AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER COLORADO 300 PM MST THU MAR 16 2006 .SHORT TERM DISCUSSION...TWO ITEMS OF CONCERN TODAY. FIRST IS THE PRECIPITATION CHANCE IN THE HIGH COUNTRY. VERY LITTLE GOING ON UPSTREAM OF US AT THIS POINT IN TIME ALTHOUGH THE RUC QG ANALYSES HAVE BEEN SHOWING CONSISTENT...ALBEIT WEAK...ASCENT OVER THE GREAT BASIN FOR MOST OF THE DAY. UNFORTUNATELY THIS ASCENT IS LIFTING SOME PRETTY DRY AIR...AS HAS BEEN THE CASE MOST OF THIS WINTER...SO EXPECT ANY MOUNTAIN PRECIPITATION TO HOLD OFF UNTIL AFTER 12Z FRIDAY. ONCE ANYTHING THAT DOES GET GOING UP THERE STARTS IT SHOULD NOT AMOUNT TO VERY MUCH AS OROGRAPHIC ENHANCEMENT IS NOT TERRIBLY FAVORABLE WITH THE SOUTHWEST FLOW...LAPSE RATES ARE NOT TOO GOOD AND THE QG LIFT REMAINS RATHER MARGINAL THROUGH THE DAY. ALL OF THESE IDEAS ARE SUPPORTED BY THE LATEST LOCAL MM5 RUN SHOWING ONLY SCANT PRECIPITATION AMOUNTS IN THE MOUNTAINS. THE OTHER ITEM IS THE COLD AIR LURKING ABOUT TO OUR NORTHEAST AND HOW MUCH OF THAT WILL OOZE INTO THE CWA. MODELS SUGGEST THAT IT SHOULD MAKE IT INTO THE NORTHEAST PART OF THE CWA BUT ITS SHALLOWNESS WILL NOT BODE WELL FOR IT MAKING IT UP THE HILL INTO THE DENVER AREA. WITH THAT IN MIND HAVE LOWERED TEMPERATURES SOME NORTH AND EAST OF DENVER TOMORROW. .LONG TERM DISCUSSION...FOCUS CONTINUES TO BE ON EVOLUTION OF AN UPPER TROUGH OVER THE SOUTHWESTERN U.S. THROUGH THE WEEKEND. MODEL RUNS FROM 12Z CONTINUED THE PRIOR TREND OF AN ELONGATED...NEGATIVELY TILTED UPPER TROUGH STRETCHING FROM NEW MEXICO TO WASHINGTON BY SUNDAY EVENING. SURFACE PRESSURE PATTERNS CONTINUED WITH A SURFACE LOW OVER SERN CO/NERN NM AND A STRONG SURFACE HIGH OVER CANADA. THIS LOW LEVEL PATTERN WOULD ALLOW GULF MOISTURE TO ADVECT NORTHWARD OVER THE GREAT PLAINS AND INTO ERN CO. WITH THE DEPTH OF THE TROUGH AND THE AVAILABILITY OF MOISTURE THROUGH THE WEEKEND...IT IS BECOMING CLEAR THAT A PROLONGED PRECIPITATION EVENT WILL DEVELOP OVER THE MOUNTAINS AND SPREAD ONTO THE PLAINS AT SOME POINT. THE 18Z RUN OF THE NAM IS NOW SHOWING THE TROUGH TO HAVE LESS ELONGATION TO IT...WHICH WOULD ALLOW MORE CIRCULATION TO DEVELOP OVER EASTERN COLORADO ON SUNDAY AFTERNOON. IF THE MODELS CONTINUE THIS TREND THROUGH TOMORROW...HIGHLIGHTS FOR THE LATTER HALF OF THE WEEKEND MAY BECOME NECESSARY. FOR NOW...WILL JUST STICK WITH PROBABILITY OF PRECIPITATION VALUES IN THE CHANCE CATEGORY. BEFORE THE TROUGH ARRIVES...OR POSSIBLY CUTS OFF...SATURDAY SHOULD SEE INCREASING PRECIPITATION IN THE MOUNTAINS AS MOIST SOUTHWESTERLY FLOW ALOFT CONTINUES. ON THE PLAINS...TEMPERATURES WILL BE COOLER AS SHALLOW COLD AIR FROM THE NORTHERN PLAINS MOVES IN FROM THE NORTHEAST. LOW LEVEL TEMPERATURE FIELDS FROM THE NAM AND GFS DO NOT SHOW THE MAIN COLD AIR MOVING INTO THE REGION UNTIL SUNDAY...BUT MOS GUIDANCE VALUES SHOW THE INITIAL COOLING ARRIVING SATURDAY. IF THE COOLER AIR MOVES ONTO THE PLAINS SATURDAY AFTERNOON...THEN A CHANCE OF UPSLOPE PRECIPITATION WON'T BE TOO FAR BEHIND. SUNDAY AND SUNDAY NIGHT'S PRECIPITATION EVENT WILL BEGIN WINDING DOWN OVER OUR FORECAST AREA THROUGH MONDAY. WITH UPPER LEVEL RIDGING FORECAST TO DEVELOP OVER THE WESTERN U.S. ON MONDAY...DRIER WEATHER AND MODERATING TEMPERATURES ARE EXPECTED THROUGH THE FIRST HALF OF NEXT WEEK. && .BOU WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ET/KDRBY co AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE LOUISVILLE KY 905 PM EST THU MAR 16 2006 .UPDATE... ISLTD TO SCT SHRA HAVE DEVELOPED OVER CNTRL/NRN SECTIONS OF THE CWA WITHIN THE PAST HALF-HOUR...AS SFC LOW DROP SE TO NEAR BEDFORD INDIANA AS OF 01 UTC MSAS ANALYSIS. 3HR SFC PRES FALL PATTERN SUGGESTS LOW WILL TRACK ESE TOWARD CRW DURING THE REMAINDER OF THIS EVENING. WILL CONTINUE ONGOING FCST OF 20-40% COVERAGE OF SHRA THROUGH AT LEAST 06-08 UTC. EVEN WITH SHOWERS...SKIES ARE ACTUALLY PARTLY CLOUDY OVER MUCH OF THE CWA...GIVEN CELLULAR NATURE TO THE PCPN. THERE HAVE ACTUALLY BEEN A NUMBER OF MDT-SVR TURBULENCE REPORTS BELOW FL180 THIS EVENING OVER IN/IL/KY...OWING TO CONVECTIVE NATURE OF PCPN. SOME HIGHER REFLECTIVITIES SHOWING UP ON MOST RECENT SCANS...SO THUNDER NOT OUT OF THE QUESTION AND IF THAT HAPPENS...SMALL HAIL POSSIBLE GIVEN RELATIVELY LOW FREEZING LEVELS...7300FT PER 0145 UTC ACARS SOUNDING AT SDF. FOLLOWING LATEST RUC...FEEL THAT LOWER STRATUS IN THE COLD AIR WILL WORK INTO THE CWA AROUND OR AFTER 09 UTC. HAVE RAISED FCST MINS A COUPLE DEGREES BASED ON LATEST RUC/NAM DATA. UPDATED FCST OUT BY 915 PM. CS && PREV DISCUSSION... (ISSUED 315 PM EST EST THU MAR 16 2006) SHORT TERM (TONIGHT AND FRIDAY) SKIES CLEARED FOR A WHILE LATE THIS MORNING INTO EARLY AFTERNOON BUT SINCE 19Z CLOUDS HAVE INCREASED ACROSS SOUTHERN INDIANA AND NEARLY ALL OF CENTRAL KENTUCKY AS A WARM FRONT IS MOVING ACROSS THE AREA. WINDS HAVE BEEN SHIFTING TO THE SOUTHWEST WITH GUSTS TO 20 MPH OR SO. LOW PRESSURE...OVER CENTRAL ILLINOIS AT 19Z WILL CONTINUE MOVING TO THE SOUTHEAST. IF THE LOW CONTINUES ON ITS PRESENT TRACK IT WILL PASS VERY NEAR LOUISVILLE THEN JUST SOUTH OF LEXINGTON ON ITS WAY INTO SOUTHEAST KENTUCKY. SO FAR ANY PRECIPITATION THAT HAS BEEN ASSOCIATED WITH THE LOW HAS BEEN LIGHT. A FEW RETURNS HAVE SHOWN UP ON KLVX RADAR DURING THE PAST HOUR SO PRECIPITATION WITH THE WARM FRONT ACROSS THE EASTERN PART OF THE FORECAST AREA SEEMS REASONABLE...BUT WILL KEEP POPS IN THE CHANCE CATEGORY. PRECIPITATION TONIGHT IS THE BIG QUESTION. BOTH NAM AND GFS KEEP LOW NEAR OR TO OUR NORTH...BUT THE POPS DIFFER. GFS IS HIGHER... ESPECIALLY ACROSS THE NORTHERN PARTS OF THE STATE. WILL LEAN CLOSER TO THE LOWER NAM MOS FOR POPS AND WILL USE A BLEND ON TEMPERATURES. AFTER THE WARM FRONT MOVES THROUGH...THERE WILL BE A PERIOD OF PARTLY CLOUDY SKIES AND GUSTY SOUTHWEST WINDS. THEN OVERNIGHT THE COLD FRONT WILL PUSH THROUGH WITH LOWER CLOUDS OVERSPREADING THE FA. THESE CLOUDS WILL PERSIST ACROSS MUCH OF THE AREA INTO MIDDAY FRIDAY THEN CLOUDS WILL BEGIN TO DECREASE FROM THE WEST. HAVE RAISED TEMPERATURES A DEGREE OR TWO TONIGHT WITH SKIES STAYING MOSTLY CLOUDY. HIGH TEMPERATURES ON FRIDAY WILL BE SOME 20 DEGREES COOLER THAN TODAY. SCHOLZ LONG TERM (FRIDAY NIGHT THROUGH THURSDAY)... ONE FCST PROBLEM FOR THE LONG TERM CONTINUES TO BE THE AMOUNT OF COOLING BEHIND A SHORT WAVE EXITING THE REGION TONIGHT. HOWEVER..THE MAIN FORECAST PROBLEM IS THE PCPN POTENTIAL FROM A SHORT WAVE THAT MOVES FROM THE SOUTHERN ROCKIES ACROSS THE FA IN THE MONDAY AND TUESDAY TIME FRAME. THERE IS SOME POTENTIAL FOR SOME WET SNOW ON THE BACK SIDE OF THIS SYSTEM DURING TUESDAY. THE LATEST GFS 12Z MODEL THICKNESS VALUES ARE MORE INDICATIVE OF SOME WET SNOW POTENTIAL ACROSS THE NORTHERN PORTION OF OUR FA...BUT THIS SEEMS OVER DONE...SO WILL NOT INTRODUCE ANY MENTION OF SNOW IN THIS FORECAST. I PREFER TO WAIT UNTIL THE MODELS GET A LITTLE MORE CONSISTENT FROM RUN TO RUN. THERE IS STILL PLENTY OF TIME TO DEAL WITH THIS. THE GFS HAS BEEN TRENDING TOO COLD HERE. THE ECMWF IS A LITTLE SLOWER AND WARMER WITH THIS SYSTEM. SO ITS A MIXED BAG. SO WE WILL KEEP THE PREVIOUS FCST TRENDS WITH SOME TIMING ADJUSTMENTS FOR ONSET OF THE PCPN. WE WILL ALSO RAISE THE MIN TEMPS AND LOWER THE MAX TEMPS FOR A MORE RESTRICTED TEMPERATURE RANGE DURING THE MONDAY NIGHT AND TUESDAY PERIOD WHEN THE PCPN CHANCES ARE THE GREATEST. --21 && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1045 PM EST THU MAR 16 2006 .SHORT TERM /REST OF TONIGHT THROUGH FRIDAY/... NICE LITTLE THUNDERSTORM OBSERVED ON RADAR AROUND CINCY...ASSOCIATED WITH LOW PRESSURE JUST EAST OF LOUISVILLE AT 02Z. MODELS ARE IN AGREEMENT ON LOW PRESSURE MOVING SOUTH OF OUR CWA OVERNIGHT INTO EARLY FRIDAY...WITH A BAND OF PRECIP MOVING THROUGH. HOWEVER...THEY DISAGREE ON WHERE THIS BAND WILL SET UP. THE GFS/RUC WOULD ARGUE FURTHER NORTH BUT THE NAM LIKES THIS BAND TO SET UP FURTHER SOUTH AND IN FACT THE 18Z NAM FIZZLES OUT THE BAND SOONER THAN ITS 12Z. WE FAVOR THE GFS...AND THE 18Z SPREADS SOME DECENT QPF IN A NW TO SE BAND ACROSS A WIDER PORTION OF OUR CWA WHICH INCLUDES THE DC METRO AREA. RUNNING SNOW TOTALS ON THE 18Z GFS RUN ARE VERY INTERESTING...WITH 2-3 INCH TOTALS MAKING THEIR WAY INTO THE DISTRICT (KIND OF ALONG HIGHWAY 50). HOWEVER...BASED ON PROFILES...PRECIPITATION LIKELY STARTS OUT AS RAIN FOR A 1 TO 2 HOUR PERIOD BEFORE COOLING SUFFICIENTLY CAUSES PRECIPITATION TO FALL AS SNOW. IN ADDITION...THIS SYSTEM WILL NO DILLY DALLY ON ITS EASTWARD PROGRESS...SO THESE RUNNING TOTALS REFLECTED ON THE GFS APPEAR TOO LARGE. HOWEVER...MAKING ADJUSTMENTS TO RUNNING TOTALS...WE CAN SEE 1 TO 2 INCHES MAKING ITS WAY INTO FREDERICK AND LOUDOUN COUNTIES AND WE HAVE EXPANDED THE SNOW ADVISORY EAST INTO THESE COUNTIES. WE ALSO INCREASED SNOW TOTALS FROM LITTLE TO NO ACCUMULATION ACROSS THE REST OF THE DCA AND BALT METRO AREAS TO AROUND AN INCH OR AN INCH OR LESS. GIVEN WARM GROUND...THESE WOULD MAINLY BE ON GRASSY SURFACES. && .AVIATION... PRECIP EXPECTED TO BE -RA OR -RASN INITIALLY BEFORE SHIFTING OVER TO ALL SNOW. LATEST GUIDANCE SUGGESTS HEAVIER BAND COULD SET UP FURTHER NORTH AND AFFECT KIAD/KDCA. && .PREV DISCUSSION... /ISSUED 333 PM EST THU MAR 16 2006/ SHORT TERM /TONIGHT THROUGH FRIDAY/... WATER VAPOR LOOP SHOWS AN UPPER LOW ACROSS THE CANADIAN MARITIMES...WHILE A WAVE TRAVERSES SOUTHEAST ACROSS THE MIDWEST. ACARS 400-250MB WIND OBSERVATIONS REVEAL A 120-150KT JET STRETCHES FROM THE PLAINS EAST NORTHEAST THROUGH THE MID ATLANTIC REGION. 12Z SURFACE ANALYSIS PLACES A 1024MB ANTICYCLONE ACROSS THE SOUTHEAST CONUS. A COLD/STATIONARY BOUNDARY WAS DRAPED SOUTHWEST DOWN THE NEW ENGLAND COAST...THROUGH THE OHIO VALLEY TO A 1008MB CYCLONE ACROSS NORTHWEST MISSOURI. THE PRIMARY COLD FRONT EXTENDED SOUTHWEST FROM THE CYCLONE ACROSS CENTRAL TEXAS. A LEE TROUGH WAS NOTED ALONG THE MID ATLANTIC APPALACHIANS. NAM/GFS/WRF ALL INDICATE A 50-100 WIDE BAND OF PRECIPITATION DEVELOPS FROM THE OHIO VALLEY SOUTHEAST ACROSS THE MID ATLANTIC REGION LATE TONIGHT INTO FRIDAY MORNING...FORCED BY THE SHEARING MIDWEST WAVE WHICH IS INCREASING FRONTOGENESIS ACROSS THE AREA. THE MODELS DIFFER ON THE LOCATION OF THE BAND...GFS IS FARTHEST NORTH...AND THE WRF IS FURTHER SOUTH (MAINLY IN BLACKSBURGS CWA). DECIDED TO GO WITH THE NAM AS A COMPROMISE. A WEAK COLD FRONT SAGGING SOUTH FROM PENNSYLVANIA WILL PASS THROUGH MOST OF THE FORECAST AREA THROUGH THE NIGHT. IT IS LIKELY THAT THE PRECIPITATION BAND DEVELOPS JUST NORTH OF THE FINAL RESTING LOCATION OF THIS FRONT EARLY FRIDAY MORNING. THE BETTER RESOLUTION NAM (AND PERHAPS WRF) PROBABLY WILL DO A BETTER JOB AT LOCATING THE FRONT...AND HENCE THE BAND OF SNOW (FURTHER SOUTH THAN GFS). TODAY WAS QUITE WARM...WITH MARYLAND ROADWAY SENSORS INDICATING PAVEMENT TEMPERATURES OF 55-70 DEGREES. MODELS INDICATE QUITE A SHOT OF OMEGA THROUGH THE DENDRITIC LAYER WITHIN THIS BAND...WHICH SHOULD OVERCOME THE WARM SURFACES THROUGH A HIGH SNOW RATE. PRECIPITATION MAY BRIEFLY BEGIN AS RAIN BEFORE EVAPORATIVE COOLING QUICKLY PROMOTES SNOW. DUE TO THE UNCERTAINTY OF THE BAND LOCATION...DECIDED TO ISSUE A SNOW ADVISORY WEST OF THE BLUE RIDGE. EXPECTING A 50-100 MILE CORRIDOR OF THIS AREA TO SEE THE ADVERTISED SNOW ACCUMULATION. FURTHER EAST...TEMPERATURES WILL BE WARMER OVERNIGHT...LOWERING THE CONFIDENCE OF ACCUMULATING SNOW FURTHER SOUTHEAST (UNLESS THE BAND IS ABLE TO SET UP THERE). IMPROVING CONDITIONS EXPECTED BY LATE MORNING AS THE SHEARED WAVE PASSES TO THE SOUTHEAST OF THE FORECAST AREA. LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... THE FIRST PORTION OF THE EXTENDED FORECAST WILL BE FAIRLY QUIET. THE REMAINDER OF THE EXTENDED PERIOD WILL BE DOMINATED BY A COASTAL SYSTEM AND UNSETTLED WEATHER TO FOLLOW. AT THE BEGINNING OF THE PERIOD...UPPER LOW IS SITUATED OVER NEW ENGLAND WITH THE CWFA IN NORTHWEST FLOW ON THE BACKSIDE OF THE TROUGH...WITH SHORTWAVES MOVING THROUGH THE FLOW. THE SHORTWAVES SHOULD ONLY LEND TO SOME CLOUDINESS THROUGH THE WEEKEND. TEMPERATURES ARE EXPECTED TO REMAIN SLIGHTLY BELOW NORMAL THROUGH THE PERIOD. THE GFS IS PROGGING A COASTAL SYSTEM DURING FOR THE FIRST PART OF NEXT WEEK. THE EVENT LOOKS TO BRING ANOTHER ROUND SNOW IN THE NORTHERN HALF OF THE CWFA...WITH A RAIN/SNOW MIX IN THE SOUTHERN HALF. TOO FAR OUT TO GET SPECIFIC WITH THE DETAILS. GENERALLY FAIR WEATHER OUT FOR THE LAST PART OF THE WEEK...WITH SOME POTENTIAL FOR UPSLOPE PRECIP ALONG AND WEST OF THE ALLEGANY FRONT. AVIATION... MIDLEVEL CLOUDS THICKENING AND LOWERING LATE TONIGHT. 50-100 MILE BAND OF SNOW TO DEVELOP LATE TONIGHT ACROSS REGION. STILL A LARGE SPREAD IN LOCATION BETWEEN GFS-NAM-WRF. NAM WAS THE COMPROMISE...WHICH PUT THE HEAVIER SNOW/LOWER CIG AND VISBYS NEAR CHO. MARINE... WILL CONTINUE SMALL CRAFT ADVISORY UNTIL 5PM FOR 20KT WIND GUSTS. THESE SHOULD DIMINISH AS GRADIENT RELAXES WITH ARRIVAL OF COLD FRONT. WATER LEVELS ARE CURRENTLY NEARLY A FOOT BELOW PREDICTED VALUES. THE LUNAR CYCLE IS WANING FROM A FULL MOON. