Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 261746 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 1246 PM EST MON JAN 26 2015 .SYNOPSIS... LOW PRESSURE SYSTEM MOVES OFF TO THE EAST TODAY. COLDER AIR MOVES IN LATE TODAY INTO TUESDAY. HIGH PRESSURE WEDNESDAY. LOW PRESSURE THURSDAY. && .NEAR TERM /THROUGH TONIGHT/... UPDATE... SNOW BAND HAS CROSSED THE OHIO RIVER INTO WEST VIRGINIA. REWORKING THE TEMPERATURES BASED ON CURRENT TRENDS...AND LARGELY USING THE RAP FOR THE NEXT FEW HOURS THROUGH 00Z. WILL BE WORKING ON SOME FORECAST SNOW TOTALS AS WELL AS THIS TRANSITIONS TO AN UPSLOPE EVENT LATER TODAY. PREVIOUS DISCUSSION... MODELS SHOWING COLD AIR GRADUALLY MOVING INTO THE REGION TODAY CHANGING THE PRECIPITATION FROM RAIN TO SNOW. MODELS ARE ALSO SHOWING SOME GOOD LIFT IN AN EASTWARD PROPAGATING BAND BEHIND THE CHANGE OVER TO SNOW...ALLOWING FOR SOME LIGHT SNOW ACCUMULATIONS TODAY...ESPECIALLY OVER CENTRAL AND NORTHERN PORTIONS OF THE FORECAST AREA. WILL CONTINUE THE WINTER WEATHER ADVISORY FOR PERRY COUNTY AS THAT AREA HAS ALREADY CHANGED TO SNOW AND SHOULD RECEIVE THE MOST ACCUMULATIONS THIS MORNING. LOW LEVEL COLD AIR MOVES IN LATE TODAY AND TONIGHT...CAUSING OVER TURNING IN THE LOWER ATMOSPHERE. THIS COMBINED WITH UPSLOPE SHOULD CREATE SOME LIGHT SNOW FOR MUCH OF THE AREA. WILL INCREASE POPS SOME. THE COLDEST OF THIS AIR IS IN A LAYER THAT THE GFS SEEMS TO NOT BE ABLE TO CAPTURE. WILL RELY ON THE MES NAM FOR LOW TEMPERATURES TONIGHT. && .SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/... SNOW SHOWERS WILL CONTINUE ACROSS THE N LOWLANDS AND N MOUNTAINS TUESDAY WITH A FETCH OFF LAKE ERIE AND CONTINUED CAA. THERE APPEARS TO BE A SUBTLE SPOKE OF ENERGY DIVING ON THE BACK SIDE OF THE TROF WHICH MAY ENHANCE THE SNOW SHOWERS AND EXPAND COVERAGE INTO THE C LOWLANDS AND REMAINDER OF THE MOUNTAINS. HAVE A FEW INCHES CODED UP IN THE HIGH TERRAIN WITH PERHAPS A DUSTING INTO S MOUNTAINS AND PARTS OF THE LOWLANDS TUESDAY EVENING. SURFACE HIGH BUILDS IN WEDNESDAY TO SHUT OFF THE SNOW SHOWERS. TRIED TO HOLD ONTO SOME STRATUS ACROSS WV FOR AT LEAST FIRST HALF OF THE DAY WITH SUBSIDENCE INVERSION DEVELOPING ATOP LINGERING LOW LEVEL MOISTURE. WAA SHOULD SCATTER THIS OUT LATER IN THE AFTERNOON. A QUICK MOVING CLIPPER TYPE SYSTEM WILL CROSS THURSDAY...WITH GOOD AMOUNT OF WAA AHEAD OF IT FOR WEDNESDAY NIGHT. THIS WILL LIKELY RESULT IN A NON DIURNAL TRACE...ESPECIALLY ACROSS THE RIDGES WHERE A GOOD RIDGE/VALLEY SPLIT WILL EXIST. RIGHT NOW IT APPEARS THIS SYSTEM WILL TRACK JUST N OF THE AREA RESULTING IN RAIN OUTSIDE OF THE MOUNTAINS. THERE COULD BE A BRIEF WINTRY MIX AT THE ONSET ACROSS SE OH AND N WV. PRECIP WILL CHANGE TO SNOW SHOWERS EVERYWHERE THURSDAY EVENING. FOR TEMPS...STAYED CLOSE TO THE NAM/MET GUIDANCE EARLY ON TO ACCOUNT FOR THE BETTER RESOLUTION IN THE LOW LEVEL COLD AIR. THIS RESULTS IN TUESDAY BEING RATHER COLD WITH MANY PLACES STRUGGLING TO MAKE IT TO 30 IN THE LOWLANDS. COLD TUESDAY NIGHT WITH TEENS LOWLANDS/SINGLE DIGITS HIGH ELEVATIONS. TEMPS REBOUND ON WEDNESDAY INTO THE LOW TO MID 30S. WITH AFOREMENTIONED WAA WEDNESDAY NIGHT...HAVE TEMPS RISING OVERNIGHT AFTER A QUICK FALL WEDNESDAY EVENING. THURSDAY SHOULD MAKE IT INTO THE 40S WITH SOME MID 40S S ZONES AND UP INTO FAVORED DOWNSLOPING AREAS. THE MOUNTAINS SHOULD STAY IN THE 30S. && .LONG TERM /FRIDAY THROUGH SUNDAY/...
