Wind Chill Watch 1, NWS Blacksburg, VA

Alleghany County, NC, Ashe County, NC, Watauga County, NC, Alleghany County, VA, Bath County, VA, Bland County, VA, Botetourt County, VA, Carroll County, VA, City of Buena Vista, VA, City of Covington, VA, City of Galax, VA, City of Lexington, VA, City of Radford, VA, City of Roanoke, VA, City of Salem, VA, Craig County, VA, Floyd County, VA, Giles County, VA, Grayson County, VA, Montgomery County, VA, Pulaski County, VA, Roanoke County, VA, Rockbridge County, VA, Smyth County, VA, Tazewell County, VA, Wythe County, VA, Greenbrier County, WV, Mercer County, WV, Monroe County, WV, Summers County, WV

Area Forecast Discussion
National Weather Service Blacksburg VA
1137 PM EST Tue Jan 2 2018

.SYNOPSIS...
A large area of cold high pressure covering the region will
slide east as a reinforcing surge of Arctic air arrives Thursday
and lingers into the weekend. A coastal storm will move
northeast along the Atlantic Coast Wednesday night through
Friday, helping to keep cold and windy conditions in our area.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
As of 700 PM EST Tuesday...

Made a few minor adjustments to existing set of grids to reflect
rapidly falling temperatures this evening due to clear skies,
calm winds, and dry airmass - setting the stage for a good
radiative event. May see some readings approach or even fall a
few degrees below zero in some of the deeper mountain valleys,
with some readings below 10 degrees in some lower sheltered
areas of the Piedmont before arrival of high level clouds
arrests further fall within a few hours of daybreak. Otherwise,
no changes needed to forecast at the present time.

As of 230 PM EST Tuesday...
The 17Z (Noon EST) sfc map showed a sprawling area of high
pressure extending from the central plains to the Mid-Atlantic
region keeping dry and cold conditions in place. A shortwave
trof digging into the southern plains rapidly moves into the
gulf coast by Wednesday morning with a fast moving northern
stream shortwave pushing south south of the northern plains into
the Mississippi Valley by Wednesday morning.

The approaching southern stream system will allow mid and high level
clouds to enter our area from the south after 06Z (1 AM EST). Until
that time, temps should rapidly fall this evening, then level out
late. Still leaned toward the coldest guidance considering guidance
has shown a warm bias recently.

On Wednesday our attention turns the development of a low pressure
system of the southeast U.S. coast. All deterministic models keep
our forecast area dry through Wednesday, with a small number of high
res ensembles members generating some very light precip into the far
southeast portion of our forecast area before 00Z Thursday (7 PM
Wednesday EST). Considering the dry air mass in place and the a
fairly good consensus in the deterministic models, kept the forecast
dry through Wednesday. With warming 850mb temps, readings should be
warmer compared to today, but perhaps not as mild as guidance
indicates considering a widespread canopy of mid/high level clouds.
Therefore, undercut guidance by a couple of degrees for highs.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 240 PM EDT Tuesday...

The main forecast issues in the short-term are the developing
coastal low off the southeast coast and a renewed push of arctic
air behind it. The majority of models and ensembles continue to
keep measurable precipitation from the coastal system east of
our CWA but a few, including the 12z ECMWF continue to fling
small amounts of precip into the far eastern sections late
Wednesday into early Thursday. Have maintained only slight
chance pops and no QPF at this point but will obviously have to
be monitored closely for a substantial westward deviation from
the latest. By midday Thursday the surface low will be off the
VA coast, north of our latitude and accelerating rapidly
northeast toward the Canadian maritimes. Strong northwest winds
and cold advection pattern will resume in the wake this system
with the usual upslope snow showers in the favored areas. Temps
by Friday morning will be comparable to the current air mass
with near zero to low single digits in the mountains to near 10F
in the piedmont.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 455 AM EST Tuesday...

Saturday will be the last very cold day in the current outbreak with
temps again similar to the most recent and a few record lows
possibly threatened. By Sunday the upper flow will become briefly
zonal with rising heights and the beginnings of a warmup. Models
continue to advertise a southern stream system late Monday-Tuesday.
Although p-type remains somewhat uncertain it is more likely than
not that it will be predominantly liquid but a period and/or areas
of mixed phase is also a strong possibility. Colder air will wrap in
behind this system although it does not appear be anything
comparable to the current regime, especially if the EC is to be
believed.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
As of 1135 PM EST Tuesday...

VFR conditions will persist at all Blacksburg terminal forecast
sites (KROA, KLYH, KDAN, KBCB, KBLF, KLWB) through the upcoming
terminal forecast period that ends at 06Z/1AM Thursday.

High level clouds will begin to impinge upon the area after
09Z/4AM (this morning), with a mid-level deck expected by late
morning/early afternoon, further lowering to a deck around 6-7K
feet by mid-late afternoon as intensifying low pressure system
moves northeast along the East Coast. This system is still
expected to remain far enough to our east to ensure VFR weather
persists in the Blacksburg terminal forecast airspace, but
flight conditions will be markedly worse closer to the coast.
Confidence remains high for forecasted ceiling, visibility, and
winds for the next 24 hours.

