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850
FXUS61 KRNK 041927
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
327 PM EDT Tue Jun 4 2024

.SYNOPSIS...
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Warm humid conditions will persist through Wednesday with an
opportunity for showers and thunderstorms. A cold front
will cross the area Thursday, temperatures cooling for the
weekend. A brief break in the wet weather pattern is expected
behind the front on Friday and Saturday.
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&&

.NEAR TERM /THROUGH WEDNESDAY/...
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As of 1030 AM EDT Tuesday...

Key Messages:

1. Warm and humid.

2. Scattered showers and thunderstorms.

3. Marginal Risk of excessive rainfall, localized flash
flooding possible.

Upper air soundings support SBCAPE ranging from 1500 j/kg over
the mountains to 2500 j/kg over the piedmont through this
evening...enough buoyancy for scattered showers and
thunderstorms. Mean wind ranges from 6-12 mph out of the
southwest...so expecting slow cell movement and potential for
localized heavy rain. DCAPE near 700 j/kg also suggest some of
the stronger storm cores will contain modest downdraft winds.
The ROA ASOS has already sampled one of these gusts...observing
30 kts just after 2PM this afternoon.

For tonight, our area will continue to be under the influence of
a weak upper level ridge, although the axis is shifting to the
east and allowing for increased southwest flow aloft. The
southwest flow contains impulses aloft, short wave energy,
which will enhance precipitation chances over the next 24
hours. Current airmass features PWATs running 1.2 to 1.5 inches,
and these numbers are expected to increase into Wednesday per
increasing moist southwest flow. Temperatures tonight will
remain mild with lows mainly in the 60s. Dewpoints also in the
60s suggests a moist night with high humidity and potential for
patchy fog.

For Wednesday, much of the day is expected to be mostly cloudy,
especially over the mountains. Short wave trough may introduce
showers across the mountains early, then become more prolific
during the afternoon as CAPE increases over the piedmont. Attm
thinking weather hazards Wednesday will be mainly from the
localized heavy rain. Not sure that we see enough sun to
promote severe, but can`t rule out some healthier downdraft
winds similar to what occurred with the 30 kt gust at ROA Tue.
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&&

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

Key Messages:

1. Moderate to heavy rain may lead to localized flooding Wednesday.
2. Warmer than normal temperatures through Thursday, cooler Friday.

A negative-tilted trough over the Great Lakes will push a pre-
frontal trough over the region Wednesday. Timing of this trough will
help determine the areal coverage of strong to severe storms. As of
now, models have convection coming across the mountains after
sunset, which would limit intensity due to loss of heating. However,
momentum of these storms coming across the southern Ohio Valley may
maintain as this line continues to move through an unstable airmass.
At this time, the severe threat is low, but above normal PWATs
will lead to a marginal risk of flooding from excessive rainfall.

The surface front will move across the area Thursday. Some modest
instabilities may be present to trigger a few storms in the piedmont
Thursday afternoon. Friday looks to be dry, but breezy given the
decent cold air advection behind the front. Cooler and drier air
works its way into the region following the frontal passage, so
temperatures will drop a few degrees for Friday and heading into the
weekend.
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&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
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As of 200 PM EDT Tuesday...

Key Messages:

1. Cooler temperatures through the weekend.
2. Chances for afternoon showers and storms continue.

The mid level trough will be situated over southern Canada and the
eastern US through the weekend, with a few shortwaves rotating
through the trough, keeping chances for showers and possible storms
each afternoon and evening in the forecast, especially over the
mountains. Some long range models are showing a surface low and cold
front developing in the south central Plains by late Saturday,
reaching the Mid Atlantic by Sunday, bringing another round of heavy
rain and possible storms. However, with considerable differences in
the models with the evolution of the upper trough over southern
Canada, there is uncertainty in the forecast for the beginning of
the work week. That being said, there is potential for unsettled
weather to continue into Tuesday.

Temperatures will be on the cooler side through the weekend, near to
a few degrees below normal, following the passage of the cold front
during the week, and dewpoints will drop a few degrees as well. By
the beginning of the work week, temperatures will start gradually
warming to near normal.
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&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
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As of 130 PM EDT Tuesday...

Expect cloud build-ups with widely scattered showers/storms
through sunset, favoring both mountains and piedmont, but with
little organization. Downdraft wind gusts up to 30 kts may be
associated with some of the stronger storm cells. The activity
is expected to diminish after sunset, although may linger later
that usual due to lift from approaching shortwave energy aloft.

Fog will likely form late tonight with MVFR to IFR at most
sites, highest confidence for LWB to get fog.

Short wave trough will cross the forecast area Wednesday and
Wednesday night resulting in greater coverage of showers and
thunderstorms. Sub-VFR is favored Wednesday due to low cigs and
the abundance of shower activity with variable visibilities.


EXTENDED AVIATION OUTLOOK...

Passage of a cold front is expected Thursday with scattered
showers and thunderstorms, flight restrictions favoring MVFR (or
lower).

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

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

&&

$$

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