Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 270257 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 957 PM EST THU FEB 26 2015 .SYNOPSIS... COLD AIR USHERS INTO THE REGION SQUEEZING A FEW SNOW SHOWERS OUT OVERNIGHT INTO EARLY FRIDAY. DRY ARCTIC HIGH PRESSURE FRIDAY INTO SATURDAY. CLIPPER LATE IN THE WEEKEND. ANOTHER LOW EARLY TO MID WEEK. && .NEAR TERM /THROUGH FRIDAY NIGHT/... AN INCH OR SO OF SNOW ACCUMULATION IN OUR CENTRAL WV MOUNTAIN COUNTIES OVERNIGHT AS THE AIR TURNS COLDER...AND BETTER CRYSTAL GROWTH TEMPERATURES ARRIVE. THE COLD IS THE MAIN STORY THE NEXT 36 HOURS...AS WINDCHILLS DIP TO NEAR 0 F IN THE LOWLANDS. LUCKILY WINDS DIE OFF BY FRIDAY EVENING WHEN THE COLDEST TEMPERATURES OF THIS AIR MASS ARRIVE. THE FORECASTED TEMPERATURES ARE ABOVE WHAT OCCURRED JUST LAST WEEK...BUT STILL WELL BELOW NORMAL FOR EVEN THE DEAD OF WINTER. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... ARCTIC HIGH PRESSURE OVER THE MS...OH VALLEYS EXTENDS INTO WV FRIDAY NIGHT INTO SATURDAY. MODELS IN AGREEMENT WITH H85 TEMPERATURES AROUND MINUS 17C FRIDAY NIGHT...GRADUALLY WARMING UP TO MINUS 5C BY 00Z SUNDAY. MOSTLY CLEAR SKIES AND AREAS OF SNOW COVER WILL ALLOW RADIATIONAL COOLING TO TAKE PLACE PROVIDING VERY COLD TEMPERATURES FRIDAY NIGHT...GENERALLY IN THE SINGLE DIGITS LOWLANDS...RANGING TO A DEGREE OR TWO BELOW ACROSS PORTIONS OF SOUTHEAST OH AND THE WV NORTHEAST MOUNTAINS. PERIODS OF SUNSHINE ARE ANTICIPATED SATURDAY. FLOW AT H50 BECOMES ZONAL SATURDAY. HOWEVER...A WEAK SHORT WAVE RIDES EAST ALONG THE ZONAL FLOW CROSSING THE AREA SATURDAY INTO SATURDAY NIGHT. MODELS ARE IN FAIR AGREEMENT IN THEIR QPF FIELDS SPREADING PCPN FROM NORTHWEST TO SOUTHEAST...WITH THE FASTER NAM BY LATE SATURDAY NIGHT ACROSS THE EXTREME NORTH AND SOUTHERN SECTIONS...WHILE THE GFS AND ECMWF DELAY THE ONSET OF PCPN BY SUNDAY THROUGH MONDAY. PER MODEL CONSENSUS...KEPT LIKELY AND CATEGORICAL POPS CLOSER TO THE ECMWF AND GFS SOLUTIONS FOR SUNDAY. FLOW AT H850 BECOMES SOUTH TO SOUTHWEST BRINGING MORE WARM ADVECTION WITH TEMPS REACHING MINUS 5C TO 0C SUGGESTING PCPN COULD FALL IN THE FORM OF LIQUID OR MIXED WITH SNOW OR SLEET. WENT WITH THE BIAS CORRECTED CONSENSUS MOS AND ALL BLEND FOR TEMPERATURES THROUGH THE PERIOD. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... ACTIVE WEATHER PATTERN IN THE LONG TERM...WITH LOTS OF UNCERTAINTY IN THE DETAILS. FRONTAL BOUNDARY SOUTH OF THE CWA AT THE BEGINNING OF THE PERIOD...WITH HIGH PRESSURE BUILDING IN BRIEFLY FROM THE NORTH. HOWEVER...THIS WILL BE SHORT LIVED AS ANOTHER LOW WILL MOVE EAST OUT OF THE PLAINS TOWARDS THE REGION. THERE COULD BE A BRIEF PERIOD OF SLEET OR