Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 271052 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 640 AM EDT SUN JUL 27 2014 .SYNOPSIS... COLD FRONT WITH STRONG TO SEVERE STORMS TODAY. UPPER LEVEL DISTURBANCES WILL AFFECT THE AREA THROUGH MONDAY...WITH LINGERING CONVECTION. COOLER AND DRIER AIRMASS MID WEEK. && .NEAR TERM /THROUGH TONIGHT/...
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6 AM UPDATE...PUT A RELATIVE MIN IN POPS THIS MORNING BEFORE CONVECTION FARTHER WEST AHEAD OF COLD FRONT AFFECTS US LATER THIS MORNING AND AFTERNOON. ALSO TRENDED FASTER IN LESSENING POPS LATER THIS AFTERNOON AND EVENING...AS MODELS SHOW MID LEVEL DRY SLOT RACING OUT AHEAD OF THE FRONT ITSELF. PREVIOUS DISCUSSION... THE KENTUCKY MESOSCALE THUNDERSTORM COMPLEX THAT SEVERELY DISTORTED THE SYNOPTIC PATTERN YESTERDAY AND LAST NIGHT WILL DISSIPATE THIS MORNING AS IT CONTINUES TO TRACK SOUTH AND EAST INTO LESS FAVORABLE AIR. HOWEVER...THE EVOLUTION OF THE BOUNDARY IT SET UP FROM SOUTHERN INDIANA INTO SOUTH CENTRAL KENTUCKY...EVIDENT IN NEW THUNDERSTORMS EARLY THIS MORNING...WILL BE A KEY FACTOR IN ANY ALTERATION OF THE SYNOPTIC PATTERN FORECAST BY THE MODELS TODAY. THE MODELS CONTINUE TO ADVERTISE THAT THE IMPRESSIVE SYNOPTIC SCALE PARAMETERS AHEAD OF A STRONG COLD FRONT MOVING ACROSS OUR AREA THIS AFTERNOON AND EVENING WILL BE THE MAIN PLAYER. THIS MEANS THE EARLY MORNING CONVECTION ALONG THAT BOUNDARY SHOULD DISSIPATE AS IT TRIES TO MOVE EAST NORTHEAST LATER THIS MORNING INTO WORKED OVER AIR. THIS WILL IN TURN AID THE CONVECTIVELY INDUCED BOUNDARY TO DISSIPATE WITH MIXING OR LIFT IT BACK NORTH AND EAST...ALLOWING THE ATMOSPHERE TO RECOVER AHEAD OF THE COLD FRONT. WITH HPC AND SPC CONTINUING TO GO WITH THE SYNOPTIC THINKING...WE WILL ALSO GO WITH IT WHICH MEANS THAT SEVERE THUNDERSTORM AND FLASH FLOOD POTENTIAL WILL CONTINUE UNTIL THE FRONT EXITS EARLY TONIGHT. THUS...WILL KEEP THE FLASH FLOOD WATCH GOING. WILL KEEP HIGH POPS AND MENTION SEVERE AND WATER IN THE FORECAST UNTIL THE FRONT GO THROUGH. GIVEN THE RICH ATMOSPHERE AND ANY NUMBER OF ADDITIONAL DISTURBANCES AHEAD OF THE MAIN SHOW WITH THE FRONT. BELIEVE THE MODELS MAY BE TOO HIGH ON THE TEMPS TODAY...WILL KEEP HIGHS IN THE MID TO UPPER 80S WITH ALL THE CLOUDS AND CONVECTION. PROBABLY A RELATIVE BREAK IN THE SHOWERS TONIGHT BEHIND THE COLD FRONT...BEFORE YET ANOTHER COLD FRONT SWINGS DOWN MONDAY OUT OF OHIO UNDER THE AMPLIFYING UPPER TROUGH. WILL DECREASE POPS FROM WEST TO EAST FAIRLY EARLY TONIGHT AND DROP THUNDER POTENTIAL...BEFORE POPS RAMP BACK UP LATE.
