AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PHOENIX AZ 905 PM MST WED JUL 21 2004 SOUTHWEST AND SOUTH-CENTRAL ARIZONA...AND SOUTHEAST CALIFORNIA FORECAST DISCUSSION .SYNOPSIS... AN UPPER LEVEL HIGH PRESSURE CENTER CURRENTLY SITUATED OVER FAR SOUTHEAST ARIZONA WILL GRADUALLY SHIFT TO NORTHERN ARIZONA THE NEXT FEW DAYS. AS THIS OCCURS...ADDITIONAL MOISTURE WILL MOVE INTO THE SOUTHWEST AND SOUTH-CENTRAL DESERTS...AS WELL AS SOUTHEAST CALIFORNIA BY THE UPCOMING WEEKEND. THEREFORE...EXPECT AN INCREASE IN SHOWERS AND THUNDERSTORMS BY FRIDAY AND THEREAFTER. TEMPERATURES WILL REMAIN HOT THE NEXT COUPLE OF DAYS...BEFORE DROPPING OFF A FEW DEGREES BY FRIDAY AND SATURDAY. && .DISCUSSION... 00Z UPPER AIR DATA INDICATED THE CONTINUED STRONG ANTICYCLONIC FLOW OVER ARIZONA. 400 MB STREAMLINES SHOWED THE RIDGE AXIS HAD WOBBLED TO A NEARLY N-S ORIENTATION WITH THE CENTER JUST ABOUT OVER TUCSON. INCREASED WINDS ALOFT...FROM THE SW...CUT ACROSS MOST OF OUR CWA WITH A SLIGHTLY DIFFLUENT FLOW EVIDENT ACROSS PARTS OF NORTHERN GILA COUNTY...AND NE INTO THE 4 CORNERS. SOUNDINGS ALSO INDICATED SLIGHTLY DRIER AIR ACROSS THE PHOENIX AREA...PW DOWN TO 1.11 INCHES AND SURFACE DP'S RANGING FROM THE UPPER 40S TO THE LOWER 60S. OVERALL...ACROSS THE CWA...MOST SITES WERE DOWN SEVERAL DEGREES FROM 24HRS AGO...IN SPITE OF THE GULF SURGE THAT WAS OBSERVED EARLIER. MAX TEMPS WELL ABOVE 110 IN SOME AREAS...AND KPHX WAS ONLY 1 DEG SHY OF THE RECORD MAX FOR THE 21ST. RUC NOW INDICATES A FEW WEAK IMPULSES TRYING TO ROTATE AROUND THE SOUTHERN PERIMETER OF THE HIGH. EARLY EVENING CONVECTION ACROSS SE AZ WAS DISSIPATING QUICKLY...ALTHOUGH DEBRIS CLOUDS MAY BE LINGERING WELL INTO THE NIGHT SPCLY ACROSS EASTERN ZONES. NEXT COUPLE DAYS WILL BE HOT AGAIN AS THE UPPER HIGH IS ANCHORED OVER AZ. HOWEVER...BY FRIDAY NIGHT AND INTO SATURDAY...GFS POINTS AT A SUBSTANTIAL 700MB INCREASE IN DEW POINTS ALONG THE MEX-ARIZ BORDER THAT MOVES WESTWARD INTO SE CALIF BY SAT AFTERNOON. BULLSEYE OF 9C DEVELOPS OVER CALIF ZONE 33 BY SUNDAY AFTERNOON. FORECASTS HAVE THE INCREASED CHANCES OF PRECIP FOR THE UPCOMING WEEKEND...AND THAT LOOKS VERY GOOD AT THIS TIME. NO UPDATES. NOTE...IOP #3 FOR THE NAME PROJECT WILL RUN THROUGH 00Z FRI. .PSR WATCHES/WARNINGS/ADVISORIES... AZ...HEAT ADVISORY THU FOR SOUTH CENTRAL AZ ZONES 22...23...27...28. CA...NONE. && SAS az AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 930 PM EDT WED JUL 21 2004 .DISCUSSION...WATER VAPOR IMAGERY AND RUC UPPER STREAMLINES INDICATE DRIER AIR IN THE MID/UPPER LEVELS ACROSS THE NRN HALF OF THE PENINSULA COMPLIMENTS OF NW FLOW AS UPPER TROUGH SWINGS OFFSHORE FROM THE MID ATLC. KXMR EVENING SOUNDING SHOWS DRYING TO 700 MBS AND TO 800 MBS ON KTBW SOUNDING. EAST COAST BREEZE WORKED THROUGH LAKE COUNTY AND TO THE KISSIMEE RIVER WITH ONLY A FEW SHOWERS (<10 PCT COVERAGE) THIS EVENING. CONCERN FOR THE OVERNIGHT IS REDEVELOPMENT OF FOG/STRATUS. PERSISTENT HAZE LAYER STILL VISIBLE ON EARLY EVENING VSBL SATELLITE PICS. LGT WINDS...M CLR SKIES...MOIST LOW LYRS AND CLOUD CONDENSATION NUCLEI EXPECTED TO LEAD TO UNSEASONABLE FOG/STRATUS DEVELOPMENT AFTER MIDNIGHT. SFC TO H8 FLOW PROGD TO BECOME LIGHT NE/NNE WITH SFC FLOW BECOMING LIGHT TO CALM. WILL REMOVE EARLY EVENING SLGT CHC POP MENTION ACROSS THE FAR SRN AREAS AND CONTINUE WITH AREAS OF DENSE FOG DEVELOPING OVER THE NRN 2/3RDS OF THE FORECAST AREA. && .MARINE...GENERALLY LIGHT WINDS FROM THE NE EXPECTED...EXCEPT NW NEAR THE COAST WITH A LGT LAND BREEZE AFTER MIDNIGHT. SEAS AROUND 1 FT. && .MLB WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VOLKMER/SPRATT fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSONVILLE FL 900 PM EDT WED JUL 21 2004 WATER VAPOR SATELLITE IMAGERY AND RUC GUIDANCE SHOW DRY AIR CONTS OVER THE AREA WITH CWA BETWEEN AN UPPER TROUGH OFF THE ATLC E COAST AND UPPER HIGH OVER THE FL STRAITS. AT THE SFC...WEAK PRES PATTERN IN PLACE WITH LIGHT WINDS AND STILL HAZY WITH A FEW SPOTS CURRENTLY REPORTING 4-5SM IN HAZE OTHERWISE SKIES EXPECTED TO BE MOSTLY CLEAR TONIGHT. IR IMAGERY AND RADAR DATA SHOW E COAST SEA BREEZE HAS MOVED TO W OF INTERSTATE 75 S OF GNV AND E OF IT N OF GNV. ISOLD PIN HEAD SHOWERS DEVELOPED EARLIER BUT WERE VERY BRIEF DUE TO SUBSIDENCE AND PWATS OF ONLY 1.3 INCHES PER JAX 00Z SOUNDING. IT'S NOTED THAT ETA AND GFS PWATS ARE ABOUT 0.2 INCHES TOO HIGH AT 00Z COMPARED TO GOES AND RAOB SOUNDING. SUBSIDENCE AND LIGHT WINDS TONIGHT WILL PROMOTE PATCHY FOG AND IS ALREADY IN FORECAST. MIN TEMPS EARLY THIS MORNING DROPPED INTO THE MID 60S OVER THE NW ZONES (WITH A RECORD LOW OF 63 AT ALMA) AND EXPECT SIMILAR NUMBERS FOR TONIGHT GIVEN UNSEASONABLY LOW DEWPOINTS THIS AFTN WITH MIN DEWPOINT NEAR 60 IN PARTS OF NE FL AND SE GA. FOR THE UPDATE...WILL REMOVE EVENING PRECIP AND TWEAK GRIDS FOR SLIGHTLY LOWER TEMPS FOR SE GA. MARINE...CURRENT OBS SHOW WINDS ARE LESS THAN 10 KT AND SEAS AOB 2 FT. LITTLE TO NO CHANGE EXPECTED TONIGHT FOR THE UPDATE. .JAX WATCHES/WARNINGS/ADVISORIES... FL...NONE. GA...NONE. && $$ ARS fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 931 PM CDT WED JUL 21 2004 .DISCUSSION... WENT WITH FORECAST GENERALLY FOLLOWING RUC SOLUTION OF HIGHEST POPS AFTER 12Z WESTERN FORECAST AREA. CURRENT CONVECTION SLOW TO MOVE ALONG 850 BNDRY OVER SE SD/SRN MN. OVERNIGHT ENVIRONMENT QUITE JUICED WITH 16 DEG C TD POOLED ALONG TROF AXIS AT 850 OVER SRN 2/3 IA. WILL ADJUST OTHER GRID ELEMENTS TEMPS/TD/SKY/WIND. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ MR ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 307 PM CDT WED JUL 21 2004 .DISCUSSION... SHORT TERM FOCUS TONIGHT WL BE SECONDARY COLD FRONT MOVING THROUGH THE NORTHERN PLAINS AND THUNDERSTORM POTENTIAL ACROSS THE NORTH. NO SEVERE POTENTIAL ACROSS THE SE COUNTIES AND STORMS WILL EXIT CWA AROUND 4 PM. RUC HAS THE BEST HANDLE ON CURRENT CONVECTION ACROSS SOUTH DAKOTA AND TRANSLATES STORMS SOUTHWARD INTO NORTHERN IOWA TONIGHT. THE 18Z ETA IS ALSO MORE BULLISH WITH CONVERGENCE AND PRECIP OVER SRN MN. WL LEAN TOWARD WETTER SCENARIO AND CONTINUE POPS UNTIL 06Z NORTH...THEN SOUTHERN HALF THEREAFTER. WL UPDATE HWO TO MENTION ISOLD SVR POTENTIAL NORTH WITH DOWNBURST WIND THE MAIN THREAT. AS THE BOUNDARY CONTINUES TO MOVE SOUTH THROUGH IOWA...IT WILL STALL OUT ACROSS THE SOUTH AND PROVIDE THE FOCUS FOR ADDITIONAL THUNDERSTORM DEVELOPMENT FROM MIDDAY ON. HIGH INSTABILITY/WEAK SHEAR ENVIRONMENT TOMORROW WITH SOUNDINGS AGAIN SUGGESTING SOME DOWNBURST POTENTIAL. POPS CONTINUE THURSDAY NIGHT FAR SOUTH AS BOUNDARY PROGRESSES OUT OF THE STATE. FOLLOWED MET GUIDANCE GENERALLY FOR TEMPS OVER THE NEXT SEVERAL DAYS. SFC HIGH PUSHED DOWN FRIDAY TO PROVIDE UNSEASONABLY COOL AND COMFORTABLE TEMPS THROUGH THE WEEKEND. IN THE LONGER TERM (SUN-WED)...WL MAINTAIN POPS SUN AFT/EVE ACRS THE WESTERN COUNTIES AS MEDIUM RANGE MODELS CONTINUE TO SAG H5 TROUGH INTO THE REGION WITH SOME RIGHT REAR QUAD DYNAMICS. MOISTURE WL BE LIMITED WITH SFC HIGH IN PLACE...SO NOTHING MORE THAN SLT CHC WARRANTED ATTM. LOOKING AT A MAINLY DRY PATTERN THROUGH THE BALANCE OF THE FORECAST PERIOD. THE GFS BREAKS OFF A COMPACT S/W TO AFFECT THE CWA ON WEDNESDAY...WHILE THE ECMWF IS SUGGESTING KEEPING THE MAIN ENERGY TO THE NORTH. NOT ENOUGH CONFIDENCE TO INTRODUCE DAY 7 POPS ATTM. TEMPS WILL START OUT MUCH COOLER THAN NORMAL ON SUNDAY...WITH BUILDING HEIGHTS AND MORE HOT-HUMID AIR WORKING IN FROM THE WEST TOWARD THE END OF THE PERIOD. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ KINNEY ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 1055 AM MDT WED JUL 21 2004 .UPDATE...PERSISTENT MID/HIGH CLOUDS COMBINED WITH HIGH BASED SHOWERS/THUNDERSTORMS ALONG AND SOUTH OF WEAK FRONTAL BOUNDARY WILL LIMIT THE AMOUNT OF WARMING ACROSS THE SOUTHEAST ZONES. AN UPDATE WILL BE ISSUED SHORTLY TO LOWER HIGHS. POPS APPEAR ON TRACK WITH NO CHANGES PLANNED AT THIS TIME. MWM && .PREV DISCUSSION... 200 AM MDT WED JUL 21 2004 FORECAST CHALLENGES ARE QUITE A FEW FOR THE NEXT 3 DAYS AS THE COMBINATION OF A FRONTAL BOUNDARY AND FAVORABLE FLOW ALOFT INCREASE THE CHANCE OF PRECIPITATION FOR MUCH OF THE AREA. TEMPERATURES...ESPECIALLY FRIDAY WILL BE TRICKY AND SIGNIFICANTLY BELOW NORMAL FOR THIS TIME OF YEAR. AT 08Z ISOLATED THUNDERSTORMS HAVE POPPED UP OVER GRAHAM COUNTY... COINCIDENT WITH WEAKLY CAPPED ENVIRONMENT AS WELL AS THETA-E AXIS AND LOW LEVEL JET AXIS. ELSEWHERE...SURFACE TROUGH BISECTS THE CENTER OF THE FORECAST AREA FROM NORTHEAST TO SOUTHWEST. TODAY/TONIGHT...SUBTLE FRONTAL BOUNDARY/WIND SHIFT LINE SETS UP ALONG THE SOUTHEAST 1/3 OR SO OF OUR FORECAST AREA. AT THE SAME TIME...MID LEVEL MOISTURE AXIS ALIGNS ITSELF IN A SIMILAR FASHION AROUND THE SOUTHEAST STATES UPPER HIGH. GIVEN SOME RIGHT REAR UPPER JET ACTION ALONG WITH WEAKLY CAPPED ENVIRONMENT WILL SHOOT FOR CHANCE POPS OVER MUCH OF THE AREA BY LATE AFTERNOON. MID LEVEL LAPSE RATES NOT REALLY STEEP SO SEVERE STORMS NOT LIKELY. FOR TONIGHT PROBLEM IS LOCATION OF FRONTAL BOUNDARY. ETA HANGS IT UP ACROSS OUR AREA WHILE THE FSL RUC II AND NGM PUSH IT THROUGH. OTHER CONCERN IS PRECIP CHANCES. BEST INSTABILITY REMAINS OVER OUR NORTHERN AND NORTHWESTERN AREAS WHICH IS ALSO WHERE THE WIND SHIFT HANG UP AND BETTER MOISTURE COINCIDE. OTHER AREA IS FAR SOUTHERN/SOUTHEAST ZONES WHERE MOISTURE AVAILABILITY IS ALSO HIGHER AROUND THE SOUTHEAST STATES UPPER HIGH. TRENDS FROM THE MM5/FSL RUC II AND SURROUNDING NEIGHBORS FAVOR HIGH POPS ALONG AND NORTH OF THE INTERSTATE GIVEN ABOVE REASONING SO WILL TREND THAT WAY. HIGHS A BIT COOLER WITH READINGS IN THE LOW 90S WEST TO MID 90S EAST. THURSDAY/THURSDAY NIGHT...PRETTY DIFFICULT FORECAST REGARDING FRONTAL TIMING WITH SUBTLE DIFFERENCES BETWEEN THE ETA/GFS/NGM/FSL RUC II. BASIC SCENARIO SUGGESTS WIND SHIFT AROUND NOONTIME BUT USUALLY THE MODELS ARE A BIT SLOW. FOR NOW WILL TRY THE CONSENSUS ON BOTH TEMPERATURES AND WINDS. FOR TEMPERATURES...MOS GUIDANCE WOULD FAVOR MID/UPPER 80S WHILE 850 TEMPERATURES SUPPORT MID 80S TO LOWER 90S. GIVEN THE FRONTAL TIMING ISSUES AND PLENTIFUL CLOUDINESS/PRECIP WILL UNDERCUT THE MOS GUIDANCE CONSENSUS WITH READINGS CURRENTLY ADVERTISED. THUNDER CHANCES LOOK RATHER SLIM GIVEN THE COOLING AIRMASS AND STABLE LAPSE RATES. TOTAL TOTALS HOWEVER SUPPORT THUNDER WORDING SO WILL KEEP IT IN. GIVEN THE UPSLOPE FLOW I WOULD FAVOR HIGHEST QPF AMOUNTS OVER FAR EASTERN COLORADO. ETA/GFS BOTH BRING A DISTURBANCE OUT OF WYOMING THURSDAY NIGHT WITH INCREASING JET SUPPORT OVERTOP A NEARLY SATURATED ATMOSPHERE. GFS QPF A BIT MORE CONSISTENT THAN THE ETA BUT EITHER WAY YOU LOOK AT IT LIKELY POPS FOR RAIN WITH ISOLATED THUNDERSTORMS (JET SUPPORT) WARRANTED. FRIDAY/FRIDAY NIGHT...GIVEN THE HIGH BOUNDARY LAYER MOISTURE AS WELL AS REMAINDER OF THE ATMOSPHERE FRIDAY COULD BE RATHER RAW. 850 TEMPERATURES REVEAL HIGHS AT BEST 70 TO 75 WHICH MATCHES ALL THE 2M/MOS GUIDANCE NUMBERS EXCEPT THE GFS WHICH HAS 2M TEMPS AROUND 60 WEST TO NEAR 70 EAST. GFS SOLUTION MAY NOT BE TOO BAD AND WOULD BE RECORD LOW HIGH AT GLD (65 IN 1895). GIVEN THE TIME OF YEAR AND 109 YEAR RECORD WILL PUT READINGS RIGHT AROUND 70 OR SO. JET SUPPORT REMAINS OVERHEAD LEADING TO SOME LIGHT RAIN AND/OR DRIZZLE. RECORD LOW HIGH AT KGLD IS 65 OR SO BACK IN 1895 SO GOING 25 DEGREES OR SO UNDER CLIMATOLOGY IN JULY OF ALL THINGS IS SOMEWHAT IMPRESSIVE. WILL KEEP SOME LIGHT SHOWERS/DRIZZLE IN FOR FRIDAY NIGHT AS OVERCAST CONDITIONS CONTINUE. SATURDAY-TUESDAY...UPPER HIGH DOESNT REBUILD OVER THE WEST LIKE EARLIER THOUGHT. 850 TEMPERATURES CONTINUE TO SUPPORT COOLER THAN NORMAL READINGS AND ALTHOUGH CURRENT FORECAST IS BELOW LATEST MEX GUIDANCE IT MAY STILL BE TOO WARM. WILL LEAVE ALONE FOR NOW SINCE GRIDS FROM SURROUNDING PARTNERS MATCH BUT WILL LIKELY NEED TO BE TWEAKED AS WE GO. