Area Forecast Discussion
Issued by NWS Charleston, WV

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FXUS61 KRLX 140620
AFDRLX

AREA FORECAST DISCUSSION
National Weather Service Charleston WV
220 AM EDT Wed Apr 14 2021

.SYNOPSIS...
Cold front later today and tonight. Unsettled weather at times
possible through the week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 215 AM Wednesday...

Next closed upper level low aloft will be taking a similar track
to the previous system, west to east through the Great Lakes
and then a southeastward turn towards the mid Atlantic coast.
Cyclogenesis at the surface produces a cold front that will
slowly drop into the Ohio Valley later today and into tonight.
Meanwhile, a baroclinic zone/nearly stationary boundary will
creep northward, residing just southeast of the CWA, and will
have a surface low tracking along it during the near term
period. All of this puts the CWA in a squeeze play. A band of
mid level frontogenesis develops later this morning, and will
see a line of showers as a result just north/west of the Ohio
River. This line of showers is already beginning to appear in
the ILN CWA. F-gen pushes southeastward this afternoon and this
evening into the mountains, while expanding in coverage. POPs
increase during this time, aided by brief periods of PVA in the
flow aloft. The trailing cold front will renew POPs in the
northeast mountains 06Z to 12Z Thursday. While instability
continues to be lacking, along with a good low level moisture
feed into the area of lift, the concentration and duration of
showers moving through has resulted in a modest increase in QPF
from the forecast 24 hours ago. Should be manageable in a
hydrologic sense, with a broader area in the half inch range for
the mountains.

Temperatures will be lower as a result of the precipitation
today. The northwestern zones in SE OH could have an afternoon
rebound once the showers depart and front passes with late
clearing.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY/...
As of 239 PM Tuesday...

A large upper low will drift southeastward across the Great Lakes
Wednesday night into Thursday and will eventually shift towards the
Northeast US by Friday. Vorticity maxima rotating around this
feature will provide enough lift to generate scattered precipitation
at times for a prolonged duration from Wednesday night into Friday
morning or possibly into Friday afternoon. Highest PoPs are expected
to occur in the mountains and generally northern parts of the
forecast area where the greatest lift and low level moisture is
expected to be in place, but southern portions of the forecast area
should be mainly dry during this period. The majority of this
precipitation should occur in the form of rain, but precipitation
could mix with or change to snow in the mountains Thursday night
into Friday morning as thermal profiles cool and the flow becomes
more favorable for upslope enhancement. Any snow accumulations
should be minor, but some light accumulations are at least a
possibility along some of the highest ridges. Otherwise,
temperatures will below normal both Thursday and Friday as the upper
low ushers in a cool air mass and any lingering precipitation in the
mountains should taper off by late afternoon or evening on
Friday. In addition, there will also be some potential for frost
later this week with the greatest concern expected to be on
Thursday night with overnight lows dipping down into the mid to
upper 30s across the lowlands.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
As of 239 PM Tuesday...

As the aforementioned upper low continues to depart to the east
of the area on Friday night, some brief ridging may develop for
at least the first part of Saturday to bring a dry start to the
long term period. However, the GFS shows precipitation returning
back to the area by late Saturday as an upper level trough
approaches the region, but the ECMWF is weaker with this feature
and keeps most of the moisture to the south of the area. Thus,
will only go with low PoPs in the forecast for now on Saturday
but it appears that precipitation chances will increase a bit
further by Sunday as models show a mainly zonal and progressive flow
aloft developing with a series of shortwave disturbances moving
through. This pattern should keep conditions unsettled at times
through early next week with temperatures gradually warming
each day and perhaps returning to normal values by the end of
the period.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
As of 120 AM Wednesday...

No fog tonight due to increasing cloud cover overall from a mid
level deck. Area getting a squeeze play from a frontal boundary
to the southeast and low pressure riding along it, and a
developing cold front to the northwest through central Ohio.
Expecting showers to develop and sink southeastward through the
Ohio Valley and into the central Appalachians.

Ceilings will lower as this occurs, with low end MVFR expected
for the lowland terminals, and IFR possible in the mountains
after 18Z. Showers could bring down visibilities intermittently,
but figure this should occur often enough to include in
prevailing conditions going forward.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z THURSDAY...

FORECAST CONFIDENCE: High.

ALTERNATE SCENARIOS: Timing of showers and lowering ceilings may
vary slightly from forecast.

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.

DATE                              WED 04/14/21
UTC 1HRLY       06   07   08   09   10   11   12   13   14   15   16   17
EDT 1HRLY       02   03   04   05   06   07   08   09   10   11   12   13
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    M    H    H
BKW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
EKN CONSISTENCY  H    H    H    H    H    H    H    H    M    H    M    M
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    M
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    M    H

AFTER 06Z THURSDAY...
No widespread IFR conditions expected at this time.

&&

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

&&

$$
SYNOPSIS...26/CG
NEAR TERM...26
SHORT TERM...RG
LONG TERM...RG
AVIATION...26


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