SOUTHEAST ARIZONA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TUCSON AZ 915 PM MST FRI MAY 9 2003 .SYNOPSIS...THE LOW PRESSURE SYSTEM THAT BROUGHT SOME WINDY CONDITIONS TO PARTS OF SOUTHEAST ARIZONA TODAY WILL MOVE WELL EAST OF THE REGION FOR LESS WIND OVER THE WEEKEND. HIGH PRESSURE WILL BUILD OVER THE DESERT SOUTHWEST FOR A WARMING TREND THROUGH EARLY NEXT WEEK. BY THE MIDDLE OF NEXT WEEK...ANOTHER LOW PRESSURE SYSTEM IS FORECAST TO MOVE THROUGH THE REGION BRINGING ONCE AGAIN SOME WIND AND SLIGHTLY COOLER DAYTIME TEMPERATURES. .DISCUSSION...BOTH THE WIND ADVISORY AND THE RED FLAG WARNING WORKED OUT WELL THIS AFTERNOON FOR EASTERN ZONES. AT THE DOUGLAS AIRPORT THE HIGHEST SUSTAINED WIND WAS 29 MPH WITH A GUST TO 41 MPH. AT FORT HUACHUCA THE HIGHEST WIND RECORDED WAS 28 MPH WITH A GUST TO 51 MPH. AT SAFFORD THE HIGHEST WIND WAS 26 MPH WITH A GUST TO 39 MPH. MIN RH'S WERE IN THE SINGLE DIGITS IN MANY LOCATIONS. SEVERAL OF THE RAWS SITES ALSO REACHED RED FLAG CRITERIA AS WELL. CURRENT WATER VAPOR IMAGERY AND RUC ANALYSIS SHOWS VORT CENTER ASSOCIATED WITH UPPER LEVEL SYSTEM OVER SOUTHERN UTAH AND EXTENDING BACK ACROSS THE GREAT BASIN AND INTO NORTH CENTRAL CALIFORNIA. THIS SYSTEM WILL CONTINUE TO MAKE PROGRESS TO THE EAST ACCORDING TO THE MODELS. BY LATE SATURDAY A FLAT RIDGE WILL BEGIN TO BUILD INTO THE WEST COAST...AND BY SUNDAY THE RIDGE WILL SHIFT EAST AND AMPLIFY ACROSS THE DESERT SW AND INTO THE NORTHERN ROCKIES. HEIGHTS WILL RISE SIGNIFICANTLY BY SUNDAY AND INTO MONDAY WITH LATEST ETA/NGM MOS GUIDANCE REFLECTING THIS...AND IS ADVERTISING HIGHS IN THE UPPER 80S TO LOWER 90S. CURRENT ZONES/GRIDS SHOW TEMPS FOR SUNDAY A BIT ON THE LOW SIDE COMPARED TO LATEST MOS NUMBERS SO WILL TWEAK GRIDS A BIT UPWARD TO REFLECT THE WARMING TREND...IF MAV NUMBERS COME IN WARMER THAN THE PREVIOUS RUN AS WELL. MOLLERE .TWC...NONE. $$ az WESTERN COLORADO & EASTERN UTAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 944 PM MDT FRI MAY 9 2003 COLD UPPER LOW CIRCULATION CENTERED OVER UTAH THIS EVENING. MAIN AREA OF PRECIPITATION EXTENDS FROM THE SOUTHERN UNCOMPAHGRE PLATEAU ACROSS THE CENTRAL MOUNTAINS TO AROUND RABBIT EARS PASS PER KGJX REFLECTIVITY. THE RUC ANALYSIS PLACES A VORTICITY LOBE JUST WEST OF THIS AREA OF PRECIPITATION WHICH MATCHES UP NICELY WITH WATER VAPOR IMAGERY. CYCLONICALLY CURVED UPPER JET STILL SUPPLYING SOME UPPER DIVERGENCE AS WELL. UPPER COLD CORE WILL MOVE ACROSS THE AREA OVERNIGHT WITH UNSTABLE LAPSE RATES CONTINUING. NORTHEAST FLOW SHOULD CONTINUE TO GIVE THE EASTERN UINTA MOUNTAINS A GOOD SHOT OF SNOW INTO THE LATE NIGHT HOURS. PRECIPITATION WILL BECOME MORE FOCUSED ACROSS THE NORTHERN MOUNTAINS OF WESTERN COLORADO LATE TONIGHT AND EARLY SATURDAY MORNING AS THE MID LEVEL FLOW BACKS AROUND TO THE NORTHWEST. WIDESPREAD SIGNIFICANT SNOW ACCUMULATIONS ACROSS THE UNCOMPAHGRE PLATEAU WILL BE WINDING DOWN THROUGH MIDNIGHT. GOING ADVISORIES AND WARNINGS LOOK GOOD. INCREASED SNOW AMOUNTS FOR THE NORTHWEST COLORADO VALLEYS 1 TO 2 INCHES IN THE EVENING UPDATE. LINDQUIST .GJT...WINTER WEATHER ADVISORY TONIGHT FOR UTAH ZONE 23 AND CO ZONE 017. ...WINTER WEATHER ADVISORY TONIGHT THROUGH NOON SATURDAY FOR CO ZONES 003-005-009-010-012. ...WINTER STORM WARNING FOR CO ZONES 004-013. co SOUTHWEST IDAHO/SOUTHEAST OREGON AREA FORECAST DISCUSSION 400 PM MDT FRI MAY 9 2003 MOISTURE PLUME OVER SE OREGON AND SW ID MOUNTAINS IS WEAKENING WITH COLDEST ENHANCED CLOUD TOPS OVER HARNEY COUNTY WITH A RUC ANALYZED VORT MAX. THE OREGON PORTION WILL BRING NUMEROUS SHOWERS THERE MAINLY BEFORE MIDNIGHT WITH SNOW LEVELS DOWN TO 5500 FEET FOR 1 TO 4 INCHES OF SNOW MAINLY IN THE STEENS MTS. BROAD UPPER TROF LINGERS OVER THE WEST BUT THE ABUNDANT RAIN PRODUCING LOW SHIFTS AWAY LEAVING A SHEARED VORT AXIS ACROSS N NV INTO CENTRAL OREGON. THIS FEATURE IS EXPECTED TO FOCUS SCT-NMRS SHOWERS WITH ONLY 20-40 POPS ELSEWHERE THRU SATURDAY. ON SATURDAY AN UPPER TROF PIVOTS OVER OREGON AND FAR SW ID OVERRIDING A 308K H7 WARM MOIST THETA-E RIDGE FOR LIKELY POPS THERE SATURDAY NIGHT. THESE FEATURES SHIFT NE ON SUNDAY FOR HIGHER POPS ACROSS N BAKER CO AND NRN WEST CENTRAL MTS. THE 18Z GFS IS ON TRACK WITH THESE FEATURES AS IN THE 12Z RUN OF THE GFS. MOIST BAND IS NOT EVIDENT IN THE ETA WHOSE HEIGHTS/H5 ARE 30-60 M HIGHER AND HAVE NOT GONE WITH DRY SOLN BUT UNCERTAINTY IS THERE SO SUNDAY COULD TURN OUT DRY AND AROUND 5F WARMER. SW U.S. RIDGE BULGES UP TOWARDS THE GT BASIN SUNDAY NIGHT - MONDAY SO HAVE GONE DRY SOUTH AND LOW POPS NORTH...FAVORING MTS...AND WARMED UP HIGHS. SIMILAR PTTN FOR TUESDAY BUT A BUT MILDER AGAIN. IN THE WED-FRI PERIOD AREA IS UNDER SPLITTY FLOW ALOFT. THIS WOULD TREND TOWARDS DRY BUT THE GFS DOES HAVE SOME QPF ACROSS AREEA THURSDAY. PLAN TO GO WITH CURRENT DRY/PERSISTENCE FCST FOR THE PERIOD. .BOI...NONE. $$ = id AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 1259 PM EST FRI MAY 9 2003 18Z AVIATION DISCUSSION... SATELLITE PICTURE SHOWING THAT THE LOW CLOUDS SHOULD RISE TO VFR IN AN HOUR OR SO AT FWA AND LATE THIS AFTERNOON/EARLY EVENING AT SBN. WINDS ARE EXPECTED TO SHIFT TO THE SOUTHWEST AROUND 21Z WHEN THAT WARM FRONT PUSHES NORTH OF US. THE CLOUDS SHOULD THEN LOWER AGAIN AROUND MIDNIGHT TONIGHT WITH THE WINDS DYING DOWN SATURDAY MORNING. LOOKS LIKE THERE IS A CHANCE FOR SOME RAIN TONIGHT BUT THE POPS ARE LOW SO LEFT IT OUT FOR NOW. BML FORECAST DISCUSSION FOR UPDATE AT 1015 AM... OVERNIGHT MCS HAS COOLED AND STABILIZED LOWER LEVELS THIS MORNING. DEBRIS CLOUDS STILL HANGING OVER AREA AND HAVE BEEN SLOW TO MIX OUT. THUS WARM FRONT HAS REMAINED SOUTH OF COUNTY WARNING AREA. PARTLY CLOUDY SKIES SOUTH OF FRONT HAS HELPED TO STRENGTHEN WARM FRONT...WITH TEMPERATURES ALREADY APPROACHING UPPER 70S AND DEWPOINTS IN THE LOWER 70S. AS MORE BREAKS DEVELOP IN CLOUD COVER TODAY...MIXING SHOULD ALLOW SURFACE WINDS TO GO MORE SOUTHWEST AND THIS SHOULD HELP FRONT MOVE NORTH. LATEST ETA AND RUC MODELS INDICATING THIS AND HAVE TO THINK WITH BREAKS BEGINNING TO OCCUR ALREADY THAT THIS WILL OCCUR. ATMOSPHERE PROGGED TO BECOME VERY UNSTABLE SOUTH OF FRONT AND THIS IS VERY REASONABLE GIVEN TEMP/DEWPOINTS IN CENTRAL INDIANA. OTHER THAN FRONT...NO STRONG TRIGGER IN FORM OF SHORT WAVE OR COOLING ALOFT. 12Z ILX SOUNDING HAD AN IMPRESSIVE CAP AROUND 600MB AND WAS QUITE DRY. WITH ALL THIS IN MIND...WILL CONTINUE OPTIMISTIC FORECAST OF BECOMING PARTLY CLOUDY. THIS WILL ALLOW INSTABILITY TO INCREASE AND WILL KEEP CHC POPS WITH SEVERE WORDING THIS AFTERNOON SINCE ANY STORM THAT DEVELOPS WILL HAVE A HIGH PROBABILITY OF BECOMING SEVERE NEAR AND SOUTH OF FRONT. WILL LOWER TEMPERATURES A TAD ACROSS THE NORTH AND ESPECIALLY NORTHEAST TO ACCOUNT FOR SLOWER NORTHWARD MOVEMENT. SOUTHERN AREAS WILL NOT CHANGE MUCH AS THEY WILL QUICKLY JUMP WITH FRONTAL PASSAGE. NO CHANGES TO LATER PERIODS AS NEXT WAVE IN SOUTHERN PLAINS WILL LIKELY MOVE ACROSS REGION TONIGHT...CREATING ANOTHER BOUT OF OVERNIGHT THUNDERSTORMS. ZONE/GRID UPDATE OUT SHORTLY. .IWX... IN...NONE. MI...NONE. OH...NONE. LASHLEY in AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE NORTHERN INDIANA 1015 AM EST FRI MAY 9 2003 OVERNIGHT MCS HAS COOLED AND STABILIZED LOWER LEVELS THIS MORNING. DEBRIS CLOUDS STILL HANGING OVER AREA AND HAVE BEEN SLOW TO MIX OUT. THUS WARM FRONT HAS REMAINED SOUTH OF COUNTY WARNING AREA. PARTLY CLOUDY SKIES SOUTH OF FRONT HAS HELPED TO STRENGTHEN WARM FRONT...WITH TEMPERATURES ALREADY APPROACHING UPPER 70S AND DEWPOINTS IN THE LOWER 70S. AS MORE BREAKS DEVELOP IN CLOUD COVER TODAY...MIXING SHOULD ALLOW SURFACE WINDS TO GO MORE SOUTHWEST AND THIS SHOULD HELP FRONT MOVE NORTH. LATEST ETA AND RUC MODELS INDICATING THIS AND HAVE TO THINK WITH BREAKS BEGINNING TO OCCUR ALREADY THAT THIS WILL OCCUR. ATMOSPHERE PROGGED TO BECOME VERY UNSTABLE SOUTH OF FRONT AND THIS IS VERY REASONABLE GIVEN TEMP/DEWPOINTS IN CENTRAL INDIANA. OTHER THAN FRONT...NO STRONG TRIGGER IN FORM OF SHORT WAVE OR COOLING ALOFT. 