Area Forecast Discussion
Issued by NWS Sterling, VA
FXUS61 KLWX 280124
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
924 PM EDT Thu Apr 27 2017
A weak cold front crosses the area from the west tonight. High
pressure over the area Friday, then dropping off the southeast
coast Saturday. A cold front will move over Pennsylvania
Saturday night before lifting north. A cold front will move
through the region from the west Monday night. Canadian high
pressure will then build over the area through the middle of
.NEAR TERM /THROUGH tonight/...
As of 9pm, two clusters of prefrontal showers and thunderstorms
continue to shift northeast from the eastern WV panhandle and
central VA. Low level CIN will continue to repress original
growth. Elevated CAPE of a few hundred j/kg and bulk shear of 45
knots allows ongoing activity to continue.
Actual front is back over wrn WV and will continue to slowly
push east. Despite good bulk shear, early prefrontal activity
and a nocturnal trend should gradually reduce this activity with
little expected east of the Allegheny Front.
Lows ranging from the upper 40s in the Highlands to the mid 60s
in the cities. Much of inland areas will drop to 60F.
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
Weak front will move offshore Friday morning. Light fog is
possible but not expected to be as dense/widespread as previous
We will be in a warming trend heading into the weekend as high
pressure strengthens off the SC coast. This will pump warm air
into the Mid Atlantic, and by Saturday temperatures will have a
decent shot at topping 90.
The record temperatures for April 29 - we`ll be close to these
Highs max High min
DCA 91 68
BWI 91 67
IAD 87 62
.LONG TERM /SUNDAY THROUGH THURSDAY/...
High pressure to the southeast will break down with a warm front
sliding northward across the D.C. area Sunday into Sunday night.
There is a chance for showers and a thunderstorm, mainly Sunday with
the warm front nearby.
An increasing southerly wind will usher in warmer and more humid air
to help fuel showers and thunderstorms, mainly Monday afternoon and
evening ahead of a strong cold front. A few thunderstorms could
contain strong winds.
Gusty westerly winds and drier and cooler air will filter into the
region Tuesday and Tuesday night behind the cold front as high
pressure builds in from the west.
High pressure moves offshore Wednesday, while keeping conditions
dry. A return flow will be an indication that a new warm front will
try to push across the region late Wednesday into Thursday.
The Thursday storm system that is expected to develop along the warm
front could intensify over the Ohio Valley before sending energy
eastward into the mid-Atlantic later in the day Thursday.
.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
VFR through the afternoon/early evening. Isolated showers and
thunderstorms will be possible at TAF sites this evening. These
are expected to weaken while progressing east of the mountains.
Light fog possible Friday morning then VFR at all sites Friday
into Saturday. Front lingers just north of the DC metros
Saturday into Sunday. A backdoor cold front is now expected to
be contained Mason-Dixon line and north Saturday night.
Mvfr to ifr conditions expected Sunday and Sunday night with showers
and a thunderstorm in the area near MRB, IAD, MTN and BWI terminals.
Vfr conditions elsewhere. Ifr to lifr conditions Monday and Monday
night with showers and thunderstorms. Winds east 5 to 10 knots
Sunday, southerly 5 to 10 knots Sunday night, then southwest 10 to
15 knots Monday, and southwest 10 knots Monday night.
SCA for southerly channeling into the overnight, will continue
until a cold front over West Virginia crosses the waters. Light
NWly flow behind the cold front Friday morning, becoming
southerly Friday afternoon.
A front lingers north of the waters Friday night through
Saturday night with south flow continuing from a Bermuda high.
No marine hazards expected Sunday and Sunday night. Small craft
advisories possible Monday and Monday night. Winds east 10 knots
Sunday, southeast 10 knots Sunday night, increasing southwest 15
knots gusts 20 knots Monday, and southwest 10 to 15 knots Monday
South flow has maintained water levels around three quarters of
a foot above normal. This is enough to reach minor coastal
flooding on the preferred high tide late tonight at Straits
Point in St. Marys County.
Annapolis will continue to be monitored as it will also approach
minor coastal flooding late tonight as well.
MD...Coastal Flood Advisory from 1 AM to 6 AM EDT Friday for MDZ017.
MARINE...Small Craft Advisory until 5 AM EDT Friday for ANZ531>534-537-