A HAIL THREAT GIVEN ORGANIZED CONVECTION AS WELL. AS THE WESTERN CONUS JET CONTINUES TO PUSH EASTWARD INTO THE PLAINS...LOWERING HEIGHTS ACROSS THE OHIO VALLEY WILL SUPPORT THE COLD FRONTAL BOUNDARY SAGGING IN FROM THE MIDWEST LATE TONIGHT AND TOMORROW. THIS WILL BRING AN INCREASE IN CLOUD COVER AND A FOCUS FOR PRECIPITATION. ROGOWSKI && .LONG TERM...THURSDAY NIGHT THROUGH TUESDAY NIGHT...MODELS STILL SHOWING A WEAK COLD FRONT STALLING OUT ACROSS THE REGION THURSDAY NIGHT/FRIDAY WITH A WAVE DEVELOPING AND MOVING ALONG THE FRONT FRIDAY. THERE STILL LOOKS TO BE SOME INSTABILITY WILL EXPAND THUNDER IN ACROSS THE FA. THE MODELS THEN BRING IN HIGH PRESSURE MOVING DOWN FROM THE GREAT LAKES SATURDAY PUSHING THE COLD FRONT TO THE SOUTH OF OUR CWA. SO WILL CONTINUE THE TREND OF DRIER WITH MORE SEASONABLE TEMPS FOR SAT. NEXT TROUGH OVR THE CENTRAL U.S. IS THEN PROGGED TO PUSH EAST WITH A ANOTHER COLD FRONT MOVING OVER THE REGION SUNDAY/MONDAY. DRIER AND IMPROVING CONDITIONS FOR TUESDAY. ND && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. $$ md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 950 AM EST WED APR 21 2004 ...SCATTERED THUNDERSTORMS WITH POSSIBLE GUSTY WINDS AND SMALL HAIL POSSIBLE THIS AFTERNOON... WATER VAPOR LOOP SHOWS A MIDLEVEL WAVE LIFTING NORTHEAST ACROSS WISCONSIN...WITH A SHEARING WAVE APPROACHING THE NORTHERN GREAT LAKES FROM THE NORTHWEST. MEANWHILE...A SHEARED VORTICITY AXIS STRETCHES FROM NEW ENGLAND CURVING INTO THE CENTRAL GULF STATES. ACARS 250-400MB WIND SPEED OBSERVATIONS SHOW A 125KT JET FROM CALIFORNIA INTO TEXAS...WITH THE JET STREAM LIFTING ACROSS THE GREAT LAKES AND EAST INTO NORTHERN NEW ENGLAND. 11Z SURFACE ANALYSIS SHOWS A DUAL LOW STRUCTURE OVER THE WESTERN GREAT LAKES...WITH A WARM/STATIONARY BOUNDARY STRETCHING ACROSS THE EASTERN GREAT LAKES SOUTHEAST ACROSS THE MID ATLANTIC REGION. THE NEXT COLD FRONT IS LOCATED FROM THE MIDWEST INTO THE PLAINS. WITH OBSERVED PRESSURE FALLS OF 2-3MB ACROSS THE NORTHERN GREAT LAKES REGION TOWARDS THE HUDSON BAY...EXPECT HIGH PRESSURE LOCATED OVER NEW ENGLAND TO GRADUALLY SLIDE EASTWARD TODAY. THIS SHOULD MAINTAIN AN EAST-SOUTHEAST FLOW...PARTICULARLY ACROSS THE METRO REGION...SLOWING THE NORTHWARD PROGRESS OF THE SURFACE BOUNDARY THIS AFTERNOON. MEANWHILE...THE TAIL OF THE VORTICITY AXIS OVER THE LOWER TENNESSEE VALLEY SHOULD LIFT INTO THE MOUNTAINS LATE THIS AFTERNOON. MARINE LAYER FAILED TO INVADE OVERNIGHT...LEAVING THE FORECAST AREA UNDER PARTLY CLOUDY SKIES. THUSLY...INSTABILITY IS HIGHER THAN EXPECTED YESTERDAY. ETA/RUC SHOW MODEST CAPE (1500-2000 J/KG). THIS LOOKS A BIT OVERDONE WITH ETA BOUNDARY LAYER DEWPOINTS A BIT TOO HIGH. STILL...WILL HAVE ENOUGH INSTABILITY AROUND THIS AFTERNOON JUDGING FROM THE KIAD AND REGIONAL ACARS SOUNDINGS FOR THUNDERSTORM DEVELOPMENT. LOOK OF THE MIDLEVEL CLOUDS ON THE VISIBLE LOOP NEAR THE DELMARVA AND TO OUR WEST CONFIRM THE INSTABILITY ALOFT. GIVEN INITIATION OF THUNDERSTORMS...THE MESOSCALE ENVIRONMENT IS SUPPORTIVE OF SOME STRONGER STORMS. 850-700MB LAPSE RATES ON AREA SOUNDINGS ARE DRY ADIABATIC...WITH THE RUC MODEL SHOWING THE ADVECTION OF 7-8 C/KM 700-500MB LAPSE RATES NORTHEAST FROM THE TENNESSEE VALLEY. SHEAR IN THE 0-1 KM LAYER IS PARTICULARLY ENHANCED ALONG AND NORTH OF THE SURFACE BOUNDARY...WHILE 0-6KM SHEAR IS ABOUT 35 KTS. WETBULB ZERO HEIGHTS NEAR 9KFT WOULD SUPPORT A HAIL THREAT GIVEN ORGANIZED CONVECTION AS WELL. GIVEN A LACK OF LOW LEVEL CLOUDS...TEMPERATURES WILL BE ABLE TO TOP OUT IN THE 70S AND 80S. WINDS ARE EXPECTED TO REMAIN SOUTHEAST NORTH OF THE BOUNDARY...WITH MORE OF A SOUTHERLY COMPONENT ACROSS THE SOUTHERN ZONES LATER THIS AFTERNOON. UPDATED GRIDS ALREADY SENT...ZFP/EOL AND GRID DERIVED PRODUCTS OUT SHORTLY. ROGOWSKI && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. $$ md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1010 PM EDT WED APR 21 2004 .DISCUSSION... .SHORT TERM... 00Z RAOBS/WV LOOP AND RUC ANALYSIS SHOW SPLIT FLOW ACRS NAMERICA WITH FA INFLUENCED BY NRN BRANCH TROF. SHRTWV NOTED OVER THE CNTRL GREAT LAKES MOVING ENEWD WITH ASSOCIATED SFC LO IN QUEBEC HAS TAKEN DEEP MSTR/MOST PCPN OUT OF THE FA WITH IT...BUT BKN-OVC CLD LINGERS ACRS THE FA WITH TEMPS MAINLY 38-45 AND DWPTS 35-41. ANOTHER TRAILING SHRTWV/SFC COLD FNT/LINE OF SCT -SHRA MOVING THRU WRN LK SUP AND APRCHG THE WRN FA ATTM. SOME DRIER AIR IS FOLLOWING THE FNT INTO FAR WRN LK SUP AND IS APRNT ON 00Z INL SDNG BLO INVRN BASE AT H75...AND SFC DWPTS FALLING TOWARD 25 IN THAT AREA AND DOWN INTO THE TEENS FARTHER N OVER NW ONTARIO. BUT SC-BKN SC LINGERING ACRS THE MN ARROWHEAD AS INL SDNG SHOWS HI RH AT TOP OF DEEP MIXED LYR BLO HI INVRN BASE. MAIN FCST CONCERNS THIS PACKAGE ARE CLD/PCPN TRENDS AND TMIN FCST. BOTH 00Z RUC/18Z ETA SHOW LEAD SHRTWV OVER THE CNTRL GRT LKS PUSHING ENE INTO SE CAN OVERNGT...WITH TRAILING SHRTWV MOVING E TO NR ANJ BY 12Z. RISING HGTS/DNVA/UPR CNVGC/H85-5 QVECTOR DVGC MORE ACYC LLVL FLOW PROGGED TO OVERSPREAD THE FA IN THE WAKE OF THE SHRTWV/COLD FROPA. THE 18Z ETA SHOWED A LOW INVRN DVLPG OVERNGT IN THE WAKE OF THE FROPA AND INDICATED LO CLD WOULD FORM WITH MSTR TRAPPED BLO THE INVRN...BUT A COMPARISON OF THE 18Z ETA F6 SDNG FOR INL AND THE OBSVD SDNG SHOWS THE ETA FCST THE INVRN HGT ABOUT 175MB TOO LO AT THAT SPOT. THE RUC SDNG FOR INL IS MUCH MORE REPRESENTATIVE OF THE DRY AIRMASS OBSVD UPSTREAM. ALTHOUGH THE VIGOROUS NEGATIVE DYNAMICS WL TEND TO LOWER THE INVRN AND PASSAGE OF THE AIRMASS OVER LK SUP OVERNGT WL ALLOW SOME MOISTENING/LK CLD TO DVLP UNDER THIS INVRN... HAVE TENDED CLOSER TO THE RUC FOR FCST DETAILS. RUC SHOWS SFC COLD FNT CLRG MNM ARND 06Z...WITH DRYING AT H925-85 FOLLOWING PASSAGE OF BNDRY. HAVE OPTED TO RETAIN MENTION OF SCT -SHRA UNTIL FNT CLEAR A POINT...THEN WENT WITH SOME DCRS IN CLD COVER. THINK SC UNDER THE LWRG INVRN WL BE MOST PERSISTENT OVER THE HIER TERRAIN OF THE NCNTRL ZNS WHERE NNE FLOW UPSLOPES AND RUC H925-85 RH IS HIER. HAVE REJECTED ETA IDEA OF LGT -SN/DZ FALLING OVER THE HIER TERRAIN HERE WITH LLVL AIR TOO DRY AND FLOW MORE ACYC. TEMPS WL BE LOWEST OVER THE INTERIOR FAR WRN ZNS WHERE THE NE FLOW MAY BE ABLE TO DECOUPLE AND SKIES CAN CLEAR FOR A LONGER TIME. EXPECT TMINS AT THESE SPOTS TO APRCH UPSTREAM DWPTS ARND 25. KC .LONG TERM... COOL CANADIAN HIGH SETTLING IN OVER LAKE SUPERIOR AND MIDDAY 850 MB TEMPS OF -2C SOUTH TO -4C NORTH SHOULD KEEP TEMPS IN LOW 40S NORTH ALONG THE LAKE SUPERIOR SHORE TO LOW 50S ALONG THE WI BORDER UNDER FULL SUN. DEWPTS QUITE LOW (TEENS) UNDER THE UPSTREAM HIGH OVER WRN ONTARIO. AS SFC RIDGE SETTLES OVERHEAD THU NIGHT...EXPECT TEMPS TO PLUMMET UNDER PRIME RADIATIONAL COOLING CONDS. TEENS SHOULD BE EASILY REACHED OVER THE USUAL INTERIOR COLD SPOTS WITH A RECORD LOW POSSIBLE AT THE MARQUETTE FCST OFFICE. PASSAGE OF CDFNT ASSOC WITH NRN BRANCH SHORTWAVE LOOKS TO BE LATE FRI AS 850 MB TEMPS DROP TO -8C TO -9C OVER LAKE SUPERIOR IN ITS WAKE. WITH PWATS OF A QUARTER INCH OR LESS UPSTREAM OVER SRN CANADA EXPECT FRONTAL PASSAGE TO BE DRY WITH LTL IN WAY OF INCREASE IN CLOUDS. 