203
FXUS61 KRNK 241739
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
139 PM EDT Tue Sep 24 2024

.SYNOPSIS...
A slow-moving cold front will meander along the Ohio River
Valley over the next several days, triggering rounds of showers
and thunderstorm activity that will persist through much of the
workweek. PTC 9 lifting northward from the Gulf of Mexico toward
the end of the work week may bring more widespread rainfall to
the region.

No major changes were made to the forecast grids this morning as
temperatures have remained on track across the region. Clearing
has started west of the Appalachians this morning, which will
lead to increased destabilization as the morning and afternoon
progresses today. Expect clearing to continue to progress east
to just east of the I-81 corridor through the afternoon, which
will set up the potential for severe storms through the evening
and early overnight hours. Localized flash flooding will also be
a potential threat across the area today as training storms may
develop through the late evening.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 200 AM EDT Tuesday...

Key Messages:

1) Thunderstorms this afternoon, a few may be strong to severe.

2) Heavy rain from training thunderstorms could result in areas
of localized flooding.

A look at the current surface analysis this morning indicates a
warm front located across Central Virginia extending southeast
into eastern North Carolina. Another boundary, currently
stationary is situated across Kentucky and West Virginia. This
has resulted in a highly moist boundary layer across much of
Virginia and North Carolina. Weak isentropic lift associated
with the warm front across Virginia has resulted in ongoing
shower activity. CAM guidance suggests an uptick in this
activity as the morning progresses and the front begins to
gradually sag southwest through daybreak. Some uncertainty
exist on how much this front can progress southwest by this
afternoon.

Upper divergence aloft associated with an approaching upper
trough will pass over the region this afternoon and evening.
Best forcing will be just to the west, however depending on the
location of the backdoor front and amount of heating that can
occur today will play a role in the intensity and coverage of
thunderstorms. Should we see more sun than clouds today, storms
will be capable of strong damaging winds and possibly a few
instance of hail. A very anomalously moist airmass remains in
place as well, thus any storm will be produce very efficient
rainfall rates and could pose a threat for localized flooding.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
As of 200 AM EDT Tuesday...

Key Messages:

 - Outer rain bands from Tropical Cyclone Nine could enter the area
as early as Thursday night.

 - Seasonal temperatures and high humidity through the period.

On Wednesday, an upper level low will wobble over the Ozarks while
an upper level ridge sits off the southeast coast. The forecast area
will be under the influence of the upper ridge into the day
Thursday. With a southeasterly low level flow into the region,
showers and a few thunderstorms are possible each afternoon,
starting along the Blue Ridge.

Late Thursday afternoon, Tropical Cyclone Nine is expected to move
inland around the Tallahassee Florida area then tracks northward
towards the southern Appalachian mountains (GA/TN/NC border). Outer
rain bands of TC Nine could move over the area as early as Thursday
night, continuing into Friday. However, the cone of uncertainty
widens as this tropical system moves inland on days 3 and 4.

Near normal temperatures are expected Wednesday and Thursday.
Dewpoints will run from the mid 60s to lower 70s through the period.

&&

.LONG TERM /SATURDAY THROUGH MONDAY/...
As of 230 AM EDT Tuesday...

Key Messages:

 - Confidence is increasing that Tropical Cyclone Nine will affect
the area Friday and Saturday, though exact impacts remain uncertain.

 - High pressure wedge south across the area Sunday and Monday.


Rain bands from Tropical Cyclone Nine are expected to move over the
forecast area through the day Friday. These rain bands may also
interact with a backdoor cold front Friday night into Saturday
night. With PWATs running on the order of +1.50 inches, periods of
moderate to heavy rain are possible going into the weekend. Models
have the front wedging south on Sunday.

The upper level low that was over the Ozarks should open into a
trough on Monday and track over the Mid Atlantic states Monday and
Tuesday. Dry high pressure returns to the area follow the passing of
this trough.

With rain expected Friday and Saturday, temperatures will run
slightly cooler than normal. The backdoor front will bring cooler
air into the area with temperatures around 10F cooler than normal.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
As of 130 PM EDT Monday...

Clearing across southwest Virginia and southeastern West
Virginia has lead to scattered shower and thunderstorm
development across these regions over the last hour or so. This
will lead to VCTS conditions at KBLF, KLWB, KBCB, and KROA for
the next several hours and into the evening. As these showers
and thunderstorms pass near or over terminals, expect brief MVFR
to LIFR conditions. KDAN and KLYH look to remain under dense
cloud cover through the entire TAF period; however, TSRA
conditions look to impact both terminals through the overnight
hours. MVFR to LIFR conditions look to return to all terminals
beyond 0900 UTC Wednesday, and linger through 12-15 UTC on
Wednesday before conditions start to improve to MVFR to VFR
levels as visibilities increase, and CIGs lift.

EXTENDED AVIATION OUTLOOK...

MVFR/IFR stratus and fog are expected to occur in rounds through
at least the middle of the week, and increasingly likely to
persist through the end of the workweek. Rounds of showers and
thunderstorms will also continue to pass across the lower Mid-
Atlantic.

Low pressure lifting northward from the Gulf of Mexico toward
the end of the week may bring more widespread rainfall and sub-
VFR conditions to the region.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.

&&

$$

SYNOPSIS...BMG/EB
NEAR TERM...BMG
SHORT TERM...RCS
LONG TERM...RCS
AVIATION...BMG/EB