823
FXUS61 KRNK 282356
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
756 PM EDT Fri Jun 28 2024

.SYNOPSIS...
A warm frontal boundary will lift into the area overnight
bringing widespread clouds. High pressure will shift northeast
off the New England coast Saturday, setting the stage for showers
and storms mainly for the mountains Saturday afternoon. A cold
front pushes through late Sunday.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 735 PM EDT Friday...

Key Messages:

1) Warm front overnight will bring widespread stratus.

2) Stratus lingers until mid morning.

3) Chance of convection for western and northern sections
tomorrow afternoon and evening, but severe threat looks low.

No showers have been able to sustain themselves this afternoon
and evening in our forecast area, due to capping and drier air
above 700mb. ESE winds were helping to bring moisture to the
Piedmont this evening, and expect this moisture increase to
continue as a warm front lifts north into the area. We may see a
sprinkle or two overnight, but in general we will see mainly
low stratus, some ~800ft, especially after 2 AM.

Low stratus hangs around through 10 AM or so before beginning
to scatter out and lift. A pre-frontal trough will arrive in the
afternoon and will bring isolated to scattered showers and
storms to the area, mainly west of I-77 and north of I-81.
Severe storms look unlikely here, with less than 20 kts of flow
at 500mb, 0-6km shear of 10 knots or less, and tall skinny
CAPE. The stronger activity will be to our north. That said,
slow storm motions, high PWATs, and deep warm cloud depths will
increase the chance for moderate rain leading to flooding.



As of 200 PM EDT Friday...

Key Messages:

1) Upslope scattered showers/few storms through Friday night.

2) More rounds of scattered showers Saturday

Shower activity has been sparse today so far, but high res
models remain insistent that there will be scattered pockets of
precipitation later this afternoon and evening. They won`t be
particularly heavy or well organized. Moisture advection from a
high to our northeast will cause a mostly upslope event along
the mountains of southwest VA and northwest NC.

As for Saturday, a broad but deepening upper trough becomes more
centrally placed over the eastern CONUS/Mid-Atlantic. This
accompanies an approaching front from Canada/Great Lakes. Storms
will be better organized than Friday, and there is a marginal
risk for severe storms mainly north of the I-64 corridor.

Temperatures will be above normal, and with the aforementioned
moisture advection heat indices in the Piedmont and Southside VA
could approach 100 degrees.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
As of 130 PM EDT Friday...

Key Messages:

1. Hot and Humid Sunday, cooler and drier by Monday.
2. Showers and storms on Sunday, with locally heavy rainfall
possible.
3. Primary threat is damaging wind.

A strong upper level trough will track eastward over the Great
Lakes and into the northeastern US through the weekend, and into
the Atlantic by the beginning of the work week. The associated
surface frontal system will move through the upper Midwest and
Great Lakes region, with the cold front reaching the western
border of the forecast area late Saturday morning, crossing the
area through Sunday. Showers and storms from Saturday may linger
overnight into Sunday, which could impact the day`s high
temperatures, depending on the coverage of residual cloud cover
during the morning hours. This will also play into the potential
for severe weather later during Sunday afternoon and evening,
as cloud cover could limit diurnal destabilization. That being
said, the front will provide a better forcing mechanism for
storm development, and increased deep layer shear could lead to
better storm organization, thus increasing the potential for
storms to become severe. The primary threat with any of these
storms would be strong and damaging winds, with high DCAPE
forecast, and moderate to locally heavy rainfall is still
possible, with above normal precipitable water, indicating
plenty of atmospheric moisture available. Timing of the frontal
passage itself will also influence the potential for severe
storms; if it coincides with the peak diurnal heating, then
severe potential is greater. Another factor that could influence
the possibility of severe storms is the duration of prefrontal
showers and storms that could linger overnight Saturday into
Sunday.

Behind the front, cooler and drier air works into the region as
high pressure builds over the northeast. Temperatures will
fall closer to seasonal normals, but the biggest difference will
be felt with the drier air, and thus lack of humidity. The
surface high will keep the weather quiet Monday and Tuesday,
making for a pleasant start to the work week, after a hot and
humid day on Sunday.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 130 PM EDT Friday...

Key Messages:

1. Increasing temperature and humidity through the period.
2. Showers and storms possible Wednesday into Thursday.
3. Hot and humid weather possible for Independence Day.

Surface high pressure will remain situated over the region
through Tuesday, keeping the weather dry and quiet. By
midweek, an upper ridge starts to build over the southeastern
states, increasing 500mb heights over the area, and temperatures
will start trending warmer. Southwesterly flow ahead of an
approaching cold front will start to advect moisture into the
area, increasing the humidity through the middle of the week as
well. The combination of increasing temperature and humidity
will cause heat indices to rise to the upper 90s to near 100 in
the VA Southside and NC Piedmont around Independence Day. The
return flow around the high could spark showers and
thunderstorms over the southern Blue Ridge, however, coverage is
uncertain at this time, given differences in the long range
deterministic models.

The previously mentioned cold front will slowly approach the
Ohio Valley Thursday, keeping shower and storm chances in the
forecast Wednesday afternoon through Thursday into Friday, as
the region remains in the warm sector until the frontal passage.
At this time, the front looks to orient more west to east, and
stall across the Ohio Valley and Mid Atlantic, which would
continue shower chances through the end of the work week, but
with this being at the end of the forecast period, details are
uncertain, and thus forecast confidence is lower late in the
week.

&&

.AVIATION /23Z FRIDAY THROUGH WEDNESDAY/...
As of 710 PM EDT Friday...

Ceilings will lower to MVFR/IFR 07-09Z at all terminals as a
warm front moves through. We may get a sprinkle or spot of
drizzle overnight, but for the most part kept ceilings above 1
kft, except for DAN which looks to have the better easterly
flow. However, LYH, ROA, and BCB will also flirt with sub-IFR
for a few hours. Ceilings improve after 14-16Z, scattering out
and/or lifting for a few hours before afternoon convection
begins.

Expect TSRA to be isolated, but included -TSRA at BCB, ROA, BLF,LWB
and where neighborhood probabilities are higher for at least
VCTS/CB for a few hours Sunday afternoon/evening.

Confidence in the above scenario is moderate.


EXTENDED AVIATION OUTLOOK...

A greater coverage of showers/thunderstorms and associated MVFR
flight conditions are possible Sunday morning as a cold front
nears, then the highest chances moves to the Piedmont in the
afternoon, possibly affecting LYH and DAN.

Monday and Tuesday appear to be VFR as high pressure works in
from the north. On Wednesday there is a chance of -TSRA in the
mountains as a warm front and pre-frontal trough nears.

&&

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

&&

$$

SYNOPSIS...VFJ/WP
NEAR TERM...SH/VFJ/WP
SHORT TERM...AS
LONG TERM...AS
AVIATION...SH