Area Forecast Discussion
Issued by NWS Charleston, WV

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FXUS61 KRLX 031402
AFDRLX

AREA FORECAST DISCUSSION
National Weather Service Charleston WV
1002 AM EDT Wed Jun 3 2020

.SYNOPSIS...
Strong to severe thunderstorms possible along a slow moving cold
front this evening. Storm chances linger through Saturday. Cold
front brings dry weather Sunday through Tuesday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 1000 AM Wednesday

Current forecast is on track.

As of 600 AM Wednesday...

Made some updates to hourly temps to reflect warm air advection
wiping out weak surface based inversions in a few spots. Also
tweaked cloud cover to represent convective debris from decaying
complex dropping south from Lake Erie.

As of 200 AM Wednesday...

Strong low level warm air advection associated with 35-40KT westerly
low level jet is generating some low level cloudiness up against the
higher terrain this morning, but otherwise mainly clear skies
prevail. Convective complex dropping into the Lower Great Lakes this
morning will likely contribute some cirrus to the region by
daybreak, but any lingering rain showers look to stay well north of
the area.

High temperatures approach 90 degrees across the Lowlands with
surface dewpoints in the upper 50s south, mid 60 central and
upper 60s to lower 70s north. This should setup a decent
instability gradient from the Metro Valley/I-79 north this
afternoon.

An eroding warm layer between H850-H700 could potentially allow a
few towers to go up across SE OH/NW WV around peak heating this
afternoon. Meso models do depict a subsidence inversion based around
H850 progressively mixing out, but in the absence of any other
forcing still may not be able to get through before heating wanes.
CAMs seem pretty insistent on this solution, but will include at
least some isolated TS across this area this afternoon. Bulk
shear is a little on the light side, around 30KTs, but MLCAPE
around 2500J/kg would yield a mainly large hail/damaging wind
threat with anything that can develop.

A majority of the convection is expected to fire along a slow moving
cold frontal boundary expected to be oriented roughly west-east
along the I-70 corridor this afternoon, then drift south into our
northern counties during the evening hours. While convection will be
trending down by the time this occurs, could still see few stronger
storms capable of producing some damaging wind gusts and perhaps
some marginally severe hail with any storm scale interaction into
the early overnight. Still some question as to how far south showers
and non-severe storms will be able to make it via outflow
propagation moving into an increasingly hostile environment and
don`t think we will have a real clear picture of this until we see
how storms evolve through the evening hours.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY/...
As of 240 AM Wednesday...

Expecting lingering outflow boundaries, weak waves aloft, and
surface pressure troughs through the period in moderately
unstable air to keep the chances for convection going through
the entire short term. This will be the case until the next
airmass changing cold front comes through, at the break point
for the long term period Saturday night. Despite the lessening
coverage after sunset each day, the elevated instability will
keep the potential for storms going during the overnight hours.
For the Thursday time frame, there will be some mid level dry
air that will need to be overcome in convection, and could
actually see increased coverage going into the Thursday
evening/night period as that dry air is eliminated. Column will
be better saturated Friday, but by Friday evening, a dry air
intrusion aloft will arrive, and may need to watch this for an
increased wind threat. Speed shear in the low/mid levels will be
somewhat hard to come by, mainly 15-20kts in the effective
layer and SPC risks are capped at marginal for the region.
Rainfall amounts will need to be watched, with convection
expected over an extended period of time and multiple rounds
possibly hitting the same area in these slow moving warm season
rainers.

&&

.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
As of 240 AM Wednesday...

Cold front comes through and stabilizes the atmosphere, leading
to a dry extended period. Temperatures moderate some, but with
an upper level ridge building off to the west and sliding east,
a warm will occur heading into the middle of next week. Beyond
the extended, may need to watch tropical remnants and its motion
in relation to the aforementioned ridge.

&&

.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
As of 600 AM Wednesday...

Clouds from morning convection over Lake Erie will stream
through the region for the next few hours before clearing out by
late morning.

Will see increasing convective debris from storms forming north
of the area along I-70 begin streaming back into the area by
this afternoon. These storms will gradually shift south into our
area during the late evening/overnight hours mainly affecting
PKB, CKB and EKN before dissipating.

IFR conditions will be possible in any heavier downpours and
along the slowly southerly sagging frontal boundary Thursday
morning.

Winds this afternoon will be breezy from the west-southwest
again today, 9-11KTs with gusts up to around 20-25, tapering off
this evening.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z THURSDAY...

FORECAST CONFIDENCE: High.

ALTERNATE SCENARIOS: Isolated storms have a low probability of
developing well ahead of the main line of storms, potentially
impacting PKB by 20-21Z.


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       12   13   14   15   16   17   18   19   20   21   22   23
EDT 1HRLY       08   09   10   11   12   13   14   15   16   17   18   19
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    H    H    H    H    H    H
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 12Z THURSDAY...
IFR possible in showers and thunderstorms Thursday.

&&

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

&&

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



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