AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LITTLE ROCK AR 230 PM CDT WED AUG 4 2004 .DISCUSSION... HIGH LVL CLOUDS HAVE HELD AFTN TEMPS A FEW DEGREES LOWER THAN FCST. HOWEVER...SFC DEWPOINTS IN THE MID AND UPPER 70S ARE PRODUCING HEAT INDICES AROUND ADVY CRITERIA. WILL LET ADVY EXPIRE WITH THIS FCST ISSUANCE. LATEST SFC DATA SHOWS CDFNT EXTENDS FROM SWRN MO BACK INTO NWRN OK. BNDRY HAS BEEN MOVING A BIT SLOWER THAN PROGS INDCD BUT EXPECT IT TO SPEED UP THIS EVENING AND WORK INTO NWRN AR. AREA RADARS ARE QUIET ATTM...BUT LATEST RUC STILL SHOWING SCTD SHRA/TSRA FORMING BY THIS EVENING ALONG THE FNT AS UPPER SUPPORT ARRIVES AND CAP ERRODES. MENTIONED SCTD POPS TNGT ALONG AND AHEAD OF CDFNT. LEFT SOME LINGERING SLIGHT CHC POPS IN FOR SERN AR THU MRNG ALONG DEPARTING FNT. OTHERWISE...MUCH DRIER AIR WILL GRADUALLY FILTER IN ON NWLY WINDS THU AFTN AND NIGHT. MODELS STILL IN GOOD AGREEMENT WITH OVERALL TRENDS IN THE LATER PDS. UPPER HIGH WILL CONT TO RETROGRADE WWD AND A SIG UPPER TROF WILL FORM OVER THE ERN PART OF THE NATION. RESULTANT NWLY FLOW ALOFT ACRS AR WILL PUSH LATEST CDFNT WELL S OF THE FA BY LATE IN THE WEEK. BLO NORMAL TEMPS AND MUCH DRIER AIR WILL MOVE IN BEHIND FROPA AND PERSIST INTO SAT. SFC HIGH PRES SLIPS E OF THE FA OVER THE WEEKEND...ALLOWING RETURN FLOW TO SET UP AND A RETURN TO MORE NORMAL TEMPS. NWLY FLOW ALOFT WILL PREVAIL BUT LITTLE IN THE WAY OF UPPER ENERGY TO SUPPORT RAIN CHCS INTO EARLY NEXT WEEK. THE NEXT CDFNT IS PROGGED TO AFFECT AR TUE AND WED...WHICH AGAIN IS A LITTLE SLOWER THAN YESTERDAY/S DATA INDCD. HAVE PLACED CHC POPS IN FOR DAY 6 AND 7 WITH FROPA. GOING FCST TEMP TRENDS IN THE EXTENDED LOOK GOOD AND NO SIG CHGS MADE. && .LZK WATCHES/WARNINGS/ADVISORIES...NONE. && $$ 44 ar AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 157 PM MDT WED AUG 4 2004 .SHORT TERM (TONIGHT THROUGH THURSDAY NIGHT)... ANOTHER WAVE OF MONSOONAL CLOUDS AND TSTMS EVIDENT ON SATELLITE AND IN RUC OVER SOUTHERN AZ. VORT MAX ASSOCIATED WITH THIS SURGE APPEARS WELL PROGGED BY MAINLINE MODELS. LEADING EDGE OF PLUME OUGHT TO SPREAD ACROSS CWA FROM SW TO NE LATER THIS EVENING. HAVE INCREASED POPS OVER SE UT AND SW CO THIS EVENING AND AGAIN OVERNIGHT THRU NOON THU NOON. MOISTURE PLUME CONTINUES TO SPREAD NORTHWARD THU AFTERNOON. WILL STAY WITH CURRENT FORECAST POPS...AS CLOUD COVER MAY INHIBIT SURFACE HEATING AND TSTM DEVELOPMENT. TEMP AND POP GUIDANCE FOR TONIGHT AND THU SHOW LESS DIFFERENCE BETWEEN MODELS THAN PREVIOUS MODEL RUNS. CURRENT POPS SEEMED REASONABLE...WITH COOLER TEMPS THU AS WELL. .LONG TERM (FRIDAY THROUGH WEDNESDAY)...THE UPPER LEVEL RIDGE OVER WEST TEXAS WILL BE SHIFTING WEST THROUGH THE EXTENDED PERIOD...WITH ALL MEDIUM RANGE MODELS IN GOOD AGREEMENT WITH THIS SOLUTION. EXPECT A GRADUAL DRYING TREND TO TAKE PLACE ACROSS THE FORECAST AREA AS OUR FLOW ALOFT SWINGS BACK AROUND TO THE NORTHWEST BY EARLY NEXT WEEK. FRIDAY...REMNANT LOW LEVEL MOISTURE FROM THURSDAY SYSTEM WILL ALLOW DIURNALLY DRIVEN CONVECTION TO FIRE...ESPECIALLY OVER THE HIGHER TERRAIN. LESS CLOUD COVER AND SLIGHT WARMING ALOFT WL ALLOW SFC TEMPS TO REBOUND FROM THE COOLER THURSDAY READINGS. SATURDAY...FLOW ALOFT BECOMES MORE WESTERLY WITH THE RIDGE SHIFTING/REBUILDING OVER THE WESTERN U.S. AS SHRTWV ENERGY SWINGS EAST THROUGH THE NRN ROCKIES. CURRENT GFS IS INDICATING THE NRN STREAM ENERGY WL BE FAIRLY ACTIVE...AND HAVE BOOSTED POPS OVER THE NRN ZONES AS TRAILING WAVE LKLY TO ENHANCE CONVECTION BY SATURDAY AFTERNOON. LITTLE CHANGE IN TEMPS FROM THOSE SEEN ON FRIDAY. SUNDAY THROUGH WEDNESDAY...DRIER...NORTHWEST FLOW ALOFT WL PERSIST THROUGH THE PERIOD WITH DIURNALLY DRIVEN CONVECTION CONFINED TO ALONG THE DIVIDE IN WESTERN COLORADO...WITH A FEW STORMS ALSO POSSIBLE OVER THE HIGHER MTNS OF EASTERN UTAH. TEMPS ARE EXPECTED TO REMAIN FAIRLY PERSISTENT THROUGH THE PERIOD WITH READINGS HOLDING NEAR SEASONAL NORMS. && .GJT WATCHES/WARNINGS/ADVISORIES... .CO...NONE. .UT...NONE. $$ CJC/JDC co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1150 AM CDT WED AUG 4 2004 .DISCUSSION... UPDATED THE FORECAST TO REMOVE MORNING WORDING AND INCREASE RAIN CHANCES TO LIKELY CATEGORY THIS AFTERNOON AROUND SPRINGFIELD AND JACKSONVILLE. STILL RATHER HUMID THIS AFTERNOON WITH HIGHS IN THE 80S WITH WARMEST READINGS OVER SE IL. LATEST SURFACE ANALYSIS HAS A FRONTAL BOUNDARY OVER NORTHERN INDIANA INTO CENTRAL IL ALONG I-72 AND ACROSS NORTHERN MO TO 1009 MB LOW PRESSURE EAST OF KANSAS CITY. AREA OF CONVECTION AHEAD OF THIS LOW OVER NE MO AND MOVING ESE INTO WESTCENTRAL IL FROM QUINCY SOUTH TO SAINT LOUIS. ANOTHER AREA OF CONVECTION EAST OF IL OVER SE INDIANA AND MOVING AWAY FROM IL. ALSO SOME SHOWERS OVER NORTHERN IL MOVING SOUTH WITH ANOTHER FRONTAL BOUNDARY CLOSE TO I-80 WITH DRIER AND COOLER CANADIAN AIR NORTH OF I-80 FILTERING SOUTH FROM 1028 MB HIGH PRESSURE OVER NORTHERN LAKE WINNIPEG. NOON TEMPS RANGE FROM MID 70S FROM PEORIA NW TO MID 80S SE IL. STILL MUGGY WITH DEWPOINTS IN THE UPPER 60S TO AROUND 70...EVEN UPPER 70S FAR SE AT LAWRENCEVILLE. LOW PRESSURE TO MOVE ESE ALONG FRONT THAT SAGS SOUTH FROM I-72 TOWARD I-70 BEFORE 00Z AND PAST LAWENCEVILLE AROUND SUNSET. RUC AND ETA DEVELOP QPF FROM I-72 SOUTH THIS AFTERNOON AND HAVE LIKELY CHANCE OF SHOWERS AND THUNDERSTORMS HERE. CHANCE OF SHOWERS NORTH OF I-72 WHERE ATMOSPHERE NOT AS UNSTABLE AND PERHAPS A THUNDERSTORMS AS SECONDARY FRONT SLIDING SOUTH TOWARD I-74 FROM I-80. MOST UNSTABLE AIR OVER FAR SE IL NEAR LAWRENCEVILLE WITH HIGHS UPPER 80S TO NEAR 90 AND DEWPOINTS IN THE MID TO UPPER 70S AND THIS AIR MASS SHIFTING GRADUALLY SE. THIS WILL BE BEST CHANCE OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EARLY EVENING AND SPC HAS SHIFTED SLIGHT RISK OF SEVERE THUNDERSTORMS JUST SOUTHEAST OF LAWRENCEVILLE FOR TODAY. NOT AS HOT TODAY WITH MORE CLOUD COVER AND FRONTS MOVING THRU WITH WINDS BECOMING NORTH AND HAVE HIGHS RANGING FROM THE LOWER 80S FROM I-74 NORTH TO THE UPPER 80S TO NEAR 90 SE IL. && .PREV DISCUSSION...SEVERAL MCS/S HAVE DEVELOPED DURING THE OVERNIGHT HOURS OVER THE MIDWEST...EXTENDING FROM THE CHICAGO AREA SOUTHWESTWARD INTO NORTHERN MISSOURI. THIS WILL BE THE MAIN FORECAST PROBLEM IN THE SHORT TERM. BEYOND TODAY...DRY AND COOLER WEATHER WILL BE THE RULE. SHORT TERM...TODAY THROUGH FRIDAY... 00Z ETA CONTINUES HAVE THE BEST HANDLE ON THE WEATHER IN THE SHORT TERM. AS OF 08Z...SURFACE LOW WAS OVER NORTHEASTERN MISSOURI AND WILL TRACK TO THE EAST ACROSS CWA...ALONG THE I-72 COORIDOR. MAIN CONCERN FOR THE MORNING HOURS WILL BE THE HEAVY RAINFALL... ESPECIALLY NORTH OF I-72...BUT WITH HIGH FLASH FLOOD VALUES WILL ONLY KEEP MENTION OF HEAVY RAINFALL POSSIBLE IN THE ZONES. AS FOR ANY SEVERE WEATHER...SOME CONCERN FOR OUR EASTERN AND SOUTHEASTERN COUNTIES AS THEY HAVE NOT HAD ANY RAIN YET AND LI/S NEAR MINUS 4 AND CAPES NEAR 2000 J/KG. HOWEVER...THE RAIN SHOULD REACH THOSE AREAS BETWEEN 12Z AND 13Z...EFFECTIVELY KILLING ANY SEVERE POTENTIAL. THERE IS STILL A SLIGHT CHANCE THESE AREAS COULD RECOVER ENOUGH FOR THE POSSIBILITY OF SEVERE WEATHER. AS FOR TEMPERATURES...WILL HAVE A WIDE RANGE OF HIGHS...FROM NEAR 80 IN THE NORTHWEST TO NEAR 90 IN THE SOUTHEAST. LOW QUICKLY EXITS THE REGION BY THIS EVENING...WITH SOME LINGERING RAIN EAST OF I-57 THROUGH MIDNIGHT BEFORE COMING TO AN END. FOR THURSDAY AND FRIDAY...WILL SEE RIDGE OF HIGH PRESSURE SINK SOUTH OVER THE REGION...BRINGING IN DRY AND COOLER WEATHER. LONG TERM...FRIDAY NIGHT THROUGH TUESDAY... PLEASANT WEATHER TO CONTINUE INTO THE WEEKEND. HOWEVER...BY SATURDAY...RIDGE MOVES OFF TO THE EAST ALLOWING SOUTHERLY WINDS TO RETURN TO THE REGION AND WE BEGIN A SLOW WARMUP. NEXT CHANCE FOR RAIN WILL BE MONDAY AND TUESDAY...SO NO MAJOR CHANGES MADE TO THE EXTENDED AT THIS TIME. && .ILX WATCHES/WARNINGS/ADVISORIES... IL...NONE. && $$ HUETTL/BYRD il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 326 PM EDT WED AUG 4 2004 .DISCUSSION... THE MAIN CONCERN WITH THIS FORECAST PACKAGE IS THE OVERNIGHT LOWS TONIGHT. WATER VAPOR IMAGERY AND RUC/ETA SHOWING A CLOSED LOW OVER NEW FOUNDLAND...A RIDGE STRETCHING FROM NEW MEXICO NORTHWARD TO SASKATCHEWAN...AND A LOW OFF THE COAST OF BRITISH COLUMBIA. A WEAK SHORTWAVE IS OVER WESTERN ONTARIO AND SOUTHERN MANITOBA ROTATING THROUGH THE BASE OF THE EAST COAST LOW. THIS WAS GENERATING SOME CUMULUS OVER WESTERN ONTARIO AND THE ARROWHEAD OF MINNESOTA. SURFACE ANALYSIS DEPICTS A LOW OVER THE OHIO RIVER VALLEY WITH A COLD FRONT DRAPED SOUTHWEST INTO OKLAHOMA. THIS COLD FRONT CONTINUES TO BE PUSHED ALONG BY A BROAD RIDGE CENTERED OVER NORTHERN LAKE WINNIPEG. THE RIDGE IS DRAWING DRY AIR INTO THE UPPER GREAT LAKES. THE SHORTWAVE OVER WESTERN ONTARIO WILL SHIFT ACROSS THE U.P. THIS EVENING FOLLOWED BY ANOTHER WEAK SHORTWAVE. THE SURFACE RIDGE WILL CONTINUE TO PUSH INTO THE UPPER GREAT LAKES AND WILL BE CENTERED OVER WESTERN ONTARIO BY THURSDAY MORNING. THE FORECAST SOUNDING DATA INDICATES THAT THE AIR MASS WILL BE DRY WITH MEAN SURFACE-500MB RH LESS THAN 40 PERCENT. SURFACE TRAJECTORY FORECAST DRAWING THE AIR MASS FROM WESTERN ONTARIO