574
FXUS61 KRNK 310803
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
303 AM EST Fri Jan 31 2025

.SYNOPSIS...
A warm front lifts north through the area this morning, followed
by a cold front this afternoon. Expect periods of rain this
morning, followed by a line of showers this afternoon. High
pressure works across the Great Lakes into New England this
weekend keeping the weather mainly dry, but clouds will stick
around due to the wedging high pressure.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 220 AM EST Friday...

Key Messages:

1) Excessive Rainfall over the Greenbrier Valley into portions of
the Alleghanys possible through late afternoon. No changes to
current Flood Watch.

2) Gusty southwest winds will bring mild temperatures to the Piedmont
today.

Isentropic lift is being maximized this morning from eastern KY into
Virginia along the US 460 corridor as evidenced by radar returns of
35-45dbz, some of this is bright banding due to freezing level
around 8-9kft but still some pockets of moderate/heavy rain.
However, hourly rates are mainly under 1/2".

High-resolution models are close but some differences in location of
heavier rains could impact flood potential. Leaning toward a blend
appears best as 00z 4km NAM is handling current conditions better,
but expect a shift north over the next few hours to put axis of
better rainfall toward the I-64 corridor. Still looks like the
Greenbrier Valley has the higher potential for seeing flooding from
snowpack upstream, and also the mountains over western Greenbrier
could have flooding concerns, as remote sensing suggests 2-4 inches
of snow water equivalent still in place here. Given all that, no
changes to the watch planned.

The isentropic lift in the 295-305K range looks to move out between
12-18z, so a lull in rainfall may occur before the showers with the
cold front move into the are from west to east by late morning into
the afternoon. Cannot rule out some rumbles of thunder over toward
far SW Va into the NC mountains, but given clouds and rain, not
seeing a lot of instability to suggest having thunder in the
forecast.

Showers will exit west to east this evening with lingering upslope
rain showers over the mountains lasting til Sat morning. A few
snowflakes could mix in across the mountains of WV but overall, not
expecting much.

All told, rainfall totals from this event, will range from 1-2"
along north of US 460 from Richlands to Blacksburg to Lynchburg,
maxing out over 2" over the Greenbrier mountains/valley and portions
of Summers and Mercer county, WV, to a half inch or less along/south
of the VA/NC border.

A southwest low level jet also works into the Piedmont this
afternoon ahead of the front around 50-60kts. Clouds again may limit
mixing, but still enough for gusts to 30 mph there. Winds behind the
cold front tonight may gust to 25-35 mph in the higher ridges, but
not a lot of cold advection and low level jet is weaker, so most
will only experience gusts to 20-25 mph.

Highs today will range from the upper 60s from Danville/South
Boston, VA into the NC Piedmont, to around 60 Roanoke/Lynchburg/Mt
Airy, to lower to mid 50s in the mountains.

Lows tonight are going to be in the mid to upper 30s in the
mountains, to lower 40s east.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
As of 230 AM EST Friday...

Key Messages:

1) Relatively quiet forecast period.

2) Above normal temperatures for early next week.

A relatively quiet forecast period going into February. There may be
some residual rain showers on Saturday morning, but this will
cease by Saturday afternoon. A surface high pressure system to
our north will move eastward and start to briefly wedge itself
into the area on Sunday before heading out into the ocean. A
low pressure system along a similar latitude as the high will
follow it but will unlikely have any impact to our region.
Afterwards, a strong high pressure system follows and takes
shape over the Great Plains.

During the weekend, a low level jet will quickly propagate northeast
between the northern low and a high off the coast of southeastern
United States. This jet is strong enough to provide a brief period
of gusty winds, particularly along and west of the Blue Ridge. The
impact of this jet is highly dependent on its trajectory so
other parts of the region could be affected if this jet moves
more to the east or south. Sustained winds of 10-15 kts as well
as gusts of 15-20 kts are possible as this jet zips through.

The alignment of the northern low and high pressure system will
provide southerly winds for most of the forecast period. This,
combined with quasi-zonal 500mb winds, will result in veering of
winds and warm air advection. High temperatures will be in the
40s mountains to 50s Piedmont Saturday, but could be cooler with
the wedge Sunday, with 40s for most except 50s far SW VA and NC.
Warmer Monday with upper 50s to upper 60s west to east. Lows
will generally be in the 30s and 40s with some elevated areas
having lows in the upper 20s.

