Area Forecast Discussion
Issued by NWS Sterling, VA
FXUS61 KLWX 221839
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
239 PM EDT Mon Aug 22 2016
High pressure will build eastward from the Ohio Valley today. The
high will gradually shift eastward though the week ahead before a
cold front crosses the area on Friday. High pressure behind that
front will dominate through the weekend.
.NEAR TERM /THROUGH TONIGHT/...
High pressure still over the Ohio Valley this afternoon. Cumulus
clouds have developed in daytime heating, but with very little
vertical extent. Also still have some gusts in the mid teens. They
have outlived the window offered by model guidance, so have to
believe that the gradient will relax soon.
The center of the high willl drift toward the area tonight. Guidance
suggesting that some moisture may get trapped under subsidence
inversion. Am still not stressing that solution too heavlily, but it
will be something to focus upon. If it happens, low temperatures
will be warmer. For that reason, did not emphasize radiational
cooling too much.
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
Transitory high pressure will be the focus for Tuesday and
Wednesday. Expect benign conditions for the midweek. By Wednesday,
we will begin to see return flow, so dewpoints (and temperatures)
will start to creep upward by Wednesday. It will still be seasonably
.LONG TERM /THURSDAY THROUGH MONDAY/...
High pressure slides off the coast on Thursday as a cold front
approaches Thursday night. Some showers could develop ahead of the
front, mainly over our western counties. Main showers and
thunderstorms activity expected Friday as cold front moves across
our CWA. The front will slowly moves south Saturday into Sunday as
high pressure builds in, bringing cooler and drier weather.
Surface easterly flow could enhance some afternoon shower and
thunderstorm activity on Sunday, mainly west of the Blue Ridge.
Dry conditions expected on Monday as high pressures moves across
the Mid-Atlantic and off the coast. High temperatures will be in
the upper 80s and low 90s... with Friday having the highest heat
indexes in the upper 90s.
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
VFR through Wednesday. Guidance suggesting that the current cumulus
may lead to clouds trapped under a subsidence inversion. Even if
that were to transpire, ceilings would be FL050. At this time, am
still not forecasting this solution.
Showers and thunderstorms possible on Friday causing sub-VFR
conditions. Mainly VFR conditions expected Saturday.
Pressure gradient has held on. As a result, have had wind gusts in
the mid teens, with occasional gusts close to Advisory criteria.
Have been allowing SCA to expire on time; the last piece will drop
Light winds tonight and tomorrow morning has high pressure passes
overhead. South winds for Tuesday afternoon through Wednesday.
However, do not believe that winds will be too much above 10 kt.
Sub-SCA conditions expected between Thursday and Sunday with wind
gusts below 15 kt. Some showers and thunderstorms possible on
MARINE...Small Craft Advisory until 3 PM EDT this afternoon for ANZ534-