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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KLWX 211913
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
313 PM EDT Sun Apr 21 2024

.SYNOPSIS...
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Low pressure will pass to our south today. High pressure will
build in for Monday and Tuesday. A cold front will move through
Wednesday, with high pressure building in again for the end of
the week.
-- End Changed Discussion --

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
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Low pressure continues to track well to our south this
afternoon. The high cloud shield associated with this system
remains in place across the area. These cloudy skies will
persist through the remainder of the day. The thick cloud cover
has kept temperature down today, with most locations only making
it into the lower 50s. The vast majority of the forecast area
remains dry, but some light rain continues to linger across
southern Maryland. This rain should exit the area to the east
over the next couple hours.

The area of low pressure will depart offshore tonight, allowing
for clearing skies, especially during the second half of the
night. A light northwest wind may continue through a large
portion of the night, but many locations should eventually
decouple closer to daybreak. With an already cool airmass in
place, and the potential for some locations to decouple and
radiate efficiently, it will be a chilly night. Most locations
should drop back into the 30s, with downtown DC and Baltimore
holding in the lower 40s. Outlying locations to the north and
west of I-95 will have the greatest potential for Frost
tonight, with freezing temperatures also possible to the west of
the Blue Ridge. Frost Advisories and Freeze Warnings are in
effect tonight for much of the forecast area to the north and
west of I-95.
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&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
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Upper troughing will push off to our east tomorrow, with
subsidence in its wake leading to sunny skies across the area.
Winds will remain light out of the northwest, and temperatures
will rebound nicely after a cold start. High temperatures will
generally be in the 60s. High pressure will become centered
overhead tomorrow night. Clear skies and calm winds in the
vicinity of the high will lead to ideal conditions for
radiational cooling tomorrow night. Dewpoints will be a bit
higher than today, which will limit how cold it can get, but
most locations should still drop back into the 30s. Additional
Frost Advisories may eventually be needed for tomorrow night.

Upper troughing will dig into the Great Lakes on Tuesday, while
low pressure at the surface tracks across southern Canada. A
trailing cold front will extend southwestward across the Ohio
Valley. The daylight hours on Tuesday look to remain dry, but
high clouds will be on the increase later in the afternoon. High
temperatures will be seasonable Tuesday, with most locations
reaching into the upper 60s and lower 70s. A few showers may
impact the area Tuesday night, with the mountains experiencing
the greatest chance for rain.
-- End Changed Discussion --

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
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An area of low pressure and an associated cold front moves into the
area Wednesday morning. Guidance has continued to trend drier, with
only the upslope of the Allegheny Front seeing decent PoPs as
downsloping flow beyond the mountains suppresses shower
activity. Outside of the upslope areas, some showers could
develop along extreme northern MD, but otherwise shower activity
is looking less likely.

As another area of high pressure moves in behind the system, a tight
pressure gradient between the low pressure and the high pressure on
the back end of the system likely results in gusty winds through
Wednesday night. Northwest gusts up to around 25-30 kt, are expected
for much of the Wednesday afternoon, and up to around 35 kt along
the higher ridges.

Dry conditions return Thursday into Friday with high pressure. The
next chance for precipitation approaches Friday night into Saturday
as a warm front associated with a surface low over the Midwest moves
in from the southwest. Showers and afternoon thunderstorms are
possible Saturday as the warm front moves through the area.

Temperatures on Wednesday will depend on the timing of the cold
frontal passage as temps drop behind it, but could see above normal
temps east of the Blue Ridge before the front in the afternoon.
Thursday and Friday will be cooler, but gradually warming into the
weekend, with above normal temperatures expected Saturday.
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&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
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VFR conditions are expected through Tuesday. Winds are currently
light, but will turn out of the northwest later this afternoon,
and remain northwesterly through the day tomorrow. Winds will
turn southerly on Tuesday, and may gust to around 15-25 knots
during the afternoon hours.

As a cold front moves into the area Wednesday, some showers could
bring sub-VFR conditions to the terminals, but guidance has
continued to trend drier east of the Alleghenies. MRB, BWI and MTN
seem the most likely to receive rain of the terminals, with the
greatest chance during the morning and moving out by evening. Winds
turn out of the NW on Wednesday with gusts 20-25 kt, possibly closer
to 30 kt for MRB. Winds diminish and turn out of the north with VFR
conditions expected.
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&&

.MARINE...
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Sub-SCA northerly winds are ongoing over the waters. Winds will
pick up out of the north later this evening, with SCA conditions
expected overnight. Sub-SCA level northwesterly winds are
expected on Monday. Winds will turn southerly on Tuesday, and
may reach SCA level at times.

As a cold front crosses the waters, gusty northwesterly winds likely
exceed SCA criteria Wednesday through Wednesday night. Winds
diminish and turn out of the north on Thursday.
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&&

.TIDES/COASTAL FLOODING...
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Anomalies remain low over the waters today. No flooding is
anticipated over the next few days, but a few of the more
sensitive locations may reach Action stage.
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&&

.LWX WATCHES/WARNINGS/ADVISORIES...
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DC...None.
MD...Freeze Warning from 2 AM to 8 AM EDT Monday for MDZ003.
     Frost Advisory from 2 AM to 8 AM EDT Monday for MDZ004>006-503-
     505-507.
VA...Freeze Warning from 2 AM to 8 AM EDT Monday for VAZ025>031-507-
     508.
     Frost Advisory from 2 AM to 8 AM EDT Monday for VAZ038>040-050-
     051-501-502-505-506-526.
WV...Freeze Warning from 2 AM to 8 AM EDT Monday for WVZ050>053-055.
MARINE...Small Craft Advisory from 10 PM this evening to 6 AM EDT
     Monday for ANZ530>532-539-540.
     Small Craft Advisory from 10 PM this evening to 10 AM EDT
     Monday for ANZ533-534-537-541-543.
-- End Changed Discussion --

&&

$$

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