Area Forecast Discussion
Issued by NWS Sterling, VA-- Remove Highlighting --
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FXUS61 KLWX 171903
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
303 PM EDT Sun Jul 17 2016
Weak high pressure will remain over the area through Monday
morning. A cold front will approach from the northwest late Monday
and cross the region on Tuesday. High pressure will build in
Wednesday and remain in place through Saturday. A cold front may
cross the region Sunday.
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Weak stationary front remains in the area but it continues to
dissipate. Heights continue to build and there are no disturbances
passing through over the next few hours. Thus...the suggestion of
isolated showers/t-storms over our southern zones for late this
afternoon into early this evening has not been included in the
forecast as believe it is a 10 percent probability event. That
having been said...with the front having not reached the
area...instability is present so something stray could pop up
based on instability alone. Otherwise...tonight will be mostly
clear after cumulus dissipates with lows in the 60s and lower 70s.
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
Things look more active on Monday but much uncertainty remains.
Front pushing southeast from Canada looks to move through early
Tuesday...a bad time if you want convection. What most likely
would happen is that storms well ahead of the front associated
with a weak leading shortwave may develop to our west and move
into our area towards evening on Monday before dying out or
diminishing to showers overnight. There is 25-35 knots of 0-6km
shear and decent CAPE...but also hints of a westerly flow which
may try to suppress convection. Bottom line...not alot of
confidence in potential thunderstorms on Monday aft/eve but
potential definitely exists especially in our NW zones. With the
SW to W flow ahead of the front, temps should spike into the mid
90s in our warmer locales. Heat indices should stay near or below
On Tuesday...any showers/storms depend on just how fast the front
moves through...as well as a push of drier air aloft. Right now
have them mostly in our southern zones...which makes sense given
expected frontal position. Temps will be on their way down.
Tuesday night into Wednesday...Canadian high pressure will provide
a cooler and drier air mass with sunshine. Lows in the 50s and 60s
with highs in the 70s and 80s.
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As high pressure remains in the area Thursday expect dry and
comfortable weather, with near seasonable temperatures (M/U 80s),
and relatively low humidity (dewpoints U50s/L60s).
We turn hot (highs in the M90s) but stay dry Friday. Though,
humidity gradually increases as southwest flow develops, which
will make it begin to feel slightly more uncomfortable.
Cold front then approaches the area next weekend. Still some
uncertainty with how far the front pushes through the area. Current
forecast has chance pops returning Saturday and Sunday afternoon
with front nearby and hot/humid atmosphere.
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
VFR and dry conditions through this evening. Some patchy fog
possible again Monday morning, but coverage will be much less than
this morning. Next chance of showers/thunderstorms will arrive
Monday afternoon through Tuesday with next frontal system.
Reductions below VFR possible along with potential for damaging
winds...best chance MRB. A stray storm may pop up Tuesday but odds
VFR conditions prevail Wednesday through Friday under high pressure.
Sub-SCA conditions expected through Monday morning across all
waters. Southerly flow increases tonight and into Monday with
marginal SCA conditions expected late Monday into Monday night
out ahead of next frontal system. Isolated to scattered
showers/thunderstorms also possible Monday into Tuesday. NW flow
behind front Tuesday-Tuesday night may also bring SCA conditions
with northerly channelling.
High pressure builds in Wednesday then remains through Thursday.
Winds should gradually increase Friday as southerly flow
redevelops over the area.
Anomalies are a little on the high side and should increase a bit
ahead of the next front. Sensitive sites (Annapolis) may briefly
reach minor thresholds on Monday.
MARINE...Small Craft Advisory from noon to 9 PM EDT Monday for