743
FXUS61 KRNK 181412
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
1012 AM EDT Sun Aug 18 2024

.SYNOPSIS...
A cold front moves across the mid-Atlantic today reaching the
coast by Monday morning. High pressure builds in midweek with
less humid and cooler air.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 1005 AM EDT Sunday...

Minimal changes were made to the forecast this morning, mainly
just to account for current conditions. A few light showers
ongoing this morning, but the main surface front still remains
to the west over West Virginia and eastern Kentucky. Cloud cover
will continue to inhibit warming a bit, so still a bit of
uncertainty on the coverage of afternoon storms, especially
across the Piedmont of Virginia and North Carolina.



As of 125 AM EDT Sunday...

Key Messages:

1) Keeping storms in the forecast today but coverage again looks
scattered. Could see a few strong storms in the Piedmont.

Lee trough and shortwave energy will keep a few showers around
early this morning and will likely see more of coverage today
with the front, but locations and high-res model solutions
indicate a scattered pattern with best coverage looking to be
across the Mountain Empire of SW VA into the NC mountains and
across the Piedmont. Storm parameters are leaning toward a small
chance of severe in the Piedmont mainly east of Lynchburg-
Martinsville.

Storms should become less by dusk, though as upper trough axis
shifts to the area late tonight with upslope low level flow
scattered showers will likely linger through the night in the
WV/far SW VA and NC mountains.

Should see mix of sun and clouds today with more sun east, so
highs will again be close to normal in the Piedmont with upper
80s, but more clouds in the mountains should have highs in the
70s, except some lower 80s in the New River Valley.

Until the front really clears east, the drier air lags until
after this period, so airmass will not change too much tonight
with lows in the 60s.

Forecast confidence is high on sky cover/temps/winds, but
average on storm coverage and severe threat.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
As of 400 AM EDT Sunday...

Key Messages:

1). Scattered showers and thunderstorms Monday and much cooler,

2). Extended period of dry weather with unseasonably cool
temperatures begins Tuesday.

A deep and high amplitude upper trough developing during the
past several days across the eastern U.S. will slowly progress
eastward through the period. The region will be located on the
dynamic eastern side of the trough Monday with cyclonic flow and
relatively cold air aloft. This will result in fairly steep
lapse rates and lower than usual freezing levels for August.
This should result in scattered to numerous showers and even
some thunderstorms by afternoon. SPC has a marginal threat over
the eastern parts of the CWA Monday with the main threat being
wind gusts. However, I could see sub severe hail in the strong
cells Monday afternoon. Any convective activity should dissipate
quickly Monday evening with the loss of diurnal heating. In
addition, the upper trough will also drift east of the area
Monday night into early Tuesday.

Tuesday will being a period of dry and much cooler weather
conditions than we have seen since late spring. A large area of
Canadian high pressure will settle over the Ohio Valley and
Mid-Atlantic by midweek with dewpoints dropping into the 40s and
50s. Under this dry air mass, nighttime temperatures will feel
more like mid-September than mid-August with lows dipping well
into the 40s for the western mountain valleys and 50s even
across the Piedmont. These low temperatures will average around
5-10 degrees below normal midweek. With abundant sunshine, it
will still be pleasantly warm during the afternoon, but
nonetheless highs mostly in the 70s will average around 5
degrees below normal.

/Confidence Levels in Forecast Parameters/
- Moderate Confidence in Temperatures,
- High Confidence in Precipitation Probabilities,
- Moderate to High Confidence in Wind Direction and Speed,
- Low to Moderate Confidence in Thunderstorm Potential.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 430 AM EDT Sunday...

Key Messages:

1). Extended Period of No Precipitation Expected,

2). Below Normal Temperatures Through Friday, Trending Toward
Normal or Slightly Above Normal by the Weekend.

Surface and upper ridging will evolve through the period and
dominate the synoptic pattern. No precipitation expected through
the period and limited cloud cover. A rather enjoyable period of
weather for August.

Initially the air mass will be unseasonably cool and dry with
dewpoints in the 40s mountains and mainly 50s elsewhere. 850mb
temperatures drop into the 5-10C range allowing unseasonably
cool temperatures in the 40s and 50s at night with just 70s for
most of the area in the daytime. Some of the higher mountain
elevations may not even get out of the 60s. Abundant sunshine
will help to offset the fall- like chill. By the end of the
week, however, a 598dm upper ridge across the central U.S. will
begin to drift eastward. Very warm temperatures aloft in the
+20C or better will slowly drift in our direction by the
weekend. Thus, temperatures will warm back well into the 80s
before the end of August. Summer is not quite over just yet!

Confidence Levels in Forecast Parameters
- Moderate Confidence in Temperatures,
- High Confidence in Precipitation Probabilities,
- Moderate to High Confidence in Wind Direction and Speed.

&&

.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
As of 645 AM EDT Sunday...

Mainly VFR this morning but low clouds/fog possible BLF.

All sites should become VFR by 14-15z with scattered/broken
cumulus in the afternoon mixed with high clouds. Frontal
boundary swings across and will have VCTS at all sites, except
ROA/BCB per models showing minimal coverage in these areas
today. Amendments likely with radar trends during the day.

Winds will be southwest to west at 6-11kts after 14z.

.EXTENDED AVIATION OUTLOOK...

Late Sunday night could see some fog/low clouds at BLF/LWB/BCB.
Will be dependent on how much clearing takes place if at all
above the low levels. Upper trough axis should keep scattered
showers/storms around Monday but looking at mainly VFR through
the week. Exception would be with showers Monday and any late
night fog.

&&

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

&&

$$

SYNOPSIS...WP
NEAR TERM...BMG/WP
SHORT TERM...VFJ
LONG TERM...RAB
AVIATION...RAB/WP