877 FXUS61 KRLX 232349 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 749 PM EDT MON APR 23 2012 .SYNOPSIS... MOUNTAIN SNOW SHOWERS DIMINISH OVERNIGHT AS A SYSTEM EXITS TO THE NORTH. A WARM FRONT CROSSES WEDNESDAY NIGHT...AND THEN A COLD FRONT CROSSES THURSDAY. HIGH PRESSURE BUILDS IN BRIEFLY ON FRIDAY. && .NEAR TERM /THROUGH TUESDAY/... 730 PM UPDATE... SCOURED OUT THE LOW CLOUDS AS THE ATMOSPHERE IS WELL MIXED AND RATHER DRY IN THE STRONG AND GUSTY WNW FLOW. RAISED TEMPERATURES AND LOWERED DEW POINTS EARLY ON PER MIXING BUT FCST APPEARS ON TRACK AFTER THAT...INCLUDING LOWS TUE MORNING. 430 PM UPDATE... BY DESIGN...CANCELLED THE WINTER WEATHER ADVISORIES FOR THE NORTHERN MOUNTAINS OF WV...AS THE PRECIPITATION TAPERS OFF IN A DEEPENING MIXING LAYER. ISSUED A FREEZE WARNING FOR NORTHERN WEST VIRGINIA AND SOUTHEAST OHIO INTO TUESDAY MORNING...FREEZE ONGOING IN SNOWSHOE. PREV DISCN... 5H TROUGH LIFTING NORTH OF THE FORECAST AREA...WITH HEIGHT CHANGE FIELDS REBOUNDING INTO POSITIVE TERRITORY. SOME PESKY WRAP AROUND MOISTURE STILL MOVING INTO NORTHEASTERN ZONES...BUT OVER THE PAST COUPLE OF HOURS...MOISTURE FLUX HAS BEEN ON THE DECREASE. MODELS ALL IN GENERAL AGREEMENT IN HANDLING THE EXIT OF THIS SPRING SNOWSTORM...AND THE ATMOSPHERIC COLUMN GOES THROUGH A DRYING TREND...WITH SOME WARMING NOTED AS WELL. WILL GRADUALLY TAPER POPS DOWN IN THE MOUNTAIN COUNTIES INTO THE CHC CATEGORY. WSW ADVISORIES WILL NEED TO BE DROPPED SOONER. THINKING THAT SOME NIGHT TIME STRATUS MAY REDEVELOP...ESPECIALLY AS WE ARE NOW ENTERING A MOUNTAIN UPSLOPE REGIME AS FAR AS THE ATMOSPHERE IS CONCERNED. IN ADDITION...85H THERMAL TROUGH IS SLOW TO LIFT WHICH BODES WELL FOR SOME LOW LEVEL CLOUD DEVELOPMENT. FOR TEMPS...INHERITED TEMPS LOOK GOOD AND IN LINE WITH GUIDANCE. ONLY MADE SOME MINOR ADJUSTMENTS. SINCE MANY PLACES HEADED BELOW THE FREEZING MARK...WILL OPT FOR A FREEZE WARNING FOR MUCH OF THE NORTHERN TIER OF THE CWA ONCE THE WINTER HEADLINES DROPPED. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... LOOKING FOR EASTERN CONUS TROF AXIS TO SLIDE EAST TUE NIGHT INTO WED WITH RECOVERING UPR HEIGHTS. CLOSER TO SFC WILL BE DEALING WITH WARM FRONTAL PASSAGE WED NIGHT FOLLOWED QUICKLY BY A COLD FRONTAL PASSAGE ON THU. INSERTED SOME CAT POPS WED NIGHT SOUTHERN HALF OF AREA WITH WARM FRONTAL PASSAGE WHICH WILL BE AIDED BY AND UPR DISTURBANCE ALOFT. INSERTED SOME SCHC THUNDER WITH SHOWALTER INDICES GOING NEGATIVE WITH SOME ELEVATED INSTABILITY POSSIBLE WITH WARM FRONT. AREA BRIEFLY GETS IN TO WARM SECTOR ON THU BEFORE SUBSEQUENT COLD FRONT CROSSES LATE. BOTH NAM AND GFS ARE QUITE ROBUST WITH LLVL MOISTURE ADVECTION AHEAD OF COLD FRONT ON THU...LEADING TO SOME IMPRESSIVE DEWPTS/SFC CAPE. THINK THIS MAY BE OVERDONE SOME. DO THINK THERE WILL BE SOME FRONTAL/PREFRONTAL CONVECTION TO DEAL WITH THOUGH AND HAVE CODED UP SOME LKLY POPS IN AFTN. STARTED WITH A BLEND OF GUIDANCE BEFORE GOING WITH WARMER NUMBERS AT NIGHT IN WAA AND BL PUFF. THU COULD END UP BEING ON THE WARM SIDE...DEPENDING ON AMNT OF CLOUD COVER IN WARM SECTOR. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... UNSETTLED WEATHER EXPECTED IN THE LONG TERM. ELECTED TO FOLLOW HPC GUIDANCE IN THE LONG TERM...WHICH CLOSELY FOLLOWS THE 00Z APRIL 23 ECMWF. SOME LINGERING PRECIPITATION WILL BE AROUND THE AREA EARLY FRIDAY AS A LOW PRESSURE SYSTEM PUSHES OFF TO OUR EAST...AND ITS ASSOCIATED COLD FRONT SINKS TO...AND EVENTUALLY STALLS TO OUR SOUTH. HIGH PRESSURE WILL THEN BRIEFLY BUILD IN FROM THE NORTH FOR A BRIEF BREAK IN THE PRECIPITATION FOR MUCH OF FRIDAY. THE STALLED FRONTAL BOUNDARY TO THE SOUTH WILL THEN BEGIN TO LIFT BACK NORTH LATE SATURDAY/EARLY SUNDAY AS A WARM FRONT AS ANOTHER LOW PRESSURE SYSTEM ACROSS THE PLAINS APPROACHES THE AREA...WITH ITS ASSOCIATED COLD FRONT AND ACCOMPANYING SHOWERS AND THUNDERSTORMS SWEEPING THROUGH THE AREA ON SUNDAY. OUT AHEAD OF THE COLD FRONT SUNDAY...TEMPERATURES WILL WARM NICELY TO THE UPPER 60S TO 70S FOR MANY AREAS...WITH COOLER TEMPERATURES EXPECTED EARLY NEXT WEEK BEHIND THE FRONT. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... STRONG AND GUSTY WNW FLOW THROUGH THE PERIOD WILL KEEP THE ATMOSPHERE DRY AND WELL MIXED...SO VFR FLIGHT CONDITIONS...EXCEPT BRIEF MVFR VSBY IS STILL POSSIBLE IN THE NORTHERN MOUNTAINS OF WV OVERNIGHT...IN SNOW SHOWERS. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z WEDNESDAY... FORECAST CONFIDENCE...HIGH. ALTERNATE SCENARIOS: TEMPO MVFR VSBY IN SNOW SHOWERS CODED UP FOR EKN OVERNIGHT MAY NOT HAPPEN. THE STRONG AND GUSTY WINDS WILL FLUCTUATE IN SPEED AND DIRECTION. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE TUE 04/24/12 UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11 EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY H H H H H H H H H H H H PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H H H H H H H H H H AFTER 00Z WEDNESDAY... IFR POSSIBLE IN SHOWERS AND POSSIBLE THUNDERSTORMS EARLY THU MORNING THROUGH MIDDAY THU...AS A WARM FRONT MOVES THROUGH. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FREEZE WARNING FROM 2 AM TO 10 AM EDT TUESDAY FOR WVZ008>011- 016>020-027>037-039-040. FREEZE WARNING UNTIL 11 AM EDT TUESDAY FOR WVZ038-046-047. OH...FREEZE WARNING FROM 2 AM TO 10 AM EDT TUESDAY FOR OHZ066-067- 075-076-083>085. KY...NONE. VA...NONE. && $$ SYNOPSIS...KMC/TRM/SL/30 NEAR TERM...KMC/TRM SHORT TERM...30 LONG TERM...SL AVIATION...TRM