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000
FXUS61 KLWX 181410
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1010 AM EDT Wed Apr 18 2018

.SYNOPSIS...
Weak high pressure over the area will move offshore
later today. Low pressure will move across the Ohio valley this
afternoon and evening and into the Northeast on Thursday
dragging a cold front through the area early on Thursday. High
pressure will build in over the weekend and hold through the
first half of next week.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY/...
Clear to mostly clear skies are observed over most of our area,
with some clouds lingering along the warm front towards the
central Shenandoah Valley. Temperatures have risen between the
upper 30s and the low to mid 40s at this time, therefore the
Freeze Warning was canceled earlier this morning

Temperatures will warm up appreciably today with the warm front
off to the southwest and winds shifting southerly as high
pressure slides off the southeastern U.S. coastline. Plentiful
sunshine at least for the first half of the day will allow
temperatures to warm nicely, topping out this afternoon in the
lower to middle 60s for most, and upper 60s seem like a good bet
along our southern zones. We will see clouds increase later
this afternoon and into the evening as low pressure approaches
from the west and the warm front continues its slow track
northeastward into the area.

Showers will develop overnight, sticking mostly to the Allegheny
Highlands as low pressure passes just to our north. The ECMWF brings
the track of the low a little further south than other global
guidance, which would favor a bit more shower coverage east of the
mountains. Will keep chance POPs north and west of the metro areas
tonight, with likely POPs along the Allegheny Highlands.
Temperatures tonight will be mild with ample cloud cover and a
southwesterly flow aloft. Lows will generally bottom out in the 40s
to near 50 in the city centers.

&&

.SHORT TERM /6 AM THURSDAY THROUGH FRIDAY NIGHT/...
As low pressure moves to our north Thursday morning, a cold
front will drag across the area, turning winds gusty out of the
northwest. Despite cold air advection kicking in around midday
on Thursday, temperatures will still manage to near 60 in the
metro areas, with lower to middle 50s to the north and west,
with upper 30s to lower 40s along our far western zones. As cold
air advection continues, the rain showers over the Alleghenies
will transition to snow showers during the day. A coating to an
inch or two of snow is feasible into Thursday evening.

Canadian high pressure will build to our west northwest on Friday,
with gusty northwest winds starting to subside by Friday evening.
Mostly clear skies and dry conditions expected Friday and Friday
night, with highs in the lower to middle 50s, and lows in the
30s.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
High pressure will be in control of the region over the weekend
through the first half of next week and support dry conditions.
Temperatures will be on the slow rise as heights rise, but still
a little cooler than normal. Next chance of precipitation is not
expected until at least Wed when a southern stream cutoff low
approaches from the south, but timing remains highly uncertain.

&&

.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
VFR conditions are forecast across all terminals today as high
pressure traverses the area, keeping winds light and generally
southerly at 10 knots or less. Clouds will increase late this
afternoon and evening, with VFR CIGs, as low pressure approaches
from the west and passes just north of the terminals through
Thursday morning. Shower activity will be light and likely remain
west of the terminals, with MRB seeing the best shot of brief MVFR
conditions with this activity. Winds turn gusty out of the northwest
by midday Thursday with a frontal passage, gusting upwards of 30 to
35 knots into Thursday evening.

Gusty northwest winds will begin to subside during the day on Friday
as high pressure dominates the terminals into the weekend, keeping
winds northwesterly at 10 knots or less, and prevailing VFR
conditions.

No sig wx expected Sat or Sun.

&&

.MARINE...
Do expect occasional gusts to SCA criteria along portions of
the upper Bay late morning and into the afternoon hours today,
where a strong gradient will reside, thus have issued an SCA for
these waters for this time period. Small Craft Advisories look
likely across the lower Chesapeake Bay tonight, with Gale
conditions expected for all waters during the day on Thursday as
low pressure passes to the north and the gradient strengthens
resulting in strong northwest winds. Gale Warning has been
extended through Thursday night for the Chesapeake Bay, with the
a Small Craft Advisory elsewhere as the low departs to the
northeast and high pressure builds in from the west northwest.
Small Craft may need to be extended into Friday.

Pleasant boating conditions expected Sat into Mon with winds
less than 10 kts under high pressure.

&&

.FIRE WEATHER...
Drier air advecting into the region Thursday on gusty west winds
could result in an enhanced risk of fire spread Thursday,
especially if fuel moistures decrease appreciably by then.

&&

.TIDES/COASTAL FLOODING...
DC southwest Waterfront hit minor flood this morning due to
mixed fresh and tidal input. Minor flooding is possible through
tonight.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Coastal Flood Advisory until noon EDT today for DCZ001.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 5 PM EDT this afternoon for
     ANZ530>532-538>540.
     Gale Warning from 6 AM Thursday to 6 AM EDT Friday for
     ANZ530>534-538>541-543.
     Small Craft Advisory from 6 PM Thursday to 6 AM EDT Friday for
     ANZ535>537-542.
     Gale Warning from 6 AM to 6 PM EDT Thursday for ANZ535>537-542.
     Small Craft Advisory from 8 PM this evening to 6 AM EDT
     Thursday for ANZ534-543.

&&

$$
SYNOPSIS...LFR
NEAR TERM...IMR/BKF
SHORT TERM...BKF
LONG TERM...LFR
AVIATION...BKF/LFR
MARINE...IMR/BKF/LFR
FIRE WEATHER...IMR/DHOF
TIDES/COASTAL FLOODING...IMR/DHOF