Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

639
FXUS61 KLWX 110059
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
859 PM EDT Sat Oct 10 2026

.WHAT HAS CHANGED...
A Flood Watch remains in effect for Sunday from the Blue Ridge
eastward to just west of the D.C. metro area. Global ensemble
guidance showed a decrease in rainfall probabilities further
east so held off on eastward expansion of the flood watch. No
significant changes were made to the forecast.

&&

.KEY MESSAGES...
- 1) Remnants of Post-Tropical Cyclone Isaias to bring rain,
  breezy to windy conditions, and the threat of tornadoes
  Sunday.

- 2) Above normal temperatures Tuesday will fall the second
  half of the week as moisture starved fronts move through.

&&

.DISCUSSION...
KEY MESSAGE 1...Remnants of Post-Tropical Cyclone Isaias to
bring rain, breezy to windy conditions, and the threat of
tornadoes Sunday.

Post-Tropical Cyclone Isaias continues to lift northward across
Georgia and Alabama. This system has weakened considerably after
last evening`s landfall while losing all tropical
characteristics. The associated mid-level circulation
strengthens and becomes a large cutoff low later tonight. To the
east, surface high pressure over the northeastern U.S. today
moves offshore off southern New England tonight.

In advance of this broad area of low pressure, a thick high
cirrus shield continues to expand north and east into the Great
Lakes and New England. While this system still looms well to the
southwest of the area, some light scattered showers continue to
lift across I-64 toward the I-66 corridor. However, any amounts
are very light with some radar returns not even reaching the
ground. The thick cloud cover will hold temperatures mainly in
the upper 60s to low 70s this afternoon.

Looking ahead, the interaction of Isaias` remnants to the west
and surface high to the east will create a large area of
convergence / broad frontal zone over the Mid-Atlantic. There is
good model agreement that rain steadily moves from south to
north this evening into tonight as forcing for ascent increases
with some mid-level height falls in response to the approaching
cutoff low. It will take a bit of time for the surface to truly
saturate, so any rainfall this afternoon to evening across
central Virginia will struggle to amount to much. Eventually,
tropical moisture with PWATs at or above 2" surges in after
midnight.

It is worth mentioning again that conditions are favorable for a
widespread soaking rain, and 12Z and 00Z models have responded
with more QPF across the region. Forcing for ascent increases
tonight, and especially Sunday morning into Sunday afternoon as
mid-level heights fall with the approach of the cutoff low.
Enhanced low-level convergence and moisture transport will peak
Sunday morning into early Sunday afternoon. Strengthening
easterly flow into the Blue Ridge could also produce enhanced
rain amounts due to orographic effects. As a result, forecast
rain amounts have increased to 2.0-3.0", with locally higher
amounts of 3-5" possible. With this uptick, Flood Watches were
issued across the Blue Ridge eastward into the central Virginia
Piedmont region. This is in effect on Sunday 5 AM until Monday 2
AM. Some eastward expansion may be necessary if models trends
hold on or show further upticks.

Another noticeable trend in recent guidance is the higher
probabilities for severe weather Sunday afternoon. The main
synoptically forced rain moves north of the area early Sunday
afternoon. Rapid height falls and increasing low-level winds
provide a few hour window where some breaks in the clouds area
possible, leading to pockets of instability. A surface wave of
low pressure moves right through the area Sunday afternoon.
Forecast soundings indicate large, cyclonic hodographs, with
ample shear in place to support organized severe convection.
Clusters of thunderstorms develop along the leading edge of the
surface low pressure, with tornadoes and damaging wind gusts as
the main threats (looks mostly to be east of the Blue Ridge).
The NAM12, RRFS, and 12Z HRRR all show this scenario. The big
question still remains how much instability actually develops.
SPC has maintained a Slight Risk for Sunday, with a recent northward
expansion to just south of I-66 in Virginia.

The strong mid-level circulation is going to bring windy conditions
to the Alleghenies and Blue Ridge, starting late tonight into Sunday
morning. Wind Advisories were issued for downsloping easterly
winds in the Alleghenies (western Garrett, western Grant, and
western Pendleton Counties), and the Blue Ridge. The current
forecast for peak wind gusts is 40-50 mph in the
Alleghenies/Blue Ridge and 20-30 mph elsewhere.

The remnants of Isaias push offshore Monday, bringing an end to any
lingering showers. While conditions return humid and warm Monday,
there likely will not be much in the way of shower activity due
to subsidence behind the departing trough.


