Area Forecast Discussion
Issued by NWS Sterling, VA
FXUS61 KLWX 200431
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1231 AM EDT Tue Sep 20 2016
High pressure will build over the region tonight through
Thursday. A dry cold front will move through the area Saturday
afternoon bringing fall like weather.
.NEAR TERM /THROUGH TODAY/...
Tidal section below updated.
Mostly dry conditions expected across the Mid-Atlantic region
tonight. Isolated showers are possible overnight as an upper
level low moves off the southeast coast. Rainfall amounts will be
Clearing has occurred across the Appalachians...Potomac Highlands
and Shenandoah Valley this evening. Due to recent rain...fog is
expected to form overnight. There has been some clearing east of
the Blue Ridge as well and some fog has formed across the Central
Foothills. This will continue tonight however northeast flow in
the low levels will keep a constant moisture feed into the Mid-
Atlantic overnight and low clouds are expected to form east of the
Blue Ridge mountains as well as portions of the Potomac Highlands
overnight into Tuesday morning.
The upper level low will continue to rotate over the southeast U.S
Tuesday. A stationary front will be along the coast and showers
are possible across the Central Foothills and south of Washington
DC mainly in the afternoon. Winds will stay out of the northeast
with temps reaching around 80 deg.
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
High pressure will gradually build over the mid-Atlc through Thu
leading to drying conditions. The only exception is over St. Marys
county where showers could persist along weak confluence zone.
Model soundings suggest potential for widespread fog Tue and Wed
nights as mid- level subsidence builds in and ground remains moist
from today`s rains.
.LONG TERM /THURSDAY THROUGH MONDAY/...
Fairly benign weather pattern late this week and into the weekend
as high pressure lingers nearby and precipitation chances remain
minimal. Above normal temperatures (with some humidity) forecast
through Saturday. Cold front expected this weekend...which will
help to lower temperatures and dewpoints as high pressure builds
into the area from the north. Limited moisture with frontal
boundary looks to keep precip chances rather low.
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
Fog and low stratus expected tonight. VFR conditions will become
MVFR/IFR overnight and into Tuesday morning at all terminals. Low
confidence at the exact time of MVFR/IFR tonight however it should
stay around until 13-15z Tuesday.
Fog appears likely at KMRB and KCHO overnight where skies are
likely to clear out at some point during the night. Over eastern
terminals, low clouds/cigs with no VSBY restrictions appear more
likely where mid and high level clouds are expected to be hang on.
Potential for more widespread fog Tue and Wed nights.
VFR conditions expected Thursday through early this weekend.
NEly flow then through Tuesday generally 10 kt.
High pressure builds in from eastern Great Lakes Tuesday and
Wednesday with north winds.
Winds expected to remain below SCA values Thursday and Friday.
No coastal flood headlines as of now. Northeast winds continue on
the waters through Tuesday as low pressure remains along the
Carolina coast. However, anomalies will stay elevated and near
action stages into Wednesday. Water levels will continue to be