EAST CENTRAL FLORIDA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 825 PM EDT SUN AUG 3 2003 .DISCUSSION...DAYTIME CONVECTION HAS DIMINISHED ACROSS AREA. LARGE PATCHES OF RAIN LINGERED AND WERE MOVING NORTH NORTHEAST AS ATLANTIC RIDGE WAS NUDGING SOUTH. NOTICED A WEAK CYCLONIC SHEAR AXIS ALOFT IN RUC ANALYSIS/WATER VAPOR PUSHING NORTH ACROSS THE EASTERN GULF. THIS MIGHT HELP TO DISSIPATE RAIN AREAS SO NOT EXPECTING POPS TO LINGER TOO LONG INTO THE EVENING. REST OF THE FORECAST SPEAKS FOR ITSELF WITH MOIST AIR MASS IN PLACE LEADING TO ABOVE NORMAL SHOWER/STORM COVERAGE FOR MOST OF THE WORK WEEK. .MARINE...MAIN STORY HAS BEEN THE ARRIVAL OF SOME EASTERLY SWELL DURING THE LATE AFTERNOON. SEA HEIGHTS AT THE BUOYS HAVE BEEN AROUND 5 FEET. WILL BUMP UP SEAS OVERNIGHT TO REFLECT THIS. FETCH AREA SHOULD NUDGE A LITTLE SOUTH WITH SURFACE RIDGE TOMORROW ...SO EXPECT THE SWELL WILL DECREASE A LITTLE...BUT NOT DISAPPEAR COMPLETELY. WILL HAVE TO WATCH FOR RIP CURRENTS WITH THIS SEA HEIGHT ANOMALY. .MLB WATCHES/WARNINGS/ADVISORIES...NONE. $$ LASCODY fl SOUTHEAST MICHIGAN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1018 PM EDT SUN AUG 3 2003 CONVECTIVE ACTIVITY IS BEGINNING TO WANE ACROSS THE FORECAST AREA. BROKEN LINE OF STORMS WILL CONTINUE TO PUSH EAST INTO LESS FAVORABLE CONDITIONS AS THE BOUNDARY INSTABILTY IS RAPDILY BEING DEPLETED. GIVEN THE EASTWARD PROGRESSION OF THE COLD AIR ALOFT ASSOCIATED THE UPPER LEVEL CICULATION OVER WISCONSIN, ANTICIPATE THAT ISOLATED ACTIVITY WILL CONTINUE THROUGH THE OVERNIGHT HOURS. OTHERWISE, CLOUD DEBRIS TO THE WEST IS RAPIDLY DISSIPATING, SO EXPECT SKIES TO BECOME PARTLY CLOUDY ONCE AGAIN AFTER THE CONVECTION DIES OFF. WILL TOSS IN PATCHY FOG ONCE AGAIN FOR THE OVERNIGHT, GIVEN THAT MOST AREAS SAW RAINFALL DURING THE DAY. .DTX...NONE. MANN -----AFTERNOON DISCUSSION FOLLOWS----- ...PCPN CHCS REMAIN MAIN CHALLENGE AS UPPER LOW EDGE INTO/OVER CWA... NOT MUCH NEW TO SAY IN ANALYZING THIS SITUATION AS UPPER LOW CONTINUES ITS SLOW TREK TOWARD LOWER MICHIGAN. DECENT WAVE IN DEEP MOISTURE PLUME IS ENHANCING SHRAS/TSRAS ACROSS MAINLY THE EASTERN CWA EARLY THIS AFTN AND THIS WILL CONTINUE INTO THIS EVENING...LIKELY FILLING IN JUST A BIT MORE AND PULLING EVER SO SLIGHTLY MORE TO THE NW AROUND CIRCULATION OF UPPER LOW. WILL HAVE TO DELINIATE JUST WHERE SCT CONVECTION CAN BE TERMED NUMEROUS. WILDCARD COULD BE LAKE BREEZE CONVECTION OUT WEST...WHICH COULD CONCEIVABLY PROGRESS INTO CWA LATER TONIGHT W/ HELP OF 20KT NE FLOW THRU ATMOS. IN FACT...15Z RUC SUGGESTS THIS IDEA. ANYWAY...WILL EVALUATE TRENDS OF BOTH CURRENT CONVECTION OVER CWA AND THAT IN SW LOWER THIS AFTN...AND TWEEK GRIDS ACCORDINGLY AT ISSUANCE. THEREAFTER...UPPER LOW MOVES OVERHEAD BY TOMR AFTN/EVENING. WILL KEEP LIKELY POPS IN THIS TIMEFRAME GIVEN THE COLD CORE WILL BE OVERHEAD AND MOISTURE WILL STILL BE DECENT ACROSS CWA. IF LOOKING UPSTREAM TODAY IS ANY INDICATION...THIS SHOULD VERIFY...AS CONVECTION WITHIN COLD CORE NOW OVER WI THIS AFTN IS QUITE ACTIVE. ONLY CHANGES TO FCST WILL BASICALLY BE TO TRY TO WORD PRECIP AS AFTN AND EVENING SHRAS/TSRA ONCE UPPER LOW GETS JUST NE OF CWA BY TUE AND DEEPER LLVL MOISTURE IS FORCED TO THE EAST. WILL AFTN/EVE POPS IN THRU THU AFTN...AT WHICH TIME UPPER SYSTEM MAY HAVE OPENED UP & EDGED FAR ENUF INTO SE CANADA TO KEEP FCST DRY...SAVE AN ISOLATED AFTN RW-. THIS IS NOT CLEAR CUT...HWVR...AS REINFORCING SHORTWAVE IS PROGGED TO DROP DOWN BACKSIDE OF THIS SYSTEM HEADING INTO THE WEEKEND... WHICH MAY HELP TO INCREASE PCPN CHCS AGAIN. FOR NOW...WILL ASSUME GFS IS TOO STRONG WITH THIS SYSTEM...AND LEAVE FRI-SUN DRY. WILL KEEP TEMPS DOWN...THOUGH...AS OVERALL TROF SHOULD REMAIN FAIRLY AMPLIFIED WITH A CONTINUED SUPPLY OF ENERGY DIGGING INTO ITS BASE. NO REASON TO ARGUE WITH THIS SOLUTION...AS THE MODEL CONSENSUS FOR QUITE SOME TIME AS SUGGESTED THIS UPPER LOW/TROF WOULD BE WITH US FOR AT LEAST THE BETTER PART OF 2 WEEKS...AND WE STILL HAVE A SOLID WEEK TO GO. THAT SAID...HIGHS TEMPERATURES WILL AVERAGE IN THE UPPER 70S TO 80 THIS UPCOMING WEEK...WITH LOWS IN THE EDGING BACK FROM THE L/M 60S TONIGHT...CLOSER TO 60 OR A BIT LOWER IN BEHIND SYSTEM AS COOLER AIR ADVECTS INTO LOWER MICHIGAN...AND MORE IMPORTANTLY...WE TEND TO LOOSE AFTN/EVENING CLOUDINESS FROM CONVECTION QUICKER. .DTX...NONE. $$ GURNEY 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 420 PM EDT SUN AUG 3 2003 MAIN FCST CONCERNS ARE SHRA/TSRA TRENDS/COVERAGE. WV IMAGERY AND RUC ANALYSIS INDICATED PERSISTENT H5 LOW OVER NRN WI. ONE SHRTWV WAS MOVING NORTH THROUGH SW LWR MI. AT THE SFC...LOW PRES WAS LOCATED NEAR KORD WHILE SFC RDG EXTENDED FROM NW ONTARIO TOWARD THE ERN DAKOTAS. OTHERWISE...AS IN RECENT DAYS AREAS OF SLOW MOVING TSRA WITH LCLY HEAVY RAIN HAVE DEVELOPED NEAR THE UPR LOW CENTER SUPPORTED BY MUCAPES (FROM 925-850 MB) TO NEAR 1000 J/KG. RADAR ESTIMATES AND SFC REPORTS INDICATED RAINFALL AMOUNTS OF 3-4 INCHES BTWN KIMT AND IRON RIVER FROM MID MORNING INTO EARLY AFTERNOON. AXIS OF HEAVIER PCPN HAD SHIFTED A BIT FARTHER NORTH WITH BANDS OF SHRA/TSRA CONTINUING TO SPIRAL TO THE WNW AROUND THE MID/UPR LVL LOW WITH TSRA DEVELOPING INTO ERN UPR MI. MDLS WERE IN REASONABLE AGREEMENT IN HANDLING CONTINUED SLOW DRIFT OF THE MID LVL LO TO THE SE. WITH HPC COMMS PROBLEMS...DETAILS FROM ETA NOT AVBL WITH MM5 SUBSTITUTED. GFS WAS ALSO DELAYED. SO...WAS HESITANT TO MAKE SIGNIFICANT CHANGES FROM GOING FCST WHICH IS MAINLY ON TRACK. TONIGHT INTO MON...PER RADAR AND SATELLITE TRENDS...EXPECT NMRS SHRA/TSRA TO CONTINUE OVER SOUTH AND E UPR MI THIS EVENING WITH MORE SCT COVERAGE FARTHER TO THE NORTH AND WEST. ENOUGH WESTWARD MOTION WITH CELLS AND MOVEMENT OF BANDS MINIMIZING CELL TRAINING SHOULD KEEP LCL RAINFALL AMOUNTS IN THE 1-2 INCH RANGE. PULSING CELLS IN VERY WEAK SHEAR ENVIRONMENT MAY ALSO PRODUCE SOME SMALL HAIL WITH THE STRONGER STORMS. WITH WEAK NERLY FLOW AND ABUNDANT LOW LVL MOISTURE REMAINING...SOME DENSE FOG IS AGAIN LIKELY TONIGHT...ESPECIALLY FOR AREAS FAVORED BY UPSLOPE NE FLOW SUCH AS THE HIGHER TERRAIN OF NORTH CNTRL UPR MI. MDLS SUGGEST THAT AS THE ELONGATED LOW WOBBLES INTO LWR MI BEST QVECTOR CONV...INFLUENCE OF WEAK SHRTWVS AND DEEP MOISTURE WILL SLIDE INTO THE EAST HLF OF UPR MI. DIURNAL ENHANCEMENT OF PCPN AGAIN EXPECTED BY MON AFTERNOON WITH BEST COVERAGE OVER THE E...WHERE LIKELY POPS RETAINED. WEAK QDIV AND MI/UPR LVL CONFLUENT FLOW CLOSER TO SFC RDG SHOULD KEEP WRN UPR MI DRY. MON NIGHT INTO WED...MID/UPR LVL CONTINUES SLOW PROGRESSION TO THE EAST INTO SE ONTARIO BY 00Z/WED. EXPECT BEST PCPN CHANCES AGAIN OVER THE EAST. ISOLD/SCT DIURNAL SHRA/TSRA ALSO APPEAR POSSIBLE OVER INLAND PORTIONS OF CNTRL UPR MI WHERE MM5 FCST SBCAPES AOA NEAR 500-1000 J/KG. SIMILAR SITUATION EXPECTED WED WITH GFS FCST SHOWING ENOUGH INSTABILITY FOR SCT/ISOLD INLAND SHRA AND A FEW TSRA. THU-SUN...MDLS WERE IN REASONABLE AGREEMENT WITH OVERALL SCENARIO WITH EPAC TROF...DOWNSTREAM RDG FROM THE SRN ROCKIES TO THE NRN PLAINS AND A TROF FROM THE LWR LAKES TO THE SE CONUS. THIS WILL LEAVE THE WRN LAKES IN A MAINLY DRY NNW MID/UPR LVL FLOW PATTERN WITH LITTLE MOISTURE INFLOW INTO THE REGION. MID LVL TEMPS (H5 TEMP NEAR -12C PER GFS AND ECMWF) AND 700-500 LAPSE RATES AROUND 6C/KM MIGHT SUPPORT ISOLD DIURNAL CONVECTION BUT SINCE EXPECT LESS THAN 20 POPS...WL NOT ADD MENTION TO WX GRIDS. STABILIZING NRLY FLOW OFF OF LK SUPERIOR WOULD FURTHER MINIMIZE PCPN CHANCE OVER NRN UPR MI. BY SUN...GFS SUGGESTS WAA PATTERN MAY DEVELOP AS NRN PLAINS RDG BUILDS TOWARD THE AREA. WHILE ECMWF/UKMET DEPICTION OF SLOWER PROGRESSION LOOKS MORE REASONABLE GIVEN HIGH AMPLITUDE FLOW...CANNOT RULE OUT POSSIBILITY OF CONVECTION INTO WRN UPR MI AS MOISTURE INCREASES AND SHRTWVS SLIDE TOWARD THE AREA FROM THE NW. .MQT...NONE. JLB mi SOUTHEAST MICHIGAN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 245 PM EDT SUN AUG 3 2003 ...PCPN CHCS REMAIN MAIN CHALLENGE AS UPPER LOW EDGE INTO/OVER CWA... NOT MUCH NEW TO SAY IN ANALYZING THIS SITUATION AS UPPER LOW CONTINUES ITS SLOW TREK TOWARD LOWER MICHIGAN. DECENT WAVE IN DEEP MOISTURE PLUME IS ENHANCING SHRAS/TSRAS ACROSS MAINLY THE EASTERN CWA EARLY THIS AFTN AND THIS WILL CONTINUE INTO THIS EVENING...LIKELY FILLING IN JUST A BIT MORE AND PULLING EVER SO SLIGHTLY MORE TO THE NW AROUND CIRCULATION OF UPPER LOW. WILL HAVE TO DELINIATE JUST WHERE SCT CONVECTION CAN BE TERMED NUMEROUS. WILDCARD COULD BE LAKE BREEZE CONVECTION OUT WEST... WHICH COULD CONCEIVABLY PROGRESS INTO CWA LATER TONIGHT W/ HELP OF 20KT NE FLOW THRU ATMOS. IN FACT...15Z RUC SUGGESTS THIS IDEA. ANYWAY...WILL EVALUATE TRENDS OF BOTH CURRENT CONVECTION OVER CWA AND THAT IN SW LOWER THIS AFTN...AND TWEEK GRIDS ACCORDINGLY AT ISSUANCE. THEREAFTER...UPPER LOW MOVES OVERHEAD BY TOMR AFTN/EVENING. WILL KEEP LIKELY POPS IN THIS TIMEFRAME GIVEN THE COLD CORE WILL BE OVERHEAD AND MOISTURE WILL STILL BE DECENT ACROSS CWA. IF LOOKING UPSTREAM TODAY IS ANY INDICATION...THIS SHOULD VERIFY...AS CONVECTION WITHIN COLD CORE NOW OVER WI THIS AFTN IS QUITE ACTIVE. ONLY CHANGES TO FCST WILL BASICALLY BE TO TRY TO WORD PRECIP AS AFTN AND EVENING SHRAS/TSRA ONCE UPPER LOW GETS JUST NE OF CWA BY TUE AND DEEPER LLVL MOISTURE IS FORCED TO THE EAST. WILL AFTN/EVE POPS IN THRU THU AFTN...AT WHICH TIME UPPER SYSTEM MAY HAVE OPENED UP & EDGED FAR ENUF INTO SE CANADA TO KEEP FCST DRY...SAVE AN ISOLATED AFTN RW-. THIS IS NOT CLEAR CUT...HWVR...AS REINFORCING SHORTWAVE IS PROGGED TO DROP DOWN BACKSIDE OF THIS SYSTEM HEADING INTO THE WEEKEND... WHICH MAY HELP TO INCREASE PCPN CHCS AGAIN. FOR NOW...WILL ASSUME GFS IS TOO STRONG WITH THIS SYSTEM...AND LEAVE FRI-SUN DRY. WILL KEEP TEMPS DOWN...THOUGH...AS OVERALL TROF SHOULD REMAIN FAIRLY AMPLIFIED WITH A CONTINUED SUPPLY OF ENERGY DIGGING INTO ITS BASE. NO REASON TO ARGUE WITH THIS SOLUTION...AS THE MODEL CONSENSUS FOR QUITE SOME TIME AS SUGGESTED THIS UPPER LOW/TROF WOULD BE WITH US FOR AT LEAST THE BETTER PART OF 2 WEEKS...AND WE STILL HAVE A SOLID WEEK TO GO. THAT SAID...HIGHS TEMPERATURES WILL AVERAGE IN THE UPPER 70S TO 80 THIS UPCOMING WEEK...WITH LOWS IN THE EDGING BACK FROM THE L/M 60S TONIGHT...CLOSER TO 60 OR A BIT LOWER IN BEHIND SYSTEM AS COOLER AIR ADVECTS INTO LOWER MICHIGAN...AND MORE IMPORTANTLY...WE TEND TO LOOSE AFTN/EVENING CLOUDINESS FROM CONVECTION QUICKER. .DTX...NONE. $$ GURNEY EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1100 AM EDT SUN AUG 03 2003 ...WILL LOWER POP THIS AFTERNOON TO SCATTERED... THE PRIMARY PROBLEM IS WHAT TO DO WITH THE POP THIS AFTERNOON. CURRENTLY THERE IS AN SIX TENTHS AREA OF SHOWERS AND SCATTERED THUNDERSTORMS THAT EXTEND FROM THE WESTERN UPPER PENINSULA OF MICHIGAN ACROSS NORTHERN LOWER MICHIGAN...THEN SOUTH SOUTHEAST TOWARD THE NORTHWEST OHIO. THIS AREA IS LIFTING SLOWLY NORTH AND IS ASSOCIATED WITH BOTH THE JET EXIT REGION LIFT (UPPER MI/NRN LWR) AND A SHORTWAVE THAT SHOWS UP WELL ON THE WATER VAPOR LOOPS FROM WI INTO LOWER MICHIGAN. THERE IS THE CLASSIC DRY SLOT POKING INTO SOUTHWEST LOWER MICHIGAN. ALSO... THERE IS A QUASI-COLD FRONT (DRY