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Area forecast discussion 
National Weather Service Baltimore Maryland/Washington District of Columbia
1000 PM EST Thursday Jan 29 2015

Synopsis...
a cold front will swing through the region tonight. High pressure
building into the region will bring windy and cold conditions
Friday and Friday night. The high will build over the area
Saturday...but low pressure may impact the area later Sunday into
Monday. Cold high pressure will return for the middle portion of
next week.

&&

Near term /until 6 am Friday morning/...
most of the precipitation has moved out of the County Warning Area...and thus the large
portion of the advisories have been cancelled.

There are a couple of exceptions. Have extended winter weather
advisories for portions of northern Maryland and the eastern West
Virginia Panhandle /east of the Allegheny Front/ until 1 am as a
vorticity maximum will likely bring some additional late evening precipitation
just south of the Mason Dixon line. Expect p-type to eventually
transition to snow...but initially there could be some freezing
rain or freezing drizzle in those areas that are below freezing at
the surface. RUC for example shows a brief period of -zr at hgr/mrb
late this evening. Will have to watch further east toward
Baltimore...but by the time this next round of precipitation would get
there think p-type would be just snow and little accumulation is
expected thus no advisory extension that far east.

Winter weather advisories also continue on the western slopes of
the Potomac Highlands as precipitation will transition to snow and
snow could be heavy at times late tonight into Friday morning.

Synoptically...as was mentioned earlier a vorticity maximum associated with
an upper trough will move through tonight and will be accompanied
by a cold frontal passage. Frontal passage will initiate a wind shift to the
northwest. Northwest winds will begin to become gusty over the
Potomac Highlands late tonight. Re-populated winds using the NAM
and winds remain below Wind Advisory criteria through
tonight...but are expected to reach criteria during the day
Friday /see short term/.

&&

Short term /6 am Friday morning through 6 PM Friday/...
have issued a Wind Advisory for much of the County Warning Area except for the
central Virginia foothills area. BUFKIT point forecast soundings from NAM
and GFS suggest at or above 40 knots able to mix down to the surface
particularly in the afternoon and evening hours. Wbcnpwlwx has
already been issued. Strong vorticity may also produce scattered snow
showers which are reflected in the forecast.

Previous...

High pressure building into the middle Atlantic will lead to a strong pressure gradient
across the area. This in turn will lead to a windy day. BUFKIT
x-sections are showing inxs of 40 knots a few thousand feet off the grnd.
This will have the potential to be brought to the surface. We are advsrtsg the
possiblity of a Wind Advisory - most likely areas will be above 1500 feet and
across the northern 1/2 of the forecast area.

Highs in the lm30s.

&&

Long term /Friday night through Thursday/...
high pressure building over the range Friday night will lead to chilly temperatures. Lows
in the teens across much of the area. Winds will be diminishing
overnight...but west/ cold temperatures winds chills expeceted to be in the single
digits east of the mountains presently seeing values as low as -14 in The
Highlands. If this trend continues a Wind Chill Advisory will be needed
for our far western area.

Sat looks to be M sunny but cold west/ highs ranging from the u20s to
the mu30s over most of the area.

Sat night will be cold...but a little warmer than Friday night. No winds so
wind chill will not be a concern.

What had been a split in the models between a low track to our north
and another track to our south seems to be consolidating around the
southern track now...taking it east through S Virginia or NC. That supports
snow for much if not all of our region. Would be passing through at a
good clip but accumulating snow certainly a possibility for Sun
afternoon into Monday morning.

High pressure will follow for Tuesday. Next cold front poised for
Wednesday.

&&

Aviation /03z Friday through Tuesday/...
can/T rule out brief light snow or freezing drizzle at mrb
tonight...otherwise rest of the terminals look dry with VFR cloud
deck around 5k feet. Cold front moves through after midnight. This
will allow for a wind shift spreading east through the terminals.
Winds will be very gusty during the day on Friday...possibly at or above
40 knots from afternoon into evening. Will also have to watch for
afternoon snow showers and flurries but confidence too low to
mention in taf at this time.

Windy conds Friday and Friday night as high pressure builds into the area. No
probs expeceted aviation-wise Sat or Sat night.

Snow and IFR conditions are possible Sunday afternoon into Monday
morning as low pressure slides by to our south. VFR for Tuesday.

&&

Marine...
Small Craft Advisory conditions continue up the Bay tonight due to S/southeast winds. Wind
shift occurs with a cold frontal passage late tonight...and gales
are expected on Friday lasting into Friday night.

A Gale Warning is in effect from Friday morning through the Erly hours of Sat
morning..and then an Small Craft Advisory will likely go into effect aftrwards for the
remainder of the night. Winds will be diminishing for Sat and Sat night.

Gusty winds and a Small Craft Advisory are possible on Monday into
Monday night as low pressure intensifies offshore.

&&

Tides/coastal flooding...
anomalies have increased to around 1.5 feet on the western shore of
the Chesapeake Bay...closer to 1 feet on the upper tidal Potomac
River. However due to the relatively low astronomical
tides...these anomalies are not expected to result in minor tidal
flooding overnight. In addition...winds shift to the northwest
late tonight into Friday morning and anomalies should begin to
decrease.



&&

Lwx watches/warnings/advisories...
District of Columbia...Wind Advisory from noon Friday to midnight EST Friday night
for dcz001.
Maryland...Wind Advisory from 10 am Friday to midnight EST Friday night
for mdz003-501-502.
Winter Weather Advisory until 1 am EST Friday for mdz003>005-
502.
Wind Advisory from noon Friday to midnight EST Friday night
for mdz004>006-011-013-014-016>018-503>508.
Winter Weather Advisory until noon EST Friday for mdz501.
Virginia...Wind Advisory from 10 am Friday to midnight EST Friday night
for vaz025>031-503-504-507-508.
Wind Advisory from noon Friday to midnight EST Friday night
for vaz040-051>055-057-501-502-505-506.
Winter Weather Advisory until noon EST Friday for vaz503.
WV...Wind Advisory from 10 am Friday to midnight EST Friday night
for wvz050>053-055-501>506.
Winter Weather Advisory until 1 am EST Friday for wvz051>053.
Winter Weather Advisory until noon EST Friday for wvz501-503-
505.
Marine...Small Craft Advisory until 6 am EST Friday for anz530>534-
537>543.
Gale Warning from 6 am Friday to 1 am EST Saturday for
anz530>543.

&&

$$
Synopsis...bpp
near term...bpp
short term...abw
long term...cas
aviation...bpp/cas/abw
marine...bpp/cas/abw
tides/coastal flooding...

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