412
FXUS61 KLWX 051947
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
247 PM EST Wed Feb 5 2025

.SYNOPSIS...
An area of low pressure approaches from the west tonight into
Thursday. Another area of low pressure may potentially impact
the area this weekend. A coastal system could affect the region
sometime during the early to middle portions of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
The forecast for tonight remains mostly in track, with Ice Storm
Warnings and Winter Weather Advisories in effect through
Thursday morning. Light freezing rain and sleet begins west of
the Blue Ridge this evening, with areas of sleet east of the
Blue Ridge late this evening. Overnight, expect a transition to
a steady freezing rain in the Alleghenies, Potomac Highlands,
Northern Shenandoah Valley, the Blue Ridge Mountains, and
north-central MD/Parr`s Ridge to portions of northern VA
(western Loudoun and far northern Fauquier counties).

Elsewhere, the biggest uncertainty is going to be the marginal
temperatures. This afternoon many areas from DC to northern VA
to central VA reached 39-41F. If temps don`t fall back to around
freezing by midnight, even if freezing rain/sleet falls, the
impacts will be minimized. Still, it should be noted that dew
points are in the teens, and wet bulbs below freezing, so any
heavier precip could bring temps below freezing and allow wintry
precip to stick to the ground more easily. To show this, the ice
forecast along/east of a line from Charlottesville to Washington
DC was lowered to around 0.01-0.02". Areas just west of this,
could see ice accumulations up to 0.05".

Confidence is much higher for ice accumulations in the colder
climo regions of northern VA and north-central MD where around a
tenth of an inch of ice is expected. Locally higher amounts will
occur in the Catoctins.

Where Ice Storm Warnings are in effect the cold air hangs on the
longest, leading to ice accumulations around two to three tenths
of an inch. Other areas along and west of I-81 will see varying
degrees of ice accumulation, with higher confidence for elevated
ridges. The central Shenandoah Valley from Harrisonburg
southward likely sees just a few hundredth of an inch of ice on
the valley floor, that quickly increases up the slopes.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
Wintry precipitation that lingers after sunrise Thursday, should
quickly transition to all rain by late morning as warm air
surges in. Conditions dry out into the late evening/overnight
period.

A warm front attempts to lift northward across the Mid-Atlantic
area, though the CAD wedge will take time to erode away.
Consequently, the forecast continues to favor colder
temperatures on Thursday with highs in the mid/upper 40s north
of I-66, with low/mid 50s off to the south. The warmest areas
could be west of I-81, where mid 50s to low 60s are forecast.
Given the notable temperature spread in the guidance, could see
these forecast numbers drop a bit, particularly with statistical
guidance being colder. Heading into Thursday night, most spots
will be in the mid/upper 30s, accompanied by upper 20s to mid
30s across mountain locales.

A cold front sweeps across the Mid-Atlantic region overnight on
Thursday with a brief period of tranquil weather on Friday.
Winds will be gusty at times, especially along the Alleghenies
where gusts up to 35 to 45 mph are possible. This dry
downsloping wind will help raise temperatures into the 50s for
areas south of I-66 and into the Shenandoah Valley. After a
mostly sunny start to the day, skies cloud up later on in
response to the next weather system approaching the area. Low
temperatures stay mainly in the mid/upper 20s.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Another active period starting by the weekend and into
early next week with multiple chances for wintry weather across the
Mid-Atlantic. The first of these disturbances will move in Saturday
into Saturday night. Warm advection in advance of this system will
result in a wintry mix of precipitation across the area Saturday
into Saturday night. Precipitation looks to be relatively light, but
even light amounts of ice or snow could lead to travel disruptions.
For now, most guidance favors much of the precipitation falling as
sleet and freezing rain, with a changeover to plain rain Saturday
night before precipitation ends. A little snow could also
potentially mix in towards the onset of the precipitation. The first
system will depart off toward the northeast by Sunday. Dry
conditions and gusty northwesterly winds are expected on Sunday,
with high temperatures reaching into the 40s and 50s for most (30s
mountains). Temperatures should drop back into the 20s Sunday night.

