Wind Chill Watch 1, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
328 AM EST Wed Jan 3 2018

.SYNOPSIS...
Low pressure will track northeast from Florida today and be offshore
from the Carolinas tonight. This strong NorEaster will affect the
New England states on Thursday. Meanwhile, another strong and cold
high pressure system moves out of central Canada on Thursday keeping
our region well below normal in temperatures into the weekend.
A cold front arriving in our region from the northwest early next
week will bring precipitation back to our area.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 300 AM EST: Today's snow forecast for our piedmont locations
remains highly uncertain as concern exists over the southern tier
U.S. wave sharpening up and acquiring a negative tilt more quickly
than depicted by the operational models. Currently, water vapor
imagery shows the amplified system already attempting to acquire a
neutral tilt as it moves into western Mississippi. Additional height
falls are indicated upstream over the plains and the fear is that an
injection of cold and dry air into the back of the trough axis will
deepen the feature more sharply and farther west than indicated by
the models. This would result in snowfall being produced farther
inland than featured in the operational models, possible across a
good chunk of our forecat area. At any rate, we're getting set up
for a cold day, with temps largely in the teens in most areas early
this morning, but with little opportunity for insolation today as
the mid and high clouds are already thickening up from the southwest.

Concern is growing that a baroclinic leaf structure might start
lining up farther west than anticipated today as the system goes
solidly neutral tilt over Georgia this afternoon, then negatively
tilted crossing the western Carolinas. Upper jet divergence ahead of
this feature should sharpen up very quickly over the central
piedmont of the Carolinas from 18Z to 21Z and a robust region of
deep layer Q-vector convergence will likely cross the area as well.
Meanwhile, the associated surface reflection will likely develop
near the north Florida coast and then deepen northward over the
Carolina coastal waters. All of these features may well come
together to provide just enough moisture, and improving forcing, for
snow showers to develop mainly southeast of Charlotte. This could
lead to some quick accumulations of snow on the very cold ground,
especially over Union County NC this afternoon and early this
evening. The current feeling is that any strong frontogenesis bands
will set up east of the forecast area, so we shouldn't be looking at
any heavy convective rates in our forecast area - unless the
aforementioned slower and more westward trends accelerate. Radar
trends will need to be monitored closely today for a short fuse SPS
or winter weather advisory should any snow showers threaten the
lower piedmont.

A reinforcing cold front will arrive from the northwest tonight. The
rapidly tightening pressure gradient in the cold advection flow will
require another round of mountin Wind Chill Advisories, with a Wind
Chill Warning needed across the northern mountains where values
colder than minus 20 look likely at times. Also, advisory level
gusts in the cold advection should develop overnight and this will
be wrapped into the wind chill hazard product. Finally, upslope
moisture will wring out snow showers along the TN border in the pre-
dawn hours, continuing beyond the near-term period.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 300 AM EST Wednesday:  The short range fcst period kicks off
on Thursday morning amidst a round of nwfs as moisture banks against
the western slopes of the southern Apps behind a passing front and
beneath a region of channeled vorticity associated with the passage
of the upper trof axis.  Guidance is a bit unclear regarding the
temporal range of this light nwfs event, however given the abundance
of cold air and at least modest moisture in the Nam, opted to keep
slight/chance level pops along the TN line through the day Thursday
and much of Thursday night.  Thus, with snowfall being the
predominant ptype, am expecting some minor sub advisory accums for
these TN line zones, with perhaps slightly higher amounts along the
highest ridgetops and peaks.

