452
FXUS61 KRLX 121742
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
142 PM EDT Sat Sep 12 2026

.WHAT HAS CHANGED...
Aside some minor tweaks, the forecast involving the heavy rain
potential for this afternoon and tonight remains on track. The Flood
Watch remains unchanged. The forecast for Sunday and beyond also
remains on track.

18Z aviation forecast has been issued.

&&

.KEY MESSAGES...
1) A Flood Watch remains in effect for most of the forecast area
until 1 AM EDT tonight.

2) Additional chances for showers and thunderstorms remain forecast
for Sunday as a cold front moves in from the northwest.

&&

.DISCUSSION...
KEY MESSAGE 1...

15Z upper air analysis depicts a progressive troughing pattern
across the eastern half of North America, featuring a longwave
trough pivoting into Ontario and a shortwave trough ejecting into
the TN River Valley. The latter feature is beginning to become
absorbed into the longer-wave trough to the north, with a wide
baroclinic leaf evident on water-vapor imagery that was advecting
over the OH River Valley and into the CWA. Observations outside of
WFO RLX confirm that the leading band of moist, isentropic ascent in
the mid-levels has arrived via the presence of altostratus and
ACCAS; and gradual destabilization of the airmass will continue to
occur given the presence of the high-level cirrus deck. Meanwhile,
elevated clusters of showers and thunderstorms were ongoing across
southeastern OH, and may clip the northwestern counties. The 12Z
objectively analyzed UA charts indicated a sharply cyclonic
component to the southern-stream trough at 250 mb, with a belt of
southwesterly flow between 30-40 kt within the 300-200 mb layer
before weakening near 500 mb where broader concavity to the trough
exists. High humidity was also observed within the high-level theta
surfaces, amidst a very tall and skinny EML (i.e., RAOBs from nearby
WFOs observed the top of the EML as high as 175 mb) in congruence
with the vigorous, moist ascent. The shortwave trough is also now
completely open compared to yesterday, with the remnant vorticity
lobe rotating over central TN. This feature will eject northeastward
over the CWA throughout the next 12 hours before quickly exiting to
the northeast as its absorption into the aforementioned longwave
trough over east-central Canada is completed.

At the surface, the warm front is now crossing north of the I-64
corridor, and it will continue to increase in forward speed as it
advects northeastward across the CWA. The closest cyclone is either
on the lee of the Appalachian Mountains or in the Upper Midwest,
thereby leaving the CWA within a broad, open moist sector as the
warm front lifts northeastward, with dewpoints hovering in the lower
70s area-wide. Strong heating is also underway, although the fairly
opaque cirrus shield has prevented full insolation from occurring,
and temperatures are expected to peak in the middle 80s. Low-level
convergence of the higher theta-e air may spawn a surface low
beneath the intensifying belt of divergence aloft and serve as a
foci for organized bands of torrential rainfall. Mean wind vectors
throughout the cloud-bearing layer are also oriented out of the
southwest at about 20 kt per the 12Z RAOBs from WFOs ILN and RNK,
which is parallel to the steering flow, and will pose a risk for
cellular training.

Anomalously high PWAT values approaching 2.00", combined with MLCAPE
values between 1,500-2,000 J/kg and cloud-layer shear magnitudes of
25-30 kt, in conjunction with the parallel convective movement
relative to the mean wind, has resulted in high confidence for
multiple episodes of flash flooding this afternoon and tonight
across the CWA. Instantaneous rain rates may exceed 2"/hr with the
strongest storms. The Flood Watch remains in effect for all counties
except Pocahontas County until 1 AM EDT tonight. In addition to the
flash flooding risk, locally strong-to-severe-caliber wind gusts
cannot be ruled out with the best-organized storms, but the threat
this afternoon and tonight is geared towards flash flooding. Storms
will wane from west-to-east late tonight, followed by widespread fog
and low-level stratus during the predawn hours Sunday.

KEY MESSAGE 2...

The base of the longwave trough over east-central Canada will dig
into the Great Lakes region Sunday, with the respective synoptic
cold front currently located in the Upper Midwest expected to move
into the CWA late Sunday afternoon. Prior to the arrival of the
front, thick, low-level stratus and fog will be intact area-wide
during the morning hours. Mixing of the airmass will be gradual,
with most of the fog and/or low stratus dissipating by the latter
half of the morning. Highs will breach into the middle 80s once
again Sunday, with the airmass remaining capped near 700 mb and
suppress any bubbling of boundary-layer cu. The most substantial
large-scale forcing for ascent will be displaced well to the north
of the CWA; however, frontogenetical forcing along the weakening
cold front may result in broken line of showers and storms late
Sunday evening into early Monday morning. Diabatic stabilization
will result in a gradual cessation of lightning, but brief downpours
may still accompany showers overnight Sunday into Monday, with a
much lower risk for flash flooding, if any. Intrusion of a 1026 mb
surface anticyclone will result in a milder day Monday before
temperatures heat up mid-week as a subtropical ridge rotates
eastward across the Deep South. Renewed rain chances are forecast
heading into the middle of next week.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
Numerous SHRA/TSRA are expected to form this afternoon and last into
tonight, affecting all terminals. IFR or lower will accompany TSTMs,
with surface wind gusts >30 kt possible. Coverage of TSTMs will wane
from west-to-east after dark; however, IFR/LIFR CIGs and VSBYs are
forecast to evolve late tonight and through the predawn hours
Sunday. BLO MINS may occur, with a return to VFR at all terminals
late Sunday morning. Otherwise, winds this afternoon will prevail
from the south-southwest at 7-10 kt, with an overcast MVFR/VFR deck
outside of any SHRA/TSRA.

FORECAST CONFIDENCE: High.

ALTERNATE SCENARIOS: The magnitude of CIG/VSBY restrictions with
TSTMs and the timing of when TSTMs end tonight may vary from what
is 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.

UTC 1HRLY       18   19   20   21   22   23   00   01   02   03   04   05
EDT 1HRLY       14   15   16   17   18   19   20   21   22   23   00   01
CRW CONSISTENCY  H    H    H    H    H    H    H    H    H    M    M    L
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    H    M    M
BKW CONSISTENCY  H    H    H    H    H    H    H    H    M    H    H    L
EKN CONSISTENCY  H    H    H    H    H    H    H    H    H    M    M    L
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    L
CKB CONSISTENCY  H    H    H    H    H    H    M    H    H    H    M    M

AFTER 18Z SUNDAY...
VFR, with light, westerly winds are forecast Sunday afternoon. A
cold front will approach from the northwest late Sunday afternoon,
with additional -SHRA/-TSRA possible.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...Flood Watch until 1 AM EDT Sunday for WVZ005>011-013>020-
     024>034-039-040-515>522-525-526.
OH...Flood Watch until 1 AM EDT Sunday for OHZ066-067-075-076-
     083>087.
KY...Flood Watch until 1 AM EDT Sunday for KYZ101>103-105.
VA...None.

&&

$$

DISCUSSION...Sincavage
AVIATION...Sincavage