504
FXUS61 KRLX 150539
AFDRLX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
139 AM EDT SUN SEP 15 2019
SYNOPSIS
COOLER, DRIER AIR PUSHES IN TONIGHT, AHEAD OF HIGH PRESSURE FOR
SUNDAY. COLD FRONT CROSSES MONDAY INTO MONDAY NIGHT. HIGH
PRESSURE BUILDS MID WEEK. UPPER LEVEL RIDGE BUILDS LATE WEEK.
NEAR TERM /THROUGH TODAY/
AS OF 1035 PM SUNDAY...
DEW POINTS HAVE RECOVERED SLIGHTLY. SMALLEST DEPRESSIONS WERE
ACROSS THE NORTH, WHERE RIVER VALLEY FOG IS LIKELY TO START
FORMING FIRST.
AS OF 820 PM SATURDAY...
COLD FRONT HAS PUSHED ON THROUGH, TAKING CONVECTION WITH IT.
COOLER AND ESPECIALLY DRIER AIR WAS QUICKLY FILTERING IN BEHIND
THE FRONT, WITH DEW POINTS WELL DOWN IN THE 50S, EVEN THE UPPER
40S IN SPOTS. BLENDED IN HIRES MODEL FORECAST DATA FOR LOWER
TEMPERATURES AND ESPECIALLY DEW POINTS OVERNIGHT, WITH LOWER DEW
POINTS ALSO FOR MONDAY, THE CHANGE MAINLY FOR EASTERN PORTIONS
OF THE FORECAST AREA BY MONDAY AFTERNOON.
AS OF 133 PM SATURDAY...
SFC FRONT IS CURRENTLY BISECTING TO CWA FROM NE TO SW...FROM
NEAR CLARKSBURG TO CHARLESTON TO JACKSON, KY. SCATTERED
THUNDERSTORMS ARE DEVELOPING TO THE EAST OF THE FRONT,
COINCIDENT WITH AN INSTABILITY AXIS. CONVECTION SHOULD SHIFT ENE
THROUGH THE AFTERNOON, BECOMING MORE CONFINED TO THE NE
MOUNTAINS...AND EVENTUALLY SHIFTING EAST OF OUR AREA OF
RESPONSIBILITY. SPC HAS INDICATED THERE IS A MARGINAL RISK OF
SEVERE WEATHER FOR THE NE MOUNTAINS AS AN ISOLATED STRONG STORM
MAY OCCUR, WITH LOCALLY STRONG WIND GUSTS BEING THE PRIMARY
THREAT. HOWEVER, THE THREAT SHOULD BE VERY LOCALIZED.
AFTER THE FRONT PUSHES EAST, DRIER LOW LEVEL AIR SHOULD
GRADUALLY SPREAD INTO THE REGION. THIS WILL RESULT IN MAINLY
CLEAR SKIES TONIGHT ALONG WITH DECOUPLING OF THE LOW LEVEL WIND
FIELDS. AREAS OF RIVER VALLEY FOG MAY DEVELOP LATE TONIGHT,
ESPECIALLY GIVEN THE COOLER LAND TEMPERATURES. MIN TEMPS
TONIGHT SHOULD BE NOTICEABLY COOLER THAN PREVIOUS NIGHTS, GIVEN
THE DRIER AIRMASS PROG TO BE IN PLACE.
CRISP BLUE SKIES ARE EXPECTED ON SUNDAY WITH A VERY DRY
ATMOSPHERIC PROFILE EXISTING. TEMPS WILL LIKELY BE VERY WARM,
HOWEVER, AS THE DRY AIRMASS AND HIGH HEIGHT FIELDS WILL PROMOTE
STRONG SUBSIDENCE.
SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/
AS OF 210 PM SATURDAY...
