Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

828
FXUS61 KLWX 250809
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
409 AM EDT Fri Sep 25 2026

.WHAT HAS CHANGED...
Gale Warnings and Small Craft Advisories have been issued
through Saturday. Coastal Flood Advisories have been extended
through early Saturday morning for some locations. Patchy dense
river valley fog is occurring west of the Blue Ridge this
morning. Confidence is increasing on some rain moving inland
this weekend, and the potential track spread of the Nor`easter
seems to be narrowing.

&&

.KEY MESSAGES...
- 1) A Nor`easter brings below normal temperatures, breezy
  conditions, and possibly some rain at times through this
  weekend.

- 2) Patchy dense fog is possible along the river valleys west
  of the Blue Ridge Mountains this morning, with some frost
  possible in the higher elevation valleys.

- 3) Warm and calm conditions next week before rainfall chances
  return by late next week.

&&

.DISCUSSION...
KEY MESSAGE 1...A Nor`easter brings below normal temperatures,
breezy conditions, and possibly some rain at times through
this weekend.

A closed upper low stretches along the Mid Atlantic and Carolina
coasts this morning, with a strengthening low pressure center
east of Cape Hatteras. This Nor`easter will impact the area
through the weekend, as the northern stream wave pattern will
result in a blocking ridge building north of the closed low. 500
mb cluster analysis shows mainly subtle differences in the depth
and position of the upper low, but these small differences could
have notable impacts at the surface. With that said, both AI and
physics-based 00Z ensemble runs showed some consistency with the
surface low behavior... generally drifting northward and
strengthening through Saturday before drifting westward toward
the New Jersey coast, then becoming occluded and weakening
while drifting slowly northeastward early next week as a
shortwave trough in central Canada weakens the blocking ridge.

Sensible impacts will of course be greater with eastward extent
in the area. Below normal temperatures (highs in the upper 60s
to mid 70s) and gusty winds will continue for most of the area.
In a worst case scenario (stronger low closer to the coast),
locations near the Chesapeake Bay could need a Wind Advisory,
but currently gusts between 20 and 40 mph are expected,
strongest Saturday and possibly continuing Sunday. The cirrus
shield will hug mainly eastern portions of the area today, but
expect more extensive cloud cover Saturday and Sunday. The
current track forecast also has more guidance spreading some
rain into the area, particularly along the I-95 corridor, but
potentially as far west as the Potomac Highlands. This rain
could start as early as tonight but becomes more probable
Saturday and Sunday. At this time, heavier rain is expected to
remain east of the area. Coastal flooding, mostly minor in
nature, will also be an issue...see separate section below.

While rain chances and wind gusts will likely start declining by
Monday, cloud cover may remain stubbornly in place.


KEY MESSAGE 2...Patchy dense fog is possible along the river
valleys west of the Blue Ridge Mountains this morning, with
some frost possible in the higher elevation valleys.

Clear skies, calm winds, and temperatures dropping into lower
40s have resulted in fog forming along the river valleys west
of the Blue Ridge this morning. The valleys in the Potomac
Highlands are most filled in, but the immediate Shenandoah River
also has fairly continuous coverage. Some observations indicate
dense fog of a quarter mile or less, but it is unlikely it
becomes widespread enough to warrant an advisory.

A Frost Advisory continues until 9 AM for portions of the higher
Allegheny Mountains. Given current temperature trends, frost
will likely be limited to the most sheltered cold air sinks.

Both threats will quickly end after sunrise.


KEY MESSAGE 3...Warm and calm conditions next week before rainfall
chances return by late next week.

The Nor`easter near the area at the start of next week is going to
quickly weaken, then push offshore Monday into Tuesday. Brief high
pressure builds in behind the departing Nor`easter, with mostly dry
conditions to begin next week. A gradual warming trend is expected
as highs go from low to mid 70s on Monday to around 80F Wednesday
and Thursday. Mid-level ridging might develop across much of the
eastern CONUS at some point during the middle to late part of next
week. There`s still a lot of variance in the model guidance, but if
that were to happen we could see highs reach well into the 80s at
some point. A clipper passing by to our north  could bring a few
showers Wednesday. Otherwise, the next best chance for rain looks to
be at the end of next week when a stronger cold front approaches
from the west.

&&

.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
Patchy fog at CHO earlier seemed to be brief as there is now a
light wind. Some valley fog could also roll into MRB before
sunrise, although this remains somewhat uncertain.

