Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 182320
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
720 PM EDT SAT APR 18 2015

.SYNOPSIS...
INCREASING SOUTHEAST WIND LATE TONIGHT/SUNDAY MORNING. SHOWERS WITH
MID LEVEL DISTURBANCES SUNDAY. A COLD FRONT CROSSING MONDAY HERALDS
COOLER WEATHER. ANOTHER FRONT CROSSES WEDNESDAY NIGHT OR THURSDAY.

&&

.NEAR TERM /THROUGH SUNDAY/...
IN EARLY EVENING UPDATE...WENT A BIT COOLER SUNDAY IN THE SE UPSLOPE
FLOW. DO NOT EXPECT TEMPERATURE TO RISE MUCH...READINGS MAY EVEN
FALL WITH ARRIVAL OF THE SHOWERS OVER THE SOUTHERN MOUNTAINS.

AS THE INITIAL LOW PRESSURE LIFTS NORTH THRU INDIANA SUNDAY...925 MB
FLOW AT 30 TO 40 KNOTS...THEN WEAKENS TOWARD 00Z MONDAY. INCREASED
SURFACE GUSTS. HARD TO FIGURE SURFACE GUSTS IN THE WESTERN
LOWLANDS.  GUSTS MAY DECREASE WITH ONSET ON SHOWERS.

PREVIOUS DISCUSSION...

UPPER LEVEL RIDGING GIVES WAY TO A SOUTHWEST FLOW TROUGH AXIS AND
A WARM FRONT AT THE SURFACE. LOW PRESSURE DEEPENS IN A GENERAL SOUTH
TO NORTH TRACK FROM OHIO/MISSISSIPPI RIVER CONFLUENCE INTO
SOUTHERN MICHIGAN. DEEPER MOISTURE ARRIVES AFTER 06Z...FIRST
HITTING THE TUG FORK VALLEY...AND WILL SPREAD NORTHEASTWARD
THROUGH THE REMAINDER OF TONIGHT AND SUNDAY. HEAVIER RAIN PATCHES
POSSIBLE AS INDICATED BY PASSING AREAS OF LOW LEVEL THETA E
CONVERGENCE.

LOW AND MID LEVEL FLOWS ACROSS THE AREA WILL BE STOUT...WITH A
SOMEWHAT RARE SOUTHEASTERLY LOW LEVEL JET THAT COULD PEAK OUT IN
THE 65KT RANGE. SHEAR PROFILES LOOK QUITE INTERESTING...BUT DRYING
BELOW 900MB IN THE DOWNSLOPING SOUTHEASTERLY FLOW WILL KEEP THE
DEWPOINTS DOWN AND THUS ELIMINATE THE BULK OF THE INSTABILITY.
KEEP THE INSTABILITY CONFINED TO THE TUG FORK VALLEY AREA
AGAIN...AND ONLY HAVE THUNDER MENTIONED IN THIS REGION. ALSO OF
NOTE...FORECAST SOUNDINGS INDICATE PRECIP LOADING AS WELL.

