Area Forecast Discussion
Issued by NWS Sterling, VA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
308
FXUS61 KLWX 260900
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
400 AM EST Sun Feb 26 2017

.SYNOPSIS...
High pressure will return to the area today and Monday. A warm
front will then lift north into the area Tuesday into Wednesday
followed by another cold front Wednesday night.

&&

.NEAR TERM /THROUGH TONIGHT/...
High pressure is centered over western Tennessee this morning.
Locally, gusty northwest winds continue, though they have been
subsiding over the past several hours. Expect somewhat breezy
conditions to continue through the morning, subsiding this
afternoon as the surface high moves into the Carolinas. There
will also be some stratocumulus clouds across the northern half
of the area through that time, as flow aloft remains somewhat
cyclonic across the Great Lakes. While it may feel chilly
compared to recent days, high temperatures will be within a few
degrees of normal, ranging from the mid 40s to lower 50s.

Tonight will be tranquil as the high moves off the Outer Banks.
Some mid level clouds will advance late, but there should still
be some radiational component to temperatures. 20s will be
possible in outlying areas, with lower to mid 30s elsewhere.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
The pattern becomes a bit more ambiguous (in terms of well-
defined features) for Monday and Tuesday. The surface high will
set up offshore, with the subtropical ridge aloft surging a bit,
placing the Mid-Atlantic in fast WSW flow. We can say with some
certainty that there will be more clouds than sun, and
temperatures will rise back above normal. Any precipitation will
be more difficult to time, driven by packets of isentropic
ascent and subtle shortwave troughs. Monday is looking like the
drier day, with only a small chance of showers across the
northern quarter of the area in the afternoon. The better chance
of rain will come sometime on Tuesday as a warm front lifts
into the area, but due to timing difference, have kept POPs in
the chance category. Tuesday may also be a bit breezy if low
level jet winds can mix to the surface.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Wedge may linger early Wednesday but guidance is unanimous in
pushing warm front north and bringing warm sector into region
with 70s and a breezy S wind likely. Showers and perhaps a few
more thunderstorms possible especially as cold front approaches
late and at night. May have concerns as we did today, timing may
affect any severe threat though.

Gusty NW wind and much cooler behind the front on Thursday.
Upslope snow showers possible along Allegheny Front, otherwise
dry. A weak clipper system then swings through on Friday, with a
reinforcing shot of cold air behind it. Right now odds favor
rain versus snow with this system as the low stays a bit too far
north, but something to watch. Saturday then turns into a cold,
blustery day with highs struggling to reach the 40s in many
areas.

&&

.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
NW flow continues today, with 20-25 kt gusts possible through
midday before subsiding this afternoon. Stratocu will be broken
around FL050 at times through early afternoon as well. No issues
are expected tonight as high pressure slips south of the area,
which will continue through Monday as winds become southerly
around 10 kt.

Conditions may deteriorate to at least MVFR heading into
Tuesday and Tuesday night as a warm front lifts into the area --
both in terms of low clouds and period(s) of rain showers.

Sub-VFR cigs and vis possible Wednesday and Wednesday night as
warm front lifts north of the area followed by a cold front.
There is a slight chance of thunderstorms with the cold front.
Gusty NW winds (30 knots likely) with VFR cigs/vis on Thursday.

&&

.MARINE...
NW flow continues across the waters this morning. Some
decoupling is taking place nearshore, with current observations
ranging from 15-30 kt. Am expecting general 20-25 kt gusts after
sunrise this morning, gradually subsiding this afternoon. Will
leave SCA expiration at 4 PM, but some portions of the waters
may be able to be cancelled before that. High pressure will move
south of the area tonight, with lighter winds becoming
southerly by Monday morning.

Southerly flow will be the rule through Tuesday night. Wind
fields are still relatively light on Monday, right near the cusp
of SCA criteria. Have favored a forecast just below for now,
but the threat will need to be reexamined for Monday afternoon.
SCA conditions look more likely on Tuesday with a low level jet
over the region.

SCA looks likely on southerly winds as warm front lifts north of
the region Wednesday, then gales possible Wednesday night and
Thursday behind the cold front. A slight chance of thunderstorms
also exists late Wednesday and Wednesday night as the cold front
comes through.

&&

.CLIMATE...
Warmest Februaries (average temperature)
   DCA           BWI           IAD
1. 46.9 (1976)   44.0 (1976)   42.1 (1990)
2. 45.2 (1990)   43.9 (1949)   41.1 (1976)
3. 44.7 (1997)   43.3 (1890)   41.0 (1998)
4. 44.3 (2012)   42.7 (1932)   40.9 (2012)
5. 43.9 (1949)   42.6 (1909)   40.5 (1997)

Feb 2017 (through the 25th)
DCA: 47.6    BWI: 44.3    IAD: 45.1

Warmest Winters (Dec 1-Feb 28/29)
   DCA              BWI              IAD
1. 44.7 (1931-32)   45.3 (1931-32)   40.0 (2011-12)
2. 44.3 (1889-90)   44.4 (1889-90)   39.7 (2001-02)
3. 43.3 (2011-12)   42.4 (1948-49)   39.4 (1997-98)
4. 43.2 (2001-02)   41.9 (1949-50)   39.0 (2015-16)
5. 42.8 (1949-50)   41.3 (1879-80)   38.3 (1990-91)

Winter 2016-17 (through Feb 25)
DCA: 43.8    BWI: 40.5    IAD: 40.9

Driest Februaries (total precipitation)
   DCA           BWI           IAD
1. 0.35 (2009)   0.26 (2009)   0.25 (1978)
2. 0.42 (1978)   0.36 (2002)   0.35 (2009)
3. 0.47 (2002)   0.56 (1978)   0.46 (2002)
4. 0.62 (1901)   0.63 (1977)   0.49 (1977)
5. 0.66 (1977)   0.65 (1901)   0.68 (1968)

Feb 2017 (through the 25th)
DCA: 0.34    BWI: 1.21    IAD: 0.33

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 4 PM EST this afternoon for
     ANZ530>543.

&&

$$
SYNOPSIS...RCM
NEAR TERM...ADS
SHORT TERM...ADS
LONG TERM...RCM
AVIATION...ADS/RCM
MARINE...ADS/RCM
CLIMATE...



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.