Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 242155 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 455 PM EST MON NOV 24 2014 .SYNOPSIS...
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WINDS DIMINISH TONIGHT AS STRONG LOW PRESSURE MOVES AWAY. HIGH PRESSURE TUESDAY. LOW PRESSURE MOVING UP THE EAST COAST WEDNESDAY BRINGS SNOW TO THE APPALACHIANS. WEAKER SYSTEMS UNTIL EARLY FRIDAY.
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&& .NEAR TERM /THROUGH TUESDAY/...
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MESOSCALE UPDATE... CORE OF LLJ CURRENTLY SLIDING THRU NE OH. SURFACE FRONT MAKING ITS WAY THRU E OH AND N KY AS OF 18Z. STILL LOOKING AT ABOUT A 3 HR WINDOW...BEGINNING NOW /18Z/...FOR ADV CRITERIA GUSTS ACROSS CWA AHEAD OF AND ALONG THE FRONT. THIS IS SUPPORTED BY VARIOUS MODEL SOUNDINGS WHICH SHOW GOOD MOMENTUM TRANSFER AIDED BY DRY LOW LEVELS. NUMEROUS ASOS AND AWOS SITES ACROSS THE AREA HAVE REPORTED 50 TO 55 MPH GUSTS IN THE PAST HR. THE GUSTS SHOULD DIMINISH AFTER 21Z AND PROBABLY WILL BE ABLE TO NIX THE ADV SOONER THAN CURRENT EXPIRATION OF 00Z. LOWERED POPS THIS AFTERNOON PER RADAR TRENDS. ATMOSPHERE IS JUST TOO DRY IN THE LOW LEVELS. REGION NEVER GETS INTO MUCH OF WIND SHIFT ALOFT AS TROF LIFTS OUT OF OH VALLEY. SO A GLANCING BLOW OF GOOD CAA. AS SUCH...THINK ANY POST FRONTAL STRATUS WILL BE CONFINED TO SE OH AND N WV. WINDS WILL SLACKEN A GOOD BIT OVERNIGHT...BUT STILL WILL HAVE A BL PUFF TO KEEP LOWS UP A BIT. TUESDAY WILL FEATURE SOME SUNSHINE WITH SOME INCREASING CLOUDS OVER THE MOUNTAIN IN THE AFTERNOON. TEMPS WILL BE SEASONABLY COOL.
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&& .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
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MODELS ARE IN BETTER AGREEMENT ON EAST COAST STORM ON WEDNESDAY. PER COORD WITH WWD AND NEIGHBORS...ISSUED WINTER STORM WATCH FOR POCAHONTAS AND RANDOLPH COUNTIES FOR THE POSSIBILITY OF SIX INCHES ACCUMULATION. THIS IS AN ELEVATION BASED EVENT...SO THE LARGEST ACCUMULATIONS WILL BE OVER THE HIGHER TERRAIN. THE STORM DEVELOPS AS TRANSITORY L/W TROUGHING SETS UP OVER THE ERN CONUS. WITHIN THE LARGER TROUGH...THE INDIVIDUAL S/W/S NEVER PHASE. HOWEVER...LIKE A PATIENT HITTER...THE SECOND S/W TROUGH STAYS BACK LONG ENOUGH FOR THE LEAD SYSTEM TO IMPACT AREAS AS FAR W AS THE CENTRAL APPALACHIANS. THE LOW CENTER TAKES THE CLASSIC TRACK NEWD UP THE CAROLINA COAST TUE NT...AND THEN FROM JUST S OF HATTERAS WED MORNING TO S OF CAPE CODE WED EVENING...SO THE MAIN EVEN IS WED STARTING EARLY IN THE MORNING. MODEL SOUNDINGS AND MOS GUIDANCE SUGGEST A FREEZING LEVEL OF 1500-2000 FT MSL...SO THE LOWLANDS AND THE LOWER MOUNTAIN VALLEYS WILL HAVE TEMPERATURES JUST ABOVE FREEZING. THE HIGHEST TERRAIN WILL HAVE TEMPERATURES AS LOW AS THE MID 20S...LOW ENOUGH FOR IMPACTFUL SNOW ACCUMULATIONS ON UNTREATED SURFACES. WITH DECENT MODEL CONSENSUS...USED A BLEND OF THE NAM...GFS...CMC AND ECMWF...AS WELL AS WPC...FOR QPF...CROSS-CHECKED WITH THE POPS. GIVEN WE ARE NOT DEALING WITH A WARM LAYER ALOFT...AND BOTH CRYSTAL PRESENCE AND GROWTH LOOK GOOD...SNOWFALL IS A FUNCTION MAINLY OF SFC TEMPERATURE AND QPF. HAVE COUNTY AVERAGES OF THREE INCHES WITH PEAK AMOUNTS JUST OVER 5 INCHES IN THE WATCH AREA. THE WINTER STORM WATCH IS BASED ON A 50% CONFIDENCE OF SIX INCHES FOR THE HIGHER TERRAIN WITHIN THE WATCH AREA AND COVERING AT LEAST HALF THE COUNTY ON THE BUSIEST TRAVEL DAY OF THE YEAR. THE WATCH IS ALSO ON THE UPSTREAM END OF WATCHES EXTENDING ALL THE WAY UP THROUGH NEW ENGLAND FOR THIS EVENT...MAKING AN EARLY DECISION ALL THE MORE PRUDENT. BLENDED IN NAM MODEL AND MOS FOR TEMPERATURES WHICH DID NOT ENTAIL MUCH CHANGE FROM THE PREVIOUS FCST FOR THE ALL-IMPORTANT EVENT TUE NT AND WED. HAVE WED NT A LITTLE COLDER THAN PREVIOUS GIVEN GUIDANCE CONSENSUS IN THAT DIRECTION...BLENDED IN THE BIAS CORRECTED MET. AVERAGED IN A CONSENSUS BLEND FOR HIGHS THU FOR LITTLE CHANGE FROM THE PREVIOUS FCST.
