Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 071243 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 843 AM EDT TUE JUL 7 2015 .SYNOPSIS... WARMER BREEZES TODAY. COLD FRONT APPROACHES FROM MIDWEST TONIGHT... STALLING NEAR OHIO RIVER WEDNESDAY. FRONTAL OSCILLATES NORTH AGAIN WEDNESDAY NIGHT...THEN SOUTH AGAIN THURSDAY. FLASH FLOOD CONCERNS. && .NEAR TERM /THROUGH TONIGHT/... 845 AM UPDATE...ADDED A SLIGHT CHANCE OF POPS ACROSS SOUTHEAST OHIO THIS MORNING AS SHOWERS ARE ALREADY DEVELOPING. OTHERWISE...NO CHANGES WERE NECESSARY. PREVIOUS DISCUSSION FOLLOWS... DUE TO THE WET GROUND WILL POST A FLASH FLOOD WATCH LATE TODAY INTO WEDNESDAY EVENING...FOR THE MOST VULNERABLE COUNTIES. AS THE EPISODE UNFOLDS MAY BE ABLE TO SUBTRACT...OR EVEN...ADD COUNTIES. COME WEDNESDAY...WE CAN ONLY HOPE...THERE MAYBE TOO MANY SHOWERS/CLOUDS AROUND...SO THE 1 TO 2 HOUR RAIN RATES ARE LOWER...ALLOWING STREAMS TO HANDLE THE RUNOFF. BUT COULD NOT COUNT ON THAT. OVERNIGHT SHOWERS EXITED OUR NE COUNTIES PAST FEW HOURS. EVERY FOG NIGHT IS UNIQUE. THICK VALLEY FOG FORMED BY 03Z IN THE DEEPER VALLEYS OF SOUTHERN WEST VIRGINIA...MOSTLY S AND SE OF CRW. AT FIRST GLANCE...IT LOOKED IDEAL FOR FOG DEVELOPING/SPREADING ELSEWHERE TOO. HOWEVER...BOUNDARY LAYER AND 925 MB FLOW WAS INCREASING. 88D VAD HERE AT RLX WAS 15 KNOTS WHEN WE BEGAN THE GRAVEYARD SHIFT...IT INCREASED TO 20 KNOTS BY 06Z. SO BACKED OFF THE FOG FOR AREAS W-N OF CRW. THE DEEPER VALLEYS E AND S OF CRW SHOULD STILL HAVE FOG TO GREET THE DAWN. DO NOT HAVE A GREAT FEEL ON HOW TODAY UNFOLDS. AM CONCERNED THE WARM AIR ADVECTION IN THE 925 TO 850 MB LAYER MAY FORM A RENEGADE SHOWER EARLY THIS MORNING IN OUR WESTERN COUNTIES...WILL HAVE SOME 20/30 POPS FOR THAT. STILL HARD TO TIME PREFRONTAL CONVECTION INTO THE OHIO VALLEY COUNTIES LATER TODAY INTO THIS EVENING. DID GO A BIT EARLIER...BASED ON NEAR TERM MODEL TRENDS. HOWEVER...BOTH 00Z NAM...GFS...ECMWF WERE NOT THAT QUICK. MAY HAVE MORE CELLULAR CONVECTION AT FIRST...WITH LARGER CLUSTERS MOVING IN 00Z TO 06Z WEDNESDAY...AND HOPE WEAKENING IN RAIN RATES DURING THE NIGHT. DID INCLUDE SOME GUSTY WINDS IN LATE AFTERNOON AND EVENING CONVECTION IN SOUTHEAST OHIO AND THE OHIO RIVER COUNTIES. HAVE DEW POINTS AROUND 70 IN THE LOWLANDS THIS EVENING. WE ARE STILL CONCERNED ABOUT THE FLASH FLOOD HAZARD FOR TONIGHT INTO WEDNESDAY EVENING. WILL CONTINUE IN THE HAZARDOUS WEATHER POTENTIAL AND WILL CONTINUE TO CONTEMPLATE FLASH FLOOD WATCHES. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... A MEANDERING FRONT WILL KEEP THE SHORT TERM ACTIVE. MODELS ALL HAVE SLIGHTLY DIFFERENT TIMING AND PLACEMENT OF THIS FRONT AS IT MEANDERS ACROSS THE AREA IN RESPONSE TO SEVERAL WAVES MOVING ALONG IT. TO START THE PERIOD THE FRONT SHOULD BE JUST TO THE WEST OF THE OHIO RIVER. WHILE CONVECTION WILL SINK SE THROUGH THE CWA ON WEDNESDAY...THE FRONT LOOKS TO ACTUALLY LIFT NORTH AS A WEAK SURFACE WAVE MOVES ACROSS IL/IN. HAVE A LULL IN THE POPS...ALTHOUGH STILL CARRYING SLIGHT CHANCE...ON WEDNESDAY NIGHT AS THE FRONT REMAINS TO THE NORTH. AS THE SURFACE WAVE PASSES TO OUR NORTH THURSDAY...THE FRONT WILL SINK BACK IN THURSDAY AFTERNOON AND LIKELY WASH OUT ACROSS THE FORECAST AREA THURSDAY NIGHT. SOME UNCERTAINTY HERE AS THE NAM LOOKS TO ACTUALLY CLEAR THE FRONT TO THE SOUTH AS