850 MB TEMPS OF 0 TO -2C AHEAD OF TROUGH SHOULD YIELD HIGHS ON FRI IN THE UPPER 40S TO LOW 50S. SATURDAY...WITH 8H RDG BUILDING IN STRONG OVER THE AREA AND DAYTIME 8H TEMPS REBOUNDING TO -1 TO -4C PER ETA...HAVE BUMPED UP HIGHS TO MID TO UPPER 40S NORTH TO MID 50S SOUTH GIVEN EXPECTED FULL SUN. EXTENDED (SUN-WED)...UKMET...ECMWF AND CANADIAN TO VARYING DEGREES HAVE ALL TRENDED TOWARD GFS SOLN OF BRINGING SRN STREAM WAVE NORTHWARD INTO GREAT LAKES BY SUN. CANADIAN AND GFS ENSEMBLES ALSO HINT AT THIS IDEA. HOWEVER...BELIEVE STRENGTH OF CANADIAN SFC HIGH OVER AREA WILL TEND TO DELAY ARRIVAL AND SHORT WAVE AND GENLY KEEP MOST OF ENERGY WELL SOUTHEAST. STILL WITH 5H TROUGH AND ASSOC WK COLD POOL OF -22C TEMPS OVRHD...HAVE INCLUDED LOW CHC POPS FOR ENTIRE CWA ON SUN. NRN STREAM SHORT WAVE AND SECONDARY TROUGH MOVING THROUGH ON SUN NIGHT WILL ALSO WARRANT KEEPING LOW CHC POPS IN FOR SUN NIGHT AS WELL. WITH RDGG BUILDING BACK IN OVER AREA ON MON BEHIND SHRTWV...LOOK FOR DRIER CONDITIONS...ALTHOUGH 8H TEMPS AROUND -5C LINGERING IN THE OVER AREA MAY KEEP IN SOME LOW CLOUDS...ESPECIALLY IN THE MORNING. GRADUAL WARMING EXPECTED TUE AS AS A BLEND OF OPERATIONAL MODELS AND ENSEMBLE MEANS WOULD INDICATE 8H TEMPS OF 2-5C OVER AREA BY MIDDAY...WHICH SHOULD YIELD INLAND HIGHS IN MID 50S NORTH TO LOW 60S SOUTH. STRONGER SW FLOW ON WED AHD OF ADVANCING PLAINS TROUGH REALLY RAMPS UP 8H TEMPS TO 12 TO 14C BY MIDDAY. WITH NEARLY FULL SUN...EXPECT TEMPS IN LOW TO MID 70S. VOSS && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1152 AM EDT WED APR 21 2004 .UPDATE... UPDATE FOCUS IS WITH THUNDERSTORM AND SEVERE POTENTIAL FOR THIS AFTERNOON. WATER VAPOR LOOP SHOWS SHORTWAVE LIFTING INTO WESTERN WISCONSIN...WITH SURFACE ANALYSIS SHOWING COLD FRONT OVER WISCONSIN/ILLINOIS. PREFRONTAL TROUGH CAN BE PICKED OUT OF OBS OVER WESTERN INDIANA. A NUMBER OF SHOWERS HAVE DEVELOPED IN AN 850MB THETA-E RIDGE OVER INDIANA/OHIO INTO EASTERN LOWER/SOUTHERN ONTARIO. HOWEVER BEHIND THIS RIDGE THE LOW CLOUDS HAVE THINNED OUT...WITH MAINLY CIRRUS ACROSS SOUTHWEST LOWER. QUESTION FOR TODAY IS WITH DESTABILIZATION...AND FOCUS/DEVELOPMENT PLACEMENT AND TIMING. EVEN WITH SOME SHOWERS THIS MORNING ACROSS SOUTHEAST MICHIGAN...ETA/RUC CONTINUE TO SHOW US DESTABILIZING AHEAD OF THE COLD FRONT. THE ETA IS MORE GUNG-HO WITH CAPE THAN THE RUC...SURFACE BASED CAPE OF 1500 J/KG ETA COMPARED TO 600J/KG RUC /ETA MIXED LAYER CAPE IS MORE REASONABLE AROUND 1000J/KG/. MODIFIED 12Z DTX SOUNDING FOR 71/56 YIELDS 1000J/KG. THIS MORNING DEWPOINTS WERE ONLY INTO THE 50S ACROSS THE SOUTHERN LAKES AND OHIO/TENNESSEE VALLEYS. HOWEVER THROUGH 15Z DEWPOINTS HAVE CLIMBED INTO THE LOWER 60S AS FAR NORTH AS SOUTHERN ILLINOIS/INDIANA. EVEN WITH MORNING PRECIP /SHOWERS WHICH WERE RATHER SCATTERED/...STRONG SOUTHWEST FLOW AHEAD OF THE FRONT SHOULD BE ABLE TO PULL SOME BETTER INSTABILITY INTO THE REGION. IN ADDITION WITH SOME /ALBEIT LIMITED/ INSOLATION ACROSS LOWER MICHIGAN WITH THINNER CLOUDS...WE SHOULD BE ABLE TO DESTABILIZE ENOUGH FOR AFTERNOON CONVECTION. AS FOR THE WIND FIELD...SURFACE WARM FRONT HAS LIFTED NORTH OF THE CWA...AND LOW-LEVEL HELICITIES HAVE DIMINISHED. THERE IS STILL SOME LOW-LEVEL TURNING IN THE WIND FIELD PER RUC/ETA FORECAST HODOGRAPHS /HELICITIES NEAR 100M2/S2/. HOWEVER UPSTREAM SURFACE FLOW REMAINS MAINLY OUT OF THE SOUTHWEST. SOME STATIONS UPSTREAM /VPZ/GSH/AZO/ HAVE BACKED MORE TO THE SOUTH...WHICH LENDS SUPPORT TO THE ETA/RUC PROFILES. STRONG LOW-LEVEL JET AXIS HAS WEAKENED AND SHIFTED EAST /FROM 52KTS AT 1KFT PER DTX RAOBS AT 11Z TO 30KTS AT 2KFT PER DTX VWP AT 15Z/. HOWEVER...ETA/RUC CONTINUE TO SHOW 40KTS AT 850MB/50KTS 700MB/60KTS 500MB SPREADING BACK IN AHEAD OF THE FRONT THIS AFTERNOON. SHEAR FIELD WOULD INDICATE A MULTICELLULAR CONVECTIVE MODE WITH LEWPS/BOWS...BUT WITH INSTABILITY MARGINAL. SOME CONVECTION ACTUALLY BEGINNING TO DEVELOP ALONG COLD FRONT OVER EASTERN WISCONSIN SINCE 15Z. A FINE LINE IS APPARENT ON VISIBLE SATELLITE AND RADAR ACROSS WISCONSIN/NORTHERN ILLINOIS...A GOOD SIGN OF CONVERGENCE ALONG THE COLD FRONT. WITH THIS FOCUSING MECHANISM APPROACHING...SEVERE POTENTIAL DEPENDS ON THE AMOUNT OF INSTABILITY AVAILABLE AS THE FRONT MOVES INTO THE STATE. GIVEN INCREASING DEWPOINTS/SURFACE TEMPERATURES AND SOME SUN...WILL KEEP THE SLIGHT CHANCE OF SEVERE WEATHER GOING FOR THE AFTERNOON. CONSIDERING LIMITING FACTORS OF CLOUD COVER/ONGOING SHOWERS AND THEIR IMPACT ON DESTABILIZATION...IT WILL BE INTERESTING TO SEE HOW THIS EVENT EVOLVES. && BRAVENDER .PREV DISCUSSION...402 AM EDT WED APR 21 2004 A POTENT SHORT WAVE TROUGH IS SITUATED OVER THE UPPER MISSISSIPPI VALLEY PER WATER VAPOR IMAGERY. AN ASSOCIATED SURFACE LOW IS CENTERED OVER SOUTHEAST MINNESOTA...WITH A TRAILING WARM FRONT EXTENDING INTO THE SOUTHERN GREAT LAKES...ROUGHLY FROM MKG TO TOL PER 07Z SURFACE OBS. AREA RADAR DATA SHOWS THAT MOST OF THE CONVECTION ASSOCIATED WITH THE WARM FRONT HAS LIFTED WELL NORTH OF THE FORECAST AREA...ON THE NOSE OF A 60 KT LOW LEVEL JET ORIENTED AHEAD OF THE SURFACE LOW AND TRAILING COLD FRONT. THE SHORT WAVE TROUGH WILL LIFT INTO NW LOWER MI BY THIS EVENING...SENDING THE ASSOCIATED SURFACE LOW WELL NORTHEAST OF LAKE HURON AND ALLOWING THE WARM FRONT TO CLEAR SE MICHIGAN BY AFTERNOON. THE ASSOCIATED COLD FRONT WILL PASS THROUGH SE MICHIGAN BETWEEN 21Z AND 00Z TODAY. THUNDERSTORMS CHANCES AND SEVERE WEATHER POTENITAL TODAY ARE THE MAIN FORECAST CONCERNS THIS PACKAGE. THE CHANCES FOR THUNDERSTORMS WILL BE RATHER COMPLEX TODAY AS THERE ARE SOME BIG DIFFERENCES WITH RESPECT TO THE LOCATION OF THE MAIN INSTABILITY AXIS AHEAD OF THE FRONTAL BOUNDARY. WOULD EXPECT CONVECTION TO DEVELOP LATER THIS MORNING AND EARLY THIS AFTERNOON ACROSS THE MID MISSISSIPPI VALLEY/SOUTHERN OHIO VALLEY DUE TO THE HIGHER INSTABILITY INTERACTING WITH NUMEROUS OUTFLOW BOUNDARIES FROM LAST EVENINGS CONVECTION OVER MISSOURI. THE RUC/GFS ACTUALLY MAINTAIN THE HIGHEST INSTABILITY SOUTH OF THE STATE. MEANWHILE...THE 40KM ETA SOLUTION SHOWS A MUCH HIGHER AXIS OF INSTABILITY DEVELOPING ALONG AND AHEAD OF THE SURFACE COLD FRONT THIS AFTERNOON. THINK THE ETA IS A LITTLE BIT AGRESSIVE IN BRINGING LOWER 60F DEWPOINTS INTO SE MICHIGAN BY 18Z. MODIFICATION OF ETA SOUNDINGS FOR A TEMP OF 71 OVER A DEWPOINT OF 56 HOWEVER STILL YIELDS 1000 J/KG CAPE. THINK THAT IF THIS CAPE IS REALIZED...THERE WILL BE A CHANCE FOR SEVERE WEATHER GIVEN 0-6KM SHEAR VALUES AROUND 40 M/S. SE MICHIGAN WILL ALSO BE WITHIN THE ENTRANCE REGION OF A 60KT MID LEVEL JET. A MID LEVEL DRY AIR INTRUSION...NOW SEEN OVER NORTHERN IOWA...IS ALSO EXPECTED TO MOVE ACROSS SE LOWER MICHIGAN THIS AFTERNOON. THIS WOULD ENHANCE THE NEGATIVE BOUYANCY POTENTIAL OF CONVECTIVE DOWNDRAFTS AND LOWER WET BULB ZERO HEIGHTS. DAMAGING WINDS AND LARGE HAIL WILL THUS BE OF CONCERN WITH ANY THUNDERSTORM THAT DEVELOPS. EVEN THOUGH THE ETA IS GENERATING CONVECTION FROM MID TO LATE AFTERNOON...HAVE SOME CONCERN THAT A PREFRONTAL TROUGH NOW NEAR THE CHICAGO AREA MAY INITIATE CONVECTION EARLIER...THUS WILL TIME THE RISK OF SEVERE WEATHER ANYTIME AFTER NOON. GIVEN THE RUC/GFS INDICATING MOST OF THE CONVECTION DEVELOPING SOUTH OF THE FORECAST AREA...A SOLUTION THAT DOES SEEM POSSIBLE...WILL LOWER POPS TO 50 PERCENT TODAY. DTX VAD WIND PROFILE SHOWS 60KT AT 2-3FT. THIS IS HIGH THAN INDICATED BY MODEL SOLUTIONS. EXPECT THE LOW LEVEL WINDS WILL SUBSIDE THIS MORNING...BEFORE DEEP MIXING GETS GOING. AT THIS POINT...WILL MENTION WIND GUSTS TO 35 MPH...BUT THIS WILL HAVE TO BE WATCHED...ESPECIALLY IF THERE IS MORE AFTERNOON SUNSHINE THAN EXPECTED. HIGH PRESSURE WILL BUILD INTO THE NORTHERN LAKES REGION TONIGHT IN THE WAKE OF THE SURFACE COLD FRONT. THE ETA SOLUTION BRINGS QUITE A BIT OF LOW LEVEL MOISTURE INTO THE AREA OVERNIGHT. THUS FAR..THE ETA HAS A GOOD HANDLE ON THE LOW CLOUDS OVER NORTHERN ONTARIO...SO WILL CARRY RATHER HIGH CLOUD COVER IN THE GRIDS IN EXPECTING SOME LOW MOISTURE TO BECOME TRAPPED UNDERNEATH THE SUBSIDENCE INVERION OVERNIGHT. WILL CONTINUE TO LEAN TOWARD THE MORE AMPLIFIED GFS SOLUTIN OF THE UPPER WAVE THAT WILL MOVE INTO THE WESTERN US ON THURSDAY. THE GFS HAS BEEN VERY CONSISTENT WITH THIS FEATURE AND REMAINS IN GOOD AGREEMENT WITH THE CANADIAN AND EUROPEAN