Area Forecast Discussion
Issued by NWS Charleston, WV

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FXUS61 KRLX 291845
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
245 PM EDT THU SEP 29 2016

.SYNOPSIS...
A large upper level low will bring unsettled wet weather through
Friday. It pulls away in time to bring dry weather for much of the
weekend. High pressure continues the dry weather early next week.

&&

.NEAR TERM /THROUGH FRIDAY/...
As of 235 PM Thursday... Deep upper low pressure has settled
southward and now remains nearly stationary oscillating over
Northern Kentucky. Low level moisture is fairly low across the
region with dew points in the upper 50s and this should be a
limiting factor for instability. However, visible imagery is
showing some breaks in the cloud cover across parts of our Eastern
forecast area and CAPE values in these areas could approach 1000
J/Kg. With very cold temperatures aloft, lapse rates near 7C/km
and with strong 0-6km bulk shear near 60kts shear, there is
potential for rotating updrafts that could support marginal to
severe hail and even a weak tornado could be possible. SPC
continues to keep the region in a marginal risk...with
southern/eastern WV zones in a 2 percent for tornadoes.

The next threat that we are concerned with this afternoon is for
training of convection across Northeast West Virginia counties
this afternoon and this evening. Convection is starting to line up
across Northern Virginia and should be moving into Pocahontas and
Webster Counties in the next 2 hours. Although flash flood
guidance is relatively high, if training were to persist over the
same area then flash flooding could become an issue. However,
confidence is still too low at this time to issue a Flash Flood
Watch, so for now I will just mention in the HWO.

Weather will remain unsettled tomorrow with the upper level low
still in our vicinity. Expect more showers to develop, mostly
across the Northern Half of the Forecast Area. However, there will
be much more cloud cover so not expecting the diabatic warming we
saw today, so storms will not be strong. Showers will end from
south to north as we head into Friday evening.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
As of 1222 PM Thursday...

Large upper level low over the lower Ohio Valley will move to
northern Indiana by Saturday afternoon and then to the eastern
Great Lakes late.

Showers will be most numerous across northeast portions of the
area early Friday night. However, coverage should quickly
decrease by early Saturday with much of the area getting into the
dry slot.

There could still be a few showers in the northern mountains as
well as portions of northeast Ohio early Saturday night. However,
expect Sunday should be dry across the area.

Used a blend of guidance for lows and highs.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 1205 PM Thursday...

Period will begin with pesky upper low moving away from the
region. Upper level ridge will build in as an upper level trof
approaches from the west. Models differ on the track of Tropical
Storm Matthew. GFS has the system moving along the North Carolina
coast while the ECMWF has it well to the south. Current thinking
is to follow WPC timing which is close to that of the GFS.

End result should be dry weather Sunday night through Tuesday
before the flow around Matthew begins to push some moisture
westward into the mountains. This increasing moisture could
result in some afternoon/evening showers and storms in the
northern mountains Wednesday and Thursday.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
As of 240 PM Thursday...

Upper level low continues to rotate over the region and kicking
off widespread showers and thunderstorms with MVFR to IFR
conditions. After sunset we will see a decrease in showers and
storms...but low IFR stratus may linger through the night as well
as lower visibilities with areas of fog as well.

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

FORECAST CONFIDENCE: Low to Medium.

ALTERNATE SCENARIOS: Coverage and timing of showers and storms this
afternoon...and resultant MVFR/IFR restrictions may vary from
forecast. Isold LIFR possible tonight tonight in low stratus.

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    M    M    M    L    L    L    H    M    M
HTS CONSISTENCY  H    H    H    H    H    H    H    H    M    M    M    M
BKW CONSISTENCY  M    H    H    H    H    M    L    L    L    L    L    H
EKN CONSISTENCY  H    L    L    L    L    H    H    H    H    L    H    M
PKB CONSISTENCY  M    M    H    M    M    M    L    L    L    L    M    M
CKB CONSISTENCY  H    H    H    M    H    H    H    H    H    H    H    H

AFTER 18Z FRIDAY...
Areas of ifr possible in showers and thunderstorms through
Saturday, and in dense fog Sunday and Monday mornings.

&&

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

&&

$$
SYNOPSIS...MPK
NEAR TERM...MPK
SHORT TERM...JSH/30
LONG TERM...JSH/30
AVIATION...MPK


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