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Area forecast discussion
National Weather Service Baltimore Maryland/Washington District of Columbia
400 am EST Thu Nov 14 2019

high pressure will move offshore today as a cold front
approaches from the Great Lakes and upper Midwest. The cold
front will cross the region tonight as low pressure develops
over northern Florida. A secondary cold front will surge
southward from the eastern Great Lakes and northeastern U.S.
Friday night into Saturday as high pressure builds to the north
and low pressure meanders off the Carolinas. This low will
slowly lift northeastward offshore through early next week as
high pressure gradually retreats into the Canadian Maritimes.


Near term /until 6 PM this evening/...
high pressure has shifted offshore, and southerly return flow
will take over at the surface today. This should push
temperatures well into the 40s for most locations, possibly
pushing 50 in a few spots, especially where high clouds thin out
more. A cold front near Chicago as of early this morning will
trek eastward through the day, reaching the Allegheny crest this
evening, but with very little moisture to work with. Therefore,
only periods of mid/high clouds are expected today.


Short term /6 PM this evening through Saturday night/...
weak isentropic lift ahead of a cold front tonight, coupled
with an increase in mid-level positive vorticity advection and upper jet streak will pull
some moisture northward, resulting in spotty light rain mainly
over southern Maryland. Sprinkles are possible further north and
west given the mid/upper dynamics but low-level moisture is
lacking so measurable precip is not expected. Lows tonight will
be warmer near and east of I-95 with increased clouds, but where
clouds are higher and thinner to the west, lows will likely
drop into the 20s again. Low pressure will continue to spin off
the Carolina coast as high pressure building to the north sends
a secondary cold front south Friday into Saturday. Gusty north
winds are expected late Friday night into Saturday, but dry
conditions are expected as well with a lack of moisture and
forcing. Saturday may end up being colder than Wednesday
afternoon with the strong high building to the north.

Clouds increase from the south Saturday night as low pressure
off the Carolinas attempts to decide its next move.


Long term /Sunday through Wednesday/...
the long term presents significant uncertainty with a lot of
moving parts. At the start, low pressure looks likely to be
positioned off the Carolina coast, attempting to track
northeastward. The majority of guidance holds this low off the
coast, resulting in our region remaining dry, but a few models
continue to track it further inland, which could spell wind and
rain. Even if it stays further east, breezy conditions are
likely Sunday, potentially extending into Monday.

Uncertainty continues Tuesday into Wednesday as a deepening
shortwave dives southeastward across the region. While guidance
is in no way consistent regarding the details, the risk remains
of another coastal low pressure developing which could also
bring wind and rain to the region. However, latest models have
trended slower and weaker with any development, making it more
likely that it stays mostly dry. Temperatures through the long
term may moderate if this occurs, but any coastal storm
influence may drag temps down for a longer period of time thanks
to clouds and rain.


Aviation /09z Thursday through Monday/...
mainly VFR thru Sat. Dry cold front tonight crosses west to
east, then secondary dry cold front surges south late Fri night.
Light S flow today becomes northwest to north Fri, then gusty late Fri
night into Sat.

Conditions most likely remain VFR Sunday and Monday as a low
pressure system passes to the southeast and east, though a gusty
northeast to north wind is likely. There is a small risk that
some rain may overspread the region if this low tracks further
west, which could result in sub-VFR conditions.


light S winds with weak/dry cold front crossing through tonight.
Winds become northwest then north Friday into Saturday and strong, possibly
approaching gale.

Low pressure off the coast will result in a likelyhood of small
craft advisories on Sunday. Low-end gales can't be completely
ruled out. Winds may diminish by Monday as the system tries to
push east away from the region.


with the Arctic airmass starting to moderate, most records that
are going to fall have likely already fallen. However, there
remains a small risk that a record low could be set early this
morning. They are listed below:

Site low 11/14
dca 19/1920
BWI 18/1986
iad 13/1986


Lwx watches/warnings/advisories...
District of Columbia...none.


near term...dhof
short term...dhof

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