Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 311341

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
941 AM EDT TUE MAY 31 2016

Several weak frontal boundaries will be in the area today through
Thursday. A stronger cold front will pass through from the west
later Friday into Friday night. High pressure may briefly build
into the area Saturday before another cold front approaches
Sunday and passes through Sunday night into Monday.


Dense Fog Advisory cancelled as most areas are now seeing better
visibility. Otherwise today, the weak boundary, barely noticeable
except for weak wind shift and slight decrease in dew points, will
continue sinking southward through the region this morning. Looking
at a mostly sunny day for most with light east/northeast flow
behind boundary. Closer to the boundary across far southern
Maryland and into central Virginia/West Virginia may see a few
showers/thunderstorms develop today with 500-1000 J/KG MLCAPE and
convergence along boundary, along with added lift from the higher
terrain of the Blue Ridge and Allegheny Highlands. Severe storms
not likely with very weak wind field. Highs generally 82-87F.


Another weak boundary will approach the area this evening and
tonight. That boundary will stall in the region Wednesday/Thursday
and will re-enforce light northeast flow as it does so. A
generally quiet night tonight with additional fog development
likely. Lows upper 50s to mid 60s.

Wednesday will continue to see light easterly flow with high
pressure nosing into New England. Will see additional chances for
a few showers/thunderstorms, especially areas along the Blue Ridge
and west closer to remnant boundary and higher terrain. Again,
severe storms not expected. Highs low 80s.

High pressure builds further down the coastline Wednesday night
into Thursday, keeping area in light easterly flow. This will be
best chance for marine layer with potential for low clouds/fog
Wednesday night into Thursday morning before breaking Thursday
afternoon. Later on Thursday will also see gradual approach of
cold front from the west. Shower/thunderstorm chances again
highest west of the Blue Ridge and Allegheny Front with easterly
flow, terrain enhancement, and approaching front. High temps
Thursday will be dependent on cloud cover and extent of possible
marine layer but will show upper 70s to low 80s for now. Cold
front will be on the doorstep of the region by Friday morning.


A cold front will slowly pass through the area later Friday into
Friday night...bringing the chance for some showers and
thunderstorms. The best chance for convection will be during the
afternoon and evening hours. Seasonably warm and humid conditions
are expected ahead of the front with max temps in the 80s for most

Weak high pressure may briefly build into the area Saturday behind
the front. A couple showers and thunderstorms cannot be completely
ruled out...especially across central Virginia where there may be a
little more moisture. However...coverage will be limited and most
areas may end up dry and seasonably warm.

A stronger cold front will approach from the west Sunday before
passing through Sunday night into Monday. A southerly flow will
allow for warm and humid conditions ahead of the boundary...and this
will cause more instability. The instability will combine with
forcing from the front to trigger some showers and thunderstorms.
Some thunderstorms may contain gusty winds and hail along with
locally heavy rainfall.

Cooler and less humid conditions are expected behind the front early
next week...but an upper-level trough will build overhead during
this time. Most of the time should turn out dry due to the dry air
advection...but a couple showers cannot be completely ruled out due
to the upper-level trough overhead.


VFR expected area-wide for the remainder of the day. Could be an
isolated shower or thunderstorm near CHO but will leave out for
now due to low confidence/coverage.

Areas of fog possible again later tonight into Wednesday morning,
along with some isolated/scattered showers/thunderstorms Wednesday
afternoon, especially MRB/CHO. Sub- IFR conditions possible yet
again Wednesday night into Thursday with marine layer.

Winds generally less than 10 knots through Thursday, ranging from

Low clouds and patchy fog are expected early Friday...but cigs
should improve throughout the day. However...there will be a few
showers and thunderstorms that develop during the afternoon and
evening hours as a cold front moves through.

Drier air should move in behind the cold front overnight Friday and
Saturday...bringing vfr conditions to most of the terminals. There
still may be enough moisture for a popup shower/thunderstorm
Saturday afternoon in central Virginia near KCHO.

Another cold front will approach the terminals Sunday into Sunday
night. There is a better chance for thunderstorms ahead of this


Sub-SCA winds expected through at least Wednesday with surface
flow generally northeast to southeast less than 15 knots. Near-
SCA conditions possible Wednesday night into Thursday.

A cold front will pass through the waters late Friday into Friday
night. A few showers and thunderstorms are expected ahead of the
boundary. Weak high pressure may build in behind the front for
Saturday. The gradient should be weak enough for winds to remain
below sca criteria during most of this period.

There is a better chance for thunderstorms Sunday into Sunday night
ahead of an approaching cold front. Gradient winds may gust close to
sca criteria from the south during this time.




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