Towson, Maryland 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

892
FXUS61 KLWX 141332
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
932 AM EDT Wed May 14 2025

.SYNOPSIS...
An upper low will slowly drift northeastward toward the area
today, before shearing out into an open wave and lifting to our
northeast on Thursday. An area of low pressure will track
toward the Upper Midwest and Western Great Lakes by Friday,
before tracking eastward across Quebec and Ontario this weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
Latest water vapor satellite imagery continues to depict a
potent upper-low spinning across the lower Ohio Valley into the
southern Appalachains. Showers are pivoting to the northeast
concurrently with the low level jet associated with this system,
which is pushing further to our east with each passing hour.
A few showers are lingering across northeastern Maryland, and
will likely do so for the next hour or two. Thankfully, have
seen a downward trend in intensity in the last hour, so not
expecting to see any sort of flooding threat develop from this
feature.

After this departs, all that is left is some light
drizzle/showers, which should decrease in coverage by around
noon or so. This break in the rain has allowed most of our
small streams to recede. However, mainstem river flooding will
continue to be an issue for at least the next 24 to 48 hours.

PREVIOUS DISCUSSION: The upper-low will begin opening as it
continues northeast today. While cloud breaks might be limited,
especially across the northern half of the area, some low level
drying may begin to take place, allowing instability to build,
especially over the southern half of the area. A vort max will
approach during peak heating, and with little inhibition,
widespread showers and scattered thunderstorms are expected to
develop by afternoon. This activity should gradually spread
northeastward through the remainder of the afternoon and
evening. Shear will be marginal, around 20-30 kt, but this could
support a few stronger storms. Lowering freezing levels suggest
a hail threat, but the marginal shear combined with moist
profiles will likely limit the threat for severe winds and hail.
00Z CAMs suggest the strongest storms will be over southeastern
Virginia, perhaps making a run toward the lower Potomac area.
The severe threat will lessen with northward extent due to
decreasing instability. Renewed flooding will also be a concern.
Heavy rain will not be as widespread as Tuesday with average
rainfall amounts less than an inch expected. Precipitable water
values are also lower, and the forcing should be somewhat
progressive. However, slow storm motions less than 20 kt could
pose an issue in any storms that could produce rain rates of
1-1.5 inches in an hour or two. At the moment, the threat for
flooding seems to be isolated. However, given many sensitive
areas and high streams across the area, this will continue to be
evaluated. Temperatures should push into the 70s for most
areas, warmest in the southwest.

Remnant showers will gradually lift to the northeast tonight
with low clouds and fog possible again. Lows will be in the mid
50s to mid 60s.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
The weakening trough axis and possible weak surface low will be
near the Chesapeake Bay Thursday morning. This means any
remaining showers northeast of the Potomac should pivot away
during the morning hours. More breaks of sun are likely, which
will allow temperatures to rise toward 80. Not a lot of
confidence in the precipitation forecast thereafter. Advection
of a high theta-e airmass will be approaching from the west.
Other than possible terrain lift, forcing is otherwise nebulous
through the day. However, CAMs suggest some storms may develop
over the central Appalachians at a minimum. Given steepening
lapse rates and increasing shear, some storms could be severe.
However rising heights could limit storm strength. SPC has added
a Marginal Risk for severe for now.

The uncertainty theme continues Thursday night through Friday
night as possible upstream convection moves toward the area. The
airmass will be characterized by steep lapse rates and strong
shear, so storms may be able to maintain themselves. Depending
on how the airmass is modified by upstream convection, Friday
in particular could have a high end CAPE/shear parameter space
across the area. However, the atmosphere may remain capped with
little to no storm development. Hopefully this becomes clearer
with time. What`s more certain is that it will turn hot and
humid Friday, with highs well into the 80s and dew points in the
mid 60s to lower 70s.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
A low pressure system will bring a cold front across the region
on Saturday. Showers and thunderstorms will develop ahead of
and along this front Saturday afternoon. Temperatures will be on
the warm side with highs in the middle 80s.