12Z ILX SOUNDING HAD AN IMPRESSIVE CAP AROUND 600MB AND WAS QUITE DRY. WITH ALL THIS IN MIND...WILL CONTINUE OPTIMISTIC FORECAST OF BECOMING PARTLY CLOUDY. THIS WILL ALLOW INSTABILITY TO INCREASE AND WILL KEEP CHC POPS WITH SEVERE WORDING THIS AFTERNOON SINCE ANY STORM THAT DEVELOPS WILL HAVE A HIGH PROBABILITY OF BECOMING SEVERE NEAR AND SOUTH OF FRONT. WILL LOWER TEMPERATURES A TAD ACROSS THE NORTH AND ESPECIALLY NORTHEAST TO ACCOUNT FOR SLOWER NORTHWARD MOVEMENT. SOUTHERN AREAS WILL NOT CHANGE MUCH AS THEY WILL QUICKLY JUMP WITH FRONTAL PASSAGE. NO CHANGES TO LATER PERIODS AS NEXT WAVE IN SOUTHERN PLAINS WILL LIKELY MOVE ACROSS REGION TONIGHT...CREATING ANOTHER BOUT OF OVERNIGHT THUNDERSTORMS. ZONE/GRID UPDATE OUT SHORTLY. .IWX... IN...NONE. MI...NONE. OH...NONE. LASHLEY in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WICHITA KS 703 PM CDT FRI MAY 9 2003 ...MESOSCALE UPDATE... PRIND TSTMS WL CONT TO DVLP THRU 03Z. MODIFIED RUC SNDGS IN SE KS YIELD ABT 2500 CAPE/80 CIN. ERY ON, MAIN THREAT SHUD BE MAINLY WIND AND MARGINAL HAIL. HOWEVER AS LLVL WNDS BACK/INCR THRU SUNSET, BELIEVE THREAT FOR LARGER HAIL/TORNADOES WL INCR. CURRENT MEAN STORM MOTION IS ABT 230/50KTS. RIGHT MOVERS SHUD TRACK CLOSER TO 270/35KT. BELIEVE DEEPER MSTR CURRENTLY OVR SE KS WL ADVECT NW AS LLVL WNDS INCR/BACK, SPREADING THREAT OF TSTMS/SVR WX NW WITH RETREATING DRYLN. HOWERTON ---------------------------------------------------------------- 334 PM CDT FRI MAY 9 2003 TONIGHT-EARLY SATURDAY: CHANCE OF ADDITIONAL CONVECTION OF IMMEDIATE CONCERN TONIGHT INTO EARLY SATURDAY. APPEARS MAIN FOCUS WILL AGAIN BE OVER SOUTHEAST KANSAS ALONG SURFACE BOUNDARY...WHICH HAS CREPT A BIT NWRD SINCE 12Z. WILL KEEP SEVERE WORDING IN SERN ZONES WITH INITIATION AFTER 23Z OR SO. SATURDAY: GOOD WRAPAROUND MOISTURE AS LOW DEPARTS TO THE NORTHEAST. SOME ADDITIONAL PRECIPITATION POSSIBLE MAINLY EARLY...BUT EXPECT MAINLY MORE SHOWERY TYPE WEST WITH SOME TRW FURTHER TO THE EAST. SATURDAY NIGHT-SUNDAY: SURFACE HIGH TO SLIDE SWD WITH CLEARING SKIES AND SLIGHTLY COOLER TEMPERATURES...ALTHOUGH EXPECT WINDS TO INCREASE DURING THE DAY. MONDAY-FRIDAY: UPPER FLOW BECOMES MORE ZONAL IN THE WAKE OF DEPARTING SYSTEM WITH SOME WEAK RIDGING AHEAD OF NEXT SYSTEM BY TUESDAY NIGHT. WILL RETAIN MENTION OF PRECIPITATION TUESDAY NIGHT THROUGH THURSDAY AS SURFACE LOW INTENSIFIES TO THE SOUTH AND SFC FRONT DRAGS ACROSS THURSDAY NIGHT. WILL KEEP FRIDAY DRY FOR NOW AS FCST AREA REMAINS BETWEEN SYSTEMS. FCSTID = 16 ICT 61 74 48 70 / 40 30 10 5 HUT 57 71 46 68 / 30 30 10 5 EWK 61 74 47 69 / 40 30 10 5 EQA 64 76 48 68 / 50 30 10 5 WLD 65 79 51 73 / 40 30 10 5 RSL 52 64 44 65 / 20 20 10 5 GBD 53 64 45 64 / 20 20 10 5 SLN 56 68 46 68 / 30 30 10 5 MPR 60 73 47 69 / 40 30 10 5 CFV 68 82 52 73 / 60 30 10 5 CNU 67 81 51 68 / 60 30 10 5 K88 67 81 50 67 / 60 30 10 5 .ICT...NONE. ks SOUTHEAST MICHIGAN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1007 PM EDT FRI MAY 9 2003 MAIN CONCERN HERE FOR THE OVERNIGHT HOURS WILL BE CONVECTIVE POTENTIAL AND INCLUDING POSSIBLE SEVERE. 01Z SURFACE ANALYSIS SHOWS WARM FRONT /BASED ON THERMAL CONSIDERATIONS/ EXTENDING SOUTHEAST FROM OCCLUDED FRONT NEAR ORD TO GSH/FWA/AOH LINE. THIS PLACES ENTIRE CWA ON COOL SIDE OF WARM FRONT. 00Z DTX SOUNDING SHOWS...AS MIGHT BE EXPECTED IN THIS REGIME...ZERO SFC BASED CAPE. FRONTAL INVERSION IS FAIRLY DEEP AT 5K FEET. LIFTING PARCEL FROM MAX THETA-E AROUND 840MB YIELDS LITTLE CAPE AND AN LI OF 0.65. 00Z RUC SHOWS TSRA OVER INDIANA DEVELOPING IN 850MB THETA-E RIDGE AND LOW LEVEL CONVERGENCE. OVER NEXT COUPLE OF HOURS THIS RIDGE WILL EXTEND INTO FAR SOUTHEAST LOWER. ALTHOUGH ELEVATED INSTABILITY NOT TOO IMPRESSIVE HERE AT DTX...HIGHER ELEVATED INSTABILITY LIKELY SOUTH...AND WITH LOW LEVEL FLOW PROGGED TO REMAIN SW OVERNIGHT /30-35 KNOTS INDICATED ON ILX VWP 3-5K FEET/...GREATER INSTABILITY OVER INDIANA WILL BE ADVECTED INTO THE REGION...WITH ANY STORMS THAT MAKE IT INTO SE LOWER BECOMING ELEVATED. /WARM FRONT SHOULD MOVE EVER SO SLOWLY NORTH OVERNIGHT...BUT CWA LOOKS TO REMAIN ON THE COOL SIDE THROUGH THE OVERNIGHT HOURS./ CONVECTIVE ACTIVITY OVER INDIANA AND INTO OH LOOKS LIKE IT WILL SKIRT THE SOUTHERN EDGE OF THE CWA. FURTHERMORE...ANY MCS-TYPE DEVELOPMENT OVER CENTRAL IL...WOULD LOOK TO TRACK SLIGHTLY NORTH OF EAST DUE EAST /PER 300-850MB THICKNESS-WIND CONSIDERATIONS/. BOTH OF THESE FACTORS BRING TSRA CLOSE ENOUGH TO MAINTAIN CHANCE POPS OVERNIGHT ACROSS SOUTHERN THIRD OF CWA. AS FOR SEVERE POTENTIAL...CANNOT RULE OUT AN ISOLATED STORM CROSSING WARM FRONT AND PRODUCING SOME MARGINAL SEVERE WX. GIVEN DEPTH OF FRONTAL INVERSION WOULD EXPECT THAT MOST PROBABLE SEVERE WX TO BE HAIL. HWO WILL CALL FOR JUST AN ISOLATED POSSIBILITY OF SEVERE ALONG AND SOUTH OF I 94. OKEEFE AFTERNOON DISCUSSION FOLLOWS... AN UPPER LOW ROTATING OVER THE UPPER MISSISSIPPI VALLEY HAS AN ASSOCIATED SURFACE LOW CENTERED NEAR MINNEAPOLIS WITH AN OCCLUDED FRONT EXTENDING INTO CHICAGO THEN BACK INTO THE MID MISSISSIPPI VALLEY. MEANWHILE...A WARM FRONT EXTENDS FROM NEAR CHICAGO EAST-SOUTHEAST INTO CENTRAL OHIO. SOUTH OF THIS BOUNDARY...THE AIRMASS IS QUITE UNSTABLE AS TEMPS HAVE RISEN INTO THE LOWER 80S AND SURFACE DEWPOINTS ARE CURRENTLY IN THE LOW 70S. SUBSTANTIAL DRY AIR ABOVE THE BOUNDARY LAYER AND A CAPPING INVERSION HAS THUS FAR PREVENTED CONVECTION FROM DEVELOPING ALONG THE BOUNDARY. CONVECTION IS HOWEVER BEGINNING TO DEVELOP IN SOUTHERN INDIANA ALONG THE LEADING EDGE OF THE HIGHER 850-700MB MOISTURE. ANOTHER UPPER LOW OVER UTAH WILL BE A KEY PLAYER IN THE WEATHER OVER THE GREAT LAKES BY THE END OF THE WEEKEND AS A SIGNIFICANT SPRING STORM SYSTEM IS EXPECTED TO MOVE INTO THE AREA. THIS SYSTEM WILL BE THE MAIN FORECAST CONCERN THIS PACKAGE. THE 12Z MODEL SUITE SHOW THE UPPER CIRCULATION OVER UTAH LIFTING NORTHEAST INTO THE SOUTHERN PLAINS ON SATURDAY...THEN LIFTING INTO THE WESTERN GREAT LAKES SATURDAY NIGHT...CARVING OUT A DEEP UPPER LOW OVER THE REGION ON SUNDAY. THIS WILL LEAD TO RAPID CYCLOGENESIS OVER THE MISSISSIPPI VALLEY/WESTERN LAKES SATURDAY NIGHT...SENDING A STRONG SURFACE COLD/OCCLUDED FRONT THROUGH SOUTHEAST MICHIGAN SUNDAY MORNING. THE ONLY MAJOR DIFFERENCES AMONG THE MODEL SOLUTIONS IS TIMING OF THE FRONT. THE