AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TUCSON AZ 915 PM MST SAT AUG 19 2006 .SYNOPSIS...A MORE ACTIVE THUNDERSTORM PATTERN WILL DEVELOP SUNDAY AFTERNOON AND REMAIN IN PLACE THROUGH MUCH OF THE UPCOMING WEEK. WITH A MOIST SOUTHERLY AND SOUTHEASTERLY FLOW ALOFT IN PLACE OVER THE AREA. && .DISCUSSION...INTERESTING SET UP THIS EVENING...OLD OUTFLOW BOUNDARY FROM EARLIER CONVECTION OVER THE WHITE MOUNTAINS HAS MOVED SOUTH AND BECOME QUASI-STATIONARY FROM TUCSON-BENSON-RUCKER CANYON. STRONG COLD POOL IS LOCATED OVER SOUTHERN NEW MEXICO...CENTERED NEAR LORDSBURG...WHERE INTENSE CONVECTION TOOK PLACE SEVERAL HOURS AGO. SOUTH OF THIS COLD POOL WARM TOP CONVECTION HAS DEVELOPED OVER THE NEW MEXICO BOOT AND NORTHERN CHIHUAHUA AND IS BEGINNING TO EXHIBIT HEAVY RAIN SIGNATURE. THIS CONVECTION SEEMS TO HAVE DEVELOPED IN CONCERT WITH SOUTHERN PERIPHERY OF ABOVE MENTION COLD POOL AND INCREASING MOIST MID-LEVEL SOUTHEAST FLOW WITH RETROGRADING SRN PLAINS HIGH. IF ORGANIZED HEAVY RAIN SIGNATURE SYSTEM DOES INDEED FORM...IT WILL LIKELY RIDE UP BOUNDARY OVER COCHISE COUNTY OVERNIGHT...WITH FLASH FLOOD THREAT POSSIBLE. SINCE SYSTEM IS STILL A FEW HOURS FROM COCHISE COUNTY WILL GIVE IT ANOTHER HOUR OR SO BEFORE RAISING POPS SIGNIFICANTLY. ON TO TOMORROW...RUC DEPICTS INCREASING EAST-SOUTHEAST FLOW SURFACE TO 20,000 FEET THROUGH THE DAY...UNDER GOOD UPPER JET DYNAMICS 30-40KT ABOVE 30,000 FEET FROM THE SOUTHWEST. WE HAVE SEEN A GOOD DEAL OF COOLING 650 MB AND ABOVE...SO WITH ADDED MOISTURE WOULD EXPECT THINGS TO BE QUITE UNSTABLE. MID-LEVEL FLOW WILL BECOME DEEP ENOUGH AND STRONG ENOUGH TO CARRY CONVECTION WEST-NORTHWEST FROM HIGHER TERRAIN AS THE DAY PROGRESSES. STRONG MOISTURE BOUNDARY CURRENTLY IN PLACE...THE KTUS 0Z SOUNDING WAS UP TO 1.38 PW AND GOES SAT SHOWS VALUES UNDER AN INCH OVER THE CENTRAL AND WESTERN DESERTS...WHERE DEEPER SOUTHWEST FLOW REMAINS. THIS WOULD INDICATE BEST CHANCES EASTERN PIMA AND EASTWARD...ALTHOUGH WOULD NOT BE SURPRISED TO SEE ACTION MIGRATE INTO THE CENTRAL DESERTS BY EVENING. OF COURSE DEBRIS CLOUDINESS FROM POSSIBLE OVERNIGHT ACTIVITY COULD HOLD ACTION BACK ON SUNDAY. && .AVIATION...TAFS AND TWEBS ADEQUATELY COVER ALL SIGNIFICANT WEATHER AT KTUS. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. && $$ WEATHER.GOV/TUCSON SHOEMAKER az AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 920 AM EDT SAT AUG 19 2006 .DISCUSSION... WELL...IN THE FACE OF 40-50KT OF SHEAR...THE TROPICAL LOW EAST OF KJAX IS MANAGING TO DO EXACTLY WHAT I THOUGHT IT WOULD NOT - NAMELY ...CONTINUE TO GENERATE CONVECTION. LOOKS LIKE A NUMBER OF FACTORS CAME TOGETHER TO COUNTERACT THIS SHEAR: 1) LOW LEVEL CONVG ASCD WITH THE COMPACT BUT WELL DEFINED LLC REMAINS STRONG 2) THE CENTER IS ONLY A LITTLE WEST OF WESTERN WALL OF THE GULF STREAM. 3) THE NOCTURNAL CONVECTIVE MAX. 4) FINALLY...THE SHEAR PROFILE ITSELF - RUC ANLYS SHOWS H25 DIVG HAD RE-STRENGTHENED OVER THE TOP OF THE SYSTEM OVERNIGHT...BETWEEN THE RIDGE TO THE NORTH AND THE TUTT LOW TO THE EAST. IN TURN...THE CONVECTION CONTINUES TO SPEW OUT A THICK CANOPY OF CS/AS DEBRIS SSW-WARD ACROSS A GOOD CHUNK OF OUR CWA. ONCE AGAIN... IT BECOMES THE FCST "PROBLEM DU JOUR" SINCE IT WILL CONTINUE TO AFFECT INSOLATION AND RESULTANT DIURNAL CONVECTION OVER THE CWA. GIVEN THE SHALLOW/SHEARED STATE OF THE SYSTEM...IT IS MOST LIKELY TO FOLLOW A TRACK CLOSE TO THE BAMS...WHICH MEANS A VERY *SLOW* DRIFT WWD. RADAR INDICATES THIS IS THE CASE...WHICH MEANS THE CENTER WILL STAY OVER WATER LONGER...AND IS THUS MORE LIKELY TO TOOT OUT SOME ADDITIONAL PUFFS OF CONVECTION TODAY. ALSO...SHORT RANGE GUIDANCE SUGGESTS THAT THE STRONG FLOW OVER THE TOP OF THE SYSTEM WILL REMAIN LARGELY DIVGT...WHICH MAY PREVENT CONVECTION FROM BEING COMPLETELY STRIPPED LIKE IT WAS FRI AFTN. WHILE THERE IS A CONSIDERABLE AMOUNT OF UNCERTAINTY IS THE LOCAL SHORT RANGE FCST...I PLAN TO INCREASE CLOUDS...SHAVE A DEG OR TWO OFF OF MAXES...AND CUT BACK POPS 10-20% SAVE FOR THE FAR WRN INTR. && .MARINE...FOR THE FLG-COF LEG...SW-SSW WINDS WILL REMAIN AROUND 10KT WITH SEAS 2-3FT. POSN OF THE RIDGE AXIS ACROSS THE SRN HALF CWA WILL KEEP WINDS S-SE THERE WITH SEAS RUNNING A LITTLE EITHER SIDE OF 2FT. && .AVIATION...MAY NEED SOME LATE MORNING AMDS TO CHG TIMING/INTENSITY OF DIURNAL CONVECTION. I THINK THERE'S A GOOD ALL THE COASTAL AERODROMES WILL HAVE A DELAYED ONSET...AND COASTAL SITES MAY MISS OUT ON SHRA/TSRA ALTOGETHER. && .MLB WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...CRISTALDI LONG TERM....SPRATT fl AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PEACHTREE CITY GA 1112 AM EDT SAT AUG 19 2006 .UPDATE... SENDING A QUICK UPDATE TO LOWER POPS FOR THIS AFTERNOON. KEPT VERY SLIGHT CHANCE NEAR NORTHERN BORDER...AS WELL AS IN FAR SOUTHEAST ZONES. LOW SPINNING OFF THE COAST IS ALLOWING CONVECTIVE ACTIVITY TO DEVELOP INLAND...AND LATER TODAY IT MIGHT GET AS FAR WEST AS AFOREMENTIONED ZONES. FOR THE REST OF THE AREA...KFFC 12Z SOUNDING SHOWS MIDLEVEL INVERSION NEAR 700MB. KBHM AND KTLH SHOWING SIMILAR MIDLEVEL STABILITY...SO DO NOT EXPECT CAP TO BREAK. CAVEAT TO THIS WOULD BE IMPULSE MOVING DOWN THROUGH ALABAMA CURRENTLY...IF THERE WAS AN INVERSION PRESENT AT KOHX EARLY THIS MORNING...IT WAS LIFTED OUT BY THE TIME THE SOUNDING WAS TAKEN. WITH THIS AND SLOWLY APPROACHING FRONT...HAVE LEFT SLIGHT CHANCE NEAR NORTHERN BORDER. IN ADDITION...BOTH RUC AND NAM (WRF) ARE INDICATING SOME INSTABILITY UP NORTH...WITH THE LATTER HAVING MORE QPF. HOWEVER... NAM ALSO WAS INDICATING PRECIP THIS MORNING...AND THIS WAS VERIFIED ONLY WITH CLOUD COVER. MADE MINOR ADJUSTMENTS TO SKY GRIDS AND TEMPS BASED ON CURRENT TRENDS...BUT SHOULD MAKE LITTLE DIFFERENCE IN WORDING OF FORECASTS. ZONES WILL BE OUT SHORTLY. && .PREV DISCUSSION... (ISSUED 520 AM EDT SAT AUG 19 2006) SHORT TERM...(TODAY THROUGH MONDAY) PRIMARY FEATURE IN THE SHORT TERM PERIOD IS COLD FRONT WHICH CURRENTLY IS LOCATED FROM GREAT LAKES REGION TO KANSAS CITY. INTENSE MCS WHICH DEVELOP AHEAD OF FRONT FRI EVENING ACROSS MO HAS DISSIPATED. LIKELY SEE ADDITIONAL MCS DEVELOPMENT TONIGHT ACROSS KY/TN WHICH COULD SPILL INTO NRN ZONES LATE TONIGHT. GFS/NAM ALSO INDICATING A POSSIBLE PRE...FRONTAL TROUGH/WAA ZONE TODAY EXTENDING FROM FAR NORTH GA INTO OH VALLEY. THIS WAA ZONE RESULTS IN HIGHER MEAN RH AND 20...30 POPS TODAY ACROSS NORTH GA. NOT SURE ON STRENGTH OR VALIDITY OF THIS FEATURE GIVEN FAIRLY CLEAR SKIES ACROSS INDICATED AREA ATTM. HAVE TRIMMED BACK POPS SOME FOR TODAY. BY TONIGHT...THREAT FOR PRECIP WILL CONTINUE AS PRE...FRONTAL TROUGH SLIDES THROUGH MUCH OF NORTH GA. PATTERN ALSO APPEARS FAVORABLE FOR MCS DEVELOPMENT OVER TN/KY AS MENTIONED EARLIER. FOR SUNDAY AND MONDAY...MODELS HAVE A CHANGE IN PLANS FOR US AS FRONT NOW PROGGED TO HANG UP ACROSS TN/FAR NORTH GA WITH SFC LOW REDEVELOPING OVER MID TO LOWER MS VALLEY. CHANGE APPEARS TO BE DUE TO WEAKER S/W MOVING THROUGH NEW ENGLAND COMPARED WITH PREVIOUS MODEL RUNS. EXPECT SCT CONVECTION MAINLY OVER NORTHERN 1/2 OF CWA SUNDAY AND MORE WIDESPREAD CONVECTION MONDAY AS FRONT SHIFTS EAST INTO CENTRAL TN...WRN AL...SE TX. MAX TEMPS SEEM A LITTLE WARM GIVEN THREAT OF PRECIP...BUT GIVEN MORE ISOLD...SCT COVERAGE AND WAA AHEAD OF FRONT...SHOULDNT BE TOO HARD TO REACH LOWER 90S. LONG TERM...(MONDAY NIGHT THROUGH FRIDAY) FRONT STILL PROGGED TO MOVE SLOWLY...REACHING NORTH GA BY TUES AND SLOWLY SAG SOUTH THROUGH LATE WED. NW FLOW OVER NEW ENGLAND PROGGED TO INTENSIFY SFC ANTICYCLONE WED WHICH SHOULD EVENTUALLY PUSH FRONT SOUTH OF CWA. SIMILAR TO WHAT OCCURRED LATE THIS WEEK ..COULD SEE SFC LOW DEVELOP IN THE GULF STREAM OFF SC COAST LATE NEXT WEEK. GFS HINTS AT THIS AND IN FACT SPREADS MOISTURE AND PRECIP BACK NORTH LATE FRI AND SAT. WEAKNESS IN H5 RIDGE ALSO NOTED OVER FL. TROPICAL DEVELOPMENT STILL NEEDS TO BE WATCHED. 00Z GFS NOT SHOWING ANYTHING IMMINENT BUT 18Z DGEX DOES PROG TROPICAL DISTURBANCE TO MOVE FROM YUCATAN STRAITS NE TOWARDS NRN FL PENINSULA LATE FRI. 00Z GEM AND ECMWF DO NOT SUPPORT THIS HOWEVER. AVIATION... VFR CONDITIONS WILL CONTINUE THROUGH TONIGHT. A SHORT WAVE MOVING OUT OF THE OHIO VALLEY WILL BRING A RISK OF THUNDER TO NORTH GA AFT 18Z. WILL GO WITH VCTS AT THIS TIME. RISK OF THUNDER SHOULD END SHORTLY AFTER SUNSET. DO NOT EXPECT LOW CLOUDS TONIGHT HOWEVER THERE WILL BE SOME LIGHT FOG WITH VSBYS AROUND 5 SM AFT 06Z MAINLY IN THE AHN/FTY/MCN AREAS. WINDS WILL REMAIN EAST...SLOWLY SHIFTING TO THE SOUTHEAST AFT 18Z...HOWEVER AFT 00Z SPEEDS WILL GO NEAR CALM. .PRELIMINARY POINT TEMPS/POPS... ATLANTA 90 72 91 73 / 5 10 30 20 ATHENS 91 70 92 70 / 10 10 30 20 GAINESVILLE 89 72 90 71 / 10 20 30 20 ROME 94 70 95 70 / 10 10 30 20 COLUMBUS 95 75 95 75 / 5 5 20 20 MACON 93 71 94 72 / 5 10 20 20 PEACHTREE CITY 91 67 92 69 / 5 10 20 20 CARTERSVILLE 91 69 92 70 / 10 10 30 20 && && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ TDP ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1033 AM CDT SAT AUG 19 2006 .DISCUSSION... WILL BE UPDATING THE ZONE FORECAST AND GRIDS SHORTLY TO PUT IN SCT SHOWERS AND ISOLD T-STORMS WITH 30 POPS FOR THIS AFTERNOON NORTH OF THE I-72 CORRIDOR. SHOWERS AND A FEW T-STORMS ASSOCIATED WITH A WEAK UPPER LEVEL SHORTWAVE/MCV IN SW IOWA EXPECTED TO CONTINUE MOVING EAST TOWARD WCENT AND CENT IL THIS AFTERNOON. A LOW LEVEL BOUNDARY EVIDENT ON THE RADAR MOSAIC WAS INTERSECTING THE PRECIP IN SOUTHERN IOWA. THE MAIN SYNOPTIC FRONT WAS ANALYZED FROM JUST EAST OF CMI TO STL. HOWEVER...VERY HUMID AIR PERSISTS BEHIND THE FRONT...WITH THE DRIEST AIR JUST APPROACHING FAR NORTHERN IL. ALL OF THIS BODES WELL FOR PRECIP TO KEEP MOVING INTO WCENT IL WITH ENHANCED LOW LEVEL CONVERGENCE. THE 12Z RUC SEEMS TO HAVE A GOOD HANDLE ON THIS AS WELL. FORECAST TEMPS ARE ON THE MARK...ESPECIALLY CONSIDERING THE CLOUDINESS IN THE AREA...AND THE EXPECTED INCREASE IN CLOUD COVER IN SOUTHWEST AREAS FROM WINCHESTER TO SPRINGFIELD WHERE THE SKY IS MAINLY CLEAR AT THIS TIME. && .PREV DISCUSSION... SHORT RANGE MODELS NOT DOING THE BEST WITH ONGOING SCATTERED CONVECTION SOUTH OF I-72 AND EAST OF I-55...THOUGH 06Z RUC CAPTURES QPF FIELDS THE CLOSEST AND USED THIS AND RADAR TRENDS THIS MORNING. AREAS OF DENSE FOG ALSO NOTED NW OF THE IL RIVER. FORECAST CHALLENGE IS DEALING WITH THIS MORNING FOG AND IF DENSE FOG ADVISORY NEEDED...AND THEN LOOKING AT CONVECTION CHANCES THIS WEEKEND...AS CONVECTION CHANCES SUPPRESSED FURTHER SOUTH WITH TIME. SHORT TERM...TODAY THROUGH TUESDAY... 07Z/2 AM SURFACE MAPS SHOWS 1013 MB (WEAK) LOW PRESSURE OVER NE IL NEARW KANKAKEE WITH A FRONTAL BOUNDARY EXTENDING SW ACROSS CENTRAL IL NEAR THE IL RIVER INTO NORTHERN MO NORTH OF I-70 AND TO 1012 MB LOW OVER NORTHCENTRAL OK. MCS AND SHORT WAVE OVER NORTHERN INDIANA AND FAR NE IL AND WEAKENING WITH ITS AREA OF CONVECTION. JUST WIDELY SCATTERED SHOWERS LEFT OVER CENTRAL/SE IL EAST OF I-55 AND SOUTH OF I-72. AN OUTFLOW BOUNDARY FROM MCS WAS OVER SE IL NEAR I-70. ANOTHER MCS WAS OVER THE CENTRAL PLAINS OF NW MO AND EASTERN KS. TEMPS WERE IN THE LOWER 70S AND CLOSE TO MATCHING DEWPOINTS AROUND 70F. DENSE FOG WITH VSBY 1/4 TO 1/2 MILE AT GALESBURG...MACOMB AND PONTIAC. ALOFT A 595 DM 500 MB SUBTROPICAL HIGH WAS OVER AR. WEAK LOW PRESSURE AND SHORT WAVE IN NE IL MOVES EAST ACROSS THE SOUTHERN GREAT LAKES TODAY WHILE LINGERING A FRONTAL BOUNDARY CLOSE TO I-70. BEST CHANCES OF CONVECTION TODAY TO BE OVER SE IL WITH LESS CHANCE NORTHERN AREAS. BUT THESE AREAS HAVE WIDESPREAD AREAS OF FOG FROM THE IL RIVER NW AND DENSE AT GALESBURG...MACOMB AND PONTIAC. LACON WAS DOWN TO 3/4 MILE AND NOW AT 1.25 MILES WHILE PEORIA WAS 4 MILES. WILL DECIDE BY 4 AM IF DENSE FOG ADVISORY NEEDED...BUT RIGHT NOW LEANING ON NOT ISSUING ONE SINCE NOT WIDESPREAD ENOUGH YET. IF I DID GO WITH ONE IT WOULD BE FAR NW COUNTIES BY GALESBURG. WILL BE DROPPING THE FLOOD WATCH OVER EASTCENTRAL IL AT 4 AM FORECAST PACKAGE SINCE CONVECTION CHANCES HAVE LOWERED BELOW LIKELY CHANCES. SPC HAS SLIGHT RISK JUST SOUTH OF FLORA AND LAWRENCEVILLE TODAY. FOLLOWED COOLER HIGHS TODAY WITH MORE CLOUDS AND LIGHT NORTH FLOW WITH 80 TO 85F MOST AREAS EXCEPT SOME UPPER 80S FAR SE IL AT LAWRENCEVILLE. CONTINUED RISK OF CONVECTION THIS EVENING...THEN DRY AFTER MIDNIGHT. ADDED SOME FOG TO SE IL OVERNIGHT WHERE WINDS ARE LIGHT AND AIR MASS MORE MOIST AND FOG MAY BE NEEDED OVER CENTRAL IL TOO IF NORTH WINDS LIGHT ENOUGH. ANOTHER SURFACE LOW MOVING ALONG FRONTAL BOUNDARY NEAR THE OHIO RIVER SUNDAY BRINGS A CHANCE OF CONVECTION TO AREAS SOUTH OF I-72 AND COULD LINGER A RISK IN SE IL INTO SUNDAY EVENING. HIGH PRESSURE OVER THE NORTHERN PLAINS SETTLES INTO THE MIDWEST MON AND TUE BRINGING DRY WEATHER WITH CONVECTION CHANCES SOUTH OF ILX CWFA. LONG TERM...WEDNESDAY THROUGH SATURDAY... BUMPED UP HIGHS A FEW DEGREES DURING MID AND LATE WEEK TO MESH UP BETTER WITH SURROUNDING OFFICES. NOT GOING QUITE AS WARM AS MEX HIGHS IN THE UPPER 80S. ECMWF HAS BEEN MORE CONSISTENT OF THE MEDIUM/EXTENDED MODELS WHICH CONTINUES TO SHOW AN UPPER LEVEL TROUGH IN THE EASTERN U.S. AND AN UPPER LEVEL RIDGE IN THE WESTERN U.S. DURING MID WEEK. A STRONGER WAVE MOVES INTO THE MIDWEST FRI/SAT AND COULD BRING A RISK OF CONVECTION THEN. && ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MILLER/HUETTL il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE INDIANAPOLIS IN 650 AM EDT SAT AUG 19 2006 .AVIATION...DISCUSSION FOR 12Z TAFS FORECAST ISSUES FOR THIS SET WILL BE TO WHAT EXTENT THE LOW CIGS/VIS WILL MAKE IT INTO CENTRAL INDIANA. KLAF CIGS ARE ALREADY BLO 1000 BUT THE REMAINDER OF THE SITES HAVE VFR CIGS BUT EITHER IFR OR MVFR VIS. RUC SOUNDINGS SHOW LOW LEVEL INVERSION LIFTING BY 10Z. HOWEVER UPSTREAM OBSERVATIONS SHOW A WIDE AREA OF BLO 1000 CIGS AND BLO 2SM VIS. THEREFORE AM SKEPTICAL THAT THE MODELS HAVE ANY SORT OF A HANDLE ON THE CURRENT SITUATION. WILL GO WITH A BLEND OF PERSISTENCE AND CLOSELY MONITOR UPSTREAM OBS FOR THE 12Z TAF SET. NEXT ISSUE WILL BE WIND SHIFT WITH FROPA. MODELS HAVE BEEN SLOWING THE COLD FRONT OVER THE LAST SEVERAL RUNS. AT THIS TIME IT LOOKS LIKE FROPA WILL BE AT KLAF AROUND 16Z-18Z KIND-KHUF 18Z-20Z AND KBMG 19Z-21Z. DRY AIR LAGS WELL BEHIND THE FRONT AND WILL NOT MAKE IT INTO THE KLAF AREA UNTIL SUNDAY. THAT SAID IFR/MVFR CONDITIONS ARE POSSIBLE AGAIN TONIGHT AFTER 02Z. && .PREV DISCUSSION...FOCUS ON CLDS/TEMPS AND PRECIP CHCS NEXT FEW DAYS. MODEL HANDLING OF THE LAST 24 HOURS WX AND TEMPS HAS BEEN DISMAL. AS OF THIS AM...NONE OF THE MODELS HAD AN ACCEPTABLE HANDLE ON THE NATURE OF THE ONGOING PRECIP. I WILL LEAN TOWARD A COOLER MAV/NWS FCST TODAY BASED UPON FRI MAX TEMPS AND MOS WARM BIAS. DIFFUSE SFC FRONT APPEARS TO BE LOCATED FROM LOWER MI INTO IL AND NORTHERN MO. A WEAK WAVE ALSO APPEARS TO BE LOCATED ON THE FRONT NEAR CHI. THIS IS A BIT SLOWER THAN THE MODELS HAD FCST. ALOFT...AT 850MB EVENING UPPER AIR SHOWED THE MAIN 850MB FRONT FROM KS INTO SE WI WITH A SECOND BOUNDARY ACROSS THE DAKOTAS/MN. ALOFT...ONE WAVE WAS LOCATED ACROSS IL/IN/MI WHILE ANOTHER...STRONGER WAVE WAS TRAVERSING THE WESTERLIES ACROSS NORTHERN MN. YET MORE ENERGY SET TO IMPACT THE REGION WAS LOCATED ACROSS THE CENTRAL ROCKIES. FOR TODAY...EXPECT SCT TSRA TO MOVE ACROSS THE CWA THIS MORNING. BY AFTERNOON, THE SFC/850MB FRONT SHOULD BE MAKING SOME PROGRESS ACROSS THE CWA. 850MB WINDS SHOULD BECOME NW AND LATEST PROFILERS DO SHOW THIS OCCURRING ACROSS IL/WI. NW WINDS FROM SFC-850MB SHOULD LOWER THE PM RAIN THREAT ACROSS THE NW HALF OF THE CWA. AS WAS THE CASE YESTERDAY...THERE SHOULD BE ABUNDANT CLD COVER TODAY BOTH AHEAD OF AND IN WAKE OF THE SFC BOUNDARY. I FAVOR GOING COOLER THAN ALL MOS WITH THIS IN MIND. TONIGHT...ASIDE FROM LOW RAIN CHCS ACROSS THE SE PARTS OF THE CWA NEAR THE FRONT SAGGING SE INTO OH/KY...THE NIGHT COULD END UP BEING DRY. REMNANT MOISTURE COULD ALSO LEAD TO FOG FORMATION ESPECIALLY SOUTH OF I-70. FCST LOWS REFLECT A BLEND OF MOS AND I WILL NOT CHANGE. SUN...BOTH THE ETA AND GFS ARE NOW FCSTNG ANOTHER WAVE TO DEVELOP ALONG THE 850MB BOUNDARY ACROSS MO LATE SAT NIGHT WITH ASSOCIATED PRECIP MOVING INTO SOUTHERN IL AND SOUTHERN IN ON SUNDAY. BASED ON THE UPPER FLOW I WILL LIMIT RAIN CHCS TO AREAS SOUTH OF A HUF TO BAK LINE BOTH SUNDAY AND SUN NIGHT. I ALSO LIKE THE COOLER MAV GUIDANCE BOTH SUN AND MON GIVEN EXPECTED NE SFC FLOW AND THE POTENTIAL FOR MORE CLD COVER. ECMWF AND GFS ARE ALSO SHOWING THAT THE SFC/850MB FRONT MAY LINGER NEAR THE OH/IN BORDER THROUGH TUES AS ANOTHER WEAK WAVE MOVES JUST SOUTH OF THE STATE. FOR NOW I WILL LIMIT RAIN CHCS TO SUN NIGHT GIVEN RECENT CHANGES AND SKETCHY MODEL PERFORMANCE. TUES AND BEYOND...NO CHANGES WILL BE MADE TO THE GOING FCST. ECMWF WHICH HAS BEEN CONSISTENT OF LATE STILL SHOWS A EASTERN U.S. TROUGH AND WESTERN RIDGE INTO WEDS-THURS BEFORE A STRONGER WAVE MOVES INTO THE MIDWEST FRI. THE GFS IS NOW BUILDING THE RIDGE AND KEEPING TEMPS WARMER WITH DRY CONDS THROUGH THE END OF THE WEEK. THE GOING FCST REFLECTS THE MORE CONSISTENT ECMWF FCST. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. $$ PUBLIC...CO AVIATION...SALLY in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TOPEKA KS 240 PM CDT SAT AUG 19 2006 .DISCUSSION... TONIGHT AND SUNDAY... MCV APPCHG WRN PTN OF CWA THIS AFTN HAS ATTENDANT SHOWERS. NONE OF MODELS HANDLING THIS WELL...HOWEVER, RUC HAS TREND CORRECT IF SOMEWHAT FAST. BECAUSE OF THIS, AND GIVEN ONGOING PCPN UPSTREAM, HAVE DECIDED TO INCLUDE SOME LOWER END POPS AT LEAST THIS EVENING OVER ALL THE CWA. IF TREND OF RUC CONTINUES, THIS MCV SHOULD MOVE EAST OF AREA BY LATE EVENING AND ONLY LINGERING CHANCE WILL BE AS EARLIER DEPICTED ALONG SRN CWA CLOSER TO BAROCLINIC ZONE. APPEARS THIS ZONE WILL WEAKEN WITH TIME IF MODELS ARE CORRECT...AND CHCS FOR PCPN END BY MRNG. STILL HAVE A CONCERN FOR LOTS OF HIGH CLOUDS OVER THE AREA IN SUBTROPICAL MOISTURE PLUME. THE TRAJECTORY FOR THIS PLUME APPEARS FAVORABLE FOR THE HIGH CLOUDS INTO SUNDAY. THUS, CONDITIONS FOR FOG TONIGHT MAY BE A FUNCTION OF HOW MUCH HIGH CLOUDINESS FORMS/PERSISTS OVER THE AREA. OTHER FCST CONDITIONS APPEAR IDEAL FOR SOME DENSE FOG WITH RECENT RAINS OCCURRING AND LIGHT WINDS OVERNIGHT. THE BNDRY LYR DOES APPEAR RATHER MOIST INITIALLY AND WHETHER THIS CAN BE MODIFIED DOWN A BIT OVRNGT PER FCST TO IMPROVE FOG CHANCES REMAINS TO BE SEEN. IN ANY CASE, WON'T TOUCH CURRENT GRID DEPICTION OF FOG FCST MAINLY ALONG/NORTH OF THE TURNPIKE. WITH AFOREMENTIONED CONCERNS INTO TMRW, WILL SHOW LITTLE CHANGE TO ONGOING FORECAST. EVEN THOUGH BAROCLINIC ZONE MAY BE WEAKENING, IT IS STILL CLOSE ENOUGH TO BE OF CONCERN FOR CLOUDS AND PSBL LIGHT PCPN SRN HALF OF CWA. FOR NOW, WILL MAINTAIN CURRENT DRY FCST. TEMPS ONLY SLGTLY ADJUSTED. SUNDAY NIGHT THROUGH TUESDAY... THE EARLY WEEK PERIODS LOOK BENIGN AS HEIGHTS RISE TO THE WEST BEHIND A SYSTEM MOVING THROUGH EASTERN CANADA. HIGH PRESSURE WILL DOMINATE THE LOW LEVELS WITH VERY LIGHT WINDS. MAIN CONCERN FOR HAZARDOUS CONDITIONS IS FOG. MODELS ARE CONSISTENT WITH HIGH LEVEL CLOUDS STREAMING OVERHEAD SUNDAY NIGHT AND INTO MONDAY...POSSIBLY ENHANCED BY THE JET MAX TO THE EAST-NORTHEAST...AND WITH ANOTHER DAY OF SURFACE DRYING...EXPECT FOG TO BE ONLY PATCHY AT THE MOST AT THIS TIME. SOME DIFFERENCES EXIST ON THE DEPTH...STRENGTH...AND PERSISTENCE OF FRONTAL INVERSION...BUT A SLOW WARMING TREND IS STILL EXPECTED AND ONLY MINOR CHANGES WERE MADE TO THE PREVIOUS TEMPERATURE FORECASTS. TUESDAY NIGHT THROUGH SATURDAY... THERE IS GOOD AGREEMENT IN THE MEDIUM RANGE MODELS OVER THE PAST FEW RUNS AND RECENT DAY 5 SKILL SCORES HAVE BEEN RELATIVELY HIGH. UPPER RIDGING OVER THE ROCKIES TO BE BROKEN DOWN BY A COUPLE OF SHORTWAVE TROFS...ONE THAT WILL STAY TO THE NORTH THURSDAY AND A LONGER WAVELENGTH TROF COMES IN BEHIND LATE FRIDAY. THIS SECOND WAVE WILL LIKELY BRING A COLD FRONT INTO THE PLAINS AND PROVIDE SOME CHANCE FOR THUNDERSTORMS FOR FRIDAY NIGHT AND SATURDAY. BEFORE THEN...A RATHER NONDESCRIPT PATTERN SHOULD KEEP SIGNIFICANT WEATHER IN CHECK WITH TEMPERATURES NEAR TO SOMEWHAT ABOVE NORMAL. && .TOP WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 1030 AM EDT SAT AUG 19 2006 .MORNING UPDATE... TWO REASONS FOR MORNING UPDATE...FIRST TO REMOVE ALL MORNING WORDING FROM THE FORECAST. SECOND IS TO DEAL WITH TWEAKS TO THE FORECAST NEEDED ON BOTH TEMPS AND POPS. CURRENT RADAR TRENDS ALONG WITH RUC MODEL DATA SHOWING BEST CHANCES FOR PRECIP STILL LOOK TO BE NORTH OF THE OHIO RIVER EARLY THIS AFTERNOON...THEN MORE SO IN OUR EASTERN ZONES ACROSS THE BLUEGRASS REGION SOUTHWARDS INTO THE LAKE CUMBERLAND REGION LATER THIS AFTERNOON. HAVE SLIGHTLY RAISED POPS IN THE LIKELY CATEGORY IN EACH OF THOSE REGIONS. CLOUD COVER HAD KEPT POPS SLIGHTLY UNDER FORECASTED TEMPS IN THE HOURLY GIRDS THROUGH 10AM ACROSS MUCH OF THE NORTHERN AND WESTERN PORTIONS OF THE FORECAST AREA...HAVE LOWERED HIGHS JUST A DEGREE OR TWO WITH PRECIP AND SIGNIFICANT CLOUD COVER THAT SHOULD REMAIN AT LEAST THROUGH THE EARLY AFTERNOON HOURS. FORECAST SOUNDINGS SHOW PWATS WELL ABOVE 2 INCHES...AND 16+K FT FRZ LVLS...HIGH EFFICIENT PRECIP WILL BE LIKELY IN STRONGER STORMS...HAVE MENTIONED HEAVY RAINFALL IN ZONES AND WILL CONTINUE THIS THEME IN HWO. SEVERE THREAT LOOKS LIMITED ACROSS