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&& .SHORT TERM /MONDAY THROUGH WEDNESDAY/... SECONDARY COLD FRONT DROPS IN WITH ANOTHER REINFORCING BATCH OF SHOWERS AND STORMS IN COOLER AIR ALOFT MONDAY AFTERNOON AND EVENING. ADVECTION OF A COOLER AIRMASS AT THE SURFACE OCCURS IN NORTHERLY FLOW AS THICKNESSES DROP INTO THE UPPER 550S WITH SOME SINGLE DIGIT 850MB TEMPERATURES. HIGH PRESSURE INFLUENCES FROM THE NORTHERN PLAINS WILL BECOME THE DOMINANT FEATURE OVER OUR AREA...BUT THE UPPER LEVEL TROUGH OVER JAMES BAY WILL KEEP THE POTENTIAL FOR WEAK LOW PRESSURE SYSTEMS TO DROP THROUGH THE GREAT LAKES. THROUGH THE END OF THE SHORT TERM...THE FORECAST IS PRIMARILY DRY WITH A COOL END TO THE MONTH OF JULY. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... HIGH PRESSURE BEHIND THE COLD FRONT TAKES CONTROL LATER MONDAY NIGHT THROUGH THE MIDDLE OF NEXT WEEK WITH NEAR NORMAL TEMPERATURES. BLENDED HPC WITH PREVIOUS FORECAST NUMBERS AS THEY LOOK REPRESENTATIVE UNDER HIGH PRESSURE AND SLIGHTLY COOLER NORTHERLY FLOW. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/...
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12Z SUNDAY THRU 12Z MONDAY... MVFR/IFR IN CLOUDS/FOG THRU 13Z OVER SOUTHERN HALF OF CWA FROM PREVIOUS CONVECTION...MAINLY AT BKW...OTHERWISE VFR CEILINGS. AFTER 13Z...A STRONG COLD FRONT REACHES THE OHIO RIVER BY 02Z AND THE MOUNTAINS AROUND 06Z. WITH A VERY UNSTABLE ATMOSPHERE AHEAD OF THE FRONT TODAY...MORE THUNDERSTORMS ARE LIKELY AFTER A MINIMUM OF MORNING CONVECTION. BEST TIMING OF THE STORMS WILL BE MORE WITH THE MID LEVEL DRY INTRUSION RATHER THAN THE FRONT ITSELF LATER THIS MORNING AND AFTERNOON...WELL AHEAD OF THE COLD FRONT. SOME OF THE STORMS MAY BE SEVERE. OUTSIDE OF CONVECTION EXPECT VFR CEILINGS. AGAIN...CONVECTION DIMINISHES FROM WEST TO EAST THIS AFTERNOON AND EVENING AHEAD OF THE COLD FRONT AS MID LEVEL DRY INTRUSION OVERSPREADS THE AREA. AFTER 02Z...MVFR CEILINGS GRADUALLY SPREADING SOUTHEASTWARD FROM OHIO...ASSOCIATED WITH COLD ADVECTION AND LOW LEVEL MOISTURE WHICH MAY RESULT IN CONTINUED SCATTERED LIGHT SHOWERS. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z MONDAY... FORECAST CONFIDENCE: LOW ALTERNATE SCENARIOS: TIMING...COVERAGE...AND SEVERITY OF THUNDERSTORMS TODAY MAY VARY...AS WELL AS ONSET OF MVFR CEILINGS 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 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 M M M M M M HTS CONSISTENCY H H H H H H M M M H H H BKW CONSISTENCY H H H H H H H H H H H M EKN CONSISTENCY H M H H H H H H H H H M PKB CONSISTENCY H H H H H H M M M M H H CKB CONSISTENCY H H H H H H H H H M M M AFTER 12Z MONDAY... NO SIGNIFICANT IFR CONDITIONS EXPECTED.
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&& .HYDROLOGY... A SERIES OF UPPER LEVEL DISTURBANCES AHEAD OF A COLD FRONT MAY PRODUCE AREAS OF HEAVY RAINFALL TODAY AND EARLY TONIGHT. AMPLE MOISTURE IN THE LOW LEVELS AND STRONG FORCING ALOFT CAN BE CONDUCIVE TO FLASH FLOODING. THIS SCENARIO COULD PRODUCE FLASH FLOODING OF STREETS...CREEKS...SMALL STREAMS AND LOW LYING AREAS WITH REPETITIVE SHOWERS OR STORMS. A FLASH FLOOD WATCH IS IN EFFECT FROM MIDNIGHT TONIGHT THROUGH LATE SUNDAY NIGHT FOR OUR ENTIRE CWA. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WVZ005>011-013>020- 024>040-046-047. OH...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ066-067-075-076- 083>087. KY...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ101>103-105. VA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR VAZ003-004. && $$ SYNOPSIS...JMV/26 NEAR TERM...JMV SHORT TERM...26 LONG TERM...ARJ AVIATION...JMV HYDROLOGY...JMV

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