863
FXUS61 KLWX 181434
AFDLWX
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1034 AM EDT Thu Jun 18 2026
.WHAT HAS CHANGED...
This morning`s severe weather threat with a decaying
thunderstorm complex has likely diminished and the Severe
Thunderstorm Watch has been cancelled. How the remainder of the
day unfolds remains uncertain, but the greatest risk for a
second round of strong to severe thunderstorms may mostly be
across the southern parts of the forecast area. With debris
clouds around a good portion of the day, did lower high
temperatures a few degrees based on the latest guidance.
&&
.KEY MESSAGES...
- 1) Hotter conditions return today with potential for severe
thunderstorms and strong gradient winds.
- 2) A strong low pressure system could bring the threat for
heavy rainfall and thunderstorms late Sunday through Monday.
- 3) An active upper-level pattern could bring continued rain
chances through mid-week.
&&
.DISCUSSION...
KEY MESSAGE 1...Hotter conditions return today with potential
for severe thunderstorms and strong gradient winds.
A cold front will drag across the region later this afternoon
through early Friday. Hotter temperatures than yesterday
expected this afternoon with highs in the middle 70s to middle
80s west of the Blue Ridge and highs in the lower 90s east of
the Blue Ridge. Heat index values should mostly remain in the
mid 90s. This heat, combined with effects from increasing
humidity and wind shear in all levels could spawn some strong to
severe thunderstorms across most of our region. There is some
uncertainty as to the area extent of such strong to severe
thunderstorms given the most recent nighttime convection, cloud
cover, and expected slightly cooler temperatures in the
aforementioned zones of our northwestern third of our region.
This may be limited to southern portions of the area later this
afternoon after some recovery occurs. The main threat will be
damaging winds. Lightning may also become a big factor with the
strongest thunderstorms. Not only will damaging winds be
anticipated in strong to severe thunderstorms, but also from a
synoptic or gradient viewpoint as well. Winds just above the
boundary layer are very strong due to a low-level jet. A Wind
Advisory remains in effect throughout the Alleghenies, interior
western zones, and the northern Blue Ridge. Thanks to the
morning rain and clouds, the worst of the low level jet may not
mix down. However, some very gusty winds could still occur this
afternoon as mixing increases, so will leave the advisory for
now.
The cold front will push southward tonight. The front will
absorb an area of low pressure to the south, likely originating
from Arthur. There is still some spread with how far north
additional rain reaches, but some rain chances will linger
across the southern half of the area in particular through
Friday morning. Skies should clear through the day with lowering
humidity and seasonable temperatures.
KEY MESSAGE 2...A strong low pressure system could bring the threat
for heavy rainfall and thunderstorms late Sunday through Monday.
After a mainly quiet weekend across the region, there is an
increasing signal of active weather returning late Sunday into
Monday. Looking aloft first, the key players are a compact upper low
dropping southeastward from the Great Lakes as well as an open wave
ejecting eastward from the Ohio Valley. The combination of these
features will fuel increasing lift across the Mid-Atlantic region.
While the accompanying surface low is more modest in nature compared
to the one today/Thursday, it still may feature a 1000-mb surface
pressure. Ensemble spread is notable as this low tracks across the
Ohio Valley toward the Mason-Dixon Line. Where this low tracks and
how quickly the warm sector crosses the local area will drive the
degree of instability in the atmosphere. One aspect of the forecast
that does appear a bit more certain is anomalous moisture tracking
up the Eastern Seaboard on Monday. The heavy rainfall signal is
certainly non-zero, but still bears watching as models continue to
resolve the more complex details.
KEY MESSAGE 3...An active upper-level pattern could bring continued
rain chances through mid-week.
As the early week system drives a cold front offshore early Tuesday,
there is a loose ensemble signal of additional unsettled conditions
through mid-week. Mid/upper heights begin to build across the Desert
Southwest into northwestern Mexico. At the same time, cyclonic flow
across south-central Canada begins to dig toward the Midwest and
northeastern U.S. Forcing from this trough could again increase
shower and thunderstorm chances across the region. At this point,
uncertainty is high across the board as shown by the low
probabilities for rainfall in the forecast. Temperatures appear
seasonable heading into mid-week with a gradual uptick in humidity
levels.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
The decaying thunderstorm complex/linger showers should clear
most of the terminals by late morning. This may largely squash
the thunderstorm potential for the remainder of the day so have
removed the PROB30s. The exception is CHO, where some guidance
shows scattered thunderstorms potentially developing late this
afternoon. Can`t rule out something isolated happening elsewhere
as a cold front drops down, but overall the risk may be
diminishing. As the clouds thin, a southwest wind gradient
increases this afternoon and gusts could exceed 30 knots at
times.
Another round of showers could affect portions of the area
tonight into Friday morning as low pressure passes to the south,
but impacts are uncertain. Skies should gradually clear Friday
with gusty northwest winds.
Gusty NW winds around 20-25 kts can be expected Saturday. While
VFR conditions are expected for much of Sunday, there is an
increasing signal of heavy rainfall and thunderstorms toward the
night and into Monday. Depending on how this plays out,
restrictions would become more likely. Initial winds on Sunday
begin out of the west-southwest before shifting over to
southeasterly by the evening/night. A return to westerlies is
expected for Monday with gusts increasing to around 15 to 20
knots.
&&
.MARINE...
Southwest winds are expected to increase through today, though
they are a bit delayed thanks to morning rain. Gale Warnings
are in effect for the northern Chesapeake Bay and upper tidal
Potomac, although this will admittedly be marginal. Otherwise
SCAs are in effect through early evening, which may need to be
extended slightly. The strongest gusts will be near the shore
this afternoon as air temperatures rise toward 90. Special
Marine Warnings may be needed during the afternoon and early
evening as scattered strong to severe thunderstorms potentially
track over the waters, with the greatest chances across southern
Maryland.
There may be a bit of a break in the winds tonight as the front
slows down. Marginal Small Craft Advisories may be needed for
portions of the waters Friday in northwest flow.
Winds on Saturday will be out of the NW and near SCA criteria in the
wake of a secondary cold front. Winds will likely taper off
into Saturday evening as they gradually turn out of the south.
Sub-advisory level winds are expected for Sunday before hazardous
conditions return to the forecast on Monday. Increasing south to
southwesterly winds may lead to Small Craft Advisories across the
area waterways.
&&
.TIDES/COASTAL FLOODING...
Anomalies are peaking around 1-1.5 ft this morning. Advisories
remain in effect for Annapolis and Havre de Grace. Adding in
Alexandria, but other locations should remain below minor
thresholds. Water levels will then dip in the wake of a cold
front.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Gale Warning until 8 PM EDT this evening for MDZ008.
Coastal Flood Advisory until 1 PM EDT this afternoon for
MDZ014.
Wind Advisory until 6 PM EDT this evening for MDZ501-502-509-
510.
Coastal Flood Advisory until 4 PM EDT this afternoon for
MDZ508.
VA...Wind Advisory until 6 PM EDT this evening for VAZ503-504-507.
WV...Wind Advisory until 6 PM EDT this evening for WVZ050-055-
501>506.
MARINE...Gale Warning until 8 PM EDT this evening for ANZ530-531-535-
538.
Small Craft Advisory until 8 PM EDT this evening for
ANZ532>534-536-537-539>543.
&&
$$
DISCUSSION...ADS/BRO/KLW
AVIATION...ADS/BRO/KLW
MARINE...ADS/BRO/KLW
NWS LWX Office Area Forecast Discussion