Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 270620 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 220 AM EDT MON JUL 27 2015 .SYNOPSIS... REMNANTS OF A COLD FRONT SPLATTER PATCHY PRECIP OVER THE FORECAST AREA TODAY. HEAT BUILDS MONDAY INTO WEDNESDAY. STRONGER FRONT ABOUT THURSDAY. && .NEAR TERM /THROUGH TONIGHT/... COLD FRONT STALLED WELL NORTH OF OUR AREA...BUT UPPER JET AND VORT MAX COUPLET ARE USHERING IN SOME SCATTERED SHOWERS THAT ARE MAINLY PRODUCING VIRGA. WITH JUICY DEW POINTS...AS WE ARE STILL ENTRENCHED IN A WARM AIR MASS...ANY HEATING TODAY WILL TRANSLATE INTO INSTABILITY WHICH COULD CAUSE A FEW DUMPERS THIS AFTERNOON. THE PRIMARY AXIS OF THESE WOULD OCCUR ALONG THE SE WV MTNS. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... HARD TO SAY WHAT WILL REMAIN OF THE WEAKENING...DIFFUSE COLD FRONT BY THE START OF THE SHORT TERM. ENOUGH MOISTURE WILL REMAIN TO POSSIBLY KICK OFF ISOLATED TO SCATTERED TSHOWERS ACROSS THE HIGHER TERRAIN TUESDAY AFTERNOON AND TO A LESSER EXTENT WEDNESDAY AFTERNOON. BY THEN...ATTENTION IS TURNING TO STRONGER COLD FRONT APPROACHING FROM THE WEST. MODELS AGREEING ON SPEEDING THIS FEATURE UP...BUT LEERY TO GO TO FAST AS FRONTS TYPICALLY SLOW DOWN AS THE APPROACH US AND MODELS OFTEN ARE A BIT TOO FAST. SO DID SPEED UP PREVIOUS FORECAST SOME...BUT NOT AS FAST AS CURRENT MODEL SUITE WOULD SUGGEST. HAVE THE FRONT CROSSING THE OHIO RIVER PRE- DAWN THURSDAY MORNING...THEN MOVING EASTWARD ACROSS THE REST OF THE CWA THROUGH EARLY AFTERNOON. INCREASED POPS TO HIGH CHANCE AS WELL ALONG AND AHEAD OF THE FRONT. POPS THEN DECREASING FROM WEST TO EAST THURSDAY AFTERNOON AND THURSDAY NIGHT. BUMPED UP HIGHS ON TUESDAY AND WEDNESDAY AFTERNOONS A BIT...WITH UPPER RIDGE OVER THE MISSISSIPPI VALLEY. NOW HAVE LOW 90S ACROSS THE LOWLANDS BOTH DAYS. && .LONG TERM /THURSDAY THROUGH SUNDAY/... BY FRIDAY MORNING...COLD FRONT SHOULD BE SOUTH OF OUR AREA WITH DRIER CONDITIONS PREVAILING AS A RIDGE AXIS BEGINS TO ANCHOR ITSELF ACROSS THE OHIO VALLEY. THERE IS GENERAL AGREEMENT IN THIS SOLUTION AMONG LONG RANGE MODELS. HOWEVER...THERE IS MUCH DISAGREEMENT CONCERNING EVOLUTION OF THE RIDGE THROUGH THE LATE WEEK AND INTO THE WEEKEND...AS WELL AS THE POSSIBILITY OF ANOTHER FRONT BY THE END OF THE PERIOD. THE GFS MAINTAINS A FAIRLY NARROW EAST/WEST RIDGE ACROSS THE OHIO VALLEY...WITH SOME DIURNAL THUNDERSTORM ACTIVITY IN THE MOUNTAINS SATURDAY AFTERNOON...AND ANOTHER COLD FRONT APPROACHING BY LATE SUNDAY AND EARLY MONDAY. THE EURO IS CONSIDERABLY DRIER...WITH A MORE EXPANSIVE RIDGE...LESS OPPORTUNITY FOR AFTERNOON RAIN OR STORMS...AND THE ABSENCE OF ANY FRONTAL FEATURE FOR SUNDAY/MONDAY. CONSIDERING THE HIGH LEVEL OF UNCERTAINTY IN THIS FORECAST...RELIED MORE ON WPC FOR GUIDANCE...WITH GENERALLY WARMING TEMPS THROUGH THE PERIOD AND LOWER-END AFTERNOON POPS FOR THE MOUNTAINS ON SATURDAY. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... BIGGEST CONCERN IS POTENTIAL FOR IFR/LIFR FOG. MODELS GOING WITH FG/BR FOR MANY SITES...BUT DEW POINTS ARE SO HIGH AND MID TO UPPER LEVEL CLOUD COVER SHOULD PREVENT ANY GOOD RADIATIVE COOLING...SO QUITE HESITANT TO INCLUDE IN TAFS. WILL SAY MODELS ARE HAVING ISSUES DEALING WITH BL THERMODYNAMICS COMPARED TO OBS...WHICH MAY BE A REASON FOR THERE OVERFORECASTING OF FOG. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z TUESDAY... FORECAST CONFIDENCE: MEDIUM TO HIGH. ALTERNATE SCENARIOS...MIST/FOG DURING THE 06Z TO 12Z MON MAY BE THICKER IN WV MOUNTAIN VALLEYS THAN FORECAST IF CLOUDS BREAK UP. 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 07/27/15 UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17 EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13 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... AHEAD OF...AND ALONG...FRONT...IFR POSSIBLE IN SHOWERS/STORM OVERNIGHT WEDNESDAY NIGHT INTO THURSDAY. LOW CLOUDS/FOG POSSIBLE IN WAKE OF FRONT IN THE SOUTH AND EAST THURSDAY NIGHT. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...MZ/JW/DTC NEAR TERM...JW SHORT TERM...MZ LONG TERM...DTC AVIATION...JW

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