Area Forecast Discussion
Issued by NWS Sterling, VA
FXUS61 KLWX 130830
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
330 AM EST Mon Feb 13 2017
Low pressure will rapidly strengthen off the New England coast
today. High pressure will briefly return for later tonight into
Tuesday. Another cold front will pass through Wednesday. High
pressure will build overhead late in the week.
.NEAR TERM /THROUGH TONIGHT/...
Scattered snow showers are occurring early this morning across
the Allegheny Front as well as northern Maryland...extreme
northern Virgina and the eastern panhandle of West Virginia.
This is in response to strong cold advection and shortwave
energy associated with an upper-level low well off to our north.
This activity should dissipate later this morning as the
subsidence inversion lowers. Accumulating snow is expected for
locations along and west of the Allegheny Front due to an
Low pressure has begun to rapidly intensify off the New England
coast and this will continue through midday before gradually
moving out to sea. A strong pressure gradient between the low
off the New England coast and high pressure over the Midwest
will continue to cause windy conditions today. Will continue
with a High Wind Warning for the ridge tops as well as the
Baltimore and Washington Metropolitan areas. The strongest winds
are expected shortly after sunrise where the mixing will
increase and line up with the strongest winds aloft. Wind gusts
of 50 to 60 mph are expected. Latest NAM/GFS bufkit show around
50 knots at the top of the mixing layer through late this
morning. Elsewhere...gusts around 35 to 50 mph are expected and
a Wind Advisory is in effect for other locations except central
Winds should gradually diminish this afternoon as the gradient
slowly weakens in response to the low moving out to sea. Wind
headlines may be able to be dropped during the mid to late
afternoon hours. Sunshine is expected across most locations with
max temps ranging from the 20s along the ridge tops of the
Allegheny Highlands...to the middle and upper 40s near
Washington and Baltimore....to near 50 in central Virginia.
High pressure will buiSCA winds likely Thursday in cold air advection behind frontal
boundary. Winds slacken late Thursday into Friday as high pressure
builds into the area. ld overhead tonight and winds will
continue to diminish. However...it will turn out seasonably
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
High pressure will move off to the east Tuesday and a southwest
flow will allow for a milder afternoon with max temps in the 50s
for most locations.
A cold front associated with the northern stream of the jet will
approach Tuesday night. Southern stream energy should stay
mostly to our south during this time. However...there may be
enough moisture for a period of rain overnight across southern
Maryland and perhaps into portions of central Virginia. Rainfall
amounts would be light. For other locations...most areas will
remain dry but there will be a few rain or snow showers possible
in the Potomac Highlands. The best chance for snow showers will
be along and west of the Allegheny Front. Any accumulating snow
will be light and confined to locations along and west of the
The cold front will pass through Wednesday and the upper-level
trough in the northern stream of the jet will build overhead
Wednesday. Southern stream energy will move off well to our
south and east Wednesday. Any leftover rain across our southern
areas will end during the morning. Blustery and seasonably
chilly conditions are expected behind the front. A few snow
showers are possible as well due to the upper-level trough
overhead. The best chance for snow showers will be along and
west of the Allegheny Front due to an upslope flow.
Low pressure will intensify off the New England Coast Wednesday
night. More blustery and chilly conditions are expected. With
the upper-level trough overhead a few snow showers cannot be
ruled out. Again...confidence for snow showers is highest along
and west of the Allegheny Front.
.LONG TERM /THURSDAY THROUGH SUNDAY/...
Relatively benign weather through the long term.
Cold air advection continues Thursday behind the front...with
breezy conditions as NW winds gust near 20-30 mph during the
afternoon. Dry nearly everywhere...except along the Allegheny
Front...where light upslope snow showers are possible through
High pressure slides to our south Friday...with westerly winds
turning southwesterly during the afternoon. This will lead to a
warming trend into the weekend as return flow reestablishes itself.
Front approaches the area late in the weekend into early next week.
Still uncertainty on frontal location...which will ultimately
determine temperature spread and precipitation chances. For now
went with a model blend until these details become clearer.
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
Strong northwest winds are expected through this morning. Gusty
winds will gradually diminish this afternoon into early this
evening. The strongest wind gusts around 45 to 50 knots are
expected through this morning.
High pressure will build overhead tonight and winds will
continue to diminish. VFR conditions are expected for Tuesday
through Wednesday night. Gusty northwest winds will return
behind a cold front Wednesday into Wednesday night with gusts 25
to 30 knots possible.
VFR conditions expected Thursday with NW wind gusts 20-25 knots. VFR
continues Friday with lighter winds as high pressure builds into the
Strong northwest winds will continue for today as low pressure
rapidly intensifies to the north. Storm warnings and gale
warnings remain in effect for the waters today. The strongest
winds will be through this morning before gradually diminishing
Winds will continue to diminish tonight as high pressure builds
overhead. A southerly flow will develop for Tuesday through
Tuesday night as high pressure moves offshore. Winds may be
close to SCA criteria...but confidence is too low for a headline
at this time.
A cold front will pass through the waters Wednesday and gusty
northwest winds are expected behind the front through Wednesday
SCA winds likely Thursday in cold air advection behind frontal
boundary. Winds slacken late Thursday into Friday as high
pressure builds into the area.
RH may drop below 30% with sustained winds of 20-30 mph in the
central VA Piedmont and central/southern Shenandoah Valley on
Monday afternoon. However, fuel moisture is above 10% for most
of the area, precluding a fire weather threat.
Strong northwest winds will continue behind a cold front today.
Tidal blowout conditions are likely...especially later today
into this evening with anomalies around 1 to 2 feet below
DC...High Wind Warning until 6 PM EST this evening for DCZ001.
MD...High Wind Warning until 3 PM EST this afternoon for MDZ501.
Wind Advisory until 3 PM EST this afternoon for MDZ003-502.
Wind Advisory until 6 PM EST this evening for MDZ016-017.
High Wind Warning until 6 PM EST this evening for MDZ004>006-
VA...High Wind Warning until 3 PM EST this afternoon for VAZ025-026-
Wind Advisory until 3 PM EST this afternoon for VAZ027>031-
Wind Advisory until 6 PM EST this evening for VAZ052-055-501-
High Wind Warning until 6 PM EST this evening for VAZ053-054-
WV...High Wind Warning until 3 PM EST this afternoon for WVZ501>503-
Wind Advisory until 3 PM EST this afternoon for WVZ050>053-055-
MARINE...Small Craft Advisory from 6 PM this evening to 6 AM EST
Tuesday for ANZ531>534-537-539>541-543.
Storm Warning until 6 PM EST this evening for ANZ530>533-535-
Small Craft Advisory from 6 PM this evening to midnight EST
tonight for ANZ530-535-536-538-542.
Gale Warning until 6 PM EST this evening for ANZ534-536-537-