Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 241827 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 125 PM EST WED DEC 24 2014 .SYNOPSIS... COLD FRONT BRINGS GUSTY WINDS AND SHOWERS THIS AFTERNOON. CHRISTMAS DAY STARTS COLD...CLOUDY...AND WINDY. HIGH PRESSURE CHRISTMAS NIGHT INTO FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... 11 AM UPDATE. SOME MINOR TIMING CHANGES...BUT OVERALL FORECAST ON TRACK. PREVIOUS DISCUSSION... SFC LOW TO DEVELOP AND TRACK NORTH OF THE TN VALLEY AND INTO MI TODAY. ACCOMPANYING COLD FRONT TO SWING THROUGH LATER THIS AFTERNOON AND THIS EVENING...REACHING OH RIVER BY AROUND 20Z AND EXITING EAST OF THE CWA AROUND 02Z. SOUNDING PROFILES INDICATE FAIRLY STABLE ATMOSPHERE OUT AHEAD OF FRONT AND TWEAKED POPS BACK FOR TODAY...PRIOR TO FRONT ARRIVAL. HOWEVER...INVOF FRONT THERE IS ENOUGH SHALLOW INSTABILITY AND PLENTY OF MOISTURE IN PLACE FOR LOW TOPPED SHOWERS WITH A FEW LIGHTNING STRIKES. BOTH GFS AND NAM12 SWING A 50-60KT 85H JET CORE NORTH ALONG THE OH RIVER WITH THE FRONT AND JUST BEHIND. ANY CONVECTION IN PLACE COULD EASILY SEE THESE WINDS BEING TRANSLATED TO SFC. BETWEEN THE MODELS...THE GFS IS TRENDING FASTER WITH PROGRESSION OF FRONT ACROSS THE CENTRAL APPALACHIANS AND THIS IS THE PREFERRED SOLUTION. COULD SEE BAROCLINIC BOUNDARY GETTING HUNG FOR A SHORT PERIOD ALONG THE EASTERN EXTENT OF THE CWA FOR A FEW HOURS THOUGH LATER THIS EVENING. EXPANDED WIND ADV FURTHER TO THE EAST TO COVER CKB THIS EVENING...MAINLY TO COVER RIDGETOPS AND WINDS WITH AND JUST BEHIND THE FRONT AS IT MAKES ITS WAY THROUGH. MAX TEMPS TODAY WILL BE WELL ABOVE NORMAL AHEAD OF THE FRONT WITH DEEP SOUTHERLY FLOW IN PLACE. TEMPS WILL DROP OFF DURING THE OVERNIGHT HOURS WITH CAA IN PLACE BRING A PERIOD OF WINTRY MIX BY CHRISTMAS MORNING. && .SHORT TERM /THURSDAY THROUGH SATURDAY/... MODELS CONTINUE TO SHOW THAT 850 MB TEMPERATURES BEHIND THE FRONT ARE MARGINAL FOR AUTO CONVECTION...ALTHOUGH PLENTY OF LOW LEVEL MOISTURE AND UPSLOPE WINDS EXIST. THEREFORE...WILL KEEP POPS IN THE CHANCE CATEGORY. HIGH PRESSURE BUILDS IN FOR THURSDAY NIGHT AND FRIDAY. LOTS OF SPREAD IN THE ARRIVAL OF THE NEXT SYSTEM OVER THE WEEKEND. THE GENERAL TREND IS SLOWER HOWEVER...SO WILL REMOVE POPS FOR FRIDAY NIGHT. && .LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/... HIGH PRESSURE EXITING TO THE EAST EARLY IN THE LONG TERM. MODELS THEN HAVE SOME DISCREPANCIES GOING FORWARD. ECMWF HAS HAD A STRETCH OF RATHER LACKLUSTER PERFORMANCE IN THE LONG TERM RECENTLY...SO WHILE NOT DISCOUNTING IT COMPLETELY...DID PUT MORE WEIGHT ON THE GFS WHILE BLENDING. THIS BRINGS A MOISTURE STARVED COLD FRONT THROUGH SATURDAY...AND THEN A SECOND SURFACE WAVE RIDES UP THE FRONT SUNDAY INTO MONDAY. GFS HAS THIS WELL SOUTH AND EAST OF CWA...WITH THE EASTERN THIRD OF THE CWA BEING CLIPPED BY THE NW FRINGE OF THE QPF FIELD. FOR COMPARISON...THE ECMWF IS MUCH FARTHER WEST WITH THE SECOND WAVE. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
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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.
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&& .RLX WATCHES/WARNINGS/ADVISORIES... WV...WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR WVZ005>011- 013>019-024>026. WIND ADVISORY FROM 5 PM THIS AFTERNOON TO 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...KMC NEAR TERM...KMC/JMV SHORT TERM...RPY LONG TERM...MZ AVIATION...KMC/JMV

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