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ DDT ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1125 PM EDT WED JUL 21 2004 .UPDATE... WILL UPDATE FOR THE MIDNIGHT WORDING IN THE ZONES. WITH THE SHORTWAVE MOVING THROUGH SE LOWER BETWEEN 06Z AND 10Z...AND CURRENT RADAR TRENDS...WILL RAISE OVERNIGHT POPS ACROSS FAR SOUTHEAST LOWER MI. 00Z ETA CERTAINLY AGREES WITH THIS TOO. WILL GO WITH MAINLY RAIN SHOWERS WITH JUST A CHANCE OF THUNDERSTORMS GIVEN THE STABILIZATION THIS EVENING. RBP && .PREVIOUS DISCUSSION... GOOD SURFACE DEW POINT POOLING ACROSS FAR NORTHERN CWA NEAR WARM FRONT BOUNDARY WITH CAPES ALREADY IN EXCESS OF 3000J/KG. CONVECTION INITIALLY PULSING IN NATURE...WHICH IS A REFLECTION OF LACK OF DYNAMICS AND WARMING 700 MB TEMPERATURES. DEGREE OF INSTABILITY AND PWAT VALUES STILL CONCERNING THOUGH. MAIN MCS OVER SOUTHERN WISCONSIN ALSO STRUGGLING A LITTLE WITH SUBSTANTIAL CLOUD TOP WARMING THROUGH THE MORNING. MCS IS ALSO TURNING A LITTLE MORE SOUTHEAST AS SUGGESTED BY THE FORWARD PROP CORFIDI VECTORS. THIS MAY PLACE MAIN OUTFLOW BOUNDARY ACROSS THE NORTHERN OHIO VALLEY...RATHER THAN TRACKING EAST ACROSS LOWER MICHIGAN. HOWEVER MCV WORKING ACROSS LAKE MICHIGAN MAY BE STRONG ENOUGH TO PRODUCE SOME ORGANIZATION TO CONVECTION ACROSS THE NORTHERN PORTION OF CWA. MCV TRACKING EAST ACROSS IOWA WILL ALSO ORGANIZE POTENTIAL SEVERE CONVECTION THIS EVENING...WITH 03Z-09Z WINDOW. 10KM TAQ RUC HAS A GOOD HANDLE ON CONVECTION CURRENTLY FIRING OVER THE SAGINAW VALLEY AND TIP OF THUMB...WITH NO REAL ORGANIZATION THROUGH THE AFTERNOON HOURS...THEN BAND OF CONVECTION MOVING THROUGH CWA BETWEEN 03-09Z. GFS/ETA IN GOOD AGREEMENT THROUGH 84 HOURS OVER THE GREAT LAKES...WITH FROPA ACROSS THE NORTH HALF OF CWA BY NOON THURSDAY...THEN SWEEPING SOUTH INTO OHIO VALLEY BY 20Z. FIRST CONCERN THOUGH WILL BE CONVECTION AND HEAVY RAIN OVERNIGHT. BLUE RIVER PROFILER ALREADY SHOWING 45KT 850 MB WINDS...AND TAKING AIM ON SOUTHEAST LOWER THIS EVENING...PWAT INCREASING TO AROUND 2 INCHES...PRE FRONTAL TROF AND MCV BOTH WORKING ACROSS SOUTHERN LOWER BETWEEN 03-09Z. WILL ALSO SEE A GOOD INCREASE IN 0-3KM SHEAR VECTOR AS MID LEVEL WINDS INCREASE. MAIN THREAT WILL BE DAMAGING WINDS...HAIL SHOULD NOT BE MUCH OF A THREAT WITH WET BULB ZERO INCREASING TO GREATER THAN 13K. ONLY THING LACKING WILL BE UPPER JET SUPPORT...WHICH WILL HOLD OFF UNTIL THURSDAY AFTERNOON. WILL CONTINUE WITH CHC POPS THURSDAY AFTERNOON...ESPECIALLY SOUTH. GOOD COLD ADVECTION TO HOLD OFF UNTIL MID AFTERNOON AND RIGHT REAR QUAD OF 300 MB JET SETTING UP OVER SOUTHERN CWA AFTER 18Z. NEGATIVE 850 MB THETA-E ADVECTION BY 18Z SHOULD CUT OF ANY HOPE OF CONVECTION ACROSS THE NORTHERN CWA...THUS WILL MENTION A SLIGHT CHANCE..20 POP...ACROSS THE NORTHERN CWA THROUGH 18Z...THEN 40 POPS SOUTH. MODELS CONSISTENT WITH IMPRESSIVE COLD ADVECTION FOR LATE JULY FOR THURSDAY NIGHT INTO FRIDAY...WITH 850 MB TEMPS DROPPING TO +7C BY FRIDAY AFTERNOON. GUIDANCE TEMPERATURES LOOK TO WARM FOR THURSDAY AFTERNOON AND FRIDAY MORNING...WILL CUT BACK ABOUT 5 DEGREES. && .DTX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ GSS 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 1025 PM EDT WED JUL 21 2004 .DISCUSSION... POTENTIAL FOR CONVECTION AND SEVERE WX REMAIN THE MAIN FCST CONCERNS FOR TONIGHT. WV IMAGERY SHOWS A COUPLE MAIN SHORTWAVES. THE FIRST WHICH BROUGHT SOME TS EARLIER TODAY HAS MOVED INTO THE CENTRAL GREAT LAKES. THE OTHER IS PUSHING INTO NWRN ONTARIO. AT THE SFC...INITIAL FRONT HAS MOVED INTO THE CENTRAL U P...WITH A SECONDARY BOUNDARY IN THE FAR WESTERN U P. DRIER AIR IS ADVECTING INTO THE AREA BEHIND THIS SECOND BOUNDARY...AS DEWPTS FROM IWD TO CMX HAVE FALLEN INTO THE MID 60S... BUT REMAIN AROUND 70F IN CENTRAL AND EASTERN PARTS. REGARDING CONVECTION...STILL NOTHING TO SPEAK OF ACROSS THE CWA AS OF 02Z. TS IN NRN WI HAS DIMINISHED WITH LOSS OF SOLAR HEATING. BAND OF SHRA/TS IN CENTRAL MN IS PUSHING TO THE SE. RUC H3 DIVERGENCE SHOWS THE U P BEING UNDER UPPER CONVERGENCE...AND BELIEVE REGION OF SUBSIDENCE BETWEEN SHORTWAVES ALONG WITH A SOLID MID LEVEL CAP ARE THE REASONS FOR A LACK OF ACTIVITY THIS EVENING...DESPITE MLCAPES ON ORDER OF 2K-3K J/KG AND A FROPA. IN FACT...00Z GRB RAOB SHOWS A VERY WARM LAYER NEAR 800MB (17C) WHICH WAS SORELY UNDERDONE BY THE ETA. SHRA/TS IN MN LINES UP REASONABLY WELL WITH A BAND OF H8 THETA-E ADVECTION AND REGION OF H3 DIVERGENCE IN RRQ OF 90KT JET MOVING IN ONTARIO. THE DIVERGENCE ALOFT DOES SPREAD INTO THE WESTERN U P BY 03Z...PER THE RUC AND ETA...BUT THE THETA-E ADVECTION TRACKS TO OUR S. THIS SEEMS ACCURATE GIVEN KMQT VAD WINDS SHOW NWLY FLOW NOW AT 850MB...WHICH CONCURS WITH RUC'S VEERING H8 FLOW AND LATEST RADAR TRENDS. SO...ITS LOOKING LESS AND LESS FAVORABLE FOR CONVECTION IN THE U P. WILL THUS SLASH POPS TO ISOLD FOR THE REMAINDER OF THE NIGHT...WITH THE THINKING THAT WITH SOME UPPER SUPPORT AND AN UPSTREAM SFC BOUNDARY YET TO MOVE THROUGH...MAY STILL SEE SOMETHING DEVELOP. DO NOT BELIEVE ANYTHING WILL BECOME SEVERE AT THIS POINT...SO WILL UPDATE ZONES TO REFLECT THIS AS WELL. HAVE ALREADY UPDATED GRIDS TO ACCOUNT FOR WX CHANGES. WILL SEND UPDATED ZONES SHORTLY. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ JKL mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 423 PM EDT WED JUL 21 2004 ...MAIN FORECAST PROBLEMS POTENTIAL FOR SEVERE WEATHER TONIGHT... .DISCUSSION... ISENTROPIC LIFT INITIATED EARLIER CONVECTIVE ACTIVITY ACROSS UPPER MICHIGAN WHICH HAS NOW MOVED INTO THE FAR ERN U.P. THIS AFTERNOON. SFC BOUNDARY EXTENDING FROM LOW OVER NW ONTARIO INTO THE CENTRAL PLAINS THIS AFTERNOON CONTINUES TO GRADUALLY MOVE SE...WITH DEWPOINTS AS HIGH AS THE LOWER 70S OVER NRN WI. LATEST RUC SHOWS LI/S DROPPING TO AS LOW AS -8 AND CAPES CLIMBING IN EXCESS OF 3000 J/KG OVER THE WRN U.P. LATE THIS AFTERNOON AS DECENT MOISTURE POOLING CONTINUES AHEAD OF THE BOUNDARY. LATEST SATELLITE IMAGERY SHOWS CU FILED OVER MN ARROWHEAD INTO NE WI THIS AFTERNOON...WITH THUNDERSTORMS FIRING OVER THE ERN DAKOTAS. BUFKIT SHOWED CAPPING IN PLACE OVER THE U.P. WEAKENS WITH THE APPROACH OF THE BOUNDARY. THIS AGREES WITH RUC AS IT SHOWS CIN WEAKENING IN THOSE AREAS. AS THIS BOUNDARY MOVES IN LATE THIS AFTERNOON...EXPECT THUNDERSTORMS TO DEVELOP AND SPREAD EASTWARD ACROSS UPPER MICHIGAN. THERE IS A POTENTIAL FOR SEVERE STORMS AS ATMOSPHERE QUITE UNSTABLE...HOWEVER 3KM HELICITY VALUES GENERALLY STAY AT OR BELOW 150. WET BULB ZEROES FALLING TO AROUND 10K FT WHILE 850 TO 500 MB FLOW BECOMES MORE UNIDIRECTIONAL WITH TIME. EARLIER FORECASTS HAD MENTION OF POTENTIAL SEVERE THUNDERSTORMS THROUGH THE EVENING WITH LARGE HAIL AND DAMAGING WINDS THE PRIMARY THREATS...AND WILL KEEP THIS GOING. AS FIRST BOUNDARY SWINGS THROUGH THE REGION OVERNIGHT... PRECIPITATION TO END FROM W TO E WITH SOME LINGERING SHOWERS AND THUNDERSTORMS OVER THE FAR E. WITH SHEARED VORT MAX MOVING THROUGH EARLY IN THE DAY ON THU...HAVE KEPT IN A MENTION OF SHOWERS OVER THE NRN LAKE ALTHOUGH DECENT 850 TO 500 MB Q VECTOR CONVERGENCE MOVING IN BY AFTERNOON. COLD FRONT THEN DROPS INTO THE REGION ON THU...WITH 850 MB TEMPS FALLING OFF SIGNIFICANTLY DURING THE DAY AS 5H LOW MOVES INTO HUDSON BAY. MODEL TRENDS HAVE BEEN BACKING OFF ON THE AMOUNT OF COOLING THE PAST FEW RUNS...SO WILL KEEP TEMPS SLIGHTLY ABOVE MOS GUIDANCE. HIGH PRESS SETTLES INTO THE REGION THU NIGHT THROUGH FRI...AND REMAINS ANCHORED OVER THE GREAT LAKES REGION THROUGH THE WEEKEND. GFS HAS BEEN DEPICTING THE DEVELOPMENT OF A SHORT WAVE OVER THE PLAINS SUN...AND LIFTS THIS FEATURE INTO THE U.P. EARLY IN THE WORK WEEK. WITH SFC RIDGE AXIS STILL IN PLACE...SEE NO REASON TO PLACE MENTION OF PCPN IN THE EXTENDED. TEMPS TO GENERALLY STAY ON THE COOL SIDE FROM THU ON INTO SAT...WITH A RECOVER TO CLOSER TO NORMAL READINGS THROUGH THE REMAINDER OF THE EXTENDED. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ RJT mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 130 PM EDT WED JUL 21 2004 .DISCUSSION... GOOD SURFACE DEW POINT POOLING ACROSS FAR NORTHERN CWA NEAR WARM FRONT BOUNDARY WITH CAPES ALREADY IN EXCESS OF 3000J/KG. CONVECTION INITIALLY PULSING IN NATURE...WHICH IS A REFLECTION OF LACK OF DYNAMICS AND WARMING 700 MB TEMPERATURES. DEGREE OF INSTABILITY AND PWAT VALUES STILL CONCERNING THOUGH. MAIN MCS OVER SOUTHERN WISCONSIN ALSO STRUGGLING A LITTLE WITH SUBSTANTIAL CLOUD TOP WARMING THROUGH THE MORNING. MCS IS ALSO TURNING A LITTLE MORE SOUTHEAST AS SUGGESTED BY THE FORWARD PROP CORFIDI VECTORS. THIS MAY PLACE MAIN OUTFLOW BOUNDARY ACROSS THE NORTHERN OHIO VALLEY...RATHER THAN TRACKING EAST ACROSS LOWER MICHIGAN. HOWEVER MCV WORKING ACROSS LAKE MICHIGAN MAY BE STRONG ENOUGH TO PRODUCE SOME ORGANIZATION TO CONVECTION ACROSS THE NORTHERN PORTION OF CWA. MCV TRACKING EAST ACROSS IOWA WILL ALSO ORGANIZE POTENTIAL SEVERE CONVECTION THIS EVENING...WITH 03Z-09Z WINDOW. 10KM TAQ RUC HAS A GOOD HANDLE ON CONVECTION CURRENTLY FIRING OVER THE SAGINAW VALLEY AND TIP OF THUMB...WITH NO REAL ORGANIZATION THROUGH THE AFTERNOON HOURS...THEN BAND OF CONVECTION MOVING THROUGH CWA BETWEEN 03-09Z. GFS/ETA IN GOOD AGREEMENT THROUGH 84 HOURS OVER THE GREAT LAKES...WITH FROPA ACROSS THE NORTH HALF OF CWA BY NOON THURSDAY...THEN SWEEPING SOUTH INTO OHIO VALLEY BY 20Z. FIRST CONCERN THOUGH WILL BE CONVECTION AND HEAVY RAIN OVERNIGHT. BLUE RIVER PROFILER ALREADY SHOWING 45KT 850 MB WINDS...AND TAKING AIM ON SOUTHEAST LOWER THIS EVENING...PWAT INCREASING TO AROUND 2 INCHES...PRE FRONTAL TROF AND MCV BOTH WORKING ACROSS SOUTHERN LOWER BETWEEN 03-09Z. WILL ALSO SEE A GOOD INCREASE IN 0-3KM SHEAR VECTOR AS MID LEVEL WINDS INCREASE. MAIN THREAT WILL BE DAMAGING WINDS...HAIL SHOULD NOT BE MUCH OF A THREAT WITH WET BULB ZERO INCREASING TO GREATER THAN 13K. ONLY THING LACKING WILL BE UPPER JET SUPPORT...WHICH WILL HOLD OFF UNTIL THURSDAY AFTERNOON. WILL CONTINUE WITH CHC POPS THURSDAY AFTERNOON...ESPECIALLY SOUTH. GOOD COLD ADVECTION TO HOLD OFF UNTIL MID AFTERNOON AND RIGHT REAR QUAD OF 300 MB JET SETTING UP OVER SOUTHERN CWA AFTER 18Z. NEGATIVE 850 MB THETA-E ADVECTION BY 18Z SHOULD CUT OF ANY HOPE OF CONVECTION ACROSS THE NORTHERN CWA...THUS WILL MENTION A SLIGHT CHANCE..20 POP...ACROSS THE NORTHERN CWA THROUGH 18Z...THEN 40 POPS SOUTH. MODELS CONSISTENT WITH IMPRESSIVE COLD ADVECTION FOR LATE JULY FOR THURSDAY NIGHT INTO FRIDAY...WITH 850 MB TEMPS DROPPING TO +7C BY FRIDAY AFTERNOON. GUIDANCE TEMPERATURES LOOK TO WARM FOR THURSDAY AFTERNOON AND FRIDAY MORNING...WILL CUT BACK ABOUT 5 DEGREES. && .DTX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ GSS EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 315 PM CDT WED JUL 21 2004 .DISCUSSION... CLUSTER OF THUNDERSTORMS ACROSS SOUTHEASTERN ND APPEARS TO BE ASSOCIATED WITH ZONE OF LOW LEVEL CONVERGENCE. NOT REALLY CONFIDENT OF LATEST RUC SOLUTION...BUT CAN VISUALIZE THE CLUSTER EXPANDING SOUTHEAST ON INFLOW SIDE OF COMPLEX AS CIN WEAKENS RAPIDLY THIS AFTERNOON. OVER REST OF CWA HAVE GONE WITH ISOLATED THUNDERSTORMS THIS EVENING AS LOW CIN HIGH SFC BASED CAPE ENVIRONMENT CONDUCIVE FOR CONVECTION...BUT LACK OF DECENT BOUNDARIES SUGGEST LACK OF ORGANIZED CONVECTION...AND THE CONVECTION MAY BE VERY DIURNAL IN NATURE. AFTER "TONIGHT" FORECAST SIMPLIFIES AS BOTH 12Z ETA AND 12Z GFS SIMILAR IN USHERING IN COOLER DRIER AIR WHICH LAST THROUGH THE BULK OF THE "SHORT TERM" (THROUGH SATURDAY). NO MAJOR CHANGES FROM PREVIOUS GRIDS IN THE THURSDAY THROUGH SATURDAY. LONGER TERM...SUNDAY THROUGH WEDNESDAY ENSEMBLE 850 MB TEMP ANOMS STILL SUGGEST SLIGHTLY COOLER THAN NORMAL TEMPS INTO MONDAY..THEN