Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 211442
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
942 AM EST Tue Feb 21 2017

.SYNOPSIS...
High pressure is centered over northern New England. Cooler air
will seep south into the Mid Atlantic today. A weak disturbance
will cross the area tonight into Wednesday. High pressure will
be located off the southeast coast of the United States late in
the week. A cold front will pass through the area this weekend.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
High pressure will move off the New England coast today and an
onshore flow will allow for cooler conditions compared to recent
days...but still above climo. Climatologically highs should be
in the upper 40s. We are still expecting highs today to be in
the upper 50s...possibly lower 60s in the central Shenandoah
Valley.

A broken deck of high clouds will continue to move over the
area as moisture sneaks in ahead of an upper-level disturbance.
Partly to mostly cloudy skies are expected.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
Another "non-Feb meteorological feature" is that the jet stream
will be running along the US/Canada border for the next several
days. This will ensure that cold air is held at bay.

Took a look at precip deficits since Dec 1: all major obs sites
(DCA,IAD,BWI,MRB,CHO) are below normal. The three major airports
are all 2-2.5" below normal. CHO is 3.25" below. Ten hour fuel
moisture is 9-10%. None of this is terrible but we are moving
into a primary fire weather season so moisture would be
beneficial. Unfortunately that "mid summer moisture" over the MS
River Valley appears like it will be breaking up as it
progresses eastward. Through Thursday precipitation chances will
be low at best.

Temperatures are expected to remain well above average. Highs
will be around 70 Wednesday and Thursday. Lows in the 40s. This
is more reminiscent of late April.

One more stat/factoid - the earliest DC cherry blossom peak
bloom was in 1990 - March 15th. In the climate section below
you`ll see that this has been the second warmest Feb in DC on
record. 1990 was the warmest; it was actually 4.1 degrees warmer
than what this Feb has been so far.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Very mild Thu night and Fri night as area remains in the warm
sector with record high minimums likely especially Fri night.
Models seem to have slow down timing of fropa on Sat a bit which
should allow for more warming and destabilization with showers
and t-storms likely along the front some of which could be
strong to possibly severe. Cdfnt clears the area by 00Z Sun with
rapidly falling temperatures Sat night. High pressure then
builds Sunday through Monday bringing cooler and more seasonable
temperatures.

&&

.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
VFR today through Wednesday. Fog development will be possible at
CHO/IAD/MRB Wednesday night.

Cdfnt will move through the area around 18Z Sat with showers and
possible t-storms some of which could be produce strong wind
gusts.

&&

.MARINE...
There are currently a few gusts on the central part of the Ches
Bay in the upper teens. We`ll keep our eyes on this but at the
moment am not expecting to issue an SCA. Beyond this morning am
not anticipating issuing an SCA through Thursday.

T-storms Sat may produce strong wind gusts and may require
SMWs.

&&

.CLIMATE...
Did a check to see how warm it has been both for meteorological
winter and since Feb 1 at the three major airports in terms of
ranking (average temp): The statistics below are from February
1st through February 20th.

        Since Dec 1      Since Feb 1
DCA     5th warmest      2nd warmest
BWI     14th warmest     13th warmest
IAD     2nd warmest      2nd warmest

Unseasonably warm temperatures are expected during the second
half of the week. Below are record daily high maximum and high
minimum temperature values for the 22nd through 24th (Wednesday
through Friday).

February 22nd
DCA    77 (1874)    60 (1874)
BWI    74 (1874)    51 (1874)
IAD    71 (1991)    52 (1981)

February 23rd
DCA    78 (1874)    51 (1922)
BWI    78 (1874)    52 (1874)
IAD    73 (1985)    51 (1975)

February 24th
DCA    78 (1985)    52 (1975)
BWI    79 (1985)    55 (1985)
IAD    79 (1985)    53 (1985)

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...None.

&&

$$
PRODUCTS...LASORSA/WOODY!/LFR



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