THE NORTHERN ZONES DUE TO MORE CLOUD COVER DAMPENING THE HEATING/INSTABILITY...SOUTHERN AREAS MAY SEE AN ISOLATED DOWNBURST WITHIN ANY STRONG STORMS. --SCHOTT PREVIOUS DISCUSSION SENT AT 240 AM EDT SHORT TERM (TODAY-TONIGHT)... CONVECTIVE COMPLEX ONGOING OVER CNTRL/SRN PARTS OF IL...MOVING INTO WRN IN AS OF 630Z. THIS PCPN IS BEING DRIVEN BY SMALL SCALE SHORT WAVE TRANSLATING EASTBOUND ALONG NRN PERIPHERY OF STRONG UPPER RIDGE CENTERED OVER SRN STATES. IN CONJUNCTION WITH THIS...A FRONTAL BOUNDARY IS LOCATED ROUGHLY FROM THE GREAT LAKES BACK INTO THE CNTRL HIGH PLAINS. HAVE HEAVILY WEIGHTED THIS FCST TOWARD THE 21Z/18 SREF ENS MEAN... WHICH PICKED UP ONGOING PCPN REASONABLY WELL. BASED ON CURRENT TRAJECTORY OF CONVECTION AND SREF SOLN...FEEL THAT BEST CHANCES THROUGH 12Z WILL BE N OF THE LMK CWA...THOUGH WILL KEEP SOME 30/40 POPS IN OUR NRN ZONES TO ACCOUNT FOR ACTIVITY THAT MAY DEVELOP SOUTHWARD WITHIN VERY MOIST AIRMASS (0Z OHX/ILX SOUNDING PWS ABOUT 150% OF NORMAL...OHX K-INDEX=38 WHICH IS QUITE HIGH). THERE MAY BE A LULL IN PRECIP COVERAGE TOWARD MID/LATE MORNING...WITH A SCT-BKN MID-DECK OF CLOUDS REMAINING. INTO THE AFTN/EARLY EVE...SREF DATA SHOWS PRECIP INCREASING CONSIDERABLY AS SFC FRONT PUSHES NEAR TO THE CWA AND AIRMASS DESTABILIZES. LOCALLY THERE MAY BE TWO MAXIMA IN PRECIP COVERAGE DURING THIS PERIOD...ONE FROM THE BLUEGRASS NEWD CLOSER TO BETTER PROJECTED LOW LEVEL MASS CONVERGENCE...AND ANOTHER OVER SRN/WRN KY ALONG OUTFLOW BOUNDARIES FROM ONGOING CONVECTION AND WHERE BETTER INSTABILITY WILL LIKELY BE. WILL INCREASE POPS TO 50/60%...HIGHEST IN THE BLUEGRASS CONSISTENT WITH SREF DATA. A THREAT FOR STRONG TO SEVERE STORMS EXISTS...WET MICROBURST INDEX/CRAVEN SIG SVR PARAMETERS HIGHLIGHT WRN/SRN SECTIONS OF THE DISTRICT BETWEEN 18-00Z TODAY FOR SEVERE POTENTIAL. WHILE HIGH WINDS AND FREQ LIGHTNING ARE THREATS...WITH PWS SO MUCH ABOVE NORMAL AND FRZ LEVELS ABOVE 16KFT THE PRECIP EFFICIENCIES WILL BE ENHANCED SO WE WILL HAVE TO WATCH FOR LOCALLY HEAVY RAIN/FLOODING. SREF INDICATES THAT TSRA COVERAGE OVER THE CWA WILL DIMINISH AFTER 3-6Z TONIGHT...AS SFC FRONT IS FCST TO SLIDE JUST S/E OF THE CWA. WILL STILL CONTINUE 20-30 POPS PAST MIDNIGHT WITH HIGH K-INDICES REMAINING IN THE VICINITY. ANOTHER ISSUE THIS MORNING HAS BEEN FOG. WITH AT LEAST PARTIALLY CLR SKIES OVER MUCH OF THE CWA...VSBYS HAVE DROPPED INTO THE MVFR RANGE (3-5SM)...WITH LOCALIZED REDUCTIONS BELOW 1/2SM PRIMARILY S/E OF A BWG-LEX LINE WHERE SCT TSRA OCCURRED FRIDAY AFTERNOON. FEEL THAT MAIN FOG THREAT THROUGH 12Z WILL BE IN THESE AREAS...AND HAVE ISSUED AN SPS...HOWEVER IF FOG BECOMES MORE WIDESPREAD THEN AN ADVISORY MAY BE WARRANTED. MOS DATA INDICATING THAT HAZE WILL CONTINUE THROUGHOUT MUCH OF TODAY SIMILAR TO YESTERDAY. WITH PRESUMPTION OF RAINFALL TODAY OVER MUCH OF THE CWA...HAVE ADDED PATCHY FOG LATE TONIGHT AS LOW LEVEL WINDS WILL BECOME LIGHT WITH TROF AXIS IN THE VICINITY. REGARDING TEMPS...I SUSPECT THAT MAX READINGS TODAY ACROSS THE SRN IND/LOU/LEX AREAS WILL BE SLIGHTLY COOLER THAN YESTERDAY WITH ENHANCED CLOUD COVER EXPECTED...HOWEVER ACROSS SRN KY WHERE MORE SUN IS LIKELY HAVE GONE WITH MORE OR LESS A PERSISTENCE FCST. HEAT INDEX VALUES DOWNSTATE MAY APPROACH 100 THIS AFTN. CS LONG TERM (SUNDAY-FRIDAY)... SUNDAY THROUGH MONDAY NIGHT... THIS PERIOD APPEARS TO BE THE MOST CHALLENGING IN THAT THE NUMERICAL MODELS HAVE STARTED A TREND IN SLOWING DOWN THE SFC FRONTAL BOUNDARY AS PRESSES SOUTH THROUGH THE REGION. IN THE UPPER LEVELS...PATTERN CHANGE WILL GET UNDERWAY AT THE BEGINNING OF THE PD AS UPPER LEVEL RIDGE RETROGRADES WESTWARD AND A BAGGY MEAN TROF TAKES SHAPE OVER THE EASTERN U.S. THE TREND IN THE GFS NOW IS CAPTURING A DECENT MID LEVEL WAVE COMING EAST ALONG THE PERIPHERY OF THE DEPARTING RIDGE. THIS FEATURE ALONG WITH THE SLOW MOVING FRONT SUGGESTS THAT PRECIPITATION WILL CONTINUE SUNDAY NIGHT AND THROUGH THE DAY ON MONDAY. FOR SUNDAY...WITH FRONT IN THE AREA...WE EXPECT GENERALLY CLOUDY SKIES WITH SHOWERS AND STORMS COMING IN DURING THE AFTERNOON AHEAD OF ABOVE MENTIONED WAVE. BASED ON THE CURRENT MODEL TRENDS...HAVE INCREASED KEPT POPS IN THE FCST SUNDAY NIGHT AND THROUGH MONDAY AS THIS FEATURE MOVES THROUGH. RIGHT NOW PLAN ON KEEPING POPS IN THE LOW CHANCE CATEGORY AND POSSIBLY UPPING THEM LATER ON DEPENDING ON FUTURE MODEL RUNS. TEMPERATURES WILL BE MODULATED BY CLOUDS AND PRECIP. HOWEVER GENERAL CONSENSUS OF THE MAV AND MET SUGGEST HIGHS IN THE LOWER 80S ACROSS SOUTHERN INDIANA AND MID TO UPPER 80S ACROSS KY. OVERNIGHT LOWS WILL BE MILD WITH LOWS IN THE UPPER 60S TO AROUND 70. HIGHS MAY BE A BIT COOLER ON MONDAY IF GFS SOLUTION VERIFIES AND WE GET A DECENT RAIN. FOR NOW WILL TREND TEMPS CLOSER TO THE GFS ENSEMBLE MEANS. TUESDAY THROUGH FRIDAY... NOT MUCH CHANGE FROM THE PREVIOUS FCST IS EXPECTED IN THE PERIOD. MAJORITY OF THE EXTENDED MODEL DATA CONTINUE TO SUPPORT THE SOUTHERN U.S. RIDGE RETROGRADING WESTWARD LEAVING MORE OF A BAGGY TROF ACROSS THE EASTERN UNITED STATES. THE OHIO VALLEY WILL REMAIN GENERALLY IN NORTHWEST FLOW ALOFT THROUGH THE PERIOD. WITH THE STORM TRACK WELL NORTH OF OUR AREA...GENERALLY DRY WEATHER IS EXPECTED THROUGH THE PD. 00Z GFS SOLUTION SHOWS A BIT OF HEIGHT RISES BY THE END OF THE PD AS TROFFING REDEVELOPS IN THE PACIFIC NORTHWEST AND THEN FURTHER DEVELOPS INTO A HEALTHY MID LEVEL TROF OVER THE NORTHERN PLAINS BY LATE FRIDAY. OPERATIONAL MOS GUIDANCE SHOWS TEMPERATURES MODERATING THROUGH THE PERIOD WITH HIGHS IN THE MID TO UPPER 80S WARMING TO NEAR 90 BY FRIDAY...WITH OVERNIGHT LOWS IN THE UPPER 60S TO AROUND 70. FOR NOW...WILL NOT MAKE WHOLESALE CHANGES THROUGH THIS PERIOD...BUT WILL ADJUST TEMPERATURES CLOSER TO THE ENSEMBLE MEANS. -MJ && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 149 PM EDT SAT AUG 19 2006 .AVIATION... SURFACE LOW EXTENDS FROM SOUTHERN LAKE HURON TO WESTERN LAKE ERIE...WITH VIS SATELLITE/METARS SHOWING WIDESPREAD IFR CONDITIONS ACROSS MUCH OF SOUTHERN LOWER MICHIGAN. FNT IS ON THE FRINGE AND MBS IS PRETTY MUCH OUT OF THE LOW CIGS...BUT VISIBILITIES CONTINUE TO HOVER AROUND 1-2SM IN THE SOUTHERN CWA/3-5SM IN THE NORTHERN CWA. REGIONAL RADAR SHOWS LIGHT DRIZZLE NEAR THE SURFACE LOW...WITH MORE CONVECTIVE LOOKING SHOWERS STARTING TO DEVELOP ACROSS CENTRAL LOWER. STRONGEST REFLECTIVITIES ARE FARTHER NORTHWEST...NEAR THE COMPACT UPPER SHORTWAVE/STRONG JET AXIS...WHERE MID-LEVEL LAPSE RATES ARE STEEPER AND CLOUDS HAVE BEEN THINNER THROUGH THE DAY...ALLOWING FOR BETTER INSOLATION. THE BETTER DYNAMICS/INSTABILITY ACROSS NORTHERN LOWER WILL JUST BRUSH THE NORTHERN CWA. BASED ON LINEAR EXTRAPOLATION FOR TIMING...ADDED A TEMPO FOR TSRA MBS FROM 22-24Z. OTHERWISE WILL PLAY DTW/DET MORE PESSIMISTIC...HOLDING ONTO MVFR CLOUDS INTO THE EVENING. AS THE SURFACE LOW MOVES INTO SOUTHEAST ONTARIO...NORTHERLY FLOW PICKS UP OVERNIGHT WHICH SHOULD HELP TO SCOUR OUT SOME OF THE LOW-LEVEL MOISTURE. HOWEVER NAM/GFS SOUNDINGS SHOW ALL TAF SITES REMAINING SOCKED IN. BROUGHT IN A BRIEF PERIOD OF VFR THIS EVENING...THEN DROPPED CIGS BACK DOWN TO MVFR/IFR AROUND SUNRISE. THE BETTER MIXING WITH THE INCREASING GRADIENT SHOULD LIMIT FOG POTENTIAL DESPITE THE MOIST BOUNDARY LAYER FROM THE RAIN TODAY...LEADING TO MORE OF A LOW STRATUS CONCERN. && .PREV DISCUSSION...ISSUED 1132 AM EDT SAT AUG 19 2006 UPDATE... BROAD SURFACE LOW OVER SOUTHERN LOWER MICHIGAN WILL MOVE INTO ONTARIO/LAKE ERIE THIS AFTERNOON. WIDESPREAD SHOWERS IN THE DEEP WARM/MOIST ADVECTION AHEAD OF THIS SYSTEM ARE JUST EXITING THE EASTERN CWA...WITH REGIONAL RADARS/METARS SHOWING LIGHT SHOWERS/DRIZZLE LINGERING BACK TO THE WEST. 14Z TAMDAR ASCENT SOUNDINGS TO THE WEST OUT OF DTW SHOW THE DEEP MOISTURE ALREADY STRIPPING AWAY...BUT WITH THE COLUMN 700MB AND BELOW REMAINING SATURATED. 12Z RUC/NAM HAVE A DECENT HANDLE ON THE SURFACE LOW POSITION...AND BOTH SHOW A TROUGH LINGERING BACK ACROSS SOUTHEAST MICHIGAN INTO THIS EVENING...AHEAD OF THE STRONGER NORTHERN STREAM SYSTEM OVER THE NORTHERN GREAT LAKES. GIVEN THE ABUNDANT LOW-LEVEL MOISTURE THAT IS EXPECTED TO PERSIST THROUGH MUCH OF THE DAY /LIFR-IFR CIGS EXTEND WESTWARD TO LAKE MICHIGAN/...WILL CARRY SCATTERED LIGHT SHOWERS ACROSS THE BOARD. AM NOT TOO IMPRESSED WITH THUNDER CHANCES THIS AFTERNOON...GIVEN THE NEARLY MOIST ADIABATIC PROFILE AND LOSS OF THE DEEP MOISTURE. HOWEVER THERE STILL LOOKS TO BE A SHOT ACROSS THE NORTHERN/NORTHEASTERN CWA BY LATE AFTERNOON... AS SOME MID-LEVEL COOLING ASSOCIATED WITH THE NORTHERN SHORTWAVE HELPS TO STEEPEN LAPSE RATES A BIT. SHORT TERM...TODAY AND TONIGHT WEAK DEVELOPING SURFACE LOW PRESSURE EXPECTED TO MOVE ACROSS FAR SOUTHERN LAKES REGION TODAY VIA FAIR MODEL CONSENSUS. NAM/RUC SEEM A BIT THE BEST IN HANDLING PRESSURE PATTERN CURRENTLY...SO WILL BE PREFERRED FOR DETAILS. THIS LOW THEN WILL CONTINUE ON TO THE EAST TONIGHT AHEAD OF APPROACHING RIDGE WEST OF THE AREA. AT 500 MB...PATTERN RATHER DIRTY...WITH NUMEROUS WEAK VORTICITY IMPULSES IN WESTERLY FLOW TODAY BUT LARGELY EXITING AREA THIS MORNING. THEN... MAIN SHORTWAVE TROUGH WEST OF THE NORTHERN LAKES REGION SWINGING SOUTHEAST OVER AREA TONIGHT. DEEPER MOISTURE...AS PER 850 TO 500 MB LAYER...PRETTY GOOD TODAY...ESPECIALLY THIS MORNING AND ESPECIALLY SOUTH...LESSENING THIS AFTERNOON AND MORE SO TONIGHT. LOWER MOISTURE AS AT 925 MB QUITE GOOD THROUGH TONIGHT...SO CLOUDS SHOULD PREVAIL. 850 TO 700 MB OMEGA FIELDS SHOW QUITE ROBUST ASCENT THIS MORNING...GENERALLY 5 TO 10 UBAR/S...THEN LINGERING BUT LESSENING THIS AFTERNOON BEFORE ENDING TONIGHT. 850 TO 500 MB QVECTOR CONVERGENCE/IMPLIED ASCENT WEAK AND MAINLY THIS MORNING. 850 TO 700 MB DEFORMATION SEEN MUCH OF TODAY...ESPECIALLY SOUTH...WITH MODEST LOW LEVEL WIND CONVERGENCE ACCOMPANYING LOW TODAY AND CARRYING OVER INTO THIS EVENING WITH LOW LEVEL CYCLONIC FLOW LINGERING. MODELS DOING POORLY OVERNIGHT WITH QPF AREAL DEPICTION. FORECAST IS TAILORED MORE TOWARD THE SUPPORTING DYNAMICS...WHICH ARE IN BETTER AGREEMENT WITH CURRENT TRENDS. THUS...NUMEROUS POPS IN SOUTHERN 4 COUNTIES THIS MORNING AND CHANCE REMAINDER OF AREA...CHANCE POPS ENTIRE AREA THIS AFTERNOON AND EVENING...ONLY SLIGHT CHANCE LATE TONIGHT. THUNDER WILL BE MENTIONED ALL AREAS TODAY...THOUGH INSTABILITY PARAMETERS ON THE WEAK SIDE...SUCH AS CAPE AND LIFTED INDICES... AND LAPSE RATES IN 850 TO 500 MB LAYER LACKING STEEPNESS. GUIDANCE TEMPERATURES ADHERED TO CLOSELY THROUGH TONIGHT. LONG TERM...SUNDAY THROUGH FRIDAY THE WESTERLIES WILL BE QUITE ACTIVE ACROSS THE NORTHERN CONUS THIS UPCOMING WEEK AS SEVERAL SHORT WAVES SEEN IN THE H2O VAPOR LOOP ACROSS ALASKA INTO THE GULF OF ALASKA TRACK ACROSS THE U.S./CANADIAN BORDER. WHILE TIMING AND EVENTUAL SYNOPTIC IMPACTS REMAIN TO BE SEEN...LATEST TRENDS IN THE NUMERICAL SUITE ARE POINTING TOWARD A WEAKER FROPA TUESDAY THEN A POTENT FROPA FRIDAY-SATURDAY TIME FRAME. FIRST ISSUE IS CURRENT SHORT WAVE APPROACHING THE ARROWHEAD OF MINNESOTA. WHILE THIS IS A SHORT TERM CONCERN...ITS AFFECTS MAY LAST INTO SUNDAY MORNING AS THIS WAVE DEPARTS. WHILE SUBSIDENCE IS EXPECTED...CYCLONIC FLOW ALOFT AND SOME LOW-MID LEVEL MOISTURE INTERACTING WITH THE APPROACH OF THE 500MB COLD POOL COULD BE ENOUGH FOR A BRIEF SHOWER IN THE MORNING. HENCE THE LOW POP AND A SLIGHT CHANCE WORDING. THEN SKIES WILL IMPROVE THROUGH THE AFTERNOON WITH FASTER IMPROVEMENT NEAR LAKE HURON WITH THE SHOT OF COOL ADVECTION AND MINIMAL LAPSE RATES. FURTHER INLAND...WITH THE INSOLATION AND DIFFERENTIAL HEATING COULD SET UP A HEALTHY CU FIELD BUT WITH AMPLE DRY AIR ALOFT...THIS TOO SHOULD MIX OUT QUICKLY BY LATE AFTERNOON. WITH 850MB TEMPS DROPPING BACK TO AROUND 10C...AND A LATE START TO THE SUNSHINE...TEMPERATURES SHOULD TOP OUT INTO THE MID-UPPER 70S (A FEW DEGREES COOLER NEAR LAKE HURON). HIGH PRESSURE SETTLES INTO THE STATE SUNDAY NIGHT INTO MONDAY WITH A NEAR DRY COLUMN AND LIGHT WINDS. CONCERN SUNDAY NIGHT COULD BE SOME PATCHY FOG...ESPECIALLY IF WE DO GET SOME PRECIP...WITH IDEAL RADIATIONAL COOLING CONDITIONS. TEMPERATURES SHOULD DROP BACK INTO THE 50S FOR MOST LOCATIONS SUNDAY NIGHT AND WITH NEARLY FULL SUNSHINE MONDAY CLIMB QUICKLY INTO THE LOWER 80S WITH A 2-3 DEGREE REBOUND AT 850MBS. AFOREMENTIONED FRONTAL SYSTEM CURRENTLY ACROSS NORTH-CENTRAL CANADA BEGINS ITS APPROACHES THE UPPER LAKES REGION LATE MONDAY AND SAGS SOUTHWARD THROUGH TUESDAY. AS MENTIONED IN PREVIOUS AFD/S...MOISTURE AND UPPER SUPPORT WILL BECOME FURTHER REMOVED THROUGH TUESDAY SO CHANCES FOR CONVECTION LOOK SMALL (30%) AT THIS TIME. THE GFS BEGINS TO SHOW ITS CONVECTIVE ISSUES WHILE THE NMM LOOKS A LITTLE BETTER BUT TOO SLOW WITH THE MOVEMENT OF THIS FRONT WHEN COMPARED TO THE ECMWF/UKMET/WRF-HEMI. IN FACT IF THE WRF-HEMI IS CORRECT...THIS FRONT WILL CLEAR THE REGION EARLY TUESDAY WHICH IS NOT UNREASONABLE GIVEN THE STRENGTH OF WAVE IN THE GULF OF ALASKA TRACKING ACROSS CENTRAL CANADA. THEN THE GREAT LAKES RETURN TOWARD HIGHER PRESSURE FOR THE MID WEEK PERIOD WITH SEASONABLE TEMPERATURES AND COMFORTABLE HUMIDITY LEVELS FROM CANADA. THEN CHANGES ARE EXPECTED BY WEEKS END INTO THE WEEKEND. LATEST ECMWF AND GFS SUGGEST A RATHER ROBUST COLD FRONT TO IMPACT THE PLAINS AND MISSISSIPPI RIVER VALLEY LATE THURSDAY INTO FRIDAY. TIMING REMAINS AN ISSUE AS THE GFS IS QUITE STRONG WITH THE CONVECTIVE FEATURES THAT MAY PLAY HAVOC WITH THE SYNOPTIC PATTERN. HOWEVER...FAIRLY GOOD AGREEMENT WITH ADDITIONAL SHORT WAVE SUPPORT DIVING INTO THE BACKSIDE OF THIS FRONT INTO THE NORTHERN PLAINS THE START OF THIS UPCOMING WEEKEND. THIS COULD PROVE TO BE A ACTIVE SEVERE WEATHER PATTERN FOR THE EASTERN CONUS WITH STRONG LOW LEVEL JET SIGNALS (30-40KTS) AND AMPLE MOISTURE TRANSPORT FROM THE GULF OF MEXICO. SO THE CHANCE FOR SHOWERS/THUNDERSTORMS HOLDS THROUGH FRIDAY AND EXTENDED INTO SATURDAY AT THIS TIME. WITH 850MB TEMPS CLIMBING BACK INTO THE UPPER TEENS...WE COULD SEE TEMPERATURES CLIMBING INTO THE MID AND PERHAPS UPPER 80S ASSUMING AMPLE SUNSHINE OCCURS. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ UPDATE.......BRAVENDER AVIATION.....DWD SHORT TERM...DWD LONG TERM....BGM YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1147 AM EDT SAT AUG 19 2006 .DISCUSSION... THE MAIN CONCERN WITH THIS FORECAST UPDATE IS THE RAIN POTENTIAL FOR TODAY. WATER VAPOR IMAGERY AND RUC SHOWING A SHORTWAVE OVER CENTRAL LAKE SUPERIOR AND ANOTHER OVER THE DULUTH AREA. A ZONAL FLOW CONTINUES FROM THE DULUTH AREA WEST TO WEST COAST. A SURFACE LOW IS OVER SOUTHEAST LOWER MICHIGAN SHIFTING SOUTHEAST. A 1020MB RIDGE STRETCHES FROM CENTRAL ONTARIO INTO THE DAKOTAS. RAIN IS OCCURRING UNDER A CLOUDS SHIELD WHICH SLOWLY MOVING EAST. THE CLOUD SHIELD LINES UP WELL WITH THE 70 PERCENT SURFACE TO 500MB MEAN RH. DRY AIR IS ADVECTING INTO THE AREA FROM THE WEST. THE SHORTWAVES OVER LAKE SUPERIOR AND DULUTH WILL MOVE RAPIDLY THROUGH THE FORECAST AREA TODAY REACHING NORTHERN LOWER MICHIGAN BY LATE AFTERNOON. A MID LEVEL LOW WILL DEVELOP OVER THE CYXZ AREA. ANOTHER WEAK SHORTWAVE WILL SLIDE INTO THE DULUTH AREA LATE. THE SURFACE RIDGE WILL SHIFT INTO CENTRAL AND WESTERN LAKE SUPERIOR THIS AFTERNOON. RUC/NAM SHOW THAT THERE WILL BE ENOUGH MOISTURE TO PRODUCE SHOWERS THIS AFTERNOON...HOWEVER...GFS DOES NOT SHOW THIS. IT INDICATES THAT IT MAY BE TOO DRY. SATELLITE DOES NOT SHOW ANY PRECIPITATION WITH THIS SHORTWAVE SO FAR...WHICH IS WHAT GFS SHOWS...SO WILL FAVOR THE GFS SOLUTION FOR NOW. CLOUD COVER AND COLD AIR ADVECTION WILL HELP TO HOLD THE TEMPERATURES DOWN...SO WILL NOT MAKE ANY MAJOR CHANGES AT THIS TIME. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1132 AM EDT SAT AUG 19 2006 .UPDATE... BROAD SURFACE LOW OVER SOUTHERN LOWER MICHIGAN WILL MOVE INTO ONTARIO/LAKE ERIE THIS AFTERNOON. WIDESPREAD SHOWERS IN THE DEEP WARM/MOIST ADVECTION AHEAD OF THIS SYSTEM ARE JUST EXITING THE EASTERN CWA...WITH REGIONAL RADARS/METARS SHOWING LIGHT SHOWERS/DRIZZLE LINGERING BACK TO THE WEST. 14Z TAMDAR ASCENT SOUNDINGS TO THE WEST OUT OF DTW SHOW THE DEEP MOISTURE ALREADY STRIPPING AWAY...BUT WITH THE COLUMN 700MB AND BELOW REMAINING SATURATED. 12Z RUC/NAM HAVE A DECENT HANDLE ON THE SURFACE LOW POSITION...AND BOTH SHOW A TROUGH LINGERING BACK ACROSS SOUTHEAST MICHIGAN INTO THIS EVENING...AHEAD OF THE STRONGER NORTHERN STREAM SYSTEM OVER THE NORTHERN GREAT LAKES. GIVEN THE ABUNDANT LOW-LEVEL MOISTURE THAT IS EXPECTED TO PERSIST THROUGH MUCH OF THE DAY /LIFR-IFR CIGS EXTEND WESTWARD TO LAKE MICHIGAN/...WILL CARRY SCATTERED LIGHT SHOWERS ACROSS THE BOARD. AM NOT TOO IMPRESSED WITH THUNDER CHANCES THIS AFTERNOON...GIVEN THE NEARLY MOIST ADIABATIC PROFILE AND LOSS OF THE DEEP MOISTURE. HOWEVER THERE STILL LOOKS TO BE A SHOT ACROSS THE NORTHERN/NORTHEASTERN CWA BY LATE AFTERNOON... AS SOME MID-LEVEL COOLING ASSOCIATED WITH THE NORTHERN SHORTWAVE HELPS TO STEEPEN LAPSE RATES A BIT. && .PREV DISCUSSION...ISSUED 754 AM EDT SAT AUG 19 2006 AVIATION... PROLONGED WETTING AT SOUTHERN TAF SITES...WITH IMPROVED MOISTURE/LIGHT WINDS ACROSS ALL OF SOUTHEAST MI OVERNIGHT...HAS LED TO FREQUENT IFR CEILINGS SOUTH AND MAINLY IFR VISIBILITIES THROUGHOUT DURING THE PAST FEW HOURS. WITH WEAK WAVE TRAVERSING THE AREA TODAY...BOTH CEILINGS AND VISIBILITIES WILL BE SLOW TO IMPROVE...THOUGH RAIN TO BE MAINLY CONFINED TO THE SOUTHERN TAF SITES. CONDITIONS GRADUALLY IMPROVING TO MVFR BY LATE MORNING AND TO LOW VFR CEILINGS LATER THIS AFTERNOON AS VISIBILITIES BECOME UNRESTRICTED. MODEL SOUNDINGS SHOW LOWERING CEILINGS AGAIN TONIGHT...THOUGH...WITH WRAPAROUND MOISTURE AND LINGERING LOW LEVEL WIND CONVERGENCE BEHIND THE WAVE. LATE TONIGHT...HAVE BROUGHT CEILINGS DOWN INTO IFR CATEGORY...SUPPORTED BY GUIDANCE AND MODEL SOUNDINGS TO A LARGE DEGREE. SHORT TERM...TODAY AND TONIGHT WEAK DEVELOPING SURFACE LOW PRESSURE EXPECTED TO MOVE ACROSS FAR SOUTHERN LAKES REGION TODAY VIA FAIR MODEL CONSENSUS. NAM/RUC SEEM A BIT THE BEST IN HANDLING PRESSURE PATTERN CURRENTLY...SO WILL BE PREFERRED FOR DETAILS. THIS LOW THEN WILL CONTINUE ON TO THE EAST TONIGHT AHEAD OF APPROACHING RIDGE WEST OF THE AREA. AT 500 MB...PATTERN RATHER DIRTY...WITH NUMEROUS WEAK VORTICITY IMPULSES IN WESTERLY FLOW TODAY BUT LARGELY EXITING AREA THIS MORNING. THEN... MAIN SHORTWAVE TROUGH WEST OF THE NORTHERN LAKES REGION SWINGING SOUTHEAST OVER AREA TONIGHT. DEEPER MOISTURE...AS PER 850 TO 500 MB LAYER...PRETTY GOOD TODAY...ESPECIALLY THIS MORNING AND ESPECIALLY SOUTH...LESSENING THIS AFTERNOON AND MORE SO TONIGHT. LOWER MOISTURE AS AT 925 MB QUITE GOOD THROUGH TONIGHT...SO CLOUDS SHOULD PREVAIL. 850 TO 700 MB OMEGA FIELDS SHOW QUITE ROBUST ASCENT THIS MORNING...GENERALLY 5 TO 10 UBAR/S...THEN LINGERING BUT LESSENING THIS AFTERNOON BEFORE ENDING TONIGHT. 850 TO 500 MB QVECTOR CONVERGENCE/IMPLIED ASCENT WEAK AND MAINLY THIS MORNING. 850 TO 700 MB DEFORMATION SEEN MUCH OF TODAY...ESPECIALLY SOUTH...WITH MODEST LOW LEVEL WIND CONVERGENCE ACCOMPANYING LOW TODAY AND CARRYING OVER INTO THIS EVENING WITH LOW LEVEL CYCLONIC FLOW LINGERING. MODELS DOING POORLY OVERNIGHT WITH QPF AREAL DEPICTION. FORECAST IS TAILORED MORE TOWARD THE SUPPORTING DYNAMICS...WHICH ARE IN BETTER AGREEMENT WITH CURRENT TRENDS. THUS...NUMEROUS POPS IN SOUTHERN 4 COUNTIES THIS MORNING AND CHANCE REMAINDER OF AREA...CHANCE POPS ENTIRE AREA THIS AFTERNOON AND EVENING...ONLY SLIGHT CHANCE LATE TONIGHT. THUNDER WILL BE MENTIONED ALL AREAS TODAY...THOUGH INSTABILITY PARAMETERS ON THE WEAK SIDE...SUCH AS CAPE AND LIFTED INDICES... AND LAPSE RATES IN 850 TO 500 MB LAYER LACKING STEEPNESS. GUIDANCE TEMPERATURES ADHERED TO CLOSELY THROUGH TONIGHT. LONG TERM...SUNDAY THROUGH FRIDAY THE WESTERLIES WILL BE QUITE ACTIVE ACROSS THE NORTHERN CONUS THIS UPCOMING WEEK AS SEVERAL SHORT WAVES SEEN IN THE H2O VAPOR LOOP ACROSS ALASKA INTO THE GULF OF ALASKA TRACK ACROSS THE U.S./CANADIAN BORDER. WHILE TIMING AND EVENTUAL SYNOPTIC IMPACTS REMAIN TO BE SEEN...LATEST TRENDS IN THE NUMERICAL SUITE ARE POINTING TOWARD A WEAKER FROPA TUESDAY THEN A POTENT FROPA FRIDAY-SATURDAY TIME FRAME. FIRST ISSUE IS CURRENT SHORT WAVE APPROACHING THE ARROWHEAD OF MINNESOTA. WHILE THIS IS A SHORT TERM CONCERN...ITS AFFECTS MAY LAST INTO SUNDAY MORNING AS THIS WAVE DEPARTS. WHILE SUBSIDENCE IS EXPECTED...CYCLONIC FLOW ALOFT AND SOME LOW-MID LEVEL MOISTURE INTERACTING WITH THE APPROACH OF THE 500MB COLD POOL COULD BE ENOUGH FOR A BRIEF SHOWER IN THE MORNING. HENCE THE LOW POP AND A SLIGHT CHANCE WORDING. THEN SKIES WILL IMPROVE THROUGH THE AFTERNOON WITH FASTER IMPROVEMENT NEAR LAKE HURON WITH THE SHOT OF COOL ADVECTION AND MINIMAL LAPSE RATES. FURTHER INLAND...WITH THE INSOLATION AND DIFFERENTIAL HEATING COULD SET UP A HEALTHY CU FIELD BUT WITH AMPLE DRY AIR ALOFT...THIS TOO SHOULD MIX OUT QUICKLY BY LATE AFTERNOON. WITH 850MB TEMPS DROPPING BACK TO AROUND 10C...AND A LATE START TO THE SUNSHINE...TEMPERATURES SHOULD TOP OUT INTO THE MID-UPPER 70S (A FEW DEGREES COOLER NEAR LAKE HURON). HIGH PRESSURE SETTLES INTO THE STATE SUNDAY NIGHT INTO MONDAY WITH A NEAR DRY COLUMN AND LIGHT WINDS. CONCERN SUNDAY NIGHT COULD BE SOME PATCHY FOG...ESPECIALLY IF WE DO GET SOME PRECIP...WITH IDEAL RADIATIONAL COOLING CONDITIONS. TEMPERATURES SHOULD DROP BACK INTO THE 50S FOR MOST LOCATIONS SUNDAY NIGHT AND WITH NEARLY FULL SUNSHINE MONDAY CLIMB QUICKLY INTO THE LOWER 80S WITH A 2-3 DEGREE REBOUND AT 850MBS. AFOREMENTIONED FRONTAL SYSTEM CURRENTLY ACROSS NORTH-CENTRAL CANADA BEGINS ITS APPROACHES THE UPPER LAKES REGION LATE MONDAY AND SAGS SOUTHWARD THROUGH TUESDAY. AS MENTIONED IN PREVIOUS AFD/S...MOISTURE AND UPPER SUPPORT WILL BECOME FURTHER REMOVED THROUGH TUESDAY SO CHANCES FOR CONVECTION LOOK SMALL (30%) AT THIS TIME. THE GFS BEGINS TO SHOW ITS CONVECTIVE ISSUES WHILE THE NMM LOOKS A LITTLE BETTER BUT TOO SLOW WITH THE MOVEMENT OF THIS FRONT WHEN COMPARED TO THE ECMWF/UKMET/WRF-HEMI. IN FACT IF THE WRF-HEMI IS CORRECT...THIS FRONT WILL CLEAR THE REGION EARLY TUESDAY WHICH IS NOT UNREASONABLE GIVEN THE STRENGTH OF WAVE IN THE GULF OF ALASKA TRACKING ACROSS CENTRAL CANADA. THEN THE GREAT LAKES RETURN TOWARD HIGHER PRESSURE FOR THE MID WEEK PERIOD WITH SEASONABLE TEMPERATURES AND COMFORTABLE HUMIDITY LEVELS FROM CANADA. THEN CHANGES ARE EXPECTED BY WEEKS END INTO THE WEEKEND. LATEST ECMWF AND GFS SUGGEST A RATHER ROBUST COLD FRONT TO IMPACT THE PLAINS AND MISSISSIPPI RIVER VALLEY LATE THURSDAY INTO FRIDAY. TIMING REMAINS AN ISSUE AS THE GFS IS QUITE STRONG WITH THE CONVECTIVE FEATURES THAT MAY PLAY HAVOC WITH THE SYNOPTIC PATTERN. HOWEVER...FAIRLY GOOD AGREEMENT WITH ADDITIONAL SHORT WAVE SUPPORT DIVING INTO THE BACKSIDE OF THIS FRONT INTO THE NORTHERN PLAINS THE START OF THIS UPCOMING WEEKEND. THIS COULD PROVE TO BE A ACTIVE SEVERE WEATHER PATTERN FOR THE EASTERN CONUS WITH STRONG LOW LEVEL JET SIGNALS (30-40KTS) AND AMPLE MOISTURE TRANSPORT FROM THE GULF OF MEXICO. SO THE CHANCE FOR SHOWERS/THUNDERSTORMS HOLDS THROUGH FRIDAY AND EXTENDED INTO SATURDAY AT THIS TIME. WITH 850MB TEMPS CLIMBING BACK INTO THE UPPER TEENS...WE COULD SEE TEMPERATURES CLIMBING INTO THE MID AND PERHAPS UPPER 80S ASSUMING AMPLE SUNSHINE OCCURS. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ UPDATE.......BRAVENDER AVIATION.....DWD SHORT TERM...DWD LONG TERM....BGM YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 754 AM EDT SAT AUG 19 2006 .AVIATION... PROLONGED WETTING AT SOUTHERN TAF SITES...WITH IMPROVED MOISTURE/LIGHT WINDS ACROSS ALL OF SOUTHEAST MI OVERNIGHT...HAS LED TO FREQUENT IFR CEILINGS SOUTH AND MAINLY IFR VISIBILITIES THROUGHOUT DURING THE PAST FEW HOURS. WITH WEAK WAVE TRAVERSING THE AREA TODAY...BOTH CEILINGS AND VISIBILITIES WILL BE SLOW TO IMPROVE...THOUGH RAIN TO BE MAINLY CONFINED TO THE SOUTHERN TAF SITES. CONDITIONS GRADUALLY IMPROVING TO MVFR BY LATE MORNING AND TO LOW VFR CEILINGS LATER THIS AFTERNOON AS VISIBILITIES BECOME UNRESTRICTED. MODEL SOUNDINGS SHOW LOWERING CEILINGS AGAIN TONIGHT...THOUGH...WITH WRAPAROUND MOISTURE AND LINGERING LOW LEVEL WIND CONVERGENCE BEHIND THE WAVE. LATE TONIGHT...HAVE BROUGHT CEILINGS DOWN INTO IFR CATEGORY...SUPPORTED BY GUIDANCE AND MODEL SOUNDINGS TO A LARGE DEGREE. && .PREV DISCUSSION...ISSUED 352 AM EDT SAT AUG 19 2006 SHORT TERM...TODAY AND TONIGHT WEAK DEVELOPING SURFACE LOW PRESSURE EXPECTED TO MOVE ACROSS FAR SOUTHERN LAKES REGION TODAY VIA FAIR MODEL CONSENSUS. NAM/RUC SEEM A BIT THE BEST IN HANDLING PRESSURE PATTERN CURRENTLY...SO WILL BE PREFERRED FOR DETAILS. THIS LOW THEN WILL CONTINUE ON TO THE EAST TONIGHT AHEAD OF APPROACHING RIDGE WEST OF THE AREA. AT 500 MB...PATTERN RATHER DIRTY...WITH NUMEROUS WEAK VORTICITY IMPULSES IN WESTERLY FLOW TODAY BUT LARGELY EXITING AREA THIS MORNING. THEN... MAIN SHORTWAVE TROUGH WEST OF THE NORTHERN LAKES REGION SWINGING SOUTHEAST OVER AREA TONIGHT. DEEPER MOISTURE...AS PER 850 TO 500 MB LAYER...PRETTY GOOD TODAY...ESPECIALLY THIS MORNING AND ESPECIALLY SOUTH...LESSENING THIS AFTERNOON AND MORE SO TONIGHT. LOWER MOISTURE AS AT 925 MB QUITE GOOD THROUGH TONIGHT...SO CLOUDS SHOULD PREVAIL. 850 TO 700 MB OMEGA FIELDS SHOW QUITE ROBUST ASCENT THIS MORNING...GENERALLY 5 TO 10 UBAR/S...THEN LINGERING BUT LESSENING THIS AFTERNOON BEFORE ENDING TONIGHT. 850 TO 500 MB QVECTOR CONVERGENCE/IMPLIED ASCENT WEAK AND MAINLY THIS MORNING. 850 TO 700 MB DEFORMATION SEEN MUCH OF TODAY...ESPECIALLY SOUTH...WITH MODEST LOW LEVEL WIND CONVERGENCE ACCOMPANYING LOW TODAY AND CARRYING OVER INTO THIS EVENING WITH LOW LEVEL CYCLONIC FLOW LINGERING. MODELS DOING POORLY OVERNIGHT WITH QPF AREAL DEPICTION. FORECAST IS TAILORED MORE TOWARD THE SUPPORTING DYNAMICS...WHICH ARE IN BETTER AGREEMENT WITH CURRENT TRENDS. THUS...NUMEROUS POPS IN SOUTHERN 4 COUNTIES THIS MORNING AND CHANCE REMAINDER OF AREA...CHANCE POPS ENTIRE AREA THIS AFTERNOON AND EVENING...ONLY SLIGHT CHANCE LATE TONIGHT. THUNDER WILL BE MENTIONED ALL AREAS TODAY...THOUGH INSTABILITY PARAMETERS ON THE WEAK SIDE...SUCH AS CAPE AND LIFTED INDICES... AND LAPSE RATES IN 850 TO 500 MB LAYER LACKING STEEPNESS. GUIDANCE TEMPERATURES ADHERED TO CLOSELY THROUGH TONIGHT. LONG TERM...SUNDAY THROUGH FRIDAY THE WESTERLIES WILL BE QUITE ACTIVE ACROSS THE NORTHERN CONUS THIS UPCOMING WEEK AS SEVERAL SHORT WAVES SEEN IN THE H2O VAPOR LOOP ACROSS ALASKA INTO THE GULF OF ALASKA TRACK ACROSS THE U.S./CANADIAN BORDER. WHILE TIMING AND EVENTUAL SYNOPTIC IMPACTS REMAIN TO BE SEEN...LATEST TRENDS IN THE NUMERICAL SUITE ARE POINTING TOWARD A WEAKER FROPA TUESDAY THEN A POTENT FROPA FRIDAY-SATURDAY TIME FRAME. FIRST ISSUE IS CURRENT SHORT WAVE APPROACHING THE ARROWHEAD OF MINNESOTA. WHILE THIS IS A SHORT TERM CONCERN...ITS AFFECTS MAY LAST INTO SUNDAY MORNING AS THIS WAVE DEPARTS. WHILE SUBSIDENCE IS EXPECTED...CYCLONIC FLOW ALOFT AND SOME LOW-MID LEVEL MOISTURE INTERACTING WITH THE APPROACH OF THE 500MB COLD POOL COULD BE ENOUGH FOR A BRIEF SHOWER IN THE MORNING. HENCE THE LOW POP AND A SLIGHT CHANCE WORDING. THEN SKIES WILL IMPROVE THROUGH THE AFTERNOON WITH FASTER IMPROVEMENT NEAR LAKE HURON WITH THE SHOT OF COOL ADVECTION AND MINIMAL LAPSE RATES. FURTHER INLAND...WITH THE INSOLATION AND DIFFERENTIAL HEATING COULD SET UP A HEALTHY CU FIELD BUT WITH AMPLE DRY AIR ALOFT...THIS TOO SHOULD MIX OUT QUICKLY BY LATE AFTERNOON. WITH 850MB TEMPS DROPPING BACK TO AROUND 10C...AND A LATE START TO THE SUNSHINE...TEMPERATURES SHOULD TOP OUT INTO THE MID-UPPER 70S (A FEW DEGREES COOLER NEAR LAKE HURON). HIGH PRESSURE SETTLES INTO THE STATE SUNDAY NIGHT INTO MONDAY WITH A NEAR DRY COLUMN AND LIGHT WINDS. CONCERN SUNDAY NIGHT COULD BE SOME PATCHY FOG...ESPECIALLY IF WE DO GET SOME PRECIP...WITH IDEAL RADIATIONAL COOLING CONDITIONS. TEMPERATURES SHOULD DROP BACK INTO THE 50S FOR MOST LOCATIONS SUNDAY NIGHT AND WITH NEARLY FULL SUNSHINE MONDAY CLIMB QUICKLY INTO THE LOWER 80S WITH A 2-3 DEGREE REBOUND AT 850MBS. AFOREMENTIONED FRONTAL SYSTEM CURRENTLY ACROSS NORTH-CENTRAL CANADA BEGINS ITS APPROACHES THE UPPER LAKES REGION LATE MONDAY AND SAGS SOUTHWARD THROUGH TUESDAY. AS MENTIONED IN PREVIOUS AFD/S...MOISTURE AND UPPER SUPPORT WILL BECOME FURTHER REMOVED THROUGH TUESDAY SO CHANCES FOR CONVECTION LOOK SMALL (30%) AT THIS TIME. THE GFS BEGINS TO SHOW ITS CONVECTIVE ISSUES WHILE THE NMM LOOKS A LITTLE BETTER BUT TOO SLOW WITH THE MOVEMENT OF THIS FRONT WHEN COMPARED TO THE ECMWF/UKMET/WRF-HEMI. IN FACT IF THE WRF-HEMI IS CORRECT...THIS FRONT WILL CLEAR THE REGION EARLY TUESDAY WHICH IS NOT UNREASONABLE GIVEN THE STRENGTH OF WAVE IN THE GULF OF ALASKA TRACKING ACROSS CENTRAL CANADA. THEN THE GREAT LAKES RETURN TOWARD HIGHER PRESSURE FOR THE MID WEEK PERIOD WITH SEASONABLE TEMPERATURES AND COMFORTABLE HUMIDITY LEVELS FROM CANADA. THEN CHANGES ARE EXPECTED BY WEEKS END INTO THE WEEKEND. LATEST ECMWF AND GFS SUGGEST A RATHER ROBUST COLD FRONT TO IMPACT THE PLAINS AND MISSISSIPPI RIVER VALLEY LATE THURSDAY INTO FRIDAY. TIMING REMAINS AN ISSUE AS THE GFS IS QUITE STRONG WITH THE CONVECTIVE FEATURES THAT MAY PLAY HAVOC WITH THE SYNOPTIC PATTERN. HOWEVER...FAIRLY GOOD AGREEMENT WITH ADDITIONAL SHORT WAVE SUPPORT DIVING INTO THE BACKSIDE OF THIS FRONT INTO THE NORTHERN PLAINS THE START OF THIS UPCOMING WEEKEND. THIS COULD PROVE TO BE A ACTIVE SEVERE WEATHER PATTERN FOR THE EASTERN CONUS WITH STRONG LOW LEVEL JET SIGNALS (30-40KTS) AND AMPLE MOISTURE TRANSPORT FROM THE GULF OF MEXICO. SO THE CHANCE FOR SHOWERS/THUNDERSTORMS HOLDS THROUGH FRIDAY AND EXTENDED INTO SATURDAY AT THIS TIME. WITH 850MB TEMPS CLIMBING BACK INTO THE UPPER TEENS...WE COULD SEE TEMPERATURES CLIMBING INTO THE MID AND PERHAPS UPPER 80S ASSUMING AMPLE SUNSHINE OCCURS. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION...DWD SHORT TERM...DWD LONG TERM....BGM YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE HASTINGS NE 949 AM CDT SAT AUG 19 2006 .UPDATED...TO KEEP SHOWERS SOUTH OF HIGHWAY 36 THROUGH MIDDAY AND ADD SOME DRIZZLE WHICH IS OCCURRING HERE AND THERE. DID LOWER TEMPERATURES JUST A BIT BACK TO MIDDLE 70S MANY AREAS WITH CLOUDS AND NORTH WINDS. && .PREV DISCUSSION... (ISSUED 551 AM CDT SAT AUG 19 2006) DISCUSSION...WILL BE UPDATING THE FORECAST TO REMOVE THE FLASH FLOOD WATCH FOR MITCHELL AND JEWELL COUNTIES. THE RAIN HAS ENDED AND THE 06Z GFS SUGGESTS THE BEST CHANCE FOR ANY ADDITIONAL HEAVY RAINFALL WILL BE SOUTH OF THE FORECAST AREA. STILL CAN NOT RULE OUT THE POSSIBILITY OF A FEW SHOWERS OR THUNDERSTORMS IN THE SOUTH DUE TO THE PROXIMITY OF THE H7 DEFORMATION AXIS...SO WILL KEEP A SMALL POP GOING INTO THE AFTERNOON. PREV DISCUSSION... (ISSUED 328 AM CDT SAT AUG 19 2006) DISCUSSION...PRIMARY ISSUE IN THE NEAR TERM IS THE FLASH FLOOD WATCH. AREA WSR-88DS CONTINUE TO SHOW A DIMINISHING TREND TO THE PRECIPITATION THIS MORNING AS CLOUD TOPS CONTINUE TO WARM. THE 00Z GFS AND NAM STILL DISAGREE ABOUT HOW LONG THE RAIN WILL LAST...WITH THE GFS PUSHING THE MID-LEVEL DEFORMATION AXIS SOUTH MORE QUICKLY. WILL GO WITH TIMING THAT IS A BIT SLOWER THAN THE 00Z GFS SINCE THE LATEST RUC CONTINUES TO SHOW THE MID-LEVEL DEFORMATION AXIS CONTINUING THIS MORNING. THE BIG QUESTION IS HOW TO HANDLE THE CURRENT FLASH FLOOD WATCH. AS MENTIONED PREVIOUSLY THE RAINFALL RATES HAVE TAILED OFF QUITE A BIT...HOWEVER JEWELL AND MITCHELL COUNTIES ARE STILL SEEING SOME HEAVY RAINFALL...SO WILL CONTINUE THE WATCH FOR THOSE TWO COUNTIES...BUT CANCEL THE REMAINDER OF THE WATCH. TEMPERATURES WILL BE TRICKY AGAIN TODAY AND BE DEPENDENT ON CLOUD COVER. 11-3.9 MICRON SATELLITE IMAGERY INDICATES CLOUDS STRETCHING ACROSS MUCH OF THE REGION...AND CROSS SECTIONS INDICATE THAT MUCH OF THE MORNING WILL BE MAINLY CLOUDY WITH SOME INCREASE IN SUNSHINE DURING THE AFTERNOON...ESPECIALLY IN THE NORTH AND WEST. WILL GENERALLY GO WITH HIGHS IN THE MID 70S TO AROUND 80. CLOUDS SHOULD CONTINUE TO CLEAR TONIGHT...AND WITH THE SURFACE RIDGE AXIS STRETCHING THROUGH THE FORECAST AREA WINDS SHOULD BE LIGHT...SO THINK THERE IS A GOOD POSSIBILITY OF AT LEAST PATCHY FOG LATE TONIGHT INTO SUNDAY MORNING. ONCE THE FOG LIFTS...THERE SHOULD BE ENOUGH SUNSHINE TO HELP WARM TEMPERATURES BACK INTO THE LOWER TO MID 80S ON SUNDAY. THE WARMING TREND THEN CONTINUES INTO MONDAY WITH READINGS IN THE MID TO UPPER 80S. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HASTINGS NE 551 AM CDT SAT AUG 19 2006 .DISCUSSION...WILL BE UPDATING THE FORECAST TO REMOVE THE FLASH FLOOD WATCH FOR MITCHELL AND JEWELL COUNTIES. THE RAIN HAS ENDED AND THE 06Z GFS SUGGESTS THE BEST CHANCE FOR ANY ADDITIONAL HEAVY RAINFALL WILL BE SOUTH OF THE FORECAST AREA. STILL CAN NOT RULE OUT THE POSSIBLITY OF A FEW SHOWERS OR THUNDERSTORMS IN THE SOUTH DUE TO THE PROXIMITY OF THE H7 DEFORMATION AXIS...SO WILL KEEP A SMALL POP GOING INTO THE AFTERNOON. && .PREV DISCUSSION... (ISSUED 328 AM CDT SAT AUG 19 2006) DISCUSSION...PRIMARY ISSUE IN THE NEAR TERM IS THE FLASH FLOOD WATCH. AREA WSR-88DS CONTINUE TO SHOW A DIMINISHING TREND TO THE PRECIPITATION THIS MORNING AS CLOUD TOPS CONTINUE TO WARM. THE 00Z GFS AND NAM STILL DISAGREE ABOUT HOW LONG THE RAIN WILL LAST...WITH THE GFS PUSHING THE MID-LEVEL DEFORMATION AXIS SOUTH MORE QUICKLY. WILL GO WITH TIMING THAT IS A BIT SLOWER THAN THE 00Z GFS SINCE THE LATEST RUC CONTINUES TO SHOW THE MID-LEVEL DEFORMATION AXIS CONTINUING THIS MORNING. THE BIG QUESTION IS HOW TO HANDLE THE CURRENT FLASH FLOOD WATCH. AS MENTIONED PREVIOUSLY THE RAINFALL RATES HAVE TAILED OFF QUITE A BIT...HOWEVER JEWELL AND MITCHELL COUNTIES ARE STILL SEEING SOME HEAVY RAINFALL...SO WILL CONTINUE THE WATCH FOR THOSE TWO COUNTIES...BUT CANCEL THE REMAINDER OF THE WATCH. TEMPERATURES WILL BE TRICKY AGAIN TODAY AND BE DEPENDENT ON CLOUD COVER. 11-3.9 MICRON SATELLITE IMAGERY INDICATES CLOUDS STRETCHING ACROSS MUCH OF THE REGION...AND CROSS SECTIONS INDICATE THAT MUCH OF THE MORNING WILL BE MAINLY CLOUDY WITH SOME INCREASE IN SUNSHINE DURING THE AFTERNOON...ESPECIALLY IN THE NORTH AND WEST. WILL GENERALLY GO WITH HIGHS IN THE MID 70S TO AROUND 80. CLOUDS SHOULD CONTINUE TO CLEAR TONIGHT...AND WITH THE SURFACE RIDGE AXIS STRETCHING THROUGH THE FORECAST AREA WINDS SHOULD BE LIGHT...SO THINK THERE IS A GOOD POSSIBILITY OF AT LEAST PATCHY FOG LATE TONIGHT INTO SUNDAY MORNING. ONCE THE FOG LIFTS...THERE SHOULD BE ENOUGH SUNSHINE TO HELP WARM TEMPERATURES BACK INTO THE LOWER TO MID 80S ON SUNDAY. THE WARMING TREND THEN CONTINUES INTO MONDAY WITH READINGS IN THE MID TO UPPER 80S. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ KING ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE UPTON NY 305 PM EDT SAT AUG 19 2006 .NEAR TERM (TONIGHT THROUGH SUNDAY)... CLOUDS CONTINUE TO INCREASE THIS LATE SATURDAY AFTERNOON IN ADVANCE OF AN APPROACHING SHORT WAVE AND ASSOCIATED WAA. A DECENT BATCH OF SHOWERS MOVING ACRS PA THIS AFTERNOON WILL CONTINUE TO TREK EASTWARD THIS EVENING...ENTERING THE WESTERN PORTION OF THE CWA EARLY ON...THEN SPREADING ACROSS THE REST OF THE CWA BY MIDNIGHT. WILL GO WITH CATEGORICAL POPS FOR SHOWERS OVERNIGHT FOR MY NORTHERN TIER OF ZONES...SHADING DOWN TO HIGH CHANCE/LOW LIKELY TOWARD THE THE COAST. I'M NOT QUITE COMFORTABLE GOING WITH LIKELY OR CAT POPS FOR LONG ISLAND ATTM SINCE MOST OF THE FORCING IS GOING TO RIDE TO OUR NORTH. DON'T THINK THERE WILL BE MUCH IF ANY THUNDER OVERNIGHT ANYWHERE...HOWEVER KEPT A SLIGHT CHANCE AFTER COLLAB WITH SURROUNDING OFFICES. FRHT61 LI'S DON'T GO BELOW ZERO UNTIL 12-18Z SUNDAY WHICH IS A GOOD INDICATOR AS TO WHETHER IT WILL THUNDER OR NOT. GFS QPF LOOKS A BIT TOO HIGH TO ME BETWEEN 00Z AND 06Z TONIGHT. HAVE SHADED QPF MORE TOWARD THE NAM BUT DID KEEP WITH GFS TIMING AS IT DOES LOOK HAVE A MUCH BETTER HANDLE ON THE PROGRESSION OF THIS AFTERNOON'S SHOWERS JUST TO OUR WEST AND NORTH. THE BULK OF ANY STEADY RAINFALL SHOULD BE MOVING OUT OF THE REGION LATE TONIGHT AS ZONE OF STRONGEST WAA ADVECTS EASTWARD TOWARD EASTERN NEW ENGLAND AND WILL TAPER BACK POPS ACCORDINGLY. SFC LOW PRESSURE CONTINUES ITS TREK ACROSS NEW ENGLAND SUNDAY MORNING WITH TRAILING COLD FRONT EXPECTED TO MOVE ACRS THE TRI-STATE AREA DURING THE AFTERNOON HOURS. WOULD THINK AT LEAST SOME PARTIAL CLEARING IS IN ORDER FROM WEST TO EAST BY MID SUNDAY MORNING INTO THE EARLY AFTERNOON AS BULK OF WAA WILL HAVE SLID TO THE EAST OF THE AREA AND DRY SLOT MOVES ON IN. WILL ONLY BE GOING WITH CHC POPS DURING THE MORNING FOR MOST OF THE AREA...BUT WOULDN'T BE SURPRISED IF WE ARE DRY DURING MOST OF THE MORNING WITH PARTLY SUNNY SKIES. STRONG SHORT WAVE APPROACHES FROM THE NORTHWEST SUNDAY AFTERNOON. WITH COLD FRONT STILL IN THE VICINITY OF THE REGION DURING EARLY TO MID AFTERNOON...MOISTURE WILL STILL BE AROUND AND IT WILL BE QUITE MOIST. IF WE CAN GET SUBSTANTIAL BREAKS AND GO PARTLY SUNNY DURING THE LATE MORNING/AFTERNOON ALONG THE FRONT...IT SHOULD GET UNSTABLE AS HEATING WOULD BRING TEMPS WELL INTO THE 80S...IF NOT UPPER 80S AROUND 90 ACRS METRO NERN NJ. GIVEN SOME HEATING...SCT THUNDERSTORMS SHOULD DEVELOP ALONG AND NEAR THE COLD FRONT WITH THE DYNAMICS MOVING INTO THE AREA DURING THE EARLY/MID AFTERNOON HOURS. IF SUBSTANTIAL HEATING CAN OCCUR SOME OF THE STORMS COULD BE STRONG TO SEVERE WITH DAMAGING WINDS AND HAIL. DEEP LAYER SHEAR OF 40+ KNOTS WOULD PORTEND TO ORGANIZED STORMS IF ENOUGH INSTABILITY MATERIALIZES. ALL IN ALL...STRONG STORMS ARE NOT A LOCK FOR SUNDAY AFTERNOON YET DUE TO COMPLICATING FACTORS SUCH AS CLOUD COVER AND FRONTAL PLACEMENT. MESOSCALE ANALYSIS WILL BE KEY DURING THE DAY SUNDAY. ANY CONVECTION CLEARS OUT OF THE AREA BY EARLY SUNDAY EVENING AS FRONT PASSES TO THE SOUTHEAST. && .SHORT TERM (SUNDAY NIGHT THROUGH TUESDAY)... CLEARING AND DRYING SUNDAY NIGHT. FAIR WX AND NEAR SEASONAL TEMPS EXPECTED THROUGH TUESDAY AS SOUTHERN WAVE EXPECTED TO REMAIN TO OUR SOUTH. && .LONG TERM (WEDNESDAY THROUGH SATURDAY)... DRY FORECAST THROUGH THE PERIOD AS NO ORGANIZED STORM SYSTEMS LOOK TO AFFECT THE AREA AT THIS TIME. BEST CHANCE OF ANY PRECIP WILL BE WEDNESDAY ALONG A COLD FRONT. SHOT OF BLO NORM TEMPS POSSIBLE WED NIGHT THROUGH THURS. && .AVIATION... 18Z ACARS SOUNDING OVER NYC INDICATES LOW LEVEL INVERSION AROUND 4K FT HAS WEAKENED SOMEWHAT...BUT STILL PRESENT...WHICH IS KEEPING SCT STRATO CU BASES FROM RAISING. EXPECT IT TO LINGER THROUGH THE REMAINDER OF THE AFTERNOON WITH VFR PREVAILING. THE LARGE AREA OF SHOWERS ACROSS CENTRAL PA MARCHING EASTWARD AT A GOOD CLIP MAY WEAKEN A BIT DUE TO DRIER AIR ALOFT BEFORE MAKING IT TO WESTERN TERMINALS...SO HAVE TIMED IT TO ARRIVE AT NYC TERMINALS BETWEEN 23Z AND 01Z...BUT I COULD BE SLOW BY AN HOUR OR SO. 12Z GFS CAPTURED THIS FEATURE WELL. OTHERWISE...INCREASING LOW LEVEL MOISTURE WILL LIKELY BRING CIGS/VSBYS DOWN TO MVFR THIS EVENING. RUC SEEMED TO HAVE A GOOD HANDLE ON CURRENT CONDITIONS (CIGS/VSBYS) WHICH ALSO DEVELOPS STRATUS ACROSS EASTERN TERMINALS AFTER SUNSET...BUT NOT CONFIDENT OF TIMING SO INCLUDED SCT LOW CLOUDS THIS EVENING...AND THEN ONCE THE RAIN MOVES CLOSER MADE IT PREVAILING. FIRST ROUND OF SHOWERS SHOULD END BETWEEN 12Z AND 14Z FROM W TO E...THEN EXPECT ANOTHER ROUND OF SHOWERS AND TSTMS DURING THE AFTERNOON/EVENING HOURS SUNDAY AHEAD OF AND ALONG COLD FRONT. && .MARINE... WINDS AND SEAS WILL BE INCREASING TONIGHT AS LOW PRESSURE TRACKS ACROSS UPSTATE NY. WENT WITH A COMPROMISE BETWEEN THE STRONG GFS AND MUCH WEAKER NAM WIND SPEEDS...WHICH YIELDED SUSTAINED WINDS OF 15-20 KT AND GUSTS TO 25 KT ACROSS THE EASTERN TWO OCEAN ZONES...AND 10-15 KT WITH GUSTS NEAR 20 KT ELSEWHERE. SEAS WILL BUILD IN RESPONSE TO THE BRISK S/SW FLOW...REACHING 5 FT EAST OF FIRE ISLAND INLET BY SUN MORNING...AND SCA HAS BEEN POSTED FROM 4AM SUN THROUGH 4AM MON FOR THESE AREAS. SW FLOW OF 15-20 KT AND SEAS NEAR 5 FT WILL CONTINUE ACROSS THE EASTERN OCEAN ZONES SUN...THEN WINDS WILL VEER TO W/NW AND BEGIN TO DIMINISH SUN NIGHT AS THE COLD FRONT MOVES THROUGH THE AREA. SEAS WILL TAKE A WHILE TO SUBSIDE...BUT SHOULD DROP BELOW 5 FT EVERYWHERE BY EARLY MON MORNING. QUIET CONDITIONS FOR MON AND TUE WITH HIGH PRESSURE IN CONTROL. A WEAK FRONT WILL MOVE THROUGH WED...WITH WINDS/SEAS EXPECTED AT THIS TIME TO REMAIN BELOW SCA LEVELS. HIGH PRESSURE BUILDS IN ONCE AGAIN THU THROUGH FRI WITH CONTINUED TRANQUIL CONDITIONS ACROSS THE WATERS. && .HYDROLOGY... PRECIP TONIGHT THROUGH SUNDAY AFTERNOON WILL GENERALLY AVERAGE 1/2 TO 1 INCH OVER THE REGION...WITH HEAVIER RAIN POSSIBLE OVER NORTHERN PORTIONS OF THE CWA. