794
FXUS61 KLWX 210755
AFDLWX
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
355 AM EDT Tue Apr 21 2026
.WHAT HAS CHANGED...
No significant changes to the forecast. Freeze Warnings remain
in effect for most of the region outside of the Alleghenies
through mid-morning this morning. Additional light rain chances
and warming temps mid to late week.
&&
.KEY MESSAGES...
1) Widespread freeze this morning as high pressure builds over
the region.
2) Warming temperatures mid to late week with additional rain
chances possible this weekend.
&&
.DISCUSSION...
KEY MESSAGE 1...Widespread freeze this morning as high pressure
builds over the region.
High pressure building over the region will result in light to
calm winds and great radiational cooling. Thus, a widespread
freeze will continue into the middle of this morning. Some
frost may also be noted, but given some elevated wind and ample
dry air in place, the threat may be limited.
For context, this is ~10 days past the median date of the last
spring freeze based on 1991-2020 climatology for areas along/east of
I-81. Given the warmth early this spring, many areas are ahead of
schedule from a growth stand point, so this freeze could be
rather impactful.
There are no frost/freeze headlines for the Alleghenies as the
growing season has not started there yet.
KEY MESSAGE 2...Warming temperatures mid to late week with
additional rain chances possible this weekend.
As Canadian high pressure slides off toward the south, a quick
moving cold front will cross the region by mid-week (late Tuesday
night into Wednesday). There will not be a whole lot of moisture to
work with, so any rainfall amounts are likely to be meager in nature
(less than a 0.10"). Some instability in the atmosphere could
produce a few thunderstorms, particularly during the afternoon
hours. A lack of stronger forcing, shear, or instability should lead
to generally weak convection, though some spotty downpours, gusty
winds, and small hail can`t be ruled out.
After a chilly start to the work week, ensembles agree on a
warm up through the middle to latter portions of the week. High
temperatures could push back into the low/mid 80s by Friday
ahead of another system likely to bring a return of rain by the
second half of Friday. A threat of showers continues through
much of the weekend before the frontal system exits east of the
region by late in the weekend. On Sunday, the latest forecast
package calls for highs returning to the 60s. This eventually
all lends itself to a cooler finish to the month of April.
However, there is uncertainty in the evolution of low pressure
approaching the area by then, and just how the temperature and
precipitation forecast pans out. The good news is that rain chances
are back in the forecast given the expanding drought and elevated
fire weather concerns across the region.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
High pressure building overhead will result in widespread
frost/freeze early this morning across all terminals. VFR
conditions continue through Friday. Some temporary sub- VFR
conditions are possible with a weak cold front Wednesday. The
front could bring brief -SHRA/-TSRA at the terminals Wednesday
morning into Wednesday afternoon. Locations down around KCHO may
see nothing at all. Winds shift to the south today at less than
15 kts with southwest winds ahead of the front Wednesday
switching back to the northwest Wednesday afternoon. Gusts
Wednesday will remain between 10 to 20 kts. Some LLWS also
possible west of the corridor tonight as southerly flow
increases ahead of the boundary.
Additional WAA showers are possible by Friday afternoon which
could be accompanied by a few restrictions. Initial winds will
be out of the NW on Thursday before becoming mainly westerly on
Friday. A shift to southeasterly is possible by Friday night.
More shower chances with temporary sub-VFR reductions are
possible this weekend.
&&
.MARINE...
High pressure builds overhead today. Winds become more southerly
through the day today with additional SCAs possible into
Wednesday due to southerly channeling. Sub- SCA level winds are
expected late Wednesday with winds out of the SW to NW as a
cold front crosses. This front may bring a few showers and
thunderstorms mainly Wednesday afternoon.
Expect sub-advisory level winds for both Thursday and Friday.
Weak gradients will favor multiple wind shifts before turning
mainly S/SE by Friday night.
SCA conditions return for portions of the waters this weekend.
&&
.FIRE WEATHER...
Much cooler temperatures are expected today with a moderating
trend in temperatures expected during the middle and second half
of the week. Winds will be on light side, but humidities will
be marginally low to near critical levels. The next potential
for rainfall is Wednesday into Thursday (mainly north of
I-66/US-50), but amounts look light.
Special Weather Statements may be needed for portions of the
Shenandoah Valley and central VA Piedmont this afternoon.
Elsewhere, winds should remain light enough to reduce fire
weather concerns.
&&
.TIDES/COASTAL FLOODING...
Southerly flow is expected today and tonight. This will result
in rising tidal anomalies. The higher members of P-ETSS and
SFAS, as well as STOFS and CBOFS all hint at the potential for
minor flooding at Annapolis early Wednesday as a result.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Freeze Warning until 10 AM EDT this morning for DCZ001.
MD...Freeze Warning until 10 AM EDT this morning for MDZ003>006-008-
011-013-014-016>018-503>508.
VA...Freeze Warning until 10 AM EDT this morning for VAZ025>031-
036>040-050-051-053>057-501-502-505>508-526-527.
WV...Freeze Warning until 10 AM EDT this morning for WVZ051>053.
MARINE...Freeze Warning until 10 AM EDT this morning for ANZ530.
Small Craft Advisory until 4 AM EDT early this morning for
ANZ531>534-537>541-543.
Small Craft Advisory from 8 PM this evening to 8 AM EDT
Wednesday for ANZ532>534-537-540>543.
&&
$$
DISCUSSION...KLW/DHOF/KJP
AVIATION...KLW/DHOF/KJP/EST
MARINE...KLW/DHOF/KJP/EST
NWS LWX Office Area Forecast Discussion