AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BOISE IDAHO 1010 PM MDT WED SEP 8 2004 .DISCUSSION...3Z RUC SHOWS A PAIR OF UPPER JET CORES OVER THE NW U.S. ONE NEAR THE PANHANDLE WHICH HELPED FIRE LATE DAY THUNDERSTORMS /IN ITS LEFT FRONT QUADRANT/ IN THE N...AND ANOTHER CORE EXTENDING ACROSS NV AND UT WHICH BROUGHT MORE STABLE AIR ACROSS SE OREGON TODAY. TIMING DIFFERENCES CONTINUE WITH THE NEXT UPPER WAVE OUT NEAR 140W CROSSING THE GREAT BASIN AND MOST TROUBLING IS THE 12Z ENSEMBLE MEAN BEING DEEPER /WITH LOWER H5 HEIGHTS/ OVER SW IDAHO THROUGH 12Z FRIDAY THAN THE 18Z RUNS AND NOW 00Z RUNS. THE ENSEMBLE MEANS WOULD SUGGEST GOING AWAY FROM THE SLOWER/WARMER ETA BUT WON'T MAKE CHANGES THIS SHIFT. MARGINAL WIND GUSTS AND LOW HUMDITIES TODAY WILL BE SLIGHTLY ENHANCED OVER FWZ408 THURSDAY DUE TO TIGHTER THERMAL GRADIENT BUT DECREASED FROM TODAY BECAUSE THE UPPER JET CORES WILL HAVE MOVED E AND THE NEXT ONE /45-50N AND W OF 130W/ NOT FAR ENOUGH SOUTH FOR AREAS OF G30 SEVERAL HOURS THURSDAY AFTERNOON. && .PREVIOUS DISCUSSION...340 PM MDT WED SEP 8 2004 SHORT TERM...TONIGHT THROUGH SATURDAY. L/WV HIGH PRESSURE RIDGE OVER WESTERN U.S. CONTINUES TO BE FLATTENED BY WEAK EASTERN PACIFIC S/WV TROUGHS MOVING EAST ALONG CANADIAN BORDER. MOISTURE/DYNAMICS ASSOCIATED WITH THESE PASSING S/WVS WILL REMAIN MOSTLY TO NORTH OF CWFA FOR DRY CONDITIONS THROUGH SAT TEMPS SLIGHTLY ABOVE NORMAL. FEW MID AND HIGHER LEVEL CLOUDS WILL MOVE ACROSS NORTHERN ZONES WITH THE PASSING OF EACH S/WV. 12Z GFS PUSHES DRY SURFACE COLD FRONT ASSOCIATED WITH S/WV ON NORTHWEST COAST AT 20Z THROUGH CWFA THU WHILE ETA KEEPS A STRONGER HIGH PRESSURE RIDGE OVER GREAT BASIN AND STALLS FRONTAL BAND ACROSS CENTRAL ID. GFS MOS GUIDANCE 3-7 DEGREES COOLER THAN ETA MOS GUIDANCE FOR THU MAX TEMPS DUE TO THIS FRONTAL BAND PASSAGE. HOWEVER GFS MODEL TREND PAST 3-4 DAYS HAS BEEN TO KEEP FRONTAL BAND TO NORTH OF CWFA AND KEEP WARMER TEMPS THU. HAVE TRENDED THU TEMPS TOWARD WARMER ETA GUIDANCE BUT COOLED NORTHERN ZONES CLOSEST TO BAROCLINIC ZONE. LITTLE CHANGE EXPECTED FRI BEFORE WARMING SAT AS WESTERN HIGH PRESSURE RIDGE BUILDS AND SOUTHWEST FLOW ALOFT DEVELOPS OVER AREA IN RESPONSE TO DEEPENING GULF OF ALASKA TROUGH APPROACHING NORTHWEST COAST. MODEL DIFFERENCES IN S/WV PASSAGE TIMING AND STRENGTH SAT PRODUCES A LOWERED CONFIDENCE LEVEL IN TEMPS. 12Z GFS/ECMWF FASTEST MODELS WITH S/WV PASSAGE PUSHING SURFACE COLD FRONT INTO NORTHEAST ORE LATE SAT AFTERNOON WHILE ETA/ UKMET MODELS SLOWER. HAVE TREND SAT AFTERNOON FORECAST TOWARD STRONGER HIGH PRESSURE OVER WEST WHICH WILL SLOW AND WEAKEN S/WV TREND FOR DRY CONDITIONS OVER CWFA WITH MAX TEMPS WARMEST OF THE WEEK...RANGING FROM 3-7 DEGREES ABOVE NORMAL. .LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY...PATTERN CHANGE IN THE EXTENDED WITH A LONG WAVE TROUGH THAT WILL MOVE IN OVER THE REGION SUNDAY INTO MONDAY. NEAR NORMAL TEMPERATURES ON SUNDAY WITH BELOW NORMAL TEMPERATURES TO FOLLOW THROUGHOUT THE REST OF THE EXTENDED PERIOD. SLIGHT CHANCE TO CHANCE POPS COVER THE CWA SUNDAY AFTERNOON THROUGH THE END OF THE PERIOD AS MOISTURE AND INSTABILITY LINGER IN TROUGH. THE INITIAL SURFACE COLD FRONT WILL COME THROUGH IN TWO PIECES...A DRY PRE-FRONTAL COOL PUSH EARLY SUNDAY...AND THEN THE MAIN COLD FRONT SUNDAY NIGHT. MAJORITY OF PRECIP APPEARS TO BE ALONG AND JUST BEHIND THE MAIN COLD FRONT. ANOTHER PIECE OF ENERGY IS FORECAST TO MOVE THROUGH IN THE TUESDAY/WEDNESDAY TIME-FRAME. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...NONE. OR...NONE. && $$ SHORT TERM..KP LONG TERM...RH id AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO IL 700 PM CDT WED SEP 8 2004 .DISCUSSION... AS ET FRANCES PULLS INTO THE NORTHEAST U.S. THE CURRENT NE SFC FLOW WILL BACK A FRAZ TOMORROW CONCURRENT WITH SLOW RELAXATION OF THE PRESSURE GRADIENT. THE CURRENT CLOUD DECK OVER NE IL IS EXPECTED TO EVAPORATE THIS EVENING AS LAPSE RATES BECOME SMALL DUE TO DECOUPLING. A FEW OVERNIGHT CU NEAR THE LAKESHORE WILL BE POSSIBLE IN COOK/LAKE CNTIES. THE DECK IS EXPECTED TO DEVELOP AGAIN TOMORROW BUT THIS TIME OVER NW IN AND PROBABLY NOT AS THICK DUE TO SMALLER PBL LAPSE RATES AS H85 TEMPS WARM A FEW DEGREES. HIGH PRESSURE WILL MOVE ACROSS THE REGION BECOMING CENTERED EAST OF THE CWA ON FRIDAY, ESTABLISHING RETURN PBL FLOW. THE WAA WILL THEN CONTINUE BEFORE COLD, DRY FROPA LATE SATURDAY AFTERNOON/EVENING. AFTER ABOVE NORMAL HIGH TEMPS ON SAT, TEMPS BEHIND THE FRONT WILL LOWER TO, OR BE SLIGHTLY BELOW NORMAL ON SUN. TEMPS WILL SLOWLY MODERATE INTO THE MIDDLE OF NEXT WEEK AS MID-LVL HEIGHTS RISE DUE TO MID-LVL RIDGING OVER THE REGION. THE DRY FCST SHOULD CONTINUE BEYOND THE SEVEN DAY FCST PERIOD. AEP && .AVIATION DISCUSSION FOR 00Z TAFS: NE WINDS WILL CONTINUE TO DECOUPLE OVER THE NEXT HOUR INTO THE 10 KNOT RANGE WITH A TENDENCY TO BACK TO THE NORTH. SKIES CLEAR THIS EVENING FOR MOST PART WITH JUST A FEW LINGERING CU EARLY THIS EVENING. WEAKLY DIFFLUENT FLOW NOTED UPSTREAM ACROSS IOWA WITH SHORT WAVE EVIDENT IN WV IMAGRY/RUC INITIALIZATION FIELDS ACROSS EASTERN IA. SOME MID LEVEL CIGS NOTED EARLIER WITH THIS FEATURE...BUT OVER PAST FEW HOURS MID CLOUD COVERAGED HAS DECREASED QUITE A BIT WITH AXIS OF DRY MID LEVEL AIR ASSOCIATED WITH WEAK MID/UPPER LEVEL RIDGING ACROSS ERN IA/NRN IL. JUST FEW-SCT AFT CU SHOULD DEVELOP ONCE AGAIN THURS MORNING...AND WINDS SHOULD BECOME NE BY LATE MORNING WITH MIXING. WIND SPEEDS LIKELY TO DROP OFF INTO 5 KNOT RANGE TOWARD END OF FORECAST PERIOD AS RIDGE AXIS SETTLES INTO THE AREA. NDM && .LOT...WATCHES/WARNINGS/ADVISORIES... .IL...NONE. .IN...NONE. .LK MI...SCA TODAY AND TONIGHT. $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PADUCAH KY 210 PM CDT WED SEP 8 2004 .DISCUSSION... IN THE NEAR TERM...THE MAIN FORECAST CONCERN CONTINUES TO REVOLVE AROUND THE PATH OF FRANCES AND ITS EFFECTS ON OUR FORECAST AREA. CENTER OF FRANCES AT EARLY AFTERNOON CENTERED NEAR THE CUMBERLAND GAP. WRAP AROUND MOISTURE/CLOUDS FROM THIS SYSTEM CURRENTLY COVERS APPROXIMATELY THE SOUTHEAST HALF OF THE CWA. AS THE REMNANTS OF FRANCES CONTINUE LIFTING TO THE NORTHEAST...EXPECT THE CLOUDS TO SLOWLY DECREASE FROM WEST TO EAST. LATEST FRAME OR TWO OF VISIBLE SAT PIX SHOWING THE WESTERN EDGE OF THIS CLOUDINESS MAKING A LITTLE PROGRESS EAST. ACCORDINGLY TO RUC AND ETA12...1000-850 RH ACTUALLY SURGES A LITTLE FARTHER WESTWARD BETWEEN NOW AND MIDNIGHT...BUT THE DEPTH OF THE LAYER BECOMES THINNER. THAT COMBINED WITH INCREASING DOWNWARD MOTION AND INCREASING HEIGHTS AT THE SURFACE AND ALOFT...AM INCLINED TO GO WITH A DECREASE OF CLOUDS FROM WEST TO EAST DURING THE FIRST PERIOD. HIGH PRESSURE AT THE SURFACE AND ALOFT WILL CONTINUE TO DOMINATE THROUGH SATURDAY NIGHT WHEN THE NEXT FRONT CROSSES THE CWA. DUE TO LACK OF MOISTURE HOWEVER...NO PRECIPITATION IS EXPECTED WITH THE FRONTAL PASSAGE AT THIS TIME. IN THE WAKE OF THIS FEATURE HIGH PRESSURE AT THE SURFACE AND RISING HEIGHTS ALOFT WILL KEEP THE REGION DRY WITH COOLER BUT SLOWLY MODERATING TEMPERATURES THROUGH THE END OF THE FORECAST PERIOD. FWC/MAV/MET MOS TEMPS SIMILAR AND REASONABLE SO ONLY MADE A FEW MINOR ADJUSTMENTS TO TEMPS. BIGGEST CONCERN TEMPERATURE-WISE WILL BE OVERNIGHT LOWS EARLY NEXT WEEK AFTER THE ABOVE MENTIONED FRONTAL PASSAGE. DGEX AND GFSLR IN LOUSY AGREEMENT ON WHERE SFC RIDGE AXIS WILL BE. IF GFSLR PANS OUT...OVERNIGHT LOWS WILL NEED TO BE LOWERED A BIT. FOR NOW WILL GO WITH THE CONSENSUS AND BLEND IN WITH SURROUNDING OFFICES UNTIL WE GET A STRONG SIGNAL TO DO OTHERWISE. && .PAH WATCHES/WARNINGS/ADVISORIES... KY...NONE. MO...NONE. IL...NONE. IN...NONE. && $$ JAP ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 313 PM EDT WED SEP 8 2004 .DISCUSSION... MAIN FORECAST CONCERN IS SYSTEM AFFECTING UPPER MICHIGAN FRIDAY THROUGH SATURDAY CURRENT WEATHER...18Z WATER VAPOR LOOP AND 500MB RUC HEIGHT ANALYSIS SHOWED ZONAL FLOW ACROSS THE NORTHERN TIER OF THE UNITED STATES WITH A TROUGH BEGINNING TO DIG INTO THE PACIFIC NORTHWEST. THREE NOTABLE FEATURES IN THE WATER VAPOR...THE REMNANTS OF HURRICANE FRANCES OVER EASTERN KENTUCKY...A SHRTWV MOVING INTO WESTERN MINNESOTA...AND A SHRTWV NEAR YELLOWSTONE NATIONAL PARK. SHRTWV OVER WESTERN MINNESOTA HAS BEEN PRODUCING A FEW LIGHTNING STRIKES ALONG WITH SHOWERS ON THE MPX RADAR. THESE SHOWERS HAVE HAD A HARD TIME MOVING INTO WISCONSIN THOUGH...AND LOOKING AT THE 12Z GRB SOUNDING THERE IS PLENTY OF DRY AIR ABOVE 800MB (DEWPOINT DEPRESSIONS OF 18C OR MORE). BELOW 800MB...THE SOUNDING HAS A NEAR DRY ADIABATIC LAPSE RATE...AND WITH DEWPOINTS IN THE LOW 50S...A DECENT CU FIELD HAS DEVELOPED ACROSS THE GREAT LAKES. AS FOR THE SURFACE PATTERN...HIGH PRESSURE EXTENDS FROM JAMES BAY TO IOWA WHILE LOW PRESSURE CENTERS WERE OVER NORTH CENTRAL MANITOBA AND NEAR RAPID CITY. TONIGHT...WITH THE REMNANTS OF FRANCES MOVING UP THROUGH THE MID-ATLANTIC...THE HIGH PRESSURE RIDGE OVER THE GREAT LAKES WILL REMAIN NEARLY STATIONARY. THEREFORE...EXPECTING THE CURRENT CU FIELD TO DISSIPATE THIS EVENING. LATE TONIGHT SOME MID-CLOUD WILL BEGIN SPREADING INTO THE FAR WESTERN U.P. (CURRENTLY OVER EASTERN NORTH DAKOTA)...BUT OTHERWISE IT SHOULD BE ANOTHER GOOD RADIATIONAL COOLING NIGHT AS WINDS DROP OFF. MODEL PROGS HAVE DEWPOINTS LOWERING TO ABOUT THE MID 40S...AND WILL GO NEAR THAT FOR TEMPS. THURSDAY...PATTERN REMAINS NEARLY THE SAME. HIGH PRESSURE STAYS STATIONARY OVER THE GREAT LAKES...SQUEEZED INBETWEEN THE REMNANTS OF FRANCES AND LOW PRESSURE DEVELOPING ALONG THE LEE OF THE ROCKIES AS A RESULT OF THE ZONAL FLOW ALOFT. OTHER THAN SOME MID-CLOUD PASSING THROUGH AND THE TYPICAL DIURNAL CU...EXPECT ANOTHER QUIET DAY. WITH 850MB TEMPS OF 6-8C...TEMPERATURES WILL RISE INTO THE UPPER 60S/LOW 70S...COOLEST ALONG LAKE SUPERIOR DUE TO LAKE BREEZES DEVELOPING IN THE AFTERNOON. THURSDAY NIGHT...WITH FRANCES NOW CAUGHT UP IN THE ZONAL FLOW...THE HIGH PRESSURE RIDGE BEGINS MOVING EAST AND LOW PRESSURE TRIES TO CONSOLIDATE ITSELF OVER SOUTH DAKOTA (IN RESPONSE TO A SHRTWV ASSOCIATED WITH THE TROUGH NOW ENTERING THE PACIFIC NORTHWEST). THE WARM FRONT ASSOCIATED WITH THIS LOW SETS UP FROM PIERRE TO OSHKOSH. SOUTH OF THIS FRONT...THE ETA AND GFS ARE INDICATING 850MB TEMPS OF GREATER THAN 18C AT 12Z FRI (24C ON THE ETA OVER SIOUX FALLS SOUTH DAKOTA). A 30-40KT LOW LEVEL JET LOCATED WITHIN THE WARM SECTOR WILL HELP DEVELOP SOME CLOUDS OVER NORTHERN WISCONSIN OVERNIGHT DUE TO ISENTROPIC LIFT...HOWEVER LOW-LEVEL FLOW FROM THE SOUTHEAST COMING OUT OF THE HIGH PRESSURE CURRENTLY OVERHEAD WILL KEEP THE LOW LEVELS DRY. THEREFORE NOT EXPECTING PRECIPITATION. MIN TEMPS WILL BE COOL AGAIN OUT EAST WHERE WINDS CAN DECOUPLE...BUT WARMER TEMPS OUT WEST DUE TO A STRONGER WIND AND LITTLE HIGHER DEWPOINTS. FRIDAY...GFS/ETA AND UKMET HAVE THE WARM FRONT MOVING NORTH THROUGH THE U.P. AS A TROUGH BEGINS TO FORM OVER THE NORTHERN PLAINS. THIS ALLOWS 850MB TEMPS TO RISE TO 14-16C BY 18Z. MAIN CONCERN HERE IS THAT BOTH THE ETA AND GFS SHOW DECENT VERTICAL MOTION DURING THE AFTERNOON AS THE WARM FRONT MOVES THROUGH...HOWEVER THE MODELS DO NOT PRODUCE ANY QPF. LOOKING AT AREA SOUNDINGS...THERE IS NEARLY A DRY-ADIABATIC LAPSE RATE FROM 750-500MB...HOWEVER DEWPOINT DEPRESSIONS BELOW 700MB ARE 10-20C. SO RIGHT NOW IT LOOKS LIKE DRY AIR WILL KEEP ANY PRECIPITATION FROM FORMING. OTHERWISE...WITH SOME SUNSHINE IN-BETWEEN THE PASSING CLOUDS ON THE WARM FRONT AND 15-20KT SOUTHERLY SURFACE WINDS (DUE TO THE LOW-LEVEL JET MOVING OVERHEAD)...TEMPERATURES WILL RISE INTO THE MID 70S. LOCATIONS ALONG LAKE MICHIGAN WILL STAY COOLER WITH THE SOUTH FLOW OFF THE LAKE. FRIDAY NIGHT INTO SATURDAY...DIFFERENCES SHOW UP WITHIN THE MODELS IN TERMS OF HOW FAST THE AFOREMENTIONED SHRTWV TROUGH MOVES ACROSS THE UPPER MISSISSIPPI VALLEY INTO THE GREAT LAKES. THE ETA IS THE SLOWEST...HAVING THE SHRTWV TROUGH OVER WESTERN MINNESOTA (ALSO WEAKER) WHEREAS THE GFS AND UKMET HAVE IT OVER WESTERN LAKE SUPERIOR AT 12Z SAT. THIS HAS GREAT INFLUENCE ON HOW STRONG THE WINDS WILL BE BEHIND A SURFACE LOW ASSOCIATED WITH THE TROUGH AND HOW WARM WE WILL GET. PER HPC/S PMDHMD DISCUSSION...WILL FOLLOW A COMPROMISE. THIS COMPROMISE PUTS A SURFACE LOW A LITTLE NORTHEAST OF THUNDER BAY WITH ITS ASSOCIATED COLD FRONT EXTENDING SOUTHWEST TO THE APOSTLE ISLANDS AT 12Z SAT. WITH THE UPPER PENINSULA IN THE WARM SECTOR FRIDAY NIGHT...A 30-40KT LOW-LEVEL JET OVERHEAD (RESULTING IN BREEZY SURFACE WINDS) AND A CIRRUS DECK MOVING IN...NOT EXPECTING TEMPERATURES TO FALL MUCH. MAV GUIDANCE AND CURRENT FORECAST LOWS ARE IN THE UPPER 50S...BUT LOOKING AT THE PATTERN AND DEWPOINTS IN THE MID TO UPPER 50S...WILL RAISE TEMPS A FEW DEGREES. ON SATURDAY...COLD FRONT MOVES THROUGH DURING THE DAY...ALLOWING FOR MIXING AND GUSTY WINDS BEHIND IT. PRECIPITATION ASSOCIATED WITH THE FRONT IS A PROBLEM. ETA INDICATES THE AIR WILL BE TOO CAPPED SO IT DOES NOT PRODUCE ANY PRECIPITATION. THE GFS AND THE UKMET INDICATE A LINE OF CONVECTION DEVELOPING ALONG THE FRONT (AS A RESULT OF A STRONGER AND DEEPER SHRTWV TROUGH). CURRENT FORECAST HAS A CHANCE OF SHOWERS AND THUNDERSTORMS IN AND THEREFORE WILL NOT CHANGE. TEMPERATURES ARE A SERIOUS PROBLEM GIVEN THAT IF THE ETA IS CORRECT...PLACES IN THE CENTRAL AND EASTERN U.P. COULD RISE WELL INTO THE 80S. HOWEVER THE GFS AND UKMET SUGGESTS LOW 70S. EITHER WAY IT LOOKS LIKE THE WESTERN U.P. WILL STAY IN THE UPPER 60S AS 850MB TEMPS FALL FROM 14C AT 12Z TO 6C AT 00Z. EXTENDED (SUNDAY THROUGH WEDNESDAY)...SHRTWV TROUGH OVER THE UPPER PENINSULA ON SATURDAY MOVES INTO THE NORTHEAST WHILE TROUGHING FORMS OVER THE PACIFIC NORTHWEST. THIS RESULTS IN AN AMPLIFIED RIDGE BUILDING ACROSS THE CENTRAL UNITED STATES. THERE IS GOOD MODEL AGREEMENT ON THIS OCCURRING...HOWEVER THE TIMING ON HOW QUICK THE RIDGE AXIS MOVES EAST IS STILL IN QUESTION. THE 00Z/06Z/12Z GFS...ITS ENSEMBLES AND THE 00Z ECMWF SUGGEST THE RIDGE AXIS OVER THE U.P. MONDAY EVENING WHEREAS THE 00Z UKMET IS SLOWER...REACHING MINNESOTA. FOR NOW WILL HEDGE TOWARDS THE ENSEMBLES BUT WOULD NOT BE SURPRISED IF THE RIDGE AXIS IS SLOWER...ESPECIALLY IF THE PATTERN DOES AMPLIFY A LOT. AFTER MONDAY...UPPER MICHIGAN REMAINS IN SOUTHWESTERLY FLOW ALOFT AS SHRTWV ENERGY CONTINUES TO DROP INTO THE WESTERN TROUGH. AT THE SURFACE...HIGH PRESSURE WILL MOVE ACROSS UPPER MICHIGAN ON SUNDAY...BRINGING A COOL SHOT OF AIR WITH IT (850MB TEMPS 4-6C). EXPECT THE HIGH TO MOVE EAST ON MONDAY AS THE UPPER RIDGE AMPLIFIES...ALLOWING 850MB TEMPS TO RISE UP TO 10-12C. ECMWF IS WARMER (AROUND 18C) BUT THIS IS DUE TO A FASTER MOVEMENT OF THE RIDGE AXIS. BY TUESDAY...THE SURFACE HIGH WILL BE OVER NEW ENGLAND AS A COLD FRONT APPROACHES WESTERN LAKE SUPERIOR. LOOK FOR ANOTHER WARM DAY AS 850MB TEMPS ARE 15-16C...BUT WITH THE APPROACH OF THE COLD FRONT...LOOK FOR INCREASING CLOUD COVER WITH A CHANCE FOR PRECIPITATION LATE IN THE DAY WEST. EXPECT THE COLD FRONT TO GRADUALLY MOVE INTO UPPER MICHIGAN ON WEDNESDAY...BRINGING A CHANCE FOR SHOWERS AND THUNDERSTORMS WITH IT ALONG WITH NEAR NORMAL TEMPS. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ AJ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 256 PM EDT WED SEP 8 2004 .SHORT TERM... THERE ARE TWO PROBLEMS OF SIGNIFICANCE FOR THIS PACKAGE. FIRST UP IS THE EXTENT OF THE LOW CLOUD COVERAGE TONIGHT SINCE THE ETA AND GFS BOTH SHOW THE 925 TO 850MB MEAN RH RISES ABOVE 90PCT OVER MOST OF OUR CWA BY 03Z TONIGHT. THE SECOND ISSUE IS THE COLD FRONT AND IT'S ASSOCIATED CONVECTION SATURDAY EVENING (TIMING A QUESTION TOO). TONIGHT...OVERALL COMPARING SFC OBS TO MODEL WORLD LAYERED RELATIVE HUMIDITY FIELDS...SEEMS THE 90PCT 925 TO 850MB MEAN RH MATCHES THE AREA WHERE THE LOW CLOUDS COVERAGE IS GREATER THEN 50 PERCENT. THAT SPREADS WEST TO GRR BY 03Z AND ALMOST GETS TO RQB BY 06Z. HOWEVER...AFTER 06Z IT RETREATS SO THAT BY 12Z IT'S FROM GRR TO FNT. THE RUC THROUGH 03Z IS QUIET SIMILAR TO THE ETA. EVEN SO...WATCHING THE VISIBLE SATELLITE LOOPS IT SEEMS THE LOW CLOUDS WILL NOT SPREAD QUIET THAT FAR WEST. SO I WILL GO WITH MOSTLY CLOUDY OVER THE EASTERN CWA (ENOUGH HIGH CLOUDS ANYWAY)TONIGHT...CONSIDERABLE CLOUDS OVER THE CENTRAL CWA AND PARTLY CLOUDY OVER THE WESTERN SECTIONS. THURSDAY THE SYSTEM MOVES OUT AND HIGH PRESSURE MOVES IN. THAT BRINGS DRY AIR DOWN FROM THE NORTH SO JUST SCT CU DURING THE AFTERNOON. THURSDAY NIGHT SKIES CLEAR AND WINDS BECOME LIGHT. LIKELY IT WILL BE A CHILLY NIGHT WITH MOST INTERIOR LOCATIONS FALLING INTO THE 40S NORTH AND CENTRAL...LOWER 50S SOUTH. THE LONGER NIGHTS SHOULD HELP THAT CAUSE. FRIDAY THE WARM ADVECTION STARTS...BUT NOT MUCH MOISTURE TO DO ANYTHING WITH IT. SO PARTLY CLOUDY SHOULD DO IT. HIGHS WILL PUSH NEAR 80. NOT MUCH CHANGE SATURDAY NIGHT...WARM ADVECTION BUT LIMITED MOIST LIMITED...PARTLY CLOUDY SHOULD WORK. SATURDAY THE FRONT MOVES IN THE ETA BEING MUCH SLOWER THAN THE GFS. ACTUALLY THE CANADIAN IS SLOWER THAN