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...SNOW ADVISORY FOR MDZ002>004 FROM 3 AM FRIDAY TO 10 AM FRIDAY. VA...SNOW ADVISORY FOR VAZ021-025>031-042 FROM 3 AM FRIDAY TO 10 AM FRIDAY. WV...SNOW ADVISORY FOR WVZ048>055 FROM 3 AM FRIDAY TO 10 AM FRIDAY. MARINE...NONE. && $$ SHORT TERM/AVIATION...PELOQUIN PREV DISCUSSION...ROGOWSKI/LISTEMAA md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 320 PM EST THU MAR 16 2006 .SYNOPSIS... WATER VAPOR IMAGES SHOW A DIGGING TROUGH OFF THE W COAST...WHICH IS ALREADY STARTING TO INDUCE DOWNSTREAM RIDGING OVER THE INTERMOUNTAIN W. LOCALLY...A SHORTWAVE TROUGH OVER ERN IA IS HELPING TO INDUCE FGEN NEAR A WELL DEFINED SNOWBAND EXTENDING FROM ERN IA...THROUGH NRN IL...AND INTO NRN IN. IFR AND LIFR VSBYS IN SN WERE BEING REPORTED UNDER THIS BAND. .SHORT TERM (TONIGHT THROUGH SATURDAY NIGHT)... MAIN CONCERN IS WHAT TO DO WITH THE CURRENT SNOW ADVISORY. ALTHOUGH THERE IS GOOD SN FALLING AT THIS TIME UNDER THE BAND...WARM SURFACE TEMPERATURES AND PHONE REPORTS INDICATE THAT NOTHING HAS THE CHANCE TO STICK. FURTHERMORE...RUC PROGS SHOW BEST FGEN WILL PUSH E AND WEAKEN BY 00Z AS THE H8 LOW OPENS UP. SO...CURRENT THINKING IS THAT WE WILL DROP THE ADVISORY. OTHERWISE...SHORT RANGE MODELS ARE IN GOOD AGREEMENT WITH THE CWFA BEING BETWEEN SYSTEMS...NAMELY A DEEP APPROACHING TROUGH OVER THE WRN USA AND A BROAD STACKED LOW CENTERED OVER THE NEW BRUNSWICK AREA. THIS WILL KEEP A SHARP RIDGE JUST UPSTREAM AND DEEP SUBSIDENT NWLY FLOW OVER THE CWFA FOR MOST OF THE PERIOD. TONIGHT - WILL DROP THE ADVISORY AND GO CLOSER TO 1-3 INCH TOTALS. FRIDAY - HAVE LOWERED POPS TO SILENT AS LOW SFC-H8 DELTA T AND LOW MEAN RH VALUES WITH BROAD SUBSIDENCE KEEP LAKE EFFECT NEGLIGIBLE. SATURDAY/SATURDAY NIGHT - NO SIGNIFICANT CHANGES WERE MADE. .LONG TERM (SUNDAY THROUGH THURSDAY)... FOR THE EXTENDED PERIOD BLOCKING CONTINUES AT 500MB ACROSS THE NORTH PACIFIC. THIS HAS ALLOWED LOWERING OF HEIGHTS FROM THE ALEUTIANS EAST THROUGH WESTERN CANADA. THROUGH THE EXTENDED PERIOD HEIGHTS WILL BEGIN TO RELAX ACROSS NORTHERN PACIFIC...WITH THE ATMOSPHERIC BLOCK RETROGRADING WEST TOWARDS THE DATELINE. MODELS HAVE BEEN IN AGREEMENT THROUGH THE WEEKEND WITH KEEPING AN EASTERN PACIFIC LOW WEST OF THE CONUS...AND SLIDE SOUTH. EXTREME EASTERN QUEBEC MID LEVEL LOW WILL CONTINUE TO WEAKEN AND MOVE EAST. THE COMBINATION OF THE TWO MID LEVEL FEATURES WILL ALLOW BROAD RIDGING EXTENDING FROM NORTHERN PORTIONS OF ALBERTA...SASKATCHEWAN...AND MANITOBA EXTENDING SOUTH THROUGH CENTRAL CONUS. LATE WEEKEND PROPAGATION OF JET ALONG WEST COAST POINTS DUE S...WHICH WILL HELP DIG 500MB LOW OFFSHORE OF CA. SW CONUS JET INCREASES WITH DEVELOPMENT OF SOUTHERN STREAM LOW QUICKLY MOVING THROUGH CENTRAL PLAINS EARLY NEXT WEEK. EXPECT THE BULK OF MOISTURE AND DYNAMICS TO REMAIN SOUTH OF LWR MI...HOWEVER A SECOND AREA OF LOW PRESSURE CENTERED ACROSS WESTERN QUEBEC MAY FUNNEL MOISTURE AND CLOUDS INTO LWR MI. WEAK RETURN FLOW MOISTURE SHOULD AID IN ENHANCED PRECIP ACROSS OHIO RIVER VALLEY. 850MB TEMPS COOL TO -10 TO -13 DEG C THROUGH MID WEEK. WITH LGT NW FLOW...SCT FLURRIES OR SNOW SHOWERS MAY DEVELOP. EXPECT TEMPS TO REMAIN A FEW DEGREES BELOW NORM. && .GRR WATCHES/WARNINGS/ADVISORIES...SMALL CRAFT ADVISORY ALL NEARSHORE WATERS FROM 3 AM FRI THROUGH FRIDAY AFTERNOON. && $$ SHORT TERM: TJT LONG TERM: BEACHLER mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 300 PM EST THU MAR 16 2006 .DISCUSSION... 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW ZONAL FLOW ACRS THE SCNTRL CONUS TO THE S OF A VERY BLOCKED FLOW ACRS CANADA. DEEP NRLY STNRY VORTEX REMAINS OVER SCNTRL CAN...WITH OMEGA BLOCK UPR RDG OVER CNTRL CAN. SPRAWLING 1045MB SFC ARCTIC HI PRES BLDG INTO NRN MANITOBA UNDER THIS RIDGE. 12Z INL/YPL/YQD SDNGS SHOW DRY LLVLS... AND SFC DWPTS BLO 0F ACRS SCNTRL CAN/MUCH OF NW ONTARIO. 12Z PWATS AOB 0.10 INCH AT YQD/YPL/INL. SO DESPITE LGT NNE FLOW OF COLD AIR OVER LK SUP ATTM (UPSTREAM SFC TEMPS IN THE TEENS/H85 TEMPS ARND -13C)...NOTHING MORE THAN SOME PTCHY SC OBSVD OVER LK SUP. THERE IS A PAIR OF WEAK SHRTWVS ACRS NW ONTARIO AND SRN SASKATCHEWAN ON THE SRN FLANK OF THE RDG...BUT AIRMASS IS SO DRY MAINLY JUST HI CLD OBSVD. OTRW...FA IS ON NRN FRINGE OF HI CLD ASSOCIATED WITH RATHER POTENT LO PRES MOVING E THRU THE MID MS RIVER VALLEY. DRY NLY FLOW OUT OF RDG TO THE N WL KEEP THIS LO...ITS PCPN...AND EVEN MOST OF THE CLD COVER SAFELY TO THE S. MAIN FCST CONCERNS THE NEXT FEW DAYS ARE TEMPS/SMALL LES CHCS. LATEST MODEL GUIDANCE IN GOOD AGREEMENT SHOWING SFC-H85 RDG AXIS REMAINING NRLY STNRY JUST W OF THE FA TO THE S OF HI CENTER NEAR NRN MANITOBA AND W OF BLOCKING VORTEX IN SE CAN THRU SAT. WEAK SHRTWVS OVER NW ONTARIO/SRN SASKATCHEWAN FCST TO SHEAR OUT/WEAKEN IN THE DRY N FLOW E OF THE RDG AXIS/W OF THE BLOCKING LO TO THE E. GFS/NAM FCST SDNGS SHOW INVRN HGT REMAINING ARND H9 THRU THE TIME WITH LTL CHG IN INVRN BASE TEMP (-12C TO -14C)...SO DON'T THINK THERE WL BE ANYTHING MORE THAN FLURRIES. SINCE SUN IS GETTING HIER IN THE SKY AND INSOLATION BEGINNING TO DRIVE LK BREEZE CIRCULATION...SUSPECT LK CLD MIGHT BECOME MORE WDSPRD DURING THE NGTS AND THRU THE MRNG BEFORE BRKG UP IN THE AFTN WITH AIR TENDING TO RISE OVER LAND/SINK OVER WATER. WL PROBABLY MAINTAIN GOING FCST OF A BIT MORE CLD COVER/SML CHC POP ON FRI NGT/SAT OVER THE E AS LATEST NAM/UKMET HINT AT SOMEWHAT HIER H85 MSTR/LOWER H85 TEMP SWINGING BY WITH PASSAGE OF SHEARED SHRTWV NOW OVER NW ONTARIO AND MORE NW LLVL FLOW...BUT WL NOT BE TOO PESSIMISTIC CONSIDERING DRYNESS OF UPSTREAM AIRMASS. AS FOR TEMPS...WL GO AOB MOS GUIDANCE AT THE COLDER INTERIOR LOCATIONS AT NGT BUT THEN HAVE TEMPS RECOVERING AOA GUIDANCE WITH AT LEAST A GOOD DEAL OF SUNSHINE/JUST A FEW CU DURING THE AFTNS. THE MEDIUM/EXTENDED RANGE PROMISES TO BE A QUIET ONE WITH NEGATIVE NAO PATTERN PERSISTING...BLOCKING UPR RDG ACRS GREENLAND/NE CANADA LOCKING VORTEX IN PLACE ACRS SE CANADA. AT THE SFC...A SPRAWLING DRY AREA OF HI PRES WL REMAIN OVER CAN AND FORCE ANY LO PRES SYSTEMS MIGRATING E OUT OF WRN TROF TO STAY WELL S OF THE FA WITH RELATIVELY DRY NNE FLOW. ONLY PSBL FLYS IN THE OINTMENT WOULD BE SHRTWVS ROTATING ARND WRN FLANK OF STNRY VORTEX IN SE CAN AND PSBL WEAK LES. AT THIS POINT...TIMING DIFFERENCES ON THESE SHRTWS ABOUND. WL MAINTAIN PCLYD-MOCLDY SKIES/LO CHC POPS FOR THE LK SUP BORDER COUNTIES ON WED AND KEEP SN CHCS LINGERING THERE INTO THU. LATEST GFS RUNS SUG A SHRTWV PASSAGE ON TUE AS WELL...BUT WL HOLD OFF ON NO PCPN FCST GIVEN DRY LOOK OF ECMWF/UKMET/NCEP MANUAL GUIDANCE. OTRW... EXPECT A RELATIVELY WIDE DIURNAL RANGE IN TEMPS SUN-TUE WITH MAINLY CLR SKIES. NIGHTTIME LOWS OVER THE INTERIOR SHOULD FALL BLO MOS GUIDANCE...BUT DAYTIME TEMPS WL RECOVER NICELY UNDER INCRSGLY STRG LATE MARCH SUNSHINE. COORDINATED WITH GRB/DLH. && .MQT...NONE. && $$ KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1100 AM EST THU MAR 16 2006 .UPDATE... AT 15Z THE SURFACE LOW WAS OVER NE MO...AND THE BEST PRESSURE FALLS WERE LOCATED ALMOST DUE E OVER THE IL/IN BORDER. THIS IS ENCOURAGING FOR THE SNOW ADVY...AS THIS SUGGESTS A MORE EWD TRACK OF THE LOW COMPARED TO LATEST GFS/NAM/NAMX PROGS OF A SEWD TRACK. RADAR SUGGESTS SOME FGEN BANDING NEAR THE SRN WI STATE LINE...WITH SEVERAL METAR SITES REPORTING 1/2SM OR LESS. RUC H6 FGEN PROGS AGREE WELL WITH CURRENT RADAR DISPLAY...AND THIS AREA SHIFTS E TO FAR SRN LWR BY THIS AFTN. LOCAL SOUNDINGS QUITE DRY IN THE LOWER TROP THIS MORNING...BUT THIS COULD HELP WET BULB COOLING EFFECTS LATER THIS EVENING AND KEEP PCPN AS SN WHEN BETTER FGEN WORKS E INTO THE AREA. AFTER COORDINATION WITH IWX...HAVE LOWERED SN AMOUNTS SLIGHTLY...BUT WE ARE KEEPING THE ADVISORY GOING. TIMING LOOKS TO BE A LITTLE LATER...SO HAVE WORDED THIS IN THE UPDATED WSW. WILL UPDATE ZONES SHORTLY. MARINE - HAVE UPDATED THE WIND GRIDS TO MORE CLOSELY REFLECT SLIGHTLY STRONGER NAM WINDS. THIS PUSHES WAVES UP TO AROUND 4 FT BY 10Z FRI MORNING. AS THIS IS LATE IN THE PERIOD...WILL HOLD OFF ON A SCA FOR NOW. && .GRR WATCHES/WARNINGS/ADVISORIES...SNOW ADVISORY UNTIL 3 AM FRI FOR OTTAWA...ALLEGAN...BARRY...VAN BUREN...CALHOUN AND KALAMAZOO COUNTIES. && $$ TJT mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 1028 AM CST THU MAR 16 2006 .UPDATE... POTENT LITTLE VORT TREKKING ACROSS EASTERN IOWA ATTM. SNOW HAS TAPERED OFF FROM WEST CNTRL MN TO THE NORTHERN SUBURBS THIS MORNING. WILL LET WARNING EXPIRE AT NOON FOR WC MN TO THE TWIN CITIES AREA. SOME EVIDENCE OF MODEST BANDING IN PORTIONS OF SC MN INTO WISC AND DESPITE WEAKENING TREND IN MODELS...12Z NAM CROSS SECTIONS OF NEGATIVE EPV...OMEGA AND SPECIFIC HUMIDITY DO SUGGEST ENOUGH LIFT AND MOISTURE SUCH THAT ANOTHER 2-4 INCHES ARE POSSIBLE FROM AEL TO RGK AND EAU. IN FACT...BUFKIT SHOWS LIFT NOW IN THE SNOW GROWTH LAYER WITH ABOUT FOUR INCHES AFTER 12Z THIS MORNING. THUS WILL KEEP THE WARNING THROUGH THE AFTERNOON FOR SC MN TO EAU AREA. TDK. && .PREV DISCUSSION... /ISSUED 346 AM CST THU MAR 16 2006/ DISCUSSION...TODAY THROUGH SATURDAY NIGHT BAND OF SNOW ASSOCIATED WITH MID LEVEL FRONTOGENESIS...AND NEAR NORTH EDGE OF MAX 850 MB THETA E ADVECTION HAS SHIFTED EAST SOMEWHAT INTO WEST CENTRAL WISCONSIN...AND ALSO SAGGED SLIGHTLY FARTHER SOUTH SINCE 06Z. LAPS STORM TOTAL SNOW SHOWING 3 TO 4 INCHES FROM THIS BAND...AND SEEMS TO BE CLOSE BASED ON REPORTS WE WERE RECEIVING AT AROUND MIDNIGHT. 06Z NAM AND RUC SHOWING THAT THIS FORCING REMAINS CLOSE TO THE SAME AREA FOR A COUPLE HOURS THIS MORNING AND THEN SHIFTS SOUTH DURING MID MORNING AND WEAKENS SLIGHTLY. HOWEVER..VORT MAY OVER NE NEB AREA WILL ENHANCE FORCING OVER SOUTH CENTRAL MN THIS MORNING...AND THIS LINGERS INTO AFTERNOON. WINDS SHOULD KICK UP MORE OVER SOUTHERN MN AS SURFACE LOW PASSES ACROSS SOUTHERN IOWA. WILL KEEP THE WARNING GOING WITH SAME GENERAL TIME FRAME TODAY..BUT EXTEND INTO AFTERNOON ACROSS FAR SOUTHERN MN. SNOW AMOUNTS SHOULD WORK OUT OK. AREAS OVER SOUTH CENTRAL MN HAVE NOT RECEIVED MUCH SNOW YET BUT THIS SHOULD PICK UP THIS MORNING. WILL NEED TO WATCH AREAS AROUND MSP AREA INTO WEST CENTRAL WI THOUGH IF ANOTHER BAND DEVELOPS. A BIT OF A SUSPECT AREA OVER WEST CENTRAL MN IN TERMS OF REACHING WARNING SNOW AMOUNTS...BUT FAIRLY CLOSE TO SECONDARY FORCING MECHANISMS MENTIONED ABOVE. HIGH PRESSURE BUILDING IN LATER TONIGHT SHOULD BLOW CLEAR OUT THE CLOUDS IN MANY AREAS. DRIER AIR FRIDAY INTO SATURDAY...COMBINED WITH NEW SNOW SHOULD HELP TO DROP MID TEMPS BELOW GUIDANCE. LONGER TERM...SUNDAY THROUGH THURSDAY LATEST GFS...00Z VERSION...CONTINUES PREVIOUS TREND OF A VERY BLOCKY PATTERN WITH THE STORM TRACK ACROSS THE SOUTHERN UNITED STATES...AND A PERSISTENT SFC HIGH PRESSURE RIDGE POKING DOWN INTO MN FROM CANADA. TRIMMED BACK THE PRECIPITATION CHANCES TO JUST WESTERN AND SOUTHERN AREAS MONDAY NIGHT AND TUESDAY...AND THAT MAY STILL BE TOO MUCH. 00Z MEX TEMPERATURES DEPICT BELOW NORMAL VALUES...AND GIVEN THE SURFACE AND UPPER PATTERN FROM THE LAST 3 RUNS OF THE GFS THIS LOOKS QUITE REASONABLE. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WINTER STORM WARNING UNTIL NOON CST TODAY FOR ANOKA-BROWN-CARVER- CHIPPEWA-DAKOTA-HENNEPIN-KANDIYOHI-LAC QUI PARLE-LE SUEUR- MCLEOD-MEEKER-NICOLLET-RAMSEY-REDWOOD-RENVILLE-SCOTT-SIBLEY- SWIFT-WASHINGTON-WRIGHT-YELLOW MEDICINE COUNTIES. WINTER STORM WARNING UNTIL 6 PM CST THIS AFTERNOON FOR BLUE EARTH-FARIBAULT-FREEBORN-GOODHUE-MARTIN-RICE-STEELE-WASECA- WATONWAN COUNTIES. WI...WINTER STORM WARNING UNTIL 6 PM CST THIS AFTERNOON FOR CHIPPEWA- DUNN-EAU CLAIRE-PEPIN-PIERCE-ST. CROIX COUNTIES. && $$ JPR/MTF/RJN mn AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE JACKSON MS 1040 AM CST THU MAR 16 2006 .DISCUSSION... MOIST LOW LEVEL AXIS EXTENDING FROM SOUTHWEST TO NORTHEAST ACROSS THE REGION IS STARTING TO BE AFFECTED BY THE RIGHT ENTRANCE REGION OF A UPPER JET STREAK PIVOTING INTO THE SOUTHEAST CONUS. THIS BIT OF ENHANCED ATMOSPHERIC LIFT SHOULD BE ENOUGH TO GET AT LEAST SOME ISOLATED ELEVATED THUNDERSTORMS GOING OVER ALL BUT THE FAR NORTHWEST SECTIONS OF THE ARKLAMISS WITH AT LEAST SPOTTY SHOWERS AFFECTING MOST SPOTS BEFORE THE AFTERNOON IS OUT. HEAVY RAIN IS NOT ANTICIPATED AND THE RISK OF INTENSE THUNDERSTORMS APPEARS PRETTY LOW...MAINLY DUE TO THE ELEVATED NATURE OF CONVECTION AND VERTICAL TOTALS HOLDING LESS THAN 26. STILL COULD BE SOME SMALL HAIL FALLING FROM THE STRONGEST CORES...ESPECIALLY SOUTH OF I-20 IN NORTHEAST LA AND SOUTHWEST MS (WHERE BRIEF GUSTY WINDS WITH ANY STORMS WOULD ALSO NOT BE INCONCEIVABLE). THE FORECAST WAS UPDATED TO ADJUST TEMPERATURES A LITTLE (MAINLY A TOUCH DOWNWARD) WITH HIGHS EXPECTED TO HOLD IN THE 60S IN THE REGION WITH CLOUDS AND INTERMITTENT PRECIP. POPS WERE ALSO BROUGHT UP TO CATEGORICAL (80) IN PORTIONS OF CENTRAL MS AS RADAR TRENDS AND THE LATEST MODEL DATA SUGGEST VERY GOOD CHANCE OF AT LEAST LIGHT PRECIP AMOUNTS BY 00Z IN THESE AREAS. /BB/ && .PREVIOUS DISCUSSION... SHORT TERM(TODAY THROUGH FRIDAY)...WATER VAPOR IMAGERY/RUC ANALYSIS SHOWS A FAIRLY POTENT SHORTWAVE OVER THE CENTRAL PLAINS THAT IS SUPPORTING A SURFACE LOW OVER NORTHEAST KANSAS THAT WILL TRACK EAST AND DRAG A COLD FRONT ACROSS OUR AREA TONIGHT. AHEAD OF THE APPROACHING COLD FRONT MOISTURE WILL INCREASE TODAY. LOCAL WIND PROFILERS ACROSS EAST TEXAS...LOUISIANA AND MISSISSIPPI SHOW THE 80H FLOW HAS BECOME SOUTHWESTERLY AND INCREASED TO 30-40KTS. THIS HAS LED TO AN INCREASED MID LEVEL DECK ACROSS OUR CWA THIS MORNING INCLUDING A FEW RETURNS ON LOCAL RADARS IN THE SW THAT ARE LIKELY NOT REACHING THE GROUNDS. OUR SFC DEW POINTS HAVE BEEN SLOW TO INCREASE WITH SITES NORTH OF HIGHWAY 84 STILL IN THE MID 30S. HAVE BACKED OFF ANY POPS IN THE CWA UNTIL AFTER 6 AM. LIGHT RAIN WILL GRADUALLY DEVELOP FROM THE SOUTHWEST THIS MORNING. INSTABILITY LOOKS TO REMAIN LIMITED THIS MORNING WITH THE EXCEPTION OF SOME FAVORABLE MID LEVEL LAPSE RATES AND A FEW ISOLATED THUNDERSTORMS CAN'T BE RULED OUT IN OUR SOUTHWEST COUNTIES AND PARISHES BEFORE NOON. THE COLD FRONT IS EXPECTED TO BE IN OUR SOUTHEAST ARKANSAS COUNTIES BY 6 PM THIS EVENING. AN NARROW POOL OF DEEP MOISTURE IS EXPECTED JUST AHEAD OF THE COLD FRONT LATE THIS AFTERNOON...AS THE RIGHT ENTRANCE REGION OF A 110KT JET STREAK MOVES OVER OUR SOUTHERN COUNTIES AND PARISHES. THIS IS EXPECTED TO LEAD TO A BRIEF TIME PERIOD LATE THIS AFTERNOON INTO EARLY EVENING WHERE A FEW THUNDERSTORMS MAY BECOME STRONG ACROSS OUR SOUTHERN LOUISIANA PARISHES AND SOUTHWEST MISSISSIPPI COUNTIES. OTHERWISE...LIGHT RAIN WITH A FEW ISOLATED THUNDERSTORMS IS EXPECTED BEFORE THE COLD FRONT MOVES THROUGH. THE COLD FRONT SHOULD BE NEAR JACKSON AT MIDNIGHT AND SOUTH OF HATTIESBURG BY THE START OF THE DAY FRIDAY. THE BULK OF THE RAIN WILL FALL SOUTH OF I-20 TODAY AND HAVE GONE ABOVE GUIDANCE THERE. FRIDAY WILL BE DRY AS SHORTWAVE RIDGING BEGINS EDGING INTO OUR REGION WHILE SURFACE HIGH PRESSURE CENTERED OVER CANADA NOSES SOUTH ACROSS OUR REGION. TEMPERATURES WILL BE BELOW NORMAL FRIDAY BUT RATHER MILD WITH HIGHS IN THE 60S. /22/ COLD...WET WEEKEND IN STORE FOR THE CWA. ISENTROPIC LIFT TAKES OVER SAT MORNING AND LAST THROUGH MON. WE WILL NEED TO MOISTEN UP THE COLUMN SOME FIRST AND THAT WILL TAKE ALL DAY FRIDAY AND INTO SATURDAY SO NOT EXPECTING TO SEE MUCH IN THE WAY OF PRECIP UNTIL LATE SAT MORNING OR EVEN AFTER MIDDAY BUT ONCE IT STARTS IT COULD BE A LONG TIME UNTIL THE RAIN COMPLETELY ENDS. IT WILL START OF AS SHRA AND LAST