Olney, Maryland 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

291
FXUS61 KLWX 221950
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
250 PM EST Mon Dec 22 2025

.SYNOPSIS...
High pressure shifts offshore overnight as a weak low pressure
system tracks to the north across the Great Lakes region into
Canada through Tuesday morning. The associated fronts move
through on Wednesday morning with high pressure returning in
the afternoon. A warm front slowly approaches from the southwest
on Thursday yielding some rain chances before the boundary
settles nearby or just to the south. Depending on its position,
some potential for a wintry mix would exist on Friday. A
stronger cold front arrives toward the end of the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
Surface high pressure shifts offshore this afternoon and into
the overnight. Mid level moisture is moving into the area with
mid level clouds being observed across much of the area west of
I-95. Cloud cover will continue to increase this afternoon with
high temperatures in the upper 30s to mid 40s across the
forecast area.

Overnight, a weak low pressure system tracks across the Great
Lakes region and into Canada, with the associated warm front
approaching the forecast area. As moisture advects between the
area of low pressure and the departing high, precipitation
chances increase for the northern portions of the forecast area
overnight. A slight chance to a chance of precipitation is
expected across the area with the uncertainty coming in regards
to precipitation type. Overnight low temperatures for most of
the area will be above freezing, although wetbulbing may result
in subfreezing temperatures. A wintry mix is possible to start
before precipitation type transitions to rain early Tuesday
morning. Those in the Alleghenies have the highest chances of
seeing freezing rain with sporadic coverage possible in western
Highland County. A rain/snow mix is possible across most of the
area along and north of I-66, although warm afternoon temps and
dry air at the surface will inhibit accumulations. The greatest
chances for accumulating snow is in NE Maryland, where a
dusting is possible.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
Rain moves out of the area by Tuesday afternoon with lingering
rain showers in the Alleghenies through the evening.
Temperatures will be 5 to 15 degrees warmer with highs in the
mid 40s to low 60s across the area. The main weather story will
be gusty winds as the cold front pushes across the area. Higher
elevations along the Allegheny Front may approach wind advisory
criteria, but lower elevation winds will not be as strong.
Behind the front, overnight lows will be in the 30s across the
area.

High pressure builds over the area on Wednesday with dry
conditions expected. Similar to Tuesday, there will be a large
spread in high temperatures with the Alleghenies and NE
Maryland staying in the 40s and central VA nearing 60 degrees.
Overnight and into Thursday, a warm front approaches from the
west with precipitation chances increasing from west to east
overnight. Overnight low temperatures will be in the 30s.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
The long term period will start off on Thursday with deep troughing
along the West Coast, broad longwave ridging centered over the
middle of the CONUS, and then troughing again just to the east of the
Atlantic coastline. This will place us in northwesterly flow aloft.
A weak disturbance will descend down in northwesterly flow from the
Great Lakes during the day Thursday. There`s still some disagreement
in guidance with respect to the track of this system, with some
guidance tracking the system overhead, while others keep it
suppressed off to our south and west. Depending on which solution
verifies, we could either have some showers throughout the day, or
mostly cloudy and dry conditions. Temperatures are forecast to range
from the mid 40s across northeast Maryland to near 60 in Central
Virginia.

Meanwhile, another disturbance will emerge out of the West Coast
trough and rapidly track up over the central US ridge Thursday into
Thursday night, before diving east-southeastward toward the Mid-
Atlantic on Friday. Guidance has shifted significantly southward
with the track of this system with each of the last few model runs.
As a result, many solutions now show wintry precipitation across the
northern half of the forecast area (roughly I-66/US-50 northward).
Of the solutions that do have wintry precipitation, most favor
freezing rain and sleet, but some snow can`t be completely ruled out
depending on the ultimate track of the system. The upstream flow
pattern across the North Pacific (from which this system will
originate) is highly complex at the moment, with critical pieces
that will come together still to the west of the California coast,
in the Gulf of Alaska, and in the Bering Strait. Another closed
upper low to the west of Hawaii will likely also have a major impact
on how the West Coast trough evolves. As a result, there could still
be significant shifts with respect to the track of this system over
the next few model runs, and confidence in the forecast is much
lower than normal for five days out.

The aforementioned system will progress off to our east by Saturday,
leading to drier conditions locally. A much deeper closed upper
level low is expected to approach from the northwest on Sunday,
potentially leading to the next chance for rain. A very strong
Arctic front will likely move through later Sunday into Sunday night
as the system departs. Windy and much colder conditions are expected
by Sunday night, with precipitation potentially ending as a little
upslope snow in the mountains.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
A warm front approaching the forecast area will bring
precipitation chances to the terminals overnight and into
Tuesday morning. At all terminals except KCHO, a snow/sleet mix
is possible along the leading edge of precipitation.
Precipitation type will transition over to rain Tuesday morning
with conditions drying out by late morning. Currently have
PROB30s for -RASN, although restrictions are not expected until
after the precipitation has moved out Tuesday morning where MVFR
ceilings are possible.

A cold front moves through on Tuesday with gusty winds expected
in its wake. Southerly winds on Tuesday shift to northwest
overnight with gusts between 15-20 knots expected. VFR
conditions are expected on Wednesday as surface high pressure
returns. Winds remain out of the northwest, gusting 15-20 knots
in the morning before diminishing in the afternoon. Light winds
are expected at KCHO all day.

Sub-VFR conditions may be possible at times on both Thursday and
Friday as disturbances track toward the area from the Great Lakes.
Some showers may be possible on Thursday, and a wintry mix of
precipitation appears possible during the day Friday. Winds look
relatively light, and direction is a bit uncertain at the moment,
and will depend on the ultimate track that the systems take.

&&

.MARINE...
A Small Craft Advisory is in effect for portions of the lower
tidal Potomac and the Chesapeake Bay beginning overnight and
lasting through Tuesday morning. Gusty south winds blowing 10 to
15 knots and gusting up to 20 knots are expected. Winds diminish
below SCA criteria Tuesday night with winds shifting to
northwesterly. Additional advisories may be needed on Wednesday
as winds briefly gust 15 to 20 knots in the morning, although
the threat appears marginal and brief.

Sub-SCA level winds appear likely on both Thursday and Friday.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 1 AM to noon EST Tuesday for ANZ531-
     532-539-540.
     Small Craft Advisory from 1 AM to 3 PM EST Tuesday for ANZ533-
     534-537-541-543.

&&

$$

SYNOPSIS...AVS/BRO
NEAR TERM...AVS
SHORT TERM...AVS
LONG TERM...KJP
AVIATION...AVS/KJP
MARINE...AVS/KJP