THIS MORNING INTO THE FORECAST AREA THURSDAY MORNING. COLD AIR ADVECTION IS SHOWING A 5C DROP IN TEMPERATURES OVER THE AREA AT 850MB TONIGHT. THUS THE OVERNIGHT LOWS SHOULD BE COOLER THAN YESTERDAY. GUIDANCE AND TRAJECTORY FORECAST SUPPORTS OVERNIGHT LOW TEMPERATURES IN THE MID 40S. THE UPPER LEVEL RIDGE WILL SLOWLY SLIDE ACROSS THE MINNESOTA THROUGH SATURDAY NIGHT. THE SURFACE RIDGE WILL BE OVER THE UPPER GREAT LAKES ON FRIDAY...BLANKETING MUCH OF THE UPPER GREAT LAKES AND THE OHIO RIVER VALLEY ON SATURDAY AND SATURDAY NIGHT. MEANWHILE A SURFACE LOW WILL DEVELOP OVER SASKATCHEWAN ON FRIDAY. FRONTOGENESIS WILL PRODUCE A COLD FRONT OVER THE NORTHERN PLAINS ON SATURDAY STRETCHING FROM THIS LOW AS IT MOVES INTO MANITOBA. THE LOW WILL MOVE INTO NORTHEAST MANITOBA SATURDAY NIGHT DRAGGING THE COLD FRONT INTO WESTERN MINNESOTA AND THE CENTRAL PLAINS. THE AIR MASS IS EXPECTED TO REMAIN FAIR AND DRY THROUGH THIS PERIOD. A MID LEVEL LOW WILL DEVELOP OVER SOUTHERN SASKATCHEWAN SATURDAY NIGHT AND MOVE TO SOUTHWEST MANITOBA ON SUNDAY...ALL THE WHILE SENDING WEAK SHORTWAVE THROUGH THE RIDGE OVER MINNESOTA...AND SLOWLY BREAKING IT DOWN. THE SURFACE LOW WILL MOVE VERY LITTLE ON SUNDAY...WHILE THE COLD FRONT SHIFTS INTO EASTERN MINNESOTA. ISENTROPIC LIFT AHEAD OF THE SURFACE FRONT COULD TRIGGER SHOWERS AND THUNDERSTORMS AS A WEAK SHORTWAVE SHOOTS THROUGH THE RIDGE AND OVER THE AREA. THE EXTENDED MODELS DIVERGE AT THIS POINT. GLOBAL IS WEAKEST AND MOST PROGRESSIVE WITH THE NEXT SYSTEM MOVING THROUGH THE AREA. ECMWF IS THE SLOWEST WHILE GFS IS A COMPROMISE. GFS TREND ALSO IS FASTER. GLOBAL ENSEMBLE SIMILAR TO GFS SO WILL FOLLOW THE GFS COMPROMISE AS WELL. THE MID LEVEL CLOSED LOW WILL MOVE INTO MINNESOTA SUNDAY NIGHT. Q-VECTOR CONVERGENCE ACCOMPANYING THIS SYSTEM WILL OVERSPREAD THE FORECAST AREA. THE SURFACE LOW WILL MOVE INTO WESTERN U.P. ESCORTING THE COLD FRONT INTO THE FORECAST AREA AND THE MIDDLE MISSISSIPPI RIVER VALLEY. INSTABILITY AND MOISTURE ACCOMPANYING THE FRONTAL SYSTEM AND THE MID LEVEL LOW WILL INTENSIFY OF THE FORECAST AREA GENERATING MORE SHOWERS AND THUNDERSTORMS. THE CLOSED LOW WILL MOVE TO NORTHERN WISCONSIN WHILE THE SURFACE LOW WILL MOVE OVER THE CENTRAL U.P. THE LOW WILL REMAIN OVER THE U.P. THROUGH TUESDAY. THE SURFACE RIDGE WILL PUSH INTO THE AREA TUESDAY NIGHT AND WEDNESDAY. GFS IS KEEP PRECIPITATION OVER THE AREA...HOWEVER...THE RIDGE SHOULD BE DRAWING DRIER AIR INTO THE AREA AND FAIR WEATHER WILL RETURN. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DLG mi AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 845 AM EDT WED AUG 4 2004 .UPDATE... SATELLITE AND RADAR TRENDS CERTAINLY SUGGEST THE HEAVY RAINFALL WILL BE MUCH FURTHER SOUTH. 06Z AND 09Z RUNS OF GFS...ETA...AND RUC STILL HAVE A POOR HANDLE ON CURRENT CONVECTIVE SYSTEMS. NEXT BATCH OF RAIN TO MOVE THROUGH SOUTHEAST MICHIGAN ONLY HAD ABOUT ONE TENTH TO HALF INCH OF RAIN OVER NRN IL AND NORTHWEST IN. GIVEN THAT THE FIRST BATCH OF THUNDERSTORMS HAD BETWEEN A HALF INCH TO ONE INCH OF RAIN...AND THE FACT ONLY SOME MINOR URBAN FLOODING HAS OCCURRED...WILL DROP THE FLOOD WATCH. ANY ADDITIONAL STRONG CONVECTION WILL FIRE WELL SOUTH OF THE STATE...ALONG THE OUTFLOW BOUNDARY FROM LAST NIGHTS CONVECTION. THEREFORE...WILL ALSO TEMPER THE THUNDERSTORM WORDING IN THE UPDATE. RBP && .PREV DISCUSSION... 00Z RAOBS/WATER VAPOR LOOP SHOW UPPER LOW OVER QUEBEC WITH A TROUGH DROPPING INTO THE NORTHERN GREAT LAKES. ANOTHER SHORTWAVE OVER THE DAKOTAS...WITH A CONVECTIVELY INDUCED VORT NEAR THE MID MISSISSIPPI VALLEY. SURFACE ANALYSIS SHOWS LOW OVER KANSAS WITH A FRONT EXTENDING NORTHEAST THROUGH ILLINOIS TO FAR SOUTHERN LOWER MICHIGAN. REGIONAL RADARS SHOW A MULTITUDE OF CONVECTION UPSTREAM...FORMERLY SEPARATED INTO TWO DISTINCT MCS/S BUT NOT MORE WIDESPREAD. MAIN FORECAST FOCUS CONTINUES TO REVOLVE AROUND TODAY...WITH PRECIP AND HEAVY RAIN POTENTIAL THE MAIN CONCERN. ETA/GFS BOTH STILL HAVE FEEDBACK ISSUES...BUT NOT NECESSARILY AS BAD AS EARLIER RUNS. ETA REMAINS MORE CONSISTENT COMPARED TO EARLIER RUNS REGARDING THE TRACK OF THE SURFACE LOW /WHICH IS NOT GOOD/. HOWEVER THE GFS AND CANADIAN BOTH HAVE TRENDED FARTHER SOUTH WITH THE WAVE. ETA DID NOT CAPTURE THE FIRST MCS THAT SWEPT ACROSS NORTHERN ILLINOIS OVERNIGHT. THIS SYSTEM ATE UP SOME OF THE LINGERING INSTABILITY...AS WELL AS ENHANCED/PUSHED THE BAROCLINIC ZONE FARTHER SOUTH WITH ITS OUTFLOW. UPSTREAM COMPLEX OVER IOWA HAD BEEN TRACKING ALMOST DUE SOUTH INTO MISSOURI...BUT HAS BEGUN TO TURN TO THE SOUTHEAST INTO THE UNSTABLE AIR ACROSS SOUTHERN ILLINOIS. THIS WOULD BRING THE MORE STRATIFORM PRECIP NORTH OF THE COMPLEX THROUGH SOUTHERN LOWER...BUT WITH THE MAIN BAROCLINIC ZONE AND HIGHEST QPF SOUTH OF THE STATE. THIS IS CONTRARY TO THE ETA FORECAST...WHICH BRINGS MAIN BULLSEYE OF LIFT FROM THIS SYSTEM INTO SOUTHERN LAKE MICHIGAN AND EVENTUALLY ACROSS SOUTHEAST MICHIGAN. GIVEN RECENT TRENDS AND OVERALL SETUP...WOULD EXPECT THE HIGHEST QPF TO FALL FARTHER SOUTH ACROSS INDIANA AND OHIO. THIS IS ALSO IN LINE WITH LATEST NCEP QPF AND EXCESSIVE RAINFALL GRAPHICS. FOR TODAY...EXPECT A COUPLE ROUNDS OF WIDESPREAD PRECIP...HOWEVER FIRST ONE WILL BE WINDING DOWN AROUND FORECAST ISSUANCE. LONG-LIVED SQUALL LINE IS ONLY NOW BEGINNING TO WEAKEN ACROSS CENTRAL LOWER/EASTERN INDIANA AS IT MOVES INTO A MORE STABLE AIRMASS. LARGE AREA OF STRATIFORM PRECIP EXTENDS ACROSS MUCH OF LOWER MICHIGAN... HOWEVER DRY AIR HAS BEEN A LIMITING FACTOR FARTHER NORTH. TIGHT 850MB THETA-E GRADIENT DEPICTED ACROSS THE CENTRAL CWA...ALONG WHICH A FEW THUNDERSTORMS HAVE DEVELOPED OUT AHEAD OF THE MAIN BATCH. FARTHER NORTH THERE IS NO INSTABILITY TO SPEAK OF AND DRY AIR FEEDING AROUND SURFACE RIDGE OVER THE NORTHERN GREAT LAKES. EXPECT A SHARP CUTOFF IN QPF...AND WILL ONLY KEEP CHANCE RW ACROSS THE FAR NORTHERN CWA. FARTHER SOUTH THOUGH CATEGORICAL SHOULD BE BETTER. CURRENT WIDESPREAD PRECIP WILL BE OUT JUST AROUND THE TECHNICAL START OF THE FIRST PERIOD. HOWEVER NEXT AREA OF RAIN IS CURRENTLY ACROSS NORTHERN ILLINOIS. REGIONAL RADARS SHOW THESE TWO AREAS ARE BEGINNING TO FILL IN...WHICH WOULD SUPPORT NOT TRYING TO TIME A BREAK BETWEEN THE TWO. WILL WORD THE GRIDS OCCASIONAL RAIN WITH SCATTERED THUNDERSTORMS. IN ADDITION TO COVERAGE OF PRECIP...INTENSITY IS ALSO A CONCERN. A JUICY AIRMASS WITH PRECIPITABLE WATERS OBSERVED AROUND 1.75" AT 00Z...HOWEVER VALUES POOLED AROUND 2" OR MORE ARE NOT UNREASONABLE. BASED ON UPSTREAM METAR REPORTS ACROSS WISCONSIN/ILLINOIS AND RECENT WEAKENING TREND OBSERVED...WOULD EXPECT ABOUT 0.50-1.00" OF PRECIP WITH THIS FIRST COMPLEX...MAINLY ALONG AND SOUTH OF I-69. THAT MUCH RAIN SHOULD NOT CREATE TOO MUCH OF A PROBLEM...HOWEVER QUESTION REMAINS AS TO WHAT WILL FALL DURING THE REST OF THE DAY. AS MENTIONED ABOVE...EXPECT HIGHEST QPF TO FALL FARTHER SOUTH TOWARD THE OHIO VALLEY. HOWEVER BASED ON ADJUSTED MODEL GUIDANCE AND UPSTREAM OBSERVATIONS...WOULD EXPECT TO SEE ROUGHLY ANOTHER INCH OF QPF ACROSS THE SOUTHERN CWA. THIS PRESENTS MORE OF A PROBLEM...WITH UP TO 2 INCHES TOTAL ACROSS THE SOUTHERN CWA. THIS IS THE SAME AREA WHICH SAW UP TO AN INCH OF RAIN LAST NIGHT WITH THE CONVECTIVE THAT DEVELOPED OVER THE CWA. EARLIER SPOTTER REPORTS INDICATED THE HIGHEST VALUES FELL GENERALLY SOUTHEAST OF THE OFFICE /E.G. TROY BLOOMFIELD DEARBORN WYANDOTTE/. THIS RAIN CAUSED A SOME RISES ON AREA RIVERS...AND IS ALSO WHY FLASH FLOOD GUIDANCE IS LOWEST ACROSS THE SOUTHEAST. WITH THIS IN MIND...WILL ISSUE A FLOOD WATCH FOR TODAY FOR THE SOUTHERN CWA BASICALLY ALONG AND SOUTH OF M-59 /LIVINGSTON TO MACOMB/. NOT TOO SURE ABOUT THE NORTHERN TIER OF COUNTIES... ESPECIALLY SINCE MACOMB MAY RECEIVE THE LOWEST PRECIP IN THE WATCH AREA. /FARTHER EAST THE THE CWA THE DRY/STABLE AIR WILL DOMINATE LONGER...SO THEY WILL NOT SEE AS MUCH FROM THE CURRENT EARLY MORNING SYSTEM THAT CONTINUES TO WEAKEN AS IT MOVES EAST./ HOWEVER THEY ALSO HAVE ONE OF THE LOWEST FFG VALUES GIVEN EARLIER RAIN...SO IT WOULD BE PRUDENT TO INCLUDE THEM IN THE WATCH. OTHERWISE DID NOT MAKE MANY CHANGES TO THE REMAINDER OF THE FORECAST. COULD SEE SOME LINGERING PRECIP ACROSS THE SOUTHEAST CWA THIS EVENING...UNTIL THE SYSTEM FINALLY CLEARS EAST. HOWEVER GIVEN EXPECTED FARTHER SOUTH TRACK...WILL KEEP POPS BELOW MOS GUIDANCE. UPPER TROUGH OVER THE NORTHERN LAKES DIGS ACROSS THE REGION TONIGHT...CARVING OUT A LONGWAVE TROUGH OVER THE EASTERN CONUS. CANADIAN SURFACE HIGH BUILDS DOWN ACROSS THE WESTERN GREAT LAKES...LEAVING SOUTHEAST MICHIGAN IN A SOMEWHAT BRISK NORTHERLY FLOW. ETA/GFS BOTH DROP 850MB TEMPS TO 5-6C IN THERMAL TROUGH THAT CROSSES THE REGION THURSDAY NIGHT. && .DTX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ BRAVENDER EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPRINGFIELD MO 247 PM CDT WED AUG 4 2004 ...MESOSCALE CONVECTIVE DISCUSSION... THE ENVIRONMENT OVER THE SOUTHERN HALF OF MISSOURI HAS BEEN GRADUALLY DESTABILIZING TODAY...WITH EARLY AFTERNOON TEMPS IN THE UPPER 80S AND DEW POINTS IN THE LOW 70S. A SPECIAL RAOB RELEASED SHORTLY BEFORE 200 PM INDICATED THAT THE MIXED