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NJ...NONE. NY...NONE. MARINE...SMALL CRAFT ADVISORY FOR ANZ350-353 FROM 4 AM SUNDAY TO 4 AM MONDAY. && $$ PUBLIC...EKSTER AVIATION...AL MARINE...CNJ ny AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BINGHAMTON NY 850 AM EDT SAT AUG 19 2006 .SHORT TERM (TODAY - SUNDAY)... UPDATE - PLENTY OF CLD COVER AND -SHRA ACRS THE BGM FCST AREA ATTM, WITH BEST CVRG ACRS UPSTATE NY. PCPN WILL BE INCRSNG IN CVRG AND INTENSITY THIS AFTN AND EVNG AS THE S/WV OVER THE GTLAKES APRCHS. WILL RAISE POPS TO CAT ACRS MUCH OF UPSTATE FOR THIS AFTN, MAINTAINING THE GRADIENT TO CHC POPS ACRS FAR SE ZONES. GIVEN THE CLD CVR, WILL SHAVE A FEW DEG OFF TDA'S MAXES, WITH MOST AREAS TOPPING OUT IN THE M70S. PREFER THE RUC/GFS PROFILES FOR THIS AFTN, SHOWING LTL IN THE WAY OF INSTABILTY (NAM APPEARS WAY OVERDONE WITH CAPES), SO WILL ONLY MENTION THE SLGT CHC OF A TSRA THIS AFTN/EVNG. APPEARS THE SFC LOW WILL TRACK CLOSE TO THE TWIN TIERS LATER TDA, WHICH WOULD FAVOR CNTRL NY FOR THE BEST QPF, BUT AMTS NOT XPCTD TO CAUSE ANY PRBLMS. NO OTHER CHGS PEYOND PD 1. PREV AFD BLO. PREV UPDATE - RAISED POPS TO CHC FOR FAR SE ZONES THIS MRNG DUE TO SCT -SHRA ACTIVITY WHICH WILL BE WORKING INTO THIS AREA DURING THE NXT FEW HRS. NO OTHER CHGS. PREV AFD BLO. WATER VAPOR LOOP INDICATES WESTERLY FLOW ACROSS THE GREAT LAKES AND NORTHEAST U.S. EARLY THIS MORNING. A WEAK SHORT WAVE IS TRACKING EAST ACROSS THE SOUTHERN GREAT LAKES... WITH A STRONGER WAVE TRACKING EAST ACROSS MINNESOTA. A COLD FRONT IS LOCATED NORTH OF LAKE ONTARIO WHILE SFC HIGH PRESSURE MOVES EAST OFF THE EAST COAST. SOUTHWEST FLOW AHEAD OF THE FRONT IS BRINGING IN INCREASINGLY HIGH DEW POINTS ACROSS THE AREA... WITH CURRENT VALUES RANGING FROM THE MID 60S ACROSS THE NORTHERN NY LAKE PLAIN... TO THE MID 50S ACROSS THE WESTERN CATSKILLS. EXPECT SCATTERED SHOWERS ACROSS THE NORTHWEST HALF OF THE CWA THROUGH THIS MORNING AS THE SHORT WAVE OVER THE SOUTHERN GREAT LAKES MOVES EAST AND WEAKENS. RAIN CHANCES WILL INCREASE AND SPREAD SOUTHEAST LATER THIS AFTERNOON THROUGH THIS EVENING AS THE STRONG SHORT WAVE CURRENTLY OVER MINNESOTA MOVES EAST ACROSS THE GREAT LAKES. AS THE WAVE APPROACHES... SURFACE LOW PRESSURE WILL TRACK NORTHEAST FROM THE OHIO VALLEY TO UPSTATE NY. A BAND OF MID-LVL FRONTOGENESIS WILL SWEEP NORTHEAST ACROSS UPSTATE NY THIS EVENING... AND LOW-LEVEL SSW MID-LVL FLOW WILL INCREASE TO AROUND 30 KTS WHICH WILL RESULT IN SIGNIFICANT AMOUNTS OF MID-LVL ISENTROPIC LIFT. SOME SIGNIFICANT DIFFERENCES ARE NOTED BETWEEN THE WRF AND GFS REGARDING TIMING OF THIS WAVE... AS WELL AS INSTABILITY AHEAD OF THE WAVE THIS AFTERNOON. THE WRF IS SLOWER WITH THE EASTWARD MOVEMENT OF THE WAVE... AND ALSO GENERATES MORE INSTABILITY LATE TODAY THAN THE GFS. BASICALLY WENT WITH A COMPROMISE SOLUTION BETWEEN THE WRF AND GFS WITH THIS FORECAST. BASED ON THIS EXPECT CAPE VALUES BETWEEN 500 AND 1000 J/KG LATER TODAY. THIS MODEST INSTABILITY... ALONG WITH A 25 TO 30 KT MID-LVL FLOW MAY PRODUCE ENOUGH CONVECTIVE ORGANIZATION FOR ONE OR TWO STORMS TO GO SEVERE LATER TODAY... BUT NOT EXPECTING ENOUGH INSTABILITY FOR A WIDESPREAD SVR OUTBREAK. SOME HEAVY DOWNPOURS CAN ALSO BE EXPECTED LATER TODAY THRU THIS EVENING AS PWAT VALUES APPROACH 2 INCHES. BOTH THE WRF AND GFS PLACE AN AXIS OF 1.5 TO 2.5 INCHES OF RAIN ACROSS CENTRAL AND EASTERN NY LATE TODAY THRU THIS EVENING... WITH THE WRF A LITTLE FARTHER NORTH. WITH SOME CONVECTION EXPECTED WOULD NOT BE SURPRISED TO SEE SOME ISOLATED 3 INCH TOTALS AND MINOR FLOODING PROBLEMS... BUT DRY WX DURING THE PAST COUPLE OF WEEKS HAS 3-6 HR FLASH FLOOD GUIDANCE WELL OVER 3 INCHES SO AM NOT EXPECTING A BIG FLOOD RISK. THE WRF IS SLOWER MOVING THE SYSTEM EAST OF THE AREA LATE TONIGHT AND SUNDAY... AND THEREFORE INDICATES MORE LINGERING SHOWERS INTO SUNDAY. AGAIN WENT WITH A COMPROMISE BETWEEN THE WRF AND FASTER GFS AND KEPT CHC POPS GOING... MAINLY ACROSS THE NORTHERN HALF OF THE CWA... THRU SUNDAY. - MSE && .LONG TERM (SUNDAY NIGHT - FRIDAY)... IN GNRL A FAIRLY QUIET AND DRY PD IS ANTICIPATED. THE WORK WEEK SHUD START OFF WITH PLENTY OF SUNSHINE, THEN A CHC FOR -SHRA WITH THE NXT CDFNT LATE TUES/TUES NGT. HIGH PRES WILL FOLLOW WITH PARTLY TO MOSTLY SUNNY SKIES FOR THE REMAINDER OF THE WEEK. TEMPS NEAR NORMS. && .AVIATION (19/12Z TO 20/12Z)... VFR EXPECTED TO PERSIST THROUGH THIS MORNING. CONDITIONS SHOULD SLOWLY DETERIORATE TO MVFR DURING THE AFTERNOON (FROM ABOUT 18Z TO 21Z)...AS SHOWERS BECOME MORE WIDESPREAD ACROSS THE REGION. A FEW THUNDERSTORMS COULD DEVELOP BY LATE AFTERNOON...BUT SCATTERED COVERAGE AT BEST PRECLUDES THEIR MENTION IN THE TERMINALS AT THIS JUNCTURE. LIGHT WINDS EARLY TODAY SHOULD INCREASE TO ABOUT 10 KT OUT OF THE SOUTH BY AFTERNOON. TONIGHT...MVFR RESTRICTIONS...DUE TO LOWER CEILINGS...SHOWERS...AND FOG...ARE ANTICIPATED TO CONTINUE THROUGH THE NIGHT. -MJ && .BGM WATCHES/WARNINGS/ADVISORIES... .NY...NONE. .PA...NONE. $$ MSE/MJ ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 756 PM EDT SAT AUG 19 2006 .AVIATION /00Z-24Z/... CDFNT IS CURRENTLY LOCATED FROM NR KPMH TO KCVG. WINDS TURN TO THE NW BEHIND THE FRONT. SCT CONVECTION IS LOCATED ALONG THE FNT. WITH IT MOVING SOUTH WILL NOT PUT ANY PCPN IN THE KCVG/KLUK TAFS. BACKED OFF ON THE ONSET OF BR FROM THE PREVIOUS TAFS. IT LOOKS LIKES A LITTLE DRIER ARE WILL BE WORKING IN FORM THE NORTH. ONLY BROUGHT MVFR FOG IN AROUND 10-12Z IN THE NORTH. FARTHER SOUTH...WHERE THE DEWPOINTS HOLD UP A LITTLE MORE...BROUGHT MVFR HZ IN AROUND 03Z. DROPPED VSBYS TO IFR BY 08Z...WITH LIFR AT KLUK. MODELS ARE HINTING AT POSSIBLY SOME ST IN THE MORNING ACROSS THE SOUTH. HIGH PRESSURE BUILDS IN FROM THE NORTH ON SUNDAY. CURU WAS SHOWING BKN CU ACROSS THE NORTH IN THE AFTN. SITES && .PREV DISCUSSION... /ISSUED 326 PM EDT SAT AUG 19 2006/ SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/... FRNTL BNDRY PROGGED FAIRLY CLOSE TO I-71 ATTM. MAIN CONVECTION HAS FIRED AHEAD OF MID LVL S/WV IN AREA OF PVA WITH HIGHER AMOUNTS OF INSTABILITY. THESE TSTMS DVLPD ACRS SOUTH CNTRL OH AND NRN KY AND HAVE ALREADY PUSHED EAST OUT OF FCST AREA. IN WAKE OF THIS ACTIVITY...ISOLD -SHRA HAVE DVLPD RIGHT ALONG THE BNDRY FROM NEAR CMH METRO TO JUST WEST OF KILN. DO NOT EXPECT ANYTHING MORE THAN ISOLD CONVECTION AS FRNTL BNDRY TRACKS EAST ACRS REGION OVER NEXT FEW HOURS...AS BETTER PVA ALIGNED WITH CONVECTION TO EAST AND MODEL SOUNDINGS INDCG DVLP CAP AROUND 7KFT. TEMPS WERE IN THE 80S THIS AFTN. USED 18Z RUC FOR ERLY PORTION OF FCST. MID LVL S/WV AND VORT SHOULD BE EAST OF FCST AREA BY 22Z WITH STRONG NVA CURRENTLY ACRS INDIANA POISED TO MOVE ACRS REGION. HAVE MAINTAINED 20-30 POPS ALONG AND EAST OF I-71 INTO ERLY EVNG...THEN MAINTAIN LO CHC POPS ACRS SRN 1/2 FCST AREA INTO OVERNIGHT. FRNTL BNDRY WILL SAG SOUTH OF OHIO RIVER SLOWLY OVERNIGHT. SECONDARY BNDRY CURRENTLY OVER WESTERN GRT LKS WILL DROP SOUTH INTO FCST AREA LATE TONIGHT. FCST AREA AGAIN APPEARS TO NOT BE IN VERY FAVORABLE SITUATION FOR PCPN. FCST AREA WILL BE SPLIT BY TWO MAIN VORTS ASSOCD WITH MID LVL S/WV. ONE VORT WILL PASS WELL TO NORTH OF REGION ACRS SRN ONTARIO...WHILE SECOND VORT DROPS SE FROM MID MISSISSIPPI VLY INTO CNTRL KY BY ERLY SUN. SOME WEAK INSTABILITY AND LO LVL CONV NOTED WITH THE SECOND VORT DROPPING INTO KY...AND THIS MAY BE ENUF TO EITHER SPARK A FEW ISOLD SHRA/TSTMS LATE TONIGHT ACRS SRN FCST AREA...OR TSTMS THAT DVLP TO WEST OF REGION MAY CLIP SRN PORTIONS OF FCST AREA AFT MIDNIGHT. WITH THIS IN MIND...WILL MAINTAIN A 20 POP LATE TONIGHT ACRS SRN 1/2 FCST AREA. WITH ABUNDANT LO LVL MOISTURE ACRS REGION...POTENTIAL EXISTS FOR PATCHY FOG LATE TONIGHT AND INTO ERLY SUN. BOTH 12Z NAM AND GFS NOW A LITTLE QUICKER IN PUSHING S/WV EAST OF REGION ON SUN WITH SFC HI PRES AND DRIER AIRMASS BUILDING IN FROM NW. MODEL SOUNDINGS INDCG MID LVL CAP WILL STRENGTHEN DURING DAY SUN AS HI BUUILDS INTO REGION. WITH FRNTL BNDRY SAGGING INTO UPR TN VLY BY SUN AFTN/EVNG...THINKING MOST LOCATIONS WILL BE DRY THROUGHOUT DAY SUNDAY. THERE IS AN OUTSIDE CHANCE AT A -SHRA OR TWO ALONG AND SOUTH OF OHIO RIVER DURING AFTN HOURS...BUT CHANCE IS LOW ENUF TO KEEP MENTION OUT OF FCST ATTM. EXPECTING PTLY CLDY SKIES AS CU RULE AND MODEL SOUNDINGS SUGGESTING SCT/BKN CU DVLPG AS 850 CAA EXPANDS SOUTH WITH HI PRES. SKIES SHOULD BECOME MSTLY CLR SUN NIGHT AS CENTER OF SFC HI MOVES ACRS REGION. WITH LGT WINDS AND DECENT RADIATIONAL COOLING CONDITIONS SETTING UP...COULD BE ANOTHER FAVORABLE SETUP FOR FOG DVLPMNT LATE SUN NIGHT INTO MON MRNG. TEMPS...BOTH 12Z GFS AND NAM CAME IN COOLER WITH BNDRY LYR THICKNESSES THRU SHORT TERM...AND WITH 850 TEMPS. AS A RESULT... GENERALLY LOWERED TEMPS A FEW DEG FOR ALL THREE PERIODS. THIS LINED UP CLOSELY WITH MET GUID. RYAN LONG TERM /MONDAY THROUGH SATURDAY/... 500 MB FLOW FOR THE EXTENDED WILL BE WEST TO NORTHWEST...WHICH WILL KEEP DEEP TROPICAL/SUBTROPICAL MOISTURE TO OUR SOUTH. AT THE SURFACE HIGH PRESSURE WILL DOMINATE WITH ONLY TWO EXCEPTIONS. WILL KEEP MENTION OF PRECIP ACROSS FAR SOUTH MONDAY NIGHT AS BOTH NAM AND GFS BRING WAVE THROUGH KENTUCKY. BUT HAVE PULLED PRECIP OUT OF THE FAR SOUTH ON MONDAY AS THE EVOLUTION IS SLOWER WITH THIS RUN. MODELS HAVE BEEN SLIDING THIS WAVE A BIT FARTHER SOUTH...BUT DON'T FEEL GOOD ABOUT TAKING IT OUT OF MONDAY NIGHT. THE SECOND EXCEPTION IS A WEAK COLD FRONT WHICH WILL GO THROUGH TUESDAY NIGHT INTO WEDNESDAY. WILL KEEP THIS DRY BECAUSE OF TIMING OF FROPA AND STRENGTH...BUT WILL MONITOR THESE FACTORS FOR POSSIBLE INCLUSION IN THE NEXT PACKAGE. TEMPS WILL GENERALLY BE CLOSE TO NORMAL. TIPTON AVIATION /18Z-18Z/... CONDITIONS HAVE IMPROVED TO VFR. DO NOT EXPECT CONVECTION AT TAF SITES WITH AXIS OF INSTABILITY EAST OF THE AREA. DO PREDICT THAT MIST AND FOG WILL FORM TONIGHT WITH MODELS SHOWING PERSISTENT LOW LEVEL MOISTURE IN THE VICINITY OF A SECONDARY FRONT. MAINLY VFR CONDITIONS WILL RETURN ON SUNDAY IN THE DRYING NORTHERLY FLOW BEHIND THE FRONT. THE EXCEPTION MAY BE AT DAY...WHERE MODEL SOUNDINGS INDICATE MORE PERSISTENT BOUNDARY LAYER MOISTURE. CONIGLIO && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 326 PM EDT SAT AUG 19 2006 .SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/... FRNTL BNDRY PROGGED FAIRLY CLOSE TO I-71 ATTM. MAIN CONVECTION HAS FIRED AHEAD OF MID LVL S/WV IN AREA OF PVA WITH HIGHER AMOUNTS OF INSTABILITY. THESE TSTMS DVLPD ACRS SOUTH CNTRL OH AND NRN KY AND HAVE ALREADY PUSHED EAST OUT OF FCST AREA. IN WAKE OF THIS ACTIVITY...ISOLD -SHRA HAVE DVLPD RIGHT ALONG THE BNDRY FROM NEAR CMH METRO TO JUST WEST OF KILN. DO NOT EXPECT ANYTHING MORE THAN ISOLD CONVECTION AS FRNTL BNDRY TRACKS EAST ACRS REGION OVER NEXT FEW HOURS...AS BETTER PVA ALIGNED WITH CONVECTION TO EAST AND MODEL SOUNDINGS INDCG DVLP CAP AROUND 7KFT. TEMPS WERE IN THE 80S THIS AFTN. USED 18Z RUC FOR ERLY PORTION OF FCST. MID LVL S/WV AND VORT SHOULD BE EAST OF FCST AREA BY 22Z WITH STRONG NVA CURRENTLY ACRS INDIANA POISED TO MOVE ACRS REGION. HAVE MAINTAINED 20-30 POPS ALONG AND EAST OF I-71 INTO ERLY EVNG...THEN MAINTAIN LO CHC POPS ACRS SRN 1/2 FCST AREA INTO OVERNIGHT. FRNTL BNDRY WILL SAG SOUTH OF OHIO RIVER SLOWLY OVERNIGHT. SECONDARY BNDRY CURRENTLY OVER WESTERN GRT LKS WILL DROP SOUTH INTO FCST AREA LATE TONIGHT. FCST AREA AGAIN APPEARS TO NOT BE IN VERY FAVORABLE SITUATION FOR PCPN. FCST AREA WILL BE SPLIT BY TWO MAIN VORTS ASSOCD WITH MID LVL S/WV. ONE VORT WILL PASS WELL TO NORTH OF REGION ACRS SRN ONTARIO...WHILE SECOND VORT DROPS SE FROM MID MISSISSIPPI VLY INTO CNTRL KY BY ERLY SUN. SOME WEAK INSTABILITY AND LO LVL CONV NOTED WITH THE SECOND VORT DROPPING INTO KY...AND THIS MAY BE ENUF TO EITHER SPARK A FEW ISOLD SHRA/TSTMS LATE TONIGHT ACRS SRN FCST AREA...OR TSTMS THAT DVLP TO WEST OF REGION MAY CLIP SRN PORTIONS OF FCST AREA AFT MIDNIGHT. WITH THIS IN MIND...WILL MAINTAIN A 20 POP LATE TONIGHT ACRS SRN 1/2 FCST AREA. WITH ABUNDANT LO LVL MOISTURE ACRS REGION...POTENTIAL EXISTS FOR PATCHY FOG LATE TONIGHT AND INTO ERLY SUN. BOTH 12Z NAM AND GFS NOW A LITTLE QUICKER IN PUSHING S/WV EAST OF REGION ON SUN WITH SFC HI PRES AND DRIER AIRMASS BUILDING IN FROM NW. MODEL SOUNDINGS INDCG MID LVL CAP WILL STRENGTHEN DURING DAY SUN AS HI BUUILDS INTO REGION. WITH FRNTL BNDRY SAGGING INTO UPR TN VLY BY SUN AFTN/EVNG...THINKING MOST LOCATIONS WILL BE DRY THROUGHOUT DAY SUNDAY. THERE IS AN OUTSIDE CHANCE AT A -SHRA OR TWO ALONG AND SOUTH OF OHIO RIVER DURING AFTN HOURS...BUT CHANCE IS LOW ENUF TO KEEP MENTION OUT OF FCST ATTM. EXPECTING PTLY CLDY SKIES AS CU RULE AND MODEL SOUNDINGS SUGGESTING SCT/BKN CU DVLPG AS 850 CAA EXPANDS SOUTH WITH HI PRES. SKIES SHOULD BECOME MSTLY CLR SUN NIGHT AS CENTER OF SFC HI MOVES ACRS REGION. WITH LGT WINDS AND DECENT RADIATIONAL COOLING CONDITIONS SETTING UP...COULD BE ANOTHER FAVORABLE SETUP FOR FOG DVLPMNT LATE SUN NIGHT INTO MON MRNG. TEMPS...BOTH 12Z GFS AND NAM CAME IN COOLER WITH BNDRY LYR THICKNESSES THRU SHORT TERM...AND WITH 850 TEMPS. AS A RESULT... GENERALLY LOWERED TEMPS A FEW DEG FOR ALL THREE PERIODS. THIS LINED UP CLOSELY WITH MET GUID. RYAN && .LONG TERM /MONDAY THROUGH SATURDAY/... 500 MB FLOW FOR THE EXTENDED WILL BE WEST TO NORTHWEST...WHICH WILL KEEP DEEP TROPICAL/SUBTROPICAL MOISTURE TO OUR SOUTH. AT THE SURFACE HIGH PRESSURE WILL DOMINATE WITH ONLY TWO EXCEPTIONS. WILL KEEP MENTION OF PRECIP ACROSS FAR SOUTH MONDAY NIGHT AS BOTH NAM AND GFS BRING WAVE THROUGH KENTUCKY. BUT HAVE PULLED PRECIP OUT OF THE FAR SOUTH ON MONDAY AS THE EVOLUTION IS SLOWER WITH THIS RUN. MODELS HAVE BEEN SLIDING THIS WAVE A BIT FARTHER SOUTH...BUT DON'T FEEL GOOD ABOUT TAKING IT OUT OF MONDAY NIGHT. THE SECOND EXCEPTION IS A WEAK COLD FRONT WHICH WILL GO THROUGH TUESDAY NIGHT INTO WEDNESDAY. WILL KEEP THIS DRY BECAUSE OF TIMING OF FROPA AND STRENGTH...BUT WILL MONITOR THESE FACTORS FOR POSSIBLE INCLUSION IN THE NEXT PACKAGE. TEMPS WILL GENERALLY BE CLOSE TO NORMAL. TIPTON && .AVIATION /18Z-18Z/... CONDITIONS HAVE IMPROVED TO VFR. DO NOT EXPECT CONVECTION AT TAF SITES WITH AXIS OF INSTABILITY EAST OF THE AREA. DO PREDICT THAT MIST AND FOG WILL FORM TONIGHT WITH MODELS SHOWING PERSISTENT LOW LEVEL MOISTURE IN THE VICINITY OF A SECONDARY FRONT. MAINLY VFR CONDITIONS WILL RETURN ON SUNDAY IN THE DRYING NORTHERLY FLOW BEHIND THE FRONT. THE EXCEPTION MAY BE AT DAY...WHERE MODEL SOUNDINGS INDICATE MORE PERSISTENT BOUNDARY LAYER MOISTURE. CONIGLIO && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ oh AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 808 PM MDT SAT AUG 19 2006 .DISCUSSION...THE BASIC FORECAST LOOKS ON TRACK. SOME THUNDERSTORMS HAVE DEVELOPED OVER A NARROW MOISTURE/CAPE AXIS ACROSS NORTHEASTERN WY...AND A FEW OF THESE HAVE BECOME LEFT-MOVING SUPERCELLS. THESE ARE EXPECTED TO WEAKEN AS THEY CONTINUE NORTHEAST WHERE CAPE IS < 100 J/KG. HOWEVER...THE RUC IS SUGGESTING THAT A LOW-LEVEL JET WILL DEVELOP BY 06Z ACROSS WRN SD...WITH THETA-E DECENT ADVECTION AND ELEVATED CAPE OF 200-500 J/KG. THUS...THE FORECAST MAY NEED TO BE UPDATED FOR THUNDERSTORMS AFTER 06Z IF PROFILER AND VWP OBSERVATIONS SUPPORT THE MODEL FORECAST OF THE LOW-LEVEL JET. && UNR...WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ BUNKERS sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 734 PM EDT SAT AUG 19 2006 .SHORT TERM /REST OF TONIGHT/... HAVE ISSUED A COUPLE OF UPDATES ALREADY THIS EVENING...TO TRACK THE PROGRESS OF THE PRIMARY BATCH OF PRECIP ACROSS THE CWA. ANOTHER ROUND...ALBEIT MUCH THINNER IS TRACKING ACROSS SE OHIO...ASSOCIATED WITH THE COLD FRONT. AFTER THIS NEXT LINE TRACKS THROUGH DEW POINTS SHOULD BE ABLE TO FALL A COUPLE OF NOTCHES. GOOD CLEARING WILL OCCUR DURING SUNDAY AFTERNOON. HOWEVER...SIGNIFICANT COOLING IS NOT EXPECTED. WE WILL STILL BE ABLE TO FALL BACK ABOUT 5 DEGREES...TO NEAR NORMAL HIGH TEMPS FOR TOMORROW. THE MAIN CHANGES FOR THIS UPDATE WERE TO CONTINUE TO SLIDE THE BEST CHANCE OF POPS TO OUR EAST...AND TRY TO TIME THE THIN LINE ACROSS THE AREA. COOLED HTS OVERNIGHT LOW A COUPLE OF DEGREES...AND ROSE EKN A COUPLE. FEW OTHER CHANGES WERE MADE. WILL LIKELY ISSUE ANOTHER UPDATE TO THE ZFP ONE MOST OF THE PRECIP EXITS...TO FRESHEN UP THE WORDING. && .AVIATION... CEILINGS REMAIN VFR AT ALL OF THE TAF SITES AT 23Z...WITH VIS BRINGING THEM DOWN TO MVFR AT BOTH BKW AND HTS. MOST LOCATIONS SHOULD FALL TO MVFR OR IFR WITH FOG PRIOR TO DAWN...WITH A SLOW CLIMB IN CEILING HEIGHT THROUGH THE LATE MORNING HOURS. WILL CONTINUE TO TWEAK THIS FORECAST...GIVEN SEVERAL BREAKS IN THE CLOUD COVER UPSTREAM. WITH THE LOW CHANCE OF PRECIP...MAINLY LESS THAN 40 PERCENT OVER THE NEXT 24 HOURS...HAVE OPTED TO LEAVE MOST OF IT OUT UNTIL WE GET A BETTER HANDLE ON LOCATION AND INTENSITY...PARTICULARLY ACROSS THE SE CORNER OF THE AREA...FOR BKW AS ANOTHER WAVE OF ENERGY SLIDES ACROSS AND ALONG THE FRONT TOMORROW AFTERNOON. && .PREV DISCUSSION... /ISSUED 259 PM EDT SAT AUG 19 2006/ SHORT TERM /REST OF TONIGHT THROUGH TUESDAY/... NEW MODEL RUNS CONSISTENT WITH PREVIOUS RUNS PUSHING FRONT THROUGH AND TO THE SOUTH. WAVE ALONG FRONT KEEPS CHC ACROSS SOUTH. NO REAL CHANGE TO FCST. LOCAL WRF AND RUC MODEL IDENTIFIED CONVECTION SETTING UP THIS AFTERNOON WELL BELOW UPPER LEVEL DIVERGENCE. AFTER SUNSET THEY SHOW THINGS CALMING DOWN AS UPPER DIVERGENCE MOVES OFF TO THE EAST. AVIATION... A FAIR AMOUNT OF MOISTURE AROUND TONIGHT SHOULD KEEP SOME CLOUDS AROUND. BUT...WITH PRECIP THIS AFTERNOON AND THE FRONT ONLY TO NEAR OHIO RIVER SUNDAY MORNING...FOG SHOULD SET UP IN NORMAL PRIME AREAS. WITH MOISTURE AND SOME CLOUDS HAVE RESTRICTED LOWER CONDITIONS MORE TO VSBY THEN CIG. PREV DISCUSSION... /ISSUED 1247 PM EDT SAT AUG 19 2006/ LONG TERM /TUESDAY THROUGH SATURDAY/... MODELS ARE SHOWING PRIMARY AND SECONDARY FRONTAL PLACEMENTS IN SIMILAR LOCATIONS COMPARED WITH PREVIOUS RUNS. MAINTAINED TUESDAY POPS IN SOUTHERN ZONES WITH PRIMARY FRONT SLOWLY SINKING SOUTH. HOWEVER...THE SECONDARY FRONT CONTINUES TO LOOK MORE DIFFUSE AND MOISTURE STARVED WITH EACH SUCCESSIVE MODEL RUN. I REMOVED THE SLIGHT CHANCE POPS FOR WEDNESDAY/WEDNESDAY NIGHT. LOOKS LIKE A COMFORTABLE PERIOD THURSDAY INTO FRIDAY...WITH DRY AIR MASS AND SURFACE HIGH PRESSURE PASSING JUST TO OUR NORTH. AS THE HIGH GOES OVER THE ATLANTIC LATE FRIDAY THROUGH NEXT WEEKEND...MOISTURE LOOKS TO RETURN AT LOW LEVELS...WHILE UPPER LEVEL TROUGHINESS ARRIVES FROM THE WEST. CHANCE POPS HAVE BEEN INTRODUCED FOR THIS TIME PERIOD. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SHORT TERM...KF AVIATION...KF wv AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 259 PM EDT SAT AUG 19 2006 .SHORT TERM /REST OF TONIGHT THROUGH TUESDAY/... NEW MODEL RUNS CONSISTENT WITH PREVIOUS RUNS PUSHING FRONT THROUGH AND TO THE SOUTH. WAVE ALONG FRONT KEEPS CHC ACROSS SOUTH. NO REAL CHANGE TO FCST. LOCAL WRF AND RUC MODEL IDENTIFIED CONVECTION SETTING UP THIS AFTERNOON WELL BELOW UPPER LEVEL DIVERGENCE. AFTER SUNSET THEY SHOW THINGS CALMING DOWN AS UPPER DIVERGENCE MOVES OFF TO THE EAST && .AVIATION... A FAIR AMOUNT OF MOISTURE AROUND TONIGHT SHOULD KEEP SOME CLOUDS AROUND. BUT...WITH PRECIP THIS AFTERNOON AND THE FRONT ONLY TO NEAR OHIO RIVER SUNDAY MORNING...FOG SHOULD SET UP IN NORMAL PRIME AREAS. WITH MOISTURE AND SOME CLOUDS HAVE RESTRICTED LOWER CONDITIONS MORE TO VSBY THEN CIG. && .PREV DISCUSSION... /ISSUED 1247 PM EDT SAT AUG 19 2006/ LONG TERM /TUESDAY THROUGH SATURDAY/... MODELS ARE SHOWING PRIMARY AND SECONDARY FRONTAL PLACEMENTS IN SIMILAR LOCATIONS COMPARED WITH PREVIOUS RUNS. MAINTAINED TUESDAY POPS IN SOUTHERN ZONES WITH PRIMARY FRONT SLOWLY SINKING SOUTH. HOWEVER...THE SECONDARY FRONT CONTINUES TO LOOK MORE DIFFUSE AND MOISTURE STARVED WITH EACH SUCCESSIVE MODEL RUN. I REMOVED THE SLIGHT CHANCE POPS FOR WEDNESDAY/WEDNESDAY NIGHT. LOOKS LIKE A COMFORTABLE PERIOD THURSDAY INTO FRIDAY...WITH DRY AIR MASS AND SURFACE HIGH PRESSURE PASSING JUST TO OUR NORTH. AS THE HIGH GOES OVER THE ATLANTIC LATE FRIDAY THROUGH NEXT WEEKEND...MOISTURE LOOKS TO RETURN AT LOW LEVELS...WHILE UPPER LEVEL TROUGHINESS ARRIVES FROM THE WEST. CHANCE POPS HAVE BEEN INTRODUCED FOR THIS TIME PERIOD. PREV DISCUSSION... /ISSUED 654 AM EDT SAT AUG 19 2006/ AVIATION... FOG AT HTS WILL BURN OFF BY 13Z...THEN WE WILL BE WATCHING FOR SHWRS AND TSTORMS DEVELOPING AHEAD A FRONT MOVING THROUGH THE OHIO VALLEY AS HIGH PRESSURE DEPARTS. THINKING SHOWERS AND STORMS WILL BE MOST NUMEROUS THROUGH NORTHERN TERMINALS PKB AND CKB. ALTHOUGH STORMS WILL BE SCATTERED AND HARD TO PINPOINT EXACT TIME...DID CODE AT LEAST CB OR TSRA IN ALL TERMINALS. WILL BE HOLDING OFF ON FOG FOR MOST SPOTS TONIGHT WITH CLOUDS HANGING AROUND...BUT ENOUGH BREAKS SHOULD OCCUR ACROSS THE NORTH FOR IFR FOG TO FORM. PREV DISCUSSION... /ISSUED 411 AM EDT SAT AUG 19 2006/ SHORT TERM /TODAY THROUGH SATURDAY NIGHT/... WILL NEED SOME SUNSHINE OR AN OUTFLOW BOUNDARY TODAY TO GET CONVECTION GOING PERHAPS IN THE CENTRAL AND SOUTH BEFORE SHORTWAVE CUTS THROUGH THE OHIO VALLEY LATER THIS AFTERNOON. DID RAISE HIGHS CLOSER TO GUIDANCE IN THE SOUTH...THINKING THAT SUNSHINE WILL BREAK THROUGH THERE AT TIMES. BUFKIT SOUNDINGS SHOW A DECENT AMOUNT OF CINH IN THE CENTRAL AND SOUTH...WITH LESS ACROSS NORTHERN WEST VIRGINIA AND SOUTHEASTERN OHIO. THEREFORE...KEPT POPS PRETTY MUCH AS IS...AND STUCK WITH LIKELIES ACROSS FAR NORTH AND SOUTHEAST OHIO. ALSO DELAYED POPS BY ABOUT 3HRS WITH SLOWER PROGRESSION OF SHRTWV AND BOUNDARY. WILL BE INTERESTED TO SEE PWATS OFF OF 12Z SOUNDINGS...WITH 70F DEWPOINTS...SMALL MBE VELOCITIES...GOOD H850 DEWS AND WARM CLOUD LAYER TO 13KFT...DID FLIRT WITH ADDING HEAVY RAINFALL WORDING WITH LIKELY POPS TO ZONES...BUT WILL LET NEXT SHIFT MAKE THAT DECISION. SPC IS INTERESTED IN NORTHERN WEST VIRGINIA AND SOUTHEASTERN OHIO FOR POSSIBLE STRONG STORMS THIS AFTERNOON. OVER THE PAST FEW RUNS...THE NAM HAS BEEN HINTING AT CONVECTION ONGOING IN THE SOUTH OVERNIGHT SATURDAY CLOSER TO THE COLD FRONT...AS THE FRONT BECOMES MORE STRETCHED WEST TO EAST AND SLOWS. WITH BIG 0-6KM SHEAR VALUES OF 50 M/S DURING THE OVERNIGHT AND THICKNESS DIVERGENCE OVER SOUTHERN WEST VIRGINIA...DID HOLD ONTO POPS A LITTLE BIT LONGER ACROSS SOUTHERN COUNTIES...ESPECIALLY IF BOUNDARY BECOMES STATIONARY. A SIMILAR SETUP PRODUCED A NICE COMPLEX IN THE MISSISSIPPI VALLEY LAST NIGHT. IF THIS DOES DEVELOP...IT MAY BE ABLE TO HOLD TOGETHER THROUGH THE OHIO VALLEY WITH THAT AMOUNT OF SHEAR. CLOCKWISE HODOGRAPH POINTS MORE TO A SOUTHEASTERLY MOVEMENT. FRONT SHOULD MAKE ENOUGH PROGRESS THOUGH TO BRING PRECIP TO AN END IN THE NORTH LATER TONIGHT. DID DECREASE CLOUD COVER THERE BY SUNDAY MORNING. LONG TERM /SUNDAY THROUGH SATURDAY/... SHEAR VALUES START TO DECREASE BY SUNDAY MORNING BUT THERE MAY BE ONE LAST OPPORTUNITY FOR THUNDERSTORMS SUNDAY LATE MORNING AND MIDDAY EASTERN AND FAR SOUTHERN PORTIONS OF AREA IN THE DAYTIME HEATING BEFORE FRONT AND UPPER SHORT WAVE FINALLY PUSH ON THROUGH. DRIER AIR FILTERS IN FROM THE NORTH FOR SUNDAY NIGHT AND MONDAY AS HIGH PRESSURE BUILDS E ACROSS LOWER GREAT LAKES. MODELS APPEAR TO CONCUR ON IDEA OF WAVE ALONG FRONT...BRINGING PRECIPITATION BACK INTO AT LEAST SOUTHERN PORTION OF AREA LATE MONDAY AND CONTINUING INTO TUESDAY. THERE ARE DIFFERENCES W/R TIMING AND HOW FAR N FORCING AND PRECIPITATION GET. PLAYED IT CONSERVATIVE W/R HOW FAR N PRECIPITATION GETS...AND RAISED POPS S ONLY SLIGHTLY WHILE ALSO SPEEDING UP ONSET A BIT...ALL IN COORD WITH ADJACENT OFFICES. NEW COLD FRONT PUSHES THROUGH LATE WEDNESDAY INTO THURSDAY FOLLOWED BY MORE DRY...COOL AIR. EDGED POPS DOWN A BIT AS THIS ONE LOOKS MOISTURE STARVED WITH LITTLE INSTABILITY. EDGED HIGH TEMPERATURES UP SUNDAY ACROSS THE N IN THE SUNSHINE AS WAS NOT IMPRESSED WITH LOW LEVEL THERMAL GRADIENT BEHIND FRONT. ENDED UP CLOSEST TO THE HIGHER NUMBERS N AND THE LOWER NUMBERS S WHERE CLEARING IS LATER. NUMBERS WERE BETTER CONVERGED FOR SUNDAY NIGHT AND MONDAY SO STAYED CLOSE. LITTLE CHANGE MADE BEYOND MONDAY. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SHORT TERM...ARJ AVIATION...AAR wv AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON KY 430 AM EDT SUN AUG 20 2006 .DISCUSSION... COLD FRONT HAS DROPPED INTO THE NORTHERN PORTIONS OF OUR CWA THIS MORNING. A THIN LINE OF SCATTERED SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ALONG THE BOUNDARY...WITH A FEW ADDITIONAL POCKETS OF SHOWER AND THUNDERSTORMS OUT AHEAD OF THE FRONT. OTHERWISE...AN MCS WAS TRACKING EASTWARD THROUGH WESTERN KENTUCKY. EXPECT THIS FEATURE TO WEAKEN SOME AS IT PROGRESSES EASTWARD INTO A MORE STABLE ENVIRONMENT AND WHERE THE ATMOSPHERE HAS BEEN WORKED OVER DURING THE OVERNIGHT. RUC ANALYSIS AND RADAR CONFIRMS THIS TREND. EXPECT SHOWERS AND THUNDERSTORMS TO CONTINUE TO DEVELOP ALONG AND AHEAD OF THE FRONT AS IT SLIDES SOUTHWARD THROUGH THE DAY. ACTIVITY WILL INTENSIFY IN COVERAGE AND STRENGTH LATER IN THE AFTERNOON WITH HELP OF DAY TIME HEATING AND AS SOME SHORT WAVE ENERGY MANAGES TO MAKE ITS WAY INTO THE AREA. PERSISTENCE WOULD SUGGEST THAT ONE OR TWO STORMS MAY EVEN MAKE IT TO SEVERE LEVELS THIS AFTERNOON WITH THE MAIN THREAT BEING HIGH WINDS. ALSO...SOME LOCALLY HEAVY RAINFALL WILL BE POSSIBLE. WILL MENTION THESE IN THE HWO. WILL SEE A BRIEF REPRIEVE FROM SHOWER ACTIVITY LATER TONIGHT. AFTERWARDS...MODELS STILL DEVELOP A WAVE OF LOW PRESSURE AND TRACK IT EASTWARD BETWEEN THE TN AND OH VALLEYS LATE MONDAY INTO TUESDAY. NAM IS FURTHER SOUTH AND FASTER WITH ANY ENERGY ASSOCIATED WITH THIS DISTURBANCE AS COMPARED TO THE GFS. FOR NOW STAYED WITH THE MORE CONSISTENT GFS SOLUTION. BEST LIFT OVER EASTERN KENTUCKY APPEARS TO OCCUR DURING THE MONDAY NIGHT...TUESDAY TIME FRAME. SO HIT POPS HARDEST DURING THIS PERIOD. && .PREV DISCUSSION... 930 PM EDT SAT AUG 19 2006 S/WV HAS MOVED THRU THE AREA AND MOST OF THE CONVECTION NOW EAST/SOUTH OF CWFA. ISOLATED CONVECTION POPPING UP IN CNTRL KY BUT DIMINISHES TO BARELY -RA BY THE TIME IT GETS TO I-75. WX OF GREATEST CONCERN IS THE SHRA ALONG THE QUASI-STATIONARY FNT FM PMH TO CVG AND CONVECTIVE COMPLEX ON THE WRN FRINGE OF CNTRL KY CWFA. HAVE KEPT CHC POP IN NORTH FOR FNTL CONVECTION AND FEEL THE MCS IN WRN KY WILL HOLD AT BAY UNTIL AFTER SUNRISE. LOCALLY DENSE FOG IN VLYS IS SPILLING ONTO RIDGES IN LIGHT SRLY BREEZE. LIGHT WIND SHOULD GO CALM TONITE AND FOG WILL SETTLE BUT THE DEPTH OF THE MOIST/SATURATED AIR MAY PRECLUDE ANY SIGNIFICANT DROP IN TEMP. ALREADY INTO THE LOWER 70S AND HAVE PROJECTED LOWS IN THE NRN 2/3 CWFA TO ONLY DROP A COUPLE OF DEG FROM CURRENT TEMPS...PUTTING THEM BARELY INTO THE UPPER 60S. 536 PM EDT SAT AUG 19 2006 SW/V IS MOVING FROM THE OH VALLEY AND INTO THE CENTRAL APPALACHIANS LATE THIS AFTERNOON. UPPER TROUGH WAS MOVING FROM THE UPPER MIDWEST AND INTO THE GREAT LAKES. MCS DEVELOPED OVER THE CWA AHEAD OF THE SW/V AND MAINLY PRODUCED LOCALLY HEAVY RAIN OF AN INCH TO AN INCH AND ONE HALF IN ABOUT ONE HALF OF AN HOUR. STRATIFORM RAIN LINGERS OVER THE EASTERN 2/3 OF THE CWA...WITH ONLY A COUPLE OF POCKETS OF INSTABILITY LEFT NEAR THE VA AND TN BORDERS. AT THE SFC...AN AREA OF LOW PRESSURE WAS OVER EASTERN LAKE ERIE...WITH A COLD FRONT TRAILING SW TO NEAR KCMH TO KILN TO KHNB TO NEAR KMVN AND THEN WAS STATIONARY DOWN INTO WESTERN TX. THE INITIAL SW/V SHOULD PASS EAST OF THE EVENING...WITH SW/V RIDGING WORKING ACROSS THE REGION DURING THE EVENING...LEADING TO A LULL IN THE CONVECTION. WE EXPECT FOG DEVELOPMENT WHERE ANY HOLES IN THE CLOUDS ARE PRESENT. THE SFC COLD FRONT WILL GRADUALLY SAG INTO THE NORTHERN PART OF THE CWA BY 12 SUN. HOWEVER...EXPECT VERY LITTLE CONVECTION OVERNIGHT IN THE CWA...WITH SOME POSSIBLY FORMING TO OUR WEST VERY LATE AS THE TROUGH AXIS APPROACHES. THE TROUGH AXIS CROSS THE AREA DURING THE DAY AND MODEL CONSENSUS IS THAT CONVECTION WILL FROM IN THE MID TO LATE MORNING AND MOVE TO THE SOUTH OF THE CWA DURING THE EVENING AS THE FRONT CONTINUES TO MOVE SOUTH AND BE MORE WIDESPREAD OVER THE SW 2/3 OF THE CWA IN WARMER AND SLIGHTLY MORE MOIST AIRMASS OUT AHEAD OF THE FRONT AND WENT LIKELY THERE FOR SUN. LOW TEMPS TONIGHT WERE TRICKY...WITH TEMPS ALREADY NEAR MOS GUIDANCE LOWS IN THE RAIN COOLED AIR. MOS NUMBERS WERE CLOSE AND WENT WITH A BLEND OVERALL AND CLOSE TO THE PREVIOUS FORECAST. FOG COULD DRIVE TEMPS DOWN FURTHER...AND LATER SHIFTS WILL MONITOR. TEMPS ON SUN WILL ALSO BE TRICKY...AND HIGHLY DEPENDENT ON PRECIP AND FROPA TIMING. OVERALL TRENDED TEMPS DOWN ON SUN. MODELS CONTINUE TO INDICATE THAT THE FRONT WILL GET HUNG UP OVER THE TN VALLEY. AS ANOTHER SW/V DROPS SOUTH AND SHARPENS THE BROAD EASTERN TROUGH THAT WILL BE IN PLACE EARLY IN THE WEEK. A COUPLE OF SFC WAVES ARE EXPECTED TO TRACK NE ALONG THE BOUNDARY. CONTINUED UPWARD TREND OF POPS WITH MORE RUN TO RUN CONSISTENCY WITH THIS IDEA...MAINLY ON MON NIGHT AND DURING THE DAY ON TUE...WHEN BEST UVV IS INDICATED OVER THE AREA. EXTENDED (OZ WED THROUGH 12Z SUN)...ONLY A FEW SLIGHT CHANGES MADE TO EXTENDED PORTION OF FORECAST. LATEST GFS HAS AN MORE DIFFUSE FRONT MOVING SOUTH ACROSS THE OHIO VALLEY WEDNESDAY NIGHT INTO THURSDAY. IN FACT...IT IS VERY DIFFICULT TO EVEN FIND THE FRONT IN THE MODEL DATA. MODEL CROSS SECTIONS WITH A VERY SHALLOW LAYER OF MOIST AIR NEAR THE SURFACE PRETTY MUCH THE WHOLE WEEK. THIS WARRANTED LEAVING IN PARTLY TO MOSTLY CLOUDY SKIES...BUT DEFINITELY NOT PRECIPITATION. REMOVED PRECIPITATION CHANCES FROM THE FORECAST THROUGH NEXT FRIDAY. GFS AND ECMWF BOTH TRYING TO MOVE A FRONTAL WAVE UP THE EAST COAST...JUST TO THE EAST OF THE APPALACHIAN MOUNTAINS NEXT SATURDAY...SO DECIDED TO ADD POPS TO THAT PORTION OF THE FORECAST. MADE CORRESPONDING ADJUSTMENTS TO QPF...SKY...AND WEATHER GRIDS FOR NEXT SATURDAY AS WELL. TEMPERATURES LOOKED PRETTY GOOD AS WELL. DECIDED TO INCREASE DAYTIME HIGHS BY A DEGREE OR SO ACROSS THE BOARD...AS MEXMOS NUMBERS HAVE COME IN A BIT HIGHER EACH OF THE PREVIOUS 3 RUNS. A FEW TWEAKS WERE ALSO MADE TO DEWPOINTS...AS LATE IN THE WEEK THEY SEEMED A BIT HIGH. WINDS WERE IN GOOD SHAPE AND WERE LEFT ALONE. 1224 PM EDT SAT AUG 19 2006 ISSUED AN UPDATE EARLIER TO MAINLY REMOVE MORNING FOG REFERENCES. A SW/V WAS MOVING THROUGH THE OH VALLEY THIS AFTERNOON AND SHOULD BE CROSSING THE REGION NEAR PEAK HEATING. CONVECTION HAS DEVELOPED OVER THE BLUEGRASS ASSOCIATED WITH THIS FEATURE. AN ISOLATED THUNDERSTORM HAS DEVELOPED NEAR THE TN LINE. MODEL FORECAST SOUNDINGS INDICATE THAT MODERATE INSTABILITY WILL DEVELOP ACROSS THE CWA TODAY...WITH CAPES AROUND 2500 TO 3000 J/KG AND LI AROUND -6 EXPECTED. WIND FIELDS ARE WEAK AND WBZ HEIGHTS ARE EXPECTED TO BE IN THE 14 TO 15K FT RANGE. EXPECT THIS CONVECTION TO PROGRESS EAST INTO THE CWA BETWEEN 17 AND 18Z...GENERALLY BETWEEN I 64 AND THE HAL RODGERS PARKWAY. ADDITIONAL CONVECTION SHOULD DEVELOP AS CONVECTIVE TEMPS ARE REACHED OUTSIDE OF THIS AREA. MAIN FEATURE OF AFTERNOON CONVECTION SHOULD BE LOCALLY HEAVY RAIN...THOUGH SOME OF THE STRONGEST STORMS...IF THEY CAN BUILD ABOVE THE TROPOPAUSE...COULD PRODUCE AN ISOLATED MICROBURST OR TWO. OVERALL...KEPT POPS NEAR THE PREVIOUS FORECAST. RAISED TEMPS ONE OR TWO DEGREES IN SOME AREAS BASED ON THE LATEST TRENDS. && .JKL WATCHES/WARNINGS/ADVISORIES...NONE. && $$ RAY ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 355 AM CDT SUN AUG 20 2006 .DISCUSSION... WEAK AND DIFFUSE COLD FRONT LOOKS TO HAVE PASSED COMPLETELY THROUGH THE AREA...AND SOMEWHAT DRIER AIR IS SLOWLY WORKING ITS WAY SOUTH OUT OF THE UPPER MID-WEST THIS MORNING. STILL HAVING TO DEAL WITH ISOLATED SHOWERS AND THUNDERSTORMS THIS MORNING...MAINLY SOUTH OF THE I-70 CORRIDOR. ADDITIONALLY...FOG AND STRATUS HAVE DEVELOPED/ARE DEVELOPING ACROSS MUCH OF THE CWFA THIS MORNING. BOTH THE RUC AND NAM ARE SHOWING SOME MOISTURE CONVERGENCE ON WHAT APPEARS TO BE THE 850MB FRONT STRETCHING FROM NEAR KSTL TO JUST NORTH OF KSGF WHICH APPEARS TO BE THE PRIMARY CAUSE OF OUR SHOWER ACTIVITY. THIS MOISTURE CONVERGENCE REALLY TRENDS DOWNWARD AFTER SUNRISE AS THE 850 FRONT DROPS SOUTHWARD SO I WOULD EXPECT THE SHOWERS TO DIMINISH BY MID-MORNING IF NOT SOONER. FOG AND STRATUS SHOULD LIFT BY MID MORNING INTO A BROKEN STRATO-CU/CUMULUS FIELD...AND IT APPEARS THAT SHORTWAVE ENERGY EJECTING EASTWARD ACROSS MISSOURI FROM THE PLAINS COMBINED WITH DIFFERENTIAL HEATING NEAR THE FRONTAL BOUNDARY WILL ALLOW MORE SHOWERS AND THUNDERSTORMS TO GET FIRED UP ACROSS SOUTHERN MISSOURI BY LATE MORNING OR EARLY AFTERNOON. HAVE THEREFORE KEPT SLIGHT CHANCE ALONG THE I-70 CORRIDOR FADING INTO 40 AND 50 PERCENT CHANCE OF PRECIP DOWN ACROSS THE SOUTHERN CWFA GOING IN THE FORECAST TODAY. REMAINDER OF THE SHORT TERM SEES THE FRONT CONTINUE TO SAG SLOWLY SOUTHWARD INTO NORTHERN ARKANSAS...AND FINALLY THRU ARKANSAS INTO LOUISIANA BY TUESDAY EVENING. FLOW BECOMES MORE NORTHWESTERLY ALOFT BRINGING WEAK SHORTWAVES ACROSS THE AREA JUST ABOUT EVERY PERIOD. LOW LEVEL MOISTURE DECREASES TO THE POINT WHERE CONVECTION SHOULDN'T BE MUCH OF A THREAT ANYWHERE EXCEPT ACROSS FAR SOUTHERN AREAS. HAVE KEPT SLIGHT TO LOW CHANCE POPS GOING THROUGH MONDAY NIGHT DOWN SOUTH TO COVER FOR THE ROGUE SHOWER OR STORM WHICH COULD RUMBLE THROUGH. HAVE GONE A COUPLE OF DEGREES WARMER THAN GUIDANCE THROUGH THE SHORT TERM AS VERIFICATION SHOWS THE MOS HAS BEEN RUNNING 2-3 DEGREES TOO COOL FOR THE PAST MONTH OR SO. CARNEY && .AVIATION... FOR THE 06Z TAFS...SCT SHRA AND TSRA CONT TO DVLP S AND E OF STL ATTM. MAY NEED TO MENTION VCTS IN STL OR SUS DURING THE FIRST COUPLE OF HRS OF THE FCST PERIOD DEPENDING ON LATEST RADAR TRENDS. MDL TIME SECTIONS INDICATE RH INCRSG TO 90 PERCENT AT 850 MB AND BLW LT TGT AND EARLY SUN MRNG. MOS GUIDANCE STILL HINTS AT STRATUS AND FOG DVLPG LTR TGT IN THE TAF SITES. UIN IS ALREADY DOWN TO 3 SM IN FOG. WILL CONT MENTION OF CLOUD CEILING BLW 2000 FT LT TGT AND EARLY SUN MRNG WITH AT LEAST LGT FOG AT THE TAF SITES. THIS FOG SHOULD DISSIPATE BY LT SUN MRNG WITH THE STRATUS LFTG AS WELL. WILL FCST CONDITIONS AT THE TAF SITES RETURNING TO VFR BY SUN AFTN. GKS && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 154 AM EDT SUN AUG 20 2006 .AVIATION /06Z-06Z/... A COLD FRONT HAS MOVED SE OF THE TERMINALS THIS MORNING. DESPITE MID CLOUDS BEHIND THE FRONT...MVFR WITH SOME IFR VISIBILITIES WILL DEVELOP AND PERSIST THROUGH 12Z-14Z. FCST SNDG PARAMETERS INDICATE THAT LOW ST MAY FORM AS WELL...ALTHOUGH THIS IS LOOKING LESS LIKELY. LIGHT AND VARIABLE WINDS WILL TURN LIGHT NE AS CLOUDS DECREASE NW TO SE AFTER 16Z. AFTER 01Z..EXPECT SKC. && PREV DISCUSSION... /ISSUED 326 PM EDT SAT AUG 19 2006/ SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/... FRNTL BNDRY PROGGED FAIRLY CLOSE TO I-71 ATTM. MAIN CONVECTION HAS FIRED AHEAD OF MID LVL S/WV IN AREA OF PVA WITH HIGHER AMOUNTS OF INSTABILITY. THESE TSTMS DVLPD ACRS SOUTH CNTRL OH AND NRN KY AND HAVE ALREADY PUSHED EAST OUT OF FCST AREA. IN WAKE OF THIS ACTIVITY...ISOLD -SHRA HAVE DVLPD RIGHT ALONG THE BNDRY FROM NEAR CMH METRO TO JUST WEST OF KILN. DO NOT EXPECT ANYTHING MORE THAN ISOLD CONVECTION AS FRNTL BNDRY TRACKS EAST ACRS REGION OVER NEXT FEW HOURS...AS BETTER PVA ALIGNED WITH CONVECTION TO EAST AND MODEL SOUNDINGS INDCG DVLP CAP AROUND 7KFT. TEMPS WERE IN THE 80S THIS AFTN. USED 18Z RUC FOR ERLY PORTION OF FCST. MID LVL S/WV AND VORT SHOULD BE EAST OF FCST AREA BY 22Z WITH STRONG NVA CURRENTLY ACRS INDIANA POISED TO MOVE ACRS REGION. HAVE MAINTAINED 20-30 POPS ALONG AND EAST OF I-71 INTO ERLY EVNG...THEN MAINTAIN LO CHC POPS ACRS SRN 1/2 FCST AREA INTO OVERNIGHT. FRNTL BNDRY WILL SAG SOUTH OF OHIO RIVER SLOWLY OVERNIGHT. SECONDARY BNDRY CURRENTLY OVER WESTERN GRT LKS WILL DROP SOUTH INTO FCST AREA LATE TONIGHT. FCST AREA AGAIN APPEARS TO NOT BE IN VERY FAVORABLE SITUATION FOR PCPN. FCST AREA WILL BE SPLIT BY TWO MAIN VORTS ASSOCD WITH MID LVL S/WV. ONE VORT WILL PASS WELL TO NORTH OF REGION ACRS SRN ONTARIO...WHILE SECOND VORT DROPS SE FROM MID MISSISSIPPI VLY INTO CNTRL KY BY ERLY SUN. SOME WEAK INSTABILITY AND LO LVL CONV NOTED WITH THE SECOND VORT DROPPING INTO KY...AND THIS MAY BE ENUF TO EITHER SPARK A FEW ISOLD SHRA/TSTMS LATE TONIGHT ACRS SRN FCST AREA...OR TSTMS THAT DVLP TO WEST OF REGION MAY CLIP SRN PORTIONS OF FCST AREA AFT MIDNIGHT. WITH THIS IN MIND...WILL MAINTAIN A 20 POP LATE TONIGHT ACRS SRN 1/2 FCST AREA. WITH ABUNDANT LO LVL MOISTURE ACRS REGION...POTENTIAL EXISTS FOR PATCHY FOG LATE TONIGHT AND INTO ERLY SUN. BOTH 12Z NAM AND GFS NOW A LITTLE QUICKER IN PUSHING S/WV EAST OF REGION ON SUN WITH SFC HI PRES AND DRIER AIRMASS BUILDING IN FROM NW. MODEL SOUNDINGS INDCG MID LVL CAP WILL STRENGTHEN DURING DAY SUN AS HI BUUILDS INTO REGION. WITH FRNTL BNDRY SAGGING INTO UPR TN VLY BY SUN AFTN/EVNG...THINKING MOST LOCATIONS WILL BE DRY THROUGHOUT DAY SUNDAY. THERE IS AN OUTSIDE CHANCE AT A -SHRA OR TWO ALONG AND SOUTH OF OHIO RIVER DURING AFTN HOURS...BUT CHANCE IS LOW ENUF TO KEEP MENTION OUT OF FCST ATTM. EXPECTING PTLY CLDY SKIES AS CU RULE AND MODEL SOUNDINGS SUGGESTING SCT/BKN CU DVLPG AS 850 CAA EXPANDS SOUTH WITH HI PRES. SKIES SHOULD BECOME MSTLY CLR SUN NIGHT AS CENTER OF SFC HI MOVES ACRS REGION. WITH LGT WINDS AND DECENT RADIATIONAL COOLING CONDITIONS SETTING UP...COULD BE ANOTHER FAVORABLE SETUP FOR FOG DVLPMNT LATE SUN NIGHT INTO MON MRNG. TEMPS...BOTH 12Z GFS AND NAM CAME IN COOLER WITH BNDRY LYR THICKNESSES THRU SHORT TERM...AND WITH 850 TEMPS. AS A RESULT... GENERALLY LOWERED TEMPS A FEW DEG FOR ALL THREE PERIODS. THIS LINED UP CLOSELY WITH MET GUID. RYAN LONG TERM /MONDAY THROUGH SATURDAY/... 500 MB FLOW FOR THE EXTENDED WILL BE WEST TO NORTHWEST...WHICH WILL KEEP DEEP TROPICAL/SUBTROPICAL MOISTURE TO OUR SOUTH. AT THE SURFACE HIGH PRESSURE WILL DOMINATE WITH ONLY TWO EXCEPTIONS. WILL KEEP MENTION OF PRECIP ACROSS FAR SOUTH MONDAY NIGHT AS BOTH NAM AND GFS BRING WAVE THROUGH KENTUCKY. BUT HAVE PULLED PRECIP OUT OF THE FAR SOUTH ON MONDAY AS THE EVOLUTION IS SLOWER WITH THIS RUN. MODELS HAVE BEEN SLIDING THIS WAVE A BIT FARTHER SOUTH...BUT DON'T FEEL GOOD ABOUT TAKING IT OUT OF MONDAY NIGHT. THE SECOND EXCEPTION IS A WEAK COLD FRONT WHICH WILL GO THROUGH TUESDAY NIGHT INTO WEDNESDAY. WILL KEEP THIS DRY BECAUSE OF TIMING OF FROPA AND STRENGTH...BUT WILL MONITOR THESE FACTORS FOR POSSIBLE INCLUSION IN THE NEXT PACKAGE. TEMPS WILL GENERALLY BE CLOSE TO NORMAL. TIPTON && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ oh AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE NORMAN OK 157 AM CDT SUN AUG 20 2006 EARLY MORNING CONVECTION IS GRADUALLY CENTERING AROUND HIGHER PORTIONS OF THE FRONTAL BOUNDARY WITH THE SURFACE BOUNDARY MOVING THROUGH WICHITA FALLS AND ARDMORE AT THIS TIME. THE 875-800 MB LAYER SEEMS THE MOST UNSTABLE WITH ITS LIFT SHIFTING NORTHWARD WITH TIME PER LATEST TRENDS AND RUC GUIDANCE. THEREFORE...LOWERED POPS TO BETWEEN 20-30 PERCENT NEAR AND SOUTH OF INTERSTATE 40 FOR THE REST OF TONIGHT AND RAISED THEM ACROSS NORTH CENTRAL OKLAHOMA. OVERNIGHT LOWS WERE ALSO RAISED SEVERAL DEGREES WITH ONLY WEAK COLD AIR ADVECTION BEHIND THE FRONT AND LONGWAVE RADIATION TRAPPED BY SEVERAL CLOUD DECKS. JAMES -------------------------- 933 PM CDT SAT AUG 19 2006 .UPDATE... MAIN FRONTAL BOUNDARY THIS EVENING EXTENDS FROM SOUTHWEST OKLAHOMA INTO CENTRAL AND NORTHEAST PARTS OF THE STATE. CONVECTION HAS BEEN INCREASING ACROSS CENTRAL SECTIONS DURING PAST HOUR WITH OVERALL DOWNWARD TREND IN TERMS OF STORM STRENGTH. HAVE SHIFTED HIGHEST POPS FARTHER SOUTH FOR REST OF NIGHT WITH A SLIGHT REDUCTION ACROSS NORTH CENTRAL SECTIONS. HOPEFULLY WAVE OVER CENTRAL TEXAS WILL LIFT NORTHWARD AROUND UPPER RIDGE AND PROVIDE ADDITIONAL LIFT/MOISTURE FOR CONVECTION OVERNIGHT. && SIX .PREV DISCUSSION... (ISSUED 331 PM CDT SAT AUG 19 2006) DISCUSSION... GIVEN TEMPS AOA 100 DEGREES...ALONG WITH HUMIDITIES HOVERING AROUND 20-25 PERCENT...WILL LET RED FLAG WARNING CONTINUE FOR ITS DURATION THIS EVENING DESPITE THE LIGHT WINDS. SCATTERED STORMS EXPECTED TO CONTINUE DEVELOPING THIS AFTERNOON AND EVENING EXPECTED ON/JUST NORTH OF WEAKENING/RETREATING FRONTAL BOUNDARY THAT WILL EXTEND FROM FAR SOUTHWEST OKLAHOMA...NORTHEAST THROUGH CENTRAL OKLAHOMA...INTO SOUTHEAST KANSAS. BASED ON AREA PROFILERS AND 88DS...SOUTHERN EDGE OF FRONT VERY SHALLOW AND MIXING SLOWLY NORTHWARD...BUT IS AROUND 1.5KM DEEP ACROSS NORTHERN OKLAHOMA AND SOUTHERN KANSAS. SECONDARY AND MORE SUBSTANTIAL FRONTAL BOUNDARY EXPECTED TO MAKE A RUN SOUTHWARD FROM KANSAS TONIGHT THROUGH SUNDAY BEHIND MID-LEVEL WAVE THAT IS PROGD TO PASS EASTWARD THROUGH KANSAS. COULD SEE TWO DEVELOPMENT PEAKS...ONE LATE THIS AFTERNOON AND EARLY EVENING NEAR THE RETREATING FRONTAL BOUNDARY ACROSS MAINLY WESTERN/NORTHWEST OKLAHOMA...AND ANOTHER TOWARD/AFTER MIDNIGHT AS COLD FRONT AND POSSIBLE STORM COMPLEX SURGES SOUTHWARD AND INTERACTS WITH MODEST S/SWLY LOW LEVEL JET. HIGHEST THREAT FOR SEVERE STORMS APPEARS TO BE THROUGH THE MID-EVENING HOURS AND PRIMARILY IN THE FORM OF DOWNBURST WINDS. MENTIONED FRONT EXPECTED TO MAKE IT TO AROUND THE RED RIVER VALLEY TOMORROW BEFORE STALLING. MODELS FAIRLY SIMILAR IN FRONTOLYSIS MONDAY AND TUESDAY...BUT WITH CAP WEAK DURING PEAK HEATING...WILL LEAVE CHANCE AND SLIGHT CHANCE POPS GOING THROUGH TUESDAY NIGHT. FORECAST WILL BE DRY AFTER THAT. EXTENDED RANGE MODELS BRING ANOTHER...AND POSSIBLY MORE SUBSTANTIAL COLD FRONT INTO REGION TOWARD THE END OF THE WEEK. PRIOR TO THIS FRONT... WE WILL WARM BACK UP TO JUST ABOVE AVERAGE...BUT CURRENTLY DO NOT ANTICIPATE WIDESPREAD TEMPS OVER 100 DEGREES. WILL BEGIN A COOLING TREND SATURDAY ACROSS THE NORTHERN HALF OF THE FORECAST AREA...BUT POPS WILL NOT BE INSERTED ATTM. && $$ ok AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SALT LAKE CITY UT 315 AM MDT SUN AUG 20 2006 .SYNOPSIS...SEVERAL WEAK WEATHER SYSTEMS WILL CROSS UTAH IN SOUTHWEST FLOW THROUGH MONDAY NIGHT. HIGH PRESSURE WILL STRENGTHEN ACROSS THE FOUR CORNERS REGION THROUGH TUESDAY. && .DISCUSSION...LITTLE CHANGE IN MOISTURE LAYER ACROSS UTAH THIS MORNING WITH .6 TO .7 INCH PRECIPITABLE WATER OVER EASTERN AREAS AND .4 TO .6 OVER THE WESTERN DESERTS AND VALLEYS. HOWEVER OLD WEST COAST SYSTEM IS LIFTING ACROSS UTAH THIS MORNING AS PROGGED BY MODELS AND CONTINUES TO DEVELOP SCATTERED NOCTURNAL THUNDERSTORMS OVER EASTERN UTAH WITH ISOLATED ACTIVITY OVER WESTERN AND SOUTHERN AREAS. RUC SOUNDINGS...SATELLITE LOOPS AND SURFACE OBSERVATIONS INDICATE MOST OF THIS IS ROOTED AS ELEVATED CONVECTION...OVER THE 20S AND 30S DEWPOINTS AND ABOVE VALLEYS AND MOUNTAINS. MAIN UPPER DISTURBANCE CENTER IS OVER NORTHEAST NEVADA AND SHEARING WITH TIME...WITH A 70 KNOT JET STREAK EXITING EASTERN UTAH. DYNAMICS EXIT EASTERN UTAH THIS MORNING WITH REMAIN UPPER TROUGH AXIS TRACKING ACROSS NORTHWEST UTAH. SOME CELLS WILL DEVELOP IN NORTHWEST UTAH AS A RESULT AND WITH CONDITIONAL UNSTABLE AIR MASS REMAINING OVER EASTERN UTAH THIS MORNING AN ISOLATED CELL COULD REDEVELOP. THE LATE MORNING AND AFTERNOON WILL TRANSITION INTO SURFACE BASED TERRAIN FORCED CONVECTION WITH NAM-WRF AND LOCAL WRF-NMM (AVAILABLE ON WEB PAGE) DEPICTING MORE SIGNIFICANT CAPE THIS AFTERNOON OVER THE SPINE OF UTAH INCLUDING THE OQUIRRHS AND TINTIC MOUNTAINS AND TO THE EAST. MORNING DISTURBANCE RIDES OVER THE RIDGE BUT ANOTHER VORT LOBE FORECAST TO LIFT ACROSS WESTERN UTAH THIS AFTERNOON AHEAD OF THE NEXT PACIFIC SYSTEM...WHICH WILL FURTHER DESTABILIZE THE AIR MASS THROUGH SYNOPTIC LIFT FOR INCREASED MOIST CONVECTION. AIR MASS WARMS ABOUT 1C TODAY ACROSS THE REGION AT 700 MB. NEXT WEST COAST SYSTEM IS STRONGER AND STILL FORECAST BY NAM-WRF AND GFS TO LIFT A VORT LOBE ACROSS WESTERN UTAH TONIGHT AND MONDAY MORNING WITH 500 MB WARM AIR ADVECTION IN ITS WAKE. THIS WILL BE FORCING FOR MORE NOCTURNAL THUNDERSTORMS TONIGHT INTO MONDAY MORNING WITH A MORE STABLE AIR MASS DEVELOPING MONDAY AFTERNOON OVER FAR WESTERN AREA AS DRIER AND WARM AIR ALOFT PUNCH INTO WESTERN UTAH. SCATTERED CONVECTION WILL STILL REDEVELOP AHEAD OF THIS...MOST OF IT FORCED BY TERRAIN MONDAY AFTERNOON WITH SUFFICIENT CAPE FROM THE SPINE OF UTAH AND EASTWARD. DRIER AND SLIGHTLY WARMER AIR PROGGED TO SPREAD ACROSS UTAH ON TUESDAY AS THE UPPER RIDGE STRENGTHENS OVER THE 4-CORNERS...AND ENERGY LIFTS NORTH INTO IDAHO AND MONTANA. EXPECT DECREASED CONVECTION OVER MUCH OF THE REGION. MID LEVEL FLOW FORECAST TO INCREASE OVER WESTERN UTAH WITH A HOT AIR MASS OF 16C AT 700MB. THIS DRY ADIABATICALLY MIXED WILL GIVE HIGHS CLOSE TO RECORDS IN THE NORTH. WEST COAST TROUGH BEGINS TO ELONGATE BY TUESDAY AND WEDNESDAY. 