AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 315 AM MDT FRI SEP 5 2008 .SHORT TERM...WATER VAPOR IMAGERING SHOWING UPPER LEVEL TROF MOVING SE ACROSS SRN WYOMING ATTM. 80KT JET CORE NOSING INTO NW CO WHILE RUC QG VERTICAL VELOCITY FIELDS SHOWING MODEST ASCENT OVER NERN CO WITH THIS DISTURBANCE. CORRESPONDING 88D SHOWING MAIN SWAWTH OF BANDED PRECIP FROM LONGMONT TO NEW RAYMER BUT APPEARS TO BE WEAKENING WITH LACK OF SIGNIFIANT MSTR. THIS SWATH OF LIGHT TO MODERATE PRECIP WILL SAG SOUTHWARD A BIT OVER THE DENVER AREA BEFORE LIFTING EASTWARD DURING THE EARLY MORNING HOURS. THERE ARE STILL SOME SECONDARY AREAS OF SHOWERS ACROSS WY...SO WILL KEEP THE SCATTERED POPS THIS AM. AS THE TROF MOVES EAST...MOST OF THE PRECIP WILL END LATER THIS AM AS SUBSIDENCE MOVES INTO THE REGION AND UPSLOPE FLOW SHIFTS TO MORE SERLY THIS AFTN. THERE IS ANOTHER WEAK DISTURBANCE THAT CLIPS NERN CO LATER TNT WITH SOME WEAK ASCENT. BOTH GFS/NAM SHOWING SOME LIGHT QPF...ESP OVER THE FAR NERN CORNER. WILL ADD SOME LOW POPS FOR LATER TNT. .LONG TERM...THE FORECAST AREA IS UNDER NORTHWESTERLY FLOW ALOFT THROUGH SATURDAY NIGHT...THEN IT BECOMES WESTERLY SUNDAY. AN UPPER TROUGH STAYS TO OUR IMMEDIATE EAST AND NORTHEAST THROUGH MUCH OF THE TIME. A JET MAXIMUM NOSES ACROSS THE NORTHERN FORECAST AREA ON SATURDAY. THE BOUNDARY LAYER FLOW IS PROGGED TO BE UPSLOPE FOR THE PLAINS SATURDAY AFTERNOON INTO EARLY SUNDAY MORNING... EAST-SOUTHEASTERLY SUNDAY AND SUNDAY EVENING. THERE IS SOME LOW LEVEL MOISTURE OVER THE EASTERN FORECAST AREA SATURDAY MORNING. THERE IS ANOTHER BATCH OF LOW LEVEL MOISTURE FOR THE PLAINS LATE SATURDAY NIGHT INTO LATE SUNDAY MORNING. AFTER THAT MOISTURE DOESN`T GET IN HERE UNTIL MONDAY MORNING. THE ALPINE AREAS ARE FAIRLY DRY THROUGH MID DAY SUNDAY...THEN MOISTURE INCREASES A BIT. PRECIPITABLE WATER VALUES RANGE FROM 0.50 TO 0.80 INCH OVER THE PLAINS SATURDAY INTO SUNDAY EVENING. THERE IS A SLIGHT THETA-E AXIS OVER THE SOUTH CENTRAL AND SOUTHEAST FORECAST AREA ON SATURDAY. THERE IS ANOTHER ONE FOR SUNDAY OVER THE FOOTHILLS AND ADJACENT PLAINS. BOUNDARY LAYER DEW POINT VALUES ARE GENERALLY IN THE UPPER 30S TO UPPER 40S FOR THE PLAINS THROUGH ALL THE PERIODS. FOR CAPE ...THERE IS VERY LITTLE OVER THE FORECAST AREA SATURDAY AND SATURDAY NIGHT. BY LATE DAY SUNDAY...THERE IS SOME OVER THE FOOTHILLS AND ADJACENT PLAINS. THE QPF FIELDS SHOW VERY LITTLE MEASURABLE RAINFALL OVER THE FORECAST AREA THROUGH THE PERIODS. THE LAPSE RATE FIELDS SHOW SIGNIFICANT CAPS IN THE LOWER AND MID LEVELS FOR MUCH OF THE FORECAST AREA SATURDAY WELL INTO SUNDAY. THE HIGH COUNTRY AND IMMEDIATE PLAINS HAVE FAIRLY STEEP LAPSE RATES PROGGED FOR SUNDAY LATE IN THE DAY. FOR POPS...WILL LEAVE 0%S GOING SATURDAY INTO SUNDAY. WILL ADJUST SUNDAY AFTERNOON`S POPS TO JUST 10%S IN SOME OF THE MOUNTAINS...FOOTHILLS...AND IMMEDIATE PLAINS ONLY. FOR TEMPERATURES...SATURDAY`S HIGHS ARE 3-7 C WARMER THAN FRIDAY`S. SUNDAY`S COOL OFF A BIT...THE MOST OVER THE NORTHEAST CORNER. FOR THE LATER DAYS...MONDAY THROUGH THURSDAY...MODELS HAVE AN UPPER TROUGH MOVE ACROSS THE FORECAST AREA MONDAY MORNING...THEN ZONAL FLOW INTO WEDNESDAY...BEFORE ANOTHER UPPER TROUGH MOVES ACROSS LATER IN THE DAY INTO THURSDAY. A DECENT SURGE OF UPSLOPE IS PROGGED INTO THE PLAINS AND FOOTHILLS MONDAY MORNING. WILL MAKE FEW ADJUSTMENTS TO THESE LATER DAYS. && .AVIATION...LOCAL AIRPORTS WILL SEE VARYING CIGS THIS AM...AND EXPECT MVFR CIGS IN VCNTY OF SHOWERS. VFR CONDITIONS THIS AFTN AND TNT. NORTHEAST SFC WINDS WILL GRADUALLY SHIFT E-SE THIS AFTN. && .BOU WATCHES/WARNINGS/ADVISORIES...NONE. $$ SWE/RJK co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ALBANY NY 725 PM EDT SAT SEP 6 2008 .SYNOPSIS... TROPICAL STORM HANNA WILL CONTINUE TO ADVANCE NORTHEAST AND EXIT THE REGION OVERNIGHT. IN ITS WAKE...HIGH PRESSURE WILL SETTLE INTO THE REGION THROUGH EARLY NEXT WEEK. THE NEXT CHANCE FOR WET WEATHER ARRIVES TUESDAY WITH A PASSAGE OF A COLD FRONT. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... A DEFINITIVE LINE OF RAIN/NO-RAIN WAS QUITE EVIDENT ON THE RADAR THIS EVENING. MOST OF THE ADIRONDACKS AND WESTERN MOHAWK VALLEY IS MAINLY DRY WHILE OUR SOUTHEAST CWA IS RECEIVING OVER 1 INCH PER HOUR RATES. EXPANDING THE FLOOD WATCH INTO ALL OF SOUTHERN VT AND RENSSELAER COUNTY WHERE RAINFALL RATES ARE INCREASING. REMAINDER OF THE FORECAST UNCHANGED... TROPICAL STORM HANNA CONTINUES TO ACCELERATE NORTHEAST. A DEFORMATION BAND...THAT THE OPERATIONAL GFS AND RUC13 ARE DOING QUITE WELL DEPICTING IN THE 850MB-500MB LAYER...HAS SET UP ACROSS EASTERN PA AND IS EXPECTED TO BE ACROSS SOUTHEAST NY INTO NW CT AND THE BERKS THIS EVENING THEN INTO SOUTHEAST VT TONIGHT AS UPPER JET DEPARTS NORTHEAST CANADA. BASED ON THE LATEST HPC GUIDANCE AND NHC TRACK...WILL KEEP THE FLOOD WATCH IN PLACE AT THIS TIME. HOWEVER...BASED ON UPSTREAM PROJECTIONS...WE WILL NEED TO WATCH FOR THIS DEFORMATION BAND TO IMPACT SCHOHARIE...ALBANY AND RENSSELAER WHERE THE WATCH IS NOT IN EFFECT AT THIS TIME /IT WILL BE CLOSE/. RAINFALL AMOUNTS ARE EXPECTED TO BE AROUND 5 INCHES ACROSS PORTIONS OF THE MID HUDSON VALLEY AND NW CT AND UPSLOPE FAVORED LOCATIONS ACROSS THE BERKS...WITH 2 TO 4 INCHES FROM THE CAPITAL REGION INTO BENNINGTON VT WITH LESS THAN 1 INCH INTO THE DACKS. FRONTAL BOUNDARY APPEARS TO BE QUASI-STATIONARY ACROSS WESTERN/CENTRAL NY WHERE SOME CONVECTION DID ERUPT TODAY...BUT THOUGHTS ARE WITH THE APPROACH OF HANNA THAT SUBSIDENCE WILL INCREASE AND DIMINISH THOSE CONVECTIVE TRENDS. WINDS UPSTREAM ASSOCIATED WITH HANNA ARE STRONGEST ALONG THE COAST WITH NO TROPICAL STORM FORCE WINDS ON THE NORTHWEST PERIPHERY. SO WILL CONTINUE TO KEEP WINDS ACROSS NW CT AND MID HUDSON VALLEY BELOW ADVISORY THRESHOLDS. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY/... IN THE WAKE OF HANNA...INCREASED SUBSIDENCE AND THE PASSAGE OF THE UPSTREAM FRONTAL BOUNDARY WILL COMMENCE AOA 12Z /PROBABLY EARLIER THAN LATER/. A BRISK DAY WITH 15-20KT GUSTS EXPECTED WITH A FRESH NORTHWEST FLOW AS HIGHER PRESSURE RETURNS TO THE REGION. BASED ON UPSTREAM TEMPERATURES INTO THE MID AND UPPER 70S...WILL FOLLOW SUIT FOR MOST AREAS...WITH SOME DOWNSLOPING FOR THE MID HUDSON VALLEY WHERE SOME LOWER 80S ARE EXPECTED UNDER A PTSUNNY SKY. TRANQUIL WEATHER CONTINUES THROUGH MONDAY AS SURFACE HIGH TRACKS SOUTH OF THE CWA. BY LATE IN THE DAY...WARM ADVECTION REGIME UNFOLDS UPSTREAM LATE MONDAY. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... WENT MOSTLY WITH GMOS DATA (WITH SOME MINOR TWEAKING) FOR THIS EXTENDED PACKAGE. THE EXTENDED STARTS OUT WITH HIGH PRESSURE...RETREATING TO OUR EAST MONDAY NIGHT. BOTH THE GFS/EUROPEAN AND HPC INDICATES A PRETTY POTENT SHORT WAVE APPROACHING FROM THE GREAT LAKES MONDAY NIGHT INTO TUESDAY MORNING. THE WARM FRONT IS FORECAST TO IMPACT OUR REGION MONDAY NIGHT...FOLLOWED THE COLD/OCCLUDED FRONT BY LATER ON THE DAY TUESDAY. THIS FRONT LOOKS PRETTY POTENT...AND WILL BE ACCOMPANIED BY THE RR QUAD OF THE 90KT H250 JET. THEREFORE FOUND IT PRUDENT TO INCLUDE THE POSSIBILITY OF THUNDERSTORMS AS H850 TEMPERATURES ARE QUICKLY FORECAST BY BOTH MODELS TO DROP FROM AROUND +15C EARLY TUESDAY TO ONLY +5C BY LATE TUESDAY NIGHT! MUCH COOLER WEATHER LOOKS TO COME IN TUESDAY NIGHT BUT THE AIR MASS WILL MODERATE QUICKLY AS THE FLOW ALOFT BECOME FAST ZONAL. SPRAWLING HIGH PRESSURE TO BUILD IN WEDNESDAY THROUGH THURSDAY...WITH THE NEXT SYSTEM TO APPROACH THURSDAY NIGHT INTO FRIDAY. THIS DISTURBANCE WILL FEATURE ANOTHER SURFACE CYCLONE WITH ASSOCIATED FRONTAL SYSTEMS ALONG WITH THE CHANCE FOR MORE SHOWERS. ANOTHER SOMEWHAT COOL AIR MASS IS FORECAST TO FOLLOW FOR SATURDAY. WITH A CYCLONIC FLOW CONTINUING ALOFT...COOLER AIR MOVING OVER LAKE ONTARIO MIGHT BE ENOUGH TO PRODUCE A LAKE RESPONSE...TRIGGERING CLOUDS AND PERHAPS A FEW SHOWERS...ESPECIALLY ACROSS THE ADIRONDACKS. FOR NOW...JUST WENT 20 POP EVERYWHERE FOR NEXT SATURDAY. && .AVIATION /19Z SATURDAY THROUGH THURSDAY/... THE HEAVIEST RAIN...ASSOCIATED WITH HANNA...IS IMPACTING THE KALB/KPOU REGION. HANNA ITSELF WAS IN SOUTHERN NJ AND TRACKING NORTHEAST AT 30 MPH. WILL CONTINUE THE CB IDEA AT KPOU/KALB AS THERE HAVE BEEN OCCASIONAL CLOUD TO GROUND LIGHTNING STRIKES BUT ANY THUNDERSTORMS ARE VERY ISOLATED. THE RAINS ASSOCIATED WITH THE STORM WILL QUICKLY MOVE AWAY FROM THE TAFS SITES LATER THIS EVENING. THE HEAVIEST RAIN IS ABOUT TO MOVE AWAY FROM KGFL WITH ONLY ADDITIONAL LIGHT RAIN OR SCATTERED SHOWERS FOR AWHILE THIS EVENING. IFR CONDITIONS WILL SLOWLY IMPROVE TO MVFR ONCE THE WIND BECOMES N OR NW AND INCREASES OVERNIGHT TO AROUND 12KTS GUSTING TO AROUND 20KT. GUSTY WINDS AND CLOUDS SHOULD PRECLUDE THE FORMATION OF RADIATIONAL FOG AT ALL SITES TONIGHT. A MUCH BETTER DAY ON TAP FOR SUNDAY AS DRY AIR ERODES THE CLOUDS AND SURFACE VISIBILITIES WILL BE UNRESTRICTED. THE ONLY MITIGATING FACTOR WILL BE A CONTINUED GUSTY NORTHWEST WIND STILL APPROACHING 12KTS AT TIMES...GUSTING TO ABOUT 18KTS. OUTLOOK... SUN NIGHT...VFR EVE...MVFR/IFR OVN DUE TO RADIATIONAL FOG. MON...VFR...NO SIG WX. TUE...VFR-MVFR...CHC SHRAS/TSRA. WED/THU...VFR...NO SIG WX. && .FIRE WEATHER... TROPICAL STORM HANNA WILL PRODUCE 3-6 INCHES OF RAINFALL TO THE SOUTH AND EAST OF ALBANY...1-3 INCHES LOCALLY...AND LESS THAN AN INCH OF RAIN NORTH AND WEST OF ALBANY THROUGH TONIGHT. RAINFALL RATES COULD EXCEED AN INCH PER HOUR THIS EVENING SOUTH AND EAST OF ALBANY...AT LEAST IN A FEW SPOTS. IN THE WAKE OF THE STORM TOMORROW...A GUSTY NORTHWEST BREEZE WILL KICK AND RH VALUES ARE FORECAST TO DROP TO BETWEEN 40-50 PERCENT...EXCEPT HIGHER OVER THE SOUTHERN GREENS (ONLY DROPPING TO AROUND 70 PERCENT THERE). A FULL RECOVERY IS EXPECTED SUNDAY NIGHT WITH RH VALUES APPROACHING 100 PERCENT. DRY WEATHER IS FORECAST SUNDAY THROUGH MONDAY WITH NEXT CHANCE OF SHOWERS MONDAY NIGHT INTO TUESDAY. && .HYDROLOGY... SIGNIFICANT RAINFALL IS EXPECTED OVER MUCH OF THE REGION FROM THE CATSKILLS NORTH AND EAST TO AND INCLUDING SOUTHERN VERMONT...WITH TWO TO SIX INCHES TOTAL SOUTH AND EAST OF ALBANY. THE HEAVIEST RAIN IS EXPECTED ACROSS NORTHWESTERN CONNECTICUT...BUT CANNOT RULE OUT AREAS OF HEAVY RAIN ACROSS SOUTHERN VERMONT OR SOME OF THE HIGHER TERRAIN OF THE CATSKILLS WHERE UPSLOPE WINDS ARE LIKELY TO INCREASE THE AMOUNTS OF RAINFALL. MODELING OBSERVED ALONG WITH FORECAST RAINFALL CURRENTLY SUGGESTS THE HOUSATONIC RIVER WILL RISE ABOVE FLOOD STAGE FROM LAKE LILLINONAH UPSTREAM TO THE MASSACHUSETTS/CONNECTICUT STATE LINE. A NUMBER OF OTHER RIVERS WILL GET CLOSE TO FLOOD STAGE INCLUDING THE HOOSIC RIVER IN MASSACHUSETTS AND NEW YORK...THE BATTEN KILL IN SOUTHERN VERMONT...AND THE HEADWATERS OF THE SCHOHARIE AND ESOPUS CREEKS IN THE CATSKILLS. LAKE LILLINONAH HAS BEEN LOWERED ABOUT SEVEN FEET DURING THE LAST COUPLE OF DAYS IN ANTICIPATION OF THE HEAVY RAIN. THEREFORE THERE IS SOME ROOM TO STORE SOME OF THE EXCESS FLOW...WHICH MAY ENABLE POWER PLANT OPERATORS TO KEEP THE HOUSATONIC BELOW FLOOD DOWNSTREAM FROM STEVENSON DAM. THERE IS CONSIDERABLE STORAGE IN ASHOKAN RESERVOIR AND SOME STORAGE IN SCHOHARIE RESERVOIR DUE TO THE DRY WEATHER THE LAST SEVERAL WEEKS. RUNOFF ABOVE SCHOHARIE RESERVOIR IS EXPECTED TO BRING THE WATER LEVEL ABOVE THE NOTCH BUT NOT HIGH ENOUGH TO GO OVER THE MAIN SPILLWAY. NO WATER IS EXPECTED TO SPILL FROM ASHOKAN RESERVOIR. HOWEVER RUNOFF BELOW ASHOKAN WILL CAUSE THE ESOPUS BELOW THE RESERVOIR TO RISE AROUND 3 FEET. TROPICAL STORMS USUALLY HAVE BANDS OF HEAVY RAIN WITH RAINFALL RATES OF 1 TO 2 INCHES PER HOUR...EVEN WHERE NO THUNDER OCCURS. SMALL STREAM...URBAN AND POOR DRAINAGE FLOODING IS LIKELY IN THESE AREAS OF HEAVY RAIN. SOME FLASH FLOODING IS ALSO HIGHLY POSSIBLE. PERSONS LIVING IN FLOOD PRONE AREAS SHOULD KEEP UP WITH LATEST FORECASTS FOR HANNA AND ASSOCIATED RAINFALL. FOR DETAILS ON THE RIVERS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .EQUIPMENT... TROPICAL Z/R RELATIONSHIP REMAINS IN EFFECT ON THE RADAR...ALTHOUGH WE HAVE NOTICED SOME OVERESTIMATE ON PRECIP ALGORITHM. WE WILL CONTINUE TO MONITOR TRENDS AND MAY MAKE ADJUSTMENTS TO THE RADAR PRECIP ALGORITHMS WITH COLLABORATION FROM ERH AND NERFC. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...FLOOD WATCH THROUGH SUNDAY MORNING FOR CTZ001-013. NY...FLOOD WATCH THROUGH SUNDAY MORNING FOR NYZ053-054-058>061- 063>066. MA...FLOOD WATCH THROUGH SUNDAY MORNING FOR MAZ001-025. VT...FLOOD WATCH THROUGH SUNDAY MORNING FOR VTZ013>015. && $$ AVIATION...RCK FOR THE LATEST UPDATES...PLEASE VISIT OUR WEBPAGE AT WWW.WEATHER.GOV/ALBANY ct AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE INDIANAPOLIS IN 127 PM EDT SAT SEP 6 2008 .AVIATION... DISCUSSION FOR 18Z TAFS. VFR CONDITIONS WILL BE THE RULE FOR THE REST OF THIS AFTERNOON. HIGH PRESSURE AT THE SURFACE WILL PROVIDE MOSTLY CLEAR SKIES WITH JUST A FEW SCATTERED FAIR WEATHER CLOUDS TODAY. THESE SHOULD MELT AWAY AFTER SUNSET. HOWEVER SOME HIGH LEVEL CLOUDINESS WILL RAPIDLY MOVE IN FROM THE WEST AHEAD OF AN APPROACHING UPPER LEVEL LOW PRESSURE. THIS WILL SEND GRADUALLY LOWERING CIGS INTO THE AREA THROUGH THE NIGHT...WITH MOST OF THE CLOUDS AT IND AND LAF. A LONGER PERIOD OF CLEAR SKIES AT BMG AND HUF WILL ALLOW FOR LIGHT MVFR FOG TO FORM. BUT RAPIDLY APPROACHING CLOUDS WILL LIMIT THE FOG. BY 10-14Z SOME RAIN SHOWERS WILL MOVE ACROSS THE AREA. THE HEAVIEST RAIN WILL BE OVER NORTHERN INDIANA AND SO WILL KEEP THE LOWEST VSBY IN LAF WHERE MVFR IS EXPECTED. FARTHER SOUTH WILL JUST MENTION SEVERAL HOURS OF VCSH. WITH SUCH A WEAK SYSTEM...VERY LOW CIGS ARE NOT EXPECTED AND THE CLOUDS SHOULD REMAIN VFR WITH 5-7KFT CIGS EXPECTED AFTER 12Z SUNDAY. && .PREV DISCUSSION... /ISSUED 736 AM EDT SAT SEP 6 2008/ DISCUSSION...FORECAST FOCUS WILL BE ON THE NEXT CHANCE OF PRECIP AND SHORT TERM TEMPS. HIGH PRESSURE WAS OVER WRN IOWA/ERN NEBRASKA THIS MORNING. LOW STRATUS TRAPPED UNDER AN INVERSION WERE HANGING AROUND OVER CENTRAL INDIANA AT 07Z. LARGE SCALE H5 TROF WAS OVER THE NATIONS MID SECTION. TODAY AND TONIGHT...TIME HEIGHT SECTIONS AS WELL AS RUC SOUNDINGS AND SATELLITE TRENDS SHOW THE LOW STRATUS GRADUALLY BREAKING UP AND CLEARING OUT LATER THIS MORNING. NEUTRAL TO SLIGHTLY COOL ADVECTION AT H85 WILL RESULT IN HIGHS IN THE UPPER 70S TODAY AND MID 50S TONIGHT. SUNDAY...H5 TROF KICKS A SHORT WAVE ACROSS THE GREAT LAKES ON SUNDAY. GFS/NAM KEEP ANY ASSOCIATED PRECIP IN WITHIN THE AFOREMENTIONED REGION SO HAVE CONTINUED TO KEEP SUNDAY DRY. TEMPS WILL REMAIN RIGHT AT OR SLIGHTLY BELOW NORMAL. MONDAY...A FRONTAL BOUNDARY WILL LAY ACROSS THE CWA ON MONDAY. A SURFACE WAVE WILL MOVE ALONG THIS FRONT FROM MONDAY AFTERNOON INTO THE EVENING. THERE IS SOME...ALTHOUGH NOT A LOT...OF MOISTURE AVAILABLE WITH THIS SYSTEM. HAVE STARTED WITH CHANCE POPS NORTHERN HALF OF THE CWA ON MONDAY DURING THE DAY THEN SPREAD POPS TO THE ENTIRE CWA BY MONDAY EVENING AS THE SURFACE WAVE IS CLOSEST. TUESDAY AND WEDENSDAY...A 1024 HIGH OVER IA/MO ON TUES WILL QUICKLY PUSH THE AFOREMENTIONED FRONTAL BOUNDARY OUT OF CENTRAL INDIANA. DRY CONDITIONS AND SLIGHTLY BELOW NORMAL TEMPS CAN BE EXPECTED ON TUES AND WED. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ AVIATION...JOHNSON in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE INDIANAPOLIS IN 736 AM EDT SAT SEP 6 2008 .AVIATION DISCUSSION...FOR THE 12Z TAFS VFR CONDITIONS THROUGH THE TAF PERIOD. HIGH PRESSURE WILL BUILD INTO INDIANA DURING THE DAY. MOISTURE FROM HANNA WILL REMAIN WELL EAST OF INDIANA. SOME LINGERING LOW LVL MOISTURE ALONG WITH AFTN INSTABILITY WILL ALLOW FOR SOME CU DEVELOPMENT BUT THESE WILL DISSIPATE ARND SS. SOME MID LVL MOISTURE WILL MOVE THROUGH INDIANA TONIGHT. THIS WILL GIVE A BKN AC CLOUDS. && .DISCUSSION...FORECAST FOCUS WILL BE ON THE NEXT CHANCE OF PRECIP AND SHORT TERM TEMPS. HIGH PRESSURE WAS OVER WRN IOWA/ERN NEBRASKA THIS MORNING. LOW STRATUS TRAPPED UNDER AN INVERSION WERE HANGING AROUND OVER CENTRAL INDIANA AT 07Z. LARGE SCALE H5 TROF WAS OVER THE NATIONS MID SECTION. TODAY AND TONIGHT...TIME HEIGHT SECTIONS AS WELL AS RUC SOUNDINGS AND SATELLITE TRENDS SHOW THE LOW STRATUS GRADUALLY BREAKING UP AND CLEARING OUT LATER THIS MORNING. NEUTRAL TO SLIGHTLY COOL ADVECTION AT H85 WILL RESULT IN HIGHS IN THE UPPER 70S TODAY AND MID 50S TONIGHT. SUNDAY...H5 TROF KICKS A SHORT WAVE ACROSS THE GREAT LAKES ON SUNDAY. GFS/NAM KEEP ANY ASSOCIATED PRECIP IN WITHIN THE AFOREMENTIONED REGION SO HAVE CONTINUED TO KEEP SUNDAY DRY. TEMPS WILL REMAIN RIGHT AT OR SLIGHTLY BELOW NORMAL. MONDAY...A FRONTAL BOUNDARY WILL LAY ACROSS THE CWA ON MONDAY. A SURFACE WAVE WILL MOVE ALONG THIS FRONT FROM MONDAY AFTERNOON INTO THE EVENING. THERE IS SOME...ALTHOUGH NOT A LOT...OF MOISTURE AVAILABLE WITH THIS SYSTEM. HAVE STARTED WITH CHANCE POPS NORTHERN HALF OF THE CWA ON MONDAY DURING THE DAY THEN SPREAD POPS TO THE ENTIRE CWA BY MONDAY EVENING AS THE SURFACE WAVE IS CLOSEST. TUESDAY AND WEDENSDAY...A 1024 HIGH OVER IA/MO ON TUES WILL QUICKLY PUSH THE AFOREMENTIONED FRONTAL BOUNDARY OUT OF CENTRAL INDIANA. DRY CONDITIONS AND SLIGHTLY BELOW NORMAL TEMPS CAN BE EXPECTED ON TUES AND WED. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. $$ PUBLIC...SALLY AVIATION...SH in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE INDIANAPOLIS IN 300 AM EDT SAT SEP 6 2008 .DISCUSSION...FORECAST FOCUS WILL BE ON THE NEXT CHANCE OF PRECIP AND SHORT TERM TEMPS. HIGH PRESSURE WAS OVER WRN IOWA/ERN NEBRASKA THIS MORNING. LOW STRATUS TRAPPED UNDER AN INVERSION WERE HANGING AROUND OVER CENTRAL INDIANA AT 07Z. LARGE SCALE H5 TROF WAS OVER THE NATIONS MID SECTION. TODAY AND TONIGHT...TIME HEIGHT SECTIONS AS WELL AS RUC SOUNDINGS AND SATELLITE TRENDS SHOW THE LOW STRATUS GRADUALLY BREAKING UP AND CLEARING OUT LATER THIS MORNING. NEUTRAL TO SLIGHTLY COOL ADVECTION AT H85 WILL RESULT IN HIGHS IN THE UPPER 70S TODAY AND MID 50S TONIGHT. SUNDAY...H5 TROF KICKS A SHORT WAVE ACROSS THE GREAT LAKES ON SUNDAY. GFS/NAM KEEP ANY ASSOCIATED PRECIP IN WITHIN THE AFOREMENTIONED REGION SO HAVE CONTINUED TO KEEP SUNDAY DRY. TEMPS WILL REMAIN RIGHT AT OR SLIGHTLY BELOW NORMAL. MONDAY...A FRONTAL BOUNDARY WILL LAY ACROSS THE CWA ON MONDAY. A SURFACE WAVE WILL MOVE ALONG THIS FRONT FROM MONDAY AFTERNOON INTO THE EVENING. THERE IS SOME...ALTHOUGH NOT A LOT...OF MOISTURE AVAILABLE WITH THIS SYSTEM. HAVE STARTED WITH CHANCE POPS NORTHERN HALF OF THE CWA ON MONDAY DURING THE DAY THEN SPREAD POPS TO THE ENTIRE CWA BY MONDAY EVENING AS THE SURFACE WAVE IS CLOSEST. TUESDAY AND WEDENSDAY...A 1024 HIGH OVER IA/MO ON TUES WILL QUICKLY PUSH THE AFOREMENTIONED FRONTAL BOUNDARY OUT OF CENTRAL INDIANA. DRY CONDITIONS AND SLIGHTLY BELOW NORMAL TEMPS CAN BE EXPECTED ON TUES AND WED. && .AVIATION DISCUSSION...FOR THE 06Z TAFS 11-3.9 MICRON LOOP WAS SHOWING SOME BREAKS IN THE SC FIELD ALONG A CORRIDOR FM BMG TO IND. IN FACT DEW PT DEPRESSION AT BMG WAS ONLY 2 LATE THIS EVE WHEREAS OTHERSITES STILL SAW A 5 OR 6 DEGREE SPREAD. MODELS WERE ALSO STILL SHOWING LOTS OF LOW LVL MOISTURE OVERNGT ESP S AND E OF A HUF-IND LINE. FINALLY...FOGGY PROGRAM FAVORS ST OVER FOG TGNT AND MOS SEEMS TO BE RESPONDING. SO...WL DELAY AND LESS THAN FOG IMPACT TNGT AND ONLY GO WITH MVFR. HOWEVER...STILL COULD BE SOME IFR AT BMG IF THE CLOUDS DONT FILL BACK IN SOON. MEANWHILE...EXPECT THE SC TO LOWER TO THE IFR CAT AT TIMES AS IT HAS THE PAST COUPLE OF DAYS. MODEL TIME SECS AND CU PROGS FAVOR CLOUDS LIFTING TO VFR BY MID MRNG ESP AT LAF. CU SHOULD ALSO SCATTERED IN THE AFTERNOON. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. $$ PUBLIC...SALLY AVIATION...MK in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TOPEKA KS 709 PM CDT SAT SEP 6 2008 .UPDATE... UPDATED FOR 00 UTC AVIATION... && .AVIATION... SCATTERED SHOWERS WILL CONTINUE TO DECREASE IN COVERAGE AS MAJORITY OF ACTIVITY REMAINS EAST OF THE REGION. MVFR CONDITIONS WILL PERSIST INTO THE OVERNIGHT HOURS WITH IFR CONDITIONS EXPECTED TO BECOME MORE WIDESPREAD AFTER MIDNIGHT. CEILINGS WILL CONTINUE TO LOWER AND PATCHY DENSE FOG WILL DEVELOP AFTER MIDNIGHT..REDUCING VISIBILITIES TO UNDER 3 MILES AT TAF SITES. LOW CLOUDS AND FOG WILL BEGIN TO SLOWLY MIX OUT BY MID MORNING WITH 12 KFT PRESENT THEREAFTER. && .PREV DISCUSSION... /ISSUED 305 PM CDT SAT SEP 6 2008/ DISCUSSION... TWO WAVES MOVING THOUGH THE CENTRAL PLAINS THIS AFTERNOON AS SEEN IN THE WATER VAPOR AND PROFILERS. FIRST WAS LOCATED OVER NEBRASKA AND THE OTHER MOVING INTO SOUTHWEST MISSOURI. ISENTROPIC FORECASTS SHOW SUBSIDENCE BEHIND THE WAVES LATER THIS EVENING. PLENTY OF LOW LEVEL MOISTURE WILL REMAIN ACROSS THE AREA OVERNIGHT AND SUNDAY. INITIAL CONCERNS THAT AREAS OF FOG WILL FORM ACROSS THE AREA ESPECIALLY NORTH OF HIGHWAY 56 TONIGHT. EVEN WITH CLOUDS PRESENT OVERNIGHT WILL APPROACH THE CROSS OVER TEMPERATURE WITH SOME DENSE FOG POSSIBLE. INITIALLY WILL LEAVE A SMALL POP IN FOR TONIGHT WITH SOME SCATTERED LIGHT SHOWERS EARLY THEN LATER TONIGHT WITH WARM AIR ADVECTION WITH THE LOW LEVEL JET INITIATING THUNDERSTORMS NORTH OF THE FRONT ACROSS NORTHERN OKLAHOMA. THIS IS DEPICTED BY RUC/GFS AND NAM TO DEVELOP LATER TONIGHT AND MAINLY WILL AFFECT ONLY THE SOUTHERN COUNTIES OF THE CWA. HAVE MAINTAINED THE HIGHEST CHANCES ACROSS EAST CENTRAL KANSAS TONIGHT AND SUNDAY MORNING. AS THE LOW LEVEL JET WEAKENS BY THE AFTERNOON EXPECT PRECIPITATION TO DECREASE DRAMATICALLY. MADE ONLY SLIGHT ADJUSTMENT TO THE LOWS TONIGHT AND ON SUNDAY LOWERED HIGHS DUE TO CLOUDS AND LITTLE MIXING. 53 SUNDAY NIGHT...UPPER TROUGH DIGS INTO MONTANA. QUESTIONS ARISE REGARDING THE NORTHWARD PROGRESS OF THE FRONT AS SOUTHERLY FLOW INCREASES OVERNIGHT...AND THE TIMING OF A SERIES OF WAVES ALSO LIFTING THROUGH THE STATE DURING THE OVERNIGHT HOURS. GFS/ECMWF/NAM ALL SEEM TO BE DRIVING THE FRONT FURTHER NORTH THAN PREVIOUSLY ADVERTISED...UP INTO NE BY MONDAY MORNING. MADE SEVERAL CHANGES TO GOING GRIDS SHIFTING THE AXIS FOR BEST PRECIP FURTHER NORTH. MONDAY...BEST INSTABILITY AXIS SETS UP RIGHT OVER TOP OF THE CWA AHEAD OF THE COLD FRONT THAT WILL PUSH THROUGH MONDAY AFTERNOON AND EVENING. DECENT DEEP LAYER SHEAR NEAR THIS INSTABILITY AXIS MAY ALLOW FOR SOME STRONG STORMS TO DEVELOP MONDAY AFTERNOON...WITH LARGE HAIL LOOKING TO BE THE PRIMARY THREAT. FRONT WILL EXIT SOUTHEAST LATE MON NIGHT. SUBSIDENCE AND COOLER TEMPS ON TRACK FOR TUESDAY. LOWERED LOWS MON NITE/TUES MORN TO THE MID 40S NORTH CENTRAL TO THE LOWER 50S EAST CENTRAL. LATE TUES/EARLY WED AND THEREAFTER...WARM FRONT LIFTS BACK NORTHWARD...AND LOW LEVEL JET INTENSIFIES OVERNIGHT AHEAD OF NEXT TROUGH. MODELS COINCIDENTLY DEPICT A PIECE OF ENERGY EJECTING NORTHEASTWARD WED MORN AND ISENTROPIC ASCENT THROUGH MUCH OF THE DAY WED WHICH WILL AID IN THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS ACROSS THE NORTH CENTRAL/NORTHEAST PART OF THE STATE. WITH GOOD UPPER DIVERGENCE IN RIGHT ENTRACE REGION OF UPPER JET STREAK...PASSAGE OF 500MB TROUGH...AND SFC COLD FRONT SWINGING ON THROUGH THURSDAY LATE THURS MORNING AND AFTERNOON...TAPERED BEST POPS IN THIS TIME FRAME. OTHERWISE...TWEAKED PRECIP ONSET A BIT SOONER WITH INITIAL WAVE PASSAGE LATE TUES...AND CLEARED OUT LOCAL AREA A BIT MORE QUICKLY ON THE FLIP SIDE THURSDAY EVENING WITH PROGRESSIVE NATURE OF THE FRONT. MODELS REMAIN IN RELATIVELY GOOD AGREEMENT WITH THIS SOLUTION...SO FORECAST CONFIDENCE IS ABOVE AVERAGE. SUNNY AND DRIER CONDITIONS TO SETTLE IN FRIDAY AND SATURDAY AS A SURFACE HIGH BUILDS OVER THE PLAINS...AND A WEAK RIDGE SETS UP ALOFT. TEMPERATURE CHANGES MADE DURING THE PERIOD INCLUDE LOWERING LOWS FRI MORN AS SKIES CLEAR FROM NW TO SE DURING THE NIGHT...RESULTING IN GOOD RADIATIONAL COOLING...AND WEAK CAA BEHIND THE FRONT. PRECIP MIDWEEK MAY KEEP TEMPERATURES EVEN COOLER THAN CURRENTLY DEPICTED...WHICH WILL HAVE TO BE WATCHED OVER THE NEXT FEW DAYS. OTHERWISE...ALL EYES WILL BE ON THE TRACK OF HURRICANE IKE AS IT CHURNS OVER THE GULF. LUNDE && .TOP WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TOPEKA KS 305 PM CDT SAT SEP 6 2008 .DISCUSSION... TWO WAVES MOVING THOUGH THE CENTRAL PLAINS THIS AFTERNOON AS SEEN IN THE WATER VAPOR AND PROFILERS. FIRST WAS LOCATED OVER NEBRASKA AND THE OTHER MOVING INTO SOUTHWEST MISSOURI. ISENTROPIC FORECASTS SHOW SUBSIDENCE BEHIND THE WAVES LATER THIS EVENING. PLENTY OF LOW LEVEL MOISTURE WILL REMAIN ACROSS THE AREA OVERNIGHT AND SUNDAY. INITIAL CONCERNS THAT AREAS OF FOG WILL FORM ACROSS THE AREA ESPECIALLY NORTH OF HIGHWAY 56 TONIGHT. EVEN WITH CLOUDS PRESENT OVERNIGHT WILL APPROACH THE CROSS OVER TEMPERATURE WITH SOME DENSE FOG POSSIBLE. INITIALLY WILL LEAVE A SMALL POP IN FOR TONIGHT WITH SOME SCATTERED LIGHT SHOWERS EARLY THEN LATER TONIGHT WITH WARM AIR ADVECTION WITH THE LOW LEVEL JET INITIATING THUNDERSTORMS NORTH OF THE FRONT ACROSS NORTHERN OKLAHOMA. THIS IS DEPICTED BY RUC/GFS AND NAM TO DEVELOP LATER TONIGHT AND MAINLY WILL AFFECT ONLY THE SOUTHERN COUNTIES OF THE CWA. HAVE MAINTAINED THE HIGHEST CHANCES ACROSS EAST CENTRAL KANSAS TONIGHT AND SUNDAY MORNING. AS THE LOW LEVEL JET WEAKENS BY THE AFTERNOON EXPECT PRECIPITATION TO DECREASE DRAMATICALLY. MADE ONLY SLIGHT ADJUSTMENT TO THE LOWS TONIGHT AND ON SUNDAY LOWERED HIGHS DUE TO CLOUDS AND LITTLE MIXING. 