Area Forecast Discussion
Issued by NWS Blacksburg, VA

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FXUS61 KRNK 260429
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
1129 PM EST Sat Feb 25 2017

.SYNOPSIS...
High pressure will build in from the west overnight into Sunday
before passing off the southeast coast on Monday. A warm front
will lift northeast toward the region early next week resulting
in an increasing chance of showers by Tuesday into Wednesday.
&&

.NEAR TERM /THROUGH SUNDAY/...
As of 815 PM EST Saturday...

Surface cold front has now pushed well east of the region with
steady cold advection ongoing under gusty west/northwest winds
that will persist overnight. However latest evening RNK sounding
shows the inversion level quite a bit higher than earlier model
forecasts with the much stronger winds above 6K feet. This
despite deepening cold advection should keep most advisory level
winds confined to the highest ridges even as the inversion
lowers some late when the jet aloft is expected to weaken.
Otherwise much drier air within a well mixed environment will
keep things mostly clear overnight, with the northwest slopes
possibly seeing some upslope aided low clouds as the cold pool
aloft rotates through later. However snow showers of any
consequence appear quite iffy given shallow moisture under even
better drying late per progged dewpoints. Thus cut back on snow
shower chances northwest given little precip off any short term
guidance, while leaving in a token dusting of snow over the
higher elevations of northwest Greenbrier where perhaps could
see a band or two overnight. Lows to be much colder than seen in
quite some time with most western locations falling into the
20s, while expecting 30-35 out east where may see periods of
decoupling late.


Previous discussion as of 320 PM EST Saturday...

The cold front/line of convection will move east of the piedmont and
away from the forecast area by 4PM, therefore we will cancel the
severe thunderstorm watch #39. As the cold front tracks to the coast
this evening, modest pressure rises and a 45kt cross barrier jet
will bring breezy conditions to the region. Winds will begin to
subside over the piedmont after midnight but remain breezy across
the mountains, especially along the Blue Ridge where subsidence will
be the greatest. Gusts up to 45 mph are possible this evening. High
pressure builds in by noon Sunday allowing the winds to subside.

An upper level trough will pivot over the Ohio Valley to the Mid
Atlantic region overnight. A short wave axis and lingering low level
moisture may produce light snow across Western Greenbrier this
evening. Flow becomes zonal after midnight and trajectories are lost
from the Great Lakes to end snow showers shortly after midnight. Dry
high pressure will keep the area dry with clear skies Sunday.

Lows tonight will drop into the low to mid 20s across the mountains
and lower 30s east of the Blue Ridge. Believe it or not, these
temperatures are normal for this time of year. Couple the cold
temperatures and wind, Sunday morning temperatures will feel like
they are in the teens across the mountains and low 20s in the east.
Once the wind relaxes, abundant sunshine will help warm temperatures
into the mid 40s west to mid 50s east.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
As of 230 PM EST Saturday...

High pressure heads off the coast Sunday night. A warm front lifts
north across us Monday into Tuesday bringing a threat of rain,
albeit low chance as main low and energy stay over the midwest.
Temperatures warm back to above seasonal levels Tuesday as we get
into the warm sector.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 130 PM EST Saturday...

Not much change from previous forecast. Will see upper trough move
east to the Mid-Atlantic by Thursday. A strong cold front moves
across the region Wednesday night into Thursday. Temperature slide
back to normal or below normal as we dry out Friday into Saturday.

&&

.AVIATION /04Z SUNDAY THROUGH THURSDAY/...
As of 1115 PM EST Saturday...

Upper cold pool will cross parts of the region overnight as
surface high pressure gradually builds east into the area later
tonight through Sunday. Upslope aided low clouds under the
passing shortwave energy aloft likely to result in periods of
VFR/MVFR cigs at KLWB/KBLF overnight, with some of these cigs
possibly spilling out to KBCB and KROA during the early morning
hours of Sunday. However quite uncertain to the eastward/southern
extent of the cloud cover and any snow showers given ongoing
mixing and dry air. For now will include mainly VFR cigs far
western locations, and TEMPO in some ocnl MVFR canopy espcly
around KBLF through daybreak Sunday. This while also leaving
out any snow shower mention attm.

Strong subsidence along with deepening cold advection should
also keep winds gusty across the mountains overnight into
Sunday morning, while speeds subside east of the ridges later
tonight.

Otherwise high pressure to build in overnight and Sunday before
sliding offshore by Monday. This looks to keep VFR under
overall light winds in place from Sunday into early next week
with perhaps some increase in mid/high clouds by Monday.

Extended Aviation Discussion...

A warm front is expected to lift northeast toward the region
Monday night into Tuesday before passing to the north on
Wednesday. This will keep a threat of showers in place
including periods of sub-VFR Tuesday into Wednesday. A cold
front pushes east into the area late Wednesday into Wednesday
night with potential for more widespread MVFR/IFR in showers
until the boundary exits the area early Thursday. Strong
northwest winds along with mountain sub-VFR in upslope low
clouds and light precip will likely follow the front for much of
Thursday. Expect downslope drying to return VFR to eastern
locations by Thursday afternoon.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.

&&

$$
SYNOPSIS...JH/RCS
NEAR TERM...JH/RCS
SHORT TERM...WP
LONG TERM...WP
AVIATION...JH/RCS


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