Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 281431
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1031 AM EDT Thu Mar 28 2024

.SYNOPSIS...
As a cold front pushes east today, low pressure will move
northeastward off the coast. High pressure will build to our
south on Friday. Multiple upper level disturbances will pass
overhead this weekend into early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
The cold front from this morning has largely pushed through the
area this morning, with continued showers east of where it
hasn`t cleared yet, mainly across southern MD at this time. Some
light showers/drizzle are possible as far east as the I-95
corridor through the morning hours, but should quickly push
east after noon.

Meanwhile, and area of low pressure is developing and moving
northward along the NC/VA coastline at this time. The low won`t
move north of our latitude until this evening, so at least
occasional light rain may linger, mainly along the Chesapeake
Bay, through the afternoon. The forecast timing may be on the
pessimistic side, especially if dry air can chip away at the
back side of the rain. Even where rain does end, clouds will be
slow to clear with the upper trough overhead. The best
opportunity to see sun this afternoon will be west of the Blue
Ridge. Given the recent radar trends, likely won`t see much more
than a half inch of rain across southern MD for the rest of the
event. Elsewhere, we likely won`t see more than a few hundredths
of an inch of QPF.

Northwesterly winds will increase behind the front as well with
20-25 mph gusts likely (higher on the ridges). Temperatures
will only rise a little into the lower and mid 50s across most
of the area, although some upper 50s to near 60 are possible
where sun breaks out. With this, RH values are expected to
quickly drop, especially west of the Blue Ridge. Forecast
soundings would suggest that we could drop as low as 20 percent
in some spots. This could lead to elevated fire danger today,
and more can be found in the Fire Danger section below.

Remaining clouds should clear out this evening but another
shortwave will dive through the larger trough late tonight,
bringing a return of some clouds and a brief period of upslope
snow showers. Snow amounts should generally be less than one
inch. Overnight lows will be in the 30s for most of the area.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
The low will track toward the Canadian Maritimes on Friday as
high pressure simultaneously builds to our south. This will lead
to a strong pressure gradient and gusty northwesterly winds
across the area. Gusts will generally range from 30-45 mph,
highest in the mountains. While there is some potential for Wind
Advisories in the mountains, the strongest winds are near or
above the inversion height and there will be a lack of strong
pressure rises or cold advection. Any lingering clouds will
clear through the day, and high temperatures will range from the
upper 40s in the mountains to the lower to middle 60s across
Central Virginia.

Friday night should remain dry although with some increase in
clouds. A thermal gradient will begin to develop across the area
as warm advection begins ahead of a low pressure system in the
Great Lakes. This will result in lows in the mid 30s across
northeast Maryland to the lower to mid 40s across the central
Shenandoah Valley and central Virginia. This warm front will
remain draped across the area through Saturday as the low tracks
toward the Mid Atlantic. The track of this low and the warm
frontal position will have influence on high temperatures (50s
north/60s to near 70 south) as well as where the most rain
falls. The highest rain chances currently stretch across the
eastern West Virginia panhandle and northern Maryland. Clouds
may linger Saturday night along with some rain showers along the
Alleghenies. Lows will be in the 40s.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
A warm front lingering around the Ohio Valley and Mid-Atlantic
through the weekend will bring clouds and some shower activity.
Currently the greatest chance for precipitation on Sunday is along
the Alleghenies, expanding eastward from there with 20-30 PoPs but
generally remaining west of I-95 during the day.

Low pressure approaches from the west Monday into Tuesday, bringing
greater chances of rain for the start of the week. Guidance has
trended colder after the system exits Wed/Thurs, bringing possible
upslope snow along the Alleghenies to finish off the extended.

Temperatures will be well above normal Sunday with highs in the 60s
to 70s outside of the mountains, and closer to normal for the start
of the week (50s to 60s) as the next low pressure system moves
through. Behind the system will be near to slightly below normal.

&&

.AVIATION /14Z THURSDAY THROUGH MONDAY/...
There are a wide range of fluctuating ceilings across the area
this morning ranging from LIFR to VFR. However, sub-VFR ceilings
will likely remain through at least 12Z, then slowly clear from
west to east through early afternoon as drier air moves in
behind a cold front. Light to occasionally moderate rain will
continue at the metro terminals this morning before ending this
afternoon. Northwesterly winds may gust 20-25 kt this afternoon,
with at least some sporadic gusts lingering through the night.

VFR conditions expected Friday, but northwest winds will gust
25-35 kt through the day. Sub-VFR conditions along with light
rain are possible Saturday north of a warm front which will
waver near MRB and the metro areas.

Restrictions are possible Sunday into early next week with shower
activity from a weak front lingering in the region followed by a low
pressure system. Winds could be gusty on Sunday, up to around 20-25
kt out of the northwest. Monday will be less gusty with winds out of
the east/northeast.

&&

.MARINE...
A cold front will cross over the waters this morning, leading
to a wind shift to north-northwesterly winds. Small Craft
Advisories are in effect for all waters from late this morning
into tonight. Winds may approach gale force late tonight near
southern Maryland as low pressure passes off the coast, but
confidence is low. Likewise, winds will increase across all
waters Friday with gusts to at least 30 kt likely. However, will
leave the Gale Watch in effect for now since there is still some
uncertainty for widespread gale condtions.

At this time, sub-SCA conditions are most likely Friday night
into Saturday night.

Winds over portions of the waters may approach SCA criteria during
the day Sunday and Monday as a weak front and low pressure system
move through the area.

&&

.FIRE WEATHER...
For today, as a cold front pushes through the region, gusty
northwest winds are expected in its wake, especially this
afternoon into the evening. Forecast soundings are indicative of
a sharp decrease in RH in association with this, especially
those in the lee of southwest to northeast oriented ridges.
Generally, RH values will drop as low as 20 to 25 percent in
spots. This, paired with sustained winds of 10 to 15 mph and
frequently gusts up to 25 or 30 mph, has lead to and SPS for
fire danger today west of the Blue Ridge in WV and VA.

For Friday, there is a bit more uncertainty. While winds do
increase and there is the potential for very low RHs, the exact
location at this time is not certain. It is entirely possible
that the worst conditions could overlap with areas that have
seen substantial rain in recent days (east of the Blue Ridge and
especially along the I-95 corridor). Further evaluation is
needed, as well as coordination with fuel moisture experts to
determine the threat tomorrow. However winds are expected to be
very strong tomorrow, especially west of the Blue Ridge. The
main question there will be how low RH values get due to some
lingering cloudcover from overnight. A decision on that will be
made at a later time.

&&

.TIDES/COASTAL FLOODING...
Tides will remain elevated this morning, with Coastal Flood
Advisories in effect for the more sensitive locations. Winds to
turn north- northwesterly behind a cold front today. This
should lead to a reduction in anomalies and gradually lowering
water levels. Thereafter waters levels are expected to remain
below minor flood stage.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Coastal Flood Advisory until 1 PM EDT this afternoon for
     DCZ001.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 11 AM EDT Friday for ANZ530>533-535-
     536-538>542.
     Gale Watch from Friday morning through Friday afternoon for
     ANZ530>533-535-536-538>542.
     Small Craft Advisory until 4 AM EDT Friday for ANZ534-537-543.
     Gale Watch from late tonight through Friday afternoon for
     ANZ534-537-543.

&&

$$

SYNOPSIS...ADS
NEAR TERM...ADS/CJL
SHORT TERM...ADS
LONG TERM...CAS
AVIATION...ADS/CJL/CAS
MARINE...ADS/CJL/CAS
FIRE WEATHER...
TIDES/COASTAL FLOODING...


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