LINE MORE SO) FROM THE SURFACE LOW NEAR MKE TO NEAR STL. MEANWHILE THERE WAS ALMOST NO ECHOS IN THE GRR CWA (OK...THERE ARE SOME OVER OUR N AND ERN CWA). SO...WHAT WILL HAPPEN? MY GUESS IS THE PRIMARY WARM ADVECTION LIFT (1000/925/850 WARM ADVECTION AND 700 MB ISENTROPIC LIFT) PLUS THE DEEP MOISTURE CONVERGENCE (1000/850 THTE CONVERGENCE AND 850 DEW POINT AXIS) ARE MOSTLY ALREADY EAST OF THE GRR CWA. EVEN SO...THERE IS A GOOD DEAL OF HIGH AND MID CLOUDS ASSOCIATED WITH WARM ADVECTION PATTERN TO OUR EAST THAT IS STILL OVER MOST OF THE CWA. THAT WILL LIMIT THE INSTABILITY SOME. THE SW CORNER OF THE CWA HAS THE BEST CHANCE OF DECENT THUNDERSTORMS SINCE THAT "COLD FRONT OF SORTS" WILL BE MOVING SLOWLY INTO THE CWA THERE AND THAT AREA WILL HAVE THE GREATEST AMOUNT OF SUNSHINE. RUC SOUNDINGS SUGGEST 2500 J/KG POSSIBLE SOUTH AND WEST OF GRR BY 21Z. EVEN SO... THE ETA AND RUC SUGGEST SW LWR IS IN A AREA OF UPPER CONVERGENCE (NOT GOOD FOR LIFT). THE REST OF THE AREA WILL LIKELY NOT DESTABILIZE ENOUGH AND THE PRECIPITATION WITH THE WARM CONVEYOR BELT WILL BE EAST OF THE CWA. THUS I WILL LOWER THE CHANCE OF PRECIPITATION TO "SCT" FOR ALL AREAS THIS AFTERNOON. TONIGHT THE CONVECTION SHOULD END TOTALLY BY MIDNIGHT OR SO (SURFACE HEATING GONE AND LITTLE DYNAMIC REASON TO KEEP IT GOING). THERE IS A SMALL RISK OF ISOLATED SEVERE THUNDERSTORMS OVER THE SW PART OF THE CWA THIS AFTERNOON DUE TO THE CAPES NEAR 2500 J/K AND FREEZING LEVEL NEAR 11,500 FT. SO HAIL WOULD BE THE MOST LIKELY TYPE OF HAZARD. OF COURSE WIND IS POSSIBLE TOO BE THE WIND PROFILE SURE DOES NOT SUPPORT ANY MAJOR SEVERE THREAT BY ITSELF DUE TO THE LACK OF VERTICAL SHEAR AND ANY WIND OVER 25 KNOTS BELOW 20,000 FT. ZONES BY 1115 AM. .GRR...NONE. WDM $$ mi SOUTHEAST MICHIGAN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1100 AM EDT SUN AUG 3 2003 THE WATER VAPOR LOOP SHOWS A SHORT WAVE TROUGH EXTENDING FROM SW LOWER MI TO NW OHIO. THE WAVE IS PIVOTING AROUND THE PERSISTENT UPPER LOW OVER NORTHERN WISCONSIN. THE LATEST RUC ACTUALLY LIFTS THIS SHORT WAVE DUE NORTH THIS AFTERNOON AND EVENING. THE 12Z UPPER AIR PLOTS SHOWED AMPLE DEEP MOISTURE OVER THE EASTERN OHIO VALLEY AND EASTERN GREAT LAKES REGION. THIS DEEPER MOISTURE WILL PUSH NORTH INTO EXTREME EASTERN LOWER MI THIS AFTERNOON. THUS...I EXPECT THE CURRENT AREA OF PRECIPITATION OVER NORTHWEST OHIO WILL CONTINUE TO ADVANCE NORTHWARD DURING THE AFTERNOON. LIKELY POPS THIS AFTERNOON AND EVENING IN THE CURRENT FORECAST THUS LOOKS GOOD. AMPLE CLOUDS AND SHOWER ACTIVITY SHOULD INCREASE BOUNDARY LAYER STABILITY...LIMITING THE POTENTIAL FOR SEVERE WEATHER THIS AFTERNOON/EVENING. WITH STEEP MID LEVEL LAPSE RATES ASSOCIATED WITH THE 500MB COLD POOL JUST WEST OF THE CWA AND WITH THE WATER VAPOR LOOP SHOWING A NICE MID LEVEL DRY PUNCH ACCOMPANYING THE MID LEVEL TROUGH...THERE WILL BE ENOUGH ELEVATED INSTABILITY TO CONTINUE TO WARRANT MENTION OF THUNDER THIS AFTERNOON/EVENING. THE ONLY UPDATES TO THE GRIDS WILL BE TO RAISE POPS A LITTLE IN THE EAST GIVEN THE DEEPER MOISTURE AND TO LOWER AFTERNOON TEMPS A COUPLE DEGREES GIVEN THE AMOUNT OF CLOUD COVER AND EXPECTED PRECIP OVER THE REGION. CONSIDINE ...3 AM DISCUSSION FOLLOWS... NO LARGE SCALE CHANGES TO CURRENT FORECAST SEEN...AS BROAD LOW PRESSURE SURFACE AND ALOFT SLOWLY AMBLES EAST ACROSS THE GREAT LAKES REGION NEXT FEW DAYS. AT 500 MB...SLOWLY PROGRESSIVE CLOSED LOW SHOWN BY MODELS TO PIVOT OCCASIONAL SHORTWAVE ENERGY ACROSS THE FORECAST AREA THROUGH MONDAY. GFS AND CANADIAN GLOBAL FAVORED IN BEING MORE PROGRESSIVE WITH THE UPPER LOW...MOVING IT OUT AND TENDING TO OPEN IT UP SOONER THAN ETA...THOUGH STILL RETAINING CYCLONIC FLOW OVERHEAD THROUGH MID WEEK WITH MORE ENERGY SWINGING IN FROM THE BACKSIDE. AT THE SURFACE...LOW PRESSURE RATHER BROAD AND DIFFUSE WHILE CRAWLING IN A GENERALLY EASTWARD DIRECTION. WITH LOW TO MID LEVEL THETA E ADVECTION CONTINUING THIS MORNING AND SETTING UP MODEST THETA E RIDGE OVER MOST OF FORECAST AREA BY THIS AFTERNOON...WILL FOLLOW CURRENT RADAR TRENDS AND CALL FOR ISOLATED SHOWERS AND THUNDERSTORMS THIS MORNING EXCEPT SCATTERED IN SOUTHEASTERN COUNTIES...THEN LIKELY MENTION THIS AFTERNOON. FLUX OF BETTER/DEEPER MOISTURE TODAY...THEN...FOLLOWED BY PRETTY GOOD MOISTURE CONTINUING THEREAFTER THROUGH EARLY PART OF WEEK. OMEGA LIFT IN THE LOW TO MID LEVELS SHOWN BY MODEL CONSENSUS GIVING GLANCING BLOW TO SOUTHERN COUNTIES THIS MORNING...BUT MODEST OVER MOST OF AREA THIS AFTERNOON INTO THIS EVENING AND OCCASIONALLY MODEST THROUGH MONDAY. 850 TO 500 MB QVECTOR CONVERGENCE VERY MODEST TODAY...WITH GFS/NGM CONTINUING SLIGHT TONIGHT AND MONDAY...AND MODELS ALSO OFFERING OCCASIONALLY MODEST SURFACE CONVERGENCE THROUGH MONDAY. SOME MODEST 250 MB DIVERGENCE/850 MB CONVERGENCE COUPLING SETTING UP BY THIS AFTERNOON...IN VICINITY OF LEFT EXIT REGION OF UPPER JET. WITH RELATIVELY WEAK WIND FIELDS AHEAD OF APPROACHING LOW SYSTEM...LAKE BREEZES LIKELY TO GENERATE THIS AFTERNOON AND AGAIN MONDAY MAINLY OFF OF LAKE HURON TO HELP FOCUS/KICK OFF CONVECTION... WITH OUTFLOW BOUNDARIES ALSO FORMING FOCUSING MECHANISMS. GIVEN THE CURRENT HIGHER CLOUDS PREVALENT OVER MUCH OF AREA AND EXPECTED TODAY...AND WITH THIN SPOTS/BREAKS EXPECTED TO FILL LARGELY IN THIS AFTERNOON WITH LOWER CLOUDS GIVEN HEALTHY CUMULUS SCHEME...CLOUDS SHOULD PREVAIL TODAY. THESE CLOUDS MAY TEND TO INHIBIT CONVECTION A BIT...BUT THERE EXISTS ENOUGH FORCING FOR SHOWERS/THUNDER. K INDICES WILL BE HIGHER THAN YESTERDAY...INTO LOWER 30S AND A LITTLE LESS AGAIN MONDAY. SURFACE LIFTED INDICES EXPECTED DOWN TO MINUS 3 TO MINUS 5 MOST OF THE AREA BY EARLY AFTERNOON... SIMILAR MONDAY...WITH LITTLE OR NO CONVECTIVE INHIBITION...THOUGH CAPES QUITE MODEST BOTH DAYS OF GENERALLY BELOW 1000 JOULES EXPECTED. GIVEN RATHER MODEST 0 TO 6 KM SHEAR AND WEAK 0 TO 3 KM SHEAR...ORGANIZED STRONG CONVECTION NOT VERY LIKELY...BUT 850 TO 700 MB LAPSE RATES AS GREAT AS 7 C/KM QUITE IMPRESSIVE. WET BULB ZERO VALUES AROUND 10K FEET WOULD MAKE LARGE HAIL POSSIBILITY LESS THAN IDEAL AS WELL. WILL CONTINUE THE FORECAST HIGHS PLUS OR MINUS 80 TODAY...SUPPORTED BY TRAJECTORY FORECAST USING SATURDAY MAXIMUM TEMPERATURES...THEN LITTLE CHANGE ALSO THEREAFTER...IN QUITE GOOD AGREEMENT WITH GFS MOS TEMPERATURES...MET TEMPERATURES APPEAR TOO LOW. .DTX...NONE. $$ DWD EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION...UPDATED FOR MESOSCALE DICUSSION NATIONAL WEATHER SERVICE BUFFALO NY 335 PM EDT SUN AUG 3 2003 ...UPDATED FOR MESOSCALE DISCUSSION... THE LACK OF CLOUD COVER EAST OF ROCHESTER AND DANSVILLE HAS RESULTED IN PLENTY OF DESTABILIZATION FOR THE AIRMASS OVER THE FINGER LAKES AND EAST OF LAKE ONTARIO. 19Z RUC BASED LAPS DISPLAYS PROJECT CAPE VALUES OF 2000 TO 2500 J/KG FOR THE FINGER LAKES REGION WITH VALUES IN EXCESS OF 3000 J/KG EAST OF SYR. MEANWHILE LI'S HAVE DROPPED TO -6 IN THE SAME AREA. VIS SAT AND REGIONAL DOPPLER COMPOSITE LOOPS ARE SHOWING TRWS POPPING UP IN THIS VERY UNSTABLE AIRMASS. PW'S OF 1.75" AND MINIMAL LL BACKING WINDS ARE ENOUGH CAUSE FOR CONCERN. RAIN LOADED DOWNBURSTS ARE PROBABLY THE BIGGEST THREATS ALONG WITH LOCALIZED POOR DRAINAGE FLOODING. WILL HAVE TO BE WATCHED CLOSELY. TRAINING NORTH TO SOUTH ORIENTED RW/TRW OVER MCKEAN COUNTY WILL HAVE TO BE WATCHED FOR POSSIBLE FLOOD PROBLEMS IN CATT AND ALLEG COUNTIES OF OUR SRN TIER. ...BULK OF PREVIOUS AFD LEFT BELOW... SITES EAST OF THE GENESEE VALLEY ARE ENJOYING A BEAUTIFUL DAY... ALBEIT A LITTLE HUMID...WHILE THE FAR WESTERN COUNTIES ARE FEELING THE INFLUENCES OF A WEAK UPPER LEVEL IMPULSE. THE RESULT...WIDESPREAD SHOWERS AND A FEW TRWS WITH MORE TO COME INTO THE EVENING. OUR PERSISTENT CLOSED LOW THAT HAS BEEN STATIONARY OVER EXTREME SOUTHWEST ONTARIO FOR THE PAST FEW DAYS IS FINALLY ON THE MOVE. WV IMAGERY CONFIRMS MODEL GUIDANCE THAT THE FEATURE WILL START TO MOVE SOUTHEAST TONIGHT. THE FEATURE WILL WORK ITS WAY ACROSS WISCONSIN AND LOWER LICHIGAN BY TUESDAY AFTERNOON...THEN CROSS SOUTHERNMOST ONTARIO TUESDAY NIGHT AND WEDNESDAY. THE ABOVE SCENARIO WILL MEAN MUCH OF THE SAME KIND OF WEATHER ACROSS THE REGION WITH DAILY CHANCES FOR RW/TRW. WEAK IMPULSES/SHORT WAVES ROTATING AROUND THE CLOSED UPPER LEVEL LOW HAVE BEEN...AND WILL CONTINUE TO BE THE FOCUSING MECHANISM FOR THE PCPN. YESTERDAYS MODEL GUIDANCE DID UNUSUALLY WELL WITH THE CURRENT FEATURE PRODUCING RAIN...BUT AM NOT PUTTING A LOT OF FAITH INTO TIMING OF UPCOMING IMPULSES. THIS IS ESPECIALLY THE CASE GIVEN THE PROBLEMS BEING EXPERIENCED THIS AFTERNOON WITH LACK OF SOME MODEL DATA (IE. NO AVN). IN ANY CASE...REGIONAL RADARS ARE LOADED UP FROM BUFFALO TO PIT AND WEST VIRGINIA AS ONE SUCH IMPULSE IS TEAMING UP SOME UPPER LEVEL DYNAMMICS TO PRODUCE WIDESPREAD RW/TRW. THIS ACTIVITY WILL CONTINUE TO TRACK ACROSS THE WRN COUNTIES LATE THIS AFTERNOON...AND WILL SHIFT EAST ACROSS THE GENESEE VALLEY AND FINGER LAKES AS THE EVENING PROGRESSES. MEANWHILE...PLENTY OF SUN OVER THE EASTERN LK ONTARIO COUNTIES AND EASTERN FINGER LAKES HAS DESTABILIZED THE AIRMASS TO THE POINT WHERE LAPS PROJECTS CAPES TO BE IN THE ORDER OF 1500-2000 J/KG. THIS AREA WILL HAVE TO BE WATCHED LATE THIS AFTERNOON FOR PULSE ACTIVITY. TONIGHT...THE BEFORE MENTIONED IMPULSE WILL LIFT NORTH OF THE AREA. PCPN SHOULD END FROM SOUTH TO NORTH AS THE NIGHT PROGRESSES. DO NOT EXPECT MUCH OF ANYTHING BETWEEN MIDNIGHT TONIGHT AND NOON MONDAY... ALTHOUGH AVAILABLE MODEL GUIDANCE IS A BLEND OF PATCHED ETA/MM5 AND SOLUTIONS LOOK SUSPECT. AM RELYING MORE ON THE GOOD OL' CANADIAN GEM AT THIS POINT. GEM SUGGESTS THAT THE UPPER LEVEL STORM IS FURTHER NORTH FOR MONDAY THAN LIMITED U.S. GUIDANCE SUGGESTS. AM NOT BITTING ON THAT IDEA...BUT WILL KEEP TAME POPS (CHC) IN PLACE GIVEN LACK OF ANY SIGNIFICANT SHORTWAVES SHOWN BY THE MODELS. THIS ALSO FOLLOWS OUR CONTINUITY...WHICH WILL BE WEIGHED MORE THAN USUAL IN THE LONGER RANGE. EARLIER LONG RANGE MODELS INDICATED THAT THE UPPER LEVEL SYSTEM WOULD FINALLY OPEN UP INTO A LONG WAVE TROF BY MID-LATE WEEK. WHILE THIS WILL NOT TOTALLY BRING US OUT OF THE WOODS (PCPN-WISE)...IT WILL CERTAINLY LOWER THE POPS. .BUF...NONE. $$ RSH ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 1008 AM EDT SUN AUG 3 2003 ONSHORE FLOW CONTINUES TO BRING THE TROPICAL MOISTURE ONSHORE. THIS WILL HELP PROPAGATE SEA BREEZE INLAND TODAY AND CURRENT RADAR SHOWING SHOWERS ALREADY DEVELOPING ALONG THE COAST WHERE LAPS IS DEPICTING CAPE BETWEEN 1500 AND 2000. EXPECT MOISTURE INFLOW WITH LOW NORTH OF THE BAHAMAS. LOOKING AT THE 12Z RUC SHOWING DECENT UVV MOTION AT 700 MB. SO WILL CONTINUE WITH THE CURRENT PRECIPITATION FORECAST AND NO UPDATE IS PLANNED IN PUBLIC FORECAST. MARINE FORECAST...WILL INITIALIZE FOR THE CURRENT CONDITIONS NO MAJOR CHANGES PLANNED. FCSTID = 7 PRELIMINARY NUMBERS... ILM 87 75 88 74 / 50 40 40 30 FLO 89 73 89 72 / 50 50 50 40 LBT 88 72 88 71 / 50 50 50 40 MYR 85 76 86 75 / 50 40 40 30 .ILM... .NC...NONE. .SC...NONE. HAWKINS ---------------------PREVIOUS DISCUSSION-------------------------- WESTERN ATLANTIC RIDGE AND INLAND UPPER TROF WILL CONTINUE TO DUKE IT OUT DURING THIS FCST PERIOD. THIS PLACES THE ILM CWA UNDER THE BATTLE FIELD WITH CONVECTION EXPECTED EVERY DAY. WESTERN ATLANTIC RIDGE THE WINNER OF THE BATTLE TODAY THRU LATE MON. THIS MORNINGS NOCTURNAL CONVECTION TO BE REPLACED BY DIURNAL MESOSCALE SFC TRIGGERED CONVECTION LATER THIS MORNING AND INTO THIS EVENING. BEST FORCING UPSTAIRS REMAINS WELL INLAND FROM THE FA. POPS OF 50 PERCENT ALL LOCATIONS SHOULD DO. MODELS KEEP TROPICAL FEATURE WELL EAST OF THE FA THIS AFTERNOON...BUT CONTINUES TO AID CONVECTION OVER THE ADJACENT WATERS. 