722
FXUS61 KLWX 050134
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
934 PM EDT Fri Oct 4 2024

.SYNOPSIS...
A weak cold front will move through the area tonight. High
pressure will build across the area Saturday and Sunday. A
stronger cold front approaches the area late Sunday night into
Monday. This front will deliver below average temperatures and
dry conditions as Canadian high pressure settles in for the
middle part of next week.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
The cold front appears to be pushing through the I-81 corridor
this evening. Only one small shower remains on radar, so may be
able to scale back PoPs even though some guidance carries the
risk for an isolated shower through southern Maryland, ending by
1 or 2 AM.

The fog forecast is tricky tonight. Guidance is most supportive
of fog and low clouds east of the Blue Ridge, although
persistent cloud cover could limit the potential for widespread
dense fog. Guidance also suggests any fog may be somewhat
transient as a push of northwest winds arrives behind the front
toward dawn. Skies will be clearer west of the Blue Ridge, so
valley fog seems more plausible despite forecast guidance since
winds will be fairly light. Perhaps dry advection behind the
front will be a limiting factor.

Low temperatures will be in the upper 40s to lower 50s west of
the Blue Ridge and upper 50s to lower 60s to the east.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
Improving weather conditions are expected Saturday with upper level
ridging aloft and surface high pressure building over the eastern
Great Lakes region. Outside of some clouds and fog Saturday morning,
sunny skies will prevail with light north to northwesterly flow.
Highs Saturday will push into the mid to upper 70s (with upper 60s
and low 70s in the mountains). Overnight lows will fall back into
the 50s and 60s.

High pressure shifts toward New England Saturday night before
pushing offshore Sunday. Mostly sunny skies are expected for much of
the day with clouds increasing late as another shortwave disturbance
and front approach the region. Expect a warm front to lift through
SUnday morning followed by the cold front Sunday night into Monday
morning. A few showers and perhaps an isolated thunderstorm will
accompany the boundary as it passes through.The greatest coverage of
any showers or storms should be across the northern half of the
forecast area, closer to the upper trough passing by to our north.
Highs Sunday will push into the mid to upper 70s (with upper 60s and
low 70s in the mountains). Lows Sunday night will range from the
upper 40s in the mountains, to the lower 60s along/southeast of
I-95.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
On Monday, a secondary front pushes through the region as troughing
sets up to our northeast. Monday will be a few degrees cooler for
sure, and the air mass will be much drier in nature. There will also
likely be a brief, albeit slight, uptick in winds post-front, but it
isn`t anything that looks hazardous at this point.

We will really start to see a noticeable air mass change on Tuesday
as the cooler air behind this secondary front pushes into the
region. We will see fall-like temperatures with highs in the mid to
upper 60s and dew points well into the 40s. This will continue
through Thursday.

&&

.AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
A weak cold front will slowly push across the area tonight.
Various cloud decks persist across the area (including MVFR near
CHO), making tonight`s fog forecast tricky. Guidance is most
supportive of fog and low clouds east of the Blue Ridge,
although persistent cloud cover could limit the potential for
widespread dense fog. Guidance also suggests any fog may be
somewhat transient as a push of northwest winds arrives behind
the front toward dawn. Skies will be clearer west of the Blue
Ridge, so valley fog seems more plausible despite forecast
guidance since winds will be fairly light. Perhaps dry advection
behind the front will be a limiting factor. At all TAF sites,
there is still a range of possibilities between LIFR and VFR.
For the 00Z TAFs, trended the forecast down slightly for the
metro area but not as low as recent LAMP runs.

High pressure returns this weekend with prevailing VFR
conditions returning at at all TAF terminals by mid Saturday
morning. Outside of the morning low clouds and fog (which may
remain away from the TAF sites), no hazards are expected. Winds
will be light out of the north on Saturday, and then light out
of the south on Sunday.

VFR conditions are expected on Monday and Tuesday in the wake of a
cold front. Gusty winds behind the front on Monday could reach 15 to
20 kts.

&&

.MARINE...
A few gusts to around 18 kt have been observed this evening in
southerly channeling along the Chesapeake. A weak cold front
will cross the waters tonight shifting the winds toward the
north. A brief period of gusts may approach advisory criteria
Saturday morning. North to northeast winds continue through
Saturday night before turning back to the south Sunday into
Sunday night ahead of the next cold frontal boundary. Some
channeling is also possible Sunday afternoon and evening leading
to a brief period of near SCA conditions especially over the
open waters of the bay/tidal Potomac.

SCAs are possible on Monday afternoon in gusty NW flow in the wake
of the cold front. Winds will gradually taper off through Tuesday,
with SCAs becoming less likely.

&&

.TIDES/COASTAL FLOODING...
Tidal anomalies have steadily decreased today as lighter winds have
allowed water to flow down and out of the Chesapeake Bay and Tidal
Potomac River. These anomalies should remain low enough to prevent
most sites from reaching Minor flood through the weekend
(advisories for DC and Alexandria end at midnight tonight).
Southerly flow on Sunday may bring a return to minor flooding at
some locations. A strong cold front moves across the area
Sunday night, with offshore flow early next week expected to end
the prolonged period of elevated tides in the area.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Coastal Flood Advisory until midnight EDT tonight for DCZ001.
MD...None.
VA...Coastal Flood Advisory until midnight EDT tonight for VAZ054.
WV...None.
MARINE...None.

&&

$$

SYNOPSIS...EST
NEAR TERM...ADS
SHORT TERM...EST
LONG TERM...CJL
AVIATION...ADS/CJL/EST
MARINE...ADS/CJL/EST
TIDES/COASTAL FLOODING...LWX