Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 251944 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 244 PM EST WED FEB 25 2015 .SYNOPSIS... LOW PRESSURE SYSTEM PASSES TO OUR SOUTHEAST LATE TONIGHT. COLD FRONT WITH SNOW SHOWERS LATE THURSDAY/THURSDAY NIGHT. DRY ARCTIC HIGH PRESSURE FRIDAY. CLIPPER LATE IN THE WEEKEND. && .NEAR TERM /THROUGH THURSDAY/... QUICK HITTING STORM BRUSHES CWA OVERNIGHT. BEST SUPPORT ALOFT FROM COUPLED 250 MB JET IS AT 00Z TONIGHT...HELPING TO QUICKLY MOISTEN THE COLUMN TO OUR SOUTH AND THUS THICKEN THE CLOUDS OVER SOUTHERN COUNTIES. OF COURSE...EXACTLY HOW FAR NORTH THE FLAKES REACH THE GROUND IS ALWAYS A CHALLENGE. DURATION OF THE DEEPER MOISTURE IS ONLY 6 TO 12 HOURS...AND SOUNDINGS NOT THE MOST FAVORABLE...A BIT ON THE MILD SIDE...FOR BEST CRYSTAL GROWTH. WILL HAVE THE MAIN POP GRADIENT RUNNING FROM NEAR LOUISA NORTHEAST TO CHARLESTON AND PHILLIPI...WITH MUCH HIGHER TO THE E-SE...LOWER TO THE W-NW. AS CEILINGS CRASH OVER THE SOUTHERN MOUNTAINS NEAR BKW IN THE SNOW...THE WEAK SE FLOW MAY HOLD CLOUDS HIGHER VCNTY CRW. SO ALL IN ALL...STILL NO WARNINGS. WILL EXPAND OUR EXISTING WINTER WEATHER ADVISORY JUST A BIT...MAINLY FOR 1 TO 3 INCHES OF SNOW OVERNIGHT INTO THURSDAY MORNING. THE MILDER BOUNDARY LAYER TEMPERATURES MAY RESULT IN THE MORE TYPICAL SNOW VARIATION BETWEEN RIVER VALLEY AND HIGH TERRAIN ACROSS THESE SOUTHERN COAL FIELDS. CONFIDENCE LOWERS ON HOW THE DAY UNFOLDS ON THURSDAY. WITH THINKING A LOT OF CLOUDS WILL LINGER OVER THE MOUNTAINS...AFTER SATURATING OVERNIGHT. STILL TRYING TO PAINT A BREAK IN POPS OVER THE OHIO VALLEY THURSDAY MORNING...BEFORE INCREASING AGAIN THURSDAY AFTERNOON WITH THE WEAKENING NORTHERN STREAM FEATURE. SO NOT FORESEE MUCH OF A TEMPERATURE DROP OVERNIGHT WITH THE PREVIOUSLY MENTIONED THICKENING CLOUDS. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... HIGH PRESSURE BUILDS ACROSS THE OH VALLEY...WV AND PA SATURDAY. HOWEVER...MODELS SUGGEST LINGERING MOISTURE WITHIN THE DENDRITE GROWTH ZONE ACROSS CENTRAL WV AND EAST THURSDAY NIGHT. THIS SUGGEST A CONTINUATION OF LIGHT SNOW SHOWERS THURSDAY NIGHT. AS THE FLOW TURNS NORTHWEST...LINGERING MOISTURE COULD STILL PRODUCE UPSLOPE SNOW MAINLY OVER OUR NORTHEAST MOUNTAINS INTO FRIDAY. INCREASED POPS HIGHER THAN 50 PERCENT...OR LIKELIES TO ACCOUNT FOR MINOR SNOW ACCUMULATIONS OVER PORTIONS OF THE LOWLANDS AND EASTERN MOUNTAINS THROUGH FRIDAY. ALL PCPN SHOULD MOVE OUT BY FRIDAY NIGHT. WEATHER IMPROVES FRIDAY INTO FRIDAY NIGHT WITH COLDER AIR RUSHING IN AS SEEN ON MODELS H850 TEMPERATURES REACHING MINUS 17C. THIS COULD BRING A NON DIURNAL TREND IN TEMPERATURES FRIDAY WITH HIGHS STAYING AROUND 20F RANGING INTO THE SINGLE DIGITS OVER THE HIGHEST PEAKS. AND LOWS FRIDAY NIGHT INTO THE LOWER SINGLE DIGITS EXTREME SOUTH RANGING INTO AROUND ZERO AND FEW DEGREES BELOW FURTHER NORTH. USED THE BIAS CORRECTED ALL BLEND FOR TEMPERATURES THROUGH THE PERIOD. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... HIGH PRESSURE TO START THE PERIOD. HOWEVER...CLIPPER TYPE SYSTEM WILL MOVE THROUGH AREA SUNDAY THROUGH MONDAY...FOLLOWED BY ANOTHER LOW THAT WILL MOVE NORTHEAST OUT OF THE GULF TOWARDS THE REGION MID WEEK. FIRST CLIPPER SYSTEM WILL SEE MAINLY RAIN TO START...BUT TRANSITION OVER TO LIGHT SNOW SUNDAY NIGHT AS COLDER AIR RUSHES IN BEHIND THE FRONT. STILL LOOKING LIKE THE MID WEEK LOW WILL MOVE ACROSS OUR NORTH THROUGH OHIO. WARM AIR AND MOISTURE WILL SURGE INTO THE REGION OUT AHEAD OF THE LOW...WITH STRONG SOUTHWESTERLY FLOW DEVELOPING...AND PW VALUES RISING TO WELL ABOVE NORMAL FOR THIS TIME OF YEAR. THIS WILL BE A MAINLY RAIN SYSTEM...WITH THE POSSIBILITY RAIN COULD BE HEAVY AT TIMES. BASED ON THE PATH OF THE LOW...COULD SEE A BRIEF DRY SLOT DEVELOP ACROSS PARTS OF THE WV LOWLANDS...BUT TOO EARLY TO FIGURE THAT IN AT THIS POINT. WITH THE RAIN...COULD BE SOME LOCALIZED WATER ISSUES NEXT WEEK. WILL CONTINUE TO LEAVE OUT OF THE HWO AT THIS TIME...AS IT IS SEVERAL DAYS UNTIL THE EVENT...AND ANYTHING COULD HAPPEN IN THE MODEL RUNS UNTIL THEN...THUS CHANGING THE FORECAST. && .AVIATION /20Z WEDNESDAY THROUGH MONDAY/... VFR INTO THE EVENING. THICKENING MID LEVEL CLOUDS AT 8 TO 12 THSD FT AGL FROM SOUTHWEST TO NORTHEAST 00Z TO 06Z...WITH LIGHT SNOW DEVELOPING LNP TO BKW CORRIDOR DURING THE 03Z TO 06Z TIME FRAME. DETERIORATING CONDITIONS MOSTLY OVER MOUNTAIN COUNTIES WITH WEAK SE FLOW. TRIED TO HOLD CEILINGS HIGHER VCNTY OF CRW DESPITE FORECASTING LIGHT SNOW DURING THE 06Z TO 12Z TIME FRAME. CONFIDENCE LOWERS IN WAKE OF THE DEEPER MOISTURE FOR THE 12Z TO 18Z FRAME ON THURSDAY. TRIED TO HOLD ONTO SOME LOW CEILINGS AND SOME 3 TO 5 MILES IN FOG/LINGERING LIGHT SNOW OVER THE MOUNTAINS IN WAKE OF THE MAIN SNOW BAND. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z THURSDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING OF SNOW REACHING THE GROUND MAY VARY..AND HOW FAR WEST/NORTHWEST IT REACHES THE GROUND. 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 20 21 22 23 00 01 02 03 04 05 06 07 EST 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02 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 M BKW CONSISTENCY H H H H H H H H H M M M 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 18Z THURSDAY... IFR POSSIBLE IN SNOW SHOWERS MAINLY OVER WV MOUNTAIN COUNTIES INTO THURSDAY NIGHT. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 9 AM EST THURSDAY FOR WVZ033>036. WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST THURSDAY FOR WVZ024-025. OH...NONE. KY...NONE. VA...WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 7 AM EST THURSDAY FOR VAZ003-004. && $$ SYNOPSIS...KTB/ARJ/SL NEAR TERM...KTB SHORT TERM...ARJ LONG TERM...SL AVIATION...KTB

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