THE GFS TOO. EVEN SO THE GFS HAS BEEN RATHER CONSISTENT WITH THE FRONT. SO I WILL FAVOR THAT FOR NOW. WARM SURGE AHEAD OF THE FRONT WILL ALLOW HIGHS IN THE 80S. SURFACE BASED LI IS NEGATIVE...JET EXIT REGION LIFT AND GOOD DPVA EVEN THOUGH MOISTURE IF FEEBLE. SO WILL GO WITH SHOWERS/THUNDERSTORMS OVER THE NRN CWA AND CALL THAT GOOD. .LONG TERM... 12Z GFS AND ETA GUIDANCE AS WELL AS CANADIAN GUIDANCE REMAIN IN REASONABLY GOOD AGREEMENT IN SHOWING THE COLD FRONT WILL MOVE THROUGH OUR AREA SATURDAY NIGHT. THEREFORE WE WILL MAINTAIN LOW CHC POPS FOR CONVECTION WITH THAT FEATURE. IT APPEARS THE BEST CHANCE FOR ACTIVITY WILL BE ACROSS OUR NORTHERN CWA WHERE MUCH STRONGER PVA WILL OCCUR. HOWEVER, MOISTURE WITH THIS SYSTEM LOOKS QUITE MEAGER SO THE OVERALL CHANCES FOR PCPN ARE PRETTY SLIM AS WE REMAIN LOCKED IN A FAIRLY DRY WX PATTERN OVERALL IN OUR AREA. BEHIND THAT FRONT AND DEPARTING SHORTWAVE IT STILL LOOKS LIKE A LARGE SFC HIGH PRESSURE RIDGE WILL BUILD IN AND PRODUCE CLEAR TO PARTLY CLOUDY SKIES EARLY NEXT WEEK. A LOW AMPLITUDE UPPER RIDGE WILL GRADUALLY BUILD IN TOO. THE WILD CARD IN THE EXTENDED RANGE FORECAST IS TO FIGURE OUT WHERE THE REMNANTS OF HURRICANE IVAN WILL TRACK, BUT FOR NOW WE'LL STICK WITH A DRY FORECAST THROUGH WEDNESDAY GIVEN THE SFC/UPR LEVEL RIDGING OVER OUR AREA. && .GRR WATCHES/WARNINGS/ADVISORIES...NONE. $$ WDM LAURENS mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1000 AM EDT WED SEP 8 2004 .UPDATED... I AM CONCERNED ABOUT THE AMOUNT OF CLOUD OVER OVER THE CNTRL AND EASTERN SECTIONS OF OUR COUNTY WARNING AREA THIS AFTERNOON INTO TONIGHT. BOTH THE MODEL SOUNDINGS AND THE 12Z RAOB FROM DTX SUGGEST A FAIRLY MOIST LAYER BELOW 5000 FT (850MB) AT 12Z. WHILE IT IS TRUE THAT THE LOW CLOUD FORECAST (USING THE MEAN RH FROM 925 TO 850MB FROM THE RUC WITH CIGS HEIGHTS) SUGGESTS THE LOW CLOUDS COULD REACH AS FAR WEST AS JXN BY 21Z THIS AFTERNOON...THAT MOIST LAYER BELOW 850MB DISTURBS ME IN THE SENSE THAT THE LOW CLOUD DECK COULD BE AS FAR WEST AS US-131 BY MID TO LATE AFTERNOON. IT COULD WELL BE WITH HEATING THAT A BROKEN LOW CLOUD DECK...WITH BASES NEAR 3000FT AGL... FORMS OVER A GOOD PART OF THE CWA IN THAT MOIST LOW LEVEL EASTERLY FLOW. WHAT IS AGAINST THAT IS THE STRONG SUBSIDENCE SEEN ON THE AGEOSTROPHIC CIRCULATION VECTORS OVER SOUTHWEST LOWER MICHIGAN FROM 300MB DOWN TO 850MB. SEEMS TO ME ALL OF THAT SUBSIDING DRY AIR SHOULD MIX AT LEAST SOME WITH THAT LOWER MOIST LAYER. FOR NOW I WILL BELIEVE THAT THE HIGH CLOUD DECK IS THIN ENOUGH... EVEN THROUGH IT WILL BE NEAR OVERCAST ABOVE 25000FT...FROM I-69 EAST... THAT PARTLY CLOUDY WILL WORK FINE. THAT TOO MAY HAVE TO BE RECONSIDERED. SO...FOR NOW I WILL LEAVE ALL AS IS AN BELIEVE THE GOING FORECAST IS FINE AND LEAVE IT AS IT IS. HOWEVER...IF I NOTE A TREND TOWARD A BROKEN STRATOCUMULUS DECK MOVING IN...OR THE CIRRUS DECK LOWERS TO AN ALTOSTRATUS DECK...I WILL UPDATE THE FORECAST TO REFLECT THAT. LIKELY WOULD BE EAST OF GRR IF AT ALL. && .GRR WATCHES/WARNINGS/ADVISORIES...NONE. $$ WDM mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 536 PM CDT WED SEP 8 2004 HAVE UPDATED FORECAST TO INCLUDE ISOLATED SHOWERS TONIGHT. CURRENT OBSERVATION FROM FGF OFFICE IS LIGHT SHOWERS ASSOCIATED WITH WEAK RETURNS FROM KMVX RADAR. WARM AIR ADVECTION IS STRONGER THAN MODELS INDICATE. RUC SUGGESTS WARM AIR ADVECTION TO STRENGTHEN THROUGH MIDNIGHT...ALONG WITH 850MB LOW LEVEL JET (30KTS). LACK OF MOISTURE SHOULD KEEP SHOWERS MORE ISOLATED. WITH THIS...UPDATED SKY COVER TO HANG ON TO MOSTLY CLOUDY WORDING A BIT LONGER. WILL MONITOR TRENDS FOR EVENING UPDATE. PREVIOUS DISCUSSION... .SHORT TERM... MOST EARLY CONCERNS REMAIN IN THE DAY 2/DAY 3 TIME FRAME AND HOW EXACTLY THE NEXT SFC LOW/FRONT PLAY OUT. STILL HAVE WIDE MODEL SOLUTIONS SO CHOSE TO STAY CLOSER TO THE ETA/CONTINUITY. TONIGHT...SOME SHOWERS STILL OVER THE FAR SOUTHERN FA...MOVING VERY SLOWLY TO THE EAST. WILL HAVE TO MONITOR AND SEE IF THEY WILL NEED TO BE INCLUDED IN THE EARLY PART OF TONIGHTS FORECAST. SHOWERS UP IN THE KDVL REGION HAVE PRETTY MUCH DRIED UP. LOTS OF CUMULUS CLOUD FORMATION AGAIN THIS AFTERNOON...BUT MOSTLY ALONG/EAST OF THE RED RIVER VALLEY. AGAIN...EXPECT THIS TO DISSIPATE EARLY THIS EVENING. SFC WINDS LOOK TO DECREASE AS WELL THIS EVENING. WITH NOT A LOT OF CLOUD COVER OVERNIGHT...COULD BE SOME RADIATION FOG DEVELOPMENT LATE. HOWEVER...WILL NOT MENTION IN THE FORECAST ATTM AS IT WAS PRETTY SPOTTY THIS (WED) MORNING. SFC PRESSURE GRADIENT ALSO SHOULD STAY UP ENOUGH TO KEEP MOST OF THE FOG AT BAY...SO WILL LET THE EVENING CREW MONITOR THAT. THU/THU NIGHT... EXPECT SFC LOW PRESSURE TO DEVELOP OVER THE EASTERN SLOPES OF THE ROCKIES ON THU. 850 MB TEMPS LOOK TO RISE 6C (PLUS) OVER TODAYS... SO LOOKING FOR A WARMER DAY. DECIDED TO KEEP SLIGHT CHANCE OF PCPN IN THE FORECAST STARTING THU NIGHT AS CONTINUITY HAD IT. SOME WEAK INSTABILITY OVER THE FA ALONG WITH THE POTENTIAL SFC BOUNDARIES (ALBEIT WEAK). WEAK WAVES IN THE QUICK ZONAL FLOW COULD FIRE UP SOMETHING...AND IT IS ONLY A SLIGHT CHANCE. FRI/SAT...AS MENTIONED PREVIOUSLY...BIGGER MODEL DIFFERENCES START COMING INTO PLAY HERE. WILL KEEP BROADBRUSHED LOW PCPN CHANCES THRU THE DAY FRI. BETTER CHANCES LOOK TO ARRIVE WITH STRONGER WAVE WHICH BOTH THE ETA/GFS BRING IN FRI NIGHT INTO SAT. HOW FAST THE FRONT COMES THRU WILL DETERMINE THUNDER OR SHOWER CHANCES AND HIGH/LOW TEMPS IN THIS TIME FRAME. GFS REMAINS COLDER THAN THE ETA...WHICH ALSO SHOWS UP THE MODEL MOS TEMPS. WILL LEAN MORE TOWARD SLOWER ETA/CANADIAN/UKMET SOLUTIONS FOR NOW WHICH MEANS FEW OVERALL CHANGES TO THE FORECAST/GRIDS. .LONG TERM...SUN THROUGH WED...GFS AND ECMWF ARE IN PRETTY GOOD AGREEMENT...WITH UKMET THE ODD MODEL OUT. 500MB RIDGE BUILDS INTO AREA...WITH AREA OF LOW PRESSURE MOVING INTO REGION AND BRINGING A CHANCE FOR THUNDERSTORMS ON MON. THEN...AREA REMAINS UNDER SW 500MB FLOW THROUGH THE REMAINDER OF THE EXTENDED...WITH BEST INSTABILITY REMAINING W AND S OF REGION. AS FAR AS TEMPS...KEPT NEAR TO SLIGHTLY ABOVE NORMAL. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ GODON/NG/TG nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 908 PM EDT WED SEP 8 2004 .SHORT TERM /OVERNIGHT/... RATHER STRONG MOISTURE CONVERGENCE CONTINUES ALONG THE CENTRAL AND NORTHERN COAST OF SOUTH CAROLINA THIS EVENING. A THIN BUT PERSISTENT BAND OF VERY HEAVY RAIN SHOWERS WAS LOCATED BETWEEN WALTERBORO AND CHARLESTON...NE TO BERKELEY COUNTY PRODUCING LOCALIZED 1 TO 2 INCH RAINS. SKIES WERE MOSTLY CLOUDY INLAND AND PARTLY CLOUDY CLOSER TO THE COAST. WILL UPDATE OUR ZONE PACKAGE TO LOWER WIND SPEEDS IN MOST GROUPINGS AND LOWER POPS TO 20 PCNT GEORGIA WHILE KEEPING SLIGHTLY HIER POPS IN SOUTH CAROLINA GROUPS OVERNIGHT. LOW TEMPS AND SKY COVER LOOK FINE. && .LAKE MOULTRIE WINDS... LATEST OBSERVATIONS AND TRENDS FROM THE SANTEE COOPER DAM AND SURROUNDING SITES SUPPORTS CANCELING THE WIND ADVISORY. WILL DO SO SHORTLY. && .MARINE... PRES GRAD A LITTLE BETTER OVER THE SC WATERS THAN THE GA WATERS THIS EVE AND LOOKS TO REMAIN THAT WAY OVRNGT PER THE RUC. RUC SPEEDS ANALYZE WELL SO WILL USE IT FOR THE MARINE UPDATE. WILL NEED TO TWEAK THE WORDING FOR TNGT TO UP THE SPEEDS A BIT IN THE SC WATERS AS BOTH FOLLY BEACH AND CHS HARBOR STILL COMING IN WITH 20-25 KT SUSTAINED WINDS WITH GUSTS TO 30 KT. WILL THEN IMPROVE THE TREND GOING INTO TMRW. AS SUCH...WILL MAINTAIN SCA FOR ALL WATERS. ONLY ZONE THAT COULD POSSIBLY BE REDUCED TO SCEC WOULD BE THE GA NEARSHORE...BUT GUSTS WILL LIKELY POKE OVER THE 25 KT CRITERIA AND AM NOT CONFIDENT WAVES WILL BE SOLIDLY BELOW 6 FT. SPEAKING OF WAVE CONDS...ALL ZONES SEEM TO HAVE WAVES HANDLED WELL SO DO NOT ANTICIPATE ANY CHANGES THERE. && .AVIATION... BKN-OVC 4-5 KFT CIGS MAINLY INLAND IN THE WAKE OF THE DEPARTING TROPICAL REMNANT. VCSH IN THE CHS TAF OK FOR NOW BUT WE MAY NEED TO AMEND FOR RAIN AT THE TERM THIS EVENING. OTHERWISE...WINDS ALREADY HAD DIMINISHED AT SAV BUT STILL GUSTING AT CHS. WINDS SHOULD CONTINUE TO SLOWLY SUBSIDE AT CHS TERM OVERNIGHT. