059
FXUS61 KRNK 121732
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
132 PM EDT Sat Jul 12 2025

.SYNOPSIS...
The weather pattern will generally remain unchanged through next
week. With a warm and moist airmass lingering across the
region, expect isolated to scattered shower and thunderstorms
each afternoon and evening. Temperatures across the area will
generally run around or just above normal values for this time
of year.

&&

.NEAR TERM /THROUGH SUNDAY/...
As of 110 PM EDT Saturday...

Key Message:

1) Widely scattered storms today, but more concentrated
along/near the Blue Ridge. Frequent cloud to ground lightning
and localized flooding the main hazards.

Radar depicting a couple of robust-sub severe storms, over
Patrick county, and one that has weakened in Wilkes. The 12z 3km
NAM and FV3 initialized this fairly well but convection has been
developing about 1-2 hours earlier than model forecasts the last
couple of days.

Leaning toward those two models and mesoanalysis, should sit
with high chance to low likely pops around the Blue Ridge and
just east. Storms are moving east at 10-15mph. There is some
weak upper divergence, but main upper waves are further west
over southwest KY. DCAPEs are slightly higher than yesterday in
the 900-1100 J/kg range, so any storms that can grow will be
capable of some stronger potentially severe wind gusts.

As we head into the evening the convection should wane somewhat
but upper support moving across the central Appalachians could
bring enough forcing for showers/storms into the late night
over our WV counties.

Fog may still be an issue where it rains, but cloud cover
upstream from this next wave may hold off on widespread
coverage.

Sunday could be more coverage as surface front reaches the
central Appalachians into the TN Valley in the late afternoon,
while some slight lowering of 5h heights and strong vort move
across during the peak heating. As such have higher pops,
especially in the north and west (I-64 to the far SW VA
mountains).

Again storm motion and some multi-cell clusters could bring
localized flooding, but not enough coverage at this time to
warrant a flood watch. Severe threat is marginal as well, with
damaging winds the main threat, and if cloud cover moves into
the mountains earlier, the severe threat will be better in the
Piedmont.

Not really seeing much need to deviate from previous forecast
and model blend on temps as airmass remains the same, expecting
highs Sunday in the lower 90s east to lower to mid 80s west. Did
adjust dewpoints in the east down as enough mixing has been
keeping them lower than model blend, and this in turn will keep
heat indices below advisory levels but still around 100 degrees
in the Piedmont and perhaps Roanoke.


&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
As of 1230 PM EDT Saturday...

Key Points:

1. Daily chances of showers/storms.
2. Isolated locally heavy rainfall/flooding possible.
3. Above normal temperatures.

A look at the 12 Jul 00Z NCEP Ensemble Mean 500mb Geopotential
Heights shows for Sunday night a longwave trough over Canada with
its axis extending from Hudson Bay to the western Great Lakes
region. Elsewhere across CONUS, expect a broad w-e oriented region
of high pressure. For Monday/Monday night, expect little change from
a synoptic standpoint. The Canadian longwave trough holds firm. What
changes a bit is the position of shortwave troughs within the
broader longwave pattern. By the evening hours, the axis of one
shortwave trough is expected to be over Quebec/New England with
another over British Columbia and the Pacific NW. Broad ridging
covers the southern half of CONUS. For Tuesday/Tuesday night, again,
little change other than the position of the shortwave troughs
within the greater longwave pattern. The one over New England is
expected to be closer to Newfoundland. The one over the Pacific NW
advances to the Northern High Plains. Another shortwave trough moves
onshore the Pacific NW.

At the surface, a small region of weak low pressure is expected to
be eastern portions of VA/NC/SC Sunday night into Monday all the
while high pressure holds fast around it from southeast through
west. A cold front will also approach and cross into our region
during this same time period. For Monday night through Tuesday
night, while high pressure will remain stationary to the southeast,
the cold front will stall and/or wash out over our region.

A look at the 12 Jul 00Z NAEFS Ensemble Situational Awareness data
shows 850mb temperatures will range from +19C to +21C, across
the region. Those areas within the top end of this range will
experience readings within the 90 to 97.5 percentile of the
30-year climatology.

