National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS61 KLWX 130800
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
400 AM EDT Sat Apr 13 2024

.SYNOPSIS...
Low pressure will continue to lift northward into Canada today
as high pressure builds to our south. A weak area of low
pressure will track to our north on Sunday, eventually pushing a
weakening cold front southward through the area late Sunday
night into Monday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 330 AM, the bulk of the showers have progressed out of the
forecast area, with just a few sprinkles remaining. Dry
conditions are expected for all by daybreak, but winds will
remain gusty in the wake of a reinforcing cold front that passed
through overnight.

Low pressure will continue to lift northward into Canada today
as high pressure simultaneously builds to our south. This will
maintain a strong pressure gradient across the forecast area,
and cause winds to remain gusty through the day. A Wind
Advisory is in effect through 6 PM for all locations to the
west of the Blue Ridge, as well as the DC and Baltimore metros.
Gusts of 40-55 mph out of the west-northwest will be common
within the Wind Advisory area through the day. Skies are
currently mostly cloudy, but dry advection at low levels and
increasing large scale subsidence behind a departing upper trough
will cause clouds to dissipate over the course of the morning,
leading to sunny skies during the afternoon. High temperatures
today will reach into the 60s for most, with 50s in the
mountains.

Winds should decrease rather abruptly this evening with loss of
daytime heating and resultant mixing. Skies will remain mostly
clear overnight, with temperatures dropping back into the 40s.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
Flow aloft will become more zonal in nature tomorrow, with a
broad belt of west-southwesterly flow extending from the Upper
Midwest toward the East Coast. A shortwave disturbance will
descend down in the west-northwesterly flow from the Great Lakes
toward Upstate NY. A weak area of low pressure will accompany
the shortwave, along with an attendant cold front which will
drop southward out of NY into northern PA Sunday afternoon.
Locally, it will be a warm day to the south of the boundary,
with temperatures climbing into the upper 70s to near 80 beneath
partly cloudy skies. Thunderstorms are expected to form near the
aforementioned frontal boundary up in PA Sunday afternoon. Much
of this activity is expected to remain to our north during the
daylight hours.

As we move into the evening and the first half of the
overnight, these storms are expected to drift southward along
with the frontal boundary, eventually reaching northern portions
of the forecast area. With loss of daytime heating, the trend
should be for these storms to gradually weaken as they move in
from the north, but a few stronger storms can`t be ruled out.
The environment will be an uncommon one for this part of the
country, with steep lapse rates of 7-8.5 C/km in place as an
elevated mixed layer moves in aloft. If storms do persist as
they track into the area, some instances of large hail may be
possible. SPC currently has portions of northern Maryland and
the West Virginia Panhandle outlooked in a Marginal Risk for
severe thunderstorms.

The frontal boundary will continue to drift southward across the
area on Monday. A few storms may try to form along the front
from central Virginia to southern Maryland Monday afternoon, but
conditions should remain dry for the vast majority of the
forecast area. High temperatures will range from the mid 70s
across northern Maryland to the lower 80s from central Virginia
to southern Maryland.


&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
A progressive active pattern persists through a good chunk of the
work week. While one longwave trough departs into the Canadian
Maritimes, the next system takes aim at the region by the second
half of Wednesday. By Friday into the next weekend, an expansive
upper low descending from central Canada settles into the
northeastern corridor of the U.S. This final system in the chain
will eventually bring an end to the stretch of above average
temperatures. The lengthy period of mid 70s to low 80s should be
replaced by mid 60s to low 70s by Friday. This trend continues into
next weekend with highs falling into the upper 50s to mid 60s.
Overall ensemble spread for the temperature forecast is remarkably
low through Thursday. Thereafter, uncertainty looms with the timing
and extent of the cold surge.

Looking more closely at the the forecast, a backdoor front briefly
pushes south of the area on Tuesday. However, an increasing
southerly surge draws this boundary northward as a warm front on
Wednesday. This also introduces more humidity into the air as dew
points rise above 60 degrees. As this warm/humid air mass moves in,
expect increasing chances for showers and thunderstorms,
particularly as the upstream shortwave trough tracks across the Ohio
River Valley. This eventually drags a weak cold front through the
local area early Thursday. On its heels will be a stronger cold
front which is tied to the deep upper trough dropping down from
central Canada. Ascent along this boundary yields additional rain
showers along with a shift to west-northwesterly flow on Friday.
Although far out into the forecast period, winds may become gusty at
times given the strength of the boundary and trough.

&&

.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
VFR conditions are expected through Monday. Just a few lingering
sprinkles remain across the forecast area, and those are
expected to exit prior to daybreak. Gusty west-northwesterly
winds are expected to persist throughout the day. Frequent gusts
of 35-45 knots are expected through the morning, with winds
slowly weakening through the afternoon. Winds should abruptly
decrease further after dark. Winds tomorrow will turn out of the
southwest, and may gust to around 20-30 knots at times.
Northwest winds are forecast for Monday, with gusts of 15-20
knots possible at times.

A backdoor cold front will drop southward through the area on
Tuesday. This leads to a period of easterly onshore flow through
midday Tuesday. However, expect a return to southerly flow as this
boundary lifts northward as a warm front. Winds should persist out
of the south through Wednesday, accompanied by afternoon gusts up to
25 knots. A threat for showers and thunderstorms exists each day,
particularly on Wednesday. Thus, there may be some periods of
restrictions, although much of the day should yield VFR conditions.

&&

.MARINE...
Gusty west-northwesterly winds will continue through the day
today. Gale Warnings remain in effect for all waters through 6
PM. There should be a fairly sharp drop off in winds this
evening, but a Small Craft Advisory may be needed for a few
hours after the Gale Warning ends. Small Craft Advisories will
likely be needed again tomorrow in southwesterly flow. Sub-SCA
northwesterly winds are expected on Monday.

Aside from a brief period of easterly flow due to a backdoor cold
front, expect mainly southerly flow over the waters through mid-
week. A large ramp up in winds fields is expected on Wednesday with
gusts up to 25 knots. Thus, Small Craft Advisories will likely be
needed then. Convective threats pick up on Wednesday which may
require Special Marine Warnings for any stronger showers and/or
thunderstorms.

&&

.TIDES/COASTAL FLOODING...
A strong offshore flow has developed and will continue through
the day today before gradually weakening this evening.
Anomalies will continue to fall during this time. The change
from high anomalies yesterday to lower anomalies today will
cause a strong current during this time. Thereafter, water
levels are expected to remain below Minor flood stage for the
next several days.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Wind Advisory until 6 PM EDT this evening for DCZ001.
MD...Wind Advisory until 6 PM EDT this evening for MDZ001-003>006-
     008-011-013-014-501>508.
VA...Wind Advisory until 6 PM EDT this evening for VAZ025>031-040-
     053-054-501-503>508-526.
WV...Wind Advisory until 6 PM EDT this evening for WVZ050>053-055-
     501>506.
MARINE...Gale Warning until 6 PM EDT this evening for ANZ530>543.

&&

$$

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