891
FXUS61 KLWX 190756
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
356 AM EDT Tue Aug 19 2025

.SYNOPSIS...
A frontal boundary will remained stalled near the Virginia/North
Carolina border through tonight before slowly returning near the
area by mid-week. Eventually this system pulls away toward the
southeast as a cold front by Thursday. Weak high pressure builds
across the region late in the week into Saturday. An area of low
pressure will track toward Hudson Bay over the weekend. The
associated cold front will move through early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
At the surface, a strong anticyclone sits over central Quebec
while high pressure extends southward into the northeastern U.S.
To the south of this ridge axis, a wavy frontal zone remains
across the Virginia Tidewater region down into the coastal
Carolinas. This cold air damming (CAD) signature has allowed for
persistent onshore flow across the Mid-Atlantic region. The
prevailing east to northeasterly winds has maintained a fairly
thick low stratus deck over the local area. Per the latest
aircraft soundings, the moist easterly flow has generally
saturated the lowest 1 km of the troposphere. These are even
aiding in some drizzle or light showers south of I-95 in
Maryland. Any corresponding rainfall amounts will remain very
light given the weak vertical motions occurring. While some
patchy fog is possible, the presence of low clouds and elevated
wind fields should mitigate this threat.

Unless there is some shift in the winds, expect a persistence of
low stratus and areas of drizzle throughout the day. The
influence of this air mass will yield only minimal temperature
gains through the day. As of 07Z/3 AM this morning, current
temperatures are mainly in the mid 60s to low 70s. Such numbers
likely only rise by around 4 to 8 degrees which raise highs into
the low/mid 70s. While these high temperatures are around 10 to
15 degrees below mid-August climatology, it does not appear any
cool temperature records will occur. For August 19th, the daily
climate sites have record cool high temperatures mainly in the
upper 60s.

A steady easterly wind may gust up to 15 mph at times,
particularly during the afternoon hours. Any light shower
activity is mainly expected for areas along and east of U.S.
15. Rainfall totals should largely top out below a tenth of an
inch, but a tad higher over southern Maryland where a quarter of
an inch is possible. The stable nature of the air mass should
keep any thunder chances toward the Northern Neck of Virginia.

Continued onshore flow will maintain the low diurnal range of
temperatures. Expect nighttime low temperatures in the 60s,
with perhaps 70 degree readings inside D.C. and Baltimore. Areas
of drizzle and fog are again possible overnight.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
After a pair of days with well below average temperatures,
expect a marked warmup on Wednesday. The mentioned frontal zone
near the Virginia/North Carolina border eventually adjoins a
warm front across the Ohio Valley. This entire boundary tracks
northward as a warm front early Wednesday. Generally arcing
southeastward from western Pennsylvania down to southeastern
Virginia, this frontal zone will increase warmth and convective
potential through the day. Forecast highs should rise into the
low/mid 80s (70s for the mountains).

Mid/upper heights gradually lower on Wednesday while the
circulation from Hurricane Erin tracks northward, well offshore
of the southeastern U.S. coast. The former will aid in
triggering diurnal convection across the Alleghenies toward the
I-81 corridor. This is supported by the 00Z HREF 40 dBZ
paintball plots. While lapse rates are not optimal, there is
some dry air aloft to foster isolated stronger gusts. Any threat
of thunderstorms wanes after sundown. A few showers may linger
into the overnight hours as the frontal zone meanders about the
region. Nighttime temperatures are forecast to fall into the mid
60s to low 70s, slightly cooler in the higher terrain.

On Thursday morning, the frontal boundary nearby begins to
accelerate toward the southeast as a cold front. As this occurs,
Hurricane Erin is expected to be a couple hundred miles offshore
of the Outer Banks of North Carolina. Despite its position well
southeast of the Mid-Atlantic region, an uptick in synoptic
winds is likely. The current forecast calls for high
temperatures in the mid 70s to low 80s, but with northerly gusts
of 15 to 25 mph. While some showers are possible, much of the
day is likely dry with the post-frontal wind shift to northerly.
This cold advection regime will make for a cooler night on
Thursday. Low temperatures are expected to drop into the upper
50s to mid 60s (mid/upper 50s for mountain locales).