The above weather patterns offers the following forecast. The region
will continue to be within an airmass that offers above normal
temperatures and plenty of moisture. At least diurnal convection is
expected during this period of the forecast. With the introduction
of a front across the area, especially the southern half, there will
be another source of a lifting mechanism and convergence zone to
entertain a better concentration of showers/storms, during not only
the daytime, but a focus to continue them into the overnight hours.
The front will also be a place to watch for locally heavy rainfall
which could lead to isolated flooding.

Confidence in the above weather scenario is moderate to high with
the biggest question mark being to exact location of the front each
day.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 1230 PM EDT Saturday...

Key Points:

1. Threat of daily showers/storms continues.
2. Isolated locally heavy rain/flooding concern, especially Friday
into Saturday.
3. Above normal temperatures.
4. Heat Index values around 100F far eastern areas Thurs-Sat.

A look a the 12 Jul 00Z NCEP Ensemble Mean 500mb Geopotential
Heights shows for Wednesday/Wednesday night, we are expecting a
small southern shift in the base of a longwave trough over Canada --
reaching the northern third of CONUS by the evening hours. Shortwave
troughs with the broader pattern are expected over the Upper
Mississippi River Valley and the Pacific NW. Much of the southern
half of CONUS will still under the influence of a broad ridge of
high pressure. For Thursday/Thursday night, little change is
expected on a synoptic scale. Ensemble averaging starts to washout
the weaker shortwave troughs. For Friday/Friday night, the same
general pattern is expected with a longwave trough over Canada and a
broad ridge over much of the US south of 40 N latitude. A couple of
small changes are expected to be a stronger shortwave trough within
the broad longwave trough over British Columbia. Additionally, the
ridge is expected to strengthen over SE CONUS. On Saturday, little
chance is expected as compared to Friday. The center of the ridge
may shift west to over south-central CONUS.

At the surface, a weak front will remain over the area on Wednesday,
before lifting north of the region by Thursday. A ridge of high
pressure parked to our southeast will help maintain an anti-cyclonic
flow of moisture into our region from off both the Atlantic and the
Gulf. Friday into Saturday, a cold front will approach and then
cross our area.

A look at the 12 Jul 00Z NAEFS Ensemble Situational Awareness data
shows 850mb temperatures Wednesday-Saturday around +18C to
+20C.

The above weather patterns offers the following forecast. With a
frontal boundary remaining over the region on Wednesday, a similar
concentration of showers/storms as compared to Tuesday is expected.
With the front moving north of the area by Thursday, we may briefly
return to a diurnal coverage of showers/storms. However, this will
be short lived with the approach and then return of a cold front to
the area Friday into Saturday. Temperatures will still be above
normal for this time of year. Combined with high humidity, late
afternoon Heat Index values may be around 100F across the far
eastern sections of the region during this time, especially from
Thursday through Saturday.

Confidence in the above weather scenario is moderate to high.

&&

.AVIATION /17Z SATURDAY THROUGH WEDNESDAY/...
As of 124 PM EDT Saturday...

VFR conditions are expected to prevail through much of the TAF
period. Allowed for VCTS at most sites and tempo 1-3 hr time
window for storms especially at ROA/BCB based on model/radar
trends. Storms could bring gusty winds and sub-VFR
ceilings/vsbys. Convection should wane after 00z/Sun.

Fog appears likely again tonight but may not be that dense as
upstream mid clouds and potential showers encroach over the
mountains.

Expect VFR through 18z Sunday. Sunday should have more coverage
of storms after 18z.

.EXTENDED AVIATION OUTLOOK...

The weather pattern will change very little through early next
week, remaining conducive for isolated to scattered afternoon &
evening storms, with higher coverage on some days more than
others. Outside of storms, expect VFR conditions but with the
potential for locally dense fog and MVFR/IFR stratus developing
overnight, especially for locations that received significant
rainfall during the evening prior.

&&

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

&&

$$

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