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000
FXUS61 KLWX 200850
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
350 AM EST Wed Feb 20 2019

.SYNOPSIS...Low pressure will track from the Mississippi valley
into the Great Lakes today through tonight. Coastal low
pressure will develop along the Mid-Atlantic Coast tonight
before moving off to our northeast Thursday. High pressure will
return Thursday night and Friday before another low pressure
impacts the area early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...

WAA overrunning snow has begun across our southwest with snow
now being reported as far north as Opal VA and Petersburg WV.
Upstream reports across west central VA (Roanoke area) indicate
a 4-hr period of heavy snow with an inch per hour snowfall
rates with snow having transitioned to sleet and freezing
drizzle in that area. Expect snow to continue to develop
northeast later this morning with snow transitioning to fzra/pl
after 12Z in the Charlottesville area and across northern VA and
DC around midday and the rest of the CWA by 21Z as warm nose
lifts northward. Then, freezing rain/rain in the late afternoon
and early evening becoming all rain everywhere by midnight
tonight. Expect generally 3-6 inches of snow in the warning area
with higher snow totals of 6-8 across northern and western MD
and significant icing across northwestern VA, eastern WV, and
western MD roughly west of Rt 15 and north of Rt 33 in
Harrisonburg.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...

Cdfnt clears the area early on Thu with rain ending by 09Z if
not sooner. High pressure then builds over the area Thu night
with next round of overrunning precip associated with developing
southern Plains cyclone beginning late Fri night. Given milder
period ahead and high pressure at a more eastward position, this
appears to be a mostly rain event except possibly in far NW
Maryland where some freezing rain is possible.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...

Warm front will be crossing the area Saturday, with more than enough
isentropic lift to induce a swath of precipitation. Thermal profiles
will be sufficiently warm for this to be all rain. With a trajectory
off of the Gulf of Mexico, anticipate that moisture won`t be a
hinderance. Model guidance suggesting precipitable water will be
exceeding an inch...and approaching an impressive (for February) 1.5
inches by Saturday night. Any remaining snow should be melted away,
as temperatures drop little Saturday night in continued warm
advection. But, the rainfall and snowmelt could lead to flooding
concerns, as suggested by the NAEFS MMERF.

Temperatures will continue to rise well into the 60s on Sunday ahead
of a cold front, which may lead to additional showers. A tight
thermal gradient should lead to strong cold advection, and thus
windy conditions.

High pressure will build across the northeast Monday-Tuesday. Since
broad ridging remains 850-500 mb, temperatures don`t drop
considerably...and will remains at or above climo normals Monday,
receding to near normal by Tuesday. (Cold advection/breezy
conditions will continue into Monday.) With a jetmax along the
central Atlantic coast, systems will be progressive. Chance PoPs
will return by the end of the day Tuesday.

&&

.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...

Developing LIFR/IFR conditions this morning as snow develops. A
4-hr period of heavy snow is expected with intense snowfall
rates of 1+ inch per hour is likely mainly in the 11Z-17Z time
frame. Then, snow changing to sleet and freezing rain in the
afternoon and eventually to rain late today or early this
evening. KMRB will be the last to change to rain not likely
until 03Z tonight. Rain ends late tonight around 09Z with cigs
and vsbys improving.

Flight restrictions (MVFR to IFR) likely this weekend in rain.
Conditions may lift slightly Saturday night between warm and cold
frontal passages.

&&

.MARINE...

Marginal SCA conditions possible this afternoon and evening, but
confidence too low to issue an SCA. Otherwise, light winds 10 kt
or less through Fri night.

Light (at or below 10 kt) south winds Saturday as a warm front
passes north of the waters. Mixing improves considerably Sunday
behind a cold front. Small Craft Advisory conditions likely on
Sunday.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Winter Storm Warning until 7 PM EST this evening for DCZ001.
MD...Winter Storm Warning until 7 PM EST this evening for MDZ013-
     503>506.
     Winter Storm Warning until 1 AM EST Thursday for MDZ003-004-
     501-502.
     Winter Storm Warning until 7 PM EST this evening for MDZ005-
     006-011-014-507-508.
     Winter Weather Advisory until 4 PM EST this afternoon for
     MDZ016>018.
VA...Winter Storm Warning until 10 PM EST this evening for VAZ025-
     026-036>038-503-504-507-508.
     Winter Storm Warning until 7 PM EST this evening for VAZ039-
     050>054-502-506.
     Winter Storm Warning until 1 AM EST Thursday for VAZ027>031-
     040-501-505.
     Winter Weather Advisory until 4 PM EST this afternoon for
     VAZ055>057.
WV...Winter Storm Warning until 10 PM EST this evening for WVZ505-
     506.
     Winter Storm Warning until 1 AM EST Thursday for WVZ050>053-
     055-501>504.
MARINE...Small Craft Advisory from noon today to 6 PM EST this evening
     for ANZ531>533-539>542.
     Small Craft Advisory from 10 AM this morning to 10 PM EST this
     evening for ANZ534-537-543.

&&

$$
SYNOPSIS...LFR
NEAR TERM...LFR
SHORT TERM...LFR
LONG TERM...HTS
AVIATION...LFR/HTS
MARINE...LFR/HTS