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Area forecast discussion...updated
National Weather Service Baltimore Maryland/Washington District of Columbia
1014 am EDT Sat Aug 17 2019

Synopsis...
an upper-level ridge will build overhead through Monday, with
surface high pressure in the Atlantic. Hot and humid conditions
will persist during this time. The upper-level ridge will
gradually weaken Tuesday and Wednesday before a cold front
passes through Thursday. High pressure will return for late next
week, bringing noticeably cooler and less humid conditions.

&&

Near term /through tonight/...

Heights aloft will continue to rise with temperatures
trending upward. Scattered showers are expected over
northeast Maryland and the Blue Ridge mts where differential heating
boundaries are noted with isold coverage elsewhere. Otherwise,
hot and humid with temperatures in the 90s approaching 100f in a
few places.

&&

Short term /Sunday through Monday night/...
the heat and humidity continue to rise Sunday and Monday as
southerly flow persists around the high over the western Atlantic.
Temperatures will increase a touch each day, with low to middle
90s being observed. This will result in heat indices cracking
the century mark, in the low 100s and currently forecast just
under heat advisory criteria. Will have to monitor this the next
couple of days should dewpoints/temps run a touch higher than
currently forecast.

A little strong shortwave swings across the area Sunday, so have
increased pops slightly over north-northeast Maryland, with scattered showers
and thunderstorms possible Sunday afternoon and evening. Another
shot of showers and thunderstorms will exist Monday
afternoon/evening as well, but with even weaker lift aloft, the
main trigger will be left to terrain circulations. As such
will favor along and west of the Blue Ridge for scattered
showers and thunderstorms, diminishing overnight Monday.

&&

Long term /Tuesday through Friday/...
the upper-level ridge will gradually break down Tuesday through
Wednesday as an upper-level trough digs over the Great Lakes.
Surface high pressure will remain over the Atlantic during this
time. Therefore, hot and humid conditions will persist and with
lower heights in place, this will increase the chances for
showers and thunderstorms. Some storms may be strong to perhaps
even severe due to high amounts of instability from the hot and
humid conditions. However, confidence remains low this far out.

The upper-level trough will continue to dig south and east into
the northeast Continental U.S. As well as the mid-Atlantic. The cold front
associated with this system is also likely to pass through
during this time, bringing chances for more showers and
thunderstorms.

High pressure behind the front is expected to build overhead
for Friday, bringing noticeably cooler and less humid
conditions.

&&

Aviation /14z Saturday through Wednesday/...
MVFR/IFR visible/cigs are plausible at the terminals the next few
mornings as a warm and moist airmass lingers over the region.
Afternoon/evening showers and storms could yield episodes of sub
VFR conditions, but coverage is expected to be too isold for
taf inclusion at this time. With high pressure situated over the
western Atlantic, a light southerly flow will prevail through
Monday.

High pressure will remain over the Atlantic, but an upper-level
trough will build overhead. This will increase the chances for
showers and thunderstorms each day, especially during the
afternoon and evening hours.

&&

Marine...
high pressure over the western Atlantic will deliver a light
southerly flow over the waters, thus Small Craft Advisory conditions not expected
through Monday. Gusty showers/storms are possible each
afternoon/evening, however much of the time is expected to
remain dry.

High pressure will remain over the Atlantic for Tuesday and
Wednesday, causing a south to southwest flow over the waters.
Winds may come close to Small Craft Advisory criteria at times due to southerly
channeling.

&&

Lwx watches/warnings/advisories...
District of Columbia...none.
Maryland...none.
Virginia...none.
WV...none.
Marine...none.

&&

$$
Synopsis...lfr
near term...lfr

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