031
FXUS61 KRNK 091756
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
156 PM EDT Sun Mar 9 2025

.SYNOPSIS...
A storm system passing to our south may bring some clouds to the
area through Sunday, otherwise high pressure will keep conditions
dry for the upcoming work week. Temperatures warm up significantly
next week starting Tuesday.

&&

.NEAR TERM /THROUGH MONDAY/...
As of 200 PM EDT Sunday...

Key Messages:

1) Cloud cover at times but warm again tomorrow.

An open upper level wave of low pressure currently over TX
gradually makes its way due east through Monday. The system
will close off and pass to our south, and will continue to
spread some light moisture into the area. Expect mostly cirrus
as well as altostratus, with a low chance for a shower over our
northwestern NC counties during the day and afternoon Monday.
PWATs increase to around 0.4 inches over a narrow area south of
a line from Mount Airy, NC to South Boston, VA, and there will
be synoptic scale forcing in place. Even if it does rain, QPF
will be a couple hundredths of an inch at most. More likely we
will see virga or a few sprinkles. Also, not expecting enough
precipitation in order to wet bulb temperatures down far enough
to produce freezing rain. Clouds and precipitation chances end
as the trough axis moves east in the afternoon.

Low temperatures will be in the low to mid 30s for the
mountains, and the upper 30s to low 40s by morning. High
temperatures will be similar to today for the piedmont, but a
few degrees warmer in the mountains, with mid 50s to low 60s
across the area.

Confidence in the near term forecast is high.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 100 PM EST Sunday...

Key Points:

1. Above normal temperatures.
2. Small chance of showers on Thursday, otherwise dry.

A look at the 9 Mar 00Z NCEP Ensemble Mean 500mb Geopotential
Heights shows a closed low centered over SC on Monday evening. A
second closed low is expected to be offshore of southern CA.
Broad ridging will be centered over the Central Plains states. A
deep closed low is expected to be over James Bay with an
associated shortwave trough progressing into western Ontario. By
Tuesday evening, the low off the Pacific Coast is expected to
have progressed to over CA/AZ as an open wave. Nearly zonal flow
will extend from the Central Plains to the mid-Atlantic region,
and little change in position is expected for the James Bay
low, but its associated shortwave trough will be heading through
Quebec. By Wednesday evening, flow aloft across our region
backs southwest in advance of an approaching shortwave trough
over the Central and Southern Plains states. Little change is
expected with the James Bay low, other than the associated
shortwave trough heading east over the Canadian Maritimes. A
strongly amplified trough will be approaching the Pacific Coast.

At the surface, a low pressure center is expected to be off the SC
coast early Monday evening. Concurrently, another low is
expected to be near MN/WI. A weak ridge of high pressure will
be between the two, extending from TX/LA, northeast to over the
mid-Atlantic region. By Tuesday evening, the center of the
surface high shifts east, closer to FL, with its ridge axis
extending north along the spine of the Appalachians.
Concurrently, the low off the SC move farther east into the
Atlantic. The MN/WI low heads slowly east into the Great Lakes
region. By Wednesday evening, the Great Lakes low is expected to
have moved east and be over New England. Its associated cold
front will be near or approaching the area by then, potentially
stalling over the area as a backdoor cold front Wednesday night
into early Thursday as the parent low outraces the front.

A look at the 9 Mar 00Z NAEFS Ensemble Situational Awareness data
shows 850mb temperatures around +6C Monday evening. Values hold
nearly steady through Monday night. On Tuesday, values increase to
around +8C to +10C, n-s, across the region. A small decline to +5C
to +8C is expected Tuesday night. On Wednesday, look for a small
increase to +6C to +9C, ne-sw. Little change is expected Wednesday
night.

The above weather patterns offer the following forecast. Mild
weather is expected Tuesday into Wednesday thanks to the
presence of high pressure which will cross our region, and
then take up residency off the East Coast. This pattern
transition will allow for increasing warm air advection into the
region. On Wednesday night, the existence of a backdoor cold
front and the approach of a shortwave trough may allow for a
small amount of coverage of showers, but confidence is not high.

Confidence in the above weather scenario is moderate to high.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 100 PM EST Sunday...

Key Points:

1. Temperatures continue well above normal.
2. Strong cold front passage expected this weekend. Current
timing offers at Saturday night into Sunday timeframe, but the
system may trend slower.