Otherwise on Thursday night into Friday morning, cold/broad high
pressure building in from the west will yield enhanced pgfs and thus
flow across the high terrain, thereby presenting another morning of
bitterly cold (at least advisory level) wind chills. This is
especially true across the northern mtns where wind chills could
fall to minus 20 or less, therefore a Wind Chill watch will be
issued for these zones.  Other than that, Friday looks to be a
rather quiet day regionwide aside for the continued cold wave
yielding temperatures 15-20 degrees below normal levels.  Although
flow does look to relax a bit on Friday night, the prolonged cold
could present another night of high terrain wind chill issues.  In
summary, except for the early period mtn nwfs, dry/cold mostly sunny
days and clear cold nights with temperatures remaining generally 15-
20 degrees below normal will highlight the period.  Lastly, would
like to note that because of the reinforcing cold front, low
dewpoints will once again present the possibility of dangerous RH
levels in the upper teens to lower 20s both Thursday and Friday
afternoons.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 135 AM EST Wednesday: The extended forecast period begins
Saturday morning as an upper trough lifts northeast from the Eastern
Seaboard with cold surface high pressure centered near Chicago.  As
this surface high slides SE to the Carolina coast on Sunday, height
values will increase over our area with the 500mb pattern becoming
nearly zonal west to east across the nation. On Saturday evening, a
shortwave crosses the Rockies then reaching the Mississippi Valley
Sunday evening as moisture flux increases out of the Gulf ahead of
the system.  Both the GFS and ECMWF have light wintry precip
beginning in the mountains in the predawn hours on Monday. As the
system approaches from the west on Monday, temperatures warm well
above freezing while precip coverage increases as well. The axis of
the trough reaches the I-75 corridor (Knoxville to ATL) Monday
evening with the bulk of the precip crossing our area. The EC
solution is more dynamic than the GFS as the EC generates another
NorEaster over the mid Atlantic early Tuesday and hits New England
Tuesday night. Both models have our area drying out Tuesday except
NW Flow Snow lingering along the TN border perhaps into Tuesday
night. The current EC has NW Flow Snow ending by 00Z Wednesday,
while GFS has NW Flow gradually diminishing Tuesday night. With the
warming Monday morning, all precip should be in the form of rain by
lunch. A change back to snow in the NC Mtns Monday evening as the
axis moves east of area and colder air filters in from Tennessee.

After temperatures on Saturday are to be at least 15 degrees below
normal, temperatures warm to just below normal for Maxes on Tuesday.
Min Temps slightly above normal Monday night due to the cloud cover.

&&

.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
At KCLT and elsewhere: Mid and high-level moisture are increasing
atop the region ahead of a vigorous southern stream wave that will
yield slowly lowering VFR conditions today. The main concern is that
coastal moisture could wrap westward as the upper support arrives
and produce some snow showers in the vicinity of KCLT late in the
day. Chances for NC piedmont snow have been steadily increasing in
the models and the neutrally-tilted wave moving over the lower MS
River Valley suggests that it will be prudent to carry a PROB30 for
snow showers at KCLT late today, but with VFR conditions in light
snow. Otherwise, expect dry conditions and light winds across the
region, with winds varying from NE to S, but remainly NW at KAVL.
Winds will pick up at KAVL late in the period with the reinforcing
front passing through. Any snow showers should remain NW of KAVL
until just after the current TAF period as better NW flow moisture
gradually gets established.

Outlook: After the coastal system lifts northward through tonight,
and the reinforcing front crosses from the northwest, dry and cold
conditions should get reinforced into the weekend. Moisture and
warmer temperatures will likely return early next week.

Confidence Table...

            08-14Z        14-20Z        20-02Z        02-06Z
KCLT       High 100%     High 100%     High 100%     High 100%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High 100%     High 100%     High 100%     High 100%
KHKY       High 100%     High 100%     High 100%     High 100%
KGMU       High 100%     High 100%     High 100%     High 100%
KAND       High 100%     High 100%     High 100%     High 100%

The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link:

www.weather.gov/gsp/aviation

&&

.FIRE WEATHER...
Very dry air remains in place across the western Carolinas and
northeast Georgia today. With the lack of recent precipitation, 10-
hr fuel moisture levels will likely be in the 8 to 10 percent range,
perhaps just above Fire Danger Statement territory for northeast GA.
Nevertheless, anticipate plenty of lower 20s RH values this
afternoon to further dry fuels. Coordination with the land managers
could be needed on any special products, especially Fire Danger for
northeast GA.

&&

.CLIMATE...
RECORDS FOR 01-03
               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      73 2004     15 1928     55 2000      2 1887
                                                    1879
   KCLT      74 2004     23 1887     55 1907      8 1887
   KGSP      76 1916     28 1979     53 2004      9 1900
                                        2000
RECORDS FOR 01-04
               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      71 2005     16 1919     57 1950     -1 1879
   KCLT      75 1950     27 1904     59 2004      8 1887
                            1887
   KGSP      80 1910     30 1919     58 2004     11 1900
                            1904
RECORDS FOR 01-05
               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      71 1955     17 1959     58 1950     -1 1924
                1950
   KCLT      72 1998     26 1887     59 2007     10 1920
                1950
   KGSP      72 2009     24 1919     57 2007      8 1981
                1955
                1950
RECORDS FOR 01-06
               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      69 1907     20 1879     54 1998     -5 1924
   KCLT      73 1950     23 1884     61 1998      5 1924
                                                    1884
   KGSP      71 1955     26 1924     59 2009      5 1924

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...Wind Chill Advisory from 9 PM this evening to 10 AM EST
     Thursday for GAZ010.
NC...Wind Chill Advisory from 10 PM this evening to noon EST
     Thursday for NCZ048-051>053-058-059-062>065-501-503-505-
     507-509.
     Wind Chill Warning from 10 PM this evening to noon EST
     Thursday for NCZ033-049-050.
     Wind Chill Watch from Thursday evening through Friday morning
     for NCZ033-049-050.
SC...None.

