Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 240037

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
837 PM EDT Thu Mar 23 2017

High pressure will shift offshore tonight. A warm front will
cross the region Friday. A low pressure system will then
approach the region on Sunday, and cross the area Sunday night
into Monday.


High pressure will move offshore tonight and a warm front will
approach the area from the west overnight. A southerly flow will
allow for milder conditions compared to Wednesday night.
However...radiational cooling will still cause min temps to drop
into the upper 20s to the middle 30s across most areas.

Clouds will increase overnight as the warm front approaches. A
period of rain is possible toward morning...especially across
northern Maryland...eastern West Virginia and northern Virginia.
Confidence in precipitation remains low since most of the lift
associated with the warm front will be over Pennsylvania.
However...a period of light rain cannot be ruled out. Temps
will be near freezing across northern Maryland...eastern West
Virginia and extreme northern Virginia. Pockets of freezing rain
cannot be ruled out. Confidence is too low for an advisory at
this time.


Aforementioned band of light precipitation will be moving from
west to east near the northern extent of our forecast area
Friday morning. Again while the bulk of the precipitation will
remain across Pennsylvania, some light rain and patches of
freezing rain are possible, especially across eastern West
Virginia and northern Maryland. Any pockets of freezing rain
will be over by 9 am as temperatures rise above freezing across
all locations. After warm frontal passage, the afternoon should
warm significantly with breaks of sun and highs reaching the
upper 50s to mid 60s.

Dry and mild conditions expected Friday night with lows only in
the 40s to around 50F. Frontal boundary will remain north of the
region on Saturday with mainly dry conditions and warm southerly
flow. Despite high clouds, should see temperatures rise to near
or above 70F pretty much area-wide.

Closed low pressure system will be moving towards the Great
Lakes region Saturday night with high pressure building into the
Canadian Maritimes. This will strengthen the frontal boundary
over the Northeastern United States, and may push it back
southwestward towards the region overnight as a backdoor front.
However, even so, we should still remain mild, with lows near
50F. Dry conditions expected for most of the area.


Unsettled weather expected for parts of the long
term as frontal boundaries stall nearby and southerly flow brings
Gulf moisture over our area. Sunday into Monday, a low pressure
system moves east over the southern Great Lakes and into the NE
US as a frontal boundary stalls north of us. A brief dry period
is possible Monday night before another low pressure and its
front affects our area Tuesday into Wednesday. Conditions start
drying on Wednesday and into Thursday as high pressure builds
into the area. Temperatures will be above normal, with high
temperatures in the 50s and 60s, with some 70s on Monday and
Tuesday. Low temperatures will be in the 40s and 50s, with 30s
Wednesday night.


Expecting mainly VFR through Saturday night. There may be a band
of light precipitation that crosses the northern terminals late
Friday morning, but no significant reductions to ceilings or
visibilities are expected. There is the threat of some patches
of light freezing rain, with highest risk at MRB but even across
this area confidence is low.

Winds will become southerly and a bit gusty, up to 20 knots or
so, on Friday, slackening somewhat on Saturday.

Unsettled weather Sunday into Monday as frontal
boundaries stall near our area. Brief period of dry conditions
Monday night before another front approaches on Tuesday. Sub-VFR
conditions possible most of this period.


Southerly flow will increase tonight as a warm front
approaches, with SCA threat spreading up the bay and portions of
the tidal Potomac overnight and then to the adjacent waters
during the day Friday. Winds should diminish somewhat for Friday
night and Saturday. Gusts may be near SCA criteria Friday night
but with the water likely remaining cooler than the surrounding
air mass, the lack of mixing will reduce gusts over the waters
for Friday night through Saturday night.

Unsettled weather Sunday into Monday as frontal
boundaries stall near our area. Brief period of dry conditions
Monday night before another front approaches on Tuesday. Small
Craft Advisories may be needed for portions of the waters Sunday
into Sunday night ahead of the front.


MARINE...Small Craft Advisory from midnight tonight to 6 PM EDT Friday
     for ANZ531>534-537-539>541-543.
     Small Craft Advisory from noon to 6 PM EDT Friday for ANZ535-
     Small Craft Advisory from 6 AM to 6 PM EDT Friday for ANZ530-


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