LIKE THAT THROUGH MOST OF THE DAY SUN BUT BY SUN AFTERNOON THERE MAY BE SOME SCT EMBEDDED TSRA AS SOME ELEVATED INSTABILITY MOVES INTO THE AREA. THIS MAY ALL CHANGE MON AS TSRA WILL BE MORE WIDESPREAD AND THE RAIN MAY GETS HEAVIER AND STARTS TO ACCUMULATE POSSIBLY LEADING TO FLOODING ISSUES ESPECIALLY MONDAY AS SEVERE STORMS BECOME POSSIBLE. GFS CONTINUES TO COME MORE INLINE WITH THE EURO ON THE TIMING OF MONDAY'S SYSTEM. STILL A VERY IMPRESSIVE RAIN MAKER WITH THE POSSIBILITY OF SEVERE WEATHER. H5 LOW DIGS INTO THE STHRN PLAINS AND GOES NEGATIVELY TILTED MON WHILE THE SFC LOW TRACKS FROM TX THROUGH AR AND INTO TN/KY. GFS STILL SHOWING LL FLOW OF 45-55KTS BRINING IN H85 THETA E AIR OF 330K+ (UP TO 334K). VERY GOOD ELEVATED INSTABILITY WITH SHOWALTERS OF -3. WIND FIELD IS IMPRESSIVE AND FAVORABLE THROUGH THE ATMOSPHERE. THERE APPEARS TO BE A WEAK COUPLED JET FEATURE OVER ESTRN MS BY 00Z TUE WITH A 120KT+ JET CORE MOVING THROUGH NRTHN LA AND STHRN AR. 60 KT H5 FLOW INCREASING TO AS HIGH AS 100 KTS PUSHING INTO THE CWA LATE MON. 65 TO 80 KTS H7 BRINGING IN ANOTHER STRONG DRY PUNCH AND MENTIONED EARLIER A LL JET OF 45 TO 55 KTS SETTING UP OVER THE MS/AL BORDER. TRACK AND PLACEMENT OF H5 LOW AND SFC LOW HAVE BEEN FAVORABLE FOR SEVERE WEATHER IN THE PAST. DEEP MOISTURE IS IMPRESSIVE WITH PWS POSSIBLY APPROACHING 2" MON. THE PROBLEM MAY BE OVERALL INSTABILITY AND DEWPOINTS ONCE AGAIN. GFS DOES SHOW LOWER 60 DEWPOINTS AND MAYBE MID 60S DEWPOINTS PUSHING INTO THE AREA. ALSO WITH RAIN GOING ON THROUGH THE WEEKEND AND INTO MON THERE WILL BE CONSIDERABLE CLOUD COVER OVER THE AREA AND THIS WILL KEEP THE AREA FROM HEATING UP DURING THE DAY HINDERING DESTABILIZATION. I WILL CONTINUE TO MENTION IN THE HWO THE THREAT OF BOTH HEAVY RAIN AND STRONG TO SEVERE STORMS BUT THE MAIN THREAT LOOKS TO BE VERY HEAVY RAIN AS OF RIGHT NOW. AFTER THIS SYSTEM MOVES THROUGH LATE MON EARLY TUE...EXPECT DRIER AND MUCH COOLER CONDITIONS OVER THE AREA. SPEAKING OF TEMPS I AM VERY CONFUSED WITH THE GUIDANCE TEMPS. RIGHT NOW THE MEX GUIDANCE SEEMS TO WARM COMPARED TO THE LL TEMPS...ESPECIALLY TUE. LOOKING AT CLIMATE STATISTICS FOR OUR AREA...IN MID MARCH WITH H85 AND H925 TEMPS OF LESS THAN 2C(GFS SHOWING H85 TEMPS DROPPING THROUGHOUT THE DAY TO AS LOW AS -3C WHILE H925 TEMPS DROP TO -3/-4C) WE HAVE A VERY HARD TIME GETTING ABV THE UPPER 50S. THE BIGGER PROBLEM IS THAT THESE LL TEMPS ARE A GOOD BIT LOWER THAN 2C AND THIS MAKES IT HARD FOR US TO GET TO THE LOWER AND MID 50S. I HAVE A HARD TIME GOING 10 DEGREES OR MORE AWAY FROM GUIDANCE BUT I AM GOING TO GO A GOOD BIT COOLER ATLEAST 5 DEGREES EVERYWHERE AND A FEW MORE DEGREES IN SOME LOCATIONS. WILL WAIT TO SEE WHAT THE ENSEMBLE GUIDANCE HAS BEFORE MAKING FINAL ADJUSTMENTS. EITHER WAY IT LOOKS LIKE HIGHS WILL ACTUALLY OCCUR FAIRLY EARLY IN THE DAY WITH TEMPS COOLING THROUGH THE AFTERNOON. TEMPS REMAIN COOL THROUGH THE WEEK BUT DO START TO MODERATE A LITTLE BY WEEKS END. ALSO WE REMAIN DRY UNTIL POSSIBLY FRI BUT THE 3 DAYS OF DRY WEATHER MAY BE WELCOME FOR THE AREA TO DRY FROM THIS WEEKENDS DELUGE. /CAB/ && .AVIATION...VFR CONDITIONS WITH CEILINGS REMAINING ABOVE 3000FT ARE EXPECTED TO CONTINUE THROUGH 18Z OVER MOST OF THE AREA. AS RAIN AND A FEW THUNDERSTORMS INCREASE THIS AFTERNOON FROM THE SOUTHWEST BRIEF PERIODS OF MVFR CONDITIONS ARE EXPECTED. THUNDERSTORMS COVERAGE WILL BE GREATEST SOUTH INTERSTATE 20 TODAY. WIDESPREAD MVFR CONDITIONS WITH CEILINGS BETWEEN 2-3KFT ARE EXPECTED AFTER 00Z FRI AS THE COLD FRONT MOVES ACROSS THE AREA. /22/ && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ 50 ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC 832 PM EST THU MAR 16 2006 .SHORT TERM /TONIGHT/...MAIN CONCERN TONIGHT IS CLOUD COVER. TIME AND CROSS SECTIONS FROM THE RUC AND GFS40 HAVE BEEN CONSISTENT IN BRINGING IN MOISTURE BETWEEN H8 AND H5 TOWARD MORNING. WILL TWEAK SKY COVER GRIDS AND INCREASE CLOUDS AFTER 08Z OR SO. WITH CLEAR SKIES CURRENTLY AND TEMPS ALREADY DOWN NEAR FCST MINS...WILL DROP MINS A COUPLE OF MORE DEGREES AS WELL. OTHERWISE...FCST DATABASE IN GOOD SHAPE THIS EVENING. && .AVIATION...GENERALLY VFR CONDITIONS AS CLEAR SKIES CURRENTLY GIVE WAY TO BROKEN DECK OF CLOUDS IN THE VICINITY OF 5K FT TOWARD MORNING. && .MARINE...PLACEMENT OF WEAK HIGH PRES OFF THE NRN OUTER BANKS AND WEAK LOW OFF OCRACOKE CREATING SE WINDS N OF OREGON INLET WITH SW ELSEWHERE. MAY FINE TUNE WIND DIRECTIONS A BIT...BUT OVERALL FCST IN GOOD SHAPE. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY FOR AMZ150-152 FROM NOON FRIDAY TO 7 AM SATURDAY. ...SMALL CRAFT ADVISORY FOR AMZ154-156 FROM 2 PM FRIDAY TO 1 AM SATURDAY. && $$ COLLINS nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BISMARCK ND 930 PM CST THU MAR 16 2006 .UPDATE...MINOR UPDATE TONIGHT...MAINLY DEALING WITH CLOUD COVER. SATELLITE IMAGERY INDICATES CLEAR SKIES ACROSS THE CWA EXCEPT FOR THE FAR SOUTHWEST WHERE MVFR STRATUS REMAINS. RUC AND NAM BOTH INCREASE THE 925 MB RH IN THE WEST THROUGH THE NIGHT SO WILL ADJUST CLOUD COVER TO MOSTLY CLEAR FOR ALL BUT THE SOUTHWEST THIS EVENING THEN INCREASE THE STRATUS OVER THE WEST AFTER MIDNIGHT. WILL KEEP MENTION OF PATCHY FOG BUT WILL CUT BACK ON ITS EASTERN EXTENT TO WEST OF THE MISSOURI RIVER. OTHERWISE PREVIOUS FORECAST IS IN GOOD SHAPE. && .PREVIOUS DISCUSSION... .SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT... MAIN FORECAST HIGHLIGHT/CONCERN WILL BE PATCHY FOG ALONG WITH LOW CIGS TONIGHT WEST AND SOUTH...THEN A GOOD CHANCE OF ACCUMULATING SNOW WEST AND CENTRAL OVER THE WEEKEND. CURRENTLY...MID TO UPPER LEVEL CLOUDS THINNING AND MOVING EAST PRODUCING PARTLY TO MOSTLY SUNNY SKIES ACROSS THE MAJORITY OF THE FORECAST AREA THIS AFTERNOON. SOME CONVECTIVE LOW CUMULUS CLOUDS WERE CREATING MOSTLY CLOUDY CONDITIONS SOUTHWEST. MODEL GUIDANCE AND SYNOPTIC PATTERN IN ADDITION TO SNOWMELT TODAY ALL SUGGEST LOW LEVEL CLOUDS DEVELOPING LATER THIS EVENING ALONG WITH SOME PATCHY FOG WEST AND SOUTH. HAVE THUS INCREASED SKY COVER AND INTRODUCED PATCHY FOG FOR AFTER MIDNIGHT AND BEFORE 15Z TOMORROW MORNING. EVENING SHIFT CAN RE-EVALUATE SITUATION LATER TONIGHT. WEAK UPPER LEVEL RIDGE BUILDS INTO THE NORTHERN PLAINS FOR FRIDAY...WITH SURFACE LOW PRESSURE WEST AND HIGH PRESSURE EAST. MAX TEMPERATURES WILL REMAIN SLIGHTLY BELOW SEASONAL NORMS DURING THE AFTERNOON AS SOUTHEASTERLY WINDS DEVELOP IN RESPONSE TO THE SURFACE PATTERN...AND INCREASE THROUGHOUT THE DAY WEST TO EAST. INCREASING CLOUDS ALSO ARE EXPECTED SOUTH TO NORTH THROUGH THE AFTERNOON AND EVENING AS MOISTURE IS ADVECTED INTO THE REGION. UPPER RIDGE SLIDES EAST FRIDAY EVENING WITH SOUTHWEST FLOW INITIATING ALOFT. SURFACE PATTERN REMAINS THE SAME WITH LOW PRESSURE WEST AND HIGH PRESSURE EAST...WITH THE GRADIENT SLOWLY INTENSIFYING OVER THE NEXT DAY OR SO. DECENT ISENTROPIC LIFT SETS UP FRIDAY NIGHT AND SATURDAY WITH THE MOISTURE ADVECTION AND STRONG LOW-LEVEL SOUTHEASTERLY FLOW. BY LATER FRIDAY NIGHT SNOW IS EXPECTED TO DEVELOP SOUTHWEST ONCE THE ATMOSPHERE SATURATES...THEN EXPAND NORTHWARD SATURDAY MORNING...COVERING MUCH OF THE WEST AND CENTRAL BY SATURDAY AFTERNOON. THIS PATTERN REMAINS OVER THE REGION THROUGH THE WEEKEND WITH SNOW LIKELY WEST AND A GOOD CHANCE OF SNOW CENTRAL. DRY HIGH PRESSURE EAST WILL MINIMIZE SNOW POTENTIAL OVER THE EASTERN FORECAST AREA. SOUTHEAST WINDS WILL ALSO BECOME WINDY SATURDAY AFTERNOON OVER THE ENTIRE CWA WITH NEAR ADVISORY VALUES PROBABLE. AT THIS POINT TOTAL SNOWFALL ACCUMULATIONS LOOK TO BE IN THE 1 TO 4 INCH RANGE...WITH THE HIGHEST NUMBERS OVER THE WEST. WITH THE SNOW AND WIND...WINTER HEADLINES COULD BE ISSUED AS EARLY AS LATE TONIGHT OR TOMORROW. HIGH PRESSURE PUSHES SOUTH AND WEST SUNDAY AFTERNOON/NIGHT...ENDING THE THREAT OF SNOW EAST TO WEST. .LONG TERM...MONDAY THROUGH THURSDAY NIGHT... THE LONG TERM IS DOMINATED BY A WEAK UPPER LEVEL RIDGE WEST OF THE STATE BETWEEN TWO LARGE LOW PRESSURE SYSTEMS...ONE EXITING OUR REGION OVER THE EASTERN CONUS AND CANADA AND THE OTHER OVER THE WEST COAST. KEPT A SLIGHT CHANCE OF SNOW IN WESTERN COUNTIES MONDAY AND MONDAY NIGHT...BUT THE SURFACE ARCTIC HIGH FROM CENTRAL CANADA NOSES SOUTHWARD INTO THE STATE KEEPING THE FORECAST AREA DRY AND COOLER THAN AVERAGE. BY THURSDAY THE GFS MODEL SHOWS A WEAK SHORTWAVE SYSTEM MOVING SOUTH OF THE REGION...BUT THE TWO MAIN UPPER LEVEL LOW PRESSURE SYSTEMS REMAIN ON EACH COAST OF NORTH AMERICA. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. $$ TWH/NH/JV nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 756 PM EST THU MAR 16 2006 .SHORT TERM (REST OF TONIGHT)... RAIN WAS SPREADING ACROSS THE AREA THIS EVENING...WITH ISOLATED THUNDER MOVING INTO EAST CENTRAL INDIANA. HAVE UPDATED FOR THIS IN THE WEST CENTRAL OHIO AND DAYTON ZONE GROUPS. NOT MANY CHANGES TO THE FCST...WILL LIKELY UPDATE AGAIN IN THE NEXT FEW HOURS AS SFC LOW MOVES CLOSER AND PCPN COVERAGE CHANGES. && .PREVIOUS DISCUSSION... (ISSUED 653 PM EST THU MAR 16 2006) AVIATION (00Z-24Z)... RAIN WILL MOVE ACROSS THE TAF SITES OVER THE NEXT FEW HOURS BUT CONDITIONS WILL REMAIN VFR THROUGH AT LEAST MID EVENING. KDAY WILL SEE P6SM SNOW FOR THE NEXT HOUR. A CLUSTER OF CONVECTION CLOSE TO THE SFC LOW IN SW INDIANA DOES CONTAIN SOME LIGHTNING...AND WILL MONITOR THIS TO SEE IF IT HOLDS TOGETHER AS IT PROGRESSES EASTWARD. AS LOW PRESSURE MOVES SE OF THE TERMINALS...CEILINGS WILL BECOME MVFR AS WINDS SHIFT NE AROUND 12 KTS. COLDER AIR BEHIND THE LOW WILL CAUSE A CHANGE OVER TO SNOW 06Z TO 10Z. CIGS WILL BECOME VFR 12Z-14Z...LIKELY SCATTERING OUT 16Z TO 19Z. PREVIOUS DISCUSSION... (ISSUED 245 PM EST THU MAR 16 2006) SHORT TERM (TONIGHT THROUGH SATURDAY NIGHT)... DECENT RETURNS SHOWING UP ON RADAR ACROSS NORTHERN OHIO BUT WITH DRY AIRMASS IN PLACE...IT APPEARS THAT THIS PCPN IS NOT REACHING THE GROUND (NOT SURE IF THE .12 REPORTED ON THE AOH OB THIS PAST HOUR WAS REAL). 12Z MODELS HAVE TRENDED SLIGHTLY FARTHER SOUTH WITH THE TRACK OF THE LOW OVERNIGHT TONIGHT...SPREADING PCPN DOWN ACROSS AREA THROUGH THIS EVENING. HOWEVER...AM CONCERNED ABOUT LARGE DRY SLOT ACROSS SOUTHERN ILLINOIS AND LATEST RUC SEEMS TO BE PICKING UP ON THIS...KEEPING MUCH OF SOUTHWEST FA MAINLY DRY TONIGHT. ISENTROPIC LIFT IS FORECAST TO INCREASE ON THE 290K-295 K SURFACES BETWEEN NOW AND 03Z AS SURFACE LOW MOVES FROM CENTRAL ILLINOIS INTO SOUTHERN INDIANA. AS A RESULT...EXPECT TO SEE PCPN BEGIN TO FILL IN A LITTLE FARTHER SOUTH THAN WHERE THINGS ARE CURRENTLY SHOWING UP ON RADAR. WITH THIS IN MIND...WILL STILL ALLOW FOR PCPN TO DEVELOP DOWN INTO FA THROUGH THIS EVENING...BUT WE COULD END UP WITH A FAIRLY SHARP SOUTHERN EDGE. WILL THEREFORE...ONLY GO WITH CHANCE POPS ACROSS THE SOUTHWEST. MODELS FAIRLY CONSISTENT SHOWING BOUNDARY LAYER COOLING OFF FROM NORTH TO SOUTH ACROSS THE AREA OVERNIGHT. BASED ON BLEND OF FORECAST SOUNDINGS FROM THE GFS AND NAM...EXPECT PCPN TO MIX WITH AND THEN CHANGE OVER TO SNOW ACROSS THE FAR NORTH LATE THIS EVENING AND THEN ACROSS CENTRAL PORTIONS OF FA AFTER MIDNIGHT. ACROSS THE FAR SOUTH...ANY CHANGEOVER WOULD BE LATE TONIGHT OR FRIDAY MORNING. SNOWFALL ACCUMULATIONS ARE PROBLEMATIC AS DRY AIR IN PLACE AND RELATIVELY WARM GROUND TEMPERATURES WILL LIKELY CUT BACK ON ANY ACCUMULATIONS. HOWEVER...THIS WILL BE COUNTERED BY THE FACT THAT THE SNOW WILL BE FALLING DURING THE NIGHTTIME PERIOD AND POSSIBILITY FOR SOME CONVECTIVE ENHANCEMENT. ACROSS THE FAR NORTH...WHERE CHANGEOVER SHOULD OCCUR THE EARLIEST...WILL GO WITH 1 TO 2 INCHES WITH UP TO AN INCH DOWN TO ABOUT I-70. FARTHER TO THE SOUTH...CHANGE OVER SHOULD BE LATE ENOUGH TO LIMIT ANY ACCUMULATIONS. WILL HANG ON TO SOME LOWER CLOUDS THROUGH THE MORNING ON FRIDAY WITH LINGERING LOWER LEVEL MOISTURE AND CAA. WILL ALSO UNDERCUT GUIDANCE TEMPS A FEW DEGREES FOR HIGHS FRIDAY. OTHERWISE...HIGH PRESSURE THEN BUILDS IN THROUGH THE REMAINDER OF THE SHORT TERM FOR QUIET WEATHER INTO THE WEEKEND. LONG TERM (SUNDAY THROUGH THURSDAY)... MODELS HAVE TRENDED STRONGER AND SLOWER WITH THE STORM SYSTEM EARLY NEXT WEEK. THIS SUPPORTS YESTERDAYS 12Z RUN WHICH WAS SLOWER WITH THE ONSET OF PCPN. THEREFORE DELAYED THE ONSET OF PCPN UNTIL MONDAY NIGHT. GFS HAS BEEN TRENDING FARTHER SOUTH WITH THE LOW. 06Z RUN HAS THE LOW IN CNTRL KY AT 12Z TUE...12Z GFS NOW HAS IT IN ERN TN. WENT A BLEND OF 06Z/12Z GFS RUNS...SO WAS COOLER THAN THE 00Z MEX FOR HIGHS TUE. THE BLEND OF THE THICKNESSES PUTS THE RAIN/SNOW LINE AROUND THE OHIO RIVER FOR TUE...BUT THEREFORE SHOULD BE A CHANGE OVER TO ALL SNOW ON THE BACKEDGE. LOW PULLS OF THE EAST COAST TUESDAY NIGHT. WITH COLD NW FLOW...MODELS ARE SUGGESTING THAT THERE MIGHT BE SOME LAKE EFFECT SHOWERS WED AND THU. OTHER THAN BEING COOLER WITH TUE MAXS...WENT CLOSE TO MEX NUMBERS. SITES && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SHORT TERM... oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 653 PM EST THU MAR 16 2006 .AVIATION (00Z-24Z)... RAIN WILL MOVE ACROSS THE TAF SITES OVER THE NEXT FEW HOURS BUT CONDITIONS WILL REMAIN VFR THROUGH AT LEAST MID EVENING. KDAY WILL SEE P6SM SNOW FOR THE NEXT HOUR. A CLUSTER OF CONVECTION CLOSE TO THE SFC LOW IN SW INDIANA DOES CONTAIN SOME LIGHTNING...AND WILL MONITOR THIS TO SEE IF IT HOLDS TOGETHER AS IT PROGRESSES EASTWARD. AS LOW PRESSURE MOVES SE OF THE TERMINALS...CEILINGS WILL BECOME MVFR AS WINDS SHIFT NE AROUND 12 KTS. COLDER AIR BEHIND THE LOW WILL CAUSE A CHANGE OVER TO SNOW 06Z TO 10Z. CIGS WILL BECOME VFR 12Z-14Z...LIKELY SCATTERING OUT 16Z TO 19Z. && .PREVIOUS DISCUSSION... (ISSUED 245 PM EST THU MAR 16 2006) SHORT TERM (TONIGHT THROUGH SATURDAY NIGHT)... DECENT RETURNS SHOWING UP ON RADAR ACROSS NORTHERN OHIO BUT WITH DRY AIRMASS IN PLACE...IT APPEARS THAT THIS PCPN IS NOT REACHING THE GROUND (NOT SURE IF THE .12 REPORTED ON THE AOH OB THIS PAST HOUR WAS REAL). 