Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 181855

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
255 PM EDT Mon Jul 18 2016

A surface trough will remain over the region today and a cold
front will approach from the north tonight. The cold front will
slowly pass through the area Tuesday through Tuesday night. High
pressure will build overhead for Wednesday and Thursday. High
pressure over the Atlantic will control the weather pattern for
late in the week before a cold front approaches the area early
next week.


A line of showers and thunderstorms will move across the Mid-
Atlantic region this afternoon. A severe thunderstorm watch is in
effect for most of the region. Heat and moisture have led to high
instability and thunderstorms have been able to tap into this as
they move eastward. The best shear is further north across New
England but isolated strong to severe thunderstorms are expected
through 8pm tonight. Instability ahead of the line of activity
will also lead to scattered pop-up showers and thunderstorms.

A cold front will move southward across the Ohio Valley tonight
and mild temperatures and moisture will stay around the region
through tonight. Showers and a brief thunderstorm are possible
over night with the best chance across the Central Foothills east
to Southern Maryland. Clearing of sky cover is also possible
overnight and result in fog forming into Tuesday morning. The cold
front is expected to slowly move southward overnight however winds
will be light slowing the dry air from pushing into the region.


The cold front should be located across Central Virginia Tuesday
morning and is expected to stay nearly stationary through
Tuesday which will result in dewpts elevated especially across
the southern half of the outlook area and isolated showers and
thunderstorms may initiate into the afternoon. Thunderstorms are
expected to stay sub-severe at this time. Northerly winds should
finally elevate humidity Tuesday night with dewpts dropping into
the 50s from NW to SE.

High pressure will build into the region Wednesday and dry
conditions are expected. Temps will climb into the mid 80s by the
afternoon with low dewpts giving a quick break from the heat and


While it remains dry, heat returns Thursday and Friday on
south/southwesterly flow. Humidity still relatively mild
Thursday (L60s)...but dewpoints return into the M/U60s by Friday.

Hot and humid this weekend...with heat indices AOA 100F Saturday and
near 100F Sunday. Diurnal shower and storm chances return with the
increasing heat and humidity.


A line of showers and thunderstorms will continue to move across
the terminals this afternoon and early evening. Heavy rain and
gusty winds are the main threats resulting in mvfr/ifr conditions
are they move through the terminals. VFR conditions expected
behind line and as SHRA taper off into the evening hours. A stray
shower or thunderstorm cant be ruled out at CHO overnight. Fog is
also possible at the terminals tonight and into Tuesday morning
and may result in sub-vfr conditions.

VFR conditions expected Tuesday and into Wednesday as high
pressure builds into the region. A cold front may push back into
the region Tuesday afternoon and showers and thunderstorms are
possible mainly across CHO.

VFR expected Thursday through the weekend. Though, a few
showers/storms possible Saturday and Sunday in the hot and humid


Southerly winds expected on the waters today. SCA is in effect
through the early evening. Winds will taper off tonight. Showers
and thunderstorms expected this afternoon and evening and gusty
winds are possible. SMW may be issued in thunderstorm activity.
Activity will taper off tonight however a stray shower and
thunderstorm cant be ruled out through Tuesday afternoon.

A cold front will pass through the waters Tuesday into Tuesday
night. A few showers and thunderstorms are possible ahead of the
boundary...especially across the middle portion of the Bay into
the Potomac River. Locally gusty winds are possible in any
thunderstorms that do develop. High pressure will build overhead
Wednesday into Wednesday night. A pressure surge behind the cold
front may cause winds to gust near SCA criteria overnight Tuesday
into Wednesday morning.

Mostly sub-SCA conditions expected for the end of the week and
weekend, however brief intervals of gusts up to around 20 knots
possible each night.


MARINE...Small Craft Advisory until 9 PM EDT this evening for


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