Marshall, Virginia Weather Forecast Discussion

528
FXUS61 KLWX 210617
AFDLWX
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
217 AM EDT Sun Sep 21 2025
.SYNOPSIS...
Wedging high pressure remains over the area today with increased
onshore flow yielding cooler temperatures and cloudy conditions. A
warm front will lift north through the area tonight into Monday
bringing warmer temperatures and scattered thunderstorm chances to
the mountains. Meanwhile, high pressure will continue offshore
Tuesday allowing a cold front and cutoff low pressure system to move
toward the region. Beneficial precipitation chances will accompany
the front with several pieces of energy rolling along it Wednesday
into the start of the upcoming weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
Current radar as of 215am continues to show an area of showers and a
few embedded t-storms working across the southern Shenandaoh Valley
into the central VA Piedmont. This activity is in association with a
remnant shortwave disturbance which dumped one to three inches
of rain across portions of the Allegheny Highlands yesterday
and one to two and half inches of rain across portions of Nelson
and Albemarle counties this morning. This activity will
continue east along the I- 64 corridor this morning before
diminishing prior to sunrise.
1028-1030mb high pressure will drift across the Gulf of Maine toward
the Canadian Maritimes today while remaining wedged along the
eastern face of the Appalachians. Meanwhile, the associated
stalled boundary to the south will wash out over central and
southern portions of Virginia before retreating back to the
north as a warm front tonight into Monday morning. Onshore flow
will ensue prior to the warm frontal passage yielding cooler
temperatures and increased low/ mid level cloudiness across the
region. Some patchy drizzle and light shower activity also
cannot be ruled out, especially across the Shenandaoh Valley and
Alleghenies early this morning due to the proximity of the
dissipating front and residual shortwave passing through. Highs
today will range from the low to mid 70s across the mountains
and northeast/central MD to upper 70s across central VA. The
stratus looks to hold steady across most of the area through
mid- afternoon likely eroding across central/eastern VA and
central/eastern MD later this afternoon and evening as a warm
front lifts northward into the region.
The warm front continues to lift north tonight into early Monday
while surface high pressure shifts further off the northern New
England coast. As a result, expect the wedge to continue to erode as
southerly return flow takes over yielding warmer temperatures and
increased moisture across the region for the start of the new
work/school week. Lows tonight will fall back into the mid to upper
50s and low 60s. Some fog cannot be ruled out especially in the
river valleys and in areas that see substantial clearing.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Wedging high pressure will continue to weaken Monday into Tuesday as
it pushes further offshore. Meanwhile, a warm frontal boundary will
lift through the region Monday morning with a cold front and cutoff
low pressure system set to approach from the Great Plains region
Tuesday into midweek. The cutoff low pressure system and it`s
associated front will be slow to move across the area with the bulk
of any precipitation at least for the early part of the week
remaining west of the Blue Ridge (PoPs 30-50 percent). More
widespread precipitation looks to arrive with the front and several
pieces of energy tracking along it Wednesday into the upcoming
weekend (see Long Term below).
Overall synoptic 500 mb flow will remain westerly with south to
southwesterly winds at the surface. This will allow for a boost in
temperatures and moisture across the region. With that said, expect
PWATS to run abnormally high for this time of year hovering
between 1.1-1.6 inches per latest CAMS/synoptic guidance
(75th-90th percentile). The rich moisture combined with subtle
instability 500- 1500 j/kg of CAPE on both Monday and Tuesday
afternoons will yield fairly efficient downpours out of any
convection that forms. Overall convection appears to be spotty
to scattered and confined to the mountains given the lack any
real surface features (i.e warm front to north) and residual
high pressure to the east. With limited shear under 30 kts and a
lack of steering flow some training will likely occur. Given
the recent drought conditions, rainfall looks to be beneficial.
We`ll have to keep an eye out on portions of the Alleghenies
with some locations in western Pendleton, western Highland,
western Augusta, and western Nelson counties picking up between
1.5-3" of rain Sunday. These areas may run into some drainage or
quick flash flooding issues if storms can train over them.
Areas east of the Blue Ridge will likely remain dry given the
influence of high pressure nearby.