53 SUNDAY NIGHT...UPPER TROUGH DIGS INTO MONTANA. QUESTIONS ARISE REGARDING THE NORTHWARD PROGRESS OF THE FRONT AS SOUTHERLY FLOW INCREASES OVERNIGHT...AND THE TIMING OF A SERIES OF WAVES ALSO LIFTING THROUGH THE STATE DURING THE OVERNIGHT HOURS. GFS/ECMWF/NAM ALL SEEM TO BE DRIVING THE FRONT FURTHER NORTH THAN PREVIOUSLY ADVERTISED...UP INTO NE BY MONDAY MORNING. MADE SEVERAL CHANGES TO GOING GRIDS SHIFTING THE AXIS FOR BEST PRECIP FURTHER NORTH. MONDAY...BEST INSTABILITY AXIS SETS UP RIGHT OVER TOP OF THE CWA AHEAD OF THE COLD FRONT THAT WILL PUSH THROUGH MONDAY AFTERNOON AND EVENING. DECENT DEEP LAYER SHEAR NEAR THIS INSTABILITY AXIS MAY ALLOW FOR SOME STRONG STORMS TO DEVELOP MONDAY AFTERNOON...WITH LARGE HAIL LOOKING TO BE THE PRIMARY THREAT. FRONT WILL EXIT SOUTHEAST LATE MON NIGHT. SUBSIDENCE AND COOLER TEMPS ON TRACK FOR TUESDAY. LOWERED LOWS MON NITE/TUES MORN TO THE MID 40S NORTH CENTRAL TO THE LOWER 50S EAST CENTRAL. LATE TUES/EARLY WED AND THEREAFTER...WARM FRONT LIFTS BACK NORTHWARD...AND LOW LEVEL JET INTENSIFIES OVERNIGHT AHEAD OF NEXT TROUGH. MODELS COINCIDENTLY DEPICT A PIECE OF ENERGY EJECTING NORTHEASTWARD WED MORN AND ISENTROPIC ASCENT THROUGH MUCH OF THE DAY WED WHICH WILL AID IN THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS ACROSS THE NORTH CENTRAL/NORTHEAST PART OF THE STATE. WITH GOOD UPPER DIVERGENCE IN RIGHT ENTRACE REGION OF UPPER JET STREAK...PASSAGE OF 500MB TROUGH...AND SFC COLD FRONT SWINGING ON THROUGH THURSDAY LATE THURS MORNING AND AFTERNOON...TAPERED BEST POPS IN THIS TIME FRAME. OTHERWISE...TWEAKED PRECIP ONSET A BIT SOONER WITH INITIAL WAVE PASSAGE LATE TUES...AND CLEARED OUT LOCAL AREA A BIT MORE QUICKLY ON THE FLIP SIDE THURSDAY EVENING WITH PROGRESSIVE NATURE OF THE FRONT. MODELS REMAIN IN RELATIVELY GOOD AGREEMENT WITH THIS SOLUTION...SO FORECAST CONFIDENCE IS ABOVE AVERAGE. SUNNY AND DRIER CONDITIONS TO SETTLE IN FRIDAY AND SATURDAY AS A SURFACE HIGH BUILDS OVER THE PLAINS...AND A WEAK RIDGE SETS UP ALOFT. TEMPERATURE CHANGES MADE DURING THE PERIOD INCLUDE LOWERING LOWS FRI MORN AS SKIES CLEAR FROM NW TO SE DURING THE NIGHT...RESULTING IN GOOD RADIATIONAL COOLING...AND WEAK CAA BEHIND THE FRONT. PRECIP MIDWEEK MAY KEEP TEMPERATURES EVEN COOLER THAN CURRENTLY DEPICTED...WHICH WILL HAVE TO BE WATCHED OVER THE NEXT FEW DAYS. OTHERWISE...ALL EYES WILL BE ON THE TRACK OF HURRICANE IKE AS IT CHURNS OVER THE GULF. LUNDE && .AVIATION... FOR THE 18Z TAFS...PREVAILING MVFR CIGS WILL CONTINUE INTO THE EVENING HOURS. TIME OF ARRIVAL TOOL WOULD BRING THE BACK EDGE OF THE PRECIPITATION INTO THE KTOP AND KFOE TAF SITES AROUND 21Z TO 22Z. LIFT WITH THE UPPER SYSTEMS AS WELL AS ISENTROPIC LIFT WILL MOVE EAST BY 00Z. MODELS DIFFER WITH LOW CIGS THROUGH THE NIGHT WITH THE NAM KEEPING LOW CLOUDS IN WITH THE GFS HAVING VFR CIGS. OPTED TO GO MIDDLE OF THE ROAD AND KEPT MVFR CIGS THROUGH 05Z SUNDAY THEN VFR THEREAFTER. COULD ALSO SEE MVFR VSBYS IN THE 10-14Z PERIOD. 53 && .TOP WATCHES/WARNINGS/ADVISORIES...NONE. && $$ 53/LUNDE ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TOPEKA KS 641 AM CDT SAT SEP 6 2008 .UPDATE... UPDATED FOR 12Z AVIATION. && .DISCUSSION... SEE PREVIOUS DISCUSSION. && .AVIATION... KEPT MVFR VISBY EARLY IN THE PERIOD AS T/TD SPREADS ARE LOW AND WINDS REMAIN LIGHT. RUC/NAM/GFS INDICATE ISENTROPIC SHOWERS WILL SPREAD INTO THE CWA THROUGH THE MORNING HOURS AND BRING PREVAILING MVFR SHRA INTO TAF SITES BY 14/15Z. EXPECT TO CONTINUE THROUGH THE DAY THEN END TOWARD 0Z...WITH THUNDER NOT ANTICIPATED ATTM. 67 && .PREV DISCUSSION... /ISSUED 352 AM CDT SAT SEP 6 2008/ DISCUSSION... 00Z UPPER AIR ANALYSIS INDICATED LARGE SCALE PATTERN DEFINED BY BROAD UPPER LVL TROUGH OVER THE CENTRAL CONUS AND EMBEDDED SHORTWAVE TROUGHS IN NORTHWEST FLOW MOVING INTO THE TROUGH AXIS OVER THE NORTHERN ROCKIES AND INTO THE HIGH PLAINS. AT FORECAST TIME WIDESPREAD CONVECTION WAS ONGOING OVER MUCH OF SOUTH CENTRAL AND CENTRAL KS...SEEMINGLY FORCED BY LOW LVL ISENTROPIC LIFT ENHANCED BY LOW LVL JET THROUGH TX AND OK TAPPING INTO DEEP MOIST AXIS INDICATED OVER TX AND OK PANHANDLES ON H850 00Z ANALYSIS. CLEAR SKIES OVER NORTHEASTERN KS AND EASTERN NE HAVE ALLOWED TEMPERATURES TO COOL TO NEAR OR BELOW 50 DEGREES. TODAY...GFS/NAM INDICATE 305K ISENTROPIC LIFT MOVING NORTH DURING THE MORNING HOURS FROM SOUTHERN KS INTO NORTHEAST AND EAST CENTRAL KS. RAIN SHOWER ACTIVITY IS LIKELY TO CONTINUE AS ISENTROPIC LIFT AXIS SHIFTS NORTH...HOWEVER DEEPER INTO THE COLDER AIR OVER THE TOPEKA CWA INSTABILITY IS NOT AS GREAT AS SOUTHERN KS...SO ONLY MENTIONED ISOLATED TSTMS DURING THE MORNING HOURS FOR SOUTHERN PORTIONS OF THE FORECAST AREA. A SHORTWAVE TROUGH PUSHING INTO WESTERN NE AT FORECAST TIME WILL PROVIDE SOME LARGE SCALE ASCENT FOR CONTINUED PRECIPITATION DEVELOPMENT THIS AFTERNOON AS IT TRANSLATES EAST THROUGH BROAD TROUGH AXIS. AS THE SHORTWAVE TROUGH APPROACHES...LOW LVL FLOW WILL VEER REDUCING LOW TO MID LVL ISENTROPIC LIFT WHICH MAY DISRUPT WIDESPREAD RAIN SHOWER ACTIVITY ACROSS THE CWA THIS AFTERNOON. WHILE SOME MODEST ASCENT WILL ACCOMPANY THE PASSAGE OF THE SHORTWAVE TROUGH...THE COOLEST CORE OF THE TROUGH WILL REMAIN NORTH ACROSS NE...SO BEST ASCENT AND INSTABILITY WILL REMAIN NORTH OF THE CWA THIS AFTERNOON. WITH MOISTURE IN PLACE DUE TO ISENTROPIC LIFT THIS MORNING WILL LIKELY SEE RAIN SHOWERS REDEVELOP OVER THE NORTHERN AND EASTERN PORTIONS OF THE CWA. NORTH CENTRAL KS IS A TOUGHER CALL SUBSIDENCE ON THE BACKSIDE OF THE TROUGH MAY SUPPRESS RAIN SHOWERS AFTER 18Z. DIFFICULT TO COMPLETELY REMOVE POPS ATTM...BUT HAVE ONLY LOW CHC POPS MENTIONED HERE WITH AROUND 50 PERCENT POPS IN THE FORECAST FOR NORTHEAST AND EAST CENTRAL KS. WITH A COOLER START TO THE DAY...AND WIDESPREAD CLOUD COVER/PRECIPITATION HAVE HIGHS IN THE MID TO UPPER 60S ACROSS THE CWA. TONIGHT...BEHIND THE SHORTWAVE TROUGH ISENTROPIC DOWNGLIDE LOOKS TO PUSH THROUGH CENTRAL NE AND INTO NORTH CENTRAL KS. TO THE EAST NOCTURNAL ENHANCEMENT OF LOW LVL JET WILL LIKELY ONCE AGAIN SET UP A BAND OF CONVECTION TO THE EAST OF THE WEAK FRONTAL BOUNDARY SINKING SOUTH THROUGH NORTH CENTRAL KS. DEPENDING ON THE SPEED OF THIS WEAK BOUNDARY AND ASSOCIATED LOW LVL SUBSIDENCE PORTIONS OF EAST CENTRAL KS MAY SEE SOME TSTM ACTIVITY OVERNIGHT ONCE THE LOW LVL JET INTENSIFIES. GFS WAS INDICATING A QPF BULLSEYE OVER SOUTHEAST AND EAST CENTRAL KS TONIGHT BASED ON THIS SCENARIO. IF THIS WEAK FRONTAL BOUNDARY IS QUICKER TO MOVE THROUGH CENTRAL KS...CONVECTION WOULD LIKELY REMAIN WELL SOUTH OF THE CWA. AT THIS TIME IT LOOKS LIKE AREAS ALONG AND SOUTH OF INTERSTATE 35 MAY REMAIN EAST OF THE BOUNDARY AND ALLOW SOME OF THIS NOCTURNAL CONVECTION TO MOVE INTO THE AREA. LOWS TONIGHT WILL NOT BE AS COOL WITH AT LEAST SOME MID TO UPPER LVL CLOUD COVER EXPECTED OVER THE CWA. SUNDAY...A STRONG SHORTWAVE TROUGH LOOKS TO PUSH OVER THE NORTHERN ROCKIES LATE SUNDAY AFTERNOON INTO THE OVERNIGHT HOURS. THE RESPONSE TO THE APPROACHING TROUGH WOULD BE FOR LOW LVL ISENTROPIC LIFT TO ONCE AGAIN MOVE NORTH TOWARDS THE TOPEKA CWA. AT THIS TIME THE TIMING OF THIS STRONGER SHORTWAVE TROUGH WOULD SEEM TO DELAY THE ONSET OF PRECIPITATION TO AFTER SUNSET ON SUNDAY. THE GFS IS QUICKER THAN THE NAM IN BRINGING ISENTROPIC LIFT ON THE 305K SFC BACK OVER THE CWA SUNDAY AFTERNOON. DUE TO TIMING DIFFERENCES KEPT SLIGHT CHANCE POPS IN THE FORECAST FOR SUNDAY. THE BEST CHANCE FOR PRECIPITATION LOOKS TO BE SUNDAY NIGHT AS LLJ RAMPS UP ONCE AGAIN AND IMPINGES ON THE STEEPER 305K ISENTROPIC SFC OVER THE CWA. UPPED POPS FOR THE FORECAST AREA SUNDAY NIGHT AS A RESULT. MONDAY...THE STRONG SHORTWAVE TROUGH WILL CONTINUE EAST THROUGH NORTHERN KS AND SOUTHERN NE. INCREASED POPS A BIT DURING THE DAY ON MONDAY WITH 00Z H250 ANALYSIS INDICATING 115 KT JET STREAK EMBEDDED WITHIN THIS WAVE OVER WESTERN CANADA ATTM. A COLD FRONT WILL FOLLOW CLOSELY BEHIND THIS STRONG TROUGH...AND PRECIPITATION CHANCES WILL DIMINISH BEHIND THIS BOUNDARY MONDAY NIGHT AS BROAD SUBSIDENCE WORKS SOUTHEAST INTO THE CWA. MONDAY NIGHT COULD BE FAIRLY COOL BEHIND THE COLD FRONT...WITH TEMPERATURES DIPPING INTO THE UPPER 40S FOR PORTIONS OF NORTH CENTRAL AND NORTHEAST KS. TUESDAY...AT THIS TIME LARGE SCALE SUBSIDENCE LOOKS TO DOMINATE THE WX PATTERN OVER THE CWA...SO A DRY FORECAST AND CLEARING SKIES SHOULD BE ON ORDER. EXTENDED...NO CHANGES MADE AT THIS TIME. CAVANAUGH && .TOP WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TOPEKA KS 1250 PM CDT FRI SEP 5 2008 .UPDATE... UPDATE FOR 18 UTC AVIATION. && .DISCUSSION... SEE PREVIOUS DISCUSSION. && .AVIATION... DRY MID LEVELS PER 12Z TOP SOUNDING MAKING PRECIPITATION DIFFICULT TO REACH THE GROUND. MAY SEE CEILINGS AND VISIBILITIES BRIEFLY DROP TO MVFR RANGE...BUT SEE LITTLE JUSTIFICATION FOR INCLUSION GIVEN PRECIPITATION COVERAGE. SHOULD SEE A BREAK IN SIGNIFICANT WEATHER THIS EVENING...BUT LIGHT WINDS AND RESIDUAL LOW LEVEL MOISTURE MAY ALLOW FOR BR DEVELOPMENT AROUND OVERNIGHT INTO EARLY SATURDAY. NEXT PRECIPITATION CHANCES COME IN BY LATE SATURDAY MORNING. && .PREV DISCUSSION... /ISSUED 359 AM CDT FRI SEP 5 2008/ DISCUSSION... FIRST IN A LONG SERIES OF WAVES IN THE PERSISTENT LONG WAVE TROF IS AFFECTING WESTERN KANSAS EARLY THIS MORNING. RADAR DATA INDICATED SHOWERS AND THUNDERSTORMS MOVING EASTWARD JUST AHEAD OF 700 MB TROF AXIS. RUC LOOKS PRETTY GOOD IN THE NEAR TERM...ALTHOUGH PRECIPITATION IS FALLING FURTHER EAST THAN THE PRECIPITATION DEPICTION FROM RUC. WARM ADVECTION MAY BE A BIT STRONGER THAN FORECAST BUT NOT TOO CONCERNED WITH RAPID ADVANCEMENT EAST OF THIS RAIN AS LAST EVENINGS SOUNDINGS WERE VERY DRY JUST OFF THE SURFACE. APPROACHING PRECIPITATION WILL TAKE AWHILE TO SATURATE AIRMASS. STILL...EXPECT PRECIP TO MAKE IT TO THE ENTIRE FORECAST AREA BY EARLY AFTERNOON. THE NEXT FEW DAYS ARE MESSY TO SAY THE LEAST. SEVERAL SHORTWAVES DEPICTED IN GFS/NAM/ECMWF. WITH PERSISTENT TROF ALOFT...EACH WEAK WAVE HAS ENOUGH UPPER DIVERGENCE TO INCREASE LOW LEVEL WARM ADVECTION AND ASSOCIATED ISENTROPIC LIFT. THE MAIN DIFFICULTY IS TIMING THIS PRECIPITATION POTENTIAL...AND HARDER EVEN IS TIMING THE DRY PERIODS. PREVIOUS FORECAST HAD LOW POP SOLUTION FOR ALL PERIODS THOUGH THE NEXT SEVERAL DAYS...AND HARD AS I TRY I AM UNABLE TO REDUCE TEMPORAL COVERAGE OF THESE POPS. THUS...PRETTY MUCH LEFT PREVIOUS FORECAST ALONE PAST SATURDAY. WILL DEFINITELY NEED WATCHING AS INDIVIDUAL WAVES ARE RESOLVED AND TIMING IS BETTER FORECAST. && .TOP WATCHES/WARNINGS/ADVISORIES...NONE. && $$ HARDING/65 ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TOPEKA KS 714 AM CDT FRI SEP 5 2008 .UPDATE... FORECAST AND AVIATION UPDATE. && .DISCUSSION... DID A QUICK UPDATE TO POPS/WX...TO EXTEND EASTERN EDGE OF POPS THIS MORNING AND INCREASE COVERAGE A BIT TO BLEND WITH NEIGHBORS THIS AFTERNOON. NOT EXPECTING MUCH BESIDES SHOWERS LACKING INSTABILITY IN THE SOUNDINGS. MAY TAKE A BIT FOR COLUMN TO SATURATE CONSIDERING DRY AIR AT THE SURFACE. && .AVIATION... MONITORING VISBYS AT TOP AND FOE ATTM. EXPECT 1/2SM VISBYS TO BREAK UP BY 14Z AS SUN COMES UP. WINDS LIGHT AND VARIABLE THIS MORNING UNTIL WEAK FRONTAL BOUNDARY PUSHES THROUGH IN THE AFTERNOON AND BRINGS A NORTHERLY COMPONENT TO THE WINDS. HAVE VCSH IN TAF SITES WAITING TO SEE IF DRY AIR EVAPS SHOWERS BEFORE THEY HIT THE GROUND. WILL PROBABLY NEED A PREVAILING -SHRA GROUP AT SOME POINT THIS AFTERNOON. 67 && .PREV DISCUSSION... /ISSUED 359 AM CDT FRI SEP 5 2008/ DISCUSSION... FIRST IN A LONG SERIES OF WAVES IN THE PERSISTENT LONG WAVE TROF IS AFFECTING WESTERN KANSAS EARLY THIS MORNING. RADAR DATA INDICATED SHOWERS AND THUNDERSTORMS MOVING EASTWARD JUST AHEAD OF 700 MB TROF AXIS. RUC LOOKS PRETTY GOOD IN THE NEAR TERM...ALTHOUGH PRECIPITATION IS FALLING FURTHER EAST THAN THE PRECIPITATION DEPICTION FROM RUC. WARM ADVECTION MAY BE A BIT STRONGER THAN FORECAST BUT NOT TOO CONCERNED WITH RAPID ADVANCEMENT EAST OF THIS RAIN AS LAST EVENINGS SOUNDINGS WERE VERY DRY JUST OFF THE SURFACE. APPROACHING PRECIPITATION WILL TAKE AWHILE TO SATURATE AIRMASS. STILL...EXPECT PRECIP TO MAKE IT TO THE ENTIRE FORECAST AREA BY EARLY AFTERNOON. THE NEXT FEW DAYS ARE MESSY TO SAY THE LEAST. SEVERAL SHORTWAVES DEPICTED IN GFS/NAM/ECMWF. WITH PERSISTENT TROF ALOFT...EACH WEAK WAVE HAS ENOUGH UPPER DIVERGENCE TO INCREASE LOW LEVEL WARM ADVECTION AND ASSOCIATED ISENTROPIC LIFT. THE MAIN DIFFICULTY IS TIMING THIS PRECIPITATION POTENTIAL...AND HARDER EVEN IS TIMING THE DRY PERIODS. PREVIOUS FORECAST HAD LOW POP SOLUTION FOR ALL PERIODS THOUGH THE NEXT SEVERAL DAYS...AND HARD AS I TRY I AM UNABLE TO REDUCE TEMPORAL COVERAGE OF THESE POPS. THUS...PRETTY MUCH LEFT PREVIOUS FORECAST ALONE PAST SATURDAY. WILL DEFINITELY NEED WATCHING AS INDIVIDUAL WAVES ARE RESOLVED AND TIMING IS BETTER FORECAST. && .TOP WATCHES/WARNINGS/ADVISORIES...DENSE FOG ADVISORY UNTIL 10 AM FRIDAY FOR KSZ026-KSZ039-KSZ040-KSZ054-KSZ055-KSZ056-KSZ058-KSZ059. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TOPEKA KS 359 AM CDT FRI SEP 5 2008 .DISCUSSION... FIRST IN A LONG SERIES OF WAVES IN THE PERSISTENT LONG WAVE TROF IS AFFECTING WESTERN KANSAS EARLY THIS MORNING. RADAR DATA INDICATED SHOWERS AND THUNDERSTORMS MOVING EASTWARD JUST AHEAD OF 700 MB TROF AXIS. RUC LOOKS PRETTY GOOD IN THE NEAR TERM...ALTHOUGH PRECIPITATION IS FALLING FURTHER EAST THAN THE PRECIPITATION DEPICTION FROM RUC. WARM ADVECTION MAY BE A BIT STRONGER THAN FORECAST BUT NOT TOO CONCERNED WITH RAPID ADVANCEMENT EAST OF THIS RAIN AS LAST EVENINGS SOUNDINGS WERE VERY DRY JUST OFF THE SURFACE. APPROACHING PRECIPITATION WILL TAKE AWHILE TO SATURATE AIRMASS. STILL...EXPECT PRECIP TO MAKE IT TO THE ENTIRE FORECAST AREA BY EARLY AFTERNOON. THE NEXT FEW DAYS ARE MESSY TO SAY THE LEAST. SEVERAL SHORTWAVES DEPICTED IN GFS/NAM/ECMWF. WITH PERSISTENT TROF ALOFT...EACH WEAK WAVE HAS ENOUGH UPPER DIVERGENCE TO INCREASE LOW LEVEL WARM ADVECTION AND ASSOCIATED ISENTROPIC LIFT. THE MAIN DIFFICULTY IS TIMING THIS PRECIPITATION POTENTIAL...AND HARDER EVEN IS TIMING THE DRY PERIODS. PREVIOUS FORECAST HAD LOW POP SOLUTION FOR ALL PERIODS THOUGH THE NEXT SEVERAL DAYS...AND HARD AS I TRY I AM UNABLE TO REDUCE TEMPORAL COVERAGE OF THESE POPS. THUS...PRETTY MUCH LEFT PREVIOUS FORECAST ALONE PAST SATURDAY. WILL DEFINITELY NEED WATCHING AS INDIVIDUAL WAVES ARE RESOLVED AND TIMING IS BETTER FORECAST. && .AVIATION... WITH CLEAR SKIES IN THE WAKE OF THE AFTERNOON STRATUS AND MOIST GROUND IN THE KFOE/KTOP...SHOULD CONTINUE TO SEE FOG DEVELOPING IN THESE SITES THROUGH 12Z. DRY AIR JUST OFF THE SFC SUPPORTS SHALLOW FOG AND THIS IN CONJUNCTION WITH SOME AC AND CIRRUS ARRIVING TOWARDS SUNRISE SHOULD SUPPORT A QUICK DISSIPATION TO THE FOG. DRIER GROUND...LOWER DEWPOINTS AND QUICKER ARRIVAL TO THE CLOUDS IN KMHK WAS THE REASON FOR KEEPING FOG OUT OF THE 06Z TAF...BUT WILL NEED TO BE MONITORED FOR ANY CHANGING TRENDS. WILL GO WITH IFR/LIFR VSBYS AT KFOE/KTOP...THEN IMPROVE TO VFR BETWEEN 13 AND 14Z WITH INCREASING AC CLOUDS AS NEXT WAVE APPROACHES WITH A FEW AFTERNOON SHOWERS IN THE KMHK AREA...BUT WITH VFR CIGS6-10KFT. AFTER THE WAVE PASSES BY 00Z...EXPECT LINGERING AC SCT-BKN100 AFTER 00Z. WINDS WILL REMAIN LIGHT THROUGH 06Z/SAT. && .TOP WATCHES/WARNINGS/ADVISORIES...NONE. && $$ HARDING ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 644 AM EDT FRI SEP 5 2008 .SYNOPSIS... HIGH PRESSURE WILL START TO MOVE OUT OF THE REGION THIS MORNING. HANNA IS EXPECTED TO APPROACH THE SOUTHEAST COAST...MAKING LANDFALL ON THE SOUTHEAST COAST EARLY SATURDAY MORNING....BEFORE ACCELERATING NORTHEASTWARD TO ATLANTIC CANADA BY LATE SUNDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LOOK FOR AREAS OF PATCHY FOG THIS MORNING OVER THE CWA. MOST OF IT IS FAIRLY SHALLOW AND SHOULD BURN OFF QUICKLY AFTER SUNRISE. GFS/RUC IN DECENT AGREEMENT WITH RESPECT TO ENHANCED IR IMAGERY OF BANDING DVLMNT ON THE OUTER FRINGES OF HANNA. DECENT FORCING WITH HIGHER MOISTURE FLUX VALUES DVLPS AS OUTER BAND OF HANNA TO THE MOVES CLOSER TO THE CWA FROM THE SSE THIS MORNING. HIGHS TODAY MAINLY IN THE MID TO UPR 80S...WITH LOWER 80S NEAR/ALONG THE IMMEDIATE COASTLINE. FIRST OF MANY OUTER BANDS OF SHRAS/ISOL TSRA WILL LIKELY MOVE THROUGH THE CWA THIS AFTN AND EVE WITH DRY SLOTS (PERIODS OF NO RAIN) DVLPG BEHIND INITIAL BANDS LATE EVE/ERLY OVRNT. LOOK FOR AN AVG OF A TENTH TO A QUARTER OF AN INCH WITH ITS PASSAGE...BUT SOME AREAS COULD SEE HIGHER AMOUNTS POSSIBLY NEARING AN INCH. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/... GFS SHOWING A GOOD DEAL OF MOISTURE FLUX DIV DVLPG BTWN 03Z-14Z OVER SWRN 2/RDS OF THE CWA (S-N) AS INTERSECTION OF E-SE FLOW AT H92 CONVERGE. IN TURN THIS IS ALSO WHERE HIGHEST H70 THETA E VALUES ARE TO BE FCSTD. ALTHOUGH THIS IS PRETTY FAR NORTH OF THE CENTER OF HANNA THINK ENHANCED FORCING DVLPS AS ASSOC TRAILING FRONTAL BOUNDARY FROM GUSTAV TRIES TO APPROACH THE RGN FROM THE WEST. THIS IS FAIRLY A REASONABLE SCENARIO WHICH LATEST HPCQPF GUIDANCE IS ALSO IN AGREEMENT. LOOK FOR MOD/HVY RIAN AT TIMES OVRNT INTO SAT (S-N). DRYER AIR WILL START TO BECOME ENTRAINED INTO THE SYSTEM FROM THE SW AT MID LVLS AS SAT PROGRESSES PUSHING AREA OF HEAVIER RAINS TO OVER THE NNE SECTION OF THE CWA WITH TRAILING BAROCLINIC LEAF. ATTM...THINK BETWEEN 3-5 INCHES ON AVG WILL OCCUR OVER NWRN 2/3RDS OF THE CWA WITH HANNA (LOCALLY HIGHER AMOUNTS POSSIBLE WHERE ENHANCED BANDING DVLPS). WILL BE ISSUING A FLASH FLOOD WATCH WITH THIS PACKAGE. LITTLE MORE TRICKY WITH MORE OF A CONVECTIVE AIRMASS OVER THE ERN THIRD...WHICH WILL MAKE FOR MORE HIT AND MISS AREAS OF MOD/HVY RAINFALL. ATTM LOOKING AT AN AVG OF 1 TO 3 INCHES TO OCCUR (LOCALLY HIGHER/LOWER AMTS POSSIBLE). AS WITH ANY TROPICAL SYSTEM WITH HIGH 0-1KM SHEAR VALUES...LOOK FOR THE POTENTIAL FOR DAMAGING WINDS AND AN ENHANCED TORNADO THREAT TO DVLP LATE TONIGHT INTO SAT OVER SE THIRD OF THE CWA WITH OUTER RAIN BANDS. SEE LATEST SPC SWODY1 FOR MORE INFO. TROPICAL STORM FORCE WINDS WILL OCCUR OVER THE ERN THIRD OF THE CWA AS HANNA NEARS/PASSES THROUGH THE RGN. SUST WINDS OF 30-40 MPH WITH POTENTIAL GUST TO NEAR 60 MPH WILL OCCUR. FURTHER WEST...WILL ISSUE A TROPICAL STORM WIND WARNING (FOUND IN HLS) FOR ONE COUNTY BUFFER ZONE WEST OF THE CURRENT TROPICAL STORM WATCH/WRNGS HEADLINES TO ACCOUNT FOR GUSTS TO NEAR 40 MPH. FURTHER INLAND SUST WINDS WILL BE ON THE ORDER OF 10 TO 20 MPH WITH HIGHER GUSTS NEAR 35 MPH AT TIMES. PRECIP EVENTUALLY ENDS AS DRYER AIR FILTERS INTO THE RGN SAT NIGHT/SUN AM (SW-NE). && .LONG TERM /MONDAY THROUGH THURSDAY/... WEAK HIGH PRESSURE WILL BUILD IN FROM THE NORTHWEST ON MONDAY IN THE WAKE OF HANNA. MAINLY DRY CONDITIONS MON INTO TUE MRNG. MODELS/HPC HAVE TRENDED SLOWER WITH NEXT COLD FRONT NOW MAINLY LOOKING TO BE A TUE AFTN/EVENG EVENT. HAVE CONTD 30% CHC FOR SHWRS/TSTMS TUE/TUE NGT. THEN GOING DRY ON WED EXCEPT FOR LINGERING 20% POPS CLOSER TO STALLING BNDRY ACRS SOUTHERN ZONES. HIGH TEMPS WILL BE NEAR TO SLIGHTLY ABOVE AVG MON/TUE (MID/UPR 80S)...THEN A BIT COOLER (AT LEAST FOR DAYTIME HIGHS WED/THU WITH MORE CLOUD CVR EXPECTED....AND POSSIBLE APPROACH OF NEXT TROPICAL SYSTEM (IKE) FROM THE SE. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... VFR CNDTNS XCPT FOR LCL IFR AT SBY & ECG THRU 12Z FOR PTCHY FOG. OTW...TAF FCST WILL BE DOMINATED BY HANNA OVER NXT 24-36 HRS. HIGH/MID LVL CLD DECK OVRSPRDS RGN THIS AFTRN. MVFR CNDTNS XPCTD AFTR 21Z OR SO AS SHWRS SPREAD N FROM NC CSTL AREAS. ONLY PLACE I MENTIONED CB IS AT ECG LATE THIS AFTRN. CNDTNS RPDLY DETERIORATE THIS EVE AS IFR CNDTNS OVRSPRD RGN DUE TO RAIN / FOG. WNDS FIRST INCRS ALONG THE SERN CSTL TAF SITES WITH GUSTS AOA 25 KTS XPCTD B4 MIDNIGHT. GUSTY WNDS THEN SPREAD ACROSS RGN BY LATE TONITE. HANNA PROGGED TO MOVE RPDLY ACRS THE AREA SAT WITH GUSTY WNDS & OCNL IFR CIGS AND VSBYS. WINDS SAT NEAR THE COAST MAY REACH 25-35 WITH GUSTS TO 50 KNOTS AND OVER RIC IN THE 15-30 KNOT RANGE. CONDS WILL IMPROVE FROM S TO N LATE SAT AND SAT NIGHT. MAINLY VFR SHOULD PREVAIL INTO MID WEEK BUT A FEW SHOWERS MAY ACCOOMPANY THE NEXT COLD FRONT AROUND TUE. && .MARINE... TRPLCL HEADLINES REMAIN IN PLACE AS HANNA MOVES NE AND AFFECTS RGN FROM LATE TONIGHT THRU SAT EVE. WND GRIDS CONT TO FOLLOW TPC TRACK. WINDS STEADILY INCREASE TO TRPLCL STORM FORCE AFTR 06Z SAT STARTING OVER THE CURRITUCK SND/SRN COASTAL WATERS...THEN OVER THE SRN CHES BAY AND PRHAPS EVENTUALLY MAKING IT TO THE NRN COASTAL WATERS BY LATE MRNG/ERLY AFTN SAT. SEAS WILL ALSO BECOME VERY HAZARDOUS ON SAT...UP TO 11-15 FT OVER THE CSTL WATERS AND 4-5 FT OVER THE BAY...WITH MOUTH OF THE BAY WAVES APPRCHG 8 FT. STORM SURGE BTWN 2 TO 4 FEET ABV NRML TIDE LEVELS XPCTD...ALONG WITH LARGE AND DANGEROUS BATTERING WAVES XPCTD SAT ALONG THE BEACHES OF NORTHEAST NORTH CAROLINA. COASTAL FLOODING WILL BE GREATEST AROUND THE TIMES OF HIGH TIDE WHICH WILL OCCUR ERLY SAT AFTRN. HANNA RPDLY PULLS NE OF MARINE AREA LATER SAT NGT. IPROVING CNDTNS EXPCTD SUN. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH SATURDAY EVENING FOR MDZ021>023. TROPICAL STORM WATCH FOR MDZ021>025. NC...TROPICAL STORM WARNING FOR NCZ015>017-030>032-102. FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH SATURDAY EVENING FOR NCZ012. TROPICAL STORM WIND WARNING FROM 2 AM TO 2 PM EDT SATURDAY FOR NCZ012>014. VA...TROPICAL STORM WARNING FOR VAZ077-078-084>086-089>091-093>100. FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH SATURDAY EVENING FOR VAZ048-049-060>090-092. TROPICAL STORM WIND WARNING FROM 2 AM TO 2 PM EDT SATURDAY FOR VAZ072>074-076-081>083-088-092. TROPICAL STORM WATCH FOR VAZ075. MARINE...TROPICAL STORM WARNING FOR ANZ630>633-652-654-656-658-670. TROPICAL STORM WATCH FOR ANZ650. && $$ SYNOPSIS...CCW NEAR TERM...CCW SHORT TERM...CCW LONG TERM...LKB AVIATION...MPR MARINE...MPR md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 358 AM EDT FRI SEP 5 2008 .SYNOPSIS... HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH THIS MORNING...PROVIDING CONTINUED DRY CONDITIONS THIS EVENING. HANNA IS EXPECTED TO APPROACH THE SOUTHEAST COAST...MAKING LANDFALL ON THE SOUTHEAST COAST SATURDAY MORNING....BEFORE ACCELERATING NORTHEASTWARD TO ATLANTIC CANADA BY LATE SUNDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... CHANGES TO HEADLINES ANTICIPATED AFTER CONFERENCE CALL THIS MORNING WITH NHC. GFS/RUC IN DECENT AGREEMENT WITH RESPECT TO ENHANCED IR IMAGERY OF BANDING DVLMNT ON THE OUTER FRINGES OF HANNA. DECENT FORCING WITH HIGHER MOISTURE FLUX VALUES DVLPS AS OUTER BAND OF HANNA TO THE MOVES CLOSER TO THE CWA FROM THE SSE THIS MORNING. HIGHS TODAY MAINLY IN THE MID TO UPR 80S...WITH LOWER 80S NEAR/ALONG THE IMMEDIATE COASTLINE. FIRST OUTER BAND OF SHRAS/ISOL TSRA WILL LIKELY MOVE THROUGH THE CWA THIS AFTN/EVE WITH A DRY SLOT DVLPG BEHIND INITIAL BAND LATE EVE/ERLY OVRNT. LOOK FOR AN AVG OF A TENTH TO A QUARTER OF AN INCH WITH ITS PASSAGE...BUT SOME AREAS COULD SEE HIGHER AMOUNTS POSSIBLY NEARING AN INCH. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/... GFS SHOWING A GOOD DEAL OF MOISTURE FLUX DIV DVLPG BTWN 03Z-14Z OVER SWRN 2/RDS OF THE CWA (S-N) AS INTERSECTION OF E-SE FLOW AT H92 CONVERGE. IN TURN THIS IS ALSO WHERE HIGHEST H70 THETA E VALUES ARE TO BE FCSTD. ALTHOUGH THIS IS PRETTY FAR NORTH OF THE CENTER OF HANNA THINK ENHANCED FORCING DVLPS AS ASSOC TRAILING FRONTAL BOUNDARY FROM GUSTAV TRIES TO APPROACH THE RGN FROM THE WEST. THIS IS FAIRLY A REASONABLE SCENARIO WHICH LATEST HPCQPF GUIDANCE IS ALSO IN AGREEMENT. DRYER AIR STARTS TO BECOME ENTRAINED INTO THE SYSTEM FROM THE SW AT MID LVLS AS SAT PROGRESSES PUSHING AREA OF HEAVIER RAINS TO OVER THE NNE SECTION OF THE CWA WITH TRAILING BAROCLINIC LEAF. ATTM...THINK BETWEEN 3-5 INCHES ON AVG WILL OCCUR OVER NWRN 2/3RDS OF THE CWA WITH HANNA (LOCALLY HIGHER AMOUNTS POSSIBLE WHERE ENHANCED BANDING DVLPS). WILL BE ISSUING A FLASH FLOOD WATCH WITH THIS PACKAGE. LITTLE MORE TRICKY WITH MORE OF A CONVECTIVE AIRMASS OVER THE ERN THIRD...WHICH WILL MAKE FOR MORE HIT AND MISS AREAS OF MOD/HVY RAINFALL. ATTM LOOKING AT AN AVG OF 1 TO 3 INCHES TO OCCUR (LOCALLY HIGHER/LOWER AMTS POSSIBLE). AS WITH ANY TROPICAL SYSTEM WITH HIGH 0-1KM SHEAR VALUES...LOOK FOR THE POTENTIAL FOR DAMAGING WINDS AND AN ENHANCED TORNADO THREAT TO DVLP LATE TONIGHT INTO SAT OVER SE THIRD OF THE CWA WITH OUTER RAIN BANDS. SEE LATEST SPC SWODY1 FOR MORE INFO. TROPICAL STORM FORCE WINDS WILL OCCUR OVER THE ERN THIRD OF THE CWA AS HANNA NEARS/PASSES THROUGH THE RGN. SUST WINDS OF 30-40 MPH WITH POTENTIAL GUST TO NEAR 60 MPH WILL OCCUR. FURTHER WEST...WILL ISSUE A TROPICAL STORM WIND WARNING (FOUND IN HLS) FOR ONE COUNTY BUFFER ZONE WEST OF THE CURRENT TROPICAL STORM WATCH/WRNGS HEADLINES TO ACCOUNT FOR GUSTS TO NEAR 40 MPH. FURTHER INLAND SUST WINDS WILL BE ON THE ORDER OF 10 TO 20 MPH WITH HIGHER GUSTS NEAR 35 MPH AT TIMES. PRECIP EVENTUALLY ENDS AS DRYER AIR FILTERS INTO THE RGN SAT NIGHT/SUN AM (SW-NE). && .LONG TERM /MONDAY THROUGH THURSDAY/... WEAK HIGH PRESSURE WILL BUILD IN FROM THE NORTHWEST ON MONDAY IN THE WAKE OF HANNA. MAINLY DRY CONDITIONS MON INTO TUE MRNG. MODELS/HPC HAVE TRENDED SLOWER WITH NEXT COLD FRONT NOW MAINLY LOOKING TO BE A TUE AFTN/EVENG EVENT. HAVE CONTD 30% CHC FOR SHWRS/TSTMS TUE/TUE NGT. THEN GOING DRY ON WED EXCEPT FOR LINGERING 20% POPS CLOSER TO STALLING BNDRY ACRS SOUTHERN ZONES. HIGH TEMPS WILL BE NEAR TO SLIGHTLY ABOVE AVG MON/TUE (MID/UPR 80S)...THEN A BIT COOLER (AT LEAST FOR DAYTIME HIGHS WED/THU WITH MORE CLOUD CVR EXPECTED....AND POSSIBLE APPROACH OF NEXT TROPICAL SYSTEM (IKE) FROM THE SE. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... VFR CNDTNS XCPT FOR LCL IFR AT SBY & ECG THRU 12Z FOR PTCHY FOG. OTW...TAF FCST WILL BE DOMINATED BY HANNA OVER NXT 24-36 HRS. HIGH/MID LVL CLD DECK OVRSPRDS RGN THIS AFTRN. MVFR CNDTNS XPCTD AFTR 21Z OR SO AS SHWRS SPREAD N FROM NC CSTL AREAS. ONLY PLACE I MENTIONED CB IS AT ECG LATE THIS AFTRN. CNDTNS RPDLY DETERIORATE THIS EVE AS IFR CNDTNS OVRSPRD RGN DUE TO RAIN / FOG. WNDS FIRST INCRS ALONG THE SERN CSTL TAF SITES WITH GUSTS AOA 25 KTS XPCTD B4 MIDNIGHT. GUSTY WNDS THEN SPREAD ACROSS RGN BY LATE TONITE. HANNA PROGGED TO MOVE RPDLY ACRS THE AREA SAT WITH GUSTY WNDS & OCNL IFR CIGS AND VSBYS. WINDS SAT NEAR THE COAST MAY REACH 25-35 WITH GUSTS TO 50 KNOTS AND OVER RIC IN THE 15-30 KNOT RANGE. CONDS WILL IMPROVE FROM S TO N LATE SAT AND SAT NIGHT. MAINLY VFR SHOULD PREVAIL INTO MID WEEK BUT A FEW SHOWERS MAY ACCOOMPANY THE NEXT COLD FRONT AROUND TUE. && .MARINE... TRPLCL HEADLINES REMAIN IN PLACE AS HANNA MOVES NE AND AFFECTS RGN FROM LATE TONIGHT THRU SAT EVE. WND GRIDS CONT TO FOLLOW TPC TRACK. WINDS STEADILY INCREASE TO TRPLCL STORM FORCE AFTR 06Z SAT STARTING OVER THE CURRITUCK SND/SRN COASTAL WATERS...THEN OVER THE SRN CHES BAY AND PRHAPS EVENTUALLY MAKING IT TO THE NRN COASTAL WATERS BY LATE MRNG/ERLY AFTN SAT. SEAS WILL ALSO BECOME VERY HAZARDOUS ON SAT...UP TO 11-15 FT OVER THE CSTL WATERS AND 4-5 FT OVER THE BAY...WITH MOUTH OF THE BAY WAVES APPRCHG 8 FT. STORM SURGE BTWN 2 TO 4 FEET ABV NRML TIDE LEVELS XPCTD...ALONG WITH LARGE AND DANGEROUS BATTERING WAVES XPCTD SAT ALONG THE BEACHES OF NORTHEAST NORTH CAROLINA. COASTAL FLOODING WILL BE GREATEST AROUND THE TIMES OF HIGH TIDE WHICH WILL OCCUR ERLY SAT AFTRN. HANNA RPDLY PULLS NE OF MARINE AREA LATER SAT NGT. IPROVING CNDTNS EXPCTD SUN. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH SATURDAY EVENING FOR MDZ021>023. TROPICAL STORM WATCH FOR MDZ021>025. NC...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH SATURDAY EVENING FOR NCZ012. TROPICAL STORM WIND WARNING FROM 2 AM TO 2 PM EDT SATURDAY FOR NCZ012>014. TROPICAL STORM WARNING FOR NCZ015>017-030>032-102. VA...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH SATURDAY EVENING FOR VAZ048-049-060>090-092. TROPICAL STORM WATCH FOR VAZ075-077-078-084>086-089>091- 093>100. TROPICAL STORM WIND WARNING FROM 2 AM TO 2 PM EDT SATURDAY FOR VAZ072>074-076-081>083-088-092. MARINE...TROPICAL STORM WATCH FOR ANZ630>632-650-652-654-656. TROPICAL STORM WARNING FOR ANZ633-658. && $$ SYNOPSIS...CCW NEAR TERM...CCW SHORT TERM...CCW LONG TERM...LKB AVIATION...MPR MARINE...MPR md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1158 PM EDT SAT SEP 6 2008 LATEST UPDATE...AVIATION... .SYNOPSIS...(400 PM EDT SAT SEP 6 2008) AN UPPER LEVEL DISTURBANCE OVER THE CENTRAL PLAINS WILL MOVE NORTHEAST AND CROSS SOUTHERN LOWER MICHIGAN LATE TONIGHT. THIS FEATURE WILL BRING AN INCREASED CHANCE OF RAIN AFTER MIDNIGHT AND EARLY SUNDAY MORNING... PARTICULARLY SOUTH OF INTERSTATE 96. A FRONTAL BOUNDARY WILL APPROACH FROM THE WEST SUNDAY NIGHT THEN STALL FROM SOUTHERN LOWER MICHIGAN TO THE CENTRAL PLAINS ON MONDAY. A LOW PRESSURE SYSTEM WILL FORM AND INTENSIFY ALONG THIS FRONT MONDAY NIGHT... BRINGING ANOTHER INCREASED CHANCE OF RAIN TO SOUTHERN AND CENTRAL LOWER MICHIGAN. && .SHORT TERM...(1150 AM EDT SAT SEP 6 2008) (TONIGHT THROUGH MONDAY NIGHT) RECENT MODEL RUNS HAVE BEEN CONVERGING ON A SOLUTION OF A HIGHER PROBABILITY OF RAIN SHOWERS LATE TONIGHT AND SUNDAY MORNING OVER THE SRN CWFA. THIS IS IN RESPONSE TO STRONG UPR LEVEL DIVERGENCE AND MID LEVEL FGEN WITHIN A COUPLED JET STRUCTURE ALOFT. THIS RAIN APPEARS TO MOVE OUT OF THE AREA BY 18Z SUNDAY WITH DRY WEATHER LIKELY THEREAFTER. THE NEXT BIG WEATHER MAKER APPEARS TO TAKE AIM ON THE AREA MONDAY AFTERNOON AND NIGHT. A FRONTAL BOUNDARY WILL BE SITUATED FROM LOWER MICHIGAN INTO THE CENTRAL PLAINS DURING THIS TIME AND WILL SHARPEN AS H5 TROUGH DIGS UPSTREAM. MODELS ARE NOT IN GREAT AGREEMENT ON THE TIMING... TRACK... AND STRENGTH OF SFC WAVE MOVING NE ALONG THE FRONT. ATTM PREFER THE ECMWF SOLN WHICH HAS BEEN VERY CONSISTENT. TEMPS/CLOUDS/POPS ARE VERY TRICKY ON MONDAY SINCE SHARPENING FRONTAL BOUNDARY WILL PROBABLY BE RIGHT OVER THE CWFA. THIS MAY LEAD TO COOL AND SHOWERY CONDITIONS IN THE NRN CWFA AND MUCH WARMER AND DRY CONDITIONS IN THE SOUTH. WILL HAVE POPS RANGING FROM 30 PCT IN THE SE CWFA TO 50 PCT IN THE NW MONDAY... INCREASING TO LIKELY /60 PCT/ OVER THE ENTIRE CWFA MONDAY NIGHT. COULD BE ANOTHER GOOD SOAKING RAIN ALTHOUGH NOT NEARLY THE QPF AMOUNTS WE SAW FROM GUSTAV. && .LONG TERM...(400 PM EDT SAT SEP 6 2008) TUESDAY THROUGH SATURDAY) COOLER AIR WILL BE MOVING INTO THE CWA AS THE EXTENDED PERIOD BEGINS TUESDAY. SHOWERS WILL END OVER THE ERN CWA TUESDAY MORNING...THEN WE/LL HAVE A COUPLE OF DRY DAYS BEFORE THE SFC HIGH MOVES EAST AND ANOTHER LOW HEADS TOWARD LOWER MICHIGAN. THE SOUTH FLOW AHEAD OF IT WILL BOOST TEMPS BACK INTO THE MID 70S. WE/LL KEEP TSRA/SHRA IN THE GRIDS THURSDAY AND FRIDAY AS THE FRONT MOVES THROUGH AND THEN THE IMPRESSIVE CLOSED LOW FOLLOWS. INSTABILITY DOESN/T LOOK ALL THAT IMPRESSIVE...BUT SOME OF THE JUICE FOR CONVECTIVE DEVELOPMENT WILL BE MADE UP BY THE STRONG MOISTURE CONVERGENCE ALONG THE FRONT. DRY WX EXPECTED SATURDAY. && .MARINE...(400 PM EDT SAT SEP 6 2008) WINDS/WAVES SHOULD STAY BELOW SMALL CRAFT ADVISORY CRITERIA THROUGH MONDAY. MONDAY NIGHT AND TUESDAY MAY TURN VERY ROUGH ON LAKE MICHIGAN DEPENDING ON INTENSITY... TIMING... AND TRACK OF DEVELOPING/DEEPENING LOW PRESSURE SYSTEM ALONG THE STALL FRONTAL BOUNDARY. && .AVIATION...(1158 PM EDT SAT SEP 6 2008) THE AREA OF RAIN OVER EASTERN IOWA HAS MOVED EAST NORTHEAST INTO NORTH CENTRAL ILLINOIS BY 11 PM. THIS AREA WILL RACE NORTHEAST INTO SOUTHERN LOWER MICHIGAN AFTER MIDNIGHT TONIGHT. THAT WILL BRINGING LIGHT TO AT TIMES MODERATE RAIN TO AREAS... NEAR AND SOUTH OF INTERSTATE 96... BETWEEN 4 AM AND 9 AM SUNDAY MORNING. THIS IS THANKS TO COUPLED JET DYNAMICS THAT WILL MOVE ACROSS LOWER MICHIGAN IN THE 8 AM TIME FRAME OF SUNDAY. THAT WILL BRING THE ENHANCED PRECIPITATION ACROSS MOST OF THE SOUTH HALF OF LOWER MICHIGAN. NOW...ADD THE LAKE EFFECT TO THIS. THE 6C 850 MB MOVES INTO THE LAKE SHORE AREAS BY 12Z SUNDAY. THAT IN COMBINATION WITH THE 18C SURFACE LAKE TEMP (COASTWATCH) WILL CREATE SOME LAKE INSTABILITY TOO. THUS AS BOTH THE RUC AND NAM SHOW...THERE WILL BE A LAKE ENHANCED PRECIPITATION AREA WEST OF US-131 TONIGHT THANK TO LAKE ENHANCEMENT. AS I WRITE THIS... SHOWERS WERE ALREADY FORMING WEST OF SAUGATUCK. I HAVE TO BELIEVE THE COMBINATION OF THE DYNAMICS AND LAKE ENHANCEMENT WILL RESULT IN MVFR CIGS/VIS ACROSS THE TAF SITES. I COULD EVEN SEE IFR FOR A TIME BTW 12Z AND 15Z AT MOST OF THE TAF SITES (ONLY MKG IS TO FAR NORTHWEST FOR THIS). ONCE THE SYSTEM MOVES THROUGH CLEARING SHOULD OCCUR (2 PM). HOWEVER THE CU RULE SHOWS ENOUGH LOW LEVEL MOISTURE FOR BROKEN CU COVERAGE IN THE AFTERNOON. MODEL SOUNDS SHOW THIS TOO. THE EQUILIBRIUM LEVEL ON MOST MODEL SOUNDINGS IN THE 18Z TO 21Z TIME FRAME ARE NEAR 15000 FT. THAT BY THE WAY REACHES THE -10C ISOTHERM. ISOLATED SHOWERS WOULD NOT BE OUT THE QUESTION THEN EITHER. THE LAKE EFFECT ENHANCEMENT COULD BEST THAT. BOTTOM LINE HERE IT THE MOSTLY LIKELY TIME FOR SOLID VFR IS FROM NOW TILL 09Z AT MOST TAF SITES. MORE SHOWERS AND LAKE ENHANCEMENT ARE POSSIBLE EARLY MONDAY MORNING AS THE NEXT COLD PUSH MOVES IN. && .HYDROLOGY...(400 PM EDT SAT SEP 6 2008) QPF AMOUNTS TONIGHT ARE PROGGED TO BE A QUARTER INCH OR LESS... WITH MAX AMOUNTS EXPECTED TO BE SOUTH OF A LINE FROM SOUTH HAVEN TO LANSING. THIS WILL HAVE LITTLE OR NO IMPACT ON HYDRO. THE SYSTEM ON MONDAY NIGHT LOOKS TO HAVE THE POTENTIAL OF PRODUCING WIDESPREAD AMOUNTS OF AROUND ONE HALF INCH... WITH LOCAL AMOUNTS OF UP TO ONE INCH POSSIBLE. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ SYNOPSIS: MEADE SHORT TERM: MEADE LONG TERM: 93 MARINE: MEADE AVIATION: WDM HYDROLOGY: MEADE mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 735 PM EDT SAT SEP 6 2008 UPDATED FOR THE 00Z TAF ISSUANCE .SYNOPSIS (ISSUED AT 439 PM EDT)... 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW LARGE SCALE UPR TROF CENTERED OVER CNTRL NAMERICA BTWN RDGS OFF THE W AND E COASTS. SHRTWV RESPONSIBLE FOR SHRA LAST NGT/THIS MRNG IS HEADING NEWD INTO ONTARIO THIS AFTN...AND SUBSIDENCE IN THE WAKE OF THIS SYS HAS CONTRIBUTED TO THE DVLPMNT OF A MID LVL INVRN ARND H75 AS SHOWN ON 12Z MPX RAOB/15Z TAMDAR SDNG FM RHI THAT IS LIKELY SPREADING NEWD INTO THE FA BECAUSE THE 12Z RAOB FM GRB SHOWED INVRN BASE AT H65. DESPITE PLENTY OF LINGERING LLVL MSTR AS SHOWN ON RECENT TAMDAR SDNGS...THE STRENGTHENING/LOWERING INVRN AS HINTED AS WELL ON RUC FCST SDNGS HAS CAUSED MOST OF THE SHRA TO DSPT BY 16Z. THE ONLY EXCEPTIONS ARE OVER THE ERN ZNS...WHERE BACKEDGE OF LINGERING DEEPER MSTR HAS NOT QUITE PASSED...AND OVER THE W CLOSER TO A WEAKER MID LVL INVRN AS SHOWN ON THE 12Z INL RAOB. THE W IS ALSO CLOSER TO A WEAK SFC LO PRESENT JUST W OF CMX AT 15Z. ALTHOUGH THE LOWERING INVRN HAS TENDED TO DIMINISH THE SHRA...THE TRAPPED LLVL MSTR BLO THE INVRN BASE HAS RESULTED IN QUITE A BIT OF LO CLD. WHERE SKIES HAD CLRD EARLIER OVER THE SCNTRL...DAYTIME HTG RESULTED IN THE DVLPMNT OF MORE LO CLD. THE BACK EDGE OF THIS LO CLD EXTENDS W INTO CNTRL MN AND S INTO SCNTRL WI. THE 12Z BIS/ABR RAOBS DEPICT A DRIER SFC-H8 LYR WHERE THERE IS AN ABSENCE OF LO CLD NEAR SFC HI PRES RDG AXIS. HOWEVER...THERE WAS SOME FOG THIS MRNG IN THAT AREA. ANOTHER FAIRLY STRONG SHRTWV ROTATING THRU THE MEAN TROF IN THE PLAINS IS DIGGING THRU SASKATCHEWAN EARLY THIS AFTN. ANOTHER SHRTWV ROUNDING THE BASE OF THE UPR TROF IS NOTED OVER IA. && .SHORT TERM (TNGT/SUN) (ISSUED AT 439 PM EDT)... MAIN FCST CONCERNS DURING THIS TIME ARE CLD AND SHRA TRENDS/FOG CHCS TNGT... THEN TIMING/COVG OF PCPN ON SUN ASSOCIATED WITH SHRTWV NOW DROPPING THRU SASKATCHEWAN. FOR TNGT...SHRTWV NOW OVER IA IS PROGGED TO MOVE ENE JUST S OF THE FA...SO NO CONCERNS ABOUT PCPN ASSOCIATED WITH IT EVEN THOUGH SOME HI CLD ON ITS NRN FRINGES MAY IMPACT MAINLY THE SCNTRL AND E THRU MUCH OF THE NGT. OTRW...LARGER SCALE H85-5 QVECTOR DVGC IS FCST TO DOMINATE THRU THE NGT...WITH SFC HI PRES RDG NOW TO THE W EXPECTED TO NOSE INTO THE FA OVERNGT. DESPITE THESE EXPECTATIONS...NAM PERSISTS IN SHOWING LGT QPF OVER THE NCTRL AND E. LOCAL HI RES MODELS ALSO DEPICT SOME ISOLD SHRA IMPACTING MAINLY THE NCNTRL AND ERN ZNS DESPITE THE SUSPECTED LARGER SCALE TRENDS. THE GFS SHOWS LTL IN THE WAY OF QPF. GIVEN THIS DISPARITY IN FCSTS...OPTED TO MAINTAIN SOME LO CHC POPS OVER THE NRN TIER BEFORE LOSS OF DIURNAL HTG CAUSES GOING SHRA TO WEAKEN IN ABSENCE OF SGNFT DYNAMIC FORCING. THE SHRA WL PERSIST LONGEST OVER THE E CLOSER TO DEPARTING LO CENTER MOVING INTO ERN LK SUP/MORE RESILIENT CYC FLOW. SINCE FOG WAS OBSVD UPSTREAM LAST NGT CLOSE TO THIS RDG AXIS...WL ADD MENTION OF SOME FOG LATE TNGT UNDER THE UPR DRYING OVER THE INTERIOR W/SCNTRL CLOSER TO HI CENTER PASSING TO THE S. SHARPER PRES GRADIENT/WNW FLOW OVER THE N WL MINIMIZE FOG POTENTIAL...BUT SUSTAIN LO CLD. LOWEST MIN TEMPS OVER THE INTERIOR NEAR THE WI BORDER WHERE LO LVL WINDS ARE MOST LIKELY TO DECOUPLE. ON SUN...SHRTWV OVER SASKATCHEWAN THIS AFTN IS PROGGED TO REACH NRN MN BY 00Z MON. SFC COLD FNT ASSOCIATED WITH THIS FEATURE WILL REACH THE CNTRL ZNS LATE IN THE DAY. EXPECT THE DAY TO START ON THE DRY SIDE WITH FCST SDNGS SHOWING A DRY ATMOSPHERE...BUT APRCH OF SHRTWV/ FNT IN THE AFTN WL INCREASE PCPN CHCS. NEGATIVES FOR PCPN INCLUDE ABUNDANT DRY AIR...SFC DWPTS THIS AFTN AHEAD OF THE FNT IN THE DAKOTAS ARE IN THE LOW 40S...AND RELATIVELY WEAK H85 CNVGC ALG THE BNDRY AS WELL AS ABSENCE OF ANY LARGER SCALE JET FORCING/UPR DVGC. DESPITE THE NEGATIVES...INTRODUCED CHC TS GIVEN OBSVD LTG STRIKES UPSTREAM AHD OF THE FNT...GFS/NAM FCST H7-5 LAPSE RATES APRCHG 7C/KM...AND FVRBL PEAK HTG TIME OF DAY FOR ARRIVAL OF BNDRY. MODIFIED GFS FCST SDNG FOR SFC T/TD OF 70/40 YIELDS A MODEST SBCAPE UP TO 500 J/KG...BUT STEEP LLVL LAPSE RATES/UNIDIRECTIONAL WLY FLOW MAY RESULT IN GUSTY WINDS UNDER THE HEAVIER SHRA. .LONG TERM (SUN NIGHT THRU SAT) (ISSUED AT 439 PM EDT)... SUN NIGHT...SHORTWAVE BRINGING PCPN TO THE FCST AREA SUN WILL MOVE E OF THE FCST AREA BY 12Z MON. WILL THUS DIMINISH POPS FROM W TO E OVERNIGHT SUN NIGHT. THUNDER POTENTIAL WILL ALSO END WITH BOUNDARY LAYER COOLING. ON MON...IF THERE ARE ANY LINGERING -SHRA OVER THE E...THEY WILL END IN THE MORNING. ATTENTION THEN TURNS TO NEXT SHORTWAVE DROPPING INTO THE PLAINS MON AND THEN LIFTING NE INTO THE GREAT LAKES MON NIGHT. NAM/GFS (ESPECIALLY GFS) ARE STRONGER AND MORE NRLY WITH ASSOCIATED SFC LOW LIFTING INTO THE GREAT LAEKS. 12Z UKMET/ECWMF OFFER A MORE SUPPRESSED WEAKER SFC LOW WHILE THE GLOBAL CANADIAN SHOWS VERY LITTLE SFC REFLECTION AT ALL. AT THIS POINT... WILL LEAN TOWARD THE MORE CONSISTENT ECMWF SOLUTION WHICH IS STRONGLY SUPPORTED BY THE UKMET. WEAK GLOBAL CANADIAN SOLUTION ALSO SUGGESTS LEANING AWAY FROM THE GFS/NAM AT THIS TIME. IMPRESSIVE UPPER DIVERGENCE IN RIGHT ENTRANCE OF 300MB JET WILL YIELD A SIGNIFICANT STRIPE OF PCPN LIFTING INTO THE GREAT LAKES N OF SFC LOW TRACK. HOWEVER...IN FAVORING THE FLATTER ECMWF/UKMET SOLUTION...BULK OF THAT RAIN WILL PASS BY TO THE SE OF THE FCST AREA MON NIGHT. SHOULD A MORE NRLY SOLUTION PAN OUT...A MUCH NEEDED WIDESPREAD RAINFALL WOULD DEVELOP OVER THE FCST AREA. GRIDS WILL BE STRUCTURED TO SHOW HIGHEST POPS SE (STILL JUST CHC CATEGORY) WITH DRY WEATHER NW MON AFTN/NIGHT. WED THRU SAT...MEDIUM RANGE MODELS (ECMWF/UKMET/CANADIAN/GFS) ARE IN GOOD AGREEMENT ON THE OVERALL PATTERN OVER NAMERICA DURING THIS TIME FRAME. ALL FEATURE A PROGRESSIVE REGIME ACROSS THE NRN CONUS TO THE S OF THE POLAR VORTEX CENTERING ITSELF OVER NCNTRL CANADA. THERE IS ONE MAIN SHORTWAVE TROF OF INTEREST THAT WILL SWING ACROSS THE NRN CONUS...AND MEDIUM RANGE MODELS HAVE BEEN AND CONTINUE TO BE IN QUITE GOOD AGREEMENT ON TIMING THE TROF. GIVEN AGREEMENT ON THE OVERALL PATTERN AND INDIVIDUAL FEATURES...CONFIDENCE DURING THE WED-SAT PERIOD IS ABOVE NORMAL. SFC HIGH PRES OVER THE WRN GREAT LAKES TUE NIGHT WILL SLIP QUICKLY TO THE E. WITH HIGH PRES OVER THE FCST AREA FOR AT LEAST THE EARLY PART OF TUE NIGHT...WILL GO AT OR BLO THE LOW END OF MOS GUIDANCE FOR MINS...ESPECIALLY OVER THE E. MAY SEE SOME PATCHY FROST INTERIOR CNTRL AND E. ON WED...SFC LOW PRES TROF WILL EMERGE OVER THE WRN PLAINS IN RESPONSE TO THE APPROACHING SHORTWAVE TROF. WAA PATTERN WILL DEVELOP WED...THOUGH IT APPEARS THE BEST WAA WILL STILL REMAIN W AND SW OF THE FCST AREA THRU THE DAY. IN ADDITION...LOW-LEVEL FLOW REMAINS SOMEWHAT ANTICYCLONIC...ESPECIALLY AS DEPICTED IN THE ECWMF. FOR THESE REASONS...CONSIDERED REMOVING POPS FROM ALL BUT WRN LAKE SUPERIOR. FOR NOW...WILL TRIM POPS BACK FROM THE INHERITED FCST TO INCLUDE JUST THE FAR WRN FCST AREA WED AFTN. SHRA/TSRA WILL THEN PROGRESS E ACROSS THE FCST AREA WED NIGHT/THU. WITH 12HR HEIGHT FALLS NEARING 100M AND A NICE RIBBON OF DEEP MOISTURE...THIS SYSTEM OFFERS THE POTENTIAL FOR WIDESPREAD MUCH NEEDED PCPN THOUGH QUICK MOVEMENT WILL WORK TO LIMIT AMOUNTS. FOR NOW...DID NOT GO ANY HIGHER THAN THE HIGH CHC RANGE AS MODEL TIMING CHANGES OF 12HRS OR MORE ARE CERTAINLY POSSIBLE 4-6 DAYS OUT INTO MODEL RUNS. EVENTUALLY...HIGH POPS SHOULD BE REQUIRED ONCE TIMING IS CERTAIN. ALTHOUGH SOME -SHRA/SPRINKLES MAY LINGER INTO FRI MORNING IN BACKSIDE CYCLONIC FLOW...WILL DRY FCST OUT FOR FRI/SAT IN THE WAKE OF SYSTEM. AS FOR TEMPS...READINGS THRU THE PERIOD SHOULD NOT STRAY TOO FAR FROM NORMAL FOR EARLY/MID SEPT. && .AVIATION (FOR THE 00Z TAF ISSUANCE)... MVFR CEILINGS WILL LIKELY REDEVELOP TEMPORARILY AT CMX AS WESTERLY UPSLOPE WINDS TAKE HOLD OVERNIGHT. EXPECTE IMPROVING CONDITIONS AT SAW AS LIGHT SHOWERS EXIT. HOWEVER...WILL NEED TO MONITOR THE THE POSSIBILITY OF FOG AT SAW. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... EXPECT LOW PRESSURE OVER WESTERN UPPER MICHIGAN TO DRIFT INTO EASTERN LAKE SUPERIOR OVERNIGHT. IN ITS WAKE...A WEAK 30.0 INCH RIDGE OF HIGH PRESSURE WILL CROSS LAKE SUPERIOR LATE TONIGHT INTO SUNDAY MORNING. WINDS OVER THE LAKE WILL BE LIGHT DURING THIS PERIOD. A 29.9 INCH LOW PRESSURE OVER NORTHWEST ONTARIO EARLY SUNDAY MORNING WILL MOVE OVER JAMES BAY LATE SUNDAY NIGHT...DRAGGING A COLD FRONT ACROSS LAKE SUPERIOR. NORTHWEST WINDS BEHIND THIS FRONT WILL INCREASE TO 30 KNOTS OVER THE EAST HALF OF LAKE SUPERIOR. A LOW WILL FORM OVER NORTHERN ILLINOIS MONDAY EVENING AND DEEPEN TO AS IT MOVES INTO WESTERN QUEBEC ON TUESDAY. LOOK FOR HIGH PRESSURE TO BUILD OVER THE CENTRAL PLAINS AND MINNESOTA TUESDAY AFTERNOON AND MOVE TO THE EASTERN GREAT LAKES WEDNESDAY EVENING. A LOW PRESSURE TROUGH... EXTENDING FROM WESTERN ONTARIO TO THE CENTRAL PLAINS WEDNESDAY EVENING...WILL CROSS LAKE SUPERIOR THURSDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN...NONE. LAKE SUPERIOR...NONE. LAKE MICHIGAN...NONE. && $$ SYNOPSIS/SHORT TERM...KC LONG TERM...ROLFSON AVIATION...KF MARINE...KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 439 PM EDT SAT SEP 6 2008 .SYNOPSIS... 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW LARGE SCALE UPR TROF CENTERED OVER CNTRL NAMERICA BTWN RDGS OFF THE W AND E COASTS. SHRTWV RESPONSIBLE FOR SHRA LAST NGT/THIS MRNG IS HEADING NEWD INTO ONTARIO THIS AFTN...AND SUBSIDENCE IN THE WAKE OF THIS SYS HAS CONTRIBUTED TO THE DVLPMNT OF A MID LVL INVRN ARND H75 AS SHOWN ON 12Z MPX RAOB/15Z TAMDAR SDNG FM RHI THAT IS LIKELY SPREADING NEWD INTO THE FA BECAUSE THE 12Z RAOB FM GRB SHOWED INVRN BASE AT H65. DESPITE PLENTY OF LINGERING LLVL MSTR AS SHOWN ON RECENT TAMDAR SDNGS...THE STRENGTHENING/LOWERING INVRN AS HINTED AS WELL ON RUC FCST SDNGS HAS CAUSED MOST OF THE SHRA TO DSPT BY 16Z. THE ONLY EXCEPTIONS ARE OVER THE ERN ZNS...WHERE BACKEDGE OF LINGERING DEEPER MSTR HAS NOT QUITE PASSED...AND OVER THE W CLOSER TO A WEAKER MID LVL INVRN AS SHOWN ON THE 12Z INL RAOB. THE W IS ALSO CLOSER TO A WEAK SFC LO PRESENT JUST W OF CMX AT 15Z. ALTHOUGH THE LOWERING INVRN HAS TENDED TO DIMINISH THE SHRA...THE TRAPPED LLVL MSTR BLO THE INVRN BASE HAS RESULTED IN QUITE A BIT OF LO CLD. WHERE SKIES HAD CLRD EARLIER OVER THE SCNTRL...DAYTIME HTG RESULTED IN THE DVLPMNT OF MORE LO CLD. THE BACK EDGE OF THIS LO CLD EXTENDS W INTO CNTRL MN AND S INTO SCNTRL WI. THE 12Z BIS/ABR RAOBS DEPICT A DRIER SFC-H8 LYR WHERE THERE IS AN ABSENCE OF LO CLD NEAR SFC HI PRES RDG AXIS. HOWEVER...THERE WAS SOME FOG THIS MRNG IN THAT AREA. ANOTHER FAIRLY STRONG SHRTWV ROTATING THRU THE MEAN TROF IN THE PLAINS IS DIGGING THRU SASKATCHEWAN EARLY THIS AFTN. ANOTHER SHRTWV ROUNDING THE BASE OF THE UPR TROF IS NOTED OVER IA. && .SHORT TERM (TNGT/SUN)... MAIN FCST CONCERNS DURING THIS TIME ARE CLD AND SHRA TRENDS/FOG CHCS TNGT... THEN TIMING/COVG OF PCPN ON SUN ASSOCIATED WITH SHRTWV NOW DROPPING THRU SASKATCHEWAN. FOR TNGT...SHRTWV NOW OVER IA IS PROGGED TO MOVE ENE JUST S OF THE FA...SO NO CONCERNS ABOUT PCPN ASSOCIATED WITH IT EVEN THOUGH SOME HI CLD ON ITS NRN FRINGES MAY IMPACT MAINLY THE SCNTRL AND E THRU MUCH OF THE NGT. OTRW...LARGER SCALE H85-5 QVECTOR DVGC IS FCST TO DOMINATE THRU THE NGT...WITH SFC HI PRES RDG NOW TO THE W EXPECTED TO NOSE INTO THE FA OVERNGT. DESPITE THESE EXPECTATIONS...NAM PERSISTS IN SHOWING LGT QPF OVER THE NCTRL AND E. LOCAL HI RES MODELS ALSO DEPICT SOME ISOLD SHRA IMPACTING MAINLY THE NCNTRL AND ERN ZNS DESPITE THE SUSPECTED LARGER SCALE TRENDS. THE GFS SHOWS LTL IN THE WAY OF QPF. GIVEN THIS DISPARITY IN FCSTS...OPTED TO MAINTAIN SOME LO CHC POPS OVER THE NRN TIER BEFORE LOSS OF DIURNAL HTG CAUSES GOING SHRA TO WEAKEN IN ABSENCE OF SGNFT DYNAMIC FORCING. THE SHRA WL PERSIST LONGEST OVER THE E CLOSER TO DEPARTING LO CENTER MOVING INTO ERN LK SUP/MORE RESILIENT CYC FLOW. SINCE FOG WAS OBSVD UPSTREAM LAST NGT CLOSE TO THIS RDG AXIS...WL ADD MENTION OF SOME FOG LATE TNGT UNDER THE UPR DRYING OVER THE INTERIOR W/SCNTRL CLOSER TO HI CENTER PASSING TO THE S. SHARPER PRES GRADIENT/WNW FLOW OVER THE N WL MINIMIZE FOG POTENTIAL...BUT SUSTAIN LO CLD. LOWEST MIN TEMPS OVER THE INTERIOR NEAR THE WI BORDER WHERE LO LVL WINDS ARE MOST LIKELY TO DECOUPLE. ON SUN...SHRTWV OVER SASKATCHEWAN THIS AFTN IS PROGGED TO REACH NRN MN BY 00Z MON. SFC COLD FNT ASSOCIATED WITH THIS FEATURE WILL REACH THE CNTRL ZNS LATE IN THE DAY. EXPECT THE DAY TO START ON THE DRY SIDE WITH FCST SDNGS SHOWING A DRY ATMOSPHERE...BUT APRCH OF SHRTWV/ FNT IN THE AFTN WL INCREASE PCPN CHCS. NEGATIVES FOR PCPN INCLUDE ABUNDANT DRY AIR...SFC DWPTS THIS AFTN AHEAD OF THE FNT IN THE DAKOTAS ARE IN THE LOW 40S...AND RELATIVELY WEAK H85 CNVGC ALG THE BNDRY AS WELL AS ABSENCE OF ANY LARGER SCALE JET FORCING/UPR DVGC. DESPITE THE NEGATIVES...INTRODUCED CHC TS GIVEN OBSVD LTG STRIKES UPSTREAM AHD OF THE FNT...GFS/NAM FCST H7-5 LAPSE RATES APRCHG 7C/KM...AND FVRBL PEAK HTG TIME OF DAY FOR ARRIVAL OF BNDRY. MODIFIED GFS FCST SDNG FOR SFC T/TD OF 70/40 YIELDS A MODEST SBCAPE UP TO 500 J/KG...BUT STEEP LLVL LAPSE RATES/UNIDIRECTIONAL WLY FLOW MAY RESULT IN GUSTY WINDS UNDER THE HEAVIER SHRA. .LONG TERM (SUN NIGHT THRU SAT)... SUN NIGHT...SHORTWAVE BRINGING PCPN TO THE FCST AREA SUN WILL MOVE E OF THE FCST AREA BY 12Z MON. WILL THUS DIMINISH POPS FROM W TO E OVERNIGHT SUN NIGHT. THUNDER POTENTIAL WILL ALSO END WITH BOUNDARY LAYER COOLING. ON MON...IF THERE ARE ANY LINGERING -SHRA OVER THE E...THEY WILL END IN THE MORNING. ATTENTION THEN TURNS TO NEXT SHORTWAVE DROPPING INTO THE PLAINS MON AND THEN LIFTING NE INTO THE GREAT LAKES MON NIGHT. NAM/GFS (ESPECIALLY GFS) ARE STRONGER AND MORE NRLY WITH ASSOCIATED SFC LOW LIFTING INTO THE GREAT LAEKS. 12Z UKMET/ECWMF OFFER A MORE SUPPRESSED WEAKER SFC LOW WHILE THE GLOBAL CANADIAN SHOWS VERY LITTLE SFC REFLECTION AT ALL. AT THIS POINT... WILL LEAN TOWARD THE MORE CONSISTENT ECMWF SOLUTION WHICH IS STRONGLY SUPPORTED BY THE UKMET. WEAK GLOBAL CANADIAN SOLUTION ALSO SUGGESTS LEANING AWAY FROM THE GFS/NAM AT THIS TIME. IMPRESSIVE UPPER DIVERGENCE IN RIGHT ENTRANCE OF 300MB JET WILL YIELD A SIGNIFICANT STRIPE OF PCPN LIFTING INTO THE GREAT LAKES N OF SFC LOW TRACK. HOWEVER...IN FAVORING THE FLATTER ECMWF/UKMET SOLUTION...BULK OF THAT RAIN WILL PASS BY TO THE SE OF THE FCST AREA MON NIGHT. SHOULD A MORE NRLY SOLUTION PAN OUT...A MUCH NEEDED WIDESPREAD RAINFALL WOULD DEVELOP OVER THE FCST AREA. GRIDS WILL BE STRUCTURED TO SHOW HIGHEST POPS SE (STILL JUST CHC CATEGORY) WITH DRY WEATHER NW MON AFTN/NIGHT. WED THRU SAT...MEDIUM RANGE MODELS (ECMWF/UKMET/CANADIAN/GFS) ARE IN GOOD AGREEMENT ON THE OVERALL PATTERN OVER NAMERICA DURING THIS TIME FRAME. ALL FEATURE A PROGRESSIVE REGIME ACROSS THE NRN CONUS TO THE S OF THE POLAR VORTEX CENTERING ITSELF OVER NCNTRL CANADA. THERE IS ONE MAIN SHORTWAVE TROF OF INTEREST THAT WILL SWING ACROSS THE NRN CONUS...AND MEDIUM RANGE MODELS HAVE BEEN AND CONTINUE TO BE IN QUITE GOOD AGREEMENT ON TIMING THE TROF. GIVEN AGREEMENT ON THE OVERALL PATTERN AND INDIVIDUAL FEATURES...CONFIDENCE DURING THE WED-SAT PERIOD IS ABOVE NORMAL. SFC HIGH PRES OVER THE WRN GREAT LAKES TUE NIGHT WILL SLIP QUICKLY TO THE E. WITH HIGH PRES OVER THE FCST AREA FOR AT LEAST THE EARLY PART OF TUE NIGHT...WILL GO AT OR BLO THE LOW END OF MOS GUIDANCE FOR MINS...ESPECIALLY OVER THE E. MAY SEE SOME PATCHY FROST INTERIOR CNTRL AND E. ON WED...SFC LOW PRES TROF WILL EMERGE OVER THE WRN PLAINS IN RESPONSE TO THE APPROACHING SHORTWAVE TROF. WAA PATTERN WILL DEVELOP WED...THOUGH IT APPEARS THE BEST WAA WILL STILL REMAIN W AND SW OF THE FCST AREA THRU THE DAY. IN ADDITION...LOW-LEVEL FLOW REMAINS SOMEWHAT ANTICYCLONIC...ESPECIALLY AS DEPICTED IN THE ECWMF. FOR THESE REASONS...CONSIDERED REMOVING POPS FROM ALL BUT WRN LAKE SUPERIOR. FOR NOW...WILL TRIM POPS BACK FROM THE INHERITED FCST TO INCLUDE JUST THE FAR WRN FCST AREA WED AFTN. SHRA/TSRA WILL THEN PROGRESS E ACROSS THE FCST AREA WED NIGHT/THU. WITH 12HR HEIGHT FALLS NEARING 100M AND A NICE RIBBON OF DEEP MOISTURE...THIS SYSTEM OFFERS THE POTENTIAL FOR WIDESPREAD MUCH NEEDED PCPN THOUGH QUICK MOVEMENT WILL WORK TO LIMIT AMOUNTS. FOR NOW...DID NOT GO ANY HIGHER THAN THE HIGH CHC RANGE AS MODEL TIMING CHANGES OF 12HRS OR MORE ARE CERTAINLY POSSIBLE 4-6 DAYS OUT INTO MODEL RUNS. EVENTUALLY...HIGH POPS SHOULD BE REQUIRED ONCE TIMING IS CERTAIN. ALTHOUGH SOME -SHRA/SPRINKLES MAY LINGER INTO FRI MORNING IN BACKSIDE CYCLONIC FLOW...WILL DRY FCST OUT FOR FRI/SAT IN THE WAKE OF SYSTEM. AS FOR TEMPS...READINGS THRU THE PERIOD SHOULD NOT STRAY TOO FAR FROM NORMAL FOR EARLY/MID SEPT. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... EXPECT MVFR CIGS TO PERSIST AT LEAST OCCASIONALLY AT BOTH SITES THE REST OF THIS AFTN WITH LINGERING LLVL MSTR SHOWN ON RECENT TAMDAR SDNGS/SMALL SFC DWPT DEPRESSIONS IN THE PRESENCE OF DIURNAL HTG. BUT THE TREND SHOULD BE FOR A GRDL IMPROVEMENT WITH THIS SFC HTG LIFTING THE CIG BASE. MVFR CIGS WL LIKELY REDVLP AT CMX TNGT WITH EXPECTED UPSLOPE WLY FLOW AND DIURNAL COOLING BEFORE THE ARRIVAL OF DRIER AIR NOW IN WRN MN TENDS TO BREAK UP ANY LO CLD. SAW WL BE MORE SHELTERED FM THIS FLOW...SO RADIATION FOG IS A POSSIBILITY THERE. THEN VFR CONDITIONS WL BE THE RULE AFT ANY MRNG FOG BURNS OFF AT SAW ON SUN THRU 18Z. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... EXPECT LOW PRESSURE OVER WESTERN UPPER MICHIGAN TO DRIFT INTO EASTERN LAKE SUPERIOR OVERNIGHT. IN ITS WAKE...A WEAK 30.0 INCH RIDGE OF HIGH PRESSURE WILL CROSS LAKE SUPERIOR LATE TONIGHT INTO SUNDAY MORNING. WINDS OVER THE LAKE WILL BE LIGHT DURING THIS PERIOD. A 29.9 INCH LOW PRESSURE OVER NORTHWEST ONTARIO EARLY SUNDAY MORNING WILL MOVE OVER JAMES BAY LATE SUNDAY NIGHT...DRAGGING A COLD FRONT ACROSS LAKE SUPERIOR. NORTHWEST WINDS BEHIND THIS FRONT WILL INCREASE TO 30 KNOTS OVER THE EAST HALF OF LAKE SUPERIOR. A LOW WILL FORM OVER NORTHERN ILLINOIS MONDAY EVENING AND DEEPEN TO AS IT MOVES INTO WESTERN QUEBEC ON TUESDAY. LOOK FOR HIGH PRESSURE TO BUILD OVER THE CENTRAL PLAINS AND MINNESOTA TUESDAY AFTERNOON AND MOVE TO THE EASTERN GREAT LAKES WEDNESDAY EVENING. A LOW PRESSURE TROUGH... EXTENDING FROM WESTERN ONTARIO TO THE CENTRAL PLAINS WEDNESDAY EVENING...WILL CROSS LAKE SUPERIOR THURSDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN...NONE. LAKE SUPERIOR...NONE. LAKE MICHIGAN...NONE. && $$ SYNOPSIS/SHORT TERM...KC LONG TERM...ROLFSON AVIATION...KC MARINE...KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 350 PM EDT SAT SEP 6 2008 .SYNOPSIS.../ISSUED AT 348 PM/ A WEAK LOW PRESSURE SYSTEM WILL MOVE OVER LAKE SUPERIOR TONIGHT BEFORE EXITING INTO ONTARIO TOMORROW. THIS FEATURE WILL GENERATE A FEW LIGHT RAIN SHOWERS...OVER NORTHERN MICHIGAN THROUGH TONIGHT. A SECOND STORM SYSTEM...MOVING OVER CENTRAL CANADA AND THE UPPER MIDWEST...WILL SWING OVER THE GREAT LAKES SUNDAY NIGHT. THIS SYSTEM IS EXPECTED TO GENERATE ANOTHER ROUND OF SHOWERS... OVER THE NORTHERN LAKES SUNDAY NIGHT AND MONDAY. && .SHORT TERM.../ISSUED AT 348 PM/...THIS EVENING AND TONIGHT LATEST RUC ANALYSIS AND VIS/IR/WV/RADAR IMAGERY SHOW WEAK LOW PRESSURE CENTERED NEAR MQT WITH AN EQUALLY AS WEAK SURFACE TROUGH/CONVERGENCE AXIS BISECTING THE FORECAST AREA FROM NORTH TO SOUTH. WITHIN A LOOSE LOW LEVEL THETAE AXIS AHEAD OF THE TROUGH...DIURNAL HEATING HAS CONTRIBUTED TO SPOTTY SHOWER ACTIVITY...MOST PREVALENT ACROSS EASTERN UPPER AND THE FAR NORTHERN LOWER LAKE HURON SHORELINE. THE WARM WATERS OF THE NORTHERN GREAT LAKES HAVE GIVEN A BOOST TO THESE SHOWERS AS DELTA T/S ARE AROUND 11C. WITH THE LOCAL CONVERGENCE ALONG THE TROUGH AND OVER-WATER INSTABILITY...A COUPLE WATERSPOUTS HAVE BEEN SIGHTED NEAR THE STRAITS AND NORTHERN LAKE HURON SHORELINE. AN ADDITIONAL TROUGH EXTENDS WEST FROM THE SURFACE LOW TOWARDS NORTHERN WISCONSIN...WHICH IS ALSO SUPPORTING SHOWER ACTIVITY. FARTHER SOUTHWEST...A FAIRLY POTENT WAVE IS MOVING ACROSS NEBRASKA/IOWA WHICH HAS EYES ON THE SOUTHERN GREAT LAKES. PRECIP CHANCES ARE THE MAIN FORECAST CONCERNS TONIGHT. TONIGHT...WEAK SURFACE LOW OVER THE NORTH-CENTRAL U.P. WILL SHIFT NE ACROSS LAKE SUPERIOR. LOOSELY DEFINED LOW LEVEL THETAE AXIS EMANATING FROM THIS LOW WILL EXIT INTO LAKE HURON BY MID-EVENING...ENDING ANY SPOTTY SHOWER AND WATERSPOUT THREAT ACROSS NORTHERN LOWER FOR A PERIOD. THINGS NOT QUITE AS CLEAR ACROSS EASTERN UPPER WHERE LOW LEVEL CONVERGENCE IS A LITTLE BETTER AS A RESULT OF THE SURFACE LOW NEARBY. THERE MAY VERY WELL BE A BREAK IN THE ACTION ACROSS EASTERN UPPER DURING THE EVENING AS WELL...AS MID-LEVEL DRY AIR AND ISENTROPIC DESCENT ARRIVE FOR A LITTLE WHILE. NAM/GFS BOTH POINT TOWARDS A SECONDARY TROUGH DROPPING SE ACROSS NORTHERN LAKE MICHIGAN AND EASTERN UPPER AFTER MIDNIGHT. IF THIS MORNING WAS ANY INDICATION...INSTABILITY GENERATED BY DELTA T/S AROUND 11C OVER NORTHERN LAKE MICHIGAN MAY PROVIDE A BOOST TO ANY SHOWERS THAT DO DEVELOP ALONG THE TROUGH. OTHERWISE...DECENT LOOKING SHORTWAVE OVER NEBRASKA WILL MOVE INTO THE SOUTHERN GREAT LAKES BY MORNING. MID AND HIGH CLOUDS WILL SPREAD ACROSS NORTHERN MICHIGAN AHEAD OF THIS SYSTEM DURING THE EVENING AND OVERNIGHT. DEEPEST MOISTURE FROM THIS SYSTEM WILL REMAIN TO THE SOUTH BUT PROBABLY CLOSE ENOUGH TO WARRANT AN ISOLATED SHOWER ALONG AND SOUTH OF M-55 VERY LATE. LOWS IN THE MID 40S TO LOW 50S. MPC && .LONG TERM.../ISSUED AT 348 PM/...TONIGHT AND BEYOND INTERESTINGLY...TURN THE SWITCH TO METEOROLOGICAL FALL AND THE WEATHER PATTERN SEEMS TO FOLLOW SUIT...FEATURING A MUCH MORE ACTIVE NORTHERN STREAM FLOW OVER THE NORTHERN CONUS. THIS PATTERN IS EXPECTED TO CONTINUE FOR THE FORESEEABLE FUTURE...FEATURING BROAD NORTHERN CONUS AND WESTERN LAKES MID LEVEL TROUGHINESS...WHICH WILL BE RIDDLED WITH RELATIVELY FAST MOVING...HARD TO TIME SHORTWAVES. ALTHOUGH MUCH UNCERTAINTY PLAGUES THE EXTENDED...SOME USEFUL INFORMATION CAN BE ASCERTAINED...NAMELY A CONTINUATION OF THE RELATIVELY WET PATTERN AND MAINTENANCE OF THE COOL EARLY SEPTEMBER TEMPERATURES. ALTHOUGH FORECAST CONFIDENCE REGARDING SPECIFIC SHORTWAVE TIMING DECREASES NEARLY EXPONENTIALLY FARTHER OUT IN THE EXTENDED... CONFIDENCE SOMEWHAT HIGHER (ALTHOUGH STILL NOT AS HIGH AS ONE WOULD LIKE) THROUGH MONDAY NIGHT AS NOAM WATER VAPOR ANALYSIS CONFIRMS LATEST MODEL GUIDANCE THAT TRIFECTA OF DECENT SHORTWAVES WILL AFFECT THE GREAT LAKES...ONE EXITING STAGE RIGHT DURING SUNDAY MORNING... WITH PROGRESSIVELY STRONGER ONES CUTTING THROUGH THE REGION SUNDAY NIGHT AND MONDAY NIGHT. ALTHOUGH MOISTURE PROFILES NOT OVERWHELMING THROUGH THIS PERIOD...DYNAMICS SHOULD MORE THAN COMPENSATE... BRINGING PERIODIC RAIN CHANCES...ESPECIALLY DURING PASSAGE OF AFOREMENTIONED WAVES. STILL LOOKING LIKE BETTER DYNAMICS WITH SUNDAYS WAVE WILL PASS SOUTH OF THE REGION...AND HAVE CONTINUED TO FOCUS BETTER POTENTIAL IN OUR SOUTHERN ZONES (STILL LOW CHANCE AT BEST). INTERESTINGLY...FARTHER NORTH...PASSAGE OF SUBTLE SURFACE TROUGH OVER LAKE MICHIGAN DURING THE MORNING...AUGMENTED WITH POSSIBLE LAND BREEZE CONVERGENCE AXIS...MOISTURE FLUX FROM THE RELATIVELY WARM LAKE WATERS (DELTA T/S ON THE ORDER OF 11C TO 12C)...AND MID LEVEL WEAK SHEAR AXIS MAY BE ENOUGH TO KICK OFF A SCATTERED LINE OF SHOWERS OVER THE WATER TOWARDS MORNING...WHICH PROPAGATE INLAND AS SYNOPTIC WIND REGIME OVERWHELMS THE LAND BREEZE. A SIMILAR SCENARIO UNFOLDED THIS PAST MORNING...WITH CLEAR EVIDENCE OF ADDED LAKE MICHIGAN SUPPORT AS SHOWERS ADVANCED FROM WISCONSIN. OTHERWISE...HAVE REMOVED POPS FOR THE AFTERNOON HOURS WITH SOME SEMBLANCE OF LOW AMPLITUDE RIDGE AXIS PIVOTING INTO THE AREA. NEXT WAVE SLATED TO DROP SOUTHEAST SUNDAY NIGHT...THIS TIME WITH BETTER DYNAMICS PASSING OVER EASTERN UPPER MICHIGAN AND POINTS NORTH. MUCH LIKE SUNDAY...JUST NOT OVERLY SOLD ON SHOWER POTENTIAL WITH LIMITED MOISTURE PROFILES AND BETTER MID LEVEL SUPPORT ESSENTIALLY PASSING NORTH OF THE AREA. WILL TAPER CHANCE POPS FROM NORTH TO SOUTH...WITH SOME WEST/EAST TIMING. WILL KEEP SLIGHT CHANCE THUNDER MENTION WITH 900MB LIFTED PARCELS YIELDING NEARLY 400 J/KG MEAN LAYER CAPE. PROBABLY THE MOST INTERESTING WEATHER OF THE EXTENDED BEGINS LATE MONDAY NIGHT...CONTINUING THROUGH TUESDAY MORNING...AS STRONG SHORTWAVE MAKES THE TURN TO THE EAST NORTHEAST OVER THE CENTRAL PLAINS...WITH SIGHTS SET ON THE GREAT LAKES REGION. LATEST NAM-WRF AND GFS GUIDANCE HAVE REALLY AMPLIFIED THIS SYSTEM...DROPPING SURFACE PRESSURE TO SUB 1000MB AS IT PASSES THROUGH NORTHERN MICHIGAN. OTHER GUIDANCE REMAINS MUCH LESS AGGRESSIVE...AND HENCE FARTHER SOUTHEAST WITH THE SURFACE LOW (IN FACT...12Z GEM HAS ESSENTIALLY NO SURFACE REFLECTION). IF AMERICAN GUIDANCE IS TO BE BELIEVED...RAIN...LOCALLY HEAVY (OVER AN INCH WITH QPF FIELDS) WILL QUICKLY OVERSPREAD THE AREA LATE MONDAY AFTERNOON...CONTINUING THROUGH MONDAY NIGHT. LOOKING AT MID LEVEL HEIGHT FIELDS...IT APPEARS BOTH THE NAM-WRF AND GFS ARE UNREALISTICALLY AGGRESSIVE WITH DOWNSTREAM RIDGE RESPONSE (TOO QUICKLY BUILDING HEIGHTS) AFTER PASSAGES OF LATE WEEKEND SHORTWAVES. THIS ALLOWS UPSTREAM SHORTWAVE TO OVER-AMPLIFY AND PUSH FARTHER NORTHEAST. IN LIGHT OF THE ABOVE...WILL SIDE WITH THE MORE CONSERVATIVE GUIDANCE...FEATURING LIKELY POPS OVER THE SOUTH HALF OF THE AREA AND MUCH LESS RAINFALL. HAVE LINGERED LIGHT SHOWER MENTION INTO TUESDAY MORNING AS SYSTEM PULLS OFF TO THE EAST AND WEAK NORTHWEST FLOW LAKE EFFECT RAIN SHOWERS POSSIBLY DEVELOP AS 850MB TEMPERATURES DROP TO THE SINGLE DIGITS. LOOKING FARTHER OUT...AS MENTIONED...QUESTIONS ABOUND LATER IN THE FORECAST PERIOD. IN GENERAL...STILL LIKE THE IDEA OF A DRY MIDWEEK PERIOD AS SURFACE AND MID LEVEL RIDGE AXES CREST THE REGION. BEYOND THIS...MODELS HINTING AT ANOTHER FAIRLY STRONG SHORTWAVE PASSING THROUGH LATE IN THE WEEK...BRINGING ANOTHER CHANCE OF SHOWERS. HOWEVER...WITH HURRICANE IKE NOW SLATED TO PASS INTO THE GULF OF MEXICO (PER LATEST NHC GUIDANCE)...WOULD EXPECT THIS FEATURE TO AT LEAST TRY TO FLEX ITS MUSCLE ON OVERALL CONUS FLOW REGIME...POSSIBLY PLAYING SOME HAVOC ON AMPLITUDE AND TIMING OF THE NORTHERN STREAM SHORTWAVE. GIVEN UNCERTAINTIES...FELT IT WOULD BE A FORECAST INJUSTICE TO TRY ANY SORT OF TIMING...AND HAVE TOOK THE SIMPLE APPROACH OF MAINTAINING FORECAST CONTINUITY WITH POP AND WEATHER GRIDS AND RUNNING WITH HPC GUIDANCE ALL OTHERS. TEMPERATURES THROUGH THE EXTENDED WILL REMAIN NEAR TO SLIGHTLY BELOW SEASONAL NORMALS...WITH HIGHS IN THE 60S TO LOW 70S AND OVERNIGHT LOWS GENERALLY IN THE 40S AND 50S. MSB && .MARINE.../ISSUED AT 348 PM/ SHOWERS AND ISOLATED WATERSPOUTS CONTINUE TO FORM ALONG A SURFACE CONVERGENCE AXIS...AND HAVE BEEN GETTING A BOOST FROM THE WARM LAKE WATERS OF THE NORTHERN GREAT LAKES. SHOWER...ALONG WITH THE THREAT OF WATERSPOUTS...WILL BE POSSIBLE ALONG THIS AXIS ACROSS NE LOWER AND FAR EASTERN UPPER UNTIL THIS AXIS MOVES OVER THE OPEN WATERS OF LAKE HURON THIS EVENING. OTHERWISE...NO OTHER MARINE HAZARDS ARE EXPECTED SINCE WINDS WILL REMAIN LIGHT TONIGHT. MPC && .AVIATION.../ISSUED AT 100 PM/...VALID FOR 18Z TAFS CHALLENGING FORECAST OVER THE NEXT 24 HOURS. WEAK SURFACE LOW OVER CENTRAL UPPER MICHIGAN WILL TRACK NE OVER LAKE SUPERIOR WITH ITS TRAILING COOL FRONT/SURFACE TROUGH CROSSING NORTHERN LOWER THROUGH THE AFTERNOON. SHOWERS WILL REMAIN SPOTTY WITH LIMITED CHANCES OF IMPACT ON THE TAF SITES. SECONDARY SURFACE TROUGH WILL PASS ACROSS THE AREA EARLY TOMORROW MORNING. HARD TO SAY IF ANY LOW CLOUDS/FOG WILL ACCOMPANY THIS TROUGH. CERTAINLY IS POSSIBLE...JUDGING BY WHAT OCCURRED UPSTREAM THIS MORNING. BEST CHANCES WOULD APPEAR TO BE AT PLN AND WILL TREND TOWARDS LOWER VSBYS AND CIGS...BUT WILL REFRAIN FROM GOING LOCK/STOCK/AND BARREL DUE TO POOR MODEL GUIDANCE. SO...WILL KEEP VFR GOING THROUGH THE TAF PERIOD EXCEPT AT PLN. MPC && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. LH...NONE. LS...NONE. && $$ mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 126 AM EDT SAT SEP 6 2008 UPDATED AVIATION DISCUSSION FOR 06Z TAFS .SYNOPSIS... ISSUED AT 325 PM EDT 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR TROFFING CENTERED OVER CNTRL NAMERICA BTWN RDGS ON THE E AND W COASTS. SHRTWV/DEEP MSTR ASSOCIATED WITH THE REMNANTS OF GUSTAV ARE MOVING RDPLY NE THRU SE CAN...BUT A SUBTLE LO PRES TROF REMAINS OVER THE FA ON ITS WRN FLANK. RECENT TAMDAR SDNGS SHOW A GOOD AMT OF LLVL MSTR REMAINS OVER THE UPR GRT LKS UNDER THE SUBSIDENCE INVRN ARND H75 LEFT IN ITS WAKE. SO QUITE A BIT OF SC IS PRESENT DESPITE DIURNAL HTG THAT HAS LIFTED CLD BASE AND ENDED ANY -DZ THAT WAS OBSVD EARLIER. THE COMBINATION OF SOME SUBSIDENCE OVER LK SUP RELATED TO THE LK BREEZE CIRCULATION AND THE ARRIVAL OF SOMEWHAT DRIER AIR FM THE NW THAT WAS SHOWN BEST ON THE 00Z RAOBS FM INL/YPL HAS TENDED TO BREAK UP THE CLD MORE AGGRESSIVELY THERE AND NEAR THE LK SHORES. NEXT SHRTWV OF CONCERN IS PRESENTLY MOVING ACRS NRN MN ALONG WITH AN ASSOCIATED SFC LO. THERE IS QUITE A BIT OF CLD TO THE N AND W OF THIS LO...AND THE ERN EDGE OF THE THICKER CLD IS MOVING TOWARD WRN LK SUP. SOME SCT -SHRA ARE AS FAR E AS DLH IN AXIS OF HIER SPECIFIC HUMIDITY SHOWN ON THE 300K ISENTROPIC SFC (ARND H7) BY THE 12Z NAM F6. BUT OVERALL PCPN COVG SEEMS LIMITED BY THE DRY MID LVLS SHOWN ON THE 12Z MPX RAOB. && .SHORT TERM (TNGT AND SAT)... ISSUED AT 325 PM EDT FOR TNGT...12Z GFS/NAM SHOW SHRTWV NOW OVER NRN MN SHEARING ENEWD AND WEAKENING A BIT TO NEAR ISLE ROYALE BY 12Z SAT AS UPR TROF AXIS REMAINS SITUATED IN THE PLAINS. THE ACCOMPANYING SFC LO IS PROGGED TO REACH THE WRN SHORE OF THE U.P. BOTH MODELS SHOW AXIS OF HIEST SPECIFIC HUMIDITY NOW OVER MN AND ON THE 300K SFC SHIFTING INTO THE W THIS EVNG THEN THE ECNTRL BY 12Z SAT WITH ISENTROPIC LIFT NOTED ON THE 295-305K SFCS/QVECTOR CNVGC IN THE H85-5 LYR. GFS IS A BIT MORE GENEROUS WITH QPF...BUT PREFER THE SOMEWHAT MORE MODEST NAM GIVEN THE MID LVL DRY AIR SHOWN ON THE 12Z MPX RAOB THAT IS LIMITING PCPN COVG NOW. STILL...HAVE OPTED TO BUMP POPS UP TO 40 BEFORE FAIRLY AGGRESSIVE DRYING ON THE 300K SFC IN THE JET SURGE REGION ON THE SE FLANK OF THE SHRTWV TRACK OVERSPRDS THE FA. GOING FCST MIN TEMPS ARE FAIRLY IN LINE WITH LATEST GFS/ETA/NGM MOS GUIDANCE...SO NO SGNFT CHGS MADE TO GOING FCST. ON SAT...THE DEEPER MSTR ALF WL IMPACT THE ERN ZNS IN THE MRNG BEFORE THE DRYING ON THE 300K SFC IS FCST TO CLR ERY BY 18Z OR SO AS THE SHRTWV NR ISLE ROYALE/SFC LO OVER WRN LK SUP AT 12Z SHIFTS NE INTO ONTARIO. TO THE W...THE FOCUS SHIFTS TO WHETHER ENUF LLVL MSTR WL LINGER TO ALLOW THE REDVLPMNT OF MORE SHRA WITH DIURNAL HTG. IF THE TIME OF YEAR WERE CLOSER TO THE SUMMER SOLSTICE...THAT WOULD BE A REAL CONCERN. OTHER CONSIDERATIONS INCLUDE THE PRESENCE OF LINGERING LO CLD IN THE MRNG WHICH DVLPS WITH THE ARRIVAL OF THE DRYING ALF LATE TNGT AND THAT WOULD LIMIT SFC HTG. CONSIDERING THE MARGINAL LAPSE RATES AND MID LVL DRY AIR EXHIBITED IN GFS/NAM FCST SDNGS IN THE ABSENCE OF DYNAMIC FORCING...BELIEVE REDVLPMNT OF DIURNAL SHRA IN THE AFTN IS A LO POTENTIAL. SO ELECTED TO CUT GOING GENERAL 30 POP TO NO MORE THAN 20. .LONG TERM (SATURDAY NIGHT THROUGH FRIDAY)... THIS PERIOD REMAINS PLAGUED BY WEAK SHORTWAVES...MAKING SPECIFIC TIMING OF CLOUDS AND PRECIPITATION DIFFICULT. FOR THE LONG TERM THIS RESULTS IN AVERAGE FORECASTER CONFIDENCE IN THE SPECIFICS. LINGERING PRECIPITATION WILL START OFF THIS PERIOD THANKS TO A WEAK SHORTWAVE MOVING THROUGH THE CWA. A SLIGHTLY STRONGER SYSTEM IS FIGURED FOR SUNDAY AND SUNDAY NIGHT...MOVING THROUGH THE UPPER GREAT LAKES. THE POTENTIAL REMAINS FOR THUNDERSTORM ACTIVITY...ALBEIT ISOLATED. A COLD FRONT WILL BE POISED TO MOVE WEST TO EAST OVER UPPER MICHIGAN LATE SUNDAY AFTERNOON THROUGH THE EARLY OVERNIGHT HOURS. THE ENTIRE SYSTEM IS THEN EXPECTED TO STRENTHEN OVER SOUTHEASTERN ONTARIO AND LAKE HURON MONDAY MORNING. THIS SHOULD KEEP NORTH TO NORTHWESTERLY WINDS AND A BETTER CHANCE OF LINGERING CLOUDS ACROSS EASTERN UPPER MICHIGAN INTO AT LEAST MONDAY AFTERNOON. DRY WEATHER CAN THEN BE EXPECTED FOR THE MIDDLE OF THE UPCOMING WORK WEEK...AS HIGH PRESSURE MOVES IN AT THE SURFACE AND A ZONAL FLOW SETS UP AT 500MB. HPC GUIDANCE WAS FOLLOWED PRETTY CLOSELY FOR THIS PERIOD...EXCLUDING SKY COVER WHICH NEEDED TO BE MINIMIZED A LITTLE MORE INITIALLY. THIS WAS HEAVILY BASED ON ENSEMBLES...WITH A LEAN TOWARDS THE 12Z GFS. FOR THE LATTER HALF OF THE WORK WEEK THOUGH...SOUTHWESTERLY FLOW WILL RETURN BRINGING A BETTER CHANCE OF SHOWERS OR THUNDERSTORMS THURSDAY AND FRIDAY. && .AVIATION (FOR THE 06Z TAF ISSUANCE)... -SHRA WHICH HAVE ARRIVED IN THE KCMX VCNTY WILL SPREAD TO KSAW OVER THE NEXT FEW HRS AS LOW PRES MOVES FROM MN TO WRN LAKE SUPERIOR. PER UPSTREAM OBS...EXPECT CONDITIONS INITIALLY TO BE VFR EVEN THOUGH PCPN WILL BE OCCURRING. HOWEVER...AS PCPN DIMINISHES/ENDS...EXPECT MVFR CONDITIONS TO DEVELOP WITH LOW CLOUD/FOG FORMING UNDER ARRIVAL OF DRIER AIR ALOFT...AND ABOVE THE LOW-LEVELS MOISTENED BY PCPN. THERE WILL BE SLOW IMPROVEMENT SAT MORNING WITH CONDITIONS BECOMING VFR IN THE AFTN AND CONTINUING THRU THE END OF THIS FCST PERIOD. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... LOW PRESSURE OVER FAR WESTERN QUEBEC WILL WEAKEN AS IT MOVES OVER NEW BRUNSWICK SATURDAY MORNING WHILE A HIGH PRESSURE RIDGE OVER WESTERN LAKE SUPERIOR THIS EVENING MOVES OVER THE EASTERN GREAT LAKES ON SUNDAY. MEANWHILE...A TROUGH OF LOW PRESSURE WILL CROSS LAKE SUPERIOR SATURDAY. ANOTHER DEEPER LOW PRESSURE TROUGH WILL FOLLOW LATE SUNDAY INTO MONDAY...WITH HIGH PRESSURE BUILDING OVER THE LOWER GREAT LAKES MONDAY. THIS HIGH WILL SHIFT INTO THE EASTERN GREAT LAKES ON WEDNESDAY. WINDS THROUGH THE WEEKEND WILL BE NO HIGHER THAN 20 KNOTS. THE NEXT CHANCE FOR STRONGER WINDS WILL BE ON MONDAY. NORTHWEST WINDS THEN ARE LIKELY TO REACH 25 KNOTS... ESPECIALLY OVER THE EAST HALF...AS HIGH PRESSURE FOLLOWS THE TROUGH INTO THE UPPER GREAT LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN...NONE. LAKE SUPERIOR...NONE. LAKE MICHIGAN...NONE. && $$ SYNOPSIS/SHORT TERM...KC LONG TERM...KF AVIATION...ROLFSON MARINE...KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1021 PM EDT FRI SEP 5 2008 .UPDATE... THE 00Z DTX SOUNDING SHOWED A MUCH STRONGER INVERSION BASED NEAR 850MB THAN INDICATED BY MODEL SOUNDINGS. EVEN THOUGH THE MOIST LAYER IS SOMEWHAT SHALLOW...THE STRENGTH OF THE INVERSION SHOULD KEEP THIS MOISTURE TRAPPED. SATELLITE TRENDS OVER THE LAST HOUR HAVE BEEN SHOWING AN INCREASE IN THE CLOUD COVER. NORTHERLY FLOW AND SHALLOW INSTABILITY OFF LAKE HURON SHOULD ADD SOME LAKE CONTRIBUTION TO THE CLOUDS AS WELL. SO WILL UPDATE TO INCREASE CLOUD COVER A BIT. NORTHERLY DOWNSLOPE FLOW SHOULD STILL ALLOW SOME SIGNIFICANT BREAKS ACROSS THE SAGINAW VALLEY AND POSSIBLY MONROE AND WAYNE COUNTIES. WITH MORE CLOUDS EXPECTED...HAVE INCREASED MIN TEMPS A COUPLE DEGREES. WILL ALSO REMOVE MENTION OF FOG WITH THE EXCEPTION OF THE SAGINAW VALLEY WERE SIGNIFICANT PERIODS OF CLEARING MAY STILL PROMOTE RADIATIONAL FOG DEVELOPMENT. && .PREV DISCUSSION...ISSUED 703 PM EDT FRI SEP 5 2008 AVIATION... WEAK LOW LEVEL DRY AIR ADVECTION FROM THE NORTHWEST HAS BEEN ALLOWING A DIMINISHING TREND TO THE STRATO CU FIELD. BASES HAVE ALSO RISEN TO VFR. THE LOW LEVEL MOISTURE PROFILE ON THE LATEST DTW TAMDAR SOUNDING LENDS MORE SUPPORT TO RUC MODEL SOUNDINGS...WHICH SHOW A LITTLE GREATER DEPTH TO THE LOW LEVEL MOISTURE. WOULD THEREFORE EXPECT SOME REDEVELOPMENT OF A VFR STRATO CU FIELD UNDERNEATH DEVELOPING SUBSIDENCE INVERSION TONIGHT. THE INSTABILITY PROFILE OVER LAKE HURON IS ALSO SUPPORTIVE OF LAKE STRATUS TONIGHT. NORTHERLY FLOW WILL ADVECT THIS STRATUS INLAND...LIKELY IMPACTING FNT AND DTW WITH MVFR CIGS AFTER 09Z. MEANWHILE...NORTH-NORTHWESTERLY DOWNSLOPE FLOW SHOULD MAINTAIN A SCT DECK AT MBS. THE ONSET OF DAYTIME HEATING WILL ALLOW CLOUDS TO SCATTER OUT BY 15Z SUN. PREV DISCUSSION...ISSUED 401 PM EDT FRI SEP 5 2008 SHORT TERM...TONIGHT LOW PRESSURE THAT BROUGHT A COLD FRONT THROUGH THE AREA EARLY THIS MORNING WILL CONTINUE TO TRACK NORTHEAST ACROSS QUEBEC TONIGHT. A FEW SPRINKLES ARE SHOWING UP ON AREA RADARS OUT OF THE DENSE STRATOCU DECK THAT REMAINS OVER SOUTHEAST MICHIGAN. THIS DECK IS CLEARING FROM THE NORTHWEST WITH NORTHERN PORTIONS OF THE CWA EXPECTED TO SEE MOSTLY CLEAR SKIES DEVELOP LATE THIS EVENING. MEANWHILE A LINGERING THERMAL TROUGH EXTENDING BACK FROM THE SURFACE LOW ACROSS LAKE HURON AND LAKE ERIE WILL HELP THE CLOUDS PERSIST THROUGH THE NIGHT IN OUR SOUTHERN AND EASTERN COUNTIES. DESPITE AN OVERALL DRYING TREND IN DEWPOINTS...NORTHERLY WINDS OFF LAKE HURON WILL CONTINUE TO ADD MOISTURE TO THE BOUNDARY LAYER MAKING PATCHY FOG A CONCERN FOR AREAS NEAR THE LAKES TONIGHT. GUIDANCE NUMBERS LOOKED REASONABLE IN THE NORTH WHERE SKIES SHOULD BE MOSTLY CLEAR BUT HAVE GONE A FEW DEGREES ABOVE GUIDANCE IN THE SOUTH WHERE CLOUDS SHOULD HANG ON OVERNIGHT. LONG TERM...SATURDAY THROUGH NEXT FRIDAY UPPER SHORTWAVE SPINNING OVER KS/NE WILL LIFT NORTHEAST AND ACROSS LOWER MICHIGAN EARLY TOMORROW...JUST AHEAD OF AN APPROACHING WEAK SURFACE TROUGH THAT IS CURRENTLY PUSHING INTO NORTHERN MINNESOTA. THIS TROUGH WILL THEN LIFT ACROSS NORTHERN LAKE HURON TOMORROW EVENING. WATER VAPOR IMAGERY INDICATES THIS SHORTWAVE MAY BE A LITTLE STRONGER THAN MODELS SUGGEST. WITH MODELS STREAMING SOME MOISTURE IN AHEAD OF THESE FEATURE TOMORROW...AND GUIDANCE EVEN KICKING OUT SOME POPS...WILL ADD A MENTION OF SHOWERS UP AROUND THE TRI-CITIES FOR TOMORROW AFTERNOON. OTHERWISE...JUST EXPECT INCREASING CLOUDS FOR THE REMAINDER OF SOUTHEAST MICHIGAN TOWARDS AFTERNOON AND EVENING AS THESE FEATURES PASS TO OUR NORTH. TEMPERATURES ARE EXPECTED TO REBOUND BACK UP INTO THE 70S TOMORROW. BROAD UPPER TROUGHING WILL SET UP ACROSS MUCH OF THE NORTHERN U.S. SATURDAY NIGHT...USHERING IN A PERIOD OF FAST ENERGETIC WESTERLY FLOW THAT WILL HOLD OVER THE GREAT LAKES INTO TUESDAY. INDIVIDUAL WAVES THAT WILL EJECT THROUGH THIS FLOW WILL BE HARD TO TIME...BUT LARGER WAVES ARE STILL EXPECTED TO PUSH THROUGH ON SUNDAY AND MONDAY. NAM/GFS IN GOOD AGREEMENT WITH A WEAK WARM FRONT LIFTING UP THROUGH SOUTHERN LOWER MICHIGAN SUNDAY MORNING...AND INTO CENTRAL LOWER MICHIGAN BY LATE AFTERNOON. NAM SHOWS GREAT MOIST ISENTROPIC ASCENT OCCURING EARLY OVER THE SOUTHERN PORTION OF THE FORECAST AREA...THEN LIFTING SLOWLY NORTHWARD THROUGHOUT THE DAY. GFS DIFFERS SLIGHTLY AND KEEPS STRONGER ASCENT LIMITED TO THE TRI-CITIES AND THUMB. WILL HOLD ONTO CHANCE POPS THROUGHOUT THE DAY...WITH THE EXPECTATION OF SEEING MORE ACTIVITY ALONG AND NORTH OF I-69...AT LEAST UNTIL MODELS COME INTO BETTER AGREEMENT. PRECIPITATION SHOULD BE FAIRLY LIGHT. BETTER CHANCE OF PRECIPITATION WILL OCCUR LATE SUNDAY NIGHT AND MONDAY AS THE STRONGEST OF THE UPPER WAVES MOVES THROUGH MICHIGAN AND PUSHES A COLD FRONT THROUGH THE REGION. COLDER AIR WILL CONTINUE TO SPILL INTO THE REGION ON TUESDAY AS THE FRONT EXITS AND A COOL DOME OF HIGH PRESSURE SETTLES IN OVERHEAD. CONDITIONS WILL TURN QUITE FALL-LIKE ON TUESDAY AS H850 TEMPS COOL TO AROUND 5 DEGREES C. THIS SHOULD PROVIDE SURFACE TEMPERATURES THAT STRUGGLE TO REACH EVEN THE UPPER 60S...WITH OVERNIGHT LOWS THEN DROPPING INTO THE 40S JUST ABOUT EVERYWHERE. SOME CONCERN FOR STRATUS DEVELOPMENT TUESDAY BEHIND THE FRONT AS COOL AIR STREAMS OVER THE VERY WARM LAKES. THE ADDITIONAL CLOUD COVER WOULD HAVE AN EFFECT ON TEMPERATURES...AND FORECAST WILL NEED TO BE AJUSTED IF THIS SCENARIO STARTS TO LOOK MORE FAVORABLE HIGH PRESSURE STILL EXPECTED TO HOLD OVER THE REGION INTO WEDNESDAY BEFORE SOUTHERLY FLOW STARTS TO INCREASE AHEAD OF THE NEXT UPPER TROUGH. MEDIUM RANGE MODELS ARE STARTING TO STRUGGLE WITH HOW THEY HANDLE MID-WEEK UPSTREAM ENERGY OVER THE PACIFIC NORTHWEST. HAVE A HIGH DEGREE OF CONFIDENCE WITH THE TROUGH ARRIVING TOWARDS THE END OF THE WEEK...BUT LOW CONFIDENCE WITH DETAILS...AMPLITUDE...AND EXACT TIMING. MARINE... THE PRESSURE GRADIENT WILL CONTINUE TO WEAKEN INTO SATURDAY AS THE LOW PRESSURE SYSTEM THAT MOVED THROUGH THE AREA LAST NIGHT CONTINUES NORTHEAST ACROSS QUEBEC. SUSTAINED WINDS WILL REMAIN AROUND 20 KNOTS ACROSS NORTHERN LAKE HURON WHILE OTHER AREAS HAVE ALREADY STARTED TO SUBSIDE. SMALL CRAFT ADVISORIES HAVE BEEN EXTENDED OVERNIGHT FOR THE OUTER SAGINAW BAY AND INTO SATURDAY ON NEARSHORE AREAS FROM PORT AUSTIN TO PORT SANILAC AS WAVES WILL REMAIN HIGH UNDER NORTHERLY WINDS. CONDITIONS WILL BECOME MORE FAVORABLE FOR BOATING FROM SATURDAY AFTERNOON INTO SUNDAY AS HIGH PRESSURE BUILDS EASTWARD ACROSS THE GREAT LAKES REGION. ANOTHER LOW PRESSURE SYSTEM WILL BRING THE NEXT COLD FRONT THROUGH THE REGION ON MONDAY...POTENTIALLY CREATING MORE UNSTABLE CONDITIONS AS MUCH COOLER AIR FILTERS ACROSS THE WARMER LAKE WATERS. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... SMALL CRAFT ADVISORY...OUTER SAGINAW BAY...UNTIL 4 AM SATURDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO HARBOR BEACH...UNTIL 10 AM SATURDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM HARBOR BEACH TO PORT SANILAC...UNTIL 4 PM SATURDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ UPDATE.......SC AVIATION.....SC SHORT TERM...KEC LONG TERM....HLO MARINE.......KEC 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 MARQUETTE MI 738 PM EDT FRI SEP 5 2008 UPDATED AVIATION DISCUSSION FOR 00Z TAFS .SYNOPSIS... ISSUED AT 325 PM EDT 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR TROFFING CENTERED OVER CNTRL NAMERICA BTWN RDGS ON THE E AND W COASTS. SHRTWV/DEEP MSTR ASSOCIATED WITH THE REMNANTS OF GUSTAV ARE MOVING RDPLY NE THRU SE CAN...BUT A SUBTLE LO PRES TROF REMAINS OVER THE FA ON ITS WRN FLANK. RECENT TAMDAR SDNGS SHOW A GOOD AMT OF LLVL MSTR REMAINS OVER THE UPR GRT LKS UNDER THE SUBSIDENCE INVRN ARND H75 LEFT IN ITS WAKE. SO QUITE A BIT OF SC IS PRESENT DESPITE DIURNAL HTG THAT HAS LIFTED CLD BASE AND ENDED ANY -DZ THAT WAS OBSVD EARLIER. THE COMBINATION OF SOME SUBSIDENCE OVER LK SUP RELATED TO THE LK BREEZE CIRCULATION AND THE ARRIVAL OF SOMEWHAT DRIER AIR FM THE NW THAT WAS SHOWN BEST ON THE 00Z RAOBS FM INL/YPL HAS TENDED TO BREAK UP THE CLD MORE AGGRESSIVELY THERE AND NEAR THE LK SHORES. NEXT SHRTWV OF CONCERN IS PRESENTLY MOVING ACRS NRN MN ALONG WITH AN ASSOCIATED SFC LO. THERE IS QUITE A BIT OF CLD TO THE N AND W OF THIS LO...AND THE ERN EDGE OF THE THICKER CLD IS MOVING TOWARD WRN LK SUP. SOME SCT -SHRA ARE AS FAR E AS DLH IN AXIS OF HIER SPECIFIC HUMIDITY SHOWN ON THE 300K ISENTROPIC SFC (ARND H7) BY THE 12Z NAM F6. BUT OVERALL PCPN COVG SEEMS LIMITED BY THE DRY MID LVLS SHOWN ON THE 12Z MPX RAOB. && .SHORT TERM DISCUSSION (TNGT AND SAT)... ISSUED AT 325 PM EDT FOR TNGT...12Z GFS/NAM SHOW SHRTWV NOW OVER NRN MN SHEARING ENEWD AND WEAKENING A BIT TO NEAR ISLE ROYALE BY 12Z SAT AS UPR TROF AXIS REMAINS SITUATED IN THE PLAINS. THE ACCOMPANYING SFC LO IS PROGGED TO REACH THE WRN SHORE OF THE U.P. BOTH MODELS SHOW AXIS OF HIEST SPECIFIC HUMIDITY NOW OVER MN AND ON THE 300K SFC SHIFTING INTO THE W THIS EVNG THEN THE ECNTRL BY 12Z SAT WITH ISENTROPIC LIFT NOTED ON THE 295-305K SFCS/QVECTOR CNVGC IN THE H85-5 LYR. GFS IS A BIT MORE GENEROUS WITH QPF...BUT PREFER THE SOMEWHAT MORE MODEST NAM GIVEN THE MID LVL DRY AIR SHOWN ON THE 12Z MPX RAOB THAT IS LIMITING PCPN COVG NOW. STILL...HAVE OPTED TO BUMP POPS UP TO 40 BEFORE FAIRLY AGGRESSIVE DRYING ON THE 300K SFC IN THE JET SURGE REGION ON THE SE FLANK OF THE SHRTWV TRACK OVERSPRDS THE FA. GOING FCST MIN TEMPS ARE FAIRLY IN LINE WITH LATEST GFS/ETA/NGM MOS GUIDANCE...SO NO SGNFT CHGS MADE TO GOING FCST. ON SAT...THE DEEPER MSTR ALF WL IMPACT THE ERN ZNS IN THE MRNG BEFORE THE DRYING ON THE 300K SFC IS FCST TO CLR ERY BY 18Z OR SO AS THE SHRTWV NR ISLE ROYALE/SFC LO OVER WRN LK SUP AT 12Z SHIFTS NE INTO ONTARIO. TO THE W...THE FOCUS SHIFTS TO WHETHER ENUF LLVL MSTR WL LINGER TO ALLOW THE REDVLPMNT OF MORE SHRA WITH DIURNAL HTG. IF THE TIME OF YEAR WERE CLOSER TO THE SUMMER SOLSTICE...THAT WOULD BE A REAL CONCERN. OTHER CONSIDERATIONS INCLUDE THE PRESENCE OF LINGERING LO CLD IN THE MRNG WHICH DVLPS WITH THE ARRIVAL OF THE DRYING ALF LATE TNGT AND THAT WOULD LIMIT SFC HTG. CONSIDERING THE MARGINAL LAPSE RATES AND MID LVL DRY AIR EXHIBITED IN GFS/NAM FCST SDNGS IN THE ABSENCE OF DYNAMIC FORCING...BELIEVE REDVLPMNT OF DIURNAL SHRA IN THE AFTN IS A LO POTENTIAL. SO ELECTED TO CUT GOING GENERAL 30 POP TO NO MORE THAN 20. .LONG TERM (SATURDAY NIGHT THROUGH FRIDAY)... THIS PERIOD REMAINS PLAGUED BY WEAK SHORTWAVES...MAKING SPECIFIC TIMING OF CLOUDS AND PRECIPITATION DIFFICULT. FOR THE LONG TERM THIS RESULTS IN AVERAGE FORECASTER CONFIDENCE IN THE SPECIFICS. LINGERING PRECIPITATION WILL START OFF THIS PERIOD THANKS TO A WEAK SHORTWAVE MOVING THROUGH THE CWA. A SLIGHTLY STRONGER SYSTEM IS FIGURED FOR SUNDAY AND SUNDAY NIGHT...MOVING THROUGH THE UPPER GREAT LAKES. THE POTENTIAL REMAINS FOR THUNDERSTORM ACTIVITY...ALBEIT ISOLATED. A COLD FRONT WILL BE POISED TO MOVE WEST TO EAST OVER UPPER MICHIGAN LATE SUNDAY AFTERNOON THROUGH THE EARLY OVERNIGHT HOURS. THE ENTIRE SYSTEM IS THEN EXPECTED TO STRENTHEN OVER SOUTHEASTERN ONTARIO AND LAKE HURON MONDAY MORNING. THIS SHOULD KEEP NORTH TO NORTHWESTERLY WINDS AND A BETTER CHANCE OF LINGERING CLOUDS ACROSS EASTERN UPPER MICHIGAN INTO AT LEAST MONDAY AFTERNOON. DRY WEATHER CAN THEN BE EXPECTED FOR THE MIDDLE OF THE UPCOMING WORK WEEK...AS HIGH PRESSURE MOVES IN AT THE SURFACE AND A ZONAL FLOW SETS UP AT 500MB. HPC GUIDANCE WAS FOLLOWED PRETTY CLOSELY FOR THIS PERIOD...EXCLUDING SKY COVER WHICH NEEDED TO BE MINIMIZED A LITTLE MORE INITIALLY. THIS WAS HEAVILY BASED ON ENSEMBLES...WITH A LEAN TOWARDS THE 12Z GFS. FOR THE LATTER HALF OF THE WORK WEEK THOUGH...SOUTHWESTERLY FLOW WILL RETURN BRINGING A BETTER CHANCE OF SHOWERS OR THUNDERSTORMS THURSDAY AND FRIDAY. && .AVIATION (FOR THE 00Z TAF ISSUANCE)... EXPECT VFR CONDITIONS TO PREVAIL AT KCMX/KSAW THRU THE EVENING HRS INTO MUCH OF THE OVERNIGHT PERIOD. SCT -SHRA WL ARRIVE LATER IN THE NIGHT AS LOW PRES MOVES FROM MN TO WRN LAKE SUPERIOR. ALTHOUGH VFR CONDITIONS ARE LIKELY WHEN THE PCPN ARRIVES...MVFR CONDITIONS WITH LOW CLOUD/FOG SHOULD DEVELOP AS PCPN ENDS WITH ARRIVAL OF DRIER AIR ALOFT ABOVE THE LOW-LEVELS MOISTENED BY THE PCPN AND DIURNAL COOLING. THERE WILL BE SLOW IMPROVEMENT SAT MORNING...BUT VFR CONDITIONS WILL DEVELOP IN THE AFTN. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... LOW PRESSURE OVER FAR WESTERN QUEBEC WILL WEAKEN AS IT MOVES OVER NEW BRUNSWICK SATURDAY MORNING WHILE A HIGH PRESSURE RIDGE OVER WESTERN LAKE SUPERIOR THIS EVENING MOVES OVER THE EASTERN GREAT LAKES ON SUNDAY. MEANWHILE...A TROUGH OF LOW PRESSURE WILL CROSS LAKE SUPERIOR SATURDAY. ANOTHER DEEPER LOW PRESSURE TROUGH WILL FOLLOW LATE SUNDAY INTO MONDAY...WITH HIGH PRESSURE BUILDING OVER THE LOWER GREAT LAKES MONDAY. THIS HIGH WILL SHIFT INTO THE EASTERN GREAT LAKES ON WEDNESDAY. WINDS THROUGH THE WEEKEND WILL BE NO HIGHER THAN 20 KNOTS. THE NEXT CHANCE FOR STRONGER WINDS WILL BE ON MONDAY. NORTHWEST WINDS THEN ARE LIKELY TO REACH 25 KNOTS... ESPECIALLY OVER THE EAST HALF...AS HIGH PRESSURE FOLLOWS THE TROUGH INTO THE UPPER GREAT LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN...NONE. LAKE SUPERIOR...NONE. LAKE MICHIGAN...NONE. && $$ SYNOPSIS/SHORT TERM...KC LONG TERM...KF AVIATION...ROLFSON MARINE...KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 730 PM EDT FRI SEP 5 2008 LATEST UPDATE...AVIATION... .SYNOPSIS...(400 PM EDT FRI SEP 5 2008) AN UPPER LEVEL TROUGH OF LOW PRESSURE COVERING THE MID SECTION OF THE NATION WILL RESULT IN A SOMEWHAT UNSETTLED WEATHER PATTERN THROUGH EARLY NEXT WEEK. DISTURBANCES PASSING THROUGH THIS UPPER TROUGH WILL LEAD TO PERIODIC EPISODES OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS. HOWEVER PRECIPITATION AMOUNTS WILL BE MOSTLY UNDER ONE HALF INCH AND SCATTERED IN NATURE. && .SHORT TERM...(400 PM EDT FRI SEP 5 2008) (TONIGHT THROUGH SUNDAY NIGHT) MUCH OF THE CLOUDINESS LINGERING AROUND THE AREA THIS AFTERNOON APPEARS DIURNALLY DRIVEN AND SHOULD TEND TO DECREASE AFTER SUNSET. WINDS WILL ALSO BE DIMINISHING WITH WEAK HIGH PRESSURE BUILDING IN... WHICH COULD SET THE STAGE FOR SOME FOG FORMATION ESPECIALLY CONSIDERING ALL THE RAIN WHICH HAS RECENTLY FALLEN. NOT SURE JUST HOW WIDESPREAD OR DENSE THE FOG MAY GET... BUT WILL INCLUDE PATCHY FOG IN THE GRIDS AFTER 06Z. SHORTWAVE DISTURBANCE CURRENTLY SEEN OVER THE CENTRAL AND SRN PLAINS IN BASE OF BROAD LONGWAVE TROUGH WILL HEAD TO THE NORTHEAST TONIGHT AND SATURDAY. HAVE MAINTAINED POPS FOR SHOWERS ON SATURDAY IN NRN PORTIONS OF THE CWFA TO ACCOUNT FOR THE TRACK/EXTRAPOLATION OF THIS FEATURE. THE H5 VORT PATTERN SHOWN BY THE MODELS WITHIN THE LONGWAVE TROUGH IS VERY NOISY AND THE TIMING/LOCATION OF SUBSEQUENT SHORTWAVES TO IMPACT THE REGION AFTER SATURDAY IS VERY DIFFICULT. FOR THAT REASON WILL CARRY POPS IN EACH PERIOD. POPS SHOULD INCREASE WITH TIME HOWEVER AS THE ENTIRE LONGWAVE TROUGH MIGRATES SLOWLY EAST AND A FRONTAL BOUNDARY APPROACHES FROM THE WEST. THIS FRONT LOOKS TO SLOW/STALL SUNDAY NIGHT FROM SRN LWR MI TO THE SRN PLAINS. && .LONG TERM...(400 PM EDT FRI SEP 5 2008) (MONDAY THROUGH FRIDAY) THE ACTIVE WEATHER PATTERN WILL CONTINUE THROUGH THE EXTENDED PERIOD. WE/LL SEE THE POSSIBILITY OF RAIN MONDAY AND ESPECIALLY MONDAY NIGHT WHEN A LOW IS PROGD TO RIDE ALONG A FRONTAL BOUNDARY TO THE SOUTH AND MOVE ACROSS NRN INDIANA. ALONG WITH THE SFC WAVE THERE IS ALSO A SHARP UPPER TROUGH TO HELP IN PCPN PRODUCTION. DUE TO WEAK INSTABILITY...MORE SHRA THAN TSRA ARE EXPECTED. DRY WX RETURNS TUE AND WED NIGHT BEFORE A WARM FRONT TRIES TO COME BACK NORTH THURSDAY AHEAD OF ANOTHER APPROACHING COLD FRONT THAT IS CURRENTLY PROGD TO MOVE THROUGH FRIDAY. WE/LL HAVE TSRA IN THE GRIDS TO ACCOUNT FOR BOTH OF THE FRONTS. TEMPS WILL REMAIN NEAR NORMAL WITH HIGHS AROUND 70 AND LOWS IN THE 40S AND 50S. && .MARINE...(630 PM EDT FRI SEP 5 2008) BUOY #45007 IN SRN LAKE MI SHOWS A STEADY DOWNWARD TREND IN WAVES WITH HEIGHTS NOW BELOW 4 FEET. LOCAL WEBCAMS SHOWING MUCH QUIETER CONDITIONS ALONG THE LAKESHORE...TOO. HAVE THEREFORE LET THE SMALL CRAFT ADVISORY EXPIRE AS SCHEDULED AT 6 PM EDT...AND SENT OUT AN UPDATED NEARSHORE FORECAST TO REFLECT THIS. && .AVIATION...(730 PM EDT FRI SEP 5 2008) WENT WITH VFR CONDITIONS FOR ALL AREAS...EXCEPT FOR JXN...WHICH SHOULD SHOULD LOSE ITS MVFR CIGS BEFORE 02Z. SATELLITE AND RADAR SHOW AN UPPER DISTURBANCE AND ASSOCIATED AREA OF SHOWERS AND THUNDERSTORMS NEAR THE IA/WI/MN BORDER MOVING NE. THIS FEATURE WILL CONTINUE TO SHEAR TO THE NE. RECENT TRENDS INDICATE A DECREASE IN PRECIPITATION INTENSITY...LIKELY DUE IN PART TO THE LOSS OF DAYTIME HEATING. BASED ON SATELLITE AND RUC MODEL PROGS...WE DO EXPECT SOME LEFTOVER LOW/MID CLOUDINESS TO SPREAD INTO THE AREA AROUND 05Z WITH THIS FEATURE. HOWEVER...WE DID NOT MENTION THIS IN THE TAFS BECAUSE WE BELIEVE CIGS WILL STAY IN VFR RANGE JUST ABOVE 3000 FT. LOW CLOUDS WOULD GREATLY REDUCE THE FOG THREAT MENTIONED ELSEWHERE IN THIS DISCUSSION. THE MOST PROBABLY NEED FOR AMENDMENTS LATER TONIGHT WOULD BE TO INTRODUCE MVFR CIGS...BUT WE ARE NOT YET CONFIDENT ENOUGH TO DO THIS. && .HYDROLOGY...(400 PM EDT FRI SEP 5 2008) MAX RAINFALL FROM GUSTAV WAS 3-5 INCHES ALONG THE LAKESHORE BETWEEN SOUTH HAVEN AND WHITEHALL... EAST NORTHEAST FROM THERE ACROSS GRAND RAPIDS AND NEWAYGO AND INTO BIG RAPIDS AND GREENVILLE. AMOUNTS TAPERED OFF RAPIDLY SOUTHEAST OF A LINE FROM BATTLE CREEK TO ALMA WHERE LESS THAN ONE INCH WAS REPORTED. THERE HAVE BEEN A FEW REPORTS OF STANDING WATER IN YARDS AND A FEW SMALLER CREEKS AND STREAMS OUT OF THEIR BANKS... BUT IN GENERAL NO SERIOUS FLOODING HAS BEEN REPORTED DUE TO THE EXTREMELY DRY CONDITIONS PRECEDING THIS EVENT. NONE OF THE RIVER FCST POINTS ARE FCST TO REACH FLOOD STAGE OVER THE NEXT FEW DAYS. RAINFALL AMOUNTS OVER THE WEEKEND ARE EXPECTED TO BE MOSTLY BELOW ONE HALF INCH AND SCATTERED IN NATURE. THIS SHOULD HAVE LITTLE OR NO IMPACT ON THE CURRENT HYDRO SITUATION. ANY HIGHER AMOUNTS WOULD LIKELY BE VERY ISOLATED. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ SYNOPSIS: MEADE SHORT TERM: MEADE LONG TERM: 93 MARINE: TJT AVIATION: TJT HYDROLOGY: MEADE mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 703 PM EDT FRI SEP 5 2008 .AVIATION... WEAK LOW LEVEL DRY AIR ADVECTION FROM THE NORTHWEST HAS BEEN ALLOWING A DIMINISHING TREND TO THE STRATO CU FIELD. BASES HAVE ALSO RISEN TO VFR. THE LOW LEVEL MOISTURE PROFILE ON THE LATEST DTW TAMDAR SOUNDING LENDS MORE SUPPORT TO RUC MODEL SOUNDINGS...WHICH SHOW A LITTLE GREATER DEPTH TO THE LOW LEVEL MOISTURE. WOULD THEREFORE EXPECT SOME REDEVELOPMENT OF A VFR STRATO CU FIELD UNDERNEATH DEVELOPING SUBSIDENCE INVERSION TONIGHT. THE INSTABILITY PROFILE OVER LAKE HURON IS ALSO SUPPORTIVE OF LAKE STRATUS TONIGHT. NORTHERLY FLOW WILL ADVECT THIS STRATUS INLAND...LIKELY IMPACTING FNT AND DTW WITH MVFR CIGS AFTER 09Z. MEANWHILE...NORTH-NORTHWESTERLY DOWNSLOPE FLOW SHOULD MAINTAIN A SCT DECK AT MBS. THE ONSET OF DAYTIME HEATING WILL ALLOW CLOUDS TO SCATTER OUT BY 15Z SUN. && .PREV DISCUSSION...ISSUED 401 PM EDT FRI SEP 5 2008 SHORT TERM...TONIGHT LOW PRESSURE THAT BROUGHT A COLD FRONT THROUGH THE AREA EARLY THIS MORNING WILL CONTINUE TO TRACK NORTHEAST ACROSS QUEBEC TONIGHT. A FEW SPRINKLES ARE SHOWING UP ON AREA RADARS OUT OF THE DENSE STRATOCU DECK THAT REMAINS OVER SOUTHEAST MICHIGAN. THIS DECK IS CLEARING FROM THE NORTHWEST WITH NORTHERN PORTIONS OF THE CWA EXPECTED TO SEE MOSTLY CLEAR SKIES DEVELOP LATE THIS EVENING. MEANWHILE A LINGERING THERMAL TROUGH EXTENDING BACK FROM THE SURFACE LOW ACROSS LAKE HURON AND LAKE ERIE WILL HELP THE CLOUDS PERSIST THROUGH THE NIGHT IN OUR SOUTHERN AND EASTERN COUNTIES. DESPITE AN OVERALL DRYING TREND IN DEWPOINTS...NORTHERLY WINDS OFF LAKE HURON WILL CONTINUE TO ADD MOISTURE TO THE BOUNDARY LAYER MAKING PATCHY FOG A CONCERN FOR AREAS NEAR THE LAKES TONIGHT. GUIDANCE NUMBERS LOOKED REASONABLE IN THE NORTH WHERE SKIES SHOULD BE MOSTLY CLEAR BUT HAVE GONE A FEW DEGREES ABOVE GUIDANCE IN THE SOUTH WHERE CLOUDS SHOULD HANG ON OVERNIGHT. LONG TERM...SATURDAY THROUGH NEXT FRIDAY UPPER SHORTWAVE SPINNING OVER KS/NE WILL LIFT NORTHEAST AND ACROSS LOWER MICHIGAN EARLY TOMORROW...JUST AHEAD OF AN APPROACHING WEAK SURFACE TROUGH THAT IS CURRENTLY PUSHING INTO NORTHERN MINNESOTA. THIS TROUGH WILL THEN LIFT ACROSS NORTHERN LAKE HURON TOMORROW EVENING. WATER VAPOR IMAGERY INDICATES THIS SHORTWAVE MAY BE A LITTLE STRONGER THAN MODELS SUGGEST. WITH MODELS STREAMING SOME MOISTURE IN AHEAD OF THESE FEATURE TOMORROW...AND GUIDANCE EVEN KICKING OUT SOME POPS...WILL ADD A MENTION OF SHOWERS UP AROUND THE TRI-CITIES FOR TOMORROW AFTERNOON. OTHERWISE...JUST EXPECT INCREASING CLOUDS FOR THE REMAINDER OF SOUTHEAST MICHIGAN TOWARDS AFTERNOON AND EVENING AS THESE FEATURES PASS TO OUR NORTH. TEMPERATURES ARE EXPECTED TO REBOUND BACK UP INTO THE 70S TOMORROW. BROAD UPPER TROUGHING WILL SET UP ACROSS MUCH OF THE NORTHERN U.S. SATURDAY NIGHT...USHERING IN A PERIOD OF FAST ENERGETIC WESTERLY FLOW THAT WILL HOLD OVER THE GREAT LAKES INTO TUESDAY. INDIVIDUAL WAVES THAT WILL EJECT THROUGH THIS FLOW WILL BE HARD TO TIME...BUT LARGER WAVES ARE STILL EXPECTED TO PUSH THROUGH ON SUNDAY AND MONDAY. NAM/GFS IN GOOD AGREEMENT WITH A WEAK WARM FRONT LIFTING UP THROUGH SOUTHERN LOWER MICHIGAN SUNDAY MORNING...AND INTO CENTRAL LOWER MICHIGAN BY LATE AFTERNOON. NAM SHOWS GREAT MOIST ISENTROPIC ASCENT OCCURING EARLY OVER THE SOUTHERN PORTION OF THE FORECAST AREA...THEN LIFTING SLOWLY NORTHWARD THROUGHOUT THE DAY. GFS DIFFERS SLIGHTLY AND KEEPS STRONGER ASCENT LIMITED TO THE TRI-CITIES AND THUMB. WILL HOLD ONTO CHANCE POPS THROUGHOUT THE DAY...WITH THE EXPECTATION OF SEEING MORE ACTIVITY ALONG AND NORTH OF I-69...AT LEAST UNTIL MODELS COME INTO BETTER AGREEMENT. PRECIPITATION SHOULD BE FAIRLY LIGHT. BETTER CHANCE OF PRECIPITATION WILL OCCUR LATE SUNDAY NIGHT AND MONDAY AS THE STRONGEST OF THE UPPER WAVES MOVES THROUGH MICHIGAN AND PUSHES A COLD FRONT THROUGH THE REGION. COLDER AIR WILL CONTINUE TO SPILL INTO THE REGION ON TUESDAY AS THE FRONT EXITS AND A COOL DOME OF HIGH PRESSURE SETTLES IN OVERHEAD. CONDITIONS WILL TURN QUITE FALL-LIKE ON TUESDAY AS H850 TEMPS COOL TO AROUND 5 DEGREES C. THIS SHOULD PROVIDE SURFACE TEMPERATURES THAT STRUGGLE TO REACH EVEN THE UPPER 60S...WITH OVERNIGHT LOWS THEN DROPPING INTO THE 40S JUST ABOUT EVERYWHERE. SOME CONCERN FOR STRATUS DEVELOPMENT TUESDAY BEHIND THE FRONT AS COOL AIR STREAMS OVER THE VERY WARM LAKES. THE ADDITIONAL CLOUD COVER WOULD HAVE AN EFFECT ON TEMPERATURES...AND FORECAST WILL NEED TO BE AJUSTED IF THIS SCENARIO STARTS TO LOOK MORE FAVORABLE HIGH PRESSURE STILL EXPECTED TO HOLD OVER THE REGION INTO WEDNESDAY BEFORE SOUTHERLY FLOW STARTS TO INCREASE AHEAD OF THE NEXT UPPER TROUGH. MEDIUM RANGE MODELS ARE STARTING TO STRUGGLE WITH HOW THEY HANDLE MID-WEEK UPSTREAM ENERGY OVER THE PACIFIC NORTHWEST. HAVE A HIGH DEGREE OF CONFIDENCE WITH THE TROUGH ARRIVING TOWARDS THE END OF THE WEEK...BUT LOW CONFIDENCE WITH DETAILS...AMPLITUDE...AND EXACT TIMING. MARINE... THE PRESSURE GRADIENT WILL CONTINUE TO WEAKEN INTO SATURDAY AS THE LOW PRESSURE SYSTEM THAT MOVED THROUGH THE AREA LAST NIGHT CONTINUES NORTHEAST ACROSS QUEBEC. SUSTAINED WINDS WILL REMAIN AROUND 20 KNOTS ACROSS NORTHERN LAKE HURON WHILE OTHER AREAS HAVE ALREADY STARTED TO SUBSIDE. SMALL CRAFT ADVISORIES HAVE BEEN EXTENDED OVERNIGHT FOR THE OUTER SAGINAW BAY AND INTO SATURDAY ON NEARSHORE AREAS FROM PORT AUSTIN TO PORT SANILAC AS WAVES WILL REMAIN HIGH UNDER NORTHERLY WINDS. CONDITIONS WILL BECOME MORE FAVORABLE FOR BOATING FROM SATURDAY AFTERNOON INTO SUNDAY AS HIGH PRESSURE BUILDS EASTWARD ACROSS THE GREAT LAKES REGION. ANOTHER LOW PRESSURE SYSTEM WILL BRING THE NEXT COLD FRONT THROUGH THE REGION ON MONDAY...POTENTIALLY CREATING MORE UNSTABLE CONDITIONS AS MUCH COOLER AIR FILTERS ACROSS THE WARMER LAKE WATERS. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... SMALL CRAFT ADVISORY...OUTER SAGINAW BAY...UNTIL 4 AM SATURDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO HARBOR BEACH...UNTIL 10 AM SATURDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM HARBOR BEACH TO PORT SANILAC...UNTIL 4 PM SATURDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....SC SHORT TERM...KEC LONG TERM....HLO MARINE.......KEC 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 325 PM EDT FRI SEP 5 2008 .SYNOPSIS... 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR TROFFING CENTERED OVER CNTRL NAMERICA BTWN RDGS ON THE E AND W COASTS. SHRTWV/DEEP MSTR ASSOCIATED WITH THE REMNANTS OF GUSTAV ARE MOVING RDPLY NE THRU SE CAN...BUT A SUBTLE LO PRES TROF REMAINS OVER THE FA ON ITS WRN FLANK. RECENT TAMDAR SDNGS SHOW A GOOD AMT OF LLVL MSTR REMAINS OVER THE UPR GRT LKS UNDER THE SUBSIDENCE INVRN ARND H75 LEFT IN ITS WAKE. SO QUITE A BIT OF SC IS PRESENT DESPITE DIURNAL HTG THAT HAS LIFTED CLD BASE AND ENDED ANY -DZ THAT WAS OBSVD EARLIER. THE COMBINATION OF SOME SUBSIDENCE OVER LK SUP RELATED TO THE LK BREEZE CIRCULATION AND THE ARRIVAL OF SOMEWHAT DRIER AIR FM THE NW THAT WAS SHOWN BEST ON THE 00Z RAOBS FM INL/YPL HAS TENDED TO BREAK UP THE CLD MORE AGGRESSIVELY THERE AND NEAR THE LK SHORES. NEXT SHRTWV OF CONCERN IS PRESENTLY MOVING ACRS NRN MN ALONG WITH AN ASSOCIATED SFC LO. THERE IS QUITE A BIT OF CLD TO THE N AND W OF THIS LO...AND THE ERN EDGE OF THE THICKER CLD IS MOVING TOWARD WRN LK SUP. SOME SCT -SHRA ARE AS FAR E AS DLH IN AXIS OF HIER SPECIFIC HUMIDITY SHOWN ON THE 300K ISENTROPIC SFC (ARND H7) BY THE 12Z NAM F6. BUT OVERALL PCPN COVG SEEMS LIMITED BY THE DRY MID LVLS SHOWN ON THE 12Z MPX RAOB. && .SHORT TERM DISCUSSION (TNGT AND SAT)... FOR TNGT...12Z GFS/NAM SHOW SHRTWV NOW OVER NRN MN SHEARING ENEWD AND WEAKENING A BIT TO NEAR ISLE ROYALE BY 12Z SAT AS UPR TROF AXIS REMAINS SITUATED IN THE PLAINS. THE ACCOMPANYING SFC LO IS PROGGED TO REACH THE WRN SHORE OF THE U.P. BOTH MODELS SHOW AXIS OF HIEST SPECIFIC HUMIDITY NOW OVER MN AND ON THE 300K SFC SHIFTING INTO THE W THIS EVNG THEN THE ECNTRL BY 12Z SAT WITH ISENTROPIC LIFT NOTED ON THE 295-305K SFCS/QVECTOR CNVGC IN THE H85-5 LYR. GFS IS A BIT MORE GENEROUS WITH QPF...BUT PREFER THE SOMEWHAT MORE MODEST NAM GIVEN THE MID LVL DRY AIR SHOWN ON THE 12Z MPX RAOB THAT IS LIMITING PCPN COVG NOW. STILL...HAVE OPTED TO BUMP POPS UP TO 40 BEFORE FAIRLY AGGRESSIVE DRYING ON THE 300K SFC IN THE JET SURGE REGION ON THE SE FLANK OF THE SHRTWV TRACK OVERSPRDS THE FA. GOING FCST MIN TEMPS ARE FAIRLY IN LINE WITH LATEST GFS/ETA/NGM MOS GUIDANCE...SO NO SGNFT CHGS MADE TO GOING FCST. ON SAT...THE DEEPER MSTR ALF WL IMPACT THE ERN ZNS IN THE MRNG BEFORE THE DRYING ON THE 300K SFC IS FCST TO CLR ERY BY 18Z OR SO AS THE SHRTWV NR ISLE ROYALE/SFC LO OVER WRN LK SUP AT 12Z SHIFTS NE INTO ONTARIO. TO THE W...THE FOCUS SHIFTS TO WHETHER ENUF LLVL MSTR WL LINGER TO ALLOW THE REDVLPMNT OF MORE SHRA WITH DIURNAL HTG. IF THE TIME OF YEAR WERE CLOSER TO THE SUMMER SOLSTICE...THAT WOULD BE A REAL CONCERN. OTHER CONSIDERATIONS INCLUDE THE PRESENCE OF LINGERING LO CLD IN THE MRNG WHICH DVLPS WITH THE ARRIVAL OF THE DRYING ALF LATE TNGT AND THAT WOULD LIMIT SFC HTG. CONSIDERING THE MARGINAL LAPSE RATES AND MID LVL DRY AIR EXHIBITED IN GFS/NAM FCST SDNGS IN THE ABSENCE OF DYNAMIC FORCING...BELIEVE REDVLPMNT OF DIURNAL SHRA IN THE AFTN IS A LO POTENTIAL. SO ELECTED TO CUT GOING GENERAL 30 POP TO NO MORE THAN 20. && .LONG TERM (SATURDAY NIGHT THROUGH FRIDAY)... THIS PERIOD REMAINS PLAGUED BY WEAK SHORTWAVES...MAKING SPECIFIC TIMING OF CLOUDS AND PRECIPITATION DIFFICULT. FOR THE LONG TERM THIS RESULTS IN AVERAGE FORECASTER CONFIDENCE IN THE SPECIFICS. LINGERING PRECIPITATION WILL START OFF THIS PERIOD THANKS TO A WEAK SHORTWAVE MOVING THROUGH THE CWA. A SLIGHTLY STRONGER SYSTEM IS FIGURED FOR SUNDAY AND SUNDAY NIGHT...MOVING THROUGH THE UPPER GREAT LAKES. THE POTENTIAL REMAINS FOR THUNDERSTORM ACTIVITY...ALBEIT ISOLATED. A COLD FRONT WILL BE POISED TO MOVE WEST TO EAST OVER UPPER MICHIGAN LATE SUNDAY AFTERNOON THROUGH THE EARLY OVERNIGHT HOURS. THE ENTIRE SYSTEM IS THEN EXPECTED TO STRENTHEN OVER SOUTHEASTERN ONTARIO AND LAKE HURON MONDAY MORNING. THIS SHOULD KEEP NORTH TO NORTHWESTERLY WINDS AND A BETTER CHANCE OF LINGERING CLOUDS ACROSS EASTERN UPPER MICHIGAN INTO AT LEAST MONDAY AFTERNOON. DRY WEATHER CAN THEN BE EXPECTED FOR THE MIDDLE OF THE UPCOMING WORK WEEK...AS HIGH PRESSURE MOVES IN AT THE SURFACE AND A ZONAL FLOW SETS UP AT 500MB. HPC GUIDANCE WAS FOLLOWED PRETTY CLOSELY FOR THIS PERIOD...EXCLUDING SKY COVER WHICH NEEDED TO BE MINIMIZED A LITTLE MORE INITIALLY. THIS WAS HEAVILY BASED ON ENSEMBLES...WITH A LEAN TOWARDS THE 12Z GFS. FOR THE LATTER HALF OF THE WORK WEEK THOUGH...SOUTHWESTERLY FLOW WILL RETURN BRINGING A BETTER CHANCE OF SHOWERS OR THUNDERSTORMS THURSDAY AND FRIDAY. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... EXPECT VFR CONDITIONS TO PREVAIL INTO TNGT WITH WEAK HI PRES RDG DOMINATING. SOME SHRA WL ARRIVE LATER TNGT AS A LOW PRES MOVES FM MN INTO WRN LK SUP. ALTHOUGH VFR CONDITIONS ARE LIKELY WHEN THE RA ARRIVES...MVFR CONDITIONS WITH LO CLD/FOG WL DVLP TOWARD WHEN THE RA ENDS WITH THE ARRIVAL OF DRIER AIR ALF ABV THE LLVLS MOISTENED BY THE PCPN AND DIURNAL COOLING. THERE WL BE ONLY GRADUAL IMPROVEMENT ON SAT MRNG. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... LOW PRESSURE OVER FAR WESTERN QUEBEC WILL WEAKEN AS IT MOVES OVER NEW BRUNSWICK SATURDAY MORNING WHILE A HIGH PRESSURE RIDGE OVER WESTERN LAKE SUPERIOR THIS EVENING MOVES OVER THE EASTERN GREAT LAKES ON SUNDAY. MEANWHILE...A TROUGH OF LOW PRESSURE WILL CROSS LAKE SUPERIOR SATURDAY. ANOTHER DEEPER LOW PRESSURE TROUGH WILL FOLLOW LATE SUNDAY INTO MONDAY...WITH HIGH PRESSURE BUILDING OVER THE LOWER GREAT LAKES MONDAY. THIS HIGH WILL SHIFT INTO THE EASTERN GREAT LAKES ON WEDNESDAY. WINDS THROUGH THE WEEKEND WILL BE NO HIGHER THAN 20 KNOTS. THE NEXT CHANCE FOR STRONGER WINDS WILL BE ON MONDAY. NORTHWEST WINDS THEN ARE LIKELY TO REACH 25 KNOTS... ESPECIALLY OVER THE EAST HALF...AS HIGH PRESSURE FOLLOWS THE TROUGH INTO THE UPPER GREAT LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN...NONE. LAKE SUPERIOR...NONE. LAKE MICHIGAN...NONE. && $$ SYNOPSIS/SHORT TERM...KC LONG TERM...KF AVIATION...KC MARINE...KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 1049 AM CDT SAT SEP 6 2008 .UPDATE...INCREASED POPS AND INTRODUCED THUNDER FOR THIS AFTERNOON WITH MORNING UPDATE. WEAK SURFACE TROFPA AND UPPER VORT MAX...ALONG WITH LIMITED DAYTIME INSTABILITY SHOULD RESULT IN SCT COVERAGE OF SHOWERS AND TSTMS THIS AFTERNOON....AND LATEST NAM SHOWS DEVELOPMENT AS WELL. REST OF FORECAST LOOKS ON TRACK ATTM. && .PREV DISCUSSION... /ISSUED 333 AM CDT SAT SEP 6 2008/ DISCUSSION...MAIN FOCUS IS RESOLVING VARIOUS PRECIPITATION THREATS OVER THE NEXT SEVERAL DAYS. A BROAD TROUGH OF LOW PRESSURE WILL CONTINUE TO BE FOUND ACROSS THE CWA OVER THE NEXT FEW DAYS...WITH THE H3 JET WELL SOUTH OF THE AREA INTO THE CENTRAL PLAINS/MID MISSISSIPPI VALLEY. THE RESULT WILL BE LITTLE CHANGE IN DAY TO DAY TEMPS AND UNSETTLED WEATHER AT TIMES. THE PATTERN SHIFTS TO AN UPPER LEVEL RIDGING SCENARIO TOWARD MIDWEEK BUT ANOTHER TROUGH DEVELOPS LATER IN THE WEEK. SCATTERED SHOWERS AND PATCHY FOG WERE FOUND ACROSS THE CWA THIS MORNING...MOST OF THE SHOWER ACTIVITY WAS QUITE LIGHT AND ACROSS THE NORTHERN HALF OF THE CWA. THE LATEST RUC PICKS UP NICELY ON THE VORT MAXES MOVING ACROSS NORTHERN MINNESOTA WITH WEAK SURFACE LOW PRESSURE AS WELL. THE SHORTWAVES ARE EXPECTED TO GRADUALLY MOVE EAST OF THE REGION TODAY...BUT MAY TAKE SOME TIME AS THEY ROTATE THROUGH THE REGION. A COLD FRONT IS THEN POISED TO PUSH INTO NORTH CENTRAL MINNESOTA BY LATE AFTERNOON/EARLY EVENING WITH SOME ADDITIONAL SHOWER ACTIVITY DEVELOPING AHEAD OF THIS SYSTEM. WILL KEEP SCATTERED SHOWERS IN THE FORECAST FOR THE NORTHERN 2/3 OF THE CWA...WITH ISOLATED IN THE SOUTH. STILL COULD NOT RULE OUT A STRAY THUNDERSTORM...BUT WILL KEEP IT SHOWERS AT THIS POINT. A DECENT SHORTWAVE DIGS INTO NORTHERN MINNESOTA LATER TONIGHT AND SUNDAY...WITH THE COLD FRONT SWEEPING FROM WEST TO EAST ACROSS THE AREA. THIS SHORTWAVE SHOULD SET OFF A BETTER CHANCE OF SHOWERS AND PERHAPS A FEW THUNDERSTORMS. MOS GUIDANCE HAS SOME 60 POP NUMBERS FOR SUNDAY...ESPECIALLY IN THE NORTHERN AREAS. WILL MAINTAIN 50 POPS FOR NOW...BUT MAY NEED TO INCREASE TO LIKELY AT SOME POINT. EARLY TO MID WEEK RIDGING SHOULD BRING A PERIOD OF RELATIVE QUIET FROM LATER SUNDAY NIGHT INTO TUESDAY NIGHT. COULD BE A VERY ISOLATED DIURNALLY DRIVEN SHOWER IN BETWEEN...BUT WILL LEAVE OUT FOR NOW. THE NEXT SYSTEM SHOULD ARRIVE AT SOME POINT ON WEDNESDAY AND CONTINUE TO AFFECT THE AREA INTO THURSDAY NIGHT. GFS/ECMWF IN OK AGREEMENT AT THIS POINT...AND MAY NEED TO KEEP INCREASING POPS AS THE EVENT APPROACHES. COULD BE SOME DECENT RAIN. TEMPS OVER MUCH OF THE PERIOD SHOULD CHANGE VERY LITTLE...WITH HIGHS MAINLY IN THE 60S...AND LOWS MAINLY IN THE 30S AND 40S WITH LITTLE EXCEPTION. AVIATION...SCT TO ISOLD -SHRA AND MVFR CIGS WILL PREVAIL...WITH SCT IFR CIGS AND FG THROUGH THE EARLY MORNING. AFT 14Z...CEILINGS AND VSBYS WILL LIFT TO VFR ACROSS THE FA. THE SHRA ACTIVITY IS EXPECTED TO SUBSIDE THROUGH THE MORNING...THEN REDEVELOP THIS AFTERNOON....MAINLY AFT 20Z WITH THE GREATEST COVERAGE IN THE NRN HALF OF THE FA. && POINT TEMPS/POPS... DLH 64 44 60 42 / 30 30 50 20 INL 62 41 58 39 / 40 40 50 10 BRD 70 46 61 44 / 20 30 50 10 HYR 69 44 62 43 / 30 20 50 40 ASX 65 46 62 44 / 30 20 50 30 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. $$ LILES mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 333 AM CDT SAT SEP 6 2008 .DISCUSSION...MAIN FOCUS IS RESOLVING VARIOUS PRECIPITATION THREATS OVER THE NEXT SEVERAL DAYS. A BROAD TROUGH OF LOW PRESSURE WILL CONTINUE TO BE FOUND ACROSS THE CWA OVER THE NEXT FEW DAYS...WITH THE H3 JET WELL SOUTH OF THE AREA INTO THE CENTRAL PLAINS/MID MISSISSIPPI VALLEY. THE RESULT WILL BE LITTLE CHANGE IN DAY TO DAY TEMPS AND UNSETTLED WEATHER AT TIMES. THE PATTERN SHIFTS TO AN UPPER LEVEL RIDGING SCENARIO TOWARD MIDWEEK BUT ANOTHER TROUGH DEVELOPS LATER IN THE WEEK. SCATTERED SHOWERS AND PATCHY FOG WERE FOUND ACROSS THE CWA THIS MORNING...MOST OF THE SHOWER ACTIVITY WAS QUITE LIGHT AND ACROSS THE NORTHERN HALF OF THE CWA. THE LATEST RUC PICKS UP NICELY ON THE VORT MAXES MOVING ACROSS NORTHERN MINNESOTA WITH WEAK SURFACE LOW PRESSURE AS WELL. THE SHORTWAVES ARE EXPECTED TO GRADUALLY MOVE EAST OF THE REGION TODAY...BUT MAY TAKE SOME TIME AS THEY ROTATE THROUGH THE REGION. A COLD FRONT IS THEN POISED TO PUSH INTO NORTH CENTRAL MINNESOTA BY LATE AFTERNOON/EARLY EVENING WITH SOME ADDITIONAL SHOWER ACTIVITY DEVELOPING AHEAD OF THIS SYSTEM. WILL KEEP SCATTERED SHOWERS IN THE FORECAST FOR THE NORTHERN 2/3 OF THE CWA...WITH ISOLATED IN THE SOUTH. STILL COULD NOT RULE OUT A STRAY THUNDERSTORM...BUT WILL KEEP IT SHOWERS AT THIS POINT. A DECENT SHORTWAVE DIGS INTO NORTHERN MINNESOTA LATER TONIGHT AND SUNDAY...WITH THE COLD FRONT SWEEPING FROM WEST TO EAST ACROSS THE AREA. THIS SHORTWAVE SHOULD SET OFF A BETTER CHANCE OF SHOWERS AND PERHAPS A FEW THUNDERSTORMS. MOS GUIDANCE HAS SOME 60 POP NUMBERS FOR SUNDAY...ESPECIALLY IN THE NORTHERN AREAS. WILL MAINTAIN 50 POPS FOR NOW...BUT MAY NEED TO INCREASE TO LIKELY AT SOME POINT. EARLY TO MID WEEK RIDGING SHOULD BRING A PERIOD OF RELATIVE QUIET FROM LATER SUNDAY NIGHT INTO TUESDAY NIGHT. COULD BE A VERY ISOLATED DIURNALLY DRIVEN SHOWER IN BETWEEN...BUT WILL LEAVE OUT FOR NOW. THE NEXT SYSTEM SHOULD ARRIVE AT SOME POINT ON WEDNESDAY AND CONTINUE TO AFFECT THE AREA INTO THURSDAY NIGHT. GFS/ECMWF IN OK AGREEMENT AT THIS POINT...AND MAY NEED TO KEEP INCREASING POPS AS THE EVENT APPROACHES. COULD BE SOME DECENT RAIN. TEMPS OVER MUCH OF THE PERIOD SHOULD CHANGE VERY LITTLE...WITH HIGHS MAINLY IN THE 60S...AND LOWS MAINLY IN THE 30S AND 40S WITH LITTLE EXCEPTION. && .AVIATION...SCT TO ISOLD -SHRA AND MVFR CIGS WILL PREVAIL...WITH SCT IFR CIGS AND FG THROUGH THE EARLY MORNING. AFT 14Z...CEILINGS AND VSBYS WILL LIFT TO VFR ACROSS THE FA. THE SHRA ACTIVITY IS EXPECTED TO SUBSIDE THROUGH THE MORNING...THEN REDEVELOP THIS AFTERNOON....MAINLY AFT 20Z WITH THE GREATEST COVERAGE IN THE NRN HALF OF THE FA. && POINT TEMPS/POPS... DLH 64 41 58 42 / 20 20 50 20 INL 62 38 57 39 / 30 40 50 10 BRD 69 45 59 44 / 20 30 50 10 HYR 67 43 62 43 / 20 20 50 40 ASX 63 45 62 44 / 20 20 50 30 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. $$ DAP/GRANING mn AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE DULUTH MN 927 PM CDT FRI SEP 5 2008 .UPDATE... STRESSED SHOWERS AND EMPHASIZED A DIURNAL AFTERNOON AND EVENING COMPONENT. DE-EMPHASIZED FOG. MADE WINDS MORE ONSHORE. LOWERED TEMPERATURES A LITTLE. && .DISCUSSION... LOW PRESSURE JUST SOUTH OF DULUTH HAS BECOME MORE WELL DEFINED. THE LOW IS AT THE END OF A NEGATIVELY TILTED SURFACE TROUGH NEAR THE WESTERN EDGE OF OUR FORECAST AREA TO WHERE THE RED RIVER CROSSES THE CANADIAN BORDER BACK TO THE UPPER MANITOBA LAKES. WE ANCPT NORTHEAST WINDS NORTH OF THE TROUGH AS WEAK HIGH PRESSURE DEVELOPES OVER LAKE NIPIGON AND JAMES BAY...NONE OF THE GUIDANCE ANCPTS THIS PRSTG PATTERN. WITH A SERIES OF NEGATIVELY TILTED SHORT WAVES DIGGING DOWN AND THROUGH OUR AREA...THE COLUMN WILL CONTINUE TO COOL ALOFT. WITH THE NEGATIVE TILT AT ALL LEVELS... MOISTURE WILL BE ABLE TO WORK BACK INTO THE STEEPENING LAPSE RATES OVER OUR AREA AND SCATTERED SHOWERS WILL CONTINUE. THE NEXT STRONG SURFACE TROUGH WILL ROTATE THROUGH EARLY SUNDAY AND BE FLWD BY AN UNSEASONABLY CHILLY AND DAMP NORTH FLOW EARLY THE COMING WEEK. && .PREV DISCUSSION... /ISSUED 513 PM CDT FRI SEP 5 2008/ UPDATE... INCREASED POPS ACROSS THE AREA...MENTIONING PRECIPITATION EVERYWHERE AND INTRODUCING ISOLATED THUNDER...AT LEAST THIS EVENING. DISCUSSION... LOW PRESSURE OVER THE UPPER SAINT CROIX VALLEY WITH AN ACTIVE WARM FRONT ALONG THE INLAND COUNTIES OF NORTHWEST WISCONSIN AND A STRENGTHENING TROUGH AND COLD FRONT FROM THE CASS LAKES AREA EASTWARD TO JUST BELOW DULUTH AND SOUTHWARD ALONG THE SAINT CROIX RIVER HAS STIMULATED SMALLISH...SHALLOW BUT POTENT AND LONG LIVED SHOWERS DROPPING HALF AN INCH OF RAIN PER HOUR ACROSS AT LEAST A DOZEN AREAS. WE DO NOT SEE LIGHTNING ATTM...BUT MIGHT SOON. FALLING HEIGHTS AND COOLING ALOFT FASTER THAN AT THE SURFACE AS A DIGGING AND NEGATIVE-TILTED SHORT WAVE DROPS DOWN TO SUPPORT THIS SLOWLY BUT STEADILY DEEPEENING NEGATIVELY-ORIENTED SURFACE LOW IS ALSO BEING ACCOMPANIED BY SIGNIFICANT SPEED DIVERGENCE ALOFT OVER THE STRONGEST SHOWER AREAS. WE ARE STARTING WITH A RADICAL MOISTENING OF TONIGHT/S FORECAST AND WILL BE LOOKING AT OTHER PARAMETERS IN THE NEXT HOUR OR TWO. PREV DISCUSSION... /ISSUED 238 PM CDT FRI SEP 5 2008/ DISCUSSION... SFC LOW NEAR PKD EARLY THIS AFTERNOON WITH ELONGATED SFC TROUGH STRETCHING NORTH TO BDE...AND SOUTH TOWARDS SAZ. MSAS INDICATES A WEAK SECONDARY PRESS FALL CENTER DEVELOPING NEAR RZN. THIS AGREES WELL WITH MDL FCST OF SFC LOW PRESSURE TROUGH ELONGATING SE THIS AFTERNOON. EXTENSIVE CLOUD SHIELD COVERS MOST OF CWA EXCEPT SE WISC WHERE ISENTROPIC ASCENT HAS NOT ARRIVED YET. PRECIP HAS BEEN MINIMAL AS FORCING IS WEAK. LATEST VIS IMAGERY INDICATES INCREASING CONVECTIVE ELEMENTS ENTERING SW CORNER OF CWA. THIS APPEARS TO BE WITHIN A LOW LEVEL THETAE AXIS. 4KM SPC NMM-WRF SIM REFL PRODUCT ACTUALLY DEPICTS THIS CLUSTER AND WORKS IT EAST THIS AFTERNOON TOWARD TWIN PORTS....WEAKENING THE INTENSITY AS IT DOES. A CELL DID PULSE TO 52DBZ AT 11K WITHIN PAST HR NEAR CASS LAKE BUT HAS WEAKENED IN SUBSEQUENT SCANS. LATEST RUC13 SUGGESTS WE NEED 50DBZ CORES TO 16/17K TO GENERATE ANY SIGNIFICANT HAIL. MARGINAL PARAMETERS FOR SIG CONVECTION AS SFC/MUCAPES REMAIN BELOW 1000J/KG...ALTHOUGH 0-6KM SHEAR IS ABOUT 35KTS IN BEST CAPE VICINITY. HAVE LEFT ISO TRW IN FCST THROUGH THIS AFTERNOON BUT NO LIGHTNING HAS BEEN INDICATED WITH ACTIVITY SO FAR. TONIGHT...ELONGATED SFC PRESS TROUGH WILL STRETCH FROM NORTHERN ITASCA TO SAWYER COUNTIES EARLY THIS EVENING. THIS FEATURE WILL CRAWL NORTHEAST OVERNIGHT WITH WEAK CONVERGENCE EXPECTED. PWS RIBBON ASSOCIATED WITH THIS SYSTEM IS NOT THAT IMPRESSIVE SO QPF REMAINS FAIRLY LIGHT. WILL NEED TO ASSESS FOG/BR POTENTIAL BEFORE ZONE ISSUANCE AS POOLING OF MOISTURE NEAR SFC BDRY...COMBINED WITH LIGHT WINDS...MAY PROMOTE LOW VISIBILITIES. TOMORROW...LEANING WITH SREF SCENARIO WITH SUPPORT FROM EC/GFS. THIS KEEPS POPS CONCENTRATED OVER NRN THIRD OF CWA WHERE DEEPER LAYER MOISTURE AND SOME WEAK CONVERGENCE WILL BE PROVIDED BY SFC BDRY. CLOUD FCST WILL BE CHALLENGING AS BREAKS ARE LIKELY PERIODICALLY IN MANY AREAS...ESPECIALLY BY AFTERNOON OVER SRN HALF OF CWA. EXTENDED...A BRIEF LULL SATURDAY EVENING BEFORE NEXT MID LVL DISTURBANCE SWEEPS INTO REGION SUNDAY MORNING.85H TEMPS DROP WITH PASSAGE OF UPPER TROF SO TEMPS WILL COOL SUNDAY/MONDAY/TUES. SLOW MODERATION THEREAFTER ALTHOUGH INCREASING CLOUDS MAY OFFSET ANY WARM ADVECTION ON WEDNESDAY. AVIATION... IFR AND MVFR CONDITIONS HAVE GIVEN WAY TO PREDOMINATELY VFR CONDITIONS ACROSS THE TERMINALS. SCATTERED 15K-25K CLOUDS CAN BE FOUND...WITH A BROKEN TO OVERCAST DECK AT 5K-7K FEET. THERE ARE A FEW POCKETS OF MVFR/IFR IN THE LONGVILLE...TO GRAND RAPIDS...TO BIGFORK AREA...AND OUT TOWARDS BEMIDJI AS OF 20Z. VFR CONDITIONS WILL BE FOUND THROUGH THE REMAINDER OF THE AFTERNOON...WITH OCCASIONAL MVFR CEILINGS GENERALLY AROUND 15K FEET IN RAIN SHOWERS...AS AN UPPER LEVEL DISTURBANCE MOVES EAST THROUGH THE NORTHLAND. CONVECTIVE PARAMETERS ARE WEAK...AND SO HAVE LEFT THE MENTION OF THUNDER OUT...THOUGH THUNDER IS NOT OUT OF THE QUESTION. LOW LEVEL MOISTURE IS EXPECTED TO LINGER INTO THE OVERNIGHT HOURS...PARTICULARLY IN THE NORTH...FROM KINL TO KHIB TO KDLH. HAVE MENTIONED SOME MVFR/IFR STRATUS...WITH SOME FOG AND IFR/LIFR AT KHIB AND KHYR. TOMORROW...COLD UPPER LEVEL TEMPERATURES WILL LEAD TO CUMULUS DEVELOPMENT...WITH THE CHANCE FOR MORE SHOWERS AND ISOLATED THUNDERSTORMS...THOUGH THESE WILL BE AFTER THE 18Z TIME FRAME. && POINT TEMPS/POPS... DLH 45 64 41 58 / 40 20 20 50 INL 41 62 38 57 / 30 30 40 50 BRD 44 69 45 59 / 20 20 30 50 HYR 42 67 43 62 / 20 20 20 50 ASX 45 63 45 62 / 40 20 20 50 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. $$ EOM/TL mn AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE DULUTH MN 513 PM CDT FRI SEP 5 2008 .UPDATE... INCREASED POPS ACROSS THE AREA...MENTIONING PRECIPITATION EVERYWHERE AND INTRODUCING ISOLATED THUNDER...AT LEAST THIS EVENING. && .DISCUSSION... LOW PRESSURE OVER THE UPPER SAINT CROIX VALLEY WITH AN ACTIVE WARM FRONT ALONG THE INLAND COUNTIES OF NORTHWEST WISCONSIN AND A STRENGTHENING TROUGH AND COLD FRONT FROM THE CASS LAKES AREA EASTWARD TO JUST BELOW DULUTH AND SOUTHWARD ALONG THE SAINT CROIX RIVER HAS STIMULATED SMALLISH...SHALLOW BUT POTENT AND LONG LIVED SHOWERS DROPPING HALF AN INCH OF RAIN PER HOUR ACROSS AT LEAST A DOZEN AREAS. WE DO NOT SEE LIGHTNING ATTM...BUT MIGHT SOON. FALLING HEIGHTS AND COOLING ALOFT FASTER THAN AT THE SURFACE AS A DIGGING AND NEGATIVE-TILTED SHORT WAVE DROPS DOWN TO SUPPORT THIS SLOWLY BUT STEADILY DEEPEENING NEGATIVELY-ORIENTED SURFACE LOW IS ALSO BEING ACCOMPANIED BY SIGNIFICANT SPEED DIVERGENCE ALOFT OVER THE STRONGEST SHOWER AREAS. WE ARE STARTING WITH A RADICAL MOISTENING OF TONIGHT/S FORECAST AND WILL BE LOOKING AT OTHER PARAMETERS IN THE NEXT HOUR OR TWO. && .PREV DISCUSSION... /ISSUED 238 PM CDT FRI SEP 5 2008/ DISCUSSION... SFC LOW NEAR PKD EARLY THIS AFTERNOON WITH ELONGATED SFC TROUGH STRETCHING NORTH TO BDE...AND SOUTH TOWARDS SAZ. MSAS INDICATES A WEAK SECONDARY PRESS FALL CENTER DEVELOPING NEAR RZN. THIS AGREES WELL WITH MDL FCST OF SFC LOW PRESSURE TROUGH ELONGATING SE THIS AFTERNOON. EXTENSIVE CLOUD SHIELD COVERS MOST OF CWA EXCEPT SE WISC WHERE ISENTROPIC ASCENT HAS NOT ARRIVED YET. PRECIP HAS BEEN MINIMAL AS FORCING IS WEAK. LATEST VIS IMAGERY INDICATES INCREASING CONVECTIVE ELEMENTS ENTERING SW CORNER OF CWA. THIS APPEARS TO BE WITHIN A LOW LEVEL THETAE AXIS. 4KM SPC NMM-WRF SIM REFL PRODUCT ACTUALLY DEPICTS THIS CLUSTER AND WORKS IT EAST THIS AFTERNOON TOWARD TWIN PORTS....WEAKENING THE INTENSITY AS IT DOES. A CELL DID PULSE TO 52DBZ AT 11K WITHIN PAST HR NEAR CASS LAKE BUT HAS WEAKENED IN SUBSEQUENT SCANS. LATEST RUC13 SUGGESTS WE NEED 50DBZ CORES TO 16/17K TO GENERATE ANY SIGNIFICANT HAIL. MARGINAL PARAMETERS FOR SIG CONVECTION AS SFC/MUCAPES REMAIN BELOW 1000J/KG...ALTHOUGH 0-6KM SHEAR IS ABOUT 35KTS IN BEST CAPE VICINITY. HAVE LEFT ISO TRW IN FCST THROUGH THIS AFTERNOON BUT NO LIGHTNING HAS BEEN INDICATED WITH ACTIVITY SO FAR. TONIGHT...ELONGATED SFC PRESS TROUGH WILL STRETCH FROM NORTHERN ITASCA TO SAWYER COUNTIES EARLY THIS EVENING. THIS FEATURE WILL CRAWL NORTHEAST OVERNIGHT WITH WEAK CONVERGENCE EXPECTED. PWS RIBBON ASSOCIATED WITH THIS SYSTEM IS NOT THAT IMPRESSIVE SO QPF REMAINS FAIRLY LIGHT. WILL NEED TO ASSESS FOG/BR POTENTIAL BEFORE ZONE ISSUANCE AS POOLING OF MOISTURE NEAR SFC BDRY...COMBINED WITH LIGHT WINDS...MAY PROMOTE LOW VISIBILITIES. TOMORROW...LEANING WITH SREF SCENARIO WITH SUPPORT FROM EC/GFS. THIS KEEPS POPS CONCENTRATED OVER NRN THIRD OF CWA WHERE DEEPER LAYER MOISTURE AND SOME WEAK CONVERGENCE WILL BE PROVIDED BY SFC BDRY. CLOUD FCST WILL BE CHALLENGING AS BREAKS ARE LIKELY PERIODICALLY IN MANY AREAS...ESPECIALLY BY AFTERNOON OVER SRN HALF OF CWA. EXTENDED...A BRIEF LULL SATURDAY EVENING BEFORE NEXT MID LVL DISTURBANCE SWEEPS INTO REGION SUNDAY MORNING.85H TEMPS DROP WITH PASSAGE OF UPPER TROF SO TEMPS WILL COOL SUNDAY/MONDAY/TUES. SLOW MODERATION THEREAFTER ALTHOUGH INCREASING CLOUDS MAY OFFSET ANY WARM ADVECTION ON WEDNESDAY. AVIATION... IFR AND MVFR CONDITIONS HAVE GIVEN WAY TO PREDOMINATELY VFR CONDITIONS ACROSS THE TERMINALS. SCATTERED 15K-25K CLOUDS CAN BE FOUND...WITH A BROKEN TO OVERCAST DECK AT 5K-7K FEET. THERE ARE A FEW POCKETS OF MVFR/IFR IN THE LONGVILLE...TO GRAND RAPIDS...TO BIGFORK AREA...AND OUT TOWARDS BEMIDJI AS OF 20Z. VFR CONDITIONS WILL BE FOUND THROUGH THE REMAINDER OF THE AFTERNOON...WITH OCCASIONAL MVFR CEILINGS GENERALLY AROUND 15K FEET IN RAIN SHOWERS...AS AN UPPER LEVEL DISTURBANCE MOVES EAST THROUGH THE NORTHLAND. CONVECTIVE PARAMETERS ARE WEAK...AND SO HAVE LEFT THE MENTION OF THUNDER OUT...THOUGH THUNDER IS NOT OUT OF THE QUESTION. LOW LEVEL MOISTURE IS EXPECTED TO LINGER INTO THE OVERNIGHT HOURS...PARTICULARLY IN THE NORTH...FROM KINL TO KHIB TO KDLH. HAVE MENTIONED SOME MVFR/IFR STRATUS...WITH SOME FOG AND IFR/LIFR AT KHIB AND KHYR. TOMORROW...COLD UPPER LEVEL TEMPERATURES WILL LEAD TO CUMULUS DEVELOPMENT...WITH THE CHANCE FOR MORE SHOWERS AND ISOLATED THUNDERSTORMS...THOUGH THESE WILL BE AFTER THE 18Z TIME FRAME. && POINT TEMPS/POPS... DLH 47 70 47 60 / 40 20 10 50 INL 46 66 40 60 / 30 30 40 40 BRD 45 70 46 61 / 20 10 40 50 HYR 45 69 43 64 / 40 10 10 50 ASX 48 68 44 65 / 50 20 10 50 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. $$ EOM/TL mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 238 PM CDT FRI SEP 5 2008 .DISCUSSION... SFC LOW NEAR PKD EARLY THIS AFTERNOON WITH ELONGATED SFC TROUGH STRETCHING NORTH TO BDE...AND SOUTH TOWARDS SAZ. MSAS INDICATES A WEAK SECONDARY PRESS FALL CENTER DEVELOPING NEAR RZN. THIS AGREES WELL WITH MDL FCST OF SFC LOW PRESSURE TROUGH ELONGATING SE THIS AFTERNOON. EXTENSIVE CLOUD SHIELD COVERS MOST OF CWA EXCEPT SE WISC WHERE ISENTROPIC ASCENT HAS NOT ARRIVED YET. PRECIP HAS BEEN MINIMAL AS FORCING IS WEAK. LATEST VIS IMAGERY INDICATES INCREASING CONVECTIVE ELEMENTS ENTERING SW CORNER OF CWA. THIS APPEARS TO BE WITHIN A LOW LEVEL THETAE AXIS. 4KM SPC NMM-WRF SIM REFL PRODUCT ACTUALLY DEPICTS THIS CLUSTER AND WORKS IT EAST THIS AFTERNOON TOWARD TWIN PORTS....WEAKENING THE INTENSITY AS IT DOES. A CELL DID PULSE TO 52DBZ AT 11K WITHIN PAST HR NEAR CASS LAKE BUT HAS WEAKENED IN SUBSEQUENT SCANS. LATEST RUC13 SUGGESTS WE NEED 50DBZ CORES TO 16/17K TO GENERATE ANY SIGNIFICANT HAIL. MARGINAL PARAMETERS FOR SIG CONVECTION AS SFC/MUCAPES REMAIN BELOW 1000J/KG...ALTHOUGH 0-6KM SHEAR IS ABOUT 35KTS IN BEST CAPE VICINITY. HAVE LEFT ISO TRW IN FCST THROUGH THIS AFTERNOON BUT NO LIGHTNING HAS BEEN INDICATED WITH ACTIVITY SO FAR. TONIGHT...ELONGATED SFC PRESS TROUGH WILL STRETCH FROM NORTHERN ITASCA TO SAWYER COUNTIES EARLY THIS EVENING. THIS FEATURE WILL CRAWL NORTHEAST OVERNIGHT WITH WEAK CONVERGENCE EXPECTED. PWS RIBBON ASSOCIATED WITH THIS SYSTEM IS NOT THAT IMPRESSIVE SO QPF REMAINS FAIRLY LIGHT. WILL NEED TO ASSESS FOG/BR POTENTIAL BEFORE ZONE ISSUANCE AS POOLING OF MOISTURE NEAR SFC BDRY...COMBINED WITH LIGHT WINDS...MAY PROMOTE LOW VISIBILITIES. TOMORROW...LEANING WITH SREF SCENARIO WITH SUPPORT FROM EC/GFS. THIS KEEPS POPS CONCENTRATED OVER NRN THIRD OF CWA WHERE DEEPER LAYER MOISTURE AND SOME WEAK CONVERGENCE WILL BE PROVIDED BY SFC BDRY. CLOUD FCST WILL BE CHALLENGING AS BREAKS ARE LIKELY PERIODICALLY IN MANY AREAS...ESPECIALLY BY AFTERNOON OVER SRN HALF OF CWA. EXTENDED...A BRIEF LULL SATURDAY EVENING BEFORE NEXT MID LVL DISTURBANCE SWEEPS INTO REGION SUNDAY MORNING.85H TEMPS DROP WITH PASSAGE OF UPPER TROF SO TEMPS WILL COOL SUNDAY/MONDAY/TUES. SLOW MODERATION THEREAFTER ALTHOUGH INCREASING CLOUDS MAY OFFSET ANY WARM ADVECTION ON WEDNESDAY. && .AVIATION... IFR AND MVFR CONDITIONS HAVE GIVEN WAY TO PREDOMINATELY VFR CONDITIONS ACROSS THE TERMINALS. SCATTERED 15K-25K CLOUDS CAN BE FOUND...WITH A BROKEN TO OVERCAST DECK AT 5K-7K FEET. THERE ARE A FEW POCKETS OF MVFR/IFR IN THE LONGVILLE...TO GRAND RAPIDS...TO BIGFORK AREA...AND OUT TOWARDS BEMIDJI AS OF 20Z. VFR CONDITIONS WILL BE FOUND THROUGH THE REMAINDER OF THE AFTERNOON...WITH OCCASIONAL MVFR CEILINGS GENERALLY AROUND 15K FEET IN RAIN SHOWERS...AS AN UPPER LEVEL DISTURBANCE MOVES EAST THROUGH THE NORTHLAND. CONVECTIVE PARAMETERS ARE WEAK...AND SO HAVE LEFT THE MENTION OF THUNDER OUT...THOUGH THUNDER IS NOT OUT OF THE QUESTION. LOW LEVEL MOISTURE IS EXPECTED TO LINGER INTO THE OVERNIGHT HOURS...PARTICULARLY IN THE NORTH...FROM KINL TO KHIB TO KDLH. HAVE MENTIONED SOME MVFR/IFR STRATUS...WITH SOME FOG AND IFR/LIFR AT KHIB AND KHYR. TOMORROW...COLD UPPER LEVEL TEMPERATURES WILL LEAD TO CUMULUS DEVELOPMENT...WITH THE CHANCE FOR MORE SHOWERS AND ISOLATED THUNDERSTORMS...THOUGH THESE WILL BE AFTER THE 18Z TIME FRAME. && POINT TEMPS/POPS... DLH 47 70 47 60 / 20 20 10 50 INL 46 66 40 60 / 20 30 40 40 BRD 45 70 46 61 / 10 10 40 50 HYR 45 69 43 64 / 30 10 10 50 ASX 48 68 44 65 / 30 20 10 50 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. $$ CANNON/GSF/KD mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 937 AM CDT FRI SEP 5 2008 .UPDATE... SMALL UPDATES TO ACCOUNT FOR SOME LOCALIZED FOG ACROSS PARTS OF RANGE/SRN WI ZONES. ADDITIONALLY... SLOWER PROGRESSION OF POPS/QPF/CLOUDS INTO NE ARROWHEAD AND ERN WI ZONES. LINEAR BAND OF RAIN ASSOCIATED WITH SFC/925 THETAE AXIS AHEAD OF APPROACHING LOW. USING LATEST RUC13...THIS LOW LVL INSTABILITY AXIS MOVES VERY SLOWLY EAST TODAY...WITH A TENDENCY TO STRENGTHEN OVER SCTRL WIS ZONES LATE THIS AFTERNOON. MAY SEE SOME CONVECTION DEVELOP OVER THIS REGION LATER TODAY AS MDLS SUGGEST BEST 85H MSTR TRANSPORT WILL PUSH INTO WISCONSIN. NAM40 FCST SBCAPE VALUES RANGE BETWEEN 500/1000 J/KG WITH 0-6KM SHEAR OF 35/40KTS. && .PREV DISCUSSION... /ISSUED 247 AM CDT FRI SEP 5 2008/ DISCUSSION... SFC STATIONS REPORTING PATCHY FG THIS MORNING WITH GENERALLY LIGHT E TO SE WINDS. WEAK SFC LOW/TROUGH...CO-LOCATED WITH A POTENT SHORT WAVE SEEN ON IR IMAGERY ROTATING OVER NE NO DAK...PUSHES E INTO WRN MN. MOSAIC RADAR SHOWS THE VORT MAX/SFC LOW HAS BROUGHT SHRA TO NE NO DAK/NW MN OVERNIGHT...WITH THE LEADING EDGE CURRENTLY NEAR BJI LIFTING NORTH AND EAST. MODELS CONTINUE TO BE IN GOOD AGREEMENT AND HAVE KEPT RUN TO RUN CONTINUITY. THE SYSTEM WILL PROGRESS EWRD OVER THE WRN GREAT LAKES REGION TODAY AND TONIGHT. THE BEST LIFT AND INSTABILITY WILL BE FOUND OVER THE IRON RANGE AND INTO ADJACENT SRN CANADA...WITH WEAKER FORCING IN THE SRN ZONES. INCREASED POPS TO LIKELY ACROSS THE NRN TIER OF COUNTIES TODAY...WITH DECREASING POPS SOUTH AND EAST. QPF AMOUNTS WILL BE SCT AND GENERALLY LIGHT...RANGING FROM A FEW HUNDREDTHS TO AROUND A TENTH. KEPT ISOLD TSRA WORDING THIS AFTRN. BUFR SOUNDINGS SUGGEST FAVORABLE MID LVL LAPSE RATES WITH A FEW HUNDRED J OF CAPE DEVELOP THIS AFTN TO SUPPORT ISOLD -TSRA THIS AFTN...REMAINING WELL BLW SVR LVLS. THE FA WILL REMAIN UNDER THE CYCLONIC CURVATURE OF THE BROAD UPR LVL TROUGH THROUGH SAT. KEPT THE 20-30 POP FOR SHRA THROUGH THIS TIME FRAME. ANOTHER LOBE OF ENERGY ROUNDS THE BASE OF THE UPR LVL TROUGH OVER MN AND THE WRN GREAT LKS REGION LATE SAT NIGHT THROUGH SUNDAY NIGHT...CONTINUING THE CHC FOR SHRA. AVIATION...A SHORTWAVE WILL PUSH EAST ACROSS THE AREA TODAY...AND WHILE MAINLY VFR CONDITIONS CAN BE EXPECTED...SOME TEMPO MVFR-IFR CEILINGS MAY OCCUR IN SCATTERED SHOWERS THROUGHOUT MUCH OF THE DAY. THE MOST PERSISTENT AND WIDESPREAD SHOWERS WILL BE CONFINED TO THE FAR NORTHWEST PORTION OF THE AREA...INCLUDING KINL...WHERE THE BEST OMEGA AND VORTICITY ADVECTION WILL BE FOUND. SOME THUNDER IS CERTAINLY POSSIBLE ACROSS THE ENTIRE AREA...ESPECIALLY AFTER 14Z...BUT IT SHOULD REMAIN RATHER ISOLATED AS INSTABILITY PARAMETERS ARE WEAK. WITH A DEPARTING HIGH TO THE NORTH...A NORTHEAST FLOW WILL RESULT IN LOW CLOUDS NEAR LAKE SUPERIOR...ESPECIALLY AT KDLH...THROUGH MID-MORNING. PATCHY FOG AND LOCAL IFR-VLIFR CONDITIONS MAY ALSO OCCUR IN PORTIONS OF NORTHWEST WISCONSIN THROUGH ABOUT 14Z TODAY. DEWPOINTS HAVE RISEN IN THESE AREAS...AND FORECAST SOUNDINGS DO SHOW THE DEVELOPMENT OF STRATUS AND FOG FOR THE MORNING HOURS. AS THE SFC LOW WEAKENS AND BECOMES MORE OF A BROAD TROUGH...THE CHANCE FOR SHOWERS WILL LESSEN AS THE SHORTWAVE PUSHES EAST...WITH ONLY ISOLATED-SCATTERED SHOWERS FOR KHYR THIS AFTERNOON. CONDITIONS WILL IMPROVE IN ALL AREAS AFTER 00Z...WITH JUST SOME REMNANT SCATTERED CLOUDS. && POINT TEMPS/POPS... DLH 64 47 71 47 / 30 20 30 30 INL 64 46 67 40 / 70 20 30 40 BRD 65 45 68 46 / 20 10 20 40 HYR 68 45 70 43 / 20 30 20 30 ASX 65 48 69 44 / 20 30 30 30 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. $$ CANNON mn AREA FORECAST DISCUSSION...AVIATION UPDATE. NATIONAL WEATHER SERVICE SPRINGFIELD MO 1203 AM CDT FRI SEP 5 2008 .DISCUSSION... ONGOING FIRST PERIOD FORECAST LOOKS RIGHT ON TRACK. THE ONLY CHANGE THAT MAY BE NEEDED WITHIN THE GRIDS REGARDS SKY COVER. ISENTROPIC DOWNGLIDE WITHIN THE LOWEST FEW KILOMETERS CONTINUE TO ERODE CLOUD COVER FROM THE WEST. EVENTUALLY THIS DOWNGLIDE OCCURS ACROSS MOST OF THE CWA AFTER MIDNIGHT...ACCORDING TO THE RUC. THEREFORE FULL SKY COVERAGE THROUGH THE ENTIRE NIGHT MAY BE A LITTLE AGGRESSIVE. WILL CONTINUE TO MONITOR FOR CHANGES WITHIN THE GRIDS. WE WILL ALSO MONITOR FOG POTENTIAL. CAN NOT RULE OUT DENSE FOG DEVELOPING AS SKIES CLEAR. VERY MOIST SOIL CONDITIONS ALONG WITH A DECREASE IN BOUNDARY LAYER MIXING WOULD ENHANCE FOG DEVELOPMENT. THE GREATEST RISK AREA FOR DENSE FOG INITIALLY...WILL OCCUR OVER EXTREME SOUTHEAST KANSAS AND WESTERN MISSOURI. CRAMER && .AVIATION... THE PRIMARY FORECAST CHALLENGE WITHIN THE AVIATION FORECASTS REGARDED CEILING HEIGHTS AND POTENTIAL FOG OVERNIGHT. CEILINGS OVER THE SPRINGFIELD AIRPORT SHOULD CONTINUE WITHIN THE IFR CATEGORY THROUGH TONIGHT...AND POSSIBLY CLEAR OUT SOMETIME AFTER 12Z. DRIER AIR ALOFT IS ADVECTING IN FROM EASTERN KANSAS...WHICH SHOULD ELIMINATE CLOUD COVER AT JOPLIN. HOWEVER...ONCE THE SKIES CLEAR...FOG WILL DEVELOP AS WIND SPEEDS BECOME LIGHT...ELIMINATING ANY BOUNDARY LAYER MIXING THAT MIGHT EXIST. AS A MATTER OF FACT...VISIBILITIES ARE RAPIDLY DETERIORATING OVER SOUTHEAST KANSAS...AS FORT SCOTT HAS FELL TO 1/2 OF A MILE. MOIST SOIL CONDITIONS WILL ALSO ENHANCE FOG DEVELOPMENT WHILE OVERNIGHT LOWS ARE EXPECTED TO COOL WELL BELOW THE CROSS-OVER TEMPERATURE. WILL MONITOR CEILINGS AND VISIBILITIES CLOSELY THROUGH THE NIGHT AND ISSUE UPDATED TAFS WHEN NEEDED. CRAMER && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GLASGOW MT 943 AM MDT FRI SEP 5 2008 .SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH SUNDAY... ONLY MINOR UPDATE TO CLOUD COVER FOR TODAY. ALSO FOR END OF PATCHY FOG. SHORTWAVE ENERGY PUSHING MOISTURE INTO CENTRAL MONTANA WITH CLOUDS NUDGING TOWARD EASTERN MONTANA. AIRMASS NOT AS UNSTABLE AS YESTERDAY SO AFTERNOON SHOWERS ARE LESS LIKELY THIS AFTERNOON THAN YESTERDAY. ALSO MORE SUNSHINE...SO EXPECT SLIGHTLY WARMER TEMPERATURES AS WELL. EBERT PREVIOUS SHORT TERM DISCUSSION...NOT MUCH CHANGE IN THE LONGWAVE PATTERN THRU THE WEEKEND...WITH UPPER RIDGING OFF THE W COAST...UPPER TROUGHING OVER THE MIDWEST. NE MT IS ON THE BACKSIDE OF TROUGH IN NW FLOW...WITH THE JETSTREAM REMAINING STRONGER AND FARTHER S THAN USUAL FOR EARLY SEP. THIS MORN...SOME LOCATIONS SHOW OBS THAT ARE NEARLY SATURATED. THIS NOT AS EXTENSIVE AS YESTERDAY THOUGH. RUC SHOWS 95 PCT RH ACROSS ROUGHLY OUR NE QUARTER AT 12Z. WILL COMBINE THIS WITH THE OBS THAT HAVE BEEN REPORTING TEMP/DEW POINT SPREADS OF 0-2F AT 3 AM TO ADD PATCHY EARLY MORN FOG MENTION. THIS WILL BE IN LOWER MILK...MISSOURI...AND BIG MUDDY RIVER VALLEYS. OTHERWISE... GENERALLY CLEAR SKIES EARLY THIS MORN...BUT IR SATELLITE CHANNEL SHOWS A RATHER LARGE AREA OF MID-LEVEL OVERCAST IN AB AND NC/NW MT THAT WILL BE MOVING ACROSS OUR N THIS MORN. NO PRECIP EXPECTED FROM IT. OTHERWISE MORE SUNSHINE WILL ALLOW A FEW DEGREES WARMING OVER YESTERDAY. AIRMASS SLIGHTLY DRIER AND SLIGHTLY LESS UNSTABLE FOR THE AFTERNOON WITHOUT ANY SHORTWAVES. THIS SHOULD LIMIT SHOWER DEVELOPMENT TO LESS THAN YESTERDAY...BUT THERE WILL BE A FEW WEAK CELLS...MAINLY E. WILL GO WITH POPS LOW ENOUGH THAT THEY WON`T SHOW AS WORDING IN TEXT PRODUCTS. MODELS CONTINUE TO BRING A MODERATE SHORTWAVE FROM THE NW ACROSS THE AREA LATE TONIGHT AND SAT FOR SCATTERED SHOWERS. ALL MODELS SHOW A FAIR AREA OF QPF. THE SYSTEM DOESN`T APPEAR ALL THAT WELL ORGANIZED...SO WILL KEEP POPS IN SCATTERED CATEGORY...BUT KEEPING IN MIND ALSO THAT TYPICALLY THESE SYSTEMS FROM THE NW ARE OFTEN UNDERFORECAST FOR POPS. WITH 850 MB WINDS TO 20KT OR SO WITH WEAK COOL ADVECTION IN THE AFTERNOON...WILL BE NEAR LAKE WIND ADVISORY CRITERIA SAT. SKIES CLEAR ACROSS OUR N SAT NIGHT. THICKNESSES DROP TO AROUND 543 DM AND 850 TEMPS TO 5C. THIS IS AT LEAST AS LOW AS THE PREVIOUS FEW COOL NIGHTS. WITH SURFACE HIGH OVER AREA AND DEW POINTS LOWER THAN LATELY...WOULD EXPECT WIDESPREAD 30S FOR LOWS...SOME TO AROUND FREEZING IN THE TYPICAL COLDEST POCKETS. MEANWHILE.. INCREASING CLOUDS IN OUR S. MODELS VARY QUITE A BIT ON INTENSITY...BUT ALL HAVE A SHORTWAVE MOVE SE ALONG THE JETSTREAM THRU THE MIDDLE OF THE STATE LATE SAT NIGHT AND SUN. THESE OFTEN DO AFFECT OUR SW...BUT SELDOM ELSEWHERE AS FAR AS PRECIP GOES. WILL GO WITH A CHANCE OF RAIN SUN IN OUR SW. PREFER TO GO A LITTLE BELOW MOS ALL AREAS SUN AS WELL. SIMONSEN .LONG TERM...SUNDAY NIGHT THROUGH FRIDAY... NORTHWEST FLOW ALOFT WILL CONTINUE OVER THE FORECAST AREA MOST OF THE TIME THROUGH THE PERIOD. LOOK FOR DRY WEATHER AND A WARMING TREND WITH A SURFACE HIGH ON MONDAY AND A SHORTWAVE UPPER RIDGE ON TUESDAY. MODELS HAVE HAD SOME DIFFERENCES ON TRACKING A MIDWEEK SHORTWAVE TROUGH AND COLD FRONT. 