&&

SYNOPSIS...DEO
NEAR TERM...HG
SHORT TERM...CDG
LONG TERM...DEO
AVIATION...HG
FIRE WEATHER...HG
CLIMATE...HG

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
320 PM EST Tue Jan 2 2018

GAZ017-018-026-028-029-NCZ035>037-056-057-068>072-082-502-504-506-
508-510-SCZ001-002-004>014-019-032030-
Habersham-Stephens-Franklin-Hart-Elbert-Alexander-Iredell-Davie-
Catawba-Rowan-Cleveland-Lincoln-Gaston-Mecklenburg-Cabarrus-Union-
Greater Caldwell-Greater Burke-Eastern McDowell-Greater Rutherford-
Eastern Polk-Oconee Mountains-Pickens Mountains-Greater Oconee-
Greater Pickens-Greater Greenville-Spartanburg-Cherokee-York-
Anderson-Abbeville-Laurens-Chester-Greenwood-
320 PM EST Tue Jan 2 2018

This Hazardous Weather Outlook is for the Foothills and Piedmont of
northeast Georgia, western North Carolina, and upstate South
Carolina.

.DAY ONE...Tonight.

A cold arctic airmass has settled in across the region, yielding a
cold wave pattern that will linger throughout the week. Please see
the latest Special Weather Statement for advice on dealing with the
cold.

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

..Wednesday...Cold wave likely. Dry air may also increase fire
danger.
..Thursday...Cold wave likely. Dry air may also increase fire
danger.
..Friday...Cold wave likely.
..Saturday...Cold wave likely.
..Sunday...No hazardous weather is expected at this time.
..Monday...No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

GAZ010-NCZ033-048>053-058-059-062>065-501-503-505-507-509-SCZ003-
032030-
Rabun-Avery-Madison-Yancey-Mitchell-Swain-Haywood-Buncombe-Graham-
Northern Jackson-Macon-Southern Jackson-Transylvania-Henderson-
Caldwell Mountains-Burke Mountains-McDowell Mountains-
Rutherford Mountains-Polk Mountains-Greenville Mountains-
320 PM EST Tue Jan 2 2018

This Hazardous Weather Outlook is for the mountains of northeast
Georgia, western North Carolina and upstate South Carolina.

.DAY ONE...Tonight.

A cold arctic airmass has settled in across the region, yielding a
cold wave pattern that will linger throughout the week. Please see
the latest Special Weather Statement for advice on dealing with the
cold.

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

..Wednesday...Cold wave likely. Dry air may also increase fire
danger.
..Thursday...Cold wave likely. Dangerously cold wind chills are
possible during the early morning hours.
..Friday...Cold wave likely. Dangerously cold wind chills are
possible during the early morning hours.
..Saturday...Cold wave likely.
..Sunday...No hazardous weather is expected at this time.
..Monday...No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