GFS HAS THE FRONT THROUGH THE AREA BY 12Z...WHILE THE ETA TAKES IT THROUGH DURING THE MORNING. THE UKMET AND CANADIAN LIE IN BETWEEN THE TWO AS FAR AS TIMING. GIVEN THE DEEPENING UPPER LOW AND ITS SLIGHT NEGATIVE TILT...PREFER THE FARTHER WEST AND SLOWER ETA SOLUTION. FOR TONIGHT...I WILL CONTINUE TO CARRY A LOW CHANCE FOR SHOWERS AND THUNDERSTORMS SOUTH OF M-59 AS THE WARM FRONT SLOWLY ADVANCES NORTH THIS EVENING. INCREASING INSTABILITY SOUTH OF THE BOUNDARY MAY BE ENOUGH TO BREAK THROUGH THE CAP. WITH NO FORCING ACROSS THE NORTH AND ONLY MODEST 850MB THETA E RIDGING PASSING THROUGH THIS EVENING...I WILL KEEP THE NORTHERN COUNTIES DRY. CONVECTION SHOULD DEVELOP OVER THE MID MISSISSIPPI VALLEY TONIGHT ON THE NOSE OF A 50 KT LOW LEVEL JET OVER THE SOUTHERN PLAINS...FORCED BY NOCTURNAL COOLING AND IN RESPONSE TO A TIGHTENING PRESSURE GRADIENT RESULTING FROM THE MID LEVEL WAVE. THIS WIDESPREAD ACTIVITY SHOULD REMAIN WELL SOUTH OF THE FORECAST AREA. HOWEVER...I WILL MAINTAIN LOW CHANCES FOR SHOWER AND THUNDER ACROSS THE FAR SOUTH AS THE 850MB THETA E ADVECTION STRENGTHENS OVERNIGHT. ON SATURDAY...REMNANTS OF THE WARM FRONT SHOULD LINGER OVER THE FORECAST AREA. THIS WILL PROVIDE A FOCUS FOR POSSIBLE CONVECTIVE DEVELOPMENT. INSTABILITY WILL RELY HEAVILY ON HOW MUCH CLOUD COVER FROM CONVECTION TO THE SOUTHWEST WILL LINGER OVER THE REGION. AT THIS POINT...EXPECT MOST OF THE CLOUD DEBRIS TO BE SOUTH OF THE STATE. MODIFIED ETA SOUNDINGS FOR 77/66 YIELDS 2K J/KG CAPE. THIS ALONG WITH 0-6KM SHEAR NEAR 30 M/S MAY BE ENOUGH TO ALLOW STRONG TO SEVERE THUNDERSTORMS DURING THE AFTERNOON AND EVENING. MORE WIDESPREAD CONVECTION WILL OCCUR SATURDAY NIGHT IN ADVANCE OF THE MID LEVEL WAVE AND ASSOCIATED SURFACE FRONT. COPIOUS MOISTURE TRANSPORT OVERNIGHT WILL ALLOW PRECIPITABLE WATER VALUES TO APPROACH 1.8 INCHES. SO A PERIOD OF HEAVY RAINFALL IS DEFINITELY POSSIBLE. POTENT MID LEVEL DRY SLOT LATE SATURDAY NIGHT INTO EARLY SUNDAY WILL ADD TO NEGATIVE BUOYANCY POTENTIAL FOR STRONG THUNDERSTORM DOWNDRAFTS. SURFACE BASED CAPE ON THE ORDER OF 1500 J/KG AHEAD OF THE FRONT ALONG WITH STRONG UNIDIRECTIONAL SHEAR WILL LIKELY LEAD TO THE DEVELOPMENT OF A SQUALL LINE OVER THE AREA. HIGH HELICITY VALUES ALONG THE OCCLUDED FRONT WILL ALSO POSE A THREAT FOR SUPERCELLS. SO SEVERE WEATHER LOOKS VERY LIKELY LATE SATURDAY NIGHT INTO EARLY SUNDAY MORNING. MUCH COLDER AIR WILL FILTER INTO THE REGION ON SUNDAY IN THE WAKE OF THE FRONT. STRONG SUBSIDENCE/ISENTROPIC DESCENT AND MIXING HEIGHTS NEAR 5K FEET MAY ALLOW 40-45 KT WINDS TO MIX DOWN TO THE SURFACE. THUS A HIGH WIND ADVISORY MAY BE NEEDED FOR SUNDAY AFTERNOON/EVENING. I WILL REMOVE POPS ON SUNDAY AFTERNOON AS A STRONG MID LEVEL DRY SLOT WORKS ACROSS THE AREA BEHIND THE SURFACE FRONT. DEEP MOISTURE WRAPS BACK AROUND THE OCCLUDED SURFACE SYSTEM SUNDAY NIGHT AS IT MEANDERS ACROSS THE NORTHERN LAKES REGION THROUGH MONDAY. THUS I WILL BRING BACK THE CHANCE FOR SHOWERS SUNDAY NIGHT INTO MONDAY. I WILL KEEP MAX TEMPS IN THE 50S ON MONDAY...ALTHOUGH WITH THE COLD AIR WRAPPING AROUND THIS SYSTEM AND ALL THE CLOUD COVER...HIGHS MAY NOT MAKE IT OUT OF THE 40S. FOLLOWING THE DEPARTURE OF THE UPPER TROUGH TO THE EAST BY MID WEEK...MODEL SOLUTIONS ARE INDICATING A HIGH AMPLITUDE SPIT FLOW REGIME OVER THE REGION...WITH AN UPPER RIDGE BUILDING ACROSS THE NORTHERN LAKES AND A TROUGH BUILDING INTO THE OHIO VALLEY. THE GFS IS MUCH MORE AMPLIFIED WITH THESE FEATURES THAN THE EUROPEAN OR CANADIAN SOLUTIONS. ENSEMBLE MEANS SUPPORT A MUCH LESS AMPLIFIED PATTERN AS WELL. THUS...WEAK HIGH PRESSURE AND DRY CONDITIONS SHOULD REMAIN OVER THE AREA THOUGH THE END OF THE WEEK. TEMPERATURES SHOULD SLOWLY REBOUND TO NEAR NORMAL BY THE END OF THE WEEK AS THICKNESSES INCREASE. .DTX...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 MARQUETTE MI 925 PM EDT FRI MAY 9 2003 00Z RAOBS/WV LOOP AND RUC ANLSYS SHOW MEAN UPR TROF OVR THE WRN CONUS WITH RDG OVR THE SE TO SW OF CUTOFF LO OVR THE CNDN MARITIMES. FAIRLY POTENT SHRTWV/H5 VORT LOBE/SFC LO WHICH HAS MOVD INTO MN HAS WEAKENED CONSIDERABLY OVR THE LAST COUPLE OF HRS (SFC LO PRES GOING FM 999MB AT 21Z TO 1003MB AT 00Z) AS SYS MOVG NE OUT OF MEAN TROF AND INTO HUDSON BAY HI PRES AND DRIER ELY LLVL FLOW ON ITS SRN FLANK OVR THE NRN GRT LKS THAT LIES W OF CUTOFF LO OVR THE CNDN MARITIMES. ASSOCIATED WARM FNT XTNDS ESE FM SFC LO IN NCNTRL MN INTO NCNTRL WI...BUT REMNANTS OF SHRA/TSRA BAND WHICH IMPACTED CWA THIS MRNG/AFTN HAS IS NOW OVR LK SUP MORE COINCIDENT WITH H85 WARM FNT. JUST ISOLD -SHRA LINGER OVR CWA WITH OVC SKIES IN ELY FLOW/INCRSGLY SHALLOW COLD WEDGE N OF SFC WARM FNT. COMBINATION OF DNVA BEHIND H5 VORT LOBE/DVLPMNT OF SUBSIDENCE INVRN ARND H8 PER 00Z GRB/MPX SDNGS AND CONSIDERABLE DRY ADVCTN NOTED ON 00Z RAOBS ABV H8 HAS CONTRIBUTED TO COLLAPSE OF PCPN OVR CWA DESPITE LINGERING LLVL MSTR DEPICTED BY SFC OBS AS WELL AS LLVLS OF GRB AND MPX SDNGS. WEAK COLD FNT TO S OF MN SFC LO PRES HAS MOVD E OF MPX...AND DRIER WLY FLOW TENDING TO OCCLUDE WARM FNT...WHICH IS HAVING A HARDER AND HARDER TIME MOVG NE INTO DRIER/RAIN COOLED ELY FLOW OVR CWA. DESPITE DRYING BEHIND FNT...CONSIDERABLE LO CLD REMAINS. ANOTHER SHRTWV NOTED MOVG NE INTO SW MN IN WSWLY FLOW E OF MEAN WRN TROF...BUT OVERWHELMING MID LVL DRY AIR HAS PREVENTED ANY PCPN WITH JUST WEAK LLVL CNVGC ALG SFC COLD FNT. MAIN FCST CONCERNS TNGT REVOVLE ARND PCPN CHCS ASSOCIATED WITH APRCHG WARM FNT AND THEN POTENTIAL FOR FOG. 18Z ETA/21Z RUC SHOW MN SHRTWV/SFC LO DRIFTING SLOWLY N OVRNGT AND TENDING TO SLOWLY FILL. ALTHOUGH SHRTWV NOW MOVG INTO SW MN PROGGED TO MOVE TOWARD CWA OVRNGT...MODELS SHOW SHRTWV TENDING TO SHEAR OUT SO THAT DRY ADVCTN OVERWHELMS ANY MOISTENING DUE TO ASSOCIATED QVECTOR CNVGC/UVV WITH RESULT THAT MODEL FCST SDNGS SHOW LWRG/ STRENGTHENING SUBSIDENCE INVRN. MODELS ALSO HINT THAT WEAKENING OCCLUDED FNT WL DRIFT SLOWLY NE INTO CWA AND UNDERGO FRONTOLYSIS. THIS SCENARIO SUPPORTS MODEL FCSTS OF LTL OR NO QPF DURG OVRNGT PD...SO WL KEEP ZNS PCPN FREE ONCE LINGERING ISOLD -SHRA END. AS FOR FOG CHCS...SUSPECT SC CIGS WL LINGER MOST OF NGT AND RESTRICT SFC COOLING/DIURNAL TEMP FALL FM CURRENT READINGS SO THAT FOG WL NOT BCM A SGNFT PROBLEM. LLVL DRY ADVCTN DEPICTED IN H100-85 LYR BEHIND WEAKENING OCCLUDED FNT WL ALSO HINDER FOG CHCS. BUT COMBINATION OF PARTIAL CLRG ASSOCIATED WITH THIS DRY ADVCTN AND WEAKENING PRES GRADIENT/SFC WND ARND FILLING LO TO THE W WITH RA MOISTENED AIR STILL WARRANT MENTION OF PTCHY FOG DVLPMNT. OVERALL...GOING FCST HAS SCENARIO WELL IN HAND...SO NO CHGS NECESSARY ATTM. KC AFDMQT FM DAYSHIFT FOR LATER PDS... SAT...TEMP FCST FOR SAT COULD BE TRICKY. WITH OCCLUDED FRONT LINGERING TO SOUTH WE MAY STAY UNDER MORE CLDS ESPECIALLY IN THE MORNING. ALTHOUGH WITH MODELS INDICATING WK RDGG BY AFT AHD OF MORE SIGNIFICANT SHRTWV APPROACHING FM SOUTH...WILL GO ALONG WITH ETA FCST SNDGS AND ANTICIPATE INCREASING SUBSIDENCE AND SOME AFT SUN. WK SFC GRAD WILL ALLOW LAKE BREEZES TO DVLP KEEPING SHORELINES COOLER...WHILE INLAND AREAS WILL REACH 65 TO 70 AS 850 MB TEMPS OF 6C-10C MIX TO SFC. SAT NIGHT INTO