469
FXUS61 KRNK 091803
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
203 PM EDT Thu May 9 2024

.SYNOPSIS...
A low pressure system and cold front crossing through the Ohio
Valley and Mid Atlantic region will bring scattered showers and
isolated to isolated thunderstorms this evening. A second push of
cooler air and gusty winds will bring clouds and showers to the
mountains Friday through Sunday. Dry high pressure is expected on
Monday, followed by a widespread probability of precipitation
Tuesday and Wednesday.

&&

.NEAR TERM /THROUGH FRIDAY/...
As of 135 PM EDT Thursday...

Key messages:

   - Scattered showers and isolated thunderstorms
   - Breezy tonight and Friday

Satellite images indicated much of the fog and low clouds from
earlier this morning have eroded, as well as the presence of a
thin layer of cirrus. Enough sunshine getting through to bring
surface based CAPE to 500-1000 J/kg. Best coverage of
precipitation will be along and north of I-64 west of Lexington
and north of Route 460 between Roanoke and Lynchburg.

As the cold front passes through tonight surface and low-level
winds turn from the southwest to west, then with a second short
wave, winds become northwest Friday afternoon. GFS and 3km NAM
were both showing to 50 to 60 knot low level jet develops
overnight and into Friday morning. The jet combined with cold
air advection as 850 mb temperatures drop from around +12 into
the +4 to +8 range on Friday, will result in wind gusts in the
30 to 40 mph tonight at higher elevations. Once mixing begins
on Friday morning, much of the area will have a gusty wind.

Due this good upslope, will have clouds in along the western
slopes of the central Appalachians tonight and through the day
Friday. Will keep the chance of showers on Friday. Cannot rule
out isolated thunderstorms on Friday as cold air aloft will
provide favorable lapse rates and some enhanced instability.

Combination of MAV/MET guidance for lows tonight and highs on Friday
look reasonable.


&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
As of 1245 PM EDT Thursday...

Key Messages:

1) Confidence is high for cooler conditions this weekend.

2) Mountain rain showers will be possible during Saturday afternoon
into Sunday morning.

A cold front will exit offshore on Friday night, while a broad upper
level trough enters the Mid Atlantic. After the recent stretch of
warm and moist conditions, temperatures will turn noticeably cooler.
Morning lows throughout this weekend should fall into the 40s for
most locations with some upper 30s likely in the sheltered mountain
valleys. The wind will become breezy from the west to northwest with
gusts of 20 to 30 mph possible in the higher elevations during the
daytime hours of Saturday and Sunday.

Rotating around the periphery of the broad upper level trough will
be a shortwave trough that should dive southeastward from the Great
Lakes on Saturday. As it reaches the Appalachian Mountains by
Saturday afternoon, rain showers will spread along and west of the
Blue Ridge. The upslope northwest flow should keep the showers
lingering through Saturday night before fading by Sunday morning.
High pressure will build eastward by late Sunday to provide dry
weather throughout the Mid Atlantic.

&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
As of 1245 PM EDT Thursday...

Key Messages:

1) Confidence is high for warmer conditions by next week.

2) Daily chances of showers and thunderstorms will return with the
highest odds possible by Tuesday.

Monday should start dry with high pressure across the Mid Atlantic.
The high should head offshore later in the day to provide warm air
advection and moisture advection from southwest flow. However, this
increase in warmth and moisture will combine with an approaching low
pressure system in the central Mississippi River Valley to spark
shower and thunderstorm chances over the next couple days. Isolated
convection may reach the southern Blue Ridge and far southwest
Virginia by Monday night, but the greatest odds for showers and
thunderstorms appears to be Tuesday. Moisture will linger through
Wednesday, but the abundant cloud cover might somewhat limit the
thunder chances. Weak high pressure could bring a brief reprieve
during Thursday morning, but another low pressure system may
approach from the west by late Thursday.


&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
As of 200 PM EDT Thursday...

Satellite images indicated much of the LIFR fog and MVFR clouds
from earlier this morning have eroded, as well as the presence
of a thin layer of cirrus. Enough sunshine getting through to
bring surface based CAPE to 500-1000 J/kg. Best coverage of
precipitation will be along and north of I-64 west of Lexington
and north of Route 460 between Roanoke and Lynchburg. For now
have VCSH at KLWB and VCTS at KLYH.

As the cold front passes through tonight surface and low-level
winds turn from the southwest to west, then with a second short
wave, winds become northwest Friday afternoon. GFS and 3km NAM
were both showing to 50 to 60 knot low level jet develops
overnight and into Friday morning. The jet combined with cold
air advection, will result in wind gusts up to 45 kts tonight
at higher elevations. Once mixing begins on Friday morning,
much of the area will have a gusty wind in the to 20 to 30 knot
range.

Due this good upslope, will have clouds in along the western
slopes of the central Appalachians tonight and through the day
Friday. Will keep the chance of showers on Friday. Cannot rule
out isolated thunderstorms on Friday as cold air aloft will
provide favorable lapse rates and some enhanced instability.


Average confidence for ceiling, visibility, and wind.


Extended Aviation Outlook...

Expecting MVFR showers, mainly in the mountains on Saturday. Some
upslope mountain showers may occur Saturday night. VFR
conditions are expected Sunday and Monday under dry, high
pressure. The probability of precipitation and sub-VFR ceilings
and visibilities increases on Tuesday ahead of a low pressure
system in the central United States.

&&

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

&&

$$

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