-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KLWX 141425
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1025 AM EDT Wed Apr 14 2021

.SYNOPSIS...
Low pressure and its associated cold front will move across the
area Thursday afternoon. Weak high pressure will gradually build
over the region Friday and into early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
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Mid morning update: Showers have broken out across much of the
area this morning. The main change made to the forecast was to
speed up the arrival of showers. These showers are pushing to
the east of the Blue Ridge (as of 10 AM), and should continue to
spread eastward toward the bay over the next hour or two.
Otherwise the previous forecast remains on track. Previous
discussion follows..

Showers are expected to break out later this morning as heights
aloft fall and upper diffluence increases ahead of an upper low
dropping from the Great Lks into the northern Mid- Atlc region.
At the surface, a low pressure center is expected to form over
srn VA tonight and move east of the area Thursday afternoon.
Showers will begin to taper off from west to east overnight this
evening as drier works its way into the area behind exiting low
pressure center. Areas of stratus and/or fog will likely
develop overnight due to light onshore flow and wet soils.
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&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
Upper low over southwestern Ontario Thursday will move ESE
along the PA/NY border to srn New England by Fri afternoon.
Upslope rain showers are likely Thu, while east of the mtns,
strengthening NW downslope flow should discourage development of
showers. Showers over the mtns will turn into snow showers Thu
night with a coating to half inch of snow possible.

Upper low/trough axis crosses the area late Thu night with mid-
level subsidence/drying expected Fri into the weekend. However,
it will be cloudy, cool, and breezy with gusts 30-35 mph
possible.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
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The blocked upper level flow pattern seen in the previous days will
begin to break down on Saturday, with quasi-zonal flow returning.
That being said, our region will reside under a fairly strong jet
streak into Saturday evening, with an impulse of upper-level
energy also sliding by near/north of the area. Could expect to
see some showers on Saturday evening into Sunday as a result.
Then another piece of upper-level energy swings through Sunday,
with yet another chance for rain showers.

The beginning of next week brings a lot more uncertainty into
the forecast. The upper-level pattern remains very active, with
both the polar and subtropical jets streams coming into play.
Can`t rule out rain either day on Mon/Tue, so keeping chance
POPs in there until a timeframe can be better nailed down.

Temps during this period gradually warm from the mid 60s to upper
60s with overnight lows in the upper 30s (mountains) to mid 40s
(elsewhere).

High pressure should return to the region towards the middle of next
week.
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&&

.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
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Developing IFR cigs with showers this afternoon with LIFR
conditions cigs/vsbys possible overnight as showers exit.
Breezy/windy Thu night and Fri with bkn cigs 035.

VFR conditions expected Saturday amid a break in the shower action.
Off and on showers possible Saturday evening through Sunday
though, with some restrictions possible at times, but should
remain mostly VFR.
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&&

.MARINE...
SCA conditions appear likely this evening over the lower and
middle Chesapeake Bay and lower Potomac River, and then, all
waters late Thursday through Friday night.

No marine hazards expected for the weekend as light winds are
expected over the waters. Off and on showers Saturday night through
Sunday though, but don`t expect much in the way of wind from those
either.

&&

.TIDES/COASTAL FLOODING...
Minor coastal flooding is expected at Annapolis and DC
Waterfront through Wed night before winds become NW Thursday.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
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DC...Coastal Flood Advisory until noon EDT today for DCZ001.
MD...Coastal Flood Advisory until 2 PM EDT this afternoon for
     MDZ508.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 6 PM this evening to 2 AM EDT
     Thursday for ANZ531>534-537-539>541-543.
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&&

$$
SYNOPSIS...LFR
NEAR TERM...LFR/KJP
SHORT TERM...LFR
LONG TERM...CJL
AVIATION...LFR/CJL
MARINE...LFR/CJL
TIDES/COASTAL FLOODING...LFR