892
FXUS61 KRNK 211050
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
650 AM EDT Thu Aug 21 2025

.SYNOPSIS...
A frontal boundary in the area today will keep the chance for
showers and storms around mainly for the mountains. Meanwhile,
Hurricane Erin shifts further north and east away from the
mainland. High pressure nudges in Friday with another front
moving in this weekend, and changing airmasses behind it for
next week to cooler and drier weather.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 123 AM EDT Thursday...

Key Messages:

1) Confidence is high for scattered showers and thunderstorms
along and west of the Blue Ridge Thursday afternoon. Locally
heavy rain from storms could cause isolated flooding.

Fog and low clouds this morning will give way to a mix of sun
and clouds by afternoon with most of the cloud cover along/west
of the Blue Ridge. A front tracks southward int NC today but
enough upper support and low level moisture combined with higher
pwats will keep the threat for storms around with heavy rain at
times, mainly along and west of the Blue Ridge. Going with a
model blend which has higher probabilities of storms across the
Blue Ridge and just west along the I-81/I-77 corridor, with
little to no chance east of U.S. 29 in the Piedmont of VA.
Temperatures could be a few degrees lower on Thursday compared
to Wednesday due to a more pronounced northeast flow as
Hurricane Erin passes offshore. Highs will range from the mid
70s to near 80 west to the lower to mid 80s east.

Storms will generally be moving to the southeast to south, but
some propagation northward is possible. Movement will be in the
15-20 mph range but some training of storms could lead again to
localized flooding concerns, especially in steeper terrain and
more urban areas.

Showers fade by midnight with high pressure nudging in from the
northwest and Erin offshore allowing for continued northeast
flow.

Clouds will more prominent Thu night along/west of the Blue
Ridge with more clearing in the east.

Lows tonight will be slightly cooler with lower 60s west to mid
60s east. Fog could become an issue where it rained and if the
skies clear out enough.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
As of 100 AM EDT Thursday...

Key Points:

1. Increasing chances of showers/storms each day.
2. Locally heavy rain possible each day, especially over western
portions of the region.
3. Temperatures around to slightly above normal.

A look at the 20 Aug 00Z NCEP Ensemble Mean 500mb Geopotential
Heights shows for Friday/Friday night, low over south central
Canada shifts a bit farther east and deepens. Low pressure will
be over the Gulf of Alaska. High pressure will be centered near
or just north of the Four Corners region. A general weakness in
heights is expected over the East Coast. For Saturday/Saturday
night, the Canadian low deepens between James Bay and the Upper
Peninsula of Michigan with its associated trough axis extending
south into the mid-Mississippi Valley. The general area of
troughiness remains over the East Coast. High pressure with
ridging will remain situated over the western US. for
Sunday/Sunday night, an expanding trough of low pressure
extending south from James Bay to the mid-Mississippi Valley to
the SE US. A ridge is still expected to over much of the western
US, but a bit weaker than twenty-four hours prior.

At the surface, for Friday/Friday night, high pressure will be
positioned over eastern VA/NC. A frontal boundary will be stalled
across the SE US. Low pressure will continue to head east across
southern Canada with an associated cold front trailing southwest
into parts of Upper Mississippi Valley. For Saturday/Saturday night,
high pressure along the east coast shifts into the western Atlantic.
A cold front makes progress eastward, reaching portions of the
eastern Great Lakes region and Lower Ohio Valley during the early
evening on Saturday. For Sunday/Sunday night, the cold front reaches
our region, somewhere around the early evening hours on Sunday. High
pressure builds in behind the front across portions of the Northern
Plains States.

A look at the 20 Aug 12Z NAEFS Ensemble Situational Awareness data
shows 850mb temperatures across our region around +16C on Friday.
For Saturday, little change from the previous day is expected. For
Sunday, values inch slightly higher to the +16C to +17C range.

