Area Forecast Discussion
Issued by NWS Sterling, VA
FXUS61 KLWX 270137
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
937 PM EDT Wed Apr 26 2017
Low pressure east of New Jersey will continue to slowly move
northeast through tonight. A weak cold front cross the area from
the west Thursday night. A backdoor front will move west across
the area Saturday night into Sunday before lifting north as a
warm front early Monday. A stronger cold front will move through
the region from the west Monday night.
.NEAR TERM /THROUGH Tonight/...
As of 9pm, there is a weak surface ridge extending from off the
mouth of the Chesapeake Bay to to roughly Dulles and south of
the low off the NJ shore. Light SE flow is across the CWA. A
swath of low clouds persists over the Baltimore metro area.
Northeastern sections of the area should see an increase in low
level clouds through the night with patchy fog. West of there to
the Blue Ridge, expect radiational fog to develop overnight in
the clear and calming conditions.
Min temps mid to uppers 50s inland to around 60F in urban
centers per ER Superblend.
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
After the low pressure area finally departs and moves east of
Cape Cod Thursday skies should finally return to a mostly sunny
condition - after morning fog/low clouds.
South winds begin to mix after 10am with gusts 20 to 25 mph
across the area through the afternoon. Well mixed 14C 850mb
temps should result in low to mid 80s maxima.
But the respite from clouds will be short. A weakening cold
front will be pushing into the Mid Atlantic Thursday night
bringing the chance of showers/isolated thunderstorms. This will
not be coming through at a prime time for severe weather.
Coverage will be spotty, so one place could pick up a few tenths
of an inch of rain while ten miles away stays dry.
The front is expected to be east of the region by Friday
morning. Skies should improve, highs again in the lower to mid
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
High pressure will be to our southeast with a front along the Mason-
Dixon line Saturday and Saturday night. Temperatures will remain
warm with a chance of showers or a thunderstorm mainly across the
northern half of our region.
By Sunday into Sunday night, the high to the southeast will break
down with the front sliding across the D.C. area during the day
before meandering northward as a warm front Sunday night. The chance
for showers and thunderstorms will become more prominent,
mainly Sunday with the front nearby and before the warm surge.
An increasing southerly wind will usher in warmer and more humid air
to help fuel showers and thunderstorms Monday into Monday evening. A
strong cold front should works its way eastward across the region
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 later Wednesday.
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
MVFR cigs persists in the Baltimore metro...VFR elsewhere rest
of the evening. Fog/low stratus development expected overnight.
Still left visibilities in the 2-3SM range given potential
presence of low clouds generally 08Z-14Z.
VFR after 13-14Z Thursday with increasing southerly flow. Gusts
20 to 25 kt expected through the afternoon. Showers/isolated
thunderstorms possible Thursday night as a weakening cold front
moves through. VFR again Friday.
Mvfr to ifr conditions expected Saturday through Sunday with showers
and thunderstorms in the area near MRB, IAD, MTN and BWI terminals.
Vfr conditions elsewhere. Mvfr to perhaps vfr conditions Sunday
night. Winds southwest around 5 knots Saturday, becoming light and
variable Saturday night, then east 5 to 10 knots Sunday, and
southerly 5 to 10 knots Sunday night.
Winds expected to remain below SCA values through tonight. Southerly
flow increases through Thursday with 20 knot gusts warranting a
small craft advisory from noon to midnight. Showers/isolated
thunderstorms will be possible Thursday night as a weak cold
front enters the Bay region. Southerly channeling ahead of this
front warrants a continued SCA until 5 am Friday.
No marine hazards expected Saturday through Sunday night. Winds
southwest 5 to 10 knots Saturday, becoming light and variable
Saturday night, then east 10 knots Sunday, and southeast 10 knots
Water levels have decreased slightly with northwest winds today but
remain elevated, especially from the Potomac River southward.
Straits Point will exceed minor flood stage through at least the
overnight high tide cycle. Guidance shows steady to decreasing
waters for the remainder of the week, but am a bit skeptical
about this outcome considering winds will become south or
southwesterly through that time. Thus minor flooding at
sensitive sites will need to continue to be monitored. In terms
of the current guidance, Friday morning will be the next
MD...Coastal Flood Advisory until 6 AM EDT Thursday for MDZ017.
MARINE...Small Craft Advisory from noon Thursday to 5 AM EDT Friday for
Small Craft Advisory from noon Thursday to midnight EDT
Thursday night for ANZ530-535-536-538-542.