HIGH PRESSURE BUILDS OVER THE SOUTHERN GREAT LAKES. THE LOWER RESOLUTION GFS AND ECMWF ARE FAIRLY MUDDY THROUGH THIS TIME...BUT DO HINT AT THE FRONT AT LEAST MAKING IT INTO SOUTHERN CWA. HAVE POPS BEGINNING TO INCREASE AGAIN TOWARD EARLY FRIDAY MORNING AS THE NEXT SURFACE WAVE ORGANIZES TO OUR WEST. IN RESPONSE THE FRONT WILL SHARPEN AND DRIFT BEGIN DRIFTING BACK NORTH BY THE END OF THE PERIOD. PRECIPITABLE WATER VALUES HANGOUT IN THE 2 INCH RANGE ALONG THE FRONT WEDNESDAY. PWATS DIP INTO THE 1.5 INCH RANGE WEDNESDAY NIGHT AS THE FRONT LIFTS FARTHER NORTH...BUT THEN INCREASE BACK TO AROUND 2 INCHES THURSDAY AS THE FRONT SINKS THROUGH. THIS SPELLS ROUNDS OF SHOWERS AND STORMS WITH DOWNPOURS LIKELY IN THUNDERSTORMS AND STRONGER SHOWERS. ALSO HAVE UPPER RIDGE BUILDING THROUGH THE PERIOD WHICH SHOULD SLOW DOWN CELL MOVEMENT SOME. THIS SPELLS POTENTIAL WATER ISSUES. HEAVY RAIN COMING IN WAVES SEPARATED BY DRY PERIODS. && .LONG TERM /FRIDAY THROUGH MONDAY/... A UPPER HIGH LINGERS ACROSS THE SOUTHEASTERN CONUS TO START THIS PERIOD. MODELS AGREE WITH UPPER SHORTWAVE SLIDING ACROSS THE NORTHEAST PERIPHERY OF THE RIDGE TO START THE WEEKEND AND ACROSS THE FORECAST AREA. THIS WILL KEEP THE PATTERN UNSETTLED THROUGH THE WEEKEND WITH SHOWERS AND THUNDERSTORMS. WITH THE GROUNDS ALREADY SATURATED...WILL HAVE TO KEEP A CONTINUED EYE ON WATER CONCERNS. A STRONGER WAVE WILL SLIDE ACROSS THE WESTERN GREAT LAKES AND BEGIN TO BREAK DOWN THE SOUTHEAST RIDGE. THIS WILL ONLY BE REPLACED WITH A TROUGH ACROSS THE EASTERN CONUS. THE STORMY PATTERN LOOKS TO BE MAINTAINED INTO NEXT WEEK. && .AVIATION /13Z TUESDAY THROUGH SATURDAY/... THE THICKER FOG HAS REMAINED MOSTLY IN THE DEEPER MOUNTAIN VALLEYS...MAINLY E AND S OF CRW OVERNIGHT...AS THE BOUNDARY LAYER WINDS INCREASED. THE WARM AIR ADVECTION HAS FORMED A FEW RENEGADE SHOWERS W OF HTS BEFORE DAWN. WILL INSERT A SHOWER POSSIBLE HTS AND PKB THIS MORNING...COULD NOT COMPLETELY RULE OUT THUNDER. STILL HARD TO TIMING ON THE PREFRONTAL CONVECTION INTO THE OHIO VALLEY COUNTIES. DID GO A BIT EARLIER...BASED ON NEAR TERM MODEL TRENDS. HOWEVER...BOTH 00Z NAM AND 00Z GFS WERE NOT THAT QUICK. WILL TRANSITION MORE TO MULTIPLE LAYERS CLOUDS AND SHOWERS 03Z TO 12Z WEDNESDAY...WITH A FEW EMBEDDED THUNDERSTORMS. DESPITE BEING SOUTH OF FRONT...WIDESPREAD VSBY 3 TO 5 MILES FIGURED...LOWER IN ANY HEAVIER PCPN. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z WEDNESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING OF CONVECTIVE ROUNDS ARRIVING BETWEEN 18Z TODAY AND 00Z TONIGHT IN THE WESTERN LOWLANDS COULD VARY. AFTER 12Z WEDNESDAY... IFR POSSIBLE IN SHOWERS AND THUNDERSTORMS NEAR THE FRONTAL BOUNDARY WEDNESDAY INTO THURSDAY. POTENTIAL FOR LOW STRATUS AND FOG AT NIGHT IN THE MUGGY AIR. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FLASH FLOOD WATCH FROM 4 PM EDT THIS AFTERNOON THROUGH WEDNESDAY EVENING FOR WVZ005>011-013>020-024>032-036>040- 046-047. OH...FLASH FLOOD WATCH FROM 4 PM EDT THIS AFTERNOON THROUGH WEDNESDAY EVENING FOR OHZ066-067-075-076-083>087. KY...FLASH FLOOD WATCH FROM 4 PM EDT THIS AFTERNOON THROUGH WEDNESDAY EVENING FOR KYZ101>103-105. VA...NONE. && $$ SYNOPSIS...KTB/MZ NEAR TERM...KTB/SL SHORT TERM...MZ LONG TERM...JB/RPY AVIATION...KTB/26

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