1 LAST NITE OF NOCTURNAL ATLANTIC WATERS CONVECTION AS SFC-7H FLOW CONDUCIVE ENUF TO KEEP POPS IN JUST FOR CSTL CNTYS AFTER MIDNIGHT. ELONGATED 5H IMPULSE APPROACHES THE FA FROM THE WEST ON MON AS UPPER TROF STARTS TO SLOWLY PROGRESS EAST. THIS WILL AID THE DIURNALLY DRIVEN CONVECTION MON INTO MON NITE. WILL GO ATLEAST 40-50 POPS. FOR MON NITE THRU WED...INFLUENCES OF THE UPPER INLAND TROF MORE PREVALENT...AS FLOW ALOFT INVOLVES A WESTERLY COMPONENT. THIS WILL SHUT OFF THE ATLANTIC WATERS NOCTURNAL CONVECTION MACHINE DURING THIS TIME. THIS PUSHES HIGH PW MOISTURE PLUME EAST OF THE FA BY LATE TUE. HOWEVER...DYNAMICS ALOFT WILL BE MUCH MORE POTENT AND CULD ACTUALLY CONTRIBUTE TO SVR WX ON TUE. 5H TROF LINE ACROSS OR JUST WEST OF THE FA TUE NITE THRU ERLY THU. ENUF MOISTURE REMAINS IN PLACE. DECENT INSTABILITY FROM LOWER TEMPS ALOFT...COMBINED WITH WEAK IMPULSES ALOFT ROTATING THRU UPPER TROF TO AID THE DIURNALLY DRIVEN CONVECTION. WILL CONTINUE POPS AT OR ABOVE CLIMO. FOR THU THRU SAT...UPPER TROF STARTS TO RETROGRESS WESTWARD AS WESTERN ATLANTIC RIDGE BATTLES BACK. THIS WILL CONTINUE THE WET PATTERN ACROSS THE FA WITH CONTINUED POPS AT OR ABOVE CLIMO DURING THIS TIME FRAME. NOCTURNAL ATLANTIC WATER CONVECTION TO RE-APPEAR. WILL NOT BE TOO PICKY IN TRYING TO IDENTIFY ANY UPPER IMPULSES AIDING CONVECTION DURING THIS TIME FRAME. AS FOR TEMPS...MORE OR LESS PERSISTENCE INTO MON. AT OR BELOW CLIMO MAXES. SHULD SEE SOME 90 DEGREE READINGS TUE INTO THU FROM UPPER TROF INFLUENCE. OTHERWISE...BACK TO THE CURRENT READINGS OF LATE DURING THE LATTER PART OF THE EXTENDED. MARINE: AS THE S/SW WIND CONTINUE 10-15 KT THE NEXT SEVERAL PERIODS...WAVEWATCH FORECASTS REVEAL A BUILDING SE SWELL WHICH WILL ADDS TO WIND WAVE HEIGHTS. SWELL CURRENTLY FORECAST AT 2 FT/11 SEC WILL BUILD TO 5 FT/8 SEC AT THE ILM01 FORECAST POINT BY 00Z TONIGHT. WHILE THIS MAY BE OVERDONE SLIGHTLY...CURRENT 4 FT COMBINED SEA FORECASTS LOOK OKAY. MAY TWEAK GRIDS TO SHOW 5 FT JUST OUTSIDE THE 20 MILE FORECAST AREA. FRONTAL BOUNDARY APPROACHES FROM THE WEST TUESDAY...BUT STALLS OUT AS IT ENCOUNTERS THE STRONG WESTERN ATLANTIC RIDGE. FRONT WASHES OUT AND RIDGE REESTABLISHES ITSELF THE LATTER HALF OF THE WEEK WITH S TO SW FLOW CONTINUING. PUBLIC: RALF MARINE: TRA $$ nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 920 PM EDT SUN AUG 3 2003 SURFACE ANALYSIS INDICATES BROAD SOUTHWESTERLY FLOW WITH MANY MESOSCALE BOUNDARIES. KILN SHOWING ISOLATED SHRA/TSRA. WATER VAPOR INDICATES BIG UPPER LOW OVER WESTERN GREAT LAKES WITH SEVERAL EMBEDDED SHORT WAVES WORKING ACROSS OHIO VALLEY. KIND/KVWX SHOWING SCATTERED CONVECTION IN WESTERN INDIANA. RUC AND 18Z MODEL RUNS INDICATE MID LEVEL WAVE WORKING ACROSS FA TONIGHT WITH BIGGER WAVE APPROACHING THE WEST BY MORNING. THESE PARAMETERS ALONG WITH EXTRAPOLATION OF CURRENT CONDITIONS WILL MAKE IT NECESSARY TO KEEP THREAT OF SHRA/TSRA OVER FA ALL NIGHT. WITH THE WEST SEEING A BETTER CHANCE. OTHERWISE FORECAST IS IN GREAT SHAPE. HAVE ALREADY SENT UPDATED FORECAST AND LATEST GRIDS. .ILN...NONE. TIPTON oh AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE STATE COLLEGE PA 725 PM EDT SUN AUG 03 2003 WILL BE UPDATED ZONES EARLY THIS EVENING TO CANCEL THE FLOOD WATCH ACROSS THE WESTERN...CENTRAL...AND NW MTNS WHERE RAINFALL RATES AND COVERAGE HAS DRAMATICALLY DECREASED. WILL LEAVE THE FFA UP THOUGH FOR SEVERAL COUNTIES THROUGHOUT THE WEST BRANCH AND MIDDLE SUSQ VALLEY...WHERE SOME TRAINING SHOWER/TSRA CELLS ARE STILL OCCURRING. 850 HPA THETA-E/PWAT VALUES ARE NOTABLY HIGHER ACROSS THE EAST OVERNIGHT ...AND RUC 40 INDICATES THAT A MESOSCALE AREA OF ENHANCED UVVEL WILL GRADUALLY SHIFT TO THE SOUTHWEST AND EVEN STRENGTHEN LATE THIS EVENING. 18Z ETA MAINTAINS THE BEST FOCUS FOR CONVECTION OVER THE CENTRAL AND LOWER SUSQ VALLEY UNTIL ABOUT 06Z BEFORE IT RAPIDLY DISSIPATES AFTER 06Z SIMILAR TO SATURDAY NIGHT. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ PREVIOUS DISCUSSION BELOW ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ANOTHER BUSY AFTERNOON ACROSS PARTS OF CENTRAL PA AS NUMEROUS TSTORMS DEVELOPING IN VERY MOIST AIRMASS. ACTIVITY AGAIN SHOWING HIGH POTENTIAL FOR TRAINING OVER AREAS WHERE GROUND IS ALREADY NEARLY SATURATED. FLOOD WATCH WILL CONTINUE OVERNIGHT...WITH SEVERAL SPS/S CURRENTLY OUT FOR SPECIFIC CLUSTERS OF HEAVY RAIN. OTHER CONCERN IS ISOLATED SEVERE TSTORMS...MAINLY IN THE W. THESE SHOULD BE ISOLATED AND SHORT-LIVED...BUT ENOUGH TO KEEP A CLOSE EYE ON. PRECIP SHOULD BECOME MORE SCATTERED AND LIGHTER LATER TONIGHT AS VALLEY FOG WILL RETURN. THEN WE START ALL OVER AGAIN TOMORROW WITH ANOTHER WAVE OF SHOWERS AND THUNDERSTORMS. DYNAMICS LOOKING A BIT MORE IMPRESSIVE OVER CENTRAL PA DURING THE DAY MON THAN TODAY...SO WILL AGAIN BE ON THE LOOKOUT FOR SOME STRONG TO POTENTIALLY SEVERE STORMS...ESPECIALLY IF THE REGION CAN GET SOME SUN. WILL ALSO HAVE TO KEEP FLOODING POTENTIAL IN MIND...ALTHOUGH STORMS SHOULD BE MOVING FASTER TOMORROW. REMAINDER OF THE WEEK CONTINUES TO LOOK LIKE HIT AND MISS TSTORMS...ESPECIALLY IN THE AFTERNOONS...AS A VERY MOIST AIRMASS CONTINUES WITH UPPER LOW TO THE WEST. SYSTEM FINALLY STARTS TO MOVE EAST AND THE DRIER AIR BEGINS TO MOVE IN BY THE END OF THE WEEK. .CTP... PA...FLOOD WATCH CANCELLED FOR MUCH OF NORTHERN AND WESTERN PENN. CONTINUED FLOOD WATCH UNTIL 4 AM MONDAY FOR THE MIDDLE SUSQ VALLEY AND A SMALL PORTION OF THE SCENT MTNS. $$ RXR/LAMBERT pa AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 900 PM MDT SUN AUG 3 2003 00Z KUNR SOUNDING SHOWED 90J/KG CAP...BUT LITTLE OR NO CAP FOR ELEVATED CONVECTION IF YOU INJECT MOISTURE INTO THE BOUNDARY LAYER PER MERRIMAN PROFILER/00Z RUC. WELL DEFINED STRONG THETA-E ADVECTION...UP TO 4K/HR...FORECAST TO DEVELOP OVER WESTERN SD OVERNIGHT WITH 40KT LOW LEVEL JET. ELEVATED CAPE OF 0.5-1KJ/KG FORESEEN. DON/T HAVE A LOT OF REASONS TO DISCOUNT THIS FORECAST GIVEN TIGHT SOUTHEASTERLY GRADIENT ALREADY IN PLACE WITH LOWER 60S SURFACE DEW POINTS. HENCE...HAVE UPGRADED MOST OF CWA TO LIKELY POPS WITH EXPECTED MCS DEVELOPMENT. AS FAR AS FIRE WEATHER GOES...RH/S ARE RECOVERING NICELY AND MANY OF THESE STORMS ARE PRODUCING WETTING RAINS WHERE THE BEST LIGHTNING/CORES ARE LOCATED. AFTER TALKING TO LOCAL USFS WILL CANCEL FIRE WEATHER WATCH BEFORE MIDNIGHT FOR BLACK HILLS. WILL ALSO DROP RED FLAG WARNING FOR NORTHEASTERN WY AT THE SAME TIME. UPDATED FORECAST ALREADY OUT THERE. .UNR...RED FLAG WARNING UNTIL MIDNIGHT FOR DRY LIGHTNING ACROSS WYOMING FIRE ZONES 297N...297S...298...299. FIRE WX WATCH FOR DRY LIGHTNING THIS EVENING ACROSS SOUTH DAKOTA FIRE ZONES 260 AND 262. $$ HELGESON sd DEEP SOUTH TEXAS FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 845 PM CDT SUN AUG 3 2003 WATER VAPOR SATELLITE IMAGES AND RUC 200MB STREAMLINE ANALYSIS INDICATE 200MB RIDGE CENTERED OVER THE SOUTHERN ROCKIES WITH A 200MB LOW OVER THE WESTERN GULF OF MEXICO. DEEP SOUTH TEXAS CONTINUES TO BE ON SUBSIDENT SIDE OF THE UPPER LOW OVER THE GULF. THIS IS REFLECTED IN THE 00Z BRO SOUNDING WHICH INDICATED LOWER PRECIPITABLE WATER VALUES COMPARED TO YESTERDAY EVENING. SKIES WERE CLEAR ACROSS THE CWA WITH SOUTHEAST WINDS 15 TO 20 MPH. HIGH CLOUDS OVER CENTRAL TX MAY DRIFT INTO SOUTH TX WITH NORTHEAST WINDS ALOFT. WINDS SHOULD DIMINISH AS THE SUN HAS SET AND HOT TEMPERATURES FROM THIS AFTERNOON ARE MODERATING. WILL UPDATE ZONES/GRIDS TO ADJUST WINDS SLIGHTLY. .MARINE...MODERATE SOUTHEAST WINDS WITH SEAS AT 3 FEET 5 SECONDS PREVAIL AT THE BUOY 35 NM MILES NE OF PORT MANSFIELD THIS EVENING. WINDS OVER THE BAY HAVE ALSO DROPPED SOME. A SCEC IS LIKELY FOR AT LEAST THE BAY MONDAY AS SURFACE WINDS WILL BE OCCASIONALLY STRONG AND GUSTY. .AVIATION...VFR CONDITIONS WILL PREVAIL THE NEXT 24 HOURS AS UPPER RIDGING AND SURFACE HIGH PRESSURE DOMINATE THE LOCAL WEATHER. SOME LOW LEVEL TURBULENCE IS LIKELY DURING THE DAY MONDAY...AS GOOD MIXING IN THE BOUNDARY LAYER WILL ALLOW FOR GUSTY LOW LEVEL WINDS. .BRO...NONE. SYNOPTIC/GRIDS...61 AVIATION/MARINE/MESO...54 $$ THIS PRODUCT IS ALSO AVAILABLE ON OUR INTERNET WEB PAGE AT: HTTP://WWW.SRH.NOAA.GOV/BRO tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 325 PM EDT SUN AUG 3 2003 ******************************************************************* 325 PM EDT SUN AUG 03 2003 ...TONIGHT AND MONDAY... RAIN AMOUNTS TOPPED OUT AROUND AN INCH IN THE HEAVIEST SHOWERS BETWEEN 12Z-19Z. AS EXPECTED...ACTIVITY BECAME STRONGER AGAIN BETWEEN CKB-MGW AND N OF EKN AFT 18Z. NO SERIOUS WATER PROBLEMS DEVELOPED. WILL LET FLOOD WATCH EXPIRE. STILL NEED TO MONITOR RAIN PATTERN NEXT 24 HOURS. BEST COVERAGE EARLY THIS EVENING...OVER OUR MOUNTAINOUS COUNTIES...WHERE IT HAS BEEN DRIER. ALSO COVERAGE SHOULD INCREASE TO OUR WEST...TOWARD COOLER TEMPERATURES ALOFT. MINIMUM OF ACTIVITY THIS EVENING IN THE WESTERN LOWLANDS. LATE NIGHT SHOWERS/THUNDESTORMS COULD THEN MVOE UP OH VLY FROM THE WSW. SO HIGHER POPS LATE TONIGHT IN SOUTHEAST OHIO...NORTHEAST KY ETC...STILL IN THE CHANCE CATEGORY. NO BIG CHANGES MADE TO MONDAY'S FORECAST. ...MONDAY NIGHT THROUGH WEDNESDAY NIGHT... AS LONG AS UPPER TROF REMAINS ACROSS REGION WITH SHORT WAVES MOVING ON THROUGH CAN'T CHANGE FORECAST MUCH FROM A CONTINUATION OF PRIMARILY AFTERNOON AND EVENING SHOWERS/TSTORMS. SURFACE FRONTAL BOUNDARY CROSSES REGION ON WEDNESDAY WITH PERHAPS A GREATER THREAT. ...THURSDAY THROUGH SUNDAY... UPPER TROUGH CONTINUES TO DOMINATE OUR WEATHER THROUGH THE PERIOD...WITH NO REAL END IN SIGHT. KEEPING A DIURNALLY DRIVEN POP IN THE FORECAST WEST OF THE MOUNTAINS ON THURSDAY. SHORTWAVE ROTATING THROUGH TROUGH THURSDAY NIGHT MAY KEEP SOME RAIN GOING IN THE MOUNTAINS SO LEFT SLIGHT CHANCE THERE THROUGH THE NIGHT. MORE DIURNAL POPS ON FRIDAY. TROUGH AXIS IS PROGGED TO BE A BIT FURTHER EAST ON SAT/SUN THAN IN WAS IN GFS RUNS YESTERDAY...KEEPING NEXT SHORTWAVE EAST OF THE MOUNTAINS FOR THE MOST PART. THIS MAY ACTUALLY PROVIDE A BREAK FROM THE RAINS...PARTICULARLY IN THE WESTERN COUNTIES. WENT WITH MORE DIURNAL POPS SATURDAY EAST OF THE OHIO...WITH A DRY FORECAST ALONG AND WEST. GOING WITH AN OPTIMISTIC DRY FORECAST ON SUNDAY AREAWIDE AS TROUGH EDGES FURTHER EASTWARD STILL. THIS OF COURSE MAY CHANGE CONSIDERING HOW THIS SUMMER HAS PROGRESSED. TEMPS IN GOOD AGREEMENT WITH MEX/ISC OVERALL AND DID NOT MAKE ANY MAJOR CHANGES. .RLX... WV...NONE. VA...NONE. KY...NONE. OH...NONE. BATTY/DB/CL ******************************************************************* 1020 AM EDT SUN AUG 3 2003 SHOWERS WITH FEW EMBEDDED T WILL BE EXITING TRI STATE VICINITY HTS ARND 16Z AS IT MOVES