SURFACE RIDGE STARTS TO SLIP EAST. 12Z UKMET CONSISTENT WITH 00Z GFS FORMING AN UPPER LOW OVER THE HIGH PLAINS AND MIGRATING IT EAST TOWARD MN BY TUESDAY. ENSEMBLE PRECIP PROBS INCREASE A BIT BY WED OVER AREA BUT WILL HOLD OFF FOR NOW AND WAIT FOR LATER RUNS. && MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ RJN/JPR mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 800 PM CDT WED JUL 21 2004 .DISCUSSION...WITH THE RIDGE OF HIGH PRESSURE FIRMLY ENTRENCHED OVER THE AREA THIS EVENING...EXPECT MORE OF THE SAME. FOG FORMATION SHOULD BEGIN IN SOME AREAS BY 10 PM AS THE EVENING TEMPERATURES FALL TO BE NEAR THE DEW POINTS. IF LATEST RUC RUN IS RIGHT...EXPECT THE SOUTHERN AREAS TO SEE THE FOG FORMATION FIRST. AT ANY RATE...GIVEN LESS BL MOISTURE THAN ON PREVIOUS NIGHT...EXPECT THE FOG NOT TO BE PARTICULARLY DENSE. THE GFS DOES HINT AT SOME ISOLATED SHOWERS AND STORMS ON THURSDAY AFTERNOON AND AGAIN ON FRIDAY AFTERNOON. HOWEVER...GIVEN A DEVELOPING NORTHERLY FLOW AT 850 AND 700 MB...AND A STRONG RIDGE OVERHEAD...DISAGREE WITH THE GFS. INSTEAD THINK THAT THE SEA BREEZE FRONT WILL ONLY MAKE IT AS FAR NORTH AS HIGHWAY 84...THUS LEAVING MOST OF THE FORECAST AREA DRY. PLANNING ON NO UPDATES TO THE ZONES TONIGHT. EVERYTHING IS RIGHT ON TRACK IN THE SHORT TERM. & .PRELIMINARY POINT TEMPS/POPS... JACKSON 69 93 71 94 / 0 0 0 20 MERIDIAN 68 93 69 94 / 0 0 0 20 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ 18/HENRY ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 321 PM CDT WED JUL 21 2004 .DISCUSSION... THE ELEVATED CONVECTION THAT DEVELOPED EARLY IN THE DAY HAS LAID OUT AN WEST TO EAST SURFACE BOUNDARY OVER NORTHERN KANSAS. WITH SOUTHERLY WINDS AT 850MB OVER KANSAS AND OKLAHOMA, THUNDERSTORMS HAVE CONTINUED TO REGENERATE ALONG THIS FRONT ALL DAY. THE MODELS HAVE NOT BEEN ABLE TO INITIALIZE THIS MESOSCALE BOUNDARY SO THEY HAVE BEEN OF LITTLE USE FOR THE SHORT TERM FORECAST. I WOULD EXPECT THAT THIS BOUNDARY WILL CONTINUE TO BE THE MAIN FOCUS FOR CONVECTIVE ACTIVITY THROUGH THE EVENING AS THE LOW LEVEL JET BACKS AS IT TYPICALLY DOES AS THE HIGH TERRAIN OF THE ROCKIES COOLS. THIS SHOULD FOCUS CONVECTION FURTHER WEST LATE THIS EVENING. IF THIS SCENARIO PANS OUT, WEAK MID LEVEL WESTERLIES WILL PUSH SCATTERED SHOWERS AND THUNDERSTORMS INTO EASTERN KANSAS AND NORTHWEST MISSOURI DURING THE EARLY MORNING HOURS. CLOUDS BUSTED TEMPERATURES TODAY AND WILL BE A CONCERN AGAIN TOMORROW. I'VE LOWERED TEMPERATURES SEVERAL DEGREES BELOW GUIDANCE FOR THE WESTERN HALF OF THE FORECAST AREA EXPECTING CONVECTIVE DEBRIS FROM KANSAS TO HINDER OUR WARM UP TOMORROW. BY LATE IN THE DAY UNSEASONABLY STRONG COLD ADVECTION WILL SURGE INTO SOUTHERN NEBRASKA AND NORTHWEST MISSOURI. THE STRONG SYNOPTICALLY FORCED FRONT PROGGED BY THE ETA AND GFS LOOKS LIKE AN EARLY SPRING COLD FRONT. DEEP LAYER FRONTOGENESIS SHOULD PROVIDE EASTERN KANSAS AND NORTHERN MISSOURI WITH GOOD PRECIPITATION COVERAGE AS THE FRONT PLOWS INTO OUR TROPICAL AIRMASS. I HAVE RAISED PRECIPITATION CHANCES TO 60 TO 70 PERCENT IN MOST AREAS TOMORROW NIGHT. I HAVE LOWERED TEMPERATURES FOR FRIDAY, BUT THE NIGHT SHIFT MAY NEED TO DROP THEM FURTHER. POST FRONTAL RAIN SHOWERS, THICK CLOUD COVER, AND A NORTHEAST WIND MAY KEEP TEMPERATURES FROM REBOUNDING MUCH FRIDAY. I'VE DROPPED TEMPERATURES INTO THE MID 70S, BUT THAT MAY NOT BE ENOUGH. RECORDS MAY EVEN BE THREATENED BY THIS WEEKEND. SATURDAY'S RECORD LOW TEMPERATURE OF 59 DEGREES SET LAST YEAR MAY BE WITHIN REACH. KOCH NOT MUCH CHANGE SINCE YESTERDAY AS GFS CONTINUES PREVIOUS TREND TO CLOSE OFF A MID LEVEL LOW OVER THE CENTRAL U.S ON SUNDAY...IN THE GENERAL AREA OF EASTERN NEBRASKA AND IOWA. ECMWF TENDS TO LEAN TOWARDS THIS SOLUTION ALTHOUGH IT IS MORE PROGRESSIVE WITH THE FEATURE BY LATE MONDAY...WHILE THE 00Z CANADIAN SHOWS MORE OF A DEEP TROUGH WHICH IS ALSO PROGRESSIVE. DESPITE ALL THIS MOISTURE WILL LIKELY BE LACKING FOR ANY SIGNIFICANT PRECIPITATION AS THE SURFACE COLD FRONT WILL BE WELL TO THE SOUTH AND THUS INHIBITS NORTHWARD TRANSPORT OF DEEP MOISTURE. THERE COULD BE SOME RESIDUAL MOISTURE IN THE VICINITY OF THE CLOSED CIRCULATION IF IT FORMS BUT ANY RAIN SHOULD BE QUITE SCATTERED AND NOT WORTH PUTTING INTO THE FORECAST SO WILL LEAVE GOING FORECAST DRY. AS ALLUDED TO YESTERDAY ONE OF THE MORE NOTABLE WEATHER CONCERNS WILL BE THE UNSEASONABLY COOL TEMPERATURES...IN FACT RECORD BREAKING TEMPERATURES ARE POSSIBLE OVER THE WEEKEND AS MCI RECORD LOWS ARE IN THE MID TO UPPER 50S. AS SURFACE HIGH EVENTUALLY RETREATS TO THE EAST AND RETURN FLOW SETS UP WE SHOULD SEE A GRADUAL WARMUP BY MID WEEK. SO NEAR NORMAL TEMPERATURES PLUGGED INTO FORECAST. TILL THEN ENJOY THE COOL WEATHER. MJ && .PREVIOUS DISCUSSION... 1225 PM... TEMPERATURES ARE SLOWLY CLIMBING SOUTH OF THE MISSOURI RIVER, BUT THICK CIRRUS HAS PREVENTED THE WARM UP NEEDED TO REACH HEAT ADVISORY CRITERIA. TEMPERATURES WILL LIKELY TOP OUT IN THE LOWER 90S IN SEDALIA, WARRENSBURG, CLINTON AND HARRISONVILLE. THAT SHOULD PUT HEAT INDICES AROUND 100 DEGREES FOR AN HOUR OR TWO, WHICH IS WELL SHORT OF CRITERIA (100 DEGREES FOR AT LEAST 3 CONSECUTIVE HOURS). I'LL BE CANCELING THE HEAT ADVISORY SHORTLY. TEMPERATURES WILL BE ADJUSTED DOWN FROM SAINT JOSEPH TO KIRKSVILLE AS WELL. THE LEE SIDE TROUGH AT 850 MB WILL BE A STEADY STATE FEATURE THROUGH THE LATE AFTERNOON KEEPING THE BAND OF SHOWERS AND THUNDERSTORMS OVER NORTHERN KANSAS ONGOING TODAY. KOCH && 925 AM... RAIN SHOWERS AND THICK CLOUD COVER WILL LIKELY BRING AN EARLY END TO THE HEAT ADVISORY OVER PARTS OF NORTHEAST KANSAS AND NORTHERN MISSOURI. A LONG LOOP OF THE INFRARED SATELLITE OVERLAYED WITH RUC 700 MB TEMPERATURES INDICATES THAT SHOWERS AND THUNDERSTORMS IGNITED ALONG THE EDGE OF THE CAP IN NORTHEAST KANSAS AROUND SUNRISE. THE AXIS OF THE LOW LEVEL JET, BLOWING ABOUT 30 KTS, PROVIDED A GENERALLY FAVORABLE ENVIRONMENT FOR ASCENT, AND IT APPEARS THAT A GRAVITY WAVE OR OUTFLOW BOUNDARY FROM CONVECTION IN NEBRASKA CONTRIBUTED THE MESOSCALE LIFT TO ACTIVATE THE LINE OF STORMS. THE LOW LEVEL JET MAY BE WEAKENING ACCORDING TO 850 MB PROFILER DATA, BUT THE RUC SUGGESTS THAT ITS AXIS WILL LINGER OVER CENTRAL AND EASTERN KANSAS FOR MOST OF THE DAY. I EXPECT AN OVERALL WEAKENING OF CONVECTION, BUT THE DEBRIS WILL LINGER THROUGH AT LEAST THIS MORNING. THE HEAT ADVISORY POSTED OVERNIGHT WAS MARGINAL SO WITHOUT SUNSHINE THIS MORNING, IT WILL BE VERY TOUGH FOR AREAS NORTH OF THE RIVER TO REACH A 105 DEGREE HEAT INDEX FOR THREE HOURS THIS AFTERNOON. I WILL PROBABLY DROP THE ADVISORY FOR A GOOD CHUNK OF THE NORTHERN ZONES AFTER THE 10 AM OBSERVATIONS COME IN. KOCH && 200 AM... HEAT INDICES THE MAIN CONCERN TODAY WITH THE THREAT OF CONVECTION ENTERING THE PICTURE AGAIN LATE TONIGHT THROUGH FRIDAY. EVENING UPPER AIR INDICATED AN UPPER RIDGE ACROSS MUCH OF THE CENTRAL PLAINS WITH A RELATIVELY STRONG CAP FROM KANSAS EAST INTO MISSOURI. CONVECTION CONTINUES AROUND THE PERIPHERY OF THE RIDGE AND ALONG A SURFACE TROUGH LOCATED ACROSS NORTHERN KANSAS. CONVECTION MAINLY MOVING EAST WITH SLOW DEVELOPMENT SOUTH AS AN OUTFLOW BOUNDARY DRIFTS SOUTH. OVERALL...PREFER THE MESOETA SOLUTION THE NEXT COUPLE OF DAYS AS THE MESOETA NOT SUFFERING FROM CONVECTIVE FEEDBACK AS BAD WHEN COMPARED TO THE GFS. MESOETA APPEARS REASONABLE IN DRIFTING THE WEAK SURFACE TROUGH IN NEBRASKA SLOWLY SE INTO SE NEBRASKA THIS AFTERNOON...AS A WEAK UPPER TROUGH PROGRESSES EAST THROUGH THE NORTHERN PLAINS. AHEAD OF THE SURFACE TROUGH...INCREASING SOUTHWEST WINDS WILL INCREASE TEMPERATURES A LITTLE TODAY...AND WITH HIGH DEWPOINTS...MOST OF THE CWA WILL LIKELY REACH OR EXCEED HEAT ADVISORY CRITERIA. THE CAP WEAKENS SLIGHTLY THIS AFTERNOON WITH THE APPROACH OF THE SURFACE TROUGH. ALTHOUGH SHEAR RATHER WEAK...SUFFICIENT INSTABILITY PRESENT FOR A CHANCE OF THUNDERSTORMS LATE THIS AFTERNOON IN EXTREME NORTHWEST MO. SURFACE TROUGH TO ONLY INCH SOUTHEAST THROUGH THE NIGHT...HOWEVER AS THE UPPER FLOW AMPLIFIES ACROSS THE CONUS...A RATHER STRONG AND UNSEASONABLY COOL SURFACE HIGH WILL DRIVE A COLD FRONT INTO NORTHERN MISSOURI ON THURSDAY. AS THE CAP CONTINUES TO WEAKEN...MODERATE TO HIGH INSTABILITY ALONG THE FRONT ALONG WITH HIGH PRECIPITABLE WATER VALUES...WILL LEAD TO A GOOD CHANCE OF THUNDERSTORMS...MAINLY ACROSS THE NORTHERN ONE HALF OF THE CWA DURING THE DAY ON THURSDAY. THE SURFACE FRONT WILL CLEAR THE CWA THURSDAY NIGHT...HOWEVER THE H8 FRONT WILL BECOME NEARLY STATIONARY ACROSS NORTHERN MISSOURI. PINNING DOWN THE EXACT PLACEMENT OF THE SURFACE AND H8 FRONT IS DIFFICULT AND HEAVILY DEPENDENT UPON PREVIOUS CONVECTION AND ANY WEAK SHORTWAVES EMBEDDED IN THE FLOW. AS PER THE MESOETA...WEAK ISENTROPIC LIFT WILL DEVELOP ACROSS THE NRN HALF OF THE CWA THURSDAY NIGHT IN A VERY MOIST SURFACE TO H5 ENVIRONMENT. ALTHOUGH CONFIDENCE IS NOT HIGH...THERE APPEARS TO BE A GOOD THREAT OF RAIN AND CONVECTION WITH PRECIPITABLE WATER VALUES FROM 1.5-2 INCHES AND A FRONT IN THE AREA. THERE WILL ALSO BE A THREAT OF A FEW SEVERE THUNDERSTORMS MAINLY DURING THE AFTERNOON AND EVENING HOURS ON THURSDAY WITH MU CAPES AROUND 2000-3000 JULES. WITH RELATIVELY WEAK SFC-6KM SHEAR AND NEAR MOIST ADIABATIC H7-H5 LAPSE RATES...THE PRIMARY THREAT WILL BE DAMAGING WINDS WITH THE LARGE HAIL THREAT MARGINAL. PRECIPITATION THREAT WILL DIMINISH FROM THE NORTH TO SOUTH ON FRIDAY AS THE COLD FRONT MOVES INTO THE SOUTHERN PLAINS. DB && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. $$ WFO EAX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 1225 PM CDT WED JUL 21 2004 .DISCUSSION... TEMPERATURES ARE SLOWLY CLIMBING SOUTH OF THE MISSOURI RIVER, BUT THICK CIRRUS HAS PREVENTED THE WARM UP NEEDED TO REACH HEAT ADVISORY CRITERIA. TEMPERATURES WILL LIKELY TOP OUT IN THE LOWER 90S IN SEDALIA, WARRENSBURG, CLINTON AND HARRISONVILLE. THAT SHOULD PUT HEAT INDICES AROUND 100 DEGREES FOR AN HOUR OR TWO, WHICH IS WELL SHORT OF CRITERIA (100 DEGREES FOR AT LEAST 3 CONSECUTIVE HOURS). I'LL BE CANCELING THE HEAT ADVISORY SHORTLY. TEMPERATURES WILL BE ADJUSTED DOWN FROM SAINT JOSEPH TO KIRKSVILLE AS WELL. THE LEE SIDE TROUGH AT 850 MB WILL BE A STEADY STATE FEATURE THROUGH THE LATE AFTERNOON KEEPING THE BAND OF SHOWERS AND THUNDERSTORMS OVER NORTHERN KANSAS ONGOING TODAY. KOCH && .PREVIOUS DISCUSSION... 