736
FXUS61 KLWX 091933
AFDLWX
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
233 PM EST Sun Feb 9 2025
.SYNOPSIS...
High pressure remains in place across the region through Monday. A
low pressure system brings significant wintry precipitation Tuesday
into Tuesday night. A brief break in precipitation possible
Wednesday, then another area of low pressure moves through Wednesday
night into Thursday.
&&
.NEAR TERM /THROUGH TONIGHT/...
Conditions have mostly dried out across the area, aside from some
very light snow at times in western Garrett County. A mix of sun and
clouds along/north of I-66, with more ample sunshine to the south.
The Alleghenies stay cloudy through the night. Highs this afternoon
in the 40s, with some low 50s in Central VA. Cloud cover builds in
tonight, though lows still settle in the 20s to low 30s.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Benign weather conditions expected Monday as an area of surface high
pressure over the OH Valley slides east across PA/NJ, and into the
western Atlantic. On and off clouds throughout the day, though dry
conditions prevail. Highs in the 40s, with 30s in the mountains.
An active weather pattern ensues for the middle portion of the week
as several waves of low pressure bring wintry precipitation to the
area starting Tuesday.
From a synoptic look, flow aloft remains purely zonal over the
eastern CONUS. The confluence of the northern and southern branch
jet streams will create an impressive jet stream over the OH Valley
to PA/NY/southern New England. Several fast moving waves of low
pressure aloft ride along just south of the jet streak. At the
surface, several associated areas of low pressure move from the Deep
South to the lower Mid-Atlantic, then out to sea.
The main concern on Tuesday will be the temperatures, which are
currently forecast to be in the mid to upper 30s. The surface high
to our north falls apart as it moves into the Atlantic, weakening
the source region of cold air into our area. This makes the p-type
forecast tricky for daytime Tuesday. It is possible that snow
struggles to accumulate over most of the area, unless marginal temps
are overcome by high precip rates. This seems most likely along the
I-64 corridor, but model guidance is still uncertain on where the
high precip rates occur Tuesday. Nonetheless, precipitation is
forecast to begin as all snow Tuesday morning over the southwest
CWA, then spread northeast through the afternoon.
Cooling temperatures Tuesday evening into Tuesday night, combined
with steady precipitation, is forecast to produce accumulating snow
across the entire area. Warm air advection aloft along and south of
the surface frontal zone could cause p-type to transition to
freezing rain (possibly mixed with snow) over the central Shenandoah
Valley and parts of Central VA.
Through Tuesday night, the current forecast is for 3-5" of snow,
with higher totals up to 6-7 possible". Where confidence is highest,
a Winter Storm Watch will be issued shortly, along/south of I-66/US-
50. Additional considerations for Watch expansion, and issuances of
Winter Weather Advisories is expected tonight into tomorrow. Stay
tuned to the latest updates at weather.gov/lwx/winter.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
The active winter pattern will continue into Wednesday with the main
winter precipitation shifting from a predominately snow regime to a
wintry mix setup. A surface low pressure associated with the first
round of wintry/snow precipitation is likely to shift off-shore
sometime on Wednesday morning. A brief break in precipitation is
likely on Wednesday, but precipitation is forecast to build back
into the region by late Wednesday afternoon and into the evening.
As the low shifts off-shore, the weather pattern will become more
favorable for cold are damming along and west of the Blue Ridge as
high pressure builds over eastern Canada with low pressure off the
eastern seaboard. A blocking high setup will lead to locked in near
to below freezing temperatures at the surface as a warm overruning
air mass associated with warm front to south leads to an increased
threat for freezing rain especially for areas along and west of the
Blue Ridge Mountains. Areas east of the mountains will likely see
more rain or rain/snow mix Wednesday evening into early Thursday
morning.
The system that affects our region Wednesday into Thursday morning
is forecast to lift out of our region sometime on Thursday. A period
of mostly dry and near normal temperatures are favored to return
Thursday into Friday as weak ridging builds over the eastern
seaboard. A clipper system to the south may bring the only chance of
precipitation during this period to the southern parts of our
region.
Another system may impact our region this weekend as a warm front
potentially starts to lift northward through our area on Saturday
bringing the next chance for widespread precipitation. Depending on
the positioning of the surface low, the region could experience a
moderate rain event this weekend or more of a wintry mix. If the
precipitation falls as predominately rain, a threat for flooding
will be possible due to enhanced runoff combined with moderate heavy
rain and some possible snow melt.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
VFR conditions are expected through Monday evening. Gusty northwest
winds around 25 knots continue through this afternoon, then quickly
diminish this evening into tonight. Light north/northwest winds
Monday become south/southeast on Tuesday.
Sub-VFR conditions are likely by Tuesday afternoon at all terminals
as an area of low pressure moves across the region. Low clouds and
low visibility are likely as wintry precipitation, mostly snow,
overspread the region from southwest to northeast.
SubVFR conditions are likely Wednesday into Thursday morning as
wintry precipitation affects all terminals. VFR conditions are
likely to return Thursday afternoon into Friday. A period of gusty
conditions out of the west to northwest are possible on
Thursday.
&&
.MARINE...
Hazardous marine conditions today as northwest wind gust around 25-
30 knots across all the waters. Small Craft Advisories are in
effect. These winds diminish this evening, then quickly lower
overnight as high pressure builds overhead.
North winds Monday veer east to southeast Tuesday, while remaining
at 5-10 knots. An area of low pressure moves across the area on
Tuesday, bringing wintry precipitation to all the waters.
Small Craft Advisories maybe needed Thursday into Friday
morning.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 6 PM EST this evening for
ANZ530>543.
&&
$$
SYNOPSIS...KRR
NEAR TERM...KRR
SHORT TERM...KRR
LONG TERM...JMG
AVIATION...KRR/JMG
MARINE...KRR/JMG
NWS LWX Office Area Forecast Discussion