Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Baltimore Maryland/Washington District of Columbia
258 PM EDT sun Aug 30 2015
High pressure remains over the region through the end of the
Near term /tonight/...
Deep misture looks to remain over the Gulf states tonight and Monday...but
the middle Atlantic is xpcrng middle/high clouds out well ahead of a weak low
along the Georgia/Alabama brdr. The cloud cover has helped to keep temperatures down a
few degrees and limit lower level instability. Worst case scenario
would be isolated thunderstorms forming over the mountains late this aftn/eve.
Short term /Monday/...
Same pattern persists Monday. Highs will again range from the m80s to the
l90s. Isolated thunderstorms will be possible in the afternoon.
Long term /Monday night through Sunday/...
Sheared out vorticity maximum may linger over the area Monday evening...so
lingered slight chance probability of precipitation of a shower over the southern quarter or
so of the County Warning Area until midnight. Otherwise expect gradually clearing
skies. Lows in most areas middle to upper 60s...with 70s urban centers
and near shore.
Main story Tuesday will be the heat as middle and upper level ridging
build over the eastern Continental U.S.. lower elevation locations have at
least a chance of hitting 90...with middle 90s possible in the urban
corridor. Prognosticated dew points in the middle to perhaps upper 60s will
limit heat indices to a few degrees above air temperatures. As the
atmosphere appears to be capped...only have a small chance of
terrain-based convection in the far west. With little change in
airmass and mostly clear skies...lows Tuesday night should be close
On Wednesday...a shortwave trough aloft will be rounding the ridge
although there are some timing differences amongst the models. Middle-
level lapse rates will be steepening in the west...so there will be
a better chance of thunderstorms along and west of the Blue Ridge.
Uncertain at this time how much if any activity is able to spread to
the east. Highs may be slightly lower than Tuesday...especially in
the west...but upper 80s-lower 90s will still be supported for
Surface high pressure dominates through Friday but upper level disturbances
keep chances of afternoon showers and thunderstorms each day... with higher
chances west of the Blue Ridge. Temperatures will be 5 to 10 degrees
above normal between Thursday and Friday...m80s for the weekend.
Aviation /18z Sunday through Friday/...
VFR conds expeceted this evening through Monday.
VFR conditions and light winds prevail a majority of the time Monday
night through Wednesday. Only exception will be possible morning br
at cho/mrb. Wednesday afternoon will have a slightly higher
possibility of scattered thunderstorms...especially cho/mrb...with
less certainty for the metros.
VFR conditions expected Wednesday night into Thursday. Some showers and
thunderstorms possible Thursday afternoon.
Winds prntly below Small Craft Advisory values. Last evening there were hints that srly
channeling could lead to gusts 0f 20 knots...and that did happen for
several hours at tplm2 last evening. The WRF does not look quite as strong
for this evening...so will again hold and let the next shift keep an eye
on how things develop.
Winds expeceted to remain below Small Craft Advisory values during Monday.
Winds may increase with southerly channeling on the Bay Monday
evening...but at this time will leave forecast at 15 knots. Generally
light winds are then expected through Wednesday as high pressure
dominates. An isolated thunderstorm may reach the waters Wednesday
Sub-Small Craft Advisory conditions expected for Wednesday night into Thursday. Some showers
and thunderstorms possible Thursday afternoon.
District of Columbia...none.