Issued by NWS Charleston, WV
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-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --000 FXUS61 KRLX 111104 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 559 AM EST WED FEB 11 2009 .SYNOPSIS... STRONG COLD FRONT PASSES THIS AFTERNOON WITH GUSTY SHOWERS AND THUNDERSTORMS. THERE IS POTENTIAL FOR STRONG WINDS TONIGHT...AND CONTINUING THURSDAY IN THE MOUNTAINS. && .NEAR TERM /THROUGH TONIGHT/... MODELS IN EXCELLENT AGREEMENT WITH STRONG LOW PRESSURE AND COLD FRONT THAT RAPIDLY CROSS THE AREA THIS AFTERNOON AND EARLY EVENING. THIS MORNING WILL BE MOSTLY PRECIP FREE AS ENERGY RELOADS BACK WEST WITH THE RAPIDLY APPROACHING SYSTEM. THE SURFACE LOW WILL BE DEEPENING AS IT TRACKS RAPIDLY FROM THE SOUTHERN PLAINS TO THE GREAT LAKES TODAY. THE FRONT IS PROGGED TO ENTER OUR WESTERN BORDER AROUND 19Z...AND EXIT THE MOUNTAINS JUST AFTER 00Z. EXPECT THE PRECIP TODAY WILL MOSTLY BE IN THE FORM OF A NARROW BAND OF CONVECTION ASSOCIATED WITH THE COLD FRONT. WHILE PRECIP AMOUNTS WILL BE UNIMPRESSIVE DUE TO THE SPEED OF THE FRONT...THE WIND WILL BE THE BIG STORY. EVERYTHING IS IN PLACE FOR A WIDESPREAD AND SIGNIFICANT WIND DAMAGE EVENT...ESPECIALLY LATER THIS AFTERNOON AND TONIGHT. WE HAVE A DEEPENING SURFACE LOW AS IT TRACKS NORTHEASTWARD UNDER A STRONGLY NEGATIVELY TILTED UPPER TROUGH. GOOD MODEL AGREEMENT ON WESTERLY WINDS IN EXCESS OF 70 MPH AT 850 MB ALONG AND BEHIND THE FRONT. ENOUGH INSTABILITY FOR THUNDERSTORMS ALONG THE FRONT...SO THERE IS EASY POTENTIAL FOR THESE STORMS TO BRING DAMAGING WINDS TO THE SURFACE. THUS...WE ARE UNDER A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON. IN ADDITIONAL...STRONG COLD ADVECTION WITH THESE WINDS BEHIND THE FRONT WILL LIKELY PRODUCE SOME DAMAGING WINDS. THUS...THE HIGH WIND WATCH HAS BEEN UPGRADED TO A HIGH WIND WARNING FOR THE ENTIRE AREA...WITH SURFACE WIND GUSTS IN EXCESS OF 60 MPH POSSIBLE. THE WARNING RUNS FROM THIS AFTERNOON THROUGH TONIGHT...EXCEPT CONTINUING THURSDAY IN THE NORTHERN MOUNTAINS. EXPECT TEMPS AROUND 70 DEGREES IN MANY PLACES BEFORE THE COLD FRONT ARRIVES...ON THE WARM SIDE OF GUIDANCE...ALONG WITH INCREASING SOUTHERLY WINDS AHEAD OF THE FRONT. MOST OF THE SHOWERS WILL END BY EARLY TONIGHT...EXCEPT FOR SOME WRAPAROUND OVER SOUTHEAST OHIO TONIGHT...AND UPSLOPE SHOWERS OVER THE MOUNTAINS. COLDER TONIGHT...AND THERE MAY BE A CHANGE OVER TO SNOW SHOWERS IN THE HIGHER ELEVATIONS OF THE NORTHERN MOUNTAINS LATE TONIGHT. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... WINDS WILL REMAIN A PROBLEM THROUGH THE DAY ON THURSDAY...WITH 850MB WINDS STILL 45-55 KNOTS. BUFKIT SOUNDINGS INDICATE MIXING TO AT LEAST 900-850MB LEVEL EVEN INTO THURSDAY AFTERNOON...SO I EXPECT STOUT GUSTS TO CONTINUE TO BE REALIZED AT THE SURFACE. THE GOOD NEWS IS THAT THE MAIN COLD AIR ADVECTION WILL HAVE ALREADY OCCURRED BY THURSDAY MORNING...WITH NEAR NEUTRAL ADVECTION DURING THE DAY. THE