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
The National Hurricane Center has Hurricane Erin tracking well off
the coast of New England on Friday as surface high pressure builds
over the Mid-Atlantic. Primarily dry conditions are expected on
Friday with high temperatures in the 80s for most. Those at higher
elevations will stay in the 70s.

Over the weekend, an upper level trough pivoting over the Great
Lakes region will push a cold front towards the forecast area. The
front is forecast to push across the Mid-Atlantic Sunday into Monday
morning. This will bring daily precipitation chances. High
temperatures each day will be in the low to mid 80s for most with
higher elevations staying in the 70s. Overnight low temperatures
will be in the 50s to 60s. Conditions dry out in the wake of the
frontal passage Monday afternoon as high pressure builds in from the
west.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
The cold air damming signature will maintain a continued onshore
east-northeasterly wind. This maintains a lengthy period of low
stratus which support ceilings between 800-1500 feet. Expect IFR
ceilings to start the day before meandering between IFR/MVFR
through the remainder of the day. Any visibility restrictions
should be more temporary and driven by intermittent showers.
Such showers likely focus along and east of U.S. 15. with any
threat for thunder well to the south. Otherwise, east-
northeasterly winds persist throughout the day with possible
gusts up to 10 to 15 knots at times. Given little change in the
pattern, IFR ceilings are likely again tonight owing to
persistent low stratus.

On Wednesday, the frontal zone to the south eventually begins to
move across the area as a warm front. Depending on its location,
a gradual shift to southeasterly winds are expected on
Wednesday. Some restrictions are possible in the morning as low
ceilings continue. Some afternoon showers and thunderstorms may
impact the more western TAF sites. The frontal zone eventually
pulls away from the region late Wednesday into Thursday as a
cold front. In the wake, increasing north-northeasterly winds
are likely with gusts up to 15 to 20 knots, perhaps a bit higher
depending on Hurricane Erin`s influences. A few showers are
also possible on Thursday as the system pulls away.

Easterly winds Friday morning shift to southerly Friday night and
Saturday. Winds gust around 10 knots Friday before increasing to 10
to 15 knots on Saturday. Prevailing VFR conditions are expected
although flight restrictions are possible on Saturday during
precipitation.

&&

.MARINE...
Small Craft Advisories continue across the more southern
portions of the waters. These remain in effect until 6 AM this
morning with east-northeasterly gusts up to 20 knots. It
remains to be seen just how persistent these winds are
throughout the day. The cooler air overriding the mild waters
should help lead to better vertical mixing than typically for
the time of year. Thus, Small Craft Advisories may get extended
for portions of the waters.

After a temporary reprieve in the winds, another round of gusty
conditions are expected late Wednesday into Thursday. This is in
response to the expanding wind field of Hurricane Erin.
Northerly gusts of 20 to 25 knots are looking likely, possibly
up to 30 knots over the more southern waters. Will continue to
monitor the potential of any gale conditions.

Winds drop below SCA criteria Friday afternoon, blowing out of
the east between 10 to 15 knots. Winds increase on Saturday,
with Small Craft Advisory conditions likely. Southerly winds
gust 15 to 20 knots.

&&

.TIDES/COASTAL FLOODING...
Anomalies will remain elevated within easterly onshore flow
through much of the week. The greatest chance for coastal
flooding looks to be tonight, when more sensitive sites such as
Annapolis may approach Moderate flood stage. Additional coastal
flooding may be possible on Thursday as Hurricane Erin
progresses offshore. The latest Stevens Ensembles support this
marked uptick with coastal flooding possible across more of the
region.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 6 AM EDT early this morning for
     ANZ533-534-537-541-543.

&&

$$

SYNOPSIS...BRO
NEAR TERM...BRO
SHORT TERM...BRO
LONG TERM...AVS
AVIATION...AVS/BRO
MARINE...AVS/BRO
TIDES/COASTAL FLOODING...BRO/KLW