Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 041032 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 632 AM EDT WED MAY 4 2016 .SYNOPSIS... COLD FRONT CROSSES WEDNESDAY NIGHT. LARGE UPPER LEVEL LOW BRINGS COOL AND UNSETTLED WEATHER FOR THURSDAY THROUGH FRIDAY. WARM FRONT SATURDAY. ANOTHER COLD FRONT SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... WEAK SURFACE HIGH SHIFTS EAST THIS AFTERNOON AND FOR THE MOST PART WINDS WILL BE LIGHT THROUGH THE DAY WITH SOUTHWEST WINDS PICKING UP SLIGHTLY AHEAD OF AN APPROACHING COLD FRONT LATER IN THE AFTERNOON AND EARLY EVENING. DECIDED TO KEEP POP CLOSE TO PREVIOUS FORECAST WITH BULK OF SHOWERS ARRIVING LATE AFTERNOON TO EARLY EVENING WITH THE COLD FRONT AS NAM/GEM/AND MESO MODELS ARE ADVERTISING. UPPER LEVEL LOW DIVING SOUTHWARD WILL BRING COLD TEMPS ALOFT WITH T700 -2 STANDARD DEVIATIONS BELOW NORMAL. INSTABILITY WILL BE WEAK BUT WITH SUCH LOW FREEZING LEVELS...ANY STORMS THAT DEVELOP WILL LIKELY BRING SMALL HAIL OR GRAUPEL THIS AFTERNOON AND EVENING. THIS SYSTEM DOES NOT ADVERTISE HIGH PWATS WITH IT...SO NOT EXPECTING TORRENTIAL RAIN. HOWEVER...WE HAVE TO STILL KEEP A CLOSE EYE ON THE FLASH FLOOD THREAT DUE TO WEAK FLOW ALOFT WITH A UPPER LEVEL SYSTEM. CORFIDI VECTORS...GENERALLY LESS THAN 10KTS COULD MAKE FOR NEARLY STATIONARY SHOWERS/STORMS AND TRAINING OR BANDING WILL BE A REAL POSSIBILITY AS UPPER LOW PIVOTS ACROSS OUR AREA TONIGHT. THE BEST CHANCE FOR HEAVIER RAINFALL WILL LIKELY BE IN OUR EASTERN MOUNTAINS...WHERE UPSLOPING COULD ENHANCE RAINFALL TOTALS. OVERALL QPF SHOULD BE FAIRLY LIGHT IN MOST AREAS...BUT LOCALIZED HEAVY RAINFALL WILL BE POSSIBLE WITH SLOW MOVING SHOWERS/STORMS AND THIS COMBINED WITH SATURATED SOILS ALREADY WILL ELEVATE THE THREAT FOR LOCALIZED FLOODING. AT THIS TIME THOUGH CONFIDENCE IS TOO LOW TO ISSUE A FLASH FLOOD WATCH AT ANY ONE LOCATION...BUT THE THREAT IS HIGH ENOUGH THAT IT WARRANTED A SEE TEXT IN WPC EXCESSIVE RAINFALL OUTLOOK. TEMPERATURES WILL ALSO CONTINUE ON THE COOL SIDE WITH THE CHILLY PATTERN AS UPPER LOW MOVES OVERHEAD LATE TONIGHT INTO THURSDAY MORNING. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... BY 00Z THURSDAY...THE DEEP LOW PRESSURE SYSTEM WILL BEGIN TO EXIT THE AREA TO THE EAST. BACK AROUND PCPN WILL KEEP POPS GOING ACROSS THE AREA. THE NAM SHOWS SFC CAPE REACHING 1000 J/KG ON THURSDAY. THEREFORE CODED THUNDER WHERE CAPE IS 1000 J/KG OR GREATER. PCPN ACTIVITY WILL BE CONCENTRATED OVER THE HIGHER ELEVATION AND WESTERN SLOPES INTO 12Z FRIDAY. THE ATMOSPHERE WILL REMAIN UNSTABLE FRIDAY...BUT PCPN ACTIVITY WILL DIMINISH IN COVERAGE AS RAINFALL MOVE OVER THE EASTERN MOUNTAINS BY 06Z. THE NAM SHOWS SFC CAPE VALUES INCREASING FROM THE NORTH TO 1200 J/KG AND SINKS SOUTH TO THE REST OF THE AREA THURSDAY AFTERNOON AND EVENING.. THUNDER POTENTIAL SHOULD BE SOMEWHAT DIURNALLY DRIVEN. PRECIPITABLE WATER VALUES SHOULD BE LOWER THAN 0.750 INCHES...SO THAT SHOULD LIMIT THE QPF A BIT. WENT WITH THE SUPERBLEND GUIDANCE FOR TEMPERATURES THROUGH THE PERIOD. && .LONG TERM /SATURDAY THROUGH TUESDAY/... USED AN BLEND OF THE OPERATIONAL MODELS AND ENSEMBLE MEANS FOR FRIDAY NIGHT INTO SATURDAY. THIS HAS THE UPPER LOW MOVING OFF TO THE EAST FRIDAY NIGHT. A WARM FRONT THEN PUSHES NORTHWARD THROUGH THE AREA ON SATURDAY...FOLLOWED BY ANOTHER COLD FRONT ON SUNDAY. FOR THE BEGINNING OF THE WORK WEEK...TRANSITIONED TO A BLEND OF THE ECMWF...CANADIAN...AND ECMWF ENSEMBLE MEAN. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
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WIDESPREAD MVFR CEILINGS THIS MORNING WILL SLOWLY LIFT THROUGH THE DAY. MVFR MORNING CIGS MAY PERSIST UNTIL LATER THIS AFTERNOON...BUT STILL NOT CERTAIN THAT WILL BE THE CASE AS FRONT APPROACHES LATER TODAY. A COLD FRONT WILL BRING SHOWERS AND THUNDERSTORMS BY LATE AFTERNOON AND EARLY THIS EVENING AND POSSIBLY A RETURN TO MVFR OR IFR CONDITIONS IN SHOWERS AND THUNDERSTORMS. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z THURSDAY... FORECAST CONFIDENCE: LOW TO MEDIUM. ALTERNATE SCENARIOS: CIGS WILL TEND TO VARY THROUGH THE MORNING HOURS. HOW LONG MVFR CEILING LAST IIS STILL UNCERTAIN AT THIS TIME...AND HOW LOW CIGS AND VIS FALL LATE THIS AFTERNOON AND THIS EVENING IN SHOWERS AND STORMS IS STILL UP IN THE AIR. THE TIMING OF SHOWERS AND THUNDERSTORMS ARRIVING FROM THE WEST ON THIS AFTERNOON MAY ALSO VARY AS MODELS STILL DIFFER. THUNDERSTORMS MAY BRING IFR CONDITIONS AND CONTAIN SMALL HAIL OR GRAUPEL WEDNESDAY AFTERNOON. 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 10 11 12 13 14 15 16 17 18 19 20 21 EDT 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17 CRW CONSISTENCY M M M M M M M H H H H H HTS CONSISTENCY M M M M H H H H H H M M BKW CONSISTENCY L L L L M M M M M H H H EKN CONSISTENCY L L L M M M M H M H H H PKB CONSISTENCY M M M M M M H H H H H H CKB CONSISTENCY M L L M M M M H M H H H AFTER 12Z THURSDAY... IFR POSSIBLE IN SHOWERS THROUGH THURSDAY AFTERNOON.
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&& .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...ARJ/MPK NEAR TERM...MPK SHORT TERM...ARJ LONG TERM...RPY AVIATION...MPK

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