Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 270731 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 224 AM EST TUE JAN 27 2015 .SYNOPSIS... COLD NORTHWEST FLOW TODAY AND TONIGHT. HIGH PRESSURE WEDNESDAY. LOW PRESSURE THURSDAY. HIGH PRESSURE SATURDAY. && .NEAR TERM /THROUGH TONIGHT/... MODELS CONTINUE TO SHOW SOME LOW LEVEL MOISTURE PERSISTING OVER MUCH OF THE FORECAST AREA TODAY...WITH EMBEDDED DRY POCKETS MAKING THE FORECAST ESPECIALLY TRICKY. LOW LEVEL COLD AIR COMBINED WITH THE MOISTURE AND UPSLOPE WILL KEEP CHANCES FOR SNOW IN MANY AREAS...ESPECIALLY THE NORTHERN MOUNTAINS OF WEST VIRGINIA. WITH MESO NAM HAVING BETTER RESOLUTION THAN THE GFS IN THE LOW LEVELS WHERE THE COLDER AIR IS LOCATED...OPTED TO STAY CLOSER TO THE MET MOS FOR BOTH TEMPERATURES AND DEWPOINTS TODAY. WITH WINDS BECOMING FAIRLY LIGHT IN SOUTHEAST OHIO AND KENTUCKY TONIGHT AND CLOUDS CLEARING...WENT ON THE LOWER SIDE OF MOS GUIDANCE THERE. && .SHORT TERM /WEDNESDAY/... NORTHWEST UPSLOPE FLOW...COLD AIR AND SUFFICIENT LOW-LEVEL MOISTURE WILL RESULT IN A CONTINUING CHANCE OF ACCUMULATING SNOW...ESPECIALLY ACROSS THE FAVORABLE NORTHERN MOUNTAINS AREAS...EARLY TUESDAY NIGHT. HOWEVER...SURFACE HIGH WILL BUILDS IN AND SHUT OFF THE SNOW SHOWERS BY SUNRISE ON WEDNESDAY. THIS HIGH WILL REMAIN IN CONTROL OF OUR WEATHER THROUGH WEDNESDAY NIGHT...WHEN A FAST MOVING CLIPPER TYPE SYSTEM APPROACHES THE AREA FROM THE WEST. PRECIPITATION SHOULD OVERSPREAD THE REGION FROM THE WEST ON THURSDAY...AS A WARM FRONT PUSHES NORTHEAST DURING THE DAY. A COLD FRONT SHOULD THEN FOLLOW AND SHOULD BE LOCATED NEAR THE OHIO RIVER BY LATE THURSDAY. FOR TEMPS...GENERALLY WENT WITH A BLEND OF THE NAM/MET GUIDANCE TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. USED HPC NUMBERS WITH SOME TWEAKS FOR HIGHS ON THURSDAY. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... ACTIVE WEATHER PATTERN CONTINUES WITH ONE SYSTEM MOVING ACROSS THURSDAY NIGHT AND ANOTHER STRONGER SYSTEM OVER THE WEEKEND. THE FIRST SYSTEM WILL BE A WEAKER CLIPPER LIKE SYSTEM THAT COMES OVER THE STILL HIGH AMPLITUDE UPPER RIDGE IN THE WEST AND ROLLS ACROSS THE OHIO VALLEY. MODELS IN BASIC AGREEMENT ON THE TRACK AND SPEED OF THE SURFACE LOW...WHICH GOES JUST NORTH OF OUR AREA AND PUSHES A COLD FRONT RAPIDLY ACROSS THURSDAY NIGHT. THE TYPICAL WARM SOUTHERLY FLOW AHEAD OF THIS FRONT WILL BRING LIGHT RAIN EARLY THURSDAY NIGHT...FOLLOWED BY POST FRONTAL SNOW SHOWERS IN SIGNIFICANT COLD ADVECTION...ESPECIALLY IN THE NORTHERN AND CENTRAL MOUNTAINS WHERE UPSLOPE WILL KICK IN. HOWEVER...THE SPEED OF THE SYSTEM...AND HIGH PRESSURE BUILDING LATER FRIDAY...WILL LIMIT THE OVERALL SNOW ACCUMULATIONS. WE GENERALLY EXPECT LITTLE ACCUMULATION IN THE LOW LANDS BY THE TIME SNOW TAPER OFF LATER FRIDAY MORNING...AND ACCUMULATIONS IN THE NORTHERN MOUNTAINS MAY BE A FEW INCHES BEFORE TAPERING OFF LATER FRIDAY AFTERNOON. TEMPERATURES WILL BE BELOW NORMAL BEHIND THE FRONT...WITH TEMPERATURES STRUGGLING TO REACH FREEZING FRIDAY AFTERNOON. SATURDAY LOOKS TO BE THE IN BETWEEN DAY OF SYSTEMS WITH A RATHER TRANQUIL BY COLD HIGH PRESSURE SYSTEM OVER OUR AREA...TEMPERATURES REMAINING BELOW NORMAL. THE NEXT SYSTEM TO AFFECT US SUNDAY AND MONDAY LOOKS TO BE A STRONG AND WET SYSTEM AS A RATHER POTENT PACIFIC SYSTEM CRASHES THRU THE WESTERN UPPER RIDGE. THE BIG QUESTION HERE IS WHETHER THIS SYSTEM PHASES WITH THE NORTHERN STREAM BY THE TIME IT REACHES US. THIS IS VERY MUCH IN QUESTION...AND WILL CONTINUE WITH A MORE DETACHED SOUTHERN ROUTE PER OUR CURRENT FORECAST...WPC...AND MAJORITY OF GUIDANCE. THUS...WILL CONTINUE TO GO WITH A SNOW SYSTEM EXCEPT POSSIBLY OVER THE SOUTHERN PORTIONS. HOWEVER...IT SHOULD BE NOTED AT THIS TIME FRAME...THERE IS STILL PLENTY OF TIME FOR MODEL CHANGES IN HANDLING THE SYSTEM. && .AVIATION /08Z TUESDAY THROUGH SATURDAY/... A NORTHWEST WIND FLOW WILL COMBINE WITH LOW LEVEL MOISTURE TO KEEP A STRATUS DECK OVER PORTIONS OF THE AREA THROUGH TUESDAY NIGHT. THERE WILL BE HOLES AND AREAS THAT CLEAR HOWEVER...MAKING FOR A RATHER TRICKY FORECAST. IN ADDITION...SOME RESTRICTIONS IN UPSLOPE SNOW SHOWERS ARE A POSSIBILITY...WITH THE BEST CHANCES IN THE NORTHERN MOUNTAINS OF WV. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z WEDNESDAY... FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z WEDNESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIO: TIMING AND LOCATION OF CLEARING AREAS/HOLES IN THE STRATUS COULD VARY. 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 01/27/15 UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17 EST 1HRLY 01 02 03 04 05 06 07 08 09 10 11 12 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 L L L L L L L H H H H H EKN CONSISTENCY L L L L L L L 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 06Z WEDNESDAY... IFR CONDITIONS POSSIBLE THURSDAY MORNING IN SNOW SWITCHING TO RAIN LATER. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...JSH/JMV NEAR TERM...RPY SHORT TERM...JSH LONG TERM...JMV AVIATION...RPY

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