665
FXUS61 KLWX 231910
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
310 PM EDT Fri Oct 23 2026

.WHAT HAS CHANGED...
A Frost Advisory has been issued for portions of northern
Maryland late tonight into Saturday morning. The Small Craft
Advisory was cancelled, except for the middle Chesapeake and
lower tidal Potomac, where it was extended until 2 AM.

&&

.KEY MESSAGES...
- 1) Frost or freezing temperatures are possible in many areas
  tonight, Saturday night, and Sunday night.

- 2) Dry weather continues through next week along with
  generally seasonable temperatures.

&&

.DISCUSSION...
KEY MESSAGE 1...Frost or freezing temperatures are possible in
many areas tonight, Saturday night, and Sunday night.

With a large area of Canadian high pressure building overhead
through the weekend, conditions will likely become favorable
for radiational cooling (light to calm winds, mainly clear skies
and a cool background airmass). At the moment it is unclear
which night will be the coldest, although Saturday night will
have a slight advantage given the position of the high.

The growing season for 2026 has ended along and west of the Blue
Ridge and Catoctin Mountains, but continues east of there. Any
headlines for frost/freeze conditions will only be issued where
the growing season remains active.

For tonight, temperatures look to fall into the mid to upper 30s
for many areas (slightly colder west of the Blue Ridge and
slightly warmer in the urban areas and bayshore). The typically
colder spots of northern MD and the central VA piedmont could
at least briefly come close to freezing. For the afternoon
package, a Frost Advisory was only issued from Frederick to
Cecil Counties. These areas will be closer to the surface high
and have lower surface dew points. Farther to the south, there
will be a background easterly flow and perhaps some residual
clouds, so the evening shift will watch trends to determine if
the advisory needs to be expanded.

For Saturday night, more widespread cold (possible frost/freeze)
conditions are possible as high pressure settles more directly
overhead. This would bring the frost/freeze threat for most
areas outside the major urban centers and immediate shore of the
Chesapeake Bay. If the colder temperature guidance verifies,
then the growing season may end for more areas west I-95 come
early Sunday morning. The high will remain overhead through
Monday morning, and the low level airmass doesn`t change
appreciably, so frost/freeze conditions will be possible again
Sunday night.

Did not make appreciable changes to the previous min temperature
forecasts, which are near or below the coldest guidance which
performs best in radiational cooling (MOS, NBM 10 percentile and
Canadian Regional).


KEY MESSAGE 2...Dry weather continues through next week along
with generally seasonable temperatures.

Canadian high pressure will continue to prevail overhead over the
next several days as upper-level ridging builds in from the west. As
this ridging tracks east, a dry backdoor cold front will move
through Tuesday and into Wednesday, with winds shifting
northeasterly in the wake of the front. With PWATs remaining dry
through this period, no precipitation is anticipated as this front
moves through.

As this surface high pressure continues on, temperatures remain
seasonable, with highs in the 60s to low-70s. Overnight lows could
gradually increase somewhat throughout the week as this high
pressure persists, with skies remaining mostly clear throughout the
week. A few models hint at this high pressure breaking down towards
the end of next week as a weak trough begins to form over the Ohio
River Valley next Thursday. Regardless, expect continued dry &
seasonable conditions to continue at least through the next several
days as the current pattern remains largely unchanged.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
VFR conditions are expected to prevail through early next week.
There are some hints that a slight uptick in low-level moisture
could lead to some patchy fog during the early morning hours
through the weekend, though confidence in timing and extent of
sub-VFR is low at this time.

Light E to NE winds this afternoon will become light to calm
tonight. A more E to SE flow is likely Saturday, with light to
calm winds again Saturday night. Wind direction may be a bit
variable, ranging from SE to NE as high pressure passes directly
overhead Sunday.

VFR conditions are anticipated to continue across terminals
through Wednesday as conditions remain dry across the Mid-
Atlantic. Light westerly winds Monday shift northerly on
Tuesday, then east to southeasterly on Wednesday in the wake of
a backdoor cold front.

&&

.MARINE...
N to NE winds this afternoon will become more E to SE tonight
into Saturday. Winds have decreased below SCA levels this
afternoon, but are forecast to increase again by late afternoon
or early evening on the wider waters of the bay surrounding
southern Maryland. Thus, northern portions of the advisory have
been cancelled, but the lower Potomac to Tangier Sound have been
extended through 2 AM. While winds may increase elsewhere,
advisory level gusts look to be brief in duration if they occur.

High pressure will build overhead this weekend. Winds will vary
a bit from northeast to southeast, but at light speeds less than
10 knots. Winds stay below SCA criteria Monday. A dry backdoor
cold front passing through could briefly bring wind gusts near
SCA criteria on Tuesday before diminishing again overnight.
Westerly winds shift northerly Tuesday, then easterly Wednesday
in the wake of the front.

&&

.TIDES/COASTAL FLOODING...
Generally light but steady northeast to east winds are expected
to keep water levels elevated through the upcoming weekend.
When paired with high astronomical tides due to the upcoming
full moon on October 26, additional rounds of minor tidal
flooding are possible. There has been a slight trend downward,
so there is some decrease in confidence for which locations
reach minor flooding in forthcoming high tides. Guidance does
show a more notable decline in water levels by Monday when flow
finally turns westerly.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Frost Advisory from 1 AM to 9 AM EDT Saturday for MDZ004>006-
     008-507-508.
     Coastal Flood Advisory until 7 PM EDT this evening for MDZ014.
VA...None.
WV...None.
MARINE...Frost Advisory from 1 AM to 9 AM EDT Saturday for ANZ530.
     Small Craft Advisory until 2 AM EDT Saturday for ANZ534-537-
     543.

&&

$$

DISCUSSION...ADS/DHOF/SRT
AVIATION...ADS/DHOF/SRT
MARINE...ADS/DHOF/SRT

NWS LWX Office Area Forecast Discussion