SUN...MODELS LOOK TO BE DELAYING SYSTEM AS UPR TROF BECOMES MORE AMPLIFIED TO THE WEST. WHILE THERE ARE SOME MDL DIFFERENCES AVN A BIT QUICKER AND NOT AS DEEP WITH SYSTEM THAN ETA/UKMET...ALL MODELS SIMILAR WITH TRACK OF SFC LOW BRINGING IT UP THROUGH LAKE MICHIGAN SAT NIGHT TO NR STRAITS BY SUN MORNING. GIVEN DELAYED ARRIVAL OF PCPN PER MODELS...HAVE TAKEN OUT SHRA/TSRA FOR SW ZONES ERY SAT EVNG AND BACK UP TIMING OF SHRA TO MAINLY LATE SAT NIGHT INTO SUN. STRENGTH OF DYNAMICS...WITH STRONG UPR LVL DIV IN LFQ OF INCOMING 120 KT 3H JET MAX AND DEEP LYR QVECTOR CONV...STILL WARRNAT CATEGORICAL POPS. BEST INSTABILITY SHOULD STAY CLOSEST TO TRACK OF SFC LOW...WHICH MODEL INSTABILITY PARAMETERS SEEM TO INDICATE. MODELS SHOW 8H THETA-E RDG INTO ERN HALF ZONES WHERE SHOWALTER INDICES ALSO ARE NR 0C. KEPT TSRA MENTION EAST EARLY SUN...WHERE POCKET OF INSTABILITY FCST TO LINGER EARLY. SUN NIGHT INTO MON...DEEP SFC LOW BEGINS TO PULL AWAY AS STRONG CAA BEHIND IT WILL BRING FALLING TEMPS FROM WEST TO EAST WITH GUSTY NW WINDS. GIVEN WRAPAROUND MOISTURE AND DEEP Q-VECT CONV LINGERING INTO SUN EVNG KEPT IN CAT POPS ALTHOUGH EXPECT PCPN TO BCM SCT LATE SUN NIGHT AS BETTER DYNAMICS PULL EAST. GFS STILL SHOWS 1000-850 THICKNESSES FALLING TO AROUND 1305M ...AND 0C HEIGHT FALLING BLO 1K FT AGL (PER 12Z GFS BUFR SNDGS)...WHICH COULD BRING SOME -SHSN MIX OVER HIGHER TERRAIN AREAS OF WEST/CNTRL UPR MI SUN NIGHT INTO MON MORNING...AS PER GOING FCST. .EXTENDED(TUE-FRI)... OPERATIONAL MODELS AND ENSEMBLES INDICATE GRADUAL BREAK IN BLOCKING PATTERN BY MID TO LATE NEXT WEKK. WILL KEEP IN CHC OF SHOWERS FOR ERN COUNTIES TUE MORNING WITH LINGERING CLOSED LOW OVR THE ERN LAKES. MODELS THEN SHOW UPR RDG GRADUALLY BLDG IN FROM WEST BY MIDWEEK WITH DRY CONDITIONS FOR WED-FRI AND A MODEST WARMING TREND BY END OF WEEK AS INLAND TEMPS SHOULD REACH AGAIN INTO THE LOW TO MID 70S. VOSS .MQT...NONE. mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 853 PM EDT FRI MAY 9 2003 ...LOOKS LIKE LITTLE REAL THREAT FOR CONVECTION TONIGHT... THE REAL QUESTION FOR TONIGHT IS WHAT TO DO WITH THE CONVECTION WE HAVE IN OUR CURRENT FORECAST? SINCE THE SOUNDING AROUND THE LOWER GREAT LAKES...SFC OBS...SATELLITE IMAGES AND MODEL FORECAST ALL AGREE THAT VERY DRY AIR WILL RULE THE NIGHT OVER SOUTHERN 1/2 OF LOWER MICHIGAN (850 MB TO ABOVE 300 MB)...SEEMS THE RISK OF ANY THUNDERSTORMS IS MINIMAL. CURRENTLY(10/00Z) THERE IS AN OCCLUDED FRONT CROSSING EASTERN LAKE MICHIGAN WITH A WARM FRONT FROM SOUTH BEND TO NORTH OF DAYTON OHIO WITH A QUASI-COLD FRONT FROM THE TRIPLE POINT NEAR SOUTH BEND TO NEAR IRK MO. THERE IS A WAVE ON THE FRONT BTW IRK/STL WHICH HAS AN AREA OF THUNDERSTORMS ON IT. THAT WAVE IS AN AREA OF MUCH HIGHER 850 MB DEW POINTS AND THAT DOES HEAD TOWARD LOWER MICHIGAN TOWARD MORNING. ACTUALLY THE LATEST RUC BRINGS IT IN BETWEEN 06Z AND 09Z SOUTH OF INTERSTATE 94. HOWEVER... THE LOW LEVEL JET (35 TO 45 KNOTS NEAR STL BY 09Z) IS MORE AIMED AT IND THAN ANY PLACE IN MICHIGAN. ALSO THE 850 LI INDEX RISES ABOVE 0C OVER MOST OF OUR CWA BY 03Z AS THE REMAINS OF THAT OCCLUDED FRONT MOVE EAST ACROSS THE STATE. AFTER 06Z WITH THAT NEXT WAVE ON THE FRONT HEADING NORTHEAST... THE 0 TO -2C 850 MB LI DOES NOSE INTO THE INTERSTATE 94 AREA. SO... I WILL UPDATE THE FORECAST TO PARTLY CLOUDY ACROSS THE CWA. I WILL ALSO HAVE A CHANCE OF THUNDERSTORMS LATE TONIGHT IN THE ROW OF COUNTIES NEAR INTERSTATE 94. THE THREAT FOR SEVERE THUNDERSTORMS OVERNIGHT IS MINIMAL. ZONES BY 915 PM. .GRR...NONE. WDM mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1155 AM EDT FRI MAY 9 2003 FOCUS IS COVERAGE/INTENSITY OF SHRA/TS ACROSS UPR GREAT LAKES. OCCLUDED SFC LOW IS CURRENTLY SPINNING OVR CENTRAL MN WITH WARM FRONT JOGGING SE INTO NRN IL. AS TRUE WARM SECTOR IS WELL SOUTH OF UPR MI...MAIN CONCERNS DEALING WITH SHRA AND ELEVATED TS. CURRENT RADAR/LIGHTNING DETECTION NETWORK SHOWS BANDS OF SHRA WITH FEW TS HAVE ROTATED ACROSS CWA THIS MORNING...WITH FAR ERN CWA YET TO GET IN ON ANY SHRA. JUST SOME SCT -SHRA HAVE MADE IT THROUGH CNTRL CWA...BUT OVR WRN TIER ITS A DIFFERENT STORY AS CLUSTER OF SHRA/TS CONTINUE TO AFFECT THESE AREAS DUE TO CONVERGING H85 SPEED MAXES AND LFQ OF UPR JET ROTATING ACROSS UPR GREAT LAKES. LAW ENFORCEMENT EVEN REPORTED SOME PEA SIZED HAIL IN GOGEBIC COUNTY THIS MORNING. GRB 88D SHOWING SCT SHRA/TS EDGING NE OVR NC WI DUE TO INCREASING TEMP ADVECTION AT H85 AND BAND OF DIFFERENTIAL THETA-E FM H8-H7. PRIMARY UPR DIVERGENCE FM LFQ OF UPR JET DOES SHIFT ACROSS LAKE SUPERIOR THIS AFTN SO EXPECT COVERAGE OF SHRA TO REMAIN SCT OVR ALL BUT WRN TIER THROUGH THE EVENING (BETTER H85 CONVERGENCE HANGS ON THROUGH BALANCE OF DAY). AS FOR TS CHANCES THINK ANYWHERE ALONG WI BORDER WILL SEE THE BETTER CHANCE FOR THE AFTN/EVENING AS RUC/ETA SHOWING BETTER DIFFERENTIAL THETA-E AND ELEVATED CAPE (LIFTING FM 750MB) SKIRTING THE WI BORDER. CLUSTERS OF TS ARE ANTICIPATED TO RIDE NE (DUE TO THETA-E ADVECTION) BUT THEN FADE AS BEST MID LEVEL INSTABILITY PROGRESSES MORE E THAN N. BELIEVE PRIMARY HAZARDS WOULD BE BRIEF HVY DOWNPOURS...EXTENSIVE LIGHTNING...AND HAIL UP TO A HALF INCH IN DIAMETER. HIGHLIGHTED THIS IN THE UPDATED HWO. ALL OTHER ELEMENTS OF FORECAST ARE FAIRLY STEADY WITH TEMPS AROUND THE 50F MARK...AND E WINDS 15 TO 25 MPH WITH HIGHER GUSTS TOWARD FAR WRN UPR MI (RESIDING CLOSER TO SFC LOW). JLA EARLIER DISCUSSION FOR LATER PERIODS... LATER TONIGHT INTO SAT...LULL EXPECTED BEFORE NEXT SYSTEM ARRIVES WITH DNVA AND QDIV IN THE WAKE OF THE SHRTWV EXPECTED. WINDS SHOULD DIMINISH ENOUGH TO ALLOW SOME PATCHY FOG TO DEVELOP AS LOW LVL MOISTURE PERSISTS AND PARTIAL CLEARING ALLOWS FOR SOME RADIATIONAL COOLING. SRLY WINDS AND H8 TEMPS FROM 5C-8C SHOULD ALLOW TEMPS TO CLIMB INTO THE 60S...EVEN WITH INCREASING CLOUDS. COOLER AIR WILL REMAIN NEAR LAKE SUPERIOR WHERE ENE WITH LAKE BREEZES PREVAIL. SAT NIGHT INTO SUN...WHILE MDL DIFFERENCES EMERGE WITH PLACEMENT AND STRENGTH OF SFC AND UPR LVL FEATURES...THERE IS AGREEMENT THAT POTENT MID/UPR LVL LOW/SHRTWV AND STRONG SFC LOW WILL MOVE INTO THE WRN LAKES. PREFER UKMET/ETA/GFS/CANADIAN CONSENSUS WITH SFC LO WHICH WOULD BRING SFC LO TO NE WI OR SE UPR MI BY 12Z. STRENGTH OF DYNAMICS...WITH STRONG UPR LVL DIV AND DEEP LYR QVECTOR CONV...JUSTIFY CATEGORICAL POPS. WHILE BEST INSTABILITY EXPECTED CLOSEST TO SFC LOW...TSRA ALSO POSSIBLE GIVEN 00Z ETA/GFS FCST OF SHOWALTER INDICES AOB 0C. KEPT TSRA MENTION EAST EARLY SUN...WHERE POCKET OF INSTABILITY FCST TO LINGER. SUN INTO MON...AS DEEP SFC LOW PULLS AWAY...STRONG CAA WILL BRING FALLING TEMPS FROM WEST TO EAST WITH GUSTY NW WINDS. PLENTY OF MOISTURE SHOULD REMAIN AVBL FOR WRAP-AROUND PCPN AND CONTINUED LIKELY POPS. GFS TREND HAS BEEN TOWARD COLDER AIR MOVING INTO UPR MI LATE SUN NIGHT INTO MON WITH 1000-850 THICKNESS AROUND 1305M ...AND 0C HEIGHT BLO 1K FT AGL (PER 00Z GFS BUFR SNDGS)..SUGGESTING -SHSN POTENTIAL FOR HIGHER TERRAIN AREAS OF WEST/CNTRL UPR MI...AS IN GOING FCST. JLB .MQT...NONE. mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1108 AM EDT FRI MAY 9 2003 STACKED/OCCLUDING SYSTEM LIFTING