NE AROUND 25-30 KNOTS. RAIN RATES NOT HEAVY ENOUGH FOR WATER PROBLEMS. MAY INTENSIFY CKB-EKN DURING THE 17-19Z PERIOD...BUT WILL KEEP CRW-PKB-BKW RELATIVELY STABLE FOR THE EARLY AFTERNOON. ADJUSTED HOURLY DEPICTION OF SKY...TEMPERATURES...POPS ETC FOR TODAY BASED ON MOVEMENT OF EXISTING CONVECTION. LIKELY POPS IN SOME COUNTIES FOR TONIGHT MAY BE TOO HIGH...WILL EVALUATE ON CURRENT SHIFT. AT THIS MOVEMENT...88D RADAR CONTINUES DOWN FOR HARDWARE REPLACEMENT. BATTY ******************************************************************* 314 AM EDT SUN AUG 03 2003 ...TODAY THROUGH MONDAY... UPPER LOW CONTINUES TO SPIN...OVER LAKE SUPERIOR EARLY THIS MORNING. VORT MAX OVER IL/IN EVIDENT IN RADAR IMAGERY AND WELL DEPICTED BY MESO ETA...AND TO LESSER EXTENT ON GFS. THIS APPEARS TO BE PHASING IN WITH A WEAKER SHORT TO THE SOUTH AND EAST...THE WHOLE THING LIFTS THROUGH MY WESTERN COUNTIES THIS MORNING AND MIDDAY....ALONG WITH LOW LEVEL CONVERGENCE AXIS. THINK WILL OPT TO CANCEL WATCH OVER MY SOUTHEASTERN COUNTIES AND EXTEND WATCH THROUGH 4 PM TODAY WHERE IN PLACE ELSEWHERE. ANOTHER WEAK SHORT ROTATES AROUND MAIN UPPER VORTEX TONIGHT AND YET ANOTHER MONDAY AFTERNOON. PWS LOWER A LITTLE BY MONDAY BUT STILL OVER AN INCH. GENERALLY ROLLED WITH MOS IN TEMPERATURES BUT BELOW ON POPS...DID NOT QUITE GO WITH CATEGORICAL NUMBERS TODAY. ...MONDAY NIGHT THROUGH SATURDAY... THE UPPER LOW CONTINUES OVER THE GREAT LAKES REGION...WITH VORTICES ROTATING THROUGH THE BASE OF THE LOW. THE UPPER LOW FINALLY GRADUALLY MOVES NORTHEAST WHICH CAUSE THE TROUGH TO MOVE EAST TO THE WESTERN SECTIONS OF THE FORECAST AREA BY WEDNESDAY. THE UPPER TROUGH REMAINS WEST OF THE FORECAST AREA THROUGH SATURDAY. DUE TO ABUNDANT MOISTURE AND THE WET PATTERN WE ARE IN THE FORECAST IS RIGHT ON TARGET WITH LITTLE OR NO CHANGES AT THIS TIME. THE TEMPERATURES ARE IN THE BALLPARK. TRM/ELW ******************************************************************* 954 PM EDT SAT AUG 02 2003 TSTMS WINDING DOWN PER LATEST 5 MIN LIGHTNING DATA. SCATTERED SHOWERS CONTINUE TO POP UP...ALTHOUGH WITH PWATS AROUND 1.8 AND WARM CLOUD DEPTH OF 11KFT OPTED TO LET FFA CONTINUE. MOST OF THE AFTERNOON RAINS THE GROUND RECEIVED WELL...HIGHEST AMOUNT WHERE INCH TO INCH AND A HALF JUST EAST OF THE MARIETTA AREA WHERE A STORM FORMED ON A STATIONARY BOUNDARY. PRESENT GRIDS ARE COORDINATED WELL AND REFLECT LATEST RUC...WITH MID LEVEL WAVE MOVING AROUND 09Z INC AREAL COVERAGE OF PRECIP...THUS NO EVENING UPDATE PLANNED. 29 ******************************************************************* wv AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 1020 AM EDT SUN AUG 3 2003 1020 AM EDT SUN AUG 3 2003 SHOWERS WITH FEW EMBEDDED T WILL BE EXITING TRI STATE VICINITY HTS ARND 16Z AS IT MOVES NE AROUND 25-30 KNOTS. RAIN RATES NOT HEAVY ENOUGH FOR WATER PROBLEMS. MAY INTENSIFY CKB-EKN DURING THE 17-19Z PERIOD...BUT WILL KEEP CRW-PKB-BKW RELATIVELY STABLE FOR THE EARLY AFTERNOON. ADJUSTED HOURLY DEPICTION OF SKY...TEMPERATURES...POPS ETC FOR TODAY BASED ON MOVEMENT OF EXISTING CONVECTION. LIKELY POPS IN SOME COUNTIES FOR TONIGHT MAY BE TOO HIGH...WILL EVALUATE ON CURRENT SHIFT. AT THIS MOVEMENT...88D RADAR CONTINUES DOWN FOR HARDWARE REPLACEMENT. .RLX... WV...FLOOD WATCH TODAY FOR WVZ005>011-013>020-024>032-039-040. VA...NONE. KY...FLOOD WATCH OVERNIGHT FOR KYZ101>103-105. OH...FLOOD WATCH OVERNIGHT FOR OHZ066-067-075-076-083-084-085>087. BATTY ******************************************************************* 314 AM EDT SUN AUG 03 2003 ...TODAY THROUGH MONDAY... UPPER LOW CONTINUES TO SPIN...OVER LAKE SUPERIOR EARLY THIS MORNING. VORT MAX OVER IL/IN EVIDENT IN RADAR IMAGERY AND WELL DEPICTED BY MESO ETA...AND TO LESSER EXTENT ON GFS. THIS APPEARS TO BE PHASING IN WITH A WEAKER SHORT TO THE SOUTH AND EAST...THE WHOLE THING LIFTS THROUGH MY WESTERN COUNTIES THIS MORNING AND MIDDAY....ALONG WITH LOW LEVEL CONVERGENCE AXIS. THINK WILL OPT TO CANCEL WATCH OVER MY SOUTHEASTERN COUNTIES AND EXTEND WATCH THROUGH 4 PM TODAY WHERE IN PLACE ELSEWHERE. ANOTHER WEAK SHORT ROTATES AROUND MAIN UPPER VORTEX TONIGHT AND YET ANOTHER MONDAY AFTERNOON. PWS LOWER A LITTLE BY MONDAY BUT STILL OVER AN INCH. GENERALLY ROLLED WITH MOS IN TEMPERATURES BUT BELOW ON POPS...DID NOT QUITE GO WITH CATEGORICAL NUMBERS TODAY. ...MONDAY NIGHT THROUGH SATURDAY... THE UPPER LOW CONTINUES OVER THE GREAT LAKES REGION...WITH VORTICES ROTATING THROUGH THE BASE OF THE LOW. THE UPPER LOW FINALLY GRADUALLY MOVES NORTHEAST WHICH CAUSE THE TROUGH TO MOVE EAST TO THE WESTERN SECTIONS OF THE FORECAST AREA BY WEDNESDAY. THE UPPER TROUGH REMAINS WEST OF THE FORECAST AREA THROUGH SATURDAY. DUE TO ABUNDANT MOISTURE AND THE WET PATTERN WE ARE IN THE FORECAST IS RIGHT ON TARGET WITH LITTLE OR NO CHANGES AT THIS TIME. THE TEMPERATURES ARE IN THE BALLPARK. TRM/ELW ******************************************************************* 954 PM EDT SAT AUG 02 2003 TSTMS WINDING DOWN PER LATEST 5 MIN LIGHTNING DATA. SCATTERED SHOWERS CONTINUE TO POP UP...ALTHOUGH WITH PWATS AROUND 1.8 AND WARM CLOUD DEPTH OF 11KFT OPTED TO LET FFA CONTINUE. MOST OF THE AFTERNOON RAINS THE GROUND RECEIVED WELL...HIGHEST AMOUNT WHERE INCH TO INCH AND A HALF JUST EAST OF THE MARIETTA AREA WHERE A STORM FORMED ON A STATIONARY BOUNDARY. PRESENT GRIDS ARE COORDINATED WELL AND REFLECT LATEST RUC...WITH MID LEVEL WAVE MOVING AROUND 09Z INC AREAL COVERAGE OF PRECIP...THUS NO EVENING UPDATE PLANNED. 29 ******************************************************************* 320 PM EDT SAT AUG 02 2003 ...TONIGHT AND SUNDAY... WILL POST A "SUMMER" FLOOD WATCH OVER WETTEST AREAS...DUE TO MOIST AIR AND UPPER AIR SUPPORT OVERNIGHT. "SUMMER" WATCHES MEANS SOME AREAS IN THE WATCH COULD EVEN MISS THE SHOWERS COMPLETELY...BUT THERE IS STILL A THREAT OF LOCALIZED DOWNPOURS...EVEN LATE AT NIGHT. RAINS AROUND 2 INCHES WOULD START CAUSING SOME PROBLEMS. THE CONVECTION NR BWG ON W OF BNA AT 18Z COULD INTERCEPT SOME OF THE MOISTURE - SPARING OUR WATCH AREA. BEST TO PLAY ON THE SAFE SIDE AND ALERT FLOOD PRONE AREAS...SINCE EVEN THE 3 HOURLY FLASH FLOOD GUIDANCE IS UNDER 2 INCHES OR LESS. WILL GO LIKELY POPS ON SUNDAY...THOUGH HARD TO FIGURE HOW LEFTOVER MORNING SHOWERS WILL AFFECT THE AFTERNOON CONVECTION PATTERN. DEPENDING ON WHAT HAPPENS OVERNIGHT...A FLOOD WATCH MAY STILL BE NEEDED FOR SOME COUNTIES ON SUNDAY. BUT DID NOT WANT TO TIE THE HANDS OF MIDNIGHT SHIFT. ...SUNDAY NIGHT THROUGH TUESDAY NIGHT... SOME SEMBLANCE OF A SURFACE FRONT PUSHES THROUGH SUNDAY NIGHT...AS MAIN UPPER TROUGH AXIS APPROACHES FROM THE WEST. THIS POINTS TO GOOD CHANCE TO LIKELY POPS...ESPECIALLY EARLY...BUT MODEL FORCING IS SHOWN TO BE WEAK AT BEST DESPITE THESE FEATURES. MONDAY... BOUNDARY IS BASICALLY EAST OF AREA BUT UPPER LOW IS CLOSE BY TO THE WEST. THIS SUPPORTS GOOD CHANCE PARTICULARLY FOR THE AFTERNOON. LITTLE LOWER POPS ON TUESDAY AS UPPER SYSTEM WEAKENS AND PW AND INSTABILITY IS LESS. MOS ON OR CLOSE ALL AROUND. ...WEDNESDAY THROUGH SATURDAY... THE NEVER-ENDING TROUGH MAINTAINS ITSELF THROUGH THE PERIOD. 00Z GFS GIVES US SOME HOPE OF SEEING RISING HEIGHTS BY THE VERY END OF THE FORECAST PERIOD...BUT IT IS HARD TO BUY INTO THAT AT THIS POINT. LITTLE CHANGE TO THINKING FOR WEDNESDAY AND THURSDAY...AS DIURNAL POPS STILL LOOK GOOD. DID EXTEND 30 PERCENT CHANCES ACROSS ENTIRE CWA ON THURSDAY HOWEVER. SHORTWAVE SYSTEM SWINGING AROUND TROUGH ON FRIDAY LEADS TO ADDITION OF RAIN CHANCES ON THAT DAY...BEST IN THE MOUNTAINS CLOSEST TO SYSTEM AND BETTER ACCESS TO MOISTURE. THIS SYSTEM DEPARTS BY SATURDAY...BUT LINGERING MOISTURE...POSSIBLE PRESENCE OF INVERTED SURFACE TROUGH...AND THE COURSE OF THIS SUMMER LEAD ME TO ADD RAIN CHANCES ONCE AGAIN FOR SATURDAY. TEMPS REMAIN AT OR JUST BELOW NORMAL LEVELS THROUGH THE EXTENDED PERIOD. MINOR TWEAKS TO THESE GRIDS...ALREADY IN DECENT AGREEMENT WITH MEX AND ISC. BATTY/TRM/CL ******************************************************************* 1 wv SOUTH CENTRAL AND SOUTHEAST COLORADO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO 308 AM MDT MON AUG 4 2003 SHORT TERM DISCUSSION...(TODAY/TONIGHT). BIGGEST CHALLENGE TODAY WILL BE THE POTENTIAL FOR SHRA/TSRA AND HOW HOT WILL IT GET. CURRENTLY: WATER VAPOR IMAGERY AND RUC MODEL UPPER AIR ANALYSES SHOWED AN UPPER LEVEL DRYING TREND OCCURRING ACROSS WRN CO FROM THE DEEP "DRY" AIRMASS TAP IN THE GREAT BASIN AND CA. APPEARS TO STILL BE SOME MOISTURE IN THE MID LEVELS. DECAYING MCS(WARMING TOPS) ACROSS THE CNTRL PLAINS CONTINUING TO FORWARD PROPAGATE AWAY FROM ERN CO PER IR SATELLITE IMAGERY ANIMATION. A FEW RENEGADE SHRA WERE OCCURRING AROUND THE ERN PORTION OF THE PALMER DIVIDE. SFC DEW POINTS HOLDING TIGHT IN THE 50S/NR 60 IN SERN CO AND 30S/40S/LOWER 50S IN THE HIGHER ELEVATIONS. SFC TEMPS HAVE BEEN SLOW TO COOL THANKS TO THE CONVECTIVE DEBRIS CLOUDS OVERHEAD...BUT THEY ARE BREAKING UP AND WE SHOULD SEE TEMPS DROP A FEW MORE DEGREES. TDA: UPPER HIGH SHOULD CONTINUE TO BE CENTER JUST SOUTH OF CO IN NM WITH RELATIVELY FASTER(15-25KTS) FLOW IN THE MID LEVELS JUST NORTH OF THE HIGH. A FEW MINOR SHORTWAVE TROUGHS ARE STILL PROGGED TO MOVE THROUGH THE FLOW. WE SHOULD SEE SFC DEW POINTS DROP TODAY WITH PLENTY OF MIXING(UP TO 550MB). A DRYLINE...OR LOW LEVEL CONVERGENCE ZONE... SETS UP IN THE FAR SERN CO PLAINS WHICH COULD BE A FOCAL POINT FOR TSTMS LATE THIS AFTN/EVE. ALSO...WITH SOME LOW/MID LEVEL MOISTURE STILL AROUND AND SURFACE HEATING DESTABILIZING THE ATMOSPHERE...COULD NOT RULE OUT A COUPLE OF SHRA/TSRA FORMING IN THE HIGH COUNTRY THIS AFTERNOON AND MOVING E-SEWD. LIFTED INDICES ARE PROGGED TO BE AROUND -6C AND JUXTAPOSED WITH 0-6KM SHEAR VALUES OF 30-40KTS IN SERN CO THIS AFTN/EVE. COULDN'T RULE OUT ONE OR TWO 3/4 INCH DIAMETER HAILSTONE TSTMS IN SERN CO...BUT IT IS GOING TO BE ANOTHER WARM DAY WITH HIGH FREEZING AND WET BULB ZERO LEVELS. WE HAVE BEEN CONSISTENTLY MIXING DRY ADIABATICALLY TO AROUND 550MB...SO DO NOT SEE WHY THIS WILL NOT CONTINUE. THIS PUTS ELEVATIONS BELOW 6K FT MSL AROUND 95-100F THIS AFTN. THE MAV MOS GUIDANCE IS BY FAR THE COOLEST AND PAST LOCAL TEMP STUDIES SHOW THIS MODEL CONSISTENTLY 5-6 DEGREES TOO COOL THIS SUMMER...IN SOME CASES 10+ DEGREES TOO COOL. TWEAKED CURRENT FCST GRIDS UP JUST A TAD BASED ON WHAT OCCURRED YDA. THIS IS STILL A FEW DEGREES ABOVE THE MET(ETA) MOS GUIDANCE WHICH IS THE WARMEST OF ALL MOS GUIDANCE FOR THE MOST PART. TNGT: ANY SMALL PRECIP CHANCES WILL BE CONFINED TO THE EARLY EVE HOURS. THE CONVECTIVE DEBRIS CLOUDS SHOULD DISSIPATE THROUGH THE NGT. CHALLENGING DEW POINT FORECAST...AS THERE WILL LIKELY BE SOME RECOVERY OVERNIGHT...BUT IF ANY WIND PICKS UP...THEN IT COULD GET MIXED OUT. CURRENT FCST MINS LOOKED ON TARGET. --METZE LONG TERM DISCUSSION...