478
FXUS61 KRNK 011325
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
925 AM EDT Tue Jul 1 2025

.SYNOPSIS...
A cold front will move through the region late today, bringing
storms capable of producing damaging winds and torrential rain.
A slightly cooler and less humid airmass moves into the region
by Thursday, with a warm but pleasant holiday weekend in store
for most of the area with little to no rainfall expected. By
early next week, the typical summertime daily afternoon
thunderstorm pattern returns.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 900 AM EDT Tuesday...

Key Message:

1) Numerous to widespread coverage of storms this afternoon and
evening. Some will be strong to severe with wind and torrential
rains the main threats.

Water-vapor imagery this morning indicates an upper trough
moving east across the Great Lakes/lower OH Valley. This feature
will cross the Appalachians by mid-late evening...preceded by an
abundance of moisture and dynamic lift. In the low levels, a
cold front analyzed over the southern Great Lakes into the lower
OH Valley/Mid South will gradually progress east/southeast
crossing our forecast area this evening.

Convective allowing models showing storms firing up along the
Blue Ridge by noon today, before the pre-frontal, then frontal
convection increases coverage through the afternoon/evening.

Best shear will stay north of us but dewpoints in the upper 60s
to lower 70s combined with the heating from the sunshine and
good low level convergence will fuel storms, with damaging winds
and potential for excessive rainfall the main threats. Cannot
rule out some hail but environment is not as conducive for hail.

The front enters the mountains by sunset, then slows as it
shifts to piedmont later tonight. Although not everyone will see
rain, most will so kept probability`s in the 60 to 90 percent
rain. With pwats running 1.75+", storms will be efficient rain
producers and storms could train over the same area in waves, so
localized flash flooding is not out of the realm. Will have to
monitor but given isolated threat will not have a flood watch.

There will be some slight hint of airmass change in the
mountains by dawn Wednesday but not much, dewpoints dropping
into the lower to mid 60s as opposed to upper 60s to lower 70s.

Coverage for showers/storms will become more widely scattered
late tonight with best coverage with the front in the Piedmont.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
As of 100 AM EDT Tuesday...

Key Points:

1. Continuation of showers/storms on Wednesday, especially in the
east.
2. Dry Thursday and Friday.
3. Above normal temperatures all three days.

A look at the 30 Jun 12Z NCEP Ensemble Mean 500mb Geopotential
Heights shows a shortwave trough situated along the mid-Atlantic
east coast of the US Wednesday morning. Another shortwave trough
will be on the heels of this first one, positioned over Hudson Bay.
A generous area of upper level ridging will extend from the Rockies
the Gulf Coast states and across FL. A low/trough combo will extend
from the Gulf of Alaska to the Pacific Northwest. On Thursday, the
second shortwave trough crosses our region during the morning hours.
Ridging continues over the same general as on Wednesday. Likewise,
the low/trough combo remains across far western CONUS. For Friday,
the trough over the mid-Atlantic area on Thursday is expected to now
be centered over the Canadian Maritimes. The ridge axis shifts east
the the Mississippi Valley to FL. The far western CONUS trough
becomes a little less amplified.

At the surface, on Wednesday morning, a cold front will extend from
the Canadian Maritimes southwest through New England to over far
eastern VA/NC. High pressure will be centered over the mid-
Mississippi River Valley, and ridge axis will be positioned west-
east over FL. On Thursday, the center of high pressure makes
progress eastward, reaching the Lower Ohio Valley by the morning
hours. A lee trough is expected to develop over the western High
Plains to the western Central Plains states. On Friday, high
pressure will be centered over PA/NY during the morning hours with
its ridge axis extending to the SE US. To the west, a trough will be
located from the Northern Plains States to the Central Plains
states.

A look at the 30 Jun 12Z NAEFS Ensemble Situational Awareness data
shows 850mb temperatures around +17C through the period.

The above weather patterns offer the following forecast. With an
upper shortwave trough across the area on Wednesday combined with
daytime heating, we are expected showers and storms to develop,
especially over eastern portions of the region. As the upper
shortwave trough exits to the east, the coverage will also decrease
from west to east after sunset.

For Thursday and Friday, with a building area of high pressure over
the region, no showers/storms are forecast.

Through the period, temperatures will average three to five degrees
above average.

Confidence in the above weather scenario is high.

&&

.LONG TERM /SATURDAY THROUGH MONDAY/...
As of 100 AM EDT Tuesday...

Key Points:

1. Dry still for Saturday.
2. Progressively greater potential for showers/storms Sunday into
Monday.
3. Temperatures above normal all three days.

A look a the 30 Jun 12Z NCEP Ensemble Mean 500mb Geopotential
Heights shows a ridge axis extending from the Great Lakes to Florida
on Saturday. A shortwave trough is expected to be over the Central
Plains states while a broader trough remains parked over far western
CONUS. On Sunday, ridging remains over our region. The Central
Plains shortwave trough advances toward the Great Lakes region. The
far western CONUS trough amplifies. On Monday, little change is
expected in the overall synoptic pattern as compared to Sunday.

At the surface, the center of surface high pressure shifts east to
off the NJ coast. A front/trough will extend from Hudson Bay to the
Central Plains states. On Sunday, ensemble averaging removes any
specific location of the center of the surface high. However, a ridge
axis is expected to be situated from the western Atlantic to over
the Carolinas and into the Tennessee Valley. A baroclinic zone will
extend from southern Quebec to the Central Plains. On Monday, the
ridge axis weakens and shifts a bit into the western Atlantic. The
baroclinic zone edges closer to the Ohio Valley.

A look at the 30 Jun 12Z NAEFS Ensemble Situational Awareness data
shows 850mb temperatures around +19C through the period.

The above weather patterns offers the following forecast.

High pressure will slowly lose its influence over the region as its
center slowly progresses eastward. Concurrently, a front will make
gradually headway southeast towards the region. While Saturday still
looks like a dry day for the region, progressively Sunday into
Monday, the coverage of diurnal showers/storms will increase across
the area. Temperatures will average five to eight degrees above
normal each day.

Confidence in the above weather scenario is moderate to high.

&&

.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
As of 915 AM EDT Tuesday...

Unsettled weather likely this afternoon and evening as a cold
front crosses the the region preceded and accompanied by
numerous to widespread showers and thunderstorms.

Showers and storms will likely impact most if not all taf sites
during the afternoon, leading to sub-VFR flight conditions at
times. High-res models indicate storms will fire along the Blue
Ridge first, from TNB-HLX, and along the Appalachian Divide
from MKJ-BLF to just NW LWB. Have VCTS for most sites by 16-20z
time frame then enough coverage of storms to have moderate TSRA
in at all TAF sites in the late afternoon/early evening 20-01z
time frame.

Some storms could produce gusty winds of 20-25+ knots but most
of the time winds will be southwest to west under 10kts.
Showers/storms will be decreasing overnight with potential for
IFR to LIFR cigs with MVFR to IFR vsbys. Confidence is low on
how low cigs will go but higher confidence on sub-VFR conditions
after midnight local time.


EXTENDED AVIATION OUTLOOK...

Passage of a cold front will bring bring drier conditions back
to the region for Wednesday and Thursday. VFR conditions are
expected outside of morning valley fog Wednesday through next
weekend, with only isolated chances for showers and
thunderstorms expected late in the week.

&&

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

&&

$$

SYNOPSIS...WP
NEAR TERM...PM/WP
SHORT TERM...DS
LONG TERM...DS
AVIATION...JCB/PM/WP