FOR SUNDAY NIGHT INTO MONDAY, RAINSHOWERS TO THE NORTH OF THE
AREA, COURTESY OF A WEAK LOW PRESSURE SYSTEM, SHOULD QUICKLY
DRY OUT WITH THE HELP OF NORTHERLY FLOW AND A SURFACE HIGH
PRESSURE PROG TO MOVE OVER THE AREA FROM THE SOUTHWEST. A BROAD
UPPER LEVEL RIDGE BUILDS IN THROUGH THIS PERIOD REINFORCING
NORTHWESTERLY FLOW AND DRIER AIR OVER THE REGION FURTHER
PROMOTING FAIR WEATHER AND WARM TEMPERATURES INTO THE BEGINNING
OF THE NEW WORK WEEK.
LONG TERM /TUESDAY THROUGH SATURDAY/
AS OF 220 PM SATURDAY...
THIS PERIOD WILL MAINLY BE UNDER THE INFLUENCE OF THE
AFOREMENTIONED HIGH PRESSURE RIDGE. HOWEVER, THE RIDGE DOES
FLATTEN TOWARDS THE END OF THIS PERIOD MAKING THE AREA
SUSCEPTIBLE FOR SHOWERS AND STORMS DURING THE START OF THE
WEEKEND AS A SYSTEM IS FORECAST TO APPROACH FROM THE WEST.
MODELS ARE HIGHLY IN DISAGREEMENT ON TIMING SO DECIDED TO LEAVE
OUT CHANCE POPS AND GO WITH THE MODEL BLENDED GUIDANCE WHICH
MAKES THIS PERIOD A DRY SPELL. TEMPERATURES WILL REMAIN ABOVE
NORMAL FOR THIS TIME OF YEAR AND WE CANNOT RULE OUT AFTERNOON
THUNDERSTORMS IN THIS PERIOD ALTHOUGH WITH HIGH PRESSURE AND DRY
AIR ANY DEVELOPMENT WILL MOST LIKELY BE ISOLATED IN NATURE.
AVIATION /04Z SUNDAY THROUGH THURSDAY/
AS OF 133 AM SUNDAY...
HIGH PRESSURE IN CONTROL OF WEATHER CONDITIONS THROUGH THE
PERIOD. COOLER AND DRIER AIR BEHIND THE FRONT, COMBINED WITH
WARM RIVER WATER WILL RESULT IN IFR/LIFR RIVER VALLEY FOG
OVERNIGHT. AREAS MOST LIKELY TO BE AFFECTED WILL BE EKN AND PKB
STARTING AROUND 08Z. DENSE FOG COULD ALSO IMPACT CKB AND HTS
DURING THE PREDAWN HOURS. OTHERWISE VFR CONDITIONS WILL PREVAIL
OUTSIDE RIVER VALLEYS. ANY FOR WILL QUICKLY DISSIPATE BY
12-13Z.
CALM FLOW OVERNIGHT TURNING LIGHT AND VARIABLE SUNDAY. LIGHT
WEST TO NORTHWEST FLOW ALOFT TONIGHT WILL BECOME LIGHT NORTH BY
SUNDAY MORNING, AND THEN LIGHT AND VARIABLE TO LIGHT SOUTH
SUNDAY AFTERNOON.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z MONDAY...
FORECAST CONFIDENCE: MEDIUM OVERNIGHT INTO SUNDAY MORNING,
OTHERWISE HIGH.
ALTERNATE SCENARIOS: FOG SEVERITY OVERNIGHT MAY NOT BE AS BAD
AS TAFS CURRENTLY 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.
DATE SUN 09/15/19
UTC 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14
EDT 1HRLY 23 00 01 02 03 04 05 06 07 08 09 10
CRW CONSISTENCY H H L L M M M M M M L H
HTS CONSISTENCY H H H H L L M M M M L H
BKW CONSISTENCY M M L L L L L L L L L H
EKN CONSISTENCY M M M M M M M M M M M M
PKB CONSISTENCY H H M L M M M M M M L H
CKB CONSISTENCY H H L L M M M M M M L H
AFTER 06Z MONDAY...
EARLY MORNING DENSE RIVER VALLEY FOG POSSIBLE MONDAY MORNING.
RLX WATCHES/WARNINGS/ADVISORIES
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
SYNOPSIS...RH/TRM/JZ/RG
NEAR TERM...RH/TRM
SHORT TERM...JZ
LONG TERM...JZ
AVIATION...ARJ
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