636  
FXUS61 KRLX 211002 AAA  
AFDRLX  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE CHARLESTON WV  
602 AM EDT MON OCT 21 2019  
   
SYNOPSIS
 
 
WARM FRONT TODAY WITH MUCH WARMER CONDITIONS. RAIN TONIGHT INTO  
TUESDAY WITH A COLD FRONT. HIGH PRESSURE BUILDS IN FOR MIDWEEK.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
AS OF 602 AM MONDAY...  
 
ADJUSTED CLOUD COVER AND FOG CONDITIONS SOME BASED OFF CURRENT  
CONDITIONS AND LATEST NEAR TERM GUIDANCE. LLJ IS STARTING TO  
STRENGTHEN, AS NOTED BY IMPROVEMENT IN CEILINGS AND VISIBILITIES  
ACROSS THE SOUTHERN/SOUTHEASTERN CWA...AND ALSO BY KRLX WSR-88D  
VAD VALUES.  
 
AS OF 234 AM MONDAY...  
 
MORNING FOG AND LOW CLOUDS WILL MIX OUT BY MID MORNING (IF NOT  
SOONER) AS A SOUTHEASTERLY LLJ STRENGTHENS IN RESPONSE TO THE  
NEXT STORM SYSTEM APPROACHING FROM THE WEST. THE SOUTHEASTERLY  
LOW LEVEL FLOW WILL TRANSLATE TO AN ADIABATIC WARMING COMPONENT  
TODAY, RESULTING IN A DRYING AND WARMING EFFECT IN THE LOWER  
LEVELS OF THE ATMOSPHERE. THUS, PLENTY OF SUNSHINE IS EXPECTED  
FOR MUCH OF THE DAYLIGHT HOURS (ALTHOUGH MAY EVENTUALLY BECOME  
FILTERED BY THICKENING UPPER LEVEL CLOUDINESS AS THE H25 JET  
SHIFTS INTO A GREATER MERIDIONAL POSITION).  
 
AN ELONGATED LOBE OF VORTICITY IN THE H5 FLOW IS PROG TO ADVECT  
NE ACROSS THE AREA MID/LATE AFTERNOON, WHICH COULD RESULT IN  
SOME PATCHY LIGHT RAIN ACROSS THE E/SE CWA. WILL KEEP TODAY DRY,  
HOWEVER, GIVEN AFOREMENTIONED EXPECTED LOW LEVEL DRYING IN THE  
AFTERNOON.  
 
CHANCES OF RAIN WILL THEN INCREASE FROM WEST TO EAST TONIGHT,  
ESPECIALLY DURING THE SECOND HALF OF THE NIGHT, AS A COLD FRONT  
PUSHES EAST TOWARDS THE AREA. 00Z GUIDANCE SUITES HAVE BACKED  
OFF A BIT ON EXPECTED RAINFALL AMOUNTS, BUT THERE SHOULD STILL  
BE SOME EMBEDDED AREAS OF MODERATE RAINFALL OVERNIGHT. A MINIMAL  
THREAT OF LIGHTNING WILL EXIST, PRIMARILY ASSOCIATED WITH  
FORCING ALONG THE IMMEDIATE SFC FRONT.  
 
BREEZY SOUTHEASTERLY SURFACE WINDS WILL DEVELOP THROUGHOUT TODAY  
AS THE LLJ STRENGTHENS. IT SHOULD BE NOTABLY GUSTY AT TIMES FROM  
MIDDAY THROUGH THE AFTERNOON AS MOMENTUM TRANSFER MAXIMIZES  
DURING THIS TIME FRAME.  
 
MAX TEMPS TODAY WILL BE QUITE WARM FOR AREAS WEST OF THE  
MOUNTAINS. LOCATIONS ACROSS WESTERN WV AND SE OH SHOULD FLIRT  
WITH/EXCEED THE 80 DEGREE MARK FOR AFTERNOON HIGHS. AREAS EAST  
OF THE RIDGES ARE LIKELY TO REMAIN RATHER COOL/CHILLY TODAY AS  
COOLER AIR REMAINS COMPRESSED ALONG THE TERRAIN FROM THE  
PERSISTENT SE FLOW.  
 

 
   
SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/
 
 
AS OF 230 AM MONDAY...  
 
THE COLD FRONT AND ITS ASSOCIATED RAINFALL WILL CONTINUE TO  
PROGRESS EASTWARD AT THE START OF THE SHORT TERM PERIOD. LOW  
PRESSURE DEVELOPING ON THE SOUTHERN EXTENT OF THE FRONT IN THE  
MISSISSIPPI VALLEY WILL SCOOT JUST SOUTHEAST OF WEST VIRGINIA  
TUESDAY, WITH AN ADDITIONAL HALF AN INCH OF RAINFALL EXPECTED  
TO FALL EAST OF THE PIEDMONT. THE BOUNDARY WILL PICK UP SPEED AS  
IT CROSSES THE MOUNTAINS, SPRINTING OUT OF THE FORECAST AREA BY  
THE MIDDLE OF THE AFTERNOON ON TUESDAY.  
 
