Freeze Warning 8, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
352 AM EDT Sun Mar 19 2017

.SYNOPSIS...
Dry high pressure will build into the region today, and settle over
the Southeast states through Monday. Another cold front will
approach the forecast area Tuesday into Wednesday, increasing
chances for rain and thunderstorms.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 330 AM EDT: Low clouds and isolated very light snow showers
will linger across the mountains through daybreak. The snow showers
end after daybreak but the clouds will only slowly dissipate through
the day. Low clouds will spill out of the mountains and across the
foothills and piedmont early this morning and dissipate by
afternoon. Gusty N to NW winds will also continue across the area
through the morning then slowly diminish through the afternoon. The
highest peaks may see some advisory level wind gusts, but they
should remain below advisory level elsewhere, even with some
occasional stronger gusts from time to time. Highs will be around 5
degrees below normal as a cooler and drier air mass moves in.

The center of surface high pressure builds in and settles across the
area tonight. This leads to a relaxed pressure gradient and light
and variable winds. There could be a little cirrus from time to time
overnight keeping lows from bottoming out. Even so, guidance shows
lows falling to around 5 degrees below normal. Local COOP MOS
suggests lows could even be colder in some areas. Therefore, will
trend to the pessimistic side and issue a Freeze Warning for the NC
Northern Foothills, NW Piedmont, and Rutherford, Cleveland, Lincoln,
and Cabarrus Counties. Will issue a Frost Advisory for the rest of
the non-mountain counties. Cannot rule out a freeze in the normally
colder or more sheltered locations in the advisory, and the warning
may need expanding later in response.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
As of 300 AM EDT Sunday: an broad upper trough will cross the
Northern Plains on Monday, then dig as it enters the Great Lakes on
Tuesday. After a cool start to the day Monday morning, temps will
rebound to about 5 degrees above normal under mostly sunny skies. A
front will push into the Ohio Valley on Monday, then slow down as it
approaches the CWFA Monday night. Model guidance agrees that the air
mass south of the front will become moderately unstable, with
showers and storms just to our NW Monday, some of which will move
into the NC mountains overnight. Confidence is not real high that
much of that activity will survive over the mountains, so PoPs will
remain confined to the mountains. Lows will be well above normal.

Tuesday, there will be a weak low pressure wave that will try to
develop along the front as it pushes into NC from the north. This
may enhance SWLY flow across GA and the Upstate and pool some
mid-upr 50 dewpts. This in combination with steep mid-level lapse
rates may result in 1000-2000 J/kg of SBCAPE by late afternoon.
Forcing will remain modest at best, as most of the better DPVA will
remain north of the area. Still expect scattered to numerous showers
and tstms to develop along and ahead of the front as it lays over
the area Tuesday afternoon and evening. Severe storms may be
possible, as 0-6 km bulk shear will be 30-40 kts along the front. A
marginal risk has been added to the Day 3 Convective outlook by SPC
for portions our western 2/3rds of the area. Highs will be well
above normal as the front approaches, with mid 70s to lower 80s
across most of the piedmont.

Tuesday night, the front will sag south thru the area with
convection shifting south. However, lift will linger atop the
frontal zone, so PoPs will be slow to decrease overnight. Temps will
remain well above normal under clouds and precip.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 330 AM Sunday: a large and fairly strong area of high pressure
will drop southeast into Great Lakes and push the front south of the
area on Wednesday. The high will bring thicknesses down as cold air
damming develops east of the mountains. It's uncertain how much
clearing there will be, as the GFS shows lingering low-level
moisture and bringing the flow around out of the east. Highs will be
at or slightly below normal.

An upper ridge will track east across the CONUS Thursday and set up
along the East Coast on Friday. Then a trough will eject out into
Plains on Saturday. The surface high will migrate off the
Mid-Atlantic coast and keep a wedge across the area Thursday and
Friday. Southerly upglide flow will set up atop the wedge and keep
the forecast area mostly cloudy with a gradual increase in PoPs. The
medium range guidance is now advertising a split in the trough, with
the southern stream trough possibly closing off into an upper over
the lower Mississippi Valley. This results in a delayed arrival of
the next front, which was expected to push into the area on
Saturday. Either way, the upcoming weekend does look unsettled with
chance to likely PoPs and cool temps.

&&

.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
At KCLT and Elsewhere: Returning low level moisture from the
northwest will produce some upslope cloudiness in the western
mountains, with VFR cigs this morning at KAVL. The clouds will spill
out of the mountains with VFR cigs at KHKY and sct to few elsewhere.
KCLT could see a brief cig through daybreak. N to NW winds will
continue through daybreak then become gusty after daybreak. KAVL
will see very gusty winds through the afternoon. The low clouds
scatter out through the afternoon leaving only cirrus for the
evening. Winds turn NNE and taper off during the evening.

Outlook: A drier airmass will return behind the front through at
least Monday. Another cold front may bring scattered showers and
perhaps a few thunderstorms on Tuesday, and possibly into Wed.

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

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...Frost Advisory from midnight tonight to 9 AM EDT Monday for
     GAZ018-026-028-029.
NC...Frost Advisory from midnight tonight to 9 AM EDT Monday for
     NCZ070-071-082-510.
     Freeze Warning from midnight tonight to 9 AM EDT Monday for
     NCZ035>037-056-057-068-069-072-502-504-506-508.
SC...Frost Advisory from midnight tonight to 9 AM EDT Monday for
     SCZ004>014-019.

&&

SYNOPSIS...ARK
NEAR TERM...RWH
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...RWH

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
711 PM EDT Sat Mar 18 2017

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-192315-
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-
711 PM EDT Sat Mar 18 2017

This Hazardous Weather Outlook is for northeast Georgia, piedmont
North Carolina, western North Carolina and Upstate South Carolina.

.DAY ONE...Tonight.

No hazardous weather is expected at this time.

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

..Sunday...No hazardous weather is expected at this time.
..Monday...No hazardous weather is expected at this time.
..Tuesday...No hazardous weather is expected at this time.
..Wednesday...No hazardous weather is expected at this time.
..Thursday...No hazardous weather is expected at this time.
..Friday...No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

HG