MODELS. THE GFS HOWEVER STILL APPEARS TO BE SUFFERING FROM CONVECTIVE FEEDBACK OVER THE MIDWEST AND NORTHERN OHIO VALLEY THURSDAY INTO FRIDAY AND THUS DEVELOPS A SUSPICIOUS SURFACE LOW...TRACKING IT OVER LOWER MICHIGAN FRIDAY. IN THIS CASE PREFER THE ETA IDEA OF MAINTAINING HIGH PRESSURE/DRYER AIR OVER THE GREAT LAKES THROUGH FRIDAY. WILL THUS CARRY JUST A LOW POP NEAR THE OHIO BORDER THURSDAY NIGHT TO ACCOUNT FOR A WAVE THAT WILL TRAVEL ACROSS THE NORTHERN OHIO VALLEY...OTHERWISE WILL KEEP THE FORECAST DRY THROUGH FRIDAY. THE GFS SOLUTION HAS TRENDED SLOWER WITH THE DEEP UPPER TROUGH THAT WILL MOVE INTO THE CENTRAL US ON SATURDAY. IT APPEARS THERE WILL BE QUITE A BIT OF RIDGING ALOFT OVER THE GREAT LAKES ON SATURDAY. SO WILL PUSH BACK MENTION OF PRECIP UNTIL SATURDAY NIGHT AND SUNDAY. AS FOR TEMPERATURES THROUGH THE PERIOD...WILL NOT STRAY FAR FROM GUIDANCE TODAY WHICH AGREES WITH UPSTREAM CONDITIONS. LESS CLOUD COVER OR AN EARLIER START TO CONVECTION HOWEVER WILL HAVE BIG IMPACTS ON AFTERNOON TEMPS. HAVE CUT BACK HIGHS A BIT THURSDAY THROUGH FRIDAY THOUGH AS A PREDOMINATE EASTERLY FLOW WILL SET UP OVER SE MICHIGAN WITH WINDS OFF THE COLD WATERS OF LAKES HURON AND ERIE. && .DTX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ CONSIDINE EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 315 PM CDT WED APR 21 2004 .DISCUSSION... SECONDARY CD FRONT PUSHING INTO SE MN. STEEP LAPSE RATES AND A BIT OF CAPE OVER SW INTO CENTRAL MN...HAVE HELPED TO GENERATES A FEW SHWRS/TSTM. RUC SLIDES KEEP THE INSTABILITY AXIS OVER SOUTH CENTRAL MN..SO WILL ADD SOME T FOR EARLY EVENING AND A FEW SHWRS OVER WEST CENTRAL WI. GOOD PUSH OF DRIER AIR HELPING TO CLEAR OUT THE CLOUDS OVER NW MN AND WILL CONTINUE THIS TREND OVER MOST OF THE CWA TONIGHT. ETA CONTINUING TO KEEP MOST FORCING FROM DEVELOPING SPLIT TO THE SOUTH OF FROM THE CWA..BUT GFS IS ALSO SOMEWHAT CONSISTENT IN BRINGING SHORT WAVE FARTHER N. HOWEVER..CANADIAN AND UKMET KEEP PRECIP MAINLY SOUTH AS WELL. WILL KEEP THE SMALL POP IN THE SOUTH CENTRAL FOR THURSDAY EVENING. DON'T SEE A HUGE AMOUNT OF CLOUDS ON THUR..SO THINK GUID TEMPS A LITTLE ON THE COOL SIDE..WILL GO CLOSER TO ETA. MODELS COME INTO MORE AGREEMENT FOR UPPER LOW KICKING NE ON SAT...SO KEEPING CHANCE FOR SHOWERS AND EXPANDING INTO WISC. NO BIG CHANGES IN TEMPERATURE AND WILL DEPEND MORE ON CLOUD COVER. ALTHOUGH LOOKS FAIRLY DRY ON FRIDAY NIGHT WITH PRECIPITABLE WATER VALUES DROPPING. BROUGHT LOWS INTO THE UPPER 20S TO UPPER 30S. LONGER TERM...SATURDAY NIGHT THROUGH WEDNESDAY... GOING EXTENDED GRIDS LOOKED IN EXCELLENT SHAPE UPON ARRIVAL OF NEW ENSEMBLE AND OPNL RUNS. STILL BEST CHC OF PCPN COMES IN VRY BEGINNING OF EXTENDED (SAT NIGHT) AS EJECTING WRN US ENERGY SLIDES NORTHEAST...SPINNING UP LOW PRES THRU CNTL MS VLY. UPPED POPS A BIT ESP SRN CWA GIVEN NICE LIFT ON 295K. STILL SHOULD SEE BULK OF PCPN SLIDE SOUTH/EAST OF FCST AREA. WEAK FROPA SUN WITH SOME NRN STREAM ENERGY KEEPING THINGS SEASONABLE THRU TUE TEMP WISE...AND MORE SCT SHRA AROUND THE FRONT. DRY MON AND TUE PER MOST ALL OPNL AND ENSEMBLE RUNS. DRAMATIC WARMUP HINTED AT IN END OF EXTENDED PER HEIGHT ANOMALIES AND ENSEMBLE H85 TEMPS. WENT SIG ABV GUIDANCE NEXT WED. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ JPR/SEB mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC 935 AM EDT WED APR 21 2004 AREA OF MID CLOUDS WORKING INTO THE FAR SRN AND WESTERN PORTIONS OF THE CWA ATTM WILL LIFT ACROSS THE REGION BY EARLY AFTN. LATEST RUC GUIDANCE TRYING TO SHOW SOME QPF UNDER THIS CLOUDINESS ATTM BUT IT WOULD APPEAR GUIDANCE IS OVER DOING LOW LVL MSTR A BIT AS NO PCPN BEING REPORTED. THE CLOUDINESS MAY DELAY MAX HEATING SLIGHTLY BUT STILL FEEL HIGH TEMPS ON TRACK FOR TODAY...SIMILAR TO YESTERDAYS. WILL MAKE MINOR ADJUSTMENTS TO TEMP TRENDS...BUT WILL PLAN NO MAJOR UPDATE. .MARINE...MSAS/SFC ANALYSIS CURRENTLY DEPICTS WARM FRONT ALONG NC/VA BORDER LIFTING N...AND WELL ENTRENCHED SUMMER-LIKE HIGH PRESSURE DOMINATING OFFSHORE. RESULT WILL BE 10-20 KT SW FLOW PERSISTING OVER CWFA THRU REST OF WORK/SCHOOL (FOR SOME "BEACH") WEEK...AND SEAS REMAINING FLAG-FREE. BUOYS 41025/41013 PRESENTLY SHOWING 3-4 FT SEAS PUSHING IN FROM AFAR WITH RESIDUAL ESE SWELL ENERGY AT 9-10 SECOND INTERVALS. SURF CAMS/LOCAL REPORTS STATING AFORMENTIONED TRANSLATING INTO 1-3 FT WAVES ALONG OBX/CRYSTAL COAST SURF ZONES. RIP CURRENT FORECASTING WORKSHEET TODAY HAS CAPE LOOKOUT NATIONAL SEASHORE S TO NORTH TOPSAIL IN A MODERATE RISK OF RIPS TODAY FOR BEACH-GOERS. ALWAYS LOOKING TOWARD THE WEEKEND...GFS/ETA AGREE THAT BACKDOOR COLD FRONT APPROACHES REGION FROM N SATURDAY...BUT THAT'S WHERE IT STOPS. WHERE-AS GFS PUSHES FRONT S AND THRU...ETA DOES NOT. WITH STRONGER STAYING POWER OF CONSENSUS FLOW THINKING...GFS TO BE MODEL OF CHOICE AS BACK DOOR FRONT COULD GET AS FAR S AS NC/SC BORDER DURING BEFORE LIFTING N AS WARM FRONT AS NEXT COLD FRONT TO THE W TAKES AIM ON REGION MONDAY. ENDING UP ON A WARMER SEA SURFACE TEMPERATURE NOTE (AS COMPARED TO WINTERS UPPER 30S GRIP)...THIS MORNINGS 67 DEGREE SST READING AT BEAUFORT MARINE LAB IS HIGHEST SINCE 1ST WEEK IN NOV 2003 WHEN WATER TEMPS BEGAN THEIR DOWNWARD TREND OF OCEANOGRAPHIC THINKING. .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. && $$ MLF/GC nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 1126 AM EDT WED APR 21 2004 .DISCUSSION... CURRENT SFC ANALYSIS INDCG SFC LO ACRS CNTRL WISCONSIN WITH FRNTL BNDRY EXTENDING SSW ACRS ILLINOIS AND INTO CNTRL MISSOURI. PREFRNTL TROF OUT EXTENDING ACRS EASTERN ILLINOIS INTO WESTERN KY. CONVECTION HAD FIRED ALONG THE SOUTHERN PORTION OF THE TROF IN WESTERN KY/TN AS MID LVL VORT SHIFTING EAST. FCST AREA SHROUDED IN SC/AC THIS MRNG IN WARM SECTOR. BIG QUESTION FOR AFTN/EVNG REMAINS SVR POTENTIAL...AND SVRL FACTORS WILL ULTIMATELY DETERMINE WHETHER TSTMS GO SVR. MODEL SOUNDINGS INDCG POTENTIAL FOR SOME MID LVL DRYING THIS AFTN...BUT LO LVL MOISTURE REMAINS ABUNDANT. BIGGEST FACTOR IS AMOUNT OF SUNSHINE AND SFC HEATING THAT CAN DVLP AND HAVE SEEN SCOURING OF CLOUDS IN LAST HOUR...MOST NOTICEABLY ACRS EASTERN INDIANA AND WEST CNTRL OH. 12Z META AND CURRENT RUC DATA ALL INDCG THAT BEST ENVIRONMENT FOR STRONG/SVR STORMS WILL BE LOCATED ACRS INDIANA AND INTO WEST CNTRL OH AND THE DAYTON AREA. SBCAPES CLIMB TO 1000-1500 J/KG BY LATE AFTN WITH A SWATH OF 150-200 J/KG 0-3 KM CAPE BTWN 21Z AND 00Z...WITH THIS AXIS SHIFTING EAST ACRS FCST AREA LATER THIS EVNG. WBZEROS WILL BE BTWN 7 AND 9KFT AND IDEAL FOR HAILERS. HOWEVER...LO LVL CONVERGENCE STRONGEST RIGHT NOW...AND WILL CONTINUE TO WEAKEN INTO AFTN AS 850 35-40 KT LLJ PULLS OFF TO NORTHEAST. OTHER BIG FACTOR IS TSTM AREA APPCHG SW FCST AREA ATTM. THICKER CLOUDS AND PCPN AREA JUST ABOUT INTO NRN KY COUNTIES...AND WILL REACH CVG METRO SHORTLY AFTER 16Z. THIS COULD KEEP ATMOSPHERE MORE STABLE INTO AFTN AND SQUELCH TSTM POTENTIAL. HOWEVER...THE BULK OF THIS PCPN AREA WILL REMAIN SOUTH AND EAST OF WEST CNTRL OH/DAYTON AREA WHERE AFOREMENTIONED CAPE VALUES PROGGED TO POOL BY LATE AFTN. IN A NUTSHELL...ALL THESE FACTORS WILL CONTRIBUTE TO LKLY SHRA/TSTMS THIS AFTN. POTENTIAL FOR SVR REMAINS...ESPECIALLY FOR WEST CNTRL OH SOUTH INTO THE DAYTON AREA AND THE WHITEWATER VALLEYS. HOWEVER... FEEL SVR POTENTIAL WILL REMAIN ISOLD BASED ON ABOVE FACTORS. SVR POTENTIAL WILL DECREASE THIS EVNG WITH LOSS OF SFC HEATING. WILL TWEAK TEMPS A BIT ACRS FCST AREA...ESPECIALLY RAISING A FEW DEGREES IN WEST CNTRL OH AND OPENING RANGES IN SOUTH CNTRL OH WITH BIT MORE SUNSHINE. STILL OPTIMISTIC THAT CVG/CMH AREAS WILL BE ABLE TO GET INTO L70S WITH LIMITED SUN. REST OF FCST REMAINS UNCHANGED. UPDATE OUT SHORTLY. && .ILN WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...NONE. OH...NONE. && $$ RYAN oh AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 1002 PM EDT WED APR 21 2004 .UPDATE... REGIONAL RADAR SHOWS SHOWERS AND THUNDERSTORMS JUST TO OUR WEST. TRAJECTORY OF THIS CONVECTION INDICATES SOME COULD BRUSH OUR WRN MTN COUNTIES. 