Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 041859 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 259 PM EDT WED MAY 4 2016 .SYNOPSIS... COLD FRONT SLOWLY CROSSES THE AREA LATER THIS AFTERNOON AND TONIGHT. LARGE UPPER LEVEL LOW BRINGS COOL AND UNSETTLED WEATHER FOR THURSDAY THROUGH FRIDAY. WARM FRONT SATURDAY. ANOTHER COLD FRONT SUNDAY. && .NEAR TERM /THROUGH THURSDAY/...
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MODELS PRETTY MUCH ON THE SAME PAGE NOW WITH THE UPPER LOW DROPPING SOUTH ACROSS KENTUCKY TONIGHT...SLOWLY SWEEPING A COLD FRONT EAST ACROSS THE AREA. THE FRONT WILL LIKELY STALL LATER TONIGHT ON THE LEE SLOPE OF THE MOUNTAINS AS THE UPPER LOW SLOWLY TURNS SEWD THROUGH EASTERN AND NORTH CAROLINA THURSDAY. FOR THE REMAINDER OF THIS AFTERNOON...ENOUGH INSTABILITY AND MOISTURE AHEAD OF THE COLD FRONT TO POP SCATTERED SHOWERS AND THUNDERSTORMS. A FEW STORMS MAY CONTAIN SMALL HAIL WITH THE ANOMALOUSLY LOW FREEZING LEVEL...BUT NOT ENOUGH FOR SEVERE STORMS. A MORE CONCENTRATED BAND OF SHOWERS AND SCATTERED THUNDERSTORMS WILL ACCOMPANY THE COLD FRONT AS IT MOVES INTO SOUTHEAST OHIO AND NORTHEAST KENTUCKY LATER THIS AFTERNOON...WITH SMALL HAIL AGAIN POSSIBLE. CAT POPS WITH THIS PRECIP BAND. ALTHOUGH THE GFS IS COMING MORE IN LINE...SPECIFIC TIMING WILL STILL BE WITH THE SLOWER END OF THE MODEL GUIDANCE AND USED THE NAM FOR DETAILS. BUT ONCE WE LOSE THE HEATING...THE LACK OF SYNOPTIC INSTABILITY HAS THUNDER POTENTIAL RAPIDLY DIMINISHING THIS EVENING AS THE FRONT CONTINUES EAST. THE TRACK OF THE UPPER LOW SUGGESTS A DRY SLOW WILL WORK INTO THE WESTERN HALF OF THE AREA BEHIND THE FRONT...WHILE THE EASTERN HALF OF THE AREA WILL REMAIN IN THE PRECIP WITH THE HANGING FRONT AND WRAPAROUND SOUTHEAST FLOW FROM THE UPPER LOW INCREASING OVER THAT AREA. SO...WILL DECREASE POPS TO CHANCE IN THE WEST FOR MUCH OF TONIGHT...BUT KEEP CAT POPS IN THE EAST. FOR THURSDAY...THE MODELS GENERALLY AGREE MOST OF THE AREA WILL SEE WIDESPREAD SHOWERS WORKING WESTWARD IN THE WRAPAROUND FLOW OF THE UPPER LOW...BUT WITH SOUTHEAST OHIO TRENDING TO IMPROVE DURING THE AFTERNOON AS THE UPPER LOW DRIFTS EAST ACROSS NORTH CAROLINA. TEMPS ARE VERY MARGINAL FOR ANY SNOW IN THE HIGHEST ELEVATIONS OF THE NORTHERN MOUNTAINS THURSDAY MORNING...SO WILL OMIT SNOW THERE. WHILE PW`S ARE NOT IMPRESSIVE...THE WEAK FLOW AND POSSIBLE TRAINING OF SHOWERS AROUND THE UPPER LOW LATER TONIGHT AND THURSDAY GIVE SOME CONCERN FOR WATER PROBLEMS. WILL CONTINUE A MENTION FOR THIS IN THE HAZARDOUS WEATHER PRODUCT UNTIL THE SPECIFIC SETUP OF PRECIP BANDS BECOMES CLEARER. TEMPS TONIGHT AND THURSDAY WILL REMAIN ON THE COOL SIDE OF GUIDANCE.
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&& .SHORT TERM /THURSDAY NIGHT 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 WEDNESDAY/... 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 /19Z WEDNESDAY THROUGH MONDAY/...
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18Z WEDNESDAY THRU 18Z THURSDAY... UPPER LOW AND COLD FRONT ON OUR MENU. SCATTERED SHOWERS AND A FEW THUNDERSTORMS...WITH SMALL HAIL POSSIBLE...WILL BE AROUND THIS AFTERNOON AND EVENING AHEAD OF THE APPROACHING COLD FRONT FROM THE WEST...GENERALLY VFR CEILINGS OUTSIDE OF CONVECTION. A MORE ORGANIZED BAND OF FRONTAL SHOWERS AND STORMS...WITH GENERALLY MVFR CONDITIONS...WILL ENTER SOUTHEAST OHIO AND NORTHEAST KENTUCKY LATER THIS AFTERNOON...BUT LOSS OF HEATING AND LACK OF INSTABILITY WITH THE SYSTEM WILL RAPIDLY DIMINISH THUNDER CHANCES AS THE FRONT CROSSES THE OHIO RIVER EARLY TONIGHT. FOR THE TAFS...JUST MENTIONING VCTS. DRY SLOT WORKING IN BEHIND THE FRONT WILL BRING DRIER CONDITIONS AND VFR CEILINGS IN THE WEST FOR MUCH OF THE NIGHT FOR PKB...HTS AND CRW. BUT FRONT WILL STALL IN THE LEE OF THE MOUNTAINS WITH MVFR/IFR CONDITIONS AND SHOWERS FOR THE EAST...AFFECTING CKB...EKN. BKW ON THE EDGE AND WILL INCLUDE THEM IN THE DRY SLOT. ON THURSDAY...MOST OF THE AREA...INCLUDING ALL MAJOR TAFS SITES...WILL TREND RAPIDLY TO IFR/LIFR WITH WIDESPREAD SHOWERS WRAPPING WESTWARD AROUND THE UPPER LOW...WHICH WILL SET UP TO OUR SOUTH. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z THURSDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING OF WRAPAROUND IFR CONDITIONS MAY VARY. 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 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 M M M M M HTS CONSISTENCY H H M M M M M M M M M M BKW CONSISTENCY M H H H H H H M M M M M EKN CONSISTENCY M H H H H H H H H H H H PKB CONSISTENCY H H H H H H H H H M M H CKB CONSISTENCY M H H H H H H H H H H H AFTER 18Z 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...JMV NEAR TERM...JMV/MPK SHORT TERM...ARJ LONG TERM...RPY AVIATION...JMV

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