A look at the 9 Mar 00Z NCEP Ensemble Mean 500mb Geopotential
Heights shows a shortwave trough across the mid-Atlantic and
Southeast US on Thursday. A longwave trough deepens over western
CONUS. An upper low remains anchored over James Bay. By Friday
evening, an upper level ridge develops over the East Coast
region in response to a deepening longwave trough, and perhaps
with a closed central low pressure system, over central CONUS.
By Saturday evening, the eastward progression of the central
CONUS longwave stalls a bit as an upper ridge builds even
stronger just off the Atlantic coast. Southwest flow aloft
increases significantly over our region in repsonse to both
systems. On Sunday, the approaching longwave trough becomes
slightly negatively tilted with its axis reaching a line roughly
from the Great Lakes region to the Southeast US.

At the surface, any stalled front over the region will be
replaced through the day and into the night Thursday with
increasing southerly flow in advance of a strengthening low
pressure system in the lee of the Rockies. For Friday into
Friday night, the same low pressure continues to deepen, head
east, and be centered over eastern NE by the early evening. S-SW
flow over our region increases with a warm front over or just
north of the area. For Saturday into Saturday night, the surface
low is expected to head to WI/MI by the early evening with an
associated cold front extending south through the Mississippi
Valley. Strong S-SW continues over our area along with rising
heights. By Sunday evening, the low is expected to be just east
of James Bay with its associated cold front over, or just east
of our region. Heights fall rapidly post frontal passage on an
increasing northwest wind.

A look at the 9 Mar 00Z NAEFS Ensemble Situational Awareness data
shows 850mb temperatures on Thursday and Thursday night will
average around +8C across the area. For Friday, values climb
slightly to around +9C to +10C and remain at similar level
Friday night. For Saturday, expect a small increase to +10C to
+11C, ne-sw. For western portions of the region, these numbers
correspond to values within the 90 to 97.5 percentile of the
30-year CFSR climatology. Saturday night, values decrease to
around +6C to +9C, nw-se by daybreak Sunday. On Sunday, values
continue to fall through the day, reaching +3C to +6C, nw-se by
the early evening.

Looking at the same NAEFS output, but this time for the Mean
Integrated Water Vapor Transport, shows increasing very good
moisture transport of 400 to 500 units (corresponding to the 90
to 97.5 percentile) starting over the region as early as
Saturday morning. These numbers start to exceed 750 units
(97.5 to 99.5 percentile) in the west Saturday evening. This
band of impressive moisture flux progresses west to east across
the area Saturday night. The tail end of this better moisture
advection exits the region west to east Sunday morning.

The above weather patterns offer the following forecast. With
the potential for stalled front over the area, and the passage
of a shortwave trough, there is a small chance for showers for
parts of the area. However, confidence is not high. Temperatures
will be slightly cooler on Thursday thanks to the presence of
the front and at least increased cloud cover. However, values
still will be above normal for this time of year. As we approach
the weekend, look for increasing southerly flow in advance of
an approaching potent cold front. This southerly flow will yield
both increasing temperatures and dew point values. While dry
weather is expected Thursday into Thursday night, on Friday we
may see the beginnings of southerly flow upslope precipitation
developing along and near the crest of the Blue Ridge. This
potential will increase Friday night, and especially on Saturday
when the mean integrated water vapor advection begins
increasing higher than the 90th percentile within the
climatology. The latest ensembles paint a cold frontal passage
Saturday night into Sunday morning. For now, our forecast will
reflect this timing, but we would not be surprised as a get
closer to the weekend, models trend to a slower timing. Also
currently, output from the 9 Mar 13Z run output from DESI using
the NBM-CONUS dataset paints less than a 10 percent probability
of thunder Saturday night into Sunday. If the front does slow
down, perhaps Sunday would become a more likely candidate for
thunder as the passage of the front would coincide better with
peak heating of the day.

Temperatures during this portion of the forecast will remain on
the mild to very mild side for this time of year.

Confidence in the above weather scenario is moderate to high
Tuesday and Wednesday and low/moderate for Thursday and
Friday.

Confidence in the above weather scenario is moderate to high
regarding well above normal temperatures, and low to moderate
regarding timing of the cold front.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
As of 200 PM EDT Sunday...

VFR conditions expected through the 24 hour valid TAFs. High
clouds will be present, but not expecting much below 8-10kft. A
storm system will pass south of the region Monday. Clouds may
thicken but remain VFR. Virga may be present, but any surface
based precipitation is expected to remain primarily south of
I-40. The storm will move off the southeast Atlantic Coast
Monday night. Winds will be near calm tonight, and light
northerly Monday as low pressure passes to our south.


.EXTENDED AVIATION OUTLOOK...
In general our forecast area will remain VFR through Wednesday
with high pressure in control. There is some chance for light
rain or drizzle and sub-VFR conditions for the mountains
Wednesday night into Thursday associated with a backdoor front
that may come into the area from the northeast.

&&

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

&&

$$

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