18Z ETA DOES INDICATE PRECIP JUST OVER OUR SIDE OF THE BORDER WHILE RUC AND 18Z GFS KEEP IT JUST WEST. THINK BEST PLAN WILL BE TO UPDATE TO ADD SLIGHT CHC OVERNIGHT FOR THE BORDER COUNTIES. WILL LEAVE REST OF MTNS DRY AS I EXPECT BULK OF PRECIP TO BE ON THE TENNESSEE SIDE. ELSEWHERE LITTLE CHANGE XCPT FOR CLOUD COVER. SAT PIX SHOW DRY SLOT HAS WORKED IN WITH MOSTLY CLEAR SKIES OUTSIDE OF THE MTNS AND THIS SHOULD CONTINUE MOST OF THE NIGHT. && .PREV DISCUSSION... SEVERAL MCS/S WL DEVELOP OVER THE SRN/CNTRL PLAINS AND MOVE ENE INTO THE LOWER OHIO VALLEY THROUGH THE REMAINDER OF THE WEEK. AS HAS BEEN THE CASE FOR THE PAST SEVERAL DAYS...HIGH PRESSURE OVER THE SE STATES WL KEEP MOST OF THE ACTIVITY TO OUR WEST UNTIL COLD FRONT MAY...OR MAY NOT...OOZE INTO THE CWA ON SAT. AN AREA OF EXCEPTIONALLY DRY LLVL AIR ON THE PERIPHERY OF THE RIDGE HAS WORKED ITS WAY INTO THE HIGHER TERRAIN THIS AFTN. YDAY THE DRY AIR WAS EVIDENT OVER LA...AND THIS MORNING IT SHOWED UP AS AN AREA OF +30 DEG DWPT DEPRESSIONS BEGINNING ABOUT 900 MB ON THE FFC SOUNDING. AS A RESULT...AVL DWPTS HAVE MIXED OUT INTO THE UPPER 20S...WTIH RH VALUES FALLING INTO THE TEENS. LOW DWPTS SHOULD RECOVER FAIRLY QUICKLY THIS EVENING AS THE AREA OF VERY LOW DWPTS IS RATHER SMALL. PERSISTENT LLVL MOISTURE DIVERGENCE AND SUBSIDENCE WL CONTINUE FOR THE NEXT COUPLE DAYS ACROSS THE CWA. WHILE A RATHER POTENT MCS SHOULD DEVELOP OVER OK THIS EVENING AND RACE ENE ALONG SFC FRONT...WITH A SIMILAR SYSTEM DEVELOPING LATE TMRW...ABOUT THE ONLY THING WE MIGHT SEE AS A RESULT WOULD BE YET MORE MID AND HIGH LEVEL CLOUDS. WINDS LOOK TO BE A LITTLE LIGHTER TMRW AFTN..BUT WL STILL GO WITH BREEZY WORDING IN THE ZONES. FRI IS A LITTLE MORE INTERESTING AS BOTH ETA AND GFS INCREASE THE DEEP LAYER SHEAR ACROSS THE CWA AND TURN THE FLOW MORE WLY. THEREFORE...WE MAY BE A LITTLE MORE AT RISK AT SEEING SOME KIND OF CONVECTION WORK ITS WAY INTO THE WRN ZONES LATE. HOWEVER...AS SFC FRONT WL LIFT NORTH THU TNGT...EXPECT CONVECTIVE INITIATION TO BE FAR ENUF N FRI...THAT RESULTANT MCS WL MOST LIKELY AFFECT THE VIRGINIAS. BY SAT THE GFS AND ETA BRING THE FRONT INTO THE REGION. THE ETA BRINGS THE FRONT FARTHER S THAN DOES THE GFS. PATTERN WL BE SHARPENING UP AT LITTLE BY SAT...WITH SHORT WAVE RIDGING DEVELOPING ACROSS THE CWA...AND MID LEVEL CONFLUENCE STRENGHTENING OFF THE MID ATLANTIC. THIS WL FAVOR SOME WEAK CAD...THOUGH I LIKE THE GFS/S SOLUTION WITH THE FRONT ONLY MAKING IT INTO THE NC ZONES. SINCE WE WL FINALLY HAVE LLVL MOISTURE CONVERGENCE...WL HOLD ON TO CHANCE POPS NRN PART OF CWA VCNTY FRONT. LACK OF SHEAR MEANS MOST LIKELY THAT CONVECTION WL BE RATHER WEAK. BEGINNING OF EXTENDED FORECAST HAS AREA IN WARM SECTOR AHEAD OF COLD FRONT IN MS VALLEY. CARRYING SMALL POPS AHEAD OF FRONT AS MOISTURE GRADUALLY INCREASES. BETTER POPS SUN NIGHT AND MON AS FRONT CROSSES AREA. GFS SUGGESTS AREA UNSTABLE ENOUGH FRO THUNDER ROUND THE CLOCK IN ADVANCE OF FRONT. DRYING LATE TUE AS SURFACE RIDGE AND NW FLOW MOVE OVER AREA. COLD ADVECTION AT LEAST PARTIALLY OFFSET BY DOWNSLOPE FLOW. SURFACE RIDGE OVER AREA WED...BUT THICKNESS STILL SUPPORTS TEMPERATURES ONLY COOLING TO NEAR NORMAL VALUES. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ RWH sc SOUTH TEXAS FORECAST DISCUSSION NATIONAL WEATHER SERVICE CORPUS CHRISTI TX 930 PM CDT WED APR 21 2004 .UPDATE...SKIES HAVE TEMPORARILY CLEARED ACROSS THE MAJORITY OF THE CWA...EXCEPT NRN VICTORIA AND GLIAD COUNTIES. EXPECT LOW STRATUS TO ONCE AGAIN DEVELOP AFTER MIDNIGHT ACROSS ERN 2/3RDS OF CWA...SIMILAR TO RUC. CIRRUS ACROSS NRN MEXICO MAY ALSO CLIP SW AREAS IN WEBB. WINDS WILL ALSO CONTINUE TO SLOWLY DECOUPLE LAND AND BAYS AND WILL MAKE SOME MINOR TWEAKS IN ZFP/GRIDS REFLECTING CURRENT TRENDS AND EXPECTATIONS. TEMPS APPEAR ON TRACK. .MARINE...WILL LIKELY DROP SCA OVER THE BAYS IN CWF UPDATE... REPLACING WITH SCEC. WINDS OVER THE NEARSHORE WATERS HAVE FALLEN INTO SCEC RANGE...BUT MAY LIKELY SEE A JUMP BACK UP AROUND 20 KNOTS MID-3 A.M. AS NOCTURNAL JET SETS UP SIMILAR TO LAST NIGHT. THEREFORE WILL KEEP SCA GOING FOR NEARSHORE. SCA WILL CONTINUE FOR OFFSHORE WATERS WITH SEAS 6 TO 8 FEET (WINDS 15 TO 20 KNOTS). .AVIATION...VFR CONDITIONS THROUGH 06Z. MVFR CIGS LIKELY AFTER 06Z ERN 2/3RDS OF S TX AS LOW STRATUS DEVELOPS...WITH SOME LOCATIONS TEMPORARILY DROPPING JUST INTO IFR RANGE TOWARDS SUNRISE. SOME LIGHT FOG REDUCING VSBLTYS 4-6 MILES ALSO POSSIBLE ACROSS INLAND AREAS OF COASTAL BEND CLOSER TO SUNRISE. WINDS WILL CONT TO WEAKEN OVERNIGHT. && .CRP WATCHES/WARNINGS/ADVISORIES...SCA 250-255-270-275. && $$ 76...SHORT-TERM tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE SAN ANGELO TX 848 PM CDT WED APR 21 2004 .UPDATE... STORMS CONTINUE ACROSS ALL BUT THE SOUTHWEST SECTIONS OF OKLAHOMA... AS DRYLINE SURGED EASTWARD ACROSS THE AREA. CURRENT DEWPOINTS IN THE 30S ACROSS THE NORTHWEST HALF OF THE AREA...BUT DRYLINE STARTING TO RETREAT QUICKLY THIS EVENING AND BROWNWOODS DEWPOINT HAS CLIMBED BACK INTO THE 60S. THIS RETREAT IS WELL AHEAD OF ALL OF THE MODELS EARLIER FORECASTS. WILL WAIT AND SEE WHAT THE 00Z RUC ENDS UP SHOWING...BUT EXPECT TO MAKE SOME SMALL ADJUSTMENTS WITH REGARDS TO OVERNIGHT LOWS...DEWPOINTS...AND POSSIBILITY OF LOW CLOUDS CREEPING BACK INTO AT LEAST THE SOUTHEAST SECTIONS OF THE AREA. UPDATED GRIDS AND TEXT PRODUCTS OUT SHORTLY. && .PREV DISCUSSION... SURFACE DRYLINE WILL CONTINUE ITS SLOSH CYCLE BACK AND FORTH ACROSS WEST CENTRAL TEXAS THROUGH FRIDAY. THE DRYLINE HAS PUSHED EAST ACROSS OUR COUNTIES THIS AFTERNOON AND IS CURRENTLY CLOSE TO A JUNCTION TO THROCKMORTON LINE. EXPECT THIS DRYLINE TO MOVE JUST EAST OF OUR CWFA BEFORE IT RETURNS LATER TONIGHT. AS THE DRYLINE MOVES BACK WEST ACROSS OUR COUNTIES TONIGHT...EXPECT STRATUS ONCE AGAIN BY SUNRISE. WITH SURFACE DEWPOINTS REBOUNDING QUICKLY ACROSS WEST CENTRAL TEXAS TONIGHT...WILL GO WITH OVERNIGHT LOWS A COUPLE DEGREES ABOVE MAV MOS AND CLOSER TO PERSISTENCE. EXPECT CLOUD COVER TO MODERATE AFTERNOON HIGHS TOMORROW. HOWEVER...EXPECT NUMBERS AROUND 90 ACROSS THE BOARD. ON FRIDAY...THE DRYLINE WILL STALL ACROSS OUR CENTRAL COUNTIES AS A SURFACE COLD FRONT MOVES ACROSS THE TEXAS PANHANDLE. WILL CONTINUE LOW POPS FOR FRIDAY WITH THE DRYLINE PROVIDING THE LOW- LEVEL FORCING. HOWEVER...APPEARS BEST UPPER-LEVEL SUPPORT WILL BE NORTH OF OUR CWFA. FRIDAY NIGHT RAIN CHANCES LOOK BETTER AS THE COLD FRONT PUSHES SOUTH ACROSS WEST CENTRAL TEXAS. RAIN POTENTIAL CONTINUES SATURDAY...ESPECIALLY ACROSS OUR SOUTHEASTERN ZONES... WITH WEAK ISENTROPIC LIFT POSSIBLE. BEGINNING SUNDAY...A SURFACE HIGH PRESSURE RIDGE MOVES EAST ACROSS OKLAHOMA. RAIN CHANCES NOT VERY GOOD THROUGH MID WEEK. && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 07 tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE FORT WORTH TX 1140 AM CDT WED APR 21 2004 .UPDATE... 1140 AM CDT SFC LOW CONTINUES TO INTENSIFY IN THE PANHANDLE...WITH TRAILING DRYLINE EAST OF LBB AND MAF. ABUNDANT SUNSHINE TO EAST OF THE BOUNDARY WILL AID IN MIXING THE DRYLINE EASTWARD...SHOULD APPROACH WESTERN CWA BY MID-AFTERNOON. SFC BOUNDARY STRETCHING EAST FROM SFC LOW THRU CDS...LTS...TO NORTH OF OKC. WITH SIGNIFICANT SHEAR IN VICINITY OF THE BOUNDARY...LIKELY THE INITIAL FOCUS FOR TSRA DEVELOPMENT THIS AFTERNOON. 