Area Forecast Discussion
Issued by NWS Charleston, WV

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FXUS61 KRLX 171743
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
143 PM EDT Thu Aug 17 2017

.SYNOPSIS...
Hot and humid today. Cold front tonight into Friday. Generally
drier afterwards until Tuesday. Another cold front by mid week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 1220 PM Thursday...Updated PoP to reflect on current
radar and trends, as isolated showers are popping up across the
east and more numerous showers now developing across the Ohio
Valley.


As of 930 AM Thursday...Ran an update to decrease cloud cover
this morning and lowered PoP until later this afternoon. Current
guidance is showing a weak prefrontal trough that will push
through early this afternoon into the early evening hours.
Should at least see scattered showers and thunderstorms pop up
with this feature and with PWATs close to 2", high freezing
level, and long skinny CAPE profiles these showers and storms
will be efficient rainfall producers. Later tonight the cold
front will enter the Ohio Valley between 8 and 10 PM and push
across the region. The best shear and dynamics with this front
is still going to be off to our north, but if the front can
arrive early enough and can tap into the better instability,
then there is some concern that some storms may contain strong
gusty winds across our far Northwestern Zones.

As of 645 AM Thursday...

Clouds will be on the increase early this morning as a surface
and upper level low move through the Northern Plains. The first
impulse associated with the upper air feature should kick off
showers and thunderstorms across the Tri-state mid morning,
with activity drifting NE through the afternoon. Decent
instability across the area with the hot and humid air in place
-- MLCape should be in the 1000-1500J/kg range. The CAPE
profile is rather skinny and shear of 20-30kts is fairly
marginal for strong to severe storms. However, with precipitable
water values topping 2 inches, heavy rain is likely in mature
convection. Flash flood guidance is generally 1.5-2.5 inches
across the forecast area. The most likely area of heavy rain
today -- across the Ohio River Valley and western lowlands of WV
-- corresponds to the higher FFG so not planning a flash flood
watch. Still...cannot rule out isolated issues with repetitive
storms.

Tonight, we should have a line of showers and thunderstorms move
from west to east ahead of a cold front. Instability drops off
quickly 00Z Friday, but precipitable water remains on the high
side... so again strong to severe storms not expected but heavy
rainfall is likely.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
As of 310 AM Thursday...

What remains of a cold front crosses the CWA Friday for scattered
showers.

A weak upper level wave brushes the northern CWA over the
weekend though high pressure will likely keep the rest of the
area rain free and warm.

High pressure continues Sunday for dry weather area wide.

&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
As of 310 AM Thursday...

High pressure continues Monday for dry weather area wide. Moisture
will increase Tuesday and Wednesday ahead of the next
approaching cold front. The cold front crosses Wednesday into
Thursday.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
As of 1245 AM Thursday...

Scattered showers and thunderstorms will continue this
afternoon. There may be brief lull before another line of
showers and storms pushing through late this evening through
tonight with a passing cold front. Brief IFR will be possible
just about anywhere if a shower or storm moves overhead. For now
have only included IFR at CRW and PKB based on current storms on
Radar moving towards the airfields. Behind the front there may
be some low stratus early Friday morning. Conditions should
improve to VFR again tomorrow.

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

FORECAST CONFIDENCE: Medium.

ALTERNATE SCENARIOS: Will likely need amendments for IFR in
storms today through 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  H    H    H    H    H    H    H    H    H    H    H    M
HTS CONSISTENCY  M    H    H    H    H    H    H    H    H    H    H    L
BKW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    M
EKN CONSISTENCY  H    H    H    H    M    H    H    H    H    H    H    L
PKB CONSISTENCY  H    H    H    H    H    H    H    H    M    M    M    L
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    M

AFTER 18Z FRIDAY...
Dense river valley fog possible each morning.

&&

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

&&

$$
SYNOPSIS...JW/MZ
NEAR TERM...MZ/MPK
SHORT TERM...JW
LONG TERM...JW
AVIATION...MPK



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