Scientific Forecaster Discussion
Area forecast discussion...corrected
National Weather Service Baltimore Maryland/Washington District of Columbia
936 PM EDT Monday Aug 3 2015
a cold front will gradually push southeast into the area tonight
and Tuesday. The front will slide south of the area Tuesday night
allowing high pressure to build in Wednesday. The front will push
back north into the area on Thursday as a wave of low pressure
rides eastward along it. This low will clear the area Friday
taking the front with it. High pressure will build in behind it
and dominate over the weekend.
Near term /through Tuesday/...
storms over scntrl PA have pretty much dissipated. Other storms
over western PA expected to track mainly east and stay well north. It
doesn't look like we'll see anything overnight but kept slight
chance along the Mason Dixon line and over the Potomac Highlands.
Cold front will cross the area tomorrow but it will slow down. It
appears storms could fire over southern Maryland Tuesday afternoon. Storm Prediction Center has this
area highlighted under slight risk of severe storms.
Short term /Tuesday night through Thursday/...
high pressure will move into the central Appalachians Tuesday
night and shift slowly east from there...reaching the District of Columbia metropolitan
Thursday morning. Temperatures Wednesday will be a few degrees
cooler and dew points will drop into the upper 50s in many areas.
Sunshine will also predominate Wednesday...but an approaching
wave of low pressure to the west will cause clouds to increase by
Thursday morning. As this wave approaches during the day
Thursday...rain showers and possibly some thunderstorms will begin
to encroach from west to east. Clouds will tend to keep
temperatures slightly cooler on Thursday but dew points will rise
back into the middle 60s in much of the area.
Long term /Thursday night through Monday/...
models are in much better agreement in terms of the timing of a
wave of low pressure Thursday night into Friday...however the
track and strength still differs from model to model and run to
run. Felt confident enough to go with likely probability of precipitation across most of
the area Thursday night into Friday in a pseudo warm air advection
pattern. Convective potential will depend on if the low pressure
area passes north or south of the area.
The low will pass east and out to sea...likely bringing the front
with it by the weekend. High pressure should return over the
weekend...before another system approaches by early next week.
Aviation /02z Tuesday through Saturday/...
VFR tonight and Tuesday. Some storms could fire southeast of District of Columbia Tuesday
afternoon but odds seem low at this time for any of the terminals to get
VFR Tuesday night-Thursday morning all terminals as high pressure builds
in. Winds fairly light.
Sub-VFR likely in rain showers/isolated thunderstorms and rain Thursday after-Friday as low pressure moves
across. Wind speed/direction forecast uncertain with low moving
very near the area. VFR should return along west/ northwesterly flow around 10
Marine...winds have subsided on the waters but models show winds
strengthening overnight over the Lower-Middle Bay due to srly
channeling. Modified Small Craft Advisory to remove middle and upper Potomac. Winds
could gust to Small Craft Advisory Upper Bay north of Pooles Island Tuesday afternoon.
Small Craft Advisory may be needed for that area.
Sub Small Craft Advisory winds with dry conditions Tuesday night-Thursday morning under
Wind forecast over the waters is highly uncertain Thursday after
through Friday due to low pressure passing very near or overhead.
However...some gusts in southerly channeling are possible across
portions of the waters...especially if the low track passes
further north. Showers and isolated thunderstorms are also likely
over the waters Thursday night into Friday.
District of Columbia...none.
Marine...Small Craft Advisory until noon EDT Tuesday for anz532>534-537-