Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Baltimore Maryland/Washington District of Columbia
1022 am EST sun Feb 14 2016

Synopsis...
Arctic high pressure overhead this afternoon will move off to the
east tonight. Low pressure will impact the region Monday through
Tuesday bringing significant wintry precipitation. High pressure
builds for the middle and latter part of the week.

&&

Near term /through tonight/...
high pressure will persist across the region today. High and middle-
level clouds will increase this afternoon ahead of low pressure
over the central Continental U.S.. temperatures will only climb into the 20s and
teens in the mountains high pressure slowly moves offshore tonight and
a light southerly wind will begin into Monday morning.

An upper-level disturbance in the westerly flow aloft will move
into the region late tonight. Low pressure will begin to develop
over the Gulf Coast states during this time. Warm and moist air
will overrun the cold air in place...causing snow to break out
overnight. Accumulating snow is likely across central Virginia
into the Potomac Highlands...and possibly into the Washington
metropolitan area and southern Maryland by daybreak.

&&

Short term /Monday through Tuesday/...
low pressure will continue to develop across the Mississippi
Valley Monday and a warm front aloft will approach from the South.
Strong warm air advection aloft will cause snow to move north and
east into Monday morning as warm air advection continues. Forecast
soundings show warm air advection causing temperatures aloft to become above freezing as
early as Monday afternoon and therefore snow is expected to change
to sleet from southeast to northwest into Monday evening. Surface
temperatures will only rise to around 30 degrees Monday afternoon before
staying steady into Monday night. The surface warm front will have a
hard time moving northward Monday night into Tuesday even though
GFS/European model (ecmwf) have it crossing the region. The Wedge of high pressure
in place and light boundary layer winds seem to hang on to the
cold air much longer than low resolution models portray. Based on
climatology kept temperatures cooler than guidance.

Any snow and sleet will transition to freezing rain Monday night as
warm air advection continues and the warm nose aloft lowers to the surface. Low
pressure will move into the Ohio Valley late Monday night and with
it...a slug of moisture is expected to move from west to east across
the middle-Atlantic region into Tuesday morning. The warm front will
likely move slowly into the region from the southeast and temperatures will
begin to go above freezing during the day Tuesday. Temperatures at higher
elevations will also become above freezing by Tuesday morning. The
warm front will likely reach northern Maryland and the Potomac Highlands by
late Tuesday morning into the afternoon. The combination of snow and
ice will lead to treacherous travel conditions for areas along and
west of the Blue Ridge mountains and therefore a Winter Storm Warning was
issued. Ice and snow conditions for this area of concern include
0.25 inch of ice accumulation on top of multiple inches of snow.
Snowfall accumulation will range from 4-8 inches across the SW County Warning Area
to 3-6 along and west of the Blue Ridge mountains further east...the
potential for 1-3 inches of snow and a tenth of an inch of ice is
forecast.

Low pressure rapidly moves into New York state Tuesday afternoon and
precipitation should end with the exception of a few rain or snow
showers along the western slopes of the mountains

&&

Long term /Tuesday night through Saturday/...
mainly dry weather through the end of the week as high pressure
builds. Some upslope precipitation will continue through Wednesday in the
Potomac Highlands then drying. Cooler weather returns Tuesday night through
Thursday then warming up for next weekend as high pressure slides offshore
and winds turn more southwesterly.

&&

Aviation /15z Sunday through Thursday/...
VFR conditions expected through this evening. Snow is expected to
move into the region from SW to NE late tonight and continue
Monday. Ceiling and visibility restrictions are expected due to snow. Winds
will stay under 10 kts and should not pose a threat to blsn.

Snow transitions to pl/freezing rain Monday afternoon into Tuesday morning.
Precipitation may be heavy at times and flight restrictions are expected.

Improving conditions Tuesday night through the end of the week.

&&

Marine...
high pressure will build over the waters tonight. A Small Craft
Advisory is still in effect...but winds will continue to diminish
into tonight. Low pressure will likely impact the waters later
Monday into Tuesday.

No marine hazards expected Tuesday night and Wednesday.

Small craft conditions likely through Thursday.

&&

Tides/coastal flooding...
blowout tides occurring at this time. Winds diminish tonight with
tides returning to normal. Strong srly surge expected Monday night
with water levels rising. Minor coastal flooding possible at
sensitive locations Tuesday.

&&

Lwx watches/warnings/advisories...
District of Columbia...none.
Maryland...Winter Storm Warning from 1 am Monday to 10 am EST Tuesday for
mdz003-004-501-502.
Winter Storm Watch from late tonight through Tuesday morning
for mdz005-503>505.
Virginia...Winter Storm Warning from 9 PM this evening to 10 am EST
Tuesday for vaz025>027-029-030-036-037-503-504-507-508.
Winter Storm Warning from 1 am Monday to 10 am EST Tuesday for
vaz028-031-038>040-501-505.
Winter Storm Watch from late tonight through Tuesday morning
for vaz050>053-055-056-502-506.
WV...Winter Storm Warning from 9 PM this evening to 10 am EST
Tuesday for wvz055-501-502-505-506.
Winter Storm Warning from 1 am Monday to 10 am EST Tuesday for
wvz050>053-503-504.
Marine...Small Craft Advisory until 1 PM EST this afternoon for
anz530>543.

&&

$$
Synopsis...lfr
near term...bjl/has
short term...bjl/has
long term...lfr
aviation...bjl/has/lfr
marine...bjl/has/lfr
tides/coastal flooding...lfr

National Weather Service Glossary of Abbreviations