Area Forecast Discussion
Issued by NWS Sterling, VA
FXUS61 KLWX 181401
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1001 AM EDT Thu Aug 18 2016
A weak cold front will gradually move south of the area
through Friday before dissipating. Another cold front will cross
the area Sunday night. High pressure returns for the middle of
.NEAR TERM /THROUGH TONIGHT/...
Light showers this morning mainly south of the area along a
boundary extending east-west. To the north of the boundary, light
northwest flow injecting in slightly lower dew points. Highs will
also be on the slightly lower side, generally in the 80s across
the region with pockets of 90 near the DC metro. Enough
instability should still be lingering this afternoon that could
produce a stray shower or thunderstorm, mainly along the boundary
or due to terrain circulations.
Any convection will wane around sunset and dry conditions are
expected tonight. Min temps expected to reach the 60s west of the
Blue Ridge and low 70s east.
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
High pressure will be in place Friday. A disturbance is expected
to move across central/southern VA. Showers and thunderstorms are
possible mainly west of the I-95 corridor into Friday night. The
potential for showers and thunderstorms continues into Saturday
night as westerly flow aloft drives disturbances near the region.
At this time...coverage looks isolated to scattered with the best
chance being in the afternoon and early evening hours.
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
A deepening trough over the upper MS valley Sun will track ewd
across the Great Lks Sun night and Mon. This will help push a
strong cdfnt through the area Sun evening. Moisture and
instability surges ahead of the front Sun with showers and
t-storms expected Sun afternoon and evening. Latest GFS seems to
be significantly downplaying the precip potential across the area
given 2.0+ PWATs, high CAPE and wave of low pressure expected to
form. The latest Euro looks more reasonable and shows average
rainfall amounts of 0.25 to 0.5 inches over VA with amounts upward
of 1-2 inches over northeast MD. Although this front looks fairly
progressive, think there are enough ingredients now for a flash
flooding threat particularly over northeast MD. Also, the threat
looks higher than with the rainfall event last evening. There
might be a severe wx threat also near the track of the low. The
front clears the area faster now with precip shifting east of the
Ches Bay late Sun night. High pressure then builds for next week
with temperatures returning to normal in the mid 80s.
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
Generally VFR conditions for the TAF period. Isolated
showers/thunderstorms possible, mainly KCHO/KMRB/KIAD this
afternoon and then again Friday afternoon.
Possible flying restrictions Sun afternoon and evening with
showers and possible t-storms as a cdfnt moves through the area.
Gusty NW winds Mon and Tue behind cdfnt.
Sub-SCA conditions with west winds will continue on the waters
today. An isolated shower or thunderstorm is possible this
W to NW flow will continue through Friday, generally 10 kt or less.
A stray storm can`t be ruled out on southern waters. No marine
hazards expected through Saturday.
Small craft advisory conditions are likely Mon into Tue behind a