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY AMZ330-350-352-354-374. && $$ 24/JPC sc AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 1039 AM EDT WED SEP 8 2004 .SHORT TERM (REST OF TODAY)... SFC REFLECTION OF THE REMNANTS OF FRANCES HAS NOW MOVED JUST NORTH OF THE CWFA...TO A POSITION ROUGHLY OVER GREENE COUNTY TN. FLOW ON THE KGSP WSR88D VAD WIND PROFILE NOW HAS A COMPONENT JUST WEST OF SOUTH (ABOUT 190 DEGREES)...A WELCOME SIGHT. WINDS IN THE IMMEDIATE LEE... PARTICULARLY IN NC...WL STILL HAVE AN UPSLOPE COMPONENT FOR A FEW MORE HOURS. WITH SUCH A WARM SATURATED AIRMASS...ENOUGH PCPN COULD STILL BE WRUNG OUT TO HELP MAINTAIN CURRENT FLOODING...THOUGH IT DOESN/T LOOK LIKE THERE WL BE ENUF TO CAUSE ANY NEW FLOODING. CURRENT POP AND QPF DISTRIBUTION LOOKS GOOD IN THE GRIDS AND SEE NO REASON TO CHANGE THEM. WL KEEP FLOOD WATCH UP AS WELL. POLICY HERE IS NOT TO CANCEL WATCHES WITH FLOODING ONGOING. ALSO...SEVERAL EARTHEN DAMS IN THE MOUNTAINS AND FOOTHILLS ARE IN A THREATENED CONDITION...SO WE WL NEED TO KEEP THE WATCH UP FOR THE POSSIBILITY OF DAM FAILURES AS WELL. 12 UTC UPPER AIR HAND ANALYSIS REVEALS AN AREA OF VERY WARM MID LEVEL TEMPERATURES WRAPPING AROUND THE SOUTH SIDE OF FRANCES. THIS ALSO SHOWS UP WELL AS AN AREA OF PRONOUNCED DRYING ON THE WATER VAPOR IMAGERY. AT 14 UTC THE RUC HAD A LARGE AREA OF -4 DEG C TEMPS AT H5 COVERING ABOUT THE SW HALF OF THE CWA. WITH SUCH A WARM AIRMASS ALOFT IT WILL BE VERY DIFFICULT TO DEVELOP ANY NEW...STRONG CONVECTION BEHIND THE LAST OF THE WARM CONVEYOR BELT PCPN WHICH HAS NOW EXITED TO THE EAST...AND DO NOT PLAN TO ISSUE A SEVERE WEATHER OUTLOOK. WHILE WE DO DRY AND WARM ALOFT...BOTH ETA AND GFS KEEP US SOPPING WET BLO ABOUT 500 MB. THEREFORE WL KEEP CURRENT CLOUDY CONDITIONS AND COOL TEMPS IN THE GRIDS. && .PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 730 AM EDT WED SEP 8 2004 SHORT TERM (TODAY THROUGH THURSDAY)... TORNADO WATCH 812 HAS BEEN REPLACED WITH TORNADO WATCH 813... NECESSITATING AN UPDATE TO THE ZFP. WILL TAKE THIS OPPORTUNITY TO FINE TUNE PRECIP DEPARTURE TIMING LATE TODAY FROM THE SOUTH. THIS SHOULD RESULT IN LOWER PRECIP CHANCES ACROSS SOUTHERN ZONES FOR THE TONIGHT PERIOD. THE REMAINDER OF THE FORECAST LOOKS OK. PREV DISCUSSION... ISSUED AT 355 AM. SHORT TERM (TODAY THROUGH THURSDAY)... AREA RADARS SHOW A BACK EDGE TO THE MAIN PRECIP WORKING INTO SOUTHERN ZONES...WRAPPING AROUND THE LOW CENTER...LOCATED OVER N GA AT 07Z. THIS SUGGESTS A TAPERING OF POP FROM THE SOUTH THIS MORNING. HOWEVER...EXPECT THAT AFTER SUNRISE...AND WITH SOME HEATING...THERE WILL BE ENOUGH FORCING AND MOISTURE TO RESULT IN SHOWERS REDEVELOPING ACROSS THE SOUTH. POP WILL BE KEPT CATEGORICAL THROUGHOUT THE DAY...UNTIL CIRCULATION CENTER OF FRANCES REMNANT LOW IS SAFELY PAST THE FORECAST AREA LATE IN THE DAY. ALTHO MOST OF THE HEAVY RAIN IS PROBABLY OVER IN THE SOUTHERNMOST ZONES...FLOOD WATCH WILL BE KEPT ACROSS ENTIRE FORECAST AREA IN THE EVENT THAT NEW FLOODING DEVELOPS AS WATER MOVES THRU WATERSHEDS. MAIN WIND THREAT IS GRADUALLY LIFTING NORTHWARD AHEAD OF THE LOW. A POTENTIAL REMAINS ACROSS THE NORTHERN ZONES THROUGH THE MORNING. THE HIGH WIND WARNING RUNS OUT AT 6 AM...THINK ADVISORY SHOULD TAKE CARE OF NORTHERN MOUNTAINS THROUGH NOON. EXPECT TO BE DEALING WITH TORNADO THREAT THROUGH THE MORNING AS WELL. A SEVERE WEATHER OUTLOOK WILL BE ISSUED TO ADDRESS THIS. NO REAL WHOLESALE CHANGES HAVE BEEN MADE ON THE WINDING DOWN OF THE BIG FRANCES REMNANT PRECIP EVENT. KEPT HIGH POP ACROSS THE NRN HALF OF THE FORECAST AREA INTO THE EARLY MORNING HOURS TONIGHT. HAVE KEPT SOME SEMBLANCE OF CHANCE POP ON THURSDAY AS WELL...OWING TO LOW LEVEL CONVERGENCE IN THE WAKE OF REMNANT LOW ACTING ON REMAINING LOW LEVEL MOISTURE. AS FOR TEMPS...HAVE ALLOWED FOR THE SUN TO PEEK OUT ACROSS THE SOUTHERN ZONES...SO TEMPS HAVE BEEN RAISED A FEW DEGREES THERE TODAY. MAV GUIDANCE LOOKS TOO COOL. LONG TERM (THURSDAY NIGHT THROUGH TUESDAY)... LATEST GFS SHOWS SURFACE RIDGE BUILDING IN FROM THE WEST BY 12Z FRIDAY...WITH SOME DRYING AND DOWNSLOPE WIND COMPONENT. THE MODEL RESPONDS BY KEEPING WESTERN CAROLINAS DRY THRU THE WEEKEND. WILL ADJUST PRECIP FORECAST ACCORDINGLY BY KNOCKING OUT SOME OF THE SLIGHT CHANCE POP IN THE GRIDS...BUT THIS SHOULD HAVE LITTLE EFFECT ON THE ZFP/AFM. NO CHANGES MADE PAST SUNDAY. TEXT PRODUCTS SHOULD BE AVAILABLE AROUND 430 AM. EXPECT MORNING UPDATE WHEN TOR WATCH 812 RUNS OUT OR IS REPLACED. AVIATION... THE CENTER OF THE LOW OVER KPDK AT 06Z WITH MODERATE TO HEAVY RAIN NE OF THE LOW OVER THE WESTERN CAROLINAS. THE MAIN SHIELD OF RAIN APPEARS TO LIFT NORTH OF SC BY 12Z AND NC BETWEEN 21-24Z. SFC COND PRES DEF REMAIN VERY LOW OVER ACTIVE TERMINALS UNTIL 13Z...WILL FORECAST WIDESPREAD AND PERSISTENT IFR CEILINGS UNTIL SHORTLY AFTER SUNRISE. SHOWERS SHOULD CONTINUE DEVELOP IN THE AREAS AFTER THE PRECIP SHIELD AND WILL CONTINUE PRECIP MENTION THROUGHOUT THE TAF PERIOD...KCLT WOULD HAVE THE BEST CHC FOR PM TS. AS THE LOW MOVES NORTH THE PRESSURE GRADIENT RELAXES AND WINDS SHOULD WEAKEN AND BECOME MORE SOUTH TO SOUTHWEST. IFR TO LIFR CEILINGS AND POSSIBLY VIS CONDITIONS SHOULD RETURN SHORTLY AFTER SUNSET...ESPECIALLY AT KAVL. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...FLOOD WATCH FOR ZONES GAZ010-017-018-026-028-029 UNTIL 6 PM EDT. NC...FLOOD WATCH FOR ZONES NCZ033>035-037-038-048>059-062>072- 082 UNTIL 6 PM EDT. ...WIND ADVISORY FOR ZONES NCZ033-049-050 UNTIL 12 PM EDT. ...LAKE WIND ADVISORY FOR ZONES NCZ033>035-037-038-048>059- 062>069 UNTIL 6 PM EDT. SC...FLOOD WATCH FOR ZONES SCZ001>014-019 UNTIL 6 PM EDT. && $$ SHORT TERM (UPDATE)...MCAVOY sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CORPUS CHRISTI TX 820 PM CDT WED SEP 8 2004 .UPDATE...MSAS ANALYSIS SHOWING SFC THETA-E GRADIENT LOCATED ALONG WEAK TROF OFFSHORE ACROSS THE NORTHERN WATERS AND BENDING CLOSER TO THE COAST ACROSS THE SRN COASTAL WATERS. ALSO EVIDENT WITH BUOY 42019 SHOWING A NORTHEAST WIND AND PTAT2 AND 42020 INDICATING A NORTH WIND. SHOWERS AND AN ISOL TSTM HAVE DEVELOPED ACROSS THE WATERS IN AREA OF MOISTURE CONVERGENCE. MOISTURE CONVERGENCE WILL SHIFT SOUTH THROUGH THE OVERNIGHT. ELSEWHERE...H85-7 VORT CENTER BETWEEN DRT AND HDO HAS BEEN DRIFTING SLOWLY SOUTH. IN RESPONSE...WINDS ON THE 305K SFC HAVE VEERED ERLY TODAY...ALSO SHOWN ON THE VAD AT 7K FT. THIS HAS RESULTED IN WEAK UPGLIDE PRODUCING BKN MID LVL CLOUD DECK...WHICH HAS OVERSPREAD THE ERN CWA ALONG WITH PATCHY LIGHT RAIN ACROSS THE COASTAL BEND. ETA/GFS/RUC ALL SHOW VORT CENTER CONTINUING TO DRIFT SOUTH OVERNIGHT...DOWN THE RIO GRANDE AND INTO MEXICO. GFS HAS BEEN HANDLING THE ISENTROPIC AND CLOUD PATTERN A LITTLE BETTER SO WILL FOLLOW THIS FOR THE REMAINDER OF THE NIGHT. CLOUD DECK SHOULD BUILD SLOWLY WEST ACROSS THE CWA OVERNIGHT. WILL KEEP PATCHY LIGHT RAIN GOING ACROSS THE EAST...BUT GFS AND ETA ARE BOTH SHOWING UPGLIDE TO WEAKEN SLIGHTLY ACROSS THE EAST BY MORNING. TEMPS TONIGHT WILL BE TRICKY...DEPENDENT ON CLOUDS AND WINDS. WILL BE RAISING TEMPS IN THE UPDATE IN SOME LOCATIONS BASED UPON CURRENT TRENDS. WILL ALSO BE RAISING WINDS OVER THE SRN BAYS AND WATERS UP INTO SCEC RANGE FOR THE REMAINDER OF THE EVENING...AS INDICATED BY CURRENT OBS AND GFS MOS...THEN WEAKENING BACK TO 10-15 KT RANGE AFTER MIDNIGHT. && .CRP WATCHES/WARNINGS/ADVISORIES...NONE. && $$ 76...SHORT-TERM tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 300 PM CDT TUE SEP 7 2004 .SHORT TERM...GOES SOUNDER SHOWS PWS DOWN TO 1.5 INCHES FROM 12Z SOUNDING OF 2 INCHES. DRY COOL AIR ADVECTION IS BEGINNING TO DIMINISH AS FRONT STALLS ACROSS NE MEXICO. 18Z MSAS INDICATES WEAK LOW/COASTAL TROFING HAS FORMED IN THE WESTERN GULF OF MEXICO. THIS TROF COMBINED WITH A WEAK VORT MAX TO PRODUCE THE SHOWERS OFFSHORE TODAY. RUC AND ETA PROG THIS TROF TO REMAIN OFFSHORE THROUGH THU EVENING BEFORE DRIFTING IT EAST. 500MB PATTERN BUILDS RIDGE OVER NORTHERN MEXICO/SOUTHWEST U.S. CONTRIBUTING TO DRY FCST. WINDS SHIFT TO MORE NORTHEASTERLY BY THU AS SFC HIGH BEGINS DRIFTING EAST FROM TX PANHANDLE. 