646
FXUS61 KLWX 190829
AFDLWX
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
329 AM EST Thu Feb 19 2026
.WHAT HAS CHANGED...
Monitoring fog and low clouds this morning for any potential
Dense Fog Advisories. On track for a steady rain this afternoon
into tonight. Looking ahead to Sunday, the 00Z guidance has
trended higher regarding snow chances across the area.
&&
.KEY MESSAGES...
- 1) Cloudy and rainy conditions through Friday as a stalled
front meanders nearby.
- 2) Low pressure tracking nearby brings a slight winter storm
threat to the forecast area this weekend, followed by colder
than normal temperatures early next week.
&&
.DISCUSSION...
KEY MESSAGE 1...Cloudy and rainy conditions through Friday as a
stalled front meanders nearby.
A stalled frontal boundary analyzed right along the Potomac River
this morning is going to be pushed south through the day as high
pressure builds into southern New England. The latest 3 AM obs show
easterly flow north of the frontal boundary advecting low clouds and
fog into north/northeast MD. Expect this to become more widespread
through the rest of this morning, with locally dense fog possible.
The most likely areas that could need a Dense Fog Advisory are in
north/northeast MD.
A shortwave trough will traverse the northern Mid-Atlantic this
afternoon. Warm advection overrunning the frontal boundary is going
to produce light to moderate rain that spreads from southwest to
northeast during the late morning afternoon. A period of steady
moderate rain, possibly heavy at times, is expected from late
afternoon to this evening. Rain amounts are forecast between half to
three quarters of an inch. A thunderstorm or two is possible in the
Alleghenies this evening as convection from the OH Valley moves
east. The temperature forecast today is a bit trick since it`ll
depend on the exact location of the frontal boundary. Those to the
north will see temps reach the low 40s, and those to the south reach
the low to mid 50s.
A light rain/drizzle continues for much of the night. The high res
guidance does indicate a dry slot possible, so precip could cease
for a period of time late this evening. Fog is possible once again
tonight, though dense fog looks less likely as a second shortwave
brings another round of steady rain overnight.
Surface low pressure is forecast to track across the central Great
Lakes Friday. This drags a stronger cold front across the area
Friday afternoon. Rain is forecast to continue through Friday
morning, then come to an end from west to east in the afternoon. An
even tighter temp gradient is likely Friday as highs reach the low
to mid 60s in the Shenandoah Valley / central VA, with 50s to the
north/east and possibly only upper 40s in northeast MD.
Not much cold air arrives behind the front for Saturday as highs
will reach the low to mid 50s.
KEY MESSAGE 2...Low pressure tracking nearby brings a slight winter
storm threat to the forecast area this weekend, followed by colder
than normal temperatures early next week.
A high energy but low predictability pattern looms for late this
weekend. The pattern is forecast to be very amplified but in flux as
a deep upper-level low digs out of the Gulf of Alaska inducing a
downstream ridge-building event over the western U.S. This pattern
amplification in the vicinity of western North America comes with
low predictability due to data sparse regions over the North
Pacific. Meanwhile, a pair of downstream upper lows interact/merge
over Maritime Canada, with inherent low predictability with two
cutoff lows interacting.
If the upstream ridge-building event takes place a bit further west
near 120 W longitude on Saturday, downstream trough amplification
would be favorable for phasing over the mid MS Valley into the OH/TN
Valleys Saturday night. A subsequent low track hugging the coast
would become more likely in this scenario, aided by downstream
blocking and a potential source of cold air given the upper lows
over Maritime Canada and surface high pressure attempting to ridge
into northern New England.
There is an appearance of an inverted trough signature in a subset
of model guidance over the last couple cycles, given interaction
between a more amplified northern stream wave and a bit more distant
offshore southern stream low. This could factor into precipitation
amounts and placement.
The 00Z ensemble suites (European, GFS, Canadian, Euro AIFS) all now
have at least some snow across the area Sunday into Sunday night.
This continues the trend toward higher QPF/snow amounts in the last
3-4 model cycles. Still, the spread remains quite large with many
ensemble members indicating little to no snow, while others do show
significantly higher amounts.
There are several variables at play here that likely won`t be
resolved with much more clarity for another day or two. This will
determine the difference between a couple of strung out waves
passing through with little fanfare, a modestly impactful period of
snow showers, and a more significant wintry precip event.
Of note, the higher sun angle later in the season becomes a factor
especially for lower elevations if precip occurs during the day.
Cold air will also filtering into the region as the storm in
question approaches, rather than being locked-in beforehand, which
offers another layer of uncertainty in p-type.
Regardless of exactly how the details of the Sunday-Monday system
play out, another shot of below normal temperatures is favored for
early next week. Currently, high temperatures in the 40s (30s in the
mountains) with lows in the 20s (teens in the mountains) are
forecast through Tuesday night, with some midweek moderation
after.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
Sub-VFR conditions are expected to develop at all the terminals this
afternoon. Low clouds and fog are possible this morning at most
terminals, and most likely at BWI/MTN as low stratus advects in from
southern PA/NJ. IFR to LIFR conditions are expected this afternoon
into tonight as a steady rain overspreads the area. Drizzle and
fog/mist persist into tonight. Conditions begin to improve Friday
late morning to afternoon as a cold front moves through the area.
VFR conditions return Friday evening into Saturday.
There is uncertainty in the track, strength, and timing of a coastal
low Sunday into Monday. Restrictions are likely especially if this
low tracks closer to the coast, and if enough cold air is in play
then rain may change to snow late Sunday into Monday. NE to NW winds
of 10-20 kts with gusts of 20-30 kts are possible, depending on the
exact track and strength of the low as it passes by.
&&
.MARINE...
Favorable marine conditions are likely to persist through Saturday.
While a brief period of near-SCA winds is possible Friday afternoon
into Friday night, this is likely to be sporadic enough to not
warrant a Small Craft Advisory. Rain is expected at times today
through Friday afternoon, with dense marine fog possible through
Friday morning.
A large and potentially strong area of low pressure may pass south
and east of the waters Sunday into Monday. This introduces to
potential for at least SCA conditions in NE to NW flow, with rain
and/or a rain/snow mix possible.
&&
.TIDES/COASTAL FLOODING...
Sensitive locations are likely to reach Action Stage during
high tide each day. Minor tidal flooding possible Friday into
Saturday at the more sensitive tidal locations as a worst case
scenario.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...None.
&&
$$
DISCUSSION...KRR/DHOF
AVIATION...KRR/DHOF
MARINE...KRR/DHOF
NWS LWX Office Area Forecast Discussion