079
FXUS61 KLWX 031939
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
339 PM EDT Wed Sep 3 2025

.SYNOPSIS...
A cold front will approach from the west on Thursday, before
decaying overhead. A much stronger cold front will move through
Saturday. High pressure will build in from the Ohio Valley early
next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Broad upper troughing remains in place over the eastern half of
North America. A weak shortwave is approaching from southwest
Virginia. Ascent ahead of this feature may be enough to spark
the development of a few showers, and potentially a thunderstorm
or two across the Potomac Highlands this afternoon. Elsewhere,
dry conditions are expected, with just a few fair weather
cumulus clouds. Southerly flow has allowed slightly warmer air
to work into the area, with temperatures climbing into the lower
80s in most locations.

Increasing southerly flow may prevent most locations from
decoupling overnight, which will keep temperatures a bit warmer
than preceding nights. Dry conditions and mostly clear skies are
expected, with overnight lows generally in the upper 50s and
lower 60s.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
A deep upper low will lift from near Lake Superior toward Hudson
Bay tomorrow. Meanwhile, an accompanying shortwave will drop southward
toward Lower Michigan tomorrow morning, before lifting
northeastward toward the St. Lawrence Valley tomorrow afternoon.
This system will drive a cold front southeastward toward the
area, but the front will ultimately wash out over the area
tomorrow night as it loses upper air support. Thunderstorms are
expected to develop tomorrow afternoon as large scale ascent
associated with that system overspreads a destabilizing airmass.
Temperatures should reach well into the 80s for most tomorrow,
with dewpoints potentially climbing into the low-mid 60s.
Isolated showers may reach the Allegheny Front as early as late
morning, but more scattered to widespread shower/thunderstorm
activity is expected to develop tomorrow afternoon. These storms
will likely impact locations to the west of the Blue Ridge
between roughly 1-5 PM, and locations to the east of the Blue
Ridge from 3-9 PM.

Model soundings show around 500-1000 J/kg of MLCAPE, with around
35-40 knots of effective bulk shear. Hodographs are relatively
straight, with near unidirectional southwesterly flow. Much of
the shear is present in the lowest 3 km. DCAPE appears to be on
the lower side, with relatively moist mid-levels. However, most
models show well mixed subcloud layers with relatively steep
low- level lapse rates. CAMs show a mixed multicell/marginal
supercell mode. Small bowing segments may be capable of
producing damaging winds, and any supercells could produce
either damaging winds or hail. Supercell splits may be possible
given the straight hodograph shape. HREF UH tracks hint at this
potential, showing both positive and negative UH swaths, albeit
relatively weak in magnitude. SPC currently has much of the area
outlooked in a Marginal risk for severe thunderstorms.

Any thunderstorm activity should weaken and/or progress off to
our southeast by late evening, resulting in dry conditions
overnight. Lows tomorrow night should be in the upper 50s to
the west of the Blue Ridge, with low to mid 60s further east.

Height rises will ensue aloft between disturbances on Friday.
The vast majority of guidance keeps conditions dry, although the
3km NAM does have a few thunderstorms forming during the
afternoon along a surface trough. Warmer temperatures are
forecast for Friday, with highs reaching into the mid 80s to
near 90.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
A cold front is set to move across the area to start the weekend,
bringing at least scattered showers and thunderstorms. There should
be sufficient instability for convection during the afternoon to
early evening as temps climb to the mid to upper 80s, especially
east of the Blue Ridge. Dew points are also going to be in the mid
to upper 60s, and close to 70F in Central VA to along I-95. Looking
at model soundings it is definitely possible that we see severe
thunderstorms in the area. Deep-layer shear around 40-50 knots
and steep low-level lapse rates could result in organized
convection capable of damaging wind gusts.

High pressure quickly builds into the region Saturday night and
persists into the start of next week. Dry, much cooler, fall-like
weather returns Sunday as highs only reach the low to mid 70s. Highs
in the mid 70s for Monday and Tuesday. Overnight lows drop to the
upper 40s to 50s.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
VFR conditions and light southerly winds are expected this
afternoon through tonight. Winds will pick up out of the south
tomorrow, and then turn out of the southwest tomorrow afternoon.
Winds may gust to around 20-25 knots tomorrow afternoon.
Thunderstorms will also move in from the west tomorrow
afternoon. Any storms tomorrow afternoon could produce damaging
winds. Coverage of the storms won`t be overly impressive, so
just PROB30 groups have been introduced for now. Timing for the
DC/Baltimore metros looks to be between 4 and 9 PM (a bit
earlier further west).

Sub-VFR conditions are possible Saturday afternoon as a cold front
brings scattered showers and thunderstorms to the area. High
pressure builds in behind the front Saturday night into Sunday,
bringing VFR conditions and breezy north winds.

&&

.MARINE...
Winds remain light out of the south over the waters this
afternoon, but they will begin to pick up this evening. SCAs are
in effect for portions of the main channel of the Bay tonight
within channeled southerly flow. SCA conditions are expected for
all waters within south to southwesterly flow during the day
tomorrow. SMWs may also be needed late tomorrow afternoon into
tomorrow evening as thunderstorms move over the waters. SCA
conditions will likely linger through much of the night Thursday
night within southerly flow. Borderline SCA level winds appear
possible within southerly flow Friday into Friday night.

A cold front will move across the area sometime Saturday, bringing
scattered showers and thunderstorms to the waters. Behind the front
period of northerly channeling could produce SCA conditions Saturday
evening into Saturday night. High pressure builds in from the north
on Sunday, though northerly winds could remain elevated through
Sunday evening.

&&

.TIDES/COASTAL FLOODING...
Water levels are starting to increase within southerly flow.
Confidence in Annapolis reaching minor flood increases tonight.
A Coastal Flood Advisory is in effect for Annapolis tonight.
Peak water anomalies appear to occur Thursday night ahead of a
front in strong southerly flow. More locations may reach minor
flood, and some guidance has Annapolis approaching moderate
flood. A Coastal Flood Watch is in effect for Annapolis for the
tide cycle Thursday night. Water levels may decrease a bit
Friday as the first front fizzles out, but minor flooding may
still occur at Annapolis Friday night as southerly flow
strengthens again ahead of the next front. This front will bring
a wind shift Saturday which will decrease water levels.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory from 11 AM Thursday to 2 AM EDT Friday
     for MDZ008.
     Coastal Flood Advisory from midnight tonight to 7 AM EDT
     Thursday for MDZ014.
     Coastal Flood Watch from late Thursday night through Friday
     morning for MDZ014.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 11 AM Thursday to 2 AM EDT Friday
     for ANZ530-535-536-538>540.
     Small Craft Advisory from midnight tonight to 2 AM EDT Friday
     for ANZ531-532.
     Small Craft Advisory from midnight tonight to 6 AM EDT Friday
     for ANZ533.
     Small Craft Advisory from 11 AM Thursday to 6 AM EDT Friday
     for ANZ534-537-541>543.

&&

$$

SYNOPSIS...KJP
NEAR TERM...KJP
SHORT TERM...KJP
LONG TERM...KRR
AVIATION...KJP/KRR
MARINE...KJP/KRR
TIDES/COASTAL FLOODING...LWX