FREEZING RAIN EARLY TUESDAY MORNING AT THE ONSET OF PRECIPITATION...BEFORE ENOUGH WARM AIR IS ABLE TO SCOUR OUT ANY COLD AIR NEAR THE SURFACE. WITH A GOOD SOUTHWESTERLY FLOW DEVELOPING...EXPECTING A CHANGE OVER TO RAIN BY TUESDAY AFTERNOON...EVEN ACROSS THE MOUNTAINS. AS MENTIONED IN PREVIOUS DISCUSSIONS...THERE WILL BE A GOOD TAP OF GULF MOISTURE...AND THERE IS THE POTENTIAL FOR A SECONDARY LOW TO RIDE UP OUT OF THE GULF INTO THE SOUTHEASTERN U.S. MID TO LATE WEEK...BUT MODELS ARE NOT IN GOOD AGREEMENT IN THE PATH/MOISTURE SPREAD ASSOCIATED WITH THIS FEATURE AT THIS TIME. SO...POINT IS...WITH AT LEAST 1 FEATURE EXPECTED EARLY NEXT WEEK...WITH THE POTENTIAL FOR HEAVY RAIN...AND A DECENT SNOW PACK IN PLACE IN SOME LOCATIONS...PARTICULARLY SOME OF THE MOUNTAINOUS LOCATIONS...WATER ISSUES ARE POSSIBLE. PARTICULARLY...IF THE SECONDARY FEATURE WOULD HAPPEN TO DEVELOP...AND SPREAD A SECONDARY ROUND OF PRECIPITATION ACROSS PARTS OF THE AREA LATE WEEK AFTER THE INITIAL SHOT. HOWEVER...ANOTHER ISSUE WITH THE SECONDARY FEATURE IS THAT BASED ON THE PATH...COULD EVEN SEE PERIODS OF SNOW...NOT JUST RAIN. SO...LOTS OF UNCERTAINTY IN AMOUNT/RATE OF SNOW MELT...AND EVEN IN PRECIPITATION AMOUNTS AND TYPES AT TIMES NEXT WEEK. SO...IN A NUTSHELL...WILL GO AHEAD AND HIGHLIGHT THE RISK FOR POTENTIAL FLOODING NEXT WEEK IN THE HWO...AS FEEL THERE IS AT LEAST SOME RISK WITH THE FIRST FEATURE EARLY/MID WEEK. && .AVIATION /03Z FRIDAY THROUGH TUESDAY/... MVFR CEILINGS SHOULD REFORM 03Z TO 06Z ESPECIALLY IN WEST VIRGINIA. SOME MVFR VSBY IN SCATTERED SNOW SHOWERS MOSTLY 04Z TO 14Z. MOSTLY VFR AFTER 14Z FRIDAY IN SCATTERED CLOUDS. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SATURDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: LESS STRATOCUMULUS CEILINGS THAN EXPECTED ARE POSSIBLE IN THE COLDER BUT DRIER ARCTIC AIR LATE TONIGHT INTO EARLY FRIDAY. ALSO THE EXTENT IN WHICH THE SNOW SHOWERS IMPACT TAF SITES MAY DIFFER...TOOK THE PESSIMISTIC APPROACH FOR THE MTN SITES. 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 FRI 02/27/15 UTC 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13 EST 1HRLY 21 22 23 00 01 02 03 04 05 06 07 08 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H H H H H H M H H M BKW CONSISTENCY M M M M L H H H H H H H EKN CONSISTENCY M L L L L L M M M M H M PKB CONSISTENCY H H H H H M H H H M M M CKB CONSISTENCY H M M M M M H H H H H H AFTER 00Z SATURDAY... IFR POSSIBLE IN RAIN OR MIXED RAIN/SNOW SUNDAY INTO MONDAY. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...ARJ/SL/JW NEAR TERM...JW SHORT TERM...ARJ LONG TERM...SL AVIATION...JW

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