Area Forecast Discussion
Issued by NWS Charleston, WV

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FXUS61 KRLX 222021
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
321 PM EST Wed Feb 22 2017

.SYNOPSIS...
Unseasonably warm weather returns again Thursday and Friday.
A strong cold front crosses first thing Saturday morning,
followed by cooler weather for the weekend.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 3 PM Wednesday...

Wave was quickly exiting the area this afternoon, taking the
last of the rain with it. Stratocu is likely to linger tonight,
limiting fog formation but still do expect some.

Thursday will bring a continuation of south to southwest flow
with low level moisture remaining in place. Heating is forecast
to increase CAPE to 500-700 J/KG. This, along with weak shear,
could give rise ton a few thunderstorms as a weak upper level
short wave trough crosses in west to southwest flow, but nothing
organized is expected.

Temperatures close to a blend MET/MAV and bias corrected
consensus.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
As of 310 PM Wednesday...

Models continue to slow down frontal passage. Latest ECMWF and
NAM guidance having the front near the Ohio River by 12Z
Saturday and the GFS continues to bisect WV with the front by
that time. I have held off on PoP until a few hours later than
previous forecast, with Categorical PoP in the Ohio Valley
between 6Z - 7Z, but this may still be a bit early.

The main concern with this front will be the possibility of
isolated damaging wind gusts in convection. Overall,
instability is rather weak, with NAM and GFS indicating anywhere
from 300 to 600 J/Kg of CAPE with the highest values in the
Ohio Valley. However, wind shear values are very impressive with
65 to 70 knots of 0 - 6km bulk shear. Also, upper trough turns
slightly negative as it crosses the region and 700mb to 500mb
lapse rates increase to 8C/km. It is possible that we could see
a weakening QLCS entering the Ohio Valley by early Saturday
morning. With the impressive wind shear and modest instability
in the Ohio Valley, there is a chance that convection could
bring some strong wind gusts down to the surface. With the
overnight timing of the front though, the threat for damaging
winds will be low, but isolated damage and power outages will be
possible in the Ohio Valley and that threat will decrease
heading east across West Virginia.

The cold front clears the area on Saturday and strong cold air
advection pushes in behind it. There may be enough lingering
moisture with the upslope NW flow behind the front that the
mountains squeeze out a few snow showers.


&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 315 PM Wednesday...

Start off the long term with high pressure over the region, but
this will be short lived as zonal pattern is set up across the
U.S. Guidance is in a little better agreement with southern
stream wave pushing across the area on Monday. This will be the
first of what looks like several systems moving through the
progressive pattern next week.

&&

.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
As of 115 PM Wednesday...

Rain will slowly move out of southern Wv this afternoon,
followed by slowly improving conditions. IFR conditions at HTS
and CRW should improve by around 21Z or so. There is a chance
IFR conditions develop at BKW around 21-23Z. Farther north, MVFR
stratocu over the middle Ohio valley may get to CKB for a time
this evening.

Stratocu will be mainly above 3 kft tonight, but MVFR fog may
form. Showers may bring MVFR conditions into the middle Ohio
Valley by midday Thursday. Otherwise VFR conditions are
expected through 18Z Thursday.

Surface flow will be light south beneath light to moderate
southwest aloft.

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

FORECAST CONFIDENCE: Medium.

ALTERNATE SCENARIOS: IFR may vary this afternoon at HTS, CRW
and BKW. Fog formation tonight is in question.

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
EST 1HRLY       13   14   15   16   17   18   19   20   21   22   23   00
CRW CONSISTENCY  M    L    M    M    M    H    H    H    H    H    H    L
HTS CONSISTENCY  H    H    M    M    M    H    H    H    H    H    M    L
BKW CONSISTENCY  H    H    M    M    M    M    H    H    H    H    H    L
EKN CONSISTENCY  H    H    H    H    H    M    H    L    M    M    M    M
PKB CONSISTENCY  H    H    H    H    H    H    H    M    M    H    L    L
CKB CONSISTENCY  H    H    H    H    H    H    M    M    M    H    M    L

AFTER 18Z THURSDAY...
No widespread IFR conditions are expected at this time.

&&

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

&&

$$
SYNOPSIS...TRM/MPK
NEAR TERM...TRM
SHORT TERM...MPK
LONG TERM...MPK
AVIATION...TRM



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