762
FXUS61 KLWX 111944
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
344 PM EDT Sun Oct 11 2026

.WHAT HAS CHANGED...
Have continued to lower temperatures today given the influence
of low clouds and persistent east to northeasterly winds on the
area. This would also shift the focus of any low-topped tornado
threat down toward I-64 where conditions should be slightly
warmer. However, instability continues to the main question
despite all of the low-level wind shear in place. Otherwise,
have added another Coastal Flood Advisory for the City of
Alexandria for the high tide late this evening.

&&

.KEY MESSAGES...
- 1) Remnants of Isaias bring rain, breezy conditions, and an
  isolated brief ornado or two.

- 2) Above normal temperatures through mid week, then a late-
  week cold front bring a drop in temperatures along with
  additional precipitation chances.

&&

.DISCUSSION...
KEY MESSAGE 1...Remnants of Isaias bring rain, breezy conditions,
and an isolated brief tornado or two.

A modified tropical air mass remains entrenched over the area
with widespread precipitatable water values ranging from 1.50 to
2.00 inches. The associated warm conveyor belt has brought
highly efficient rainfall to the region with a widespread 1.50
to 2.50 inches of rain observed during the past 18 hours. This
includes some pockets of 3 inch plus amounts where topography
has locally augmented the activity. As of 19Z/3 PM, a bulk of
these moderate intensity rains have moved north of I-66 and
continue edging toward the Mason-Dixon Line. Off the south, the
radar presentation suggests a mixture of scattered light showers
or drizzle. However, this lull is expected to be somewhat brief
in nature ahead of the main surface circulation which arrives an
hour or two before dusk.

Looking through the latest 12Z high-resolution models, there
continues to be a signal of heavier rainfall accompanying the
remnant circulation of Isaias. There appears to be some sort of
comma-head feature that contains enhanced lift and moisture
convergence. Unlike earlier rainfall elements, this could be a
bit slower moving and more focused. 3-hour totals could push
into the 1 to 2 inch range where this deformation-like band of
rainfall forms. The focus seems to be somewhere across the
central Virginia Blue Ridge into the adjacent Piedmont region.
As such, have opted to maintain the Flood Watch despite the
multi-hour lull in between the two rounds.

While a non-zero threat for low-topped tornadoes exists, the
overall probabilities have decreased given the stable air mass
in place. The Storm Prediction Center shifted the Slight Risk to
near I-64 and points southward, with a Marginal Risk extending
up to the Mason-Dixon Line. Although low-level shear is nearly
off the charts, the general lack of instability will make for a
tougher thermodynamic environment to work with. If any
instability did materialize, it certainly would not take much
for a quick spin up to occur late afternoon into the evening.

The entire complex of showers will continue to march eastward
into the overnight hours. This is largely tied to the upper low
currently swirling back over eastern Kentucky. Until this fully
clears the region, expect continued low stratus and shower
chances, along with breezy east/northeasterly winds and
temperatures in the 60s. Any chance for sunshine largely will
wait until midday Monday/Columbus Day.


KEY MESSAGE 2...Above normal temperatures through mid week,
then a late-week cold front bring a drop in temperatures along
with additional precipitation chances.

After an active finish to the weekend, subsequent days will
likely provide a warming trend along with more sunshine. In
particular, Tuesday and Wednesday carry the potential for a
return to the low 80s. There are even hints that some mid 80s
are possible which seems reasonable as 850-mb temperatures may
rise to around 16 to 18C. This is all in response to the
building of heights in the wake of the offshore passage of
Isaias.

Upper-level ridging will start to transition into zonal flow
Wednesday ahead of an incoming dry cold front, which will cause
temperatures to drop on Thursday. However, conditions still remain
generally mild during this time with highs in the low-to-mid 70s
through Friday. While a few rain showers are possible Thursday and
into Friday, dry air ahead of and behind the front likely limit
overall spread & duration.

