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Area forecast discussion...updated
National Weather Service Baltimore Maryland/Washington District of Columbia
914 PM EDT Tue Sep 17 2019

Synopsis...
a cold front to our south will push into the southeastern U.S.
Through tonight as Canadian high pressure builds to our north.
This high will dominate over the northeast and mid-Atlantic
region for the balance of the work week, promoting dry
conditions and cooler than normal temperatures. The high will
settle to our south this weekend.

&&

Near term /until 7 am Wednesday morning/...
sprawling high pressure is centered across the eastern Great
Lakes this evening and will continue building eastward
overnight. As drier air makes its way into the region, skies
will continue clearing overnight, with the exception of some of
the Potomac Highlands and southern Shenandoah Valley where
northeasterly winds and proximity to the front will locally
keep cloud cover nearby. Patchy fog will be possible, although
coverage and density will be limited by northeasterly flow and
dry air advection. Lows tonight will generally range from
50-60f, with low 60s in the urban centers and along the larger
bodies of water.

&&

Short term /7 am Wednesday morning through Thursday night/...
high pressure building into New England will dominate the
weather features the next couple of days, resulting in dry
conditions and cooler than normal temperatures under a east
northeast flow. Temperatures Wednesday through Thursday will
rise into the 70s under plentiful sunshine while falling back
into the 50s at night. Patchy fog will remain possible in the
predawn hours in the sheltered valleys and rural locations.

&&

Long term /Friday through Tuesday/...
high pressure will be in control over the region at the sfc and
aloft Fri through sun maintaining very warm and dry weather. Temps
will be on the rise Sat through Mon as mid-upper level ridge remains
strong. The ridge pattern begins to break down Sun night as a
positively tilted trof moves across James Bay and displaces the
ridge axis offshore. Associated (weak) cold front is fcst to cross
the area Mon night and may provide enough lift for a few showers,
although we wouldn't be talking much in terms of precip amounts
anyway. Trough axis crosses the area Tuesday with more dry/fair
weather for the middle of next week. While temps will likely cool
off a bit after the frontal passage Tue, they are still expected to
run above normal in the mid to upper 80s. While the tropical
Atlantic is expected to remain active through the end of Sep, td#10
(next storm name imelda) is not expected to be a concern to the U.S.
Mainland through at least early next week.

&&

Aviation /01z Wednesday through Sunday/...
high pressure north of the terminals will build over the region
through weeks end with a light easterly flow prevailing. As
such, dry conditions and cooler temperatures will result in VFR
conditions persisting.

VFR conditions Fri through Sat with no sig wx.

&&

Marine...
as high pressure builds north of the region and Humberto moves
well offshore, the pressure gradient will remain strong enough
for Small Craft Advisory conditions to redevelop over portions of the waters
early Wednesday and Wednesday night, possibly lingering into
Thursday morning. After which, the gradient will relax as the
high slides southward from New England and sub Small Craft Advisory conditions
return to the waters Thursday afternoon and evening.

Winds 10kt or less over the waters Fri through sun.

&&

Tides/coastal flooding...
onshore flow through Thursday will promote rising tidal
anomalies, resulting in the threat for minor tidal flooding.
Currently, have one coastal flood advisory in place for Straits
Point overnight, and additional headlines are possible
elsewhere Wednesday and into Thursday as anomalies continue to
increase.

&&

Lwx watches/warnings/advisories...
District of Columbia...none.
Maryland...coastal flood advisory from 3 am to 7 am EDT Wednesday for
mdz017.
Virginia...none.
WV...none.
Marine...Small Craft Advisory from 11 am Wednesday to 8 am EDT Thursday
for anz533-541-542.
Small Craft Advisory from 4 am Wednesday to 8 am EDT Thursday
for anz534-537-543.

&&

$$
Synopsis...bkf
near term...mm/bkf

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