A drier day in store for the region Sunday through Tuesday with high
pressure building across the region. Highs in the upper 70s to lower
80s with lower humidity.

The next chance for showers or thunderstorms could come with a front
late Tuesday into Tuesday night.

&&

.AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
Light rain and drizzle continue across all terminals at this
time, accompanied by IFR to LIFR CIGs. This should gradually
start to improve to some extent through mid-late morning as
drier air starts to push into the region from the SW. Starting
to see some evidence of improvement at CHO already in terms of
VSBYS, but not expecting CIGs to improve substantially until
probably close to noon.

Ceilings will gradually lift to MVFR and potentially even VFR
during the afternoon hours. Showers and thunderstorms will form
during the afternoon, generally progressing southwest to
northeast. Thunderstorms are most likely at CHO, but may be more
scattered once they reach the metro terminals (thus PROB30
groups for now). Showers may linger at BWI/MTN into the night.
Otherwise, expect a return to IFR to perhaps LIFR ceilings.
Light E to S winds are expected through the TAF period.

Conditions improve to VFR on Thursday. The highest chance for an
afternoon/evening thunderstorm appears to be at CHO, but this is
highly uncertain. Sub-VFR conditions (ceilings or fog) may
return to mainly MRB/BWI/MTN Thursday night. There is also
potential for one or more rounds of showers and thunderstorms
late Thursday night through Friday night, but details are very
uncertain at this time.

MVFR conditions could arise with showers and thunderstorms Saturday
afternoon into early evening. Winds will be southerly before
shifting to southwesterly by Friday. Winds southwest becoming west 5
to 10 knots Saturday and Saturday night. Winds west becoming
northwest 5 to 10 knots Sunday and Sunday night.

&&

.MARINE...
With the latest forecast package this morning, SCAs were
cancelled in the northern Chesapeake Bay, so no marine hazards
are in effect at this time. Winds will generally diminish today
as the low-level jet continues its departure north and east.

For the remainder of the day, light east to south winds are
expected through Thursday. Strong thunderstorms could approach
from the south later this afternoon into the evening, which
could warrant Special Marine Warnings.

South to southwest winds should remain sub-SCA Thursday night through
Friday night . The main concern will come from thunderstorms,
although the timing, coverage, and strength of any storms is
very uncertain at this time.

Showers and thunderstorms that develop Saturday afternoon over or
near the waters could pose for a Special Marine Warning in places.
Otherwise, no marine hazards expected Saturday night through Sunday
night. Winds southwest to west 10 knots Saturday and Saturday night.
Winds becoming northwest 10 knots Sunday.

&&

.TIDES/COASTAL FLOODING...
Tidal anomalies have really fallen off this morning, down to
around 1-1.25 feet above normal at this time. Many of the
Coastal Flood Advisories that were in effect have either come
and gone, or never quite reached minor flood stage to begin
with. General improvement is expected for most in the coming
days, but a generally light southerly flow will continue to
bring the more sensitive tidal sites near/into action stage.
However, Georgetown will likely have some freshwater related
flooding by Thursday, and a Coastal Flood Watch remains in
effect for this threat. Current forecast brings Georgetown to
Moderate for much of the day on Thursday as a result of the
freshwater influence flowing down from the west.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Coastal Flood Watch from Thursday morning through Friday
     afternoon for DCZ001.
MD...Coastal Flood Advisory until 10 AM EDT this morning for MDZ011-
     014.
     Coastal Flood Advisory until 3 PM EDT this afternoon for
     MDZ508.
VA...None.
WV...None.
MARINE...None.

&&

$$

SYNOPSIS...ADS
NEAR TERM...ADS/CJL
SHORT TERM...ADS
LONG TERM...KLW
AVIATION...ADS/KLW/CJL
MARINE...ADS/KLW/CJL
TIDES/COASTAL FLOODING...CJL