Looking towards the end of the week, a deep upper-level Canadian
trough will traverse the Great Lakes before moving through the East
Coast. Model guidance varies significantly on timing and impacts of
this system. The ECMWF & related ensembles currently has the low
passing just north of the Mid-Atlantic late Friday and into
Saturday, whereas the GFS/GEFS shows a much deeper digging trough
moving through the Mid-Atlantic throughout the weekend, with a sharp
drop in temperatures following it. Given this uncertainty, the
outlook for the upcoming weekend remains largely uncertain regarding
any precipitation, although a general cooling trend can likely be
expected as the low passes through.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
As the remnants of Isaias continue to work their way through the
region, IFR ceilings will remain commonplace in this environment.
This also comes with periods of visibility reductions as rain
passes through the area. Any thunderstorm chances are likely
confined to the D.C. terminals as well as KCHO. With some
elevated instability, a few random lightning strikes have
occurred west of U.S. 15 in Virginia. Given this environment,
will maintain PROB30 groups at the mentioned terminals above
into the early evening hours. Low ceilings continue overnight
and could even lower to LIFR. Any improvements will likely need
to await until the early/mid morning hours on Monday.

For the second half of Monday, winds shift to northwesterly and
turn a bit breezier in nature. Afternoon gusts up to 20 knots or
so are expected, but with VFR conditions. A dry pattern continues
through at least mid-week with mainly south to southwesterly winds
likely.

Prevailing VFR conditions are anticipated from Tuesday through
Thursday, with southwest winds shifting northerly Thursday morning.
Rain showers could potentially bring brief periods of sub-VFR
conditions Thursday night into Friday as a cold front passes
through. Winds gust up to 20-25 knots on Friday in the wake of the
front, shifting back to southwesterly by Friday afternoon.

&&

.MARINE...
Although the east to southeasterly winds have somewhat abated
across much of the marine waters, expect another ramp up heading
into the evening/overnight period. This is in response to the
remnant circulation of Isaias which leads to another surge of
the wind fields. Given large amounts of low-level wind shear, a
brief waterspout is certainly possible late this afternoon into
the evening, especially across the more southern waters.

Behind a cold front, Small Craft Advisories may be needed for
much of Monday as northwesterly gusts up to 20 knots overspread
the waters. This largely falls off into the night before winds
shift to southerly by Tuesday. Some southerly channeling effects
may require additional advisories, but this may be somewhat
close to criteria.

Winds could fluctuate in & out of SCA criteria between
Wednesday and Thursday as a cold front passes through. A potent
upper-level trough will bring winds up on Friday, potentially
approaching gale conditions should current guidance persist.
Westerly winds shift northerly Thursday morning, then southerly
on Friday as the low passes through.

&&

.TIDES/COASTAL FLOODING...
Increasing onshore winds and elevated tide levels due to the New
Moon will result in coastal flooding during the high tide this
afternoon to evening. Coastal Flood Advisories have been issued
for a number of locations. At this point, Annapolis should see
water levels fall short of Moderate flood stage. Water levels
quickly decrease Monday morning as offshore winds follow. By
Tuesday, some snap back is possible as winds shift to southerly
which would bring a few locations back into Action stage.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory until 11 PM EDT this evening for MDZ008.
     Coastal Flood Advisory until 11 PM EDT this evening for MDZ014.
     Coastal Flood Advisory until 6 PM EDT this evening for MDZ016.
VA...Coastal Flood Advisory until 6 PM EDT this evening for VAZ057.
     Flood Watch until 2 AM EDT Monday for VAZ036>040-050-051-501-
     502-507-508.
     Coastal Flood Advisory from 7 PM to 11 PM EDT this evening for
     VAZ054.
WV...None.
MARINE...Small Craft Advisory until 11 PM EDT this evening for
     ANZ530>543.

&&

$$

DISCUSSION...BRO/SRT
AVIATION...BRO/SRT
MARINE...BRO/SRT

NWS LWX Office Area Forecast Discussion