12Z MODELS HAVE TRENDED SLIGHTLY FARTHER SOUTH WITH THE TRACK OF THE LOW OVERNIGHT TONIGHT...SPREADING PCPN DOWN ACROSS AREA THROUGH THIS EVENING. HOWEVER...AM CONCERNED ABOUT LARGE DRY SLOT ACROSS SOUTHERN ILLINOIS AND LATEST RUC SEEMS TO BE PICKING UP ON THIS...KEEPING MUCH OF SOUTHWEST FA MAINLY DRY TONIGHT. ISENTROPIC LIFT IS FORECAST TO INCREASE ON THE 290K-295 K SURFACES BETWEEN NOW AND 03Z AS SURFACE LOW MOVES FROM CENTRAL ILLINOIS INTO SOUTHERN INDIANA. AS A RESULT...EXPECT TO SEE PCPN BEGIN TO FILL IN A LITTLE FARTHER SOUTH THAN WHERE THINGS ARE CURRENTLY SHOWING UP ON RADAR. WITH THIS IN MIND...WILL STILL ALLOW FOR PCPN TO DEVELOP DOWN INTO FA THROUGH THIS EVENING...BUT WE COULD END UP WITH A FAIRLY SHARP SOUTHERN EDGE. WILL THEREFORE...ONLY GO WITH CHANCE POPS ACROSS THE SOUTHWEST. MODELS FAIRLY CONSISTENT SHOWING BOUNDARY LAYER COOLING OFF FROM NORTH TO SOUTH ACROSS THE AREA OVERNIGHT. BASED ON BLEND OF FORECAST SOUNDINGS FROM THE GFS AND NAM...EXPECT PCPN TO MIX WITH AND THEN CHANGE OVER TO SNOW ACROSS THE FAR NORTH LATE THIS EVENING AND THEN ACROSS CENTRAL PORTIONS OF FA AFTER MIDNIGHT. ACROSS THE FAR SOUTH...ANY CHANGEOVER WOULD BE LATE TONIGHT OR FRIDAY MORNING. SNOWFALL ACCUMULATIONS ARE PROBLEMATIC AS DRY AIR IN PLACE AND RELATIVELY WARM GROUND TEMPERATURES WILL LIKELY CUT BACK ON ANY ACCUMULATIONS. HOWEVER...THIS WILL BE COUNTERED BY THE FACT THAT THE SNOW WILL BE FALLING DURING THE NIGHTTIME PERIOD AND POSSIBILITY FOR SOME CONVECTIVE ENHANCEMENT. ACROSS THE FAR NORTH...WHERE CHANGEOVER SHOULD OCCUR THE EARLIEST...WILL GO WITH 1 TO 2 INCHES WITH UP TO AN INCH DOWN TO ABOUT I-70. FARTHER TO THE SOUTH...CHANGE OVER SHOULD BE LATE ENOUGH TO LIMIT ANY ACCUMULATIONS. WILL HANG ON TO SOME LOWER CLOUDS THROUGH THE MORNING ON FRIDAY WITH LINGERING LOWER LEVEL MOISTURE AND CAA. WILL ALSO UNDERCUT GUIDANCE TEMPS A FEW DEGREES FOR HIGHS FRIDAY. OTHERWISE...HIGH PRESSURE THEN BUILDS IN THROUGH THE REMAINDER OF THE SHORT TERM FOR QUIET WEATHER INTO THE WEEKEND. LONG TERM (SUNDAY THROUGH THURSDAY)... MODELS HAVE TRENDED STRONGER AND SLOWER WITH THE STORM SYSTEM EARLY NEXT WEEK. THIS SUPPORTS YESTERDAYS 12Z RUN WHICH WAS SLOWER WITH THE ONSET OF PCPN. THEREFORE DELAYED THE ONSET OF PCPN UNTIL MONDAY NIGHT. GFS HAS BEEN TRENDING FARTHER SOUTH WITH THE LOW. 06Z RUN HAS THE LOW IN CNTRL KY AT 12Z TUE...12Z GFS NOW HAS IT IN ERN TN. WENT A BLEND OF 06Z/12Z GFS RUNS...SO WAS COOLER THAN THE 00Z MEX FOR HIGHS TUE. THE BLEND OF THE THICKNESSES PUTS THE RAIN/SNOW LINE AROUND THE OHIO RIVER FOR TUE...BUT THEREFORE SHOULD BE A CHANGE OVER TO ALL SNOW ON THE BACKEDGE. LOW PULLS OF THE EAST COAST TUESDAY NIGHT. WITH COLD NW FLOW...MODELS ARE SUGGESTING THAT THERE MIGHT BE SOME LAKE EFFECT SHOWERS WED AND THU. OTHER THAN BEING COOLER WITH TUE MAXS...WENT CLOSE TO MEX NUMBERS. SITES && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 245 PM EST THU MAR 16 2006 .SHORT TERM (TONIGHT THROUGH SATURDAY NIGHT)... DECENT RETURNS SHOWING UP ON RADAR ACROSS NORTHERN OHIO BUT WITH DRY AIRMASS IN PLACE...IT APPEARS THAT THIS PCPN IS NOT REACHING THE GROUND (NOT SURE IF THE .12 REPORTED ON THE AOH OB THIS PAST HOUR WAS REAL). 12Z MODELS HAVE TRENDED SLIGHTLY FARTHER SOUTH WITH THE TRACK OF THE LOW OVERNIGHT TONIGHT...SPREADING PCPN DOWN ACROSS AREA THROUGH THIS EVENING. HOWEVER...AM CONCERNED ABOUT LARGE DRY SLOT ACROSS SOUTHERN ILLINOIS AND LATEST RUC SEEMS TO BE PICKING UP ON THIS...KEEPING MUCH OF SOUTHWEST FA MAINLY DRY TONIGHT. ISENTROPIC LIFT IS FORECAST TO INCREASE ON THE 290K-295 K SURFACES BETWEEN NOW AND 03Z AS SURFACE LOW MOVES FROM CENTRAL ILLINOIS INTO SOUTHERN INDIANA. AS A RESULT...EXPECT TO SEE PCPN BEGIN TO FILL IN A LITTLE FARTHER SOUTH THAN WHERE THINGS ARE CURRENTLY SHOWING UP ON RADAR. WITH THIS IN MIND...WILL STILL ALLOW FOR PCPN TO DEVELOP DOWN INTO FA THROUGH THIS EVENING...BUT WE COULD END UP WITH A FAIRLY SHARP SOUTHERN EDGE. WILL THEREFORE...ONLY GO WITH CHANCE POPS ACROSS THE SOUTHWEST. MODELS FAIRLY CONSISTENT SHOWING BOUNDARY LAYER COOLING OFF FROM NORTH TO SOUTH ACROSS THE AREA OVERNIGHT. BASED ON BLEND OF FORECAST SOUNDINGS FROM THE GFS AND NAM...EXPECT PCPN TO MIX WITH AND THEN CHANGE OVER TO SNOW ACROSS THE FAR NORTH LATE THIS EVENING AND THEN ACROSS CENTRAL PORTIONS OF FA AFTER MIDNIGHT. ACROSS THE FAR SOUTH...ANY CHANGEOVER WOULD BE LATE TONIGHT OR FRIDAY MORNING. SNOWFALL ACCUMULATIONS ARE PROBLEMATIC AS DRY AIR IN PLACE AND RELATIVELY WARM GROUND TEMPERATURES WILL LIKELY CUT BACK ON ANY ACCUMULATIONS. HOWEVER...THIS WILL BE COUNTERED BY THE FACT THAT THE SNOW WILL BE FALLING DURING THE NIGHTTIME PERIOD AND POSSIBILITY FOR SOME CONVECTIVE ENHANCEMENT. ACROSS THE FAR NORTH...WHERE CHANGEOVER SHOULD OCCUR THE EARLIEST...WILL GO WITH 1 TO 2 INCHES WITH UP TO AN INCH DOWN TO ABOUT I-70. FARTHER TO THE SOUTH...CHANGE OVER SHOULD BE LATE ENOUGH TO LIMIT ANY ACCUMULATIONS. WILL HANG ON TO SOME LOWER CLOUDS THROUGH THE MORNING ON FRIDAY WITH LINGERING LOWER LEVEL MOISTURE AND CAA. WILL ALSO UNDERCUT GUIDANCE TEMPS A FEW DEGREES FOR HIGHS FRIDAY. OTHERWISE...HIGH PRESSURE THEN BUILDS IN THROUGH THE REMAINDER OF THE SHORT TERM FOR QUIET WEATHER INTO THE WEEKEND. && .LONG TERM (SUNDAY THROUGH THURSDAY)... MODELS HAVE TRENDED STRONGER AND SLOWER WITH THE STORM SYSTEM EARLY NEXT WEEK. THIS SUPPORTS YESTERDAYS 12Z RUN WHICH WAS SLOWER WITH THE ONSET OF PCPN. THEREFORE DELAYED THE ONSET OF PCPN UNTIL MONDAY NIGHT. GFS HAS BEEN TRENDING FARTHER SOUTH WITH THE LOW. 06Z RUN HAS THE LOW IN CNTRL KY AT 12Z TUE...12Z GFS NOW HAS IT IN ERN TN. WENT A BLEND OF 06Z/12Z GFS RUNS...SO WAS COOLER THAN THE 00Z MEX FOR HIGHS TUE. THE BLEND OF THE THICKNESSES PUTS THE RAIN/SNOW LINE AROUND THE OHIO RIVER FOR TUE...BUT THEREFORE SHOULD BE A CHANGE OVER TO ALL SNOW ON THE BACKEDGE. LOW PULLS OF THE EAST COAST TUESDAY NIGHT. WITH COLD NW FLOW...MODELS ARE SUGGESTING THAT THERE MIGHT BE SOME LAKE EFFECT SHOWERS WED AND THU. OTHER THAN BEING COOLER WITH TUE MAXS...WENT CLOSE TO MEX NUMBERS. SITES && .AVIATION (18Z-18Z)... VFR CONDITIONS WILL CONTINUE INTO THE EVENING. EXPECT RAIN TO DEVELOP AND SPREAD INTO THE TAF SITES NEAR OR SHORTLY AFTER 00Z WITH LITTLE OR NO RESTRICTION TO VISIBILITY. CEILINGS WILL LOWER BY THIS TIME BUT STILL BE VFR. AS LOW PRESSURE MOVES EAST OF THE TERMINALS EXPECT CEILINGS TO BECOME MVFR. COLDER AIR WILL CAUSE A CHANGE OVER TO SNOW AT ALL BUT CINCINNATI BEFORE THE PRECIPITATION TAPERS OFF. THERE COULD BE SOME LINGERING FLURRIES ASSOCIATED WITH A TROUGH TRAILING THE LOW PRESSURE SYSTEM. DRIER AIR WILL MOVE IN AFTER 12Z RESULTING IN CEILING LIFTING BACK TO VFR AND SOME LOCATIONS MAY BECOME SCATTERED BEFORE THE END OF THE FORECAST PERIOD. && && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORMAN OK 903 PM CST THU MAR 16 2006 VERY DRY/STABLE POST-FRONTAL AIR RESIDES OVER THE FORECAST AREA AT THIS TIME WITH DEWPOINTS IN THE TEENS AND 20S RESULTING IN HUMIDITIES BETWEEN 20 AND 30 PERCENT. A SLOW RISE IN DEWPOINTS SHOULD OCCUR OVERNIGHT AS THE FLOW GRADUALLY VEERS BUT VALUES SHOULD STILL REMAIN QUITE LOW EVEN THROUGH THE DAY ON FRIDAY. 12Z NAM/GFS 12 HR FORECASTS VALID 00Z WERE ABOUT 10 DEGREES TOO MOIST WITH THE DEWPOINTS. THE LATEST FSL RUC INITIALIZES THESE LOW VALUES MUCH BETTER AND HAVE USED IT AS GUIDANCE FOR LOWERING DEWPOINTS OVERNIGHT AND ALSO THROUGH THE DAY ON FRIDAY. FIRE WEATHER CONCERNS FRIDAY SHOULD STILL REMAIN AT OR BELOW THE HIGH CATEGORY HOWEVER AS INSOLATION WILL BE LIMITED WITH INCREASING CLOUDS ALONG WITH LIGHT EASTERLY WINDS. OTHERWISE...THE STAGE IS SET FOR A SIGNIFICANT RAIN EVENT THIS WEEKEND WITH ONE OR MORE ROUNDS OF RAIN EXPECTED. THE THERMODYNAMIC PROFILE IS ALREADY FAVORABLE FOR ISENTROPIC UPGLIDE DUE TO A CONSIDERABLE TEMPERATURE GRADIENT NORTH OF THE SURFACE COLD FRONT IN TEXAS UP TO ABOUT 650 MB. AIRMASS REMAINS EXTREMELY DRY AT THE MOMENT BUT THAT WILL CHANGE SOON AS HIGH BASED MOISTURE RESIDING NEAR THE GULF BEGINS ITS NORTHWARD TRANSPORT EARLY FRIDAY WITH THE FIRST ROUND OF PRECIPITATION ARRIVING FRIDAY NIGHT. THE EXACT TIMING AND SUBSEQUENT AMOUNT OF PRECIPITATION THIS WEEKEND WILL LARGELY DEPEND ON THE TRACK AND SPEED OF A COMPLEX UPPER TROUGH EVOLVING OVER THE EASTERN PACIFIC. 18Z MODELS ALREADY BACKED OFF ON ITS SPEED A LITTLE BIT THIS WEEKEND COMPARED TO THE 12Z MODELS AS A SUBSTANTIAL REGION OF DARKENING ON WATER VAPOR IMAGERY AND ASSOCIATED STRONG UPPER LEVEL WINDS APPROACH THE BASE OF THE TROUGH. THE NEW 00Z NAM CONTINUES THIS TREND AS WELL...DEPICTING THE DEVELOPING LOW A BIT FARTHER SOUTHWEST OF EARLIER FORECASTS... RESULTING IN ABOUT A 6 HR DIFFERENCE IN ARRIVAL. OVERALL DIFFERENCES APPEAR INSIGNIFICANT AT THIS TIME...BUT WILL NEED TO MONITOR FOR POSSIBLE SLOWER/MORE SOUTHWARD PATH. A SPECIAL WEATHER STATEMENT WAS ISSUED LATE THIS AFTERNOON TO HIGHLIGHT THE RAIN EVENT THIS WEEKEND WITH FORECAST AMOUNTS LIKELY EXCEEDED WHAT HAS BEEN RECEIVED IN SOME AREAS FOR THE LAST 6 MONTHS...ESPECIALLY IN THE WEST. CAN NOT RULE OUT SEVERE THUNDERSTORMS AS SOME POINT THIS WEEKEND AS WELL. WIND PROFILES REMAIN FAVORABLE FOR ORGANIZED DEVELOPMENT FOR QUITE A LONG PERIOD OF TIME. THE MAIN ISSUE IS WHETHER OR NOT ENOUGH INSTABILITY CAN WORK ITS WAY INTO THE FORECAST AREA. HIGH BASED INSTABILITY THAT WOULD SUPPORT MAINLY HAIL IS POSSIBLE NEAR THE RED RIVER FRIDAY NIGHT AND AGAIN SATURDAY NIGHT. SEVERE WEATHER CONCERNS MAY VERY WELL CONTINUE SUNDAY IN THE SOUTHWEST AND OVER THE SOUTHERN THIRD OR SO OF THE AREA AGAIN ON MONDAY AS LOWER LEVEL MOISTURE INCREASES AHEAD OF THE APPROACHING UPPER LOW. TOO EARLY TO IDENTIFY ALL THE DETAILS...BUT WILL WATCH CAREFULLY. JAMES ------------------------- 332 PM CST THU MAR 16 2006 .DISCUSSION... HAVE GENERALLY CONTINUED WITH THE THINKING OF THE PAST SEVERAL DAYS. BASICALLY... A LARGE STORM SYSTEM IS FORECAST TO APPROACH THE SOUTHERN PLAINS THIS WEEKEND... BRINGING OUR FIRST CHANCE AT SUBSTANTIAL RAIN IN QUITE SOME TIME. AS THE STORM SYSTEM PARKS OVER THE REGION... WAVES OF RAIN ARE EXPECTED ACROSS NORTH TEXAS AND OKLAHOMA... WITH TOTAL AMOUNTS PROBABLY IN EXCESS OF 1 INCH AT MOST LOCATIONS IN THE EASTERN 2/3 OF OKLAHOMA. AFTER SUNDAY... THERE IS SOME DISAGREEMENT BETWEEN THE ECMWF AND GFS. THE FORMER TAKES THE UPPER SYSTEM FARTHER NORTH THAN THE GFS. OUR PREVIOUS FORECAST IS BETWEEN THESE TWO SOLUTIONS AND STILL LOOKS REASONABLE. THE SYSTEM IS EXPECTED TO PULL AWAY TO THE NORTHEAST MONDAY INTO TUESDAY... GRADUALLY REDUCING PRECIPITATION CHANCES FROM SOUTHWEST TO NORTHEAST. ON MONDAY NIGHT... IT LOOKS LIKE THE TEMPERATURE PROFILE WILL SUPPORT SNOW... EVEN IF ONE MAKES APPROPRIATE ADJUSTMENTS TO THE GFS FORECAST SOUNDINGS. OUR CURRENT FORECAST OF RAIN OR SNOW IN THE NORTH HALF OF OKLAHOMA STILL LOOKS GOOD. QUIET... BUT SOMEWHAT COOL... WEATHER IS DUE TO BE THE THEME OF THE MIDDLE OF NEXT WEEK. AS SUGGESTED ABOVE... RATHER FEW CHANGES HAVE BEEN MADE TO THE FORECAST THIS TIME AROUND. POPS WERE LOWERED SOME FOR TOMORROW DUE TO A FAIRLY THICK LAYER OF VERY DRY AIR NEAR THE SURFACE... SO WE EXPECT A LOT OF VIRGA AND VERY LITTLE RAIN UNTIL THE LOWER ATMOSPHERE MOISTENS SUBSTANTIALLY FRIDAY NIGHT. A FEW TEMPERATURE FORECASTS WERE ALTERED... THE MOST SIGNIFICANT WAS FOR WARMER READINGS SATURDAY NIGHT AS THICK CLOUDS AND VERY MOIST AIR WILL MINIMIZE DIURNAL CHANGES. OUR RED FLAG WARNING WILL EXPIRE MOMENTARILY AND WE DO NOT PLAN TO EXTEND IT... SINCE WINDS SHOULD DIMINISH FAIRLY QUICKLY OVER THE NEXT COUPLE OF HOURS. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 35 51 40 45 / 0 20 60 80 HOBART OK 35 51 42 46 / 10 30 50 70 WICHITA FALLS TX 39 56 45 49 / 10 30 60 80 GAGE OK 31 47 37 45 / 10 20 40 50 PONCA CITY OK 31 49 36 44 / 0 10 60 70 DURANT OK 40 60 43 48 / 0 10 70 80 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...RED FLAG WARNING UNTIL 4 PM CST THIS AFTERNOON FOR OKZ004-OKZ005- OKZ006-OKZ007-OKZ008-OKZ009-OKZ010-OKZ011-OKZ012-OKZ013- OKZ014-OKZ015-OKZ016-OKZ017-OKZ018-OKZ019-OKZ020-OKZ021- OKZ022-OKZ023-OKZ024-OKZ025-OKZ026-OKZ027-OKZ028-OKZ029- OKZ030-OKZ031-OKZ032-OKZ033-OKZ034-OKZ035-OKZ036-OKZ037- OKZ038-OKZ039-OKZ040-OKZ041-OKZ042-OKZ044-OKZ045-OKZ046- OKZ050. TX...RED FLAG WARNING UNTIL 4 PM CST THIS AFTERNOON FOR TXZ083-TXZ084- TXZ085-TXZ086-TXZ087-TXZ088-TXZ089-TXZ090. && $$ 23/25 ok AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 936 PM EST THU MAR 16 2006 .SHORT TERM (REST OF TONIGHT THROUGH FRIDAY)... ADJUSTED PROBABILITIES AND AMOUNTS OF SNOW BASED ON RECENT RADAR AND SURFACE DATA AND RUC MODEL RUNS. THE TREND CONTINUES TO BE FOR SNOW BAND ASSOCIATED WITH LOW PRESSURE SYSTEM TO BE SHIFTING TOWARD THE SOUTH. SO ACCUMULATIONS SHOULD BE MAINLY LIMITED TO LOCATIONS SOUTH OF INTERSTATE 70. LOWLANDS TO GET UP TO ABOUT AN INCH. MOUNTAINS CAN POSSIBLY STILL GET 2 TO 4 INCHES. && .PREVIOUS DISCUSSION... (ISSUED 310 PM EST THU MAR 16 2006) SHORT TERM (TONIGHT THROUGH FRIDAY)... LOW PRESSURE AREA AND ASSOCIATED PCPN/CLOUDINESS ARE APPROACHING FROM THE WEST. SOUTHERN THIRD OF OUR CWA IS ON THE NRN EDGE OF PCPN SHIELD AS LOW PASSES TO OUR SOUTH. NAM40 TIME HEIGHT CROSS SECTIONS INDICATE BEST LIFT AND SNOW POTENTIAL FOR KZZV 04Z-09Z FRI, KMGW 07Z-11Z, KPIT 09Z-12Z AND TUCKER CTY WV 06Z-14Z WITH ADDED OROGRAPHIC INFLUENCES. ENSEMBLE SREF PLUME FORECASTS CONSISTENT IN KEEPING ABOUT AN INCH OF SNOW IN KPIT AREA, LESS AMTS NORTH OF KPIT AND HIGHER AMOUNTS SOUTH OF KPIT. OF COURSE SOME SOLUTIONS ARE ZERO FOR THE PITTSBURGH AREA. WWD CHOSE A COMPROMISE SOLUTION WITH THE 1-2 INCH LINE AS FAR NORTH AS KPIT AND AS MUCH AS 6 INCHES OVER TUCKER COUNTY WV. AT ANY RATE DEPENDING ON WHICH MODEL YOU SELECT YOU CAN PRETTY MUCH FIND A SOLUTION THAT YOU CAN LIVE WITH. WE DECIDED THE WWD SOLUTION WAS A REASONABLE COMPROMISE. THE OVERRIDING FACTOR IS THAT THIS IS A FAST MOVING SYSTEM. TO SUM IT UP WE ARE GOING WITH A SNOW ADVISORY FOR TUCKER AND PRESTON COUNTIES WV AND GARRETT COUNTY MD FROM 1AM-10AM FRIDAY. LONG TERM (FRIDAY NIGHT THROUGH THURSDAY) AS HIGH BEGINS TO BUILD IN FRIDAY NIGHT AND SATURDAY BEHIND EXITING STORM...WINDS BECOME MORE NORTHWEST AND FLOW MORE CYCLONIC. CLOUDS INCREASE SATURDAY WITH SNOW SHOWERS/FLURRIES POSSIBLE ACROSS NORTHWEST PENNSYLVANIA AND IN MOUNTAINS. SOME CLEARING AS FLOW RELAXES ON SUNDAY AND MOSTLY SUNNY SKIES BY MONDAY WITH RIDGE OVER UPPER OHIO VALLEY. GFS MUCH STRONGER THAN ECMWF WITH STORM MOVING INTO REGION TUESDAY AND PULLS WARM AIR FARTHER NORTH THAN ECMWF. CRITICAL THICKNESSES REMAIN BELOW 1300 METERS ON GFS SO WILL GO WITH SNOW FOR NOW. COLD AIR AND CYCLONIC FLOW SHOULD KEEP CHANCE SNOW SHOWERS IN AREA THROUGH DAY 7. AVIATION... OVER THE SOUTHERN HALF OF CWA A GENERAL LOWERING OF CIGS AND VSBYS AS A LOW PRESSURE AREA APPROACHES FROM THE WEST AND MOVES TO OUR SOUTH. FROM KPIT-KZZV AND SOUTH VFR CIGS/VSBYS TIL LATER THIS EVENING/EARLY MORNING HOURS OF FRIDAY THEN CIGS/VSBYS LOWERING TO MVFR WITH IFR AREAS IN SNOW AND FOG. FOR KDUJ AND KFKL VFR CONDS TIL 08Z. AFT 08Z SCATTERED MVFR CIGS AND VSBYS IN -SN BR. CONDS IMPROVE TO VFR ACROSS THE BOARD AFT 12Z FRIDAY AS LOW PRESSURE AREA RAPIDLY MOVES TOWARD THE EAST COAST. SURFACE WIND SPEEDS 5 TO 15KTS WITH DIRECTION VEERING FROM NNE TO NW AS THE LOW PASSES TO OUR SE. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...SNOW ADVISORY FOR MDZ001 FROM 1 AM FRIDAY TO 10 AM FRIDAY. OH...NONE. PA...NONE. WV...SNOW ADVISORY FOR WVZ023-041 FROM 1 AM FRIDAY TO 10 AM FRIDAY. && $$ pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 805 PM CST THU MAR 16 2006 .UPDATE...WILL BE UPDATING TO RAISE POPS OVERNIGHT. FRONT HAS PUSHED TO THE SOUTH OF I-10 THIS EVENING. ABOVE THE SURFACE FRONT...AREA OF ACCAS DEVELOPED ALONG THE 850 MB FRONT. TCU DEVELOPED RIGHT AT SUNSET ALONG THIS MID LEVEL BOUNDARY AND RADAR ECHOES WERE NOTED. THESE HAVE SINCE DISSIPATED...BUT IS A GOOD INDICATION OF THE GOOD INSTABILITY DERIVED FROM THE ELEVATED PARCELS. MUCAPES FROM THE RUC CURRENTLY RUNNING AROUND 1500 J/KG ALONG THE BOUNDARY. THIS AREA IS FORECAST TO LIFT NORTHWEST OVERNIGHT AND INTENSIFYING LOW LEVEL JET WILL HELP TO ISENTROPICALLY LIFT PARCELS ABOVE THE STABLE BOUNDARY LAYER. RAINFALL AMOUNTS SHOULD BE LIGHT TONIGHT WITH THE DRY SUB-CLOUD LAYER...HOWEVER ELEVATED CONVECTION COULD BECOME STRONG WITH MARGINALLY SEVERE HAIL AND EVENTUALLY HEAVIER RAINS IN THE MOST INTENSE CONVECTION. AT THIS TIME TEMPERATURES LOOK OKAY AND WILL ONLY BE TWEAKING THE POPS AT THIS TIME. BRAZZELL && .PREV DISCUSSION... (ISSUED 520 PM CST THU MAR 16 2006) AVIATION... EXPECT VFR CONDITIONS TO CONTINUE OVER THE NEXT 24 HOURS. AT TERMINAL KABI THE NORTHERLY WINDS WILL SLOWLY SHIFT TO THE EAST/NORTHEAST THIS EVENING. AT BOTH KABI AND KSJT WINDS WILL REMAIN AT OR BELOW 10 KTS OVERNIGHT. AFTER 11Z/17 WINDS WILL INCREASE TO AROUND 15 KTS. PREV DISCUSSION... (ISSUED 317 PM CST THU MAR 16 2006) SHORT TERM... FRONTAL BOUNDARY HAS PROGRESSED SOUTH TO THE INTERSTATE 10 CORRIDOR THIS AFTERNOON WITH DEWPOINTS IN THE TEENS FROM THE CENTRAL CWA NORTH .ABOUT TEN DEGREES COOLER THAN THE LATEST GFS. THE FRONT SHOULD STALL SOMEWHERE SOUTH OF INTERSTATE 10 THIS EVENING WITH A SLIGHT CHANCE OF SHOWERS ALONG THE BOUNDARY. BOUNDARY SHOULD REMAIN ALONG SOUTHERN PERIFERY OF THE CWA INTO FRIDAY AS AN UPPER TROUGH AXIS DIGS SOUTH ALONG THE PACIFIC COAST. AS DISTURBANCES TRACK NORTHEAST OVER CENTRAL TEXAS AHEAD OF THE UPPER LEVEL TROUGH AND A DEVELOPING LLJ PUSHES GULF MOISTURE OVER THE BOUNDARY...WILL SEE AN INCREASING POSSIBILITY OF SHOWERS AND THUNDERSTORMS DEVELOPING INTO FRIDAY EVENING AND OVERNIGHT FRIDAY. LONG TERM... FRONTAL BOUNDARY WILL BEGIN EDGING NORTHWARD AHEAD OF THE APPROACHING UPPER LEVEL TROUGH WITH THE BEST CHANCE OF RAINFALL OVER THE NORTHERN CWA INTO THIS WEEKEND. DRYLINE WILL REMAIN WEST OF THE CWA UNTIL LATE SUNDAY WHEN IT WILL BE PUSHED EAST BY THE APPROACHING STORM SYSTEM. TIMING WILL BE CRITICAL AS TO EXTENT AND SEVERITY OF ANY ASSOCIATED STORMS ON SUNDAY. IT APPEARS NOW THAT DRYLINE PASSAGE WILL BE LATE SUNDAY INTO MONDAY MORNING WITH THE BEST CHANCE OF THUNDERSTORMS DEVELOPING ALONG AND EAST OF THE DRYLINE/FRONT OVER THE BIG COUNTRY AREA AND MOVING VERY QUICKLY TO THE NORTHEAST. THE ASSOCIATED TRIPLE POINT IS PROGD TO BE OVER SOUTHEAST OKLAHOMA BY EARLY MONDAY MORNING WITH RAPID DRYING FROM WEST TO EAST OVER THE CWA. THE PREVIOUS GFS HAD AN UPPER LOW TRACKING INTO CENTRAL TEXAS ON FRIDAY...LATEST RUN HAS AN UPPER RIDGE OVER THE CENTRAL STATES WITH A DEVELOPING TROUGH ALONG THE PACIFIC...WILL LEAVE THE EXTENDED DRY. SJT WATCHES/WARNINGS/ADVISORIES... NONE. $$ && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 27/27 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 952 PM EST THU MAR 16 2006 .SHORT TERM (REST OF TONIGHT)... CURRENT SURFACE ANALYSIS SHOWS 1011 MB SURFACE LOW ALONG THE IN/KY BORDER. A WARM FRONT EXTENDS E THROUGH SRN VA...THOUGH B/C OF THE LACK OF CLOUD COVER AND RADIATIONAL COOLING...THERE IS NOT MUCH DISPARITY IN TEMPS N-S OF THIS FRONT. DO NOT PLAN ON MAKING MANY CHANGES TO THE CURRENT FORECAST. DEEPER LAYERED CLOUD COVER N OF THE LOW/WARM FRONT STILL APPEARS AS IF IT WILL BRUSH OUR FAR NRN COUNTIES (ESP MD ERN SHORE BORDERING DE)... BASED ON THE LATEST TRENDS AND RUC PROJECTIONS. THIS AS THE WEAK SFC LOW MOVES E/ESE TO THE VA/NC COASTAL BORDER AROUND 12Z. RUC MODEL SOUNDINGS SHOW AN ABSENCE OF DEEP MOISTURE IN THE LOWER LAYERS (BELOW 8-10KFT) ACROSS MUCH OF THE REGION...WITH THE EXCEPTION BEING OVER THE FAR NRN AREAS WHERE A SLIGHTLY MORE FVRBL MOISTURE PROFILE EXTENDS DOWN TO 850 MB OR AROUND 4-5 KFT. STILL...EVEN IN THESE AREAS (INCLUDING SBY)...AIRMASS BELOW 850 MB REMAINS ON THE DRY SIDE THROUGH 12Z. IN LIGHT OF THIS...WILL CONTINUE WITH THE 30-40% POPS AT MOST ACROSS THE NRN PTNS OF THE FCST AREA...20% OR LESS SOUTH (SPRINKLES AT MOST). WILL ALSO LEAVE IN MENTION OF SNOW OR RAIN SHOWERS OVER THE FAR NRN PTN...WHERE WET BULB 0C HEIGHTS ARE EXPECTED TO FALL AOB 1KFT. REGARDLESS...THE LIGHT INTENSITY OF PRECIP WILL LIMIT THE EVAP COOLING POTENTIAL IN THE BNDRY LAYER...SO WOULD MORE LIKELY SEE A SCENARIO WITH MORE RAIN VS. SNOW...OR PERHAPS A PERIOD OF LIGHT SLEET. FORECAST UPDATES WILL BE FORTHCOMING (AROUND 10 PM). LITTLE OR NO CHANGE TO THE PREVIOUS MARINE FORECAST. && .PREVIOUS DISCUSSION... (ISSUED 420 PM EST THU MAR 16 2006) LONG TERM /MONDAY THROUGH THURSDAY/...NEXT DISTURBANCE MOVES INTO CNTRL/SRN PLAINS...EVENTUALLY BRINGING SW FLOW IN MID LVLS TO OUR REGION BY MON NGT. THIS WOULD HELP DRIVE SOME GULF MSTR INTO THE REGION...POSSIBLY BRINGING SOME BADLY NEEDED PRECIP (SEE CLIMATE/FIRE WX SECTIONS). GFS/ECMWF SHOW 1ST SFC LOW TRACKING W OF THE MTNS WITH SECONDARY LOW ACRS CAROLINAS TUE. GFS IS COLDER SOLN AND GIVES MUCH OF THE CWA SNOW. HAVE GNRLY FAVORED A SOLN A LITTLE WARMER THAN THE GFS FOR NOW GIVEN THE TIME OF YEAR...KEEPING SNOW N AND W OF RICHMOND WITH JUST COLD RAIN ELSEWHERE. WILL CONTINUE TO MONITOR TRENDS WITH THIS. MARINE... GOING WITH A MARGINAL SMALL CRAFT ADVISORY ALL AREAS BEGINNING LATE FRI MORN. PGRAD TIGHTENS ALONG COAST AS LOW MOVES OFF NORTHERN OBX AND DEEPENS BY MIDDAY. MAY BE A BRIEF LULL IN WINDS FRI EVE THEN PICKS UP AGAIN AS CAA SURGE KICKS IN LATE FRI NIGHT INTO EARLY SAT. MODERATE NW FLOW WILL DOMINATE MUCH OF UPCOMING WEEKEND SO LESS THAN IDEAL BOATING CONDS EXPECTED. AVIATION... GRADUALLY LOWERING CLOUD BASES TNGT AS BAND OF MOISTURE NORTH OF WEAK LOW PRES TRACK APPROACHES. MOST TAF SITES EXPECTED TO REMAIN VFR EXCEPT PSBL MVFR CIGS/VSBYS AT NORTHERN TERMINALS (SBY/RIC) CLOSER TO DEEPER MOISTURE/LIGHT PCPN BAND. FIRE WEATHER...VERY DRY RIGHT NOW...BUT WITH MUCH LESS WIND THAN YSDY. ANY PRECIP OVERNGT/FRI MRNG WILL BE LGT...GNRLY .10 INCHES OR LESS. NOT AS DRY FRI AS WIND FLOW NLY INSTEAD OF NW DOWNSLOPING. DRIER AGAIN SAT/SUN BUT WITH COOL TEMPS IN UPR 40S TO MID 50S. CLIMATE...ASSUMING NO PRECIP AT RIC THROUGH MIDNIGHT...DRY STRETCH HAS NOW REACHED 21 CONSECUTIVE DAYS WITH NO MSRBL PRECIP (A FEW DATES THIS MONTH HAVE SEEN A TRACE). THIS IS THE 2ND LONGEST STREAK ON RECORD AT RIC FOR FEB/MAR (LONGEST WAS 26 DAYS IN A ROW FEB 3RD THROUGH FEB 28TH 1968). AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FOR ANZ630>633-650-652-654-656-658 FROM 11 AM FRIDAY TO 6 AM SATURDAY. $$ SHORT TERM UPDATE...HURLEY REST OF SHORT TERM/LONG TERM/CLIMATE...BROWN AVIATION/MARINE...HURLEY/CROSSLEY $$ va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSONVILLE FL 210 AM EST FRI MAR 17 2006 ...A FEW SPRINKLES REMAIN POSSIBLE THROUGH MID-MORNING... .SHORT TERM...RUC ANALYSIS SHOWS SHORT WAVE TROUGH ALIGNED WEST TO EAST AND ROUGHLY ALONG THE GEORGIA/FLORIDA STATE LINE. EXTENSIVE CLOUD DECK EXISTS FROM NORTH GEORGIA THROUGH THE NORTHERN SECTIONS OF THE FORECAST AREA. MOISTURE BELOW 800 MB IN THESE AREAS IS VERY LOW WITH DEW POINT DEPRESSIONS GREATER THAN 25 DEGREES JUST OFF THE SURFACE. THIS LEADS TO GREATER CONFIDENCE THAT SHORT TERM GRIDS ARE ON TRACK FOR SILENT POPS. THERE IS SOME SLIGHTLY MOISTER AIR OVER SOUTHERN SECTIONS OF THE CWA AND AS SHORTWAVE SINKS SOUTHWARD...A FEW SPRINKLES WILL BE POSSIBLE OVER THESE AREAS. ALTHOUGH THE FLOW ALOFT WILL BECOME NORTHWEST BY EARLY AFTERNOON...SURFACE FLOW WILL REMAIN WESTERLY IN THE WAKE OF SURFACE LOW OFF THE CAROLINA COAST. THIS WILL RESULT IN A CONTINUATION OF WARM TEMPERATURES AREA WIDE WITH SOUTHERN SECTIONS NEARING THE 80 DEGREE MARK. COLD AIR ADVECTION COMMENCES OVER THE GEORGIA PORTION AROUND 06Z TONIGHT WHILE THE FLORIDA PORTION IS DELAYED LARGELY UNTIL SATURDAY. THIS WILL RESULT IN COOLER TEMPS OVER THE GEORGIA PORTION FRIDAY NIGHT BUT SIMILAR VALUES TO TONIGHTS OVER THE FLORIDA PORTION. VERY QUICK SHOT OF COOLER AIR WILL BRING MAX TEMPS FOR SAT TO BELOW NORMAL FOR ALL AREAS...ESPECIALLY ALONG THE COAST WHERE NORTHEAST FLOW WILL KEEP TEMPS DOWN. NEARLY IDEAL ISENTROPIC LIFT CONDITIONS TO SET UP OVER THE CENTRAL PLAINS AS STRONG HIGH PRESSURE RIDGES DOWN THE CENTRAL SECTIONS OF THE COUNTRY WHILE BROAD SOUTHWEST FLOW ALOFT RIDES UP AND OVER COLD DOME. WITH TIME...THIS HIGH PRESSURE RIDGE WILL BUILD SOUTHEAST...BUT INITIALLY FLOW ALOFT REMAINS NORTHWEST. GRADUALLY FLOW BELOW 500MB BECOMES MORE WESTERLY...AND CROSS SECTIONS INDICATE MODEST CROSS ISOTHERMAL FLOW. GFS IS MUCH MORE AGGRESSIVE WITH THIS FEATURE WITH 5 UNITS OF ADIABATIC OMEGA ALONG AND NORTH OF THE GEORGIA PORTION OF THE FORECAST AREA. WITH AXIS LARGELY NORTH OF THE AREA HOWEVER...WILL BLEND HIGHER MAV NUMBERS WITH THE MET TO RESULT IN LOW END SCATTERED POPS FOR GEORGIA. MY LAST POP GRID OF THE SHORT TERM MATCHES UP VERY WELL WITH INITIAL LONG TERM GRID CREATED BY PREVIOUS FORECASTER. WILL THEREFORE LEAVE MONDAY POPS AS THEY ARE FOR POSSIBLE MODIFICATION BY DAY SHIFT. .LONG TERM...STRONG LOW PRESSURE DEVELOPS OVER ARKANSAS ON MONDAY WITH WARM FRONT WELL NORTH OF THE AREA. COLD FRONT TO PUSH THROUGH ON TUESDAY WITH DRIER CONDITIONS EXPECTED THROUGH MID- WEEK. HAVE INCREASED MAX TEMPS TO BE IN LINE WITH NEWEST MEX IN WARM SECTOR MONDAY BUT NO OTHER CHANGES WILL BE MADE. && .MARINE...NE WINDS INCREASE SAT. STILL LOOKS CLOSE FOR SMALL CRAFT ADVISORY CONDITIONS AND WILL ERR ON THE SIDE OF CAUTION AND HOIST AN ADVISORY FOR THE GA OFFSHORE ZONES. ADVISORY CONDITIONS SHOULD BE SHORT-LIVED...WITH A RETURN EXPECTED BY TUE. && .FIRE WEATHER...VERY TRICKY FCST FOR TODAY. BOTH GFS AND NAM MOS A BIT HIGHER WITH DEW POINT VALUES TODAY. AS A RESULT...ONLY GET RH VALUES INTO THE UPPER 30S. HOWEVER...ONLY NEED ONE OB WITH 35 PERCENT TO COINCIDE WITH SUSTAINED WIND OF 15 MPH. CONCERN IS THAT MID-AFTN WIND SURGE ALONG WITH INCREASED DRY AIR ADVECTION WILL BRING A BRIEF PERIOD OF RED FLAG CONDITIONS FOR EXTREME N FL ZONES. HOWEVER...BASED ON MY LATEST GRIDS...CAN'T JUSTIFY A WARNING AND WILL CANCEL THE WATCH. POTENTIAL FOR A BUST IS THERE...AND DAY SHIFT MAY HAVE TO CHANGE COURSE. WILL INDICATE UNCERTAINTY IN FWF. WILL ISSUE A FIRE WX WATCH FOR W FL ZONES FOR SAT AFTN. THANX FOR COORD TAE/TBW/MLB! && .PRELIMINARY POINT TEMPS/POPS... AMG 77 48 69 46 / 0 0 0 10 SSI 77 51 66 49 / 0 0 0 10 JAX 79 53 68 49 / 0 0 0 0 SGJ 78 56 68 53 / 0 5 0 0 GNV 80 51 75 49 / 5 0 0 0 OCF 80 52 77 51 / 10 0 0 0 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...FIRE WEATHER WATCH FROM NOON TO 5 PM SAT FOR THE FOLLOWING ZONES: ALACHUA...COLUMBIA...GILCHRIST...HAMILTON...MARION... AND SUWANNEE. GA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 10 AM TO 4 PM SAT FOR THE FOLLOWING ZONES: ALTAMAHA SOUND TO FERNANDINA BEACH 20 TO 60 NM OFFSHORE. && $$ PUBLIC...DEESE MARINE/FIRE WX...CARROLL fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DODGE CITY KS 247 AM CST FRI MAR 17 2006 .DISCUSSION... DAYS 1-2... STRATUS IS SLOWLY OOZING SOUTHWEST TOWARD THE CWA THIS MORNING WHILE ROCKY MOUNTAIN INDUCED CIRRUS CONTINUES TO SPREAD ACROSS THE AREA. THE MID LEVEL FRONT WAS SOUTH OF KS ON THE 00Z ANALYSIS AND THIS MAY BRING A SMALL CHANCE OF SHOWERS THIS AFTERNOON AND TONIGHT ACROSS THE SOUTH AND EAST AS IT RETURNS NORTH AS A WARM FRONT. LOW LEVEL WARM ADVECTION OVER THE SURFACE COLD DOME WILL BEGIN TO INCREASE SATURDAY INTO SATURDAY NIGHT AND WILL BRING INCREASING RAIN CHANCES...ESPECIALLY THE FARTHER EAST YOU GO. HIGHS TODAY WILL BE TRICKY WITH THE CLOUD COVER...I.E. HOW FAR WEST DOES THE STRATUS MAKE IT AND WHEN WILL IT DISSIPATE AND WHAT AFFECT WILL THE CIRRUS HAVE. WILL BASE HIGHS TODAY FROM THE LATEST RUC FORECASTS WHICH ARE FAIRLY CLOSE TO MET GUIDANCE. A STRONG SOUTHEAST BREEZE TONIGHT ALONG WITH INCREASING MOISTURE WILL KEEP LOWS UP. WHATEVER WARMING WE DO ON SATURDAY WILL BE PURELY BY WARM AND MOIST ADVECTION AS THE LIKELIHOOD OF SEEING THE SUN IS SMALL. LOWS SATURDAY NIGHT WILL BE EVEN MILDER WITH CLOUDY SKIES AND HIGHER DEWPOINTS. DAYS 3-7... ECMWF HAS BEEN FAIRLY CONSISTENT COMPARED TO THE GFS ON UPCOMING SYSTEM FOR SUNDAY INTO MONDAY. GFS STILL MUCH FASTER BRINGING UPPER SYSTEM THROUGH CENTRAL PLAINS THAN THE ECMWF. GFS ALSO DOES NOT BRING A CLOSED LOW OUT OF THE ROCKIES AND CLOSES OFF THE SYSTEM OVER SERN KS MONDAY AFTERNOON. GFS SEEMS A LITTLE TOO SLOW CUTTING OFF THE LOW GIVEN AMOUNT OF ENERGY COMING AROUND BASE OF TROUGH AS IT CROSSES THE CONTINENTAL DIVIDE. SLOWER ECMWF SEEMS MORE REASONABLE...ESPECIALLY SINCE KICKER DOES NOT MAKE IT TO THE WEST COAST UNTIL 00Z-12Z TUE. THIS WILL BRING A CHANCE FOR SHOWERS TO THE CWA SUNDAY. MODELS ALSO BRINGING IN SOME DRIER LOW LEVEL AIR TO SOUTHWEST KS DURING THE DAY SUNDAY WHICH SHOULD ALLOW FOR SOME BETTER HEATING AND MORE INSTABILITY...SO PUT IN SOME THUNDERSTORMS FOR THE AFTERNOON AND EVENING OVER WESTERN ZONES. UPPER LOW AND SURFACE LOW FORECAST TO BE OVER SW KS EARLY MONDAY WITH COLDER AIR FILTERING IN FROM THE NORTH