Tiptop Virginia Weather Forecast Discussion

589
FXUS61 KRNK 070607
AFDRNK
Area Forecast Discussion
National Weather Service Blacksburg VA
207 AM EDT Tue Oct 7 2025
.SYNOPSIS...
High pressure shifts offshore today while a cold front
approaches from the west. Showers and thunderstorms will begin
this afternoon in the mountains, and spread southeast tonight
into Wednesday. Noticeably cooler temperatures are expected
Thursday through the weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 200 AM EDT Tuesday...
Key Message:
1) Increasing clouds today, showers and isolated storms
beginning this afternoon as a front moves south.
High pressure over the Carolinas will be squashed to the south
by a significant mean trough moving into the eastern CONUS.
This will help drive a cold front towards the Blue Ridge today
and tonight. Showers and isolated thunderstorms are possible
beginning this afternoon ahead of the front, with marginal
instability and shear. This should be a beneficial and wide-
reaching rainfall which will continue into Wednesday as the
boundary shifts south. There is a 70% chance or better of a
quarter inch of rain for areas along and west of the Blue Ridge
by Wednesday morning.
Apart from patchy fog and stratus this morning, look for
increasing cloud cover which will remain throughout the next
48 hours at least. There is a 75% chance for highs to remain
below 75F in the mountains, and a 100% chance for highs to
remain below 80F in the Piedmont today. Tonight, lows should
remain 59F or above due to cloud cover, with a 70% to 100%
chance of that occurring in the mountains and Piedmont,
respectively.
Confidence in the near term is high for most parameters but
moderate for rainfall timing.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
As of 100 AM EDT Tuesday...
Key Points:
1. Mild with showers and a few storms on Wednesday.
2. Cooler and drier Thursday and Friday.
3. Patchy frost possible in the mountains, especially Thursday
night.
A look at the 6 Oct 00Z NCEP Ensemble Mean 500mb Geopotential
Heights shows for Wednesday/Wednesday night a trough extending
from Quebec south to NJ, closed low just off the coast of the
Pacific Northwest, and a ridge axis extending from TX to the
Dakotas. For Thursday/Thursday night, low pressure deepens off
the coast of the Pacific Northwest. A ridge holds fast over much
of the south-central portion of CONUS. A shortwave trough
skirts the US/Canadian border near the Upper Mississippi Valley.
Another weak shortwave trough is expected to over the Lower
Ohio Valley. For Friday/Friday night, the shortwave trough over
the Lower Ohio Valley starts to amplify to over parts of the
Carolinas. Low pressure starts to move onshore the Pacific
Northwest. A high pressure ridge remains nearly stationary over
much of south-central CONUS, and a shortwave trough moves east
across the Great Lakes region.
At the surface, for Wednesday/Wednesday night a cold front will
exit the region by the afternoon and be off the coast of the
Carolinas by the evening hours, curving southwest into Gulf
Coast states. High pressure will be situated over the Great
Lakes region and be entering into the region overnight. For
Thursday/Thursday night, the center of the high is expected to
shift east to over New England, with its ridge axis extending
southwest to along the lee of the Appalachians. For
Friday/Friday night, the center of the high continues
progressing eastward into the western Atlantic by the evening
hours. However, its ridge axis is expected to remain covering
much of the mid-Atlantic and Ohio Valleys. An inverted trough
may begin to develop off the coast of the Carolinas.
A look at the 6 Oct 12Z NAEFS Ensemble Situational Awareness
data shows 850mb temperatures are expected to range from
roughly +10C to +12C, n-s, across the region on Wednesday. For
Thursday, values decrease to roughly +6C to +8C, ne-sw. On
Friday, values may increase a tad to +7C to +9C, ne-sw.
The above weather patterns offers the following forecast. As a
cold front crosses and exits the region on Wednesday, expect
shower coincident to and advance of the front. The best coverage
will be over the southeastern sections of the area. Northwest
portions may be rain-free during the entire day depending on how
far southeast into the region the front will have progressed
before daybreak Wednesday.With heating of the day will come
better organized convection with the potential for some isolated
thunderstorms. High pressure will start to build in quickly
behind the exiting front bringing dry weather and cooler
temperatures to the region Thursday into Friday. Some of the
higher peaks and valley across the mountains may see a touch of
frost Wednesday night, Thursday night, and Friday night with the
best coverage on Thursday night.
