Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 031900
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
300 PM EDT TUE MAY 3 2016

.SYNOPSIS...
UPPER LEVEL TROUGH CROSSES THIS AFTERNOON AND EVENING WITH SCATTERED
SHOWERS. LARGE UPPER LEVEL LOW BRINGS COOL AND UNSETTLED WEATHER
FOR WEDNESDAY THROUGH FRIDAY.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
THE GENERAL UPPER TROUGHING OVER THE OHIO VALLEY IS KEEPING
WIDELY SCATTERED TO SCATTERED SHOWERS OVER THE AREA THIS
AFTERNOON...BUT THESE ARE MAINLY FOCUSED NEAR THE DISSIPATING COLD
FRONTAL BOUNDARY ACROSS CENTRAL WV. ONE DEFINED VORT MAX SEEN IN
THE CLOUD FIELDS OVER EASTERN KENTUCKY...IN COMBINATION WITH DIURNAL
HEATING...IS MOST LIKELY RESPONSIBLE FOR THE AFTERNOON SHOWERS. THIS
FEATURE WILL SLOWLY MOVE EAST THROUGH TONIGHT...BUT WITH THE LOSS OF
THE DIURNAL FACTOR...EXPECT SHOWERS TO MOSTLY DISSIPATE THIS
EVENING...A BIT LATER IN THE MOUNTAINS. OTHERWISE...STILL LOTS OF
MOISTURE HANGING AROUND UNDER THE GENERAL UPPER TROUGHING THROUGH
TONIGHT...WHICH WILL LIKELY TRANSLATE INTO WIDESPREAD CLOUDS. FOG
LATER TONIGHT WITH THE WET GROUNDS MAY BE ENHANCED BY ANY BREAKS IN
THE CLOUDS...AND NEAR CALM WINDS UNDER WEAK HIGH PRESSURE BUILDING
OVER THE AREA. IN SUMMARY...WILL END SHOWERS EARLY TONIGHT...KEEP
LOTS OF CLOUDS...AND THROW IN SOME RIVER VALLEY FOG LATER TONIGHT.

FOR WEDNESDAY...THE HIGH SHIFTS EAST EARLY WITH SOUTHWEST WINDS
PICKING UP AHEAD OF AN APPROACHING COLD FRONT. THE GFS IS AGAIN THE
FAST OUTLIER...SO WILL ACTUALLY KEEP THE FRONT JUST WEST OF THE AREA
UNTIL NEAR 00Z. HOWEVER...A WELL DEFINED BAND OF SHOWERS ALONG AND
AHEAD OF THE FRONT WILL MOVE INTO THE WESTERN HALF OF THE AREA
DURING WEDNESDAY AFTERNOON. GOING WITH HIGH POPS WITH THIS
FEATURE...AND WITH INSTABILITY AND LOWERING FREEZING LEVELS WITH ITS
ASSOCIATED UPPER LOW DROPPING SOUTH FROM THE GREAT LAKES...HAVE
INSERTED SMALL HAIL FOR THE AFTERNOON IN THE BAND OF SHOWERS/STORMS.
FOR NOW...NOT ANTICIPATING WATER PROBLEMS WITH THE COLD FRONT
SHOWERS NOR ANY SEVERE THUNDERSTORMS.

TEMPERATURES WILL CONTINUE ON THE COOL SIDE WITH THE CHILLY PATTERN.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
AN UPPER LEVEL LOW PRESSURE SYSTEM AND A COLD FRONT WILL AFFECT THE
AREA WEDNESDAY WITH SHOWERS AND THUNDERSTORMS. THE ACTUAL FRONT
CROSSES THE OH RIVER BY 00Z THURSDAY. SO...CONVECTION AHEAD OF THE
FRONT SHOULD AFFECT THE AREA WEDNESDAY AFTERNOON INTO THE EVENING.

BEHIND THE FRONT...COOLER AIR FILTERS IN LATE WEDNESDAY.
HOWEVER...THE ASSOCIATED UPPER LEVEL LOW CROSSES THURSDAY TO
CONTINUE CHANCES FOR RAIN SHOWERS THROUGH THURSDAY. THE UPPER LOW
WILL THEN CREATE UNSTABLE AIR WITH ROUNDS OF SHOWERS THROUGH FRIDAY.
WITH SOME AFTERNOON HEATING...LOW TOP THUNDERSTORMS WITH SMALL HAIL
ARE POSSIBLE THURSDAY AFTERNOON.

