Chillum, Maryland 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

083
FXUS61 KLWX 200815
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
315 AM EST Sat Dec 20 2025

.SYNOPSIS...
High pressure will build across the area today. A dry cold front
will move through Sunday morning. High pressure will briefly
move overhead Monday. A low pressure system moving through the
Great Lakes may will affect the area late Monday night into
Tuesday. Another transient area of high pressure on Wednesday
may give way to a warm front on Thursday.

&&

.NEAR TERM /THROUGH TONIGHT/...
The center of high pressure is already moving into the upper
Ohio Valley, and outside the higher elevations, winds have
become light to calm. Temperatures will start the day in the 20s
and lower 30s, with teens in the higher elevations.

A progressive zonal flow aloft will bring the high quickly
across the area today, with southerly winds developing by
midday. Some mid and high level clouds are possible in
association with a jet streak aloft. With stronger warm
advection from the southwest, the warmest spots (possibly into
the lower 50s) will likely be the central Shenandoah Valley and
lower elevations of the Potomac Highlands. Most areas will have
highs in the upper 30s and 40s.

The southwest continues to increase aloft tonight as a trough
moves through the Great Lakes and Ohio Valley (with surface low
pressure well north in Ontario). While the low level jet will
result in gusty winds in the higher terrain, they should remain
below wind advisory criteria. Lows will be milder in the 30s.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
The system to the north will push a cold front through on
Sunday morning. With most of the forcing and moisture to the
north, only an increase in cloud cover is expected (and even
that is trending to transient mid and high level variety).
There will also be gusty westerly post-frontal winds which peak
in the 20-30 mph range (a bit higher along the ridges). Daytime
temperatures will remain mild in the mid 40s to mid 50s, but
temperatures will drop into the 20s, with upper teens in
spots, Sunday night due to the post-frontal cold and dry
advection.

The progressive pattern continues Monday, as surface high
pressure will already be overhead in the morning. Mid and high
level clouds increase through the day between jet dynamics and
warm advection aloft. Enough of a thermal trough lags that highs
will be a bit below normal in the upper 30s to mid 40s.

A flatter shortwave trough and relatively weak wave of low
pressure will move toward the Great Lakes Monday night. There
is some potential for an arm of light warm advection
precipitation to spread into the area, especially during the
second half of the night. Surface temperatures may be on either
side of the freezing mark, depending on how quickly cloud cover
increases and how much southerly flow is realized at the
surface. On top of that, thermal profiles aloft are also
uncertain, although generally warming with time. Thus there
could be some potential for freezing rain anywhere low level
cold air remains trapped. Should any snow occur on the front
end, the most probable place for that to occur would be mainly
north and east of Washington DC. With all that said, many areas
may just see rain should precipitation occur at all.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
Some light wintry precipitation may occur in parts of the
region early Tuesday. Precipitation amounts should be light but
we will have to see how temperatures are when precipitation
occurs in case we are looking at slippery places due to wintry
precipitation. The associated cold front will push through
Tuesday afternoon, with any lingering rain chances along the
Allegheny Mountains. High pressure will build overhead by
Wednesday morning. Temperatures will likely remain above normal
both Tuesday and Wednesday as ridging expands across the
southeast.

The cold front that dropped to our south midday Tuesday is expected
to lift northward as a warm front Wednesday night or Thursday.
This warm front could bring some precipitation across our region
Wednesday through Thursday. The precipitation, at this time,
appears to be light in intensity and could be mainly light rain.
Temperatures will be on the increase as well with the warm
front working its way northward. Temperatures could be almost 10
degrees above average on Thursday. Highs middle 40s to middle
50s. Temperatures will be even warmer on Friday with
temperatures reaching the upper 50s to lower 60s, although
ensemble spread does increase by this time.

&&

.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
High pressure builds in today, supporting VFR conditions. Winds
may be somewhat variable in direction early this morning before
they more decidedly swing to the south by mid morning. A few
gusts between 15-20 kt could occur during the afternoon and
evening, with some uncertainty about how much winds decrease
after sunset. That will be important for possible low level
wind shear development. The forecast low level jet has trended
slightly weaker and more transient compared to yesterday`s
forecast. However, it will peak around 40-45 kt around 1500 ft
with some potential for a low level inversion and slight
veering. This threat will likely end at some point in the second
half of the night.

VFR conditions continue through Sunday, although a dry cold
front will shift winds to the west with gusts up to 25 kt
possible through the afternoon. Another transient area of high
pressure will shift winds back to the south by Monday afternoon
with continued VFR conditions. A warm front may bring some light
precipitation late Monday night, though it is uncertain if
flight categories will be reduced. There is a small chance of
wintry precipitation in the area, but appears less likely at
the TAF sites.

VFR conditions for the most part through mid week. Some patchy
light rain Tuesday morning could lower conditions to MVFR at
times. Otherwise, VFR conditions through Wednesday night. Winds
southwest 5 to 10 knots Tuesday. Winds becoming northwest
Tuesday night through Wednesday 5 to 10 knots.

&&

.MARINE...
North to northwest winds are quickly diminishing this morning as
high pressure approaches. Any lingering Small Craft Advisory
conditions should be ending by 6 AM if not sooner. Winds will
quickly turn southerly by midday, increasing toward evening.
Small Craft Advisories will be issued for tonight for the
Chesapeake Bay. There may be a brief lull Sunday morning, but
then a cold front will cross and shift winds to the west and
northwest. Advisories are likely for all waters, with gusts
mostly 20-25 kt, though there could be some to 30 kt. Advisories
in NNW flow likely continue into early Monday morning except on
the interior rivers.

Another transient area of high pressure will bring a brief
period of lighter winds on Monday, shifting to the south in the
afternoon. Advisories in southerly channeling may be needed by
the second half of Monday night. Advisories may continue Tuesday
and Tuesday night as a system passes to the north, with winds
eventually becoming northwesterly Tuesday night. Lighter winds
are expected Wednesday as high pressure builds into the area.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory until 4 AM EST early this morning for
     MDZ008.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 4 AM EST early this morning for
     ANZ530>534-537>541-543.

&&

$$

SYNOPSIS...ADS
NEAR TERM...ADS
SHORT TERM...ADS
LONG TERM...KLW
AVIATION...ADS/KLW
MARINE...ADS/KLW