Harrisonburg, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

954
FXUS61 KLWX 180229
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
929 PM EST Wed Dec 17 2025

.SYNOPSIS...
High pressure near the Delmarva will continue to pull away from
the East Coast. Milder temperatures and dry conditions are expected
through Thursday. A strong cold front will push through the
region Thursday night. Showers will develop with the frontal
passage, followed by gusty winds and colder temperatures once
again late in the week.

&&

.NEAR TERM /THROUGH THURSDAY/...
High-level clouds continue streaming over the area this evening,
with clouds likely lingering for most of the night. A very
subtle front has moved through most of the area, with light
north/northwest winds noted in the surface obs. No additional
changes expected to the forecast for tonight as chilly overnight
lows settle in the mid 20s to low 30s.

Behind the front, a second area of high pressure will build in
through Thursday morning. Temperatures tonight will be a few
degrees milder and closer to average for mid- December.

The second high pressure will move east by midday Thursday to
make room for a developing warm front across southern Virginia
and north-central North Carolina to push northward midday
Thursday through Thursday evening. During the same time that
this warm front is pushing north, a potent upper-level low
pressure system will be shoving eastward across the lower Great
Lakes and Ohio Valley. Additional warmth and moisture will also
be streaming northward ahead of the main low pressure system
and just behind the advancing warm front. Some pre-warm frontal
rain showers are possible Thursday afternoon, but most likely
showers would be more prone to develop behind the warm front and
ahead of the approaching affiliated cold front Thursday evening.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
During the late Thursday evening and overnight into early
Friday morning, showers are expected to develop ahead of a
powerful cold front. This will then be followed by a line of
gusty showers and perhaps a few thunderstorms accompanying the
front itself.

There are a lot of factors at play with this system that still
lend at least some level of concern in terms of a low-end
severe weather threat. First off, there will be plenty of wind
shear to work with. A powerful, negatively-tilted, upper-level
trough will swing through the region early Friday. This will be
accompanied by a 60-70 kt LLJ. Guidance has trended a bit slower
and deeper with this trough over the last few cycles.

In short, deep-layer shear values in excess of 60 knots are
forecast, with impressive curved hodographs yielding low-level
SRH values in the 300-400 m2/s2 range. However, a key component
for severe weather is instability, and this is going to be hard
to come by given the time of day this front rolls through. Low-
level profiles suggest low-topped convection occurring in an
environment with isothermal to moist adiabatic lapse rates in
the lowest several thousand feet, with an inversion around 5-6
kft. Below this inversion, 35-45 kts of wind exists; above it,
50-60 kts. The most likely scenario is that a line of heavy
showers along the actual front will bring some gusty winds down
with it. This seems reasonable given the amount of low-level
winds at play here. However, the magnitude is going to be
greatly hindered by a very steep inversion at the surface until
perhaps right with FROPA. While you can punch some winds
through the inversion given strong enough convection, very
rarely do you get all of that wind down. For that reason, gusts
of 40 to 50 mph seem most likely, with slightly higher not out
of the question, albeit pretty isolated in nature (and perhaps
enhanced over higher terrain).

If there were a spot that is slightly more favored, that would
be across southern MD. As is often the case, this area will see
higher dew points than areas north and west. This would be the
area where the highest thunderstorm threat would be, albeit
still small. It is here that there is some indication of a low-
end tornado threat, but again this will be very conditional on
the fact that some instability is able to develop. A few hi-res
models do have some CAPE in that region, but still thinking it
will just not quite be enough to spin up a tornado. At any rate,
it can`t be completely ruled out, so it is always a good idea
to have a way to get warnings overnight, should we have to issue
any.