(TUESDAY THROUGH SUNDAY). NOT MUCH CHANGE TO CURRENT GRIDS. MODELS ADVERTISE SLIGHTLY COOLER TEMPS FOR TUESDAY...THOUGH WILL CONTINUE TO KEEP THEM ABOVE GUIDANCE. MOISTURE IS FAIRLY LIMITED ON TUESDAY THOUGH WITH AFTN HEATING AND RESIDUAL MID LVL MOISTURE...SLIGHT CHANCE POPS OVER MTNS AND ADJACENT INTERSTATE 25 CORRIDOR STILL LOOKS GOOD. WEDNESDAY HEATS BACK UP AGAIN...WITH ETAX BRINGING 700 TEMPS BACK UP TO AROUND +17 C. THIS COULD BODE FOR SOME AROUND 100 DEGREE READINGS FOR THE LOWER ARKANSAS RIVER VALLEY. WITH LEE TROF ACROSS SOUTHEAST PLAINS...DRY LINE SETS UP ALONG CO/KS BORDER. ETA SHOW SOME CAPES OF AROUND 1500 J/KG WITH LIS OF -4 AND 0-6KM SHEARS AROUND 30 KTS. SO...SOME POTENTIAL EXISTS FOR STRONG STORMS POSSIBLE NEAR THE CO/KS BORDER. CURRENT GRIDS HAVE ISOLATED POPS FOR ALL AREAS...AND THIS STILL LOOKS GOOD. FOR THURSDAY AND FRIDAY...MID LEVEL FLOW BECOMES MORE SOUTHERLY AS UPPER RIDGE AXIS SHIFTS SLIGHTLY EAST OF THE AREA. AVN SUGGESTS AN INCREASE IN MOISTURE FOR THE SOUTHWEST MTNS OF FCST AREA...AND HAVE BUMPED UP POPS A BIT TO ACCOUNT FOR THIS...AND TO BETTER BLEND WITH ISC GRIDS. GFS SHIFTS UPPER HIGH WESTWARD FOR SUNDAY AND MONDAY...SUGGESTING MONSOON MOISTURE TAP WILL BE WEST OF THE AREA. STILL COULD BE SOME RESIDUAL MOISTURE RECIRCULATING THROUGH UPPER HIGH. WOULD EXPECT A GENERAL DECREASE IN AFTERNOON THUNDERSTORM COVERAGE...AND POSSIBLY SOME WEAK COLD FRONTS WHICH TRY TO PENETRATE INTO SOUTHEAST PLAINS. CURRENT GRIDS LOOK GOOD. -KT .PUB...NONE. co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREEN BAY WI 445 AM CDT MON AUG 4 2003 PRIMARY FCST CONCERN ONCE AGAIN IS CHC OF SHOWERS AND THUNDERSTORMS FOR THIS AFT INTO THE EVENING. WATER VAPOR IMAGERY EARLY THIS MORNING SHOWS UPPER CIRCULATION THAT HAS PERSISTED OVR FCST AREA FOR PAST SEVERAL DAYS HAS FINALLY DRIFTED EAST INTO WESTERN LOWER MI. HOWEVER SEVERAL DISTURBANCES CONTINUE TO ROTATING AROUND THE UPPER LOW. THE MOST POTENT DISTURBANCE CURRENTLY HEADIND SOUTH ACROSS SOUTHERN IL HAS GENERATED THUNDERSTORMS THERE. ANOTHER STRONG DISTURBANCE HEADING NORTH ACROSS LAKE HURON ASSOCIATED WITH DECENT COMMA CLOUD/PRECIP SHIELD EXPANDING INTO EASTERN ONTARIO PROVINCE. THE THIRD IMPULSE CURRENTLY LOCATED OVER EASTERN UP OF MI... WILL AFFECT OUR FORECAST AREA TODAY. RUC AND META IN GENERAL AGREEMENT ON BRINING THIS DISTURBANCE SOUTHWARD ACROSS EASTERN WI DURING THE DAY. IR2 IMAGERY SHOWS AREA OF LOW CLOUDS EXPANDING SOUTHWEST ACROSS THE FORECAST AREA WITHIN COOL AND MOIST LOW-LVL NORTHEAST FLOW. RADAR DATA INDICATES ONLY PATCHY LIGHT SHOWERS OVR EASTERN UP OF MI ATTM HEADING SOUTHWEST. MAIN QUESTION WILL BE HOW MUCH ATMOSPHERE WILL BE ABLE TO DESTABILIZE FOR MORE WIDESPREAD SHWRS AND TSTSM THIS AFTERNOON. RUC AND META FCST SOUNDINGS CONTINUE TO SUGGEST A FAIR AMOUNT OF INSTABILITY BY EARLY AFT...ESPECIALLY OVR THE NORTHEAST AND EASTERN PORTION OF THE FORECAST AREA WITH LI/S FALLING TO -2 AND CAPES APPROACHING 1000-1200 J/KG. HOWEVER...THE DEGREE TO WHICH THIS INSTABILITY WILL BE REALIZED WILL DEPEND ON HOW PERSISTANT THE LOW CLDS WILL BE. RUC ALSO HINTING AT SOME ENHANCED BLYR MCON OVR NORTHEAST WI THIS AFT...POSSIBLY IN RESPONSE TO DEVELOPMENT OF WEAK LAKE BREEZE. LIKE YESTERDAY...EXPECT THE LOCATION OF ANY CONVECTION THAT DEVELOPS TO BE MODULATED BY ANY WEAK BOUNDARIES. WITH CENTER OF UPPER LOW TO OUR EAST...MID-LEVEL STEERING WINDS FCST TO BE A BIT STRONGER THIS AFT COMPARED TO YESTERDAY...ESPECIALLY OVER CENTRAL PORTIONS OF THE FORECAST AREA. ANY THUNDERSTORMS THAT DO DEVELOP SHOULD NOT BE QUITE AS SLOW MOVING....HOWEVER WINDS ONLY FORECAST TO BE IN THE 15 TO 20 KT RANGE IN EASTERN WI. GIVEN AVAILABLE DEEP LAYER MOISTURE...EXPECT ANY STORMS THAT DEVELOP OVER EASTERN WI TO STILL HAVE POTENTIAL TO PRODUCE LOCALLY HEAVY RAINFALL...ALTHOUGH THE STORMS ARE EXPECTED TO BE LESS NUMEROUS COMPARED TO PAST FEW DAYS. AFT A FEW EVENING SHOWERS...SKIES SHOULD BECOME PARTLY CLDY OVERNIGHT. WITH LIGHT NE WINDS AND AMPLE BLYR MOISTURE...EXPECT AREAS OF FOG TO DEVELOP OVR MOST OF FORECAST AREA. UPR LOW TO ONLY SLOWLY DRIFT EAST NEXT FEW DAYS AS HEIGHTS OVR WESTERN US FCST TO BUILD NORTHWARD INTO CENTRAL CANADA BY MID WEEK. MODELS CONTINUE TO HINT ON BRINING WEAK DISTURBANCES ACROSS FORECAST AREA WITHIN THE NW FLOW REGIME DURING FIRST HALF OF THE WEEK. TIMING OF DISTURBANCE TRICKY...BUT MENTION OF PRECIP MAINLY DURING THE AFT HOURS THROUGH WED STILL LOOKS REASONABLE...THUS LEFT REMAINDER OF FORECAST IN TACT. .GRB...NONE. $$ EB WWW.CRH.NOAA.GOV/GRB wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 645 AM EST MON AUG 4 2003 AVIATION DISCUSSION FOR 12Z... MAIN CHANGE WAS TO ADD VCTS AT KSBN AND HIT TSRA HARDER WITH TEMPO GROUP AT KFWA. ELONGATED SHORTWAVE AND ASSOCIATED 5H COLD POOL ROTATING THROUGH IN/IL BORDER AREA AND WILL GIVE DECENT SHOT OF PVA/LIFT TO KFWA AREA BY ABOUT 18Z. MEANWHILE RUC40 SOUNDINGS INDICATE MODERATE INSTABILITY WITH SURFACE BASED CAPES 2500-3000 J/KG AT KFWA AND LESSER AROUND 1800 J/KG AT KSBN. PROXIMITY OF WEAK SURFACE TROF SHOULD ALSO ASSIST IN INITIATING DEEP MOIST CONVECTION FAIRLY EARLY THIS AFTERNOON. HAVE TRIED TO KEY ON BEST TIMING WITH 3 HOUR PERIOD OF VCTS AT KSBN 18Z-22Z AND TEMPO AT KFWA 19Z-22Z. NEXT AVIATION FORECAST PROBLEM WILL BE FOG/ST DEVELOPING AS TOP OF MOIST BOUNDARY LAYER COOLS...HAVE FORECAST DOWN TO CRITICAL 2SM BR CIGS 006 FOR NOW...SUSPECT THAT KFWA COULD GO LIFR 10Z-12Z ESPECIALLY IF AIRPORT HIT WITH DECENT RAINFALL TODAY...HOWEVER WILL LET THIS DETAIL EVOLVE IN FUTURE FORECASTS IF DEEMED MORE LIKELY. PBM WEAK SFC LOW CENTERED NEAR CHI AT 6Z. SOME CONVECTION CONTINUES IN RESPONSE TO ANOTHER SHORTWAVE OVER ILLINOIS. THIS WILL CONTINUE TO MOVE SE AND THEN ELONGATE SOMEWHAT INTO THE EASTERN PART OF THE CWA THIS AFTERNOON. MAY NEED SOME SCT WORDING IN THE EAST THIS AM DEPENDING ON RADAR TRENDS. INSTABILITY WILL NOT BE AS HIGH AS PAST COUPLE OF DAYS...BUT WITH UPR LOW STILL IN THE AREA...SCT POPS LOOK GOOD FOR ALL AREAS AFTN/EARLY EVE...WITH LOWER POPS WEST. CAN'T RULE OUT AN ISOLATED SVR STORM...MUCH LIKE THE PAST COUPLE OF DAYS...IN THE EAST...BUT NOT ENOUGH CONFIDENCE/COVERAGE TO MENTION IN ZONES. PW'S NOT AS HIGH TODAY...BUT SLOW MVMT OF CONVECTION WARRANTS HEAVY RAIN MENTION. QUESTION IS WILL ANY PRECIP OCCUR TUES OR WEDS. MODELS HAVE BEEN TRENDING ON BEST DYNAMICS/INSTABILITY TO SHIFT EAST WITH THE UPR LOW. COULD END UP DRY ON TUESDAY...BUT WILL KEEP LOW AFTN/EVE POPS EVERYWHERE EXCEPT FAR SW/W COUNTIES. DRY MONDAY AND TUES NGT...WITH CHC POPS ON WEDS ALL AREAS AS ONE LAST PIECE OF ENERGY MOVES ALONG THE BACK OF THE TROUGH. NO CHANGES TO TEMP GRIDS WITH TEMPS REMAINING BELOW NORMAL UNTIL DEPARTURE OF TROUGH. FISHER DY3-7 DISCUSSION... FEW CHANGES TO GOING GRIDS. UPPER LEVEL TROF SHOULD BE EAST OF FORECAST AREA ENOUGH TO BEGIN DRY GRIDS ON THURSDAY. THEN PATTERN BECOMES LOCKED WITH TROF ACROSS APPALACHIAN FRONT AND RIDGE STRENGHTENING FROM PLAINS NORTH-NORTHEAST INTO SOUTH CENTRAL CANADA PER GFS AND GEM. ONLY POTENTIAL PROBLEM IS GFS NOW HINTS AT 5H CUTOFF DEVELOPING IN/OH BORDER SATURDAY INTO SUNDAY THAT WILL NEED TO BE MONITORED. FOR NOW WILL DISCOUNT AND CONTINUE DRY THROUGHOUT REMAINDER OF EXTENDED WITH SLOW TREND TOWARD NORMAL TEMPS AS AIRMASS SHOULD MODIFY WARMER AS NORTH TO NORTHEAST FLOW GRADUALLY WEAKENS. PBM .IWX... IN...NONE. MI...NONE. OH...NONE. $$ in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1140 AM EDT MON AUG 04 2003 ...UPDATED FORECAST FOR AFTERNOON WORDING... NO BIG CHANGES SEEN FROM EARLY MORNING FORECAST. HOWEVER...IT SHOULD BE NOTED THAT THE UPPER LEVEL TROUGH IS FARTHER EAST THEN IT WAS SUNDAY. THE VAD WIND AT GRR SHOWS NORTH WINDS THROUGH 6000 FT THEN NORTHEAST WINDS THROUGH 10000 FT. THE WATER VAPOR LOOPS AND THE RUC SUGGEST THAT THE AXIS OF THE UPPER TROUGH IS NEAR US-131. SO... UNLIKE SUNDAY...WERE THERE WAS DECENT WIND CONVERGENCE ON THE LAKE BREEZE BOUNDARY... I DO NOT SEE THAT TODAY. WITH THE SHORTWAVE SEEN ON THE IR AND WATER VAPOR LOOPS ROTATING NORTHEAST FROM IN/OH TOWARD WESTERN LAKE ERIE THIS EVENING... I EXPECT THE BEST CONVECTION TO BE FARTHER EAST TODAY... LIKELY EAST OF US 131. EVEN SO... USING THE RUC SOUNDING IN AWIPS AT 15Z I STILL GET 1500 J/KG AND CLOUD TOPS TO NEAR 48000 FT AT GRR! IF I USE THE FORECAST MAX TEMP (WHICH IS ABOUT 80F) WE COULD GET 2500 J/KG WITH CLOUD TOPS TO NEAR 50000 FT. THING IS THE TROP IS AT 35000 FT. GIVEN THE FREEZING LEVEL NEAR 11,500 FT AND THE LOW AMOUNT OF WIND SHEAR AND LIGHT STEERING WINDS I COULD SEE ISOLATED SEVERE THUNDERSTORMS THIS AFTERNOON (MOSTLY EAST OF GRR) WITH HAIL TO 1 INCH AS THE PRIMARY SEVERE EVENT. I COULD ALSO SEE THE NEED FOR A FEW URBAN AND SMALL STREAM FLOOD ADVISORIES FOR SLOW MOVING THUNDERSTORMS PRODUCING LARGE AMOUNTS OF RAIN OVER A SMALL AREA. WE WILL BE WATCHING FOR BOTH. LIKE SUNDAY... ALL OF THIS SHOULD END BY LATE EVENING THEN FOG IS LIKELY TO REDEVELOP. THE ZONE UPDATE HAS ALREADY BEEN ISSUED. WDM .GRR...NONE. $$ mi SOUTHEAST MICHIGAN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1035 AM EDT MON AUG 4 2003 12Z SOUNDING HERE CONTINUES TO SHOW WEAK STEERING FLOW AND MINIMAL SHEAR. HOWEVER... SEVERAL BOUNDARIES ALONG WITH A SHORT WAVE ROTATING OVER CENTRAL INDIANA (SEEN QUITE WELL ON THE H2O VAPOR) AND UPPER LOW ALMOST OVERHEAD SHOULD BE ENOUGH FOR CONVECTION TO FIRE THIS AFTERNOON. MODIFYING OUR 12Z SOUNDING WITH 79/63 SUPPORTS CAPES AROUND 2000 J/KG WITH SFC BASED LI/S NEAR -5C. CONVECTIVE TEMPERATURES ARE IN THE UPPER 70S WHICH SHOULD NOT BE A PROBLEM ALONG AND SOUTH OF M59. NORTH OF THIS BOUNDARY WE CONTINUE WITH IFR CEILINGS AND VISIBILITIES WHICH DOES NOT APPEAR TO BE ERODING THAT QUICKLY THIS MORNING. THIS MAY SET UP A DIFFERENTIAL HEATING BOUNDARY COMBINING WITH LAKE BREEZE DEVELOPMENT FOR CONVECTION TO FIRE UP JUST ABOUT ANYWHERE...INITIALLY ALONG AND SOUTH OF M59. LATEST RUC SUPPORTS THIS IDEA WITH POPCORN CONVECTION DEVELOPING NEAR 18Z. BGM __FULL AM DISCUSSION FOLLOWS__ NOT A LOT OF CHANGES PLANNED THIS FORECAST PACKAGE FOR SOUTHEAST MI. WILL CONTINUE THE ISOLATED SHOWER MENTION THIS MORNING EXCEPT CHANCE SHOWERS/THUNDER SOUTHERN 4 COUNTIES BASED ON PERSISTENT AREA OF CONVECTION WORKING UP FROM THE SOUTHWEST...THEN SCATTERED/50 PERCENT POPS THIS AFTERNOON AND EVENING. WILL TWEAK TODAY HIGH TEMPERATURES UP JUST ABOUT A DEGREE BASED ON SOME MORNING SUN AND TRAJECTORY FORECASTS. OTHERWISE ONLY REAL CHANGE WILL BE TO ADD FOG MENTION TO EARLY THIS MORNING AND AGAIN LATE TONIGHT AND EARLY TUESDAY MORNING. SYNOPTIC PATTERN A VERY SLOWLY PROGRESSIVE ONE. CLOSED 500 MB LOW OVERHEAD TODAY AND TONIGHT THEN CRAWLING EAST...WITH CYCLONIC FLOW THEN LINGERING BACK ACROSS FORECAST AREA...WITH PREFERENCE FOR CONSENSUS OF MODELS BEING A LITTLE SLOWER THAN GFS IN RETREATING SYSTEM EAST. AT THE SURFACE...WEAK PRESSURE GRADIENT/WINDS THROUGH TONIGHT AND CARRYING OVER THROUGH TUESDAY AT LEAST AS BROAD TROUGH BENEATH UPPER LOW PERSISTS...MAKING IT HARD FOR RIDGE TO NUDGE IN FROM THE WEST. AS FOR SYNOPTIC SCALE FORCING...ONLY SLIGHT OMEGA LIFT IN LOW TO MID LEVELS THIS AFTERNOON/EVENING AND AGAIN BY TUESDAY AFTERNOON INTO TUESDAY NIGHT...JUST A BIT WEDNESDAY INTO WEDNESDAY NIGHT. REASONABLY DEEP MOISTURE REMAINING IN PLACE AT LEAST THROUGH TUESDAY BEFORE LESSENING SOMEWHAT...WHILE 925 MB MOISTURE PERSISTS QUITE GOOD. 850 TO 500 MB QVECTOR CONVERGENCE WEAK INTO TUESDAY...WITH DIFFERENTIAL