Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 171810 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 144 PM EDT SUN AUG 17 2014 .SYNOPSIS... AN UPPER DISTURBANCE BRINGS WIDESPREAD SHOWER AND STORMS...MAINLY SOUTH LATER TONIGHT AND MONDAY. && .NEAR TERM /THROUGH TONIGHT/... 10 AM UPDATE. NO SIGNIFICANT CHANGES. PREVIOUS DISCUSSION... THE TALE OF THE SPLIT FLOW CONTINUES. UPPER TROUGH/LOW IN NORTHERN STREAM WILL BE PUSHING EASTWARD DURING THE NEAR TERM PERIOD...WHILE ANOTHER UPPER LOW WILL PUSH EAST OUT OF THE MIDWEST/IL/WRN KY AREA INTO OUR REGION. FRONTAL BOUNDARY ASSOCIATED WITH LOW TO THE NORTH WILL STALL OUT ACROSS NORTHERN OHIO/NORTHERN INDIANA TODAY...WHILE A WARM FRONTAL BOUNDARY ASSOCIATED WITH THE LOW TO THE WEST WILL LIFT NORTH ACROSS THE REGION...HELPING TO USHER IN WARMER TEMPERATURES...AND GREATER HUMIDITY. PW VALUES ARE ALREADY INCREASING ACROSS THE AREA...WITH 00Z SOUNDING OUT OF ILN 1.7 INCHES...AND ARE EXPECTED TO INCREASE TO AROUND 1.7 AREA WIDE BY THE END OF THE NEAR TERM PERIOD. THIS WILL HELP TO SET THE STAGE FOR HEAVY DOWNPOURS THROUGH EARLY NEXT WEEK. STILL LOOKING LIKE THE BETTER CHANCES FOR PRECIPITATION LATER THIS MORNING WILL BE ACROSS THE NORTH...WHERE BETTER JET DYNAMICS WILL EXIST. HOWEVER...THERE WILL BE A CHANCE AREA WIDE THIS MORNING...AS A SHORTWAVE ACROSS THE SOUTH MOVES THROUGH THE AREA...EXITING TO THE EAST LATE THIS MORNING. ACTIVITY WILL THEN CONTINUE DURING PEAK HEATING HOURS. MAY SEE A BIT OF A WANE IN THE ACTIVITY LATER TONIGHT...BUT ACTIVITY WILL GRADUALLY START TO RAMP UP AGAIN LATE IN THE PERIOD AS THE UPPER LOW TO THE WEST MOVES INTO THE AREA. THE GREATEST THREAT WITH THE HEAVY RAIN POTENTIAL/WATER ISSUES WILL EXIST AFTER THE NEAR TERM PERIOD...AND THIS WILL BE ADDRESSED IN THE HWO. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... UPPER LEVEL S/W TROUGH AND MODEST SFC REFLECTION CROSS MON AND EXIT MON NT. MODELS HAVE TRENDED TOWARD LESSER AMPLIFIED SYSTEM AND HENCE A MORE SOUTHERN TRACK COMPARED WITH PAST FEW DAYS. THIS MOVES THE MAXIMUM PRECIPITATION FARTHER S WHILE DECREASING THE MAGNITUDE TO THE TUNE OF A NEAR 50 PERCENT REDUCTION. ALL MODELS SHOW AROUND AN INCH OR LESS DURING MON AND MON NT COMBINED...WITH MAXIMUM AMOUNTS GENERALLY ACROSS THE SOUTHERN HALF OF THE FCST AREA. THE SEVERE POTENTIAL IS ALSO LIMITED AS THE FLOW IS PROGGED TO BE LESS...AND THE STRONGEST FLOW NOW PROGGED S OF THE AREA...30 KTS AHEAD OF AND BEHIND THE SYSTEM. INSTABILITY IS LIMITED BY LACK OF HEATING PER WIDESPREAD CLOUD AND PRECIPITATION...AND MID LEVEL LAPSE RATES ONLY AROUND 5C/KM. TUE STARTS OUT WITH STRATUS IN LIGHT AND VARIABLE LOW LEVEL FLOW. THE AREA REMAINS IN WNW UPPER LEVEL SOUTHERN STREAM FLOW. NEXT S/W TROUGH IN THE FLOW DIGS IN LATE TUE AND TUE NT...COUPLED WITH LOW LEVEL WARM ADVECTION AND A 40 KT LOW TO MID LEVEL FEED EARLY ON. THIS GIVES RISE TO THE NEXT CHANCE FOR SHOWERS AND THUNDERSTORMS. TIMING AND TRACK UNCERTAINTY PRECLUDE