00Z GFS...00Z CANADIAN AND 12Z ECMWF HAD THE FRONT AND SHORTWAVE AFFECTING THE FORECAST AREA ON WEDNESDAY. 00Z ECMWF HAS SLOWED IT DOWN. THE LAST 3 RUNS OF THE GFS HAVE HAD THE MAIN PART OF THE WAVE AFFECTING NE MONTANA EITHER WEDNESDAY OR WEDNESDAY NIGHT WITH THE COLD FRONT FORECASTED FOR WEDNESDAY FOR SEVERAL RUNS. WILL MAINTAIN A WED FRONTAL PASSAGE AND MENTION A SLIGHT CHANCE OF THUNDERSTORMS ON WED AND SHOWERS WED NIGHT. NORTHWEST FLOW ALOFT WILL PREVAIL AFTER THE TROUGH EXITS WITH MAINLY DRY WEATHER. FORRESTER && .AVIATION... VFR CONDITIONS ARE EXPECTED TO PREVAIL TODAY INTO THIS EVENING. BROKEN CUMULUS AROUND 4K OR 5K FT AGL IS EXPECTED THIS AFTERNOON INTO EARLY EVENING. NORTHWEST WIND WILL BE AROUND 10 KT TODAY. LOOK FOR EITHER MID LEVEL OR LOW VFR CEILINGS TO PREVAIL LATER TONIGHT WITH A CHANCE OF RAIN THAT WILL CONTINUE THROUGH SATURDAY. FRANSEN && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && $$ WEATHER.GOV/GLASGOW mt AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GLASGOW MT 406 AM MDT FRI SEP 5 2008 .SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH SUNDAY... NOT MUCH CHANGE IN THE LONGWAVE PATTERN THRU THE WEEKEND...WITH UPPER RIDGING OFF THE W COAST...UPPER TROUGHING OVER THE MIDWEST. NE MT IS ON THE BACKSIDE OF TROUGH IN NW FLOW...WITH THE JETSTREAM REMAINING STRONGER AND FARTHER S THAN USUAL FOR EARLY SEP. THIS MORN...SOME LOCATIONS SHOW OBS THAT ARE NEARLY SATURATED. THIS NOT AS EXTENSIVE AS YESTERDAY THOUGH. RUC SHOWS 95 PCT RH ACROSS ROUGHLY OUR NE QUARTER AT 12Z. WILL COMBINE THIS WITH THE OBS THAT HAVE BEEN REPORTING TEMP/DEW POINT SPREADS OF 0-2F AT 3 AM TO ADD PATCHY EARLY MORN FOG MENTION. THIS WILL BE IN LOWER MILK...MISSOURI...AND BIG MUDDY RIVER VALLEYS. OTHERWISE... GENERALLY CLEAR SKIES EARLY THIS MORN...BUT IR SATELLITE CHANNEL SHOWS A RATHER LARGE AREA OF MID-LEVEL OVERCAST IN AB AND NC/NW MT THAT WILL BE MOVING ACROSS OUR N THIS MORN. NO PRECIP EXPECTED FROM IT. OTHERWISE MORE SUNSHINE WILL ALLOW A FEW DEGREES WARMING OVER YESTERDAY. AIRMASS SLIGHTLY DRIER AND SLIGHTLY LESS UNSTABLE FOR THE AFTERNOON WITHOUT ANY SHORTWAVES. THIS SHOULD LIMIT SHOWER DEVELOPMENT TO LESS THAN YESTERDAY...BUT THERE WILL BE A FEW WEAK CELLS...MAINLY E. WILL GO WITH POPS LOW ENOUGH THAT THEY WON`T SHOW AS WORDING IN TEXT PRODUCTS. MODELS CONTINUE TO BRING A MODERATE SHORTWAVE FROM THE NW ACROSS THE AREA LATE TONIGHT AND SAT FOR SCATTERED SHOWERS. ALL MODELS SHOW A FAIR AREA OF QPF. THE SYSTEM DOESN`T APPEAR ALL THAT WELL ORGANIZED...SO WILL KEEP POPS IN SCATTERED CATEGORY...BUT KEEPING IN MIND ALSO THAT TYPICALLY THESE SYSTEMS FROM THE NW ARE OFTEN UNDERFORECAST FOR POPS. WITH 850 MB WINDS TO 20KT OR SO WITH WEAK COOL ADVECTION IN THE AFTERNOON...WILL BE NEAR LAKE WIND ADVISORY CRITERIA SAT. SKIES CLEAR ACROSS OUR N SAT NIGHT. THICKNESSES DROP TO AROUND 543 DM AND 850 TEMPS TO 5C. THIS IS AT LEAST AS LOW AS THE PREVIOUS FEW COOL NIGHTS. WITH SURFACE HIGH OVER AREA AND DEW POINTS LOWER THAN LATELY...WOULD EXPECT WIDESPREAD 30S FOR LOWS...SOME TO AROUND FREEZING IN THE TYPICAL COLDEST POCKETS. MEANWHILE.. INCREASING CLOUDS IN OUR S. MODELS VARY QUITE A BIT ON INTENSITY...BUT ALL HAVE A SHORTWAVE MOVE SE ALONG THE JETSTREAM THRU THE MIDDLE OF THE STATE LATE SAT NIGHT AND SUN. THESE OFTEN DO AFFECT OUR SW...BUT SELDOM ELSEWHERE AS FAR AS PRECIP GOES. WILL GO WITH A CHANCE OF RAIN SUN IN OUR SW. PREFER TO GO A LITTLE BELOW MOS ALL AREAS SUN AS WELL. SIMONSEN .LONG TERM...SUNDAY NIGHT THROUGH FRIDAY... NORTHWEST FLOW ALOFT WILL CONTINUE OVER THE FORECAST AREA MOST OF THE TIME THROUGH THE PERIOD. LOOK FOR DRY WEATHER AND A WARMING TREND WITH A SURFACE HIGH ON MONDAY AND A SHORTWAVE UPPER RIDGE ON TUESDAY. MODELS HAVE HAD SOME DIFFERENCES ON TRACKING A MIDWEEK SHORTWAVE TROUGH AND COLD FRONT. 00Z GFS...00Z CANADIAN AND 12Z ECMWF HAD THE FRONT AND SHORTWAVE AFFECTING THE FORECAST AREA ON WEDNESDAY. 00Z ECMWF HAS SLOWED IT DOWN. THE LAST 3 RUNS OF THE GFS HAVE HAD THE MAIN PART OF THE WAVE AFFECTING NE MONTANA EITHER WEDNESDAY OR WEDNESDAY NIGHT WITH THE COLD FRONT FORECASTED FOR WEDNESDAY FOR SEVERAL RUNS. WILL MAINTAIN A WED FRONTAL PASSAGE AND MENTION A SLIGHT CHANCE OF THUNDERSTORMS ON WED AND SHOWERS WED NIGHT. NORTHWEST FLOW ALOFT WILL PREVAIL AFTER THE TROUGH EXITS WITH MAINLY DRY WEATHER. FORRESTER && .AVIATION... VFR CONDITIONS ARE EXPECTED TO PREVAIL MOST OF THE TIME TODAY AND TONIGHT. FOG REMAINS A SLIGHT POSSIBILITY THIS MORNING...WITH THE MOST LIKELY SITES BEING KOLF AND KSDY. BROKEN CUMULUS AROUND 4K OR 5K FT AGL IS EXPECTED THIS AFTERNOON INTO EARLY EVENING. NORTHWEST WIND WILL BE AROUND 10 KT TODAY. LOOK FOR EITHER MID LEVEL OR LOW VFR CEILINGS TO PREVAIL TONIGHT WITH A CHANCE OF RAIN. && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && $$ WEATHER.GOV/GLASGOW mt AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 837 PM CDT SAT SEP 6 2008 .DISCUSSION... HAVE ISSED AN UPDATED MAINLY TO PRECIP TRENDS ACROSS THE CWA. AREA OF MORE INTENSE SHRA WAS ONGOING ROUGHLY ALONG THE I-80 CORRIDOR...BUT OTHERWISE SHRA HAVE ESSENTIALLY MOVED OUT OF THE CWA. INCREASED POPS THROUGH 06Z ALONG/AHEAD OF THE BAND OF SHRA...BUT TONED DOWN ELSEWHERE TO JUST ISO MENTION AND DROPPED THE POPS AFTER 06Z IN THE NRN CWA. HAVE SEEN AN ISOLATED STRIKE OR TWO W OF KLNK WITH THE HEAVIER SHRA...BUT FOR NOW HAVE KEPT OUT OF GRIDS AS COVERAGE IS NOT EXPECTED TO BE WIDESPREAD. OTHERWISE...MADE NO CHANGES TO THE GOING FORECAST AS PATCHY FOG STILL LOOKS POSSIBLE TONIGHT WITH WEAK WINDS AND LOW TEMP/DEWPOINT SPREADS. UPDATED GRIDS/ZFP ALREADY SENT. && .PREV DISCUSSION... /ISSUED 200 PM CDT SAT SEP 6 2008/ DISCUSSION... SHORT TERM CONCERNS WILL REMAIN FOCUSED ON SEASONABLY COOL WEATHER PATTERN INTO EARLY NEXT WEEK...PRECIP...TEMPS...FOG. LATEST RUC HAS ONE SEGMENT OF A STG JET EXITING THE AREA...WITH ANOTHER 115+KT JET DIVING INTO MT/WY/CO. THIS JET WILL KEEP THINGS MOVING AND COMBINED WITH SHORTWAVE TROF ENERGY AND COLD AIR ALOFT HAS PRODUCED SHOWER AND ISOLATED TSRA ACRS THE STATE. SOME LINGERING LIFT WILL CONTINUE OVERNIGHT...HOWEVER EXPECT THE BETTER CHC FOR PRECIP TO REMAIN TO OUR N OR SOUTH. WILL ASSESS OVERNIGHT POPS BEFORE SENDING OUT...BUT FOR NOW HAVE SOME SCT SHOWERS EARLY THIS EVENING...THEN TRIM BACK TO A SLIGHT CHC LATER TONIGHT. WITH LIGHT WINDS AND HIGH LOW LEVEL MOISTURE...EXPECT FOG TO RE-DEVELOP. CLDS WILL COMPLICATE THE FACT THAT DENSE FOG WILL BE POSSIBLE IN FAVORABLE LOW LYING AREAS AND WHERE HIGHER CLDS THIN. THINK THERE WILL BE MORE CLDS AROUND NORTHEAST ZONES...THUS WILL HIT THE FOG HARDER CENTRAL AND SRN ZONES. LOWS TONIGHT IN THE 40S TO LOWER 50S. AM COUNTING ON A BREAK IN THE PRECIP SUNDAY...HOWEVER THERE IS STILL A SUBTLE WAVE MOVING THRU THE REGION AND LEFT AN ISOLATED SHOWER FOR NE NEB INTO WRN IA. TEMPERATURES NOT QUITE AS COOL WITH HIGHS IN THE 60S TO LOWER 70S. SUNDAY NIGHT INTO MONDAY...TROF ENERGY IN WRN CANADA WILL MOVE INTO MT/WY SUN AND ACRS THE PLAINS MON. LOW LEVEL AND MID LEVEL FORCING COMBINE TO PRODUCE SHOWERS AND THUNDERSTORMS IN KANSAS AND A SECOND AREA IN WY/NW NEB SUNDAY NIGHT...AND CONVERGE TO DEVELOP A STRONG BAROCLINIC ZONE FM NEB INTO IA MON. CONTINUE TO BOOST POPS TO THE LIKELY AND ABOVE CATEGORY FOR AREAS IN THE VICINITY OF THIS FRONT MONDAY. INSTABILITY APPEARS GREATEST FM KS INTO MO AND IL...AND THIS IS WHERE THE DAY3 OUTLOOKS HAS A PROB. FOR SVR. DUE TO THE FAVORABLE DEEP LAYER SHEAR...LOOKED AT HAIL POTENTIAL. LOW FREEZING LEVELS MOVE IN MON...BUT APPEARS BEST DEEP MOISTURE REMAINS TO THE SOUTH BEFORE IT CAN BE FULLY UTILIZED. THE MID LEVEL TROF SHIFTS TO THE EAST SPREADING THE PRECIP EAST INTO THE GRTLKS MONDAY NIGHT. AGAIN...A BREAK IN THE PRECIP TUESDAY WITH HIGHS IN THE 70S. THE EXTENDED FCST TUE NIGHT THRU SAT IS LOOKING MORE SEASONABLE. A STRONG MID TROPOSPHERIC TROF WILL BE APPROACHING THE REGION TUES NIGHT WITH A STRENGTHENING JET AND WAA OVERNIGHT AND WED...THEN MOVE THROUGH WED NIGHT INTO THUR. SCT SHOWERS AND ISOLD TSRA EXPECTED AHEAD OF THE FRONT AND WITH IT/S PASSAGE THRU THU MORNING. KEPT TEMPS NEAR NORMAL WITH 70S TO LOWER 80S WED WITH WRMR SW FLOW...ALTHOUGH CLDS AND PRECIP WOULD HINDER HIGHS. WENT BELOW GUID THU BEHIND THE FNT...BUT STILL LEFT HIGHS IN THE 70S WITH DECREASING CLDS. THE PATTERN IS MOSTLY DRY FRI THRU SATURDAY WITH WEAK HIGH PRES OVR THE REGION FRI AND WEAK LOW PRES DEVELOPING OVR THE NRN PLAINS INTO WRN NEB SAT. HURRICANE IKE IS STILL FCST TO MOVE INTO THE GULF THRU THE EXTENDED. SOLUTIONS DIFFER ON IT/S TRACK AND WHERE THE REMNANTS GO...BUT INTO EARLY NEXT WEEK...TO NOT MAKE IT INTO THE LOCAL AREA. HIGHS IN THE EXTENDED FM THE 70S TO LOWER 80S. AVIATION... FOR TAF SITES KOMA/KLNK/KOFK. VALID THRU 07/18Z. RAIN SHOWERS WILL PROGRESSIVELY MOVE ACROSS KOMA/KOFK/AND KLNK SITES THRU 02-03Z. WINDS ARE FORECAST TO BECOME LIGHT SOUTHWESTERLY THIS EVENING. BR IS LIKELY AGAIN TONIGHT...WITH LOWEST VISIBILITIES AT KOMA BEING 3/4 OF A MILE. VISIBILITIES SHOULD BE 1-3 MILES AT KOFK AND KLNK. VISIBILITIES AND CEILINGS ARE EXPECTED TO IMPROVE AFTER 15Z SUNDAY. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ MAYES ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 200 PM CDT SAT SEP 6 2008 .DISCUSSION... SHORT TERM CONCERNS WILL REMAIN FOCUSED ON SEASONABLY COOL WEATHER PATTERN INTO EARLY NEXT WEEK...PRECIP...TEMPS...FOG. LATEST RUC HAS ONE SEGMENT OF A STG JET EXITING THE AREA...WITH ANOTHER 115+KT JET DIVING INTO MT/WY/CO. THIS JET WILL KEEP THINGS MOVING AND COMBINED WITH SHORTWAVE TROF ENERGY AND COLD AIR ALOFT HAS PRODUCED SHOWER AND ISOLATED TSRA ACRS THE STATE. SOME LINGERING LIFT WILL CONTINUE OVERNIGHT...HOWEVER EXPECT THE BETTER CHC FOR PRECIP TO REMAIN TO OUR N OR SOUTH. WILL ASSESS OVERNIGHT POPS BEFORE SENDING OUT...BUT FOR NOW HAVE SOME SCT SHOWERS EARLY THIS EVENING...THEN TRIM BACK TO A SLIGHT CHC LATER TONIGHT. WITH LIGHT WINDS AND HIGH LOW LEVEL MOISTURE...EXPECT FOG TO RE-DEVELOP. CLDS WILL COMPLICATE THE FACT THAT DENSE FOG WILL BE POSSIBLE IN FAVORABLE LOW LYING AREAS AND WHERE HIGHER CLDS THIN. THINK THERE WILL BE MORE CLDS AROUND NORTHEAST ZONES...THUS WILL HIT THE FOG HARDER CENTRAL AND SRN ZONES. LOWS TONIGHT IN THE 40S TO LOWER 50S. AM COUNTING ON A BREAK IN THE PRECIP SUNDAY...HOWEVER THERE IS STILL A SUBTLE WAVE MOVING THRU THE REGION AND LEFT AN ISOLATED SHOWER FOR NE NEB INTO WRN IA. TEMPERATURES NOT QUITE AS COOL WITH HIGHS IN THE 60S TO LOWER 70S. SUNDAY NIGHT INTO MONDAY...TROF ENERGY IN WRN CANADA WILL MOVE INTO MT/WY SUN AND ACRS THE PLAINS MON. LOW LEVEL AND MID LEVEL FORCING COMBINE TO PRODUCE SHOWERS AND THUNDERSTORMS IN KANSAS AND A SECOND AREA IN WY/NW NEB SUNDAY NIGHT...AND CONVERGE TO DEVELOP A STRONG BAROCLINIC ZONE FM NEB INTO IA MON. CONTINUE TO BOOST POPS TO THE LIKELY AND ABOVE CATEGORY FOR AREAS IN THE VICINITY OF THIS FRONT MONDAY. INSTABILITY APPEARS GREATEST FM KS INTO MO AND IL...AND THIS IS WHERE THE DAY3 OUTLOOKS HAS A PROB. FOR SVR. DUE TO THE FAVORABLE DEEP LAYER SHEAR...LOOKED AT HAIL POTENTIAL. LOW FREEZING LEVELS MOVE IN MON...BUT APPEARS BEST DEEP MOISTURE REMAINS TO THE SOUTH BEFORE IT CAN BE FULLY UTILIZED. THE MID LEVEL TROF SHIFTS TO THE EAST SPREADING THE PRECIP EAST INTO THE GRTLKS MONDAY NIGHT. AGAIN...A BREAK IN THE PRECIP TUESDAY WITH HIGHS IN THE 70S. THE EXTENDED FCST TUE NIGHT THRU SAT IS LOOKING MORE SEASONABLE. A STRONG MID TROPOSPHERIC TROF WILL BE APPROACHING THE REGION TUES NIGHT WITH A STRENGTHENING JET AND WAA OVERNIGHT AND WED...THEN MOVE THROUGH WED NIGHT INTO THUR. SCT SHOWERS AND ISOLD TSRA EXPECTED AHEAD OF THE FRONT AND WITH IT/S PASSAGE THRU THU MORNING. KEPT TEMPS NEAR NORMAL WITH 70S TO LOWER 80S WED WITH WRMR SW FLOW...ALTHOUGH CLDS AND PRECIP WOULD HINDER HIGHS. WENT BELOW GUID THU BEHIND THE FNT...BUT STILL LEFT HIGHS IN THE 70S WITH DECREASING CLDS. THE PATTERN IS MOSTLY DRY FRI THRU SATURDAY WITH WEAK HIGH PRES OVR THE REGION FRI AND WEAK LOW PRES DEVELOPING OVR THE NRN PLAINS INTO WRN NEB SAT. HURRICANE IKE IS STILL FCST TO MOVE INTO THE GULF THRU THE EXTENDED. SOLUTIONS DIFFER ON IT/S TRACK AND WHERE THE REMNANTS GO...BUT INTO EARLY NEXT WEEK...TO NOT MAKE IT INTO THE LOCAL AREA. HIGHS IN THE EXTENDED FM THE 70S TO LOWER 80S. && .AVIATION... FOR TAF SITES KOMA/KLNK/KOFK. VALID THRU 07/18Z. RAIN SHOWERS WILL PROGRESSIVELY MOVE ACROSS KOMA/KOFK/AND KLNK SITES THRU 02-03Z. WINDS ARE FORECAST TO BECOME LIGHT SOUTHWESTERLY THIS EVENING. BR IS LIKELY AGAIN TONIGHT...WITH LOWEST VISIBILITIES AT KOMA BEING 3/4 OF A MILE. VISIBILITIES SHOULD BE 1-3 MILES AT KOFK AND KLNK. VISIBILITIES AND CEILINGS ARE EXPECTED TO IMPROVE AFTER 15Z SUNDAY. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ ZAPOTOCNY/SMITH ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 208 PM EDT SAT SEP 6 2008 .SYNOPSIS... TROPICAL STORM HANNA WILL MOVE NORTH ALONG THE EAST COAST TODAY. HEAVY RAIN WILL MOVE INTO NORTHEAST PENNSYLVANIA AND THE CATSKILLS OF NEW YORK THIS AFTERNOON AND EVENING. THE RAINFALL IS EXPECTED TO COME TO AN END SUNDAY MORNING. HIGH PRESSURE WITH DRY WEATHER WILL BE ACROSS THE REGION LATE SUNDAY INTO MONDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1015 AM EDT... TROPICAL STORM HANNA LOOKS TO BE LOCATED ALONG THE NC/VA BORDER AND IS STILL HEADING OFF TO THE NORTH. STILL WAITING TO SEE IF HANNA WILL CONTINUE HEADING NORTH...BUT IT LOOKS AS IF IT MAY BE SLOWLY BEGINNING TO HEAD NORTHEAST. EITHER WAY...A BIG AREA OF RAIN IS MVG INTO S-CNTRL AND SEPA AND IS HEADING UP INTO NEPA. THIS AREA OF RAIN SHUD MV IN WITHIN THE NEXT HR. MODELS STILL HVG TROUBLE WITH THIS AREA OF RAIN WITH THE 06Z NAM INDICATING VRY LITTLE QPF THIS FAR NORTH ALREADY. THE GFS IS ALSO NOT CATCHING ONTO THE NORTHWARD EXTENT OF THE PCPN SHIELD. LATEST RUC HAS A PRETTY GOOD HANDLE ON PCPN WITH IT LOCATED JUST SOUTH OF CWA AT 14Z. IN TURN IT IS ALSO FURTHER WEST THAN THE OTHER MODELS INDICATE AND GIVES MORE RAIN TO SERN ZONES. IN RECOGNITION OF THE FACT THAT MOST OF THE PCPN IS TO THE NORTH AND WEST OF THE CENTER AS EXPECTED AND THE STORM CONTINUES TO MV N-NE WILL KEEP FLOOD WATCH AS IS. THERE WILL BE A VERY TIGHT GRADIENT OF 1 INCH TO 5 INCHES AND THIS CUD FALL ON EITHER SIDE OF THE CWA BOUNDARY. THIS WILL BE A CLOSE ONE FOR OUR SERN ZONES. FEELING IS THAT SOMEWHERE IN THE SRN PART OF THE FLOOD WATCH AREA WILL LIKELY SEE HVY RAIN BFR THE DAY IS OUT WITH FLOODING PROBLEMS. STAY TUNED... AS FOR THE WINDS...HIGHEST GUSTS HV BEEN CONFINED ALONG THE COAST...IMMEDIATELY EAST OF THE CENTER. KLWX VAD WIND PROFILES INDICATE ONLY 25-30KTS OFF THE SFC. THUS...WILL LEAVE THINGS AS IS WITH GUSTY WINDS MENTIONED IN THE HWO FOR THE POCONOS BUT NO WIND ADVISORIES AT THIS TIME. RUC H8 WINDS ONLY FCST TO BE ARND 20-25KTS AT 2KFT. IT WILL BE CLOSE TO ADVISORY CRITERIA BUT CONFIDENCE IS STILL NOT THERE FOR ANY WIDESPREAD PROBLEMS FROM WINDS THIS AFTN. PREV DISCUSSION... FIRST WEST TO EAST AREA OF RAIN IS LIFTING THROUGH THE CWA ATTM. THIS IS WELL AHEAD OF HANNA AND THE HEAVIER RAIN THAT IS EXPECTED THIS AFTN AND EVE. THIS FIRST BATCH SHOULD BE HANDLED EASILY EVEN WITH AN AREA OF 1 INCH RADAR RAINFALL ESTIMATES IN THE CATSKILLS. IT HAS BEEN DRY FOR THE PAST WEEK WITH 1 HOUR FFG OVER 2 INCHES. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... FLOOD WATCH CONTINUES FOR THE SAME AREA. MODELS HAVE PUSHED THE HEAVY RAIN AXIS BACK TO THE EAST. ONLY PIKE AND SULLIVAN ARE FORECASTED TO GET BASIN AVERAGE AMOUNTS OVER 2 INCHES. DO NOT WANT TO CHANGE AGAIN SINCE ANOTHER SHIFT BACK TO THE WEST IS POSSIBLE. VERY SHARP GRADIENT BETWEEN LESS THAN 1 INCH AND OVER 3 INCHES. WITH AMPLE TROPICAL MOISTURE AND PWATS OVER 2 INCHES WITH WARM CLOUD DEPTHS TO 14K FT RAINFALL RATES WILL BE OVER 1 INCH AN HOUR. RIGHT REAR QUAD OF UL JET WILL ALSO HELP WITH DEEP LIFT. MODELS IN AGREEMENT OF PLACEMENT OF SW TO NE HEAVY RAIN AXIS ALONG SE CWA BORDER. WITH THE DRY GROUND DUE TO THE LACK OF RAIN SO FAR THIS MONTH ANY FLOODING WILL BE THIS AFTERNOON ON. RIVERS ARE AT SEASONALLY LOW VALUES. IT WILL TAKE OVER 3 INCHES FOR EVEN THE HEADWATERS TO FLOOD. BIGGEST FLOOD THREAT WILL BE FLASH FLOODING OF CREEKS...SMALLER STREAMS...AND URBAN AREAS. THE MAIN STEM OF THE DELAWARE WILL SHOW SIGNIFICANT RISES BUT REMAIN WELL BELOW FLOOD STAGE. THE NYC RESERVOIRS WILL HOLD ALL THE RAIN. WITH HEAVY RAIN AT THE TIME OF THE BEST LL JET DO NOT SEE MUCH WIDESPREAD DOWNWARD TRANSLATION. HIGHEST ELEVATIONS IN THE POCONOS CLOSEST TO THE TRACK OF HANNA COULD SEE SOME GUSTS INTO THE 30S FOR A BRIEF TIME AROUND 00Z. STORM TRACK WILL BE EAST OF CWA WITH FORWARD ACCELERATION. HIGHER WINDS WILL HAVE TROUBLE GETTING ONTO THE BACK SIDE OF THE STORM THIS FAR INLAND. PCPN SHUD CLR OUT LATE SAT NIGHT/EARLY SUN MORNING...LVG CLRNG SKIES AND ABOVE NORMAL TEMPS AS WEAK HIGH PRESSURE BUILDS IN. A COLD FRONT APPROACHES FROM THE WEST MONDAY AFTERNOON AND NIGHT BUT LITTLE FORCING GETS INTO THE CWA UNTIL TUESDAY. HAVE CHC POPS MOSTLY FOR THE NW HALF OF THE CWA. A SFC WAVE COULD FORM AS A STRONG VORT WAVES MOVES EAST WITH A UL TROF. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... SOME LINGERING PRECIP TUESDAY EVENING IN THE EAST AS COLD FRONT EXITS. WEDNESDAY AND THURSDAY LOOK LIKE A NICE COUPLE OF DAYS AS SFC HIGH MOVES ACROSS AND EAST OF THE REGION. MOISTURE THEN INCREASES THURSDAY NIGHT INTO FRIDAY AS ANOTHER FRONT PUSHES EAST. LOOKS LIKE WE THEN DRY OUT AGAIN AT THE END OF THE PERIOD WITH WEAK HIGH PRESSURE IN PLACE. TEMPS MAY BE A BIT BELOW SEASONAL AVERAGES BEHIND THE FRONT WEDNESDAY, BUT OTHERWISE LOOK TO BE NOT TOO FAR FROM NORMAL FOR MUCH OF THE PERIOD. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... STEADY RAIN FROM HANNA MAINLY FROM AN AVP TO BGM LINE SOUTHEAST...PRODUCING MAINLY MVFR CONDITIONS IN MODERATE RAIN. TO THE WEST OF THERE, SCATTERED SHOWERS WITH VFR TO OCCASIONAL MVFR CEILINGS. THE STEADY RAIN WILL CONTINUE THRU THE AFTERNOON INTO EARLY EVENING BEFORE PULLING EAST AND OUT OF THE AREA. EXPECT SOME LOWER CEILINGS IN THE MVFR RANGE WITH LIGHT FOG THRU THE EVENING AFTER PRECIP ENDS BEFORE GRADUAL IMPROVEMENT OVERNIGHT. MAINLY SOUTHEAST WINDS 5-10 KTS OR LESS THIS AFTN BECOMING N/NW TWD LATE AFTN/EVENING AND OVERNIGHT. OUTLOOK... SUNDAY TO MONDAY...VFR. SOME EARLY MORNING RESTRICTIONS IN FOG MOST LIKELY AT ELM. OTHER LOCATIONS COULD FALL TO MVFR VSBYS DUE TO WET GROUND AND GOOD RADIATIONAL COOLING. MONDAY NIGHT TO TUESDAY...NEXT FRONT APPCHS LATE MONDAY NIGHT WITH MVFR RESTRICTIONS IN SHOWERS AND POSSIBLY THUNDER ALONG BNDRY TUESDAY. WEDNESDAY TO THURSDAY...VFR. RESTRICTIONS PSBL IN MORNING FOG ESPECIALLY AT ELMIRA. && .EQUIPMENT... THANKS TO A TREMENDOUSLY DEDICATED TEAM OF ELECTRONICS EXPERTS WORKING LONG HOURS...THE KBGM WSR- 88D BEGAN SPINNING AGAIN AROUND MIDNIGHT LAST NIGHT. THIS WAS DONE IN RECORD TIME OF JUST UNDER FOUR DAYS WITH A TROPICAL STORM LOOMING. ALL USERS SHOULD STILL USE CAUTION WHEN USING PCPN PRODUCTS...AS IT WILL NOT CAPTURE THE STORM TOTAL PCPN AFTER BEING DOWN FOR SEVERAL HRS THIS MRNG. PLEASE REFER TO SURROUNDING RADARS (KENX...KTYX...KBUF...KDIX...KOKX AND KCCX) FOR THE MOST UP TO DATE IMAGES AND ESTIMATED PCPN AMOUNTS. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...FLOOD WATCH THROUGH SUNDAY MORNING FOR PAZ039-040-043-044-047- 048-072. NY...FLOOD WATCH THROUGH SUNDAY MORNING FOR NYZ057-062. && $$ SYNOPSIS...TAC NEAR TERM...PVB/TAC SHORT TERM...PVB/TAC LONG TERM...JML AVIATION...JML EQUIPMENT... ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 751 PM EDT SAT SEP 6 2008 .SYNOPSIS... HIGH PRESSURE WILL GRADUALLY BUILD INTO THE AREA THROUGH MONDAY. A COLD FRONT WILL MOVE INTO THE AREA BY WEDNESDAY...AND STALL OUT TO OUR SOUTH THROUGH THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... AS OF 3 PM SATURDAY...HANNA CONTINUES TO RACE OFF TO THE NORTH NORTHEAST WELL OUT OF OUR LOCAL AREA. LATEST WATER VAPOR SHOWING BRUNT OF MOISTURE ASSOCIATED WITH HANNA LIFTING OFF TO THE NORTH. MOISTURE PROFILES SHOWING PLENTY OF DRY AIR OVERNIGHT TONIGHT WITH LOW LEVEL MOISTURE CONCENTRATED NEAR THE SURFACE TOWARD MORNING. HAVE SEEM SOME CU DEVELOPMENT MAINLY ACROSS NC COUNTIES. EXPECT TO SEE SOME FOG ACROSS THE AREA IN THE EARLY MORNING HOURS...ESPECIALLY WHERE MOST OF THE RAIN FELL FROM HANNA AND WHERE CLOUDS WERE SLOWER TO DISSIPATE THIS AFTN. OTHERWISE WILL MAINTAIN A DECREASING W TO SW FLOW FROM THE SURFACE UP THROUGH H30. RUC AND LOCAL SOUNDINGS SHOWED CLOSE TO 2.5 INCHES OF PCP WATER THIS MORNING DECREASING TO AROUND 2 INCHES THIS AFTERNOON. PCP WATER VALUES SHOULD BE DOWN TO LESS THAN 1.5 INCHES BY MORNING. OVERALL EXPECT A QUIET NIGHT AS SKIES CLEAR IN THE SUBSIDENCE BEHIND HANNA. TEMPS SHOULD DECREASE TO AROUND 70 DEGREES TONIGHT REMAINING SLIGHTLY ABOVE NORMAL. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... AS OF 3 PM SATURDAY...500MB RIDGE WILL EXTEND INTO THE AREA THROUGH TUESDAY. AT THE SURFACE...A WEAK SURFACE TROUGH WILL GIVE WAY TO BUILDING HIGH PRESSURE WHICH WILL DEVELOP VIA UPPER LEVEL CONVERGENCE IN THE MIDWEST. THIS HIGH WILL MOVE OFF THE COAST MONDAY AND EXTEND INTO THE AREA THROUGH TUESDAY MORNING. FOR SENSIBLE WEATHER...BACK TO THE SUMMER GRIND WITH HOT AND HUMID CONDITIONS AND THE STANDARD CHANCE OF CONVECTION ALONG THE SEA BREEZE. WILL ONLY USE SLIGHT CHANCE AS SOUNDINGS SHOW PRECIPITABLE WATERS ARE NOT OVERLY IMPRESSIVE WITH AROUND 1.60 INCHES BOTH DAYS. SPEAKING OF GETTING BACK TO THE SAME OLD ROUTINE...THE MAV NUMBERS ARE IN MID SEASON FORM SHOWING THE WARM BIAS FOR DAYTIME HIGHS WHEN COMPARING GUIDANCE. WILL LEAN TOWARD THE COOLER MET NUMBERS FOR HIGHS AND A BLEND FOR LOWS. STILL LOOKING AT READINGS THREE TO FIVE DEGREES ABOVE NORMAL ACROSS THE BOARD. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 3 PM SATURDAY...WEST ATLANTIC HIGH PRESSURE WILL LOSE ITS INFLUENCE OVER THE REGION TUES WHILE COLD FRONT APPROACHES FROM THE NW. THIS BOUNDARY WILL DROP INTO THE AREA BY DAYBREAK WED. SOUTHEAST FLOW AHEAD OF THIS BOUNDARY WILL BRING IN ATLANTIC MOISTURE AND PW SHOULD RISE TO ABOUT 2.0 INCHES WHILE IKE KEEPS GOMEX MOISTURE FROM ADVECTING NORTHWARD. SHOWER/THUNDERSTORM COVERAGE SHOULD WARRANT LOW CHC POPS AND HIGHS WILL RANGE FROM THE MID 80S COAST TO UPPER 80S INLAND. BOUNDARY WILL STALL VERY NEAR/JUST SOUTH OF THE AREA WED...SHAVING ABOUT A CATEGORY OFF OF HIGH TEMPS. THE H8 RIDGE AXIS WILL REMAIN TO OUR NORTH HOWEVER AND SOUTHEASTERLY FLOW SHOULD CONTINUE AT THIS LEVEL POSSIBLY LEADING TO SOME OVERRUNNING PRECIP. WILL CONTINUE TO CARRY 40-ISH POPS...A BIT BELOW THE 60S THAT GFS IS SHOWING. EXACT POSITION/SIZE/STRENGTH OF IKE LIKELY COULD BE A PLAYER AS GFS IS SHOWING ENHANCED LL FLOW LOCALLY AS A RESULT OF THE STORM. THE FRONT WILL REMAIN OFF TO THE SOUTH FRIDAY AND SATURDAY...PROBABLY IN A WEAKENING STATE. VERY LOW END CHANCE POPS STILL SEEM WARRANTED AS THE LOW LEVEL FLOW ABOVE THE SURFACE AIRMASS WILL REMAIN SOUTHERLY. GRANTED...SOME GRIDSCALE FEEDBACK IN THE GFS HAS MADE THIS DIFFICULT TO DIAGNOSE FOR CERTAIN. ANOTHER COLD FRONT MAY BE APPROACHING FROM THE NORTHWEST AGAIN BY SATURDAY...POSSIBLY TO BE INTERACTED WITH BY IKE SOON THEREAFTER. && .AVIATION /0Z SUNDAY THROUGH FRIDAY/... NO MAJOR CHANGES TO THE PREVIOUS SET OF TAFS. I ADDED A TEMPO GROUP FOR IFR VISIBILITIES AT THE INLAND COUNTIES. CLEAR SKIES...LIGHT WINDS...AND MOIST SOILS SHOULD ALLOW FOR FOG TO DEVELOP OVERNIGHT. MVFR VISIBILITIES CAN BE EXPECTED AFTER 08Z A GOOD CHANCE OF IFR AT LBT AND FLO. VFR EXPECTED AFTER 13Z WITH LIGHT NORTHEAST WINDS. WINDS BECOME SOUTHEAST AT THE COASTAL TERMINALS AFTER 16Z SUNDAY AND BECOME A BIT BREEZY. OUTLOOK THROUGH TUESDAY...CHANCE IFR VISIBILITIES SUNDAY AND MONDAY MORNINGS. ISOLATED THUNDERSTORMS MONDAY AND TUESDAY. SCATTERED THUNDERSTORMS WEDNESDAY AND THURSDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM SATURDAY...HANNA CONTINUES TO MOVE OFF TO THE NORTH WITH AN OFFSHORE FLOW IN ITS WAKE. A SMALL CRAFT ADVISORY HOLDS FOR ALL COASTAL WATERS THIS AFTN. THIS IS HELPING TO PUSH DOWN THE SEAS WHICH WERE CURRENTLY RANGING FROM 5 TO 9 FT ACROSS OUR LOCAL WATERS. THIS SEEMS VERY MUCH IN LINE WITH LATEST WNA MODEL DATA WHICH SHOWS SEAS DECREASING TO UNDER SCA CRITERIA BY THIS EVENING IN SOUTHERN WATERS AND AFTER MIDNIGHT IN THE NORTHERN WATERS. THEREFORE ADJUSTED HAZARD GRIDS ACCORDINGLY. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...AS OF 3 PM SATURDAY...A VERY WEAK AND POORLY DEFINED SURFACE PRESSURE PATTERN SUNDAY WILL EVOLVE INTO A BETTER DEFINED EASTERLY FLOW MONDAY AS SURFACE HIGH PRESSURE ORGANIZES OVER THE MID ATLANTIC AND MOVES OFF TO THE EAST. WINDS WILL BACK FROM A SOUTHERLY DIRECTION SUNDAY TO EASTERLY MONDAY. MAGNITUDES WILL REMAIN WEAK...MOSTLY AT OR BELOW 10 KNOTS. SEAS WILL REMAIN ON THE CUSP OF FLAG CRITERIA AS THE SWELL FROM IKE CONTINUES TO MOVE ACROSS. HIGHEST SEAS WILL BE OUTER WATERS...WITH FIVE FEET...GETTING WORKED OVER TO 3-4 FEET CLOSER TO SHORE. LONG TERM /TUESDAY THROUGH THURSDAY/... AS OF 3 PM SATURDAY...LONG SOUTHEASTERLY FETCH ON TUESDAY WILL BRING A 3 TO 4 FT WIND WAVE ALONG WITH SOME 4 FT SWELLS FROM IKE. A COLD FRONT WILL APPROACH FROM THE NORTHWEST TUESDAY NIGHT AND SHOULD BRING A VEER TO OFFSHORE BY WED. THIS BOUNDARY WILL STALL VERY CLOSE TO OR JUST SOUTH OF THE WATERS SO THERES A LITTLE UNCERTAINTY IN THE FORECAST...MAINLY WITH RESPECT TO WINDS THROUGH THE PD. NOW IT APPEARS THAT WINDS WILL REMAIN ONSHORE BEHIND THE BOUNDARY AND FAIRLY LIGHT...THE ABATING IKE SWELLS WILL STILL BE PRESENT HOWEVER. && .RIP CURRENTS... SOME LEFTOVER SWELL FROM HANNA ALONG WITH AN INCREASINGLY LONG PERIOD SWELL FROM HURRICANE IKE WILL PRODUCE A HIGH RISK FOR RIP CURRENTS ON SUNDAY. THE HURRICANE VERSION OF WAVEWATCH SHOWS TWO DISTINCT SWELLS FROM HANNA...BOTH OVER 11 SECONDS FOR THE PERIOD. WHILE THE THREAT FOR RIP CURRENTS IS HIGH AT ALL AREA BEACHES...THE HIGHEST RISK WILL BE FOR THE BEACHES OF PENDER AND NEW HANOVER COUNTIES IN NC...AND THE BEACHES OF GEORGETOWN AND SOUTHERN HORRY COUNTIES IN SC DUE TO THE SWELL DIRECTION FROM THE SOUTHEAST. SWELLS FROM IKE WILL KEEP AN INCREASED THREAT FOR RIP CURRENTS THROUGH EARLY NEXT WEEK. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS AFTERNOON FOR AMZ254- 256. SMALL CRAFT ADVISORY UNTIL 6 AM EDT SUNDAY FOR AMZ250-252. && $$ SYNOPSIS...SHK NEAR TERM...RGZ SHORT TERM...SHK LONG TERM...MBB AVIATION...MRR/HEDEN RIP CURRENTS...HEDEN nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 856 PM CDT SAT SEP 6 2008 .DISCUSSION... WE WILL MAKE SOME MINOR ADJUSTMENTS TO TONIGHT/S FCST...MAINLY TO TIDY UP POPS AND SKY NOW THAT OBS MAKE IT MORE OBVIOUS THAT MUCH OF THE CONVECTION IS DIURNALLY-INDUCED AND THUS WILL NOT SURVIVE THE NIGHT. THE MAIN EXCEPTION WILL BE WITH THE BATCH OF -SHRA NOW ENTERING SE ND...WHICH SHOULD LAST LONGER /DESPITE ITS CONVECTIVE ORIGINS/ GIVEN MODERATE 500-300 HPA Q-VECTOR CONVERGENCE PER THE 18Z NAM/GFS. OUR CHANCE POPS WILL FOLLOW THIS UPWARD MOTION INTO NW MN 05-09Z. MODIFYING SFC TEMPS ON THE 00Z BIS/ABR RAOBS SUGGEST THAT ONCE WE FALL INTO THE MID 50S F /AS MOST SITES ARE NOW/ THE BUOYANCY WILL BE TOO MARGINAL FOR THUNDER SO THIS WILL ALSO BE DROPPED FROM THE DATABASE. FURTHER UPSTREAM...SATELLITE SHOWS A CELLULAR NATURE TO MOST CLOUDS WHICH SUGGESTS AT LEAST PARTIAL CLEARING SHIFTING SE INTO EASTERN ND JUST AS THE 00Z RUC SHOWS. THIS WILL BE TEMPERED SOME BY LOW/MID LVL CAA...WHICH DROPS 850-HPA TEMPS DOWN TO +2 C IN THE NW FA BY 12Z. NOT AN IDEAL RADIATIONAL COOLING SITUATION...BUT EVEN THIS MORNING LANGDON WAS DOWN TO 38 F...SO WE WILL LOWER TEMPS ABOUT 3 F THERE. THE 18Z NAM ACTUALLY DROPS THAT AREA TO 35 F. ONE OTHER ISSUE MAY AGAIN BE PATCHY FOG OR AT LEAST LOWER CIGS...ESPECIALLY WHERE IT RAINED TDY...AND IN NW MN WHERE MOST 12/18Z MODELS AND THE 00Z RUC ALL DEVELOP IFR CIGS 09-12Z. WE WILL NOT ADD ANY FOG AT THIS POINT BUT IT IS SOMETHING TO KEEP AN EYE ON. .AVIATION... SCATTERED -SHRA WILL MOVE EAST AT 20KTS INTO NW MN THRU 06Z... THOUGH IT IS QUESTIONABLE HOW LONG THEY WILL LAST NOW THAT THE SUN HAS SET. MARGINAL MVFR CIGS/VIS COULD ACCOMPANY THIS ACTIVITY. THE LOW CONFIDENCE PART OF THE AVIATION FORECAST IS 08-13Z WHEN IFR OR LOWER CIGS /OR VIS/ ARE POSSIBLE. THIS HAPPENED THE PAST TWO MORNINGS AND MODEL GUIDANCE SUGGESTS IT WILL AGAIN...AT LEAST AT KTVF/KBJI. THIS IS HINTED AT IN THE PRESENT TAF SET...BUT UNTIL CONFIDENCE INCREASES THE FORECAST WILL REMAIN SOMEWHAT OPTIMISTIC. && .PREV DISCUSSION... /ISSUED 339 PM CDT SAT SEP 6 2008/ SHORT TERM... MAIN FORECAST CHALLENGE IS PRECIPITATION. WHEN LOOKING AT THE LATEST SURFACE ANALYSIS...AN AREA OF LOW PRESSURE IS CENTERED IN NE MB WITH A WEAK COLD FRONT THAT EXTENDS E MB TO ALONG A ROX TO DTL LINE. WHEN COMPARING THE MODELS...THE MODELS REMAIN IN PRETTY GOOD AGREEMENT FOR THE SHORT TERM...SO ENDED UP USING MODEL COMPROMISE FOR THE FORECAST. BLENDED THE GFS AND NAM FOR POPS AS THEY DIFFER ON WHAT PART OF THE CWFA WILL BE MOST AFFECTED BY TONIGHT`S TROF PASSAGE. AS FAR AS TEMPS...WITH ADJMAVBC STILL DOING PRETTY WELL...USED IT AS A STARTING POINT AND THEN ADJUSTED FROM THERE. KMVX CURRENTLY SHOWS TWO AREAS OF CONVECTION...ONE IN THE E AND ANOTHER IN THE W. E PCPN IS AHEAD AND ALONG OF SURFACE FRONT AND W PCPN IS ASSOCIATED WITH PUSH OF NEXT WAVE AS SEEN ON WV IN ASSOCIATION WITH THE 500MB TROF. 500MB TROF IS EXPECTED MOVE THROUGH THE N PLAINS TONIGHT AND SUN...SO KEPT PCPN IN THE FORECAST. MODELS DO KEEP SHOWALTERS AT OR BELOW ZERO OVER PARTS OF THE AREA UNTIL 06Z TONIGHT. WITH OCCASIONAL LTG FOUND IN STORMS THAT HAVE DEVELOPED... KEPT THUNDER MENTION IN FOR THIS EVENING AND TRANSITIONED TO SHRA AFTER 06Z. FOR SUN NIGHT INTO TUE...SURFACE HIGH PRESSURE DOMINATES THE WEATHER...SO KEPT THE FORECAST DRY. THERE IS A ANOTHER 500MB TROF THAT MOVES THROUGH ON MON NIGHT...BUT WITH MINIMAL UVV AT 700MB...850MB Q-VECTOR DIVERGENCE INDICATED AND ALSO STABILITY INDICES ABOVE ZERO...BELIEVE THAT WILL ONLY SEE CLOUDS FROM THIS TROF PASSAGE AT THIS TIME. LONG TERM (TUE THROUGH SAT)... MEDIUM-RANGE MODELS CONTINUE TO DIFFER WITH STRENGTH AND TIMING OF NEXT PACIFIC SHORT WAVE. 00 UTC CANADIAN AND 12 UTC ECMWF SOLUTIONS BRIEFLY CUT-OFF WEAK 500 HPA LOW OVER THE CENTRAL ROCKIES THU MORNING BEFORE EJECTING PRIMARY ENERGY EASTWARD...WHEREAS GFS IS STRONGER AND MUCH MORE PROGRESSIVE. CURRENT FORECAST PRIMARILY FOLLOWS HPC GUIDANCE...WHICH FAVORED FASTER GFS. MODEL CONSENSUS SHOWS BEST CHANCE FOR MEASURABLE PRECIPITATION WED AND THU OUT AHEAD OF PRIMARY MID-LEVEL WAVE...ALTHOUGH THIS TIME FRAME MAY BE PUSHED LATER OR EXTENDED IF SLOWER CANADIAN/ECMWF SOLUTIONS BECOME REALITY. EITHER WAY...TEMPERATURES WILL CONTINUE TO TREND BELOW SEASONAL NORMALS THROUGH NEXT WEEK. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ SCHULTZ/NG/ROGERS nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TULSA OK 1046 AM CDT SAT SEP 6 2008 .DISCUSSION... RAIN AND THUNDERSTORMS ACROSS NORTHEAST OKLAHOMA CONTINUE TO SHOW AN OVERALL DECREASING TREND THIS MORNING WITH A WEAKENING/VEERING LOW LEVEL JET THAT WILL CONTINUE TO ADD TO THEIR DEMISE. HAVE TRIMMED BACK MORNING POPS ACROSS FAR WESTERN SECTIONS AS WELL AS MOST OF NORTHWEST ARKANSAS AS A RESULT. CHANCE OF ADDITIONAL DEVELOPMENT DURING THE AFTERNOON APPEARS SLIM AS A STOUT CAP LOOKS TO BE IN PLACE ALONG AND SOUTH OF BOUNDARY LEFT BY MORNING STORMS. 14Z RUC DOES INDICATE IN A RELATIVE WEAKNESS IN CAP ACROSS OSAGE/PAWNEE COUNTIES THIS AFTERNOON AND WILL LEAVE LOW PROBABILITY OF POPS THROUGH THE AFTERNOON TO ACCOUNT FOR THIS AS WELL AS LINGERING IMPACT FROM ONGOING ACTIVITY FARTHER EAST. ENOUGH BREAKS IN CLOUDS SHOULD ALLOW TEMPS TO GET REASONABLY CLOSE TO FORECAST HIGHS SO WILL NOT MAKE CHANGES AT THIS TIME. ANOTHER FORECAST UPDATE WILL BE ISSUED AROUND 11 AM. && .PREV DISCUSSION... /ISSUED 637 AM CDT SAT SEP 6 2008/ DISCUSSION... AVIATION... LOCALIZED DENSE FOG AT KFYV WILL BURN OFF BY AROUND 14Z. A COMPLEX OF SHOWERS AND THUNDERSTORMS IS SLOWLY WEAKENING AS IT MOVES INTO NORTHEAST OKLAHOMA. INCLUDED A TEMPO GROUP FOR THUNDER AT KTUL AND KRVS FOR A FEW HOURS THIS MORNING BUT EXPECT THE BULK OF THE PRECIPITATION TO DISSIPATE BEFORE IT REACHES KXNA AND KFYV. ANOTHER THUNDERSTORM COMPLEX IS EXPECTED TO DEVELOP OVERNIGHT TONIGHT AND AFFECT THE NORTHEAST OKLAHOMA AND NORTHWEST ARKANSAS TAF SITES AFTER 05Z. PREV DISCUSSION... /ISSUED 441 AM CDT SAT SEP 6 2008/ DISCUSSION... INITIAL WAVE ROTATING THROUGH WIDE BODIED TROUGH WILL BRING THUNDER..AND SHOWERS TO NORTHERN TIER OF ZONES NORTHEAST OK EARLY THIS MORNING. LOOKS AS IF CITY OF TULSA WILL BE NEAR SOUTHERN FRINGE OF THAT ACTION. MARGINAL POPS RETAINED FOR THE AFTERNOON PERIOD. AN INSTANT REPLAY POSSIBILITY AGAIN TONIGHT... WITH BETTER THAN EVEN CHANCE OF THUNDER AGAIN NEAR / ON OKLAHOMA / KANSAS BORDER. SUNDAY AND EARLY MONDAY BEST LIFT NORTH WHEN H5 MB FLOW BACKS SOME. STILL LOW POPS NORTHERN TIER ZONES. NORTHWEST FLOW DRIVES COOL FRONT BOUNDARY THROUGH MONDAY NIGHT. MORE CHANCE OF PRECIP BOTH MONDAY NIGHT AND TUESDAY. BOTH..ECMWF / GFS BRING TROPICAL MISERY INTO THE THE GULF BY MIDWEEK. && .PRELIMINARY POINT TEMPS/POPS... TUL 80 64 84 66 / 40 40 10 10 FSM 84 62 88 65 / 10 20 10 10 MLC 85 65 89 67 / 10 10 0 0 BVO 75 61 82 64 / 70 60 20 30 FYV 78 60 83 62 / 20 30 20 10 BYV 76 61 81 61 / 20 40 30 10 MKO 82 63 86 66 / 10 30 20 10 MIO 76 61 81 64 / 70 60 20 30 F10 83 64 87 67 / 10 20 10 10 HHW 88 64 90 68 / 10 10 0 10 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ SHORT TERM...14 LONG TERM....07 ok AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 344 AM EDT SAT SEP 6 2008 .SYNOPSIS... TROPICAL STORM HANNA WILL MOVE NORTH ALONG THE ATLANTIC COAST THROUGH EARLY SUNDAY...BRINGING RAIN TO MUCH OF CENTRAL PENNSYLVANIA. HEAVY RAIN FROM HANNA SHOULD BE CONFINED TO PARTS OF THE LOWER AND MIDDLE SUSQUEHANNA VALLEYS. A RETURN TO DRY CONDITIONS IS EXPECTED SUNDAY INTO MONDAY...AS HIGH PRESSURE BUILDS EASTWARD. A COLD FRONT FROM THE PLAINS WILL BRING A CHANCE OF SHOWERS AND THUNDERSTORMS TO THE AREA ON TUESDAY. && .NEAR TERM /UNTIL 11 AM THIS MORNING/... TWO AREAS OF RAINFALL TO DEAL WITH TODAY. THE FIRST IS OCCURRING WELL OUT AHEAD OF HANNA WHICH MOVES ONSHORE NEAR MYRTLE BEACH SC A FEW HOURS AGO...AND THIS RAIN EXTENDS IN A BAND FROM THE WV PANHANDLE TO THE ENDLESS MOUNTAINS OF NORTHEAST PENNSYLVANIA. SHORT TERM GUIDANCE AND MESOSCALE MODELS PIVOT THIS BAND THROUGHOUT THE MORNING FROM A SW-NE ORIENTATION TO MORE OF A NNE TO SSW FASHION...WHICH WILL SLIGHTLY INCREASE RAINFALL AMOUNTS IN THESE AREAS BY UP TO .25". MOST OF THIS INITIAL RAIN IS LIGHT HOWEVER... AND CERTAINLY WELCOME ANYWHERE IT FALLS GIVEN THE RECENT EXTENDED DRY SPELL. TRACK OF HANNA STILL EXPECTED UP THE NEW JERSEY COAST...CONFINING MOST OF THE HEAVY RAINS TO THE COASTAL PLAIN...WITH A TIGHT GRADIENT TOWARD LESSER AMOUNTS TO THE WEST. CHANGED QPF VERY LITTLE OTHER THAN TO INCREASE AMOUNTS BY .05 TO .15" OVER CENTRAL/ WEST CENTRAL PORTIONS WITH THE INITIAL "PRE" RAINFALL ASSOCIATED WITH THE INVERTED SFC TROF AND DEEP EASTERLY FLOW NORTH OF HANNA`S CIRCULATION. PREVIOUS QPF OVERALL CHANGED VERY LITTLE WITH AMOUNTS IN EXCESS OF 4" POSSIBLE OVER SERN COUNTIES...TAPERING TO LESS THAN .25" LOCALLY. NO CHANGE IN GOING HEADLINES...FLOOD WATCH AREAS CONTINUE TO MATCH UP WELL WITH EXPECTED QPF. WIND ADVISORY MAY BE DIFFICULT TO REACH BUT IT WILL BECOME BREEZY ACROSS MY SOUTHEAST COUNTIES AND MAY SEE SOME GUSTS IN ADV RANGE. DAY SHIFT MAY NEED TO DROP THIS ONCE THE PICTURE STARTS TO CLEAR ON EXACTLY WHERE HANNA WILL GO. && .SHORT TERM /11 AM THIS MORNING THROUGH 6 PM SUNDAY/... THERE WILL BE A LULL BETWEEN THE INITIAL BANDOF SHOWERS THIS MORNING TO THE NORTH AND THE APPROACHING HANNA CIRCULATION WHICH WILL BRING THE BULK OF THE HEAVY RAINFALL THIS AFTERNOON AND TONIGHT OVER THE LOWER TO MIDDLE SUSQUEHANNA RIVER VALLEY. SHOWERS WITH ISOLATED THUNDERSTORMS WILL BECOME MORE PREVALENT DURING THE AFTERNOON ACROSS MUCH OF CENTRAL PA...THOUGH THE FARTHER NW ONE GOES THE LESS RAIN IS EXPECTED. WILL CONTINUE FLOOD WATCH INTO SUNDAY AFTN ATTM...AS RAINFALL TAKES A WHILE TO REACH TRIBS AND RIVERS AND SHORT RANGE. RAIN SHOULD TAPER OFF LATE SATURDAY EVENING AS THE STORM PULLS AWAY. SUNDAY LOOKS PRETTY NICE WITH MORE - SEASONABLE TEMPS THAN WE HAVE HAD RECENTLY. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... AFTER HANNA...HIGH PRESSURE BRINGS A RETURN TO DRY CONDITIONS TO THE AREA FOR MOST OF SUNDAY INTO MONDAY. A COLD FRONT BRINGS A CHANCE OF SHOWERS AND STORMS TO THE AREA LATE MONDAY INTO TUESDAY. THE 06Z AND 18Z RUNS OF THE GFS OFTEN OVERDO SYSTEMS. IN THIS CASE...DYNAMICS FCST TO LAG THE FRONT ANYWAY...SO I AM NOT REAL CONCERN ABOUT WIDESPREAD STRONG TO SEVERE STORMS. DID TAPER MENTION OF SHOWERS AND STORMS OUT OF TUE EVENING FOR WESTERN ZONES...AS SYSTEM IS MOVING RIGHT ALONG. SLIGHTLY COOLER AIR FOR WED INTO THU WILL FOLLOW THE FRONT. WED AND THU SHOULD BE DRY. A WARM UP IN STORE FOR THE AREA AFTER THIS. DID PUT CHC OF SHOWERS AND STORMS IN FOR FRIDAY...AS NEXT FRONT NEARS THE AREA. && .AVIATION /07Z SATURDAY THROUGH WEDNESDAY/... DETERIORATING FLYING CONDS THIS MORNING SPREADING FROM SOUTHEAST TO NORTHWEST AS TROPICAL STORM HANNA RIDES UP THE EAST COAST. FIRST BAND OF RAIN ALREADY ACROSS SOUTHERN PA...ACCOMPANIED BY IFR CIGS. LATEST RUC13 SUGGESTS IFR CIGS WILL SPREAD NW EARLY THIS MORNING...COVERING NEARLY ALL OF CENTRAL PA BY DAWN. IT STILL LOOKS AS THOUGH THE HEAVIEST RAIN WILL FALL OVR SOUTHEAST PA DURING THIS AFTN AS HANNA MAKES IT/S CLOSEST PASS ACROSS THE DELMARVA PENINSULA. HOWEVER...MVFR TO IFR CIGS SHOULD PREVAIL ACROSS ALL OF CENTRAL PA THRU AT LEAST EARLY AFTN AS MOIST LOW LVL SERLY FLOW ASCENDS THE HIGHER TERRAIN OF CENTRAL PA. IMPROVING CONDS WILL DEVELOP FROM NW TO SE DURING THE AFTN AND EVENING HOURS...AS A COLD FRONT PUSHES THRU THE AREA AND WINDS SHIFT TO THE NW. LATEST MODEL GUIDANCE SUGGESTS CORE OF STRONG WINDS FROM HANNA WILL REMAIN EAST OF THE REGION. HOWEVER...AS HANNA PULLS AWAY THIS EVENING...SFC WNDS LIKELY TO INCREASE TO BTWN 10-15KTS AS THEY BACK TO THE NW. RESIDUAL LL MOISTURE ASCENDING THE ALLEGHENIES COULD RESULT IN AREAS OF IFR/MVFR CIGS AT BFD AND JST TONIGHT. OTHERWISE...VFR CONDITIONS EXPECTED TONIGHT THRU MONDAY AS A RIDGE OF HIGH PRESSURE BUILDS IN. A COLD FRONT WILL LIKELY PASS THRU THE AREA MONDAY NIGHT OR TUESDAY...BRINGING WITH IT SCATTERED SHOWERS AND THUNDERSTORMS. HI PRESSURE IS EXPECTED TO BUILD IN FOR MIDWEEK...ACCOMPANIED BY GOOD FLYING CONDS. && .HYDROLOGY... SIGNIFICANT RAINFALL AMOUNTS ARE EXPECTED OVER EASTERN PARTS OF CENTRAL PA...AT LEAST IN THE ONE TO THREE INCH RAIN OVER PARTS OF THE LOWER SUSQ VALLEY. WILL MAINTAIN PREVIOUSLY ISSUED FLOOD WATCH FOR FIVE SERN MOST COUNTIES IN OUR CWA FOR THIS MORNING INTO SUNDAY AFTERNOON...AS RAINFALL TAKES A WHILE TO REACH TRIBS AND RIVERS. EVEN WITH VERY HIGH FFG AND HEADWATER VALUES THANKS TO THE RECENT VERY DRY WEATHER...MAGNITUDE OF THE EXPECTED RAINFALL WILL LIKELY CREATE AT LEAST SOME MINOR FLOODING PROBLEMS LATE TONIGHT INTO SUNDAY...PARTICULARLY IN AREAS WHICH RECEIVE 3 INCHES OR MORE. && .CTP WATCHES/WARNINGS/ADVISORIES... FLOOD WATCH FROM 8 AM EDT THIS MORNING THROUGH SUNDAY AFTERNOON FOR PAZ057>059-065-066. WIND ADVISORY FROM NOON TODAY TO MIDNIGHT EDT TONIGHT FOR PAZ057>059-064>066. && $$ SYNOPSIS...LACORTE/DEVOIR NEAR TERM...LACORTE/DEVOIR SHORT TERM...DEVOIR LONG TERM...MARTIN AVIATION...FITZGERALD HYDROLOGY...DEVOIR pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPOKANE WA 450 AM PDT SAT SEP 6 2008 .SYNOPSIS... A COOL NORTHWEST FLOW WILL CONTINUE ACROSS THE REGION INTO THE WEEKEND. ISOLATED SHOWERS WILL BE POSSIBLE OVER THE MOUNTAINS THROUGH SATURDAY. LOOK FOR A WARMING TREND INTO EARLY NEXT WEEK...BEFORE THE NEXT SYSTEM SWINGS IN TOWARD MID WEEK. && .DISCUSSION... ISSUED 235 AM TODAY AND TONIGHT...THE LOW AMPLITUDE RIDGE/TROUGH PATTERN OVER NORTH AMERICA WILL CONTINUE THROUGH THE WEEKEND. THE RIDGE OVER THE EASTERN PACIFIC AND DOWNSTREAM TROUGH OVER THE UPPER MIDWEST HAS MOVED LITTLE DURING THE LAST WEEK. THE RESULTING NORTHWESTERLY FLOW HAS KEPT EASTERN WASHINGTON AND NORTHERN IDAHO RELATIVELY COOL. A BAND OF 700MB MOISTURE MOVED THROUGH NORTHEAST WASHINGTON LAST NIGHT BRINGING LIGHT RAIN SHOWERS TO SPOKANE...THE NORTHERN PALOUSE...AND SOUTHERN SHOSHONE COUNTY. THE RUC AS OF 09Z AND THE 00Z NAM SHOW THIS RIBBON OF 700MB MOISTURE...AND FORECAST IT TO GRADUALLY SINK TO THE SOUTHEAST BETWEEN 09Z AND 15Z. FOR THIS REASON...PRECIPITATION CHANCES HAVE BEEN INCREASED TO 20-30 PERCENT FOR SOUTHERN SHOSHONE COUNTY THIS MORNING. ONCE THIS BAND OF MOISTURE MOVES OUT OF THE SPOKANE FORECAST AREA...THE BEST CHANCES FOR RAIN THIS AFTERNOON LOOKS TO BE OVER THE MOUNTAINS OF NORTHERN WASHINGTON AND OVER THE PANHANDLE MOUNTAINS. THE MODELS HAVE NOT HANDLED THE MID LEVEL MOISTURE DESCENDING INTO THE REGION IN THE NORTHWEST FLOW...SO IT IS HARD TO PUT PRECIPITATION CHANCES HIGHER THAN 20 PERCENT FOR THE AFTERNOON. FOR TEMPERATURES...HIGHS SHOULD BE CLOSE TO PERSISTENCE THIS AFTERNOON...BUT LOWS WILL LIKELY BE A FEW DEGREES COOLER TONIGHT. THE THICK CLOUDS THAT WE HAVE EXPERIENCED OVERNIGHT...WILL NOT LIKELY BE AROUND TONIGHT TO INHIBIT THE RADIATIONAL COOLING. /GKOCH SUNDAY THROUGH FRIDAY...MODELS STILL IN GOOD AGREEMENT THROUGH THE FORECAST PERIOD. RIDGE AXIS SETS UP ALONG THE BRITISH COLUMBIA COASTLINE SUNDAY. A WEAK WAVE WILL EXIT THE IDAHO PANHANDLE IN THE MORNING AND DRIER AIR WILL MOVE IN BY AFTERNOON. THE RIDGE FLATTENS MONDAY AS THE NEXT WEATHER SYSTEM MOVES INTO NORTHERN BRITISH COLUMBIA. THE GFS CONTINUES TO BE THE STRONGER OF THE MODELS WITH THE TROUGH...AND IT LOOKS AS THOUGH IT HAS CAUGHT UP TIMING-WISE WITH THE ECMWF. TUESDAY CLOUDS WILL INCREASE FROM THE NORTH AND WINDS WILL PICK UP IN THE AFTERNOON...ESPECIALLY IN THE OKANOGAN VALLEY. FOR THE LAST DAY THE GFS HAS NOT BEEN SHOWING ANY PRECIP WITH THIS FRONT. THE ECMWF HAS SHOWN SOME...BUT IT IS VERY LIGHT. DID NOT MAKE ANY CHANGES TO THE PRECIP FOR TUESDAY NIGHT. STILL HAVE SLIGHT CHANCE...EVEN THOUGH THE GFS REMAINS VERY DRY FROM 850-500 MB. THE TROUGH EXITS TO THE EAST BY WEDNESDAY MORNING WITH ANOTHER RIDGE BUILDING IN FOR THE REMAINDER OF THE WORK WEEK. BY FRIDAY MODELS ARE SHOWING 850 MB TEMPERATURES OF NEAR 20C. TEMPERATURES SUNDAY AND MONDAY WILL BE SLIGHTLY ABOVE AVERAGE. TEMPS LOWER TUESDAY AND WEDNESDAY TO NEAR AVERAGE READINGS...AND THEN REBOUND AGAIN TO ABOVE AVERAGE FOR THURSDAY AND FRIDAY. /NISBET && .AVIATION... BANDS OF MID AND HIGH LEVEL CLOUDS WILL MOVE ACROSS EASTERN WASHINGTON AND NORTHERN IDAHO TODAY AND TONIGHT. CLOUD BASES WILL GENERALLY REMAIN ABOVE 6KFT...SO VFR CONDITIONS ARE EXPECTED THROUGH 12Z SUNDAY. SOME WIDELY SCATTERED RAIN SHOWERS WILL BE POSSIBLE THROUGH 06Z...MAINLY OVER THE MOUNTAINS. NO CEILING OR VISIBILITY RESTRICTIONS ARE EXPECTED WITH THESE SHOWERS. /GKOCH && .PRELIMINARY POINT TEMPS/POPS... SPOKANE 73 48 76 48 79 49 / 10 10 0 0 0 0 COEUR D`ALENE 71 46 76 46 78 45 / 10 10 0 0 0 0 PULLMAN 73 44 76 43 79 44 / 10 10 0 0 0 0 LEWISTON 80 54 81 53 85 54 / 10 0 0 0 0 0 COLVILLE 74 43 79 42 81 45 / 10 10 0 0 0 0 SANDPOINT 68 41 72 40 74 43 / 10 10 10 0 0 0 KELLOGG 68 45 72 45 77 48 / 20 20 0 0 0 0 MOSES LAKE 81 51 83 48 85 51 / 0 0 0 0 0 0 WENATCHEE 80 55 81 54 82 57 / 0 0 0 0 0 0 OMAK 80 50 82 47 83 50 / 10 10 0 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...NONE. WA...NONE. && $$ wa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 304 AM CDT SAT SEP 6 2008 .SHORT TERM...TODAY THROUGH MONDAY NIGHT MAIN FORECAST CONCERNS ARE ON PRECIPITATION CHANCES LATE TONIGHT AND SUNDAY AND THEN AGAIN MONDAY AND MONDAY NIGHT. AT 08Z WATER VAPOR IMAGERY SHOWS SHORTWAVE ROTATING THROUGH SOUTHERN WISCONSIN. LIGHT PRECIPITATION ASSOCIATED WITH IT HAD MOVED INTO EASTERN WISCONSIN. INFRARED SATELLITE IMAGERY STILL SHOWING SOME LINGERING STRATUS ACROSS THE FORECAST AREA...BUT AREAS THAT HAVE CLEARED FOG WAS BEGINNING TO FORM. 06.00Z NAM/GFS CONTINUE TO SHOW LONGWAVE TROUGH TO RESIDE ACROSS THE UPPER MISSISSIPPI RIVER VALLEY REGION THROUGH THE PERIOD. DIFFERENCES DO OCCUR WITH TIMING AND STRENGTH OF SHORTWAVES AFFECTING THE AREA. THE FIRST WILL BE LATE TONIGHT AND SUNDAY WITH ANOTHER ONE MONDAY AND MONDAY NIGHT. HAVE USED A BLEND APPROACH IN HANDLING BOTH OF THESE WAVES. IN THE NEAR TERM...SHORTWAVE TO CONTINUE TO MOVE AWAY FROM THE AREA THIS MORNING. LINGERING STRATUS AND FOG WILL DISSIPATE THIS MORNING...BUT RUC AND NAM MODEL SOUNDINGS SHOW CUMULUS TO REDEVELOP BY MIDDAY. WEAK HIGH PRESSURE AT THE SURFACE WILL KEEP THINGS DRY TODAY WITH TEMPERATURES SIMILAR TO YESTERDAY. FIRST SHORTWAVE MOVES THROUGH THE LONGWAVE TROUGH AND APPROACHES THE AREA LATE TONIGHT AND SUNDAY. POTENTIAL VORTICITY ADVECTION ALONG WITH UPPER LEVEL DIVERGENCE DUE TO COUPLED JET WILL ENHANCE LIFT ACROSS THE AREA. ISENTROPIC UPGLIDE ON THE 300K SURFACE REACHES THE WESTERN AREAS LATE TONIGHT AND ACROSS THE REMAINDER OF THE FORECAST AREA ON SUNDAY. WITH CONSISTENT SIGNAL...HAVE RAISED POPS INTO THE LIKELY CATEGORY FOR MOST LOCATIONS...ESPECIALLY ACROSS THE CENTRAL AND NORTHERN SECTIONS. AS WAVE PUSHES EAST SUNDAY NIGHT WILL HOLD ON TO EVENING POPS WITH DRY CONDITIONS AFTER MIDNIGHT. THIS BREAK WILL BE SHORT LIVED AS YET ANOTHER SHORTWAVE HEADS TOWARD THE AREA. GFS FASTER IN TAKING THIS WAVE ACROSS IOWA ON MONDAY...WHILE NAM KEEPS BULK OF LIFT/PRECIPITATION MONDAY NIGHT. WITH WARM FRONT RESIDING WELL TO OUR SOUTH BOTH THE GFS AND NAM SHOWING BAND OF FN CONVERGENCE TO THE NORTH OF THE SURFACE BOUNDARY. THIS FORCING/LIFT WILL HAVE TO BATTLE A SOMEWHAT DRY SURFACE TO 700MB LAYER OVER THE FORECAST AREA THAT MAY INHIBIT THE NORTHERN EXTENT OF THE SATURATION. HAVE CONTINUED POPS IN THE CHANCE CATEGORY BOTH MONDAY AND MONDAY NIGHT WITH THE HIGHER ONES ACROSS THE SOUTHERN ZONES CLOSER TO THE STRONGER FORCING. TEMPERATURES RATHER TRICKY WITH CLOUDS AND PRECIPITATION AROUND THE AREA. WENT NEAR GUIDANCE FOR AFTERNOON HIGHS TODAY THEN BELOW GUIDANCE WITH CLOUDS AND RAIN EXPECTED SUNDAY. SIMILAR TO PREVIOUS GRIDDED FORECAST. .LONG TERM...TUESDAY THROUGH FRIDAY NO CHANGES MADE TO THIS TIME FRAME. BOTH 06.00Z GFS AND ECMWF SHOW GOOD CONSISTENCY THROUGH THE PERIOD. SURFACE HIGH PRESSURE SETTLES OVER THE AREA TUESDAY AND PUSHES EASTWARD BY WEDNESDAY AS RETURN FLOW AHEAD OF THE NEXT SHORTWAVE OVERSPREADS THE AREA. WARM ADVECTION SHOWERS AHEAD OF APPROACHING WAVE ON WEDNESDAY WITH BETTER CHANCES FOR RAIN WEDNESDAY NIGHT AS COLD FRONT MOVES ACROSS THE AREA. SYSTEM LOOKS TO EXIT BY THURSDAY NIGHT WITH DRY WEATHER FOR THE END OF THE WORK WEEK. TEMPERATURES LOOK TO REMAIN BELOW NORMAL THROUGH THE PERIOD...ESPECIALLY WITH AFTERNOON HIGHS. CURRENT GRIDDED DATABASE HAS ALL THIS WELL IN HAND. && .AVIATION...TODAY AND TONIGHT CONCERN THIS MORNING WILL BE FOG POTENTIAL IN WAKE OF DEPARTING SHORTWAVE TROUGH. IFR FOG/STRATUS DEVELOPED AT KRST TAF SITE WITH CLEARING SKIES. EXPECT FOG ALSO TO DEVELOP AT KLSE ONCE MID CLOUD COVER DEPARTS EAST WITHIN THE NEXT HOUR OR SO. FOG/STRATUS WILL LIFT AROUND 15Z ONCE GOOD MIXING OCCURS WITH WESTERLY AIRFLOW. WEAK AREA OF HIGH PRESSURE WILL KEEP THE AREA DRY TODAY. OTHERWISE...COLD AIR ALOFT WILL PRODUCE ENOUGH INSTABILITY FOR SCT-BKN CUMULUS FIELD WITH BASES IN THE 3-4KFT RANGE AFTER 17Z. ANOTHER MID-LEVEL SHORTWAVE TROUGH WILL ROTATE EAST INTO THE UPPER MIDWEST THIS EVENING AND OVERNIGHT FOR A CHANCE OF -SHRA AT THE KRST/KLSE TAF SITES AFTER MIDNIGHT. WILL LIKELY INTRODUCE A VCSH MENTION AT THE KRST/KLSE TAF SITES AFTER 06Z WITH THE 12Z TAF ISSUANCE. OTHERWISE...EXPECTING VFR CONDITIONS OVERNIGHT. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT/LONG TERM...RABERDING AVIATION..........DAS wi