Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 090948 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 448 AM EST TUE FEB 9 2016 .SYNOPSIS... COLD AND UNSETTLED TODAY THROUGH WEDNESDAY UNDER A LARGE MID AND UPPER LEVEL LOW...WITH ROUNDS OF SNOW SHOWERS. ANOTHER ARCTIC FRONT BRINGS SNOW SHOWERS TO START THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... 445 AM UPDATE... GIVEN OBSERVED SNOWFALL AND NEW FCST AMOUNTS REMOVING SOME LOW NEAR TERM MODELS...NEW SNOW TOTALS NECESSITATE UPGRADE TO WARNING FOR MIDDLE OHIO VALLEY COUNTIES...IN CONCERT WITH THAT ALREADY UP UP STREAM...AND GOING UNTIL 6 PM TODAY. REST SAME. PREV DISCN... IMPRESSIVE EASTERN U.S. TROUGH OVER THE AREA EARLY THIS MORNING WITH H5 HEIGHT ANOMALIES 3 SD BELOW NORMAL OVER THE SERN U.S. INCLUDING THE FL PANHANDLE AND NRN GULF COAST. H85 TEMPERATURE ANOMALIES GET TO 3 SD BELOW NORMAL IN THAT AREA TONIGHT. AN ALMOST EQUALLY IMPRESSIVE WRN U.S. RIDGE WAS IN PLACE WITH HEIGHTS 2.5 SD ABOVE NORMAL OVER THE NRN ROCKIES. THIS SPELLS A COLD FCST TODAY AND TONIGHT WITH NUMEROUS SNOW SHOWERS AROUND BENEATH THE DEEP UPPER LEVEL LOW. THE ARCTIC FRONT WAS JUST MOVING NEWD THROUGH CENTRAL WV EARLY THIS MORNING...AND SHOULD GET THROUGH THE REMAINDER OF THE AREA FIRST THING THIS MORNING. GUSTY SNOW SHOWERS ACCOMPANY THE FRONT. THE WET SNOW LAST EVENING AND OVERNIGHT...AND THE SHARPLY LOWER TEMPERATURES EARLY THIS MORNING...WILL LEAD TO SLICK ROADS BENEATH THE SNOW THIS MORNING...PARTICULARLY WHERE NOT TREATED OR PRE-TREATED. THE OTHER NOTABLE FEATURE UNDER THE NOSE EARLY THIS MORNING IS A BAND OF SNOW ACROSS SRN OHIO ASSOCIATED WITH AN UPPER LEVEL S/W TROUGH PIVOTING AROUND AN UPPER LEVEL LOW OVER N-CENTRAL OHIO. ENHANCED BY REVERSE WARM ADVECTION FROM THE N...THIS BAND MAY PERSIST THROUGH MUCH OF THE DAY TODAY...CONTINUING TO PIVOT FOR A TIME BEFORE FINALLY DRIFTING E OF THE OHIO RIVER. OTHERWISE SNOW SHOWERS WILL BE MOST PERSISTENT IN AND JUST W OF THE MOUNTAINS GIVEN UPSLOPE FLOW...BUT DIURNAL HEATING BENEATH THE UPPER LOW WILL MAKE FOR AUTO CONVECTIVE SOUNDINGS IN THE LOWER LEVELS WHICH WILL ENHANCE SNOW SHOWERS ACROSS THE LOWLANDS AS WELL. USING A BLEND OF SHORT AND NEAR TERM MODELS TODAY AND SHORT TERM MODELS TONIGHT...OROGRAPHIC LIFT AND SNOW RATIOS DERIVED FROM DENDRITIC GROWTH...SNOW AMOUNTS STILL FALL TWO TO FIVE INCHES BELOW WARNING CRITERIA...THE LOW TWO INCH DIFFERENCE BEING IN AND NEAR OHIO...ASSOCIATED WITH THE BAND OF SNOW PIVOTING ABOUT THAT AREA TODAY. WILL NEED TO KEEP A KEEN EYE ON THAT SITUATION FOR POSSIBLE UPGRADE TO A WARNING AS IS ALREADY IN EFFECT UPSTREAM UNTIL NOON TODAY. ALSO