Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 271912 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 212 PM EST THU NOV 27 2014 .SYNOPSIS...
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NORTHWEST FLOW/UPSLOPE SNOW THROUGH TONIGHT. HIGH PRESSURE FRIDAY AND SATURDAY. ANOTHER SYSTEM SUNDAY INTO MONDAY.
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&& .NEAR TERM /THROUGH TONIGHT/...
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TRANSITIONING TO NORTHWEST FLOW IN THE LOWER LEVELS THIS AFTERNOON WITH A MINOR LEAGUE UPSLOPE SNOW EVENT ON TAP FOR THIS EVENING AND TONIGHT. COLD ADVECTION BRINGS -10C AND LOWER AIR AT THE 850MB BY TONIGHT WHICH WILL HELP WITH THE LAPSE RATES AND ALLOW FOR AUTO CONVECTION TO OCCUR. ADDED THE BULK OF THE CWA INTO SLIGHT CHANCE POPS IN THIS SCENARIO...THOUGH MOST PRECIPITATION...WHICH MAY BE A RAIN/SNOW MIX AT AROUND 35F OVER THE NEXT 3 HOURS...SHOULD BE INSIGNIFICANT. RESERVE THE ACCUMULATION POTENTIAL FOR THE TYPICAL UPSLOPE AREAS IN THE EASTERN HIGHLANDS...CONCENTRATING ON THE NORTHERN MOUNTAINS. THINKING THAT THE 2 INCH MARK IS A GOOD NUMBER FOR MOST AREAS ABOVE ABOUT 2000FT...BUT THE HIGHEST WINDWARD RIDGES ABOVE 4000FT COULD SEE UP TO 4 INCHES. THIS SHOULD BE ISOLATED HOWEVER AND WILL NOT PUT OUT ANY HEADLINES. WILL RECOMMEND TO THE EVENING SHIFT AN SPS MIGHT BE USEFUL LATER THIS EVENING TO COVER THE LIGHT SNOW. LAPSE RATES COLLAPSE AFTER 06Z FRIDAY...SO WILL SEE THE END OF THE MOUNTAIN SNOW BY 12-15Z. WILL GO RIGHT INTO WARM AIR ADVECTION OVER THE LOW LEVELS IN A TIGHT TEMPERATURE GRADIENT AT 850MB WITH MOISTURE PROGS HINTING AT A WARM FRONT PUSHING THROUGH FRIDAY AFTERNOON. THIS IS THE REASON FOR THE RETURN OF THE CLOUDS SO QUICKLY AFTER THE LOW LEVEL STRATUS FROM THE COLD ADVECTION DISSOLVES. GOT ANOTHER DAY OF CHILLY TEMPERATURES AFTER TEENS/20S IN THE MOUNTAINS/LOWLANDS TONIGHT BEFORE IMPROVEMENT IN THIS AREA THIS WEEKEND. 40F POSSIBLE IN THE TRI STATE AREA...BUT THAT WILL BE ABOUT IT.
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&& .SHORT TERM /FRIDAY THROUGH SUNDAY/...
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HIGH PRESSURE OFF TO THE SOUTHEAST TO START THE PERIOD...WITH NW FLOW ALOFT KEEPING SOME CLOUDS ACROSS THE FORECAST AREA. THINGS DRY OUT SATURDAY UNDER ZONAL FLOW...THEN TURNING MORE SOUTHWESTERLY BY LATE IN THE DAY WHICH BEGINS RETURNING LOW LEVEL MOISTURE. HOWEVER THE ATMOSPHERE REMAINS VERY DRY ABOVE AROUND 800MB. WITH THIS DRY AIR ALOFT IN PLACE...DELAYED ONSET OF ANY POPS INTO SATURDAY NIGHT. ENVISION A LOW STRATUS DECK IN PLACE...WITH PERIODS OF LIGHT RAIN ACROSS WESTERN CWA SATURDAY NIGHT AND SUNDAY. USED A RAW CONSENSUS BLEND FOR LOWS...WITH A SLIGHTLY NON-DIURNAL TREND FRIDAY NIGHT AS SURFACE FLOW BECOMES SOUTHERLY. BLENDED BIAS-CORRECTED ECMWF INTO HIGHS.
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&& .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... USED A BLEND OF THE ECMWF ENSEMBLE MEAN AND THE CURRENT FORECAST. NEXT FRONTAL BOUNDARY PUSHES INTO THE REGION SUNDAY NIGHT INTO MONDAY. MODELS THEN SHOW A WAVE MOVING ALONG THE FRONT FOR TUESDAY...BUT QUESTIONABLE HOW MUCH OF THAT EFFECTS THE CENTRAL APPALACHIANS. ECMWF AND GFS THEN DIVERGE CONSIDERABLY FOR WEDNESDAY AND THURSDAY. USING THE ECMWF ENSEMBLE MEAN BRINGS A FRONT THROUGH ON WEDNESDAY WITH SOME UPSLOPE SNOW POSSIBLE BEHIND THE FRONT WEDNESDAY NIGHT INTO THURSDAY. && .AVIATION /19Z THURSDAY THROUGH TUESDAY/... NORTHWEST FLOW WILL RESULT IN UPSLOPE SNOW FOR THE EASTERN TERMINALS FOR THE BULK OF THE TAF PERIOD. MVFR CEILINGS WILL BE A GOOD BET FOR PREVAILING GOING FORWARD AND WILL TAKE VISIBILITIES DOWN TO IFR AS THE CHANCES INCREASE FOR SNOW SHOWERS. CKB/EKN/BKW ARE THE BEST BETS FOR PREVAILING SNOW CONDITIONS AFTER 21Z TODAY. CANNOT RULE BRIEF SNOW CONDITIONS AT CRW AND PKB. MET AND MAV GUIDANCE LOOKED TO BE TOO OPTIMISTIC IN TERMS OF VISIBILITIES AT CKB AND BKW. IN GENERAL...CEILINGS TO LIFT TO VFR AFTER 12Z...PERHAPS A COUPLE HOURS LATER FOR THE MOUNTAINS. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: VSBY OVER MOUNTAIN COUNTIES...INCLUDING BKW...MAY BE MORE VARIABLE THAN INDICATED. 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. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EST 1HRLY 13 14 15 16 17 18 19 20 21 22 23 00 CRW CONSISTENCY H H H H H H H H M M M M 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 M M M M L L L L PKB CONSISTENCY M H H H H H H H H M H H CKB CONSISTENCY H H H H H H H H H H H M AFTER 18Z FRIDAY... IFR CONDITIONS IN SNOW SHOWERS MAY LINGER INTO EARLY FRIDAY OVER WV MOUNTAINS. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...RPY/MZ/26 NEAR TERM...26 SHORT TERM...MZ LONG TERM...RPY AVIATION...26

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