NORTH ACROSS MN THIS MORNING...WITH WV IMAGERY/UPPER AIR OBS SHOWING A STRONG DRY PUNCH INTO LOWER MI. 12Z SURFACE MAP SHOWS SURFACE LOW OVER SOUTHWEST MN...OCCLUDED/COLD FRONT EXTENDING SOUTH ACROSS EASTERN IA/NORTHERN MO...AND A WARM FRONT ACROSS CENTRAL IL/IN/SOUTHERN OH. 12Z APX SOUNDING ALSO DRY BELOW 600MB WITH DEW POINT DEPRESSIONS AOA 10C. AREA RADAR COMPOSITE SHOWS MCS REMNANTS ZIPPING QUICKLY OFF TO THE EAST...ALREADY OUT OF SOUTHEAST LOWER AND INTO EASTERN OH/WESTERN PA. SO WITHOUT MUCH PRECIP TO ADVECT NORTH COMBINED WITH DRY LOW LAYERS...NORTHERN EDGE OF MCS REMNANT PRECIP HAS PRETTY MUCH FALLEN APART WITH LITTLE MORE THAN SPRINKLES OVER FAR SOUTHERN PORTIONS OF THE AREA. QUESTION FOR THIS AFTERNOON IS WILL WE SEE ANYTHING REDEVELOP...OBSERVED APX SOUNDING SUGGESTS NOT...SO WE'RE GOING TO NEED SOME HELP IF IT WERE TO OCCUR. FOCUS ON PRECIP CHANCES FOR THE AFTERNOON WILL BE ON LOW LEVEL MOISTURE/THETA-E AXIS POKING UP INTO SOUTHWEST LOWER/SOUTHEAST WI. THIS FEATURE WILL BE LIFTING NORTH TODAY INTO CENTRAL LOWER. QG FORCING WILL PERSIST THROUGH THE AFTERNOON AS LOW LEVEL BAROCLINIC ZONE LIFTS NORTH INTO THE AREA...WITH SURFACE OB TRENDS SUPPORTING RUC IDEA OF DEVELOPING A CONVERGENCE AXIS ALONG ROUGHLY A TVC-OSC LINE. THIS FORCING COMBINED WITH MID LEVEL DRYING/CONVECTIVE INSTABILITY WILL HELP STEEPEN LAPSE RATES. DESPITE ALL OF THIS...WILL HAVE A HARD TIME GENERATING A WHOLE LOT OF ELEVATED INSTABILITY EXCEPT PERHAPS LOCALLY. SO PLAN IS TO BACK POPS DOWN TO LOW CHANCE...AND CONFINE THEM ALONG-SOUTH OF M-32 CLOSEST TO ADVANCING LOW LEVEL RIDGE AXIS. CLOUD COVER WILL BE MOST PREVALENT ACROSS EASTERN UPPER AND THE STRAITS...WITH MORE IN AND OUT SUNSHINE ACROSS NORTHERN LOWER. WINDS HAVE BEEN GUSTY THIS MORNING WITH 30-35KT WINDS MIXING DOWN AS THE BOUNDARY LAYER DEPTH INCREASES... THIS SHOULD CONTINUE INTO THE AFTERNOON. UPDATED GRIDS AROUND 1530Z...WITH TEXT TO FOLLOW SHORTLY THEREAFTER. .APX...NONE. $$ JPB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 835 PM CDT FRI MAY 9 2003 SOME GENTLE TWEAKING AND MASSAGING OF THE GRIDS THIS EVENING...BUT GOING FCST HOLDING JUST FINE. NEW GRIDS AND TEXT SHOULD BE OUT BY 02Z. 18Z GFS/ETA AND 21Z RUC SHOWING NOT MUCH CHANGE IN FIRST COUPLE PDS OF FCST. UPR LOW SPINNING AWAY IN NRN MN...WITH SLOWLY BREAKING SC DECK PER LOW LIGHT VIS PIX AND CELLULAR NATURE OF CLDS. WL CONT WITH P/C MENTION IN SRN 1/2 OF CWA TONIGHT. LAST STRONG S/W NOW LIFTING OUT INTO ROCKIES AND NICE BAROCLINIC LEAF SHOWING UP IN SAT PIX. LOW/MID LVL CAA AND DIV-Q REMAINS OVR CWA ALL NIGHT...BUT STRONG THETA-E ADV AND CONV-Q ALREADY ZIPPING INTO SRN NEB BY MORNING. CLOUDS SHOULD ALREADY BE INCREASING OVR SWRN CWA BY 15Z...AS BLOWOFF FROM EXPECTED TSRA DOWN SOUTH LIFTS NORTHEAST. RAPID DEEPENING OF SFC LOW (17MBS IN 24HRS ON 18Z ETA) AS UPR SYSTEMS PHASE OVR WI/MN. LEFT EXIT JET DIVERGENCE...RAPIDLY INCREASING H7-H6 FWF...AND SUBTLE THICKNESS DIFFLUENCE ALL POINT TO ANOTHER NICE STEADY RAIN EVENT FROM KAEL TO KEAU. STREAMS ARE FULL IN WRN WI...SO HYDRO WL NEED TO BE WATCHED TO SEE HOW LONG WAA PRECIP AND THEN DEFORMATION AXIS LINGER SAT NIGHT OVR ERN MN/WRN WI. COULD BE ANOTHER 1" OF RAIN HERE...BUT RIGHT NOW IT LOOKS LIKE THE HEAVIER ACTION WL BE JUST EAST OF CWA. WINDS WL BLOW ON SUN MAKING FOR A RATHER UNPLEASANT DAY FOR MOMS. .MSP...NONE $$ BINAU mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 335 PM CDT FRI MAY 9 2003 ACTIVE WEATHER PATTERN CONTINUES. COLD FRONT HAS BASICALLY BECOME QUASI-STATIONARY ALONG A LINE FROM AROUND QUINCY ILLINOIS TO JUST SOUTH OF KANSAS CITY MISSOURI. CU FIELD SOUTH OF COLD FRONT INDICATING GOOD INSTABILITY...BUT LACK OF BIG TSRA OVER MO ATTM PROBABLY A RESULT OF WEAK CAP AS SHOWN BY ETA BUFR SOUNDINGS. RUC SOUNDINGS ARE INDICATING THAT WE ARE UNCAPPED...BUT WEAK/NON-EXISTENT SURFACE CONVERGENCE ALONG OUR STALLED FRONTAL BOUNDARY IS INHIBITING CONVECTIVE DEVELOPMENT. THIS SHOULDN'T LAST...AND WE ARE EXPECTING CONVECTION TO FIRE ALONG AND SOUTH OF THE FRONT IN THE WARM MOIST AIR ON THE NOSE OF THE LOW LEVEL JET. HPC HAS US OUTLOOKED IN THEIR EXCESSIVE RAINFALL PRODUCT...AND MODEL QPFS ARE IMPRESSIVE TO SAY THE LEAST WITH THE GFS PRINTING OUT 4+ INCHES OF PRECIP OVER CENTRAL PORTIONS OF OUR CWA. FLASH FLOOD GUIDANCE VALUES ARE LOW WITH MOST AREAS HOVERING AROUND THE 1 INCH IN 1 HOUR MARK. HAVE OPTED TO GO WITH A FLOOD WATCH FOR TONIGHT THROUGH NOON TOMORROW TO COVER THIS POTENTIAL HIGH WATER PROBLEM. ADD TO THIS...THE POTENTIAL FOR SEVERE WEATHER. MODEL SOUNDINGS ARE SHOWING SOME 6000+ J/KG OF CAPE EARLY THIS EVENING...QUICKLY FALLING OFF TO A LESS SCARY BUT STILL RESPECTABLE LEVEL OF 3500-4000 J/KG BY MIDNIGHT. THE RUC IS SHOWING BETWEEN 20 AND 30 M/S OF 0-6KM BULK SHEAR WHICH IS WELL INTO SUPERCELL RANGE. WITH THAT IN MIND...AND A NICE BOUNDARY TO SUCK VORTICITY OFF OF...SPC'S MODERATE RISK FOR SEVERE WEATHER TONIGHT LOOKS GOOD. THE FUN CONTINUES ON SATURDAY AS THE COLD FRONT FINALLY GETS MOVING. BOTH THE ETA AND THE GFS ARE FAIRLY CONSISTENT WITH THEIR HANDLING OF THE FROPA. MESOETA SOUNDINGS SHOWING SOME 2000 TO 4000 CAPES DEPENDING ON WHERE YOU'RE STANDING AND BULK SHEAR VECTORS AOA 25 M/S FOR SUPERCELLS. AGAIN...MODERATE RISK FOR SATURDAY 'TILL THE FROPA AROUND MIDNIGHT. THE WEATHER FINALLY CALMS DOWN ON SUNDAY BEHIND THE FRONT. A COOL HIGH PRESSURE SYSTEM BUILDS IN AND HANGS IN INTO NEXT WEEK. EXTENDED...QUIET WEATHER CONTINUES INTO TUESDAY NEXT WEEK AS SURFACE RIDGE FINALLY SLIDES SOUTH OF THE AREA INTO WESTERN TENNESSEE AND EASTERN ARKANSAS. THE NEXT MAJOR SHORT WAVE TO AFFECT THE AREA STARTS DEEPENING AT 500 MB OVER THE DAKOTAS BETWEEN 00Z AND 12Z WEDNESDAY MORNING. ASSOCIATED SURFACE SYSTEM DEVELOPS OVER SOUTHERN NEBRASKA AT THAT TIME AND BEGINS DRAWING MOISTURE BACK NORTHWARD INTO THE MID-MISSISSIPPI VALLEY REGION. KEPT CHANCE TSRA IN FOR BOTH WEDNESDAY AND THURSDAY...AND WENT DRY FOR FRIDAY AS IT LOOKS LIKE THE SYSTEM SHOULD BE CLEAR OF THE AREA BY THEN. FOLLOWED ENSEMBLE MOS/HPC GUIDANCE CLOSELY FOR TEMPS THROUGH PERIOD. .STL...FLOOD WATCH ALONG AND NORTH OF A LINE FROM OWENSVILLE MO TO NASHVILLE IL. CARNEY mo AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 805 PM MDT FRI MAY 9 2003 WATER VAPOR IMAGERY SHOWS UPPER LOW SPINNING OVER NE ND THIS EVENING WITH ANOTHER UPPER LOW OVER UTAH. MOISTURE PLUME STREAMING NORTH ALONG THE FRONT RANGE INTO ERN WY. COMPARING 18Z ETA TO 00Z UNR SOUNDING SHOWS ETA OVERESTIMATED THE INSTABILITY OVER OUR CWA AGAIN TODAY...SUPPPORTED BY LACK OF LIGHTNING IN OR NEAR OUR CWA. 01Z RUC SEEMS TO HAVE INITIALIZED WELL. SFC LOW CURRENTLY OVER NW MN WITH TROUGH EXTENDING WESTWARD INTO NW SD. KUDX 88D INDICATES AN AREA OF LIGHT RAIN HAS DEVELOPED ALONG THE LEADING EDGE OF THE SFC TROUGH AND IS CURRENTLY DECREASING IN COVERAGE AND INTENSITY AS DIURNAL HEATING DIMINISHES AND UPPER DIVERGENCE DECREASES DUE TO JET STREAK TO OUR SOUTHEAST MOVING OFF INTO SE MN. EXPECT TO SEE PRECIP INCREASE IN COVERAGE AND INTENSITY AGAIN AFTER MIDNIGHT AS CURVED JET STREAK ROUNDS THE BASE OF THE LONGWAVE TROUGH TO THE WEST AND UPPER DIVERGENCE