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238
FXUS61 KRLX 201021
AFDRLX

AREA FORECAST DISCUSSION
National Weather Service Charleston WV
621 AM EDT Fri Sep 20 2024

.SYNOPSIS...
A few showers and storms may develop along the mountains this
afternoon, but otherwise mostly dry and warm under high
pressure. A weak system passes through over the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
As of 620 AM Friday...

Freshened up temperatures and dew points this morning where a
few stations were observing slightly higher readings than
anticipated. This is most likely attributed to pockets of low
hanging clouds that hovered overnight and mitigated radiational
cooling from occurring. Otherwise, forecast remains on track
with river valley fog now spilling down into the central
lowlands this morning. This will gradually erode as the sun
continues to rise.

As of 235 AM Friday...

Surface high pressure slides slightly eastward today, but
retaining enough influence over the forecast area that will
yield mostly dry weather through the period. Early morning
microphysics satellite imagery shows river valley fog underway
along the higher terrain and is expected to spread further down
into the lowlands before dawn.

Any fog development this morning will gradually erode after
sunrise and give way to afternoon cumulus, especially along the
mountains. Additional growth along the higher terrain may foster
isolated showers and storms during peak heating hours.

Otherwise, above seasonable temperatures prevail across the
Central Appalachians today, with a few areas within the Tri-
State area and along the I-64 corridor reaching the low 90s. A
slight dip in dew points during the afternoon will bring
relative humidity values down into the 30 percent range across
the lower elevations. Light surface flow will be present
throughout the day, but dry fuels may attempt to stimulate fire
weather concerns in areas that have not received measurable
precipitation in quite some time.

A cold front marching into the Ohio Valley late tonight will
stem from a weakening disturbance north of the United States
border. Latest model runs depict a delay in showers entering the
forecast area within the valid forecast period, so opted to
trend back POPs overnight. Otherwise, another decent signal for
mountain fog seems plausible for late tonight into early
Saturday morning.
-- End Changed Discussion --

&&

.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
As of 0334 AM Friday...

Upper level shortwave passes through the region on Saturday with a
Marginal Risk for severe storms over the mountains/far eastern
portions of the CWA. The CAMs are rather lackluster at this time,
but there is certainly a window of opportunity for some storms to
become strong to locally severe before exiting the area. Main
threats will be isolated strong winds and marginally severe hail.
While the main threat is east of the lowlands, its worth mentioning
there could be some isolated showers and a rumble of thunder or two
across the lowlands Saturday morning, however confidence is low.

Daytime highs will be quite warm in the middle and upper 80s to near
90 degrees for the lowlands with 70s in the mountains. FG is
expected Saturday night into Sunday morning for much of the mountain
valleys and could be more widespread into the lowland valleys than
past days.

With the shortwave trough through the region by Sunday, some drier
air will work its way into the area. Min RHs will likely dip into
the 30s for much of the lowlands and 40s for mountains. With mostly
sunny skies, seasonably hot temps in the upper 80s to around 90
degrees, elevated fire weather conditions is possible during the
afternoon.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 334 AM Friday...

A warm front will pass through the area Sunday into Monday as the
aforementioned low pressure system, which developed over the Rockies
Saturday, tracks eastward. Models are generally dry over our area
for Sunday, with rain chances returning Monday as a stronger mid-
level wave of energy from the aforementioned low approaches
from the northwest. Rain chances will continue into Tuesday as
a cold front approaches from the west. Models begin to diverge
from Wednesday onward, but we opted to forecast near central
guidance, which suggests at least some chances of rain
Wednesday and Thursday next week. After starting the week
unseasonably hot across the lowlands, temperatures may trend a
few degrees below average for mid-to-late week with a potential
upper- level low somewhere over the East. Plenty of uncertainty
in the long-term forecast, so our confidence remains low.

&&

.AVIATION /10Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
As of 620 AM Friday...

River valley fog that spent most of the overnight only along the
mountain range has now spilled down into the central lowlands at
the time of writing. IFR/LIFR conditions continue to bounce
around at our TAF sites this morning, with the exception of BKW.
Fog will gradually erode over the next few hours and return all
sites to VFR.

For today, high pressure will yield mostly quiet weather around
Central Appalachia, but a few afternoon cumulus clouds may grow
into a shower and/or brief thunderstorm this afternoon along the
mountains. There is another decent signal for fog late tonight
into Saturday morning within the mountain valleys. Winds remain
light and variable today.

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

FORECAST CONFIDENCE: Low this morning within fog; becoming High
after daybreak.

ALTERNATE SCENARIOS: Timing of improving vsbys may vary this
morning during fog erosion.

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               FRI 09/20/24
UTC 1HRLY       09   10   11   12   13   14   15   16   17   18   19   20
EDT 1HRLY       05   06   07   08   09   10   11   12   13   14   15   16
CRW CONSISTENCY  M    M    M    M    M    H    H    H    H    H    H    H
HTS CONSISTENCY  L    L    L    L    H    H    H    H    H    H    H    H
BKW CONSISTENCY  H    L    L    H    H    H    H    H    H    H    H    H
EKN CONSISTENCY  M    M    M    M    L    L    H    H    H    H    H    H
PKB CONSISTENCY  M    M    M    M    M    H    H    H    H    H    H    H
CKB CONSISTENCY  M    L    L    H    H    H    H    H    H    H    H    H

AFTER 12Z SATURDAY...
IFR conditions possible Saturday and Sunday morning along the
higher terrain from river valley fog.
-- End Changed Discussion --

&&

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

&&

$$

SYNOPSIS...JRM/MEK
NEAR TERM...MEK
SHORT TERM...JRM
LONG TERM...JRM
AVIATION...MEK