Otherwise, VFR condtions are expected to continue through
tonight. The biggest impact to terminals will be gusty winds as
a slow moving Nor`easter drifts northward along the coast this
weekend. Gusty north/northeast winds are expected today, before
shifting to north/northwesterly on Saturday and Sunday. Each
afternoon, wind gusts between 15 and 25 knots are expected
across the terminals, with some gusts to 30 knots possible at
BWI, DCA, and MTN. There is increasing confidence in lower
ceilings and occasional rain Saturday into Sunday, particularly
at those same terminals. Rain chances and wind gusts will start
declining Monday, but sub-VFR ceilings may persist. Improving
conditions are more likely Tuesday as high pressure builds
toward the area.

&&

.MARINE...
Small Craft Advisories are in effect for all waters today,
although the wider portions of the bay near southern Maryland
could have some gusts that near gale force at times. Northerly
winds will gradually increase tonight into Saturday as a
Nor`easter strengthens off the coast. Gale Warnings go into
effect south of North Beach tonight, then expand to Sandy Point
and the adjacent estuaries Saturday. Small Craft Advisories were
extended elsewhere. Warnings were issued where confidence is
currently highest, but it`s possible they may need to be
extended for most of the Chesapeake Saturday. In a worst case
scenario (low stronger and closer to the coast), gusts could
approach storm force. Uncertainty increases Saturday night into
Sunday as the Nor`easter pivots near the New Jersey coast. At a
minimum, Small Craft Advisory conditions will continue, but gale
force winds remain possible, especially along the Chesapeake.

SCA conditions could continue over most of the waters through
Monday as the Nor`easter impacting the region finally weakens
and begins to push offshore. Sub-SCA winds return Monday night
through mid week.

&&

.TIDES/COASTAL FLOODING...
Coastal flooding will continue to be an issue through the
weekend due to a Nor`easter off the coast and high astronomical
tides. There has been a slight downward trend in water levels
this morning, so previous warnings were converted to
advisories.

The forecast gets very complicated tonight through Sunday as the
Nor`easter strengthens and potentially retrogrades westward
toward the area Sunday. Model guidance shows an extreme amount
of forecast spread with respect to tidal levels starting this
afternoon through the weekend. This uncertainty is tied to
the placement of the aforementioned coastal low, and whether
its associated wind field will allow water to be able to start
to drain out of the mouth of the Bay (or at least fully pushed
to the southern end of the bay). Advisories were extended
through early Saturday morning for the more southern locations,
but only through this evening at Annapolis due to some potential
for water starting to be shoved to the south. Points north of
Annapolis are much less likely to see flooding due to the steady
north wind.

Even with this decrease in water levels from the north, guidance
is indicating there could be a snapback at some point over the
weekend (likely the second half) which could reintroduce some
flooding with northward extent. Another round of locally
moderate flooding can`t be ruled out. While the Nor`easter will
pull away early next week, extended range guidance suggests
water levels will remain elevated.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Coastal Flood Advisory until 9 AM EDT this morning for DCZ001.
MD...Small Craft Advisory until 6 PM EDT Saturday for MDZ008.
     Coastal Flood Advisory until 9 PM EDT this evening for MDZ014.
     Coastal Flood Advisory until 7 AM EDT Saturday for MDZ016-018.
     Coastal Flood Advisory until 5 AM EDT Saturday for MDZ017.
     Frost Advisory until 9 AM EDT this morning for MDZ509-510.
VA...Coastal Flood Advisory until 7 AM EDT Saturday for VAZ057.
     Frost Advisory until 9 AM EDT this morning for VAZ503.
     Coastal Flood Advisory until 10 PM EDT this evening for VAZ054.
WV...Frost Advisory until 9 AM EDT this morning for WVZ501-505.
MARINE...Small Craft Advisory until 6 PM EDT Saturday for ANZ530-531-
     535-536-538-539.
     Small Craft Advisory until 6 AM EDT Saturday for ANZ532-
     540>542.
     Gale Warning from 6 AM to 6 PM EDT Saturday for ANZ532-540>542.
     Small Craft Advisory until 6 PM EDT this evening for ANZ533-
     534-537-543.
     Gale Warning from 6 PM this evening to 6 PM EDT Saturday for
     ANZ533-534-537-543.

&&

$$

DISCUSSION...ADS/KRR
AVIATION...ADS/KRR
MARINE...ADS/KRR