KEPT THE TEMPERATURES UP TONIGHT GIVEN THE CLOUDS AND THE WARM
FRONT...AND DOWN TOMORROW GIVEN THE PERIODS OF SHOWERS/RAIN.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
MODELS CONTINUE THEIR GOOD AGREEMENT ON A LEAD SOUTHERN STREAM UPPER
TROUGH...AND ASSOCIATED WARM FRONT...LIFTING RAPIDLY NORTHEAST
ACROSS THE AREA EARLY SUNDAY NIGHT. THE WIDESPREAD BAND OF SHOWERS
AND PERHAPS A RUMBLE OF THUNDER AHEAD OF THE FRONT WILL MOSTLY END
BY MIDNIGHT. THIS WILL PLACE US IN THE WARM SECTOR SUNDAY NIGHT INTO
MONDAY WITH JUST SCATTERED SHOWERS POSSIBLE...BEFORE A COLD FRONT
WITH A NORTHERN STREAM SHORT WAVE MOVES EAST ACROSS THE AREA DURING
MONDAY. INSTABILITY AND MOISTURE WILL INCREASE AHEAD OF THE COLD
FRONT...LEADING TO A BAND OF SHOWERS AND THUNDERSTORMS WITH THE
FRONT. MOST OF THE ACTIVITY WILL BE TOWARD THE EARLIER PART OF THE
DAY MONDAY...SO THAT SEVERE POTENTIAL WILL BE MOSTLY EAST OF THE
AREA AND POPS ACTUALLY DECREASING FROM WEST TO EAST LATER IN THE
DAY. IN ADDITION...THE SPEED OF THE TWO SYSTEMS LOWERS THE POTENTIAL
FOR FLOODING. TEMPERATURES WILL BE AT OR ABOVE NORMAL UNTIL THE
FRONT COMES ACROSS...WITH A COOLING TREND TUESDAY AS DRY HIGH
PRESSURE BUILDS IN.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
OVERALL...WE LOOK TO BE COOLER THAN NORMAL...ESPECIALLY AT NIGHT
THROUGH THE LONG TERM. BEST CHANCE FOR A FROST/FREEZE LOOKS TO BE
FRIDAY MORNING AFTER A WEAK COLD FRONT PASSES THROUGH WEDNESDAY
NIGHT OR THURSDAY. STUCK PRETTY CLOSE TO WPC FOR POPS/SKY/HIGH
TEMPS. UNDERCUT WPC TEMPS A BIT ON OVERNIGHT LOWS. BOTH GFS AND
ECMWF SHOW 850MB TEMPS BELOW ZERO LATE THIS WEEK INTO THIS WEEKEND.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
CONFIDENCE LOWERED FROM HIGH TO MEDIUM. ONE REASON WAS TRYING TO
DETERMINE SURFACE WIND SPEEDS.  ALSO LOWER CONFIDENCE IN
DETERMINING HOW LOW CEILINGS WILL DROP IN THE SOUTHEAST FLOW DURING
THE RAIN SHOWERS OVER THE SOUTHERN MOUNTAINS AROUND BECKLEY.

STILL CONFIDENCE THAT CEILINGS WILL ONLY DROP INTO THE 3 TO 5 THSD
FT RANGE IN THE WESTERN DOWNSLOPE CORRIDOR AROUND CRW TO CKB AND
EVEN EKN...DURING THE SHOWERS IN THE DAYLIGHT HOURS ON SUNDAY.

THINKING THE INCREASING LOW LEVEL FLOW 06Z TO 12Z SUNDAY WILL REACH
THE GROUND...SO AT THIS DISTANCE IN TIME...DID NOT INCLUDE ANY LOW
LEVEL WIND SHEAR.  THERE MAY BE A FEW HOUR WINDOW FOR LLWS IN PLACES
LIKE CRW AND HTS AROUND DAWN SUNDAY IF WINDS REMAIN JUST OFF THE
SURFACE.

ONLY POSSIBILITY OF THUNDER IS FORESEEN IN THE TRI STATE AROUND
HUNTINGTON AFTER 21Z SUNDAY...WITHIN THE SHARP SW TO NE LOW LEVEL
DEW POINT GRADIENT.  THIS INCLUDES EXTREME SRN OHIO...NORTHEAST
KENTUCKY...AND SOUTHWEST WEST VIRGINIA.

BY 15Z SUNDAY...HAVE IFR CEILINGS DEVELOPING ALONG THE EASTERN
SLOPES INCLUDING THE BKW VCNTY.  WITH THAT FLOW PERSISTING...HAVE
IFR CONTINUING INTO SUNDAY EVENING ALONG THESE EASTERN SLOPES...EVEN
THOUGH PRECIPITATION CHANCES TREND DOWN TOWARD 00Z MONDAY.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z MONDAY...

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS: IF INCREASING LOW LEVEL FLOW DOES NOT REACH
SURFACE...THEY MAY BE A FEW HOUR WIND FOR LLWS HTS-CRW VCNTY AROUND
10 TO 13Z SUNDAY. ALSO...TIMING OF ARRIVAL OF IFR CEILINGS AT
BECKLEY COULD VARY.

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       20   21   22   23   00   01   02   03   04   05   06   07
EDT 1HRLY       16   17   18   19   20   21   22   23   00   01   02   03
CRW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
BKW CONSISTENCY  H    H    H    H    H    H    M    M    M    M    M    M
EKN CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H

AFTER 00Z MONDAY...
IFR POSSIBLE MONDAY IN SHOWERS AND STORMS.

&&

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

&&

$$
SYNOPSIS...JMV/MZ/26
NEAR TERM...KTB/26
SHORT TERM...JMV
LONG TERM...MZ
AVIATION...KTB









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