Mechanicsville, Virginia Weather Forecast Discussion

538
FXUS61 KAKQ 250556
AFDAKQ
AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
156 AM EDT Thu Sep 25 2025
.SYNOPSIS...
High pressure will remain well offshore tonight, with very warm
and more humid conditions through Thursday. A slow moving cold
front moves into the area Thursday night and Friday, with an
upper trough settling over the Southeast by the weekend. This
will bring more unsettled conditions late this week through the
weekend.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
As of 830 PM EDT Wednesday...
Key Messages:
- Earlier tstms have diminished but a chance for showers
  continues overnight, mainly for the NW 1/2 of the CWA.
  Otherwise, warm and humid for late September.
NHC has named Tropical Storm Humberto (the more eastern system
in the central tropical Atlantic) this evening. This if forecast
to slowly drift NW through the weekend, staying well off to our
SE through Monday. Elsewhere, sfc high pressure remains well
offshore of the mid-Atlantic coast, with a WSW flow aloft across
the region in between an upper ridge across the subtropical
western Atlantic, and a broad upper trough stretching from the
Great Lakes down into the Gulf coast states. Had a few strong to
locally severe tstms earlier this evening, with just some
lingering showers now over central and south central VA. Latest
SPC mesoanalysis indicates a lot of CIN with the loss of daytime
heating (and some rain cooled air in the piedmont), though some
minimal ML CAPE and modest shear will allow for additional
showers chances overnight, gradually expected to shift N with
time. The sky will be mostly cloudy across most of the CWA,
except partly cloudy to mostly clear in the SE. Overall, a light
southerly flow should preclude fog development overnight
(though some patchy fog is possible across interior SE VA and NE
NC). Warm and humid (for late September) with lows in the upper
60s to lower 70s.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH FRIDAY NIGHT/...
As of 300 PM EDT Wednesday...
Key Messages:
- The upper height pattern amplifies for the second half of the
  week with a deep trough taking shape over the Mississippi
  River Valley, translating E and NE Thursday into Friday.
The expansive ridge that is set up off the SE coast will remain in
place through late this week. The upper low and associated trough
will gradually advance eastwards over the next few days, with
another upper low developing on the southwestern periphery of this
trough across the Mid-South by Friday. The secondary upper low and
attendant surface front will near our area Thursday and Thursday
night, though the aforementioned ridge will slow the progress of
this system. Thursday will be similar to today in regards to he
environmental set-up and strong daytime heating, but the forcing for
convective initiation will still be further north of our area while
the developing upper low will still be to our southwest. Therefore,
despite PW values 150-180% of normal (1.8 to nearly 2.0"), less
coverage of heavy rain is expected Thursday and Friday as any
convection should be less organized with lesser broad scale lift
locally. With the lessened convective coverage expected Thursday and
the continued southerly flow, temperatures will be able to mid to
upper 80s to near 90 degrees in SE VA/NE NC (low to mid 80s along
the Eastern Shore). Redevelopment along the frontal boundary across
south-central/SE VA and NE NC is expected on Friday through Friday
night. As winds shift to the west then northwest and cloud cover
increases ahead of the approaching front on Friday, temperatures
will not be quite as high as Thursday, with highs forecast to reach
the lower to mid 80s. Lows Friday night will drop into the mid-upper
60s.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 300 PM EDT Wednesday...
Key Messages:
- Unsettled pattern continues this weekend into early next week
  with near seasonal temperatures.
The upper trough lingers across the eastern U.S. with the closed
upper low slowly making its way towards the Mid-Atlantic through
Sunday. This will keep unsettled weather across our area through the
weekend, with increasing chances of showers and isolated
thunderstorms. Well above normal PW values will remain in place this
weekend, so any developing showers may produce heavy rainfall which
will bring much needed rainfall to the area. The upper trough will
remain over the Mid-Atlantic and Southeast into early next week as
high pressure builds down from Canada. Confidence in the forecast
for next week is relatively low due to the complex steering pattern
coupled with the unknowns of the interaction between Humberto
and Al94 . There is increasing confidence in tropical activity in
the western north Atlantic, but consistency between models and
even within individual models has been pretty low. There is a
lot of uncertainty in how the pattern will set up and if there
will be any impacts to the local area. The EPS ensemble has
remained persistent that there will be two tropical systems
(both Humberto and AL94) while the GEFS is only developing
Humberto while AL94 entrains drier air and is overwhelmed by the
other developing system. We will continue to monitor these two
features over the course of the next few days.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
As of 155 AM EDT Thursday...