12Z FWD SOUNDING SHOWS LITTLE CAP COMPARED TO PREVIOUS DAYS. MESOETA SHOWING BL CAPES 1500-2000J/KG THIS AFTERNOON EAST OF DRYLINE. LOCAL ETA AND RUC IN LINE WITH SFC-BASED CAPES. MESOETA PUSHES DRYLINE TO BOWIE-MWL-LAMPASAS LINE BY LATE AFTERNOON. LOCAL ETA BULGES DRYLINE INTO FTW. DRYLINE MAY HAVE TO WAIT UNTIL LATE AFTERNOON TO TRIGGER STORMS...ONCE BOUNDARY REACHES AREA OF DIMINISHED CAP...SIGNIFICANT BL MOISTURE...AND SFC AIR REACHING CONVECTIVE TEMP. WILL HAVE 18Z SOUNDING TO FURTHER ASSESS SITUATION. CURRENT GRIDS ON TRACK. WILL FRESHEN THEM UP FOR CURRENT TRENDS. POP/WX FORECAST WILL REMAIN INTACT...WITH SVR MENTION LIMITED TO AREA EAST OF DTO-GLE AND NORTH OF DTO-SULPHUR SPRINGS. UPDATE OUT SHORTLY. 25 && .AVIATION... 600 AM CDT ONLY MINOR TWEAKS TO GOING TAF FCSTS. SC/MVFR DECKS PRETTY MUCH ENCOMPASSING MOST OF N TX...NAMELY ALONG/E OF I-35 CORRIDOR WITH SSW WINDS CONT IN 8-15 KT RANGE THROUGH 14Z. PER SWLY 35-45 KT FLOW ON VWP IN 1.5-2.5 KFT LYR...WILL INTRODUCE LLWS UNTIL 14Z OR SO THIS MORNING. DEEP MIXING/DEEPENING SFC LO OVR W TX GETS SLY FLOW CRANKING ABOUT 15-25 KTS WITH GUSTS UPWARDS TO 30 KTS AND VFR CONDS BY 18Z. AS PUBLIC DISC BELOW ALLUDES TO...SOME ISOLD TSRA COULD OCCUR AS FAR SOUTH AS N/NE PTNS OF METROPLEX...THOUGH ELEVATED MIXED LAYER(CAP) COULD HAVE CONTINUED IMPACT OF KEEPING ANY STORMS FROM INITIATING THIS FAR SOUTH...AND KEEP THEM MORE ALONG RED RIVER CLOSER TO BETTER MID/UPPER LVL FORCING COMING OVER OK AND SFC BOUNDARY WELL N OF THE RED RIVER. WE'LL BE DOING AN 18Z SOUNDING TO ANALYZE THIS FEATURE FURTHER. THUS...WILL NOT INTRODUCE ANY CB/VCTS FOR NOW WITH CONFIDENCE LOW AT D/FW SITES. OTRW...WILL BRING IN SC ON LLJ AGAIN BY 06Z/AFTER TNGT. 05/ && .UPDATE... 530 AM CDT AFTER FURTHER ANALYSIS AND INPUT FROM SURROUNDING OFFICES DOWN SOUTH (THANKS)...WILL TONE DOWN TO ONLY SLIGHT CHANCE POPS THURS/THURS NIGHT WITH LITTLE FOCUS OUTSIDE OF WAA. BEST CHANCE DOWN THAT WAY SHOULD COME BY FRI AFTERNOON INTO SAT...WHEN COLD FRONT/DRYLINE AND UPPER LVL DISTURBANCE APPROACHES AREA FROM THE WNW. UPDATES OUT SOON. && .PREV DISCUSSION... 200 AM CDT SHORTWAVE IN TX PANHANDLE THIS MORNING FORECAST TO MOVE INTO CENTRAL OKLAHOMA THIS EVENING. CAP WILL BE IN PLACE OVER NORTH TEXAS THIS AFTERNOON BUT WILL BE WEAKER NORTHEAST OF AN EMORY TO GAINESVILLE LINE. THIS AREA COULD GET SOME SEVERE STORMS LATE THIS AFTERNOON AND EVENING. REST OF NORTH TEXAS MAY GET SOME SHOWERS AND THUNDERSTORMS...BUT WITH CAP STILL IN PLACE NO WIDESPREAD ACTIVITY WILL OCCUR. OUTSIDE OF NORTHEAST PARTS OF NORTH TEXAS...ANY STORMS THAT FORM WILL DISSIPATE RAPIDLY AFTER SUNSET WITH LOSS OF AFTERNOON HEATING. BEST CHANCE OF WIDESPREAD THUNDERSTORMS STILL LOOKS TO BE THURSDAY NIGHT AND FRIDAY AS UPPER LOW IN THE NORTHWEST DROPS INTO COLORADO. HEIGHTS WILL LOWER AND CAP SHOULD BE MUCH WEAKER. LOW LEVEL MOISTURE SHOULD INCREASE THURSDAY AND THURSDAY NIGHT...AS THE GULF OF MEXICO IS BEGINNING TO RECOVER FROM THE STRONG COLD FRONT OF LAST WEEK. AS SURFACE LOW IN NORTHWEST TEXAS REDEVELOPS FURTHER WEST IN EASTERN NEW MEXICO IN RESPONSE TO APPROACH OF UPPER LOW...LOW LEVEL WINDS WILL INCREASE THURSDAY WITH MUCH OF THE AREA HAVING GUSTY SOUTH WINDS 20-30 MPH. DEWPOINTS IN NORTH TEXAS SHOULD BE AT LEAST INTO THE MID 60S BY LATE THURSDAY WITH UPPER 60S DEWPOINTS INTO SOUTHEAST PARTS OF THE REGION. AFTER THIS SYSTEM MOVES THROUGH NORTH TEXAS FRIDAY AND SATURDAY...RAIN CHANCES WILL BE NIL SUNDAY THROUGH AT LEAST MID WEEK. 59 && .PRELIMINARY POINT TEMP/POPS... DALLAS-FT. WORTH, TX 80 65 78 65 / 20 30 30 40 WACO, TX 82 68 81 69 / 0 20 20 30 PARIS, TX 79 64 76 64 / 30 30 40 40 DENTON, TX 79 65 78 65 / 20 30 30 40 MCKINNEY, TX 79 65 78 65 / 20 30 30 40 DALLAS, TX 80 66 78 66 / 20 30 30 40 TERRELL, TX 80 65 79 68 / 30 30 30 40 CORSICANA, TX 81 67 80 70 / 20 30 20 40 TEMPLE, TX 83 68 82 70 / 0 20 20 30 && .FWD WATCHES/WARNINGS/ADVISORIES... TX...NONE. && $$ tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREEN BAY WI ISSUED BY NATIONAL WEATHER SERVICE MARQUETTE MI 315 PM CDT WED APR 21 2004 .DISCUSSION... CURRENT WEATHER...18Z WATER VAPOR LOOP AND 500MB RUC ANALYSIS SHOWED RIDGING ALONG THE EAST COAST...A SHRTWV TROUGH MOVING ACROSS THE GREAT LAKES AND WESTERN ONTARIO...AND A SHRTWV OVER WESTERN OREGON MOVING SE. SHRTWV TROUGH OVER THE GREAT LAKES AIDED IN RAIN SHOWERS OVER WI AND MI...WHICH HAVE NOW STRENGTHED INTO THUNDERSTORMS OVER LOWER MI DUE TO THE INFLUENCE OF DAYTIME HEATING. AT THE SFC...LOW PRESSURE WAS LOCATED OVER EASTERN ONTARIO WITH TWO COLD FRONT ASSOCIATED WITH IT...ONE EXTENDED SW TO THE MILWAUKEE AREA AND THE SECOND ALONG THE MN/ONTARIO BORDER. FURTHER OFF TO THE WEST...HIGH PRESSURE WAS BUILDING SOUTH FROM MANTIOBA...ALLOWING SKIES TO GENERALLY BE PARTLY CLOUDY FROM WESTERN IOWA/MN UP INTO MANITOBA PER VISIBLE SATELLITE LOOP. HOWEVER...CLOUD COVER AND -SHRA OVER WI ASSOCIATED WITH THE SHRTWV HAVE HELD TEMPS IN THE MID 40S TO MID 50S...WITH THE WARMEST READINGS OVER THE SOUTHERN PART OF THE STATE WHERE SOME SUNSHINE HAS BROKEN THROUGH. TONIGHT...WITH THE SHRTWV TROUGH EXITING PER 12Z ETA/GFS...LOOKS LIKE A QUIET NIGHT ON TAP. ANY -SHRA SHOULD END IN THE EVENING...THEN AS THE HIGH IN MANTIOBA MOVES DOWN (DRAGGING THE DRY AIR WITH IT)...SKIES WILL TURN PARTLY CLOUDY. MIN TEMPS A LITTLE TRICKY WITH COLD AND DRY AIR ADVECTION...AND PARTIALLY CLEARING SKIES. WILL GO WITH FWC GUIDANCE FOR LOWS...BUT IF SKIES CLEAR OUT MORE...TEMPERATURES MAY FALL A FEW DEGREES LOWER ACROSS THE NORTH. THURSDAY...HIGH PRESSURE DOMINATES THE DAY WITH IT SETTING UP OVER UPPER MICHIGAN. THAT LOCATION WILL KEEP EASTERLY FLOW ACROSS THE CWA...KEEPING LAKESHORE AREAS IN THE 40S. MOSTLY SUNNY SKIES AND 850MB TEMPS AROUND -2C WILL ALLOW TEMPERATURES TO CLIMB UP TO AROUND 50 INLAND. THURSDAY NIGHT...GFS AN OUTLIER HERE SHOWING A SFC LOW MOVING UP FROM OKLAHOMA TONIGHT UP INTO NORTHERN ILLINOIS. APPEARS THAT THE PROBLEM RESULTED FROM CONVECTIVE FEEDBACK TONIGHT. ETA/UKMET A LITTLE MORE REALISTIC SHOWING THE SURFACE LOW HEADING UP THROUGH THE OHIO VALLEY WHILE HIGH PRESSURE REMAINS IN CONTROL. STILL...IT APPEARS THAT SOME HIGH CLOUDS MAY MOVE IN DURING THE EVENING ASSOCIATED WITH THE SYSTEM. AS THE SYSTEM PULLS AWAY...THE HIGH CLOUDS WILL DISSIPATE AND LEAVE MOSTLY CLEAR SKIES ACROSS THE CWA. WITH ALREADY LOW DEWPOINTS ASSOCIATED WITH THE HIGH (FROM LOW 20S NORTH TO LOW 30S SOUTHEAST)...AND LIGHT WINDS...TEMPS SHOULD FALL TO THE DEWPOINTS. FRIDAY...SHRTWV TROUGH...CURRENTLY IN NORTHERN ALBERTA...MOVES ACROSS THE NORTHERN GREAT LAKES PER ETA/GFS. HOWEVER...WITH MOISTURE LACKING DUE TO A COLD FRONT OVER THE OHIO VALLEY AND INFLUENCE OF DRY AIR FROM THE HIGH ON THURSDAY NIGHT MOVING OFF TO THE EAST...EXPECTING ONLY SOME CLOUDS OUT OF THE TROUGH. WITH SOME SUNSHINE AND 850MB TEMPS AROUND 0C...HIGHS WILL BE IN THE MID 50S. FRIDAY NIGHT AND SATURDAY...HIGH PRESSURE BUILDS IN BEHIND THE TROUGH USHERING IN MORE DRY AIR AND CLEARING THE SKIES OUT. SOME COLD ADVECTION ALSO OCCURS BEHIND THE SHRTWV...HOWEVER IT IS SHORT LIVED. ETA/GFS SHOWS THE 850MB TEMPS FALLING TO -8C AT 06Z SAT...BUT BY 18Z THESE WILL HAVE RISEN TO -2C AT 18Z SAT. SO ALTHOUGH TEMPS MAY BE QUITE COOL FRI NIGHT...IN THE UPPER 20S TO MID 30S...TEMPS SHOULD RISE BACK UP INTO THE 50S ON SAT. EXTENDED (SUN THROUGH WED)...ALL EXTENDED MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE PATTERN THROUGH THE EXTENDED...SHOWING A TROUGH MOVING THE GREAT LAKES ON SUN (ASSOCIATED WITH A MERGER OF THE NORTHERN STREAM AND THE SHRTWV IN OREGON) WHILE RIDGING BUILDS IN THE WEST. THEN AS A SERIES OF SHRTWVS MOVE ACROSS THE PACIFIC...THE RIDGE BUILDS EASTWARD. MAIN UNCERTAINITY IS HOW FAST THE RIDGE BUILDS