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&& .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... USED A BLEND OF THE ECMWF AND NAEFS MEAN FOR THE FORECAST. THIS ALLOWS FOR SOME UPSLOPE SNOW THURSDAY NIGHT...SO WILL INCREASE POPS THURSDAY EVENING. WARM ADVECTION THEN TAKES OVER FOR FRIDAY AND SATURDAY. NEXT FRONTAL BOUNDARY PUSHES INTO THE REGION ON SUNDAY. CONFIDENCE REMAINS LOW ON WHAT HAPPENS WITH THIS BOUNDARY ON MONDAY...SO FOR NOW WILL KEEP SOME LOW POPS AS IT COULD HANG OVER THE AREA. && .AVIATION /21Z MONDAY THROUGH SATURDAY/...
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VFR CONDITIONS WILL PREVAIL FOR MOST DURING THE TAF PERIOD. A COLD FRONT WILL PUSH THRU THIS AFTERNOON WITH LITTLE FANFARE IN TERMS OF PRECIP. CIGS WILL BE HARD PRESSED TO LOWER INTO MVFR STRATUS OVERNIGHT...BUT DID ALLOW FOR A FEW HOURS AT CKB/EKN. EXPECT JUST AN INCREASE IN MID LEVEL CLOUDS TUESDAY AFTERNOON ACROSS THE MOUNTAINS. CONCERNING WINDS...THE STRONG LOW LEVEL JET WILL CONT TO TRACK AWAY FROM THE AREA THIS AFTERNOON...THRU NE OH. HOWEVER...WITH THE DRY LOW LEVELS AND THE APPROACHING FRONT...THERE WILL CONTINUE TO BE EFFICIENT MIXING OF THE WINDS ALOFT THRU 21Z. OCCASIONAL WIND GUSTS 40 TO 45 KTS OUT OF SW ARE EXPECTED FOR ALL TERMINALS...WITH SUSTAINED WINDS GENERALLY 20 TO 30 MPH. THESE WINDS WILL SLACKEN CONSIDERABLY AFTER 21Z...AS THE FRONT CLEARS AND THE WINDS ALOFT DIMINISH. THERE ISNT EXPECTED TO BE MUCH OF A WIND SHIFT WITH FROPA...PERHAPS TURNING MORE TOWARD W THIS EVENING. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: THE STRONG GUSTY WINDS MAY LINGER A LITTLE WHILE LONGER THAN ANTICIPATED. 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 M 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 M M M M M H PKB CONSISTENCY H H H H H M M M M H H H CKB CONSISTENCY H H H H H H M M M M H H AFTER 18Z TUESDAY... IFR CONDITIONS IN SNOW IS POSSIBLE OVER THE MOUNTAINS ON WEDNESDAY...AND AGAIN THURSDAY NIGHT.
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&& .RLX WATCHES/WARNINGS/ADVISORIES...
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WV...WIND ADVISORY UNTIL 8 PM EST THIS EVENING FOR WVZ005>011- 013>020-024>040-046-047. WINTER STORM WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY AFTERNOON FOR WVZ046-047. OH...WIND ADVISORY UNTIL 8 PM EST THIS EVENING FOR OHZ066-067-075- 076-083>087. KY...WIND ADVISORY UNTIL 8 PM EST THIS EVENING FOR KYZ101>103-105. VA...WIND ADVISORY UNTIL 8 PM EST THIS EVENING FOR VAZ003-004.
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&& $$ SYNOPSIS...TRM NEAR TERM...30 SHORT TERM...TRM LONG TERM...RPY AVIATION...30

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