Area Forecast Discussion
Issued by NWS Blacksburg, VA

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FXUS61 KRNK 191110

Area Forecast Discussion
National Weather Service Blacksburg VA
610 AM EST Fri Jan 19 2018

High pressure over the Lower Mississippi Valley will move east
across the Gulf Coast states today and tonight. Low pressure will
develop in the Central Plains on Sunday then track into the Great
Lakes by Tuesday. This system will push a cold front through the
area on Monday night and Tuesday.


As of 330 AM EST Friday...

Clear sky and dry air mass expected over southwest Virginia,
southeast West Virginia and northwest North Carolina today and
tonight. Surface high pressure will pass to the south of the region
tonight. A 30 to 40 knot west low level jet will result in gusty
winds today. Enough mixing tonight to prohibit excessive temperature
drop. Stayed a little warmer than guidance for lows tonight on the
higher ridges. Went slightly below guidance over the snow cover in
the south.


As of 340 AM EST Friday...

The upper pattern will feature an eastern ridge/western trof through
the weekend, establishing a trend to breezy conditions and temperatures
well above normal. Saturday looks like a fair weather day, but by
Saturday night moisture and isentropic lift associated with a warm
front extending from a low developing over the Rockies will bring a
chance of showers to locations west of the Blue Ridge. Some wet
snowflakes may mix in at the higher elevations before the chance for
showers gradually decreases from south to north on Sunday as the warm
front pushes through. The first part of Monday looks to be mostly dry
but the chance for showers will be increasing in the mountains later in
the day as a strong cold front approaches from the west.

The cold front has a good deal of dynamic support, being driven by low
pressure moving through the Great Lakes and a vigorous closed low
moving through the Ohio valley. The front is expected to be accompanied
by widespread rainfall though lapse rates are not impressive and
surface based instability is largely absent so chances for thunder look
quite low. However, the low level wind field amplifies considerably and
there is a good amount of shear with the front so this could become a
QLCS scenario where embedded convective elements can mix down strong
wind gusts without thunderstorms. QPF does not appear excessive but
downpours may cause local hydro issues. Will be watching this situation
closely to see how it evolves in later model runs.


As of 130 PM EST Thursday...

Temperatures will decrease behind the front on Tuesday, though readings
will still remain above normal for this time of year heading through
the middle part of the week.

Our next chance for precipitation will be a small one Wednesday night
into Thursday as a weak disturbance passes through FL/GA/SC. Otherwise,
dry weather is expected as another area of high pressure builds into
the region.


As of 605 AM EST Thursday...

VFR to prevail under a clear sky through the TAF forecast period.
Models and NAM/RAP Bufkit soundings showed a 30 to 40 knot low
level jet today and tonight. These stronger winds above the
surface inversion may result in low level wind shear in spots
for a few hours until mixing begins this morning and again after
sunset when surface winds diminish. Wind gusts this afternoon
will be from 20 to 30 knots, especially at higher elevations.

Extended Discussion...

High pressure will cover the region Saturday through Sunday.
VFR conditions are expected as well as warming temperatures.
Moisture will return to the west Sunday night into Monday night
with sub- VFR conditions possible in low clouds and rain
showers ahead of another cold front. VFR conditions return
during Tuesday as weak high pressure follows the front in from
the west.


As of 245 PM EST Thursday...

NOAA Weather Radio, WXL60 (Roanoke Transmitter) which broadcasts at
162.475 MHz remains off the air. The phone company continues to
investigate and no estimated time has been given for restoring
this. We apologize for the outage.


NC...Winter Weather Advisory until noon EST today for NCZ001>006-


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