Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 140736 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 336 AM EDT MON APR 14 2014 .SYNOPSIS...
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STRONG COLD FRONT MONDAY NIGHT. HIGH PRESSURE REST OF THE WORK WEEK.
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&& .NEAR TERM /THROUGH TONIGHT/...
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00Z RUN OF THE NAM CAME OUT WITH A DISTINGUISHED LINE OF CONVECTION WELL AHEAD OF THE COLD FRONT AND THE MID AND UPPER LEVEL TROUGH AXES. GFS CAME IN SUPPORTING THE SAME FEATURE...WITH THE HRRR IN LINE AS WELL AS THE LINE COMES INTO THE SCOPE OF THAT MODEL/S FORECAST RANGE. THIS IS THE ONLY MAJOR CHANGE TO THE FORECAST. SPC KEEPS THE SLIGHT RISK OF SEVERE WEATHER WELL TO THE SOUTH THANKS TO LOW DEWPOINTS CONTRIBUTING TO LOW SURFACE BASED CAPE. A DEVELOPING WAVE ALONG THE FRONT WILL KEEP THE PRECIPITATION CHANCES ENHANCED THROUGH THE MONDAY NIGHT PERIOD...WITH THE HINTS OF CLEARING COMING IN THE NORTHWEST ZONES AT 12Z TUESDAY IN THE FORM OF POPS DROPPING TO CHANCE. AFTER A VERY WARM MORNING...TEMPERATURES WILL PUSH THE 80F MARK AGAIN TODAY...COOLER WITHOUT MUCH SUN TO SPEAK OF...BUT STILL WELL ABOVE NORMAL IN THE WARM SECTOR.
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&& .SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
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GOOD MODEL AGREEMENT ON TIMING OF THE STRONG COLD FRONT EXITING THE MOUNTAINS EARLY TUESDAY MORNING...FOLLOWED BY MOSTLY FALLING TEMPERATURES DURING THE DAY. POST FRONTAL PRECIPITATION WILL END FROM WEST TO EAST DURING THE DAY...WITH MODELS ALSO AGREEING ON THE EXIT TIMING OF THE DEEPER MOISTURE AND PRECIP WITH THE SYSTEM. BY DAYS END ONLY A SLIGHT CHANCE WILL LINGER IN THE NORTHERN MOUNTAINS...ENDING BY MIDNIGHT. THE BIG CHALLENGE IS THE NON DIURNAL TEMPERATURE CURVE DURING TUESDAY...IN THE VERY STRONG COLD ADVECTION AND UNUSUALLY COLD AIRMASS FOR THIS TIME OF YEAR...AND THUS THE PROSPECTS OF RAIN TO SNOW. GIVEN THE COLD MODEL CONSENSUS ALOFT WHICH WOULD SUPPORT A CHANGEOVER TO SNOW FROM WEST TO EAST TOWARD THE END OF THE PRECIPITATION...THE ISSUE WILL BE THE BOUNDARY LAYER TEMPERATURES. MODELS DO SHOW STRONG TEMPERATURE FALLS IN THE MORNING AND TENDING TO LEVEL OUT FOR A TIME IN THE LOW LANDS IN THE AFTERNOON...BEFORE FALLING AGAIN TUESDAY NIGHT. THIS IS REASONABLE FOR THIS TIME OF YEAR...AND ESPECIALLY IN THE WEST AND CENTRAL AS PRECIPITATION ENDS EARLIER IN THE DAY. WILL GO WITH THE NAM MOS GUIDANCE...MAINLY BECAUSE IT BEST SHOWS A BREAK IN THE TEMPERATURE FALLS DURING THE AFTERNOON...ESPECIALLY WEST AND CENTRAL. THUS...BELIEVE ANY MIX/CHANGEOVER TO SNOW IN THE LOW LANDS WILL BE BRIEF BEFORE THE PRECIPITATION ENDS WITH NO ACCUMULATIONS...AS SURFACE TEMPERATURES WILL STILL BE ABOVE FREEZING AND THE GROUND QUITE WARM. IN THE CENTRAL AND NORTHERN MOUNTAINS...THERE WILL BE A CHANGEOVER TO SNOW DURING THE AFTERNOON...BUT ACCUMULATIONS WILL LIKELY BE AN INCH OR LESS AND MOSTLY CONFINED TO THE HIGHER ELEVATIONS. LOOK FOR TEMPERATURES TO START OUT TUESDAY