Additional weak upper level disturbances will move through both
Monday and Tuesday, potentially leading to periods of warm advection
drive, overrunning precipitation both days. The overall trend is
lower for impacts on Monday compared to previous days and the days
following but there still may be wintry precipitation across the
area on Monday.

A very small lull in the precipitation may occur Monday night
(assuming it does precipitate Monday), before a more substantial
push of warm advection driven precipitation occurs on Tuesday. Many
deterministic 00z models (such as the GFS, Canadian, and ICON) show
this largely falling in the form of snow. However, there was a
notable northward shift in both the EPS (probabilistically
speaking), and also with the deterministic run of the Euro, which
now shows mainly ice to the northwest of I-95, with rain further
southeast.

With several fast moving, low amplitude disturbances moving through,
forecast uncertainty (in terms of both precipitation amount and
precipitation type) remains high during the Monday/Tuesday
timeframe. At this point, there remains uncertainty with the chances
for wintry precipitation with these multiple systems across the Mid-
Atlantic. We will continue to monitor the trends for these systems
as we move forward closer to the event times.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
Ceilings and visibility will quickly decrease tonight from
south/west to east as freezing rain and sleet move into the
area. IFR to LIFR conditions are expected to develop tonight,
then persist through Thursday morning. Precipitation becomes all
rain by mid morning Thursday. However, low ceilings are expected
to linger through Thursday evening, improving Thursday night
behind a passing cold front.

Friday should yield VFR conditions, with northwest winds gusting
around 20-25 knots.

Sub-VFR conditions are expected Saturday with wintry precipitation
possible across the area. VFR conditions return Sunday with light
winds out of the east to southeast Saturday turning gusty out of the
northwest by Sunday.

&&

.MARINE...
Light and at times variable winds continue through this evening,
though a steady east to southeast wind develops after sunset. An
area of low pressure brings mixed wintry precip to the waters
tonight, with rain Thursday morning through Thursday afternoon.

An eventual shift to south winds is expected, leading to
possible Small Craft Advisory conditions Thursday afternoon. A
cold front sweeps across the waters late Thursday/early Friday,
with SCA conditions likely Friday.

Light sub-SCA winds are expected Saturday with mixed precipitation
expected throughout the day before gusty SCA winds build back in on
Sunday into Sunday night.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Winter Weather Advisory from 9 PM this evening to 10 AM EST
     Thursday for DCZ001.
MD...Winter Weather Advisory from 9 PM this evening to 10 AM EST
     Thursday for MDZ008-011-013-014-016>018-504-506-508.
     Ice Storm Warning from 7 PM this evening to noon EST Thursday
     for MDZ001-003-501-502.
     Winter Weather Advisory from 9 PM this evening to noon EST
     Thursday for MDZ004>006-503-505-507.
VA...Winter Weather Advisory from 9 PM this evening to 10 AM EST
     Thursday for VAZ036>039-050-051-053>057-502-527.
     Ice Storm Warning from 7 PM this evening to noon EST Thursday
     for VAZ028-031-507.
     Winter Weather Advisory from 9 PM this evening to noon EST
     Thursday for VAZ040-501-505-506-526.
     Winter Weather Advisory from 7 PM this evening to noon EST
     Thursday for VAZ025>027-029-030-508.
     Ice Storm Warning until 7 AM EST Thursday for VAZ503.
     Winter Weather Advisory until 7 AM EST Thursday for VAZ504.
WV...Ice Storm Warning from 7 PM this evening to noon EST Thursday
     for WVZ050>053-055-501>504.
     Ice Storm Warning until 7 AM EST Thursday for WVZ505.
     Winter Weather Advisory until 7 AM EST Thursday for WVZ506.
MARINE...Winter Weather Advisory from 9 PM this evening to 10 AM EST
     Thursday for ANZ530.

&&

$$

SYNOPSIS...KRR
NEAR TERM...KRR
SHORT TERM...KRR/BRO
LONG TERM...ADM/KJP
AVIATION...KRR/ADM
MARINE...KRR/ADM