Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 200622 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 222 AM EDT WED AUG 20 2014 .SYNOPSIS... MUGGY AIRMASS WITH ROUNDS OF CONVECTION WITH DOWNPOURS. ONE DISTURBANCE CROSSES LATE OVERNIGHT INTO WEDNESDAY. WARM FRONT SETS UP TO OUR WEST WEDNESDAY NIGHT AND MOVES INTO THE AREA ON FRIDAY. && .NEAR TERM /THROUGH TODAY/... 200 AM UPDATE... SYSTEMS MOVING INTO THE MIDDLE OHIO VALLEY EVEN SLOWER. NRN SYSTEM...OVER THE UPPER OHIO VALLEY...MAY STILL GRAZE NRN PORTIONS OF FCST AREA OVERNIGHT INTO WED MORNING...WHILE IT APPEARS SRN SYSTEM OVER LOWER OHIO VALLEY WILL HOLD TOGETHER AND CROSS FCST AREA LATE OVERNIGHT THROUGH MIDDAY WED...LIKELY MAKING FOR A WET MORNING FOR MANY. PREV DISCN... NO BIG CHANCES IN THE LATE EVENING UPDATE FROM THE EARLY EVENING UPDATE. MOST NEAR TERM MODELS STILL SHOW MID LEVEL 500 MB VORT AXIS MOVING UP THE OHIO RIVER VALLEY...REACHING TRI STATE NEAR HTS BY 08Z. STRONGER SUPPORT IN NE OHIO THOUGH. SO DESPITE THE LATE NIGHT HOUR...STILL WANTED TO KEEP POPS RELATIVELY HIGH POPS A LATE SUMMER LATE NIGHT/EARLY MORNING...DUE TO THE MOISTURE LADEN LOW LEVELS. STILL THINKING ENOUGH CLEAR TIME AND LIGHT WINDS FOR FIRST PART OF THE NIGHT...FOR FOG IN THE EASTERN AND SOUTHERN VALLEYS...BUT REDUCE THE FOG WEST OF ELKINS AND WEST AND NORTH OF CHARLESTON. DO NOT HAVE A GOOD FEEL ON HOW MUCH CONVECTION MAY TRY TO DEVELOP 18Z WEDNESDAY INTO THE EARLY EVENING. IN WAKE OF THE MID LEVEL SUPPORT THAT EXITS TO OUR EAST...STILL KEPT SOME CHANCE POPS FOR DIURNAL HEATING AND INSTABILITY. && .SHORT TERM /TONIGHT THROUGH FRIDAY/... THE UNSETTLED WX PATTERN CONTINUES IN THE SHORT TERM. WITH NW FLOW ALOFT...SEVERAL IMPULSES WILL TRACK THRU THE AREA. ROUGH CONSENSUS ON TIMING WITH ONE FIRST HALF OF THURSDAY...A WEAKER ONE LATE THURSDAY NIGHT...AND ONE ON FRIDAY. TRACK WILL DEPEND ON HOW BEEFY THE UPPER RIDGE TO THE W GETS. APPEARS THAT S ZONES APPEAR TO BE IN LINE FOR A COUPLE OF THIS DISTURBANCES. WILL HAVE TO CONTINUE TO MONITOR THIS WITH THE JUICY AIRMASS IN PLACE...DOWNPOURS WILL BE LIKELY AND THUS EVENTUALLY A WORRY FOR WATER PROBLEMS IN AREAS THAT GET HIT REPETITIVELY. WILL MAINTAIN HWO WORDING. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... USED WPC THINKING WITH SOME TWEAKS. NORTHWEST UPPER LEVEL FLOW IS ANTICIPATED THROUGH MUCH OF THE PERIOD...WITH HIGH PRESSURE TRYING TO BUILD IN LATE. AT THE SURFACE...A NW-SE ORIENTED FRONT SHOULD BE LOCATED NEARBY THROUGH MUCH OF THE PERIOD. WPC TEMPS LOOKED GOOD AND WERE GENERALLY USED. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... CLEAR E WITH DENSE VALLY FOG...AS TO THE STRATUS FOG HAT OF TUE MORNING. CLOUD COVER ROLLING IN FROM THE W WILL NIX THE FOG AROUND 08Z CKB AND CRW AND 09-10Z EKN. THE OVERNIGHT INCREASE IN CLOUD IS ON ACCOUNT OF TWO DISTURBANCES MOVING ACROSS THE OHIO VALLEY. ONE MOVING ACROSS THE UPPER OHIO VALLEY AS 06Z APPROACHED MAY IMPACT PKB 09-10Z CKB 11-12Z AND EKN 12-13Z WITH SHOWER AND POSSIBLE THUNDER...ALL THIS GIVEN THE LINE OF SHOWERS AND THUNDERSTORMS ASSOCIATED WITH THE DISTURBANCE EXPANDS SWD OVERNIGHT. SECOND SYSTEM MOVING UP LOWER OHIO VALLEY WILL AFFECT MIDDLE OHIO VALLEY AND THEN CENTRAL APPALACHIANS 12-13Z OHIO RIVER 13-15Z CENTRAL WV AND 16-18Z CENTRAL APPALACHIANS. STRONG TO POSSIBLY DAMAGING WINDS ASSOCIATED WITH THESE STORMS AS 06Z APPROACHED MAY STILL BE STRONG WHEN THE STORMS APPROACH THE OHIO RIVER TOWARD DAWN WED. CONDITIONS WILL IMPROVE TO VFR WED AFTERNOON ONCE THE SECOND BATCH OF CONVECTION ROLLS THROUGH...ALTHOUGH SCATTERED CONVECTION MAY POP LATER WED AFTERNOON...ESPECIALLY E OF THE OHIO RIVER...DRIER AIR ARRIVES W. AREAS OF FOG AND POSSIBLY STRATUS MAY START TO FORM BY 06Z THU...BUT HIGHER CLOUDS ASSOCIATED WITH A WARM FRONT SETTING UP TO THE W MAY STUNT THIS IN THE MIDDLE OHIO VALLEY AFTER 06Z THU. SFC FLOW WILL BE LIGHT SW EXCEPT POSSIBLE STRONG GUSTS FROM THE W TO NW IN THUNDERSTORMS. LIGHT W FLOW ALOFT MAY STRENGTHEN A BIT WED EVENING. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z THURSDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: FOG WILL VARY IN INTENSITY OVERNIGHT AND TIMING OF ITS DISSIPATION WILL VARY. TIMING AND IMPACT OF SHOWERS AND THUNDERSTORMS OVERNIGHT INTO WED MAY VARY. 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 WED 08/20/14 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 L L L M M M M M H M M M HTS CONSISTENCY M M M H H H H M M M M M BKW CONSISTENCY H H H L L M M H H M M M EKN CONSISTENCY L L L L L M M M H M M M PKB CONSISTENCY M M M H H H H H M M M M CKB CONSISTENCY M M M H H H H M M M M M AFTER 06Z THURSDAY... IN THE HUMID ENVIRONMENT...IFR EASILY POSSIBLE IN ANY ROUND OF CONVECTION WED NT THROUGH FRI NT. LATE NIGHT AND EARLY MORNING POST RAIN FOG AND STRATUS ALSO POSSIBLE THROUGH SAT MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...JSH/KTB/ARJ/30/TRM NEAR TERM...KTB/TRM SHORT TERM...30 LONG TERM...JSH AVIATION...TRM

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