503
FXUS61 KRNK 070258
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
1058 PM EDT Thu Jun 6 2024

.SYNOPSIS...
A cold front will move through the region tonight, and bring a
drier and cooler airmass to our area as we head into the
weekend. Until the passage of the front, isolated showers may be
seen, especially in areas west of the Blue Ridge.

&&

.NEAR TERM /NOW THROUGH FRIDAY/...
Issued at 1058 PM EDT Thu Jun 06 2024

Latest surface analysis shows a cold front extending from
Central Virginia into the North Carolina Piedmont. Drier air
will continue filtering into the region behind the front,
although it may be slightly slower than expected. Based on this, I
made a few adjustments to the gridded database. But overall,
the forecast remains on track late this evening.

Issued at 811 PM EDT Thu Jun 06 2024

The showers and thunderstorms associated with a deeper plume of
moisture and a passing prefrontal trough have moved east of the
region early this evening. The (legit?) surface front, which will
bring a drier airmass into the region, was still moving eastward
across the Ohio Valley. It`s still expected to move through our area
later tonight. Until that happens, we could still see some isolated
showers, especially west of the Blue Ridge. I`ve made some minor
adjustments to precipitation probabilities/timing based on the
latest available guidance. Other than this, the ongoing forecast
seems to be in decent shape and no additional changes were made.

I did contemplate the possibility of some late night/early morning
(river valley) fog, mainly west of the Blue Ridge. I ultimately
decided against it because it still looks like the wind speeds
should remain up through most of the night. I`ll continue to monitor
trends through the evening.

As of 200 PM EDT Thursday...

Key Messages:

1) A few strong to severe storms possible east of Blue Ridge
through this evening...then partial clearing.

2) Drier and cooler weather arrives Friday

Forecast focus is on the passage of a cold front this evening
promoting showers and thunderstorms. Main threat for
thunderstorms is east of the Blue Ridge where surface heating
has allowed for higher buoyancy to support deep convection.
Pre-frontal trough lee of the Blue Ridge will likely enhance
storms as they move east across the piedmont so expect storm
activity to increase across southside VA and into the piedmont
before exiting the CWA early this evening.

Models are in good agreement on timing having best chance of
showers/storms through 21Z/5PM before exiting the CWA. After
that should see partial clearing with winds shifting to the
west. The front is actually coming through in pieces...the main
push of moisture this evening, followed by a secondary front
associated with the drier air late tonight. Aside for a few
isolated showers overnight the overall trend will be for drying.
Friday should feature a much drier day with winds out of the
west or northwest and associated with falling dewpoints. It will
be breezy at times with gusts up to 25 mph.

&&

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

Key Points:

1. Around or slightly above normal temperatures.
2. Scattered showers on Sunday into Sunday night.

A look at the 6 June 00Z NCEP Ensemble Mean 500 mb Geopotential
heights shows a persistent upper low centered near the
Ontario/Quebec border through the period. However, a couple
associated shortwave troughs are expected to progress around this
low and cross our region. The first of these is expected Friday
evening just east of the region, with the second on Sunday evening.
At the surface, a cold front is expected to extend from far eastern
VA southwest along the coast of the Carolinas Friday evening. By
Saturday, a weak high pressure center moves into the area. On
Sunday, our next cold front is expected to cross the area and be
east of the region by the end of Sunday night.

Output from the 6 June 00Z Ensemble Situational Awareness Table
shows 850mb temperatures averaging +16C on Saturday, +14C to +16C
for Saturday and +12C to +14C for Sunday. Precipitable Water values
are expected to average 0.75 inches or slightly less Friday night
into Saturday and 1.25 inches Sunday. The values Friday night into
Saturday fall within the 2.5 to 10 percentile range of the 30-year
climatology.

The above weather scenario points to a period with around or
slightly above normal temperatures. Primarily dry conditions are
expected through Saturday night. Sunday into Sunday night, look for
a return of showers with the passage of the cold front and residual
activity from upslope northwest flow across Southeast West Virginia
late Sunday night. Thunderstorm potential looks low with forecast
CAPE on most models under 500 J/kg.

Confidence in the above weather pattern is moderate to high.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 130 PM EDT Thursday...

Key Points:

1. Temperatures trending from slightly below to slightly above
average.
2. While precipitation chances will not be zero through the period,
the vast majority of the region will be dry.
3. While at most scattered in coverage, the mountains have the
greatest potential to experience showers.

A look at the 6 June 00Z NCEP Ensemble Mean 500 mb Geopotential
heights shows a persistent long wave trough extending from southeast
Canada into the Ohio Valley. Each day Monday through Thursday, the
trough is expected to remain nearly stationary, but there will a
gradual trend towards less amplification as ridging across western
CONUS shifts into the center of the nation. At the surface, on
Monday, a cold front will be positioned along the Atlantic coast.
High pressure will be centered across the Central Plains States and
Upper Mississippi River Valley. On Tuesday and into Wednesday, a
ridge of high pressure will be over the region. On Thursday, is
still expected to be over the general area, but potentially trending
weaker.

Output from the 6 June 00Z Ensemble Situational Awareness Table
shows 850mb temperatures around +14C for Monday, +14C to +16C for
Tuesday, +16C on Wednesday and a little over +16C for Thursday.
Precipitable Water values on Monday are expected to average 1.00
inch on Monday and Tuesday, 1.25 inch on Wednesday and 1.00 to 1.25
inches for Thursday.

The above weather scenario points towards a time period with limited
precipitation chances and temperature around or slightly cooler than
normal for this of year through Tuesday. Around or slight above
normal temperatures are expected Wednesday into Thursday. The best
chances for showers will come on Monday, and perhaps Monday night
while we are still within a northwest flow pattern. For Tuesday
through Thursday, while precipitation chances will be low, they are
not expected to be zero. While we expect a general region of surface
high pressure over the region, additionally over the area aloft will
be a weakening upper level trough. The trough, and its expected
steep lapse rate aloft, will help promote convection development
above where any fledgling towering cumulus develop during the peak
heating of the afternoon. Coverage will be isolated with the vast
majority of the area receiving no precipitation.

Confidence in the above weather pattern is moderate.

&&

.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
Issued at 811 PM EDT Thu Jun 06 2024

A SCT-BKN deck of mostly Sc, with most bases around 040, will
continue affecting areas (mainly) W of the Blue ridge this
evening. ISOLD -SHRA may be seen at terminals in this region,
as an approaching cold front interacts with lingering moisture.
I`ve included VCSH in the TAFs for a couple of hours for my SE
WV terminals due to my greater confidence in a low probability
event. As the front moves W- E across the forecast area later
night, drier air will move into the region. This will end the
possibility of precipitation and decrease cloud cover. Overall,
flight categories should remain VFR through the 07/2400 UTC.

A dominant W wind, with speeds mostly in the 5-10 kt. range, is
expected to continue overnight. This should keep much in the way of
valley BR development at bay. Expect an increase in wind speeds
after sunrise Friday, with occasional gusts to 20 kts. possible.


OUTLOOK FRIDAY NIGHT THROUGH TUESDAY...

Friday night-Saturday night: CAVOK conditions. No restrictions
expected.

Sunday-Monday night: A storm system could bring ISOLD-SCTD SHRA/TSRA
to the region. Reductions in CIGs/VSBYs, which could result in
flight restrictions, will be possible.

Tuesday: Expect lowering probabilities of SHRA/TSRA as high pressure
builds into the region. No restrictions anticipated.

&&

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

&&

$$

SYNOPSIS...DB/PM
NEAR TERM...DB/PM
SHORT TERM...DS
LONG TERM...DS
AVIATION...DB