925 AM... RAIN SHOWERS AND THICK CLOUD COVER WILL LIKELY BRING AN EARLY END TO THE HEAT ADVISORY OVER PARTS OF NORTHEAST KANSAS AND NORTHERN MISSOURI. A LONG LOOP OF THE INFRARED SATELLITE OVERLAYED WITH RUC 700 MB TEMPERATURES INDICATES THAT SHOWERS AND THUNDERSTORMS IGNITED ALONG THE EDGE OF THE CAP IN NORTHEAST KANSAS AROUND SUNRISE. THE AXIS OF THE LOW LEVEL JET, BLOWING ABOUT 30 KTS, PROVIDED A GENERALLY FAVORABLE ENVIRONMENT FOR ASCENT, AND IT APPEARS THAT A GRAVITY WAVE OR OUTFLOW BOUNDARY FROM CONVECTION IN NEBRASKA CONTRIBUTED THE MESOSCALE LIFT TO ACTIVATE THE LINE OF STORMS. THE LOW LEVEL JET MAY BE WEAKENING ACCORDING TO 850 MB PROFILER DATA, BUT THE RUC SUGGESTS THAT ITS AXIS WILL LINGER OVER CENTRAL AND EASTERN KANSAS FOR MOST OF THE DAY. I EXPECT AN OVERALL WEAKENING OF CONVECTION, BUT THE DEBRIS WILL LINGER THROUGH AT LEAST THIS MORNING. THE HEAT ADVISORY POSTED OVERNIGHT WAS MARGINAL SO WITHOUT SUNSHINE THIS MORNING, IT WILL BE VERY TOUGH FOR AREAS NORTH OF THE RIVER TO REACH A 105 DEGREE HEAT INDEX FOR THREE HOURS THIS AFTERNOON. I WILL PROBABLY DROP THE ADVISORY FOR A GOOD CHUNK OF THE NORTHERN ZONES AFTER THE 10 AM OBSERVATIONS COME IN. KOCH && 200 AM... HEAT INDICES THE MAIN CONCERN TODAY WITH THE THREAT OF CONVECTION ENTERING THE PICTURE AGAIN LATE TONIGHT THROUGH FRIDAY. EVENING UPPER AIR INDICATED AN UPPER RIDGE ACROSS MUCH OF THE CENTRAL PLAINS WITH A RELATIVELY STRONG CAP FROM KANSAS EAST INTO MISSOURI. CONVECTION CONTINUES AROUND THE PERIPHERY OF THE RIDGE AND ALONG A SURFACE TROUGH LOCATED ACROSS NORTHERN KANSAS. CONVECTION MAINLY MOVING EAST WITH SLOW DEVELOPMENT SOUTH AS AN OUTFLOW BOUNDARY DRIFTS SOUTH. OVERALL...PREFER THE MESOETA SOLUTION THE NEXT COUPLE OF DAYS AS THE MESOETA NOT SUFFERING FROM CONVECTIVE FEEDBACK AS BAD WHEN COMPARED TO THE GFS. MESOETA APPEARS REASONABLE IN DRIFTING THE WEAK SURFACE TROUGH IN NEBRASKA SLOWLY SE INTO SE NEBRASKA THIS AFTERNOON...AS A WEAK UPPER TROUGH PROGRESSES EAST THROUGH THE NORTHERN PLAINS. AHEAD OF THE SURFACE TROUGH...INCREASING SOUTHWEST WINDS WILL INCREASE TEMPERATURES A LITTLE TODAY...AND WITH HIGH DEWPOINTS...MOST OF THE CWA WILL LIKELY REACH OR EXCEED HEAT ADVISORY CRITERIA. THE CAP WEAKENS SLIGHTLY THIS AFTERNOON WITH THE APPROACH OF THE SURFACE TROUGH. ALTHOUGH SHEAR RATHER WEAK...SUFFICIENT INSTABILITY PRESENT FOR A CHANCE OF THUNDERSTORMS LATE THIS AFTERNOON IN EXTREME NORTHWEST MO. SURFACE TROUGH TO ONLY INCH SOUTHEAST THROUGH THE NIGHT...HOWEVER AS THE UPPER FLOW AMPLIFIES ACROSS THE CONUS...A RATHER STRONG AND UNSEASONABLY COOL SURFACE HIGH WILL DRIVE A COLD FRONT INTO NORTHERN MISSOURI ON THURSDAY. AS THE CAP CONTINUES TO WEAKEN...MODERATE TO HIGH INSTABILITY ALONG THE FRONT ALONG WITH HIGH PRECIPITABLE WATER VALUES...WILL LEAD TO A GOOD CHANCE OF THUNDERSTORMS...MAINLY ACROSS THE NORTHERN ONE HALF OF THE CWA DURING THE DAY ON THURSDAY. THE SURFACE FRONT WILL CLEAR THE CWA THURSDAY NIGHT...HOWEVER THE H8 FRONT WILL BECOME NEARLY STATIONARY ACROSS NORTHERN MISSOURI. PINNING DOWN THE EXACT PLACEMENT OF THE SURFACE AND H8 FRONT IS DIFFICULT AND HEAVILY DEPENDENT UPON PREVIOUS CONVECTION AND ANY WEAK SHORTWAVES EMBEDDED IN THE FLOW. AS PER THE MESOETA...WEAK ISENTROPIC LIFT WILL DEVELOP ACROSS THE NRN HALF OF THE CWA THURSDAY NIGHT IN A VERY MOIST SURFACE TO H5 ENVIRONMENT. ALTHOUGH CONFIDENCE IS NOT HIGH...THERE APPEARS TO BE A GOOD THREAT OF RAIN AND CONVECTION WITH PRECIPITABLE WATER VALUES FROM 1.5-2 INCHES AND A FRONT IN THE AREA. THERE WILL ALSO BE A THREAT OF A FEW SEVERE THUNDERSTORMS MAINLY DURING THE AFTERNOON AND EVENING HOURS ON THURSDAY WITH MU CAPES AROUND 2000-3000 JULES. WITH RELATIVELY WEAK SFC-6KM SHEAR AND NEAR MOIST ADIABATIC H7-H5 LAPSE RATES...THE PRIMARY THREAT WILL BE DAMAGING WINDS WITH THE LARGE HAIL THREAT MARGINAL. PRECIPITATION THREAT WILL DIMINISH FROM THE NORTH TO SOUTH ON FRIDAY AS THE COLD FRONT MOVES INTO THE SOUTHERN PLAINS. DB && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. $$ WFO EAX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 925 AM CDT WED JUL 21 2004 .DISCUSSION... RAIN SHOWERS AND THICK CLOUD COVER WILL LIKELY BRING AN EARLY END TO THE HEAT ADVISORY OVER PARTS OF NORTHEAST KANSAS AND NORTHERN MISSOURI. A LONG LOOP OF THE INFRARED SATELLITE OVERLAYED WITH RUC 700 MB TEMPERATURES INDICATES THAT SHOWERS AND THUNDERSTORMS IGNITED ALONG THE EDGE OF THE CAP IN NORTHEAST KANSAS AROUND SUNRISE. THE AXIS OF THE LOW LEVEL JET, BLOWING ABOUT 30 KTS, PROVIDED A GENERALLY FAVORABLE ENVIRONMENT FOR ASCENT, AND IT APPEARS THAT A GRAVITY WAVE OR OUTFLOW BOUNDARY FROM CONVECTION IN NEBRASKA CONTRIBUTED THE MESOSCALE LIFT TO ACTIVATE THE LINE OF STORMS. THE LOW LEVEL JET MAY BE WEAKENING ACCORDING TO 850 MB PROFILER DATA, BUT THE RUC SUGGESTS THAT ITS AXIS WILL LINGER OVER CENTRAL AND EASTERN KANSAS FOR MOST OF THE DAY. I EXPECT AN OVERALL WEAKENING OF CONVECTION, BUT THE DEBRIS WILL LINGER THROUGH AT LEAST THIS MORNING. THE HEAT ADVISORY POSTED OVERNIGHT WAS MARGINAL SO WITHOUT SUNSHINE THIS MORNING, IT WILL BE VERY TOUGH FOR AREAS NORTH OF THE RIVER TO REACH A 105 DEGREE HEAT INDEX FOR THREE HOURS THIS AFTERNOON. I WILL PROBABLY DROP THE ADVISORY FOR A GOOD CHUNK OF THE NORTHERN ZONES AFTER THE 10 AM OBSERVATIONS COME IN. KOCH .PREVIOUS DISCUSSION... 200 AM... HEAT INDICES THE MAIN CONCERN TODAY WITH THE THREAT OF CONVECTION ENTERING THE PICTURE AGAIN LATE TONIGHT THROUGH FRIDAY. EVENING UPPER AIR INDICATED AN UPPER RIDGE ACROSS MUCH OF THE CENTRAL PLAINS WITH A RELATIVELY STRONG CAP FROM KANSAS EAST INTO MISSOURI. CONVECTION CONTINUES AROUND THE PERIPHERY OF THE RIDGE AND ALONG A SURFACE TROUGH LOCATED ACROSS NORTHERN KANSAS. CONVECTION MAINLY MOVING EAST WITH SLOW DEVELOPMENT SOUTH AS AN OUTFLOW BOUNDARY DRIFTS SOUTH. OVERALL...PREFER THE MESOETA SOLUTION THE NEXT COUPLE OF DAYS AS THE MESOETA NOT SUFFERING FROM CONVECTIVE FEEDBACK AS BAD WHEN COMPARED TO THE GFS. MESOETA APPEARS REASONABLE IN DRIFTING THE WEAK SURFACE TROUGH IN NEBRASKA SLOWLY SE INTO SE NEBRASKA THIS AFTERNOON...AS A WEAK UPPER TROUGH PROGRESSES EAST THROUGH THE NORTHERN PLAINS. AHEAD OF THE SURFACE TROUGH...INCREASING SOUTHWEST WINDS WILL INCREASE TEMPERATURES A LITTLE TODAY...AND WITH HIGH DEWPOINTS...MOST OF THE CWA WILL LIKELY REACH OR EXCEED HEAT ADVISORY CRITERIA. THE CAP WEAKENS SLIGHTLY THIS AFTERNOON WITH THE APPROACH OF THE SURFACE TROUGH. ALTHOUGH SHEAR RATHER WEAK...SUFFICIENT INSTABILITY PRESENT FOR A CHANCE OF THUNDERSTORMS LATE THIS AFTERNOON IN EXTREME NORTHWEST MO. SURFACE TROUGH TO ONLY INCH SOUTHEAST THROUGH THE NIGHT...HOWEVER AS THE UPPER FLOW AMPLIFIES ACROSS THE CONUS...A RATHER STRONG AND UNSEASONABLY COOL SURFACE HIGH WILL DRIVE A COLD FRONT INTO NORTHERN MISSOURI ON THURSDAY. AS THE CAP CONTINUES TO WEAKEN...MODERATE TO HIGH INSTABILITY ALONG THE FRONT ALONG WITH HIGH PRECIPITABLE WATER VALUES...WILL LEAD TO A GOOD CHANCE OF THUNDERSTORMS...MAINLY ACROSS THE NORTHERN ONE HALF OF THE CWA DURING THE DAY ON THURSDAY. THE SURFACE FRONT WILL CLEAR THE CWA THURSDAY NIGHT...HOWEVER THE H8 FRONT WILL BECOME NEARLY STATIONARY ACROSS NORTHERN MISSOURI. PINNING DOWN THE EXACT PLACEMENT OF THE SURFACE AND H8 FRONT IS DIFFICULT AND HEAVILY DEPENDENT UPON PREVIOUS CONVECTION AND ANY WEAK SHORTWAVES EMBEDDED IN THE FLOW. AS PER THE MESOETA...WEAK ISENTROPIC LIFT WILL DEVELOP ACROSS THE NRN HALF OF THE CWA THURSDAY NIGHT IN A VERY MOIST SURFACE TO H5 ENVIRONMENT. ALTHOUGH CONFIDENCE IS NOT HIGH...THERE APPEARS TO BE A GOOD THREAT OF RAIN AND CONVECTION WITH PRECIPITABLE WATER VALUES FROM 1.5-2 INCHES AND A FRONT IN THE AREA. THERE WILL ALSO BE A THREAT OF A FEW SEVERE THUNDERSTORMS MAINLY DURING THE AFTERNOON AND EVENING HOURS ON THURSDAY WITH MU CAPES AROUND 2000-3000 JULES. WITH RELATIVELY WEAK SFC-6KM SHEAR AND NEAR MOIST ADIABATIC H7-H5 LAPSE RATES...THE PRIMARY THREAT WILL BE DAMAGING WINDS WITH THE LARGE HAIL THREAT MARGINAL. PRECIPITATION THREAT WILL DIMINISH FROM THE NORTH TO SOUTH ON FRIDAY AS THE COLD FRONT MOVES INTO THE SOUTHERN PLAINS. DB && .EAX WATCHES/WARNINGS/ADVISORIES... KS...HEAT ADVISORY THROUGH EARLY THIS EVENING FOR ALL ZONES.. MO...HEAT ADVISORY THROUGH EARLY THIS EVENING FOR ALL ZONES. $$ WFO EAX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 343 PM CDT WED JUL 21 2004 .SHORT TERM... BROAD UPPER LEVEL TROUGH WAS OVER THE NORTHERN PLAINS AND CENTRAL CANADA. A SHORT WAVE TROUGH EXTENDED INTO EASTERN ND. WATER VAPOR LOOP SHOWS STORMS IN NORTHWEST ZONES WERE OCCURRING NEAR A CIRCULATION CENTER. SOME DRYING/DARKENING NOTED ACROSS NORTHERN MN AND NORTHERN ND. STORMS TO THE SOUTH SHOULD BE IN THE RIGHT ENTRANCE REGION OF JET. 850 HPA THETA-E RIDGE OVER EASTERN SD WILL SHIFT EAST TONIGHT. RUC INDICATING ABOUT 2500 J/KG MUCAPES IN THE SOUTHERN ZONES THIS AFTERNOON WHICH SHIFT SOUTHEAST THIS EVENING. WEAK SURFACE LOW WAS OVER FAR SOUTHEAST ND WITH UPPER 60S DEWPOINTS OVER EASTERN SD. UPPER 50S ACROSS SOUTHEAST ND AND 40S TO THE WEST. DEWPOINTS WERE ALSO POOLING ACROSS NORTHEAST ND AND NORTHWEST MN. NEXT SHORT WAVE TROUGH MOVES THROUGH THURSDAY AFTERNOON BUT CAPES ARE LOW. STEEP LAPSE RATES EXPECTED SATURDAY AFTERNOON AND EVENING WITH COLD AIR ALOFT AND RELATIVELY HIGH LOW LEVEL MOISTURE. WILL ADD A CHANCE OF PRECIPITATION FOR FRIDAY AFTERNOON AND NIGHT. .LONG TERM... LONGWAVE PATTERN NOT CHANGING MUCH IN SPITE OF THE SHORTWAVE BECOMING MORE DOMINANT HERE NEXT SEVERAL DAYS WITH NORTHWEST FLOW. FLAT RIDGE ACROSS MOST OF LOWER 48 WILL RETURN TEMPERATURES ALMOST TO SEASONAL LEVELS EARLY NEXT WEEK AFTER A LARGE LOW LEVEL RIDGE FINALLY NUDGES EAST. BUT NEITHER GFS/ECMWF PUSH SUBTROPICAL MOISTURE BACK NORTH ON A LOW LEVEL JET THROUGH WED. ECMWF DOES SHOW A WEAK JET MOVING +10C 850 MB DEW POINTS NORTHWARD INTO THE REGION LATE TUE/WED. THINK MOISTURE TRANSPORT MAY BE UNDERDONE IN THIS MODEL BUT IT AND GFS ARE OUT OF PHASE WITH THE SHORTWAVE PATTERN BY THEN WITH GFS BEING THE SLOWER. HAVE INCLUDED CHANCE THUNDER FOR WED AFTERNOON AND NIGHT AND WILL LOOK FOR BETTER AGREEMENT LATER. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ HOPPES/GV nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 155 PM EDT WED JUL 21 2004 .AVIATION... THERE WAS SOME SCT-BKN CU AROUND THE AREA TODAY. ETA FCST SNDGS SHOW A MID LEVEL CAP THIS AFTERNOON. NOT MUCH FORCING IN ADVANCE OF AN APPROACHING PRE-FRONTAL TROF & S/W THIS AFTERNOON AND EVENING...ALTHOUGH ISOLATED STORMS ARE POSSIBLE. THIS FEATURE WILL LIKELY LEAD TO MORE ORGANIZED CONVECTION DEVELOPING LATE OVERNIGHT INTO EARLY THURSDAY ACROSS THE TAF SITES...WITH THE BETTER FORCING AT KDAY AND KCMH. && .PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 1055 AM EDT WED JUL 21 2004 SHORT TERM (TODAY)... THE FCST AREA WAS STILL MOSTLY SUNNY THIS MORNING. THE MODIFIED 12Z ILN SNDG REMAINS CAPPED BUT THE 12Z ETA SHOWS SOME PVA MOVING ACROSS THE WEST BY 18Z. HOWEVER...THE RUC IS WEAKER WITH THIS FEATURE. STILL...ISOLATED STORMS LOOK PLAUSIBLE. FCST TEMPS ALSO APPEAR FINE...SO WILL UPDATE TO REMOVE MORNING WORDING ONLY. PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 405 AM EDT WED JUL 21 2004 SHORT TERM (TODAY THROUGH THURSDAY NIGHT)... A LOT OF UNCERTAINTY IN THE FORECAST WITH SFC LOW MOVING THROUGH THE GREAT LAKES REGION THURSDAY. MAIN ENERGY IS CONCENTRATED TO THE NORTH BUT COLD FRONTAL PASSAGE WILL BE MOVING THROUGH THE AREA WHICH SHOULD BE PRIMED WITH GULF MOISTURE. INCREASED HUMIDITIES WILL BE THE RULE TODAY AND TONIGHT...AND HEAT INDICIES WILL RISE TO THE UPPER 90S AND TOP 100 IN A FEW ISOLATED SPOTS TODAY AND TOMORROW. DEPENDING ON FORCING MECHANISMS AVIALALBE TODAY AND TONIGHT...SHOWERS AND THUNDERSTORMS ARE EXPECTED TO SPARK IN THE WARM SECTOR AHEAD OF COLD FRONT. GFS IS DRY AT THIS TIME AND THE TREND OF THINKING IS IN THIS DIRECTION. HOWEVER...SOLUTION FROM THE ETA REGARDING QPF IS OVERDONE BUT NOT OUT OF THE QUESTION TONIGHT. PREVIOUS RUNS FROM BOTH THE GFS AND ETA SHOWED AN INCREASED AREA OF ACTIVITY IN SWRN FCST AREA DURING THIS TIME FRAME...BUT IT WILL DEPEND PRIMARILY ON WHERE CONVECTION MAY OR MAY NOT SPARK THIS AFTERNOON/EARLY EVENING. IF CONVECTION HOLDS OFF TODAY...I DOUBT THAT ANY WILL FIRE TONIGHT AND GFS WILL BE CORRECT. SUBSEQUENT SHIFTS WILL HAVE TO RE-EVALUATE SCENARIO AS TIME PROGRESSES. ANY STORMS THAT DEVELOP WILL BE IN A PRIME AIRMASS WITH PWATS AS HIGH AS 2 1/4" EARLY THURSDAY RIGHT AHEAD OF THE FRONT. MAIN THREAT FOR SEVERE WILL BE WITH FROPA ON THURS. SBCAPES RISE OVER 3000J/KG AHEAD OF FRONT...AND LI'S ARE ALL NEGATIVE. HAVE NOT CHANGED TEMPERATURES BY MUCH IN ANY PERIOD. TEMP FCSTS WILL HAVE TO BE LOOKED AT WITH SAME REASONING ON EVALUATION OF PRECIP TODAY AND TOMORROW. LARGER SWATH OF RAIN WILL CUT VALUES BUT AM HEDGING ATTM TOWARDS A DRIER...WARMER SOLUTION. PREVIOUS DISCUSSION... LONG TERM (FRIDAY THROUGH TUESDAY)... FOR FRIDAY...THE LATEST GFS AND ECMWF SHOW THE COLD FRONT SOUTH OF THE FCST AREA BY 12Z WHILE THE ETA IS MUCH SLOWER WITH FEATURE...VIRTUALLY STALLING ACROSS CENTRAL OHIO THROUGH 18Z. ALSO...THE ETA SHOWS A SHARP TEMPERATURE