EXPANDING HIGH PRESSURE OVER THE SOUTHERN GULF STATES WILL PUSH  
THE FRONT FARTHER OFFSHORE, RETURNING CENTRAL APPALACHIA TO  
A QUIET AND DRY SPELL BY MIDWEEK THROUGH FRIDAY MORNING. DURING  
WHICH TIME, AFTERNOON HIGHS WILL HOVER AROUND AVERAGE IN THE  
MID 50S FOR THE MOUNTAINS AND LOW TO MID 60S FOR THE LOWLANDS.  
OVERNIGHT LOWS WILL BE CHILLY ACROSS THE MOUNTAINS, ESPECIALLY  
THURSDAY MORNING WHEN THE BOUNDARY LAYER IS MOST LIKELY TO  
DECOUPLE, WHICH COULD LEAD TO AREAS OF PATCHY FROST IN RANDOLPH  
AND POCAHONTAS COUNTIES.  
 

 
   
LONG TERM /FRIDAY THROUGH SUNDAY/
 
 
AS OF 230 AM MONDAY...  
 
THE FORECAST FOR THE END OF THE WORK WEEK REMAINS UNCERTAIN  
BETWEEN GUIDANCE. THE SURFACE HIGH WILL MIGRATE OVER THE MID-  
ATLANTIC REGION BY THURSDAY AFTERNOON, WHICH GLOBAL MODELS  
AGREE UPON, BUT WHAT HAPPENS BEYOND THAT IS WHERE CONSENSUS GOES  
ASTRAY. THE GFS HAS THE HIGH DEPARTING INTO THE ATLANTIC EARLY  
FRIDAY MORNING, MAKING ROOM FOR A PLUME OF MOISTURE RIDING UP  
INTO THE OHIO VALLEY FROM THE ARKLATEX REGION, SHEARING APART  
IN THE PROCESS, BUT LEADING TO TWO SEPARATE CONCENTRATED AREAS  
OF RAIN ENCROACHING ON THE FORECAST AREA. THE ECMWF AND CANADIAN  
HAVE DRIER SOLUTIONS, WITH THE AFOREMENTIONED HIGH REMAINING  
PARKED OVER THE DELMARVA AREA AND PREVENTING MOISTURE FROM  
MARCHING IN FROM THE CENTRAL PLAINS UNTIL LATER ON IN THE  
WEEKEND. GIVEN THIS SPREAD IN GUIDANCE, HAVE MAINTAINED  
PERSISTENCE FROM CENTRAL GUIDANCE AND WENT WITH A CHANCE OF RAIN  
STARTING FRIDAY MORNING AND LASTING THROUGH THE REMAINDER OF  
THE LONG TERM.  
 

 
   
AVIATION /10Z MONDAY THROUGH FRIDAY/
 
 
AS OF 554 AM MONDAY...  
 
VARIETY OF FLIGHT RULES CURRENTLY EXIST DUE TO AREAS OF FOG AND  
STRATUS. OVERALL TREND THIS MORNING, HOWEVER, WILL BE FOR  
IMPROVEMENT TO VFR ACROSS ALL AREAS BY ROUGHLY MIDDAY (IF NOT  
SOONER). SERLY LLVL FLOW IS CURRENTLY DEVELOPING/STRENGTHENING  
AND THIS SHOULD PROMOTE ERODING OF THE FOG/STRATUS FROM SE TO NW  
THIS MORNING...WITH ONLY SOME PASSING CI FOR THE REMAINDER OF  
THE DAYLIGHT HOURS.  
 
NEXT STORM SYSTEM ADVANCES FROM THE WEST TONIGHT WITH AREAS OF  
RAIN DEVELOPING FROM WEST TO EAST OVERNIGHT. CIG DEVELOPMENT  
WITH MVFR EXPECTED AT TIMES TONIGHT WITH VSBYS POSSIBLY BEING  
REDUCED DURING PERIODS OF HEAVIER PRECIP.  
 
WEAK ESERLY SFC WINDS EARLY IN THE TAF PERIOD BECOMING SERLY 10  
TO 15 KTS MIDDAY/AFTERNOON AND NOTICEABLY GUSTY AT TIMES.  
 
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z TUESDAY...  
 
FORECAST CONFIDENCE: MEDIUM.  
 
ALTERNATE SCENARIOS: IMPROVEMENT OF FOG/CIGS IS RATHER UNCERTAIN.  
RAIN ARRIVAL MAY DIFFER THAN FORECAST THIS EVENING AND  
COVERAGE/DURATION MAY NOT BE AS GREAT AS TAFS INDICATE.  
 
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 10 11 12 13 14 15 16 17 18 19 20 21  
EDT 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17  
CRW CONSISTENCY L L L M H H H H H H H H  
HTS CONSISTENCY L L L H H H H H H H H H  
BKW CONSISTENCY L L L L L H H H H H H H  
EKN CONSISTENCY M M M M L M H H H H H H  
PKB CONSISTENCY L L L M H H H H H H H H  
CKB CONSISTENCY M L L L M H H H H H H H  
 
AFTER 12Z TUESDAY...  
IFR CONDITIONS POSSIBLE WITH RAIN TUES MORNING.  
 

 
   
RLX WATCHES/WARNINGS/ADVISORIES
 
 
WV...NONE.  
OH...NONE.  
KY...NONE.  
VA...NONE.  
 

 
 

 
SYNOPSIS...RH/MEK  
NEAR TERM...RH  
SHORT TERM...MEK  
LONG TERM...MEK  
AVIATION...RH  
 
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