Wimberley

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
331 AM EST Wed Jan 3 2018

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-040900-
Rabun-Habersham-Stephens-Franklin-Hart-Elbert-Avery-Alexander-
Iredell-Davie-Madison-Yancey-Mitchell-Swain-Haywood-Buncombe-
Catawba-Rowan-Graham-Northern Jackson-Macon-Southern Jackson-
Transylvania-Henderson-Cleveland-Lincoln-Gaston-Mecklenburg-
Cabarrus-Union-Caldwell Mountains-Greater Caldwell-
Burke Mountains-Greater Burke-McDowell Mountains-Eastern McDowell-
Rutherford Mountains-Greater Rutherford-Polk Mountains-
Eastern Polk-Oconee Mountains-Pickens Mountains-
Greenville Mountains-Greater Oconee-Greater Pickens-
Greater Greenville-Spartanburg-Cherokee-York-Anderson-Abbeville-
Laurens-Chester-Greenwood-
Including the cities of Clayton, Pine Mountain, Mountain City,
Cornelia, Baldwin, Demorest, Clarkesville, Hollywood, Boydville,
Toccoa, Royston, Whitworth, Lavonia, Franklin Springs, Canon,
Hartwell, Nuberg, Reed Creek, Elberton, Fortsonia, Middleton,
Ruckersville, Ingalls, Banner Elk, Newland, Bethlehem, Ellendale,
Millersville, Taylorsville, Hiddenite, Stony Point, Statesville,
Mooresville, Farmington, Fork Church, Mocksville, Advance, Faust,
Mars Hill, Marshall, Walnut, Allenstand, Hot Springs, Luck,
Swiss, Burnsville, Celo, Micaville, Ramseytown, Busick,
Mount Mitchell State Park, Spruce Pine, Poplar, Newfound Gap,
Alarka, Almond, Bryson City, Luada, Smokemont, Wesser,
Waynesville, Waterville, Canton, Cruso, Cove Creek,
Lake Junaluska, Asheville, Hickory, Newton, St. Stephens,
Salisbury, Robbinsville, Stecoah, Cullowhee, Tuckasegee, Sylva,
Franklin, Rainbow Springs, Kyle, Nantahala Lake, Highlands,
Wolf Mountain, Cashiers, Brevard, Cedar Mountain, Little River,
Hendersonville, Fletcher, Dana, East Flat Rock, Tuxedo, Etowah,
Shelby, Kings Mountain, Lincolnton, Crouse, Gastonia, Charlotte,
Huntersville, Matthews, Concord, Kannapolis, Monroe, Trinity,
Indian Trail, Weddington, Patterson, Kings Creek, Lenoir,
Sawmills, Granite Falls, Jonas Ridge, Morganton, Pleasant Grove,
Valdese, Ashford, Sugar Hill, Woodlawn, Old Fort, Marion, Nebo,
Dysartsville, Fero, Glenwood, Lake Lure, Forest City,
Rutherfordton, Spindale, Saluda, Tryon, Columbus, Lake Adger,
Mill Spring, Mountain Rest, Walhalla, Westminster, Pumpkintown,
Tigerville, Gowensville, Caesars Head, Cleveland, Marietta,
Seneca, Oakway, Easley, Dacusville, Clemson, Greenville, Taylors,
Greer, Mauldin, Fork Shoals, Simpsonville, Berea, Spartanburg,
Gaffney, Catawba, Rock Hill, Anderson, Abbeville, Calhoun Falls,
Laurens, Clinton, Union, Monarch Mills, Blackstock, Chester,
Cornwell, Great Falls, Ware Shoals, and Ninety Six
331 AM EST Wed Jan 3 2018

...AN ARCTIC COLD WAVE WILL CONTINUE ACROSS THE REGION THROUGH AT
LEAST SATURDAY...

A very cold arctic airmass has built over the region and will
persist through the week. Expect temperatures to fall into the
single digits to teens across the mountains at times each night,
with lows in the teens to 20s across the foothills and piedmont
this week. Daytime maximum temperatures will struggle to get above
the freezing mark most days this week, especially across the
mountains where highs in the 20s will be common.

The cold weather will likely result in high demand for
electricity across the region. Power outages may result from the
heavy electrical load. Those who require electricity for heating
or medical equipment should consider having backup heat or
electrical sources available.

Take steps now to protect your property and health from the
extreme cold. If you go outside, wear several layers of loose
fitting, lightweight, warm clothing rather than one layer of heavy
clothing. Mittens are warmer than gloves. Wear a hat and cover
your mouth with a scarf. It is imperative that parents make sure
children returning to school this week are prepared for the
prolonged cold, especially if they will be outside waiting at bus
stops in the mornings. If driving, keep your gas tank near full to
avoid ice in the tank and fuel lines. Check your antifreeze and
windshield washer fluid levels. Be sure to carry a fully charged
cell phone.

While at home, consider allowing indoor plumbing fixtures to drip
to permit water to trickle through pipes and inhibit freezing.
Use caution with space heaters in order to avoid fire or injury.
If emergency generators will be used, they must be situated
outdoors in well-ventilated areas to prevent carbon monoxide
poisoning. Also, remember to check in on family, friends, and
elderly neighbors who might be susceptible to the cold. Do not
forget about your pets and livestock. Make sure they have a source
of water that will not freeze and a warm place to take shelter
from the wind and cold.

Do not attempt to walk on frozen ponds, lakes, or streams, as the
ice will not be thick enough to support the weight - even of a
child.

A cold wave is defined as average daily temperatures 12 degrees or
more below normal mid-January average daily temperatures for 48
hours or longer. Normal mid-January average daily temperatures
are, for Asheville 37, Charlotte 41, and GSP 42. By definition it
follows that a cold wave is when the average daily temperature for
Asheville is 25, Charlotte is 29, and GSP is 30.

CDG