GRADIENT ACROSS THE FRONT AND SFC BASED CAPES OVER 3000 J/KG. THE GFS OFTEN PUSHES FRONTS THROUGH TOO FAST THIS TIME OF THE YEAR...SO WILL RESPECT THE ETA SCENARIO. OBVIOUSLY...POPS AND TEMPS WILL BE PROBLEMATIC. WILL KEEP CHANCE POPS THROUGH THE DAY FRIDAY...WITH THE BEST CHANCE IN THE SOUTH. IN ADDITION...WILL BUMP UP HIGH TEMPS SOMEWHAT. HOWEVER...IT COULD BE MUCH WARMER IN THE SOUTH IF THE ETA IS CORRECT. HIGH PRESSURE WILL BEGIN TO BUILD INTO THE AREA FROM THE NORTH FRIDAY/FRIDAY NIGHT WITH DRY WEATHER AND BELOW NORMAL TEMPERATURES STILL EXPECTED FOR THE WEEKEND. THE NEXT MAJOR SYSTEM APPROACHES THE AREA NEXT TUESDAY INTO WEDNESDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. IN...NONE. KY...NONE. && $$ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 1055 AM EDT WED JUL 21 2004 SHORT TERM (TODAY)... THE FCST AREA WAS STILL MOSTLY SUNNY THIS MORNING. THE MODIFIED 12Z ILN SNDG REMAINS CAPPED BUT THE 12Z ETA SHOWS SOME PVA MOVING ACROSS THE WEST BY 18Z. HOWEVER...THE RUC IS WEAKER WITH THIS FEATURE. STILL...ISOLATED STORMS LOOK PLAUSIBLE. FCST TEMPS ALSO APPEAR FINE...SO WILL UPDATE TO REMOVE MORNING WORDING ONLY. && .PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 740 AM EDT WED JUL 21 2004 AVIATION... MVFR FOG SHOULD LIFT BY 13Z. EXCEPTION WILL BE IFR VALLEY FOG AT KLUK...WHICH COULD LAST TIL 14Z. H5 PVA PUSHES INTO WESTERN SECTIONS AFTER 18Z. VORT COMBINES WITH MODERATELY UNSTABLE...LI OF -2 TO -3 CAPES AROUND 1000 J/KG. COULD SEE SCATTERED TSRA AS EARLY AS 16Z...BUT FOCUSED TIMING IN TAFS TO LATE AFTERNOON WHEN FEEL THAT THERE IS THE BEST CHANCE. LEANED TOWARDS ETA/NGM SOLUTION FOR TONIGHT WHICH BRINGS IN AREA OF CONVECTION MAINLY AFTER 6Z. SITES .PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 405 AM EDT WED JUL 21 2004 SHORT TERM (TODAY THROUGH THURSDAY NIGHT)... A LOT OF UNCERTAINTY IN THE FORECAST WITH SFC LOW MOVING THROUGH THE GREAT LAKES REGION THURSDAY. MAIN ENERGY IS CONCENTRATED TO THE NORTH BUT COLD FRONTAL PASSAGE WILL BE MOVING THROUGH THE AREA WHICH SHOULD BE PRIMED WITH GULF MOISTURE. INCREASED HUMIDITIES WILL BE THE RULE TODAY AND TONIGHT...AND HEAT INDICIES WILL RISE TO THE UPPER 90S AND TOP 100 IN A FEW ISOLATED SPOTS TODAY AND TOMORROW. DEPENDING ON FORCING MECHANISMS AVIALALBE TODAY AND TONIGHT...SHOWERS AND THUNDERSTORMS ARE EXPECTED TO SPARK IN THE WARM SECTOR AHEAD OF COLD FRONT. GFS IS DRY AT THIS TIME AND THE TREND OF THINKING IS IN THIS DIRECTION. HOWEVER...SOLUTION FROM THE ETA REGARDING QPF IS OVERDONE BUT NOT OUT OF THE QUESTION TONIGHT. PREVIOUS RUNS FROM BOTH THE GFS AND ETA SHOWED AN INCREASED AREA OF ACTIVITY IN SWRN FCST AREA DURING THIS TIME FRAME...BUT IT WILL DEPEND PRIMARILY ON WHERE CONVECTION MAY OR MAY NOT SPARK THIS AFTERNOON/EARLY EVENING. IF CONVECTION HOLDS OFF TODAY...I DOUBT THAT ANY WILL FIRE TONIGHT AND GFS WILL BE CORRECT. SUBSEQUENT SHIFTS WILL HAVE TO RE-EVALUATE SCENARIO AS TIME PROGRESSES. ANY STORMS THAT DEVELOP WILL BE IN A PRIME AIRMASS WITH PWATS AS HIGH AS 2 1/4" EARLY THURSDAY RIGHT AHEAD OF THE FRONT. MAIN THREAT FOR SEVERE WILL BE WITH FROPA ON THURS. SBCAPES RISE OVER 3000J/KG AHEAD OF FRONT...AND LI'S ARE ALL NEGATIVE. HAVE NOT CHANGED TEMPERATURES BY MUCH IN ANY PERIOD. TEMP FCSTS WILL HAVE TO BE LOOKED AT WITH SAME REASONING ON EVALUATION OF PRECIP TODAY AND TOMORROW. LARGER SWATH OF RAIN WILL CUT VALUES BUT AM HEDGING ATTM TOWARDS A DRIER...WARMER SOLUTION. PREVIOUS DISCUSSION... LONG TERM (FRIDAY THROUGH TUESDAY)... FOR FRIDAY...THE LATEST GFS AND ECMWF SHOW THE COLD FRONT SOUTH OF THE FCST AREA BY 12Z WHILE THE ETA IS MUCH SLOWER WITH FEATURE...VIRTUALLY STALLING ACROSS CENTRAL OHIO THROUGH 18Z. ALSO...THE ETA SHOWS A SHARP TEMPERATURE GRADIENT ACROSS THE FRONT AND SFC BASED CAPES OVER 3000 J/KG. THE GFS OFTEN PUSHES FRONTS THROUGH TOO FAST THIS TIME OF THE YEAR...SO WILL RESPECT THE ETA SCENARIO. OBVIOUSLY...POPS AND TEMPS WILL BE PROBLEMATIC. WILL KEEP CHANCE POPS THROUGH THE DAY FRIDAY...WITH THE BEST CHANCE IN THE SOUTH. IN ADDITION...WILL BUMP UP HIGH TEMPS SOMEWHAT. HOWEVER...IT COULD BE MUCH WARMER IN THE SOUTH IF THE ETA IS CORRECT. HIGH PRESSURE WILL BEGIN TO BUILD INTO THE AREA FROM THE NORTH FRIDAY/FRIDAY NIGHT WITH DRY WEATHER AND BELOW NORMAL TEMPERATURES STILL EXPECTED FOR THE WEEKEND. THE NEXT MAJOR SYSTEM APPROACHES THE AREA NEXT TUESDAY INTO WEDNESDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. IN...NONE. KY...NONE. && $$ oh AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 947 PM EDT WED JUL 21 2004 .SHORT TERM (REST OF TONIGHT)... RUC AND MESOETA SHOWING H5 VORT MAX PUSHING INTO THE NC MTNS ATTM. WEAK UPSLOPE AND INSTABILITY ALONG WITH THE PVA HAS RESULTED IN A FEW SH AND ISO TS THIS EVENING. I DO EXPECT THAT THE CONVECTION WILL ASH OUT BY MIDNIGHT AS THE SHOWERS PUSH OFF THE HIGHER TERRAIN AND THE BL COOLS. I WILL ADD CHC POPS FOR THE AFFECTED AREAS ALONG THE ESCARPMENT. ALSO...ADJUSTED THE T/TD DOWN ALONG WITH THE SKY TO MATCH CONDITIONS. WILL ADD THE MENTION OF PATCHY DENSE VALLEY FOG AS PATTERN WILL REMAIN FAVORABLE OVERNIGHT...ESPECIALLY IN AREAS WITH EVENING RAINFALL. && .PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 255 PM EDT WED JUL 21 2004 SHORT TERM (TONIGHT THROUGH SATURDAY)... WILL CALL IT MOSTLY CLEAR FOR TONIGHT AS CU SHOULD DISSIPATE THIS EVENING WITH JUST SOME DEBRIS CI EXPECTED OVERNIGHT. ON THURSDAY... SHORT RANGE MODELS HAVE SOMEWHAT OF HANDLE ON VORT...PROBABLY OF CONVECTIVE ORIGIN...DROPPING THRU WITHIN NORTHERLY FLOW. TIMING OF BEST LIFT LOOKS TO BEGIN IN THE AFTERNOON AND BE ACRS MY NC ZONES. ENOUGH CONSISTENCY AND DYNAMICS ASSOCIATED WITH THIS FEATURE MAY SUPPORT LIKELY CVRG AT SOME POINT ACRS THE NW ZONES...BUT KEPT GOING HIGH CHC WITH THE THREAT OF DOWNSLOPE FLOW DEVELOPING. AFTER A LULL THURSDAY NIGHT IN WAKE OF AFOREMENTIONED WAVE WILL RAMP POPS BACK UP INTO CHC CATEGORY FOR FRIDAY WITH GFS/ETA BLEND WRT MOISTURE AND PCPN FIELDS OUT AHEAD OF APPROACHING COLD FRONT WHICH IS PROGGED TO MOVE EAST OF THE CWFA BY 12Z SATURDAY. LONG TERM (SATURDAY NIGHT THROUGH WEDNESDAY)... MEDIUM RANGE MDLS STILL SUGGESTING SOME SORT OF COLD AIR DAMMING TO DEVELOP BY SUNDAY AFTER COLD FRONT PASSAGE...AND CONTINUING THRU TUESDAY BEFORE NEXT COLD FRONT SCOURS THE COLD DOME BY LATE WEDNESDAY. THIS SCENARIO DOES APPEAR TO BE MORE LIKELY WITH MDLS MOVING SFC HIGH PRESSURE OVER NEW ENGLAND UNDER H5 CONFLUENT ZONE. FCST H85 WINDS NOW SELY WITH GOOD MOISTURE FETCH OFF THE ATLANTIC AND U SHAPED ISOBARS/THICKNESS LINES ALSO GOOD INDICATORS. INVERTED SFC TROF TO OUR WEST WITH LOW FORMING ALONG STALLED SFC FNT OVER THE GULF WOULD ALSO HELP MOISTURE TRANSPORT INTO THE AREA FROM THE GULF. FOLLOWED THIS TREND...BUT DID NOT GO AS LOW WITH MAX TEMPS OR AS HIGH WITH POP AS IN THE OPERATIONAL MOS GUIDANCE. WENT CLOSER TO ENSEMBLE MEAN WHICH IS STILL SIGNIFICANTLY BELOW NORMAL FOR MAX TEMPS. TRENDED TOWARD PRECIP EACH PERIOD WITH CHC AFT/EVE POP AND SLIGHT CHC OVERNIGHT/MORNING POP. ALSO INCREASED CLOUD COVER THRU THE PERIOD. ALL THAT SAID...WILL HAVE TO WATCH THIS CLOSELY. IF IT UNFOLDS AS MDLS SUGGESTING...MAX TEMPS WILL NEED TO BE LOWER AND POP WILL NEED TO BE HIGHER...WITH A THREAT OF SIGNIFICANT RAINFALL AMOUNTS. AVIATION... SCT CU THIS AFTERNOON WILL DISSIPATE JUST AFTER SUNSET. RADIATIONAL CONDITIONS NOT AS IDEAL AS PREVIOUS DAYS...BUT HAZE LIKELY FOR A FEW HOURS NEAR DAYBREAK. WENT MVFR FOR KAND/KCLT AND KAVL WHERE VSBY RESTRICTIONS MOST LIKELY. MVFR POSSIBLE AT THE OTHER SITES BUT HELD OFF FOR NOW. SOME CONVECTIVE DEBRIS CLOUDS MAY MOVE IN LATE TONIGHT BUT SHOULD REMAIN SCT THRU THE MORNING. CU DEVELOPS AGAIN THU MORNING. INCREASED CLOUDS POSSIBLE LATE MORNING AHEAD OF SYSTEM APPROACHING THE AREA...BUT DID NOT ADD NEW FM GROUP SINCE NO CATEGORY CHANGE. CONVECTION POSSIBLE THU...BUT ANY OCCURRENCES WILL BE AFTER 18Z. WINDS LIGHT AND VARIABLE THRU THE PERIOD. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SHORT TERM (UPDATE)...NED sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 915 PM EDT WED JUL 21 2004 .SHORT TERM /TONIGHT/...NO UPDATE NEEDED EXCEPT TO REMOVE SOME EVENING WORDING. DRY MID LEVELS KEPT MOST OF THE CONVECTION AT BAY THIS AFTERNOON ALTHOUGH SOME SHOWERS WERE ABLE TO FIRE ALONG THE SEABREEZE AND OUTFLOW BOUNDARIES. THIS ACTIVITY HAS ALL DISSIPATED AND MOSTLY CLEAR SKIES SHOULD PREVAIL FOR THE REMAINDER OF THE NIGHT. WILL LOOK FOR A REPEAT OF SOME FOG MAINLY OVER THE COASTAL AREAS OF SC. THIS IS ALREADY MENTIONED IN THE ZONES AND MANY STATIONS ARE ALREADY DOWN TO 3 AND 4SM BECAUSE OF THE AFTERNOON HAZE. && .MARINE...BASED ON THE LATEST RUC WILL WORD SOME OFFSHORE WIND AFTER MIDNIGHT. GFS DID A SUPERIOR JOB YESTERDAY WITH THE NORTHERLY WINDS OVER THE WATER THIS MORNING...AND LIGHT OFFSHORE FLOW IS FORECAST ONCE AGAIN. SEAS AROUND 2 FEET WILL CONTINUE. && .AVIATION...SKC OVERNIGHT WITH MENTION OF 2SM BR FOR CHS. SAV SHOULD REMAIN MOSTLY CLEAR OVERNIGHT WITH NO VISBY PROBLEMS. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ PM/HSA sc AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 955 AM EDT WED JUL 21 2004 .SHORT TERM (REST OF TODAY)... MODIFIED 12Z AREA SNDGS DID YIELD SOME WEAK INSTABILITY THIS AFTERNOON BUT WARM MID-LVLS RESULTED IN CAP WITH INVERSION NOTED FROM 700-600 MB ON KFFC SNDG. THIS WAS NOT APPARENT ON THE KGSO SNDG THOUGH...BUT LACK OF TRIGGERING MECHANISM AND LOWER THAN NORMAL SFC DWPTS EXPECTED TO KEEP DEEP CONVECTIVE CHANCES QUITE LOW. BOTH THE RUC AND 06Z ETA EJECT A WEAK VORT SE WITH SOME RESULTANT DPVA INTO THE NC MTNS THIS AFTERNOON...BUT IT IS STILL INCONCLUSIVE WHETHER THIS FEATURE CAN AID IN GENERATION OF ANYTHING MORE THAN GOING ISOLATED RIDGETOP DEEP CONVECTION AS CURRENTLY ADVERTISED. ANALYZED 12Z LLVL THICKNESS VALUES SUPPORT GOING MAXES. && .PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 351 AM EDT WED JUL 21 2004 SHORT TERM (TODAY THROUGH THURSDAY NIGHT)... CONFIDENCE IS FAIRLY HIGH TODAY THAT CONVECTION WILL BE ABOUT AS SPARSE AS YESTERDAY...WITH MINIMAL LOW LEVEL MOISTURE AND A SIGNIFICANT MID LEVEL CAP SHOWING UP ON FORECAST SOUNDINGS. CAP COULD PERHAPS BE BROKEN WITH OROGRAPHIC ASCENT TOWARD EVENING...BUT BY THEN BOUNDARY LAYER WILL BE STABILIZING. KEPT FORECAST DRY TODAY BUT KEPT THE SLIGHT CHANCES FOR THE HIGHER TERRAIN. BUMPED TEMPERATURES ABOUT A DEGREE IN THE NORTH CAROLINA PORTION OF OUR FORECAST AREA. ETA AND GFS CONTINUE TO PUSH OUR EASTERN TROF TO THE COAST AND ALLOW RIDGING ALOFT TO BUILD EAST. GFS PRODUCES A CURIOUS VORT CENTER DROPPING DOWN INTO OUR AREA IN A WEAKNESS IN THE TRANSITIONING UPPER FLOW; DOES NOT APPEAR MOISTURE WILL BE SUFFICIENT FOR THIS TO PRODUCE CONVECTION BUT WILL WAIT AND SEE WHAT THE 06Z GFS RUN DOES WITH THE FEATURE. CONFIDENCE DETERIORATES STARTING TONIGHT. CWFA REMAINS ON THE EASTERN PERIPHERY OF THE UPPER RIDGE...WHICH GETS SLOWLY SQUASHED WITH SHORTWAVES ROTATING ACROSS THE SOUTHEAST STATES. COLD FRONT ALSO PROGD TO APPROACH FOR LATE IN THE SHORT TERM PERIODS...PRECEDED BY A FAIRLY WELL-DEFINED LEE TROF. MOISTURE SHOULD ALSO BE ON THE INCREASE STARTING THURSDAY. ETA HAS SEEMED OVERLY HYPER OF LATE IN PRODUCING LARGE CLUSTERS OF CONVECTION IN LATTER PERIODS; IT PRODUCES ONE CLOSE TO THE CWFA LATE TONITE. TRENDS WITH THE UPPER PATTERN HAS BEEN A SLOWER EVOLUTION THAN PROGD BY THE MODELS. WE WILL KEEP THE OVERNIGHT DRY...AND BRING CHANCE OF CONVECTION INTO THE NORTHWEST EARLY THURSDAY. IT IS WITH THE THURSDAY TIME FRAME THAT THE MODELS REALLY BEGIN TO DIVERGE. WHILE THE GFS AND CANADIAN CONTINUE TO PUSH THE OLD EASTERN TROF EVEN MORE TO THE EAST AND GRADUALLY CUT OFF A LOW OFF THE EASTERN SEABOARD...AND FAR REMOVED