Area Forecast Discussion
Issued by NWS Sterling, VA
FXUS61 KLWX 160745
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
345 AM EDT Thu Mar 16 2017
.SYNOPSIS...High pressure will gradually build east from the
mid-Mississippi valley through early Friday. A cold front will
move through the area Saturday. High pressure builds over the
area for the second half of the weekend into early next week.
.NEAR TERM /THROUGH TONIGHT/...A 1030mb high is located across the
mid-Mississippi River Valley this morning while low pressure
continues to move north of New England. Northwest flow is across
the region however the pressure gradient has relaxed since
Wednesday. Gusty winds and cold temperatures have resulted in
sub zero wind chills across the higher elevations overnight. A
wind chill advisory will continue this morning for the Allegheny
Front, Blue Ridge mtns and higher elevations between.
Another chilly day expected for the Mid-Atlantic region with
temperatures well below normal. Northwest winds will increase by
afternoon however gusts will stay below 30 mph today. Temps will
range from the L30s to L40s and 20s in the mtns. Upslope snow
showers will come to an end by afternoon. Showers have been light
High pressure moves to the south tonight. Clear and cold
conditions are expected tonight with temps dropping into the
20s and teens in the mtns.
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...High pressure over the
SE US will move to the east Friday and southerly flow will
begin. A warm front will approach the region from the west
Friday morning and mid-high level clouds will increase. Temps
will climb into the 40s by Friday afternoon with some places
across the Piedmont seeing 50. Warm air advection aloft will
move into the region Friday and rain is expected to move from
west to east through the afternoon. As a warm front approaches
Friday night temperatures are going to slowly drop or stay
steady into Saturday morning. At this time temps look to stay
above freezing however the potential exists for temps to drop
near freezing mainly across the Allegheny Front and far northern
MD. Due to the warm air aloft...fzra can not be ruled out
across these areas. Although fzra in March is difficult in the
Mid-Atlantic, the recent cold snap may keep the ground cold
enough for some impact. At this time confidence is low that
temperatures will drop to sub- freezing.
A cold front will move across the region Saturday. Guidance
indicates low pressure developing along the front. Rain is possible
across the region however there will likely be a lull across the
outlook area with better forcing to the south and east. Northwest
flow will increase behind the departing low Saturday and upslope
snow showers will begin and continue through Saturday night.
Accumulation of 1-2 inches is possible along the Allegheny Front
during this time.
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...Cool and breezy conditions
expected Sunday as low pressure moves farther away from the
coast. Chilly Sun night as sfc ridge builds and winds diminish.
A weak cdfnt moving through the eastern Great Lks Mon will bring
a chance of rain showers Mon and Mon night. Some notable
differences are seen with timing of that frontal passage between
latest GFS and ECMWF models which could result in showers
persisting through Tuesday. By the middle of next week, high
pressure will be building into the region from the upper midwest
with seasonably cool and dry conditions expected.
.AVIATION /08Z THURSDAY THROUGH MONDAY/...VFR conditions
expected through Friday. NW winds 12-18 G25 kts expected today
with lighter winds at CHO. Northwest winds will continue through
tonight. Mid-high level clouds move into the region tonight and
rain is likely Friday into Friday night. Reduced cigs are
possible into Saturday morning. A cold front will cross the
region Saturday. NW increase again.
Gusty NW winds expected Sun diminishing Sun night.
.MARINE...Northwest winds will continue today. A Small Craft Advisory is in
effect today for all waters. Winds will gradually subside further
tonight into Friday. A Small Craft Advisory is in effect for
portions of the waters tonight. A warm front will pass through the
waters Friday night. Rain is likely Fri-Saturday. A cold front will
cross the waters Saturday. NW winds increase again Sat-Sat night.
SCA are likely during this time.
SCA conditions likely Sun-Sun night.
.CLIMATE...Record low maximum temperatures were set at IAD and
BWI yesterday. See RERs for those two airports.
MD...Wind Chill Advisory until 10 AM EDT this morning for MDZ501.
VA...Wind Chill Advisory until 10 AM EDT this morning for VAZ025-
WV...Wind Chill Advisory until 10 AM EDT this morning for WVZ501-
MARINE...Small Craft Advisory until 6 AM EDT Friday for ANZ530>534-537-
Small Craft Advisory until 8 PM EDT this evening for ANZ535-