INCREASES AGAIN AND 500MB VORT MAX ROTATING UP FROM THE SOUTH INTERACTS WITH VORT MAX ROTATING SOUTHWARD AROUND UPPER LOW OVER NE ND. 850MB TEMPS AROUND +2C AND 700MB AROUND -7C BY 12Z STILL POINT TO A CHANCE OF SNOWFLAKES OVER THE BLKHLS TOWARD MORNING. .UNR...NONE. $$ GR sd SOUTH PLAINS AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LUBBOCK TX 417 PM CDT FRI MAY 9 2003 .DAY ONE... DRY LINE HAS PUSHED NORTH AND FAIRLY HARD UP AGAINST CAPROCK AT THIS TIME...MUCH FURTHER WEST THAN EARLIER MODEL RUNS...BUT FAIRLY CLOSE TO CURRENT RUC MODEL. SHORTWAVE LIFTING ACROSS WEST CENTRAL TEXAS WITH JET ON ORDER OF 100 KTS WILL BE FOCUS FOR ACTIVITY NEXT FEW HOURS BRUSHING OUR SOUTHEAST COUNTIES. TORNADO WATCH 320 WILL BE IN EFFECT UNTIL 900 PM THIS EVENING. WE REMAIN SOMEWHAT CONCERNED ABOUT MOISTURE INCREASE AND WILL THUS KEEP MENTION OF SEVERE THUNDERSTORMS OVER ALL COUNTIES OFF THE CAPROCK. EVEN THOUGH SOUTHWESTERLY COMPONENT WILL BE INCREASING TONIGHT AS VIGOROUS LOW HEADS THROUGH CENTRAL ROCKIES... SUSPECT THE DRY LINE WILL NOT BE AS AGGRESSIVE TO THE EAST AS THE GFS AND ESPECIALLY ETA. THEREFORE KEPT SLIGHT CHANCE OF THUNDERSTORMS AFTER MIDNIGHT FOR EXTREME SOUTHEAST ZONES. A BIT STRONGER FLOW SATURDAY...WITH AN INCREASE IN WESTERLY COMPONENT...WILL DRY OUT LOW LEVELS COMPLETELY. ENOUGH GRADIENT TO REMAIN CONCERNED ABOUT WIND SPEEDS FOR FIRE WEATHER ISSUES AND WILL RETAIN FIRE WEATHER WATCH. WIND SPEEDS AT THIS POINT LOOK STRONGEST LATE SATURDAY MORNING AND THEN SHOULD DIE OFF SLOWLY REMAINDER OF THE DAY. EXPECT SPEEDS ATO REMAIN BELOW ADVISORY LEVELS AND MAY ALSO NOT BE QUITE STRONG ENOUGH FOR A BIG BLOWING DUST EVENT. .DAYS TWO THROUGH SEVEN... COLD FRONT FOLLOWING SATURDAY SHORTWAVE SHOULD DROP THROUGH AREA EARLY SATURDAY EVENING...CLOSER TO ETA TIMING. DRY AND CONFLUENT UPPER LEVEL WESTERLY FLOW AS RIDGE BUILDS ACROSS THE AREA...SO EXPECT SUNDAY TO BE COOL AND QUIET. SURFACE HIGH PRESSURE RIDGE SHIFTING OFF TO THE EAST SUNDAY NIGHT WILL INCREASE LOW LEVEL SOUTHEAST COMPONENT AND PULL MUCH HIGHER DEWPOINTS BACK INTO THE AREA. GFS STILL INCREASES DEEP MOISTURE IN H850-500 MB LAYER NORTHWARD THROUGH TRANS PECOS LATE MONDAY NIGHT...BUT SEEMS LESS AGGRESSIVE THAN PREVIOUS MODEL RUN. MID LEVEL OVERRUNNING THE COOL SURFACE RIDGE COULD GIN UP A FEW THUNDERSTORMS...BUT MAY ALSO CREATE TOO STRONG OF A CAP. FOR NOW WILL HOLD ON TO SLIGHT CHANCE OF THUNDERSTORMS FOR MONDAY. GFS HINTS AT ANOTHER WEAKER WAVE PASSING JUST NORTH ON TUESDAY LEADING TO LEE SIDE SURFACE PRESSURE FALLS AND INCREASING WARM SOUTHERLY COMPONENT. MOISTURE SHOULD BE PLENTY EMBEDDED INTO AREA BY THEN AND ENOUGH TO MAINTAIN CHANCE OF THUNDERSTORMS. PROBLEMS IN MEDIUM RANGE MODELS DEVELOP WEDNESDAY AND BEYOND WITH THE GFS MUCH SLOWER MOVING THE NEXT PACIFIC CUTOFF LOW ON SHORE AND THROUGH THE SOUTHWEST. GFS SOLUTION WOULD MAINTAIN RIDGE OVER OR JUST WEST OF AREA AND ALLOW A STRONG SHORTWAVE TO DIG SOUTHEAST THROUGH THE PLAINS STATES WITH ATTENDANT COLD FRONT ON OR AROUND THURSDAY. BUT PREFERENCE IS FOR THE MUCH MORE PROGRESSIVE ECMWF WHICH MOVES LOW ABOUT A DAY AHEAD OF THE GFS INTO OUR AREA AROUND THURSDAY OF NEXT WEEK AND NEVER ALLOWS ABOVE MENTIONED PLAINS SHORTWAVE TO FORM. WILL OPT TO MAINTAIN CHANCE OF THUNDERSTORMS FOR WEDNESDAY IN ADVANCE OF THIS LOW...THEN DRY IT OUT WITH INCREASING WINDS FOR THURSDAY INTO FRIDAY. ALSO KEEPING TEMPERATURES MUCH WARMER THAN GFS FOR LATE NEXT WEEK. LOTS COULD CHANGE FOR NEXT WEEK AND WITH HIGHER MOISTURE LEVELS THAN WE HAVE SEEN FOR A WHILE...STAY TUNED. MCQUEEN/05 FCSTID = 05 FRIONA 53 82 44 76 / 00 00 00 00 TULIA 56 83 46 75 / 00 00 00 00 LUBBOCK 56 86 49 77 / 00 00 00 00 BROWNFIELD 57 87 51 79 / 00 00 00 00 CHILDRESS 58 86 50 72 / 20 00 00 00 ASPERMONT 61 92 54 74 / 20 00 00 00 .LUB...RED FLAG WARNING UNTIL 700 PM TXZ021>037-039>042. FIRE WEATHER WATCH FOR SATURDAY. TORNADO WATCH 320 TILL 900 PM TXZ038-044. $$ tx SOUTH PLAINS AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE LUBBOCK TX 142 PM CDT FRI MAY 9 2003 HAVE UPDATED FORECAST TO SHOW BETTER CHANCE OF THUNDERSTORMS ALONG THE EASTERN EDGE OF THE CAPROCK AND OVER THE ROLLING PLAINS AND SOUTHEAST PANHANDLE THIS AFTERNOON AND TONIGHT. WINDS IN EASTERN COUNTIES HAVE BECOME SOUTHEASTERLY AND DEW POINTS ARE EXPECTED TO RISE THROUGH THE AFTERNOON INTO THE EVENING. THE LATEST RUC MODEL SHOWS THE DRYLINE CONTINUING TO MOVE NW TO NEAR THE EDGE OF THE CAPROCK BY LATE AFTERNOON. WITH INCREASING MOISTURE AND INSTABILITY...SOME OF THE STORMS MAY BECOME SEVERE. LIPE .LUB...RED FLAG WARNING TODAY FOR TXZ021>037-039>042. FIRE WEATHER WATCH FOR SATURDAY. $$ tx WEST CENTRAL TEXAS FORECAST DISCUSSION...CORRECTION NATIONAL WEATHER SERVICE SAN ANGELO TX 1101 AM CDT FRI MAY 9 2003 FEW SEVERE STORMS THIS MORNING AS WARM AIR LIFTED OVER DRYLINE...MOST ACTIVITY HAS SHIFTED NORTH OF OUR AREA WHERE SUNNIER SKIES WILL HELP CONTINUE T-STORM DEVELOPMENT. SATELLITE IMAGERY SHOWS DRYLINE JUST EAST OF FORT STOCKTON...TO NEAR BIG SPRING OR JUST WEST OF OUR COUNTY WARNING AREA. DRYLINE SHOULD MOVE SLIGHT WEST IN RESPONSE TO LOW DEVELOPING TO OUR WEST...SO THE SLIGHT CHANCE OF AFTERNOON STORMS WILL PERSIST THIS AFTERNOON. CLOUDS OVER AREA...WILL REDUCE HI TEMPS A BIT..SO WILL TWEAK TEMPS DOWN SLIGHTLY FOR THIS AFTERNOON. ...................... 430 AM CDT FRI MAY 9 2003 .CURRENT...SURFACE OBSERVATIONS AND SATELLITE IMAGERY DEPICT DRYLINE ROUGHLY ALONG A LINE FROM RANKIN AND SAN ANGELO...TO ABILENE AND THROCKMORTON. DRYLINE HAS MOVED VERY LITTLE SO FAR TONIGHT... PRIMARILY DUE TO VEERING WIND PROFILES IN WAKE OF POTENT UPPER LOW NOW LIFTING INTO SOUTHERN MINNESOTA. BUT WITH THE STRONG UPPER LOW OVER CENTRAL NEVADA DIGGING TOWARD THE FOUR CORNERS...EXPECT THE FLOW TO BACK THROUGH THE MORNING HOURS. THIS IN TURN WILL PUSH THE DRYLINE INTO MY WESTERN COUNTIES (SEE ISC GRIDS FOR DETAILS). .TODAY-TONIGHT...DRYLINE WILL BEGIN PUSHING EAST AGAIN DURING THE AFTERNOON HOURS. RUC40 AND MESOETA ADVERTISING 3000 J/KG CAPES EAST OF THE DRYLINE THROUGH 06Z SATURDAY. CIN VALUES ALSO DROP TO LESS THAN 20 J/KG...BUT DATA DECEIVING. MID LEVEL TEMPERATURES LOOK AWFUL WARM SOUTH HALF TODAY AND TONIGHT WHICH WILL LIMIT THUNDER POTENTIAL...IF NOT SQUASH IT ALL TOGETHER. CAP NOT AS STRONG OVER THE BIG COUNTRY...SO THUNDER POTENTIAL GREATER. LOW LEVEL JET COULD ACT TO SUSTAIN ISOLATED THUNDERSTORMS INTO THE OVERNIGHT HOURS. BULK OF DYNAMICS ASSOCIATED WITH FOUR CORNERS UPPER LOW TO REMAIN WELL NORTH OF AREA. .SATURDAY-SATURDAY NIGHT...PERHAPS A FEW THUNDERSTORMS ALONG THE DRYLINE FAR EAST SATURDAY MORNING. WEST WINDS THEN BRING IN DRIER AIR SATURDAY AFTERNOON. WEAK COLD FRONT DROPS THROUGH THE FORECAST AREA SATURDAY NIGHT WITH LITTLE FANFARE SINCE MOISTURE STARVED. COMFORTABLE SLEEPING WEATHER SATURDAY NIGHT AS DRIER AIR ALLOWS READINGS TO DIP INTO THE 50S. .SUNDAY-MONDAY...COLD FRONT EXPECTED TO STALL ACROSS SOUTH TEXAS EARLY SUNDAY. IT THEN BEGINS TO LIFT SLOWLY NORTH (WARM FRONT)... PERHAPS REACHING A SAN ANGELO TO SAN SABA LINE BY 00Z TUESDAY. STRONG SOUTHEAST FLOW TO THROW COPIOUS GULF MOISTURE OVER SAID