Highs Monday and Tuesday will climb back into the upper 70s and low
to mid 80s (low 70s mountains). Skies will turn partly to
mostly cloudy both days with more sun in the east compared to
western portions of the forecast area. Overnight lows will fall
into the upper 50s and low to mid 60s. Some river/mountain
valley fog is possible during the late night/early morning
hours.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Several pieces of vorticity are expected to consolidate into a
cutoff upper low over the Upper Great Lakes/Mid-Mississippi Valley
on Wednesday, before slowly drifting eastward toward the Ohio and
Tennessee Valleys Thursday through Saturday. Such a pattern will
favor daily chances for showers and thunderstorms, which should
bring beneficial rain to the region. As is often the case with
cutoff upper lows, ensemble spread is large with respect to its
exact positioning this far out. As a result, confidence in the finer
scale details is low. Daytime high temperatures are expected to be
near normal, with primarily mid 70s to near 80. Overnight low
temperatures are expected to be well above normal, with low to mid
60s for most.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
Residual showers and thunderstorms down around KCHO, KCJR, and
KRIC look to diminish in coverage prior to 12z/8am. This
activity is in association with a piece of energy passing south
of the region. Outside of the shower and t-storm activity south
of the corridor sub-VFR conditions prevail due in part to
onshore easterly flow from wedging high pressure north of the
region. This has led to increased MVFR to even pockets of IFR
stratus across most of the terminals. Low level clouds look to
hang around through at least mid-afternoon with a slow erosion
of the wedge down across central/eastern VA and central/eastern
MD this afternoon. Skies will remain BKN-OVC through the the
valid TAF period although some of the cloud cover will likely
scatter out in eastern and southern zones later this afternoon
into the early evening hours. Hi-res CAMS suggests another round
of stratus and perhaps some fog overnight as a warm front lifts
through the region. Some light showers and drizzle are possible
throughout this morning especially at terminals south of I-
66/US-50 and west of US-15. Overall most terminals will remain
dry with CIGS being the main concern for aviation.
VFR conditions return Monday into Tuesday as a warm front lifts
north of the region and high pressure pushes offshore. A shower or
thunderstorm cannot be ruled out west of a line from KHGR/KMRB to
KCHO as the warm front lifts north and several pieces of energy pass
to the north and west of the region. This may lead to temporary sub-
VFR reductions on Monday and Tuesday afternoons. The front combined
with high pressure moving offshore will shift the winds from the
east on Sunday back to the south and southwest Monday into Tuesday.
Expect gusts between 10 to 15 kts mainly during the afternoon and
evening hours (especially at terminals near the waters and along the
ridges).
Prevailing VFR conditions and south to southeasterly winds are
expected on Wednesday and Thursday. Higher chances of showers and
thunderstorms are possible at all terminals during the mid and late
week period as a slow moving front and multiple waves of low
pressure push through.
&&
.MARINE...
One or two SCA level gusts have been observed across the middle and
open waters of the bay this morning due in part to elevated easterly
flow. This is due in part to a tightened pressure gradient
between wedging high pressure to the north and a dissipating
shortwave/front (to the south) that will lift north as a warm
front late tonight into Monday. For now, looking to handle any
brief windows of SCA gusts this morning with Marine Weather
Statements. High pressure shifts offshore Monday while the warm
front lifts north of the waters. This will lead to southerly
channeling and an additional period of SCA conditions Monday
night into Tuesday morning.
There is a chance of showers and thunderstorms across the waters on
Tuesday and especially Wednesday into Thursday with a cold front
nearby. Winds remain out of the south Tuesday at sub-SCA levels. Sub-
SCA level south to southeasterly winds are expected on Wednesday and
Thursday.
&&
.TIDES/COASTAL FLOODING...
Tide levels increase today as onshore easterly flow raises
anomalies. Additional increases are possible Monday as high pressure
pushes offshore and southerly winds return bringing more water
northward. In turn, this may result in action stage at several sites
and minor tidal flooding at the more sensitive locales (i.e
Annapolis).
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...None.
&&
$$
SYNOPSIS...EST
NEAR TERM...EST
SHORT TERM...EST
LONG TERM...KJP
AVIATION...KJP/EST
MARINE...KJP/EST
TIDES/COASTAL FLOODING...LWX

NWS LWX Office Area Forecast Discussion