The above weather patterns offers the following forecast. While high
pressure is expected to be over the coast, anti-cyclonic flow around
this high, paired with a stalled front to our south, will advect
moisture north into primarily western parts of the region on Friday.
This moisture will be realized in the form of both increased cloud
cover and the development of mainly afternoon/evening
showers/storms. Showers/Storms are expected to be more numerous on
Saturday/Saturday night with a cold front approaching from the west,
all the while we maintain a good fetch of moisture into the region.
There is a greater chance the activity will last through Saturday
night, especially over the western half of the region. For
Sunday/Sunday night, look for additional good coverage of
showers/storms with the arrival of the front. By late Sunday night,
the front expected to have cleared the eastern portions of the
region.

With notable pooling of moisture in advance of an approaching cold
front, locally heavy rainfall will be a potential each day,
especially over western sections of the region.

Confidence in the above weather scenario is moderate

&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
As of 100 AM EDT Thursday...

Key Points:

1. No precipitation.
2. Temperatures trending cooler to values five to ten degrees
below normal by mid-week.

A look a the 20 Aug 00Z NCEP Ensemble Mean 500mb Geopotential
Heights shows for Monday/Monday night, a trough continues to amplify
and also shift slightly east, extending from just east of James Bay
south into the Lower Ohio Valley and the SE US. Ridging is still
expected across much of the western US. For Tuesday/Tuesday night,
the axis of the upper trough progresses slightly east, but with the
axis still west of our region as of Tuesday evening. For Wednesday,
the trough axis is expected to be over or just east of our region as
of the early evening hours.

At the surface, for Monday/Monday night a cold front will be east of
the region, extending south from an area of low pressure over
central Quebec. High pressure will be centered over MN/IA with a
ridge axis curving southeast into parts of the Ohio Valley. For
Tuesday/Tuesday night, the center of the high shift southeast to
over IA/IL/MO, with a greater expanse of the ridge axis extending
into our region. For Wednesday, the center of the high shifts to
over the Lower Ohio Valley.

A look at the 20 Aug 12Z NAEFS Ensemble Situational Awareness data
shows 850mb temperatures for Monday trend lower, reaching roughly
+12C to +14C across the region. The low end of this range falls
within the 2.5 to 10 percentile of the 30-year CFSR
climatology. Temperatures continue trending lower for Tuesday.
Values are expected to range from +10C to +12C with the low end
of this range within the 1 to 2.5 percentile for the CFSR
30-Year climatology. For Wednesday, similar values to Tuesday
are expected.

The above weather patterns offers the following forecast. The center
a cool high pressure will progressively approach our region. The
result is expected to be a dry forecast with temperatures about five
to ten degrees below normal by mid-week.

Confidence in the above weather scenario is moderate to high

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
As of 646 AM EDT Thursday...

NOTE: KLWB has issue with observations going out and with none
being transmitted during the night will have AMD NOT SKED in the
TAF.

Variable cigs/vsbys out there this morning fluctuating at times
from VFR to LIFR. Fog was more an issue at BCB and perhaps LWB
but no obs there. Should see improvements to VFR by 15-17z.
Storms will likely fire up again along/west of the Blue Ridge
this afternoon and will have VCTS in for BCB/BLF/LWB, with tempo
1 hr group this afternoon at BLF/LWB. With the passing of
Hurricane Erin off the coast of North Carolina and Virginia on
Thursday, the pressure gradient force may bring gusty winds to
LYH up to 20 knots during the afternoon and evening hours. These
northeast winds should die down by Thu evening.

The afternoon outside of any storms should be VFR, then lower
cigs likely later tonight with IFR or lower possible toward
09-12z Fri.

.EXTENDED AVIATION OUTLOOK...

Coverage of showers and thunderstorms should be reduced on
Friday with most locations staying VFR. Patchy fog may be
possible during early Friday morning and early Saturday morning
due to the moist air mass in place. A stronger cold front will
approach from the northwest this weekend to bring more
widespread showers and thunderstorms. Cooler and drier
conditions should follow by Monday.

&&

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

&&

$$

SYNOPSIS...PW/WP
NEAR TERM...WP
SHORT TERM...DS
LONG TERM...DS
AVIATION...WP