Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 021034 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 617 AM EDT TUE SEP 2 2014 .SYNOPSIS... FRONTAL SYSTEM TODAY WITH SHOWERS AND STORMS...SOME STRONG. VERY WARM AND HUMID THROUGH THE END OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... 6 AM UPDATE. TWEAKED POPS INTO LIKELY FOR FAR NORTHWEST ZONES THIS MORNING...ALSO EXPANDED LOW POPS EARLY THIS MORNING INTO NORTH CENTRAL WV...ALL PER RADAR TRENDS. PREVIOUS DISCUSSION... EVEN THOUGH WE ARE TRANSITIONING INTO THE COOL SEASON...THE PATTERN STILL SHOWS SIGNS OF SUMMER AS STRONG UPPER RIDGING HOLDS ACROSS THE SOUTHERN PART OF THE NATION. THIS KEEPS OUR AREA IN THE SOUTHERN EDGE OF THE WESTERLIES WHICH HAS IMPLICATIONS ON ANY FRONT AFFECTING US. MODELS AGREE ON A STOUT UPPER TROUGH OVER THE MID MISSISSIPPI VALLEY LIFTING NORTHEASTWARD ACROSS THE NORTHERN OHIO VALLEY TODAY AND ON INTO NEW ENGLAND TONIGHT...WITH A VORT LOBE TRAILING SOUTH ACROSS OUR AREA. HOWEVER...THE ASSOCIATED COOL FRONT IS WEAK AND WILL LOSE DEFINITION AS IT TRIES TO DROP SOUTHEAST ACROSS THE AREA THIS AFTERNOON AND EVENING. IT APPEARS THE FRONT ITSELF WILL HAVE LESSER IMPACT ON OUR WEATHER. THE GREATEST IMPACT WILL COME FROM THE UPPER TROUGH DYNAMICS IN THE FORM OF A WELL DEFINED RIGHT ENTRANCE REGION OF THE UPPER JET AND THE TRAILING VORT LOBE. WITH PW`S AROUND 2 INCHES AND A MODEST 850 MB SOUTHWESTERLY JET COINCIDING WITH THE UPPER DYNAMICS...WE EXPECT A BAND OF STRONG THUNDERSTORMS TO MOVE ACROSS THIS AFTERNOON AND EVENING. SPC DOES HAVE THE NORTHWEST HALF OF OUR AREA IN A SLIGHT RISK FOR SEVERE THUNDERSTORMS...SO WILL ADD GUSTY WINDS AND SMALL HAIL FOR NOW TO THE WEATHER THIS AFTERNOON. TIMING OF THE STORMS IS BASED ON GOOD MODEL AGREEMENT...REACHING THE OHIO RIVER AROUND 18Z AND PROGRESSING TO THE MOUNTAINS BY 22Z. THINGS QUICKLY WIND DOWN THIS EVENING AS THE UPPER TROUGH PULLS AWAY AND LOSS OF HEATING...LEAVING ONLY THE FAR SOUTHEAST WITH A SLIGHT CHANCE FOR SHOWERS BY MIDNIGHT. LEANING ON LOWER SIDE OF GUIDANCE FOR MAX TEMPS NORTHWEST AND HIGHER SIDE SOUTHEAST DUE TO CLOUDS AND CONVECTION. FOR TONIGHT...SURFACE FRONT BY THIS TIME IS ILL DEFINED AT BEST AS WEAK HIGH PRESSURE TAKES OVER. LOOKS LIKE ANY DRIER AIR THAT MAKES IT INTO THE NORTH AND WEST WILL NOT GET ANY FARTHER. SO WITH LOSS OF WIND FLOW AND DECREASING CLOUDS...EXPECT A GOOD DEAL OF RIVER AND VALLEY FOG TONIGHT...EVEN UP NORTH AND WEST AS BETTER RADIATIONAL COOLING WILL COMPENSATE FOR ANY LOSS OF MOISTURE. TEMPS TONIGHT WILL BE A BLEND OF GUIDANCE. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY/... STRONG UPPER LEVEL RIDGE OVER THE DEEP SOUTH PROVES TO BE PERSISTENT AND STILL WILL NOT BE ABLE TO SHAKE THE 590DKM LINE THROUGH THE END OF THE WEEK. DESPITE THE SURFACE HIGH PRESSURE BUILDING IN WEDNESDAY...THINK WE WILL HAVE ENOUGH LOW LEVEL MOISTURE TO POP ISOLATED SHOWERS/STORMS DURING THE DAYTIME HEATING HOURS. STRETCHED THE SLIGHT CHANCE POPS THROUGH THE ENTIRE CWA BASED ON THIS REASONING. LEFT THURSDAY LARGELY DRY AS IN THE PREVIOUS FORECAST...WITH THE MOUNTAINS AND TUG VALLEY IN THE SLIGHT CHANCE AREA AS BEFORE. NAM BRINGS A WEAK TROUGH AXIS ALOFT OVER THE NORTHWESTERN ZONES IN SOUTHEAST OHIO...BUT COLUMN WILL LIKELY BE TOO DRY AT THIS POINT FOR ANYTHING OF SIGNIFICANCE TO DEVELOP. BRING THE POPS BACK IN AS THE NEXT SYSTEM APPROACHES...AND FIGURE TO GET SOME BETTER DESTABILIZATION DURING THE DAY WITH PRESSURE FALLS. KEEP THE HIGH TEMPERATURES THROUGH THE PERIOD UNDER THE 90 DEGREE MARK GIVEN THE TIME OF YEAR AND MOIST GROUND. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... HEATING BACK UP...AS THE SOUTHERN 500 MB RIDGE BUILDS BACK NORTH FOR FRIDAY. SOME AFTERNOON CONVECTION COULD OCCUR FRIDAY...BUT POPS MOSTLY 20 AND 30 PERCENT. PER WPC MEDIUM COORDINATION...CONTINUE TO TREND SLOWER THAN THE GFS ON THE NEXT FRONT. 12Z GFS QUICKLY DRIES OUT OUR NORTHERN COUNTIES SATURDAY EVENING INTO SUNDAY. PREFER THE SLOWER ECWMF SOLUTION AT THIS TIME...INCREASED POPS INTO LIKELY CATEGORY ON SATURDAY INTO SATURDAY EVENING. HOLDING SOME CHANCE POPS EVEN INTO SUNDAY MORNING FOR NORTHERN COUNTIES...AND INTO SUNDAY NIGHT FOR SOUTHERN COUNTIES. DRY MONDAY...EXCEPT AGAIN SOME SLIGHT CHANCE POPS ALONG THE EASTERN SLOPES. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... 12Z TUESDAY THRU 12Z WEDNESDAY... A FRONTAL BOUNDARY WILL PUSH INTO THE AREA THIS AFTERNOON AND LOSE DEFINITION AS IT TRIES TO CROSS THE AREA FROM WEST TO EAST LATER THIS AFTERNOON AND EVENING. NEVERTHELESS...EXPECT A LINE OF THUNDERSTORMS TO MOVE ACROSS...MAINLY THIS AFTERNOON AND EVENING. OUTSIDE OF CONVECTION...VFR WILL PREVAIL TODAY. ALSO...SOUTHWEST WINDS AHEAD OF THE FRONT WILL BECOME MODERATE THIS AFTERNOON WITH GUSTS TO NEAR 20 MPH IN SOME LOCATIONS. AFTER 00Z...FRONT CONTINUES TO LOSE DEFINITION AS WEAK HIGH PRESSURE DEVELOPS OVER THE AREA. WITH CLOUDS AND WINDS DECREASING...EXPECTING LIFR RIVER AND VALLEY FOG TO FORM BY 06Z...AFFECTING MOST OF THE MAJOR TERMINALS. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z WEDNESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING OF SHOWERS AND THUNDERSTORMS COULD VARY BY A COUPLE OF HOURS. ONSET OF FOG TONIGHT MAY BE DELAYED IF CLOUDS HANG ON LONGER. 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 11 12 13 14 15 16 17 18 19 20 21 22 EDT 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18 CRW CONSISTENCY H H H H H H H H H M M M HTS CONSISTENCY H H H H H H H H M M M M BKW CONSISTENCY H H H H H H H H H H H M EKN CONSISTENCY H H H H H H H H H H H H PKB CONSISTENCY H H H H H H H H H H H M CKB CONSISTENCY H H H H H H H H H H H H AFTER 12Z WEDNESDAY... IFR IN RIVER AND VALLEY FOG EARLY WEDNESDAY MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...JMV/26 NEAR TERM...JMV SHORT TERM...26 LONG TERM...KTB AVIATION...JMV

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