PVA WEAK AT BEST. MODEST SURFACE CONVERGENCE PREVAILS...THOUGH...THROUGH MID WEEK. CONVECTION EXPECTED TO FIRE AGAIN...ESPECIALLY AFTERNOON AND EVENING HOURS NEXT 2 TO 3 DAYS. WITH WIND FIELDS SURFACE AND ALOFT RATHER WEAK IN PROXIMITY TO LOW/TROUGH...WOULD NOT EXPECT ANY ORGANIZED THUNDERSTORM WIND EVENTS...AND WITH WET BULB ZERO AROUND 10K FEET COULD SEE SOME HAIL WITH ANY STRONG STORMS. MODEL CAPES... THOUGH...ARE RATHER MODEST...ON ORDER OF 1000 JOULES...WHILE AFTERNOON LIFTED INDICES GET SOMEWHAT UNSTABLE. WOULD AGAIN ANTICIPATE LAKE BREEZES TO PLAY A ROLE IN PROVIDING INITIAL FOCUS FOR THUNDERSTORM DEVELOPMENT BOTH TODAY AND TUESDAY. .DTX...NONE. $$ DWD 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 955 AM EDT MON AUG 4 2003 12Z RAOBS/WV LOOP AND RUC ANLSYS SHOW PESKY UPR LO OVR WCNTRL LWR MI MOVG VERY SLOWLY SE. SHRTWV ON NE FLANK OF VORTEX ROTATING NW THRU ONTARIO WITH DEEPER MSTR IMPACTING THE ERN ZNS...AND 88D LOOP SHOWS SOME SCT -SHRA E OF MUNISING/ESC. BUT THESE SHRA TENDING TO WEAKEN AS THEY MOVE IN ELY FLOW ALF TOWARD WRN CWA...WHERE WV IMAGERY INDICATES MUCH DRIER AIR HAS MOVED IN ALF AND RUC ANLSYS SHOWS UPR CNVGC/DEEP LYR H85-3 QVECTOR DVGC ABV SFC HI PRES RDG AXIS. WV LOOP SUGS DRIER AIR MAKING SLOW PROGRESS EWD. H5 TEMPS OVER ENTIRE UPR GRT LKS ARE ALSO 1-3 DEGREES HIER THAN AT 12Z SUN...WITH READING AT INL UP TO -9C. OBSVD KINX 28 AT BOTH APX/GRB (VS 32/35 AT 12Z SUN) BUT DOWN TO 24 AT INL (32 AT 12Z SUN). PLENTY OF FOG/LO CLD LINGERS OVR ENTIRE FA...WITH SFC DWPTS GENERALLY ARND 60 IN LGT N FLOW TO W OF SFC LO OVR GEORGIAN BAY. FOG/ST BEGINNING TO BRK UP AFT 13Z. MAIN FCST CONCERNS TDAY REVOLVE ARND SHRA/TSRA CHCS. 09Z RUC FCST FOR UPR LO TO SHIFT GRDLY E TDAY IN GOOD AGREEMENT WITH FCSTS FM 00Z/06Z MODELS RUNS AND CONSISTENT WITH TREND OF BACK EDGE OF DEEPER MSTR SHOWN ON WV LOOP. MODEL ALSO SHOWS DEEP LYR H85-3 QVECTOR DVGC AND UPR CNVGC GRDLY OVRSPRDG ENTIRE CWA W-E AS WELL...WITH THESE NEGATIVE DYNAMICS PUSHING INTO ERY 21Z-24Z. OBSVD/FCST SDNGS INDICATE MAX TEMPS IN THE MID/UPR 70S WITH CONSIDERABLE SUNSHINE. BEST CHC FOR THESE MAX WL BE OVR THE INLAND WCNTRL...WHERE LINGERING FOG/ST SHUD BURN DURG THE LATE MRNG AS DEEPER CLD COVER ASSOCIATED WITH SHRTWV ROTATING ARND UPR LO SHUD REMAIN TO THE E. BUT EXTENSIVE CLD COVER OVR THE ERN ZNS UNDER THE DEEPER MSTR WL LIKELY INHIBIT THE TEMP RISE. MODIFIED GRB SDNG THAT WOULD BE REPRESENTATIVE FOR CNTRL ZNS FOR 76/57 SHOWS CAPE 400 J/KG. MODIFIED APX SDNG FOR WORST CASE 76/58 SHOWS CAPE 860 J/KG. BUT SINCE MAX TEMP WL LIKELY NOT REACH THIS HI OVR THE E UNDER MORE CLD COVER ...THIS INSTABILITY VALUE IS NOT LIKELY TO BE ACHIEVED. MODIFIED FCST 21Z RUC SDNG AT IWD FOR 79/58 INDICATES CAPE OF 280 J/KG...BUT WITH KINX FCST AT 22 UNDER CONSIDERABLE NEGATIVE DYNAMICS. BASED ON SDNG ANLSYS/XPCTD UPR AIR TRENDS WITH ENCROACHING NEGATIVE DYNAMICS...HAVE OPTED TO LEAVE WRN ZNS DRY WITH SOME AFTN -SHRA/ ISOLD -TSRA DVLPG OVR THE CNTRL ZNS AND -SHRA/ISOLD -TSRA OVR THE E THE ENTIRE AFTN. THIS FCST OF DCRSD CNVCTN WOULD ALSO BE CONSISTENT WITH TREND IN KINX FM YDAY... WHEN NMRS -SHRA/SCT -TSRA DVLPD OVR THE ECNTRL ZNS. KC AFDMQT FM MIDNGT SHIFT FOR LATER PDS... AFTER ANY REMAINING SHOWERS THIS EVENING...THE UPR LOW IS FAR ENOUGH EAST FOR THE ENTIRE AREA TO DRY OUT. IN FACT...THE WESTERN CWFA MAY SEE ENOUGH DRY AIR FOR IT TO CLEAR OUT. AM CONCERNED THAT THERE WILL BE FOG ONCE AGAIN...BUT WILL GO PATCHY FOR NOW SINCE IT IS UNCERTAIN IF THERE WILL BE ANY DRY ADVECTION IN THE LOW LVLS. PLUS...UPSTREAM AREAS DO NOT HAVE FOG AS BAD THIS MORNING...WHICH SUPPORTS MORE PATCHY SCENARIO FOR CWFA TONIGHT. UPPER LOW STALLS OUT AGAIN OVER ONTARIO ON TUESDAY. EVEN THOUGH THE CWFA WILL BE GENERALLY UNDER DRY NW FLOW ALOFT...AM STILL CONCERNED THAT THE EASTERN CWFA WILL HAVE ENOUGH MOISTURE TO CAUSE SOME PCPN. THIS WILL BE ESPECIALLY TRUE IF ANY SHORT WAVE ENERGY ROTATES INTO THE EAST AROUND THE UPPER LOW. PLUS...LAPSE RATES WILL BE A LITTLE STEEPER OVER THE EAST DUE TO THE CLOSER PROXIMITY TO THE LOW. SO...ANY SFC HEATING WILL CAUSE A LITTLE MORE DESTABILIZATION THAT WESTERN AREAS. SO...WILL CONTINUE WITH CHC POPS OVER THE EAST...HOWEVER WILL CUT BACK ON POPS OVER THE WEST TO ISOLATED. THE ETA AND GFS BOTH SHOW WEAK PVA LATE TUE AFTN IN RESPONSE TO S/WV ENERGY MOVING INTO THE UPR MIDWEST FROM THE NW. THE ETA IS STRONGEST WITH THE FEATURE. HOWEVER...THINK THE WEAKER GFS SOLN IS MORE REALISTIC GIVEN THE STRONG RIDGE TO THE WEST AND ANTICYCLONIC FLOW OVER THE CWFA. WITH PLENTY OF LOW LVL MOISTURE AND STEEP LOW LVL LAPSE RATES...HAVE NOT DOUBT THAT THERE WILL BE SOME CU DEVELOPMENT DURING THE DAY SO DO NOT WANT TO TOTALLY DISCOUNT SHOWERS ANYWHERE OVER THE INLAND AREAS ON TUESDAY. 1000-850MB THICKNESS VALUES RISE TO 1405 ON TUESDAY...SO IT WOULD SEEM LIKE TEMPS WILL BE A FEW DEGREES WARMER AS WELL. WILL GO WITH SOME UPR 70S OVER WI BORDER COUNTIES. NO CHANGES PLANNED TO THE WED-SUN TIME FRAME. THE ETA AND GFS BOTH SHOW SHORT WAVE ENERGY MOVING THRU THE AREA WED...MOST LIKELY CAUSING SOME DIURNAL SHOWERS AND THUNDERSTORMS AGAIN WED AFTN. OTHERWISE...WILL KEEP IT DRY UNTIL SUN AS HEIGHTS CONTINUE TO RISE WITH THE NRN PLAINS RIDGE AXIS SLOWLY SHIFTING EAST. MRD .MQT...NONE. mi AREA FORECAST DISCUSSION...RETRANSMISSION. NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 1041 AM EDT MON AUG 4 2003 SATELLITE IMAGERY THIS MORNING SHOWS LOW STRATUS AND ALTOCUMULUS BLANKETING MOST OF THE FORECAST AREA. HOWEVER...THERE IS A SMALL AREA ENCOMPASSING THE MOUNTAINS...EAST TENNESSEE...EXTREME NORTHEAST GEORGIA AND THE WESTERN MOST FOOTHILLS OF NORTH CAROLINA WITH FEW CLOUDS AND EVIDENCE THAT FOG IS BURNING OFF RAPIDLY. TRENDS SUGGEST THIS AREA WILL FILL IN QUICKLY AS UPPER CLOUDS MOVE IN FROM THE WEST. HOWEVER...THESE WILL BE THE AREAS THAT WARM UP THE MOST QUICKLY TODAY...BECOME THE MOST UNSTABLE AND PROBABLY SEE CONVECTION INITIATED FIRST; THESE AREAS WERE ALSO THE ONES INCLUDED IN THE SLIGHT RISK AREA FOR SEVERE WEATHER BY THE STORM PREDICTION CENTER. AN ACTIVE AFTERNOON AND EVENING APPEARS IN STORE FOR OUR REGION. THE MUCH-ANTICIPATED SHIFT OF THE LONGWAVE TROF POSITION FROM A LOCATION DIRECTLY WEST OF THE APPALACHIANS TO A POSITION ALONG OUR EASTERN CORRIDOR IS STILL PROGD BY THE 06Z ETA AND THE LATEST RUC BY THIS TIME TOMORROW. UPPER AIR SUPPORTS CONTINUED DESTABILIZATION ALOFT AS THE TROF SWINGS THROUGH...WITH MUCH DRIER AIR UPSTREAM DISPLAYED ON OHX SOUNDING AND QUITE EVIDENT ON THE WATER VAPOR IMAGERY. CWFA ALSO REMAINS IN A FAVORABLE POSITION WITH RESPECT TO THE RIGHT ENTRANCE REGION OF THE 30H JET PER 12Z UPPER AIR ANALYSIS. IN ADDITION TO ANY SPORADIC PRE-VORT CONVECTION THAT DEVELOPS WITH HEATING IN OUR SOUPY AIRMASS...UPPER AIR ANALYSIS SUPPORTS TWO MAIN SURGES OF CONVECTION THAT COULD SEE ORGANIZATION. ONE FOR LATE AFTERNOON AS A POTENT VORT ROUNDS THE TROF AND SHIFTS INTO THE REGION...ANOTHER FOR LATE EVENING. THE SECOND SHOT OF ENERGY MAY BE AS MUCH A WEATHER MAKER AS THE FIRST SINCE IT WILL COINCIDE CLOSELY WITH ACTUAL TROF PASSAGE OVER THE REGION...AND ENHANCE SPEED SHEAR ACROSS THE CWFA. MODIFIED SOUNDINGS FOR AFTERNOON SUPPORT CAPES OF OVER 3000 J/KG IN THE WEST...WITH LIFTED INDICES QUITE UNSTABLE. WET BULB ZEROS WILL BE MUCH LOWER TODAY WITH INFLUX OF DRY AIR ALOFT INTO THE REGION...SO STORMS WILL NOT HAVE TO GET TALL TO PRODUCE SIGNIFICANT WEATHER. EASTERN ZONES WILL...OF COURSE...HAVE DIFFICULTY REACHING FULL UNSTABLE POTENTIAL WITH LONG DELAY IN EROSION OF MORNING CLOUDS. WILL LOWER MAXES TO LOWER 80S EAST...KEEP CURRENT MAX TRENDS FOR THE SOUTH...AND RAISE MOUNTAIN MAXES INTO THE LOWER 80S. POPS WERE RAISED CWFA-WIDE TO 70 PERCENT FOR THE UPDATE. FCSTID = 44 GSP 85 68 86 69 / 70 60 30 30 AND 86 68 87 69 / 70 60 30 30 CLT 83 68 88 70 / 70 60 30 30 HKY 83 65 85 67 / 70 60 30 30 AVL 81 62 82 64 / 70 60 30 30 .GSP... GA...NONE. NC...NONE. SC...NONE. $$ BURRUS sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MEMPHIS TN 1055 AM CDT MON AUG 4 2003 RUC AND WATER VAPOR SHOW UPR TROF AXIS FROM INDIANA SOUTHWARD THROUGH THE EASTERN HALF OF THE CWFA WITH A STRONG NORTH-SOUTH UPPER LEVEL JET FROM WISCONSIN INTO THE MID SOUTH. EXPECT BEST LIFT TO BE ACROSS ERN SXNS OF THE CWFA WHERE THE LEFT EXIT REGION OF THE JET OVERLAYS THIS AFTERNOON. LOW CLOUDS ACROSS THE EASTERN HALF OF THE CWFA KEEPING TEMPS DOWN ALONG WITH INSTABILITY THIS MORNING WL BREAK UP SHORTLY. MODIFIED LZK SOUNDING INDICATES CAPES SHOULD CLIMB ABOVE 4000 J/KG WITH LIFTED INDICES OF -9C THIS AFTERNOON. BETWEEN UPPER JET...OLD BOUNDARIES AND MOIST BOUNDARY LAYER...EXPECT A CHANCE OF THUNDERSTORMS THIS AFTN. HOWEVER...SHOULD BE LESS AREAL COVERAGE THAN YESTERDAY. .MEG...NONE. SJM tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 1113 AM EDT MON AUG 4 2003 HAVE OPTED TO MAKE A MINOR UPDATE TO THE GOING ZFP FOR MOSTLY A FEW FIRST PERIOD CHANGES. STORM SYS TO CONT TO BE LOCATED TO THE NW OF THE FA TODAY. 06Z TAQ RUC SHOWS TEMPS TO GET UP INTO THE 70S-M80S TODAY WITH SOUTHERLY SFC WINDS AT 5-15 KTS. FEW TWEAKS TO FIRST PERIOD TEMPS/WINDS BASED ON THIS DATA AND CURRENT MESONET OBS. PW VALUES ACRS THE FA TO BE 1.4-1.9" TODAY AND INTO TONITE. THIS JIVES PRETTY WELL WITH AREA RAOBS AND REGIONAL GPS IPW SITES. RUC SHOWS SCT CONVECTION ACRS THE FA TODAY WITH MOCLDY SKIES OTRW. LOW-LVL MSTR TO CONT TO AFFECT THE FA TODAY AND TONITE. LOW-LVL LAPSE RATES TO BE HI ACRS NRN NY STATE TODAY. SOME MID-LVL MSTR TO AFFECT THE FA TODAY AND TONITE ALSO. BUFCAN/88D MOSAIC SHOWS SCT PCPN MOVING NORTH ACRS THE FA ATTM. NOTED FA IN SPC GEN TSTM OUTLOOK TODAY AND TONITE. CAPES TO BE AOB 2000 J/KG ACRS THE FA TODAY. ENVIRONMENT APPEARS TO BECOME MORE WEAKLY SHEARED WITH TIME ACRS THE FA TODAY AND INTO EARLY TONITE WITH WET-BULB ZERO HTS OF 12-13 KFT. WITH NO REAL MID-LVL DRY AIR AROUND TODAY...AGREE THAT THREAT FOR ANY SVR WX TODAY IS LOW. COVERAGE OF PCPN MAY BE A LIL LESS THAN CURRENT FCST INDICATES...BUT +RA A BETTER BET WITH ANY STORMS THAT DO FIRE ACRS THE FA TODAY. PREVIOUS FCST HAS THIS COVERED PRETTY WELL ALREADY. JUST A FEW COSMETIC CHANGES TO GOING ZFP FOR NOW. WRK ZONES AND FINAL ZFP ALREADY ISSUED. MURRAY PREVIOUS DISCUSSION... PERSISTENCE THE WAY TO GO AS UPPER TROF PARKED OVER THE GRTLKS WILL BE IN NO HURRY TO MOVE AS BLOCKING PATTERN RMNS OVER CONUS AND DOWNSTREAM. SO UNSETTLED WX THRU THE PERIOD WITH THREAT OF SHWRS/TSTRMS EACH DAY. DIFFICULTY WILL CONTINUE TO BE TIMING INDIVIDUAL SHRTWVS AS THEY ROTATE AROUND THE UPPER LOW. DIURNAL HEATING WL ALSO PLAY A BIG FACTOR...WITH PM/EVEN HRS LIKELY TO FEATURE THE GREATEST CHC OF RAIN EACH DAY. WITH PW'S REMAINING IN THE 1.5 - 2 INCH RANGE AT LEAST THRU MIDWEEK...THE THREAT OF LOCALLY HVY RAINS WILL CONTINUE. FLOOD POTENTIAL WL NEED TO BE MONITORED. TDY/TON: TROPICAL AIRMASS RMNS IN PLACE WITH DWPTS 70 OR HIR EXPECTED. INSTABILITY ALREADY IN PLACE. SHRTWV LIFTING OUT OF LWR OH VLY INTO NYS LATER TDY COMBINED WITH DIURNAL HEATING WILL BE ENOUGH FOR LIKELY POPS THIS PM/EVEN WITH POTENTIAL FOR HVY DOWNPOURS. HAVE GONE SLIGHTLY ABOVE TEMP