BOUNDARY...WHILE A SERIES OF UPPER LEVEL DISTURBANCES TRAVERSES THE FORECAST AREA IN FAST ZONAL FLOW. OVERRUNNING SCENARIO SHOULD BRING ISOLATED THUNDERSTORMS TO THE EDWARDS PLATEAU AND THE NORTHWEST HILL COUNTRY SUNDAY AFTERNOON. FOR SUNDAY NIGHT AND MONDAY...SCATTERED THUNDERSTORMS A GOOD BET ACROSS THE ENTIRE FORECAST AREA...WHICH IS GOOD NEWS FOR THIS RAIN STARVED REGION. .TUESDAY-THURSDAY...ACTIVE NORTHWEST FLOW ALOFT AND MEANDERING FRONTAL BOUNDARY PROMISES TO BRING MORE RAIN FOR TUESDAY AND WEDNESDAY. HIGH PRESSURE AT THE SURFACE AND ALOFT SHOULD DRY THINGS OUT BY THURSDAY. CCF... ABI 096/070/088/053 2200 SJT 098/069/092/055 1100 JCT 096/074/088/060 1100 .SJT...NONE. $$ 17 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 300 PM CDT FRI MAY 9 2003 .TONIGHT AND SATURDAY MAIN FORECAST CONCERN CLOUDS/TEMPERATURES/WINDS/THUNDERSTORMS. DATA ANALYSIS SHOWING TWO SURFACE LOWS OF CONCERN IN THE SHORT RANGE. THE FIRST IS NORTH OF KMSP AND THE SECOND IS NEARING THE OK/TX PANHANDLE. IN THE IMMEDIATE AREA...MODERATE PRESSURE GRADIENT AND SOME MIXING HAVE CAUSED WINDS TO INCREASE ACROSS THE FORECAST AREA TODAY. THIS WILL BE TEMPORARY...AS GRADIENT SHOULD RELAX OVERNIGHT AS THE NORTHERN SURFACE CONTINUES MOVING NORTH. CLOUDS HAVE DECREASED OVER THE SOUTHERN COUNTIES IN THE FORECAST AREA. THIS IS DEPICTED BY THE RUC/ETC MOISTURE FORECASTS. MODELS BEHAVING RATHER INTERESTING THIS PERIOD. AS THE SOUTHERN LOW MOVES EAST TONIGHT...CONVECTION DEVELOPS ALONG ITS WARM FRONT WHICH EXTENDS FROM THE LOW ACROSS MISSOURI INTO SOUTHERN ILLINOIS. THIS ACTIVITY SHOULD CAUSE CIRRUS BLOWOFF TO BE PUSHED INTO THE REGION ON THE UPPER LEVEL WINDS. BOTH THE ETA/GFS AGREE WITH THIS SOLUTION. THE MODEL DIFFERENCES REALLY BEGIN ON SATURDAY. AS THE SOUTHERN SURFACE LOW MOVES NORTHEAST...A STRONG AREA OF FORCING /MOST NOTABLE IN THE 850-700 MB LAYER/ MOVES NORTHEAST INTO THE FORECAST AREA. THIS BEGINS ABOUT MID-MORNING SATURDAY ACROSS THE NORTHEAST IOWA ZONES...OVERSPREADING THE FORECAST AREA BY AFTERNOON SATURDAY. THE GFS SHOWS A GOOD AMOUNT OF CONVECTION WITH THIS FORCING...WHILE THE ETA DOES NOT. CONSISTENCY AND PERFORMANCE FAVORS THE GFS HERE...AND THIS SOLUTION WILL CONTINUED TO BE FAVORED. TRIMMED TEMPERATURES A FEW DEGREES ON SATURDAY. 850 MB TEMPERATURES CHANGED VERY LITTLE AND WITH THE CLOUDS AND INCREASED CHANCE OF PRECIPITATION DURING MAX HEATING...JUST THIS THE HIGHS WILL BE MORE REFLECTIVE OF THE GFS MOS VERSUS THE OTHERS. KRC .SATURDAY NIGHT THROUGH FRIDAY MAIN CONCERN DAYS 2 THROUGH 7 ARE WINDS AND CHANCES OF PRECIPITATION SUNDAY INTO MONDAY...AND CHANCES OF PRECIPITATION WEDNESDAY. BOTH ETA AND GFS CONTINUE TO EJECT UPPER LEVEL/SFC LOW INTO THE GREAT LAKES REGION BY 12Z SUNDAY...WITH ETA SLOWER OF THE TWO. WILL LEAN MORE TOWARDS GFS SOLUTION...AS ETA HAS TRENDED TOWARD THE GFS SOLUTION IN MOVING SFC LOW QUICKER INTO EASTERN WISCONSIN SUNDAY. NOT LOOKING AT ISSUING ANY TYPE OF WATCH OR ADVISORY ASSOCIATED WITH POSSIBLE WIND EVENT. THIS IS DUE TO THE FACT THAT BOTH MODELS SHIFT STRONGEST GRADIENT INTO EASTERN HALF OF WISCONSIN...THOUGH WILL HIGHLIGHT WINDY WORDING IN FORECAST AND HAZARDOUS WEATHER OUTLOOK. ANY SEVERE THUNDERSTORM THREAT SATURDAY NIGHT WILL BE SOUTH AND EAST OF COUNTY WARNING AREA...WHERE BETTER INSTABILITY WILL BE LOCATED SOUTH OF WARM FRONT OVER NORTHERN ILLINOIS. 850MB MOISTURE TRANSPORT CONTINUES TO INDICATE THE HEAVIEST RAIN WILL BE ALONG OR JUST SOUTH OF THE FRONT. REGION WILL HAVE ENOUGH UPPER LEVEL DYNAMICS AND LIFT TO SUPPORT THUNDERSTORMS ACROSS THE COUNTY WARNING AREA. WILL CONTINUE WITH SHOWERS AND THUNDERSTORMS LIKELY SATURDAY NIGHT AND SHIFTING WEST TO EAST SUNDAY MORNING ACROSS COUNTY WARNING AREA. FOR SUNDAY...THE ETA CONTINUES TO SUPPORT A STRONG WIND EVENT...WHILE THE GFS HAS SHIFTED MOST OF THE FAVORABLE FIELDS TO THE EAST. SINCE THE GFS CONTINUES TO BE FAVORED AT THIS TIME...WILL NOT ISSUE HEADLINES AS WAS STATED ABOVE. THE ETA SHOWS STRONG LOW LEVEL LAPSE RATES / 7C/KM / AND A PRESSURE GRADIENT THAT COULD PRODUCE STRONG WINDS. EVEN THROUGH IT LOOKS MORE LIKE THE GFS...IT STILL PRODUCES A MIXED LAYER WIND OF 40+ KNOTS OVER MUCH OF THE FORECAST IN THE BUFKIT DATA. AS A RESULT...WILL CONTINUE TO HIGHLIGHT AND MENTION IN THE HAZARDOUS WEATHER OUTLOOK. SFC RIDGE BUILDS INTO REGION ON MONDAY...THIS WILL ALLOW CLOUDS AND PRECIPITATION TO DISSIPATE WEST TO EAST ACROSS COUNTY WARNING AREA LATE SUNDAY NIGHT AND INTO MONDAY. WILL CONTINUE TO HOLD SLIGHT CHANCES OF SHOWERS ACROSS NORTHERN AND EASTERN ZONES MONDAY...AS SYSTEM LIFTS EAST NORTHEAST INTO SOUTHERN CANADA. 00Z FRIDAY GFS DEVELOPS SHORT WAVE OVER SOUTHERN ALBERTA AND DROPS IT SOUTH INTO NORTHERN PLAINS WEDNESDAY MORNING. THIS IS QUITE DIFFERENT FROM THE 12Z THURSDAY ECMWF AND PREVIOUS RUNS OF THE GFS. THE 12Z ECMWF CONTINUES TO BUILD UPPER LEVEL RIDGE INTO MANITOBA AND SASKATCHEWAN. WILL LEAN MORE TOWARD THE ECMWF THROUGH PERIOD...AS THE ECMWF HAS BEEN MORE CONSISTENT ON BUILDING UPPER LEVEL RIDGE INTO THE UPPER MIDWEST WEDNESDAY AND INTO THURSDAY. WILL CONTINUE TO KEEP DRY AND SEASONABLE TEMPERATURES IN FORECAST TUESDAY THROUGH FRIDAY. DTJ .LSE...WATCHES/WARNINGS/ADVISORIES...NONE. $$ KRC wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 215 AM CDT SAT MAY 10 2003 FORECAST CONCERNS ARE PRECIP TRENDS TODAY AND SVR POTENTIAL. NEAR TERM...CONVECTION HAS DEVELOPED AND SPREAD NORTHWARD INTO SOUTHEAST NEBRASKA. DISTANCE SPEED TOOL INDICATES PRECIP INTO SW IA PRIOR TO ZONE ISSUANCE. WITH ELEVATED INSTABILITY NOSING INTO SRN IA...EARLY MORNING STORMS WL BEAR WATCHING. THE SHORT RANGE MODELS ARE IN FAIRLY GOOD AGREEMENT WITH THE EVOLUTION OF THE SYSTEM THROUGH THE AREA TODAY AS WELL AS PRECIP COVERAGE AND AMOUNTS. THE GFS BRINGS THE SFC LOW INTO FAR SE IA AROUND 00Z...THE META 1-2 HRS SLOWER...AND THE 20KM RUC FASTER AROUND 21Z. NGM IS FARTHEST WEST WITH THE LOW...THE GFS FARTHEST EAST. IF THE NGM VERIFIES...THE OTTUMWA AREA HAS A TORNADO THREAT LATE AFTERNOON/EARLY EVENING...OTHERWISE THE THREAT WOULD REMAIN TO THE SOUTH AND EAST OF THE FORECAST AREA. THIS SYSTEM HAS IMPRESSIVE MID AND UPPER JET DYNAMICS...AND SUBSTANTIAL MOISTURE IN SRN IA. BUFKIT SOUNDINGS INDICATE AFTERNOON CAPE AROUND 3000 J/KG WITH SRH WELL OVER 300 AT OTTUMWA. WL MENTION ISOLD TORNADO THREAT INVOF OTTUMWA IN HWO...BUT BELIEVE MAIN THREAT WILL BE SUPERCELLS WITH LARGE HAIL AND POSSIBLY DAMAGING WIND ALONG AND SE OF A MONTEZUMA TO CORYDON LINE. AFTER SVR THREAT INTO THE EARLY EVENING...SFC LOW WILL RACE TO THE NORTHEAST AND DEEPEN RAPIDLY...WITH DEF ZONE RAINS SPREADING INTO THE NORTHEAST COUNTIES. MODEL QPF FOR TODAY/TONIGHT IS SIMILAR WITH A RANGE FROM A QUARTER UP TO ABOUT 0.60 INCHES WITH THE HIGHEST OVER THE NORTHEAST. HPC HAS WIDESPREAD AMOUNTS OVER 1/2 INCH OVER FA. PWATS OF 1-1.5 INCHES PROGGED DURING THE AFTERNOON AND EVENING IN THE SOUTHEAST. SOME LOCATIONS COULD SEE TOTAL RAINFALL AROUND AN INCH BY SUNDAY MORNING WITH ISOLD HIGHER...CERTAINLY ENOUGH TO CAUSE SOME MORE RIVER FLOODING PROBLEMS...BUT LIKELY NOT ENOUGH FOR FLASH FLOOD CONCERNS. WL MENTION SHOWERS IN THE NORTH