Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 131837

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
237 PM EDT Wed Sep 13 2017


The remnants of Irma will move across the Ohio Valley today and
into Pennsylvania Thursday. High pressure will return to our
region during the weekend.



Have been watching a lot of clouds on satellite today - those in
the Mid Atlantic which are post-warm front in what has almost
become a damming pattern on the east side of the mountains. But
these are slowly eroding away - the fact that the highest
temperatures this afternoon are occurring in the far western
part of the forecast varea where breaks have developed. Believe
the erosion will continue though the afternoon.

And we`re also looking at the clouds associated with the "last
gasps of Irma" which is now a low pressure area over KY/IN/OH.
This will advance to the east tonight, and will bring a chance of
showers to the Highlands this evening...progressing to I-95 late

Lows primarily in the 60s, 50s farthest west, around 70 by the



Thursday the low will become an open wave over PA bringing
chances of rain to the entire area; the farther north in the
forecast area the better the chances will be. QPF is expected to
be 1/4 inch or less. Highs 75 to 80.

Shower chances will be decreasing Thursday evening as the wave
tracks into New England. Skies should be clearing late. Lows in
the lower to mid 60s east of the mountains...mid to upper 50s

There won`t be any front sweeping the moisture away Thursday
night and Friday, so would not be surprised to see fog
development Thursday night and Cu development Friday. Still -
these should both be dry. Highs Friday again around 80.

No problems expected Friday night either - lows in the 60s.



Surface high pressure will remain centered near the New England
Coast for the weekend through the middle portion of next week. An
upper-level ridge is most likely to remain overhead during this time
as well.

Subsidence from the upper-level ridge will allow for temps to remain
above climo during this time. Areas of low clouds and fog are
possible during the overnight and morning hours each day due to low-
level moisture associated with a northeast flow. A couple popup
showers are possible as well...but coverage should remain isolated
to widely scattered due to the upper-level ridge in place.

Will continue to watch Jose out in the Atlantic. There is a
possibility that it could affect the east coast of the United States
during the middle portion of next week...and this would obviously
have an impact on our forecast. For the latest information regarding
Jose...please refer to the National Hurricane Center`s website



On visible satellite it can be seen that clouds are thinning
from the south. TAF sites should see improvement through the
remainder of the afternoon. Fog is possible late tonight at
IAD/MRB/CHO. Clouds should lower during the afternoon from DC
north along with chances for rain. This will continue into
Thursday evening. Clearing is expected after midnight which
could set up fog development Friday morning.

High pressure most likely remain over the area Saturday through
Monday. Areas of low clouds and fog are possible during the morning
hours each day Saturday through Monday...otherwise VFR conditions
are most likely.



Winds to remain below SCA values through Friday.

High pressure will remain over the waters for Saturday through
Monday. Marine hazards are unlikely during this time. Continuing to
watch Jose out in the Atlantic. This has the potential to impact the
east coast of the United States...but not until the middle portion
of next week. For more information regarding Jose...please refer to
the National Hurricane Center`s website



Water levels have been slowly rising on the easterly flow.
Straits Pt, Annapolis, and Southeast DC expected to reach minor
flood levels with the high tide cycle tonight.



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