12Z MAV TEMPS SIGNIFICANTLY LOWER THAN MET...WILL LEAN MORE TOWARDS MET TEMPS DUE TO VERIFICATION ON 06Z RUN THE FACT THAT MAV IS FCSTING BKN TO OVC SKIES FOR THURSDAY. && .LONG TERM...MODEL GUIDANCE INDICATES WINDS WILL PICK UP A MORE EASTERLY COMPONENT ON FRI. WILL INTRODUCE LOW ISOLD POPS AS A WEAK SEABREEZE FRONT MAY TRIGGER SOME ACTIVITY. MODELS SHOW UPPER LEVEL PATTERN CHANGES LITTLE THROUGH THE FCST. SOME LOW AMPLITUDE TROFS MOVE QUICKLY ACROSS THE NORTHERN TIER STATES BUT DO LITTLE TO CHANGE A HIGHLY ZONAL FLOW THROUGH THE FCST. WILL KEEP SEABREEZE ACTIVITY THROUGH THE FCST AS ZONAL FLOW DOES NOT PROVIDE ENOUGH SUPPORT FOR EITHER FRONT TO REACH AS FAR AS SOUTH CENTRAL TX. && .MARINE...A FRONT HAS MOVED SOUTH OF THE DEEP SOUTH TEXAS AREA AND MODERATELY STRONG NORTH WINDS HAVE PUSHED IN ACROSS THE COASTAL WATERS. SEAS HAVE INCREASED SOMEWHAT...BUT THE WIND FLOW DOES NOT EXTEND IN A UNIDIRECTIONAL MANNER AND HAVE A SIGNIFICANT FETCH. THE CYCLONICALLY CURVED WINDS OVER THE NORTHWEST GULF ARE BEING PRODUCED BY A LOW PRESSURE CIRCULATION THAT FORMED ALONG THE FRONT AND IS CENTERED APPROXIMATELY 240 MILES EAST-NORTHEAST OF BROWNSVILLE. && .AVIATION...SKIES ARE MOSTLY CLEAR OVER THE LOWER RIO GRANDE VALLEY WITH MODERATELY STRONG NORTHERLY SURFACE WINDS. LOW PRESSURE OVER THE GULF SHOULD PRODUCE NORTH TO NORTHEAST WINDS AT LOCAL TERMINALS FOR AT LEAST THE NEXT 24 HOURS WITH MOSTLY CLEAR CONDITIONS. THE ONLY REAL FLY IN THE OINTMENT IS THE SLIGHT CHANCE FOR COASTAL TROUGHING TO DEVELOP AND CARRY SHOWER/THUNDERSTORM ACTIVITY INLAND OVER BRO/HRL...OTRW OUTSTANDING FLYING WEATHER. && .BRO WATCHES/WARNINGS/ADVISORIES...NONE && $$ SYNOPTIC/GRIDS...55 MARINE/AVIATION...69 MESO...VEGA THIS PRODUCT IS ALSO AVAILABLE ON OUR INTERNET WEB PAGE AT: HTTP://WWW.SRH.NOAA.GOV/BRO tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 143 AM MDT THU SEP 9 2004 .DISCUSSION...FORECAST PROBLEMS WILL BE HIGH TEMPERATURES AND BEING WATCHFUL OF PRECIPITATION GRAZING NORTHERN PORTION OF THE FORECAST AREA. SATELLITE SHOWING A FLAT ZONAL FLOW FROM THE PACIFIC INTO NORTH AMERICA. WITH THE MAIN STORM TRACK SO FAR NORTH IT ALMOST LOOKS LIKE SUMMER INSTEAD OF ONLY TWO WEEKS FROM FALL. WEAK WAVE IS MOVING ACROSS TO THE NORTH. THIS AND JUST ENOUGH MOISTURE AND INSTABILITY ALLOWED ISOLATED THUNDERSTORMS TO DEVELOP JUST NORTH OF US. AIR MASS CONTINUES TO GRADUALLY WARM AS LEE TROUGH REMAINS IN PLACE. AT JET LEVEL...MODELS INITIALIZED WELL. AT MID LEVELS...GFS SEEMED TO DO BETTER. BUT WITH SO MANY WAVES IN THE FLOW...MODELS WILL HAVING TIMING AND INTENSITY DIFFERENCES. THE GFS DID HAVE THE SOUTHWESTERN RIDGE AND HIGHER HEIGHTS TOO FAR EAST THOUGH. GFS LOOKS TOO MOIST IN THE 700 TO 500 MB LAYER COMPARED TO ANALYSIS AND SATELLITE. CONSIDERING TRENDS THROUGH 06Z AND WESTERLY FLOW ALOFT THE ETA LOOKS BETTER IN THIS AREA. AT LOW LEVELS...ETA IS DOING MUCH BETTER JOB ON LOCATIONS OF FEATURES AND THE WIND FIELD. THIS IS ESPECIALLY TRUE OF THE LEE TROUGH IN WHICH THE ETA/MET MOS/RUC HAVE BEEN DOING A SUPERIOR JOB. ALSO IS DOING BETTER ON 850 MB TEMPERATURES FROM OUR AREA INTO THE NORTHERN PLAINS. THINK HEIGHT FIELD AND FEATURES BEST REPRESENTED BY THE UKMET. GFS/UKMET FASTER WITH NORTHERN STREAM FEATURES AND LOOKS GOOD. WILL FOLLOW THE ETA MOISTURE AND LOW LEVEL FIELDS AS WELL. FOR TODAY/TONIGHT...GFS WANTS TO PUT A WEAK LEFT FRONT QUADRANT OF SOUTHERN JET INTO AREA LATE IN THE NIGHT. ETA HAS JET FURTHER SOUTH. SHORTWAVES ALSO COME THROUGH. GFS LOOKS TO BE SUFFERING FROM CONVECTIVE FEEDBACK AND TOO STRONG WITH INCOMING WAVES. ALSO HEIGHTS RISE OR STAY ABOUT THE SAME THROUGH THE NIGHT. HAVE COMPARED MODELS TO WHERE LAST TWO NIGHTS OF ISOLATED PRECIPITATION HAVE BEEN. AND THOSE PARAMETERS FAVOR KEEPING ANY PRECIPITATION TO THE NORTH OF AREA. GUIDANCE IS SIMILAR FOR TODAY AND WILL STAY CLOSE TO. FOR FRIDAY/FRIDAY NIGHT...GFS KEEPS SOME LINGERING JET DYNAMICS AROUND THROUGH THE DAY WITH ETA LESS FAVORABLE. HEIGHTS RISE AS WELL. CONSIDERING GFS DOWNFALLS WILL KEEP DRY. LITTLE TO NO DYNAMICS AND RISING HEIGHTS KEEP CONDITIONS DRY INTO THE NIGHT. PREFRONTAL WARMING AND DOWNSLOPE WINDS WILL MAKE FOR A WARM DAY. PLAN ON GOING CLOSER TO THE ETA TEMPERATURE FORECAST. FOR SATURDAY/SATURDAY NIGHT...HEIGHTS CONTINUE TO RISE WITH MAIN DYNAMICS AND STORM TRACK MUCH FURTHER NORTH SO WILL KEEP DRY. QUESTION WILL HIGH TEMPERATURES AS BOUNDARY MOVES IN FROM THE NORTH. GFS LOOKS TOO STRONG WITH UPPER SYSTEM MOVING ACROSS THE NORTHERN PLAINS. ALSO HAVE RISING HEIGHTS AND WESTERLY FLOW ALOFT. GFS ALSO LOOKS TO HAVE TOO MUCH MID AND UPPER LEVEL MOISTURE. ALL THIS LOOKS TO MAKE THE COOLING ADVERTISED BY THE GFS FOR SATURDAY TO BE TOO MUCH. DO LOOK TO HAVE AN UNFAVORABLE SURFACE WIND FIELD DESPITE THE LACK OF COOLING...SO WILL NOT GO TOO FAR ABOVE THE GFS. NO CHANGES PLANNED IN THE 4 TO 7 PERIOD AT THIS TIME. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ BULLER ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 430 AM EDT THU SEP 9 2004 .SHORT TERM (TODAY AND TONIGHT)... WIDESPREAD RAIN WITH EMBEDDED HEAVY TROPICAL DOWNPOURS CONTINUES EARLY THIS MORNING ACROSS THE REGION. KBOX-88D VWP INDICATING GOOD OVERRUNNING SETUP IN PLACE...WITH LOW LEVEL NORTHEAST FLOW VEERING TO MID LEVEL SOUTHWEST FLOW. RAIN BAND ACROSS CENTRAL MA EXTENDING EAST INTO BOSTON AT 4 AM...BEING ENHANCED BY STRONG SURFACE CONVERGENCE VICINITY OF QUASI STATIONARY BOUNDARY ALONG I-84 AND I-90 CORRIDOR. BOTH THE ETA-12 AND RUC HAVE A GOOD HANDLE ON THIS LOW LEVEL FEATURE...AND MOVE THIS BOUNDARY NORTHWARD INTO CENTRAL NEW ENGLAND BY EARLY THIS AFTERNOON. THUS...THINKING THE HEAVIEST RAINFALL WILL BE THIS MORNING INTO MIDDAY. FARTHER WEST...SURFACE LOW WHICH WAS ONCE FRANCES IS NEAR PITTSBURGH AT 4AM. MODELS IN GOOD AGREEMENT WITH TRACKING THIS CIRCULATION ACROSS WESTERN NY STATE TODAY AND THEN INTO NORTHERN NEW ENGLAND TONIGHT. SO EXPECTING EXCESSIVE RAINS TO REMAIN ACROSS THOSE AREAS. HERE IN SOUTHERN NEW ENGLAND...AS PREVIOUS SHIFTS HAVE STATED...FLASH FLOOD GUIDANCE IS HIGH...SO RIVERS AND STREAMS WILL REMAIN WITHIN THEIR BANKS. HOWEVER...URBAN/POOR DRAINAGE FLOODING WILL BE A CONCERN. SO WILL CONTINUE WITH FLOOD WATCH FOR HARTFORD COUNTY. OTHER CONCERN FOR TODAY WILL BE RISK OF STRONG THUNDERSTORM WINDS IF LOW LEVELS ARE ABLE TO DESTABILIZE. LOW AND MID LEVEL WIND FIELD INCREASE TO 50 KT THIS AFTERNOON. ANY DESTABILIZATION WILL INCREASE THE RISK OF STRONG THUNDERSTORM WINDS. HOWEVER...MODEL CROSS SECTIONS SUGGEST COLUMN REMAINS FULLY SATURATED THROUGH DAY...LIMITING LOW LEVEL INSTABILITY. ALTHOUGH...CAN/T RULE OUT AN ISOLATED THUNDERSTORM WITH STRONG WINDS...HOWEVER AT THIS TIME DOES NOT APPEAR TO BE WIDESPREAD OR EVEN SCATTERED. THUS...WILL HOLD OFF ON ISSUING AN SPS AND LET DAYSHIFT MONITOR HOURLY TRENDS. AS FOR THE HIGH SURF...WILL CANCEL ADVISORY AS IT APPEARS BUILDING SEAS TODAY WILL BE MORE WIND WAVE DRIVEN THAN SWELL...LESSENING THE POTENTIAL FOR LARGE SURF AND RIP CURRENTS NEAR SHORE. SWITCHED RADAR INTO TROPICAL Z/R MODE TO HOPEFULLY BETTER CAPTURE RAINFALL TOTALS. DEFAULT Z/R WAS SIGNIFICANTLY UNDERESTIMATING RAINFALL AMOUNTS. .LONG TERM (FRIDAY THROUGH NEXT WEDNESDAY)... COLD FRONT GRADUALLY DEPARTS THE SOUTHEAST PORTION OF THE FORECAST AREA BY MIDDAY FRIDAY...THEN IS EXPECTED TO STALL JUST SOUTHEAST OF THE COASTAL WATERS AS IT ENCOUNTERS THE 500 MILLIBAR RIDGE. WEAK HIGH PRESSURE WILL BUILD OVER THE REGION FRIDAY NIGHT AND SATURDAY. THE GFS BRINGS IN SLIGHTLY DRIER DEWPOINT AIR THAN THE ETA FRIDAY NIGHT AND SATURDAY... THOUGH THE ETA PUSHES THE FRONT SLIGHTLY FURTHER OUT TO SEA THAN THE GFS. ANOTHER SHORT WAVE IS EXPECTED TO TRAVEL ALONG THIS FRONTAL BOUNDARY SATURDAY NIGHT AND SUNDAY MORNING FROM THE NORTH CAROLINA COAST TO JUST SOUTHEAST OF THE FORECAST AREA BY DAYBREAK SUNDAY. THE GFS SNEAKS THIS SHORT WAVE ACROSS CAPE COD AND THE ISLANDS EARLY SUNDAY MORNING WHILE THE ETA LOSES TRACK OF THE SHORT WAVE. CAPE COD AND THE ISLANDS WILL BE UNDERNEATH THE FAVORABLE RIGHT REAR QUADRANT OF THE UPPER LEVEL JET SUNDAY MORNING. IN ADDITION SOME MOISTURE CONVERGENCE SHOULD BE AVAILABLE FROM THE SURFACE TO 850 MILLIBARS. ADDED CHANCE POPS FOR THE CAPE AND ISLANDS LATE SATURDAY NIGHT AND SUNDAY MORNING. A STRONGER COLD FRONT CROSSING NEW YORK STATE SUNDAY MORNING WILL HELP PUSH THE OLD COLD FRONT OUT TO SEA. CONTINUED MENTION OF A CHANCE OF SHOWERS ALONG THE COLD FRONT SUNDAY AFTERNOON...BUT MAINLY OVER INTERIOR LOCATIONS. THE NOSE OF THE 850 THROUGH 700 MILLIBAR JETS CROSS MAINE WITH SPEED MAXIMUMS TRAILING BACK INTO WESTERN PORTIONS OF THE FORECAST AREA. COLD TOP CONVECTION NUMBERS RISE INTO THE MID TO UPPER TEENS...TOTAL TOTALS JUMP INTO THE MID 40S...AND K INDICES INTO THE UPPER 20S WITH SHOWALTERS NEAR PLUS 2. STABILITY PARAMETERS APPEAR MARGINAL FOR THUNDER THOUGH CANNOT TOTALLY RULE OUT THE POSSIBILITY. WILL NOT MENTION IN THE GRIDS/ZONES AT THIS TIME. HIGH PRESSURE WILL BRING COOLER AND DRIER AIR ON MONDAY... FOLLOWED BY A MODERATION IN TEMPERATURES DURING MIDWEEK. CURRENT LONG RANGE MODELS DO NOT HAVE A GOOD CONSENSUS ON IVAN AND DID NOT FEEL CONFIDENT ENOUGH TO CONSIDER ANY CHANGES TO DAY 7 PORTION OF THE FORECAST AT THIS