FROM THE WESTERLIES...ETA KEEPS THE OLD TROF CLOSE TO THE COAST...CLOSES OFF ANOTHER LOW IN THE TROF...THEN RETROGRADES THE ENTIRE SYSTEM BACK INTO THE COASTAL PLAIN. SUCH ATMOSPHERIC ACROBATICS WOULD BE HIGHLY UNUSUAL THIS TIME OF YEAR. AND OF COURSE...SUCH LARGE DISPARITIES ALOFT RESULT IN A WIDE RANGE OF SURFACE SOLUTIONS...ALTHOUGH BOTH ETA AND GFS/CANADIAN SIMILAR THURSDAY AFTERNOON. WE WILL KEEP SCATTERED CONVECTION IN THE FORECAST THURSDAY. ETA BRINGS A POTENT VORT INTO THE NORTHWEST LATE THURSDAY AFTERNOON WHILE GFS SHOWS AN ELONGATED VORT LOBE OVER THE REGION THAT PERIOD. IN ANY EVENT...IT APPEARS BEST CHANCE OF CONVECTION NOW PUSHED BACK TO THURSDAY AFTERNOON FOR THE SOUTHERN ZONES...AND DESPITE INCREASED MOISTURE AND PRESENCE OF SYNOPTIC FEATURES...WE WENT WITH THE WARMER GUIDANCE TEMPERATURES THAT SHOULD BE ATTAINABLE WITH WESTERLY FLOW IN THE SOUTH. LONG TERM (FRIDAY THROUGH TUESDAY)... MODEL DIVERGENCE FRIDAY AND SATURDAY RESULTED IN FEW CHANGES BEING MADE IN THE LONG TERM. ETA...WITH ITS RETROGRADE MOTION ALOFT... RESULTS IN DEEP UPGLIDE INTO THE CWFA AND AN INCREASING EASTERLY FLOW WHILE GFS...WITH A MORE NORMAL UPPER CLOSED LOW...SUGGESTS A LIGHT NORTHWEST FLOW REGIME WITH STILL ABUNDANT LOW LEVEL MOISTURE FOR FRIDAY. WE KEPT CHANCE OF SHOWERS AND THUNDERSTORMS...AND LOWERED TEMPERATURES NORTH. CANADIAN...GFS AND ETA STILL HINT AT A HIGHLY IRREGULAR JULY PATTERN FOR THE WEEKEND...WITH SURFACE HIGH PRESSURE BUILDING DOWN THE EASTERN SEABOARD AND A WINTRY-LOOKING SURFACE CONFIGURATION ALONG THE COAST; ETA LOOKS EVEN MORE SUSPICIOUS SATURDAY WITH RETROGRADE LOW/TROF PUSHING BACK INTO THE CAROLINAS AND RESULTANT SURFACE STORM SHUNTED TO EXTREME SOUTHERN SOUTH CAROLINA AND GEORGIA. LOTS OF UNCERTAINTY IN THE LONGER TERM SO WE MADE FEW CHANGES BEYOND FRIDAY...MOSTLY TO BUMP UP SKY COVER IN THE EAST AND SOUTH. AVIATION... SIMILAR RADIATING CONDITIONS AS LAST NIGHT SHOULD PRODUCE MVFR RANGE VSBY ACROSS MOST TAF LOCATIONS AROUND DAYBREAK. WIND PROFILES WILL REMAIN QUITE LIGHT TODAY AND AREA FORECAST SOUNDINGS LOOK TO BE FAIRLY WELL CAPPED TO LIMIT CONVECTIVE CHANCES LATE TODAY. FEW CU ARE EXPECTED IN THE 5 TO 6 KFT LAYER...WITH SOME CONVECTIVE HIGH CLOUD DEBRIS POSSIBLE LATE DAY. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SHORT TERM (UPDATE)...CSH sc AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 825 PM MDT WED JUL 21 2004 .DISCUSSION...LATEST SFC ANALYSIS SHOWS HIGH PRESSURE CENTER BUILDING SEWD FM SRN ALTA...WITH NLY BL FLOW ACRS ENTIRE CWFA. WATER VAPOR REVEALS DRY WLY FLOW ALOF ATTM...BUT MID LVL MOISTURE WILL INCREASE SOON IN RESPONSE TO DIURNAL CONVECTION FM NV THRU WRN WY. 00Z SOUNDINGS AND RUN ANALYSIS PLACE 80-90KT JET FM NRN MT THRU NRN MN...AND THIS JET IS PROGGED TO SAG SOUTH OVERNIGHT PLACING NERN WY AND SWRN SD UNDER RIGHT-REAR QUAD AND 300MB DIVERGENCE BULLS-EYE. BOTH RUC/ETA SUGGEST INCREASING MID-LVL FRONTOGENESIS AND ARE BOTH GENERATING PCPN ACRS THIS SAME AREA. THESE INGREDIENTS MAY COME TOGETHER TO PRODUCE LATE NIGHT/EARLY MORNING CONVECTION OVER OUR SWRN ZONES. CURRENT FCST HANDLES THIS WELL AND WILL MAKE ONLY MINOR ADJUSTMENTS. WILL CONT TO MONITOR IN CASE POPS NEED TO BE INCREASED. && UNR WATCHES/WARNINGS/ADVISORIES... .SD...NONE. .WY...NONE. $$ JOHNSON sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SALT LAKE CITY UT 305 PM MDT WED JUL 21 2004 .SYNOPSIS...A GRADUAL DRYING TREND WILL PERSIST INTO THE WEEKEND AS A MORE WESTERLY FLOW REMAINS OVER THE AREA. && .DISCUSSION...BIG PICTURE...THE LARGER SCALE PATTERN HAS CHANGED WITH THE UPPER LEVEL HIGH CENTER NOW CLOSER TO SOUTH CENTRAL ARIZONA INSTEAD OF NEW MEXICO. RESULT IS THE MONSOON PLUME IS NOW ORIENTED MORE SW/NE AND JUST CLIPS THE SE CORNER OF UTAH. A WESTERLY FLOW AND EVEN SOME NW FLOW HAS BECOME ESTABLISHED OVER THE N. ROCKIES. THE SW FLOW AND THE WNW FLOW COME TOGETHER OVER N/CENTRAL UTAH. THIS PATTERN WITH THE RESULTING CONFLUENCE ZONE ARE FORECAST BY ALL MODELS TO REMAIN IN PLACE AT LEAST THROUGH THE WEEKEND AND PERHAPS LONGER. THE ABOVEMENTIONED PATTERN CHANGE HAS RESULTED IN SIGNIFICANT DRYING...ESPECIALLY AT LOW LEVELS AND PARTICULARLY OVER THE SOUTH WHERE DEWPOINGS ARE NOW IN THE 30S. A POCKET OF HIGHER MOISTURE REMAINS OVER THE NW...BUT WITH PW VALUES LESS THAN .75 ITS QUITE A BIT DRIER THAN THE LAST 10 DAYS. SOUDINGS ARE GRADUALLY MOVING TOWARDS AN INVERTED V TYPE...SO WITH EACH DAY TREND SHOULD BE FOR MORE MICROBURST WINDS AND LESS HEAVY RAIN FROM STORMS. CONVECTION IN CENTRAL NV THIS AFTERNOON IS DYNAMICALLY SUPPORTED AS 300 MB RUC SHOWS A WELL DEFINED VORT CENTER ASSOCIATED WITH THIS ACTIVITY. THIS FEATURE WILL MOVE INTO WESTERN UT THIS EVENING AND LIKELY WILL KEEP THUNDERSTORMS GOING PAST DARK OVER THE NORTHERN AND CENTRAL AREAS. ON THURSDAY THE REMAINS OF THIS VORTICITY LOBE LIES OVER SOUTHERN UT...BUT WITH A LESS FAVORABLE AIRMASS. AS AIRMASS DRIES MAX TEMPS SHOULD RISE TO AT LEAST NEAR SEASONAL AVERAGE VALUES...WITH MIN TEMPS DROPPING BACK TO AVERAGE OR EVEN SOMEWHAT BELOW...ESPECIALLY IN THE HIGH COUNTRY WHERE RECENT MOIST AIRMASS HAS KEPT MIN TEMPS QUITE HIGH. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...NONE. WY...NONE. ID...NONE. && $$ DUNN ut AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 357 AM MDT THU JUL 22 2004 .SHORT TERM (TODAY THROUGH FRIDAY)... A WEAK VORT MAX IS ASSOCIATED WITH CONVECTIONG ALONG CENTRAL UT/CO BORDER WITH A LINE OF SHOWERS AND ISOLD TSTMS OVER THE TAVAPUTS PLATEAU. RUC SHOWS THIS FEATURE WELL AS MOVES EAST THEN SOUTHEAST THIS MORNING. MAY BE A MINOR FOCUS FOR CONVECTION OVER LA SAL AND SAN JUAN MTS THIS AFTERNOON. A STRING OF SMALL VORT MAXES IN A WEAK BAROCLINIC ZONES WILL STRETCH ACROSS XTRM NE UT AND SW WY TODAY. ISOLD CONVECTION STILL ACTIVE BENEATH THIS FEATURE EARLY THIS MORNING. A STRONGER FRONT OVER NW WY WILL MOVE SE TODAY AND PUSH THIS UT/WY BAROCLINIC ZONE A BIT FURTHER SOUTH AND EAST. EXPECT THIS FEATURE TO PROVIDE UPLIFT FOR SCATTERED THUNDERSTORMS TODAY IN THE EXTREME NORTH...THOUGH MAINLY OVER THE MOUNTAINS. WEAK ZONE FLOW CONTINUES TONIGHT THROUGH FRIDAY...AS RIDGE REMAIN SUPPRESSED TO THE SOUTHWEST. THIS WILL CONTINUE THE DRYING TREND RESULTING IN THUNDERSTORMS BECOMING MUCH MORE DIURNAL AND OROGRAPHIC IN NATURE. TEMPERATURES WILL CONTINUE AT NEAR PERSISTENCE AND MADE ONLY MINOR ADJUSTMENTS TO THE CURRENT FORECAST. ADJUSTED PREDICTED RH VALUES AND DEW POINTS TO REFLECT DRIER CONDITIONS TODAY AND TONIGHT. .LONG TERM (FRIDAY NIGHT THROUGH WEDNESDAY)...MODELS HAVE BACKED OFF THE DRYING TREND AT LEAST THROUGH THE WEEKEND. BROAD HIGH PRESSURE WITH WEAK FLOW WILL BE SPREAD ACROSS THE SOUTHERN HALF OF NORTH AMERICA KEEPING MOISTURE TRAPPED OVER THE REGION. BY EARLY NEXT WEEK DRIER NORTHWEST FLOW WILL MOVE OVER THE FORECAST AREA TEMPORARILY AS THE HIGH BUILDS OVER AZ/SOUTHERN CA. IT THEN MOVES BACK OVER THE FORECAST AREA BEFORE MIDWEEK. HAVE MADE LITTLE TO NO CHANGES TO THE FORECAST AS IT SHOWS THIS TREND WELL WITH CHANCE MOUNTAIN POPS FOR EACH AFTERNOON AND EVENING THROUGH THE WEEKEND...THEN DROPPING POPS A CATEGORY FOR THE REMAINDER OF THE PERIOD. SHOULD SEE A LITTLE COOLING FOR THE WEEKEND...RECOVERING AS THE HIGH REBUILDS LATER IN THE NEW WEEK. && .GJT WATCHES/WARNINGS/ADVISORIES... .CO...NONE. .UT...NONE. $$ CJC/EH co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1153 AM EDT THU JUL 22 2004 .UPDATE... UPDATE FOCUS IS WITH THUNDERSTORM POTENTIAL THIS AFTERNOON...IN ADDITION TO CLOUD COVER EARLY. COLD FRONT OVER NORTHERN LOWER WILL PUSH ACROSS THE STATE BY 00Z THIS EVENING. 12Z ETA IS SIMILAR TO 00Z/06Z RUNS KEEPING THE FRONT DRY...FOCUSING PRECIP ACROSS ILLINOIS/INDIANA WHERE MCS IS CURRENTLY TRACKING FROM SOUTHERN IOWA. OPPOSING VIEWPOINT OFFERED BY 00Z 4KM WRF FROM NCAR WHICH WEAKENS THE COMPLEX OVER IOWA/ILLINOIS BY AFTERNOON...AND FIRES STORMS BY 19Z ACROSS THE SAGINAW VALLEY WHICH THEN SPREAD ACROSS THE REST OF SOUTHEAST MICHIGAN THROUGH 01Z. SHOULD HAVE ABUNDANT INSTABILITY WITH DEWPOINTS STILL IN THE LOWER 70S...AND 12Z DTX SOUNDING SUPPORTING HIGHS APPROACHING 90F /UPPER 80S OBSERVED UPSTREAM YESTERDAY/ PROVIDED WE SEE FULL INSOLATION. LOW MORNING STRATUS HAD PERSISTED THROUGH MUCH OF THE MORNING...AND HAS ONLY BEGUN TO MIX OUT OVER THE PAST HOUR OVER CENTRAL LOWER. MUCH OF SOUTHEAST MICHIGAN IS STILL UNDER IFR SKYCOVER...ALTHOUGH VISIBILITIES HAVE COME UP TO MVFR/VFR. 12Z DTX SOUNDING SHOWS LOW-LEVEL MOISTURE PRETTY DEEP...AS SEEN WITH STRATUS MIXING OUT TO A BROKEN CU DECK. UPSTREAM THE GRB SOUNDING SHOWED MUCH DRIER AIR JUST OFF THE SURFACE...WITH DEWPOINT DEPRESSIONS UP TO 20C JUST ABOVE 900MB. NO CU OBSERVED ACROSS SOUTHERN WISCONSIN...WITH MORNING STRATUS JUST DISSIPATING WITH DIURNAL MIXING. ETA/RUC WEAKEN THIS DRIER AIR AS IT TRIES TO MOVE INTO LOWER MICHIGAN...BUT 1000-850MB RH DOES DECREASE ALONG THE COLD FRONT BY 00Z. THIS COULD BE ENOUGH TO LIMIT CONVECTIVE POTENTIAL...AT LEAST ACROSS THE NORTHERN CWA. HOWEVER WITH INSTABILITY AND QUESTION AS TO FRONTAL TIMING...WILL KEEP CHANCE POPS GOING ACROSS THE SOUTHERN CWA. WIND FIELD IS RATHER WEAK...WITH 850MB/500MB WINDS NOT REALLY INCREASING UNTIL BEHIND THE FRONT LATE THIS EVENING. 0-6KM SHEAR IS ALSO ONLY NEAR 20M/S...WITH 0-3KM HELICITIES <50M2/S2 AS WELL. IN ADDITION WITH HIGH FREEZING LEVELS /AROUND 15KFT/ WE SHOULD GET BY WITHOUT SEVERE WEATHER IF WE DO SEE CONVECTION. NO MAJOR CHANGES TO THE GOING FORECAST WITH DRY NORTH/CHANCE SOUTH. EVEN WITH A SLOW START...HIGHS NEAR 90 STILL SEEM POSSIBLE GIVEN BREAKS DEVELOPING IN THE CLOUD COVER...WITH SKIES TRANSITIONING OVER TO PARTLY SUNNY. && BRAVENDER .PREV DISCUSSION...245 AM EDT THU JUL 22 2004 CONVECTIVE CHANCES REMAIN MAIN CONCERN IN THE FIRST 24 HOURS OF THE FORECAST OR SO. WILL LIKELY HAVE TO DEAL WITH SOME INITIAL WORDING ISSUES AS ONGOING ACTIVITY WITH LEFTOVER MVC SLOWLY SPINS DOWN AND MOVES EAST OF AREA. THEREAFTER...MODELS ARE VERY DRY WITH COLD FRONT PASSAGE TODAY...DESPITE ADEQUATE INSTABILITY...AND DECENT DIURNAL TIMING WITH FROPA THIS EVENING. WILL ADJUST FORECAST SOMEWHAT...BUT KEEP THE CHANCE OF SHOWERS/THUNDERSTORMS IN FOREACAST FOR ABOUT THE SOUTHERN 1/2 OF CWA LATE THIS AFTERNOON INTO THE EVENING. AREA IS STIL UNCOMFORTABLY CLOSE TO MCS THAT TRACKS EAST ALONG FRONT AS WAVE PROGRESSES FROM THE PLAINS/MIDWEST INTO THE OHIO VALLEY THU NIGHT INTO EARLY FRIDAY. GFS HAS ITS OBVIOUS FEEDBACK PROBLEMS WITH CONVECTION. STILL...CONSENSUS AMONGST MODELS IS TO TRACK THIS SYSTEM THROUGH OHIO VALLEY JUST SOUTH OF CWA IN THE 06Z-12Z TIMEFRAME. WILL LEAVE DRY FOR NOW...BUT THIS FEATURE MAY NEED TO BE ADJUSTED FOR IN THE AFTERNOON PACKAGE. QUIET WEATHER THEREAFTER...OR AT LEAST THROUGH THE WEEKEND INTO EARLY NEXT WEEK. WILL CHANGE VERY LITTLE...WITH JUST SOME MINOR TWEEKS TO TEMPERATURES. BASICALLY EXPECT HIGHS TO MODERATE SLOWLY BUT STEADILY BACK INTO THE LOWER 80S BY NEXT WEEK...AFTER 70S FRIDAY INTO SUNDAY. NORTHEAST FLOW OFF OF RELATIVELY COOL WATERS OF LAKE HURON WILL EVEN KEEP SOME LAKE SHORE AREAS IN THE 60S. MEANWHILE...LOWS ARE EXPECTED TO BE WELL DOWN INTO THE 50S (WITH SOME 40S MIXED IN OVER A PRETTY WIDE AREA THIS WEEKEND...ESPECIALLY SATURDAY MORNING). THESE LOWS WILL APPROACH RECORD LEVELS BOTH SATURDAY AND SUNDAY MORNING WITH CLEAR/CLEAR CONDITIONS UNDER COOL HIGH PRESSURE THAT SETTLES INTO THE LAKES REGION FROM CANADA. HERE ARE THE CURRENT RECORD LOWS: SAT/24TH SUN/25TH DTW 52 51 FNT 45 48 MBS 45 47 TREND HAS CONTINUED TO DEVELOP IN MOST MODELS TO BRING A SIFNIFICANT DISTURBANCE INTO BASE OF EASTERN TROF...AND HENCE BRING A CHANCE OF UNSETTLED WEATHER TO THE AREA BY EARLY NEXT WEEK. AFTERNOON PACKAGE INCLUDED THIS IDEA...WITH A MENTION OF PRECIPITATION CHANCES IN THE TUESDAY/TUESDAY NIGHT TIMEFRAME. SEE LITTLE REASON TO MESS WITH THIS GIVEN THE FAIR AMOUNT OF SUPPORT THAT REMAINS IN MODEL SOLUTIONS. THIS WILL KEEP TEMPERATURES ON THE MILD SIDE...LOWER 80S THROUGH THE END OF THE FORECAST MID NEXT WEEK. NEXT QUESTION COMES JUST BEYOND THIS FORECAST...AS THERE ALSO EXIST SOME BASIC SUPPORT FROM MODELS OF DROPPING ANOTHER SIFNIFICANT SHORTWAVE OUT OF THE GULF OF ALASKA INTO THE AREA BY THE LAST HALF OF NEXT WEEK. THIS SYSTEM APPEARS TO TAP COOLER AIR AGAIN...MUCH LIKE AIRMASS THAT WILL FILTER THROUGH LOWER MICHIGAN THIS WEEKEND. THIS WOULD SPELL AN EXTENSION OF THE COOLISH/UNSETTLED PATTERN INTO NEXT WEEKEND. TIME WILL TELL ON THIS ONE...WAY TOO FAR OUT TO PIN DOWN JUST YET. && .DTX WATCHES/WARNINGS/ADVISORIES...