Area Forecast Discussion
Issued by NWS Sterling, VA
FXUS61 KLWX 200041
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
841 PM EDT Sun Mar 19 2017
High pressure builds 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 /UNTIL 6 AM MONDAY MORNING/...
Relatively quiet weather overnight as southward-moving high
pressure that is currently situated over Ohio slides through
Lows tonight dropping into the low 30s. Some localized fog is
possible...should areas fully decouple and skies clear. High-
resolution ensemble guidance (e.g., NARRE/HREF) suggests the
best possibility for this would be across central/eastern
MD...though it is currently low probability.
.SHORT TERM /6 AM MONDAY MORNING 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 /01Z MONDAY 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...localized fog is possible.
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
diminish through tonight as low pressure off the Delmarva
drifts further east. SCA possible Tuesday as high pressure
builds with north winds.
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 2 AM EDT Monday for ANZ530>532-536-
Small Craft Advisory until 6 AM EDT Monday for ANZ533-534-537-