GUIDANCE. TUE/WED: MODELS INDICATING THAT THE UPPER TROF WILL TAKE ON MORE OF A NEGATIVE TILT DURING THIS PERIOD AS STRONGER SHRTWV PIVOTS AROUND THE BASE OF THE TROF TON/TUE AND LIFTS NORTH TUE NITE/WED. HAVE CONTINUED WITH LIKELY POPS FOR TUES...BUT INCREASED POPS FROM CHC TO LIKELY FOR TUE NITE AND WED AS WELL. EXTENDED: NO CHANGES MADE TO PREVIOUS FCST. CHC OF SHWRS RIGHT THRU THE PERIOD AS UPPER TROF AXIS RMNS JUST TO OUR WEST. RJS .BTV...NONE. vt FLORIDA KEYS AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KEY WEST 230 PM EDT MON AUG 4 2003 CURRENT... A VERY QUIET AFTERNOON IN THE KEYS AND SURROUNDING WATERS. RUC80 ANALYSIS SHOWS A 200-300 MB ANTICYCLONIC FLOW DIRECTLY OVER THE SURFACE AREA...LIKELY SUPPRESSING SIGNIFICANT CLOUD DEVELOPMENT...LET ALONE SHOWERS AND THUNDERSTORMS. KBYX RADAR INDICATING ONLY ISOLATED ACTIVITY OVER THE SOUTHEAST GULF...WITH A SMALL CLUSTER OF SHOWERS AND ISOLATED THUNDERSTORMS NORTH OF THE CONTENT KEYS. THE REMAINDER OF KEYS AND ALL OF THE STRAITS ARE QUIET. ACTIVITY HAS FIRED OVER THE SOUTH FLORIDA MAINLAND...CONFINED TO THE GOLD COAST AND THE DEEP EVERGLADES. CONVECTION IS OCCURRING OVER NORTHWESTERN MAINLAND CUBA...MOVING NORTHWEST. WINDS OVER LAND ARE AVERAGING 150 DECREES AT JUST 5 KNOTS. C-MAN PLATFORMS ARE NEAR CALM TO BETWEEN 130-150 DEGREES AT 5 KNOTS. TEMPERATURES ARE AROUND 90 DEGREES WITH THE DEW POINT AT 77. SHORT TERM...TONIGHT THROUGH THURSDAY... IT APPEARS THE SHOWER CHANCES HAVE BEEN MARKEDLY SUPPRESSED FOR LATE THIS AFTERNOON AND THIS EVENING. THERE MAY BE AN OUTFLOW BOUNDARY THROWN OUT FROM THE WESTERN CUBAN CONVECTION THIS EVENING...BUT THE STEERING FLOW SHOULD KEEP ANY RESULTANT DEVELOPMENT TO THE WEST. PLAN TO LOWER POPS TO 20% FOR TONIGHT. THE DEEP SUBTROPICAL ATLANTIC RIDGE AXIS CURRENTLY OVER NORTH-CENTRAL FLORIDA WILL DRIFT SOUTH TO NEAR LAKE OKEECHOBEE ON TUESDAY...AND INTO THE STRAITS ON WEDNESDAY AND THURSDAY. RESULTING WINDS WILL BE LIGHT OUT OF THE EAST AND SOUTHEAST ALL THREE DAYS. CAN NOT RULE OUT A CU-LINE ON ANY OF THESE DAYS BUT NOTHING TO WARRANT GOING ABOVE CLIMO ATTM. GFS CONTINUES TO ADVERTISE AN ENCROACHMENT OF DRY AIR ALOFT ON THURSDAY. THIS MAY SUPPRESS THE CLIMO THINKING ON THURSDAY...BUT WILL LEAVE INHERITED 30% POPS ALONE FOR NOW AND SEE HOW LATER RUNS HANDLE THIS FEATURE. EXTENDED...FRIDAY THROUGH MONDAY... GFS SHOWS THE TROUGH OVER THE EASTERN USA DIGGING UNUSUALLY FAR SOUTH INTO THE NORTH-CENTRAL GULF ON FRIDAY INTO SATURDAY WITH A COOL FRONT IN THE PANHANDLE...AND SOME KIND OF PRE-FRONTAL SURFACE TROUGH OVER THE CENTRAL PENINSULA. HOWEVER...THE DEEP UPPER LEVEL ATLANTIC RIDGE HOLDS FIRM ACROSS THE BAHAMAS INTO THE SOUTHERN GULF. AT THE SURFACE...THE RIDGE AXIS MOVES NORTHWARD INTO SOUTH FLORIDA. EVEN THOUGH SURFACE WINDS TURN MORE TO THE SOUTH...AND PERHAPS SOUTHWEST BY SATURDAY...AIR ALOFT CONTINUES RATHER STABLE. SO THIS PACKAGE WILL CONTINUE WITH CLIMO POPS AND WX FOR NOW. MARINE... ATLANTIC RIDGE AXIS CURRENTLY OVER NORTH-CENTRAL FLORIDA WILL MOVE SOUTH INTO SOUTH FLORIDA TOMORROW AND INTO THE STRAITS ON WEDNESDAY AND THURSDAY. MARINE WINDS WILL BE LIGHT...AND GENERALLY FROM THE EAST AND SOUTHEAST. THE RIDGE SHIFTS BACK TO THE NORTH AND EAST ON FRIDAY AND INTO SATURDAY IN RESPONSE TO THE TROUGH OVER THE NORTHERN GULF AND WEAK FRONT OVER THE PANHANDLE. WINDS WILL BECOME MORE PRONOUNCED FROM THE SOUTHEAST ON THURSDAY...AND FROM THE SOUTH ON FRIDAY AND SATURDAY...BUT STILL BELOW CRITERIA. KEY WEST 81/91/81/91/81 20/30/30/30/30 MARATHON 81/92/81/92/81 20/30/30/30/30 .EYW...NONE. FELTGEN fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 200 PM EDT MON AUG 4 2003 RUC ANALYSIS SHOWS A STRONG VORT MOVING ACROSS NORTHERN ALABAMA WITH A LOBE OF ENERGY EXTENDING SOUTHWEST INTO SOUTHERN MISSISSIPPI. THUNDERSTORMS HAVE DEVELOPED AHEAD OF THIS FEATURE ACROSS WEST CENTRAL GEORGIA AND SOUTHEAST ALABAMA. THESE STORMS ARE BEGINNING TO INTERACT WITH THE SEA BREEZE STORMS OVER THE FLORIDA PANHANDLE. OVERALL RADAR COVERAGE AT 17Z JUSTIFIES THE LIKELY POPS IN PLACE FOR THIS AFTERNOON. MODELS: MODELS INDICATE THAT THE CLOSED UPPER LOW OVER THE GREAT LAKES REGION WILL LIFT SLOWLY TO THE NORTHEAST TROUGH THE SHORT TERM PERIOD. HOWEVER...A SERIES OF IMPULSES ROUNDING THE BASE OF THE LONG WAVE TROUGH ALONG WITH THE RIDGE BUILDING OUT WEST WILL FURTHER AMPLIFY THE UPPER LEVEL PATTERN. ONE SUCH IMPULSE IS CURRENTLY OVER NEBRASKA AS SHOWN BY THE LATEST RUC ANALYSIS. THE GFS HAS THE BEST HANDLE ON THIS AS OF 18Z. THE GFS STRENGTHENS THIS VORT AS IT DROPS TO THE SOUTHEAST INTO NORTHERN ARKANSAS OVERNIGHT AND THEN TAKES IT ON A COLLISION COURSE WITH MY CWA LATE TUESDAY AND EARLY WEDNESDAY. THE ETA SOLUTION IS WEAKER WITH MOST OF ITS ENERGY DISPERSING NORTH OF MY FA LATE TUESDAY/WEDNESDAY MORNING. THE DIGGING TROUGH WILL PUSH A COLD FRONT INTO THE SOUTHEAST AND BY THURSDAY AFTERNOON SHOULD LIE ACROSS CENTRAL GA AND AL. DEEP LAYER MOISTURE WILL REMAIN IN PLACE PER FORECAST MODEL SOUNDINGS SHOWING AFTERNOON PWATS NEAR 2.00". ZFP: MEAN 1000 TO 700MB FLOW WILL BE SIMILAR TO TODAY (WEST TO SOUTHWEST 10 TO 15 KNOTS) WHICH IS OUR WETTEST PATTERN FOR SEA BREEZE THUNDERSTORMS. IN ADDITION...THE AFOREMENTIONED SHORT WAVE ENERGY TRANSLATING THE BASE OF THE TROUGH AND THE APPROACHING COLD FRONT LATE WEEK COULD RESULT IN A FEW DISTURBED DAYS. WILL PLACE LIKELY POPS ACROSS THE BOARD FOR TUESDAY AND WEDNESDAY WITH GOOD CHANCE ON THURSDAY. SLIGHT/LOWER END CHANCE POPS FOR NIGHTTIME PERIODS. .MARINE...WEST TO SOUTHWEST WINDS WILL CONTINUE WITH SPEEDS BELOW SCEC CRITERIA. SEE NO REASON TO SPLIT ZONES SO WILL MAINTAIN ONE GROUPING. .FIRE WX...RH VALUES REMAIN UP. NO CONCERNS. EXTENDED...FRIDAY THROUGH MONDAY...THE MRF SHOWS A VERY DEEP UPPER LEVEL TROUGH OVER THE EASTERN U.S. WITH THE MRF CLOSING OFF A LOW CENTERED ACROSS THE OHIO VALLEY SATURDAY THROUGH MONDAY. AT THE SURFACE...LOW PRESSURE IS FORECAST TO FORM ON THE FRONT ACROSS SOUTHERN GEORGIA SATURDAY AND LIFT TO THE NORTHEAST WHICH DRAGS THE FRONT THROUGH MY CWA. THIS IS NOT THE FIRST TIME WE HAVE SEEN THE MRF WANTING TO PUSH A FRONT ACROSS THIS SUMMER AND I AM RELUCTANT TO ACCEPT. HOWEVER...THE EXTENDED GFS TIME HEIGHT CROSS SECTIONS DO SHOW A MUCH DRIER AIRMASS FILTERING IN ABOVE 700 MB FRIDAY NIGHT AND THE MRF CONTINUES THIS TREND THROUGH MONDAY. WILL SHOW A POP GRADIENT OF 20% NORTHWEST TO 50% SOUTHEAST ON FRIDAY...THEN ONLY SLIGHT POPS FOR THE REMAINDER OF THE PERIOD. .PRELIMINARY POINT TEMPS/POPS... TLH 73 91 73 89/ 20 60 30 60 PFN 76 88 76 87/ 20 60 30 60 DHN 73 89 73 88/ 20 60 30 60 ABY 73 89 73 88/ 30 60 30 60 VLD 72 92 72 90/ 30 60 30 60 CTY 73 90 73 89/ 20 60 30 60 .TLH WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...NONE. BARRY PREVIOUS DISCUSSION: ******************************************************************** THIS MORNINGS MODIFIED SOUNDING WITH A MAXIMUM TEMPERATURE OF 88 DEGREES GENERATED ABOUT 3015 J/KG. PRECIPITABLE WATER IS 1.87 INCHES. DESPITE THE NEGATIVE VORTICITY PROMISED BY THE MESO ETA ALONG THE FLORIDA...ALABAMA..GEORGIA STATE LINE...IT LOOKS LIKE THE SEABREEZE REGIME IS TAKING OVER WITH A TYPE 5 DAY WITH MODERATE WESTERLY UNIFORM FLOW IN THE VERTICAL. LINES OF THUNDERSTORMS ARE ALREADY POPPING IN THE EASTERN PANHANDLE... AND NEW LINES OF THUNDERSTORMS ARE FORMING AHEAD OF THOSE JUST EAST OF THE APALACHICOLA RIVER RIGHT IN LINE WITH TYPE 5 CLIMATOLOGY. 60 PERCENT POPS ACROSS THE BOARD OVER THE ENTIRE TLH AREA IS STILL GOOD...ESPECIALLY SINCE THE NORTHERN FRINGES OF OUR AREA WILL BE AFFECTED BY THE STRONGER POSITIVE VORTICITY EXPECTED THERE. SOME LINES OF SHOWERS ARE ALREADY ENTERING COFFEE COUNTY FROM COVINGTON COUNTY. IT'S GOING TO BE ANOTHER WET DAY.... LANIER PREVIOUS DISCUSSION: ******************************************************************** CURRENTLY ISOLATED SHOWERS DRIFT EAST ACROSS THE COASTAL WATERS AND PORTIONS OF THE BIG BEND AND PANHANDLE. AREAS OF RAIN HAVE DISSIPATED OVER GA LEAVING SOME MID AND HIGH CLOUDS. THROUGHOUT THE CWA LIGHT TO CALM WINDS AND MILD TEMPS PERSIST. SHORT TERM FORECAST REMAINS THE SAME...H5 LOW REMAINS PARKED OVER THE WESTERN GREAT LAKES WITH THE TROF BASE JUST NORTH OF THE AREA. ON THE SURFACE...THE BERMUDA HIGH RIDGE AXIS IS SITUATED THROUGH CENTRAL FLA INTO THE CENTRAL GULF. THE MEAN FLOW WILL PICK UP SOME TODAY AND TUESDAY...SO, LOOKING AT A TYPE 5 DAY WITH W-SW FLOW GREATER THAN 10 KTS...THIS WOULD FAVOR HIGHER POPS IN THE FL AND AL ZONES. PLANNING ON MESHING THE AVG GUIDANCE...SEABREEZE CLIMO AND SURROUNDING OFFICES FX, COMING UP WITH 60 POPS TODAY FOR ALL ZONES. THEN BACK TO THE USUAL 50% UNTIL THE END OF THE WEEK. GFS IS HINTING AT GETTING SOME DRIER AIR INTO THE SE AS A LOW IS PROGGED TO MAKE ITS WAY ACROSS THE CENTRAL US AND DRAG A FRONT INTO THE CWA THURS/FRI. STILL HOLDING ONTO CHANCE POPS BUT LOWER THAN 50 FOR NE ZONES. TEMPS REMAIN JUST NEAR CLIMO FOR THE NEXT FEW DAYS. BUT AS SEEN FROM THE PAST FEW DAYS...IT IS POSSIBLE FOR RAIN PLAGUED AREAS TO REMAIN IN THE MID 80S FOR HIGHS. OVER NIGHT TEMPS WILL CONTINUE TO BE MUGGY WITH MIN TEMPS IN THE MID TO LOW 70S. .MARINE...WINDS SHOULD PICK UP TO THE 10 TO 15 KT RANGE LATE WED AND A TAD MORE WESTERLY AS ABOVE MENTIONED FRONT APPROACHES MARINE AREA. .FIRE WX...NO CONCERNS .EXTENDED...AS MENTIONED ABOVE...LOWERED POPS A TAD AT THE END OF THE WEEK FOR NE ZONES (AL AND N GA). $$ BOLINSKI fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 220 PM EST MON AUG 4 2003 PUBLIC FORECAST DISCUSSION FOR 330 PM EST ISSUANCE... UPPER LEVEL LOW AND TROF WILL CONTINUE OVER THE AREA THROUGH WEDNESDAY. EXPECT MAINLY DIURNAL AFTERNOON/EARLY EVENING CONVECTION NEXT COUPLE OF DAYS. NCEP MODEL OUTPUT (MOS) CONTINUES TO UNDERESTIMATE COVERAGE WITH THIS PATTERN...ALTHOUGH SOME WEAK WARM AIR ADVECTION AT MID LEVELS SHOULD HELP INHIBIT CONVECTION TUESDAY...ESPECIALLY OVER WESTERN AREAS. WILL KEEP RELATIVELY SMALL DIURNAL RANGES WITH AFTERNOON CONVECTION ALONG WITH LOW CLOUDS OVERNIGHT. ONLY MINOR CHANGES MADE TO ONGOING FORECAST. EXTENDED DISCUSSION... NO MAJOR CHANGES PLANNED FOR DAYS 4-7. UPPER LEVEL TROF WILL CONTINUE TO PERSIST OVER THE EASTERN US BUT MAIN SFC FRONTAL BOUNDARY PROGGED BY MEDIUM RANGE MODELS TO REMAIN ALONG THE MID-ATLANTIC REGION AND ALLOW WEAK SFC RIDGING TO BUILD IN OVER THE GREAT LAKES REGION SO WILL CONTINUE WITH DRY FCST. NOT READY TO BITE ON STRENGTH OF COLD AIR OFFERED BY GFS BUT WILL NUDGE TEMPS DOWN JUST A DEGREE OR TWO FROM CURRENT FCST TOWARD ECMWF SOLN. AVIATION DISCUSSION FOR 12Z... MAIN CHANGE WAS TO ADD VCTS AT KSBN AND HIT TSRA HARDER WITH TEMPO GROUP AT KFWA. ELONGATED SHORTWAVE AND ASSOCIATED 5H COLD POOL ROTATING THROUGH IN/IL BORDER AREA AND WILL GIVE DECENT SHOT OF PVA/LIFT TO KFWA AREA BY ABOUT 18Z. MEANWHILE RUC40 SOUNDINGS INDICATE MODERATE INSTABILITY WITH SURFACE BASED CAPES 2500-3000 J/KG AT KFWA AND LESSER AROUND 1800 J/KG AT KSBN. PROXIMITY OF WEAK SURFACE TROF SHOULD ALSO ASSIST IN INITIATING DEEP MOIST CONVECTION FAIRLY EARLY THIS AFTERNOON. HAVE TRIED TO KEY ON BEST TIMING WITH 3 HOUR PERIOD OF VCTS AT KSBN 