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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