Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 111921

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
321 PM EDT Sun Mar 11 2018

.SYNOPSIS...Low pressure will pass well south of the area late
tonight and redevlop off of the Carolinas Monday and then
intensify rapidly as it tracks northeastward into the Canadian
Maritimes by Tuesday night. Weak high pressure will build over
the area for the end of the week.


.NEAR TERM /THROUGH MONDAY/...Upper level shortwave- trough
currently over Missouri will move ewd across the mid MS valley
this evening and across the central/southern Appalachians on
Monday. Forcing associated with this wave will result in light
to moderate precip overspreading our southwest counties late
this evening or overnight. 12Z deterministic models have
remained pretty consistent with prior runs with regards to the
track of the sfc low passing to the south and the coastal low
developing off the Carolinas but appears to have slowed down
precip onset time and amounts across our southwest counties.
Precip shield moves into areas of northwest VA, eastern
panhandle of WV and northern MD after 12Z with areas to the east
remaining mainly dry as primary low weakens. Coastal low then
begins to organize and strengthen Mon, but will likely remain
too far offshore to give our area any sig precip other than a
glanzing blow to southern MD. Snow should be primary p-type Mon
morning with p-type during the afternoon depending more heavily
on precip rates given marginal bdry layer temps.



Some lingering precip Mon evening along the western shore of the
Chesapeake Bay, then turning colder and breezy as low pres
strengthens rapidly offshore. Upslope snow showers will continue
through mid week in cold cyclonic flow.



Upper level shortwave will be over our area on Wednesday
allowing for passing snow showers over our area, but mainly west
of the Blue Ridge. Temperatures will be below normal, with
highs reaching the the low 40s and lower values at higher
elevations. Another shortwave affect us on Thursday as warm air
is advected and with increasing heights. At the surface, a high
pressure system builds in with some showers possible but
expecting drier conditions than Wednesday. High pressure will
remain in control into Friday with return flow settling in and
high temperatures reaching the 50s, maybe some 60s.
Precipitation chances increase on Saturday with a front
approaching. It will then stall near our area into Sunday.



Thickening clouds tonight with IFR conditions developing at KCHO
after 12Z through about 18Z. Mainly MVFR cigs elsewhere with -SN
at times. Winds strengthening Mon night and Tue and becoming NW.

An upper level disturbance could bring sub-VFR conditions
Wednesday with possible passing showers over our area.
Conditions should become drier on Thursday into Friday with VFR
conditions expected as high pressure builds in.



Winds will begin to strengthen late tonight into Tuesday with
SCA conditions likely for parts of the waters late tonight and
everywhere Mon through the end of the week. A period of gale
force winds is likely Tue.

Wind gusts will be near or above the small craft advisory
criteria Wednesday into Thursday. Therefore, expecting
advisories for most of this period. Winds should decrease into
Friday below criteria but still breezy.


VA...Winter Storm Warning from 8 PM this evening to 2 PM EDT Monday
     for VAZ025-036-503-504-508.
     Winter Weather Advisory from midnight tonight to noon EDT
     Monday for VAZ026-027-029-037>039-507.
WV...Winter Weather Advisory from midnight tonight to noon EDT
     Monday for WVZ055-501-502-505-506.
MARINE...Small Craft Advisory from 6 AM Monday to 6 AM EDT Tuesday for
     Small Craft Advisory from 2 AM Monday to 6 AM EDT Tuesday for


MARINE...IMR/LFR is the U.S. government's official web portal to all federal, state and local government web resources and services.