High pressure is centered offshore as of 06z with low pressure
and a wavy cold front well NW of the region. VFR under BKN-OVC
mid and high clouds inland and SCT closer to the coast. The wind
is light out of the SSW. There is some spotty light rain from
RIC to SBY, but this has had little impact on cigs and vsby.
Primarily VFR through the morning, aside from some brief MVFR
cigs from 10-15z, with the best chc at ECG. Showers/tstms are
expected to develop later this aftn (generally after 20z) and
linger into the evening. There is also a low probability of a
few stronger tstms. PROB30 groups have been maintained for RIC
and SBY, but have not been added for the remaining sites where
probabilities are lower. Some lingering showers are possible
later tonight, with some patchy MVFR cigs possible late tonight
and toward 12z Friday. A SSW wind will increase to 10-15kt later
this morning with occasional gusts to 20kt this aftn, before
diminishing to 5-10kt tonight.
A cold front slowly settles into the region Friday. Showers are
likely with a few tstms possible across SE VA/NE NC Friday
aftn/evening, with showers again likely Saturday. Occasional
sub-VFR conditions are expected. A chc of showers lingers into
Sunday and Monday.
&&
.MARINE...
As of 300 PM EDT Wednesday...
Key Messages:
- S to SSE winds increase later today-early tonight to near 15 kt
with a few gusts to 20 kt likely.
- Another chance of marginal SCA conditions return Thursday into
Friday night primarily for the ocean north of Cape Charles.
- Sub-SCA from Friday through the weekend with unsettled marine
conditions likely from the early to middle part of next week.
Afternoon wx analysis shows high pressure just off the east coast,
with a cold front well to our NW. Winds are S at 10-15 kt with ~3 ft
seas and 1-2 ft waves. The pressure gradient tightens a bit this
evening-early tonight on the back side of the high...which will
result in an increase in wind of a few knots over the marine area.
Wind speeds will average 15 kt during this time with a few gusts to
20 kt. Wind probs for sustained 18 kt winds remain no higher than 10-
15% through tonight...so will not issue SCAs. The southerly winds
decrease by a couple of knots Thursday morning before increasing
back to 10-15 kt across the bay/15-20 kt on the ocean by late Thu
aftn as the gradient tightens ahead of the approaching cold front. A
few gusts to 25 kt are possible across the ocean between 6 PM-
midnight Thu night. Seas build to ~4 ft with 5 ft seas possible
(mainly N of Cape Charles). SCAs are possible for the VA/MD coastal
waters, but there is not enough confidence to issue them attm. By
Friday, the front will stall over the waters leading to weaker winds
with low confidence in the wind direction. By the weekend, high
pressure will build in bringing benign marine conditions across the
local waters. Unsettled marine conditions are likely from early-mid
next week as Canadian high pressure slowly builds SE from the Great
Lakes and a tropical system potentially forms to our south and
tracks toward the waters. There is a large amount of uncertainty
with respect to the track and strength of any tropical system that
does develop. Regardless of any tropical development, a period of
elevated NE winds appears possible from the early to middle part of
next week.
A Moderate rip risk remains in place through Thursday, dropping to
low on Friday. A low to moderate rip risk is expected this weekend,
with a high rip current risk likely for much of next week due to
swell from any offshore system.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...None.
MARINE...None.
&&
$$
SYNOPSIS...LKB
NEAR TERM...LKB/NB
SHORT TERM...AJZ/NB
LONG TERM...AJZ/NB
AVIATION...AJZ
MARINE...ERI

NWS AKQ Office Area Forecast Discussion