MORNING IN THE 50S EAST AND NEAR 40 FAR WEST...REACHING BY EVENING THE LOW TO MID 30S MOST OF THE LOW LANDS AND BELOW FREEZING ABOVE 2000 FEET. WHILE SNOW SHOWERS TAPER OFF EARLY TUESDAY NIGHT IN THE MOUNTAINS... CLEARING FOLLOWS MORE SLOWLY WITH THE COLD ADVECTION AND UPSLOPE FLOW IN THE MOUNTAINS. STILL...IT SHOULD BECOME MOSTLY CLEAR EARLY ENOUGH AS DRY HIGH PRESSURE BUILDS IN RAPIDLY FROM THE WEST...AND ALLOW TEMPERATURES TO FALL WELL BELOW FREEZING IN ALL LOCATIONS. HOWEVER...BELIEVE THE MODELS MAY BE A BIT ON THE LOW SIDE AS THEY FORECAST A RUN FOR RECORD LOWS TUESDAY NIGHT. FOR NOW...WILL KEEP OUR MINS A COUPLE OF DEGREES ABOVE THE MOS...BUT STILL WELL BELOW FREEZING. THEREAFTER...HIGH PRESSURE SLIDES ACROSS WITH ABUNDANT SUNSHINE WEDNESDAY AND THURSDAY...ALONG WITH A WARMING TREND. WITH DRY AIR AND LIGHT WINDS WEDNESDAY NIGHT...TEMPERATURES COULD FALL BELOW FREEZING AGAIN.
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&& .LONG TERM /FRIDAY THROUGH SUNDAY/... SW FLOW DOMINATES THROUGH FRIDAY BEFORE S/W TROF TRIES TO CREATE FOR AN UNSETTLED SATURDAY. DUE TO CONTINUED DIFFERENCES REGARDING AMPLITUDE AND STRENGTH OF SURFACE FEATURES...HAVE STAYED CLOSE TO WPC PREFERRED SOLUTION WITH THREAT FOR SHRA FRIDAY NIGHT AND SATURDAY. FOR TEMPS...A WARMING TREND WILL BE NOTED TO ROUND OUT THE WORK WEEK...BEFORE COOLER BUT MORE SEASONAL AIR ARRIVES FOR THE WEEKEND. && .AVIATION /08Z MONDAY THROUGH FRIDAY/...
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VFR EXPECTED AHEAD OF THE CONVECTION ASSOCIATED WITH A STRONG FRONTAL SYSTEM. CEILINGS WILL GRADUALLY LOWER...WITH CONVECTION ENTERING THE WESTERN TERMINALS AT AROUND 17Z-18Z. PREFERRING MVFR CONDITIONS TO PREVAIL WITH VCTS FOR NOW GIVEN THE ATMOSPHERIC SET UP. EXPECTING SOUTHERLY WINDS IN THE WARM SECTOR WHICH WILL TYPICALLY LEND TO HIGHER CEILINGS...EVEN IN SHRA/TSRA. TEMPOS WILL LIKELY BE NEEDED FOR BRIEF IFR VISIBILITIES. WILL REEVALUATE THE PREVAILING TSRA POTENTIAL FOR THE 12Z TAF ISSUANCE. SPEAKING OF VISIBILITIES...NOT EXPECTING BR/FG TO SETTLE IN BETWEEN ROUNDS OF SHRA/TSRA GIVEN THE STRONG GRADIENT WIND SET UP. MAY GET SOME GUSTS WITH THE CONVECTION...ALSO NECESSITATING TEMPOS AS WELL. COLD FRONT SHOULD NOT PASS BEFORE 06Z TUESDAY...SO WILL NOT SEE THE WIND DIRECTION SHIFT IN THIS PERIOD. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z TUESDAY... FORECAST CONFIDENCE: HIGH THROUGH 18Z. MEDIUM AFTER. ALTERNATE SCENARIOS: CONVECTION TIMING AND BRIEF FLIGHT CATEGORY BOUNCES COULD LEAD TO TEMPOS AND AMENDMENTS. MAY NEED PREVAILING TSRA. 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 MON 04/14/14 UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19 EDT 1HRLY 04 05 06 07 08 09 10 11 12 13 14 15 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 06Z TUESDAY... IFR CONDITIONS EXPECTED LATE MONDAY NIGHT UNDER MODERATE RAIN SHOWERS.
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&& .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...JMV/26 NEAR TERM...26 SHORT TERM...JMV LONG TERM...30 AVIATION...26

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