Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 310735

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

A frontal boundary will remain near the region through Thursday
night. A cold front will pass through from the west later Friday
into Friday night. High pressure may briefly build into the area
Saturday before a stronger cold approaches Sunday before passing
through Sunday night into Monday.


Weak boundary, barely noticeable except for weak wind shift and
slight decrease in dew points, will continue sinking southward
through the region this morning. Have seen areas of fog develop,
and these will continue through the early morning hours until it
lifts and dissipates after sunrise. Otherwise, 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, but should largely stay north of the region and wash out
as it propagates southward. May re-inforce light northeast flow as
it does so. Some hi-res guidance does try to bring a few
showers/storms towards western/northern Maryland along boundary,
so have placed in some slight chance POPs there for a few hours
this evening. Otherwise a generally quiet night 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.


A variety of flight categories early this morning with areas of
IFR or lower conditions in low clouds and fog. Will see these
conditions break after sunrise with 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

Additional 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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