TIME. MADE A FEW CHANGES TO THE GRIDS BUT OVERALL THE DATABASE LOOKS TO BE IN GOOD SHAPE. && .MARINE... IN THE SHORT TERM...WILL CAP WINDS TO AROUND 20 KT...WITH A FEW GUSTS TO 25 KT ON NORTH SIDE OF BOUNDARY IN NORTHEAST FLOW. WILL HOIST SCA FOR ROUGH SEAS SOUTH COASTAL WATERS WITH PERSISTENT SOUTHEAST AND THEN SOUTH FLOW. WINDS VEER TO SOUTHEAST LATER THIS MORNING AND THEN SOUTH THIS AFTERNOON. WINDS WILL THEN SHIFT TO SOUTHWEST TONIGHT. VSBY MAINLY 1 TO 3 NM IN RAIN AND FOG...THEN IMPROVING TO 3 NM OR BETTER ONCE WE WARM SECTOR AND TURN WINDS TO THE SOUTH AND SOUTHWEST. IN THE LONGER TERM...SOUTHERLY SWELL IS EXPECTED TO DECREASE BY SATURDAY AS THE COLD FRONT PASSES THROUGH THE WATERS. && .AVIATION... LOW CIGS WILL SLOWLY LIFT TODAY AS WINDS TURN SOUTH THIS AFTERNOON. WIDESPREAD MVFR LIKELY THIS AFTERNOON AND TONIGHT IN SOUTH TO SOUTHWEST FLOW. NO TAF FOR ACK PER MISSING VSBY. SHOULD BE B FIXED NEXT TUESDAY...HOWEVER TAF MAY RESUME FRI. IJD OTS FOR ANOTHER 10 DAYS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...FLASH FLOOD WATCH HARTFORD COUNTY THROUGH MIDDAY THU. MA...NONE. NH...NONE. RI...NONE. MARINE...SCA FOR ROUGH SEAS 235-237-254 AND 255. $$ .SHORT TERM...NOCERA .LONG TERM...STRAUSS ma AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 255 AM CDT THU SEP 9 2004 .DISCUSSION... FORECAST CHALLENGES REMAIN SMALL PRECIP CHANCES/ELEVATED CONVECTION WITH MINOR SHORTWAVES IN NW FLOW IN THE PRESENCE OF STEEP LAPSE RATES...WAA...AND LIMITED MOISTURE INTO THE WEEKEND...FRONTAL PASSAGES FRIDAY NIGHT INTO SUNDAY NIGHT AND ASSOCIATED WEATHER...THEN EFFECT OF APPROACH OF A BROADER MID LEVEL TROF SUNDAY NIGHT INTO WEDNESDAY...TEMPS DURING THE PERIOD. POTENTIAL FOR FOG THIS AM. THE LATEST SFC ANALYSIS HAD HIGH PRESSURE FROM WI THRU IA INTO KS...WITH LOW PRES OVR SD...NE CO AND SE MT. SFC FLOW WAS LIGHT SE WITH TEMPERATURES IN THE 50S AND DEWPOINTS IN THE 50S. THE WATER VAPOR STLT WITH THE LIGHTNING AND H5 RUC ANALYSIS OVERLAID DEPICTED A SHORTWAVE IN THE WESTERLY FLOW MOVING ACRS SD AND NEB. THIS WAVE WAS TOUCHING OFF A COUPLE OF AREAS OF WEAK CONVECTION. THE LOW LEVEL JET IS STRONG DURING THE EARLY MORNING HRS...AT 40KT NR ONL...WITH THE THETA E/WAA FOCUSING ACRS NRN NEB INTO SD. AGAIN...FORECAST SOUNDINGS SHOW STEEP MID LEVEL LAPSE RATES AND SOME...ALBEIT LIMITED RH. THE SHORT RANGE MODELS ARE MAINLY DRY THRU MIDNIGHT FRIDAY...WITH SOME CHANCE PRECIP WITH THE FRONTAL PASSAGE FRIDAY NIGHT INTO SAT. INCLUDED ISOLATED -TSRA N TODAY AND SLIGHT CHANCE POPS NE TON WITH UVV AND THETA-E ADV AND POSITIVE CAPES FROM 500 TO 1000 J/KM N...SOME -TSRA MAY BE ENOUGH FOR ELEVATED CONVECTION. SWODY1 MENTIONS NW IN GENERAL THUNDER TODAY. NOTE SHEAR VALUES OF 40KT FROM 0-6KM MUCH OF CWA TAF. EARLY THIS AM...MAY INCLUDE SOME MENTION OF FOG PARTS OF ERN NEB AND WRN IA. SOME LOCATIONS DOWN TO TWO DEGREE SPREADS ALREADY WITH LIGHT OR CALM WINDS. HIGHS WEDNESDAY WERE MAINLY 75 TO 80 WITH A FEW LOWER 70S FOR SOUTHWEST IOWA. THIS AFTERNOON EXPECT WARMER TEMPERATURES WITH STRONGER SOUTH FLOW AND HIGH H850 TEMPS. AFTERNOON RANGE FROM AROUND 80 SW IA TO UPR 80S MUCH OF THE WRN COUNTIES IN THE FCST AREA. LOWS TONIGHT MOSTLY 57 TO 62. SOUTH FLOW INCREASES EVEN FURTHER FOR FRIDAY AND HAVE HIGHS 85 TO 90...EXCEPT IN SW IA. RE-INTRODUCED SMALL POPS NW FRIDAY NIGHT...AND SPREAD SMALL POPS FARTHER SE ACRS ALL BE THE SE PORTION OF THE FCST AREA WITH THE SURFACE FRONT. COLD ADVECTION NOT REAL STRONG...THUS HAVE HIGHS 80 TO 85. DURING THE EXTENDED PERIOD...THE FRONT LIFTS BACK NORTH SUN AS THE SFC RIDGE SLIDES TO THE EAST AND A LOW PRESSURE TROF DEVELOPS OVER THE WRN PLAINS. THE TROF BECOMES MORE OF A PROMINENT FEATURE MONDAY...STRETCHING FROM THE DAKOTAS INTO NEBRASKA AND WRN KS. THIS FRONT REMAINS IN THE VICINITY THROUGH THE EXTENDED. PRECIPITABLE WATER VALUES POOL NEAR THE FRONT IN EXCESS OF 1.5 INCHES. LOOKS UNSETTLED FOR THE UPPER MISSISSIPPI VALLEY INTO THE DAKOTAS DURING THIS PERIOD...FARTHER SOUTH FOR OUR FORECAST AREA...PRECIPITATION CHANCES HIGHER IN THE N CLOSER TO THE MAIN SYNOPTIC FEATURES. SHOULD BE SOME ADDITIONAL JET SUPPORT MON NIGHT INTO TUE. GFS HAS SHOWN SOME AMPLITUDE CHANGE AND IS A LITTLE FLATTER WITH THE 00Z RUN AND IS CLOSE TO THE UKMET AND ECMWF. GFS POPS TUE THRU THU IN THE 20-40 RANGE MON THRU THU...CLIMATOLOGY IS AROUND 25. TEMPS STILL ABOVE NORMAL. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ ZAPOTOCNY ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 345 AM CDT THU SEP 9 2004 .SHORT TERM...SHORT RANGE GUIDANCE INDICATES PERSISTENT SURFACE TROFFING OFFSHORE OF THE LOWER TX COASTLINE. RADAR REFLECTIVITY INDICATES THAT THIS FEATURE IS GENERATING CONV OVER THE OFFSHORE WATERS THIS MORNING. THE BIGGEST DIFFERENCES IN THE MODEL GUIDANCE CONCERNS THE MEAN RH FIELD ALIGNMENT. ETA AND GFS ARE MORE AGGRESSIVE IN RETURNING MOISTURE LEVELS OVER DEEP SOUTH TX WHILE THE RUC IS A LITTLE SLOWER WITH THE OVERALL REBOUND OF THE MOISTURE. THE 00Z BRO SOUNDING SHOWED A FAIRLY DRY AND STABLE AIRMASS IN PLACE OVER THE REGION WED EVENING AND THE CURRENT BRO VWP SHOWS NORTHERLY FLOW FROM THE SURFACE EXTENDING FROM THE SURFACE UP TO AROUND 8 KFT WITH NE WINDS EVIDENT AT AROUND 10 KFT. BOTH THE GFS AND THE ETA MOISTURE FIELDS ARE PROBABLY A BIT OVERDONE WHICH RESULTS IN VERY HIGH POPS IN BOTH THE MAV AND MET GUIDANCE. HOWEVER...BELIEVE THAT THE NE LOW LEVEL FLOW WILL BE FAIRLY QUICK TO RETURN WHICH WILL RESULT IN LOW LEVEL MOISTURE CONV NEAR THE COASTLINE INCREASING POPS HERE. ACCORDINGLY...WILL INCREASE POPS MAINLY OFFSHORE AND ALONG THE COASTAL AREAS OVER THE NEXT COUPLE OF DAYS. LATER IN THE FORECAST PERIOD...5H RIDGING BUILDS IN OVER THE BORDER REGION WHICH WILL ONCE AGAIN DRY OUT THE ATMS OVER THE REGION DIMINISHING RAIN CHCS. WITH THE VERY WET MAV AND MET FORECAST POPS...THE GUIDANCE HIGHS FROM BOTH MODELS APPEAR TO BE A BIT LOW SO WILL GO WITH HIGHS ABOVE MAV AND MET VALUES. && .LONG TERM...GFS AND ECMWF MODELS MAINTAINS 5H RIDGING OVER THE WESTERN GULF COAST AND THE TEX/MEX BORDER REGION. THE GFS IS DRIER THAN THE ECMWF WITH THE ECMWF MAINTAINING DECENT MOISTURE VALUES INTO NEXT WEEK. BELIEVE THAT THE ECMWF HIGH MOISTURE VALUES ARE A BIT OVERDONE DUE TO THE ECMWF OVERDEVELOPING A SURFACE LOW OVER THE BAY OF CAMPECHE. OVERALL...WILL GO WITH THE DRIER GFS SOLUTION WITH TEMPS NEAR OR ABOVE CLIMO. LATEST DISC FROM TPC INDICATES THAT LONGER RANGE GUIDANCE IS PRETTY CONSISTENT IN MOVING NOW CAT 5 IVAN INTO THE EASTERN GULF OF MEX LATER THIS WEEKEND AND INTO MON. && .MARINE...AT 1 AM BUOY 020 REPORTED NORTH-NORTHEAST WINDS AT 16 KNOTS WITH GUSTS TO 18 KNOTS AND SEAS AT 4 FEET WITH A 5 SECOND PERIOD. A SURFACE AND UPPER LEVEL HIGH PRESSURE RIDGE WILL PREVAIL OVER THE COASTAL WATERS OF DEEP SOUTH TEXAS THROUGH THE WEEKEND PRODUCING LIGHT TO MODERATE NORTH TO NORTHEAST WINDS. A WEAK LOW PRESSURE TROUGH OFF THE COAST OF TEXAS MAY GENERATE A FEW SHOWERS AND ISOLATED THUNDERSTORMS OVER THE MARINE AREAS THROUGH SATURDAY. MODERATE NORTHEAST WINDS AND SEAS IN THE 3 TO 5 FEET RANGE WILL PREVAIL OVER THE COASTAL WATERS THROUGH THE WEEKEND. SEAS MAY INCREASE SLIGHTLY OVER THE COASTAL WATERS EARLY NEXT WEEK. && .AVIATION...VFR CONDITIONS WITH CLEAR SKIES AND LIGHT NORTHWESTERLY WINDS ARE BEING REPORTED AT THE REGIONAL AIRPORTS OF DEEP SOUTH TEXAS. A SURFACE AND UPPER LEVEL HIGH PRESSURE RIDGE WILL PREVAIL OVER DEEP SOUTH TEXAS TODAY PRODUCING LIGHT TO MODERATE NORTHERLY WINDS AND MOSTLY CLEAR TO PARTLY CLOUDY SKIES OVER CWA. A WEAK LOW PRESSURE TROUGH OFF THE COAST OF TEXAS MAY GENERATE A FEW SHOWERS OVER THE AREA TODAY REDUCING CEILINGS TEMPORARILY TO MVFR CONDITIONS. OTHERWISE VFR CONDITIONS WILL PREVAIL OVEN THE REGIONAL AIRPORTS OF DEEP SOUTH TEXAS DURING THE NEXT 24 HOURS. && .BRO WATCHES/WARNINGS/ADVISORIES...NONE && $$ SYNOPTIC/GRIDS...60 MARINE/AVIATION/MESO...63 THIS PRODUCT IS ALSO AVAILABLE ON OUR INTERNET WEB PAGE AT: HTTP://WWW.SRH.NOAA.GOV/BRO tx EAST CENTRAL FLORIDA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 1002 AM EDT THU SEP 9 2004 .DISCUSSION... VERY MOIST AIR MASS IN PLACE ACROSS THE CENTRAL PENINSULA WITH MORNING SOUNDINGS SHOWING PRECIPITABLE WATER VALUES EXCEEDING 2.25 INCHES. CHECKED THE GPS PRECIP WATER SITES AND THEY ALSO SUPPORT THESE HIGH VALUES. THIS SHOULD SUPPORT THE EARLY DEVELOPMENT OF SHOWERS AND STORMS. ONE FLY IN OINTMENT THAT MAY LIMIT COVERAGE SOMEWHAT IS DEBRIS CLOUDS FROM CLUSTER