VERY STEEP SURFACE PRESSURE GRADIENT AT THE START OF THE DAY...WILL GRADUALLY DECREASE IN MAGNITUDE...AS THE DEEP SURFACE LOW QUICKLY ZIPS FROM THE EASTERN GREAT LAKES IN THE MORNING...TO NOVA SCOTIA BY 00Z FRI. HIGH WIND WARNING WILL CONTINUE THROUGH THURSDAY FOR POCAHONTAS/RANDOLPH COUNTIES...WHICH WITH THE HIGHER TERRAIN WILL BE THE MOST EXPOSED AND VULNERABLE TO CONTINUED WARNING CRITERIA GUSTS /58 MPH OR MORE/. FOR THE REST OF THE AREA...ANTICIPATING ADVISORY CRITERIA GUSTS /46-57 MPH/ WILL CONTINUE TO BE POSSIBLE THROUGH THE DAY. SURFACE HIGH PASSES THURSDAY NIGHT INTO FRIDAY...THOUGH HIGH CLOUDS WILL BE STREAMING IN WELL AHEAD OF THE NEXT DISTURBANCE IN OUR QUICKLY MOVING ZONAL FLOW. && .LONG TERM /SATURDAY THROUGH TUESDAY/... MEAN WESTERN TROUGH DURING THIS PERIOD...EJECTS MULTIPLE WAVES OF ENERGY ACROSS THE REST OF THE COUNTRY THROUGH THE FAST MOVING ZONAL TO WEST-SOUTHWEST FLOW. FORECAST CONFIDENCE QUICKLY DROPS AFTER SATURDAY...BECAUSE OF RUN-TO-RUN AND MODEL-TO-MODEL INCONSISTENCIES WITH WHEN/IF INDIVIDUAL WAVES IMPACT OUR REGION. I MOSTLY LEFT THE PREVIOUS FORECAST INTACT SATURDAY ONWARD...EXCEPT TO ADD LOW CHANCE POPS TO FORECAST FOR SUNDAY BECAUSE OF UNCERTAINTY. LATEST RUNS OF GFS AND ECMWF ATTEMPT TO RESOLVE ANOTHER WAVE TO POSSIBLY GIVE LIGHT PRECIPITATION TO THE AREA DURING THAT TIME. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...-- Changed Discussion --12Z WEDNESDAY THRU 12Z THURSDAY... BIG STORY THIS PERIOD WILL BE THE HIGH WIND POTENTIAL LATER THIS AFTERNOON AND EARLY TONIGHT UPON PASSAGE OF A VERY STRONG COLD FRONT...WITH GUSTS IN EXCESS OF 60 MPH POSSIBLE. MOST OF THE RAIN SHOWERS HAVE LIFTED NORTH OUT OF THE AREA AT 11Z. FOR TODAY...EXPECT VFR UNTIL A LINE OF SHOWERS AND THUNDERSTORMS ASSOCIATED WITH THE COLD FRONT...ACCOMPANIED BY STRONG WINDS...MOVES RAPIDLY EASTWARD ACROSS THE AREA THIS AFTERNOON AND EARLY EVENING. BEHIND THE FRONT...MAINLY VFR CEILINGS...EXCEPT BECOMING MAINLY MVFR MOUNTAINS IN UPSLOPE SHOWERS. THE STRONG WINDS WILL CONTINUE FOR AT LEAST SEVERAL HOURS BEHIND THE FRONT IN THE STRONG COLD ADVECTION. AVIATION OUTLOOK /BEYOND 12Z THURSDAY/... STRONG WINDS CONTINUE THROUGH THE DAY THURSDAY...ESPECIALLY FOR MOUNTAIN TERMINALS. LOCALLY IFR POSSIBLE IN UPSLOPE SHOWERS FOR HIGHER MOUNTAIN ELEVATIONS THROUGH THURSDAY MORNING.-- End Changed Discussion --&& .RLX WATCHES/WARNINGS/ADVISORIES... WV...HIGH WIND WARNING FROM 1 PM THIS AFTERNOON TO 6 AM EST THURSDAY FOR WVZ005>011-013>020-024>040. HIGH WIND WARNING FROM 1 PM THIS AFTERNOON TO 4 PM EST THURSDAY FOR WVZ046-047. OH...HIGH WIND WARNING FROM 1 PM THIS AFTERNOON TO 6 AM EST THURSDAY FOR OHZ066-067-075-076-083>087. KY...HIGH WIND WARNING FROM 1 PM THIS AFTERNOON TO 6 AM EST THURSDAY FOR KYZ101>103-105. VA...HIGH WIND WARNING FROM 1 PM THIS AFTERNOON TO 6 AM EST THURSDAY FOR VAZ003-004. && $$ SYNOPSIS...MDP/JMV NEAR TERM...JMV SHORT TERM...MDP LONG TERM...MDP/ESS AVIATION...JMV