USED THE SUPERBLEND GUIDANCE FOR TEMPERATURES THROUGH THE PERIOD.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
USED AN ENSEMBLE MEAN BLEND FOR THE FORECAST DUE TO SPREAD IN THE
OPERATIONAL MODELS AND A PATTERN TRANSITION. THIS BRINGS IN SOME
DRIER AIR FOR SATURDAY. MOISTURE RETURNS ON SUNDAY AS ANOTHER FRONT
PUSHES INTO THE REGION WITH MOISTURE REMAINING INTO THE BEGINNING OF
THE WORK WEEK.

&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
18Z TUESDAY THRU 18Z WEDNESDAY...
LOOKS LIKE WEAK COLD FRONTAL BOUNDARY AT 18Z EXTENDING FROM A
CKB-CRW-HTS-CVG LINE HAS JUST ABOUT LOST DEFINITION AS WINDS
TURNS NORTHWESTERLY AT 5 TO 10 KTS...BUT THE SCATTERED SHOWERS
THAT HAVE DEVELOPED THIS AFTERNOON LOOK TO BE QUITE FOCUSED ALONG
THIS DISSIPATING BOUNDARY....MAINLY AFFECTING HTS AND CRW. WE
LOOK FOR THE SCATTERED SHOWERS TO CONTINUE THIS AFTERNOON...BUT
RAPIDLY DISSIPATE OUTSIDE THE MOUNTAINS BY 00Z...AND BY 04Z IN THE
MOUNTAINS. THE SLOW EASTWARD MOVING UPPER DISTURBANCE OVER
KENTUCKY AND ASSOCIATED WEAK COLD ADVECTION ALOFT WILL KEEP LOTS
OF CLOUDS IN THRU 18Z WEDNESDAY. MIXING DUE TO DIURNAL HEATING IS
HELPING TO LIFT THE ONGOING MVFR CEILINGS...AND WILL BE MAINLY VFR
CEILINGS BY AROUND 21Z. HOWEVER...LOCALLY MVFR CONDITIONS IN THE
SCATTERED AFTERNOON SHOWERS CAN BE EXPECTED.

FOR TONIGHT...GOING WITH MVFR CEILINGS IN LOWLANDS AND IFR
CEILINGS IN MOUNTAINS TO RETURN BY 06Z...AS WEAK HIGH PRESSURE
BUILDS OVER THE AREA. FOG IS A BIG PROBLEM LATER TONIGHT...WHICH
DEPENDS ON HOW MANY BREAKS IN THE CLOUDS OCCUR AND HOW MUCH THE WINDS
DECOUPLE. WILL GO CONSERVATIVE FOR NOW ON THE FOG THINKING THERE
WILL BE A WIDESPREAD CEILING....BUT INSERTING SOME MVFR
CONDITIONS IN THE TAFS 05Z TO 12Z.

AFTER 12Z...HIGH PRESSURE SHIFTS EAST AND SOUTHWEST WINDS PICK
UP...IMPROVING TO VFR BY 15Z LOW LANDS...AND BY 18Z MOUNTAINS.
RAIN SHOWERS WITH NEXT COLD FRONT WILL REMAIN WEST OF THE OHIO
RIVER PRIOR TO 18Z.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z WEDNESDAY...


FORECAST CONFIDENCE: LOW.

ALTERNATE SCENARIOS: MODELS SHOW SOME INSTABILITY ON FORECAST
SOUNDINGS UNDER THE AFOREMENTIONED UPPER DISTURBANCE THRU 12Z
TUESDAY MORNING...AND NOT MUCH OF A LOW LEVEL TEMPERATURE
INVERSION. SO CONFIDENCE IS LOW ON THE WIDESPREAD MVFR/IFR
CEILINGS AND FOG REFORMING 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       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  M    M    M    H    H    H    H    H    H    H    H    M
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
BKW CONSISTENCY  M    M    M    M    M    H    H    H    M    M    M    M
EKN CONSISTENCY  M    M    M    H    H    H    H    H    M    M    M    M
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    M    M

AFTER 18Z WEDNESDAY...
IFR POSSIBLE IN THUNDERSTORMS WEDNESDAY AND THURSDAY AFTERNOONS.

&&

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

&&

$$
SYNOPSIS...ARJ/JMV/MPK
NEAR TERM...JMV
SHORT TERM...ARJ
LONG TERM...RPY
AVIATION...JMV



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