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 1107 AM EDT THU JUL 22 2004 .DISCUSSION... THE MAIN CONCERN WITH THIS UPDATE IS THE TEMPERATURES AND WINDS FOR THIS AFTERNOON. WATER VAPOR IMAGERY AND RUC/ETA INDICATE A SHORTWAVE OVER LAKE SUPERIOR ROTATING AROUND A LOW OVER HUDSON BAY. ANOTHER SHORTWAVE IS OVER NORTHERN MANITOBA ROTATING AROUND THE SAME LOW. A RIDGE IS OVER BRITISH COLUMBIA. SURFACE ANALYSIS SHOWING A LOW OVER NORTHERN QUEBEC WITH A COLD FRONT EXTENDING THROUGH LOWER MICHIGAN INTO THE CENTRAL PLAINS. MORNING RAOBS AND FORECAST SOUNDINGS INDICATE THAT THE AIR MASS IS NEARLY SATURATED BELOW 850MB...WITH A STRONG INVERSION AT 850MB CAPPING THE SYSTEM. VISIBLE IMAGERY SHOWING LOW CLOUDS OVER MUCH OF THE WESTERN TWO THIRDS OF FORECAST AREA. THE FORECAST SOUNDING SUGGEST DRIER AIR SPREADING INTO THE AREA AT THE LOW LEVEL BY MID AFTERNOON. THEREFORE...EXPECT TO SEE SOME SUN THIS AFTERNOON. COLD AIR ADVECTION WILL ALSO CAUSE THE SURFACE TEMPERATURES TO DECREASE THROUGH THE AFTERNOON. THE VORT MAX WILL MOVE INTO CENTRAL U.P. AND EASTERN LAKE SUPERIOR. THE FORECASTED PRESSURE GRADIENTS WILL KEEP WINDS 10 TO 20 MPH OVER THE FORECAST AREA THIS AFTERNOON. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DODGE CITY KS 504 PM CDT THU JUL 22 2004 .DISCUSSION... SHORT TERM... THE RUC AND THE MESOETA SEEM TO BE HANDLING THE SURFACE FEATURES AND THE PRECIP FAIRLY WELL THIS AFTERNOON SO WILL FOLLOW THEIR FORECAST IN GENERAL. SURFACE TROUGH HAS SLID TO THE EAST OF DDC AS WINDS HAVE TURNED AROUND TO THE NORTHWEST. SHOWERS AND STORMS CONTINUE TO DEVELOP TO THE NORTHWEST OF THE TROUGH ACROSS OUR NORTHERN COUNTIES AND AS FAR SOUTH AS STEVENS COUNTY. STORMS HAVE ALSO DEVELOPED JUST AHEAD OF IT ACROSS THE PANHANDLES. BASED ON THIS GOING POP FORECAST LOOKS GOOD. THE FIRST SURGE OF COOLER AIR REINFORCED BY CLOUDINESS AND CONVECTION OCCURRING NORTH OF IT HAS SUNK JUST INTO NORTHERN KANSAS AS I TYPE. ANOTHER SURGE WAS LOCATED FARTHER NORTH ACROSS SOUTH DAKOTA AND MINNESOTA. BOTTOM LINE, WE SHOULD SEE MORE CONVECTION DEVELOP NW OF THE TROUGH AND AHEAD OF THE COLD FRONT THIS AFTERNOON IN A WEAKLY CAPPED ENVIRONMENT. DEEP LAYER SHEAR IS STILL NOT ALL THAT IMPRESSIVE AND CAPE WILL BE LIMITED DUE TO THE POOR LAPSE RATES ALOFT. SO AM ONLY THINKING OF ISOLATED SEVERE THIS AFTERNOON AND TONIGHT. I DIDN'T CHANGE THE POP FORECAST ALL THAT MUCH FOR TONIGHT. THE FRONT WILL SAG SOUTH BY 00Z INTO OUR AREA AND WILL PUSH THRU THE AREA BY 06Z. WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY IS EXPECTED ALONG AND BEHIND THE FRONT AND THAT MATCHES FAIRLY WELL WITH THE GOING GRIDS WHICH HAD CATEGORICAL POPS BASICALLY AREAWIDE. AVIATION... MAIN CONCERNS WITH THE TAFS AND TWEBS WILL CONTINUE TO BE CONVECTION THIS AFTERNOON AND EVENING. BY EARLY TOMORROW MORNING, WE SHOULD START TO SEE MVFR AND IFR CEILINGS MOVE INTO THE TERMINALS AS THE BOUNDARY LAYER SATURATES NORTH OF THE FRONT. DAYS 2-7... THE LARGE SCALE DIAGNOSTICS SHOWED THE GENERAL CIRCULATION PATTERN OVER THE NORTHERN HEMISPHERE TO BE A HIGH LATITUDE WAVE 2 OR 3 AND A LOWER LATITUDE WAVE 5 OR 6. OVER NORTH AMERICA THE MEAN UPPER RIDGE REMAINS IN PLACE OVER THE WEST COAST WITH A DEEPENING AND STRENGTHENING HUDSONS BAY LOW IN PLACE. AS WAVE AFTER WAVE ROTATES AROUND THIS UPPER LOW FROM NORTHERN CANADA AND THE ARCTIC, THE MEAN UPPER TROUGH IS RETROGRADING SLOWLY WESTWARD INTO THE MISSISSIPPI VALLEY. ALL OF THIS IS IN RESPONSE TO FEEDBACKS FROM A BROAD, NEARLY STATIONARY AREA OF TROPICAL CONVECTION OVER THE WESTERN PACIFIC WHICH HAS COUPLED BOTH HEMISPHERES. FARTHER WEST, A MORE ORGANIZED AREA OF TROPICAL CONVECTION WHICH BEGAN OVER THE SOUTHERN ARABIAN SEA HAS WORKED ITS WAY EASTWARD INTO THE BAY OF BENGAL AND IS NOW CLEARLY IDENTIFIED AS A MODERATE MJO IN THE OLR MEANS AN ANOMALIES. UNTIL THIS FEATURE IMPACTS AND ENHANCES THE BROAD STATIONARY AREA OF CONVECTION IN THE WESTERN PACIFIC NEAR THE END OF THIS FORECAST PERIOD LITTLE CHANGE IS EXPECTED IN THE PATTERN OF A SLOW RETROGRESSION OF THE UPPER TROUGH OVER THE CONUS. IN THE MODELS, ALL ARE IN GOOD AGREEMENT WITH RETROGRADING THE UPPER TROUGH AT LEAST THROUGH THE WEEKEND. AFTER THAT THEY STRUGGLE WITH THE PATTERN. WHILE NOT COMPLETELY CERTAIN, THERE IS A GOOD CHANCE THAT THE SUCCESSIVE SHOTS OF ENERGY DIVING SOUTH ACROSS CANADA INTO THE WESTERN CONUS MAY WELL DRAW THE UPPER TROUGH ALL THE WAY BACK INTO THE WESTERN CONUS. THOUGH NONE OF THE MODELS CURRENTLY FORECAST THIS, AM INCLINED TO BELIEVE THE TROUGH WILL NOT BECOME PROGRESSIVE AS THE MODELS TRY TO DO WITH IT DURING NEXT WEEK. HAVE THUS KEPT TEMPERATURES A BIT COOLER AND MAINTAINED AT LEAST SOME CHANCE FOR PRECIPITATION, ESPECIALLY FOR NEXT WEEKEND. HAVE ALSO RAISE OVERNIGHT LOWS A LITTLE DUE TO INSULATION FROM EXTENSIVE CLOUD COVER THROUGH THE COMING WEEKEND. IN SHORT, THE NEXT 5 DAYS AND BEYOND WILL BE BELOW NORMAL ON TEMPERATURES AND ABOVE NORMAL ON PRECIPITATION. && .PRELIMINARY POINT TEMPS/POPS... DDC 63 70 60 71 / 100 90 30 10 GCK 61 68 59 72 / 90 60 30 - EHA 62 67 59 68 / 80 100 40 20 LBL 63 70 60 69 / 100 100 40 20 HYS 62 69 60 75 / 100 50 20 00 P28 65 74 62 69 / 100 100 40 20 && .DDC WATCHES/WARNINGS/ADVISORIES... KS...NONE. && $$ LACY/JOHNSON ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 200 PM MDT THU JUL 22 2004 .SHORT TERM...(TONIGHT THROUGH SUNDAY) TONIGHT AND FRIDAY...COLD FRONT MOVING THROUGH THE AREA THIS AFTERNOON...AND POST FRONTAL UPSLOPE REGIME WILL BE IN PLACE BY TONIGHT. UPPER LEVEL DYNAMICS WILL HELP OUT WITH PRECIPITATION AS WELL...WITH 500 MB WAVE DIGGING SOUTH ACROSS WESTERN KANSAS AND PERSISTENT UPPER LEVEL DIVERGENCE IN RIGHT REAR QUADRANT OF JET. GFS SUFFERING FROM A CONVECTIVE FEEDBACK QPF BULLSEYE ACROSS THE NORTHEAST CWA TONIGHT...AND ROBS MOISTURE FROM THE WESTERN ZONES. ETA/WRF/RUC LOOK MORE REALISTIC FOR AN UPSLOPE EVENT...AND CATEGORICAL POPS WARRANTED ALL ZONES. NUMEROUS SHOWERS WILL LINGER IN THE WEST ON FRIDAY AS UPSLOPE CONTINUES...TAPERING TO SCATTERED SHOWERS IN THE EAST. TEMPERATURES WILL BE MUCH BELOW NORMAL UNDER AN OVERCAST SKY AND NORTHEAST SURFACE WINDS...COULD EVEN SEE SOME RECORD LOW HIGHS...AND WILL UNDERCUT THE MAV BY ABOUT 5F (CLOSE TO MET AND UKMET GUIDANCE). CHANCE OF SHOWERS WILL GRADUALLY DIMINISH AND COME TO AN END BY LATE FRIDAY NIGHT PER MAV POPS. SATURDAY...SHORTWAVE TROUGH WILL TRACK SOUTHEASTWARD ACROSS THE NORTHERN HIGH PLAINS DURING THE DAY AND CENTRAL HIGH PLAINS SATURDAY NIGHT. MOISTURE/INSTABILITY AXIS WILL BE PUSHED AGAINST THE FRONT RANGE...WHERE THUNDERSTORMS WILL INITIATE. SHEAR PROFILES WILL BE FAVORABLE FOR A FEW SUPERCELLS TO DEVELOP OVER COLORADO SATURDAY AFTERNOON...BUT AS THEY MOVE EASTWARD INTO KANSAS AND NEBRASKA INTENSITY/COVERAGE SHOULD DIMINISH WITH THE LACK OF MOISTURE/LOSS OF DAYTIME HEATING. MET/MAV IN GOOD AGREEMENT FOR HIGHS AND NO PLANS TO DEVIATE. SUNDAY...SHORTWAVE RIDGING WILL BE MOVING THROUGH IN THE NORTHWEST FLOW ALOFT. NONETHELESS...STEEP LAPSE RATES WILL BE IN PLACE AGAIN OVER EASTERN COLORADO. DAYTIME HEATING OVER THE PALMER DIVIDE/CHEYENNE RIDGE SHOULD BE ENOUGH TO INITIATE THUNDERSTORMS. MOISTURE AND INSTABILITY AXIS FURTHER EAST THAN SATURDAY...AKRON TO LA JUNTA...AND STORMS SHOULD MAKE BETTER HEADWAY INTO KANSAS/NEBRASKA DURING THE EVENING BEFORE DIMINISHING WITH LOSS OF DAYTIME HEATING. AGAIN...SHEAR PROFILES FAVORABLE FOR SUPERCELLS...MAINLY OVER COLORADO...BUT DIMINISHING INSTABILITY EASTWARD THROWS INTO DOUBT IF INTENSITY CAN BE SUSTAINED. && .LONG TERM...(MONDAY THROUGH THURSDAY) TROUGH WHICH WILL DIG INTO THE UPPER MISSISSIPPI RIVER VALLEY THIS WEEKEND WILL BE KICKED OUT BY DISTURBANCE EJECTING INTO THE CANADIAN PRAIRIE MID WEEK. FOR THE CENTRAL HIGH PLAINS...NORTHWEST FLOW EARLY IN THE WEEK WILL GRADUALLY TRANSITION TO A ZONAL FLOW BY THE END OF THE WEEK. THUS...EXPECT A SLOW WARMING TREND...AND IN GENERAL WILL BE UNDERCUTTING MEX GUIDANCE. CONVECTION...INSTABILITY AND MOISTURE AXIS WILL BEGIN THE WEEK OVER EASTERN COLORADO...AND MOVE A LITTLE FURTHER EAST EACH DAY IN A PERSISTENT LOW LEVEL UPSLOPE REGIME. CANADIAN DISTURBANCE WILL DRAG A COLD FRONT THROUGH THE HIGH PLAINS ON THURSDAY. THUS...WILL HAVE SLIGHT/CHANCE POPS IN COLORADO IN THE AFTERNOON AND KANSAS/NEBRASKA IN THE EVENING EARLY IN THE PERIOD...WITH INCREASING AFTERNOON AREAL COVERAGE BY MID WEEK TO COINCIDE WITH INSTABILITY AND MOISTURE AXIS MOVEMENT. CHANCE POPS WILL BE LIMITED TO SOUTHWEST ZONES MONDAY NIGHT WHEN LEFT EXIT REGION OF JET AND 700 MB VORT MAX SLIDE ACROSS COLORADO. CHANCE POPS MAY BE WARRANTED FOR THURSDAY...BUT TIMING OF THE FRONT DIFFICULT AT THIS RANGE...SO LEFT SLIGHT CHANCES FOR NOW. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ JDK ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 415 PM EDT THU JUL 22 2004 .DISCUSSION... WITH DRY WEATHER IN STORE...MAIN FCST CONCERNS ARE CLOUDS/TEMPS. WV IMAGERY AND RUC ANALYSIS INDICATED HUDSON BAY VORTEX WITH TROF DOMINATING CNTRL CANADA AND THE N CNTRL CONUS DOWNSTREAM FROM WRN NOAM RDG. MAIN SHRTWV SPOKE EXTENDED FROM NW ONTARIO INTO CNTRL MANITOBA. AT THE SFC...A COLD FRONT STRETCHED FROM NRN QUEBEC TO N LK HURON AND SRN WI LEAVING COLD/DRY ADVECTION OVER THE WRN LAKES WITH NNW FLOW. VIS LOOP INDICATED ABUNDANT CU/SC PERSISTING ACRS THE UPR MI AS H8 TEMPS FALL TOWARD 5-7C BUT CLEARING HAS SPREAD FROM THE WRN LAKE INTO THE KEWEENAW. WHILE CURRENT DEWPOINTS RANGED FROM THE UPPER 40S W TO THE MID 50S S AND E...UPSTREAM DEWPOINTS N OF LK SUPERIOR WERE IN THE UPPER 30S F TO AROUND 40. TONIGHT...ETA LOW LVL RH FCST AND SATELLITE TRENDS SUGGEST CLOUDS WILL FADE THIS EVENING. DIMINISHING WINDS SHOULD SET THE STAGE FOR GOOD RADIATIONAL COOLING OVERNIGHT OVER INLAND PORTIONS OF THE W HLF OF UPR MI. SO...GENERALLY TAPERED INLAND MIN VALUES TOWARD LOWER ETA GUIDANCE NUMBERS. SLIGHTLY STRONGER BNDRY LYR WINDS OF 15-20 KT OVER THE ERN CWA SHOULD KEEP TEMPS FROM FALLING OFF QUITE AS MUCH. FRI...WHILE INCOMING AIRMASS IS VERY DRY...PER 12Z CWPL SNDG...EXPECT THAT ETA/GFS FCST H8 TEMPS LINGERING IN THE 4C-6C RANGE WILL SUPPORT BUILDUP OF SCT-BKN CU INLAND BY MIDDAY. IN ADDITION TO ONSHORE FLOW OVER THE N WEAK GRADIENT WITH RDG BUILDING INTO THE AREA SHOULD ALLOW LK BREEZE TO DEVELOP DURING THE AFTERNOON OFF LK MI. FRI NIGHT...FOLLOWING DECENT MIXING/DRYING WITH DEWPOINTS ALREADY DOWN AOB 40F...AS HI PRES SETTLES OVER THE AREA SETTING UP EXCELLENT RADIATIONAL COOLING CONDITIONS..INLAND MIN READINGS SHOULD FALL TOWARD RECORD OR NEAR RECORD VALUES IN THE UPPER 30S. SOME TRADITIONAL COLD SPOTS OVER INTERIOR CNTRL UPR MI MAY EVEN SEE POSSIBILITY OF FROST...BUT GIVEN VERY LIMITED COVERAGE...MENTION LEFT IN HWO FOR NOW. SAT INTO SUN...SUBSIDENCE AND SFC HIGH PRES WILL CONTINUE TO DOMINATE WITH MID/UPR LVL CONFLUENT FLOW AS POS TILT SFC TROF MOVES SE INTO THE PLAINS. EXPECT SLOW WARMUP WITH AIRMASS MODIFICATION AS FCST H8 TEMPS CLIMB FROM 7C-9C TO 9C-11C. WEAK GRADIENTS WILL ALLOW LK BREEZE DEVELOPMENT. MON-THU...FCST GENERALLY FOLLOWED COMBINATION OF ENS MEAN AND 00Z/06Z GFS. THE 12Z GFS EVOLUTION OF THE H5 LOW FROM THE PLAINS INTO THE LOWER LAKES WAS NOT SUPPORTED BY ENS OUTPUT OR UKMET/ECMWF. SO...DRY FCST MAINTAINED WITH GENERALLY PT TO MOSTLY SUNNY DAYS AND MOSTLY CLEAR NIGHTS WITH E-W SFC RDG CONTINUING TO KEEP DRY WEATHER IN PLACE. UNCERTAINTY BY THU ALSO INCREASES AS UKMET/ECMWF ARE FASTER WITH PATTERN PROGRESSION AS MID LVL TROF MOVES FROM BC TOWARD CNTRL CANADA. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 249 PM CDT THU JUL 22 2004 .DISCUSSION... WIDELY SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING OVER CENTRAL AND SOUTHWEST AREAS OF MN THIS AFTERNOON. ACTIVITY IS IN AN AREA OF DIFFERENTIAL TEMPERATURE ADVECTION...CAPE OF 200-400 J/KG...NEGATIVE LOW LEVEL MOISTURE FLUX DIVERGENCE AS WELL AS AN INVERTED SURFACE TROF. LATEST RUC SHOWS THE AFOREMENTIONED PARAMETERS MOVING SLOWLY INTO FAR EASTERN AND SOUTH CENTRAL AREAS OF MN BY THIS EVENING AND THEN WEAKENING OVERNIGHT. HAVE EXPANDED LOW CHANCE POPS TO COVER ALL OF THE MN FA THIS EVENING AS WELL AS A FEW COUNTIES BORDERING MN IN WEST CENTRAL WI. THE LOW LEVEL FLOW WILL BECOME MORE ANTICYCLONIC ON FRIDAY ALONG WITH DECREASING LAYER HUMIDITY. WILL KEEP A GOOD AMOUNT OF CLOUDS IN THE GRIDS TONIGHT...THEN SHOW THEM DECREASING DURING THE DAY TOMORROW. A STRETCH OF DRY WEATHER EXPECTED THROUGH SUNDAY AS HIGH PRESSURE BUILDS ACROSS THE REGION. HIGHS AND LOWS A LITTLE BELOW SEASONAL NORMALS. USED AN AVERAGE OF THE MET...FWC AND MAV FOR MAX AND MINS. LONGER TERM...SUNDAY NIGHT THROUGH THURSDAY PATTERN SLOWLY PROGRESSIVE NEXT WEEK...WITH LATEST LONG RANGE MODELS... INCLUDING THE GFS MEAN... IN REASONABLE AGREEMENT. WESTERN UPPER RIDGE ALSO WEAKENS SIGNIFICANTLY BY MIDWEEK AS IT TRANSLATES EWD. RIDGE GENERALLY IS INTO THE DAKOTAS BY MONDAY AFTERNOON. THE UK...GFS AND ECMWF ALL TAKE WEAK LEAD SHORT WAVE AND DEEPEN IT A LITTLE BIT AS IT HEADS TOWARD THE EASTERN US LONG WAVE TROF. RIGHT NOW THE MODELS SWING IT ACROSS IOWA MONDAY PLACING CWA IN QUIET WX. THIS WILL NEED TO BE WATCHED IN CASE IT WINDS UP A LITTLE CLOSER TO MN OR WC WISC. TUESDAY AND WEDNESDAY LOOK TO BE QUIET WITH FORECAST AREA BETWEEN AFOREMENTIONED IOWA LOW AND INCOMING STRONG SHORT WAVE EMANATING OUT OF GULF OF ALASKA AND HEADING FOR THE BC COAST THIS WEEKEND. THUS WILL BRING STORMS ACROSS WESTERN COUNTIES WED NIGHT AND ALL OF AREA ON THURSDAY. IN THIS SCENARIO...DEWPOINTS WILL BE BACK INTO THE 60S ON TUESDAY WITH POTENTIAL FOR LOWER 70S BY THURSDAY AFTERNOON... THOUGH NOT ENOUGH CONFIDENCE TO BRING THAT MUCH MOISTURE BACK INTO THE PICTURE. && MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ RAH/TDK mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPRINGFIELD MO 244 PM CDT THU JUL 22 2004 .DISCUSSION... ANOTHER HOT AND HUMID DAY IN PROGRESS ACROSS THE FORECAST AREA. LOOKS LIKE HEAT INDICES WILL TOP OUT NEAR 100 DEGREES. CONSIDERABLE AMOUNT OF CUMULUS HAD DEVELOPED DURING THE AFTERNOON. RUC ANALYSIS AND SOUNDINGS SUGGEST SURFACE BASED CAPES ARE GENERALLY NEAR 1500 J/KG BUT APPROACH 3000 ACROSS CENTRAL AND SOUTH CENTRAL MISSOURI. ALTHOUGH THERE APPEARS TO BE LITTLE IN THE WAY OF A CAP...THERE ARE NO DISCERNIBLE BOUNDARIES TO FOCUS CONVECTION UNTIL YOU GET INTO CENTRAL MISSOURI. THIS BOUNDARY STRETCHED FROM NEAR ST. LOUIS TO NEAR JEFFERSON CITY AND SEDALIA AT 18Z. AREAS NEAR THIS BOUNDARY AND EAST OF SPRINGFIELD APPEAR TO HAVE THE BEST CHANCE OF CONVECTIVE DEVELOPMENT THROUGH THIS EVENING. THE SYNOPTIC COLD FRONT WAS LOCATED FARTHER NORTH AND EXTENDED FROM SOUTHERN WISCONSIN INTO NEBRASKA. THIS FRONT WAS DROPPING SOUTH IN RESPONSE TO A UNSEASONABLY DEEP 500 MB TROUGH ACROSS CENTRAL CANADA. THESE FEATURES WILL BE THE PRIMARY WEATHER MAKES THE NEXT FEW DAYS. AS MENTIONED ABOVE THE OUTFLOW BOUNDARY WILL HAVE TO BE MONITORED FOR CONVECTIVE INITIATION THROUGH THE EARLY EVENING. OTHER STORMS WILL FORM FARTHER NORTH ACROSS NORTHERN KANSAS AND MISSOURI ALONG AND BEHIND THE COLD FRONT. CONVECTION WILL BE SUPPORTED BY DESCENT SYNOPTIC SCALE FORCING FOR MID SUMMER. PERSISTENT REGION OF UPPER LEVEL DIVERGENCE WILL BE MAINTAINED IN THE ENTRANCE REGION OF THE UPPER JET THAT WILL SAG SOUTH WITH TIME. THIS COMBINED WITH INCREASING MASS CONVERGENCE AT 850 MB WILL LIKELY FOCUS STORM DEVELOPMENT FROM NORTH CENTRAL KANSAS INTO NORTHWEST MISSOURI TONIGHT. THIS ACTIVITY WILL SAG SOUTH INTO THE OZARKS REGION LATE TONIGHT OR FRIDAY MORNING. SOME QUESTION AS TO HOW FAR SOUTH THE FRONT WILL MAKE IT ON FRIDAY. THE ETA BRINGS THE FRONT OR LEAST THE EFFECTIVE SURFACE BOUNDARY THROUGH THE FORECAST AREA FRIDAY MORNING WHILE THE GFS DEVELOPS A SURFACE WAVE AND STALLS THE FRONT ACROSS OUR NORTHERN COUNTIES. I WILL LEAN TOWARD THE ETA AS THE GFS APPEARS TO BE SUFFERING FROM SOME CONVECTIVE FEEDBACK. THERE IS SOME QUESTION ON THE EXTENT OF DESTABILIZATION THAT WILL OCCUR FRIDAY AFTERNOON BASED THE FRONTAL POSITION AND EXTENT OF CONVECTIVE DEBRIS CLOUDINESS. IN ANY CASE FRONTAL AND SYNOPTIC SCALE FORCING WILL LIKELY SUPPORT CONVECTIVE DEVELOPMENT THROUGH THE DAY. THE FRONT WILL TEMPORARILY STALL JUST TO OUR SOUTH FRIDAY NIGHT AS IT BECOMES PARALLEL TO THE FLOW ALOFT. INCREASING LOW LEVEL MOISTURE CONVERGENCE AND UPPER DIVERGENCE ALOFT WILL KEEP SHOWERS AND THUNDERSTORMS GOING FRIDAY NIGHT AND INTO SATURDAY MORNING. INCREASING CONCERN FOR FLOODING AS VERY MOIST LOW LEVEL AIRMASS WITH 850 MB DEWPOINTS NEAR 15 DEGREES CELSIUS WILL BE ADVECTED OVER THE SURFACE BOUNDARY AND PRECIPITABLE WATER VALUES ARE PROGGED TO BE IN EXCESS OF 1.75 INCHES. THIS VERY MOIST AIRMASS WILL BE EFFECTIVELY LIFTED IN FAVORABLE SYNOPTIC SCALE PATTERN. I WILL CONSIDER ISSUING A FLOOD POTENTIAL OUTLOOK. HOWEVER THE RISK OF FLOODING WILL BE HIGHLY CONDITIONAL BASED UPON RAINFALL THE NEXT 24 HOURS AND PLACEMENT OF CONVECTIVE COMPLEXES. DEEP LAYERED MOISTURE WILL REMAIN OVER THE AREA SATURDAY AND SATURDAY NIGHT AS THE TROUGH AXIS SAGS SLOWLY SOUTH. I HAVE INCREASED PRECIPITATION CHANCES AND CLOUD COVER THROUGH SATURDAY NIGHT. MUCH COOLER AIR WILL SPREAD INTO THE REGION BEHIND THE FRONT. HIGHS SATURDAY MAY STRUGGLE TO REACH THE LOWER 70S IF PRECIPITATION PERSIST. THE BELOW NORMAL TEMPERATURES WILL LINGER INTO EARLY NEXT WEEK AS AS STRONG CANADIAN HIGH PRESSURE BUILDS SOUTH. FOSTER && .AVIATION... HAZY CONDITIONS WILL PERSIST INTO THE AFTERNOON HOURS. VISIBILITIES WILL GENERALLY BE NEAR 6 MILES BUT LOCALIZED MVFR CONDITIONS NEAR 4 MILES CAN BE EXPECTED. ISOLATED THUNDERSTORMS WILL DEVELOP ACROSS CENTRAL AND SOUTH CENTRAL MISSOURI...BUT CONVECTION IS NOT EXPECTED AT THE SPRINGFIELD OR JOPLIN TERMINALS THROUGH THE AFTERNOON. THE CHANCE OF STORMS WILL INCREASE TONIGHT AND FRIDAY AS A COLD FRONT APPROACHES FROM THE NORTH. FOSTER && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. $$ WFO SGF mo AREA FORECAST DISCUSSION...UPDATED FOR AVIATION SECTION NATIONAL WEATHER SERVICE CLEVELAND OH 545 PM EDT THU JUL 22 2004 .AVIATION(00Z-00Z) CWA VFR ATTM XCP FOR CAK BUT SAT LOOP SHOWS MOST AREAS SCT ACRS THE AREA. BIGGEST PROB FOR THE EVG AND OVERNIGHT IS TSTM DVLPMT. TO OUR WEST...MSC CRNTLY OVR IND/SERN IL. PROPAGATION OF THIS COMPLEX HAS BEEN TO THE SE AND SAT LOOP SHOWS OUTFLOW BNDRYS RACING SE OUT OF THE AREA. COLDEST TOPS ALSO NOW ACRS SRN IND. RUC SHOWS BEST CAPES REMAIN IN THIS AREA WHICH SHOULD KP CORE OF THIS CONVECTION OUT OF OUR AREA. NEXT PROBLEM WILL BE TSTMS ACRS NRN INDIANA AND THOSE WHICH HAVE JUST DEVELOPED ACRS SERN LWR MI IN RESPONSE TO A PREFNTL TROF. RUC ALSO SHOWS AN AXIS OF CAPE EXTENDING NE FROM INDIANA INTO THIS AREA BUT WEEKENS IT THRU THE EVG. BLV TSTMS ACRS NRN INDIANA WILL REACH INTO NWRN OH DURG THE EARLY EVG. ALSO BLV THRU THE EVG TSTMS WL CONT TO DEVELOP ON THE PREFNTL TROF AND WILL LKLY AFFECT MUCH OF THE AREA BEFORE MIDNIGHT OR SO. && .SHORT TERM (TONIGHT-SUNDAY)... SFC FRONT EXTENDING FROM CENTRAL LK HURON THROUGH SRN WI WL MOVE THRU THE AREA OVERNIGHT...LEADING THE WAY FOR A SIGNIFICANT COOLDOWN. EVEN THOUGH IT WILL BE LATE JULY...IT WILL FEEL LIKE EARLY AUTUMN OVER THE WEEKEND. FIRST THINGS FIRST THOUGH. A FORWARD PROPAGATING MCS HAS DEVELOPED OVER IOWA AND ILLINOIS AND IT SHOULD INTENSIFY AS IT MOVES INTO THE EXTREME INSTABILITY OVER INDIANA. AS IT MOVES TOWARD OHIO...IT WL LIKELY TURN RIGHT AS IT FOLLOWS THE CORFIDI VECTORS THIS EVENING. HOWEVER...THE ETA AND GFS WOULD SUGGEST THAT THE SYSTEM WL NOT BE ABLE TO TURN RIGHT IN TIME TO MISS THE WESTERN 1/2 OF THE FORECAST AREA. HAVE KEPT POPS IN THE 30-40 IN THE I-71 CORRIDOR...AND 40-50 FROM TOL-FDY. HAVE OPTED TO KEEP EXTREME NE OH/NW PA DRY WITH LACK OF INSTABILITY THIS AFTN...AND LIKELIHOOD THAT MCS WL MISS THEM. OTHER THAN THE MCS...DO NOT REALLY EXPECT ANY STORMS TO DEVELOP IN ADVANCE OF THE FRONT AS CLD CVR FROM MRNG COMPLEX HAS NOT ALLOWED FOR MUCH DESTABILIZATION OVER EASTERN OHIO/NW PA THIS AFTN. WESTERN OHIO IS SEEING SOME SUNSHINE THIS AFTN...AND THAT AREA WOULD HAVE THE BEST CHANCE FOR STORMS THIS EVENING. IF MCS DOES NOT MAKE THE TURN IN TIME...THERE IS A SEVERE THREAT FOR WESTERN OHIO...BUT THINK THAT SEVERE THREAT IS MINIMAL FOR EASTERN OHIO/NW PA. OTHER THAN THAT...THE PCPN WL BE CONFINED MAINLY TO THE MCS...OR REMNANTS THERE OF. BY 12Z...THE FRONT SHOULD BE JUST SE OF THE FORECAST AREA. HOWEVER...THE FRONT WL BE CLOSE ENOUGH TO WARRANT 30 POPS IN THE MORNING BEFORE THE CANADIAN HIGH BUILDS IN. A SIGNIFICANT CHANGE OF WEATHER IS IN STORE FOR THE GREAT LAKES WITH MUCH DRIER AND COOLER WEATHER FOR THE WEEKEND. 850MB TEMPS DROP TO A VERY AUTUMN LIKE +6C ACROSS THE FORECAST AREA...WITH NE SFC WINDS DEVELOPING FRI AFTN. WITH THE LAKE AROUND 22C...DELTA-T VALUES ARE SUFFICIENT FOR LAKE CLOUDS. WL BE INTERESTING IF ANY LAKE EFFECT RAIN SHOWERS CAN SET UP WITH THE STEEP LOW LVL LAPSE RATES FRI NIGHT/SAT...ALTHOUGH AMT OF DRY AIR WILL BE MAIN INHIBITING FACTOR. WKND SHOULD BE VERY PLEASANT. MIGHT HAVE A CHANCE TO SEE RECORD LOWS AT SOME POINT DURING THE WKND...ESPECIALLY OVER INLAND NW AND N-CENTRAL OHIO. THINK BEST CHANCE WOULD BE SUN MORNING WHEN RIDGE AXIS IS A LITTLE CLOSER TO WESTERN OHIO. ETA 2M TEMPS DROP INTO THE LOW-MID 40S OVER INLAND AREAS. DO NOT THINK TEMPS WL DROP THAT LOW...BUT IT IS POSSIBLE THAT TEMPS AROUND 50 WL OCCUR AWAY FROM THE LAKE. ALTHOUGH THIS PACKAGE WL NOT MENTION RECORD LOWS FOR THE WEEKEND...IT IS A POSSIBILITY. FOR REFERENCE HERE ARE SOME SELECTED RECORD LOWS FOR THE WKND... 7/25 7/26 TOL 50 50 FDY 51 47 CLE 47 46 MFD 52 53 CAK 47 44 YNG 44 49 ERI 49 52 EVEN IF NO RECORDS ARE BROKEN...HIGHS OVER THE WKND WL BE UNSEASONABLY COOL...GENERALLY IN THE LOWER 70S. && .LONG RANGE (SUNDAY THROUGH THURSDAY)... A RELATIVELY COOL PATTERN WL CONTINUE THRU THE PERIOD WITH A TROUGH REMAINING OVER THE EASTERN HALF OF THE COUNTRY...WITH THE UPSTREAM ATLC RIDGE IN PLACE. POLAR FRONT REMAINS THE FOCUS FOR PCPN THRU THE PERIOD...WITH MDLS SHOWING THAT FEATURE REMAINING S OF THE AREA THRU THU. HOWEVER...THE MDLS SHOW SOME TYPE OF AN INVERTED TROUGH OVER THE APPALACHIANS/OH VLY TUE-THU AS THE AREA REMAINS IN DIFFLUENT FLOW ALOFT. WL THEREFORE HAVE TO CONTINUE WITH CHC POPS FOR THE TUE-THU TIME FRAME. COOL AND DRY CANADIAN HIGH PRES SHOULD REMAIN STRONG ENOUGH OVER THE FORECAST AREA ON MONDAY TO KEEP ANY PCPN S OF THE AREA DESPITE THE 12Z GFS SHOWING PCPN MOVING NWD MON MORNING. TEMPS IN THE EXTENDED WL REMAIN BELOW NORMAL...ALTHOUGH THEY MAY WARM TO NEAR NORMAL BY THU WITH 850 MB TEMPS RISING TO AROUND 15C. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE PA...NONE && $$ SHORT TERM...MRD LONG TERM...MRD AVIATION...TK oh