130
FXUS61 KRNK 251840
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
240 PM EDT Tue Jun 25 2024

.SYNOPSIS...
A cold front crossing the region on Wednesday will bring a return of
showers and thunderstorms, especially in the afternoon and evening.
Hot and humid weather is a expected through the end of the week,
with a heat index around 100 in the Virginia piedmont on Wednesday.
A low probability of thunderstorms remains in the forecast for
Thursday through Saturday.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
As of 230 PM EDT Tuesday...

Key messages:

    - Dry and less humid tonight
    - Hot and humid weather returns Wednesday

Scattered cumulus had developed over the region this afternoon.
This cloud cover will erode with the loss of heating once the
sun sets, but higher clouds from thunderstorms in the Ohio will
spread into the mountains.

As surface high pressure weakens, low level flow becomes southwest
and brings back surface dew points in the 60s and warmer 850 mb
temperatures. The temperature/dew point combination will result
in a heat index from the upper 80s to around 100 Wednesday
afternoon. A bit too much residual cloud cover in the morning
and cumulus development in the afternoon to reach the full
potential of the warmer airmass. Kept the maximum temperature in
the mid to upper 90s in the piedmont.

Bufkit forecast soundings showed Convective Available Potential
Energy in the 1500-2000 J/kg range in the afternoon. Based on the
SPC HREF ensemble...a majority of the thunderstorm development
will be after 18Z/2PM. CSU machine learning and SPC HREF showed
the potential for strong to damaging winds in central northern
Virginia late in the afternoon.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 215 AM EDT Tuesday...

Key Messages:

1) Confidence is high for hot and humid conditions on Wednesday.

2) Showers and thunderstorms are possible each afternoon with the
best chance during Wednesday and Thursday.

With high pressure situated offshore to provide a southwest flow
across the Mid Atlantic on Wednesday, hot and humid conditions will
return as dewpoints rise into the 60s and temperatures soar into the
mid 80s to the upper 90s. The heat index could briefly reach between
100 and 105 degrees along and east of a line from Danville to
Lynchburg. This increase in heat and humidity will allow CAPE to
rise up to 2,000 J/kg as a cold front approaches the Ohio River
Valley. Consequently, showers and thunderstorms will develop during
Wednesday afternoon and evening. Some of the storms may become
strong enough to pose a risk of severe weather with damaging winds
as the main threat.

High-resolution models show a line of convection firing along the
Blue Ridge on Wednesday afternoon and moving east to the Piedmont.
Meanwhile, another line of storms will enter West Virginia just
ahead of the cold front during Wednesday evening and enter Virginia
by early Wednesday night. The cold front should cross the Mid
Atlantic on Thursday, which will allow more showers and
thunderstorms to fire across the Piedmont. Drier air will follow
after the frontal passage, but high pressure should pass to the
north on Thursday night to steer the flow back towards the east. As
a result of the increasing moisture convergence along the southern
Blue Ridge, more storms may occur for Friday afternoon and evening.
Temperatures may only dip a few degrees during Thursday and Friday,
but values should still remain above normal.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 215 AM EDT Tuesday...

Key Messages:

1) Confidence is high for temperatures staying above normal
through the upcoming weekend and into early next week.

2) A chance of showers and thunderstorms will continue each
afternoon, but the highest odds occur on Sunday.

The flow should turn towards the south on Saturday in response to a
cold front entering the Ohio River Valley, and the increase in warm
air advection and synoptic lift will yield scattered afternoon
showers and thunderstorms in the mountains. However, the highest
chance and greatest coverage of convection occurs on Sunday when the
cold front approaches the Appalachian Mountains. Strong storms may
be possible during Sunday afternoon into early Sunday night. High
pressure will provide drier air by late Sunday night into early
Monday morning, but the cold front may slow down as it tries to push
southward towards South Carolina. The close proximity of this
frontal boundary may be enough to keep a low chance of afternoon
showers and thunderstorms in North Carolina.

&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
As of 235 PM EDT Tuesday...

Scattered VFR cumulus had developed over the region this
afternoon. This cloud cover will erode with the loss of heating
once the sun sets, but higher clouds from thunderstorms in the
Ohio will spread into the mountains.

As surface high pressure weakens, low level flow becomes southwest
and brings back surface dew points in the 60s and warmer 850 mb
temperatures. Bufkit forecast soundings showed Convective
Available Potential Energy in the 1500-2000 J/kg range in the
afternoon. Based on the SPC HREF ensemble...a majority of the
thunderstorm development will be after the 18Z/2PM end of the
TAF forecast period.

Average confidence in ceiling, visibility, and wind.

EXTENDED AVIATION OUTLOOK...

Scattered thunderstorms with potential MVFR ceiling and
visibility, along with strong wind gusts, are expected Wednesday
afternoon into early Thursday morning.

VFR conditions expected through much of the week, with the only
exception being areas of valley fog in the early morning hours,

Isolated showers and thunderstorms are possible again each
afternoon and evening Thursday through Saturday.

A greater coverage of thunderstorms and associated MVFR flight
conditions, is expected along and ahead of a cold front on
Sunday.


&&

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

&&

$$

SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...PW
LONG TERM...PW
AVIATION...AMS/BMG