Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 300705 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 305 AM EDT SAT APR 30 2016 .SYNOPSIS... WARM FRONTAL SHOWERS INCREASE TODAY. MORE INSTABILITY SUNDAY WITH COLD FRONT SINKING SOUTHEAST SUNDAY NIGHT. DRIER MONDAY. WAVE PASSES TO THE SOUTHEAST TUESDAY. && .NEAR TERM /THROUGH TONIGHT/... A WARM FRONT WILL GRADUALLY LIFT NORTH...BRINGING SCATTERED TO NUMEROUS SHOWER WITH EMBEDDED THUNDERSTORMS THIS AFTERNOON AND EVENING. HIGH RESOLUTION MODELS ARE IN AGREEMENT WITH THE ONSET OF PCPN OVER SOUTHERN WV AND NORTHEAST KY BY 18Z SATURDAY. PRECIPITABLE WATER ABOUT 1.25 INCHES...DESCENT DEEP LAYERED SHEAR ABOUT 45 KNOTS...BUT LOW SFC CAPE WITH COMBINE TO PRODUCE MAINLY SHOWERS THROUGH TONIGHT. MODELS INDICATE H850 TEMPERATURES WILL BE AROUND 12C THROUGH THE PERIOD. TEMPERATURES WILL BE MILD DUE TO CLOUD COVER AND COOLING SHOWERS...GENERALLY IN THE LOWER 70S LOWLANDS...RANGING INTO THE LOWER 60S HIGHER ELEVATIONS. WENT CLOSER TO THE NATIONAL BLEND OF MODELS FOR TEMPERATURES THROUGH THE PERIOD. && .SHORT TERM /SUNDAY THROUGH MONDAY/... A RATHER MESSY FORECAST STILL FOR SATURDAY NIGHT THROUGH SUNDAY. LOOKS LIKE WE MAY HAVE A DRY PERIOD SATURDAY NIGHT ACROSS THE WEST...BUT STILL HANGING ONTO CHANCE POPS. HAVE LIKELY POPS ACROSS THE MOUNTAINS. ENTIRE CWA SHOULD GET SOME RAIN ON SUNDAY...BUT TIMING IS RATHER DIFFICULT. NAM SHOWS SOME BREAKS DURING THE AFTERNOON...WITH THE MAIN SLUG IN THE MORNING...WHILE GFS AND ECMWF HAVE LESS DEFINITION. THIS ALL MAKES IT DIFFICULT TO HIGHLIGHT WHEN THESE DRIER PERIODS MAY BE ON SUNDAY...SO GENERALLY KEPT HIGH POPS THROUGHOUT THE DAY...GRADUALLY TAPERING OFF SUNDAY NIGHT INTO MONDAY. DESPITE THE SHOWERS AND CLOUDS AROUND IN THE MORNING...THE NAM STILL INDICATED SOME DECENT INSTABILITY SUNDAY. IN ADDITION...NAM BULK SHEAR HAS INCREASED IN RECENT RUNS -- NOW GENERALLY 40-50KTS SUNDAY AFTERNOON. THINK THE MORNING ACTIVITY SHOULD LIMIT INSTABILITY SOME...BUT STILL CANNOT RULE OUT SOME STRONGER THUNDERSTORMS WITH GUSTY WINDS AND POSSIBLY HAIL. ALONG PWATS LOOK TO BE THE HIGHEST SATURDAY NIGHT ACROSS THE WESTERN HALF OF THE CWA...MAXING OUT JUST OVER 1.5 IN. GENERALLY HAVE ABOUT 1 INCH OF QPF SATURDAY NIGHT THROUGH SUNDAY NIGHT. BUT ANY AREAS THAT RECEIVE REPETITIVE DOWNPOURS COULD START EXPERIENCING MINOR WATER ISSUES. WILL KEEP MENTION IN HWO FOR NOW. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... MODELS STILL DIFFER ON WAVE CROSSING THE MIDDLE ATLANTIC STATES TUESDAY INTO WEDNESDAY...BUT THERE IS INCREASING CONSENSUS ITS MOISTURE AFFECTS AT LEAST SOUTHEASTERN PORTIONS OF THE FORECAST AREA. MODELS ALSO REMAIN A BIT OUT OF SYNC WITH A COUPLE OF NORTHERN STREAM SYSTEMS THAT CROSS MID TO LATE WEEK. THE GFS BRINGS COLD FRONTS ACROSS LATE WEDNESDAY AND THEN FRIDAY NIGHT...WHILE THE ECMWF TIMING IS EARLY THURSDAY ON THE FIRST COLD FRONT...AND THEN IT JUST CLOSES OFF A LARGE UPPER LOW THAT THEN SLOWLY LUMBERS THROUGH THE AREA AT LEAST THE END OF THE PERIOD. THE GFS IS FARTHER NORTH AND DEEPER WITH THE UPPER LOW...HENCE THE MORE DEFINED SECOND SURFACE FRONT. AS FOR THE UPPER LOWS...THIS IS A CLASSIC CASE OF DEEPER...BY ABOUT 350M...AND FARTHER NORTH VERSUS WEAKER AND FARTHER SOUTH. THE CURRENT FORECAST BRINGS FRONTS AND THE ASSOCIATED CHANCE FOR SHOWERS ACROSS WEDNESDAY AND FRIDAY NIGHTS...SIMILAR TO THE WPC DEPICTION. KEPT LOWS CLOSE TO PREVIOUS FORECAST AND A GUIDANCE BLEND. BLENDED IN GFS-BASED GUIDANCE FOR HIGHS...A LITTLE LOWER THAN PREVIOUS FORECAST FOR THE MOST PART. && .AVIATION /07Z SATURDAY THROUGH WEDNESDAY/... OVERNIGHT...VFR CONDITIONS WILL PREVAIL...EXCEPT AT EKN...PKB...AND CKB THAT COULD SEE SOME MVFR/IFR FOG DURING THE PREDAWN HOURS. SATELLITE IMAGES SHOW HIGH CLOUDS CREEPING IN FROM THE SOUTH AND WEST...SHOULD GENERALLY PREVENT DENSE FOG DEVELOPMENT OVERNIGHT. A WARM FRONT LIFTS NORTH ON SATURDAY...WITH SCATTERED SHOWERS AND ISOLATED STORMS DURING THE EARLY AFTERNOON. WIDESPREAD MVFR CONDITIONS DEVELOPING AFTER 15-18Z...PARTICULARLY ACROSS THE EASTERN SLOPES OF THE HIGHER TERRAIN AND AT SITES SUCH AS KBKW AS A SOUTHEASTERLY FLOW TAKES HOLD. WV LOWLANDS MAY BE SLOWER TO DEVELOP MVFR CONDITIONS IN THE SOUTHEASTERLY DOWNSLOPING FLOW. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SUNDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: CLOUD COVER COULD PREVENT FOG DEVELOPMENT TONIGHT. TIMING...COVERAGE AND DURATION OF ANY FOG OVERNIGHT TONIGHT COULD VARY. TIMING AND DEVELOPMENT OF MVFR CONDITIONS ON SATURDAY COULD 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. DATE SAT 04/30/16 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 M M HTS CONSISTENCY H H H H H H H H H M M M BKW CONSISTENCY H H H H H H H H H M M M EKN CONSISTENCY L L L L L L L H H H H H PKB CONSISTENCY L L L L L L L M H H H H CKB CONSISTENCY L L L L L L L H H H H H AFTER 06Z SUNDAY... IFR POSSIBLE AGAIN SATURDAY NIGHT INTO SUNDAY NIGHT WITH ADDITIONAL ROUNDS OF SHOWERS AND THUNDERSTORMS..AND IN STRATUS LINGERING INTO MONDAY MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB/TRM/MZ NEAR TERM...ARJ SHORT TERM...MZ LONG TERM...TRM AVIATION...ARJ

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