Olney, Maryland 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

451
FXUS61 KLWX 260801
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
401 AM EDT Thu Mar 26 2026

.WHAT HAS CHANGED...
No changes. Small craft advisories remain in effect for all
waters through early this morning then again early this
afternoon through late this evening.

&&

.KEY MESSAGES...
- 1) Strong cold front brings showers and some thunderstorms
  this evening into Friday.

- 2) Below average temperatures return this weekend before
  another warm up ensues next week.

- 3) Warming temperatures across the area as surface high
  pressure shifts offshore and a front stalls to the northwest.

&&

.DISCUSSION...
KEY MESSAGE 1...Strong cold front brings showers and some
thunderstorms this evening into Friday.

A strong cold front approaches from the OH Valley. Return flow
on the backside of the high will strengthen southerly flow.
This is going to cause temps to reach well above normal, in the
mid to upper 70s across the area (with upper 60s to 70F in the
mountains).

An upper trough from the Great Lakes will slide south toward the
area later today, with an associated cold front also pushing
south from the OH Valley/PA this evening into tonight. The cold
front is likely to lose much of its upper support as the trough
aloft flattens. A few strong thunderstorms are possible in
western and central MD and parts of the eastern West Virginia
Panhandle later this evening, with gusty winds as the main
threat. This is where SPC maintains a Marginal Risk (level 1 of
5) for severe thunderstorms have been drawn. However, the loss
of strong synoptic support and lower instability due to evening
arrival time likely limit the intensity and coverage of any
stronger storms.

Models are in good agreement on 0.5-0.75" of rain in the Alleghenies
and parts of the Potomac Highlands as the front moves through.
Elsewhere, a wetting rain of 0.25-0.50" are likely tonight through
Friday afternoon. The front will be slow to cross on Friday,
with cooler air moving in while light rain continues into the
afternoon.

The warmest temps on Friday will occur early in the morning, then
we`ll see a gradual cooling through the day. The front clears Friday
evening, ushering in a cooler airmass Friday night as lows drop to
the 20s to mid 30s.

KEY MESSAGE 2...Below average temperatures return this weekend
before another warm up ensues next week.

A progressive synoptic pattern continues across the country with
below average mid/upper heights pushing through the eastern U.S.
this weekend. A brunt of this cold air arrives on Saturday with 850-
mb temperatures ranging around -6 to -8C. Mixed dry adiabatically
will carry high temperatures into the mid 40s to low 50s, locally in
the 30s to low 40s across the mountains. Residual height gradients
should favor a breezy northwesterly wind which comes with mostly
sunny skies. As a 1036-mb anticyclone settles over the Mid-Atlantic,
strong radiational cooling effects lowers forecast lows into the mid
20s to near freezing. Temperatures rebound for the second half of
the weekend as heights build behind the passing trough. Sunday`s
highs return well into the 50s amidst prevailing southerly flow.

As the longwave trough pushes out in the Atlantic, a broad upper
ridge pulses northward from the Gulf of America. Subsidence in this
regime coupled by a stationary boundary arcing west-east across
southern New England will yield a warm up for next week. The profile
features low-level south to southwesterly flow, with westerlies
aloft. By the middle of next week, widespread 70s to near 80 degrees
look possible. However, this does come with a lot of ensemble spread
which is likely due to the position of the boundary to the north.
This backdoor front could easily be further south than currently
forecasted.

KEY MESSAGE 3...Warming temperatures across the area as surface
high pressure shifts offshore and a front stalls to the
northwest.

Surface high pressure shifts offshore Sunday and Monday with
return flow ushering in warming temperatures and increasing
cloud cover. High temperatures will be in the 50s for most on
Sunday with dry conditions expected as high pressure remains
overhead. As high pressure shifts offshore, southerly winds will
lead to warming temperatures and highs in the mid 50s to 60s.
Additionally, precipitation chances increase in the northwest
portions of the forecast area as a front crosses the Great Lake
regions and stalls.

Temperatures continue to warm through mid week with highs on
Wednesday in the 70s for most. Chance to slight chance of
precipitation lingers through midweek as the front remains nearby.

&&

.AVIATION /07Z THURSDAY THROUGH MONDAY/...
VFR conditions are expected through today as high pressure
moves offshore. South to southwest winds gust around 20 to 25
knots this afternoon.

A cold front moves into the area this evening into Friday,
possibly bringing sub-VFR conditions to area terminals. A period
of persistent showers is likely Friday morning to afternoon,
then conditions improve from north to south Friday evening as
the front moves through.

VFR conditions are expected this weekend with a dry pattern. A
residual brisk northwesterly wind is likely on Saturday with
afternoon gusts to around 15 to 20 knots.

VFR conditions are expected Sunday and Monday as cloud cover
increases due to a nearby front. South winds on Sunday gust  15
knots throughout the day. Winds shift to southwest on Monday,
gusting 15 to 25 knots.

&&

.MARINE...
SCA remain in effect for all the waters through early this
morning and then again this afternoon and evening.

SCA may be possible on Friday behind the front and due to the
building area of high pressure.

A brisk northwesterly wind continues into Saturday with Small Craft
Advisories likely needed through the afternoon hours. Winds shift to
southerly on Sunday, but stay below advisory levels. Another ramp up
is possible early next week with a shift to southwesterlies
ensue.

South winds Sunday shift to southwest Monday. Winds increase to SCA
criteria Sunday night with advisories likely throughout the day on
Monday. Winds diminish Monday night.

&&

.FIRE WEATHER...
Fire weather may become an issue over portions of the area Saturday
through Monday pending on how much rainfall we see with the front on
Friday. A wetting rain of 0.25-0.50" of rainfall looks likely, some
parts of the Alleghenies and Potomac Highlands possibly getting
close to 1" of rain.

Minimum RH values will fall into the 25 to 35 percent range each
afternoon this weekend, with wind gusts of 15 to 25 mph. Right now,
the greatest threat appears to be over the severe drought area of
central VA and the Shenandoah Valley.

&&

.TIDES/COASTAL FLOODING...
Elevated tide levels are possible at sensitive locations during the
early afternoon high tide cycle today. Coastal Flood Advisories
are possible. A strong cold front moves across the area Friday,
with offshore winds lowering water levels through the weekend.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory until 6 AM EDT early this morning for
     MDZ008.
     Small Craft Advisory from 1 PM this afternoon to midnight EDT
     tonight for MDZ008.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 6 AM EDT early this morning for
     ANZ530>543.
     Small Craft Advisory from 1 PM this afternoon to midnight EDT
     tonight for ANZ530>543.

&&

$$

DISCUSSION...AVS/LFR/BRO/KLW
AVIATION...AVS/LFR/BRO/KLW
MARINE...AVS/LFR/BRO/KLW