OF CONVECTION ALONG THE WEST CENTRAL COAST. LOW LEVEL RIDGE BUILDING INTO THE CENTRAL PENINSULA WILL WEAKEN THE SOUTHWEST STEERING FLOW SO STORMS WILL BE SLOW MOVING AND THERE DEFINITELY IS THE THREAT OF FLOODING WITH THE STRONGER STORMS... ESPECIALLY OVER THE INTERIOR AND NORTH COASTAL AREAS WHERE IT HAS BEEN THE WETTEST THE LAST FEW MONTHS. THE EAST COAST SEA BREEZE WILL ACT TO PROVIDE ADDITIONAL LIFT FOR STORMS TODAY SO A FEW COULD BE STRONG AND PRODUCE FREQUENT LIGHTNING AND WIND GUSTS UP AROUND 50 MPH. ANY STORMS INITIATING CLOSE TO THE COAST ON THE SEA BREEZE THIS MORNING OR EARLY AFTERNOON COULD ALSO SPAWN A WATERSPOUT WITH SUCH LIGHT LOW LEVEL WINDS AND HIGH MOISTURE IN THE ATMOSPHERE. DO NOT SEE ANYTHING THAT REALLY NEEDS ADJUSTMENT IN THE FORECAST OR HAZARDOUS WEATHER OUTLOOK. && .MARINE...SURE DO MISS BUOY 009. BUOY 010 WAS RECORDING SOUTHERLY WINDS AT 10 TO 12 KNOTS AND 5 FOOT SEAS. LATEST RUC RUN WAS INDICATING SURFACE RIDGE SHIFTING NORTH DURING THE DAY RESULTING IN A SOUTHEASTERLY FLOW LATER TODAY. CURRENT MARINE GRIDS ARE TRENDING TOWARD THAT DIRECTION AND LOOK GOOD FOR NOW. && .MLB WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC...LASCODY MARINE...WIMMER fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1144 AM EDT THU SEP 9 2004 .UPDATED... I DID A QUICK UPDATE TO AFTERNOON FORECAST TO GO WITH MOSTLY SUNNY SKIES ACROSS THE CWA (WE HAD PARTLY CLOUDY). OVER THE SE SECTIONS OF THE CWA...SKIES AT 11 AM WERE PARTLY TO MOSTLY CLOUDY SINCE AS YET THE SHALLOW MOISTURE (AS PER THE 12Z DTX SOUNDING SHOWING DECENT MOISTURE BELOW 5000FT) HAD NOT MOVED OUT. HOWEVER...THE RUC AND ETA (ETA NOT AS STRONGLY AS THE RUC) SUGGESTS DRIER AIR FROM THE NORTH WILL MOVE SOUTH ACROSS THE CWA (APX 12Z SOUNDING). IT WOULD NOT SURPRISE ME IF MOST OF THE GRR CWA DID BRIEFLY BECOME PARTLY CLOUDY BETWEEN 17Z AND 19Z BUT AFTER 19Z ENOUGH DRY AIR MOVES IN THAT WHATEVER CU IS OUT THERE SHOULD START DISSIPATE. SO EVEN IF WE GET 2 HOURS OF PARTLY CLOUDY SKIES THE OVERALL ASPECT OF THIS AFTERNOON IN SOUTHWEST MICHIGAN WILL BE MOSTLY SUNNY. OTHERWISE THE ON GOING FORECAST IS FINE. && .GRR WATCHES/WARNINGS/ADVISORIES...NONE. $$ WDM mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1012 AM EDT THU SEP 9 2004 .DISCUSSION... SFC RIDGE ACROSS THE UPPER GREAT LAKES IS THE DOMINANT FEATURE REGARDING TODAY'S WEATHER. WINDS WILL BE LIGHT (GENERALLY LAKE- DRIVEN) AND DRY AIRMASS IN PLACE SHOULD SUPPORT ONLY SCATTERED AFTN CUMULUS AT BEST. SOME MID CLOUD SPREADING INTO THE WRN U P... ASSOCIATED WITH A WEAK SHORTWAVE IN MN...WILL WORK INTO CENTRAL PARTS THIS AFTN. ONLY REAL FCST ISSUE TODAY IS TEMPS. ETA/RUC FCST SOUNDINGS HAVE GOOD HANDLE ON WARM LAYER FROM 800- 850MB SHOWN ON 12Z KGRB SOUNDING. MIXING TO NEAR 850MB (BASE OF INVERSION ON THE GRB SOUNDING) WOULD YIELD TEMPS OF NEAR 70F. GOING FORECAST OF 60S NEAR LAKE SUPERIOR TO LOWER 70S INLAND LOOKS FINE. NO UPDATE PLANNED AT THIS TIME. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ JKL mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MONTANA 900 AM MDT THU SEP 9 2004 UPDATE...ZONES AND GRIDS ALREADY UPDATED TO ACCOUNT FOR A PUSH OF CANADIAN AIR INTO MY NORTHWEST ZONES THIS MORNING. HIGH TEMPERATURES FOR TODAY HAVE BEEN DROPPED NEARLY 10 DEGREES IN THIS AREA. HAVE ALSO ADDED A MENTION OF MORNING SPRINKLES AND LOCALLY DENSE FOG...ALONG WITH NORTH WINDS. AS USUAL...LAST NIGHTS SHORT TERM FORECAST MODELS DID NOT BRING THE CANADIAN AIR FAR ENOUGH SOUTH. HOWEVER...THE 12Z RUN OF THE RUC MODEL WAS ABLE TO CAPTURE THIS PUSH AND BRINGS THE COOLER AIR ABOUT AS FAR SOUTH AS THE CONRAD AREA BEFORE SHUNTING IT TO THE SOUTHEAST. THIS SCENARIO APPEARS REASONABLE...BUT CAN NOT RULE OUT THE POSSIBILITY THAT THE COOLER AIR WILL MAKE IT AS FAR SOUTH AS GREAT FALLS. WILL KEEP A CLOSE EYE ON THE SITUATION AND MAKE FURTHER UPDATES IF NEEDED. FORECAST FOR THE REMAINDER OF MY CWA APPEARS TO BE ON TRACK AND DID NOT MAKE UPDATES TO ANY ZONES SOUTH OR WEST OF THE GREAT FALLS AREA. MPJ && .PREV DISCUSSION...ISSUED AT 324 AM MDT THU SEP 9 2004 TODAY AND TONIGHT...SATELLITE AND RADAR SHOWS AN AREA OF WEAK SHOWERS MOVING OUT OF FERGUS COUNTY. CLOUDS MOVING INTO NORTHWESTERN PORTION OF CWA IN RESPONSE TO UPPER LEVEL TROUGH MOVING OVER NORTHWESTERN WASHINGTON. SOUTHWEST WINDS WILL PICK UP ESPECIALLY ALONG THE ROCKY MOUNTAIN FRONT AS A JET STREAK MOVES OVER NORTHERN PORTION OF STATE. LOOKS LIKE BEST CHANCE OF SHOWERS OVER NORTHERN ROCKY MOUNTAIN FRONT THIS MORNING ESPECIALLY NEAR THE CANADIAN BORDER. SHOWERS AND AN ISOLATED THUNDERSTORM OVER SOUTHWESTERN ZONES IN THE AFTERNOON SPREADING OVER REST OF CWA TONIGHT AS A WEAK SHORT WAVE MOVES ALONG A LOW LEVEL CONVERGENCE ZONE MAINLY OVER THE SOUTHERN ZONES. FRIDAY AND FRIDAY NIGHT...SURFACE LOW SLIPS DOWN EASTERN MONTANA BRINGING MOISTURE AND SOME INSTABILITY. CLOUDS WILL INCREASE WITH WEAK FRONTAL PASSAGE. HAVE SOME PRECIPITATION MAINLY OVER NORTHERN ZONES WITH WARM FRONTAL PASSAGE. COOLED TEMPERATURES DOWN A LITTLE BUT WENT HIGHER THAN GUIDANCE. CAMP ON SATURDAY...EXPECT GUSTY WEST WINDS TO DEVELOP OVER THE REGION...AS A SURFACE AREA OF LOW PRESSURE MOVES EAST ACROSS CENTRAL ALBERTA. THIS WILL ALLOW TEMPERATURES TO AVERAGE BETWEEN 5 AND 10 DEGREES ABOVE NORMAL AS WELL. ON SATURDAY NIGHT...A COLD FRONT WILL MOVE SOUTH INTO THE REGION...BRINGING IN COOLER TEMPERATURES AND A CHANCE FOR SHOWERS. ON SUNDAY...EXPECT COOLER TEMPERATURES...ALONG WITH A CHANCE FOR SHOWERS AND THUNDERSTORMS...AS A SURFACE AREA OF LOW PRESSURE DEVELOPS OVER NORTHERN WYOMING. EXPECT THE SHOWERS TO EXIT THE AREA LATE SUNDAY NIGHT OR EARLY MONDAY...AS THE UPPER LEVEL PATTERN WILL SHIFT TO A BROAD TROF OVER THE ENTIRE PACIFIC NORTHWEST AND NORTHERN ROCKIES. THIS WILL ALLOW FOR A GRADUALLY COOLING TREND IN TEMPERATURES MONDAY THROUGH THURSDAY. ADDITIONALLY...THERE WILL BE A CHANCE FOR PRECIP ACROSS MUCH OF THE AREA TUESDAY THROUGH THURSDAY. SOME OF THE PRECIP WILL FALL IN THE FORM OF SNOW. HOWEVER...THE EXACT TIMING OF THE FRONTS... AND EXACTLY HOW COLD THIS AIRMASS IS GOING TO BE IS STILL A BIT UNCERTAIN. THEREFORE...BECAUSE THE SNOW ELEVATION IS STILL TOO UNCERTAIN...I WILL NOT MENTION SNOW AT THIS TIME...BUT CONTINUE TO MONITOR IT CLOSELY. BRUSDA && .PRELIMINARY POINT TEMPS/POPS... GTF BB 077/048 073/049 079 07020 BEBBE 052/071 044/065 044/063 041/064 040 00033122233 CTB FB 066/042 067/046 078 07122 NEBBE 049/069 043/059 043/058 040/056 037 00032112233 HLN BB 080/052 076/052 080 07120 BEBBE 051/076 046/066 046/067 042/068 042 00233222233 BZN BB 082/044 078/046 081 07110 BBBBB 047/078 042/069 042/070 039/068 039 00023222233 WEY BB 074/033 071/036 078 07010 BBBBW 039/071 034/071 034/067 027/068 026 00023222254 DLN BB 079/045 076/046 082 07110 UEBBE 047/076 042/069 042/067 041/068 038 00233212233 HVR BB 075/047 073/047 079 07022 BEBBB 051/076 046/066 046/062 043/063 040 00033122233 LWT BB 077/047 071/047 081 07020 BBBBB 047/075 042/067 042/063 039/064 036 00014223333 && .TFX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ mt AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MORRISTOWN TN 948 AM EDT THU SEP 9 2004 .DISCUSSION...ABUNDANT LOW LEVEL MOISTURE LINGERS...ESPECIALLY OVER NE TWO THIRDS OF THE FORECAST AREA WHERE RUC AND ETA MODELS INDICATE AT LEAST A BROKEN CLOUD DECK WILL LAST INTO THE AFTERNOON HOURS. A FEW AREAS HAVE SCATTERED OUT WHERE SOME WEAK DOWN SLOPING IS OCCURRING...SUCH AS CHEROKEE/CLAY COUNTIES AND VALLEY SPOTS. AREA RADARS SHOW VERY LITTLE MEASURABLE PCPN...ALTHO A FEW PATCHES OF DRIZZLE MAY STILL BE FALLING. JUST GOT A REPORT OF SOME LIGHT RAIN AT MT LECONTE...WHERE WEAK UPSLOPE MAY BE HELPING TO SQUEEZE OUT PCPN. WILL NEED TO UPDATE IN A BIT TO REMOVE THE MORNING WORDING...AND I MAY KEEP SOME MENTION OF DRIZZLE WHERE THE LOW LEVEL MOISTURE IS GREATEST AND WEAK UPSLOPE DUE TO NW LOW LEVEL WINDS IS A FACTOR. && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ TG tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 321 PM EDT THU SEP 9 2004 .DISCUSSION... MAIN CONCERN IS NEXT SYSTEM FOR FRIDAY NIGHT AND SATURDAY CURRENT WEATHER...18Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED RIDGING ALONG THE EAST COAST WITH THE REMNANTS OF FRANCES MOVING UP THROUGH THE HUDSON VALLEY...THEN SOUTHWEST FLOW FROM THE PACIFIC NORTHWEST TO NORTHERN QUEBEC. WITHIN THIS FLOW...SHRTWVS WERE LOCATED OVER SOUTHERN MANITOBA TO CENTRAL NORTH