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Area forecast discussion
National Weather Service Baltimore Maryland/Washington District of Columbia
953 PM EDT Sat may 27 2017

Synopsis...
weak low pressure will shift east the area this evening. A
trailing frontal boundary linger south of the area into Sunday
morning. A weakening cold front will move east through the area
Monday morning. Upper level low pressure will linger north of
the Great Lakes Monday night through the remainder of the week
with persistent weak high pressure over the mid-Atlantic.

&&

Near term /overnight/...

Low pressure moves off with light onshore flow filling in
behind from high pressure centered over New England. This should
allow low clouds to develop across the area with patchy fog
west of I-95. Humid, but cool tonight with min temps near 60f.

&&

Short term /Sunday through Monday night/...

Deep upper level low pressure approaches Lake Superior Sunday
with a broad warm sector ahead. The cold/occluded front will
push east across the Midwest Sunday. Low pressure looks to
develop over in Sunday afternoon and lift NE over the eastern
Great Lakes Sunday night. This should keep most of the heavy
rain potential north of the area. However, will stay the course
with a heavy rain mention in the severe weather potential statement for Sunday late
afternoon/night as ingredients of pwats of 1.5in and
convergence from the wave approaching from the west.

The front crosses the area Monday/Memorial Day morning with
precip generally ending by midday. Increasing sunshine and 15c
850mb temps mixing down in westerly flow should allow Max temps
in the low to mid 80s.

&&

Long term /Tuesday through Saturday/...
dry conditions expected Tuesday before a weak cold
front moves through Tuesday night into early Wednesday. Some
scattered showers and a few thunderstorm possible over our area but
mainly dry conditions overall.

Another cold front moves through Wednesday night into Thursday. This
boundary could bring a chance of showers and thunderstorms Wednesday
into Thursday, but ensemble spread leaning towards a drier solution.
There is higher uncertainty into Friday and Saturday as models
disagree, but again, the ensemble spread looks mostly dry. So
overall during this period, we are looking into mostly dry
conditions with periods of showers and maybe a thunderstorm.

High temperatures will be in the 70s and 80s... some 60s at higher
elevations. Low temperatures in the 50s and 60s, with some 40s.

&&

Aviation /02z Sunday through Thursday/...

Onshore flow in the wake of the low will allow low/IFR cigs by
late tonight western District of Columbia metros.

A cold front crosses the area Monday morning with thunderstorms
mainly west of the District of Columbia metros Sunday night.

Mostly dry/VFR conditions expected Tuesday into
Thursday with sub-VFR conditions at times with boundaries moving
through. Gusty winds expected on Wednesday afternoon/evening, up to
20 kt.

&&

Marine...
sub-Small Craft Advisory southerly flow backs to onshore as low pressure shifts
east over the area tonight. Flow shifts back to southerly but
remains sub-Small Craft Advisory Sunday ahead of a weak cold front that crosses
Monday morning.

Mostly dry conditions expected Tuesday into Thursday
with some showers and maybe a thunderstorm at times with boundaries
moving through. Gusty winds expected on Wednesday afternoon/evening,
up to 20 kt... a Small Craft Advisory may be needed.

&&

Tides/coastal flooding...
water levels hanging around a half-foot to one foot above
astronomical normals.

Onshore flow will begin to mark an increase late tonight into
tomorrow. Advisory in effect for St. Mary's County. St George
Island will be the most susceptible site (for minor flooding)
early Sunday morning, although Solomons may come close.
Widespread action stage at high tide elsewhere.

For the Sunday morning high tide (the higher of the two)
believe Annapolis and District of Columbia southeast Waterfront have the potential to go
over minor threshhold. By early Monday morning, most sites
should reach the minor threshold.



&&

Lwx watches/warnings/advisories...
District of Columbia...none.
Maryland...coastal flood advisory from 1 am to 9 am EDT Sunday for mdz017.
Virginia...none.
WV...none.
Marine...none.

&&

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