Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 061046 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 546 AM EST SAT FEB 6 2016 .SYNOPSIS... HIGH PRESSURE BUILDS INTO SUNDAY...WITH A TRANQUIL FEBRUARY ENVIRONMENT. COLD FRONT MONDAY. UNSETTLED/COLDER TUESDAY AND WEDNESDAY UNDER MID/UPPER LEVEL LOW...WITH ROUNDS OF SNOW SHOWERS. && .NEAR TERM /THROUGH TONIGHT/... A SFC HIGH PRESSURE REMAINS IN CONTROL WITH DRY AND COOL WEATHER. SATELLITE IMAGES AND SFC OBS SHOW HIGH LEVEL CLOUDS MOVING NORTHEAST ACROSS THE AREA. EXPECT THESE CLOUDS TO CONTINUE COVERING THE SKIES THROUGH TONIGHT. TEMPERATURES WILL BE NEAR NORMAL. GENERALLY IN THE MID 40S LOWLANDS TO UPPER 30S HIGHEST ELEVATIONS FOR HIGHS. LOWS WILL DEPEND ON CLOUD COVER TONIGHT. SINCE EXPECTING MOSTLY CLEAR SKIES...LIGHT AND VARIABLE TO CALM WINDS AFTER THE LOWER ATMOSPHERE DECOUPLES...TEMPERATURES WILL DROP INTO THE MID TO UPPER 20S. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... SIGNIFICANT CHANGES IN AIRMASS AND PRECIPITATION CHARACTERIZE THE SHORT TERM FORECAST WITH A WELL ADVERTISED UPPER LEVEL LOW DIVING INTO THE SOUTHERN GREAT LAKES FROM THE UPPER MISSISSIPPI VALLEY. SINCE THE OPERATIONAL NAM/GFS/ECMWF ARE IN FAIRLY GOOD AGREEMENT...RELIED ON THE NAM FOR THE DETAILS FOR THE UPPER LEVEL SYSTEM AND THE SURFACE SYSTEM COUNTERPART AS THEY TRAVERSE THE OHIO VALLEY/CENTRAL APPALACHIANS. INITIAL BAND OF SHOWERS EXPECTED WITH THE FRONT...AND ONCE AGAIN...HAVE USED LOW TO MID LEVEL DEFORMATION TO TIME THE ARRIVAL AND PASSAGE OF THIS FEATURE. EXPECTING A SLIVER OF DRY AIR BEHIND THE COLD FRONT...AND TRIED TO REPRESENT THIS IN A MARKED DECREASE IN CLOUD COVER AND DROPPING POPS TO SLIGHT CHANCE. TIMING OF THIS IS ALWAYS TRICKY...HOWEVER. SHOULD BE COMPLETELY RESATURATED IN THE LOWER LEVELS ACROSS THE ENTIRE CWA BY 06Z TUESDAY IN THE COLD AIR ADVECTION. HAVE SNOW CHANCES INCREASING EARLY MONDAY NIGHT INTO THE LIKELY/CATEGORICAL THROUGH MUCH OF TUESDAY...BUT THIS IS MORE OF AN AUTOCONVECTIVE SCENARIO AS OPPOSED TO AN UPSLOPE CONDITION DUE TO THE 1000-850MB STREAMLINES THAT ARE MORE WESTERLY THAN NORTHWESTERLY/PERPENDICULAR TO THE MOUNTAINS. NOT DISCOUNTING THE TERRAIN INFLUENCES COMPLETELY THOUGH. 850MB TEMPERATURES DROP INTO THE LOWER MINUS TEENS MONDAY NIGHT THROUGH TUESDAY. DUE TO THE TIMING...EXPECT VERY LITTLE TEMPERATURE RECOVERY MONDAY WITH THE FRONTAL PASSAGE DURING THE DAY. ALSO...HAVE TAKEN THE MAX TEMPERATURES FOR TUESDAY DOWN FROM THE GUIDANCE NUMBERS A FEW NOTCHES...WITH THE THINKING THAT ABOVE FREEZING VALUES WILL NOT BE A GOOD PLAY HERE. GUIDANCE TENDS TO OVERPLAY THESE SITUATIONS AND HAVE THE AREA TOO WARM...SO WILL KEEP IT COLD AREA WIDE. FOR AMOUNTS...NOT TOO MANY CHANGES IN SNOW FROM THE PREVIOUS FORECAST. DESPITE IT NOT BEING A PERFECT UPSLOPE SITUATION AS PREVIOUSLY MENTIONED...THINK THERE WILL BE BETTER ENHANCEMENT OF THE SNOWFALL IN THE HIGHER ELEVATIONS. BUT FOR THE MOST PART...THIS WILL BE A SLOW ACCUMULATION OF SNOW OVER TIME IN OFF AND ON SNOW SHOWERS AND SQUALLS OVER THE LOWLANDS. AS FAR AS FUTURE HEADLINE CONSIDERATIONS GOES...A LOT WILL DEPEND ON DURATION/HOW LONG IT TAKES TO GET THE ACCUMULATIONS...WHICH AS OF RIGHT NOW...SPANS WELL INTO DOUBLE DIGIT HOURS. HWO WILL BE HIGHLIGHTED AS SUCH. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... AFTER THE INITIAL SUPPORT SWINGS THROUGH ON MONDAY...POPS INCREASE AGAIN MONDAY NIGHT...WITH UPPER/MID LEVEL LOW DROPPING INTO OHIO AND SURFACE LOW TRYING TO TAKE SHAPE TOWARD DELMARVA. GFS AND ECMWF SIMILAR NOW...WITH 500 MID LEVEL LOW IN OUR VCNTY AROUND 18Z TUESDAY. OLD SOLUTIONS OVER THE PAST FEW DAYS...OF MID LEVEL LOW GOING TO OUR SOUTH...SEEMS LESS LIKELY NOW. WEAKENING 500 MB TROF REMAINS IN VICINITY INTO WEDNESDAY...WITH THE COLDER 850 MB TEMPS STILL ADVECTING IN ON WEDNESDAY. HAVE MIN TEMPS NEAR ZERO AOB 4 THSD FT WEDNESDAY NIGHT. ONLY APPARENT TEMPS AT WIND CHILL ADVISORY ALSO MOSTLY AOA 4 THSD FT. SO NOT WORTH HIGHLIGHTING IN THE HAZARDOUS WEATHER POTENTIAL. ROUNDS OF SNOW SHOWERS STILL EXPECTED MONDAY NIGHT INTO WEDNESDAY. ALSO STILL TRIED TO KEEP OUR POPS HIGHER THAN GUIDANCE IN THE MOIST LOW LEVEL THERMAL TROF AND MOISTURE DEPTH STILL UP TO 10 THSD FT. PICTURING AT THIS DISTANCE IN TIME...A LOT OF 1 TO 3 INCHES OF SNOW IN LOWLANDS OVER 12 HOURS...AND 2 TO 4 INCHES OVR MOUNTAIN COUNTIES MONDAY NIGHT INTO TUESDAY NIGHT. SO THINKING MORE TOWARD WINTER WEATHER ADVISORIES THAN TAKING THE WINTER STORM WATCH/WARNING AVENUE. OF COURSE...OVER 48 HOURS AMOUNTS WILL ADD UP OVER THE MOUNTAINS. WILL INCLUDE IN HAZARDOUS WEATHER POTENTIAL. LOW CONFIDENCE FOR DAY 6 AND 7...IN THE 100+ KNOT 250 MB FLOW FROM THE WEST NORTHWEST. COULD EASILY SEE SOME CLIPPER ACTION...BUT UNCERTAINTY IS IN THE TIMING. INCLUDED 20 POPS FOR NOW FOR THURSDAY NIGHT AND FRIDAY. && .AVIATION /10Z SATURDAY THROUGH WEDNESDAY/... SFC HIGH PRESSURE WILL PROVIDE DRY WEATHER...WITH LIGHT SOUTHERLY WINDS THROUGH THE PERIOD. DESPITE OF A DRY ATMOSPHERE...HIGH CIRRUS CLOUDS WILL BE COMMON SATURDAY. VFR CONDITIONS WILL PREVAIL AS A SFC HIGH PRESSURE REMAINS IN CONTROL THROUGH SATURDAY NIGHT. BUFKIT SOUNDINGS AND SFC OBS SHOW A VERY DRY ATMOSPHERE IN THE BOUNDARY LAYER. SFC FLOW WILL BE LIGHT MAINLY SW TODAY. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z SUNDAY... FORECAST CONFIDENCE...HIGH. ALTERNATE SCENARIOS: NONE. 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 SAT 02/06/16 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 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 H BKW CONSISTENCY H H H H H H H H H H H H 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 12Z SUNDAY... MVFR TO IFR CONDITIONS POSSIBLE IN RAIN/SNOW SHOWERS MONDAY INTO WEDNESDAY MORNING. && .HYDROLOGY... THE RIVER GAUGE AT PARKERSBURG...ALONG THE OHIO RIVER...HAS BEEN FIXED. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...ARJ/26 NEAR TERM...ARJ SHORT TERM...26 LONG TERM...KTB AVIATION...ARJ HYDROLOGY...

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