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PERIOD STARTS WITH HIGH PRESSURE OVERHEAD...THAT ALMOST IMMEDIATELY GIVES WAY TO A LOW PRESSURE SYSTEM APPROACHING FROM THE W. MODELS ARE GENERALLY A BIT FASTER WITH THIS SYSTEM...SO PRECIPITATION COULD REACH WRN PORTIONS OF THE FCST AREA AROUND DAWN THU. THIS THEN SPREADS E ACROSS THE AREA THU...FOLLOWED BY UPSLOPE PRECIPITATION IN THE WAKE OF THE SYSTEM THU NT INTO FRI. WITH THE LOW CENTER TRACKING OF THE AREA...ENOUGH WARM AIR SHOULD ARRIVE FOR A MAINLY WET...NOT WHITE OR ICY...THU. HOWEVER...MIXED PRECIPITATION INCLUDING FREEZING RAIN COULD OCCUR AT THE BEGINNING IF PRECIPITATION IS ABLE TO RUSH IN BEFORE SFC TEMPERATURES CLIMB ABOVE FREEZING THU MORNING. HOWEVER...GIVEN MOST OF THE AREA WILL BE IN THE WARM SECTOR AHEAD OF A COLD FRONT THAT DOES NOT ARRIVE UNTIL EVENING...MOST OF THE PRECIPITATION SHOULD OCCUR IN THE AFTERNOON AND THEREFORE BE OF THE WET VARIETY. COLDER AIR COMING IN BEHIND THE SYSTEM CHANGES THE RAIN TO SNOW SHOWERS BUT THEN QUICKLY CUTS OFF THE PRECIPITATION FROM THE W AS THE DRIER AIR MOVES IN. UPSLOPE SNOW SHOWERS DIMINISH ON FRI...AS HIGH PRESSURE BUILDS IN FROM THE W...CUTTING OFF THE MOISTURE AND UPSLOPE FLOW. THIS SHOULD LEAD TO GOOD RADIATIVE COOLING FRI NT. ANOTHER SYSTEM AFFECTS THE AREA NEXT WEEKEND. THE MODELS REMAIN DIVERSE ON THE NATURE AND EVOLUTION OF THIS SYSTEM...BUT NONE ADVERTISE ANYTHING MAJOR...AND ALL SHOW THAT THE OVERALL COLD THEME IN A POSITIVE PNA CONTINUES. THUS HAVE THE CHANCE FOR LIGHT SNOW SHOWERS. AT OR VERY CLOSE TO WPC VALUES FOR TEMPERATURES...THEY LOOKED LIKE A VERY REASONABLE COMPROMISE BETWEEN THE INORDINATELY COLD AND DRY ECMWF HIRES...AND THE GFS BASED GUIDANCE...WHICH SEEMED TOO HIGH GIVEN ITS MASS FIELD SOLNS.
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&& .AVIATION /17Z MONDAY THROUGH FRIDAY/...
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FEELING THAT THE BEST COURSE OF ACTION IN THE AVIATION FORECAST TODAY IS PESSIMISTIC WITH PREVAILING IFR OR WORSE CONDITIONS. BAND OF SNOW IS NOW PUSHING EAST AND WILL BE EAST OF THE OHIO RIVER IN THE NEXT HOUR OR TWO. AS THIS SYSTEM MOVES EAST...FLOW TURNS TO THE NORTHWEST AND THE NORTHEAST MOUNTAINS GET INTO AN UPSLOPE REGIME. EKN AND CKB WILL BE MOST AFFECTED BY THIS...AS BKW WILL BE TOO FAR SOUTH THIS TIME AROUND. CONTINUE WITH THE IFR AT THESE LOCATIONS THE LONGEST...ALTHOUGH THE FLOW ITSELF WITHOUT SNOW WILL KEEP BKW BELOW 1KFT. HAVE IMPROVING CONDITIONS WHEN SNOW ENDS AT TERMINALS...BUT TO MVFR CEILINGS ONLY. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY... FORECAST CONFIDENCE: LOW TO MEDIUM. ALTERNATE SCENARIO: OBS MAY BOUNCE. TIMING ISSUES WILL EXIST. AMENDMENTS POSSIBLE. 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 M H M M M M M HTS CONSISTENCY H M L L H H H H H M L L BKW CONSISTENCY H H H H H H H H M M M M EKN CONSISTENCY M H H H M H M M M H M M PKB CONSISTENCY H H H H H M M M M M L M CKB CONSISTENCY H H H H H H H H H H H H AFTER 18Z TUESDAY... IFR POSSIBLE IN SNOW TUESDAY IN THE NORTHERN AND CENTRAL WV MOUNTAINS.
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&& .RLX WATCHES/WARNINGS/ADVISORIES...
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WV...NONE. OH...NONE. KY...NONE. VA...NONE.
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&& $$ SYNOPSIS...TRM/RPY/30 NEAR TERM...RPY/26 SHORT TERM...30 LONG TERM...TRM AVIATION...26

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