USED A BLEND OF SHORT AND NEAR TERM MODELS FOR TEMPERATURES TODAY...AND THEN BLENDED IN BIAS CORRECTED VERSIONS OF THE MAV AND NAM FOR LOWS TONIGHT...SLIGHTLY LOWER VALUES ALL AROUND COMPARED WITH PREVIOUS. ALSO HAVE LOWER DEW POINTS...PARTICULARLY IN A DRY SWATH ACROSS ERN KY...SRN WV AND SW VA...FURTHER DIFFERENTIATING THE COVERAGE OF SNOW SHOWERS THERE TODAY...COMPARED WITH AREAS TO THE N. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY/... BROAD UPPER LEVEL TROUGH WILL CONTINUE TO AFFECT THE LOCAL AREA WEDNESDAY. THE LOW STARTS TO LIFT OUT OF THE AREA WED NT AND THU. A SERIES OF VORTICITY LOBES WILL ROTATE AROUND THE PERIPHERY OF THE TROUGH TO KEEP SOME FORCING FOR SNOW SHOWERS WEDNESDAY THROUGH THURSDAY. WESTERLY FLOW WEDNESDAY VEERS FROM THE NORTHWEST THURSDAY. NORTHWEST FLOW WILL SET THE PLUME OF MOISTURE FROM LAKE MICHIGAN RIGHT TOWARDS NORTH OF OUR AREA THURSDAY. IN ADDITION...NORTHWEST FLOW WILL PRODUCE UPSLOPE SNOW SHOWERS IN AND NEAR THE MOUNTAINS WEDNESDAY NIGHT INTO THURSDAY. CODED FROM ONE TO 2.4 INCHES OF SNOW RANGING FROM SOUTHEAST OH...EAST INTO THE EASTERN MOUNTAINS BY WEDNESDAY NIGHT. AN ADDITIONAL INCH OR SO EXPECTED OVER THE NORTHEAST MOUNTAINS THURSDAY. ANOTHER VORTICITY LOBE CROSSES THE AREA FRIDAY UNDER NORTHWEST FLOW ENHANCING SNOW OVER THE LOWLANDS...AND UPSLOPE SNOW OVER THE EASTERN MOUNTAINS FRIDAY INTO THE WEEKEND. USED THE SUPERBLEND FOR TEMPERATURES THROUGH THE PERIOD. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... SOME LINGERING SNOW SHOWERS ACROSS THE NORTHERN MOUNTAINOUS COUNTIES TO START THE PERIOD. THIS IS DUE TO NW FLOW ALOFT. HOWEVER...A SURFACE HIGH PRESSURE IS NOSING IN SO IT WILL BE A TIGHTROPE WALK BETWEEN NORTHWEST FLOW AND DEPARTING MOISTURE. SOME UNCERTAINTY ON POPS THIS WEEKEND...AS ECMWF SLIDES A SURFACE LOW TO OUR NORTH DRIVING A COLD FRONT THROUGH. HOWEVER...THE GFS IS MUSH LESS ROBUST WITH THIS SYSTEM...WITH A WEAKER FRONT AND LESS MOISTURE. STAYED IN CHANCE POPS FOR NOW. EITHER WAY...REINFORCING SHOT OF COLD AIR ARRIVES WITH THIS FRONT SETTING UP A VERY CHILLY WEEKEND. STILL BREEZY DURING THIS TIME AS THE NEXT HIGH PRESSURE DOES NOT NOSE IN UNTIL DURING THE DAY SUNDAY. WILL MENTION POTENTIAL FOR WIND CHILL ADVISORY IN THE HWO. MOST WIDESPREAD ISSUE LOOKS TO BE SATURDAY NIGHT...BUT SHOULD HIGH ARRIVE SOONER THAN FORECAST...WIND COULD SHUT DOWN EARLY. ANOTHER SYSTEM LOOKS TO IMPACT THE END OF THE PERIOD...BUT WITH FAIRLY DRASTIC DIFFERENCES IN THE MODELS STUCK CLOSE TO WPC FOR NOW. && .AVIATION /10Z TUESDAY THROUGH SATURDAY/... A SOMEWHAT LOW CONFIDENCE FCST DURING THE 24 HOUR TAF PERIOD DUE TO