FXUS61 KLWX 241529
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1029 AM EST Mon Feb 24 2025

.SYNOPSIS...
High pressure will gradually slide offshore today leading to
gradually warming temperatures and dry conditions. A weak cold front
will push through the region Tuesday with high pressure briefly
returning Wednesday. Widespread rain chances are expected Thursday
as a stronger cold front and area of low pressure cross the region.
Cooler temperatures return Friday with another frontal system
crossing the region this weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
MID-MORNING UPDATE...
Skies are mostly clear over the region this morning, with some
mid/high clouds to the northwest. Mid/high clouds are expected
to very gradually increase out of the northwest through the day,
but mostly sunny skies are expected through the afternoon. Ample
sunshine and southerly flow will allow temperatures to reach
into the upper 50s for much of the area, and possibly into the
low 60s in spots.

With southerly flow, channeling of the winds along the
Chesapeake Bay is possible this afternoon and into the evening,
resulting in locally stronger gusts 18-20kts, especially over
the wider waters. Latest hi-res guidance shows this over the
northern and central Bay as well, so have expanded the current
Small Craft to cover these areas.

Cloud cover increases overnight and above normal low
temperatures in the 30s to low 40s are expected.

PREVIOUS DISCUSSION FOLLOWS...
Ahead of the next frontal system currently over southwestern
Ontario, a warm advection regime will ensue across the area. The
steady period of low-level southerlies should help further
bolster temperatures. Recent deterministic guidance shows 850-mb
temperatures around 2C, which dry adiabatically mixed to the
surface would support upper 50s to low 60s. Based on yesterday's
highs exceeding the guidance, have opted to go a few degrees
above such guidance today. This favors widespread mid/upper 50s,
accompanied by some spotty 60 degree readings over the
Shenandoah Valley back into the Allegheny mountain valleys.
Given the amount of boundary layer mixing expected, some
southerly gusts up to 15 to 20 mph are possible. Skies should
remain mostly sunny through the day before clouds increase from
the northwest after dark.

Given the increase in clouds and warm advection regime, above
average temperatures are expected overnight. Forecast lows will
be in the mid/upper 30s.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
The upstream flow begins to amplify on Tuesday with the next
weather maker set to cross the area. High-resolution models
continue to favor a fairly moisture starved system with only
limited shower potential. Overall rain chances range from 15 to
25 percent (slightly higher along the Alleghenies), mainly
along and north of I-66. Total rainfall amounts will largely
range from a trace to 0.05". Despite the added clouds through
the day, winds shifting to westerly should help raise daytime
temperatures through downsloping effects. The current forecast
package calls for high temperatures in the upper 50s to low 60s,
with 40s to low 50s in the mountains. Any residual shot of rain
across northeastern Maryland winds down around dusk.
Northwesterly winds begin to diminish in strength overnight
along with less clouds away from the mountains. Forecast lows
will be in the low/mid 30s, locally around the upper 20s along
the Allegheny ridgetops.

The mid/upper pattern remains progressive as the initial trough
exits offshore. In the wake, brief height rises are expected as
a shortwave ridge passes through. Expect another day with above
average temperatures on Wednesday. Underneath mostly sunny
skies, highs are forecast to again push into the upper 50s to
low 60s (perhaps a couple mid 60s well south of I-66 in
Virginia). Clouds begin to increase by the evening and into the
night ahead of a wetter system set to arrive on Thursday. This
ultimately leads into a mild night on Wednesday with lows
holding steady in the low/mid 40s (around 15 degrees above
average).

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
Widespread rain chances return to the area Thursday as a strong cold
front crosses the region. Rain chances will increase from west to
east Thursday morning into Thursday afternoon. Some dry slotting
will likely occur in the lee of the Alleghenies Thursday evening
into Thursday night under post frontal (downsloping) west to
northwest flow. Precipitation chances will continue along the
western slopes of the Alleghenies and areas further east as the
trailing upper level trough kicks through. Once again precipitation
will mainly be in the form of rain although a brief period of
upslope snow showers are possible late Thursday night into Friday
morning along the western slopes of the Alleghenies as colder air
rushes in. Rainfall amounts for this event will remain light with
most locations seeing a tenth to four tenths of an inch of rainfall.
Heaviest rain will be confined to areas east of I-95 (i.e southern
MD and the northern neck of VA). High temperatures Thursday will
push into the mid to upper 50s and low 60s east of the Alleghenies
with overnight lows falling back into the 30s (20s over the
mountains).

Cooler weather returns with brief high pressure Friday. Rain showers
will exit east of the Chesapeake Bay with some leftover upslope snow
showers over the mountains. Skies will gradually clear with high
temperatures in the mid to upper 40s and low 50s (30s mountains).
Lows Friday night will fall back into the 30s with increasing clouds
as another frontal boundary approaches the area.

This front looks to cross the area Saturday afternoon and evening. A
few showers will accompany the boundary, but overall most locations
should remain dry outside the Alleghenies. This is due in part to
blocking high pressure over the southeastern U.S which will limit
any substantial moisture to push northward. Highs Saturday will push
back into the 50s and 60s (40s over the mountains). Lows Saturday
night will fall into the 20s and 30s. Broad high pressure dominates
the forecast Sunday into the early part of next week.

&&

.AVIATION /15Z MONDAY THROUGH FRIDAY/...
While high pressure slowly begins to retreat offshore, VFR
conditions are expected through tonight. Southerly winds may
increase to around 15 to perhaps 20 knots this afternoon before
decreasing after dark. By Tuesday, a weak system passing through
may bring a few showers with it, mainly north of I-66. Any
restrictions would be brief. Winds will mainly be out of the
west to northwesterly direction before returning to southerly on
Wednesday. VFR conditions are likely as this occurs, while the
next system looms upstream for Thursday.

Sub VFR conditions (MVFR to perhaps IFR conditions) return Thursday
into Thursday night as a strong cold front crosses the region. The
front will bring widespread rain chances to the terminals. Winds
will turn from the southwest Thursday to the northwest Thursday
night at 10 to 15 kts. Friday brings cool and blustery conditions
across the terminals under post frontal west to northwest flow.
Additional wind is expected this weekend as another front crosses
Saturday into Saturday night. Prevailing VFR conditions are expected
during this time.

&&

.MARINE...
Winds are very light, generally under 5 knots, early this
morning. As southerly winds increase through the day, some
channeling effects are possible over the wider waters of the
Chesapeake Bay. Winds around Small Craft Advisory levels
(18-20 kts) are expected from 1 PM this afternoon to around
1 AM. Winds diminish in strength on Tuesday into much of
Wednesday. However, after a day or so of west- northwesterlies,
southerly channeling may yield another shot for Small Craft
Advisories by late Wednesday.

SCA conditions return late Thursday into Friday in the wake of a
strong cold frontal boundary. Winds will switch from the southwest
to the west and northwest Friday with gusts up to 20kts. Additional
SCAs may be needed Saturday as another cold front crosses the
waters.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 11 PM EST this evening for
     ANZ531>533.
     Small Craft Advisory from 3 PM this afternoon to 1 AM EST
     Tuesday for ANZ534.

&&

$$

SYNOPSIS...EST
NEAR TERM...BRO/CAS
SHORT TERM...BRO
LONG TERM...EST
AVIATION...BRO/EST
MARINE...BRO/EST/CAS