KEY MESSAGE 2...Above normal temperatures Tuesday will fall the
second half of the week as moisture starved fronts move through.

Brief ridging in the wake of the tropical remnants may bring high
temperatures Tuesday to near 80 degrees. Low pressure passing north
of the area will send a cold front southward Tuesday night. Most of
the rain likely remains across Pennsylvania, although some showers
may sneak southward. Showers will also be possible along the
Allegheny Front. There`s still some significant model spread on the
progression of this front during the middle of the week, with a
large spread of temperatures possible on Wednesday. However, the
general trend will be downward for the second half of the week. A
wave of low pressure or cold front may approach toward the end of
the week which could bring some rain, but model spread remains high
on the details.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
VFR conditions prevail through this evening, then conditions
deteriorate tonight into Sunday as the remnants of Post-
Tropical Cyclone Isaias impact the region. IFR conditions are
likely to overspread all terminals late tonight through Sunday
afternoon, as periods of rain and gusty winds cross the region.
There could be a few hour period of thunderstorms Sunday
afternoon, some of which could be severe, though this threat is
greatest east of the Blue Ridge. Have introduced the potential
for thunderstorms as a PROB30 group at KDCA, KIAD, and KBWI.
Conditions improve Monday morning, with the return of VFR
conditions. Northwest winds gusting around 20-25 knots possible
Monday afternoon. Winds eventually return to southerly by
Tuesday ahead of the next system.

Prevailing VFR conditions are anticipated from Tuesday through
Thursday. A passing cold front could bring some showers and
reduced CIGs Thursday night into Friday. Southwesterly winds
shift northerly by Thursday morning, then flow easterly later
Thursday evening.

&&

.MARINE...
Marine conditions are expected to deteriorate tonight through Sunday
night as the remnants of Post-Tropical Cyclone Isaias move
across the Mid-Atlantic. SCA conditions develop this evening in
the central Chesapeake Bay, then across all the waters tonight.
The strongest winds, gusts around 30 to 35 knots, will occur
Sunday morning. In particular, the uptick is most pronounced
over the more southern waters where Gale Warnings have been
introduced from 5 AM until 11 AM Sunday. Special Marine
Warnings may be needed Sunday afternoon for thunderstorms
capable of producing strong wind gusts and waterspouts. The
remnants of Isaias move offshore Monday morning, but SCA
conditions continue through Monday evening due to gusty
northwest winds in its wake.

Winds could fluctuate in & out of SCA criteria between Wednesday and
Thursday as a cold front passes through. Southerly winds shift
northerly by Thursday morning, then flow easterly later Thursday
evening.

&&

.TIDES/COASTAL FLOODING...
Widespread tidal flooding is likely during the Sunday afternoon to
evening high tide cycle. Several conditions are coming together to
produce a surge of water up the Chesapeake Bay and Potomac River.
Strong onshore winds coming during the highest of the daily tides,
which happens to coincide with the New Moon are going to produce
minor tidal flooding at most forecast locations. A Coastal Flood
Watch continues for Annapolis where Moderate tidal flooding is
possible. Water levels quickly decrease Monday morning as
offshore winds follow.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory from 1 AM to 11 PM EDT Sunday for MDZ008.
     Coastal Flood Watch from Sunday afternoon through Sunday
     evening for MDZ014.
     Wind Advisory until 11 AM EDT Sunday for MDZ509.
VA...Flood Watch from 5 AM EDT Sunday through late Sunday night for
     VAZ036>040-050-051-501-502-507-508.
     Wind Advisory from 2 AM to 11 AM EDT Sunday for VAZ507-508.
WV...Wind Advisory until 11 AM EDT Sunday for WVZ501-505.
MARINE...Small Craft Advisory from 1 AM to 11 PM EDT Sunday for ANZ530-
     535-536-538>542.
     Small Craft Advisory until 11 PM EDT Sunday for ANZ531>533.
     Small Craft Advisory until 5 AM EDT Sunday for ANZ534-537-543.
     Small Craft Advisory from 11 AM to 11 PM EDT Sunday for ANZ534-
     537-543.
     Gale Warning from 5 AM to 11 AM EDT Sunday for ANZ534-537-543.

&&

$$

DISCUSSION...AVS/BRO/KRR/SRT
AVIATION...BRO/KRR/SRT
MARINE...BRO/KRR/SRT