806 FXUS61 KRLX 121604 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 1204 PM EDT TUE AUG 12 2014 .SYNOPSIS... LEAD COLD FRONT CROSSES THIS AFTERNOON...THEN ANOTHER COLD FRONT AND UPPER LEVEL TROUGH CROSS TONIGHT. HIGH PRESSURE CROSSES LATE WEEK. && .NEAR TERM /THROUGH TONIGHT/... 11 AM UPDATE. BASED ON LATEST RADAR...SATELLITE AND OBS COMBINED WITH LATEST HI RES MODELS...A LINE OF STRONG THUNDERSTORMS EXPECTED ALONG A COOL FRONT AS IT CROSS FROM WEST TO EAST THIS AFTERNOON AND EARLY EVENING. HAVE ADJUSTED POPS ACCORDINGLY. PREVIOUS DISCUSSION... OVERALL FORECAST IS GENERALLY ON TRACK THIS EARLY MORNING. A SCATTERED BATCH OF SHOWERS WITH A FEW EMBEDDED THUNDERSTORMS STILL PROGRESSING NORTHEAST ACROSS THE NORTHERN QUARTER OR SO OF THE FORECAST AREA...WITH ADDITIONAL SHOWERS ALONG THE EASTERN MOUNTAINS. WATER VAPOR IMAGERY DEPICTING DRY SLOT PRETTY MUCH OVER THE WESTERN HALF OF THE AREA AS WELL. A FEW SHOWERS TRYING TO POP UP FURTHER SOUTHWEST IN EASTERN KY UNDERNEATH THIS DRY AIR. TODAY THE AREA REMAINS UNDER S/SW FLOW ALOFT AS AN UPPER TROUGH CONTINUES TO PROGRESS ACROSS THE GREAT LAKES. ATTENDANT SFC LOW CURRENTLY OVER EASTERN MI WILL MOVE N/NE AROUND THE UPPER LOW...DRAGGING A COLD FRONT TOWARDS THE AREA. NEAR-TERM AND SHORT-TERM MODELS CONTINUING TO INDICATE A PREFRONTAL SCATTERED LINE OF SHOWERS AND THUNDERSTORMS PUSHING ACROSS THE AREA NW TO SE BTWN ROUGHLY 18Z-00Z. IN THE WAKE OF THIS MORNING/S ACTIVITY...LOWERED PRECIP CHANCES FOR CENTRAL AND WESTERN ZONES FOR A TIME THIS MORNING BUT STILL EXPECT A FAIRLY DECENT CHANCE OF PRECIP OVER THE NE ZONES AND INTO THE EASTERN MTNS. NOT SOLD ON A COMPLETE SOLID LINE OF THUNDERSTORMS WITH A GOOD AMOUNT OF DRY AIR ALOFT POTENTIALLY LIMITING COVERAGE...BUT HIGH CHANCE POPS ARE CERTAINLY WARRANTED. A FEW OF THESE STORMS MAY BECOME SEVERE...PARTICULARLY OVER THE NORTH/NORTHEAST ZONES...WITH 0-6K SHEAR INCREASING TO AROUND 40-45KTS. A FAIRLY THIN CAPE PROFILE WILL BE A LIMITING FACTOR AS WELL AS AFOREMENTIONED DRY AIR ENTRAINMENT. SPC HAS PLACED LOCATIONS GENERALLY NORTH AND EAST OF CHARLESTON IN A SLIGHT RISK FOR SEVERE THUNDERSTORMS. WIND WILL BE THE PRIMARY HAZARD...BUT LARGE HAIL CAN/T BE RULED OUT. HEAVY DOWNPOURS ARE POSSIBLE AS WELL. WITH TONIGHT/S RAINS AND LOWERED 1-HR FFG...ISSUED A FLASH FLOOD WATCH FOR THE MOST VULNERABLE AREAS...AGAIN GENERALLY FOR THE NORTHEAST AREAS. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY/... BY WEDNESDAY LINGERING MOISTURE BEHIND THE COLD FRONT COULD STILL PRODUCE LIGHT RAIN SHOWERS OVER THE NORTHEAST COUNTIES THROUGH THE EARLY AFTERNOON HOURS. FRESHER AIR MASS WILL FILTER IN BEHIND THE FRONT UNDER NORTHWEST TO NORTH FLOW. MODELS INDICATE COLD AIR ADVECTION AT H850 DROPPING ABOUT 5 DEGREES. THIS POINTS OUT THAT SOME LOW STRATUS COULD FORM WITH LINGERING MOISTURE AND CAA. FOR TEMPS...WENT WITH THE BIAS CORRECTED MOS FOR TEMPERATURES THROUGH THE PERIOD. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... USED WPC THINKING WITH SOME TWEAKS. HIGH PRESSURE WILL GIVE WAY... ALLOWING A COLD FRONT TO APPROACH THE AREA FROM THE NORTH ON SUNDAY. IT IS TOUGH TO SEE IF THE FRONT ACTUALLY PUSHES SOUTH ACROSS THE REGION OR STALLS ACROSS OUR NORTHERN COUNTIES. AN AREA OF LOW PRESSURE WILL THEN APPROACH FROM THE WEST LATE IN THE PERIOD. WPC TEMPS LOOKED GOOD AND WERE GENERALLY USED. && .AVIATION /16Z TUESDAY THROUGH SATURDAY/... 15Z TUESDAY THRU 12Z WEDNESDAY... MVFR/LOCAL IFR CEILINGS IMPROVING TO LOW END VFR CEILINGS BY 18Z. OTHERWISE...A LINE OF STRONG THUNDERSTORMS ASSOCIATED WITH A COOL FRONT IS EXPECTED TO MOVE RAPIDLY EASTWARD ACROSS THE AREA THIS AFTERNOON AND EARLY EVENING. SOME OF THE STORMS MAY PRODUCE GUSTY WINDS...SMALL HAIL AND HEAVY RAINFALL REDUCING TO CONDITIONS TO LIFR. OUTSIDE OF THUNDERSTORMS EXPECT MAINLY VFR CEILINGS AND VSBY WITH MODERATE SOUTHWEST WINDS. BEHIND THE LINE OF STORMS CLOUDS MAY SCATTER OUT FOR WHILE UNTIL WRAPAROUND MOISTURE WITH A SECONDARY COOL FRONT SWEEPS SOUTH AND EAST ACROSS THE AREA TONIGHT. SO BEGINNING AROUND 02Z WILL SPREAD MVFR CEILINGS BACK ACROSS THE AREA AND CONTINUING THRU 12Z. MAY BE A FOG ISSUE...MAINLY IN THE MOUNTAINS WITH UPSLOPE OF THE LOW LEVEL MOISTURE. HAVE INTRODUCED MVFR FOG IN ALL TAF. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z WEDNESDAY... FORECAST CONFIDENCE: MEDIUM TO HIGH. ALTERNATE SCENARIOS: TIMING OF THE KINE OF STORMS MAY VARY BY AN HOUR OR TWO. MVFR CEILINGS MAY MOVE IN FASTER TONIGHT. 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 14 15 16 17 18 19 20 21 22 23 00 01 EDT 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21 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 M EKN CONSISTENCY H H H H M M M M M M M M 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 18Z WEDNESDAY... SOME IFR CONDITIONS POSSIBLE IN FOG WED MORNING AFTER 12Z. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FLASH FLOOD WATCH UNTIL 11 PM EDT THIS EVENING FOR WVZ008>011- 016>020-028>032-039-040. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...ARJ/JMV/50 NEAR TERM...JMV/50 SHORT TERM...ARJ LONG TERM...JSH AVIATION...JMV/50