Behind the cold front, blustery conditions return for Friday
afternoon in strong northwest winds. Winds could gust 40 to 50
mph for most, especially north of the US-50/I-66 corridor. Wind
gusts of 45 to perhaps 60 mph can be expected over the higher
elevations during this time, with Wind Advisories likely needed
in a future forecast package.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
The long term forecast will be largely dominated by surface high
pressure building over the forecast area. Outside of upslope
precipitation in the Alleghenies, dry conditions are expected across
the forecast area through Monday night. A moisture-starved cold
front tracks across the region on Sunday, bringing cooler
temperatures to start the work week.

On Tuesday, a potent low pressure system tracks across the Great
Lakes into Canada as the associated cold front approaches and tracks
across the forecast area. This will bring a surge of moisture from
the parent low and yield increased precipitation chances. A slight
chance to a chance of precipitation is expected Tuesday afternoon
with conditions drying out overnight.

Temperatures on Saturday will be in the 40s across the area with
overnight lows in the 30s. Temperatures rise into the 40s and 50s
ahead of a cold front on Sunday with overnight lows dropping into
the teens and 20s in the wake of the frontal passage. Temperatures
moderate under high pressure Monday and Tuesday with high
temperatures in the 40s and 50s.

&&

.AVIATION /02Z THURSDAY THROUGH MONDAY/...
High pressure will provide dry and cold conditions through
tonight. Winds become northwest by 22Z, then shift to north and
east overnight at light speeds AOB 5 kts. Beyond that, we can
expect gradual warming temperatures with a southerly wind ahead
of a powerful front set to push through late Thursday. Although
VFR is expected, SREF probs indicate potential fog over the
metros early Thu AM.

Sub-VFR conditions are possible Thursday by late afternoon as a
front approaches the terminals with restrictions likely during
precipitation overnight. Southerly winds gust 15 to 25 knots
Thursday afternoon and into the overnight ahead of the front.
Some convection is possible overnight, but more likely in the
form of a brief heavy downpour, especially along the actual
front early Friday morning. This could also be accompanied by a
surge of 40+ knot winds along the main line.

VFR conditions and gusty winds are expected across all terminals on
Friday in the wake of the cold front, with gusts likely exceeding
30 knots through the afternoon. Winds diminish quickly Friday
evening before becoming light overnight. Southerly winds on
Saturday become light overnight before shifting to northwesterly
on Sunday. VFR conditions are expected both days with winds
gusting 15 to 20 knots each afternoon.

&&

.MARINE...
A very subtle front has moved through the area this evening,
with light northwest to north winds noted over the waters. These
winds shift east by early Thursday morning. Winds will begin to
increase out of the south Thursday afternoon. Small Craft
Advisories are likely beginning by Thursday evening as southerly
winds gust 20 to 30 knots through the overnight ahead of a
powerful cold front.

A brief surge of stronger winds is possible along the cold
front early Friday morning for several hours ahead of the front,
especially in/near heavy showers and perhaps a few thunderstorms.
However, a strong inversion is expected at the surface, which
could help to subdue this threat a bit. Right now, couldn`t rule
out some 40+ knot wind gusts especially along the line early
Friday morning.

Gusty northwest winds will yield high-end Small Craft
Advisories across the waters on Friday at the very least. In
the northern portions of the waters, north of North Beach MD,
winds could reach Gale-force, especially after mid-morning into
Friday evening. As high pressure builds over the area, winds
diminish Friday night, becoming light by Saturday morning.

Small Craft Advisories are possible both Saturday and Sunday
afternoon. Southerly winds on Saturday shift to northwesterly on
Sunday, gusting 15 to 20 knots each afternoon.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Gale Watch from late Thursday night through Friday evening for
     ANZ530>532-535-538>540.
     Gale Watch from late Thursday night through Friday morning for
     ANZ533-534-536-537-541>543.

&&

$$

SYNOPSIS...DHOF/CJL
NEAR TERM...DHOF/CJL/KRR
SHORT TERM...DHOF/CJL
LONG TERM...AVS
AVIATION...AVS/DHOF/CJL
MARINE...AVS/DHOF/CJL/KRR