OVERNIGHT. CHANGED PRECIP OVER TO ALL SNOW NORTHERN HALF OF CWA BY 12Z MONDAY AND THEN ACROSS ALL OF CWA BY 18Z MON. IF ECMWF IS CLOSE TO BEING RIGHT...COULD HAVE NEAR BLIZZARD CONDITIONS MONDAY AFTERNOON ACROSS MUCH OF THE AREA. RAISED POPS TO THE LIKELY CATEGORY FOR SUNDAY NIGHT INTO MONDAY. SHOULD SEE SYSTEM GETTING KICKED OUT BY NEXT SYSTEM ENTERING INTO THE WEST COAST MONDAY NIGHT WITH PRECIP ENDING ACROSS AREA BY TUESDAY MORNING. COULD SEE SEVERAL INCHES OF SNOW ACROSS KS BY TUESDAY MORNING...AND EXPECT TEMPERATURES FOR THE NEXT COUPLE OF DAYS TO BE GREATLY INFLUENCED BY THIS...SO ONLY HAVE HIGHS IN THE LOWER TO MID 30S TUESDAY AND ONLY SLIGHTLY WARMER WEDNESDAY. && .PRELIMINARY POINT TEMPS/POPS... DDC 53 35 45 39 / 10 0 40 40 GCK 53 35 46 39 / 0 0 40 40 EHA 57 36 48 40 / 10 0 30 30 LBL 55 36 47 40 / 10 0 30 30 HYS 47 33 43 36 / 0 20 60 60 P28 52 37 46 40 / 10 30 60 60 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ FN27/28 ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 330 AM EST FRI MAR 17 2006 .SHORT TERM /TODAY/... WEAK LOW PRESSURE CENTERED OVER NORTHEASTERN NC AT 12Z THIS MORNING WILL MOVE RAPIDLY EASTWARD OFF THE COAST BY 15Z. RADAR TRENDS AND 00Z NAM AND 00Z RUC SUPPORT ONLY WEAK ISENTROPIC LIFT ACROSS CENTRAL VA BETWEEN 09Z AND 12Z WITH LIGHT QPF AND WEAKENING BAND OF PRECIPITATION MOVING FROM NORTHERN WV/NORTHWESTERN MD INTO NORTHERN VA AND NORTH CENTRAL MD. THESE TRENDS AND LATEST MODEL INDICATIONS POINT TOWARD MARGINAL SNOW ADVISORY ACCUMULATIONS...WHERE WET BULB EFFECT WILL BE STRONG ENOUGH TO CHANGE RAIN OR MIXTURE OF RAIN/SNOW TO ALL SNOW. 07Z TEMPERATURES IN ALL LOW ELEVATION SITES OF THE CWA IN THE 40S WITH QUITE A FEW OBS IN THE HIGH 40S SUGGEST THAT IT MAY TAKE LONGER TO TRANSITION TO ALL SNOW. WILL REMOVE WASHINGTON AND FREDERICK COUNTIES IN MD...MORGAN...BERKELEY...AND JEFFERSON COUNTIES IN WV...AND FREDERICK...CLARK AND LOUDOUN COUNTIES IN VA FROM THE SNOW ADVISORY...AS BEST POTENTIAL OVERRUNNING HAS SHIFTED SOUTH WITH RECENT MODEL RUNS. HIGH PRESSURE FROM CENTRAL CANADA WILL BUILD SLOWLY SOUTHWARD BEHIND THE DEPARTING LOW PRESSURE SYSTEM LATE THIS MORNING THROUGH THE REST OF THE DAY. WEAK TO MODERATE CAA WILL KEEP TEMPERATURES 4 TO 6 F BELOW NORMAL IN THE MID 40S TO LOWER 50S...DESPITE CLEARING SKIES AND A GOOD DEAL OF SUNSHINE BY LATE AFTERNOON ACROSS THE ENTIRE CWA. && .LONG TERM /TONIGHT THROUGH THURSDAY/... SPRAWLING AREA OF HIPRES NOSES IN FM CNDA TNGT...AND HOLDS THRU WKND. AMS DRY THRUT COLUMN...W/ SFC DEWPTS IN THE TEENS...AND H10-5 RH AOB 30 PCT. JUST ABT THE ONLY CONSIDERATION WL BE THE WND SAT... AS H8-5 LOW WL KEEP A DECENT GRADIENT ACRS AREA. H8 CAA AND SHEARED H5 VORT EMBEDDED IN FLOW WL ASSIST IN MIXING WNDS TO SFC. MOMENTUM TRANSFER SUGGESTING GUSTS 20-30 KT. BY SUN...HIPRES WL BE NEAR ENUF SO THAT WNDS WL BE LGTR. MOS TEMPS NOT FAR APART...AND BLEND GNLY TAKEN. SFC LOPRES DVLPG IN SRN CONUS MON MRNG WL NEED TO BE WATCHED...AS IT TOSSES MSTR TWD CWFA MON AFTN-TUE MRNG. 12Z GFS FASTER AT F84 AND MUCH MORE PROGRESSIVE THRAFTR COMPARED TO NAM. SFC HIGH WL BE ABLE TO WARD OFF INITIAL SURGE...BUT FOR HOW LONG? UNLIKE CRRNT SYSTM... THIS ONE WL HV PLENTY OF MSTR AVBL THX TO GLFMEX AND COOL AIR WL BE IN PLACE...SO PTYPE WL BE AN ISSUE. WL HOLD W/ CRRNT SET OF GRIDS... TACKLING ONE STORM AT A TIME. && .AVIATION... WEAK LOW WILL PASS ACROSS NORTHERN NC THIS MORNING WITH LIGHT PRECIPITATION DEVELOPING AT ALL TAF SITES BETWEEN 08Z AND 10Z...BUT DESPITE PRECIPITATION EXPECT VFR CIGS AND VSBYS TO PREDOMINATE. BEST CHANCE FOR IFR CONDITIONS WILL BE FOR A BRIEF WINDOW FROM 10Z-12Z AT MRB/IAD/DCA/BWI/MTN AND 10Z-13Z AT CHO. LOW WILL MOVE QUICKLY OFF THE NC COAST AFTER 12Z...AND DRIER AIR WILL FILTER INTO THE REGION WITH NORTH WINDS LESS THAN 10 KT THROUGH THE REMAINDER OF THE DAY. VFR CONDITIONS ARE EXPECTED FROM 12Z FRIDAY THROUGH 12Z SATURDAY... EXCEPT AT CHO WHERE VFR WILL BEGIN AT OR ABOUT 13Z. && .MARINE... NLY FLOW AOB 10 KT ACRS WATERS TDA. TNGT...CAA AND PVA WL COMBINE TO PROVIDE BRZY CONDS ACRS THE WATERS...WHERE MIXING SHUD BE GOOD THX TO LAPSE RATES. BASED UPON MOMENTUM TRANSFER FM HRLY SNDGS...CUD SEE SCA TYPE WNDS SAT...FM ELY MRNG THRU EVE. HIPRES BLDG ACRS WATERS WL ENSURE CONDS ARENT PROLONGED BYD THAT. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...SNOW ADVISORY FOR MDZ002 UNTIL 10 AM FRIDAY. VA...SNOW ADVISORY FOR VAZ021-025>027-029-030 UNTIL 10 AM FRIDAY. WV...SNOW ADVISORY FOR WVZ048>050-054-055 UNTIL 10 AM FRIDAY. MARINE...SMALL CRAFT ADVISORY FOR ANZ530>537 FROM 1 AM SATURDAY TO 1 AM SUNDAY. && $$ SHORT TERM/AVIATION...SMITH LONG TERM/MARINE...HTS md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 100 AM EST THU MAR 16 2006 .AVIATION (06Z-06Z)... LOW PRESSURE THAT BROUGHT A FEW THUNDERSTORMS AND MIXED RAIN AND SNOW IS DEPARTING THROUGH EASTERN KENTUCKY. HIGH PRESSURE AND DRIER AIR ARE BUILDING IN. MODEL SOUNDINGS INDICATE RAPID CLEARING...BIT SATELLITE INDICATES OTHERWISE SO WENT WITH MVFR CEILINGS THROUGH ABOUT 18Z. REST OF FORECAST VFR. && .SHORT TERM (REST OF TONIGHT)... RAIN WAS SPREADING ACROSS THE AREA THIS EVENING...WITH ISOLATED THUNDER MOVING INTO EAST CENTRAL INDIANA. HAVE UPDATED FOR THIS IN THE WEST CENTRAL OHIO AND DAYTON ZONE GROUPS. NOT MANY CHANGES TO THE FCST...WILL LIKELY UPDATE AGAIN IN THE NEXT FEW HOURS AS SFC LOW MOVES CLOSER AND PCPN COVERAGE CHANGES. && PREVIOUS DISCUSSION... (ISSUED 245 PM EST THU MAR 16 2006) SHORT TERM (TONIGHT THROUGH SATURDAY NIGHT)... DECENT RETURNS SHOWING UP ON RADAR ACROSS NORTHERN OHIO BUT WITH DRY AIRMASS IN PLACE...IT APPEARS THAT THIS PCPN IS NOT REACHING THE GROUND (NOT SURE IF THE .12 REPORTED ON THE AOH OB THIS PAST HOUR WAS REAL). 12Z MODELS HAVE TRENDED SLIGHTLY FARTHER SOUTH WITH THE TRACK OF THE LOW OVERNIGHT TONIGHT...SPREADING PCPN DOWN ACROSS AREA THROUGH THIS EVENING. HOWEVER...AM CONCERNED ABOUT LARGE DRY SLOT ACROSS SOUTHERN ILLINOIS AND LATEST RUC SEEMS TO BE PICKING UP ON THIS...KEEPING MUCH OF SOUTHWEST FA MAINLY DRY TONIGHT. ISENTROPIC LIFT IS FORECAST TO INCREASE ON THE 290K-295 K SURFACES BETWEEN NOW AND 03Z AS SURFACE LOW MOVES FROM CENTRAL ILLINOIS INTO SOUTHERN INDIANA. AS A RESULT...EXPECT TO SEE PCPN BEGIN TO FILL IN A LITTLE FARTHER SOUTH THAN WHERE THINGS ARE CURRENTLY SHOWING UP ON RADAR. WITH THIS IN MIND...WILL STILL ALLOW FOR PCPN TO DEVELOP DOWN INTO FA THROUGH THIS EVENING...BUT WE COULD END UP WITH A FAIRLY SHARP SOUTHERN EDGE. WILL THEREFORE...ONLY GO WITH CHANCE POPS ACROSS THE SOUTHWEST. MODELS FAIRLY CONSISTENT SHOWING BOUNDARY LAYER COOLING OFF FROM NORTH TO SOUTH ACROSS THE AREA OVERNIGHT. BASED ON BLEND OF FORECAST SOUNDINGS FROM THE GFS AND NAM...EXPECT PCPN TO MIX WITH AND THEN CHANGE OVER TO SNOW ACROSS THE FAR NORTH LATE THIS EVENING AND THEN ACROSS CENTRAL PORTIONS OF FA AFTER MIDNIGHT. ACROSS THE FAR SOUTH...ANY CHANGEOVER WOULD BE LATE TONIGHT OR FRIDAY MORNING. SNOWFALL ACCUMULATIONS ARE PROBLEMATIC AS DRY AIR IN PLACE AND RELATIVELY WARM GROUND TEMPERATURES WILL LIKELY CUT BACK ON ANY ACCUMULATIONS. HOWEVER...THIS WILL BE COUNTERED BY THE FACT THAT THE SNOW WILL BE FALLING DURING THE NIGHTTIME PERIOD AND POSSIBILITY FOR SOME CONVECTIVE ENHANCEMENT. ACROSS THE FAR NORTH...WHERE CHANGEOVER SHOULD OCCUR THE EARLIEST...WILL GO WITH 1 TO 2 INCHES WITH UP TO AN INCH DOWN TO ABOUT I-70. FARTHER TO THE SOUTH...CHANGE OVER SHOULD BE LATE ENOUGH TO LIMIT ANY ACCUMULATIONS. WILL HANG ON TO SOME LOWER CLOUDS THROUGH THE MORNING ON FRIDAY WITH LINGERING LOWER LEVEL MOISTURE AND CAA. WILL ALSO UNDERCUT GUIDANCE TEMPS A FEW DEGREES FOR HIGHS FRIDAY. OTHERWISE...HIGH PRESSURE THEN BUILDS IN THROUGH THE REMAINDER OF THE SHORT TERM FOR QUIET WEATHER INTO THE WEEKEND. LONG TERM (SUNDAY THROUGH THURSDAY)... MODELS HAVE TRENDED STRONGER AND SLOWER WITH THE STORM SYSTEM EARLY NEXT WEEK. THIS SUPPORTS YESTERDAYS 12Z RUN WHICH WAS SLOWER WITH THE ONSET OF PCPN. THEREFORE DELAYED THE ONSET OF PCPN UNTIL MONDAY NIGHT. GFS HAS BEEN TRENDING FARTHER SOUTH WITH THE LOW. 06Z RUN HAS THE LOW IN CNTRL KY AT 12Z TUE...12Z GFS NOW HAS IT IN ERN TN. WENT A BLEND OF 06Z/12Z GFS RUNS...SO WAS COOLER THAN THE 00Z MEX FOR HIGHS TUE. THE BLEND OF THE THICKNESSES PUTS THE RAIN/SNOW LINE AROUND THE OHIO RIVER FOR TUE...BUT THEREFORE SHOULD BE A CHANGE OVER TO ALL SNOW ON THE BACKEDGE. LOW PULLS OF THE EAST COAST TUESDAY NIGHT. WITH COLD NW FLOW...MODELS ARE SUGGESTING THAT THERE MIGHT BE SOME LAKE EFFECT SHOWERS WED AND THU. OTHER THAN BEING COOLER WITH TUE MAXS...WENT CLOSE TO MEX NUMBERS. SITES && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SHORT TERM... oh AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 348 AM CST FRI MAR 17 2006 .DISCUSSION... UPDATE...DECIDED TO GO WITH AN NPW FOR DENSE FOG FOR THE COASTAL COUNTIES. VSBYS DOWN TO 1/4 MILE AT SEVERAL SITES. FOG SHOULD ERODE BETWEEN 14-15Z WITH THE FRONTAL PASSAGE. AT 08Z...A VERY SLOW MOVING COOL FRONT EXTENDED ACROSS EAST TEXAS FROM JASPER TO CALDWELL TO JUNCTION. THIS BOUNDARY IS STILL EXPECTED TO CROSS THE REGION BEFORE STALLING JUST SOUTH OF THE COUNTY WARNING AREA. TEMPERATURES ARE STILL QUITE WARM AND ALTHOUGH NOT MUCH OF A TEMPERATURE RISE IS EXPECTED TODAY...STILL FEEL THE WARM START WILL ALLOW TEMPS TO BE HIGHER THAN GUIDANCE. DENSE FOG HAS DEVELOPED IN A FEW SPOTS AHEAD OF THE BOUNDARY. WILL MENTION PATCHY DENSE FOG THROUGH 14Z FOR THE COASTAL COUNTIES. THE FRONT WILL RETURN NORTH ON SATURDAY AND THIS BOUNDARY WILL SERVE AS A FOCUS FOR SCATTERED SHOWERS. TEMPS MAY ACTUALLY RISE SATURDAY NIGHT OVER THE NORTH. EARLIER IN THE WEEK...IT LOOKED LIKE SE TX WOULD RECEIVE SOME GENEROUS RAINFALL OVER THE WEEKEND. AT THIS TIME...SIGNIFICANT RAIN LOOKS LESS LIKELY. ISENTROPIC UPLIFT FAVORS THE EXTREME NORTHERN PART OF SE TX SATURDAY NIGHT AND SUNDAY. HAVE RAISED POPS OVER THE NORTH. THE LACK OF ANY LOW LEVEL CONVERGENCE/UPPER LEVEL SUPPORT WILL LIMIT RAIN CHANCES OVER THE SOUTH. SUNDAY WILL BE WARMER AS SOUTH WINDS PREVAIL AREAWIDE AND BREAKS IN THE CLOUD COVER OVER THE SOUTH OFFER ADDITIONAL INSOLATION. THINGS GET VERY INTERESTING SUNDAY NIGHT. AN UPPER LEVEL STORM SYSTEM WILL MOVE EAST TAKING ON A NEGATIVE TILT. THE LOW LEVEL JET WILL STRENGTHEN AND A 110 KT SPEED MAX WILL APPROACH THE AREA. THE JET WILL SPLIT OVER THE AREA. AT THE SURFACE A PACIFIC FRONT/DRY LINE WILL APPROACH CLL AROUND 08Z AND THE COAST AROUND 12Z. THIS WILL PROVIDE THE LOW LEVEL FOCUS TO INITIATE THUNDERSTORMS. LAPSE RATES ARE FORECAST TO INCREASE TO AROUND 8.0...CAPES BETWEEN 2000-3000...HELICITIES BETWEEN 200 AND 400 AND LI'S BETWEEN -4 AND -8. ALL THE PARAMETERS SEEM TO BE IN PLACE FOR WIDESPREAD SEVERE WEATHER LATE SUNDAY NIGHT. THE SYSTEM WILL MOVE QUICKLY THUS LIMITING RAINFALL POTENTIAL. ONE CAVEAT... CAPPING INVERSION OVER THE SOUTH MUST ERODE. CURRENT THINKING IS THAT THE CAP WILL ERODE. DEW POINTS WILL DROP QUICKLY IN THE WAKE OF THE DRY LINE/FRONT AND WINDS JUST ABOVE THE SURFACE WILL BE FROM THE WEST. AS A CONSEQUENCE...TEMPS ON MONDAY WILL BE WARM. TUES/WED LOOK DRY. A DECENT DIURNAL RANGE BOTH DAYS DUE TO THE DRY AIR MASS. ANOTHER SHORT WAVE WILL MOVE EAST ACROSS THE SOUTHERN PLAINS WEDNESDAY NIGHT WITH AN INVERTED TROUGH DEVELOPING ALONG THE LOWER TEXAS COAST. WILL MENTION A SLIGHT CHANCE OF RAIN WED NIGHT/THU MORNING. 43 && .AVIATION... LIFR CONDITIONS WILL EXIST EARLY THIS MORNING ALONG THE IMMEDIATE COAST AND AFFECT BOTH GLS AND LBX THROUGH SUNRISE. THE VERY SLOW MOVING FRONT AND ITS ASSOCIATED PREFRONTAL TROUGH WERE THE CULPRITS. THE LATEST RUC HANGS THE FRONT UP A BIT EARLY...BUT THEN MOVES IT THROUGH TO THE COAST BETWEEN 15Z AND 18Z. THE ETA12 IS A BIT FASTER WHILE THE GFS IS A BIT MORE COMPLICATED. CAN EXPECT VFR CEILINGS ABOVE 4000 FEET AT THE REMAINDER OF THE SITES. HOWEVER...IF THE FRONT WAFFLES A BIT NORTHWARD THEN IFR CONDITIONS FOR FOG AND LOW STRATUS MAY OCCUR AT HOU AND EVEN IAH FOR A BIT THROUGH 13 OR 15Z. THE NEXT PROBLEM OF THE DAY IS WINDS. NORTHEASTERLY WINDS THIS AFTERNOON WILL PICK UP A BIT TOWARD THE 15 KNOT RANGE AS THE FRONT MOVES THROUGH. PL-40 && .MARINE... SCEC CONDITIONS ARE EXPECTED THIS AFTERNOON. THE MODELS WERE A BIT WEAKER WITH THE SURFACE WINDS THAN WHAT WAS PRESENT IN THE EARLIER PACKAGES. PL-40 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 68 58 65 65 75 / 10 40 50 60 60 HOUSTON (IAH) 73 59 70 68 78 / 20 30 40 40 30 GALVESTON (GLS) 71 64 70 70 73 / 20 30 50 50 20 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT SHOULD EXERCISE CAUTION FROM NOON FRIDAY TO 6 PM FRIDAY FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...AND WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM. && $$ tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 342 AM CST FRI MAR 17 2006 .DISCUSSION... AT 08Z...A VERY SLOW MOVING COOL FRONT EXTENDED ACROSS EAST TEXAS FROM JASPER TO CALDWELL TO JUNCTION. THIS BOUNDARY IS STILL EXPECTED TO CROSS THE REGION BEFORE STALLING JUST SOUTH OF THE COUNTY WARNING AREA. TEMPERATURES ARE STILL QUITE WARM AND ALTHOUGH NOT MUCH OF A TEMPERATURE RISE IS EXPECTED TODAY...STILL FEEL THE WARM START WILL ALLOW TEMPS TO BE HIGHER THAN GUIDANCE. DENSE FOG HAS DEVELOPED IN A FEW SPOTS AHEAD OF THE BOUNDARY. WILL MENTION PATCHY DENSE FOG THROUGH 14Z FOR THE COASTAL COUNTIES. THE FRONT WILL RETURN NORTH ON SATURDAY AND THIS BOUNDARY WILL SERVE AS A FOCUS FOR SCATTERED SHOWERS. TEMPS MAY ACTUALLY RISE SATURDAY NIGHT OVER THE NORTH. EARLIER IN THE WEEK...IT LOOKED LIKE SE TX WOULD RECEIVE SOME GENEROUS RAINFALL OVER THE WEEKEND. AT THIS TIME...SIGNIFICANT RAIN LOOKS LESS LIKELY. ISENTROPIC UPLIFT FAVORS THE EXTREME NORTHERN PART OF SE TX SATURDAY NIGHT AND SUNDAY. HAVE RAISED POPS OVER THE NORTH. THE LACK OF ANY LOW LEVEL CONVERGENCE/UPPER LEVEL SUPPORT WILL LIMIT RAIN CHANCES OVER THE SOUTH. SUNDAY WILL BE WARMER AS SOUTH WINDS PREVAIL AREAWIDE AND BREAKS IN THE CLOUD COVER OVER THE SOUTH OFFER ADDITIONAL INSOLATION. THINGS GET VERY INTERESTING SUNDAY NIGHT. AN UPPER LEVEL STORM SYSTEM WILL MOVE EAST TAKING ON A NEGATIVE TILT. THE LOW LEVEL JET WILL STRENGTHEN AND A 110 KT SPEED MAX WILL APPROACH THE AREA. THE JET WILL SPLIT OVER THE AREA. AT THE SURFACE A PACIFIC FRONT/DRY LINE WILL APPROACH CLL AROUND 08Z AND THE COAST AROUND 12Z. THIS WILL PROVIDE THE LOW LEVEL FOCUS TO INITIATE THUNDERSTORMS. LAPSE RATES ARE FORECAST TO INCREASE TO AROUND 8.0...CAPES BETWEEN 2000-3000...HELICITIES BETWEEN 200 AND 400 AND LI'S BETWEEN -4 AND -8. ALL THE PARAMETERS SEEM TO BE IN PLACE FOR WIDESPREAD SEVERE WEATHER LATE SUNDAY NIGHT. THE SYSTEM WILL MOVE QUICKLY THUS LIMITING RAINFALL POTENTIAL. ONE CAVEAT... CAPPING INVERSION OVER THE SOUTH MUST ERODE. CURRENT THINKING IS THAT THE CAP WILL ERODE. DEW POINTS WILL DROP QUICKLY IN THE WAKE OF THE DRY LINE/FRONT AND WINDS JUST ABOVE THE SURFACE WILL BE FROM THE WEST. AS A CONSEQUENCE...TEMPS ON MONDAY WILL BE WARM. TUES/WED LOOK DRY. A DECENT DIURNAL RANGE BOTH DAYS DUE TO THE DRY AIR MASS. ANOTHER SHORT WAVE WILL MOVE EAST ACROSS THE SOUTHERN PLAINS WEDNESDAY NIGHT WITH AN INVERTED TROUGH DEVELOPING ALONG THE LOWER TEXAS COAST. WILL MENTION A SLIGHT CHANCE OF RAIN WED NIGHT/THU MORNING. 