LAYER CONVECTIVE INHIBITION HAD WEAKENED TO AROUND 40 J/KG. RUC SOUNDING PROGS SHOW THE CAP BREAKING BY 330-430 PM. CUMULUS HAVE BEEN DEVELOPING OVER THE LAST 30 MINUTES WHICH ALSO INDICATES A WEAKENING CAP. SATELLITE TRENDS DEPICT A THIN LINE...INDICATIVE OF A PRE-FRONTAL TROUGH. A LINE OF THUNDERSTORMS WILL LIKELY FIRE ALONG THIS FEATURE OVER CENTRAL MISSOURI...EVENTUALLY BUILDING DOWN INTO SOUTHWEST MISSOURI AS THE LATE AFTERNOON PROGRESSES. MIXED LAYER CAPES OF 2000 - 2500 J/KG SHOULD BE SUFFICIENT FOR A FEW MICRO-BURSTS WITH THE STRONGER STORMS. CRAMER .DISCUSSION... SHORT TERM (TONIGHT - FRIDAY)... CHALLENGES IN THE SHORT TERM REVOLVE AROUND THIS AFTERNOON AND TONIGHT'S ACTIVE WEATHER. THE COLD FRONT STALLED OUT TEMPORARILY OVER EASTERN KANSAS THIS MORNING...AND WILL MOVE THROUGH THE CWA A LITTLE SLOWER THAN EXPECTED. CLEARING SKIES ALONG WITH COPIOUS AMOUNTS OF MOISTURE ACROSS THE REGION MAY PROVIDE ENOUGH INSTABILITY FOR STRONG TO SEVERE STORMS LATER THIS AFTERNOON AND THIS EVENING...AS THE COLD FRONT PUSHES THROUGH SOUTHERN MISSOURI. I MAY HAVE TO HOLD ON TO PRECIPITATION CHANCES OVER MY SOUTHEAST COUNTIES INTO TONIGHT'S PERIOD DUE TO THE FRONT CLEARING THE AREA WITHIN THE SECOND PERIOD. THE REST OF THE SHORT TERM LOOKS DRY AND COOL AS THE NORTHERN AIRMASS SPREADS ACROSS THE CWA TONIGHT. THE SUMMER TIME RIDGE WILL CONTINUE TO RETREAT BACK INTO THE INTERMOUNTAIN WEST. THIS WILL ALLOW THE COLD FRONT TO SCOUR OUT THE ENTIRE DEEP SOUTH AND PENETRATE INTO THE GULF OF MEXICO. TEMPERATURES OVER THE NEXT COUPLE OF DAYS WILL REMAIN WELL BELOW NORMAL...WITH AFTERNOON HIGHS THURSDAY AND FRIDAY IN THE LOW TO MID 80S. OVERNIGHT LOWS IN THE 50S AND 60S TONIGHT AND THURSDAY NIGHT. LONG TERM (SATURDAY - TUESDAY)... THE ECMWF AND GFS HAVE BOTH BEEN CONSISTENT WITH A PATTERN CHANGE WITHIN THE LONG TERM PERIODS. RIDGE CONTINUES ITS WESTWARD EXPANSION ALLOWING A LONG WAVE TROUGH TO ANCHOR INTO THE EASTERN HALF OF THE CONUS. THE EASTERN PLAINS AND MISSOURI VALLEY REGION REMAINS UNDER THE INFLUENCE OF STRONG NORTHWEST FLOW WITH SEVERAL SIGNALS OF SHORTWAVES AFFECTING THE AREA. ONE SIGNIFICANT WAVE THAT THE LONG TERM MODELS POINT OUT PUSHES THROUGH BY MONDAY. ONGOING FORECAST HANDLES THIS WELL WITH 30 POPS ACROSS THE BOARD. OTHERWISE...WITH THE LACK OF MOISTURE...NO SIGNIFICANT PRECIPITATION CHANCES ARE FORESEEABLE AT THIS POINT. TEMPERATURES SHOULD REMAIN BELOW NORMAL THROUGH DAY 7. && .AVIATION... SEVERAL AVIATION CONCERNS LIE WITHIN THE NEXT 24 HOURS FOR SOUTHERN AND CENTRAL MISSOURI. STRONG TO SEVERE THUNDERSTORMS WILL BE POSSIBLE THIS AFTERNOON INTO TONIGHT AS A COLD FRONT WEDGES IN. AS THE FRONT PUSHES SOUTH OF THE REGION LATE TONIGHT...CEILINGS WILL FALL TO AROUND 1000 FEET WITH THE DECK OF STRATUS THATS EXPECTED. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. $$ CRAMER mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 255 PM CDT WED AUG 4 2004 .SHORT TERM... 12Z ETA/GFS INITIALIZED WELL...AND ARE IN GOOD AGREEMENT THROUGH FRIDAY MORNING. WITH DIFFERENCES BEYOND FRIDAY MORNING...WILL SIDE WITH 12Z ETA FOR DETAILS AS GFS SEEMS TOO STRONG WITH 500MB LOW APPROACHING REGION OVER THE WEEKEND. BOTH MODELS DO HAVE SIMILAR TIMING WITH SURFACE AND UPPER LEVEL FEATURES THROUGH PERIOD...WITH QPF AND AMPLITUDE DIFFERENCES NOTED. FORECAST CHALLENGES WILL BE TEMPERATURES AND CONVECTIVE CHANCES OVER THE WEEKEND. TONIGHT...HIGH PRESSURE WILL CONTINUE TO BUILD FROM NORTH OF THE BORDER. CURRENT RADAR IMAGERY SHOWS BAND OF SHOWERS ASSOCIATED WITH 700MB FRONTOGENESIS ACROSS CENTRAL NORTH DAKOTA. RUC40 INDICATES 700MB FRONTOGENESIS NEAR WESTERN PORTION OF FORECAST AREA BY EVENING. HOWEVER...DRY AIR FILTERING IN WITH HIGH PRESSURE...THUS EXPECT SHOWERS TO DISSIPATE AS THEY APPROACH...WILL NOT MENTION. CENTER OF HIGH WILL BE LOCATED JUST EAST OF FORECAST AREA BY MORNING WITH WEAK RETURN FLOW SETTING UP. AFTERNOON CUMULUS WILL DISSIPATE AFTER SUNSET...SETTING UP MOSTLY CLEAR SKIES. EXPECT DRIEST AIR...LIGHTEST WINDS...AND THUS COOLEST LOW TEMPERATURES (MID 40S) ACROSS EASTERN FORECAST AREA. REMAINDER OF AREA SHOULD SEE DEW POINTS...AND LOW TEMPS NEAR 50. THURSDAY THRU FRIDAY...SURFACE HIGH DROPS SOUTHEAST WITH UPPER RIDGE BUILDING OVER REGION. 850MB TEMPERATURES WARM A FEW DEGREES EACH DAY...SO EXPECT HIGHS AND LOWS TO BE SLIGHTLY HIGHER THAN EACH PREVIOUS DAY. MOSTLY SUNNY SKIES ALSO EXPECTED WITH DRY AIR (HIGH CONVECTIVE TEMPS) IN PLACE. STRONGER SHORTWAVES RIDING OVER THE TOP OF THE RIDGE LOOK TO REMAIN WEST AND SOUTH OF FORECAST AREA. WEAK SHORTWAVES THAT DO ENTER FORECAST AREA SHOULD HAVE LITTLE INFLUENCE AS MOIST AIR REMAINS WEST UNTIL SATURDAY. SATURDAY...SURFACE TROUGH TO BE LOCATED OVER EASTERN NORTH DAKOTA BY AFTERNOON. REMOVED THUNDER CHANCES FRIDAY NIGHT/SATURDAY MORNING WITH SLOWER SOLUTIONS. KEPT THUNDER CHANCES SATURDAY AFTERNOON. .LONG TERM...SUN THROUGH WED...MODELS REMAIN INCONSISTENT...WITH UKMET NOT CUTTING OFF 500MB LOW AND GFS DEVELOPING A STRONG 500MB CUTOFF LOW OVER THE N PLAINS. ECMWF IS THE COMPROMISE SOLUTION...SO LEANED TOWARDS IT FOR FORECAST. LOW PRESSURE MOVES THROUGH AREA AS UPPER LEVEL RIDGE PASSES ON SAT NIGHT AND SUN...SO KEPT CHANCE FOR THUNDER ON SAT NIGHT AND THEN SUN DRY. UPPER LEVEL LOW THAN MOVES TOWARDS REGION...BRINGING THE NEXT CHANCE FOR PRECIPITATION TO THE AREA ON SUN NIGHT...MON AND MON NIGHT. UPPER LEVEL LOW THEN SHIFTS E OF THE AREA...WITH NW FLOW PREDOMINATING FOR TUE AND WED. AS FAR AS TEMPS...NEEDED TO CUT TEMPERATURES FOR SOME DAYS...ENDING UP WITH BELOW NORMAL TEMPERATURES FOR ALL OF THE EXTENDED FORECAST. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ TG/NG nd AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE CLEVELAND OHIO 215 PM EDT WED AUG 4 2004 AVIATION(18Z-18Z)... WK LOW PRES OVR CNTRL OH INTO SRN IN WL MOV SE AND EVENTUALLY DRAG RMNG LOW CLDS AND RA SE WITH THE LOW. HIGH PRES BLDG INTO MN WL PUSH MUCH DRIER AIR SE TWD AREA. LEADING EDGE OF DRY AIR WL BE SHOWN TO PUSH SSE ACRS TAF SITES ABT 00Z TO 02Z AND ABT 05Z TO 07Z FURTHER INLAND SITES. AMS MOIST FM SFC UP TO MID LVLS SO EXACT HGT OF CLD BASES LARGELY A GUESS. RISK FOR THUNDER HAS SHIFTED SE OF TAF SITES. && .SHORT TERM(THIS AFTERNOON)... WITH RAIN LOWERED HIGHS AND IN AREAS WITH FROPA INCREASED WINDS AND LOWERED HIGHS. REMOVED MENTION OF THUNDER AS PER 88D AND LTNG DETECTION. && .PREV SHORT TERM (TODAY THROUGH THURSDAY)... WL MAKE THIS QUICK AS I WANT TO HAVE MOST PRODUCTS OUT SO I CAN WATCH THE RADAR. FIRST COMPLEX OF STORMS DRIVING EAST AT 45 KTS. WL HAVE TO WATCH FOR WIND DAMAGE EVEN THOUGH SYSTEM WEAKENING. LOW LEVEL INSTABILITY NOT IMPRESSIVE BUT SOME DECENT ELEVATED CAPE. LOW LEVEL JET PRIMARILY TO OUR WEST OVER MIDWEST. MODELS FAILING TO GRASP STRENGTH OF FIRST COMPLEX AND SECOND SYSTEM IN IOWA ALREADY FARTHER SOUTH THAN PROGGED. SURFACE FRONT APPEARS TO BE JUST S OF LAKE ERIE. ALL MODELS STILL HAVING FEEDBACK ISSUES. OF EVERYTHING I LOOKED AT THE RUC10 SEEMS MOST REASONABLE WITH WEAKENING MORNING SYTEM AND THEN REDEVELOPMENT ALONG FRONTAL BOUNDARY THIS AFTERNOON SHIFTING EWRD TNGT. WL FOLLOW THIS SCENARIO IN WRITING FCST. PCP WATER HIGH ON BUFKIT IN BOTH ETA AND GFS BUT BOTH SEEM CONTAMINATED BY FEEDBACK. 3 HR FLOOD GUIDANCE FAIRLY HIGH (AROUND 3 INCHES) EXCEPT FOR NW PA WHERE IT IS CLOSER TO 2 INCHES. SURROUNDING OFFICES WANT FLOOD WATCH AND WITH RECENT RELATIVELY DRY WEATHER AND UNCERTAINTY ABOUT WHERE EXACTLY THE HEAVIEST RAIN WILL SET UP AM LEANING TOWARD ONLY ISSUING FOR PA COUNTIES FOR NOW WHERE FLOOD GUIDANCE LOWEST ALTHOUGH WILL MENTION HEAVY RAIN MOST ZONES. NGM AND GFS TEMP GUIDACE SEEMS REASONABLE WITH UPPER 70S/AROUND 80 TODAY AND UPPER 60S/LOWER 70S THURSDAY. && .LONG TERM(FRI-TUE)... WL NOT MAKE MANY CHANGES TO EXTENDED AT THIS TIME. FIRST GLANCE OF CURRENT GRIDS LOOK OK. WL LEAVE PREVIOUS DISCUSSION FROM YESTERDAY SINCE IT STILL APPLIES. PREVIOUS LONG TERM DISCUSSION FROM TUESDAY AFTERNOON... MDLS IN GEN AGREEMENT WITH COOL NLY FLOW FOR FRI AND WITH H8 AND LK TEMP DIF IN EXCESS OF 13C AND SOME MSTR AS PER LAST FEW MDL RUNS WILL MENTION CHC SHWRS ERN FORECAST AREA. COOL TEMPS OVR THE WEEKEND LOOK REASONABLE BASED ON H8 TEMPS AND ENSEMBLE. H8 MAY NOT GET AS COOL AS FCST HOWEVER 7C LOOKS GOOD. THREAT OF WATERSPOUTS IS PSBL...NO MENTION ATTM. SOME TIMG CONFLICTS FOR THE FRONTAL SYS FOR MONDAY AND TUE...WL KEEP MONDAY DRY AS FRONT STILL TOO THE WEST. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...FLOOD WATCH NW PA LATE AFTERNOON AND TONIGHT. && $$ SHORT TERM...KIELTYKA PREV SHORT TERM...KOSARIK LONG TERM...KOSARIK/KIELTYKA AVIATION...MWA oh AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE CLEVELAND OHIO 1101 AM EDT WED AUG 4 2004 .SHORT TERM(THIS AFTERNOON)... PLENTY OF CLOUDS ACROSS REGION THIS MORNING ALONG WITH RAINFALL CONTINUING TO MOVE EASTWARD. LATEST RADAR IMAGE SHOWING HEAVIEST RAINFALL AND THUNDERSTORM ACTIVITY ACROSS SOUTHERN PORTIONS OF THE CWA THIS AM. FRONTAL BOUNDRY ATTM LOCATED ACROSS NORTHERN OHIO. FOR THIS AFTERNOON LOWERED TEMPS A CAT DUE CLOUDS AND PRECIP AND REMOVED MORNING WORDING IN EASTERN ZONES AND DOWNPLAYED THUNDER ACROSS NORTHERN AREAS. .PREV SHORT TERM (TODAY THROUGH THURSDAY)... WL MAKE THIS QUICK AS I WANT TO HAVE MOST PRODUCTS OUT SO I CAN WATCH THE RADAR. FIRST COMPLEX OF STORMS DRIVING EAST AT 45 KTS. WL HAVE TO WATCH FOR WIND DAMAGE EVEN THOUGH SYSTEM WEAKENING. LOW LEVEL INSTABILITY NOT IMPRESSIVE BUT SOME DECENT ELEVATED CAPE. LOW LEVEL JET PRIMARILY TO OUR WEST OVER MIDWEST. MODELS FAILING TO GRASP STRENGTH OF FIRST COMPLEX AND SECOND SYSTEM IN IOWA ALREADY FARTHER SOUTH THAN PROGGED. SURFACE FRONT APPEARS TO BE JUST S OF LAKE ERIE. ALL MODELS STILL HAVING FEEDBACK ISSUES. OF EVERYTHING I LOOKED AT THE RUC10 SEEMS MOST REASONABLE WITH WEAKENING MORNING SYTEM AND THEN REDEVELOPMENT ALONG FRONTAL BOUNDARY THIS AFTERNOON SHIFTING EWRD TNGT. WL FOLLOW THIS SCENARIO IN WRITING FCST. PCP WATER HIGH ON BUFKIT IN BOTH ETA AND GFS BUT BOTH SEEM CONTAMINATED BY FEEDBACK. 3 HR FLOOD GUIDANCE FAIRLY HIGH (AROUND 3 INCHES) EXCEPT FOR NW PA WHERE IT IS CLOSER TO 2 INCHES. SURROUNDING OFFICES WANT FLOOD WATCH AND WITH RECENT RELATIVELY DRY WEATHER AND UNCERTAINTY ABOUT WHERE EXACTLY THE HEAVIEST RAIN WILL SET UP AM LEANING TOWARD ONLY ISSUING FOR PA COUNTIES FOR NOW WHERE FLOOD GUIDANCE LOWEST ALTHOUGH WILL MENTION HEAVY RAIN MOST ZONES. NGM AND GFS TEMP GUIDACE SEEMS REASONABLE WITH UPPER 70S/AROUND 80 TODAY AND UPPER 60S/LOWER 70S THURSDAY. && .LONG TERM(FRI-TUE)... WL NOT MAKE MANY CHANGES TO EXTENDED AT THIS TIME. FIRST GLANCE OF CURRENT GRIDS LOOK OK. WL LEAVE PREVIOUS DISCUSSION FROM YESTERDAY SINCE IT STILL APPLIES. PREVIOUS LONG TERM DISCUSSION FROM TUESDAY AFTERNOON... MDLS IN GEN AGREEMENT WITH COOL NLY FLOW FOR FRI AND WITH H8 AND LK TEMP DIF IN EXCESS OF 13C AND SOME MSTR AS PER LAST FEW MDL RUNS WILL MENTION CHC SHWRS ERN FORECAST AREA. COOL TEMPS OVR THE WEEKEND LOOK REASONABLE BASED ON H8 TEMPS AND ENSEMBLE. H8 MAY NOT GET AS COOL AS FCST HOWEVER 7C LOOKS GOOD. THREAT OF WATERSPOUTS IS PSBL...NO MENTION ATTM. SOME TIMG CONFLICTS FOR THE FRONTAL SYS FOR MONDAY AND TUE...WL KEEP MONDAY DRY AS FRONT STILL TOO THE WEST. && AVIATION(06Z-06Z)... CLUSTER OF SEVERE THUNDERSTORMS NC IN MOVING ALONG WARM FRONT STRETCHED ACROSS NORTHERN OHIO. ARE STARTING TO WEAKEN AS THEY OUT RUN LL JET...SHOULD REACH TOL AROUND 8Z AND IF THEY HOLD TOGETHER CLE AROUND 10Z. EXPECT A LITTLE MORE OF A SOUTHEASTERLY TRACK AFTER IT HITS OHIO BORDER. SECOND CLUSTER IN IA MAY NOT HOLD TOGETHER. BUT AS LOW NEAR KC MOVES ACROSS CENTRAL OHIO TONIGHT...EXPECT SECOND ROUND OF THUNDERSTORMS TO DEVELOP AHEAD OF IT LATER THIS AFTERNOON AND EVENING. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...FLOOD WATCH NW PA LATE AFTERNOON AND TONIGHT. && $$ SHORT TERM...ABE PREV SHORT TERM...KOSARIK LONG TERM...KOSARIK/KIELTYKA AVIATION...DJB oh AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PITTSBURGH PA 935 PM EDT WED AUG 4 2004 .SHORT TERM (REST OF TONIGHT)... WILL LOWER POPS IN NRN TIER OF FA AND KEEP LIKELY FURTHER SOUTH AS FRONT SLOWLY SAGS SEWRD. WILL KEEP IN MENTION OF CHC OF TRW OUT AHEAD OF FRONT THROUGH THE EARLY MORNING. WILL ALSO BE LOWERING TEMPS FOR MINS ESP NORTH WHERE COLD ADVECTION ALREADY HAS TEMPS NEAR FORECAST MINS. && .PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 657 PM EDT WED AUG 4 2004 SHORT TERM (REST OF TONIGHT)... UPDATED TO CANCEL FF WATCH AS RUC SHOWING REMAINING OMEGA WITH SYSTEM SHOULD REMAIN TO SOUTH. WILL ADD SOME FOG TO THE EARLY MORNING HOURS. REST SAME. PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 512 PM EDT WED AUG 4 2004 SHORT TERM (REST OF TONIGHT)... UPDATED FORECAST TO SHOW THAT THE SEVERE THUNDERSTORM WATCH HAS EXPIRED. STILL MONITORING RADAR DATA TO SEE IF MOVEMENT OF THUNDERSTORM COMPLEX OVER KY AREA CONTINUES EAST. IF SO MAY DROP FLOOD WATCH WITH LATER ISSUANCE. RUC MODEL RUN SHOWS SOME FRONTAL CONVERGENCE AND LIFT STILL POSSIBLE OVER THE UPPER OHIO VALLEY...SO ANOTHER REASON TO CONTINUE FLOOD WATCH FOR NOW. WILL ALSO CONSIDER FOG PROSPECTS FOR THE NEXT ISSUANCE ALSO...ALTHOUGH WIND MAY BE TOO MUCH...AS WELL AS POSTFRONTAL DRIER AIR INFLUX. PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 312 PM EDT WED AUG 4 2004 AVIATION... SQUALL LINE APPROACHING WILL BRING RAIN AND THUNDERSTORMS TO THE AIRPORTS. SOME STORMS COULD BE SEVERE WITH STRONG WINDS... HEAVY RAIN AND HAIL. RAIN WILL CONTINUE BEHIND THE FRONT BRINGING MVFR OR IFR CONDITIONS UNTIL THURSDAY MID MORNING. SHORT TERM (THROUGH SATURDAY)... ZONES WL BE ISSUED CLOSE TO 4 PM SO I CAN CLEAR MORE OF THE TSTM WATCH. SFC LO NOT EXACTLY WHERE MODELS HAD IT. MAIN SVR WX THREAT FOR GUSTY WINDS SEEMS TO BE SPEEDING E OF PIT AS I TYPE. TSTM WATCH ALREADY CANCELLED FOR E OH. WL MENTION 70-80% POP OVERNIGHT (RAIN, CHC TSTM); THEN CONTINUE CHANCE POPS FOR AT LEAST 1ST HALF OF THU, WHILE WE WAIT FOR LARGE H5 TROF TO GET E OF CWA. NICE WEATHER FOLLOWS. TOOK AVG OF AVN-NGM-ETA TEMPS AND POPS, WHILE DOVETAILING WITH NEIGHBORS. WL KEEP FLOOD WATCH OVERNIGHT. ETA HAS HVY RAIN...SPCLY S. PARTS OF WATCH, PROB IN N, CAN BE CANCELLED (OR RE-CONSIDERED) BY EVE SHIFT. LONG TERM (SATURDAY NIGHT THROUGH TUESDAY)... MENTIONED CHC POPS MON NGT AND TUE AS NEXT SYSTEM PULLS THRU GRTLKS. OTHERWISE DRY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$ pa AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PITTSBURGH PA 657 PM EDT WED AUG 4 2004 .SHORT TERM (REST OF TONIGHT)... UPDATED TO CANCEL FF WATCH AS RUC SHOWING REMAINING OMEGA WITH SYSTEM SHOULD REMAIN TO SOUTH. WILL ADD SOME FOG TO THE EARLY MORNING HOURS. REST SAME. && .PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 512 PM EDT WED AUG 4 2004 SHORT TERM (REST OF TONIGHT)... UPDATED FORECAST TO SHOW THAT THE SEVERE THUNDERSTORM WATCH HAS EXPIRED. STILL MONITORING RADAR DATA TO SEE IF MOVEMENT OF THUNDERSTORM COMPLEX OVER KY AREA CONTINUES EAST. IF SO MAY DROP FLOOD WATCH WITH LATER ISSUANCE. RUC MODEL RUN SHOWS SOME FRONTAL CONVERGENCE AND LIFT STILL POSSIBLE OVER THE UPPER OHIO VALLEY...SO ANOTHER REASON TO CONTINUE FLOOD WATCH FOR NOW. WILL ALSO CONSIDER FOG PROSPECTS FOR THE NEXT ISSUANCE ALSO...ALTHOUGH WIND MAY BE TOO MUCH...AS WELL AS POSTFRONTAL DRIER AIR INFLUX. PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 312 PM EDT WED AUG 4 2004 AVIATION... SQUALL LINE APPROACHING WILL BRING RAIN AND THUNDERSTORMS TO THE AIRPORTS. SOME STORMS COULD BE SEVERE WITH STRONG WINDS... HEAVY RAIN AND HAIL. RAIN WILL CONTINUE BEHIND THE FRONT BRINGING MVFR OR IFR CONDITIONS UNTIL THURSDAY MID MORNING. SHORT TERM (THROUGH SATURDAY)... ZONES WL BE ISSUED CLOSE TO 4 PM SO I CAN CLEAR MORE OF THE TSTM WATCH. SFC LO NOT EXACTLY WHERE MODELS HAD IT. MAIN SVR WX THREAT FOR GUSTY WINDS SEEMS TO BE SPEEDING E OF PIT AS I TYPE. TSTM WATCH ALREADY CANCELLED FOR E OH. WL MENTION 70-80% POP OVERNIGHT (RAIN, CHC TSTM); THEN CONTINUE CHANCE POPS FOR AT LEAST 1ST HALF OF THU, WHILE WE WAIT FOR LARGE H5 TROF TO GET E OF CWA. NICE WEATHER FOLLOWS. TOOK AVG OF AVN-NGM-ETA TEMPS AND POPS, WHILE DOVETAILING WITH NEIGHBORS. WL KEEP FLOOD WATCH OVERNIGHT. ETA HAS HVY RAIN...SPCLY S. PARTS OF WATCH, PROB IN N, CAN BE CANCELLED (OR RE-CONSIDERED) BY EVE SHIFT. LONG TERM (SATURDAY NIGHT THROUGH TUESDAY)... MENTIONED CHC POPS MON NGT AND TUE AS NEXT SYSTEM PULLS THRU GRTLKS. OTHERWISE DRY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$ pa AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PITTSBURGH PA 512 PM EDT WED AUG 4 2004 .SHORT TERM (REST OF TONIGHT)... UPDATED FORECAST TO SHOW THAT THE SEVERE THUNDERSTORM WATCH HAS EXPIRED. STILL MONITORING RADAR DATA TO SEE IF MOVEMENT OF THUNDERSTORM COMPLEX OVER KY AREA CONTINUES EAST. IF SO MAY DROP FLOOD WATCH WITH LATER ISSUANCE. RUC MODEL RUN SHOWS SOME FRONTAL CONVERGENCE AND LIFT STILL POSSIBLE OVER THE UPPER OHIO VALLEY...SO ANOTHER REASON TO CONTINUE FLOOD WATCH FOR NOW. WILL ALSO CONSIDER FOG PROSPECTS FOR THE NEXT ISSUANCE ALSO...ALTHOUGH WIND MAY BE TOO MUCH...AS WELL AS POSTFRONTAL DRIER AIR INFLUX. && .PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 312 PM EDT WED AUG 4 2004 AVIATION... SQUALL LINE APPROACHING WILL BRING RAIN AND THUNDERSTORMS TO THE AIRPORTS. SOME STORMS COULD BE SEVERE WITH STRONG WINDS... HEAVY RAIN AND HAIL. RAIN WILL CONTINUE BEHIND THE FRONT BRINGING MVFR OR IFR CONDITIONS UNTIL THURSDAY MID MORNING. SHORT TERM (THROUGH SATURDAY)... ZONES WL BE ISSUED CLOSE TO 4 PM SO I CAN CLEAR MORE OF THE TSTM WATCH. SFC LO NOT EXACTLY WHERE MODELS HAD IT. MAIN SVR WX THREAT FOR GUSTY WINDS SEEMS TO BE SPEEDING E OF PIT AS I TYPE. TSTM WATCH ALREADY CANCELLED FOR E OH. WL MENTION 70-80% POP OVERNIGHT (RAIN, CHC TSTM); THEN CONTINUE CHANCE POPS FOR AT LEAST 1ST HALF OF THU, WHILE WE WAIT FOR LARGE H5 TROF TO GET E OF CWA. NICE WEATHER FOLLOWS. TOOK AVG OF AVN-NGM-ETA TEMPS AND POPS, WHILE DOVETAILING WITH NEIGHBORS. WL KEEP FLOOD WATCH OVERNIGHT. ETA HAS HVY RAIN...SPCLY S. PARTS OF WATCH, PROB IN N, CAN BE CANCELLED (OR RE-CONSIDERED) BY EVE SHIFT. LONG TERM (SATURDAY NIGHT THROUGH TUESDAY)... MENTIONED CHC POPS MON NGT AND TUE AS NEXT SYSTEM PULLS THRU GRTLKS. OTHERWISE DRY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...FLASH FLOOD WATCH FOR ZONE MDZ001 TODAY AND THURSDAY LATE MORNING. OH...FLASH FLOOD WATCH FOR ZONES OHZ039>041-048>050-057>059- 068-069 TODAY AND THURSDAY LATE MORNING. PA...FLASH FLOOD WATCH FOR ZONES PAZ007>009-013>016-020-022-023- 029>032 TODAY AND THURSDAY LATE MORNING. WV...FLASH FLOOD WATCH FOR ZONES WVZ001>004-012-021>023- 041 TODAY AND THURSDAY LATE MORNING. && $$ pa AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 815 PM MDT WED AUG 4 2004 .DISCUSSION...SCATTERED THUNDERSTORMS CONTINUE OVER NORTHEAST WYOMING. WEAK SHORTWAVE MOVING THROUGH EASTERN WYOMING WILL START TO DROP SOUTHEAST. ETA/RUC MOVE THUNDERSTORMS INTO SOUTHWEST SOUTH DAKOTA LATER THIS EVENING. OVERALL..THE CURRENT FORECAST IS IN GOOD SHAPE. WILL UPDATE IN AN HOUR OR TWO TO REMOVE EVENING WORDING. && .UNR...WATCHES/WARNINGS/ADVISORIES... .SD...NONE. .WY...NONE. $$ sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 316 AM EDT THU AUG 5 2004 .DISCUSSION... TRANQUIL WEATHER TO CONTINUE FOR A FEW DAYS. THE FCST ISSUES (AND IT IS A STRETCH TO CALL THESE FCST ISSUES) ARE TEMPS AND CLOUD COVER. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW AN AMPLIFIED EARLY AUG PATTERN. A TROF IS JUST OFF THE W COAST...A RIDGE EXTENDS FROM THE U.S. ROCKIES TO CNTRL CANADA...AND A TROF DOMINATES ERN CANADA INTO THE GREAT LAKES AND ERN CONUS. N END OF RIDGE HAS DEVELOPED INTO A WEAKLY CLOSED MID LEVEL HIGH OVER NW MANITOBA/NE SASKATCHEWAN PER 00Z RAOB ANALYSIS AT 500MB. IR AND 11-3.9 MICRON IMAGERY SHOW CLEAR SKIES DOMINATING THE UPPER GREAT LAKES. AN AREA OF STRATOCU WAS DROPPING ALMOST DUE S TOWARD ERN LAKE SUPERIOR...BUT LOOKS TO BE BREAKING UP A BIT...AND A PATCH OF CI WAS STREAMING S THRU CNTRL ONTARIO. THERE ARE NO MODEL DIFFERENCES NOTED THAT REALLY IMPACT FCST THRU SAT. UPSTREAM MID LEVEL RIDGE GRADUALLY WEAKENS AND EDGES EWD THRU SAT WITH ASSOCIATED SFC HIGH PRES MOVING FROM SRN MANITOBA TO THE WRN OHIO VALLEY. SINCE THERE WASN'T MUCH IN THE WAY OF CU UPSTREAM IN ONTARIO YESTERDAY...NOT EXPECTING MUCH HERE TODAY...ESPECIALLY OVER ABOUT THE E HALF OF UPPER MI WHERE AIRMASS WILL BE MORE STABLE DUE TO NRLY FLOW ACROSS LAKE SUPERIOR. FLOW IS LIGHTER OVER THE WRN FCST AREA SO INTERIOR SHOULD POP SCT CU WITH WEAKER STABILIZING FLOW OFF THE LAKE. TRAJECTORIES SHOW TODAYS AIRMASS ORIGINATING FROM N OF LAKE SUPERIOR WHERE HIGHS YESTERDAY WERE IN THE MID 60S TO LOW 70S. THIS SUPPORTS VARIOUS MOS GUIDANCE HERE TODAY AND AGREES WELL WITH GOING FCST. EXPECT CLEAR SKIES TONIGHT WITH INLAND AREAS CNTRL/W DECOUPLING AS SFC HIGH PRES EDGES CLOSER. TONIGHT WILL LIKELY BE THE COOLEST NIGHT ASSOCIATED WITH THIS AIRMASS. THE TYPICAL COOL SPOTS SHOULDN'T HAVE MUCH TROUBLE DROPPING TO ABOUT 40. AN OUTSTANDING FRI IS ON TAP WITH SUNNY SKIES AND LIGHT WINDS AS SFC RIDGE DRIFTS TO UPPER MI. FLOW LOOKS TO BE LIGHT ENOUGH TO ALLOW LAKE BREEZE DEVELOPMENT OFF LAKE MI W OF KISQ IN THE AFTN WHILE ONSHORE FLOW WILL DOMINATE OFF LAKE SUPERIOR GIVEN SFC RIDGE AXIS JUST TO THE W TO START THE DAY. SHOULD BE LITTLE/NO CU AS 850MB TEMPS MODERATE A BIT. SEE NO PROBLEM WITH TEMPS INLAND WELL INTO THE 70S PER GUIDANCE. WILL BE A LITTLE COOLER NEAR LAKE SUPERIOR. SFC RIDGE HOLDS OVER UPPER MI FRI NIGHT. ALTHOUGH IT WILL BE AN EXCELLENT RADIATIONAL COOLING NIGHT WITH CLEAR SKIES/CALM WIND... AIRMASS WILL HAVE MODIFIED A BIT SO TEMPS WON'T BE AS COOL AS THU NIGHT. ON SAT...ETA/GFS TAKE A SHORTWAVE THRU RIDGE TOWARD WRN GREAT LAKES WITH SHRA DRIVING THRU NRN MN. NOT EXPECTING THIS SHORTWAVE TO PRESENT ANY PCPN CONCERNS FOR UPPER MI LATER SAT OR EARLY SUN AS IT MOVES THRU RIDGE HELD IN PLACE OVER THE WRN GREAT LAKES BY STATIONARY TROF OVER THE ERN LAKES/NEW ENGLAND. COMBINATION OF WEAKENING SHORTWAVE AND DRY AIR HOLDING OVER WRN LAKES UNDERNEATH RIDGE ARGUES FOR A DRY FCST. CAN'T IMAGINE GFS WOULD VERIFY WITH PCPN MOVING INTO UPPER MI SAT NIGHT GIVEN RIDGE POSITION THAT IT SHOWS. EXPECT SOME INCREASE IN MID CLOUDS TO BE THE ONLY EFFECT OF SHORTWAVE. AIRMASS CHANGES LITTLE SO HIGHS SAT SHOULD BE SIMILAR TO FRI. NEXT SYSTEM STILL ON TRACK TO ARRIVE LATER SUN/MON WITH POTENTIAL TO GET SOME NEEDED RAINFALL IN AREAS THAT WILL HAVE BEEN DRY FOR SOME TIME. NO SIGNIFICANT TRENDS ARE NOTED IN LATEST LONGER RANGE MODEL RUNS TO SUGGEST MAKING ANY CHANGES TO GOING FCST BEYOND SAT NIGHT. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ROLFSON mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 330 AM CDT THU AUG 5 2004 .DISCUSSION...MAIN CONCERNS ARE ON TEMPS...AS LOWS THIS EVENING ACROSS NRN MINNESOTA MAY APPROACH OR EXCEED ALL-TIME RECORDS FOR THIS DATE. ISOLATED AREAS WITH FROST ARE POSSIBLE AGAIN TONIGHT WITH STRONG RADIATIONAL COOLING EXPECTED. BUILDING UL RIDGE DOMINATES CENTRAL CANADA AND N CNTRL US WITH DOWNSTREAM 75KT MAX WIND BAND HEADING SOUTHEAST ACROSS NORTHLAND. CURRENT TREND WITH RIDGE TO OUR WEST WILL CONTINUE TO BRING COOLER AIR OUR WAY TODAY AND THIS EVENING. STG 1027MB SFC HIGH CENTERED OVR SRN MANITOBA...PROVIDING A LGT NELY DRIFT TO AREA SFC WINDS. ON FRIDAY AND SATURDAY...THE HIGH WILL START TO SLOWLY DRIFT SOUTHEAST ACRS ERN WISCONSIN. THIS WILL OPEN US UP TO A RETURN SLY SEMI-MOIST FLOW FROM CENTRAL PLAINS AND GULF. INDICIES POINT TO AN AXIS OF LL CONV AHD OF TRIPLE POINT OVR ERN NEBRASKA ON SATURDAY. H5 THERMAL TROUGHING IS ALSO FORECAST TO MOVE INTO THIS AREA AT THAT TIME FOR INSTABILITY ALOFT. IN ADDITION...TOTALS TOTALS OF 49 TO 52...LIS TO -7...AND CAPES 1600 TO 1900 OVR WRN AND CNTRL MN SATURDAY AFTERNOON ALSO FAVOR CONVECTION. CURRENT TSTM FORECASTS APPEAR ON TRACK. MODEL PREFERENCES. FOCUS ON BEST INITIALIZATION WITH RUC AND SHORT RANGE GFS SOLUTIONS FOR UL FEATURES WITH 00Z RPTS...WHILE ETA AND NGM ALSO AGREE ON SFC FEATURES. LOOKING AS 00Z RAOB RPTS OVR SRN ONTARIO AND NRN MINNESOTA...00Z ETA FORECASTS H5 S/WV TROF ROTATING INTO MINNESOTA TOO DEEP. EXTENDED...A SLIGHT WARMING TREND IS IN STORE THIS WEEKEND AS PART OF UL RIDGE IS FORCED EASTWARD OVR MN. THIS WILL CAUSE HIGH TEMPERATURES TO RISE TO THE UPR 70S ACRS NRN MN. BY EARLY NEXT WEEK...AN UNSEASONABLY STRONG LOW PRESSURE SYSTEM IS FORECAST TO BRING MORE COOLER AND DRYER WEATHER TO THE NORTHLAND. AS CURRENTLY FORECAST...THE NORTHLAND WILL BE CAUGHT BETWEEN AN UPR LVL RIDGE ACRS THE INTERMOUNTAIN WEST...AND AN UPR LVL TROF ACRS THE ERN USA. THIS MEANS COOL...DRY NWLY WINDS ACRS UPR MIDWEST WITH TEMPERATURES FALLING TO SLIGHTLY BELOW NORMAL FOR AUGUST. .DLH...WATCHES/WARNINGS/ADVISORIES MN...NONE. WI...NONE. $$ TRIPOLI mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 300 AM CDT THU AUG 5 2004 .DISCUSSION... STRATUS HAS BEEN ERODING EARLY THIS MORNING AS DRIER AIR ADVECTS IN FROM THE NORTHEAST. MID LEVEL COLD ADVECTION HAS ALSO AIDED IN THE EROSION OF THE LOW CLOUD DECK BY EATING INTO THE INVERSION LAYER ABOVE THE STRATUS. THE RUC MODEL SIMULATED THE LOW LEVEL ATMOSPHERIC PROFILE THE BEST DURING THIS UNUSUAL EARLY AUGUST STRATUS EVENT. USING THE RUC FORECAST SOUNDINGS AND 925MB RELATIVE HUMIDITIES, THE LOW CLOUD DECK SHOULD BE ERODED IN ALL BUT THE PAOLA AND BUTLER AREAS BY SUNRISE. WITH THE EXCEPTION OF SOME CIRRUS BLOW OFF FROM STORMS ON THE HIGH PLAINS THE FORECAST AREA SHOULD ENJOY MOSTLY SUNNY SKIES TODAY. TEMPERATURES WILL DROP TO NEAR RECORD LEVELS TONIGHT. KANSAS CITY'S RECORD LOW IS 55 DEGREES (1990) AND SAINT JOSEPH'S IS 54 DEGREES (ALSO 1990). ONE MUST LOOK TO SOUTHERN MINNESOTA AND WISCONSIN TO FIND LOW TO MID 50S DEWPOINTS ON THIS MORNING'S SURFACE CHART. GETTING THIS DRY AIR INTO NORTHWEST MISSOURI, FOR OPTIMAL RADIATIONAL COOLING, MAY BE TOUGH WITH RELATIVELY MOIST SOIL CONDITIONS IN THE REGION. CIRRUS BLOW OFF FROM STORMS ON THE HIGH PLAINS TONIGHT MAY ALSO IMPEDE RADIATIONAL COOLING SOMEWHAT. SAINT JOSEPH WILL PROBABLY HAVE A BETTER SHOT TO BREAK THE RECORD TONIGHT SINCE THE ASOS SITS IN THE MISSOURI RIVER VALLEY. WINDS THERE WILL LIKELY DECOUPLE EARLY THIS EVENING. THE SENSOR AT MCI SITS CONSIDERABLY HIGHER IN ELEVATION AND WILL LIKELY ENDURE AN EAST WIND AROUND 5KTS ALL NIGHT LONG. COOL SURFACE HIGH PRESSURE WILL RESIDE OVER THE MIDWEST THROUGH THE EARLY PART OF THE WEEKEND. AN AREA OF LOW PRESSURE OFF THE COAST OF THE PACIFIC NORTHWEST WILL ULTIMATELY TRACK INTO THE NORTHERN PLAINS ON SUNDAY AND DISLODGE IT. GULF MOISTURE WILL BE SLOW TO RETURN TO THE CENTRAL AND SOUTHERN PLAINS ON SUNDAY NIGHT AND MONDAY AS THE COLD FRONT ASSOCIATED WITH THE AFOREMENTIONED UPPER LOW TRACKS INTO THE REGION. THE ECMWF AND GFS ARE SIMILAR WITH THE TIMING OF THESE FEATURES, BUT MOISTURE RETURN WILL DETERMINE WHETHER CONVECTION WILL BE ISOLATED OR WIDESPREAD WITH FRONTAL PASSAGE EARLY NEXT WEEK. FOR NOW WE HAVE ONLY 30 TO 40 PERCENT CHANCES FOR THUNDERSTORMS ON SUNDAY AND MONDAY. KOCH && .PREV DISCUSSION... 