18Z-22Z AND TEMPO AT KFWA 19Z-22Z. NEXT AVIATION FORECAST PROBLEM WILL BE FOG/ST DEVELOPING AS TOP OF MOIST BOUNDARY LAYER COOLS...HAVE FORECAST DOWN TO CRITICAL 2SM BR CIGS 006 FOR NOW...SUSPECT THAT KFWA COULD GO LIFR 10Z-12Z ESPECIALLY IF AIRPORT HIT WITH DECENT RAINFALL TODAY...HOWEVER WILL LET THIS DETAIL EVOLVE IN FUTURE FORECASTS IF DEEMED MORE LIKELY. PBM .IWX... IN...NONE. MI...NONE. OH...NONE. $$ SKIP/JAL in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 205 PM EDT MON AUG 4 2003 .SHORT TERM (DAYS 0-3)... SCT TSRA DEVELOPING ALONG I-65 CORRIDOR ATTM JUST AHEAD OF 500MB TROF AXIS AND WITHIN LFQ REGION OF UPSTREAM 300MB JET CORE. WITH LOWER FREEZING LEVELS WITHIN MID-LEVEL TROF AXIS, REPORTS OF COPIOUS SMALL HAIL BEING RECEIVED OUT OF CURRENT CELLS. WILL HAVE TO WATCH FOR POTL SVR HAILERS AS THE AFTERNOON WEARS ON. A RATHER COMPLEX & UNCERTAIN FORECAST DURING THIS PERIOD, REVOLVING AROUND MEAN ERN CONUS TROF AND NWLY FLOW ALOFT OVER LMK FA. PER 15Z RUC, TROF AXIS SWINGS EWD THIS EVE WITH ATTENDANT SFC TROF MEANDERING SWD THRU FA. BEST CHCS FOR PCPN LOOK TO ALSO MOVE SEWD ASSOC WITH SFC TROF AND JET STREAK MVMTS. THEN INTO TUE-WED TIMEFRAME, SFC TROF SETTLES INTO SRN KY VICINITY. GFS DEVELOPS STG MCS ACROSS CEN/SRN PLAINS TONIGHT. RESULTING MCV ACTS TO SLOW SFC TROF MVNT WITH A MORE NWD PLACEMENT ACROSS CEN KY TUE-WED. WILL LEAN TWDS ETA SOLN FOR NOW. ONE LMTG FACTOR FOR PCPN TUE-WED IS A POOL OF LOWER 850-500MB L/R'S NOW OVER MN/IA MOVES INTO OH VLY REGION DURING THIS PERIOD. OVERALL, IT APPEARS BEST CHCS FOR TSRA TUE-WED LOOK TO BE ACROSS SRN 1/2 OF FA, CLOSER TO SFC TROF AND SLIGHTLY BETTER INSTABILITY AND PWS. CONVERSELY, PER MAV/MET MOS TRENDS, CHCS FOR PCPN LOOK RELATIVELY LOW ACROSS NRN 1/2 OF FA. YET ANOTHER 500MB TROF DEVELOPS OVER FA BY THU, PER GFS. MID-LEVEL INSTABILITIES DO INCREASE SOMEWHAT, SO ISO PCPN NOT OUT OF THE QUESTION, ESP OVER ERN ZONES. HWVR, LOOKS LIKE MOST OF THE MID-LEVEL WAVES WILL REMAIN S OF THE FA, WHICH WOULD LIMIT ORGANIZED PCPN CHCS. XXV .EXTENDED PERIOD (DAYS 4-7)... CENTRAL KENTUCKY AND SOUTHERN INDIANA LOOK TO BE JUST WEST OF THE PATH OF ENERGY ALONG UPPER LEVEL TROUGH AXIS. ALTHOUGH MODELS ARE GENERATING SOME DIURNALLY DRIVEN CONVECTION ALONG OUR EASTERN PERIPHERY DURING THE FRIDAY TO MONDAY TIMEFRAME...WILL CONTINUE A DRY FORECAST. EXTENDED TEMPS LOOK TO BE A LITTLE COOLER AS UPPER TROUGH BECOMES REDEFINED AND HIGHER AMPLIFIED IN THE VICINITY. STRONG RIDGE SHOULD HOLD WELL TO THE WEST OVER THE PLAINS AND MISSOURI VALLEY SO THAT TEMPS WILL CONTINUE TO BE A LITTLE BELOW NORMAL ACROSS THE LOWER OHIO VLY. JMB .LMK...NONE. ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 440 PM EDT MON AUG 4 2003 MAIN FCST CONCERNS INCLUDE SHRA/TSRA TRENDS INTO WED. WV IMAGERY AND RUC ANALYSIS INDICATED ELONGATED H5 LOW FROM NE ONTARIO INTO IN AND A BROAD RDG OVER THE WRN CONUS. ONE VORT ON THE NRN END OF THE TROF WAS LOCATED NEAR CYTS WHILE SRN VORT WAS MOVING INTO SRN OH. CONFLUENT MID/UPR LVL FLOW NEAR WRN LK SUPERIOR ON AND UPR LVL CONV WITH LEFT ENTRANCE OF H25 JET HAS AIDED BUILDING SFC RDG...CLEARING AND HAS SUPPRESSED DIURNAL SHRA. 12Z KINL/KMPX SNDGS INDICATED DRIER LOW LVL PRFL AND BUILDING SUBSIDENCE INVERSION WITH 600-700 MB WARMING. FARTHER EAST...DEEPER MOISTURE AND UPR LVL SUPPORT WITH QVECTOR CONV CLOSER TO ONTARIO VORTEX...SUPPORTED BATCH OF SHRA/TSRA FROM NEAR WAWA TO THE SAULT. STABILIZING NRLY FLOW OFF OF LK SUPERIOR HAS SUPPRESSED SHRA OVER MUCH OF UPR MI EXCEPT OVER THE SOUTH WHERE SCT SHRA/TSRA HAD DEVELOPED NEAR KIMT. SLIGHT MDL DIFFERENCES ARISE IN HANDLING EVOLUTION OF H5 AFTER 24 HRS SHOULD HAVE MINIMAL IMPACT ON SENSIBLE WEATHER FOR THE WRN LAKES. HOWEVER...THE ETA WITH ITS MORE ELONGATED TROF RETAINS WEAK QVECTOR CONV AND A MORE MOIST PRFL OVER THE ERN CWA THAN THE ETA/GFS FROM LATE TUE INTO WED. HAVE GENERALLY SIDED WITH THE GFS THE GFS WHICH IS SUPPORTED BY THE UKMET AND CAN GLBL. TONIGHT...CURRENT RADAR/SAT TRENDS SUGGEST SCT SHRA/TSRA WILL REMAIN CONFINED TO S CNTRL UPR MI DURING THE EARLY EVENING AS NRLY FLOW OFF OF LK SUPERIOR CONTINUES. THE ERN CWA ALSO REMAINS IN CLOSE ENOUGH PROXIMITY TO ONGOING CONVECTION...DEEPER MOISTURE AND BETTER QG FORCING TO RETAIN POSSIBILITY FOR ISOLD SHRA/TSRA THIS EVENING. ADDITIONAL ISOLD SHRA MAY ALSO MOVE IN OVERNIGHT AS MOISTURE/SHRA SPIN AROUND NE ONTARIO VORTEX. FARTHER WEST 700-300 QDIV AND UPR LVL CONFLUENCE WILL DOMINATE...PER ETA AND RUC. WHILE SOME LOW LVL DRYING/MIXING HAS OCCURRED DEWPOINTS REMAINED IN THE LOWER 60S. WITH WEAK GRADIENT AND BNDRY LYR WINDS FCST BLO 10 KTS OVERNIGHT...EXPECT AREAS OF FOG TO FORM AGAIN WHICH SHOULD BE THICKEST WHERE RAINFALL HAS OCCURRED THIS AFTERNOON NEAR KIMT. TUE INTO WED...WHILE SYNOPTIC ENVIRONMENT BECOMES LESS FAVORABLE FOR SHRA/TSRA DEVELOPMENT WITH CONTINUED UPR LVL CONFLUENCE AND SUBSIDENCE...CANNOT RULE OUT SOME DIURNAL CONVECTION. MODIFIED ETA SNDGS WITH (MID TO UPPER 70S WITH DEWPOINTS IN THE LOWERS 60S) STILL GIVE CAPE VALUES IN THE 400-800 J/KG RANGE EACH AFTERNOON. INCREASING 750-600 MB WARMING WITH SUBSIDENCE INVERSION WILL BE A NEGATIVE FACTOR. BEST CHANCE TO TRIGGER ANY CONVECTION WILL BE ALONG LK BREEZE FRONTS OVER INLAND PORTIONS OF WEST AND CNTRL CWA AND SHOULD BE DISPLACED TOWARD THE LK MI SIDE IN THE ERN CWA GIVEN 10-15 KT BNDRY LYR NW FLOW. MDL DIFFERENCES INCREASE UNCERTAINTY WED WITH LOW LVL WIND FIELD AND LIKELY LOCATION OF LK BREEZE BOUNDARIES. SO...HAVE AGAIN GONE WITH ISOLD SHRA/TSRA MAINLY WELL INLAND FROM LK SUPERIOR. THU...WHILE THE ETA FCST SNDGS INDICATE SOME INLAND CAPE AGAIN... HAVE LEFT PCPN OUT AS GFS SHOWS RDG AND SUBSIDENCE BUILDING IN MORE PROMINENTLY THAN THE ETA WITH SIGNIFICANTLY DRIER ACYC NRLY LOW LVL FLOW. FRI-MON...MDLS REMAIN CONSISTENT WITH PERSISTENT HIGH AMPLITUDE PATTERN CONSISTING OF AN EPAC CLOSED LOW...SRN ROCKIES TO NRN PLAINS RDG AND A TROF OVER THE ERN CONUS. GFS HAS TRENDED STRONGER AND TOWARD A SLIGHT RETROGRADE MOTION WITH THE TROF OVER THE EAST WITH A CLOSED LOW REDEVELOPING WHILE THE ECMWF/UKMET/CANADIAN WERE MORE CONSISTENT WITH PREVIOUS RUNS. THIS WILL LEAVE UPR MI IN A RELATIVELY DRY NNW FLOW PATTERN AS LITTLE ADDITIONAL MOISTURE MOVES INTO THE REGION. BEST CHANCE FOR ANY PCPN WOULD BE WITH WEAK SHRTWVS SLIDING DOWN THE RDG. WHILE THERE IS CONSIDERABLE UNCERTAINTY WITH PLACEMENT AND TIMING OF SUCH FEATURES...ECMWF/UKMET/GFS SUGGEST THIS WOULD BE MORE LIKELY SUN. SO...MARGINAL SHRA/TSRA CHANCE WAS LEFT IN FOR SUN OVER THE WEST HLF OF UPR MI WHICH IS IN CLOSER PROXIMITY TO MOISTURE/INSTABILITY BUILDING OVER THE NRN PLAINS INTO THE UPR MS VALLEY. H8 TEMPS NEAR 12C WOULD GIVE SEASONAL INLAND READINGS IN THE MID TO UPPER 70S WITH SLIGHTLY LOWER READINGS NEAR LK SUPERIOR WITH WEAK NRLY FLOW OR LK BREEZES. .MQT...NONE. JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 300 PM CDT MON AUG 4 2003 CONVECTION IS GETTING A LITTLE SLOWER START ACROSS OUR AREA THIS AFTERNOON BUT LATEST LOOK AT THE RADAR INDICATES SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING OVER CENTRAL MISSISSIPPI. EXPECT CONVECTION TO CONTINUE INTO THE EVENING AS OUR MOIST AIRMASS CONTINUES TO DESTABILIZE THE REMAINDER OF THE AFTERNOON. LATEST 300MB RUC ANALYSIS HAS THE NOSE OF A JET STREAK MOVING INTO NRN MISSISSIPPI WHICH WILL AID THE DEVELOPMENT OF SEVERE STORMS THIS AFTN ACROSS NRN MISSISSIPPI. THE THREAT FOR SEVERE THUNDERSTORMS SHOULD REMAIN MORE ISOLATED OVER OUR AREA. REFER TO OUR HWO FOR ADDITIONAL INFORMATION CONCERNING THE POTENTIAL FOR SEVERE WX. MODELS AGREE THAT THE UPPER TROUGH OVER THE ERN CONUS WILL DRIFT EAST THROUGH WEDNESDAY AS THE CLOSED UPPER LOW OVER THE GREAT LAKES REGION LIFTS TO THE NORTHEAST. THEY ALSO PEG A SHORTWAVE MOVING ACROSS OUR AREA TUESDAY. DIFFERENCES OCCUR AT THE SURFACE AND THE EVOLUTION OF A LOW PRESSURE CENTER THAT THE GFS MOVES RAPIDLY EAST TUESDAY NIGHT WITH A TRAILING COLD FRONT INTO NRN MISSISSIPPI. WL DOWNPLAY THE LOW BUT GO WITH A GENERAL TROUGH THAT WL RESULT IN CONTINUED HIGHER POPS ACROSS OUR NRN COUNTIES THROUGH WEDNESDAY. THE GFS PROGGS A STRONGER SHORTWAVE SLIDING SOUTH OVER OUR AREA LATE THURSDAY THAT WILL DEEPEN THE UPPER TROUGH OVER US AND DRIVE THE WEAK SFC TROUGH TO THE SOUTH INTO OUR AREA. EXTENDED: FRI-MON THIS WEAK TROUGH WILL DRIFT SOUTH THROUGH THE AREA FRIDAY. THE GFS PUSHES THE TROUGH TO THE COAST BY FRIDAY MORNING BUT WL OPT FOR A SLOWER MOVEMENT AND HOLD POPS IN FOR THE WHOLE AREA FRIDAY. DRIER AIR WILL FILTER INTO THE REGION BEHIND THE TROUGH WITH DEW PT TEMPERATURES LOWERING INTO THE MID 60S ACROSS OUR NORTHERN ZONES AND UPPER 60S SOUTH. ANOTHER SHORTWAVE WILL MOVE ACROSS THE AREA SATURDAY BUT MOISTURE IS EXPECTED TO BE LIMITED AND WL LEAVE OUT MENTION OF POPS FOR NOW. THE DRY TREND WILL LAST THROUGH SUNDAY. YET ANOTHER SHORTWAVE WILL DROP SOUTH OVER THE AREA MONDAY. THIS SHORTWAVE WILL TAKE A MORE SOUTHERLY TRACK OVER THE ARKLATEX REGION. ENOUGH MOISTURE IS EXPECTED TO BE AVAILABLE TO DEVELOP A FEW STORMS OVER OUR SE ARKANSAS COUNTIES AND LOUISIANA PARISHES SO HAVE INTRODUCED SLGT CHC POPS IN FOR MONDAY AFTN OVER THE WESTERN PORTION OF THE CWA. PRELIM NUMBERS... JAN BB 072/090 072/090 072 22342 BBBBB 092/071 092/071 093/070 092/070 090 44332211102 MEI BB 071/090 071/090 070 22343 BBBBB 092/070 092/068 093/067 092/068 091 43332211101 $$ 22 ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE AMARILLO TX 243 PM CDT MON AUG 4 2003 ISOLATED CONVECTION DEVELOPING JUST OUTSIDE THE WINDOW OVER EASTERN AND CENTRAL CARSON COUNTY. AMA HAS REACHED A RECORD MAX OF 103 THIS AFTERNOON. MID LEVEL MOISTURE PLUME SHOWS UP WELL ON WATER VAPOR IMAGERY. WILL RAISE POPS TO 40S NORTH AND 30S SOUTH FOR TONIGHT. CENTER OF 595 DM RIDGE LOCATED OVER SOUTHEAST NM PER LATEST RUC. MINOR SURFACE LOW NOW OVER THE NORTHERN ZONES WITH WEAKLY FORCED BOUNDARY FROM PERRYTON TO DALHART. INSTABILITY INCREASES NORTH OF THE BOUNDARY WITH LAPSE DATA SUGGESTING CAPE VALUES AROUND 2000 J/KG AND LI/S TO MINUS 6 DEGREES. HAVE ALSO WARMED MINS TONIGHT FOR MOST LOCATIONS BASED ON PERSISTENCE. CONSENSUS FORM GFS/EUROPEAN AND CLIMATOLOGY SUGGESTS WEAK/MINOR SHORTWAVES WILL PROPAGATE OVER AND THROUGH THE SOUTHERN ROCKIES RIDGE SIMILAR TO THE PAST FEW DAYS. TIMING THE WAVES WILL BE THE PRIMARY FORECAST CHALLENGE THIS WEEK. HAVE INTRODUCED NIGHTTIME 20 POPS TO THE CLIMATOLOGICALLY FAVORED NORTHWEST ZONES WEDNESDAY AND THURSDAY. INTRODUCED 20 POPS CENTRAL AND WEST FOR SUNDAY AFTERNOON/NIGHT BUT LEFT FRIDAY AND SATURDAY DRY AND CONTINUED WARM/HOT FOR NOW. FCSTID = SLATTERY AMARILLO 72 96 66 96 / 30 20 20 10 BEAVER 72 96 68 99 / 40 20 20 10 BOISE CITY 67 94 62 95 / 40 20 20 10 BORGER 70 97 70 99 / 30 20 20 10 BOYS RANCH 68 97 68 99 / 30 20 20 10 CANYON 72 95 67 96 / 30 20 20 10 CLARENDON 73 98 69 98 / 30 20 20 10 DALHART 67 95 65 95 / 40 20 20 10 GUYMON 69 95 68 99 / 40 20 20 10 HEREFORD 71 98 67 96 / 30 20 20 10 LIPSCOMB 72 95 69 97 / 40 20 20 10 PAMPA 71 97 69 96 / 30 20 20 10 SHAMROCK 73 97 70 97 / 30 20 20 10 WELLINGTON 73 96 72 97 / 30 20 20 10 .AMA... TX...NONE. OK...NONE. $$ tx