LIKELY POPS AT THIS TIME...BUT IT APPEARS AN ACTIVE WEEK WILL UNFOLD. WITH LESS POTENTIAL FROM THE MON SYSTEM BUT REPETITIVE SYSTEMS DURING THE WEEK...THE INSERTION OF WATER CONCERNS LATER IN THE WEEK IN THE HWO SAT AFTERNOON SEEMS PRUDENT AND WILL MAINTAIN. ONLY SMALL CHANGES MADE TO HIGHS GIVEN BIAS CORRECTED MET AND LOWS GIVEN BLEND OF BIAS CORRECTED MET AND MAV. CLOUDS AND SHOWERS KEEP HIGHS MON AT OR EVEN A BIT BELOW NORMAL...BUT NIGHTS WILL BE WARM AND MUGGY AS AN INCREASINGLY WARM AND HUMID WEEK UNFOLDS GIVEN H85 TEMPERATURES OF 18-20C AND H85 DEW POINTS OVER 15C BECOMING COMMON. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... RIGHT ON THE HEELS OF THE MON/TUE SYSTEM ANOTHER SYSTEM ARRIVES ON WEDNESDAY MORNING...LUCKILY THE ENERGY QUICKLY LIFTS TO THE NORTH LEAVING DRIBBLES AND DRABS FOR MOST OF WEDNESDAY. ON THURSDAY YET ANOTHER SYSTEM ARRIVES...BUT BY THIS TIME JUST BROAD BRUSHED AREA WITH HIGHER POPS AS TIMING IS LIKELY THROWN OUT THE WINDOW BY THIS TIME IN SUCH AN ACTIVE PATTERN. MODELS CONTINUE TO INDICATE MORE IMPULSES STREAMING THROUGH BY NEXT WEEKEND. RIDGING FINALLY STARTS TO BUILD NEXT SUNDAY. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... 18Z SUNDAY THRU 18Z MONDAY... AN UPPER DISTURBANCE CENTERED OVER SOUTHERN ILLINOIS AT 18Z...WITH A WIDESPREAD AREA OF SHOWERS AND STORMS...WILL MOVE EASTWARD ACROSS OUR AREA LATER TONIGHT AND MONDAY. THRU 01Z...EXPECT SCATTERED SHOWERS AND PERHAPS A THUNDERSTORM IN A MARGINALLY UNSTABLE ATMOSPHERE. OUTSIDE OF CONVECTION...EXPECT PREVAILING CEILINGS AOA 4000 FEET...EXCEPT MVFR IN THE HIGHER ELEVATIONS OF THE NORTHERN MOUNTAINS. AFTER 01Z...THE ABOVE MENTIONED SYSTEM WILL SLOWLY SPREAD THE WIDESPREAD SHOWERS AND STORMS INTO SOUTH AND SOUTHWEST PORTIONS OF THE AREA BY AROUND 06Z...THEN SPREAD NORTHEASTWARD INTO THE NORTHERN MOUNTAINS BY 17Z. THE MOST ORGANIZED AREA OF CONVECTION WILL BE MAINLY ALONG AND SOUTH OF A HTS-CRW-EKN LINE...WHERE VFR CEILINGS EARLY TONIGHT WILL LOWER INTO IFR/LIFR WITH THE RAIN. NORTH AND WEST OF THIS LINE...MAINLY VFR CEILINGS THIS PERIOD WITH SCATTERED SHOWERS AND STORMS. EXPECT THIS TO CONTINUE THRU 18Z.EXCEPT FOR NORTHEAST PORTIONS OF THE AREA...WE DO NOT EXPECT SIGNIFICANT RIVER AND VALLEY FOG TONIGHT. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY... FORECAST CONFIDENCE: LOW TO MEDIUM. ALTERNATE SCENARIOS: TIMING OF SHOWERS/THUNDERSTORMS AND ASSOCIATED MVFR CONDITIONS COULD VARY FROM FORECAST. 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 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 H EKN CONSISTENCY M M H H H H H H H H H H PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY M M H H H H H H H H H H AFTER 18Z MONDAY... IFR POSSIBLE IN POST RAIN STRATUS AND FOG MONDAY NIGHT INTO TUESDAY MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...TRM/JMV/SL NEAR TERM...JMV/SL SHORT TERM...TRM LONG TERM...JW AVIATION...JMV

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