940
FXUS61 KLWX 170756
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
356 AM EDT Sat Aug 17 2024

.SYNOPSIS...
An approaching cold front will bring daily shower and thunderstorm
chances this weekend and into early next week. Dry conditions and
cooler temperatures return Tuesday as high pressure builds in from
the northwest.

&&

.NEAR TERM /THROUGH TONIGHT/...
An approaching cold front will bring widespread shower and
thunderstorm chances to the forecast area this afternoon. As of
3:45 AM, a line of rain showers is moving northeast along the
I-95 corridor. Cloud cover lingering from early morning
precipitation could hinder afternoon shower and thunderstorm
chances. Modest CAPE values of 1000 to 2000 J/kg could lead to
some storms being strong if convection initiates during peak
daytime heating. The primary hazard for today will be heavy
rainfall with isolated instances of flooding. PWAT values
approaching and exceeding 2 inches are expected this afternoon.
The most vulnerable areas will be those in NE Maryland and in
metro areas that are sensitive to urban flooding. Along with
heavy rainfall, damaging wind gusts are the primary threats
expected with convection this afternoon.

High temperatures will be in the 80s for most with some valleys
getting into the 90s. Higher elevations will stay in the 70s.
Overnight low temperatures will dip into the mid 60s to low 70s
areawide.

&&

.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
Daily shower and thunderstorm chances continue Sunday and into
Monday as a cold front approaches and moves through the forecast
area. The greatest chance for thunderstorms will be Sunday
evening and overnight into Monday as the cold front moves
through the area and an upper level trough pivots overhead. Some
storms could be strong with CAPE values between 1000-2000 J/kg,
lapse rates nearing 6 C/km, and bulk shear nearing 30 knots
though parameters remain marginal. Heavy rainfall continues to
be an expected threat with PWATS near or exceeding 1.75 inches.
Showers and an isolated thunderstorm linger Monday in the wake
of the cold front, with conditions less favorable for convection
compared to Sunday and Sunday night.

Temperatures will be slightly cooler on Monday in the way of the
cold front. Highs in the 70s to upper 80s on Sunday will cool to
highs in the upper 60s to lower 80s on Monday. Overnight low
temperatures will be in the upper 50s to 60s each night.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Canadian high pressure will gradually build into the region in the
wake of a frontal passage Monday afternoon and settle overhead by
next Friday. Temperatures will feel more like late September than
late August, some 10 degs below normal.

&&

.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
Sub-VFR conditions are expected at all terminals this weekend as
a cold front approaches and moves through the area. Reduced
ceilings are expected, as well as reduced visibilities during
precipitation. Daily shower and thunderstorms are expected
through Monday with precipitation chances peaking each
afternoon. Outside of showers and thunderstorms, expect
southerly winds gusting to 15 kts this weekend. Winds shift to
westerly and then northwesterly on Monday.

Prevailing VFR conditions are expected throughout the long term
period with no significant weather in the forecast.

&&

.MARINE...
Small Craft Advisory conditions continue today with southerly
winds gusting 20 to 25 kts in the Chesapeake Bay. Winds remain
SCA criteria overnight will diminishing slightly, gusting 15 to
20 kts out of the south. On Sunday, winds remain out of the
south blowing right at or slightly below SCA criteria. Winds
shift to westerly Monday morning before shifting to
northwesterly in the afternoon. Winds are expected to remain
below SCA criteria throughout the day before increasing
overnight Monday into Tuesday. SMWs are possible each afternoon
with daily shower and thunderstorm chances.

SCA conditions are expected Tue into Wed in NW to N flow.

&&

.TIDES/COASTAL FLOODING...
Minor coastal flooding will continue at Annapolis through early next
week in gusty southerly flow.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory until 4 PM EDT this afternoon for MDZ008.
     Coastal Flood Advisory until 7 AM EDT this morning for MDZ014.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 4 PM EDT this afternoon for
     ANZ530>534-537>543.

&&

$$

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