DAKOTA...ONE OVER SOUTHERN ALBERTA...AND ANOTHER NEAR VANCOUVER ISLAND ASSOCIATED WITH AN UPPER TROUGH. A FEW LIGHTNING STRIKES HAVE OCCURRED WITH THE SHRTWV OVER SOUTHERN MANITOBA. TOWARDS HOME...OTHER THAN SOME DIURNAL CUMULUS...IT HAS BEEN A PLEASANT DAY WITH HIGH PRESSURE EXTENDING FROM NORTHERN ONTARIO TO MISSOURI. A SURFACE LOW WAS LOCATED NEAR RAPID CITY WITH A WARM FRONT EXTENDING FROM PIERRE TO THE TWIN CITIES. ALONG AND SOUTH OF THIS FRONT...850MB TEMPS AT 12Z WERE 20 AT ABERDEEN...18 AT OMAHA AND 21 AT NORTH PLATTE PER RAOBS (APPROXIMATELY 8C OVER THE U.P.). TONIGHT...AS THE TROUGH DIGS MORE INTO THE PACIFIC NORTHWEST... SLIGHT RIDGING BUILDS ACROSS THE PLAINS. THIS RESULTS IN THE WARM AIR AT 850MB OVER THE PLAINS TO BE PUSHED NORTHEASTWARD...WITH THE 850MB WARM FRONT IN THE VICINITY OF NORTHERN WISCONSIN FRIDAY MORNING. ETA CONTINUES TO SHOW AN AREA OF ENHANCED OMEGA ASSOCIATED WITH ISENTROPIC LIFT/THETA-E ADVECTION WITH THIS WARM FRONT...ALONG WITH DPVA ASSOCIATED WITH THE SHRTWV OVER SOUTHERN MANITOBA MOVING INTO WESTERN ONTARIO. HOWEVER...ETA SOUNDINGS WITHIN THIS AREA OF OMEGA SHOW DRY AIR BELOW 700MB (WITH DEWPOINT DEPRESSIONS ON THE ORDER OF 10 TO 16C) WHICH PREVENTS ANY PRECIPITATION. THE ISENTROPIC LIFT COMBINED WITH DPVA FROM THE SHRTWV WILL AID IN THE DEVELOPMENT OF A MID-CLOUD DECK FROM THE WARM FRONT TO THE SHRTWV. THESE MID-CLOUDS CAN ALREADY BE SEEN OVER EASTERN NORTH DAKOTA. ALTHOUGH THERE IS CURRENTLY LIGHTNING PRESENT...SOUNDINGS SHOW THE ELEVATED INSTABILITY DECREASING AS IT APPROACHES UPPER MICHIGAN. SO THERE WILL BE NO MENTION OF DRY THUNDERSTORMS IN THE FORECAST. TEMPS WILL FALL QUICKLY THIS EVENING OVER THE CENTRAL AND EASTERN SECTIONS OF THE CWA WITH LIGHT WINDS. ADDED SOME PATCHY FOG IN SINCE THE GROUND STILL REMAINS MOIST...ESPECIALLY OUT IN THE EAST WHERE THERE ARE SWAMP AREAS. AS THE HIGH PRESSURE RIDGE GRADUALLY SHIFTS EAST OVERNIGHT...SOUTHEASTERLY WINDS WILL BEGIN TO PICK UP (WHICH WERE PRESENT OVER NORTHWEST WISCONSIN THIS EVENING) OVER THE CENTRAL SECTIONS. HOWEVER...IT LOOKS LIKE THE EASTERN U.P. WILL STAY DECOUPLED ALMOST TO SUNRISE. THIS MEANS A WIDE RANGE OF TEMPERATURES...RANGING FROM THE MID 50S OVER THE FAR WEST TO AROUND 40 IN THE EAST. FRIDAY...SHRTWV TROUGH OVER THE PACIFIC NORTHWEST CONTINUES EASTWARD INTO NORTH DAKOTA BY 00Z. WARM AIR ADVECTION OUT AHEAD OF THE LOW PRESSURE SYSTEM IN SOUTH DAKOTA WILL HELP PUSH 850MB TEMPS TO 14-16C BY 18Z. ANOTHER WARM FRONT FORMS ASSOCIATED WITH THIS LOW OVER SOUTHERN MN/WI...BUT LITTLE ACTIVITY IS EXPECTED WITH IT AS THE AIR IS CAPPED (850MB TEMPS OF 20C WITH DEWPOINTS ONLY IN THE UPPER 50S). SO AFTER THE MID-CLOUD PASSES IN THE MORNING...TEMPS WILL RISE QUICKLY. FOR NOW WILL UP HIGHS TO NEAR 80 OVER THE WEST HALF OF THE U.P. WHERE WINDS TURN SOUTHWESTERLY. COOLER TEMPS ALONG LAKE MICHIGAN WITH THE FLOW OFF THE LAKE. FRIDAY NIGHT INTO SATURDAY...STILL SOME UNCERTAINTY HOW THIS SHRTWV TROUGH AND THE ASSOCIATED LOW PRESSURE SYSTEM MOVE THROUGH THE UPPER MISSISSIPPI VALLEY. THE ETA IS NOW THE FASTEST WITH THE SYSTEM...WHICH SEEMS SOMEWHAT REASONABLE GIVEN THE PROGRESSIVE NATURE OF THE FLOW BUT IT MIGHT BE TOO FAST. GFS IS A LITTLE SLOWER...BUT AT 12Z SATURDAY THE SURFACE LOW IS OVER NORTHERN ONTARIO AND INFLUENCED BY CONVECTIVE FEEDBACK. THE UKMET AND CANADIAN REMAIN THE SLOWEST HAVING THE SYSTEM BACK NEAR INTERNATIONAL FALLS AT THE SAME TIME. 09Z SHORT-RANGE ENSEMBLES ALSO INDICATE A SIMILAR SPREAD IN POSITIONS. THE 06Z ETA LOOKS LIKE A GOOD COMPROMISE AND WILL FOLLOW FOR FORECAST. SURFACE LOW OVER SOUTH DAKOTA MOVES NORTHEAST TO NORTHERN LAKE SUPERIOR BY 12Z SATURDAY AND TO THE SOUTHEASTERN END OF JAMES BAY BY 00Z SUNDAY. WITH THE WARM FRONT FROM SOUTHERN MN/WI MOVING NORTH AND THE NOCTURNAL LOW-LEVEL JET STRENGTHENING...SOME STORMS MAY FIRE ALONG IT AND MOVE THROUGH THE U.P. (LIKE THE 12Z ETA SUGGESTS). UPPER DIVERGENCE FROM THE RIGHT REAR QUADRANT OF A 70KT 250MB WINDSPEED MAX MOVING INTO WESTERN ONTARIO WILL ALSO AID IN THE DEVELOPMENT OF STORMS. WILL THROW IN A 30 PERCENT CHANCE FOR THIS. THEN AS THE COLD FRONT MOVES THROUGH ON SATURDAY...EXPECT ANOTHER CHANCE FOR SHOWERS AND THUNDERSTORMS. ONE THING TO NOTE IS THAT THE QPF FROM THE 12Z GFS HAS REALLY DROPPED WITH THIS FRONT...AND THE ETA DOES NOT HAVE MUCH QPF EITHER (DUE TO CAPPING ISSUES AND BEST DYNAMICS HEADING INTO ONTARIO). AFTER THE FRONTAL PASSAGE...A STRATOCUMULUS WILL BEGIN MOVING SOUTH ACROSS THE LAKE WITH A DRY-SLOT INBETWEEN THIS DECK AND THE FRONT. SO EXPECT A DECENT PERIOD OF MIXING...WHICH WILL ALLOW HIGHER WINDS TO MIX DOWN. AN ISALLOBARIC PRESSURE RISE WILL ALSO AID IN SOME GUSTY WINDS...ESPECIALLY OVER THE KEWEENAW PENINSULA. TEMPERATURES WARM FRIDAY NIGHT UNDER THE SOUTHERLY FLOW...AND CONTINUE TO RISE UNTIL SATURDAY AFTERNOON WHEN THE FRONT CLEARS THE AREA AND 850MB TEMPS FALL TO 6-8C. SATURDAY NIGHT INTO SUNDAY...CONTINUING TO FOLLOW THE 06Z ETA SOLUTION...HIGH PRESSURE WHICH IS CURRENTLY OVER NORTHERN BRITISH COLUMBIA BEGINS NOSING DOWN INTO WESTERN LAKE SUPERIOR SATURDAY NIGHT AND OVER ALL OF LAKE SUPERIOR ON SUNDAY. MEANWHILE STRONG RETURN FLOW SETS UP OVER MINNESOTA ON SUNDAY AS UPPER LEVEL RIDGING BUILDS OUT THERE ALONG WITH THE DEVELOPMENT OF ANOTHER LOW PRESSURE SYSTEM IN THE DAKOTAS. STRATOCUMULUS CLOUD DECK WILL MOVE DOWN OVER THE U.P. SATURDAY NIGHT AND THEN SLOWLY MIX OUT SUNDAY MORNING. THIS DECK WILL HELP KEEP TEMPERATURES UP SATURDAY NIGHT...MUCH MORE THAN WHAT THEY WERE UNDER THE HIGH PRESSURE CENTER OVER NORTHERN BRITISH COLUMBIA (LOWS WERE IN THE MID TO UPPER 20S). STILL...WE SHOULD SEE TEMPS COOLER THAN FRIDAY NIGHT...MAINLY IN THE 40S. HIGHS ON SUNDAY WILL BE SEASONABLY COOL WITH 850MB TEMPS OF 6-8C. COOLEST READINGS OVER THE NORTHERN U.P. WHERE ENE WINDS BRING IN AIR OFF LAKE SUPERIOR. NOTE: SHOULD THE 12Z GFS OR UKMET TURN OUT...TEMPERATURES WILL BE WARMER OVER THE FAR WESTERN COUNTIES AND ALONG THE WISCONSIN BORDER. WILL WAIT UNTIL THESE MODEL DIFFERENCES RESOLVE THEMSELVES BEFORE MAKING ANY CHANGES TO TEMPS. SUNDAY NIGHT...THE TIMING OF WHEN THE RETURN FLOW ARRIVES IN THE U.P. WILL HAVE A MAJOR EFFECT ON TEMPERATURES. SINCE SKIES ARE PROGGED TO BE MOSTLY CLEAR...THE MAIN CONCERN IS TEMPERATURES. RIGHT NOW IT LOOKS LIKE THE RETURN FLOW WILL HIT THE WESTERN U.P. OVERNIGHT...SO WILL BUMP UP TEMPS THERE A FEW DEGREES. HOWEVER...THE EASTERN U.P. MAY NOT SEE IT UNTIL LATE SO LOWERING THE TEMPS THERE TO NEAR 40. MORE ADJUSTMENTS MAY NEED TO BE MADE AS THE SITUATION WITH THE SYSTEM ON SATURDAY RESOLVES ITSELF. EXTENDED (MONDAY THROUGH THURSDAY)...MODELS CONTINUE TO HAVE GOOD AGREEMENT ON THE OVERALL PATTERN NEXT WEEK...SHOWING A DEEP TROUGH FORMING OVER THE WESTERN U.S. AND RIDGING OVER THE EAST. THE DETAILS ARE MORE COMPLICATED. HIGH PRESSURE THAT IS OVER THE GREAT LAKES SUNDAY MOVES EAST ON MONDAY AS A SHRTWV RIDES NORTHEAST IN THE SOUTHWESTERLY FLOW ALOFT. THIS SHRTWV...AND ITS ASSOCIATED SURFACE LOW...MOVE TO NORTHERN ONTARIO BY TUESDAY MORNING. THE COLD FRONT WITH THE SURFACE LOW STALLS SOMEWHERE AROUND THE WESTERN U.P. INTO WEDNESDAY MORNING (ECMWF NEAR DLH AND 00Z GFS AROUND MARQUETTE). ANOTHER SHRTWV THEN EXITS THE WESTERN TROUGH WHICH THE MODELS HAVE SOME ISSUES WITH. THE 00Z...06Z AND 12Z GFS AND HALF OF THE 00Z GFS ENSEMBLES HAVE THE FLOW NOT AS AMPLIFIED...THEREFORE ALLOWING THIS SHRTWV TO SHOVE THE STALLED COLD FRONT SOUTH TO MILWAUKEE BY 06Z THU. THE OTHER HALF OF THE ENSEMBLES ALONG WITH THE ECMWF AND UKMET SUGGEST MORE AMPLIFIED FLOW AND THUS ALLOW THE SHRTWV TO MOVE MORE NORTHERLY AND MOVE THE FRONT NORTH. EVENTUALLY THE GFS RUNS DO BRING THE FRONT NORTH LATE THU DUE TO ANOTHER SHRTWV EJECTING OUT OF THE DEEPENING WESTERN TROUGH. GIVEN THE UNCERTAINTY...WILL FOLLOW HPC PROGS WHICH FOLLOWS THE GFS RUNS. EXPECT DRY WEATHER FOR MONDAY AND THEN A CHANCE OF SHOWERS AND THUNDERSTORMS LATER TUESDAY THROUGH WEDNESDAY WITH THE COLD FRONT. WILL DRY THINGS OUT WEDNESDAY NIGHT WITH THE FRONT FAR ENOUGH SOUTH...BUT THEN INTRODUCE ANOTHER CHANCE OF SHOWERS AND THUNDERSTORMS FOR THURSDAY AS THE FRONT HEADS NORTH. TEMPERATURES GENERALLY AT OR ABOVE NORMAL (SHOULD THE ECMWF/UKMET CAMP BE CORRECT THE WHOLE PERIOD WILL BE ABOVE NORMAL). SEVERE WEATHER IS NOT OUT OF THE QUESTION EITHER IF THE 06Z GFS IDEA IS CORRECT WITH A PATTERN LOOKING MORE LIKE JULY THAN SEPTEMBER. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ AJ mi