&&

.LONG TERM /TUESDAY THROUGH THURSDAY/...
As of 200 AM EST Friday...

Key Messages:

1) Temperatures 10 to 15 degrees above normal through Thursday.

2) Precipitation chances increase Wednesday and Thursday for
the area.

A cold front will be crossing the area from the north through
Tuesday morning, and stalls around the VA/NC state line, but not
expected to bring any precipitation to the area. High pressure
builds over the northeastern US, and will expand southward, wedging
along the eastern side of the mountains. A surface low will move
into the Ohio Valley Wednesday, and then tracks north into the Great
Lakes region by Thursday. The stalled front will then retreat
northward across the forecast area as a warm front by Thursday as
the wedge starts to erode. Long range deterministic models still
show differences in where the heaviest precipitation sets up, so
forecast uncertainty increases after the middle of the work week.

Another cold front will approach the area from the west on Thursday,
and track through the Mid Atlantic by Friday, which will bring
another round of precipitation to the area. Southwesterly winds will
increase and become gusty on Thursday ahead of the front as the
pressure gradient tightens between the high moving east and the low
associated with the cold front moving into the Midwest.

Ridging aloft over the southeastern US will keep temperatures on a
warming trend through the period, with high temperatures between 10
and 15 degrees warmer than normal Tuesday and Wednesday, in the mid
50s to low 60s in the east on Tuesday, and mid to upper 50s areawide
on Wednesday, with the wedge in place. Thursday looks to be even
warmer, as southwesterly flow increases ahead of the approaching
cold front. Highs on Thursday will be up to 20 degrees warmer than
normal, in the mid to upper 60s. Lows will also be mild, in the mid
40s for most through the period, increasing to near 50 for the NC
Piedmont by Thursday morning. With all that said, confidence is high
that the precipitation through the second half of the week will be
rain.

&&

.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
As of 1234 AM EST Friday...

Expect sub-VFR cigs/vsbys with moderate rain to impact terminals
along/north of BLF-BCB-ROA-LYH line this morning with little to
no rain or sub-VFR at DAN. There will likely be a lull as the
warm front lifts through in the rain and cigs/vsbys may improve
to VFR before more rain with the cold front arrives in the
afternoon, with cigs/vsbys at least in the mountains dropping to
MVFR, possibly IFR at BLF/LWB.

Should see rain move out by 06z/Sat with improving cigs/vsbys.

Winds are going to be light over most of the area this morning
while a strong low level jet out of the south-southwest brings
some low level wind shear to portions of the mountains. BLF
could stay gusty through through the period, with south to east
winds become southwest to west late morning into the afternoon.

The rain could be heavy at times at BLF/LWB.

Confidence in the above scenario is above average for sub-VFR
but moderate on how low cigs/vsbys drop in the rain.

EXTENDED AVIATION OUTLOOK...

Clouds scatter out for areas along and east of the Blue Ridge
Friday night into Saturday morning. The mountains will take
longer to improve with low clouds hanging on and perhaps some
light upslope showers. Winds will be gusty Friday night into
Saturday behind the front.

Sunday and Monday look VFR with southerly winds Sunday turning
westerly on Monday. A weak frontal passage Tuesday may bring
northerly winds and some rain to the mountains along with sub-
VFR conditions.

&&

.HYDROLOGY...
As of 245 AM EST Friday...

About 2 to 4 inches of snow water equivalent is locked up in
the WV mountains, mainly from western Greenbrier northward.
This along with runoff on frozen ground is expected to
contribute to the amount of water going into area rivers and
streams. QPF amounts from rainfall should range from 1 to 2
inches north of US 460, with the highest along/north of I-64 in
Greenbrier County.  As a result, we could see some river
flooding, especially in the Greenbrier basins. Localized urban
flooding will be possible if rates are higher than a half inch
per hour. A Flood Watch remains in place for SE WV into portions
of the Alleghanys to upper Clinch Valley through Friday night.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...Flood Watch through Saturday morning for VAZ007-010-011-
     018>020.
NC...None.
WV...Flood Watch through Saturday morning for WVZ042>044-507-508.

&&

$$

SYNOPSIS...WP
NEAR TERM...WP
SHORT TERM...CG
LONG TERM...AS
AVIATION...BMG/SH/WP
HYDROLOGY...SH/WP