1030 PM WED... DOING A QUICK REVISION TO RAISE MINS A BIT TONIGHT. DEWPOINTS NOT DROPPING AS MUCH AS EXPECTED. MAY ALSO SEE SOME AREAS OF FOG IF WINDS DROP OFF MORE THAN EXPECTED. WILL NOT MENTION AT THIS POINT...BUT SOMETHING TO WATCH OUT FOR. PC && 328 PM WED... SURFACE FRONT ALMOST THROUGH ENTIRE FORECAST AREA THIS AFTERNOON...MOVING SLOWLY IN THE SOUTHEAST CORNER. SHOULD BE THROUGH KDMO IN THE NEXT COUPLE OF HOURS. FROPA IS ASSOCIATED WITH A FEW SPRINKLES AND A LOW DECK OF STRATUS. BEHIND THE FRONT THE CLOUD DECK HAS SLOWLY RAISED...WITH SOME BREAKS IN NORTHERN MISSOURI. FORECAST TONIGHT IS CONCERNED CLOUDS AND TEMPS. IF UPSTREAM IS ANY INDICATION...SHOULD SEE BROKEN CLOUDS THROUGH MUCH OF THE EVENING. SHOULD SEE SOME CLEARING AFTER MIDNIGHT. AVE NOT INCLUDED ANY FOG IN THE GRIDS OR THE TAFS...BUT AS TEMPS DROP NEAR THE DEWPOINT /LOWER 60S/ IT IS POSSIBLE. MAY SEE CEILINGS BRIEFLY DROP TO 1000FT AND 3-5SM. HAVE PUT LOWS JUST A DEG OR TWO UNDER GUIDANCE. H8 TEMPS FOR THURSDAY DROP TO AROUND +13. SHOULD SEE SOME CU DEVELOP...SO HAVE KEPT HIGHS RIGHT AROUND 80 WHICH IS NEAR THE PREV FORECAST AND MET GUID. SURFACE HIGH PRESSURE IN CONTROL FOR THE REST OF THE WORK WEEK WITH A MINOR WARMING TREND TO ENSUE. GOING INTO THE WEEKEND...SEASONALLY NORMAL TEMPERATURES WILL TRY TO REASSERT THEMSELVES AS THE RIDGE OVER THE DESERT SOUTHWEST AMPLIFIES AND TRAVERSES EAST INTO THE PLAINS STATES. LATE IN THE WEEKEND AND EARLY NEXT WEEK A LOW OVER THE EAST COAST WILL LIFT THROUGH THE ST LAWRENCE RIVER VALLEY...WHILE AN EAST PACIFIC LOW BEATS DOWN THE MIDWEST RIDGE AND ALLOWS STILL MORE UNSEASONABLY COOL AIR TO FILTER SOUTH. THE MODELS ARE NOT IN COMPLETE AGREEMENT WITH HOW MUCH COOL AIR WILL WORK SOUTH. THE GFS IS SLOWER TO LIFT THE EAST COAST LOW THROUGH THE ST LAWRENCE VALLEY. THIS WOULD ALLOW THE SHORTWAVE...THAT IS FORECAST TO BEAT THE RIDGE DOWN...A CHANCE TO CARVE OUT A DEEP TROUGH ACROSS THE MIDWEST. THUS...PUSHING A DECENT COLD FRONT THROUGH MISSOURI SUNDAY/MONDAY. THE ECMWF AND UKMET ARE A LITTLE FASTER WITH LIFTING THE EAST COAST LOW...WHICH ULTIMATELY DOES NOT ALLOW AS MUCH TROUGHING ACROSS THE MIDWEST...AND THEREFORE INDICATES A MUCH WEAKER FRONTAL PASSAGE SUNDAY NIGHT. THE GFS LOOKS TO BE SUFFERING FROM SOME CONVECTIVE FEED BACK PROBLEMS WITH THE SHORTWAVE THAT IS PROGGED TO CARVE OUT NEXT WEEKS TROUGH...WHICH LEADS ONE TO THINK THAT THIS IS LEADING TO THE ANONYMOUSLY STRONG TROUGH SOLUTION. THEREFORE...I MADE MY ADJUSTMENTS TO THE GOING FORECAST BASED ON THE ECMWF SOLUTION. I PUSHED UP THE FRONTAL PASSAGE ENOUGH TO WARRANT STICKING THUNDERSTORMS INTO SUNDAY NIGHT...WHILE KEEPING THEM IN THE EAST CWA FOR MONDAY. OTHERWISE...I ONLY MADE MINOR MODIFICATIONS TO TEMPERATURES NEXT WEEK BY COOLING THINGS OFF A LITTLE...BUT KEPT TEMPS WARMER THAN THE MEX GUIDANCE. LVQ/CUTTER && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ WFOEAX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1150 AM EDT THU AUG 5 2004 .DISCUSSION... LARGE RIDGE OF HIGH PRES CENTERED JUST NW OF LK SUPERIOR IS PROVIDING UPR GREAT LAKES MAINLY SUNNY SKIES AND DRY WX. ONLY CONCERN FOR UPDATE IS WIND SPEEDS OVR E ZONES. SFC HIGH SHOULD DRIFT SSE THIS AFTN SO N GRADIANT WIND PRESENTLY OVR UPR MI WILL CONTINUE...EXCEPT IN FAR W ZONES AS LIGHTER WINDS WITH HIGH PRES SLIDE OVERHEAD. E ZONES WITHIN STRONGEST GRADIANT FLOW AND WITHIN AREA OF SLIGHT COLD AIR ADVECTION FM NE. ADDITIONALLY...THE CWCZ SOUNDING ON S SHORE OF JAMES BAY (MOOSONEE ONTARIO) SHOWS 25-30KT WINDS FM 925MB-850MB AND THIS SWINGS OVR FAR SE LK SUPERIOR AND ALGER/LUCE/N SCHOOLCRAFT COUNTIES THIS AFTN. RUC FORECAST SOUNDING FOR KERY THIS AFTN SHOWS MIXED LAYER WINDS REACHING TOWARD 25 KT. CONSIDERING THE SPEED MAX MOVING IN...THINK THIS MAKES SOME SENSE SO BUMPED WINDS TO BREEZY FOR THOSE ZONES. OTHERWISE...FORECAST GRIDS IN GREAT SHAPE SO NO CHANGES WERE NEEDED. UPDATED/PUBLISHED GRIDS AND UPDATE TEXT ZFPMQT ALREADY OUT. JLA .PREV DISCUSSION (ISSUED 316 AM EDT THIS MORNING)... EXPECT CLEAR SKIES TONIGHT WITH INLAND AREAS CNTRL/W DECOUPLING AS SFC HIGH PRES EDGES CLOSER. TONIGHT WILL LIKELY BE THE COOLEST NIGHT ASSOCIATED WITH THIS AIRMASS. THE TYPICAL COOL SPOTS SHOULDN'T HAVE MUCH TROUBLE DROPPING TO ABOUT 40. AN OUTSTANDING FRI IS ON TAP WITH SUNNY SKIES AND LIGHT WINDS AS SFC RIDGE DRIFTS TO UPPER MI. FLOW LOOKS TO BE LIGHT ENOUGH TO ALLOW LAKE BREEZE DEVELOPMENT OFF LAKE MI W OF KISQ IN THE AFTN WHILE ONSHORE FLOW WILL DOMINATE OFF LAKE SUPERIOR GIVEN SFC RIDGE AXIS JUST TO THE W TO START THE DAY. SHOULD BE LITTLE/NO CU AS 850MB TEMPS MODERATE A BIT. SEE NO PROBLEM WITH TEMPS INLAND WELL INTO THE 70S PER GUIDANCE. WILL BE A LITTLE COOLER NEAR LAKE SUPERIOR. SFC RIDGE HOLDS OVER UPPER MI FRI NIGHT. ALTHOUGH IT WILL BE AN EXCELLENT RADIATIONAL COOLING NIGHT WITH CLEAR SKIES/CALM WIND... AIRMASS WILL HAVE MODIFIED A BIT SO TEMPS WON'T BE AS COOL AS THU NIGHT. ON SAT...ETA/GFS TAKE A SHORTWAVE THRU RIDGE TOWARD WRN GREAT LAKES WITH SHRA DRIVING THRU NRN MN. NOT EXPECTING THIS SHORTWAVE TO PRESENT ANY PCPN CONCERNS FOR UPPER MI LATER SAT OR EARLY SUN AS IT MOVES THRU RIDGE HELD IN PLACE OVER THE WRN GREAT LAKES BY STATIONARY TROF OVER THE ERN LAKES/NEW ENGLAND. COMBINATION OF WEAKENING SHORTWAVE AND DRY AIR HOLDING OVER WRN LAKES UNDERNEATH RIDGE ARGUES FOR A DRY FCST. CAN'T IMAGINE GFS WOULD VERIFY WITH PCPN MOVING INTO UPPER MI SAT NIGHT GIVEN RIDGE POSITION THAT IT SHOWS. EXPECT SOME INCREASE IN MID CLOUDS TO BE THE ONLY EFFECT OF SHORTWAVE. AIRMASS CHANGES LITTLE SO HIGHS SAT SHOULD BE SIMILAR TO FRI. NEXT SYSTEM STILL ON TRACK TO ARRIVE LATER SUN/MON WITH POTENTIAL TO GET SOME NEEDED RAINFALL IN AREAS THAT WILL HAVE BEEN DRY FOR SOME TIME. NO SIGNIFICANT TRENDS ARE NOTED IN LATEST LONGER RANGE MODEL RUNS TO SUGGEST MAKING ANY CHANGES TO GOING FCST BEYOND SAT NIGHT. ROLFSON && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BUFFALO NY 948 AM EDT THU AUG 5 2004 .UPDATE...A COUPLE OF STRAY SHOWERS DEVELOPED EARLIER THIS MORNING ACROSS THE SOUTHERN TIER BUT ARE JUST ABOUT TO EXIT THE SOUTHEAST CORNER OF CATTARAUGUS COUNTY INTO PENNSYLVANIA. CURRENT VISIBLE SATELLITE LOOP INDICATING EXTENSIVE CLOUDINESS SOUTH OF BUFFALO AND ROCHESTER BUT WITH MUCH DRIER DEW POINTS ADVECTING IN FROM THE NORTH WE DO EXPECT AT LEAST PARTIAL SUNSHINE DOWN SOUTH AND MORE SUN THAN CLOUDS ACROSS THE NIAGARA FRONTIER. FORECAST TEMPERATURES LOOK REASONABLE AT THIS TIME. SOME WORDING CHANGES FOR THIS AFTERNOON INVOLVING SKY COVER BUT THAT WILL BE IT FOR THIS UPDATE. EARLIER AFD BELOW ALTHOUGH A MARINE SECTION HAS BEEN ADDED. && .SHORT TERM (TODAY THROUGH SATURDAY)...HIGH PRESSURE CENTERED OVER LAKE WINNIPEG WILL DRIFT SLOWLY TO THE SOUTHEAST AND BRING A REINFORCING SHOT OF UNSEASONABLY COOL AIR TO THE FA FOR THE NEXT TWO TO THREE DAYS. IN THE SHORT TERM...THE CLOUDS WILL CONTINUE TO THIN OUT FROM WEST TO EAST AS THE NEW JERSEY LOW AND ITS TRAILING COLD FRONT SLIDE OFF THE COAST THIS MORNING. COLD AIR ADVECTION BEHIND THE FRONT WILL DROP H8 TEMPERATURES TO ABOUT 7C THIS AFTERNOON. CORRESPONDING SURFACE TEMPERATURES WILL REBOUND TO AROUND 70. AS THE COLDER AIR DEEPENS ACROSS THE FA TONIGHT...TEMPERATURES WILL GET COLD ENOUGH TO GENERATE SOME LAKE EFFECT CLOUDS AND MAYBE EVEN A FEW SHOWERS SOUTH OF LAKE ONTARIO...ESPECIALLY ACROSS MONROE AND WAYNE COUNTIES WHERE THE MESO-ETA LOW LEVEL OMEGA FIELDS AND INSTABILITY ARE STRONGEST. SCATTERED SHOWERS WILL BECOME A BIT MORE WIDESPREAD FRIDAY AS THE UPPER LEVEL TROUGH CLOSES OFF OVER NEW YORK STATE AND NEW ENGLAND. THE ETA SHOWS A WELL DEFINED SHORT WAVE ROTATING SOUTH ACROSS NEW YORK STATE FRIDAY NIGHT AND SATURDAY. WILL LEAVE IN CHANCE POPS ACROSS THE ENTIRE AREA DURING THIS PERIOD AS THE UPPER LEVEL IMPULSE MOVES SOUTH. SOME LAKE ENHANCED PCPN WILL ONCE AGAIN BE SEEN ACROSS PARTS OF THE LOWER GENESEE VALLEY AND WESTERN FINGER LAKES FRIDAY NIGHT IN THE COOL...UNSTABLE NORTHWEST FLOW. DAYTIME HIGH TEMPERATURES WILL HAVE A TOUGH TIME GETTING OUT OF THE 60S FRIDAY AND SATURDAY AS H8 TEMPERATURES HOVER AROUND 5C. && .LONG TERM (SUNDAY AND BEYOND)...TEMPERATURES WILL BEGIN TO MODERATE ON SUNDAY AS THE CENTER OF THE COLDEST AIR ALOFT SHIFTS INTO NEW ENGLAND...AND DRIER AIR BEGINS TO WORK ITS WAY INTO REGION. DECIDED TO KEEP SUNDAY DRY FOR NOW, EVEN THOUGH A SCATTERED SHOWER WOULD NOT BE OUT OF THE QUESTION. UPPER RIDGING AND A FURTHER MODERATION IN TEMPERATURES EXPECTED MONDAY. MRF SHOWS YET ANOTHER UPPER LOW MOVING ACROSS THE GREAT LAKES MONDAY NIGHT AND TUESDAY. CHC POPS WERE RETAINED FROM EARLIER FCST. && .AVIATION... SKIES HAVE GENERALLY CLEARED EARLY THIS MORNING FOLLOWING THE COLD FRONTAL PASSAGE BUT PATCHY FOG IS REDUCING VISIBILITIES SIGNIFICANTLY WITH LOCAL IFR CONDITIONS AT KBUF, KIAG AND KROC UNTIL ABOUT 11Z. LOOK FOR VFR CONDITIONS TO THEN PREVAIL WITH SCATTERED TO BROKEN CEILINGS IN THE 3 TO 4 K FT RANGE THURSDAY AFTERNOON AND EVENING. && .MARINE... BUOYS STILL SHOW WINDS FROM 15 TO 20 KNOTS ON LAKE ONTARIO...WITH A FEW GUSTS JUST ABOVE 20 KNOTS. WAVES HAVE STARTED TO DIMINISH...BUT MID LAKE BUOY STILL SHOWS WAVES JUST OVER 3 FEET...SO STILL EXPECT SOME 4-FOOT WAVES ON THE NORTHERLY FETCH TOWARD THE SOUTH SHORE. WILL CONTINUE SMALL CRAFT ADVISORIES INTO THE EARLY AFTERNOON. MAY BE ABLE TO DISCONTINUE THE ADVISORIES EARLY IN THE AFTERNOON PARTICULARLY SOUTHWEST AS WINDS BACK MORE TO THE NORTHWEST AS FORECAST BY THE RUC AND MESOETA. AS FOR LAKE ERIE...WIND SPEEDS ARE ABOUT THE SAME AS ON LAKE ONTARIO AT THE BUOY BUT ARE LESS AT THE DKK CMAN. BUOY OBSERVATIONS SHOW THE WAVES ARE NOT RESPONDING AS ON LAKE ONTARIO. WILL CONTINUE UNDER SMALL CRAFT BUT WITH THE NORTHEAST WINDS BACKING NORTH WILL INCREASE WAVES TO 2 TO 4 FEET. && .HYDROLOGY... WEDNESDAY'S RAINFALL WAS LIGHT...IN THE ORDER OF 0.25 TO 0.5 INCH ACROSS THE SOUTHERN TIER AND LESSER AMOUNTS ELSEWHERE. THERE WERE NO IMPACTS ON ANY RIVERS OR CREEKS. SOIL MOISTURE CONTINUES ABOVE NORMAL FOR EARLY AUGUST. NO SIGNIFICANT QPF IN STORE FOR THE NEXT SEVERAL DAYS. