345
FXUS61 KRNK 051853
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
253 PM EDT Wed Jun 5 2024

.SYNOPSIS...
A warm and moist airmass will remain over the area through
Thursday promoting showers and thunderstorms. A cold front will
move through the region Thursday night introducing drier and
cooler weather to start the weekend.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 230 PM EDT Wednesday...

Key Messages:

1) Warm humid conditions will persist through Thursday before
turning cooler Friday.

2) Scattered to numerous showers and thunderstorms expected
through Thursday.

Forecast focus the next 24 hours will be the opportunity for
showers and thunderstorms. Coverage of showers/storms will be
the greatest between now and sunset, then again with the frontal
passage on Thursday.

Regional soundings from 12Z were very moist with PWATs 1.60 to
1.80. Mean wind is from the west-southwest at 20 kts...so
storms are moving a bit faster today compared to
yesterday...20-25 mph forward speed. This should cut down on
residence time of the heavy rain, but with PWATs above normal,
activity will be very rain efficient and still justifies
marginal risk for excessive rainfall and localized flooding.
DCAPE is less than yesterday but trade off will be faster mean
wind, so still think there is modest wind threat with down-draft
wind speeds on the order of 30 kts with potential for isolated
wind damage. Stronger cores may also contain pea size hail.

Weather map shows cold front from the upper Mid-West to North
Texas with Gulf moisture streaming north ahead of the front, the
eastern CONUS bathed in near 70 degree dewpoints. There are a
couple of MCVs embedded within the moist southwest flow ahead of
the front, one of which was moving E along the Mason Dixon, and
the other over the southern Appalachians...both features
providing lift for better thunderstorm organization today,
compared to yesterday. The Vort entering the southern
Appalachians will be the primary focus for thunderstorms across
our CWA through this evening. With the favorable thermodynamic
and dynamic set-up, will maintain high chance for measurable
rainfall through sunset. With PWATs near 2.0 inches, expect high
rain rates...2-4 inches/hr possible. Had some reports
yesterday with the storms producing .80" in 15 minutes.

In general, expecting shower/storm coverage to wane with loss of
daytime heating, with lull in activity before the actual surface
front arrives. Models bring front to our doorstep by daybreak
Thursday so looking at opportunity for increasing shower
activity late tonight across our WV and far western VA
counties. Not sure if the band of showers associated with the
front will be continuous enough to cross the mountains Thursday
or just fade and then redevelop east of the mountains Thursday
afternoon. For now, will maintain high pops areawide Thursday,
in spite of the potential for a hydraulic jump.

Until the front clears the area Thursday, dewpoints will remain
elevated. Given the nature of the airmass, the rain just makes
it more muggy, providing little in the way of evaporational
cooling when it does rain, and downright steamy if the sun is
out.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 230 PM EDT Wednesday...

Key Messages:

1. Drier weather returns Friday and Saturday.
2. Cooler temperatures through the weekend.

An upper level low will drift east of the Great Lakes towards Ottawa
Canada through the period. Shortwaves coming around this low will
bring strato-cumulus clouds across the area Friday and Saturday. Any
measurable rain will be along the western slopes of SE WV and
possibly a sprinkle over the rest of the mountains Thursday night
into Friday.

Dry high pressure will track southeast across Tennessee Friday, then
settle over Georgia/South Carolina Friday and Saturday. With the
Gulf blocked, any disturbance coming from the Plains should only
result in an increase in clouds.

Since the area will remain under the influence of the low in Canada,
cooler than normal temperatures are likely Friday and Saturday. High
temperatures through the period will range from the upper 60s to mid
70s west of the Blue Ridge to the lower 80s east.

&&

.LONG TERM /SUNDAY THROUGH TUESDAY/...
As of 230 PM EDT Wednesday...

Key Messages:

1. Chances for showers and possible storms Sunday and again
Wednesday.
2. Cooler temperatures through the start of the work week.

Models are in agreement with a cold front moving across the area on
Sunday, but differ on rainfall amounts. Since the flow will mainly
be out of the west and high pressure blocking the Gulf through at
least Saturday night, rainfall amounts should be at or under a tenth
of an inch. This front is expected to stall across North Carolina on
Monday then lift north as a warm front on Tuesday. The chance for
rain increases on Wednesday as a disturbance from the Midwest tracks
over the region.

Cooler than normal temperatures expected through the period.
Temperatures will possibly trend back to normal on Wednesday

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
As of 135 PM EDT Wednesday...

Scattered to numerous showers/storms are expected until about
sunset with potential for localized wind gusts 20-30 kts along
with pea hail and heavy rain. Deep convection should wane after
loss of day time heating.

Outside any storms, winds will be southwest 5-12kts a few gusts
to 20kts under VFR broken cloud bases of 3-6kft. A lull in the
storms early tonight with winds subsiding. Fog may develop
overnight but cloud cover and an approaching cold front
associated with more showers may limit this so kept vsbys no
worse than MVFR mainly in the mountains.

Forecast confidence is average on all elements.

EXTENDED AVIATION OUTLOOK...

Passage of a cold front is expected Thursday with scattered
showers and thunderstorms, flight restrictions favoring MVFR (or
lower). Showers/storms could be close to BLF/LWB by 12z Thu.

Friday is expected to be drier and a better probability of VFR
conditions behind the front. A few showers possible Sat-Sun in
the mountains but mainly VFR.

&&

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

&&

$$

SYNOPSIS...PM
NEAR TERM...PM
SHORT TERM...RCS
LONG TERM...RCS
AVIATION...PM