Extended Discussion...
Passage of the intensifying low pressure system, and approach
of the next Arctic high pressure system will cause winds to
shift into the northwest and increase markedly after 06Z/1AM
Thursday. A prolonged period of strong northwesterly winds with
MVFR to localized IFR flight restrictions due to upsloping
clouds and snow showers will begin west of the Blue Ridge late
Wednesday night, then continue into Saturday. East of the Blue
Ridge, gusty downsloping winds will maintain VFR flight
conditions across the Piedmont.

Arrival of the surface high pressure system on/by Sunday will
bring diminishing winds, a return to widespread VFR weather
(even in the mountains), and slowly moderating temperatures.

&&

.FIRE WEATHER...
Antecedent conditions are dry. In spite of the cold, the
dryness of the current Arctic airmass and lack of meaningful
precipitation the last 30-60 days is beginning to set the stage
for potential fire concerns. Sun angle is low so the active burn
window is small, however with little or no moisture recovery at
night conditions are becoming favorable to sustain fire starts
if they occur. Ignition sources for this time of year given the
cold weather would most likely come from hot ashes being dumped
out by folks using wood stoves.

&&

.CLIMATE...
A continued series of Arctic air masses is expected during the
next 3 or 4 days, likely threatening record low maximum
temperatures and perhaps even record low minimum temperatures.

Here are the records for the next several days.

Climate Records Summary

Wednesday 01/03/2018
Site  MinT Year  LoMax Year
KBLF    -5 1979    11 1979
KDAN    12 1979    30 1970
KLYH     5 1979    20 1979
KROA     4 1979    21 1979
KRNK    -2 1979    20 2012

Thursday 01/04/2018
Site  MinT Year  LoMax Year
KBLF    -1 1981    17 2010
KDAN    12 2001    26 1979
KLYH    10 1981    22 1919
KROA     8 1919    24 1919
KRNK    -2 1979    19 1979

Friday 01/05/2018
Site  MinT Year   LoMax Year
KBLF    -4 1981    14 1999
KDAN     9 1958    25 1981
KLYH     1 1969    21 1959
KROA     5 1969    16 1912
KRNK    -2 1981    12 1981

Saturday 01/06/2018
Site  MinT Year    LoMax Year
KBLF    -4 2014    14 1988
KDAN    10 1999    27 1999
KLYH     3 1924    18 1912
KROA     2 1924    18 1912
KRNK    -2 2014    13 1959

&&

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

&&

SYNOPSIS...PH
NEAR TERM...PH/WERT
SHORT TERM...PC
LONG TERM...PC/RAB
AVIATION...WERT
FIRE WEATHER...PM
CLIMATE...RAB

Hazardous Weather Outlook...UPDATED
National Weather Service Blacksburg VA
244 PM EST Tue Jan 2 2018

NCZ003>006-019-020-VAZ032>035-043>047-058-059-031945-
Surry-Stokes-Rockingham-Caswell-Wilkes-Yadkin-Patrick-Franklin-
Bedford-Amherst-Henry-Pittsylvania-Campbell-Appomattox-Buckingham-
Halifax-Charlotte-
244 PM EST Tue Jan 2 2018

This Hazardous Weather Outlook is for north central North Carolina,
northwest North Carolina, central Virginia, south central Virginia,
southwest Virginia and west central Virginia.

.DAY ONE...This afternoon and tonight.

Hazardous weather is not expected at this time.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

Wind chill readings of 0 to -10 will be possible both Friday and
Saturday mornings. A Wind Chill advisory will likely be needed for
this period.

A light wintry mix of precipitation could occur early Monday
morning.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

NCZ001-002-018-VAZ009>020-022>024-WVZ044-507-031945-
Ashe-Alleghany NC-Watauga-Smyth-Bland-Giles-Wythe-Pulaski-Montgomery-
Grayson-Carroll-Floyd-Craig-Alleghany VA-Bath-Roanoke-Botetourt-
Rockbridge-Monroe-Eastern Greenbrier-
244 PM EST Tue Jan 2 2018

This Hazardous Weather Outlook is for northwest North Carolina,
southwest Virginia, west central Virginia and southeast West
Virginia.

.DAY ONE...This afternoon and tonight.

Hazardous weather is not expected at this time.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

Wind chill readings of -5 to -15 will be possible Thursday through
Saturday mornings. A Wind Chill Advisory will likely be needed for
this period.

Strong northwest winds behind a passing Arctic cold front could gust
to 50 mph Thursday into Friday morning. A Wind Advisory will likely
also be needed.

In addition...a wintry mix of precipitation will be possible
especially Monday morning.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

VAZ007-WVZ042-043-508-031945-
Tazewell-Mercer-Summers-Western Greenbrier-
244 PM EST Tue Jan 2 2018

This Hazardous Weather Outlook is for southwest Virginia and
southeast West Virginia.

.DAY ONE...This afternoon and tonight.

Hazardous weather is not expected at this time.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

Wind chill readings of -10 to -25 will be possible Thursday through
and Saturday mornings. A Wind Chill Advisory or Wind Chill Warning
will likely be needed.

Strong northwest winds could gust to 45 or 50 mph behind an Arctic
cold front Thursday into Friday morning. A Wind Advisory will likely
also be needed.

In addition...a wintry mix will be possible Monday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.