SUNDAY...BUT WOULDN'T BE SURPRISED TO SEE SOME FARTHER SOUTH AS VORT LOBE ROTATES THROUGH. FOR TEMPERATURES...WL GO WITH BLEND OF WARMER MET AND COOLER MAV GUIDANCE TODAY. GUIDANCE IS VERY SIMILAR TONIGHT INTO MONDAY. EXTENDED PERIOD (TUE-FRI): MEDIUM RANGE MODELS PROVIDE A WIDE VARIETY OF SOLUTIONS THIS PERIOD AND CONFIDENCE IS LOW. LATEST GFS BRINGS H5 LOW THROUGH REGION IN NW FLOW AND GENERATES PRECIP ACRS CWA TUE AND WED. CANADIAN HAS PRECIP TUES WITH WED DRY. ENSEMBLE PRECIP PROBS SUPPORT SOME PRECIP BOTH DAYS. FOR NOW WL INTRODUCE POPS TUESDAY WEST AND ACRS ENTIRE FA WED AND DAY SHIFT TAKE ANOTHER LOOK. OTHERWISE...NO CHANGES WITH POPS IN THE SOUTH THURSDAY AND WARMING BY THE END OF THE PERIOD. .DSM...NONE KINNEY ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPRINGFIELD MO 315 AM CDT SAT MAY 10 2003 ...MESOSCALE CONVECTIVE DISCUSSION... CONVECTION CURRENTLY FORMING CLOSE TO THE WARM FRONTAL BOUNDARY. PROFILERS INDICATING 40-50KT LLJ NOSING INTO SOUTH CENTRAL KANSAS. RUC ANALYSIS IS SHOWING THAT THE INSTABILITY AXIS LIES ACROSS THE WARM FRONT. THE COMBINATION OF DEEP LOW-LEVEL MOISTURE...GOOD SHEAR PROFILES...AND THE FRONTAL BOUNDARY ACTING AS A FOCUSING MECHANISM SHOULD KEEP THE THREAT OF TORNADIC SUPERCELLS GOING FOR THE REST OF THE OVERNIGHT HOURS. WILL CLOSELY MONITOR THE KANSAS ACTIVITY AS IT APPROACHES THE MISSOURI BORDER. .SGF... MO...FLOOD WATCH TODAY...055>058-067>069. KS...NONE. GAEDE mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPRINGFIELD MO 130 AM CDT SAT MAY 10 2003 ...MESOSCALE CONVECTIVE DISCUSSION... EXTREMELY LONG LIVED TORNADIC SUPERCELL CONTINUES TO HOLD ITS OWN...AND GOING THROUGH CYCLES AS IT WORKS ITS WAY UP THE I44 CORRIDOR. IT SEEMS VERY UNLIKELY THAT THIS STORM WOULD BE ABLE TO MAINTAIN ITSELF INTO SOUTHWEST MISSOURI...HOWEVER 4 HOURS AGO WE WOULDN'T HAVE EXPECTED IT TO LAST THIS LONG SO ALL BETS ARE OFF. SHEAR PROFILES VERY FAVORABLE FOR SUPERCELLS ASSUMING THAT IT WOULD BE SURFACED BASED. STRONG CAP EVIDENT ON OUR 0Z SOUNDING HAS HELPED PREVENT MUCH CONVECTION FROM GETTING GOING IN OUR CWA THUS FAR. SOME SLIGHTLY MARGINALLY SEVERE CONVECTION GOT GOING EARLY THIS EVENING HAS BASICALLY DIED OFF. SGF 88D SHOWS WHAT APPEARS TO BE GRAVITY WAVES EMANATING FROM THE SUPERCELL WITH ADDITIONAL CONVECTION CURRENTLY FIRING UP IN THAT "ZONE" OF GRAVITY WAVES. GIVEN HOW CLOSE THE CELL IS GETTING...WE HAVE GOTTEN NERVOUS ENOUGH TO SEND UP A 7Z SOUNDING TO TRY AND GET A BETTER FEEL FOR HOW THE LOW LEVEL THERMAL FIELDS HAVE CHANGED AND TO HOPEFULLY ASCERTAIN HOW STRONG THE CAP IS IN OUR AREA. IZZI MORNING FORECAST DISCUSSION... FORECAST CONCERNS: CONVECTION TODAY. SEVERE POTENTIAL...AND CHANCES OF PRECIPITATION BY MIDWEEK. ALL EYES CONTINUE TO BE ON SUPERCELL OVER NORTHEAST OKLAHOMA WHICH WILL BE ONE OF THE MAIN CONCERNS THIS MORNING. OTHER CONCERN WILL BE CONVECTIVE COMPLEX THAT SHOULD DEVELOP ALONG AND NORTH OF SURFACE BOUNDARY...MAINLY NORTH OF FORECAST AREA THIS MORNING. HAVE DECIDED TO LEAVE FLOOD WATCH FOR AREAS ALREADY IN AFFECT TODAY...HOWEVER BELIEVE HEAVIEST RAINFALL SHOULD HOLD OFF JUST TO THE NORTH. LOOKING AT SEVERE WEATHER PARAMETER THIS MORNING...BELIEVE SUPERCELL SHOULD BEGIN TO DISSIPATE...OR AT THIS BECOME MORE DISORGANIZED AS IT TRACKS OFF TO THE NORTHEAST INTO NORTHWEST ARKANSAS/SOUTHWEST MISSOURI. WILL DECIDE BEFORE ZONE ISSUANCE IF SEVERE WORDING THIS MORNING FOR AREAS SOUTH OF I-44. ALTHOUGH ALL MODELS ARE HAVING PROBLEMS WITH CONVECTIVE COMPLEX IN OKLAHOMA...THE MESOETA IS DEPICTING A GOOD CORRELATION WITH THUNDERSTORMS DEVELOPING ALONG AND NORTH OF SURFACE BOUNDARY DURING THE NEXT FEW HOURS. VIS/FOG AND REGIONAL RADAR IS DEPICTING THIS SCENARIO...WHICH WILL PROVIDE A GOOD FORECAST BASIS THIS MORNING. THEREFORE WILL CONTINUE LIKELY POPS AROUND THE LAKE OF THE OZARKS WITH CHANCE POPS EVERYWHERE ELSE THIS MORNING. THINGS CONTINUE TO LOOK GOOD FOR SEVERE WEATHER THIS AFTERNOON AS THE MAIN COLD FRONT MOVES THROUGH THE AREA. BUFKIT PARAMETERS AND RUC INDICATE WEAKENING CAP OVER SOUTHEAST KANSAS AND WEST CENTRAL MISSOURI BY 21Z JUST AHEAD OF COLD FRONT. MID LEVEL TEMPS/MOISTURE AND WIND FIELDS INDICATE A SQUALL LINE EVENT AS THUNDERSTORMS DEVELOP ALONG COLD FRONT OVER WESTERN MISSOURI BY MID/LATE AFTERNOON. ALTHOUGH MAIN UPPER LEVEL FORCING SHOULD BE NORTH OF FORECAST AREA...BELIEVE A GOOD CHANCE OF THUNDERSTORMS SPREADING ACROSS THE FORECAST AREA THROUGH THE LATE AFTERNOON AND EARLY EVENING TIME PERIOD. LEFT A SLIGHTLY CHANCE IN SOUTH CENTRAL MISSOURI AFTER MIDNIGHT DUE TO TIMING AFFECTS OF FRONTAL BOUNDARY. THIS SHOULD BE THE LAST OF THE SEVERE WEATHER SCENARIOS AS STABLE/DRY HIGH PRESSURE BUILDS IN FOR SUNDAY/MONDAY. LATEST GFS RUN CONTINUES AN UPPER LEVEL STORM SYSTEM MOVING IN BY TUESDAY AS NORTHWEST FLOW DEVELOPS. WILL CONTINUE THE SAME FORECAST IN THE EXTENDED...HOWEVER I HAVE MODIFIED TUESDAY FORECAST FOR EVENING SHOWERS AND THUNDERSTORMS. .SGF... MO...FLOOD WATCH TODAY...055>058-067>069. KS...NONE. JLT mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 232 AM EDT SAT MAY 10 2003 HI PRESS RIDGE TO BUILD ACRS THE FA TODAY AND OUT TO THE EAST OF THE FA TONITE. STORM SYS TO MOVE UP INTO THE GREAT LKS REGION TONITE AND ON SUN...AND THEN TO THE NORTH OF THE FA ON MON THRU TUE. THIS SYSTEM/S ASSOCIATED CF TO MOVE ACRS THE FA BY LATE ON SUN AND SUN NITE. 00-02Z 20KM "DEVELOPMENT" RUC SHOWS TEMPS TO GET UP INTO THE 60S TO NEAR 70F TODAY WITH WINDS BECOMING NORTHERLY AT 5-20 KTS. T1MAX TEMPS ARE IN THE M60S TODAY. FEW TWEAKS TO FIRST PERIOD TEMPS/WINDS BASED ON THIS DATA AND CURRENT MESONET OBS. LOW-LVLS TO BE DRY ACRS THE FA TODAY...AND RUC SHOWS MOSUNNY SKIES ACRS THE FA TODAY. IR SAT PIX/BUFCAN SHOW SOME CLDS/SPRINKLES MOVING DOWN ACRS ONT ATTM. H85 NEUTRAL ADVECTION TO TAKE PLACE ACRS THE FA TODAY...THEN WK WAA FOR TONITE AND GOOD WAA ON SUN. WK CAA TO DEVELOP ACRS THE FA ON SUN NITE AND CONT INTO MON/MON NITE. H85 THETA-E RIDGE TO MOVE ACRS THE FA FROM THE WEST ON SUN NITE. LOW-LVL LAPSE RATES TO BE HI ACRS THE FA TODAY AND ON MON AFTERNOON/MON NITE. LOW-LVL MSTR ADVECTION TO TAKE PLACE ACRS THE FA LATE TONITE AND ON SUN. LOW-LVL MSTR TO INCREASE ACRS THE FA FROM THE WEST ON SUN AND LINGER ACRS THE FA INTO TUE. SOME MID-LVL MSTR TO START TO AFFECT THE FA BY LATE ON SUN AND INTO SUN NITE...WITH GOOD MID-LVL MSTR ACRS THE FA ON MON INTO TUE. PW VALUES ACRS THE FA LOOK TO BE AROUND AN INCH ON SUN AND THEN AOB 0.75" ON SUN NITE THRU MON NITE. JUST A FEW CLDS EXPECTED ACRS THE FA TODAY AND TONITE. BEST CHC FOR ANY PCPN APPEARS TO BE ACRS THE WRN/CENTRAL ZONES BY LATE ON SUN AND HAVE INDICATED THIS THINKING IN THIS FCST PACKAGE. 00Z ETA SHOWS CAPES TO BE AOB 1000 J/KG TO THE WEST OF THE FA BY LATE ON SUN...SO A STRAY TS MAY SNEAK INTO THE ST LAW VLY BY LATE IN THE DAY ON SUN... BUT WILL LEAVE OUT OF FCST FOR NOW AND SEE IF THIS TREND HOLDS. FRONTAL AND POST-FRONTAL PCPN A GOOD BET ON SUN NITE THRU TUE WITH UPR LOW SPINNING NEAR THE FA IN THIS TIME-FRAME. NO CHANGES TO THE GOING ZFP BEYOND TUE FOR NOW. WRK ZONES OUT UNDER ALBWRKCWF. FINAL ZFP BY 4 AM. .BTV...NONE. MURRAY vt