Winter Weather in Georgia, February 6 to 7, 2021

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
310 PM EST Sat Feb 6 2021

.SYNOPSIS...
Low pressure will spread moisture north across our region through
tonight then move off the East Coast on Sunday. Dry high pressure
builds back into the area on Monday. Unsettled weather is
possible through the rest of the week.

&&

.NEAR TERM /THROUGH SUNDAY/...
As of 230 PM: A well defined shortwave is moving toward Arkansas,
on track to reach the southern Appalachians by around daybreak
Sunday. A relatively weak but dry sfc high is present across the
upper OH Valley and Eastern Seaboard; on the southern fringe of this
high is a stalled front. The shortwave will pull the front northward
as a warm front over the high, with cyclogenesis occurring along
the GA/SC coasts. In-situ CAD is expected to develop as precip
develops, with precip expected throughout the CWA at some point
tonight. The morning passage of the shortwave axis will erode the
CAD, end precip, and lead to scattering clouds east of the mountains
by midday Sunday. A minor NW-flow snow event will occur along
the NC/TN border in the early to mid-morning timeframe. However,
the main story for the period will be the wintry precip developing
within the CAD, mainly overnight.

Dewpoints being what they are in the teens and lower 20s on obs
from across the CWA, there appears a lot of dry air to overcome
before precip can accumulate at all. Thus, seems reasonable to
expect reasonably strong evaporative cooling at the onset of
precip. The midday HRRR runs seemed to have initialized the dry
air better than other models, and indeed the HRRR reflects the
wet-bulbing concurrent with its precip depiction. Still thinking
snow will predominate as p-type where temps are cold enough this
aftn/evening. That said, special 18z sounding from KFFC shows a
stronger warm nose than what any of the models depict, but the NAM
is closest. How far this warm nose works north and west, into the
area where temps are closest to or below freezing, will determine
the extent of the wintry precip. The models in general are closer
than they were yesterday at this time, though the NAM remains most
bullish in terms of WAA over the wedge. Thinking sfc temps however
are more likely to remain just above freezing in the area where
the warm layer is most in play. Thus, the transition zone between
rain and snow remains pretty sharp across the upper Piedmont and
Foothills, with sleet and eventually FZRA replacing snow in the
colder areas later tonight, after the best forcing has shifted
north and east. The loss of better upper level moisture, following
continuing northward motion of the warm front, also suggests FZRA
overtaking sleet/snow at some point, but by that time the remaining
chances will be mostly associated with the developing NW flow,
which would tend to be rime icing if not snow. Overall, thinking the
hazards are good as-is: Winter Storm Warning for the mountains of
GA/SC/NC as well as the northern NC foothills zones, and a Winter
Wx Advisory for the adjacent part of the NW NC Piedmont.

Gusty winds will occur in high elevations overnight and tomorrow
morning, at least, though the 850mb flow is not especially strong
and impacts from these winds are not expected to be enough for
any wind headlines. The aforementioned NW Flow snowfall in the
morning likely won't amount to much particularly in light of
the overnight precip, but a few flurries could continue into
early afternoon. 850mb winds continue to be unimpressive in this
regard, which is another reason not to get that excited about
the NW flow. Temps will rebound into the 50s by afternoon across
the Piedmont, although if the clouds hang on a bit longer than
expected (which wouldn't be that surprising, coming out of CAD),
that may be a little optimistic. The higher mountains will remain
near freezing, but the valleys should warm back into the 40s.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
As of 245 PM EST Saturday: The short-term forecast picks up at 00z
on Monday with heights recovering across the region as very broad
upper trofing lifts NE and flattened upper ridging builds to our
south. Our area will remain under nearly zonal upper flow thru the
short-term period and into the extended as upper ridging remains
centered to our south. At the surface, broad high pressure will be
spreading over our region as another robust Nor'easter moves farther
off the New England coast. The high will be fairly transitory and
will slide eastward and over the Atlantic Coast by late Mon/early
Tues. On Tues, another weak low develops along a moist frontal bndy
just to our west and pushes a weak cold front thru the CWFA Tues
aftn/evening as the period ends. Monday will be dry with solid chance
PoPs over most of the CWFA on Tues with the fropa. Any QPF that does
fall should be minimal (ie, no more than 0.1 inches for most zones).
Most of the precip that does fall should be rain, however temps do
appear to support light snow showers over the mtns and northern NC
Foothills early Tues. Any accums should be 0.1 inches or less.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
As of 220 PM EST Saturday: the extended fcst picks up at 00z on
Wednesday with flattened upper ridging to our south and very broad
upper trofing moving east of the Great Lakes. Over the next couple
of days, the sub-tropical upper ridge is expected to amplify to our
southeast as another upper trof begins to dig down across the Central
CONUS. For the remainder of the period, the long-range models remain
quite different with respect to the large-scale pattern evolution.
The GFS develops a much broader and deeper upper trof from Friday
onward while the ECMWF (and to a lesser extent the CMC), are much
more muted with respect to the trof's amplification. At the sfc,
broad but relatively moist and transitory high pressure will be
spreading over the area from the NW as the period begins late Tues/
early Wednesday. Over the next 24 to 48 hrs, the high will shift
eastward and move over New England setting up a weak wedge/CAD over
the Carolinas. By late Thursday, another low will develop over the
ArkLaTex region and lift NE towards the Ohio River Valley by early
Friday. This will bring widespread precip to the fcst area for
Thursday and at least part of Friday. By the end of the period on
Saturday, robust-looking Canadian high pressure pushes its way
into the region with drier and much cooler air.