594-DM UPPER HIGH WEAKENS STARTING WEDNESDAY AND WESTERLY FLOW ALOFT SETS UP OVER UTAH. WESTERLIES JUST TO OUR NORTH WILL SEND DISTURBANCES THROUGH OUR REGION WEDNESDAY THROUGH FRIDAY WITH A COOL FRONT ACROSS THE NORTH ON THURSDAY. ALL MODELS LEAVE SOME ENERGY ALONG THE CALIFORNIA COAST. ENOUGH MOISTURE SOUTH OF THIS WILL ALLOW FOR WIDELY SCATTERED CONVECTION REST OF THE WEEK. UPPER RIDGE FORECAST TO BUILD AGAIN NEXT WEEKEND THOUGH ANOTHER UPPER LOW ON THE WEST COAST COMES INTO THE PICTURE. && .AVIATION...THERE IS A SLIGHT CHANCE OF HIGH BASED SHOWERS AND A LIGHTNING STRIKE THIS MORNING. BETTER CHANCE THIS AFTERNOON WITH THE ADDITIONAL OF GUSTY WINDS FROM OUTFLOWS. && .FIRE WEATHER...THUNDERSTORMS OVERNIGHT PRODUCED A LOT OF LIGHTNING FROM CASTLE COUNTRY THROUGH THE UINTAH BASIN MOVING ACROSS THE UINTA MOUNTAINS AT THIS HOUR. ADDITIONAL ISOLATED STORMS WILL AFFECT WESTERN AND NORTHERN UTAH THIS MORNING FOLLOWING THE THE UPPER TROUGH AXIS THAT IS LIFTING ACROSS NORTHERN UTAH BUT EXTENDS INTO SOUTHERN UTAH. THIS AFTERNOON WILL REDEVELOP SCATTERED CONVECTION WITH A GOOD THREAT FOR DRY LIGHTNING WESTERN ZONES ALONG WITH HIGH HAINES. WE HAVE UPGRADED AND EXPANDED RED FLAG WARNING FOR THIS... AND COORDINATED WITH SPC. MORE NOCTURNAL THUNDERSTORMS SHOULD DEVELOP LATER TONIGHT INTO MONDAY MORNING...ESPECIALLY WESTERN AREAS WHERE MARGINAL BUT SUFFICIENT MOISTURE IS IN PLACE. AIR MASS IS MORE STABLE WESTERN AND NORTHERN AREAS FOR TUESDAY AND WEDNESDAY BUT THIS WILL BE THE PEAK OF THE HOT PERIOD AND AFTERNOON AND EVENING BREEZES WILL REACH 25-30 MPH...BRINGING POSSIBLE RED FLAG CONDITIONS AGAIN. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...RED FLAG WARNING THIS AFTERNOON AND EVENING ZONES 420...423...424...433...434...435...436...437 WY...NONE. && $$ TARDY/SMITH ut WEST CENTRAL AND SOUTHWEST FLORIDA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL 948 AM EDT SUN AUG 20 2006 .MORNING UPDATE...LATEST W/V STLT AND RUC LOCATE AN UPPER LOW EAST OF FL...JUST NORTH OF THE BAHAMAS...MAKING SLOW PROGRESS TOWARD THE STATE. MSAS HAS A WEAK SURFACE RIDGE ACROSS CENTRAL FL THIS MORNING. THIS RIDGE WILL BUILD SLIGHTLY TO THE WEST DURING THE DAY. THE 12Z TBW RAOB CAME IN A BIT DRIER AND WARMER ALOFT THAN THE LAST COUPLE OF SOUNDINGS BUT FEEL THIS WILL BE NEGATED BY THE DECREASE IN CLOUD COVER FROM YESTERDAY AROUND THIS TIME. SO EXPECT ANOTHER ACTIVE DAY WITH COVERAGE IN THE LIKELY RANGE THIS AFTERNOON...ALTHOUGH THE GREATEST COVERAGE WILL BE FROM TAMPA BAY SOUTH ALONG WITH SOME STRONG STORMS IN THE FAR. THANKS IN PART TO A LITTLE MORE MOISTURE DOWN THERE. CURRENT ZONES LOOK ON TRACK AND WILL NOT UPDATE. && .MARINE...SURFACE DATA AND LIMITED QUICK SCAT IMAGES SUPPORT THE ONGOING FORECAST OF SE OR VARIABLE WINDS THAT SHIFT TO ONSHORE IN THE AFTERNOON. BIGGEST MARINE CONCERN WILL BE THUNDERSTORMS...SCATTERED OVER THE OPEN GULF BUT MORE NUMEROUS NEAR SHORE IN THE AFTERNOON. NEXT CWF OUT BY 1030 AM. && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ 09/RKR fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 1111 AM EDT SUN AUG 20 2006 .UPDATE... MORNING UPDATE RUNNING A LITTLE LATE...CONVECTION STILL PROGRESSING ACROSS MUCH OF THE LOWER AND MIDDLE OHIO VALLEY THIS MORNING. THIS ACTIVITY SHOULD CONTINUE THRU THE AFTERNOON...THOUGH USING CURRENT RADAR AND SAT TRENDS COMBINED WITH RUC DATA THINK THE BULK OF THE ACTIVITY WILL SHIFT ACROSS THE SOUTHERN PORTIONS OF THE AREA BASICALLY SOUTH OF A LINE FROM HARTFORD TO JAMESTOWN...HAVE SIGNIFICANTLY RAISED POPS IN THIS AREA. WILL HAVE TO WATCH FOR BOTH SOME GUSTY WINDS IN THE STORMS...AS WELL AS PRECIP TOTALS THAT MAY SPELL FOR SOME MINOR FLOODING ISSUES AS THAT AREA HAS BEEN VERY DRY THIS SUMMER. STORMS ARE LINED UP TO THE WEST BACK TOWARDS WESTERN MO...AND SHOULD CONTINUE TO PROPAGATE ALONG THE 850 MB FRONT INTO OUR AREA AS THE AFTERNOON PROGRESSES BEFORE ALL SHIFTS FURTHER SOUTH TONIGHT. MADE SOME TWEAKS TO TEMPS AND CLOUDS...THINKING THAT A BIT MORE SUNSHINE MAY OCCUR ACROSS THE NORTHERN PORTIONS OF THE AREA AS SOME DRIER AIR WORKS SOUTH...DEW POINTS AT IND 57...BMG 59...CVG 64...AS COMPARED TO MOSTLY LOWER 70S STILL ACROSS MUCH OF THE AREA OUTSIDE THE BLUEGRASS AND ALLOW FOR A DEGREE OR TWO WARMER THERE THAN PREVIOUS THINKING. --SCHOTT && PREV DISCUSSION... (ISSUED 705 AM EDT SUN AUG 20 2006) UPDATE... SMALL MCS MOVING THROUGH THE LOU-LEX CORRIDOR. MANY REPORTS OF HIGH WINDS AND POWER OUTAGES...ALONG WITH HEAVY RAINFALL AND MINOR FLOODING. ISSUING A QUICK UPDATE TO INCREASE POPS TO LIKELY THROUGH THE MID-MORNING HOURS WITH ONGOING CONVECTION. ADDITIONAL STORMS DEVELOPING NEAR STL WITHIN PAST HOUR MAY EVENTUALLY AFFECT CWA LATER...WILL HAVE TO WATCH. UPDATED FORECAST OUT SHORTLY. PREV DISCUSSION... (ISSUED 240 AM EDT SUN AUG 20 2006) SHORT TERM (TODAY-TONIGHT)... PW VALUES REMAIN UNSEASONABLY HIGH ACROSS THE REGION BASED ON 0Z SOUNDINGS...AROUND 160% OF NORMAL AT ILX/OHX. THIS ALONG WITH WEAK SHORTWAVE(S) TRANSLATING E/SE THROUGH IL/MO...AND SFC FRONT ALONG THE OHIO RIVER...ARE HELPING GENERATE SCT CLUSTERS OF NOCTURNAL TSRA. AS OF 0630Z...STRONGEST/MOST ORGANIZED STORMS ARE DROPPING E/SEWD THROUGH SRN IL AND LOOK TO IMPACT PARTS OF CNTRL/SRN KY AROUND OR AFTER 8Z. WILL GO WITH LIKELY POPS ROUGHLY ALONG/SW OF A HNB-FTK-SME LINE THROUGH 12Z. EXPECTING ISLTD-SCT SHRA WITH EMBEDDED THUNDER EXPECTED ELSEWHERE IN THE CWA THROUGH 12Z. WILL MAINTAIN SCT PRECIP COVERAGE DURING THE BALANCE OF THE MORNING OVER MOST OF THE CWA. PATCHY FOG WILL CONTINUE THROUGH DAYBREAK...BUT SO FAR VSBYS HAVE NOT BEEN TOO LOW (GENERALLY BETWEEN 2-4SM WITH LOCAL REDUCTIONS TO 1SM). HAVE AGAIN FOLLOWED LATEST SREF RUN (21Z/19) FOR MUCH OF THE SHORT TERM FORECAST PERIOD. WE EXPECT SFC FRONT TO MAKE SLOW PROGRESS SOUTH TODAY INTO SRN KY AND TENN...WITH SLIGHTLY DRIER AIR ALOFT FILTERING INTO SRN IND THIS AFTN. BEST COVERAGE OF PRECIP TODAY SHOULD BE OVER SRN KY CLOSER TO SFC FRONT AND AXIS OF INSTABILITY. WILL GO WITH LIKELY POPS DOWNSTATE THIS AFTN...WITH CHANCE POPS ELSEWHERE. LOCALLY HEAVY RAINFALL SEEMS TO BE THE PRIMARY THREAT WITH HIGH PWS/FRZ LEVELS. BEST SVR POTENTIAL TODAY WOULD APPEAR TO BE INTO TENN WHERE WET MICROBURST PARAMETER EXCEEDS SVR THRESHOLDS. STILL...NOT OUT OF THE QUESTION TO GET A FEW STRONG/MARGINALLY SVR STORMS IN FAR SRN KY IF SUFFICIENT INSTABILITY CAN DEVELOP. ACTIVITY SHOULD WANE QUICKLY AFTER SUNSET PER SREF DATA...THOUGH HAVE KEPT SOME LOW CHC POPS IN SRN KY UNTIL MIDNIGHT GIVEN FCST K-INDICES ABOVE 25 IN THAT AREA. SKIES SHOULD AT LEAST PARTIALLY CLEAR TONIGHT...ALLOWING FOR PATCHY FOG TO FORM ONCE AGAIN. LIMITING FACTOR FOR WIDESPREAD FOG FORMATION WILL BE 10-15KT LOW LEVEL WINDS FCST BY THE NAM. CS LONG TERM (MONDAY-SATURDAY)... MONDAY THROUGH TUESDAY NIGHT... SHORT AND MEDIUM RANGE MODELS CONTINUE BE IN GOOD AGREEMENT THROUGH THIS PART OF THE FORECAST PERIOD. OVER THE LAST FEW RUNS...THE MODELS HAVE BEEN KEEN ON TRACKING A LITTLE VORT COMING AROUND THE TOP OF THE DEPARTING H5 RIDGE TO OUR SOUTHWEST. TONIGHTS MODELS CONTINUE TO SUPPORT THIS BY TAKING THE VORT AND SWINGING IT MAINLY THROUGH KY WITH ASSOCIATED SFC LOW TRACKING THROUGH TN. THIS WILL BRING ANOTHER CHANCE OF SHOWERS TO THE AREA MONDAY AND MONDAY NIGHT. CURRENT FCST HAS THIS COVERED...SO ONLY SOME MINIMAL CHANGES ARE NEED AT THIS TIME. WILL CONTINUE TO RUN CHANCE POPS FOR MONDAY AND MONDAY NIGHT AND BEGIN TO DRY THINGS OUT ON TUESDAY. GIVEN THE CLOUDS AND ASSOCIATED PRECIPITATION EXPECTED...TEMPS WILL SOMEWHAT COOLER THAN IN PREVIOUS DAYS WITH HIGHS IN THE MID 80S. CLEARING WILL BEGIN TO WORK ITS WAY INTO THE REGION ON TUESDAY WITH TEMPERATURES STILL IN THE MID 80S IN THE NORTH AND PERHAPS CLIMBING INTO THE UPPER 80S ACROSS FAR SOUTH KY. WEDNESDAY THROUGH SATURDAY... UPPER LEVEL THROUGH THIS PERIOD LOOKS TO FLATTEN OUT A BIT AS TROFFING IN THE EASTERN U.S. BEGINS TO BECOME MORE ZONAL AS SERIES OF POTENT H5 WAVES FLATTEN OUT THE WESTERN UNITED STATES RIDGE. FAIRLY TRANQUIL WEATHER IS EXPECTED THROUGH THE PERIOD. TEMPERATURES WILL BEGIN THE PD NEAR NORMAL AND AS ZONAL FLOW TAKES OVER...WE SHOULD START TO SEE SLOWLY MODERATING TEMPERATURES FROM MIDWEEK ONWARD. BY LATE IN THE PERIOD...DECENT H5 WAVE WILL BE PASSING THROUGH THE GREAT LAKES WITH ASSOCIATED COLD FRONT BOUNDARY TRYING TO MAKE IT SOUTHEASTWARD TOWARDS THE OHIO VALLEY. LATEST MODEL GUIDANCE SUGGEST THAT FRONT MAY MAKE IT TO THE OHIO RIVER BEFORE STALLING OUT AS SOUTHEAST RIDGE KEEPS IT FROM MAKING ANY REAL HEADWAY. MODEL PROGS ALSO SHOW THAT BEST PRECIPITATION CHANCES WILL LIKELY BE AFTER THIS FCST PD...AROUND SUNDAY OR SO. THUS...WILL CONTINUE A DRY FORECAST FOR NOW. AS FOR TEMPS...WILL ADJUST THOSE CLOSER TO THE ENSEMBLE MEANS WHICH HAVE PERFORMED WELL AND SHOWN GOOD RUN TO RUN CONTINUITY OVER THE PAST FEW DAYS. -MJ && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON KY 1101 AM EDT SUN AUG 20 2006 .DISCUSSION... PRIMARY FORECAST PROBLEM FOR UPDATE IS TEMPERATURES FOR THE REST OF TODAY. WITH THE PASSAGE OF THIS MORNINGS MCS...HOURLY TEMPERATURES AT SEVERAL SITES ACROSS FORECAST AREA ARE NOW SEVERAL DEGREES LOWER THAN PREVIOUSLY FORECAST. WITH THIS IN MIND...DECIDED TO DECREASE AFTERNOON HIGH TEMPERATURES ACROSS THE BOARD TO A CATEGORY BELOW PREVIOUS FORECAST. ALSO REMOVED MENTION OF FOG FROM FORECAST...AS WINDS FROM MCS PASSAGE HAVE HELPED TO BREAK UP QUITE A BIT OF THE FOG THAT WAS PRESENT IN VALLEY LOCATIONS THIS MORNING. REST OF FORECAST WAS IN GOOD SHAPE. && .PREV DISCUSSION... 430 AM EDT SUN AUG 20 2006 COLD FRONT HAS DROPPED INTO THE NORTHERN PORTIONS OF OUR CWA THIS MORNING. A THIN LINE OF SCATTERED SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ALONG THE BOUNDARY...WITH A FEW ADDITIONAL POCKETS OF SHOWER AND THUNDERSTORMS OUT AHEAD OF THE FRONT. OTHERWISE...AN MCS WAS TRACKING EASTWARD THROUGH WESTERN KENTUCKY. EXPECT THIS FEATURE TO WEAKEN SOME AS IT PROGRESSES EASTWARD INTO A MORE STABLE ENVIRONMENT AND WHERE THE ATMOSPHERE HAS BEEN WORKED OVER DURING THE OVERNIGHT. RUC ANALYSIS AND RADAR CONFIRMS THIS TREND. EXPECT SHOWERS AND THUNDERSTORMS TO CONTINUE TO DEVELOP ALONG AND AHEAD OF THE FRONT AS IT SLIDES SOUTHWARD THROUGH THE DAY. ACTIVITY WILL INTENSIFY IN COVERAGE AND STRENGTH LATER IN THE AFTERNOON WITH HELP OF DAY TIME HEATING AND AS SOME SHORT WAVE ENERGY MANAGES TO MAKE ITS WAY INTO THE AREA. PERSISTENCE WOULD SUGGEST THAT ONE OR TWO STORMS MAY EVEN MAKE IT TO SEVERE LEVELS THIS AFTERNOON WITH THE MAIN THREAT BEING HIGH WINDS. ALSO...SOME LOCALLY HEAVY RAINFALL WILL BE POSSIBLE. WILL MENTION THESE IN THE HWO. WILL SEE A BRIEF REPRIEVE FROM SHOWER ACTIVITY LATER TONIGHT. AFTERWARDS...MODELS STILL DEVELOP A WAVE OF LOW PRESSURE AND TRACK IT EASTWARD BETWEEN THE TN AND OH VALLEYS LATE MONDAY INTO TUESDAY. NAM IS FURTHER SOUTH AND FASTER WITH ANY ENERGY ASSOCIATED WITH THIS DISTURBANCE AS COMPARED TO THE GFS. FOR NOW STAYED WITH THE MORE CONSISTENT GFS SOLUTION. BEST LIFT OVER EASTERN KENTUCKY APPEARS TO OCCUR DURING THE MONDAY NIGHT...TUESDAY TIME FRAME. SO HIT POPS HARDEST DURING THIS PERIOD. 930 PM EDT SAT AUG 19 2006 S/WV HAS MOVED THRU THE AREA AND MOST OF THE CONVECTION NOW EAST/SOUTH OF CWFA. ISOLATED CONVECTION POPPING UP IN CNTRL KY BUT DIMINISHES TO BARELY -RA BY THE TIME IT GETS TO I-75. WX OF GREATEST CONCERN IS THE SHRA ALONG THE QUASI-STATIONARY FNT FM PMH TO CVG AND CONVECTIVE COMPLEX ON THE WRN FRINGE OF CNTRL KY CWFA. HAVE KEPT CHC POP IN NORTH FOR FNTL CONVECTION AND FEEL THE MCS IN WRN KY WILL HOLD AT BAY UNTIL AFTER SUNRISE. LOCALLY DENSE FOG IN VLYS IS SPILLING ONTO RIDGES IN LIGHT SRLY BREEZE. LIGHT WIND SHOULD GO CALM TONITE AND FOG WILL SETTLE BUT THE DEPTH OF THE MOIST/SATURATED AIR MAY PRECLUDE ANY SIGNIFICANT DROP IN TEMP. ALREADY INTO THE LOWER 70S AND HAVE PROJECTED LOWS IN THE NRN 2/3 CWFA TO ONLY DROP A COUPLE OF DEG FROM CURRENT TEMPS...PUTTING THEM BARELY INTO THE UPPER 60S. 536 PM EDT SAT AUG 19 2006 SW/V IS MOVING FROM THE OH VALLEY AND INTO THE CENTRAL APPALACHIANS LATE THIS AFTERNOON. UPPER TROUGH WAS MOVING FROM THE UPPER MIDWEST AND INTO THE GREAT LAKES. MCS DEVELOPED OVER THE CWA AHEAD OF THE SW/V AND MAINLY PRODUCED LOCALLY HEAVY RAIN OF AN INCH TO AN INCH AND ONE HALF IN ABOUT ONE HALF OF AN HOUR. STRATIFORM RAIN LINGERS OVER THE EASTERN 2/3 OF THE CWA...WITH ONLY A COUPLE OF POCKETS OF INSTABILITY LEFT NEAR THE VA AND TN BORDERS. AT THE SFC...AN AREA OF LOW PRESSURE WAS OVER EASTERN LAKE ERIE...WITH A COLD FRONT TRAILING SW TO NEAR KCMH TO KILN TO KHNB TO NEAR KMVN AND THEN WAS STATIONARY DOWN INTO WESTERN TX. THE INITIAL SW/V SHOULD PASS EAST OF THE EVENING...WITH SW/V RIDGING WORKING ACROSS THE REGION DURING THE EVENING...LEADING TO A LULL IN THE CONVECTION. WE EXPECT FOG DEVELOPMENT WHERE ANY HOLES IN THE CLOUDS ARE PRESENT. THE SFC COLD FRONT WILL GRADUALLY SAG INTO THE NORTHERN PART OF THE CWA BY 12 SUN. HOWEVER...EXPECT VERY LITTLE CONVECTION OVERNIGHT IN THE CWA...WITH SOME POSSIBLY FORMING TO OUR WEST VERY LATE AS THE TROUGH AXIS APPROACHES. THE TROUGH AXIS CROSS THE AREA DURING THE DAY AND MODEL CONSENSUS IS THAT CONVECTION WILL FROM IN THE MID TO LATE MORNING AND MOVE TO THE SOUTH OF THE CWA DURING THE EVENING AS THE FRONT CONTINUES TO MOVE SOUTH AND BE MORE WIDESPREAD OVER THE SW 2/3 OF THE CWA IN WARMER AND SLIGHTLY MORE MOIST AIRMASS OUT AHEAD OF THE FRONT AND WENT LIKELY THERE FOR SUN. LOW TEMPS TONIGHT WERE TRICKY...WITH TEMPS ALREADY NEAR MOS GUIDANCE LOWS IN THE RAIN COOLED AIR. MOS NUMBERS WERE CLOSE AND WENT WITH A BLEND OVERALL AND CLOSE TO THE PREVIOUS FORECAST. FOG COULD DRIVE TEMPS DOWN FURTHER...AND LATER SHIFTS WILL MONITOR. TEMPS ON SUN WILL ALSO BE TRICKY...AND HIGHLY DEPENDENT ON PRECIP AND FROPA TIMING. OVERALL TRENDED TEMPS DOWN ON SUN. MODELS CONTINUE TO INDICATE THAT THE FRONT WILL GET HUNG UP OVER THE TN VALLEY. AS ANOTHER SW/V DROPS SOUTH AND SHARPENS THE BROAD EASTERN TROUGH THAT WILL BE IN PLACE EARLY IN THE WEEK. A COUPLE OF SFC WAVES ARE EXPECTED TO TRACK NE ALONG THE BOUNDARY. CONTINUED UPWARD TREND OF POPS WITH MORE RUN TO RUN CONSISTENCY WITH THIS IDEA...MAINLY ON MON NIGHT AND DURING THE DAY ON TUE...WHEN BEST UVV IS INDICATED OVER THE AREA. EXTENDED (OZ WED THROUGH 12Z SUN)...ONLY A FEW SLIGHT CHANGES MADE TO EXTENDED PORTION OF FORECAST. LATEST GFS HAS AN MORE DIFFUSE FRONT MOVING SOUTH ACROSS THE OHIO VALLEY WEDNESDAY NIGHT INTO THURSDAY. IN FACT...IT IS VERY DIFFICULT TO EVEN FIND THE FRONT IN THE MODEL DATA. MODEL CROSS SECTIONS WITH A VERY SHALLOW LAYER OF MOIST AIR NEAR THE SURFACE PRETTY MUCH THE WHOLE WEEK. THIS WARRANTED LEAVING IN PARTLY TO MOSTLY CLOUDY SKIES...BUT DEFINITELY NOT PRECIPITATION. REMOVED PRECIPITATION CHANCES FROM THE FORECAST THROUGH NEXT FRIDAY. GFS AND ECMWF BOTH TRYING TO MOVE A FRONTAL WAVE UP THE EAST COAST...JUST TO THE EAST OF THE APPALACHIAN MOUNTAINS NEXT SATURDAY...SO DECIDED TO ADD POPS TO THAT PORTION OF THE FORECAST. MADE CORRESPONDING ADJUSTMENTS TO QPF...SKY...AND WEATHER GRIDS FOR NEXT SATURDAY AS WELL. TEMPERATURES LOOKED PRETTY GOOD AS WELL. DECIDED TO INCREASE DAYTIME HIGHS BY A DEGREE OR SO ACROSS THE BOARD...AS MEXMOS NUMBERS HAVE COME IN A BIT HIGHER EACH OF THE PREVIOUS 3 RUNS. A FEW TWEAKS WERE ALSO MADE TO DEWPOINTS...AS LATE IN THE WEEK THEY SEEMED A BIT HIGH. WINDS WERE IN GOOD SHAPE AND WERE LEFT ALONE. && .JKL WATCHES/WARNINGS/ADVISORIES...NONE. && $$ RAY/AR ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1037 AM EDT SUN AUG 20 2006 .UPDATE... VIS SATELLITE SHOWS THE EARLY MORNING LOW CLOUDS ARE RAPIDLY STRIPPING AWAY...WITH THE SAGINAW VALLEY ALREADY SUNNY. CLOUDS ARE HOLDING LONGER ACROSS THE THUMB WITH SOME HELP WITH THE UNSTABLE NORTHERLY FLOW OFF LAKE HURON...HOWEVER EVEN THE BACK EDGE OF THE CLOUDS OUT ACROSS THE OPEN LAKE IS STEADILY DROPPING SOUTHWARD. 12Z DTX/APX SOUNDINGS SHOW THE STORY...WITH DTX SATURATED BELOW 850MB WHILE APX BEGINS TO DRY OUT JUST ABOVE THE SURFACE. 12Z RUC/NAM TEMPERATURE/DEWPOINT PROFILES STILL SUPPORT SOME CU DEVELOPMENT TODAY...WITH DEWPOINTS IN THE UPPER 50S AND 850MB TEMPERATURES AROUND 9C. HOWEVER GIVEN THE STRONG SUBSIDENCE AND DRYING BEHIND THE SHORTWAVE DOWNSTREAM OVER SOUTHWEST ONTARIO...DO NOT EXPECT THESE CLOUDS TO PERSIST VERY LONG. WILL UPDATE TO ADJUST SKY COVER GIVEN THE CLEARING THAT HAS ALREADY DEVELOPED. WILL CARRY DRIZZLE OF LIGHT SPRINKLES FOR A COUPLE MORE HOURS ACROSS THE EASTERN CWA AS RADAR/SATELLITE STILL INDICATE SOME WEAK ACTIVITY DOWNSTREAM OF LAKE HURON. && .PREV DISCUSSION...ISSUED 742 AM EDT SUN AUG 20 2006 AVIATION... LOW LEVEL FLOW OFF OF LAKE HURON EXPECTED TO CONTINUE ENHANCING ALREADY GOOD LOW LEVEL MOISTURE TO HELP KEEP MVFR LOW CLOUDS AROUND MOST OF THE MORNING IN WEAKLY CYCLONIC LOW LEVEL FLOW...THOUGH CEILINGS SHOULD SLOWLY LIFT. SCATTERED CLOUDS EXPECTED BY EARLY AFTERNOON...OCCASIONALLY VFR BROKEN UNTIL LATE AFTERNOON THANKS TO DIURNAL DEVELOPMENT. MOSTLY CLEAR TONIGHT...BUT HAVE MENTIONED VISIBILITIES 5 MILES IN MIST/LIGHT FOG BY 09Z WITH GOOD RADIATIONAL COOLING AS HIGH PRESSURE DRIFTS DIRECTLY OVER THE AREA. && PREV DISCUSSION...ISSUED 456 AM EDT SUN AUG 20 2006 MARINE... DECIDED TO ADD INNER SAGINAW BAY TO SMALL CRAFT ADVISORY TODAY...AS LATEST RUNNING OF THE WAVE MODEL BRINGS CRITERIA FOR WAVES INTO THE INNER PART OF THE BAY AS WINDS TURN TO EAST OF NORTH. WATCHES/WARNINGS/ADVISORIES SECTION BELOW ALSO UPDATED. PREV DISCUSSION...ISSUED 354 AM EDT SUN AUG 20 2006 SHORT TERM...TODAY AND TONIGHT BROAD SURFACE/LOW LEVEL CYCLONIC FLOW LINGERING OVER SOUTHEAST MI THIS MORNING...GIVING WAY TO HIGH PRESSURE BUILDING IN FROM THE WEST AND SETTLING OVERHEAD TONIGHT. MEANWHILE AT 500 MB...EASTERN GREAT LAKES SHORTWAVE TROUGH CONTINUING EAST TODAY WITH SHORTWAVE RIDGING SETTING UP OVER FORECAST AREA TODAY AND CONTINUING TONIGHT. MOISTURE IN MID TO UPPER LEVELS VERY SPARSE AS PER MODEL CONSENSUS AND WATER VAPOR IMAGERY...EXPECTED TO REMAIN SO THROUGH TONIGHT. LOW LEVEL MOISTURE IS MORE PROBLEMATIC. QUITE OF BIT OF LOW MOISTURE...SUCH AS AT 925 MB...AROUND THIS MORNING...BUT GFS MUCH FASTER DIMINISHING THIS MOISTURE THAN IS NAM/LOCAL WRFHEMI/NGM. MODEL SOUNDINGS ALSO SHOW THIS. GIVEN VEERING FLOW WITH MOIST AIR TRAJECTORIES OFF OF LAKE HURON...AM LEANING MORE TOWARD THE DELAYED DEPARTURE OF LOW CLOUDS...AND THUS CLOUDS ONLY GRADUALLY DIMINISHING THROUGH THE DAY. ALSO...AWIPS NAM CUMULUS RULE PROMISES BROKEN DIURNAL CLOUD DEVELOPMENT. FAR SOUTHERN COUNTIES SHOULD SEE THE LEAST CLOUD COVER...AS PER CLOUD ADVECTION/DEVELOPMENT TREND ACROSS THE AREA SINCE MIDNIGHT. GENERAL LOW TO MID LEVEL SUBSIDENCE THROUGH TONIGHT AS PER QVECTOR FIELDS AND DESCENT SEEN ON 300K/305K ISENTROPIC SURFACES. TEMPERATURES TODAY TENDING TO BE A FEW DEGREES COOLER THAN YESTERDAY...IN AGREEMENT WITH T1 GUIDANCE TRENDS. ALSO NOTICEABLY LESS HUMID TODAY THAN YESTERDAY...AS SURFACE DEW POINTS ARE EXPECTED TO BE ABOUT 10 DEGREES LOWER TODAY. WITH LIGHT WINDS AND SURFACE HIGH PRESSURE RIGHT OVERHEAD TONIGHT...WILL RETAIN PATCHY FOG MENTION. SOME PATCHES OF FOG/MIST CURRENTLY SEEN WITH UPSTREAM HIGH. LONG TERM...MONDAY THROUGH SATURDAY JUST WHEN NUMERICAL SUITE WAS BEGINNING TO SHOW SOME SIGNS OF STABILITY...THIS MORNINGS COMPUTATIONS SHOW OTHERWISE. CULPRITS ARE INITIALIZATIONS OF WAVES FROM ALASKA DOWN TO 40N BETWEEN 150-140W AND THE IMPACT OF THESE WAVES WITH CONVECTIVE FEEDBACK SIGNALS FOR THE MID WEEK PERIOD. THE GFS SEEMS TOO AGGRESSIVE BREAKING DOWN THE RIDGE ACROSS THE GREAT LAKES WITH STRONG CONVECTIVE DEVELOPMENT OVER THE PLAINS THEN TRACKING ITS ELEMENTS EAST WHILE THE ECMWF/UKMET/CANADIAN/WRF-HEMI LOOK MORE REASONABLE BUT THESE TOO HAVE COMPLICATIONS WITH OVERALL CONVECTIVE TRENDS FOR THE UPCOMING WEEK. AS EXPECTED...WESTERLIES WILL BE ACTIVE THIS WEEK WITH LEAD SHORT WAVE APPROACHING LAKE WINNIPEG THIS MORNING WILL REMAIN WELL NORTH OF THE LOCAL AREA MONDAY THROUGH TUESDAY. ASSOCIATED COLD FRONT WILL APPROACH THE LOWER LAKES LATE MONDAY NIGHT INTO TUESDAY WITH LITTLE IN THE WAY OF MOISTURE OR UPPER SUPPORT. NEVERTHELESS...TIMING OF THIS FRONT DOES MOVE IT THROUGH DURING THE PEAK HEATING ON TUESDAY AND THIS PUSHES CAPES TO BETWEEN 1000-1500 J/KG WITH MID LEVEL LAPSE RATES OF 6.5 C/KM. CURRENT FORECAST FOR CHANCE OF SHOWERS AND SLIGHT CHANCE FOR THUNDER LOOKS GOOD AT THIS TIME WITH NO CHANGES. WITH FROPA...ALBEIT SLOWER MIGRATION SOUTHWARD...TUESDAY NIGHT COULD SEE LINGERING CONVECTION BEFORE DISSIPATING WITH LOSS OF THE SUNSHINE AND WEAKENING SURFACE CONVERGENCE. THE QUESTION WILL BE JUST HOW MUCH COLD ADVECTION OCCURS OVER LAKE HURON OVERNIGHT. THE NMM SUGGESTS LAKE EFFECT RAIN SHOWERS WITH 1000-850MB LAPSE RATES OVER 7.5 C/KM WITH THE OTHER VARIOUS MODELS NOT ONLY WARMER BUT LESS PRONOUNCED WITH THERMAL TROUGH OVER LAKE HURON. AS THE NMM RESOLUTION IS HIGHER AND IT MORE MESOSCALE THAN ITS COUNTERPARTS...PREFER TO INTRODUCE A SLIGHT CHANCE FOR RAIN SHOWERS OVERNIGHT FOR SOUTH LAKE HURON AND INCLUDE HURON COUNTY. SURFACE HIGH SLIDES INTO THE GREAT LAKES FOR WEDNESDAY THEN UPSTREAM CONVECTIVE TRENDS WILL DICTATE THE REMAINDER OF THE FORECAST. AS NOTED IN THE SWODY3 AND CURRENT ECMWF...HEIGHT FALLS WILL COMMENCE WITH THE APPROACH OF VORTEX IN THE GULF OF ALASKA TRACKING JUST NORTH OF THE U.S. BORDER. LEE SURFACE CYCLOGENESIS WILL NOT ONLY INCREASE THE LOW LEVEL JET BUT MOISTURE TRANSPORT AND INCREASED SHEAR FOR SEVERAL COMPLEXES TO DEVELOP. WHILE THE GFS IS LIKELY TOO OVERDEVELOPED...MID LEVEL WARM FRONT SHOULD LIFT NORTHWARD ACROSS THE LAKES THURSDAY NIGHT AND THE CHANCE FOR ELEVATED THUNDERSTORMS. THEN WITH WARM AND INCREASED MOIST/UNSTABLE AIRMASS IN ADVANCE OF A COUPLE OF FRONTAL SYSTEMS WILL PROVIDE THE CONTINUED CHANCE FOR CONVECTION THROUGH THE FRIDAY-SATURDAY TIME PERIOD. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY...LHZ422...UNTIL 6 PM SUNDAY. SMALL CRAFT ADVISORY...LHZ421-LHZ441...UNTIL 6 PM SUNDAY. SMALL CRAFT ADVISORY...LHZ442-LHZ443...UNTIL 9 PM SUNDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ UPDATE.......BRAVENDER AVIATION.....DWD MARINE.......DWD SHORT TERM...DWD LONG TERM....BGM YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BINGHAMTON NY 940 AM EDT SUN AUG 20 2006 .SHORT TERM (TODAY - MONDAY)... UPDATE - GFS/NAM PROFILES STILL SHOWING SIG DIFFS W/RESPECT TO CONVECTIVE POTNL THIS AFTN, WITH GFS PROFILES MUCH MORE STABLE AND INDICATING LITTLE IF ANY ACTIVITY TDA, WHILE NAM INDICATES POTNL FOR MODEST CONVECTION. THE RUC PROFILES APPEAR TO BE A GOOD COMPROMISE, WITH CAPES POTNLY IN THE 300-400 RANGE THIS AFTN AND LI'S OF ARND -1 TO -2. HOWEVER, ALL PROFILES SUGGEST A STRENGTHENING AND LOWERING SUBSIDENCE INVERSION IN THE 600-700 MB LAYER THIS AFTN. THIS FEATURE IS EVIDENT IN THE 12Z BUF SNDG, AND IS MUCH STRONGER IN THE UPSTREAM DTX/APX 12Z SNDGS. WILL KEEP CHC POPS, BUT PRBLY SCALE BACK TO 30 POPS FOR THE CNTRL SRN TIER AND NE PA. BETTER CHCS ACRS THE FINGER LAKES, WRN MOHAWK VLY, SRN TUG AND NRN SUSQ RGN WHERE BETTER FORCING FROM THE APRCHNG S/WV WILL BE EVIDENT, AIDED BY SOME LOW LVL CONVERGENCE AS 2NDRY SFC TROF DROPS SWD. LOOKING BACK AT LAST NGT, HEAVIER PCPN AXIS FORMED JUST N OF THE NY/PA BORDER, WITH SVRL RPTS OF 2-3 INCHES AND EVEN A FEW 3.5 INCH AMTS. NO PRBLMS RPTD DUE TO ANTECEDENT DRY CONDITIONS. PREV AFD BLO... BACK EDGE OF THE HEAVIER RAIN IS PUSHING ACROSS OUR EASTERN ZONES AS OF THIS WRITING...AND IT SHOULD BE THROUGH THESE AREAS BY AROUND 4 AM. THIS WILL LEAVE SOME SCATTERED LIGHTER SHOWERS FOR THE REGION THIS MORNING...AS A WEAK SURFACE TROUGH MOVES ACROSS NY AND PA. THIS AFTERNOON...ENOUGH MIXING SHOULD DEVELOP TO ALLOW THE SUN TO BREAK THROUGH THE CLOUDS AT TIMES...ESPECIALLY ACROSS NORTHEAST PA. AT THE SAME TIME...THOUGH...ANOTHER UPPER-LEVEL WAVE IS EXPECTED TO CROSS UPSTATE NY LATE TODAY INTO THIS EVENING. SOME COOLING ALOFT/HEIGHT FALLS WITH THIS FEATURE COULD DESTABILIZE THE ATMOSPHERE SUFFICIENTLY TO BRING A FEW SHOWERS OR THUNDERSTORMS BACK INTO THE FORECAST AREA BETWEEN ROUGHLY 3 AND 9 PM...PARTICULARLY FOR THE NORTHERN ZONES. LATER TONIGHT AND MONDAY...MORE PRONOUNCED SINKING MOTION/DRYING DEVELOPS IN THE WAKE OF THE ABOVE MENTIONED UPPER WAVE. CONSEQUENTLY...WE SHOULD SEE AT LEAST PARTIAL CLEARING AFTER MIDNIGHT...WITH A MAINLY SUNNY DAY EXPECTED MONDAY. -MJ && .LONG TERM (MONDAY NIGHT - SATURDAY)... THE EXTENDED STARTS OUT WITH UPPER TROF LIFTING OUT AND UPPER RIDGE BUILDING FOR MOST OF THE REMAINDER OF THE PERIOD. DAY 3-4 RESIDUAL CYCLONIC CIRCULATION ON THE SURFACE/PASSING TROF BRINGS A SLIGHT CHC OF SHOWERS. LARGE DRY HIGH PRESSURE BUILDING IN AND SLOWLY MOVING OFFSHORE FOR THE REMAINDER OF THE PERIOD. - JFC && .AVIATION (20/12Z TO 21/12Z)... MVFR TO OCCASIONAL IFR RESTRICTIONS EXPECTED THIS MORNING WITH LOWER CEILINGS...LIGHT FOG...AND SCATTERED SHOWERS. FOR THE LATE MORNING AND AFTERNOON HOURS...GENERAL IMPROVEMENT ANTICIPATED AS CONDITIONS RETURN TO VFR. WEST TO NORTHWEST SURFACE WINDS SHOULD INCREASE TO 10-15 KT THIS AFTERNOON. SOME HIT AND MISS SHOWERS OR THUNDERSTORMS ARE EXPECTED ONCE AGAIN LATE THIS AFTERNOON INTO THE EVENING (BETWEEN ABOUT 21Z AND 03Z). HOWEVER...THE FAIRLY ISOLATED NATURE OF THEM PRECLUDES THEIR MENTION IN THE TERMINALS AT THIS JUNCTURE. -MJ && .BGM WATCHES/WARNINGS/ADVISORIES... .NY...NONE. .PA...NONE. $$ ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 1007 AM CDT SUN AUG 20 2006 .UPDATE... MORNING UPDATE WILL MAINLY ADDRESS POTENTIAL FOR AFTERNOON/ EVENING CONVECTION. THERE ARE CURRENTLY SOME ECHOES ON RADAR SOUTH OF KBIS AND EAST OF KMOT. THESE STORMS ARE ELEVATED IN NATURE... ASSOCIATED WITH THE LOW LEVEL JET AND A RIBBON OF ELEVATED MOISTURE. AS THESE ECHOES MOVE EAST THEY WILL MOVE AWAY FROM BOTH THESE COMPONENTS...SO AS THE RADAR SHOWS...THEY SHOULD DIE OUT. THERE IS A POSSIBILITY FOR A FEW SPRINKLES OVER WESTERN BENSON/ WESTERN TOWNER COUNTIES...BUT IT WILL MOST LIKELY BE VIRGA. BETTER CHANCES FOR CONVECTION WILL BE LATER THIS AFTERNOON...ALONG THE COLD FRONT. THIS FRONT IS CURRENTLY OVER THE NORTHWEST CORNER OF ND. LATEST MODELS ARE MOVING THIS FRONT EASTWARD A BIT QUICKER THAN THEY DID IN PRIOR RUNS. NOW IT APPEARS IT WILL BE INTO THE KDVL REGION BY LATE AFTERNOON AND ALONG A KROX/KGFK/VALLEY CITY LINE BY 06Z. RUC IS SHOWING THE LIFTED INDEX DROPPING TO AROUND -4/-6 BY 00Z ALONG THE FRONT. SFC MOISTURE RETURN SOMEWHAT LACKING...BUT THE RUC ALSO SHOWS GOOD MOISTURE AVAILABLE AT 850MB...SO IT WILL LIKELY BE HIGH BASED STORMS. NOT VERY GOOD DYNAMICS TO WORK WITH...BUT THE SFC CONVERGENCE WILL BE ENOUGH TO GENERATE SOME STORMS. WITH THE LACK OF UPPER SUPPORT...COVERAGE WILL NOT BE GREAT AND SEVERE STORMS ARE NOT EXPECTED. ADDED IN PCPN CHANCES FOR LATE AFTERNOON AND EARLY TONIGHT. && .PREV DISCUSSION... (ISSUED 425 AM CDT SUN AUG 20 2006) CURRENT OBSERVATIONAL OVERVIEW... 08Z SURFACE ANALYSIS DEPICTED THE COMMENCEMENT OF SOUTHERLY FLOW AND ASSOCIATED WAA FROM THE VALLEY WEST IN CONJUNCTION WITH IMPENDING S/W TROUGH FROM MANITOBA PROVINCE TO MONTANA. LATEST WATER VAPOR IMAGERY SHOWED WEST TO NORTHWEST FLOW ALOFT OVER THE NORTHERN PLAINS WITH EMBEDDED SHOTS OF S/W ENERGY RIDING ALONG IN FLOW. MOST PRONOUNCED S/W ATTM WAS EVIDENT OVER AB/SK PROVINCES WITH ATTENDANT 70KT SPEED MAX. SHORT TERM... MAIN FORECAST CHALLENGE DURING THE NEXT 24 TO 48 HOURS WILL BE TIMING AND DEGREE OF MOISTURE DEPTH FOR IMPENDING FROPA TO FEED OFF OF FOR CONVECTIVE POTENTIAL. LATEST MODEL TRENDS SUGGEST TIMING OF TROUGH PASSAGE WILL BE LATE TONIGHT FROM THE VALLEY WEST AND THEN EARLY MONDAY MORNING ACROSS MINNESOTA COUNTIES. BASED ON ABOVE TIMING APPEARS MAIN CONVECTIVE THREAT SHOULD BE ACROSS THE SOUTHERN PORTION OF CWFA WHERE SOME DAYTIME HEATING/ATMOSPHERIC DESTABILIZATION WILL OCCUR I.E. ML CAPES VALUES OF 1000 J/KG. BASED ON THIS WILL CONFINE LOW POP CHANCES FOR AREAS GENERALLY SOUTH OF A VALLEY CITY TO FARGO TO PARK RAPIDS LINE. IN WAKE OF TROUGH ANOTHER RIDGE OF HIGH PRESSURE WILL BRIEFLY BUILD INTO THE NORTHERN PLAINS MONDAY NIGHT INTO PART OF TUESDAY. EXPECT UNSETTLED CONDITIONS TO RETURN TO CWFA TUESDAY NIGHT AND WEDNESDAY AS LOW LEVEL FLOW BACKS TO SOUTHERLY COMPONENT ALLOWING MOISTURE/INSTABILITY TO OUR SOUTH TO MAKE A RETURN VISIT. SLOW NATURE TO TROUGH LEAVES MUCH UNCERTAINTY TO EVENTUAL OUTCOME FOR LATTER PART OF UPCOMING WEEK. ATTM GFS IS THE MOST BULLISH WITH STRENGTH OF TROUGH/ATTENDANT WAVE OF LOW PRESSURE THAT DEVELOPS ALONG BOUNDARY ON WEDNESDAY INTO THURSDAY. FOR NOW WILL TAKE CONSERVATIVE APPROACH WITH RESPECT TO DEGREE OF POPS/QPF POTENTIAL UNTIL OVERALL PICTURE BECOMES MORE CLEAR CUT. AS FOR TEMPS EXPECT GOOD MERCURY RECOVERY TODAY AFTER A COOL START WITH READINGS REACHING INTO THE LOW TO MID 80S. REMAINDER OF THE WEEK TEMPERATURES ARE A TOUGH CALL WITH TIMING ISSUES OF BOUNDARY INTERACTION/PASSAGE DETAILS RAISING QUITE A FEW QUESTIONS ATTM. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ GODON nd AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE ABERDEEN SD 746 AM CDT SUN AUG 20 2006 .UPDATE...REVISITED WX/POP GRIDS TO INCREASE AREAL COVERAGE WITH DEVELOPING CONVECTION ACROSS NORTH CENTRAL SODAK THIS MORNING...AS WELL AS TO REFRESH OVER HOURLY GRIDS. UPDATED WORDS/GRIDS OUT. DORN && .PREV DISCUSSION... (ISSUED 355 AM CDT SUN AUG 20 2006) SHORT TERM...TODAY THROUGH TUESDAY NIGHT WEST TO NORTHWEST UPPER LEVEL FLOW CONTINUES ACROSS THE REGION THROUGH MONDAY...WITH PRECIP CHANCES EXPECTED TODAY INTO MONDAY. WATER VAPOR IMAGERY SHOWING A WEAK WAVE EXITING NE WYOMING...WITH A FEW ISOLATED -TRW FIRING ACROSS NWRN SD. RUC/GFS/NAM INDICATE A DECENT THETA-E RIDGE SITUATED INTO WRN SD IN VICINITY OF THE CURRENT CONVECTION...WITH THIS RIDGE SHIFTING EASTWARD INTO CENTRAL SD BY MID MORNING. THEREFORE HAVE INSERTED AN ISOLATED -TRW MENTION FOR THIS MORNING ACROSS THE NORTH CENTRAL ZONES...EXPECTING ACTIVITY TO DISSIPATE BY MID/LATE MORNING. MOISTURE AXIS REMAINS IN THAT AREA THROUGH THE DAY...AS A STRONGER UPPER WAVE MOVES THROUGH LATER TODAY INTO MONDAY. LAPSE RATES INDICATING SUFFICIENT INSTABILITY...WITH MOISTURE STILL REMAINING AN ISSUE. LATEST SPC ANALYSIS SUGGESTS POTENTIAL FOR SEVERE ACTIVITY BUT EXPECT A LIMITED AMOUNT OF DEVELOPMENT DUE TO THE LACK OF MOISTURE. MODELS STILL HAVING TROUBLE COMING TO A CONSENSUS WITH THE COLD FRONT EXPECTED TO DROP THROUGH MONDAY INTO MONDAY NIGHT. LATEST HPC GUIDANCE SUGGESTING NAM MAY BE TOO FAST WITH THE FRONTAL BOUNDARY...AND GFS A LITTLE SLOW. AGREED WITH THIS...BUT ULTIMATELY LEANED TOWARD THE GFS FOR THE TIMING AS IT HAS SHOWN BEST CONTINUITY WITH THIS SYSTEM. THEREFORE CONTINUED WITH PRECIP CHANCES MONDAY INTO MONDAY AFTERNOON WITH THE FRONTAL PASSAGE...BUT OPTED TO REMOVE THE MENTION ACROSS THE NORTHERN CWA FOR MONDAY EVENING. WILL HAVE TO WATCH FUTURE MODEL TRENDS...TO FURTHER TREND PRECIP CHANCES FOR LATER MONDAY AFTERNOON INTO MONDAY NIGHT. BEGIN TO SEE SOME UPPER RIDGING ALOFT INTO TUESDAY AND TUESDAY NIGHT...WITH THE REGION BECOMING SANDWICHED BETWEEN SFC LOW PRESSURE TO THE WEST AND HIGH PRESSURE TO THE EAST. MODELS INDICATING SOUTHERLY FLOW INTO THE REGION...WITH A DECENT LLJ DEVELOPING TUESDAY NIGHT. CONTINUED WITH A MENTION OF PRECIP DURING THE MORE DIURNALLY FAVORED TIME OF TUESDAY NIGHT. HOWEVER IF THE HIGH PRESSURE AREA ENDS UP SLIGHTLY FURTHER WEST THAN MODELS CURRENTLY INDICATE...ANY ACTIVITY MAY REMAIN TO THE WEST OF THE CWA. AS FOR TEMPERATURES...MADE VERY LITTLE CHANGES. LONG TERM...WEDNESDAY THROUGH SATURDAY THE OPERATIONAL DATA SETS FOR THE 00Z GFS/EC WERE SIMILAR IN MASS FIELD OUTPUT AND REMAINED REFLECTIVE OF GOING EXTENDED FORECAST PACKAGE. THE 12Z/19 OPERATIONAL EC APPEARED TO BE AN OUTLIER IN ITS 500HPA HEIGHT FIELD ACROSS THE EASTERN PACIFIC AT 12Z ON SATURDAY...BUT THE 00Z/20 EC CAME IN LOOKING MORE SIMILAR TO THE GFS 500HPA HEIGHT FIELD FOR DAY 7. THIS LENT A LITTLE MORE CONFIDENCE TOWARD THE GFS ENSEMBLE SUITE OF PRODUCTS AS WELL AS THE OPERATIONAL GFS. BASICALLY...WEAK MID-LEVEL RIDGING ACROSS THE NORTH CENTRAL STATES WILL BE INTERRUPTED BY SHORT-WAVE TROFPAS WEDNESDAY AND FRIDAY...WITH THURSDAY AND SATURDAY EXPECTED ATTM TO BE DRY DAYS WITH WEAK SURFACE HIGH PRESSURE BUBBLES SEPARATING A COUPLE OF SURFACE LOW PRESSURE TROFPAS ASSOCIATED WITH EACH UPPER WAVE. NO SUBSTANTIVE CHANGE TO WX/POP GRIDS. DID EXTEND THE POP MENTION ON FRIDAY INTO FRIDAY EVENING ACROSS THE FAR EASTERN FORECAST AREA IN ANTICIPATION OF MODEL BIAS/TENDENCY TO SLOW THINGS DOWN A LITTLE AS FT=0 APPROACHES. AGAIN...LITTLE IN THE WAY OF CHANGE TO THE MAX/MIN T GRIDS AS...850HPA THERMAL PROGS POINTING TO WARMER CONDITIONS WEDNESDAY AND THURSDAY BEFORE STRONGER UPPER WAVE PASSES THROUGH ON FRIDAY DELIVERING A BLAST OF COOLER CANADIAN AIR TO THE NORTH CENTRAL STATES FOR FRIDAY AFTERNOON THROUGH SATURDAY NIGHT. 850HPA THERMAL PROGS TRANSITION FROM A RANGE OF +20C TO +28C DAYS 4 AND 5 DOWN INTO THE TEENS ON DAYS 6 AND 7. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ ALBRECHT/DORN sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MORRISTOWN TN 1000 AM EDT SUN AUG 20 2006 .DISCUSSION...SCATTERED SHOWERS AND THUNDERSTORMS HAVE MOVED ACROSS THE NORTHERN AND CENTRAL SECTIONS OF THE FORECAST AREA THIS MORNING WITH AN MCS MOVING INTO EASTERN KY ALONG AND JUST NORTH OF WEAK COLD FRONT AT THIS TIME. EXPECT MCS TO DECREASE IN INTENSITY BY THE TIME IT REACHES SW VA BUT THIS AREA HAS BEST CHANCE OF RAIN LATE THIS MORNING. EXTENSIVE CLOUDS AND SOME FOG ELSEWHERE IS KEEPING TEMPERATURES IN THE UPPER 60S TO MID 70S. THIS FRONT WILL BE THE FOCUS FOR SHOWERS AND THUNDERSTORMS TODAY AND WITH THE ATMOSPHERE VERY MOIST AND DAYTIME HEATING SOME LOCALIZED HEAVY RAINFALL MAY OCCUR. BEST FOCUS FOR HEAVY RAIN SHOULD STAY NORTHWEST OF THE CWA IN KY. LATEST RUC DATA SHOWS PRECIPITATION INCREASING LATE THIS MORNING AND CONTINUING THROUGH THE AFTERNOON. THE GFS/NAM GENERALLY SHOW THIS TOO WITH SHOWERS AND THUNDERSTORMS DEVELOPING NORTHERN AREAS FIRST AND SOUTHERN AREAS THIS AFTERNOON. WILL CONTINUE HIGH POPS AND RAISE THEM SLIGHTLY FOR LATE MORNING AND AFTERNOON HOURS. ALSO ADJUSTING HOURLY TEMPERATURES AND DEWPOINTS. && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ TD tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 200 PM MDT SUN AUG 20 2006 .SHORT TERM... (TONIGHT - WEDNESDAY) FORECAST PROBLEM WILL BE CHANCES OF PRECIPITATION TONIGHT AND MONDAY...MAINLY SOUTH OF INTERSTATE 70. WATER VAPOR IMAGERY SHOWS THAT THE SOUTHERN AND CENTRAL HIGH PLAINS STILL UNDER A MOIST TROPICAL FLOW IN MID/UPPER LEVELS OF THE ATMOSPHERE. LOWER LEVELS ALSO QUITE MOIST AFTER A COUPLE OF DAYS OF UPSLOPE FLOW. IT WILL NOT TAKE MUCH FORCING TO LIFT THIS VERY BUOYANT AND MOIST COLUMN. AREA WILL BE UNDER PERSISTENT RIGHT REAR QUADRANT OF UPPER JET STRETCHING ACROSS THE MIDWEST. IN ADDITION...SHORTWAVE TROUGH CURRENTLY OVER NEW MEXICO EXPECTED TO TRACK NORTH THEN NORTHEASTWARD THE NEXT 24 HOURS. IT SHOULD BE SUFFICIENT TO INITIATE SHOWERS AND A FEW THUNDERSTORMS. QUESTION WILL BE HOW FAR NORTH TO TAKE THE QPF. CERTAINLY AREAS SOUTH OF THE INTERSTATE STAND THE BEST CHANCES. THE HIGHER RESOLUTION MODELS (NAM12 AND RUC13) ARE ALSO THE MOST AGGRESSIVE WITH TAKING THE PRECIPITATION NORTH ON MONDAY. PRECIPITATION WILL WIND DOWN LATE MONDAY AFTERNOON AND EVENING AS SHORTWAVE TROUGH PULLS AWAY AND RIDGING REBUILDS FROM THE NORTHWEST. REMAINDER OF THE SHORT TERM PERIOD WILL BE DOMINATED BY UPPER RIDGING. NOT MUCH CHANGE FORECAST IN 850MB TEMPERATURES BETWEEN MONDAY AND TUESDAY...BUT BY WEDNESDAY THEY ARE FORECAST TO APPROACH 30C AS UPPER ANTICYCLONE NEARLY OVERHEAD. THIS WILL ALLOW TEMPERATURES TO RISE WELL INTO THE 90S BY MIDWEEK. .LONG TERM... (THURSDAY - SUNDAY) PATTERN WILL FEATURE UPPER RIDGING OVER THE FOUR CORNERS. LATEST MODEL RUNS ARE STRONGER WITH RIDGING EXTENDING ACROSS THE ROCKIES AND INTO THE CENTRAL PLAINS. AS A RESULT...TEMPERATURES WILL WARM AND BE WELL ABOVE NORMAL THROUGH THE END OF THE WEEK. STRONG NORTHERN STREAM SHORTWAVE TROUGH WILL MOVE ACROSS THE NORTHERN ROCKIES EARLY IN THE PERIOD...EJECTING INTO THE NORTHERN PLAINS FRIDAY. THIS WILL SUPPORT A SURFACE COLD FRONT WHICH IS FORECAST TO MOVE THROUGH THE LOCAL FORECAST AREA FRIDAY AFTERNOON/NIGHT. EXPECT A CHANCE OF THUNDERSTORMS WITH THE FRONT. POST FRONTAL LOW LEVEL UPSLOPE REGIME WILL RULE ON SATURDAY...WHICH PROBABLY MEANS A COOL AND CLOUDY DAY. RIDGING QUICKLY REBUILDS ALOFT BEHIND THE SHORT WAVE...AND WARMING WILL COMMENCE ON SUNDAY. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ JDK ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON KY 400 PM EDT SUN AUG 20 2006 .DISCUSSION... NAM SEEMED TO BE HANDLING CURRENT SYNOPTIC PATTERN FAIRLY WELL...SO WENT WITH THE LATEST NAM SOLUTION FOR SHORT TERM PORTION OF FORECAST. GFS AND NAM BOTH WITH SIMILAR SOLUTIONS...MOVING THE FRONT A BIT FURTHER SOUTH THAN WHERE IT IS CURRENTLY LOCATED. WITH THIS IN MIND...DECIDED TO SLOW DOWN SOUTHWARD PROGRESSION OF FRONT A BIT...TO BETTER REFLECT CURRENT FRONTAL POSITION AND MOVEMENT. ALL MOS DATA...MAV...MET...AND FWC...COMING IN WITH VERY LOW OR NO PRECIPITATION CHANCES AT ALL THROUGH WEDNESDAY NIGHT. DECREASED PRECIP CHANCES QUITE A BIT FOR ENTIRE SHORT RANGE PORTION OF FORECAST. LEFT IN SLIGHT CHANCE POPS FOR SOUTHERN AND SOUTHEASTERN TWO TIERS OF COUNTIES FOR THE NEXT FEW DAYS...AS IT APPEARS A WEAK WAVE WILL FORM AND MOVE EASTWARD ALONG A NEARLY STATIONARY FRONTAL BOUNDARY...PARTICULARLY TUESDAY AND TUESDAY NIGHT. WITH THIS IN MIND...WENT CLOSEST TO MAVMOS FOR POPS. GRADUALLY DECREASED CLOUD COVER THROUGH THE PERIOD...PER LATEST NAM AND GFS SOLUTIONS. MODEL CROSS SECTIONS ALSO DEPICTING VERY LITTLE MOISTURE IN LOW LEVELS OF ATMOSPHERE FOR THE NEXT 3 DAYS...SO THIS CHANGE SEEMED WARRANTED. DEWPOINTS SEEMED A BIT TOO HIGH...AS HIGH PRESSURE SHOULD BE MOVING IN FROM THE NORTH OVER THE NEXT COUPLE OF DAYS...AS PER THE LATEST ENSEMBLE MODEL OUTPUT. TEMPERATURES WERE IN FAIRLY GOOD SHAPE ALREADY. A FEW SLIGHT TWEAKS WERE MADE HERE AND THERE TO ACCOUNT FOR THE SLIGHTLY WARMER DAYTIME HIGHS SHOWING UP IN THE LATEST MOS DATA. USED A BLEND BETWEEN MRF ENSEMBLE TEMPS AND MAV/MET MOS FOR HIGHS...GOING A BIT WARMER THAN PREVIOUSLY FORECAST THROUGH WEDNESDAY AFTERNOON. OVERNIGHT LOWS LOOKED A BIT WARM AND WERE DECREASED SLIGHTLY. OVERALL TEMPERATURE FORECAST WAS ALREADY IN VERY GOOD SHAPE. WINDS WERE TWEAKED A BIT TO BETTER REFLECT TERRAIN AFFECTS...ESPECIALLY DURING THE NIGHTTIME PERIODS. QPF AND WEATHER GRIDS WERE ALSO CHANGED TO REFLECT CHANGES MADE TO SKY AND POP FORECAST. EXTENDED (0Z THU THROUGH 12Z MON)...OPTED FOR THE 0Z GFS ENSEMBLES. ECMWF HAS MORE RIDGING OVER THE SOUTHERN US AND HIGHER HEIGHTS ACROSS THE AREA THROUGH MUCH OF THE EXTENDED PERIOD. EARLY IN THE PERIOD...HEIGHTS RISE...WITH A RETURN OF A WARM AND MOIST AIRMASS AS SFC HIGH SHIFTS EAST...AND RETURN FLOW SETTING UP ON FRI. ABOVE NORMAL TEMPERATURES ARE EXPECTED THUR THROUGH SAT WITH 8H TEMPS IN THE UPPER TEENS C...AND RAISED MAX TEMPS SLIGHTLY THESE DAYS FROM THE PREVIOUS FORECAST. MIN TEMPS WILL BE LOWEST EARLY IN THE PERIOD AS SFC HIGH SHIFTS EAST ON THU AM WITH PROBABLE RIDGE/VALLEY TEMP SPLIT SETUP. INTRODUCED SLIGHT CHANCE POPS ON FRI...MAINLY DIURNAL THOUGH ENSEMBLES INDICATE THAT A SW/V TROUGH MAY BE CROSSING THE REGION ON FRI. MAIN TROUGH WILL PROGRESS EAST FROM THE NORTHERN ON FRI TO ONTARIO BY THE END OF THE PERIOD. SFC LOW SHOULD ACCOMPANY THIS SYSTEM WITH SFC COLD FRONT APPROACHING THE AREA LATE IN THE PERIOD. DEPENDING ON THE STRENGTH OF THE RIDGE OVER THE SOUTHEASTERN US (ECMWF IS STRONGER THAN GFS/ENSEMBLES) THIS FRONT COULD BE SLOWER. INCLUDED CHANCE POPS FROM SAT PM THROUGH SUN EVENING...DURING TIME THE FRONT IS EXPECTED TO MOVE THROUGH THE AREA. && .PREV DISCUSSION... 1101 AM EDT SUN AUG 20 2006 PRIMARY FORECAST PROBLEM FOR UPDATE IS TEMPERATURES FOR THE REST OF TODAY. WITH THE PASSAGE OF THIS MORNINGS MCS...HOURLY TEMPERATURES AT SEVERAL SITES ACROSS FORECAST AREA ARE NOW SEVERAL DEGREES LOWER THAN PREVIOUSLY FORECAST. WITH THIS IN MIND...DECIDED TO DECREASE AFTERNOON HIGH TEMPERATURES ACROSS THE BOARD TO A CATEGORY BELOW PREVIOUS FORECAST. ALSO REMOVED MENTION OF FOG FROM FORECAST...AS WINDS FROM MCS PASSAGE HAVE HELPED TO BREAK UP QUITE A BIT OF THE FOG THAT WAS PRESENT IN VALLEY LOCATIONS THIS MORNING. REST OF FORECAST WAS IN GOOD SHAPE. 430 AM EDT SUN AUG 20 2006 COLD FRONT HAS DROPPED INTO THE NORTHERN PORTIONS OF OUR CWA THIS MORNING. A THIN LINE OF SCATTERED SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ALONG THE BOUNDARY...WITH A FEW ADDITIONAL POCKETS OF SHOWER AND THUNDERSTORMS OUT AHEAD OF THE FRONT. OTHERWISE...AN MCS WAS TRACKING EASTWARD THROUGH WESTERN KENTUCKY. EXPECT THIS FEATURE TO WEAKEN SOME AS IT PROGRESSES EASTWARD INTO A MORE STABLE ENVIRONMENT AND WHERE THE ATMOSPHERE HAS BEEN WORKED OVER DURING THE OVERNIGHT. RUC ANALYSIS AND RADAR CONFIRMS THIS TREND. EXPECT SHOWERS AND THUNDERSTORMS TO CONTINUE TO DEVELOP ALONG AND AHEAD OF THE FRONT AS IT SLIDES SOUTHWARD THROUGH THE DAY. ACTIVITY WILL INTENSIFY IN COVERAGE AND STRENGTH LATER IN THE AFTERNOON WITH HELP OF DAY TIME HEATING AND AS SOME SHORT WAVE ENERGY MANAGES TO MAKE ITS WAY INTO THE AREA. PERSISTENCE WOULD SUGGEST THAT ONE OR TWO STORMS MAY EVEN MAKE IT TO SEVERE LEVELS THIS AFTERNOON WITH THE MAIN THREAT BEING HIGH WINDS. ALSO...SOME LOCALLY HEAVY RAINFALL WILL BE POSSIBLE. WILL MENTION THESE IN THE HWO. WILL SEE A BRIEF REPRIEVE FROM SHOWER ACTIVITY LATER TONIGHT. AFTERWARDS...MODELS STILL DEVELOP A WAVE OF LOW PRESSURE AND TRACK IT EASTWARD BETWEEN THE TN AND OH VALLEYS LATE MONDAY INTO TUESDAY. NAM IS FURTHER SOUTH AND FASTER WITH ANY ENERGY ASSOCIATED WITH THIS DISTURBANCE AS COMPARED TO THE GFS. FOR NOW STAYED WITH THE MORE CONSISTENT GFS SOLUTION. BEST LIFT OVER EASTERN KENTUCKY APPEARS TO OCCUR DURING THE MONDAY NIGHT...TUESDAY TIME FRAME. SO HIT POPS HARDEST DURING THIS PERIOD. 