-- Discussion containing changed information from previous version are highlighted. --
724
FXUS61 KRLX 221027
AFDRLX

AREA FORECAST DISCUSSION
National Weather Service Charleston WV
627 AM EDT Sun Sep 22 2024

.SYNOPSIS...
Dry and hot today. Unsettled weather returns late tonight into
the new work week, bringing beneficial rainfall back into the
area.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
As of 625 AM Sunday...

Little to no changes were needed to the forecast this morning.
Dense river valley fog continues to flourish across the forecast
area this morning, with visibilities of half a mile or less
quite common along our most traveled roadways. In coordination
with surrounding offices, a Dense Fog Advisory will remain in
effect until 9 AM this morning to highlight the concern for
hazardous travel conditions across parts of southeast Ohio and
north-central West Virginia, where rain was observed yesterday
afternoon and evening.

As of 215 AM Sunday...

Satellite imagery early this morning reveals river valley fog
growing in coverage and intensity across northeast West Virginia
and along the southern Ohio River Valley. These two areas were
noted to have received measurable rainfall on Saturday from a
cold front and will likely festering through the predawn hours
into daybreak this morning. A Dense Fog Advisory could be
warranted later on this morning if half mile to quarter mile
visibilities continue down into our more populated areas.

The frontal boundary planted directly over the forecast area
early this morning is progged to shift slightly northward today
as a warm front. This will place the Central Appalachians in the
warm sector of an encroaching disturbance slated to arrive late
tonight into early Monday morning. In the meantime, afternoon
temperatures in the Tri-State area and into the central lowlands
will once again topple over the 90 degree mark.

Minimum relative humidity values will bottom out into the 20 to
30 percent range during peak heating hours this afternoon in
the lower elevations and down into the 30 to 40 percent range
along the mountains and southern coalfields. This will be the
last day through the foreseeable future for these low RH values
as low level moisture becomes present over the next several
days. We should lack the wind component today when it comes to
fire weather concerns.

A low pressure system tracking through the Ohio Valley today
will invade the forecast area by dusk this evening. Clouds will
first arrive this evening, followed by a line of broken showers
and thunderstorms late tonight into the overnight hours. This
marks the revival of unsettled weather for the start of the new
work week and brings beneficial rainfall to the area. Within
this portion of the forecast, QPF totals range from a few
hundredths to a tenth of an inch across southeast Ohio and
eastern Kentucky, where POPs will first arrive overnight.
-- End Changed Discussion --

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
As of 305 AM Sunday...

A moist airmass is forecast to be in place Monday through Tuesday as
the region sits in the open warm sector of a slow moving surface low
transiting the Mid-West. Diffluent flow aloft should allow for both
nocturnal elevated convection as well as diurnally enhanced surface
based storms Monday. Initially, deep layer shear will be on the
weaker so not expecting too much in the way of storm organization
Monday. The main threat with any activity will be locally heavy
downpours. While any rain would be largely beneficial, could see
some localized drainage issues over built up areas should one of
these downpours dwell too long.

Deep layer flow increases on Tuesday in response to the parent upper
trough approaching the region. Contingent on diurnal destabilization
could see a severe threat emerge for Tuesday afternoon with locally
damaging winds, and perhaps a low end tornado threat as the primary
hazards, most likely focused from the Metro Valley down the Tug
Fork, although confidence is low this far out.

Cold frontal passage is then expected Wednesday. At present this
looks to occur relatively early in the day and not yield as much of
a chance to destabilize diurnally.

Ensemble guidance is reasonably confident in the combination of this
activity to produce widespread beneficial rain, which should help
take the edge off very dry unsheltered fine fuels, even if it won`t
put much of a dent in our rainfall deficit. Interquartile 72hr
amounts ending Thursday morning range from around half an inch to
near 2 inches, highest in the northeast with our current
deterministic forecast generally falling in this range.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
As of 305 AM Sunday...

Confidence is low for the the long term period with a wide range in
model solutions. Generally most confident in amplification of the
northern stream that would help to shunt any potential tropical
moisture from development in the Gulf of Mexico east of us keeping
our region mainly dry, but a non-trivial number of ensemble members
are subdued enough with this feature to allow tropical moisture this
far west. This is reflected in a significant interquartile spread in
QPF values for the latter half of the week. For the deterministic
forecast will continue to defer to central guidance advertising
some lower end PoPs each day into next weekend for now.

&&

.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
As of 625 AM Sunday...

Dense river valley fog is quite apparent on nighttime satellite
imagery this morning, having now made it into all but two of our
TAF sites. The last site to see fog attempt to trickle in this
morning will be CRW. Should see conditions improve shortly after
13Z/14Z this morning as the erosion of low vsbys/ceilings
branches out into a mostly quiet day. A disturbance stretching
in from the west will begin to yield lowered ceilings late
tonight into Monday morning, with rain spreading in from west to
east. Out ahead of the precipitation shield, fog will once again
attempt to form in our river valleys. Western terminals may have
a more difficult time with fog production with the mid to upper
level cloud deck moving in from the Ohio Valley. Will hint at
most sites seeing fog tonight, but modifications are certainly
not out of the question with future TAF issuances.

Winds will be light and variable through the this evening,
becoming more southerly overnight into the end of the valid TAF
period.

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

FORECAST CONFIDENCE: Low to Medium this morning, then becoming
High after the erosion of fog.

ALTERNATE SCENARIOS: Improving conditions may vary from the
forecast after daybreak as fog scatters and lifts.

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               SUN 09/22/24
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  M    L    L    H    M    H    H    H    H    H    H    H
BKW CONSISTENCY  L    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  L    L    L    M    L    H    H    H    H    H    H    H
CKB CONSISTENCY  H    H    H    H    L    L    H    H    H    H    H    H

AFTER 12Z MONDAY...
Brief IFR possible in any heavier showers and thunderstorms
Monday afternoon through early Wednesday morning.
-- End Changed Discussion --

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...Dense Fog Advisory until 10 AM EDT this morning for WVZ009>011-
     017>020-028>032-039-040-521>526.
OH...Dense Fog Advisory until 10 AM EDT this morning for OHZ076.
KY...None.
VA...None.

&&

$$

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