Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 160815
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
415 AM EDT Mon Apr 16 2018

.SYNOPSIS...A strong cold front will cross the area later this
morning. Weak high pressure will gradually build back in for
Tuesday and Wednesday before another low pressure system crosses
the region Thursday. High pressure builds again over the region
for the latter part of the week.

&&

.NEAR TERM /THROUGH TONIGHT/...

Rain/showers with embedded t-storms will be moving east of the
area by 12Z this morning if not a little sooner with frontal
passage. Cloudy and breezy today with still a risk of a shower
due to wrap around moisture and weak instability as upper
low/cold pool aloft approaches from the west. Over the
Appalachians, there will be upslope precipitation with wet snow
showers, but with little accumulation during the daytime hours
due to temperatures in the mid 30s. Best chance of snow
accumulation will occur during the evening hours before upper
trof axis moves across. We`ll be issuing a freeze watch for
several counties on the I-81 corridor where freezing
temperatures are expected and the growing season has started.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...

Quite cool and breezy especially for mid April as area remains
under cyclonic flow aloft associated with low pressure over
the St. Lawrence river. Dry conditions expected except for some
upslope precipitation over the Appalachians.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...

Next frontal passage is expected Thursday with a chance of
showers. Precip will be significantly less with this system due
drier westerly sfc wind trajectories and not enough moisture
return. Quiet weather expected for the latter part of the week
as high pressure builds in.

&&

.AVIATION /08Z MONDAY THROUGH FRIDAY/...

IFR conditions in rain expected through 12Z today, then
conditions improving rapidly to MVFR/VFR. Still bkn cigs 030-040
and breezy.

Frontal passage expected Thu with sct showers.

&&

.MARINE...Gale warning through 12Z today, then SCA through the
first half of the week as pres gradient remains tight.

&&

.HYDROLOGY...Flash flood warning in effect for the Cameron run
in Alexandria and Fairfax county where river gauge indicated the
creek had risen above flood stage. A flood warning is also in
effect for the South Branch Potomac River in Franklin, WV.

&&

.TIDES/COASTAL FLOODING...Minor coastal flooding is expected at
most sites, perhaps even moderate flooding at Annapolis and
Straits Point. We`ll reevaluate situation later this morning and
upgrade to a warning if necessary.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Coastal Flood Advisory until 11 PM EDT this evening for MDZ014.
     Coastal Flood Advisory until 5 AM EDT Tuesday for MDZ016.
     Coastal Flood Advisory until 10 PM EDT this evening for MDZ011.
     Coastal Flood Advisory until 7 AM EDT Tuesday for MDZ017.
VA...Coastal Flood Advisory until 5 AM EDT Tuesday for VAZ057.
WV...None.
MARINE...Small Craft Advisory from 8 AM this morning to 6 PM EDT this
     evening for ANZ530>543.
     Gale Warning until 8 AM EDT this morning for ANZ530>543.

&&

$$
SYNOPSIS...LFR
NEAR TERM...LFR
SHORT TERM...LFR
LONG TERM...RCM
AVIATION...RCM/LFR
MARINE...RCM/LFR
HYDROLOGY...LFR
TIDES/COASTAL FLOODING...LFR



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