Confidence in the above weather scenario is moderate to high.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
As of 100 AM EDT Tuesday...
Key Points:
1. Trending milder.
2. Increased moisture levels/cloud cover.
3. Precipitation chances minimal with the best chances remaining
east of the region.
A look a the 6 Oct 00Z NCEP Ensemble Mean 500mb Geopotential
Heights shows for Saturday/Saturday night, low pressure over
the Pacific Northwest opens up into a highly amplified longwave
trough which covers much of western CONUS. Troughiness over
eastern CONUS broadens in coverage. A ridge over south-central
CONUS is weakened by the expanding western CONUS trough. For
Sunday/Sunday night, the troughiness over eastern CONUS deepens
enough for a closed low to be located near the VA/NC/SC coast
Sunday evening. The northern sections of the western CONUS
trough begins to make progress eastward, with the base of the
trough remaining nearly stationary across CA. The ridge over
south-central CONUS continues to weaken as the western trough
becomes positively tilted. For Monday, More eastward progression
is expected for the western trough, such that a shortwave
separate from the main trough may develop near the Dakotas.
Troughiness continues over eastern CONUS with the closed low
potentially filling and lifting northeast. Weak ridging remains
over south-central CONUS.
At the surface, for Saturday/Saturday night, more development is
expected regarding the inverted trough off the coast of the
Carolinas. Its strengthening helps to shift the ridge axis a
little farther west. Low pressure is expected to develop over
the Upper Plains states with an associated cold front extending
south to along the lee of the Rockies. For Sunday/Sunday night,
an inverted trough is still depicting in the model averaging off
the coast of the Carolinas. High pressure is expected to become
centered over ME with a ridge axis extending southwest along
the Appalachians. Low pressure and its associated cold front are
expected to make headway eastward across central CONUS. On
Monday, Little change is expected regarding the ridge/trough
positioning over and just offshore eastern CONUS.
A look at the 6 Oct 12Z NAEFS Ensemble Situational Awareness
data shows 850mb temperatures on Saturday and Sunday are
expected to be around +10C. On Monday, values increase a little
to around +11C.
The above weather patterns offers the following forecast. A
ridge of high pressure will generally over, or just west of,
the region through this portion of the forecast. Additionally, a
trough/low is expected to be heading north off the southeast US
coast to off the mid-Atlantic coast. Cyclonic flow around this
feature, and anticyclonic flow around the ridge, will combine to
provide an onshore flow into our region. This will allow for
milder temperatures and increasing moisture levels. The result
should be at least a trend of increasing temperatures and daily
cloud cover. What is not as confident is the extent any
associated precipitation will reach parts of the area. The
latest trends are for less precipitation than suggested this
time twenty-four hours ago with the bulk of any precipitation
remaining closer to the coast.
Confidence in the above weather scenario is moderate regarding
temperature trends and low regarding the question of any
precipitation impacting parts of the area.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
As of 230 AM EDT Tuesday...
An area of stratus covered much of the area, with BLF and LWB
currently in the clearer areas. Low VFR/high MVFR dominates,
with ceilings on the edge for much of today. A cold front
approaching will introduce SHRA and isolated TSRA into the
region beginning this afternoon in the mountains, and spreading
southeast tonight into Wednesday. Ceilings will lower in -RA and
stratus, especially after 08/00Z, and again after 08/06Z as the
front moves south. Some lower visbys are also possible.
Winds look to remain predominantly southerly to southwesterly
on today at around 5-10 knots, with gusts up to 20 knots at
times during the afternoon and evening. Winds weaken after
08/00Z.
EXTENDED AVIATION OUTLOOK...
Shower activity looks to linger across the area into Wednesday,
with clearing conditions and VFR developing by late Wednesday
into Thursday morning. Gusty NNW winds are expected beginning
late morning Wednesday behind the front; expecting 20 kts
through Wednesday night, and up to 15 kts and veering to the
ENE Thursday.
VFR conditions are forecast to continue through the end of the
workweek and beginning of the weekend.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...BMG/SH
NEAR TERM...SH
SHORT TERM...DS
LONG TERM...DS
AVIATION...SH

NWS RNK Office Area Forecast Discussion