43 && .AVIATION... LIFR CONDITIONS WILL EXIST EARLY THIS MORNING ALONG THE IMMEDIATE COAST AND AFFECT BOTH GLS AND LBX THROUGH SUNRISE. THE VERY SLOW MOVING FRONT AND ITS ASSOCIATED PREFRONTAL TROUGH WERE THE CULPRITS. THE LATEST RUC HANGS THE FRONT UP A BIT EARLY...BUT THEN MOVES IT THROUGH TO THE COAST BETWEEN 15Z AND 18Z. THE ETA12 IS A BIT FASTER WHILE THE GFS IS A BIT MORE COMPLICATED. CAN EXPECT VFR CEILINGS ABOVE 4000 FEET AT THE REMAINDER OF THE SITES. HOWEVER...IF THE FRONT WAFFLES A BIT NORTHWARD THEN IFR CONDITIONS FOR FOG AND LOW STRATUS MAY OCCUR AT HOU AND EVEN IAH FOR A BIT THROUGH 13 OR 15Z. THE NEXT PROBLEM OF THE DAY IS WINDS. NORTHEASTERLY WINDS THIS AFTERNOON WILL PICK UP A BIT TOWARD THE 15 KNOT RANGE AS THE FRONT MOVES THROUGH. PL-40 && .MARINE... SCEC CONDITIONS ARE EXPECTED THIS AFTERNOON. THE MODELS WERE A BIT WEAKER WITH THE SURFACE WINDS THAN WHAT WAS PRESENT IN THE EARLIER PACKAGES. PL-40 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 68 58 65 65 75 / 10 40 50 60 60 HOUSTON (IAH) 73 59 70 68 78 / 20 30 40 40 30 GALVESTON (GLS) 71 64 70 70 73 / 20 30 50 50 20 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT SHOULD EXERCISE CAUTION FROM NOON FRIDAY TO 6 PM FRIDAY FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...AND WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM. && $$ tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 1140 PM CST THU MAR 16 2006 .AVIATION... FRONT RETURNING AS WARM FRONT...JUST NORTH OF DEL RIO... KERRVILLE... AUSTIN LINE AT 5Z. MID LEVEL CLOUDS AND MOISTURE INSTABILITY AROUND 6000 AGL WAS DEVELOPING ALONG THE FRONT AND SLOWLY EXPANDING NORTH. MAY SEE SOME ISOLATED SHOWERS AND THUNDERSTORMS NEAR KSJT TONIGHT...BUT LEFT OUT OF TAF DUE TO LOW PROBABILITY. NAM AND GFS MODELS CONTINUE TO BRING MID LEVEL MOISTURE AND CLOUDS OVER THE REGION FRIDAY...BUT KEEP LOW LEVELS DRY UNTIL AFTER 00Z WHEN LOW LEVELS GRADUALLY SATURATE AND CIGS LOWER TO MVFR. MAY TAKE UNTIL AFTER TAF PERIOD OF 6Z FOR CIGS TO LOWER INTO MVFR CATEGORY FOR KABI. POTENTIAL FOR SCATTERED THUNDERSTORMS THIS AFTERNOON WITH THUNDERSTORMS LIKELY AFTER 00Z AS AN UPPER LEVEL SHORT WAVE MOVES ACROSS. BECAUSE LOW LEVELS ARE DRY...COULD SEE SOME VERY GUSTY WINDS IN VICINITY OF ANY STORMS LATE AFTERNOON AND EVENING. && .PREV DISCUSSION... (ISSUED 805 PM CST THU MAR 16 2006) UPDATE...WILL BE UPDATING TO RAISE POPS OVERNIGHT. FRONT HAS PUSHED TO THE SOUTH OF I-10 THIS EVENING. ABOVE THE SURFACE FRONT...AREA OF ACCAS DEVELOPED ALONG THE 850 MB FRONT. TCU DEVELOPED RIGHT AT SUNSET ALONG THIS MID LEVEL BOUNDARY AND RADAR ECHOES WERE NOTED. THESE HAVE SINCE DISSIPATED...BUT IS A GOOD INDICATION OF THE GOOD INSTABILITY DERIVED FROM THE ELEVATED PARCELS. MUCAPES FROM THE RUC CURRENTLY RUNNING AROUND 1500 J/KG ALONG THE BOUNDARY. THIS AREA IS FORECAST TO LIFT NORTHWEST OVERNIGHT AND INTENSIFYING LOW LEVEL JET WILL HELP TO ISENTROPICALLY LIFT PARCELS ABOVE THE STABLE BOUNDARY LAYER. RAINFALL AMOUNTS SHOULD BE LIGHT TONIGHT WITH THE DRY SUB-CLOUD LAYER...HOWEVER ELEVATED CONVECTION COULD BECOME STRONG WITH MARGINALLY SEVERE HAIL AND EVENTUALLY HEAVIER RAINS IN THE MOST INTENSE CONVECTION. AT THIS TIME TEMPERATURES LOOK OKAY AND WILL ONLY BE TWEAKING THE POPS AT THIS TIME. BRAZZELL PREV DISCUSSION... (ISSUED 520 PM CST THU MAR 16 2006) AVIATION... EXPECT VFR CONDITIONS TO CONTINUE OVER THE NEXT 24 HOURS. AT TERMINAL KABI THE NORTHERLY WINDS WILL SLOWLY SHIFT TO THE EAST/NORTHEAST THIS EVENING. AT BOTH KABI AND KSJT WINDS WILL REMAIN AT OR BELOW 10 KTS OVERNIGHT. AFTER 11Z/17 WINDS WILL INCREASE TO AROUND 15 KTS. PREV DISCUSSION... (ISSUED 317 PM CST THU MAR 16 2006) SHORT TERM... FRONTAL BOUNDARY HAS PROGRESSED SOUTH TO THE INTERSTATE 10 CORRIDOR THIS AFTERNOON WITH DEWPOINTS IN THE TEENS FROM THE CENTRAL CWA NORTH ABOUT TEN DEGREES COOLER THAN THE LATEST GFS. THE FRONT SHOULD STALL SOMEWHERE SOUTH OF INTERSTATE 10 THIS EVENING WITH A SLIGHT CHANCE OF SHOWERS ALONG THE BOUNDARY. BOUNDARY SHOULD REMAIN ALONG SOUTHERN PERIFERY OF THE CWA INTO FRIDAY AS AN UPPER TROUGH AXIS DIGS SOUTH ALONG THE PACIFIC COAST. AS DISTURBANCES TRACK NORTHEAST OVER CENTRAL TEXAS AHEAD OF THE UPPER LEVEL TROUGH AND A DEVELOPING LLJ PUSHES GULF MOISTURE OVER THE BOUNDARY...WILL SEE AN INCREASING POSSIBILITY OF SHOWERS AND THUNDERSTORMS DEVELOPING INTO FRIDAY EVENING AND OVERNIGHT FRIDAY. LONG TERM... FRONTAL BOUNDARY WILL BEGIN EDGING NORTHWARD AHEAD OF THE APPROACHING UPPER LEVEL TROUGH WITH THE BEST CHANCE OF RAINFALL OVER THE NORTHERN CWA INTO THIS WEEKEND. DRYLINE WILL REMAIN WEST OF THE CWA UNTIL LATE SUNDAY WHEN IT WILL BE PUSHED EAST BY THE APPROACHING STORM SYSTEM. TIMING WILL BE CRITICAL AS TO EXTENT AND SEVERITY OF ANY ASSOCIATED STORMS ON SUNDAY. IT APPEARS NOW THAT DRYLINE PASSAGE WILL BE LATE SUNDAY INTO MONDAY MORNING WITH THE BEST CHANCE OF THUNDERSTORMS DEVELOPING ALONG AND EAST OF THE DRYLINE/FRONT OVER THE BIG COUNTRY AREA AND MOVING VERY QUICKLY TO THE NORTHEAST. THE ASSOCIATED TRIPLE POINT IS PROGD TO BE OVER SOUTHEAST OKLAHOMA BY EARLY MONDAY MORNING WITH RAPID DRYING FROM WEST TO EAST OVER THE CWA. THE PREVIOUS GFS HAD AN UPPER LOW TRACKING INTO CENTRAL TEXAS ON FRIDAY...LATEST RUN HAS AN UPPER RIDGE OVER THE CENTRAL STATES WITH A DEVELOPING TROUGH ALONG THE PACIFIC...WILL LEAVE THE EXTENDED DRY. SJT WATCHES/WARNINGS/ADVISORIES... NONE. $$ SJT WATCHES/WARNINGS/ADVISORIES... NONE. $$ && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 04/99/04 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 1010 AM EST FRI MAR 17 2006 .DISCUSSION... THE 13 UTC SURFACE ANALYSIS SHOWS A COLD FRONT FROM ATLANTA GA TO LAKE CHARLES LA...APPROACHING THE NORTHWEST PORTIONS OF OUR FORECAST AREA. A FEW SPRINKLES ARE MOVING QUICKLY TOWARD THE SOUTHEAST ACROSS OUR FLORIDA ZONES...AS IS A FRONTAL CLOUD BAND. VAPOR IMAGERY AND UPPER AIR OBSERVATIONS SHOW THE SHORT WAVE TROUGH AXIS HAS PASSED US BY AND WE ARE NOW UNDER NORTHWEST FLOW ALOFT. THE SHALLOW LOW CLOUDS HAVE GENERALLY BEEN DECREASING...AND WE SUSPECT THAT WITH THE DELAY OF THE FRONTAL PASSAGE TILL LATER THIS AFTERNOON AND THE INCREASING INSOLATION OUR TEMPERATURES WILL BE A LITTLE WARMER THAN THE PREVIOUS FORECAST. THE MAIN FORECAST CHALLENGE TODAY WILL BE THE RELATIVE HUMIDITY. THE LATEST RUC HAS A VERY GOOD HANDLE OF THE SURFACE DEWPOINT TROUGH OVER OUR AREA...AND THIS WAS THE SAME AREA THAT REALLY DRIED OUT THURSDAY AFTERNOON AS INTENSE MIXING DEVELOPED. WE USED THE RUC DEWPOINT FORECAST...AND WITH THE SLIGHTLY WARMER TEMPERATURES WE ARE NOW FORECASTING ABOUT 4 HOURS OF RELATIVE HUMIDITY BELOW 35 PERCENT ACROSS PORTIONS OF OUR FLORIDA ZONES. IF WE SEE A DRAMATIC DECLINE IN DEWPOINTS EARLY THIS AFTERNOON WE MAY HAVE TO ISSUE A RED FLAG WARNING. OTHERWISE NO MAJOR CHANGES WERE MADE TO THE MORNING FORECAST PACKAGE. && .AVIATION... VFR CONDITIONS WILL PREVAIL AT OUR NORTHWESTERN TERMINALS (DHN ABY AND PFN) SHORTLY AS CLEARING SKIES ARE ON THE HORIZON. MVFR CONDITIONS WILL CONTINUE AT TLH AND VLD UNTIL THE FRONT PASSES THERE LATER THIS AFTERNOON. THE FRONT SHOULD PASS TLH AND VLD AROUND 17Z. ONCE THE FRONT CLEARS THE AREA...VFR CONDITIONS WILL PREVAIL THROUGH THE AFTERNOON AND OVERNIGHT HOURS. .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...RED FLAG WARNING SATURDAY NOON-7 PM ALL AREAS. && $$ AVIATION...GODSEY REST OF DISCUSSION...FOURNIER fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSONVILLE FL 950 AM EST FRI MAR 17 2006 DRY COLD FRONT OVER CENTRAL GA PUSHING SE ACOMMPANIED BY SCATTERED CLOUDS. FRONT SHOULD PUSH THROUGH THE AREA THIS AFTERNOON AND EARLY EVENING SHIFTING WEST WINDS TO NW. WARM AND BREEZY CONDITIONS WILL LIFT TEMPERATURES TO AROUND 80. .MARINE...WESTERLY WINDS 10 TO 15 KNOTS TODAY WITH SEAS 2 TO 3 FEET. LIGHT CHOP OVER INLAND WATERS MAY BECOME BRIEFLY BECOME A MODERATE CHOP AS WINDS INCREASE THIS AFTERNOON. .FIRE...WILL LIKELY SEE MARGINAL RED FLAG CONDITIONS OVER NE FL THIS AFTERNOON. MARGINAL RH DURATION AND/OR WIND CRITERIA BOTH POSSIBLE. 12Z JAX SOUNDING SHOWED DRY AIR IN 950 TO 850MB LAYER AND JAX SURFACE DEWPOINT HAS NOW FALLEN TO 45 AS VERTICAL MIXING COMMENCES. WILL ISSUE RED FLAG WARNING FOR NE FL THIS AFTERNOON. && MZ/JH ......PREVIOUS DISCUSSION...... .SHORT TERM...RUC ANALYSIS SHOWS SHORT WAVE TROUGH ALIGNED WEST TO EAST AND ROUGHLY ALONG THE GEORGIA/FLORIDA STATE LINE. EXTENSIVE CLOUD DECK EXISTS FROM NORTH GEORGIA THROUGH THE NORTHERN SECTIONS OF THE FORECAST AREA. MOISTURE BELOW 800 MB IN THESE AREAS IS VERY LOW WITH DEW POINT DEPRESSIONS GREATER THAN 25 DEGREES JUST OFF THE SURFACE. THIS LEADS TO GREATER CONFIDENCE THAT SHORT TERM GRIDS ARE ON TRACK FOR SILENT POPS. THERE IS SOME SLIGHTLY MOISTER AIR OVER SOUTHERN SECTIONS OF THE CWA AND AS SHORTWAVE SINKS SOUTHWARD...A FEW SPRINKLES WILL BE POSSIBLE OVER THESE AREAS. ALTHOUGH THE FLOW ALOFT WILL BECOME NORTHWEST BY EARLY AFTERNOON...SURFACE FLOW WILL REMAIN WESTERLY IN THE WAKE OF SURFACE LOW OFF THE CAROLINA COAST. THIS WILL RESULT IN A CONTINUATION OF WARM TEMPERATURES AREA WIDE WITH SOUTHERN SECTIONS NEARING THE 80 DEGREE MARK. COLD AIR ADVECTION COMMENCES OVER THE GEORGIA PORTION AROUND 06Z TONIGHT WHILE THE FLORIDA PORTION IS DELAYED LARGELY UNTIL SATURDAY. THIS WILL RESULT IN COOLER TEMPS OVER THE GEORGIA PORTION FRIDAY NIGHT BUT SIMILAR VALUES TO TONIGHTS OVER THE FLORIDA PORTION. VERY QUICK SHOT OF COOLER AIR WILL BRING MAX TEMPS FOR SAT TO BELOW NORMAL FOR ALL AREAS...ESPECIALLY ALONG THE COAST WHERE NORTHEAST FLOW WILL KEEP TEMPS DOWN. NEARLY IDEAL ISENTROPIC LIFT CONDITIONS TO SET UP OVER THE CENTRAL PLAINS AS STRONG HIGH PRESSURE RIDGES DOWN THE CENTRAL SECTIONS OF THE COUNTRY WHILE BROAD SOUTHWEST FLOW ALOFT RIDES UP AND OVER COLD DOME. WITH TIME...THIS HIGH PRESSURE RIDGE WILL BUILD SOUTHEAST...BUT INITIALLY FLOW ALOFT REMAINS NORTHWEST. GRADUALLY FLOW BELOW 500MB BECOMES MORE WESTERLY...AND CROSS SECTIONS INDICATE MODEST CROSS ISOTHERMAL FLOW. GFS IS MUCH MORE AGGRESSIVE WITH THIS FEATURE WITH 5 UNITS OF ADIABATIC OMEGA ALONG AND NORTH OF THE GEORGIA PORTION OF THE FORECAST AREA. WITH AXIS LARGELY NORTH OF THE AREA HOWEVER...WILL BLEND HIGHER MAV NUMBERS WITH THE MET TO RESULT IN LOW END SCATTERED POPS FOR GEORGIA. MY LAST POP GRID OF THE SHORT TERM MATCHES UP VERY WELL WITH INITIAL LONG TERM GRID CREATED BY PREVIOUS FORECASTER. WILL THEREFORE LEAVE MONDAY POPS AS THEY ARE FOR POSSIBLE MODIFICATION BY DAY SHIFT. .LONG TERM...STRONG LOW PRESSURE DEVELOPS OVER ARKANSAS ON MONDAY WITH WARM FRONT WELL NORTH OF THE AREA. COLD FRONT TO PUSH THROUGH ON TUESDAY WITH DRIER CONDITIONS EXPECTED THROUGH MID- WEEK. HAVE INCREASED MAX TEMPS TO BE IN LINE WITH NEWEST MEX IN WARM SECTOR MONDAY BUT NO OTHER CHANGES WILL BE MADE. && .MARINE...NE WINDS INCREASE SAT. STILL LOOKS CLOSE FOR SMALL CRAFT ADVISORY CONDITIONS AND WILL ERR ON THE SIDE OF CAUTION AND HOIST AN ADVISORY FOR THE GA OFFSHORE ZONES. ADVISORY CONDITIONS SHOULD BE SHORT-LIVED...WITH A RETURN EXPECTED BY TUE. && .FIRE WEATHER...VERY TRICKY FCST FOR TODAY. BOTH GFS AND NAM MOS A BIT HIGHER WITH DEW POINT VALUES TODAY. AS A RESULT...ONLY GET RH VALUES INTO THE UPPER 30S. HOWEVER...ONLY NEED ONE OB WITH 35 PERCENT TO COINCIDE WITH SUSTAINED WIND OF 15 MPH. CONCERN IS THAT MID-AFTN WIND SURGE ALONG WITH INCREASED DRY AIR ADVECTION WILL BRING A BRIEF PERIOD OF RED FLAG CONDITIONS FOR EXTREME N FL ZONES. HOWEVER...BASED ON MY LATEST GRIDS...CAN'T JUSTIFY A WARNING AND WILL CANCEL THE WATCH. POTENTIAL FOR A BUST IS THERE...AND DAY SHIFT MAY HAVE TO CHANGE COURSE. WILL INDICATE UNCERTAINTY IN FWF. WILL ISSUE A FIRE WX WATCH FOR W FL ZONES FOR SAT AFTN. THANX FOR COORD TAE/TBW/MLB! && .PRELIMINARY POINT TEMPS/POPS... AMG 77 48 69 46 / 0 0 0 10 SSI 77 51 66 49 / 0 0 0 10 JAX 79 53 68 49 / 0 0 0 0 SGJ 78 56 68 53 / 0 5 0 0 GNV 80 51 75 49 / 5 0 0 0 OCF 80 52 77 51 / 10 0 0 0 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...FIRE WEATHER WATCH FROM NOON TO 5 PM SAT FOR THE FOLLOWING ZONES: ALACHUA...COLUMBIA...GILCHRIST...HAMILTON...MARION... AND SUWANNEE. RED FLAG WARNING FROM NOON TO 5 PM TODAY FOR THE FOLLOWING COUNTIES: HAMILTON-SUWANNEE-COLUMBIA-BAKER-NASSAU-DUVAL- UNION-BRADFORD-CLAY-GILCHRIST-ALACHUA-PUTNAM-MARION- ST JOHNS-FLAGLER- GA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 10 AM TO 4 PM SAT FOR THE FOLLOWING ZONES: ALTAMAHA SOUND TO FERNANDINA BEACH 20 TO 60 NM OFFSHORE. && $$ fl AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PEACHTREE CITY GA 515 AM EST FRI MAR 17 2006 .SHORT TERM...