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...SMALL CRAFT ADVISORIES IN EFFECT THIS AFTERNOON FROM THE NIAGARA RIVER TO SODUS BAY. $$ UPDATE...SAGE SHORT TERM/LONG TERM...TJP/PO MARINE...DJF AVIATION...SFM ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 945 AM EDT THU AUG 5 2004 .DISCUSSION... WILL UPDATE FORECAST TO BUMP UP CHANCE OF TSTMS A LITTLE. MODEL SOUNDING FROM THE RUC AND MESOETA ARE SHOWING K INDEX ABOVE 30 AND CAPES AROUND 3000J/KG ESPECIALLY ALONG AND EAST OF US1. THINKING IS SHOWERS AND TSTM ACTIVITY IS LIKELY OVER THE EASTERN HALF OF THE AREA. WITH HIGH CAPES DAMAGING WINDS WILL LIKELY BE A PROBLEM LATER THIS AFTERNOON ALONG WITH SOME HAIL. THE THETA E DIFFERENCE IF THE LOWERS 300 MB IS AROUND 42 DEGREES CELSIUS WHICH SHOULD SUPPORT STRONG TSTM WIND GUSTS. THE WET BULB ZERO IS RUNNING BETWEEN 10KFT TO 13 KFT AND THIS SHOULD LIMIT LARGE HAIL THOUGH SMALL HAIL UP TO NICKEL SIZE IS POSSIBLE. WILL NOT RAISE HEAT ADVISORY BUT HEAT INDICES OVER THE COASTAL PLAIN FROM SMITHFIELD TO GOLDSBORO...LILLINGTON...FAYETTEVILLE AND LAURINBURG WILL APPROACH 105. && .AVIATION... SOUTHWEST FLOW OVER THE AREA WILL INCREASE AS A COLD FRONT APPROACHES FROM THE NORTHWEST AND WEST. THE COLD FRONT WILL MOVE ACROSS THE AREA DURING THE AFTERNOON BRINGING WITH IT A CHANCE OF SHOWERS AND THUNDERSTORMS. VFR CIGS AND VSBYS...EXCEPT MVFR TO OCNLY IFR VSBYS IN BR AND HZ THROUGH 13Z...18Z TO 24Z CONDITIONS LOWERING TO MVFR CIGS AND VSBYS IN SCATTERED SHOWERS AND THUNDERSTORMS. && .RAH WATCHES/WARNINGS/ADVISORIES... NC...NONE. && $$ JO nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 940 AM EDT THU AUG 5 2004 LATEST SURFACE ANALYSIS SHOWS FRONT MAKING SOUTHWARD PROGRESS THIS MORNING...CURRENTLY ALIGNED WSW-ENE FROM AROUND DANVILLE VA TO PETERSBURG TO JUST SOUTH OF MELFA. MEANWHILE...MOSAIC RADAR LOOPS SHOW SHOWERS/EMBEDDED TSTMS BLOSSOMING ACROSS SRN WVA AND FAR SRN VA. THE AREA OF PRECIP IS POST-FRONTAL AND ASSOCIATED WITH INCREASING RRQ JET REGION (FRONTOGENETIC) FORCING. IN RESPONSE TO THIS INCREASING UPPER LEVEL DIVERGENCE (850-500 MB QVECTOR CONVERGENCE) BOTH THE RUC AND GFS PICK UP ON A DEVELOPING SURFACE LOW ALONG THE FRONT LATER THIS AFTN...OVER CEN NC PER THE RUC AND NRN SC PER THE GFS. MEANWHILE...THE GFS BECOMES QUITE BULLISH THIS EVENING WITH THE DEGREE OF RRQ JET REGION UPPER DIVERGENCE AND LOW-MID LEVEL LIFT. THUS GOOD RAINFALL POTENTIAL N OF THE SURFACE LOW (COOL SIDE OF FRONT) WITH THE ERLY OR ONSHORE LOW LEVEL FLOW...RESEMBLING A COOL SEASON EVENT WITH GOOD WAA/MOIST ISENTROPIC ASCENT NOTED. GIVEN THE AMOUNT OF RAIN WE'VE HAD OF LATE...THIS IS SOMETHING THAT WILL BEAR WATCHING FOR AREAS OVER SERN VA/NERN NC. OTHERWISE...IN TERMS OF THE SEVERE WEATHER THREAT...CONTINUE TO EXPECT RISK PRIMARILY OVER SERN VA/NERN NC S OF THE FRONT...WHERE LESS CLOUD COVER CURRENTLY WILL RESULT IN THE MOST SURFACE DESTABILIZATION. MODIFIED RUC MODEL SOUNDING FOR A 90/74 TEMP/DWPT REGIME YIELDS SBCAPES AROUND 3000 J/KG AND LIFTED INDICES AROUND -7C. TOTAL-TOTAL INDICES IN THE LOWER 40S ARE INDICATIVE OF WEAK LAPSE RATES ALOFT (ONLY 5.5 C/KM BTWN 700/500 MB). HOWEVER...GOOD DRYING ALOFT IS NOTED CURRENTLY OVER THIS REGION...WITH 700 MB DEWPOINT DEPRESSIONS AROUND 10C AND 850-700 MB THETA-E LAPSE RATES AROUND 15C. THIS WOULD PROMOTE AN INCREASED DOWNBURST THREAT WITH TSTMS LATER THIS AFTERNOON...ALONG WITH A HAIL THREAT AS THE MODEL RUC SOUNDING WET BULB ZERO LEVEL (AROUND 11 KFT) FALLS WELL BELOW THE FREEZING LEVEL (14-14.5 KFT). WILL UPDATE THE SEVERE WEATHER OUTLOOK TO REFLECT THE CURRENT THINKING IN TERMS OF TIMING AND SEVERE WEATHER TYPE(S). MARINE FORECAST...AS WE EXPECT SMALL CONDITIONS TO DEVELOP OVER THE NEXT 12 HRS...WILL HOIST A SCA FOR CHES BAY FROM SMITH POINT SOUTH AND OVER THE NRN COASTAL WATERS FROM FENWICK ISLAND TO CHINCOTEAGUE. UPDATED FORECASTS WILL BE OUT BY 11 AM. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SCA CSTL WATERS FROM FENWICK ISLAND DE TO CHINCOTEAGUE VA. SCA CHES BAY FROM SMITH POINT TO CAPE HENRY. && PREVIOUS AFD BELOW... -------------------------------------------------------------------- .SHORT TERM (TODAY THROUGH FRIDAY)... ENJOYED SUMMERY WX CONDS YDA...HWVR THEY APR TO BE SHORT-LIVED. UNUSUALLY STRNG UPR LVL TROF FOR THE SEASON DVLPS OVR THE ERN STATES HEADING INTO THE WKND...BRINGING A PREVIEW OF ERY FALL (AT LEAST FOR A CPL OF DAYS). ONE AREA OF CNVTN CURRENTLY PUSHING THRU DE...BRUSHED XTRM NRN DORCHESTER CTY ABT AN HR AGO...OTRW NO PCPN OVR FA ATTM. NEXT BATCH OF CNVTN W OF MTNS OVR KY/TN...WHICH HAS BEEN SHOWING SIGNS OF WKNG PAST FEW HRS. SFC CDFNT FM SCNTRL NEW ENG TO SRN IN PRESSES SLOLY SE TDA...REACHING THE NC/VA BRDR THIS EVE. LLVL FLO TURNS FM SW TO NNW AS FNT APPROACHES/PUSHES INTO FA FM NW TO SE TDA. NOT REALLY SURE ABT AMT OF CVRG FOR CNVTN TDA GIVEN UNFAVORABLE LLVL FLO PTRN. GFS/ETA HV SIMILAR TMG OF FNT TDA...WHR THEIR DIFFS LIE IS TNGT THRU FRI. GFS MUCH SHARPER W/ TROF ALOFT...AND DVLPS MR SGFNT LO PRES ON FNT NR VA CAPES TNGT WHICH MVS UP THE CST AS TROF AMPLIFIES FRI INTO SAT (A TYPICAL WINTER STM PTRN...NOT COMMONLY SEEN AT THIS TM OF YR)...WHL ETA SIMPLY PUSH MUCH WKR WV OFF MDATLC CST LTR TNGT...AND DRIVES SGFNT DRYING INTO RGN FM. OVRALL PTRN QUITE ANOMALOUS FOR THIS TM OF YR...AND WOULD NOT TOTALLY RULE OUT THE STORMIER GFS SOLN...WHICH WOULD MEAN UNSETTLED CONDS LINGER INVOF CST THRU GOOD BIT OF FRI...ALG W/ STRNGR LLVL CAA IN THE STMS WAKE ELSW. FOR NOW...HV COMPROMISED...GOING LIKELY POPS SE ERY TNGT...OTRW CHC...WHL MVG PCPN SLOER OUT OF THE AREA BY LT TNGT/ERY FRI...AND KPG MR IN THE WAY OF CLDNS ENE SXNS INTO FRI AFTN. && .LONG TERM (FRIDAY NIGHT THROUGH WEDNESDAY)... REFRESHINGLY COOL CONDS XPCTD FRI NGT INTO SAT MORNING. LO TEMP RCRDS MAY BE CHALLENGED (SEE CLIMATE SXN BLO FOR DETAILS). MID/UPR LVL TROF SLO TO EXIT SAT...WHICH WL KP TEMPS NRLY 10 DEGS F BLO NRML ALL AREAS. SFC HI PRES REACHES THE CST BY SUN AFTN/NGT...LEADING TO RETURN FLO FM SW (AND WRMG). RCRD LO TEMPS MAY AGAIN BE CHALLENGED SAT NGT UNDER SKC/NR CALM CONDS. NEXT FNTL BNDRY APPROACHES ARND MID NEXT WK. && .AVIATION... MVFR CONDS IN SCTD CNVTN TDA INTO TNGT. && .MARINE... NO SGFNT WX XPCTD TDA INTO ERY TNGT (OTR THAN SCTD CNVTN). LLVL CAA SURGE XPCTD LT TNGT INTO FRI...LEADING TO INCRSG N WNDS AND SEAS (TO SCA CRITERIA). CONDS COULD GET QUITE ROUGH SHOULD STRNGR GFS SFC LO JUST OFF THE CST VERIFY LT TNGT THRU FRI...SOMETHING TO WATCH FOR IN IN THE NEXT 24 HRS. && .HYDROLOGY... SEBRELL AND FRANKLIN THREATENING MINOR FLDG. MODERATE RAINFALL MAY BRING BRIEF RISES ALL AREAS...OTRW...CONDS SHOULD IMPRV THRU THE WKND/ERY NEXT WK DUE TO PD OF DRY WX. && .CLIMATE... RECORD LOWS SAT-SUN SAT AM 8/7 SUN AM 8/8 RIC 53/1933 57/2002 ORF 59/1948 60/1950 SBY 50/2002 48/2002 ECG 53/1957 55/1995 && $$ SHORT TERM/LONG TERM...25 AVIATION/MARINE...32 va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 116 PM MDT THU AUG 5 2004 .SHORT TERM (TONIGHT THROUGH FRIDAY NIGHT)... AS A SURGE OF MONSOON RELATED SHOWERS AND MINOR VORT MAX MOVE NE THROUGH THE NORTHEAST PORTION OF THE CWA...A SECOND SURGE/VORT MAX IS MOVING TOWARD THE FOUR CORNERS FROM AZ. RUC AND MESOETA SHOW THIS SECOND SURGE TO SLIDE A BIT FURTHER TO THE SOUTH THIS EVEING THAN DID THIS MORNING'S PRECIPITATION AREA. THE PATCH OF CLEARING BETWEEN THE TWO SURGES IS ALLOWING ENOUGH SURFACE HEATING TO KICK OFF SCATTERED THUNDERSTORMS OVER THE LA SALS AND ABAJOS MTNS AND SW CO. HAVE INCREASED AREAL COVERAGE OF SHOWERS AND THUNDERSTORMS FOR THE REST OF THIS AFTERNOON AND THIS EVENING. OVERNIGHT PRECIPITATION SHOULD ALLOW FOR COOLER MIN TEMPS AS SHOWN IN MODEL GUIDANCE AND CURRENT FORECAST. ON FRIDAY...HIGH PRESSURE CENTERED OVER NM WILL SHIFT WEST TO AZ... CAUSING THE FLOW ALOFT TO SHIFT FROM SW TO NW EVENTUALLY. THIS IS A MUCH DRIER PATH. CLEARER SKIES AND WARM ADVECTION WILL ALLOW MAX TEMPS TO RECOVER 5-10 DEGREES OVER TODAY'S MAXES. ENOUGH MOISTURE WILL REMAIN FOR SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS MAINLY OVER THE MOUNTAINS. .LONG TERM (SATURDAY THROUGH THURSDAY)... SATURDAY...THE CENTER OF THE HIGH SLIDES FARTHER WEST, NEAR THE AZ/NM/MEXICO BORDER. THIS WILL EFFECTIVELY SHUT OF MOISTURE TO THE SOUTHWEST, ALTHOUGH SOME RESIDUAL MOISTURE WILL BE IN PLACE. FLOW ALOFT BECOMES MORE WESTERLY, AND A FEW WAVES IN THE FLOW WILL ALLOW FOR SOME AFTERNOON, TERRAIN-DRIVEN CONVECTION (MAINLY SOUTH). LARGER LOW CENTER MONTANA/SASKATCHEWAN BORDER TOO FAR NORTH TO HAVE MUCH EFFECT ON CWA. TEMPERATURES CLOSE TO NORMAL. SUNDAY THROUGH THURSDAY...DRYING TREND CONTINUES THROUGHOUT THE PERIOD. HIGH PRESSURE REMAINS TO OUR SOUTHWEST, WHILE LOW PRESSURE CENTERS NEAR THE GREAT LAKES AND OFF THE PACIFIC NORTHWEST COAST INDUCE A LARGE RIDGE OVER THE WESTERN U.S. FLOW ALOFT WILL BECOME MORE NORTHWEST. ONLY ISOLATED (MAINLY DRY) DIURNAL MOUNTAIN THUNDERSTORMS ARE EXPECTED. DRY ELSEWHERE WITH TEMPERATURES SLIGHTLY ABOVE NORMAL. && .GJT WATCHES/WARNINGS/ADVISORIES... .CO...NONE. .UT...NONE. $$ CJC/BA co AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE MARQUETTE MI 359 PM EDT THU AUG 5 2004 .DISCUSSION... DRY WEATHER TO CONTINUE FOR AT LEAST A FEW MORE DAYS...THEN NEXT CHC OF RAIN SUN AFT INTO MON. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW AN AMPLIFIED PATTERN WITH A TROF OFF THE W COAST...A RIDGE OVER THE U.S WRN PLAINS INTO CNTRL CANADA...AND A TROF OVER ERN CANADA INTO THE LOWER GREAT LAKES. A WEAK SHRTWV TOPPING THE RDG OVER THE CNTRL CONUS HAS DEVELOPED CONVECTION IN WAA REGIME OVER THE DKTAS. VISIBLE SATELLITE SHOWS AND PLENTY OF SUNSHINE FROM MANITOBA AND WRN ONTARIO INTO THE UPPER GRT LAKES AS SFC HIGH DOMINATES. EXPECT CLEAR SKIES TONIGHT WITH INLAND AREAS CNTRL/W DECOUPLING AS SFC HIGH PRES DRAWS NEAR. UPSTREAM TEMPS LAST NIGHT OVER NRN MN DROPPED INTO THE MID 30S UNDER THE SFC RDG AXIS SO WOULD EXPECT SOME MID 30S TO BE REACHED OVER THE COOLER INTERIOR LOCATIONS OF THE WEST CLOSER TO WHERE THE RDG AXIS IS FCST TO BE LATER TONIGHT. THE ERN HALF OF THE FCST AREA WILL SEE A LGT NNW GRAD WIND AHEAD OF THE RDG. THIS LIGHT MIXING SHOULD KEEP TEMPS IN INTERIOR EAST FROM FALLING MUCH BELOW MID 40S...IN LINE WITH 12Z MOS GUIDANCE. MID-LVL RIDGE BUILDS IN MORE OVER THE AREA AS 850 MB TEMPS RISE TO 10-12C. LIGHT WIND WILL ALLOW FOR LAKE BREEZE DEVELOPMENT OFF LAKE MI WHILE ONSHORE FLOW WILL DOMINATE OFF LAKE SUPERIOR GIVEN SFC RIDGE AXIS JUST TO THE W. KEPT FAIRLY CLOSE TO GFS GUIDANCE TEMPS WITH INLAND SPOTS REACHING LOW 70S NORTH AND EAST AND UPPER 70S ALONG THE WI BDR. WILL BE A LITTLE COOLER NEAR THE LAKE SUPERIOR SHORE WHERE HIGHS WILL BE IN THE UPPER 60S. ALTHOUGH SFC RIDGE HOLDS OVER UPPER MI FRI NIGHT AND RADIATIONAL COOLING SHOULD BE IDEAL...MODIFIED AIRMASS FROM FRIDAY'S DIURNAL HEATING AND SUBSIDENCE WARMING SHOULD RESULT IN SLIGHTLY WARMER INLAND MIN TEMPS...MID 40S. ON SAT...A WEAK SHORTWAVE RIPPLES THRU THE UPR RIDGE INTO THE WRN GREAT LAKES PER GFS AND TO LESSER EXTENT ETA. GIVEN DRY AIRMASS IN PLACE...EXPECT LTL MORE THAN MID-LVL CLDS FROM THIS FEATURE AND THIS AGREES WITH MODEL QPF FIELDS. HIGHER 850 MB TEMPS BY 1-2C FROM SUBSIDENCE WARMING ALONG WITH A LGT SLY FLOW SHOULD ALLOW INLAND TEMPS TO REACH INTO THE UPR 70S TO AROUND 80. 00Z AND 12Z MODELS TRENDING SLIGHTLY SLOWER WITH NEXT SYSTEM DUE INTO WRN ZONES SUN EVENING THEN SPREADING EAST LATER SUN NIGHT. ONLY KEPT CHC OF TSRA IN WRN HALF ZONES ON SUNDAY AFT...THEN BROUGHT CHC POPS INTO ENTIRE CWA SUN NIGHT INTO MONDAY AS SYSTEM MOVES THROUGH. EXTENDED...(TUE THROUGH THU)...00Z OPERATIONAL MODELS AND GFS ENSEMBLE MEAN INDICATED 5H TROUGH AXIS LINGERING OVER THE AREA ON TUE STILL JUSTIFING IN LOW CHC POP FOR MAINLY DIURNAL SHRA. WED INTO THU...WX PICTURE BECOMES A BIT MORE UNCERTAIN IN A NW FLOW BETWEEN 5H TROUGH TO THE EAST AND WEST COAST RDG. 00Z OPERATIONAL GFS AND 12Z ECMWF SHOW ANOTHER POSSIBLE WEAK SHRTWV MOVING DOWN LATE WED ALTHOUGH NO ASSOC BOUNDARY REFLECTED AT THE SFC WITH THIS FEATURE. MEANWHILE...CANADIAN ENSEMBLE AND PROJECTED OPERATIONAL UKMET INDICATE MEAN UPR RDG BUILDING IN FM THE NRN PLAINS AT THIS TIME. GIVEN THE UNCERTAINTY AND THE FACT THAT MOISTURE RETURN WILL BE LIMITED AHEAD OF ANY NW FLOW SYSTEM...WILL ELECT TO KEEP THIS PD DRY FOR NOW. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VOSS mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 1120 AM CDT THU AUG 4 2004 .DISCUSSION...WILL ISSUE A QUICK UPDATE...MAINLY TO INCREASE POPS A BIT IN THE EAST/SE AND TO TWEAK THE DIURNAL TEMP CURVE. MAX TEMPS ARE PRETTY CLOSE AND HAVE NOT MADE ANY ADJUSTMENTS THERE. HAVE FIXED THE TEMP CURVE AS SOME LOCATIONS WILL SEE THEIR HIGH IN THE NEXT FEW HRS...OTHERS A BIT LATER. TOUGH TEMP CURVE TODAY WITH FROPA...CLDS AND RAIN. CURRENT TRENDS AND DATA FROM THE RUC40 INDICATE THIS BAND OF SHRA/TSRA WILL REGENERATE AND MOVE ACROSS THE E-CENTRAL AND SE CWA. DUE TO THE STRONG THETA E ADVECTION AT 850 MB AND COMBINATION OF THE 500 MB SHORT WAVE...FEEL THIS BAND OF ACTIVITY WILL CONSOLIDATE AND BRING MEASURABLE RAIN...OVERALL NOT TOO MUCH...TO A LARGE PART OF THE EASTERN CWA. THUS HAVE INCREASED POPS THERE TO 60%. ALSO FEEL THAT THERE COULD BE ADDITIONAL ACTIVITY DEVELOP ALONG THE FRONT...WHICH IS CURRENTLY IN N MS...LATER THIS AFTERNOON. THIS WOULD MAINLY BE ALONG AND SOUTH OF I-20 WHERE THE BEST LOW-LEVEL MOISTURE RESIDES. BASICALLY HAVE LEFT THE 40% POPS GOING FOR THE REST OF THE AREA. .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ 36/ENTREMONT ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 335 PM CDT THU AUG 5 2004 .DISCUSSION... CURRENT SURFACE ANALYSIS SHOWING A SURFACE RIDGE IN THE CENTRAL PLAINS. TEMPERATURES ARE 10 DEGREES BELOW NORMAL THIS AFTERNOON WITH CAA STILL OCCURING WEAKLY. WILL SEE ANOTHER COOL NIGHT TONIGHT. DEWPOINTS ARE STILL IN THE UPPER 50S...WITH LOWER 50S FOUND IN ILLINOIS. AIMING TO GET INTO THE LOW 50S DEWPOINTS HERE...AIDED BY LIGHT WINDS AND CLEAR SKIES OVERNIGHT. WILL SEE NEAR RECORD LOWS...WITH THE CLOSEST TO RECORD EXPECTED AT KSTJ. STILL COOLER AIR IN PLACE ON FRIDAY...BUT STARTING TO SEE SOME MIDLEVEL WARM UP BY THE END OF THE DAY. SHOULD SEE HIGH TEMPS A COUPLE DEGREES WARMER THAN TODAY. THE WARMING TREND CONTINUES INTO THE WEEKEND AS RETURN FLOW SETS BACK UP AGAIN. THE MAIN FEATURE OF INTEREST IN THE EXTENDED PORTION OF THE FORECAST IS THE PACIFIC NORTHWEST MID/UPPER LOW THAT IS PROGGED TO SKIRT THE CANADIAN/US BORDER AND THEN DIVE SOUTHEAST ACROSS THE NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY REGIONS AT THE END OF THE WEEKEND INTO EARLY NEXT WEEK. MEDIUM RANGE MODEL AGREEMENT IS FAIRLY GOOD WITH RESPECT TO THIS FEATURE. WILL MAINTAIN CHANCE POPS ON SUNDAY AND MONDAY ASSOCIATED WITH THE FRONTAL PASSAGE. THE MAIN INHIBITING FACTOR FOR WIDESPREAD THUNDERSTORMS MAY BE LIMITED MOISTURE WITHOUT ACCESS TO AN ADEQUATE FETCH OF GULF MOISTURE...SO WILL NOT INCREASE CURRENT 30-40 POPS. ON WEDNESDAY...THE ECMWF AND GFS MODELS PROG A SECOND SHORTWAVE TO FOLLOW ON THE HEELS OF THE AFOREMENTIONED WAVE...BUT WILL MAINTAIN POPS BELOW 20 PERCENT FOR NOW DUE TO TIMING/PLACEMENT/MOISTURE UNCERTAINTIES. AS FAR AS TEMPERATURES ARE CONCERNED...EXPECT BELOW-NORMAL READINGS THROUGH THE EXTENDED PERIOD. LVQ/LS && .PREV DISCUSSION... 300 AM THU... STRATUS HAS BEEN ERODING EARLY THIS MORNING AS DRIER AIR ADVECTS IN FROM THE NORTHEAST. MID LEVEL COLD ADVECTION HAS ALSO AIDED IN THE EROSION OF THE LOW CLOUD DECK BY EATING INTO THE INVERSION LAYER ABOVE THE STRATUS. THE RUC MODEL SIMULATED THE LOW LEVEL ATMOSPHERIC PROFILE THE BEST DURING THIS UNUSUAL EARLY AUGUST STRATUS EVENT. USING THE RUC FORECAST SOUNDINGS AND 925MB RELATIVE HUMIDITIES, THE LOW CLOUD DECK SHOULD BE ERODED IN ALL BUT THE PAOLA AND BUTLER AREAS BY SUNRISE. WITH THE EXCEPTION OF SOME CIRRUS BLOW OFF FROM STORMS ON THE HIGH PLAINS THE FORECAST AREA SHOULD ENJOY MOSTLY SUNNY SKIES TODAY. TEMPERATURES WILL DROP TO NEAR RECORD LEVELS TONIGHT. KANSAS CITY'S RECORD LOW IS 55 DEGREES (1990) AND SAINT JOSEPH'S IS 54 DEGREES (ALSO 1990). ONE MUST LOOK TO SOUTHERN MINNESOTA AND WISCONSIN TO FIND LOW TO MID 50S DEWPOINTS ON THIS MORNING'S SURFACE CHART. GETTING THIS DRY AIR INTO NORTHWEST MISSOURI, FOR OPTIMAL RADIATIONAL COOLING, MAY BE TOUGH WITH RELATIVELY MOIST SOIL CONDITIONS IN THE REGION. CIRRUS BLOW OFF FROM STORMS ON THE HIGH PLAINS TONIGHT MAY ALSO IMPEDE RADIATIONAL COOLING SOMEWHAT. SAINT JOSEPH WILL PROBABLY HAVE A BETTER SHOT TO BREAK THE RECORD TONIGHT SINCE THE ASOS SITS IN THE MISSOURI RIVER VALLEY. WINDS THERE WILL LIKELY DECOUPLE EARLY THIS EVENING. THE SENSOR AT MCI SITS CONSIDERABLY HIGHER IN ELEVATION AND WILL LIKELY ENDURE AN EAST WIND AROUND 5KTS ALL NIGHT LONG. COOL SURFACE HIGH PRESSURE WILL RESIDE OVER THE MIDWEST THROUGH THE EARLY PART OF THE WEEKEND. AN AREA OF LOW PRESSURE OFF THE COAST OF THE PACIFIC NORTHWEST WILL ULTIMATELY TRACK INTO THE NORTHERN PLAINS ON SUNDAY AND DISLODGE IT. GULF MOISTURE WILL BE SLOW TO RETURN TO THE CENTRAL AND SOUTHERN PLAINS ON SUNDAY NIGHT AND MONDAY AS THE COLD FRONT ASSOCIATED WITH THE AFOREMENTIONED UPPER LOW TRACKS INTO THE REGION. THE ECMWF AND GFS ARE SIMILAR WITH THE TIMING OF THESE FEATURES, BUT MOISTURE RETURN WILL DETERMINE WHETHER CONVECTION WILL BE ISOLATED OR WIDESPREAD WITH FRONTAL PASSAGE EARLY NEXT WEEK. FOR NOW WE HAVE ONLY 30 TO 40 PERCENT CHANCES FOR THUNDERSTORMS ON SUNDAY AND MONDAY. KOCH && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ WFOEAX mo