THE VARIABILITY OF CONDITIONS WITH NUMEROUS SNOW SHOWERS ABOUT. A VERY COLD AIR MASS OVERTAKES THE AREA OVERNIGHT...AS AN UPPER LEVEL LOW SETTLES IN OVER THE UPPER OHIO VALLEY. THIS WILL KEEP SNOW SHOWERS...AND ASSOCIATED IFR CONDITIONS...MOST FREQUENT ACROSS THE MIDDLE OHIO VALLEY AND NRN WV ALTHOUGH...BECAUSE THIS IS AN UPSLOPE PATTERN...FREQUENT MVFR CONDITIONS WITH IFR AT TIMES CAN BE EXPECTED DOWN THE WV MOUNTAINS. THIS LEAVES ERN KY AND SRN WV WITH VFR VSBY MUCH OF THE TIME...BUT ANY SNOW SHOWER OR BAND CAN BRING A BRIEF PERIOD OF IFR. EVEN THERE...MVFR CIGS WILL BE PERSISTENT...PERHAPS LIFTING TO MVFR AT TIMES TUE AFTERNOON. SFC FLOW WILL BE MAINLY FROM THE W...AND BE GUSTY AT TIMES...MAINLY DURING THE DAY ON TUE. HOWEVER...WINDS WERE GUSTY AT HTS AS OF 06Z...JUST BEHIND THE ARCTIC FRONT...AND BRIEF GUSTY WINDS ARE LIKELY TO PROGRESS NEWD ACROSS WV THROUGH EARLY TUE MORNING...AS THE ARCTIC FRONT MOVES FROM SW TO NE THROUGH THE STATE. FLOW ALOFT WILL BE LIGHT TO MODERATE W. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z WEDNESDAY... FORECAST CONFIDENCE...LOW ALTERNATE SCENARIOS: TIMING AND EXTENT OF IFR WILL VARY IN SNOW SHOWERS OVERNIGHT AND ESPECIALLY ON TUE. 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. DATE TUE 02/09/16 UTC 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21 EST 1HRLY 05 06 07 08 09 10 11 12 13 14 15 16 CRW CONSISTENCY M M M M M M M M M M M M HTS CONSISTENCY M M M M M M M H H H H M BKW CONSISTENCY M L L L M M M M M M M M EKN CONSISTENCY L L L L L L L L L L L L PKB CONSISTENCY L L L L L M M M M M M M CKB CONSISTENCY L L L L L L L L L L L L AFTER 12Z WEDNESDAY... PERIODS OF IFR CONDITIONS IN SNOW SHOWERS ALL THE WAY THROUGH WEDNESDAY NIGHT...ESPECIALLY NORTH AND EAST PORTIONS OF AREA. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...WINTER WEATHER ADVISORY UNTIL 7 AM EST WEDNESDAY FOR WVZ005>008-011-013>020-024>040-046-047. WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 7 AM EST WEDNESDAY FOR WVZ009-010. WINTER STORM WARNING UNTIL 6 PM EST THIS EVENING FOR WVZ009- 010. OH...WINTER WEATHER ADVISORY UNTIL 7 AM EST WEDNESDAY FOR OHZ083- 086-087. WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 7 AM EST WEDNESDAY FOR OHZ066-067-075-076-084-085. WINTER STORM WARNING UNTIL 6 PM EST THIS EVENING FOR OHZ066- 067-075-076-084-085. KY...WINTER WEATHER ADVISORY UNTIL 7 AM EST WEDNESDAY FOR KYZ101>103-105. VA...WINTER WEATHER ADVISORY UNTIL 7 AM EST WEDNESDAY FOR VAZ003- 004. && $$ SYNOPSIS...ARJ/TRM NEAR TERM...TRM SHORT TERM...ARJ LONG TERM...MZ AVIATION...TRM

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