(TODAY THROUGH SUNDAY) BROAD POOL OF MOISTURE STREAMING NORTH AHEAD OF APPROACHING FRONT THIS MORNING COULD LEAD TO LOW CLOUDS THIS MORNING. GFS TRYING TO SQUEEZE OUT SOME LIGHT SHOWERS...BUT NAM SUGGESTS SUBSIDENCE ASSOCIATED WITH DEPARTING JET MAX LEFT REAR QUAD WILL SUPPRESS ANY PRECIP CHANCES. WILL KEEP POPS NIL...BUT WILL RAISE DEWPOINTS AHEAD OF FRONT AS IT APPROACHES. BY 18Z...FRONT WILL BE ACROSS CENTRAL GA AND SKIES/DEWPOINTS BEHIND IT WILL BE MORE IN LINE WITH GUIDANCE. AFTER FRONT PASSES...WIND GUSTS MAY KICK UP TO 15 KTS. OTHERWISE...CONDITIONS WILL REMAIN MILD FOR THE SHORT TERM. CLOUDS WILL INCREASE SATURDAY NIGHT INTO SUNDAY AS NEW SYSTEM FORMS. .LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY) CONDITIONS WILL STEADILY DEGRADE SUNDAY INTO MONDAY...ALTHO GFS/ECMWF/UKMET A BIT FASTER WITH ONSET OF PRECIP THAN NAM. WILL LEAN TOWARD GFS FOR PRECIP ONSET. DEEP LOW DEVELOPS IN CENTRAL PLAINS MONDAY AND BEGINS TO EJECT NORTHEAST OF GA. FRONT WILL FORM SOUTH OF GA AND GRADUALLY LIFT NORTH MONDAY. AHEAD OF FRONT...PRECIP AMOUNTS UP TO AN INCH WILL BE COMMON AS OVERRUNNING SETS UP FOR A BRIEF PERIOD. GFS PULLS WARM FRONT NORTH ON MONDAY PUTTING MOST OF GA IN WARM SECTOR AS COLD FRONT APPROACHES AND PASSES MONDAY NIGHT. SHOULD SEE SUFFICIENT INSTABILITY FOR TSRA NEARLY AREAWIDE. STOUT IN SITU WEDGE FORMS IN NORTHEAST GA MONDAY SO WILL KEEP TEMPS BELOW GUIDANCE THERE. ANOTHER MINOR IMPULSE SKIRTS THE GULF COAST THURSDAY AND RAISES POP CHANCES SLIGHTLY. OTHERWISE...LOOKING COOL AND DRY AS MODIFIED CONTINENTAL POLAR AIRMASS SETTLES IN. && .AVIATION... WNW FLOW ALOFT PREVAILS THROUGH THE SHORT TERM WITH UPSTREAM RIDGE CENTRAL U.S. AND PERSISTENT POLAR VORTEX CANADIAN MARITIMES. WEAK FRONT WILL PASS THROUGH THE AREA THIS MORNING IN ASSOCIATION WITH FAST MOVING UPPER SHORT WAVE. BRIEF PERIOD OF MVFR CIGS THROUGH EARLY MORNING...AROUND 14Z...UNTIL DRIER AIR WORKS INTO THE AREA FROM THE NW...THEN EXPECT MOSTLY VFR CONDITIONS THROUGH TAF VALID PERIOD. AVIATION CONDITIONS WILL DETERIORATE CONSIDERABLY IN THE SUN-MON PERIOD AS COLD WEDGE EVOLVES FROM THE NE AND OVERRUNNING WITH UPSTREAM STRONG SHORT WAVE AND UPPER LOW MOVES OUT OF THE SOUTHERN PLAINS MON. CEILINGS... MOISTURE ADVECTION AHEAD OF FRONT HAS RESULTED IN WIDESPREAD BKN-OVC CIGS OF 015-025...MOSTLY WESTERN SECTIONS. UPSLOPE HAS ENHANCED CLOUD COVER ALONG WESTERN BORDER AND INTO AL...WITH DOWNSLOPE HELPING TO ERODE CLOUDS ON THE EASTERN EDGE. RUC/NAM MODELS SHOW THAT THIS LOW-LEVEL MOISTURE WILL GRADUALLY ERODE IN THE 14-16Z PERIOD FROM THE EAST. EXPECT CONDITIONS TO BECOME SCT 14Z-16Z ACROSS THE WEST. EASTERN SECTIONS LITTLE TO NO CIGS...MAINLY SCT CONDITIONS FOR AHN. AFT 15Z...WOULD EXPECT ALL AREAS TO HAVE VFR CIGS. SOME SCT250 MAY CREEP INTO THE AREA OVERNIGHT FROM THE WEST. VISIBILITY...DEWPOINT DEPRESSIONS OF 5-10 DEGREES...WINDS 5-10KTS...AND CLOUD COVER PREVENTING ANY FOG DEVELOPMENT THIS MORNING. AIR MASS WILL DRY BEHIND FRONTAL SYSTEM...SO DO NOT FORESEE ANY FOG OR VISIBILITY PROBLEMS THROUGH THIS TAF VALID PERIOD...NOT EVEN FOR MCN. WX...NONE THROUGH THIS TAF VALID PERIOD. WINDS...W 5-10KTS EARLY...WILL BECOME NW 12-15KTS WITH GUSTS TO 20KTS AFT 15Z...THEN DIMINISH TO 5-10KTS AFT 00Z. && .PRELIMINARY POINT TEMPS/POPS... ATLANTA 68 41 60 41 / 0 0 5 40 ATHENS 74 41 63 41 / 0 0 0 20 GAINESVILLE 67 40 60 40 / 0 0 0 30 ROME 67 40 60 43 / 5 0 5 40 COLUMBUS 73 46 65 47 / 0 0 10 40 MACON 72 41 67 44 / 0 0 5 30 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 27/19 ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 927 AM EST FRI MAR 17 2006 .SHORT TERM (TODAY)... WELL...THE CRUX OF THE MORNINGS FORECAST IS THE SECONDARY SURGE OF LOW CLOUDS. THERE ARE 2 BANDS OF STRATUS AND STRATOCUMULUS. THE LARGEST ONE'S BACK EDGE STRETCHES FROM DEC-SRN IND-NRN CVG. THE SECONDARY LOW CLOUD BAND STRETCHES ACROSS THE NRN BUCKEYE STATE. THE FIRST LINE IS MOVING TO THE SOUTH AT 34 KTS. THE ILX SOUNDING CAPTURES THIS FEATURE WELL WITH SFC TO 800 MB 0-3 DEGREE TD SPREADS AND BACKING WINDS FROM BOUNDARY LAYER TO H7. LATEST RUC MODEL SHOWING LOW CLOUDS HOLDING IN SDF AND LEX THROUGH 18Z AND LIFTING BY 21Z. CURRENT FORECAST LOOKS GOOD IN TERMS OF TEMPERATURE AND SKY GRIDS SHOW NICE TRANSITION OF THE LOW CLOUDS THROUGH THE CWA. RUC SOUNDING AS WELL AS ILX AND OHX SOUNDING SHOWING HIGHS IN THE 47 RANGE ALONG I 64 AND AROUND 50 NEAR THE TN STATE LINE. ALL IN ALL FORECAST HUMMING ALONG NICELY. PREVIOUS DISCUSSION BELOW. SHORT TERM (TONIGHT) MAIN FOCUS FOR THIS FORECAST WILL BE CLOUD COVER AND COLD TEMPERATURES. ON THE WEATHER MAP THIS MORNING LOW PRESSURE WAS MOVING THROUGH THE WESTERN PORTION OF VIRGINIA WITH CLEAR SKIES OVER OUR FORECAST AREA. COLD AIR WILL ADVECT INTO THE LOWER OHIO VALLEY THROUGH THE DAY SO WE WILL SEE TEMPERATURES FALLING THIS MORNING INTO THE 40S AND GENERALLY HOLD STEADY THROUGH THE REMAINDER OF THE DAY. LOW CLOUDS OVER ILLINOIS AND INDIANA WILL ENTER THE NORTHERN PORTION OF THE CWFA AROUND 10Z AND OVERSPREAD THE REGION THIS MORNING. HAVE NOTICED A FEW LOCATIONS NORTH OF INDIANAPOLIS REPORTING SOME LIGHT RAIN OR DRIZZLE AT 07Z. WE FEEL THIS PRECIPITATION SHOULD DISSIPATE BEFORE IT ARRIVES IN OUR CWFA HOWEVER IF IT HOLDS TOGETHER AN UPDATE TO MENTION DRIZZLE MAY BE NEEDED. SKIES WILL CLEAR THIS EVENING AS COLD HIGH PRESSURE NUDGES INTO THE REGION. TEMPERATURES WILL FALL INTO THE MID AND UPPER 20S BY SATURDAY MORNING... SOME 10 TO 15 DEGREES BELOW NORMAL FOR THE MIDDLE OF MARCH. --JA .LONG TERM (SATURDAY THROUGH THURSDAY)... DAYS 2-3 (SATURDAY - SUNDAY NIGHT)... COOLER AND DRY PRETTY MUCH SUMS UP THIS TIME PERIOD. AXIS OF HIGH PRESSURE ORIGINATING FROM OUR NEIGHBORS TO THE NORTH WILL KEEP CONDITIONS DRY FOR SAT-SUN. RIDGING OVER THE CENTRAL PLAINS ON SAT WILL PROGRESS EASTWARD TOWARD OUR CWA BY SUNDAY NIGHT. WINDS WILL BE LIGHT AND FROM THE NNE SAT...SLOWLY VEERING AROUND TO THE E ON SUN AHEAD OF A WARM FRONT APPROACHING FROM THE SW. MAJORITY OF THE CWA WILL REMAIN MOSTLY SUNNY...EXCEPT FOR SW CWA BY SUNDAY AS HIGH CLOUDS WILL WORK THEIR WAY INTO SRN KY FROM APPROACHING STORM SYSTEM. TEMPS WILL ROUGHLY BE 6-10 DEGREES BELOW NORMAL OVER THE WEEKEND FOR HIGHS AND LOWS. SATURDAY HIGHS WILL RANGE FROM UPPER 40S TO LOW 50S...AND WILL BE SLIGHTLY WARMER ON SUNDAY. LOWS SUNDAY MORNING WILL DIP INTO THE UPPER 20S. DAYS 4-7 DISCUSSION (MONDAY - THURSDAY)... IN THIS PERIOD...A POTENT SOUTHERN STREAM STORM SYSTEM WILL BE THE FOCUS FOR WEATHER EARLY NEXT WEEK. EARLY MONDAY MORNING...STRONG SHORT WAVE AND ASSOCIATED SFC LOW WILL EJECT OUT OF THE TEXAS PANHANDLE REGION AND DEVELOP OVER THE SOUTHERN PLAINS. GULF MOISTURE WILL RIDE NORTHWARD ALONG A STRONG 850MB JET ASSOCIATED WITH WARM AIR ADVECTION...AND IN CONJUNCTION WITH AN ANTICYCLONICALLY CURVED UPPER JET OVER THE GREAT LAKES...THE LOW-LEVEL CONV AND UPPER-LEVEL DIV WILL HELP GENERATE SHWRS AND POSSIBLY TSTORMS AS WELL AS EARLY AS EARLY MONDAY MORNING ACROSS FAR SW CWA. WITH THIS LOW-LEVEL INFLUX OF WARMER TEMPS AND HIGHER MOISTURE...COULD SEE SOME NICE ELEVATED INSTABILITY AHEAD OF THE WARM FRONT MONDAY MORNING...MAINLY ACROSS SOUTHERN KY. WITH GOOD DIRECTIONAL AND SPEED SHEAR EXPECTED...COULD EASILY SEE SOME ELEVATED HAILERS NORTH OF THIS WARM FRONT ON MONDAY. THEREFORE WILL INSERT TSTORMS INTO GRIDS FOR MONDAY. WILL HAVE TO MONITOR FURTHER MODEL TRENDS AND SPC GUIDANCE TO SEE IF SEVERE WEATHER IS POSSIBLE WITH THIS EXPECTED ELEVATED CONVECTION. NOT SURE AT THIS POINT WHERE WARM FRONT WILL SET UP...BUT SOUTHERN KY LOOKS LIKE THE BEST CHANCE TO GET INTO WARM SECTOR. MODELS PROG MID 50 DEWPOINTS REACHING SRN KY MONDAY EVENING AHEAD OF COLD FRONT. HOWEVER I THINK MOST INSTABILITY WILL REMAIN SOUTH OF MY CWA AS THE TRACK OF THE LOW HAS BEEN SLIGHTLY FURTHER SOUTH WITH THE PAST FEW MODEL RUNS. HOWEVER...WILL KEEP TSTORM WORDING IN THROUGH MONDAY EVENING ACROSS SRN KY. TOO EARLY TO TELL IF ANY STORMS THAT DO FORM WOULD BE SEVERE...BUT GIVEN THAT THE 500MB LOW BECOMES NEGATIVELY TILTED AS THE SFC LOW STRENGTHENS...IT IS CERTAINLY POSSIBLE ALTHOUGH THE GREATEST CHANCE WOULD LIKELY BE TN AND SOUTHWARD. SOMETHING TO WATCH FOR SURE. BEHIND THIS COLD FROPA...LOW-LEVEL THICKNESS VALUES DROP BY TUESDAY MORNING CONSIDERABLY. GFS SHOWS A LOT OF QPF BEHIND THIS SYSTEM...ALTHOUGH MUCH OF IT REMAINS TO THE NORTH. COULD SEE SOME SNOW ON THE BACK SIDE OF THIS SYSTEM...ESPECIALLY ACROSS FAR NERN CWA...BUT AS PREVIOUS FORECASTER NOTED WILL LEAVE OUT FOR NOW HOPING FOR SOME CONSISTENCY IN THE MODELS. HPC SEEMED TO LIKE THE EUROPEAN MODEL OVER THE GFS...WHICH HAS A MORE NORTHERN TRACK AND WOULD BE POSSIBLY TOO WARM FOR SNOW. AGAIN...WILL LEAVE OUT FOR NOW. SYSTEM EXITS THE REGION TUESDAY NIGHT LEAVING WED AND THURS MOST LIKELY DRY. AGAIN...EXPECT A SLIGHT COOL DOWN FOR WED AND THURS...ROUGHLY HIGHS IN THE MID-UPPER 40S. AL && LMK WATCHES/WARNINGS/ADVISORIES... .IN...NONE. .KY...NONE. && $$ JDG/JA ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 558 AM EST FRI MAR 17 2006 .SHORT TERM... WELL...GFS AND NAM HV BEEN INTERNALLY CONSISTENT BUT DID NOT AGREE W/ EACH OTHER PAST SVRL RUNS. MUST SAY THE CRRNT RADAR MOSAIC LOOKS A LOT LIKE THE 06Z NAM AND ITS PARALLEL RUN. A BAND OF PCPN ACROSS WRN/NRN MD ATTM IN RGN OF GOOD H8-5 FRONTOGENETICAL FORCING. OTRW... LOPRES OVR NC MVG EWD HAS SHUNTED THE REST OF THE PCPN FM SE VA EWD. N/NE FLOW ACRS CWFA NOT HELPING...AS ITS ADVECTING DRY AIR ACRS CWFA. FLLWG THE NAM FWD...PCPN WL LINGER IN THE NW FOR A CPL MORE HRS BEFORE ITS GETS SHEARED APART. LTL/NO PCPN ELSW. W/ THAT IN MIND... THE OPPORTUNITY FOR ADVSRY LVL SNW IS JUST ABT DONE. WL BE UPDTG ZFP ETC ASAP...CANCELLING THE ADVSRY. WL PLACE 20-30 POPS IN THE N...AND RMVG PCPN ENTIRELY IN THE S. && .PREVIOUS DISCUSSION... SHORT TERM /TODAY/... WEAK LOW PRESSURE CENTERED OVER NORTHEASTERN NC AT 12Z THIS MORNING WILL MOVE RAPIDLY EASTWARD OFF THE COAST BY 15Z. RADAR TRENDS AND 00Z NAM AND 00Z RUC SUPPORT ONLY WEAK ISENTROPIC LIFT ACROSS CENTRAL VA BETWEEN 09Z AND 12Z WITH LIGHT QPF AND WEAKENING BAND OF PRECIPITATION MOVING FROM NORTHERN WV/NORTHWESTERN MD INTO NORTHERN VA AND NORTH CENTRAL MD. THESE TRENDS AND LATEST MODEL INDICATIONS POINT TOWARD MARGINAL SNOW ADVISORY ACCUMULATIONS...WHERE WET BULB EFFECT WILL BE STRONG ENOUGH TO CHANGE RAIN OR MIXTURE OF RAIN/SNOW TO ALL SNOW. 07Z TEMPERATURES IN ALL LOW ELEVATION SITES OF THE CWA IN THE 40S WITH QUITE A FEW OBS IN THE HIGH 40S SUGGEST THAT IT MAY TAKE LONGER TO TRANSITION TO ALL SNOW. WILL REMOVE WASHINGTON AND FREDERICK COUNTIES IN MD...MORGAN...BERKELEY...AND JEFFERSON COUNTIES IN WV...AND FREDERICK...CLARK AND LOUDOUN COUNTIES IN VA FROM THE SNOW ADVISORY...AS BEST POTENTIAL OVERRUNNING HAS SHIFTED SOUTH WITH RECENT MODEL RUNS. HIGH PRESSURE FROM CENTRAL CANADA WILL BUILD SLOWLY SOUTHWARD BEHIND THE DEPARTING LOW PRESSURE SYSTEM LATE THIS MORNING THROUGH THE REST OF THE DAY. WEAK TO MODERATE CAA WILL KEEP TEMPERATURES 4 TO 6 F BELOW NORMAL IN THE MID 40S TO LOWER 50S...DESPITE CLEARING SKIES AND A GOOD DEAL OF SUNSHINE BY LATE AFTERNOON ACROSS THE ENTIRE CWA. LONG TERM /TONIGHT THROUGH THURSDAY/... SPRAWLING AREA OF HIPRES NOSES IN FM CNDA TNGT...AND HOLDS THRU WKND. AMS DRY THRUT COLUMN...W/ SFC DEWPTS IN THE TEENS...AND H10-5 RH AOB 30 PCT. JUST ABT THE ONLY CONSIDERATION WL BE THE WND SAT... AS H8-5 LOW WL KEEP A DECENT GRADIENT ACRS AREA. H8 CAA AND SHEARED H5 VORT EMBEDDED IN FLOW WL ASSIST IN MIXING WNDS TO SFC. MOMENTUM TRANSFER SUGGESTING GUSTS 20-30 KT. BY SUN...HIPRES WL BE NEAR ENUF SO THAT WNDS WL BE LGTR. MOS TEMPS NOT FAR APART...AND BLEND GNLY TAKEN. SFC LOPRES DVLPG IN SRN CONUS MON MRNG WL NEED TO BE WATCHED...AS IT TOSSES MSTR TWD CWFA MON AFTN-TUE MRNG. 12Z GFS FASTER AT F84 AND MUCH MORE PROGRESSIVE THRAFTR COMPARED TO NAM. SFC HIGH WL BE ABLE TO WARD OFF INITIAL SURGE...BUT FOR HOW LONG? UNLIKE CRRNT SYSTM... THIS ONE WL HV PLENTY OF MSTR AVBL THX TO GLFMEX AND COOL AIR WL BE IN PLACE...SO PTYPE WL BE AN ISSUE. WL HOLD W/ CRRNT SET OF GRIDS... TACKLING ONE STORM AT A TIME. AVIATION... WEAK LOW WILL PASS ACROSS NORTHERN NC THIS MORNING WITH LIGHT PRECIPITATION DEVELOPING AT ALL TAF SITES BETWEEN 08Z AND 10Z...BUT DESPITE PRECIPITATION EXPECT VFR CIGS AND VSBYS TO PREDOMINATE. BEST CHANCE FOR IFR CONDITIONS WILL BE FOR A BRIEF WINDOW FROM 10Z-12Z AT MRB/IAD/DCA/BWI/MTN AND 10Z-13Z AT CHO. LOW WILL MOVE QUICKLY OFF THE NC COAST AFTER 12Z...AND DRIER AIR WILL FILTER INTO THE REGION WITH NORTH WINDS LESS THAN 10 KT THROUGH THE REMAINDER OF THE DAY. VFR CONDITIONS ARE EXPECTED FROM 12Z FRIDAY THROUGH 12Z SATURDAY...EXCEPT AT CHO WHERE VFR WILL BEGIN AT OR ABOUT 13Z. MARINE... NLY FLOW AOB 10 KT ACRS WATERS TDA. TNGT...CAA AND PVA WL COMBINE TO PROVIDE BRZY CONDS ACRS THE WATERS...WHERE MIXING SHUD BE GOOD THX TO LAPSE RATES. BASED UPON MOMENTUM TRANSFER FM HRLY SNDGS...CUD SEE SCA TYPE WNDS SAT...FM ELY MRNG THRU EVE. HIPRES BLDG ACRS WATERS WL ENSURE CONDS ARENT PROLONGED BYD THAT. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY FOR ANZ530>537 FROM 1 AM SATURDAY TO 1 AM SUNDAY. && $$ UPDATE...HTS SHORT TERM/AVIATION...SMITH LONG TERM/MARINE...HTS md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1051 AM EST FRI MAR 17 2006 .DISCUSSION... THE MAIN CONCERN WITH THIS FORECAST UPDATE IS WITH THE CLOUD COVER OVER THE FORECAST AREA THIS AFTERNOON. WATER VAPOR IMAGERY AND RUC/NAM SHOWING A CLOSED LOW OVER NORTHEAST MAINE...A RIDGE OVER THE NORTHERN HIGH PLAINS EXTENDING INTO ALBERTA...AND A LONGWAVE TROUGH ALONG THE WEST COAST. SURFACE ANALYSIS INDICATES A RIDGE STRETCHING FROM CENTRAL CANADA SOUTH THROUGH NORTHERN HIGH PLAINS...AND A LOW OVER BRITISH COLUMBIA WITH A STATIONARY FROM EXTENDING SOUTH ALONG THE WESTERN CONTINENTAL DIVIDE. VISIBLE SATELLITE AND SURFACE REPORTS INDICATE A LOW CLOUDS SHOWING UP OVER SOUTH CENTRAL LAKE SUPERIOR. THESE ARE DUE TO COLD AIR MOVING OVER THE RELATIVELY WARM LAKE SUPERIOR. A WEAK SHORTWAVE WILL SLIDE DOWN THE LEE OF THE HIGH PLAINS RIDGE AND THROUGH THE UPPER GREAT LAKES. THE SURFACE RIDGE WILL EDGE EAST INTO WESTERN ONTARIO...REMAIN NEARLY STATIONARY OVER THE UPPER MISSISSIPPI RIVER VALLEY. THIS IS CAUSING WINDS TO GRADUALLY SHIFT WEST AND SOUTHWEST AND REMAIN LIGHT. SOUNDING FORECAST SHOWING AIR MASS WILL BE VERY DRY ABOVE 3K FEET...AND LOW LEVEL MOISTURE PRESENT. GFS/NAM MODELS SHOWING LOW LEVEL MOISTURE WILL DRY A BIT THIS AFTERNOON AND ISENTROPIC ANALYSIS INDICATE THAT SUBSIDENCE WILL INCREASE. THIS WILL CAUSE SOME OF THE CLOUDS COVER TO DISSIPATE OVER THE FORECAST AREA. THUS WILL UPDATE THE FORECAST PACKAGE TO TAKE OUT A MENTION OF FLURRIES THIS MORNING BUT LEAVE THE REST THE SAME FOR NOW. && .MQT...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DLG mi