930 PM EDT SAT AUG 19 2006 S/WV HAS MOVED THRU THE AREA AND MOST OF THE CONVECTION NOW EAST/SOUTH OF CWFA. ISOLATED CONVECTION POPPING UP IN CNTRL KY BUT DIMINISHES TO BARELY -RA BY THE TIME IT GETS TO I-75. WX OF GREATEST CONCERN IS THE SHRA ALONG THE QUASI-STATIONARY FNT FM PMH TO CVG AND CONVECTIVE COMPLEX ON THE WRN FRINGE OF CNTRL KY CWFA. HAVE KEPT CHC POP IN NORTH FOR FNTL CONVECTION AND FEEL THE MCS IN WRN KY WILL HOLD AT BAY UNTIL AFTER SUNRISE. LOCALLY DENSE FOG IN VLYS IS SPILLING ONTO RIDGES IN LIGHT SRLY BREEZE. LIGHT WIND SHOULD GO CALM TONITE AND FOG WILL SETTLE BUT THE DEPTH OF THE MOIST/SATURATED AIR MAY PRECLUDE ANY SIGNIFICANT DROP IN TEMP. ALREADY INTO THE LOWER 70S AND HAVE PROJECTED LOWS IN THE NRN 2/3 CWFA TO ONLY DROP A COUPLE OF DEG FROM CURRENT TEMPS...PUTTING THEM BARELY INTO THE UPPER 60S. && .JKL WATCHES/WARNINGS/ADVISORIES...NONE. && $$ AR/JP ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 347 PM EDT SUN AUG 20 2006 .DISCUSSION... MAIN FORECAST CONCERN IS RAIN CHANCES FOR TOMORROW. CURRENT WEATHER...19Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED A GENERAL NW FLOW ALOFT ACROSS THE NORTHERN HALF OF THE U.S. AND INTO CANADA. WITHIN THE FLOW...FEATURES OF INTEREST ARE A WEAK RIDGE MOVING INTO UPPER MICHIGAN AT THE MOMENT AND STRONG SHRTWV TROUGH DROPPING SOUTHWARD THROUGH SASKATCHEWAN AND MANITOBA. THE UPPER RIDGE THAT IS BUILDING INTO THE CWA IS RESULTING IN LOW TO MID LEVEL SUBSIDENCE (SEE 12Z MPX AND GRB SOUNDINGS WITH INVERSION AT 800MB)...HELPING TO MAINTAIN A HIGH PRESSURE RIDGE OVER THE AREA AND KEEP SKIES OVERALL MOSTLY SUNNY. THESE MOSTLY SUNNY SKIES HAS RESULTED IN DEEP MIXING UP TO THE SUBSIDENCE INVERSION...AND SINCE TEMPS AT 800MB ARE AROUND 9C...SURFACE TEMPERATURES HAVE CLIMBED TO NEAR 80 AWAY FROM LAKE BREEZES. THE MIXING HAS ALSO ALLOWED DEWPOINTS TO DROP INTO THE MID 40S IN THE INTERIOR. HIGHER DEWPOINTS CAN BE SEEN OFF TO THE WEST ACROSS WESTERN MINNESOTA AND THE DAKOTAS. THIS MOISTURE IS ALONG AND AHEAD OF A COLD FRONT ASSOCIATED WITH THE STRONG SHRTWV TROUGH...WHICH EXTENDS FROM A LOW IN NE MANITOBA SOUTHWESTWARD TO THE BISMARCK AREA. A FEW SHOWERS AND THUNDERSTORMS ARE ALSO OCCURRING ON THE FRONT IN NORTH DAKOTA AS NOTED BY REGIONAL RADARS. TONIGHT...UPPER LEVEL RIDGE OVER THE AREA IS PROGGED TO PUSH EASTWARD IN RESPONSE TO THE SHRTWV TROUGH IN SASKATCHEWAN MOVING EASTWARD. ALTHOUGH HEIGHTS WILL BE FALLING AND WARM ADVECTION IS EXPECTED TO CONTINUE AHEAD OF THE TROUGH...ISENTROPIC LIFT IS PROGGED TO BE MINIMAL. SO NO GREAT INCREASE IN CLOUD COVER IS EXPECTED UNTIL THE MAIN FRONTAL BOUNDARY MOVES INTO THE MN ARROWHEAD DURING THE LATE PART OF THE NIGHT. THEREFORE...WITH MOSTLY CLEAR SKIES AND GENERALLY LIGHT WINDS (PARTICULARLY CENTRAL AND EAST)... TEMPERATURES DROPPING AT LEAST INTO THE UPPER 40S AS INDICATED BY THE MAV COOP GUIDANCE SEEMS LIKELY. DUE TO THE COOL READINGS...HAVE INSERTED SOME PATCHY FOG FOR THE INLAND AREAS OF THE CENTRAL AND EASTERN CWA. WARMER TEMPERATURES ARE EXPECTED ALONG THE GREAT LAKES WITH A COMBINATION OF WEAK SURFACE RETURN FLOW AND LAND BREEZES. MONDAY...UPPER LEVEL SHRTWV TROUGH IS PROGGED TO CONTINUE MOVING EASTWARD...CROSSING ALL OF NORTHERN ONTARIO DURING THE DAY. THEREFORE THE BETTER DYNAMICAL FORCING IS EXPECTED TO THE NORTH. HOWEVER...THERE MAY STILL BE A FEW SHOWERS OR THUNDERSTORMS DURING THE MORNING MOVING INTO THE WESTERN U.P. FROM MINNESOTA...SO HAVE MAINTAINED THE SLIGHT CHANCE POPS. SUNSHINE THAT OCCURS IN THE MORNING AHEAD OF THE FRONT IN THE AFTERNOON SHOULD BE ENOUGH TO LIFT TEMPERATURES INTO THE LOW 80S (MIXING TO 850MB AND PER MET/MAV GUIDANCE TEMPS). THESE TEMPERATURES COMBINED WITH DEWPOINTS AROUND 60F WILL RESULT IN MIXED LAYER CAPE OF 1000-1500 J/KG AHEAD OF THE FRONT WITH LITTLE CIN. LAKE BREEZES COMBINED WITH SOME WEAK LOW LEVEL FORCING ALONG THE FRONT IS EXPECTED TO BE ENOUGH TO DEVELOP SOME MORE ISOLATED-SCATTERED THUNDERSTORMS DURING THE AFTERNOON... PARTICULARLY INLAND FROM LAKE SUPERIOR. 0-6KM SHEAR IS AROUND 35 KNOTS...SO ANY STORMS THAT DO DEVELOP SHOULD ORGANIZE INTO AT LEAST MULTICELLS. LOW WET BULB ZERO HEIGHTS (9500 FT OR BELOW) COMBINED WITH SURFACE TO 5000 FT THETA-E DIFFERENCES OF 20-25C SUGGESTS BOTH LARGE HAIL AND DAMAGING WINDS ARE A POSSIBILITY. THE ONLY OTHER ITEM TO NOTE IS THE DRY SLOT BEHIND THE FRONT. MODELS SUGGEST DEEP MIXING OCCURRING WITHIN THE DRY SLOT...ALLOWING AREAS SUCH AS IRONWOOD TO MIX TO 800MB. THIS WILL RESULT IN DEWPOINTS FALLING INTO THE UPPER 40S. IN ADDITION...WINDS SHOULD INCREASE WITH THE DEEP MIXING...AND HAVE WINDS FORECAST NEAR 20KT FOR HOUGHTON WITH THE PREFERRED WESTERLY FLOW. MONDAY NIGHT AND TUESDAY...GFS/NAM/UKMET SUGGEST THE POSSIBILITY OF A SECONDARY SURFACE COLD FRONT MOVING INTO UPPER MICHIGAN AFTER MIDNIGHT MONDAY NIGHT BEFORE HIGH PRESSURE OVER NW ONTARIO BUILDS OVER THE CWA ON TUESDAY. THIS SECONDARY COLD FRONT APPEARS TO BE ASSOCIATED WITH SOME STRATOCUMULUS CLOUDS...AND WITH NE WINDS BEHIND IT...SEE NO REASON WHY AT LEAST A SCATTERED MVFR DECK WILL DEVELOP OVER THE U.P. BEFORE GRADUALLY MIXING OUT ON TUESDAY. UNTIL THIS CLOUD DECK ARRIVES...DIMINISHING WINDS MONDAY NIGHT WITH A SLACKENING PRESSURE GRADIENT AND PRECIPITABLE WATER BETWEEN 0.5-0.75 INCHES SUGGESTS TEMPERATURES SHOULD DROP INTO THE UPPER 40S AGAIN IN THE INTERIOR CENTRAL. 850MB TEMPS OF 6-8C ON TUESDAY WILL RESULT IN COOLER READINGS THAN EXPERIENCED TODAY AND MONDAY...AND WITH NORTHERLY WINDS...LOCATIONS ALONG LAKE SUPERIOR MAY NOT GET ABOVE 70. INTERIOR LOCATIONS ALONG THE WISCONSIN BORDER SHOULD STILL REACH THE MID 70S...THOUGH. TUESDAY NIGHT AND WEDNESDAY...MODELS HAVE COME INTO BETTER AGREEMENT DURING THIS PERIOD AND MATCHES UP WELL WITH THE PREVIOUS FORECAST. HIGH PRESSURE WHICH WAS OVER THE CWA ON TUESDAY WILL HEAD EAST IN RESPONSE TO UPPER LEVEL FLOW TURNING ZONAL. THIS ZONAL FLOW WILL ALSO INDUCE PRESSURE FALLS ACROSS THE NORTHERN PLAINS AND THEREFORE A LOW LEVEL JET DOWNSTREAM OVER THE UPPER MISSISSIPPI VALLEY. MOST MODELS INDICATE THAT AFTER MIDNIGHT TUESDAY NIGHT...AN MCS IS PROGGED TO DEVELOP BY NEARLY ALL MODELS OVER THE NORTH HALF OF MINNESOTA. THIS MCS WILL LIKELY WEAKEN SOME AS IT MOVES EAST WEDNESDAY INTO THE DEPARTING HIGH PRESSURE AREA...BUT AT LEAST CHANCE POPS FOR SHOWERS AND THUNDERSTORMS ARE REQUIRED. AREAS IN THE WESTERN U.P. MAY NEED TO BE BUMPED UP TO LIKELY OR HIGHER IF THE CURRENT AGREEMENT CONTINUES SINCE THAT APPEARS TO BE THE BEST AREA TO GET RAIN. UNTIL THE MCS ARRIVES...SKIES ARE LIKELY TO REMAIN MOSTLY CLEAR FOR MUCH OF THE NIGHT. GIVEN THAT THE AIRMASS WILL STILL BE DRY AND WINDS ON THE LIGHT SIDE...TEMPERATURES SHOULD EASILY DROP INTO THE 40S AS INDICATED BY MAV COOP GUIDANCE. TEMPERATURES ARE A BIT MORE DIFFICULT TO PIN DOWN FOR WEDNESDAY GIVEN THE EXPECTED RAINFALL AND PLENTY OF CLOUD COVER. HAVE WENT CLOSER TO CLIMATOLOGY...THOUGH IF MORE PRECIPITATION COVERAGE OCCURS...TEMPERATURES MAY NOT GET ABOVE 70 IN MOST LOCATIONS. EXTENDED (THURSDAY THROUGH SUNDAY)...MODEL AGREEMENT AMONGST THE OPERATIONAL AND ENSEMBLE MODEL RUNS IS LESS THAN AVERAGE AT THE BEGINNING OF THE PERIOD...THEN COMES BACK TOGETHER TOWARDS THE WEEKEND. 06Z GFS AND 00Z ECMWF/UKMET ALL INDICATE SOME SHRTWV MOVING THROUGH UPPER MICHIGAN AT THE BEGINNING OF THE PERIOD...BUT THE TIMING VARIES FROM THURSDAY (06Z GFS) TO FRIDAY (00Z ECMWF/UKMET). FOR NOW...PREFER TO FOLLOW THE MORE CONSISTENT GFS RUNS WHICH ALLOWS FOR THUNDERSTORMS ON THURSDAY...A BRIEF PERIOD OF QUITE WEATHER AFTER MIDNIGHT THURSDAY NIGHT AND THEN MORE WARM ADVECTION WHICH MAY RESULT IN MORE RAIN ON FRIDAY. FOR FRIDAY NIGHT THROUGH SUNDAY... MODELS INDICATE A FAIRLY SIGNIFICANT SHRTWV TROUGH MOVING FROM WESTERN CANADA ON THURSDAY AND ACROSS THE CWA LATE SATURDAY. HAVE MAINTAINED A CHANCE OF THUNDERSTORMS FOR THE APPROACHING COLD FRONT FOR FRIDAY NIGHT INTO SATURDAY EVENING...THEN CLEARING SKIES FOR SUNDAY AS HIGH PRESSURE AND SUBSIDENCE BUILDS IN BEHIND THE SHRTWV TROUGH. TEMPERATURES THROUGH THE PERIOD WILL ALL DEPEND ON THE AMOUNT OF CONVECTION THAT OCCURS. IT APPEARS THAT THURSDAY WILL BE COOL WITH EASTERLY LOW LEVEL WINDS...BUT THEN WARMER CONDITIONS FRIDAY AND SATURDAY AHEAD OF THE SHRTWV TROUGH (GFS SHOWS 850MB TEMPS CLIMBING TO 16C). 850MB TEMPS THEN COOL TO 8-10C BEHIND THE TROUGH...SO SURFACE TEMPERATURES WILL END UP COOLER ON SUNDAY. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ AJ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 110 PM EDT SUN AUG 20 2006 .AVIATION... LINGER CU FIELD HAS MIXED OUT OF FNT AND LIFTED TO VFR AT DTW/DET. LITTLE ADDITIONAL DEVELOPMENT EXPECTED THIS AFTERNOON GIVEN THE AMOUNT OF DRY AIR AND LOWERING SUBSIDENCE INVERSION NOTED ON 15Z/16Z TAMDAR SOUNDINGS. SURFACE GRADIENT IS ALREADY BEGINNING TO SLACKEN AS HIGH OVER IOWA/WISCONSIN BUILDS TOWARD LOWER MICHIGAN...WITH STATIONS BEGINNING TO LOSE THEIR GUSTINESS. EXPECT CLEAR SKIES/CALM WINDS OVERNIGHT. THERE WAS A WIDE RANGE OF FOG REPORTS UNDER THE SURFACE HIGH UPSTREAM LAST NIGHT...FROM NOTHING OR SHALLOW MIFG TO A QUARTER MILE. HOWEVER THE AIRMASS HAS ALREADY DRIED OUT QUITE A BIT ACROSS SOUTHEAST MICHIGAN...WITH DEWPOINTS MIXED DOWN INTO THE LOW 50S AS OF 16Z...WHICH ARE A GOOD 5-10F LOWER THAN THE AREAS UPSTREAM THAT SAW FOG LAST NIGHT. CANNOT DISCOUNT THE POTENTIAL ALL TOGETHER AS WE WILL BE ABLE TO RADIATE QUITE WELL...AND EVEN THE GFS HAS SURFACE CONDENSATION PRESSURE DEFICITS BELOW 20MB. HOWEVER WILL TRIM BACK THE TIMING BY A FEW HOURS...ONLY CARRYING 5SM BR FROM 10Z TO 13Z. && .PREV DISCUSSION...ISSUED 1037 AM EDT SUN AUG 20 2006 UPDATE... VIS SATELLITE SHOWS THE EARLY MORNING LOW CLOUDS ARE RAPIDLY STRIPPING AWAY...WITH THE SAGINAW VALLEY ALREADY SUNNY. CLOUDS ARE HOLDING LONGER ACROSS THE THUMB WITH SOME HELP WITH THE UNSTABLE NORTHERLY FLOW OFF LAKE HURON...HOWEVER EVEN THE BACK EDGE OF THE CLOUDS OUT ACROSS THE OPEN LAKE IS STEADILY DROPPING SOUTHWARD. 12Z DTX/APX SOUNDINGS SHOW THE STORY...WITH DTX SATURATED BELOW 850MB WHILE APX BEGINS TO DRY OUT JUST ABOVE THE SURFACE. 12Z RUC/NAM TEMPERATURE/DEWPOINT PROFILES STILL SUPPORT SOME CU DEVELOPMENT TODAY...WITH DEWPOINTS IN THE UPPER 50S AND 850MB TEMPERATURES AROUND 9C. HOWEVER GIVEN THE STRONG SUBSIDENCE AND DRYING BEHIND THE SHORTWAVE DOWNSTREAM OVER SOUTHWEST ONTARIO...DO NOT EXPECT THESE CLOUDS TO PERSIST VERY LONG. WILL UPDATE TO ADJUST SKY COVER GIVEN THE CLEARING THAT HAS ALREADY DEVELOPED. WILL CARRY DRIZZLE OF LIGHT SPRINKLES FOR A COUPLE MORE HOURS ACROSS THE EASTERN CWA AS RADAR/SATELLITE STILL INDICATE SOME WEAK ACTIVITY DOWNSTREAM OF LAKE HURON. PREV DISCUSSION...ISSUED 456 AM EDT SUN AUG 20 2006 MARINE... DECIDED TO ADD INNER SAGINAW BAY TO SMALL CRAFT ADVISORY TODAY...AS LATEST RUNNING OF THE WAVE MODEL BRINGS CRITERIA FOR WAVES INTO THE INNER PART OF THE BAY AS WINDS TURN TO EAST OF NORTH. WATCHES/WARNINGS/ADVISORIES SECTION BELOW ALSO UPDATED. PREV DISCUSSION...ISSUED 354 AM EDT SUN AUG 20 2006 SHORT TERM...TODAY AND TONIGHT BROAD SURFACE/LOW LEVEL CYCLONIC FLOW LINGERING OVER SOUTHEAST MI THIS MORNING...GIVING WAY TO HIGH PRESSURE BUILDING IN FROM THE WEST AND SETTLING OVERHEAD TONIGHT. MEANWHILE AT 500 MB...EASTERN GREAT LAKES SHORTWAVE TROUGH CONTINUING EAST TODAY WITH SHORTWAVE RIDGING SETTING UP OVER FORECAST AREA TODAY AND CONTINUING TONIGHT. MOISTURE IN MID TO UPPER LEVELS VERY SPARSE AS PER MODEL CONSENSUS AND WATER VAPOR IMAGERY...EXPECTED TO REMAIN SO THROUGH TONIGHT. LOW LEVEL MOISTURE IS MORE PROBLEMATIC. QUITE OF BIT OF LOW MOISTURE...SUCH AS AT 925 MB...AROUND THIS MORNING...BUT GFS MUCH FASTER DIMINISHING THIS MOISTURE THAN IS NAM/LOCAL WRFHEMI/NGM. MODEL SOUNDINGS ALSO SHOW THIS. GIVEN VEERING FLOW WITH MOIST AIR TRAJECTORIES OFF OF LAKE HURON...AM LEANING MORE TOWARD THE DELAYED DEPARTURE OF LOW CLOUDS...AND THUS CLOUDS ONLY GRADUALLY DIMINISHING THROUGH THE DAY. ALSO...AWIPS NAM CUMULUS RULE PROMISES BROKEN DIURNAL CLOUD DEVELOPMENT. FAR SOUTHERN COUNTIES SHOULD SEE THE LEAST CLOUD COVER...AS PER CLOUD ADVECTION/DEVELOPMENT TREND ACROSS THE AREA SINCE MIDNIGHT. GENERAL LOW TO MID LEVEL SUBSIDENCE THROUGH TONIGHT AS PER QVECTOR FIELDS AND DESCENT SEEN ON 300K/305K ISENTROPIC SURFACES. TEMPERATURES TODAY TENDING TO BE A FEW DEGREES COOLER THAN YESTERDAY...IN AGREEMENT WITH T1 GUIDANCE TRENDS. ALSO NOTICEABLY LESS HUMID TODAY THAN YESTERDAY...AS SURFACE DEW POINTS ARE EXPECTED TO BE ABOUT 10 DEGREES LOWER TODAY. WITH LIGHT WINDS AND SURFACE HIGH PRESSURE RIGHT OVERHEAD TONIGHT...WILL RETAIN PATCHY FOG MENTION. SOME PATCHES OF FOG/MIST CURRENTLY SEEN WITH UPSTREAM HIGH. LONG TERM...MONDAY THROUGH SATURDAY JUST WHEN NUMERICAL SUITE WAS BEGINNING TO SHOW SOME SIGNS OF STABILITY...THIS MORNINGS COMPUTATIONS SHOW OTHERWISE. CULPRITS ARE INITIALIZATIONS OF WAVES FROM ALASKA DOWN TO 40N BETWEEN 150-140W AND THE IMPACT OF THESE WAVES WITH CONVECTIVE FEEDBACK SIGNALS FOR THE MID WEEK PERIOD. THE GFS SEEMS TOO AGGRESSIVE BREAKING DOWN THE RIDGE ACROSS THE GREAT LAKES WITH STRONG CONVECTIVE DEVELOPMENT OVER THE PLAINS THEN TRACKING ITS ELEMENTS EAST WHILE THE ECMWF/UKMET/CANADIAN/WRF-HEMI LOOK MORE REASONABLE BUT THESE TOO HAVE COMPLICATIONS WITH OVERALL CONVECTIVE TRENDS FOR THE UPCOMING WEEK. AS EXPECTED...WESTERLIES WILL BE ACTIVE THIS WEEK WITH LEAD SHORT WAVE APPROACHING LAKE WINNIPEG THIS MORNING WILL REMAIN WELL NORTH OF THE LOCAL AREA MONDAY THROUGH TUESDAY. ASSOCIATED COLD FRONT WILL APPROACH THE LOWER LAKES LATE MONDAY NIGHT INTO TUESDAY WITH LITTLE IN THE WAY OF MOISTURE OR UPPER SUPPORT. NEVERTHELESS...TIMING OF THIS FRONT DOES MOVE IT THROUGH DURING THE PEAK HEATING ON TUESDAY AND THIS PUSHES CAPES TO BETWEEN 1000-1500 J/KG WITH MID LEVEL LAPSE RATES OF 6.5 C/KM. CURRENT FORECAST FOR CHANCE OF SHOWERS AND SLIGHT CHANCE FOR THUNDER LOOKS GOOD AT THIS TIME WITH NO CHANGES. WITH FROPA...ALBEIT SLOWER MIGRATION SOUTHWARD...TUESDAY NIGHT COULD SEE LINGERING CONVECTION BEFORE DISSIPATING WITH LOSS OF THE SUNSHINE AND WEAKENING SURFACE CONVERGENCE. THE QUESTION WILL BE JUST HOW MUCH COLD ADVECTION OCCURS OVER LAKE HURON OVERNIGHT. THE NMM SUGGESTS LAKE EFFECT RAIN SHOWERS WITH 1000-850MB LAPSE RATES OVER 7.5 C/KM WITH THE OTHER VARIOUS MODELS NOT ONLY WARMER BUT LESS PRONOUNCED WITH THERMAL TROUGH OVER LAKE HURON. AS THE NMM RESOLUTION IS HIGHER AND IT MORE MESOSCALE THAN ITS COUNTERPARTS...PREFER TO INTRODUCE A SLIGHT CHANCE FOR RAIN SHOWERS OVERNIGHT FOR SOUTH LAKE HURON AND INCLUDE HURON COUNTY. SURFACE HIGH SLIDES INTO THE GREAT LAKES FOR WEDNESDAY THEN UPSTREAM CONVECTIVE TRENDS WILL DICTATE THE REMAINDER OF THE FORECAST. AS NOTED IN THE SWODY3 AND CURRENT ECMWF...HEIGHT FALLS WILL COMMENCE WITH THE APPROACH OF VORTEX IN THE GULF OF ALASKA TRACKING JUST NORTH OF THE U.S. BORDER. LEE SURFACE CYCLOGENESIS WILL NOT ONLY INCREASE THE LOW LEVEL JET BUT MOISTURE TRANSPORT AND INCREASED SHEAR FOR SEVERAL COMPLEXES TO DEVELOP. WHILE THE GFS IS LIKELY TOO OVERDEVELOPED...MID LEVEL WARM FRONT SHOULD LIFT NORTHWARD ACROSS THE LAKES THURSDAY NIGHT AND THE CHANCE FOR ELEVATED THUNDERSTORMS. THEN WITH WARM AND INCREASED MOIST/UNSTABLE AIRMASS IN ADVANCE OF A COUPLE OF FRONTAL SYSTEMS WILL PROVIDE THE CONTINUED CHANCE FOR CONVECTION THROUGH THE FRIDAY-SATURDAY TIME PERIOD. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY...LHZ422...UNTIL 6 PM SUNDAY. SMALL CRAFT ADVISORY...LHZ421-LHZ441...UNTIL 6 PM SUNDAY. SMALL CRAFT ADVISORY...LHZ442-LHZ443...UNTIL 9 PM SUNDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....BRAVENDER UPDATE.......BRAVENDER MARINE.......DWD SHORT TERM...DWD LONG TERM....BGM YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPRINGFIELD MO 155 PM CDT SUN AUG 20 2006 .DISCUSSION... LATEST RADAR IMAGES SHOW BULK OF RAIN HAS MOVED NORTHEAST OF OUR FORECAST AREA THIS AFTERNOON WITH A RATHER INTENSE STORM JUST EAST OF SHANNON COUNTY. EXTENSIVE CLOUD COVER THUS FAR HAS HELD TEMPERATURES IN THE LOWER TO MID 80S MOST AREAS. RECENT VISIBLE SATELLITE IMAGES SHOW STRATUS EVOLVING INTO SCATTERED TO BROKEN STRATOCUMULUS DECK WITH AFTERNOON MIXING. IN THE SHORT TERM...MAIN FORECAST CHALLENGE CONTINUES TO BE PRECIP CHANCES TONIGHT AND MONDAY. THEREAFTER MAIN FOCUS WILL BE ON TEMPERATURES THROUGH NEXT WEEKEND. WE ARE NOT SEEING ANY STRONG FEATURES UPSTREAM TO GET ANOTHER ROUND OF STORMS GOING AND MOST OF THE LOW LEVEL BOUNDARIES HAVE SHIFTED SOUTH INTO ARKANSAS. LATEST RUC 500 MB HEIGHT FIELD SHOWS A VERY SUBTLE KINK OVER SOUTH SOUTH CENTRAL KANSAS...AND WITH DECENT MOISTURE REMAINING OVER THE AREA...EVEN WITH LIMITED HEATING DUE TO EXTENSIVE CLOUD COVER...WILL LEAVE AT LEAST A SLIGHT CHANCE FOR SHOWERS AND A FEW STORMS THROUGH TONIGHT. THEREAFTER WILL TRIM PRECIP CHANCES TO MAINLY OUR SOUTHERN TIER OF COUNTIES ON MONDAY. THROUGH THE REST OF THE WEEK...OUR AREA WILL CONTINUE TO BE DOMINATED BY UPPER LEVEL RIDGING...BRINGING AROUND ROUND OF DRY AND WARM TO HOT TEMPERATURES. STILL LOOKS LIKE OVERALL TEMPERATURES REMAIN COOLER THAN LAST WEEK AS 850 MB TEMPS REMAIN AT OR BELOW 20 DEG C...HOWEVER EXPECT ABOVE NORMAL TEMPERATURES FROM WED TO FRI. EXTENDED MODELS ARE TRENDING TOWARD MORE UPPER RIDGING AND LESS TROUGHING OVER OUR AREA INTO THE WEEKEND...DECREASING OUR CHANCES OF SEEING FROPA AND RAIN LATE FRIDAY INTO SATURDAY. FOR NOW WILL LEAVE SLIGHT CHANCES IN GRIDS FOR FRIDAY AND SATURDAY AND MONITOR FORECAST TRENDS. TERRY && .AVIATION... IFR CEILINGS ACROSS THE AREA THIS MORNING HAVE GRADUALLY LIFTED INTO THE MVFR CATEGORY THIS AFTERNOON AT KJLN AND KSGF. THERE IS AN OUTSIDE CHANCE OF A SHOWER OR TWO IN THE VICINITIES OF THE TERMINALS THIS AFTERNOON. HOWEVER...THE BETTER CHANCES OF SCATTERED THUNDERSTORMS WILL EXIST FURTHER SOUTH ALONG THE ARKANSAS BORDER WHERE MORE SOLAR INSOLATION HAS OCCURRED TODAY. WILL NEED TO MONITOR THE EVOLUTION OF CEILINGS THIS AFTERNOON INTO THE EVENING HOURS. MOS GUIDANCE KEEPS OVERCAST CONDITIONS OVER THE TERMINALS THROUGH THE NIGHT. HOWEVER...LOOKING AT RH CROSS SECTIONS...THE SATURATED LAYER BECOME QUITE THIN BY 00Z. AS A FIRST GUESS...I WENT AHEAD AND DECIDED TO SCATTER OUT CEILINGS TOWARD EVENING. NEXT CONCERN WILL BE POSSIBLE VISIBILITY RESTRICTIONS OVERNIGHT...AS MOS GUIDANCE IS PICKING UP ON MVFR VISIBILITIES DURING THE PREDAWN HOURS. THE COOL AND MOIST AIRMASS WHICH WAS TO THE NORTH THIS MORNING WILL LIKELY BE OVER THE FORECAST AREA BY TONIGHT. LOOKING AT SUNDAY MORNING OBS TO THE NORTH...A NICE SWATH OF 3 TO 5 VISIBILITIES DID DEVELOP ACROSS NORTHERN AND CENTRAL MISSOURI. WITH THESE FACTORS IN MIND...THE 18Z TAFS WILL HAVE MVFR VISIBILITIES AFTER MIDNIGHT AT BOTH TERMINAL LOCATIONS. SAW && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. $$ WFO SGF mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 314 PM CDT SUN AUG 20 2006 .SHORT TERM... KIND OF A COMPLICATED NEAR TERM FORECAST TODAY...WITH THE MAIN CHALLENGE ONCE AGAIN REGARDING CONVECTION TONIGHT. WILL USE A MODEL BLEND TODAY FOR THE FORECAST. TONIGHT...AT 19Z...SFC MAP SHOWS A TROUGH JUST WEST OF A KMOT TO KBIS LINE. HARDLY ANY CLOUDS AT ALL RIGHT ALONG OR BEHIND THE SFC TROUGH. MODELS HAVE BEEN TRYING TO SAY IT WILL BE A COLD FRONTAL PASSAGE...BUT AM HARD PRESSED TO FIND A COLD FRONT. VISIBLE SATELLITE IMAGERY AND CANADIAN RADARS DO SHOW SOME ENHANCED CONVECTIVE DEVELOPMENT ALONG A LAKE WINNIPEG TO BRANDON (MB) TO ESTEVAN (SK) LINE...WHERE THE LATEST RUC SHOWS THE BEST 925- 850MB COLD ADVECTION. THEREFORE THIS IS LIKELY THE TAIL END OF THE COLD FRONT WITH THE TROUGH EXTENDING SOUTH OF THAT AREA. RUC DOING A DECENT JOB WITH THE SFC FEATURES...AND IT FORECASTS THE TROUGH/FRONT TO A KDVL TO EAST OF KBIS LINE BY 00Z...AND THEN QUICKLY INTO THE EASTERN HALF OF OUR FA AFTER 06Z. THE IS PRETTY QUICK TIMING...WHICH DOES SEEM TO BE THE TREND TODAY. THERE HAS BEEN SOME ELEVATED CONVECTION ALL DAY OVER CENTRAL AND EASTERN ND. AT 850 MB...THE RUC SHOWED A SOMEWHAT WEAK JET (AROUND 30 KTS) WITH WARM ADVECTION AND A THIN RIBBON OF MOISTURE. JUST ENOUGH TO MAINTAIN SOME WEAK CONVECTION. THRU MIDNIGHT...MAIN QUESTION IS WHETHER ANY CONVECTION CAN BECOME SFC BASED. THERE IS A THIN RIBBON OF 60F SFC DEW POINTS THAT EXTEND UP TOWARD KBIS/KJMS. SPC HOURLY MESOANALYSIS SHOWS THE BEST CRAVEN/BROOKS SIGNIFICANT SEVERE PARAMETER SOUTH OF KBIS. THIS COULD BE THE AREA TO WATCH FOR SFC BASED CONVECTION THIS EVENING...AND AN SWOMCD (CONVECTIVE DISCUSSION) HAS BEEN ISSUED FOR THIS AREA. THINK THE ONGOING WEAK ELEVATED CONVECTION WILL CONTINUE AHEAD OF THE TROUGH OVER OUR FA THRU THE EVENING. CONVECTION ALONG THE COLD FRONT IN CANADA SO FAR LOOKS PRETTY WEAK. AFTER MIDNIGHT...WILL ONLY MAINTAIN A SLIGHT CHANCE OF RAIN IN THE FAR SOUTHEAST FA. MON/MON NIGHT...NEXT SFC HIGH BUILDS SOUTH WITH COOL AND DRY WEATHER EXPECTED. TUE/WED...TUE LOOKS CONTINUED QUIET AS RETURN FLOW ONCE AGAIN ESTABLISHES ITSELF. NEXT CHANCE OF RAIN COMES TUE NIGHT INTO WED...AS ANOTHER ROUND OF ELEVATED CONVECTION. HAVE BEEN WATCHING THIS EVENT FOR SEVERAL DAYS NOW...ALL DEPENDS WHERE THE SFC FEATURES SET UP. GFS CONTINUES TO SHOW THE LOW DEVELOPING OVER THE WESTERN DAKOTAS WITH A WARM FRONT EAST OF IT. CONVECTION COULD GET GOING TUE NIGHT NORTH OF THIS BOUNDARY. CHANCES THEREFORE WOULD LOOK A BIT BETTER ACROSS OUR NORTHERN FA. THE SOUTHERN FA COULD BE DEALING WITH CAPPING ISSUES. .LONG TERM (THU-SUN)... LONG RANGE MODELS ARE SIMILAR WITH OVERALL 500MB PATTERN...BUT STILL DO HAVE SOME TIMING DIFFERENCES. ALL THE MODELS MOVE A SHORTWAVE THROUGH THE 500MB FLOW IN CONJUNCTION WITH A SURFACE LOW PRESSURE SYSTEM IN THE THU TO SAT TIME FRAME...BUT DIFFER ON WHEN...SO KEPT WITH FORECAST CONTINUITY OF THU AND FRI...AND KEPT SAT DRY AT THIS TIME. AS FAR AS TEMPS... EXPECT TO REMAIN NEAR NORMAL. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ GODON/NG nd