Area Forecast Discussion
Issued by NWS Sterling, VA
FXUS61 KLWX 191855
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
255 PM EDT Sun Mar 19 2017
High pressure will build over the area into Monday, before weak
low pressure crosses the area Monday night. A cold front crosses
the area Tuesday night with Canadian high pressure then building
over the Mid-Atlantic into Thursday. A warmup is then expected
into the weekend.
.NEAR TERM /THROUGH TONIGHT/...
As of 2pm, an upper level trough is apparent in GOES water vapor
imagery off the Mid-Atlantic coast. 1029mb surface high
pressure is centered over MI/OH. The high will shift to the
Carolinas through tonight while the low drifts east. Clearing
skies through tonight as dry air from the northeast shifts south
over the area. Clouds have suppressed the wind over the area,
but some gusts around 20 mph are expected for the rest of the
Min temps tonight low 30s with dewpoints dropping into the upper
20s to near 30F. Should areas decouple, some fog is possible.
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
High pressure ridge shifts south from the area Monday with
light/variable flow becoming southerly. Sunny at sunrise with
increasing high clouds ahead of an approaching shortwave trough.
Max temps mid to upper 50s - near normal (only the second at or
above normal in the past 10 days).
A shortwave crosses the area Monday evening/into the overnight
with a quick round of rain showers across the area and one to
two tenths inch qpf.
Subarctic cold front approaches Tuesday with another shortwave
crossing the area Tuesday night with the cold front. Rain
changes to snow on the northern fringe of precip and in the
mountains. Some more elevation dependent light snow
accumulations are possible by Wednesday morning.
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
An area of strong high pressure will build southward from the Great
Lakes Wednesday through Thursday night. Drier air and colder
temperatures will be ushered into the region.
This high pressure will move to the coast Friday and Friday night to
allow for a return flow and milder air to develop for the mid-
A cold front will sag across the Eastern Great Lakes Saturday and
Saturday night, possibly reaching the Mason-Dixon line later
Saturday night. A chance for rain showers will develop during this
The chance for rain showers linger on Sunday as a warm front
connects to the tail-end of the cold front and a disturbance follows
along the Ohio Valley.
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
VFR conditions prevail through Wednesday as low pressure moves
east of the area and surface high pressure builds in from the
west. Skies clear tonight and in areas that the wind calms fog
Rain showers Monday night from a weak low and then another low
along a subarctic cold front Tuesday night will have rain
possibly ending as snow.
Vfr conditions Wednesday through Thursday night. Winds northwest 10
to 15 knots gusts 20 to 25 knots Wednesday. Winds becoming north 5
to 10 knots Wednesday night. Winds light and variable Thursday,
becoming south 5 knots Thursday night.
SCA force north winds (gusting around 20 knots) slowly
diminishes through tonight as low pressure off the Delmarva
drift east. SCA possible Tuesday as high pressure builds with
A strong cold front crosses the area Tuesday night with SCAs
starting that night.
At least small craft advisories Wednesday as a subarctic cold
front crosses the area. Small craft advisories possible into
Thursday. No marine hazards Thursday and Thursday night. Winds
northwest 15 knots gusts 25 to 30 knots Wednesday. Winds
becoming north 10 to 15 knots gusts up to 20 knots Wednesday
night. Winds diminishing Thursday. Winds becoming south 5 to 10
knots Thursday night.
MARINE...Small Craft Advisory until 6 PM EDT this evening for ANZ530-
Small Craft Advisory until 6 AM EDT Monday for ANZ533-534-537-
Small Craft Advisory until 2 AM EDT Monday for ANZ532-536-540-