&&

.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
At KCLT and elsewhere: Altostratus will thicken this afternoon, not
looking likely to lower into impactful low-VFR range until the first
bands of light precip spread in from SW to NE, starting in the late
afternoon. At KCLT, kept the low VFR in TEMPO until precip is likely
enough to prevail. Low pressure passing near the SE Coast overnight,
along with developing in-situ cold air damming, should result in
cigs crashing to LIFR at all sites by late evening. KAVL and KHKY
will see snow overtake rain as predominant p-type as temps drop
via evaporative cooling. Elsewhere, temps likely will hover just
above freezing, but some wintry mix remains possible at KGSP/KGMU
in the late evening, and KCLT overnight (likely between the end
of evening ops and before morning ops begin). Introduction of a
warm layer into the otherwise cold profiles aloft will mean PL more
likely than SN, when not purely RA. Departure of the low will turn
winds NW and downslope from early morning onward, with the shift
progressing NW to SE. This should erode the CAD, though not likely
until nearly the end of the period...except at KAVL. There, the
wx will turn to more of a NW flow event, allowing snow showers to
linger a bit longer, some hope for MVFR, and winds to become gusty.

Confidence Table...

            20-02Z        02-08Z        08-14Z        14-18Z
KCLT       High 100%     Low   47%     Low   54%     Med   75%
KGSP       High 100%     Med   64%     Med   62%     High  84%
KAVL       High 100%     Med   66%     High  88%     Med   78%
KHKY       High 100%     Med   78%     High  86%     High  82%
KGMU       High 100%     Med   64%     Med   70%     High  86%
KAND       High  84%     Low   36%     Med   66%     High  80%

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

www.weather.gov/gsp/aviation

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...Winter Storm Warning until noon EST Sunday for GAZ010-017.
NC...Winter Storm Warning until noon EST Sunday for NCZ033-048>053-
     058-059-062>065-501>507-509.
     Winter Weather Advisory until noon EST Sunday for NCZ035>037-
     056-068-069-508-510.
SC...Winter Storm Warning until noon EST Sunday for SCZ001>003.

&&

SYNOPSIS...DEO
NEAR TERM...Wimberley
SHORT TERM...JPT
LONG TERM...JPT
AVIATION...Wimberley

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
340 PM EST Sat Feb 6 2021

GAZ010-017-NCZ033-048>053-058-059-062>065-501>507-509-SCZ001>003-
072045-
Rabun-Habersham-Avery-Madison-Yancey-Mitchell-Swain-Haywood-Buncombe-
Graham-Northern Jackson-Macon-Southern Jackson-Transylvania-
Henderson-Caldwell Mountains-Greater Caldwell-Burke Mountains-
Greater Burke-McDowell Mountains-Eastern McDowell-
Rutherford Mountains-Polk Mountains-Oconee Mountains-
Pickens Mountains-Greenville Mountains-
340 PM EST Sat Feb 6 2021

...WINTER STORM WARNING IN EFFECT UNTIL NOON EST SUNDAY...

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

.DAY ONE...This afternoon and tonight.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Winter Storm Warning.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Winter Storm Warning.

.SPOTTER INFORMATION STATEMENT...

Spotters are requested to report snow and ice accumulations to our
office.

NCZ035>037-056-068-069-508-510-072045-
Alexander-Iredell-Davie-Catawba-Cleveland-Lincoln-Greater Rutherford-
Eastern Polk-
340 PM EST Sat Feb 6 2021

...WINTER WEATHER ADVISORY IN EFFECT UNTIL NOON EST SUNDAY...

This Hazardous Weather Outlook is for the northwest Piedmont and
southern foothills of western North Carolina.

.DAY ONE...This afternoon and tonight.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Winter Weather Advisory.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Winter Weather Advisory.

.SPOTTER INFORMATION STATEMENT...

Spotters are requested to report snow and ice accumulations to our
office.

GAZ029-NCZ082-SCZ011>014-019-072045-
Elbert-Union NC-Abbeville-Laurens-Union SC-Chester-Greenwood-
340 PM EST Sat Feb 6 2021

This Hazardous Weather Outlook is for locations southeast of I-85 in
northeast Georgia, Piedmont North Carolina, and Upstate South
Carolina.

.DAY ONE...This afternoon and tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

GAZ018-026-028-NCZ057-070>072-SCZ004>010-072045-
Stephens-Franklin-Hart-Rowan-Gaston-Mecklenburg-Cabarrus-
Greater Oconee-Greater Pickens-Greater Greenville-Spartanburg-
Cherokee-York-Anderson-
340 PM EST Sat Feb 6 2021

This Hazardous Weather Outlook is for locations along and near the
I-85 corridor in northeast Georgia, Piedmont North Carolina, and
Upstate South Carolina.

.DAY ONE...This afternoon and tonight.

A period of a sleet and snow mix is expected tonight along and near
the Interstate 85 corridor. If the wintry mix lasts long enough, a
light accumulation is possible, which would lead to slippery road and
bridges overnight.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

HG