EAST...WHICH WILL DEPEND ON HOW DEEP THE TROUGH IS OVER THE GREAT LAKES. ECMWF RUNS HAVE BEEN NOT AS DEEP...THEREFORE THE MORE SIGNIFICANT WARMING COMES IN ON TUESDAY. GFS/UKMET RUNS ARE SLOWER DUE TO A DEEPER TROUGH. GFS ENSEMBLES ARE EVEN A TAD SLOWER THAN THE OPERATIONAL RUNS. CANADIAN ENSEMBLES SIMILAR TO GFS. THEREFORE WILL FOLLOW THE SLOWER SOLUTION. AS FOR THE WEATHER...COLD AIR ALOFT ALONG WITH PVA WILL YIELD TO SOME -SHRA ON SUNDAY. HIGH PRESSURE BUILDS IN FOR THE NEXT 3 DAYS BRINGING INCREASING SUNSHINE...THOUGH MONDAY MAY STILL BE A BIT CLOUDY WITH COLD AIR HANGING ON. BELOW NORMAL TEMPERATURES FOR SUNDAY AND MONDAY WITH THE INFLUENCE OF THE TROUGH...BUT THEN WITH AIR MASS MODIFICATION AND THE WESTERN RIDGE PROGRESSING EASTWARD...TEMPERATURES WILL RISE ABOVE NORMAL BY WEDNESDAY. && .GRB WATCHES/WARNINGS/ADVISORIES...NONE. && $$ AJ WWW.CRH.NOAA.GOV/GRB wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 300 PM CDT WED APR 21 2004 .DISCUSSION...FORECAST FOCUS ON RESOLVING MODEL DIFFERENCES FOR THURSDAY AFTERNOON THROUGH FRIDAY. IN THE SHORT TERM...ETA/GFS/NGM/RUC PROGS IN VERY GOOD AGREEMENT WITH RAPID DECREASE IN WINDS AS WEAK SURFACE HIGH SETTLES OVER REGION. EXPECT BREAKS IN CLOUDS AND LIGHT WINDS AFTER SUNSET SO HAVE DROPPED LOW TEMPERATURE FORECAST FOR OVERNIGHT. IN THE FAR TERM...GFS ODD PROG OUT FROM THE TIME PERIOD THURSDAY AFTERNOON THROUGH FRIDAY WITH OTHER PROGS INCLUDING CANADIAN AND UK MET MODELS. GFS SOLUTION FEATURES A MORE NORTHERN EXTENSION OF INVERTED TROUGH FROM DEVELOPING LOW PRESSURE OVER MIDDLE MISSISSIPPI VALLEY. ASSOCIATED MIDDLE AND UPPER STRUCTURE OF SHORT WAVE AND VERTICAL MOTION ENSURES WALL OF WATER FOR ALL OF CWA BEGINNING THURSDAY AFTERNOON AND ENDING FRIDAY. ALL OTHER PROGS KEEP CWA DRY DUE TO DECENT DRY LOW LEVEL EAST-NORTHEAST WIND FLOW AND ONLY TOKEN UPPER LEVEL DIVERGENCE...WHILE TAKING BULK OF STORM SUPPORTING ENERGY TO THE SOUTH OF THE CWA. FOR NOW HAVE OPTED TO KEEP CURRENT FORECAST DRY FOR THURSDAY AND FRIDAY AND LET LATER MODEL RUNS RESOLVE DIFFERENCES. && .MKX...NONE. $$ ZAJDEL wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 430 AM CDT THU APR 22 2004 .DISCUSSION... FORECAST CONCERNS CONTINUE TO BE PRECIP TRENDS AND COVERAGE INTO THE WEEKEND. MODEL DISPARITIES MAKE THIS A TRICKY FORECAST...BUT THERE IS A LITTLE BETTER AGREEMENT FOR TODAY/TONIGHT AND THE SYSTEM ON SATURDAY. IN THE NEAR TERM...LIGHT RAIN CONTINUES TO FESTER NEAR THE IA/NE BORDER AND KEPT SLT CHC POPS IN THE FAR WEST THROUGH THE DAY. THE 06Z ETA HAS LATCHED ONTO THE SCENARIO THAT THE EXTENDED RUC HAS BEEN PRESENTING SINCE YESTERDAY...IN SURGING THETA-E ADVECTION NORTHWARD INTO SOUTHERN IOWA LATE THIS AFTERNOON AND TONIGHT. ETA HAS HAD A FAVORABLE TRACK RECORD WITH RECENT CONVECTION AND WL LEAN HEAVILY TOWARDS IT'S SOLUTION FOR LATE AFTERNOON INTO FRIDAY MORNING. THE GFS HAS SHOWN LITTLE CONSISTENCY AND CONTINUES TO DEVELOP A HUGE QPF BULLSEYE...BUT TODAY MOVES IT THROUGH MO AND NRN IL INSTEAD OF RIGHT THROUGH IOWA WITH PREVIOUS RUNS. BELIEVE SOME CONVECTION WILL SPREAD INTO FAR SOUTHERN IOWA AFTER 4 PM AND KEPT SLT CHC FARTHER NORTH ALONG A SECONDARY WEAK MOISTURE CONVERGENCE AREA. WEAK INSTABILITY AND MID LEVEL LAPSE RATES SHOULD PRECLUDE ANY SEVERE STORMS. CONDITIONS THAT PRODUCED AN ISOLATED STORM WITH PENNY HAIL IN AUDUBON COUNTY LAST EVENING INCLUDED ABOUT 500 J/KG OF CAPE...STRONG SHEAR...AND STEEP MID LEVEL LAPSE RATES...PARAMETERS THAT DON'T LOOK TO BE COMING TOGETHER LATE AFTERNOON AND TONIGHT. HOWEVER...COVERAGE OF STORMS OVER THE SOUTH HALF SHOULD BE DECENT TONIGHT AND MAINTAINED LIKELY POPS. THERE IS BETTER MODEL AGREEMENT SAT/SAT NITE AS THE MAIN UPPER LOW SWINGS THROUGH AND MOST LOCATIONS COULD SEE SOME SUBSTANTIAL RAINFALL...ON THE ORDER OF AN INCH OR MORE. SOME SHOWERS COULD LINGER INTO SUNDAY...MAINLY NORTH AS MEAN H5 TROF AXIS MOVES THROUGH. LITTLE CHANGE TO GOING TEMPERATURES...WITH WARMING TREND STILL ON TARGET FOR NEXT WEEK. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ KINNEY ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 329 AM EDT THU APR 22 2004 .DISCUSSION... WV IMAGERY AND SFC OBS SHOWS SHRTWV AND ASSOC SFC TROF MOVG THROUGH THE WRN FORECAST AREA ATTM. IMPRESSIVE DRYING AND SUBSIDENCE IN WAKE OF SHORT WAVE. UPSTREAM DWPNTS LOWERING INTO LOWER 20S JUST NORTH OF LAKE SUPERIOR AS CLOUDS HAVE BROKEN UP ACROSS MUCH OF OUR WESTERN COUNTIES. EXPECT THIS CLEARING TO PROGRESS QUICKLY EASTWARD MORE IN LINE WITH RUC FCST SNDGS. ETA SNDGS TOO PESSIMISTIC HOLDING ON TO LOW LEVEL MOISTURE. TODAY...MODELS SHOW COOL CANADIAN HIGH PRES CENTER SETTLING IN OVER NRN LAKE SUPERIOR THIS AFTERNOON. MIDDAY 850 MB TEMPS OF -2C SOUTH TO -4C NORTH SHOULD KEEP TEMPS IN LOW 40S NORTH ALONG THE LAKE SUPERIOR SHORE TO AROUND 50 ALONG THE WI BORDER UNDER FULL SUN. TONIGHT...DEWPTS IN THE TEENS UNDER THE HIGH OVER WRN ONTARIO. AS SFC RIDGE SETTLES OVERHEAD TONIGHT...CLEAR SKIES AND NEAR CALM WIND WILL ALLOW TEMPS TO PLUMMET UNDER PRIME RADIATIONAL COOLING CONDS. TEENS SHOULD BE EASILY REACHED OVER THE USUAL INTERIOR COLD SPOTS WITH A RECORD LOW POSSIBLE AT THE MARQUETTE FCST OFFICE (PREV LOW TEMP 21F). FRIDAY...MODELS TRENDING QUICKER WITH PASSAGE OF CDFNT IN ASSOC WITH NRN BRANCH SHORTWAVE NOW MOVG INTO ALBERTA. BELIEVE MODEL SNDGS MAY BE OVERDOING CLOUD COVER IN ASSOC WITH FRONT AS HIGH PRES AND ASSOC DRY AIR AHEAD OF FRONT WILL LIMIT MOISTURE RETURN. HAVE KEPT FORECAST DRY WITH PARTLY CLOUDY SKIES. 850 MB TEMPS OF -1 TO -2C AHEAD OF CDFNT SHOULD STILL YIELD HIGHS IN THE UPPER 40S TO LOW 50S (CLOSE TO MODEL GUIDANCE AND GOING FCST) UNDER SCT-BKN CLOUD COVER. LOWERED TEMPS FRI NIGHT AS INFLUX OF DRY AIR (DEWPOINTS IN THE UPPER TEENS TO LOW 20S) AND RDG BUILDING OVERHEAD ESPECIALLY OVER WESTERN COUNTIES WILL AGAIN ALLOW READINGS TO DIP INTO THE LOWER 20S ACROSS MUCH OF CWA'S INTERIOR. SATURDAY...WITH 8H RDG BUILDING OVER THE AREA AND DAYTIME 8H TEMPS REBOUNDING TO 0 TO -2C PER 00Z MODELS...CURRENT FCST HIGHS IN MID TO UPPER 40S NORTH AND MID 50S SOUTH STILL LOOK REASONABLE UNDER EXPECTED FULL SUN. EXTENDED...00Z GFS AND CANADIAN MODELS SEEM TO TRENDING SLOWER THAN 12Z RUNS WITH SYSTEM EMERGING OUT OF THE SRN PLAINS. THEY ALSO SHOW STRONG SFC RDG OVER THE AREA PUSHING SRN SYSTEM AND ASSOC PCPN WELL SOUTHEAST OF FORECAST AREA. MEANWHILE...00Z ETA AND UKMET LOOK TO BE MORE AGGRESSIVE PUSHING SRN STREAM WAVE AND PCPN DUE NORTH INTO WRN GRT LAKES AND UPR MIDWEST. THIS SOLN SEEMS A BIT SUSPICIOUS GIVEN STRENGTH OF RDG THAT WILL BE OVER THE AREA. THUS...HAVE DECIDED TO KEEP SAT NIGHT DRY AND BRING A CHC OF -RA INTO AREA FOR SUN. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VOSS mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPRINGFIELD MO 359 AM CDT THU APR 22 2004 .DISCUSSION... ACTIVE PATTERN CONTINUES WITH LARGE AREA OF STRATIFORM RAIN MOVING THROUGH SOUTHERN HALF OF CWA THIS MORNING. THIS PRECIP IS FAR NORTH OF ACTIVE SURFACE/NEAR SURFACE BASED CONVECTION OVER CENTRAL OK INTO CENTRAL ARKANSAS, AND HAS LIKELY BEEN DRIVEN BY DIVERGENCE CENTERED NEAR 250 MB COUPLED WITH MID LEVEL (500 MB TO 700 MB) CONVERGENCE AS SHOWN IN RUC AND ETA OUTPUT. MCV WHICH FORMED ALONG KANSAS/OK LINE IS RAPIDLY SHEARING OUT IN DIFFLUENT FLOW, AND WILL ONLY PROLONG STRATIFORM PRECIP THROUGH EARLY MORNING. BACK EDGE OF PRECIP SHOULD CLEAR CWA BY AROUND 18Z. MAY SEE A SIGNIFICANT BREAK IN THE PRECIP TODAY, AS SURFACE BOUNDARY WILL REMAIN OVER CENTRAL ARKANSAS. ETA SURFACE PROGS LOOK WAY TOO FAR NORTH WITH THIS BOUNDARY THIS AFTERNOON, AND THINK THE MID 60 DEWPOINTS SHOWN IN THE ETA REACHING SRN MO ARE A FANTASY. ETA AFTERNOON CONVECTIVE CLUSTER JUST NORTH OF BOGUS SURFACE BOUNDARY NEAR SGF IS DISCOUNTED. THINK THAT SURFACE TEMP/DP OF AROUND 70/58 WILL GIVE STRATOCU CAPPED BY 700 MB INVERSION THIS AFTERNOON AND THATS ABOUT ALL. TONIGHT IS A DIFFERENT STORY AS ONCE AGAIN EMPHASIS SHIFTS TO WHATS GOING ON ABOVE THE SURFACE. VERY STRONG 850 MASS CONVERGENCE SHOULD LEAD TO A CONVECTIVE CLUSTER NEAR THE ARKANSAS STATE LINE, OR PERHAPS A BIT FARTHER NORTH. WILL GO WITH HIGH POPS SOUTH TO LOW CHANCE NORTH. HEAVY RAIN AGAIN A THREAT NEAR THE STATE LINE. BOTH GFS AND ETA HAVE SLOWED THE EJECTION OF THE MAIN LOW/TROUGH TO 12Z SUNDAY. SINCE BOTH MODELS ARE IN VERY GOOD AGREEMENT ON THIS, WILL GO AHEAD AND KEEP CONVECTION IN FORECAST THROUGH SATURDAY NIGHT. FLOODING THREAT IS STILL THERE DEPENDING ON HOW MUCH RAIN WE GET TONIGHT, SO WILL REISSUE ESF AND DELAY ANY FLOOD WATCH SINCE IT IS SUCH A LONG DURATION EVENT. DAY SHIFT CAN ANALYZE WHAT HAS ALREADY FALLEN, NEW FLASH FLOOD GUIDANCE, AND ANOTHER SUITE OF MODEL OUTPUT BEFORE MAKING A DECISION. ROCKIES MID LEVEL RIDGE AND EAST COAST TROUGH YIELD LATER PERIODS WHICH ARE DRY WITH NORMAL TO BELOW NORMAL TEMPS IN DEEP NORTHWEST FLOW PATTERN. BROWNING && .AVIATION... DESPITE NEARLY CONTINUOUS FALL OF RAIN...VFR CONDITIONS WILL CONTINUE THROUGH EARLY THIS MORNING. MAY SEE WINDS BRIEFLY BECOME VARIABLE AND GUSTY (AROUND 20 KNOTS) AS WEAKENING SQUALL LINE PUSHES THROUGH JOPLIN SHORTLY...AND SPRINGFIELD BEFORE 11Z. THUNDERSTORM CHANCES REALLY DIMINISHING BY THE MINUTE WITH JOPLIN LIKELY TO EXPERIENCE THE ONLY THREAT OF A ROGUE LIGHTNING STRIKE WELL BEFORE THE TERMINAL OPENS FOR BUSINESS. OTHERWISE...SUBSIDENCE IN THE WAKE OF MCV OVER SE KS WILL ONCE AGAIN LEAD TO A FAIRLY PLEASANT DAY ACROSS THE REGION. MAINLY EAST TO NORTHEAST LOW LEVEL FLOW WILL DOMINATE...BUT UNLIKE YESTERDAY FAIRLY MOIST MID LEVELS WILL LIKELY RESULT IN SCT-BKN CUMULUS DEVELOPMENT BY LATE MORNING/EARLY AFTERNOON. NEXT ROUND OF THUNDERSTORMS WILL DEVELOP THIS EVENING ALONG AND JUST NORTH OF QUASI-STATIONARY FRONT OVER CENTRAL/NRN ARKANSAS. MOST OF THIS ACTIVITY SHOULD REMAIN SOUTH OF THE TAF TERMINALS AND TWEB ROUTES. BOOKBINDER && .SGF WATCHES/WARNINGS/ADVISORIES... .MO...NONE .KS...NONE $$ WFO SGF mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WICHITA KS 236 PM CDT THU APR 22 2004 .DISCUSSION... MESOSCALE UPDATE...FOCUS IS ON SE KS AND CONVECTIVE POTENTIAL. RUC FCSTS MODEST < 800 J/KG CAPE, HOWEVER PROFILERS CONT TO SHOW IMPRESSIVE DIRECTIONAL/SPD SHEAR. RUC FCST SOUNDINGS ARE CONDUCIVE TO ELEVATED CONVECTION AND SUSPECT SVRL OF THE STORMS WILL PRODUCE PEA TO MARBLE HAIL, WITH SMALL COIN SIZED HAIL PSBL. HAZARDOUS OUTLOOK HAS BEEN UPDATED TO REFLECT SML SVR THREAT. HOWERTON .PREVIOUS DISCUSSION... 349 AM CDT THU APR 22 2004 ...MAIN FCST CONCERN SHIFTING FM SEVERE WEATHER TO HEAVY RAINFALL/FLOODING FOR MAINLY FRIDAY NIGHT INTO SATURDAY... WV IMAGERY SHOWS THE UPPER LOW DEVELOPING OVER NEVADA EARLY THIS MORNING. THE MODELS PROG THIS FEATURE TO DIG RATHER FAR SWD INTO THE SRN ROCKIES INTO FRIDAY. THIS WL KEEP THE MAIN SFC FRONTAL BOUNDARY SAGGING GRADUALLY A BIT FARTHER SOUTHWARD WITH TIME. WITH THE FRONT NOW EXPECTED TO REMAIN SOUTH OF OUR SRN KS COUNTIES, THE SEVERE POTENTIAL WL BE GREATLY DIMINISHED. TODAY-TONIGHT: NOT MUCH IN THE WAY OF LIFT/FORCING PROGGED TODAY, SO LOWERED THE POPS TO SLT CHC FOR MOST AREAS, EXCEPT CNTRL KS WHERE THEY MAY HAVE A LITTLE STRONGER LIFT FM THE UPR JET. EXTENSIVE CLOUD COVER SHOULD KEEP HIGHS A FEW-SVRL DEG COOLER THAN YESTERDAY FOR CNTRL-SCNTRL KS. LATER TONIGHT, THE ETA AND GFS PROG SUBSTANTIAL ISENTROPIC UPGLIDE PATTERN TO DEVELOP FM WRN KS INTO WRN OK AND TO A LESSER EXTENT S-CNTRL KS. WOULD EXPECT SOME OF THE SHOWERS/T-STORMS TO OUR SW TO ADVECT INTO S-CNTRL KS TOWARD MORNING. FRIDAY: ISENTROPIC LIFT PATTERN INCREASES AND BECOMES MORE WIDESREAD ACROSS THE FCST AREA. IN ADDITION, S-CNTRL/SERN KS WL BECOME IN THE RR QUADRANT OF THE UPPER JET BY EVENING. 850 MOISTURE CONVERGENCE INCREASES MORE OVER OUR SRN ZONES AS WELL. BOOSTED POPS TO LIKELY CATEGORY, ALTHOUGH HIGHEST POPS TARGETED FOR S-CNTRL/SERN KS. OVERCAST SKIES AND PCPN WL LIMIT HIGHS TO BELOW NORMAL (LOW 50S-LOW 60S). FRI NIGHT-SATURDAY: THIS IS THE TIME PERIOD WHERE INGREDIENTS ARE COMING TOGETHER FOR A POTENTIALLY SIGNIFICANT HEAVY RAINFALL/FLOODING EVENT FOR S-CNTRL/SERN KS. BOTH THE ETA AND GFS STRONGLY HINT AT A BACK-BUILDING UPPER JET FM THE UPR MIDWEST INTO THE CNTRL PLAINS. THIS OCCURS IN RESPONSE TO THE APPROACHING UPR LOW WITH COINCIDENT BUILDING UPR HEIGHTS DOWNSTREAM OVER THE OH VALLEY. PROLONGED UPR DIVERGENCE AND 850 MOISTURE FLUX/THETA-E ADVECTION LIKELY OVER MUCH OF S-CNTRL/SERN KS DURG THIS PD, WITH PRECIPITABLE WATER OF 1.20 TO 1.5 INCHES. WIDESPREAD 2-5 INCH RAINFALL AMOUNTS ARE CERTAINLY PLAUSIBLE (2 DAY TOTALS ENDING SAT PM). A BIT FAR OUT FOR A FLOOD WATCH, BUT WL HIGHLIGHT THE HVY RAIN/FLOODING POTENTIAL IN OUR HAZARDOUS WEATHER OUTLOOK. SUN-WED: UPR LOW WL PULL EAST OF REGION ON SUNDAY, WITH DRIER NW FLOW DEVELOPING INTO MONDAY. ECMWF AND GFS BEGIN TO SHOW SOME DIVERGENCE FM EACH OTHER BY WED LEADING TO SOME UNCERTAINTY IN THE UPR PATTERN FOR WED AND BEYOND. ATTM, LOOKS LIKE SUN-TUES SHOULD BE DRY WITH SEASONAL SPRINGTIME TEMPS. && .PRELIMINARY POINT TEMPS/POPS... WICHITA 66 51 61 48 / 20 40 70 80 HUTCHINSON 65 50 58 47 / 20 40 60 80 NEWTON 66 51 60 47 / 20 30 60 80 ELDORADO 66 52 61 48 / 20 30 70 80 STROTHER FIELD 70 53 62 48 / 20 50 70 80 RUSSELL 59 45 53 45 / 40 30 60 60 GREAT BEND 61 47 54 46 / 40 40 60 70 SALINA 64 46 58 46 / 40 30 60 70 MCPHERSON 64 49 58 47 / 20 30 60 80 COFFEYVILLE 73 55 64 50 / 20 50 70 90 CHANUTE 70 53 64 49 / 20 30 70 80 IOLA 70 53 64 49 / 20 30 70 80 && .ICT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ 9/CARUSO ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CARIBOU MAINE 400 PM EDT THU APR 22 2004 .SYNOPSIS...A COLD FRONT WILL MOVE THROUGH THE REGION LATE THIS AFTERNOON AND EARLY THIS EVENING. SCATTERED SHOWERS WITH GUSTY WINDS WILL ACCOMPANY THE FRONT. HIGH PRESSURE BUILDS OVERHEAD FOR FRIDAY WITH CLEAR SKIES NORTH AND SOME HIGH CLOUDS SOUTH. ANOTHER VIGOROUS COLD FRONT WILL PASS THROUGH ON SATURDAY FOLLOWED BY BRISK NORTHWEST WINDS. ANOTHER ROUND OF SHOWERS WILL OCCUR AS THE FRONT MOVES THROUGH ON SATURDAY...SOME OF THESE SHOWERS MAY CONTAIN SNOW ACROSS THE FAR NORTH. CANADIAN HIGH PRESSURE WILL BUILD ACROSS THE REGION ON SUNDAY WITH A FAIR WEATHER. DISCUSSION... SHORT RANGE: (TNGT THRU SAT NGT): COLD FRONT PROGRESSING THROUGH NW AROOSTOOK ATTM. LINE OF WEAK SHOWERS NOW THROUGH KFVE WITH 20KT GUST BUT LINE PRODUCED 30+KT GUST AT KYQB EARLIER...AND RUC SHOWING POTENTIAL FOR HIGHER GUST SHOULD ANY OF THE CELLS PULSE A BIT. SHOWER THREAT DMNSHS RAPIDLY TO SOUTH WHERE LAPSE RATES SMALLER... LESS MID LVL DYNAMICS...AND LOSS OF DAYTIME HEATING. FRONT SHOULD CLEAR COAST BY 03Z WITH CLEARING FOR EVERYONE BY LATE EVENING. NEXT WAVE PASSES SOUTH OF REGION BUT CLOSE ENUF TO SPREAD HIGH/MID CLOUD SHIELD OVER ALL BUT FAR NORTH TOMORROW. OTHERWISE DRY AND SEASONABLE. SAT SOLN...STILL A BIT IN FLUX...SHIFTING TODAY FROM A DVLPG COASTAL LOW TO A STG NRN STRM S/W AND SFC COLD FRONT. ECMWF THE LEAD FOR SUCH A SCENARIO WITH 12Z GFS/ETA NOW ON BOARD. POTENTIALLY A GOOD SHOT OF LATE SEASON WINDY ARCTIC AIR FOR SAT AFTN/SUN EVE. AGAIN...A LOT OF RUN-TO-RUN CHANGE SO SMOOTHED OUT THE SENSIBLE WEATHER A BIT IN GRIDS. LONG RANGE: (SUN-THU): THE RAPID SUCCESSION OF S/WVS FROM THE SHORT RANGE WILL EXTEND INITIALLY INTO THE LONG RANGE. SUN WILL BE DRY WITH DECREASING NW WINDS BY AFT. HI CLDS WILL INCREASE AHEAD OF THE NEXT S/WV ADVANCING EWRD FROM THE