Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 031805 CCA AFDRLX AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE CHARLESTON WV 205 PM EDT MON AUG 3 2015 .SYNOPSIS... A COLD FRONT APPROACHES THIS EVENING...WITH SHOWERS AND THUNDERSTORMS. HIGH PRESSURE CROSSES TUESDAY INTO WEDNESDAY. A LOW PRESSURE SYSTEM CROSSES WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... A COLD FRONT APPROACHES FROM THE NORTHWEST EARLY TONIGHT. MODEL CONSENSUS IS TO BRING SHOWERS AND THUNDERSTORMS ACROSS SOUTHEAST OH BY 00Z TUESDAY AND SPREAD SOUTHEAST AND EAST OVERNIGHT. PLENTY OF AFTERNOON SUNSHINE PROVIDED ENOUGH HEATING TO GET STORMS GOING. MODELS INDICATE DEEP LAYERED SHEAR OF ABOUT 50 KNOTS ACROSS THE NORTHERN PORTIONS OF WV AND SOUTHEAST OH. ALTHOUGH SFC CAPE VALUES FROM THE NAM SEEMS TO BE EXAGGERATED BY HIGHER DEWPOINTS...STILL EXPECT ENOUGH BOUYANCY TO PRODUCE STRONG THUNDERSTORMS. SPC HAVE THE AREA UNDER A SLIGHT RISK FOR SEVERE WEATHER ACROSS NORTHEAST KY...SOUTHEAST OH AND THE WESTERN HALF OF WV THROUGH TONIGHT. ADJUSTED POPS TO REFLECT THE CONSENSUS OF MODELS...STARTING PCPN ACROSS SOUTHEAST OH AROUND 00Z...THEN SPREAD SOUTHEAST AS IT LOOSEN ITS GRIP BY LOOSING DIURNAL HEATING. HOWEVER...BOUNDARY LAYER CONVERGENCE LOOKS DESCENT WITH THE FRONT...AND WITH DEEP LAYERED SHEAR AROUND 50 KNOTS...STORMS COULD LINGER INTO AT LEAST MIDNIGHT. BLENDED THE SUPER BLEND NUMBERS WITH PREVIOUS FORECAST FOR TEMPERATURES THROUGH THE PERIOD. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... MAIN HIGHLIGHT THIS PERIOD IS A DRIER FCST FOR TUE INTO WED...AS HIGH PRESSURE BUILDS BEHIND A COLD FRONT THAT EXITS THE AREA TUE MORNING. WITH THE COLD FRONT STALLING NOT FAR TO THE S OF THE FCST AREA...STILL HAVE SCHC POPS ACROSS THE FAR SRN TIER INTO WED. MODELS CONCUR BROADLY ON THE IDEA OF A SRN STREAM S/W TROUGH AND SFC LOW PRESSURE SYSTEM APPROACHING FROM THE W BY THU MORNING. THERE WAS ABOUT A 10MB DIFFERENCE ON THE PRESSURE OF THE SFC LOW CENTER...THE NAM BEING THE LOWER AT 1001 MB WHICH IS ON THE LOW SIDE FOR A LOW CENTER IN SRN IL IN MID SUMMER. THE ECMWF IS SQUARELY IN BETWEEN AND LOOKED REASONABLE. THE FRONT TO THE S RETURNS AS A WARM FRONT WED AND WED NT...BRINGING BACK THE CHC FOR SHOWERS AND THUNDERSTORMS COMING IN FROM THE W IN AN AXIS SHIFTING FROM S TO N AS IT PUSHES E. AS A RESULT...PRECIPITATION APPEARS MOST LIKELY ACROSS NRN PORTIONS OF THE FCST AREA BY 12Z THU. PREFERRED THE ECMWF QPF WHICH BEST DEPICTS THIS. THE BEST CHANCE FOR THUNDERSTORMS WILL BE CLOSE TO AND S OF THE FRONT...ALTHOUGH ELEVATED THUNDER IS POSSIBLE FARTHER N EARLY THU MORNING. TEMPERATURES CLOSE TO STRAIGHT UP GUIDANCE BY DAY AND BIAS CORRECTED GUIDANCE BY NT. LOWS AND DEW POINT FCST BETTER REFLECT N-S GRADIENT ASSOCIATED WITH FRONT TO THE S TUE INTO WED. DIFFERENTIAL CLOUD COVER MUDDLES THE HIGH TEMPERATURE FCST A BIT ACROSS THE BAROCLINIC ZONE. && .LONG TERM /THURSDAY THROUGH MONDAY/... EXTENDED CONTINUES TO PLAY ON THE SURFACE LOW DEVELOPING OFF TO THE WEST AND MOVING INTO THE CENTRAL APPALACHIANS WARRANTING HIGH END CHANCE TO LIKELY POPS ON THE FRONT END OF THE LONG TERM. THIS LOW DEPARTS TO THE EAST BY 18Z FRIDAY AND WILL TAKE THE BULK OF THE RAIN CHANCES WITH IT. CANADIAN HIGH PRESSURE BUILDS IN BEHIND THE LOW AND COLD FRONT DRYING IT OUT FOR THE WEEKEND WITH TEMPERATURES SLIGHTLY BELOW NORMAL AREA WIDE. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... VFR CONDITIONS TO START THE PERIOD...BEFORE SHOWERS AND STORMS DEVELOP LATE THIS AFTERNOON AND EVENING INTO TONIGHT AHEAD OF A PASSING COLD FRONT. THE COLD FRONT WILL BE ACROSS CENTRAL WV BY 06Z...AND SOUTH OF THE AREA BY 12Z TUESDAY. BRIEF PERIODS OF IFR/MVFR CONDITIONS EXPECTED WITH THE STRONGER SHOWERS. STRONG GUSTY WINDS EXPECTED ALONG STRONGER STORMS AS THEY COULD BECOME SEVERE TONIGHT. DIFFICULT TO PINPOINT WHERE AND WHEN THE STRONGEST STORMS WILL BE. THEREFORE...CODED VCTS AT MOST SITES FOR NOW...IMPENDING AMENDMENTS. BEHIND THE FRONT...LINGERING LIGHT SHOWERS COULD PRODUCE MVFR CONDITIONS AND LOW CEILINGS OVERNIGHT INTO TUESDAY MORNING. BULK OF CONVECTION SHOULD WANE AFTER 09Z...BUT WIDESPREAD MVFR CIGS POSSIBLE MAINLY ACROSS SOUTHERN WEST VIRGINIA...THE MOUNTAINS OF WEST VIRGINIA...AND SOUTHWEST VA. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING OF CONVECTION AND ASSOCIATED FLIGHT RESTRICTIONS LATE THIS AFTERNOON AND EVENING COULD VARY. DEVELOPMENT AND EXTENT OF MVFR CIGS LATE TONIGHT MAY VARY FROM FORECAST. 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 EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 CRW CONSISTENCY H H H H H H H H H H H M HTS CONSISTENCY H H H H H H H H H H H M 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 M M H PKB CONSISTENCY H H H M M M M M M H H H CKB CONSISTENCY H H H H H H M M M M M H AFTER 18Z TUESDAY... IFR POSSIBLE AGAIN WEDNESDAY NIGHT AND THURSDAY IN SHOWERS AND THUNDERSTORMS. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...JS/ARJ NEAR TERM...ARJ SHORT TERM...TRM LONG TERM...26 AVIATION...ARJ

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