Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 241955 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 255 PM EST WED DEC 24 2014 .SYNOPSIS... COLD FRONT BRINGS GUSTY WINDS AND SHOWERS INTO THIS EVENING. CHRISTMAS DAY STARTS COLD...CLOUDY...AND WINDY...WITH A FEW RAIN AND SNOW SHOWERS. HIGH PRESSURE CHRISTMAS NIGHT INTO SATURDAY. && .NEAR TERM /THROUGH THURSDAY/... MODELS CONTINUE TO DRIVE A STRONG COLD FRONT EASTWARD ACROSS THE AREA THIS AFTERNOON AND EVENING...ACCOMPANIED BY A BAND OF SHOWERS AND A FEW THUNDERSTORMS. STILL SHOWING A MODERATE WESTERLY 850MB JET... PUNCHING IN BEHIND THE FRONT...AND LIFTING UP ACROSS THE LOW LANDS AND NORTHERN MOUNTAINS. THIS COUPLED WITH A TIGHT AND IMPRESSIVE COLD ADVECTION THERMAL PATTERN WILL GREATLY ENHANCE DOWNWARD MOMENTUM TRANSFER...FIRST WITH THE SHOWERS AND FOR SEVERAL HOURS BEHIND THE FRONT. THUS...WILL CONTINUE THE WIND ADVISORY FOR NORTHWESTERN TWO THIRDS OF THE AREA TIL 10 PM EST THIS EVENING. WHILE GUSTY WINDS WILL CONTINUE FOR AWHILE AFTER 10 PM...LOSS OF MIXING THRU HEATING AND LESSENING OF THE THERMAL GRADIENT WILL DECREASE THE WINDS FROM WEST TO EAST. FOR TEMPERATURES...THERE WILL BE A STRONG TEMPERATURE DROP BEHIND THE FRONT...BUT ABNORMALLY WARM TEMPERATURES AHEAD OF THE FRONT WILL BE FOLLOWED BY ONLY SEASONAL TEMPERATURES TONIGHT AND CHRISTMAS DAY. SO...POST FRONTAL RAIN SHOWERS WILL STRUGGLE TO CHANGE TO SNOW SHOWERS BEFORE ENDING FOR THE MOST PART FROM WEST TO EAST TONIGHT. THE EXCEPTION WILL BE THE HIGHER ELEVATIONS OF THE NORTHERN MOUNTAINS WHERE RAIN WILL CHANGE TO SNOW...BUT LITTLE SNOW ACCUMULATION IS EXPECTED AS DEEPER MOISTURE IS LOST BY THE TIME OF CHANGEOVER. ON CHRISTMAS DAY...LOTS OF LOW CLOUDS IN THE MORNING....BREAKING FOR SOME SUNSHINE IN THE AFTERNOON AS HIGH PRESSURE AND MUCH DRIER AIR SETTLES IN FROM THE WEST. LOOK FOR HIGHS IN THE 40S. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... WITH MOISTURE IN THE MOUNTAINS SHOWN TO BECOME LESS THAN 1.5 KFT THICK IN THE NRN MOUNTAINS BY 00Z FRI...AND THE TOP OF THE CLOUD AT -5C OR WARMER...OPTED TO CUT OFF UPSLOPE RAIN/SNOW SHOWERS THERE BY THEN TO START THE PERIOD. COLD ADVECTION IS CUT OFF AS COLD CORE SHIFTS E...AND HIGH PRESSURE TAKES OVER AT THE SFC BENEATH UPPER LEVEL RIDGING. THE HIGH MAINTAINS ITS INFLUENCE ON THE WEATHER AS IT BECOMES ANCHORED OVER THE MIDDLE ATLANTIC STATES FRI AND REMAINS SO THROUGH FRI NT...BEFORE DRIFTING EWD...OFFSHORE...ON SAT. THIS SPELLS DRY WEATHER WITHOUT MUCH CLOUD...ONCE THE CLOUDS IN THE NRN MOUNTAINS GRADUALLY BREAK UP THU NT. CLOUDS...MAINLY HIGH...INCREASE SAT AFTERNOON AS A LARGE POSITIVE TILT UPPER LEVEL S/W TROUGH AND SFC COLD FRONT APPROACH. MODELS CONTINUE TO TREND SLOWER WITH THIS FEATURE...LIKELY OWING TO THE TENACIOUS UPPER LEVEL HIGH OVER THE BAHAMAS. THUS HAVE SLOWED THE CHANCE FOR PRECIPITATION INCREASING FROM THE W...LIMITING IT TO JUST A SCHC ALONG AND W OF THE OHIO RIVER BY THE END OF THE DAY SAT. BLENDED IN THE MET AND MAV FOR LOWS THU NT...A LITTLE HIGHER OVER THE MIDDLE OHIO VALLEY ON ACCOUNT OF THE GRADIENT ON THE BACK SIDE OF THE HIGH THERE...AND A LITTLE LOWER ELSEWHERE WITH GOOD RADIATIVE COOLING IN THE VALLEYS. BLENDED IN THE MET FOR LOWS A LITTLE LOWER FRI NT WITH LESS CLOUD AND HIGH PRESSURE KEEPING THE FLOW LIGHT ESPECIALLY S AND E OF THE OHIO RIVER. BLENDED IN THE MET FOR HIGHS FRI FOR LITTLE CHANGE. RAISED HIGHS SAT A LITTLE ABOVE CONSENSUS AND GENERALLY ABOVE THE STRAIGHT GUIDANCE AND BELOW THE BIAS CORRECTED GUIDANCE. WITH LESS CLOUD...SAT SHOULD NOT BE MUCH IF ANY COOLER THAN FRI. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... MAIN SYNOPTIC FEATURE FOR THE LONG TERM IS A COLD FRONT PASSING THROUGH AND THEN A SECONDARY WAVE RIDING ALONG THE FRONT. THE GFS CONTINUES TO SUPPRESS THE SECOND WAVE...KEEPING IT MAINLY SOUTH AND EAST. THE LATEST ECMWF IS TRENDING THIS WAY AS WELL. STARTED WITH WPC GUIDANCE...AND THEN BLENDED IN ANOTHER DOSE OF THE GFS. HAVE THE COLD FRONT PASSING THROUGH ON SUNDAY WITH LIKELY POPS ACROSS MUCH OF THE CWA. THEN HAVE ANOTHER AREA OF LIKELY POPS ACROSS MAINLY THE COAL FIELDS AND SOUTHERN MOUNTAINS SUNDAY NIGHT INTO EARLY MONDAY WITH THE SECONDARY WAVE. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... 18Z WEDNESDAY THRU 18Z THURSDAY... DEEPENING SURFACE LOW WILL MOVE NORTH FROM CENTRAL KENTUCKY AT 16Z INTO CENTRAL MICHIGAN BY 00Z. PRESSURE GRADIENTS WILL CONTINUE TO TIGHTEN AND COLD FRONT PASSAGE WILL TAKE PLACE THIS AFTERNOON AND EVENING. LOOK FOR THE FRONT AT THE OHIO RIVER AROUND 19Z...CRW-CKB AROUND 21Z AND IN THE MOUNTAINS BY 23Z. SOME DRY SLOTTING THIS AFTERNOON AHEAD OF THE FRONT WILL KEEP VFR CONDITIONS WITH MINIMAL SHOWERS...AND THE LINGERING LIGHT RAIN IN THE MOUNTAINS WILL MOSTLY END BY 18Z. THEN EXPECT A ROUND OF GUSTY SHOWERS AND ISOLD TO SCT THUNDERSTORMS WITH THE COLD FRONT. SOUTHWESTERLY WIND GUSTS OF 40 TO 50 KTS KTS POSSIBLE ALONG AND BEHIND THE FRONT FOR A FEW HOURS...ESPECIALLY IN THE CONVECTION ALONG THE COLD FRONT ITSELF. AFTER 03Z WINDS SLOWLY DIMINISH...BUT STILL UP AROUND 30S KTS IN THE HIGHER MOUNTAIN ELEVATIONS...AND MVFR STRATUS SPREADS EASTWARD IN THE COLD ADVECTION ACROSS THE AREA...WITH IFR CEILINGS IN THE MOUNTAINS AFTER 07Z. AFTER 13Z...CONDITIONS IMPROVING TO VFR IN THE WEST AND MVFR IN THE MOUNTAINS. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z THURSDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING OF AFTERNOON STORMS AND OVERNIGHT STRATUS MAY VARY A FEW HOURS. 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 M M M H M M M M M M HTS CONSISTENCY M M M H H M M M M H M H BKW CONSISTENCY H H H M M H H M H H H H EKN CONSISTENCY H H H H H M L H M H H M PKB CONSISTENCY H H M M M H H M M H H H CKB CONSISTENCY H H H H M L M H M H H H AFTER 18Z THURSDAY... IFR IN CLOUDS POSSIBLE IN THE HIGHER ELEVATIONS OF THE MOUNTAINS WED NT INTO THU. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR WVZ005>011- 013>019-024>026. WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR WVZ020-027>032- 037>040-046-047. OH...WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR OHZ066-067-075- 076-083>087. KY...WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR KYZ101>103-105. VA...NONE. && $$ SYNOPSIS...TRM/JMV/MZ NEAR TERM...JMV SHORT TERM...TRM LONG TERM...MZ AVIATION...JMV

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