UPPER OH VALLEY/LOWER GREAT LKS BY LATE IN THE DAY AND EVE. PRECIP FROM GTHIS SYSTEM SHOULD ARRIVE TO MOST OF THE FA LATE SUN NGT...PERHAPS COLD ENOUGH OVR THE N TO MIX WITH WET SN AT TIMES. ANY MIXED PRECIP N SHOULD CHG TO ALL RAIN BY LATE MON MORN. AFTERWARDS...RAIN WILL LINGER INTO MON NGT AS THE SFC LOW MAKES ONLY SLOW E PROGRESS OFF THE NH COAST WITH AN UPPER LVL TROF AMPLIFYING OVR THE OH/TN VLYS. SOME DRYING ANTICIPATED FOR TUE AS THE LOW MOVES EAST INTO THE MARITIMES...BUT SKIES WILL REMAIN MOSTLY CLOUDY INTO WED WITH A FEW SHWRS POSSIBLE N AS THE UPPER TROF IN THE OH VLY MOVES E TOWARD THE FA. THE 12Z GFS RUN IS SHOWING MORE AMPLITUDE WITH THE OH/TN VLY UPPER TROF THEN THE LAST NGT'S...GFS IMPLYING THE POSSIBILITY OF ANOTHER COASTAL LOW THAT MAY FORM WELL OFF THE MID ATLC COAST AND POSSIBLY AFFECT SRN PORTIONS OF THE FA TUE NGT AND WED WITH SIGNIFICANT ATLC MOISTURE PRECIP. BUT FOR NOW...WE WILL LEAN WITH THE FLATTER AND DRIER 00Z GFS RUN WHICH MATCHED PRETTY WELL WITH OPERATIONAL RUNS OF THE ECMWF AND THE CAN MODELS. THU SHOULD FEATURE SUNNIER CONDITIONS AND MILDER HI TEMPS AS THE UPPER TROF BEGINS LIFTING OUT E OF THE FA. GENERALLY WENT WITH THE MEAN OF THE GFS ENSEMBLE MOS MEMBERS...EXCEPT COOLER FOR MON HI TEMPS DUE TO CLD CVR AND PRECIP ACROSS THE FA. MARINE: GENERALLY WENT WITH GFS WINDS AND WRN ATLC WW3 WAVE HTS DURING THE LONG RANGE PTN OF THE CWF. SCA WINDS ARE POSSIBLE FOR OUR WATERS ON MON AHEAD OF THE SFC LOW MOVING OFF THE NH COAST. AVIATION: PRIMARILY VFR CONDITIONS XPCTED AT TAF SITES WITH SCT-BKN CVRG SHWRS ACCOMPANIED BY GUSTY WINDS WITH COLD FRONTAL PASSAGE LATE THIS AFT INTO ERLY EVE. SKIES SHOULD SCT OUT OVR ALL TAF SITES LATE THIS EVE. .CAR...SCA FOR SEAS THIS EVE. SHORT RANGE: DKC LONG RANGE: VJN AVIATION: RN me AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HASTINGS NE 335 PM CDT THU APR 22 2004 .DISCUSSION...DOUBLE BARREL SHORTWAVE STRUCTURE CURRENTLY IMPACTED THE CWFA AND PLAINS REGION. PROFILERS DEPICT THIS WELL...WITH ONE WAVE OVER WESTERN NEBRASKA...AND ANOTHER SLIDING NORTH FROM NORTH CENTRAL AND NORTHEAST KANSAS. THIS SECOND WAVE HAS BROUGHT A STEADY LIGHT RAIN TO EXTREME NORTHERN KANSAS THE LAST FEW HOURS AND HAS FINALLY SHOWN SIGNS OF LIFTING NORTH. RUC/ETA DEPICTION SUGGEST THE NORTHWARD DRIFT WILL CONTINUE THIS EVENING...BUT EVENTUALLY THE WAVE GETS SHEARED AND WEAKENS BY LATE EVENING. ISENTROPIC LIFT WEAKENS AS A RESULT. FOR NOW...EXPECTED SCATTERED SHOWERS ACROSS A LARGE PART OF THE SOUTHERN CWFA THROUGH THE EVENING...BEFORE THEY GRADUALLY FADE AWAY BY LATE TONIGHT. FRIDAY WE ARE IN BETWEEN THESE INITIAL WAVES AND THE MAIN UPPER LOW PRESSURE...CURRENTLY IN UTAH. ETA REALLY CLEANS OUT ANY LOW CLOUDS EVEN WITH A NORTHEAST FLOW. DIURNAL GREATER WILL BE GREATER NORTH/EAST SECTIONS OF THE CWFA FRIDAY...AND LESS IN THE SOUTHWEST. FEW CHANGES TO PREVIOUS GRIDS WITH THIS IN MIND. RAINFALL SHOULD RETURN FROM SOUTHWEST TO NORTHEAST ACROSS THE AREA FRIDAY NIGHT AND SATURDAY WITH THE UPPER LOW EJECTING OUT OVER THE PLAINS. CHILLY CONDITIONS EXPECTED FRIDAY NIGHT AND EARLY SATURDAY...BUT WILL HOLD OFF ANY SNOW MENTION WESTERN ZONES. COLD CORE OF LOW GOES JUST WEST OF CWFA...AND IS ONLY ABOUT -22 AT 500 MILLIBARS. THICKNESS PARAMETERS ARE VERY MARGINALLY. POINT IS THIS IS NOTHING LIKE OUR SNOW EVENT LAST WEEK AND SNOW IS NOT EXPECTED. RAINFALL WILL LINGER ALL DAY SATURDAY ON THE ORDER OF A QUARTER INCH. ISOLATED THUNDERSTORM IS POSSIBLE...BUT STABILITY IS PRETTY MARGINAL. CONVECTION WILL BE MUCH MORE PREVALENT TO OUR SOUTHEAST. GOOD AGREEMENT FOR MONDAY THROUGH THURSDAY IN GENERAL. WARMING TEMPERATURES WILL BE THE MAIN STORY THROUGH WEDNESDAY AS THE CWFA RETURNS TO THE MIDDLE AND UPPER 70S TUESDAY...AND THE UPPER 70S TO LOWER 80S WEDNESDAY. WEDNESDAY COULD BE QUITE WARM WITH PRE-FRONTAL WARMING AHEAD OF THE NEXT WEATHER SYSTEM. EC/GFS HAVE SAME GENERAL TIMING OF FRONTAL BOUNDARY AT 168 HOURS. CMC SUGGESTS A SIMILAR PATTERN TO THE GFS AT 144 HOURS. ALL THIS SPELLS A LIKELY COLD FRONTAL PASSAGE BY EARLY THURSDAY. TIMING IS STILL SUBJECT TO CHANGE...AND HAVE ELECTED TO HOLD OFF ANY DAY 7 SMALL POPS AT THIS TIME. && .GID WATCHES/WARNINGS/ADVISORIES... .NE...NONE. .KS...NONE. && $$ MORITZ ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 303 PM EDT THU APR 22 2004 .SHORT TERM... A PERSISTENT...THOUGH RATHER UNORGANIZED MCS CONTINUES TO WORK ITS WAY EAST...ACROSS MIDDLE TN ATTM. SYSTEM IS EMBEDDED IN REASONABLY GOOD DEEP LAYER SHEAR W/35 KTS AT H7 AND AROUND 50 KTS AT H5. RUC AND WATER VAPOR IMAGERY SHOW THAT THE SYSTEM IS ALSO ASSOCIATED WITH A WEAK SRN STREAM SHORT WAVE. ALL OF THIS CAUSES SOME CONCERN THAT THE SYSTEM MAY MAKE IT INTO THE WRN CAROLINAS. HOWEVER...LARGE SCALE HGHTS WL CONTINUE TO RISE THIS EVENING ACROSS THE REGION IN RESPONSE TO HGHT FALLS FARTHER WEST ACROSS THE SRN ROCKIES AND HIGH PLAINS. THIS WL RESULT IN WEAKENING SHEAR. ALSO...GOES SOUNDER LI/S SHOW VERY WELL AN AREA OF GREATER STABILITY THAT EXTENDS FROM CNTRL GA...N INTO THE WRN CAROLINAS. THIS MOISTURE MINIMUM ALSO HAPPENS TO COINCIDE WITH AN AREA THAT IS CURRENTLY EXPERIENCING A MODERATE DROUGHT. THIS AREA OF LOWER DWPTS HAS PERSISTED FOR SEVERAL DAYS...AND I SUSPECT THAT IT HAS TO DO WITH THE DRY SOIL CONDITIONS IN THIS REGION. THEREFORE I SUSPECT THAT MCS WL NOT MAKE IT THIS FAR E...BUT WL KEEP A SLGT CHANCE POP IN THE MTNS THROUGH THE EVENING TO ACCOUNT FOR SOME REMNANT CONVECTION. HGHTS CONTINUE TO RISE ACROSS THE SE STATES ON TUE. THIS RESULTS IN AN AREA OF ENHANCED MID LEVEL WINDS ON THE N SIDE OF THE UPPER RIDGE...WITH GOOD SHEAR ACROSS TN/KY/WRN NC AND THE VIRGINIAS. IN OUR CASE...THE QUESTION IS INITIATION AND MOISTURE. OUTFLOW BNDRYS AND HIGH TERRAIN WL FAVOR SOME CONVECTIVE DEVELOPMENT OVER THE MTNS. HOWEVER...LACK OF DEEP LAYER CONVERGENCE AND DRY SOIL WL MAKE IT DIFFICULT TO POOL HIGHER DWPTS THIS FAR SOUTH. SPC HAS PULLED EVEN GENERAL THUNDER N OF OUR CWA FOR DAY 2. WON/T GO SO FAR AS TO REMOVE CONVECTION...BUT WL LIMIT POPS TO LOW CHANCE ACROSS THE NC MTNS. ETA HAS SFC DWPTS RISING INTO THE L60S E OF THE MTNS TMRW. HOWEVER... RUNNING REVERSE TRAJECTORIES ON THE HYSPLIT MODEL SHOW THAT THE SOURCE REGION FOR THE 1000 AND 1500 METER LAYER OVER THE UPSTATE TMRW IS THE FL PANHANDLE. THE TRAJECTORIES ALSO SINK ABOUT 500 M BEFORE ENTERING THE CWA. I HAVE MY DOUBTS ABOUT THE ETA/S DWPTS...AND WL KEEP ZONES E OF THE MTNS DRY. BACK DOOR COLD FRONT ARRIVES SAT AFTN. CAD IS FORCED BY A STRONG BUT TRANSITORY SHORT WAVE. THEREFORE...LIKE THE WAY THE ETA DRIVES THE FRONT THROUGH THE CWA SAT NGHT AND THEN MOVES THE HIGH QUICKLY OFFSHORE ON SUN...TURNING BNDRY LAYER FLOW BACK TO THE S. WL KEEP CHANCE POPS ACROSS JUST ABOUT ALL THE CWA SAT AFTN AND EVENING AS ETA HAS VERY GOOD SFC-850 MB CONVERGENCE LATE IN THE DAY OVER THE HEART OF THE CWA. GOOD LLVL CONVERGENCE AND MOISTURE POOLING SHOULD OVERCOME RIDGING ALOFT AND DRIVE SOME TSTM DEVELOPMENT. SUN POPS ARE MORE IFFY. DON/T WANT TO FLIP FLOP ON FORECAST...AND WHILE I WOULDN/T HAVE ADDED THEM IF THEY WERE NOT THERE...NOT CONFIDENT ENUF TO REMOVE THEM SINCE THEY ARE. .LONG TERM... EXTENDED FORECAST STARTS WITH COLD FRONT CROSSING AREA MON... SUPPORTING SCATTERED CONVECTION IN MODESTLY UNSTABLE AIR. DRYING TUE IN WAKE OF FRONT...WITH COOLING OFFSET BY DOWNSLOPE FLOW. WARMING WED/THU AS WARM ADVECTION ON BACK SIDE OF SURFACE RIDGE MOVES INTO AREA. && .PRELIMINARY POINT TEMPS/POPS... GSP 58 81 59 80 / 10 10 10 30 AND 58 81 58 82 / 10 10 10 30 CLT 59 81 59 79 / 10 10 10 30 HKY 57 80 57 78 / 10 20 20 30 AVL 52 79 54 75 / 20 30 20 40 && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ MCAVOY/07 sc