Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
101 AM EST Mon Mar 1 2021

.SYNOPSIS...
A cold front will cross the mountains early this morning and then
cross the foothills and Piedmont through the late morning and early
afternoon hours. Dry high pressure will build over from the north
tonight into Tuesday. Unsettled weather returns from the west
Tuesday night into Wednesday morning. Another low pressure system
may affect the Gulf Coast region Friday into Saturday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 1245 am EST: The latest surface analysis reveals a cold front
positioned roughly from Knoxville to Chattanooga TN early this
morning and making slow progress eastward toward the NC mountains.
Ahead of this boundary, gusty southwest winds have developed over
the higher terrain, but with max gusts likely staying just below
advisory values of 45 mph along the highest ridge tops.
Precipitation will begin to fill in quickly across the NC mountains
as the frontal zone and associated H5 vorticity reach the spine of
the southern Appalachians circa 09Z, march on to the Blue Ridge
Mountains eastern escarpment by 11Z, then move east across the
foothills/Piedmont through late morning. The PoP trends will follow
this pattern, with categorical coverage likely at some point for
most locations, but with QPF values much better along the TN border
areas early this morning, and particularly across Graham and Swain
Counties in the best upslope flow and longest dwelling period of the
heavy rainfall. With QPF values around 1.5+ inches in these areas,
minor hydro problems could arise, but this should not be sufficient
for any widespread flooding and a Flash Flood Watch does not appear
to be needed. Instability remains quite marginal in profiles. Will
generally keep thunder out of the forecast, but an isolated rumble
cannot be completely ruled out with the fropa.

Temperature trends will be hard to pin down today, with falling
temps likely in the cold advection across the mountains, steady
temperatures across the northern tier in balanced cold advection but
warming post-fropa downslope flow, and a modest afternoon bump in
temps in the western Upstate and NE GA. Gusty northwest winds will
also develop in the cold advection through the day, but with gust
values again below advisory criteria in the windiest mountain
locations where a secondary, reinforcing cold fropa arrives this
afternooon. A trailing but vigorous shortwave will reach the
mountains again by late day. However, the deeper moisture should
settle generally southeast of our Piedmont counties by sundown along
with the passing cold front. Any shallow upslope moisture into the
western mountains will dry up fairly quickly in the cold air along
the spine of the mountains this evening. So, any isolated snow
showers or flurries will be short-lived and non-accumulating.
1032 mb surface high pressure will then build over the OH River
valley tonight, with chilly thicknesses spilling southward east of
the Appalachians.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
As of 1205 pm EST Sunday: As sfc ridging rolls over into the region
Monday night, the llvls will continue to dry, but model cross
sections depict varying degrees of mid and upper level moisture
lingering within the west to wsw flow aloft.  Gridded model sky
cover solutions are all over the place, and at this point, the
generic partly cloudy should cover it.  Downstream of developing
southern stream low pressure, clouds should thicken again as Tuesday
wears on and within the cool NE llvl flow, maximum temperatures will
be back to below climo values.

From late day Tuesday into Wednesday morning, as forcing and better
moisture asscoiated with the encroaching southern stream system
overspreads the region, pcpn will be become widespread.  Vertical
temperature/moisture fcst profiles over the NC mtns still suggest
that a period of snow developing into a wintry mix remains possible
during this time.

Fast moving s/wv passage is expected on Wednesday, the axis of which
is timed to be near the coast by the afternoon.  Whatever the
orientation and cvrg of pcpn shield is in the morning should be
replaced by dry slotting by Wed afternoon.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 1215 pm EST Sunday: No change to the going dry and mild fcst
for Thursday as extended range guidance remains in good agreement in
progging deep layered dry air within the cyclonic flow aloft and a
dry northerly llvl flow.  Within the lingering llvl northerly flow,
a dry cold front is progged drop south through the region on Friday
ushering in another period of below climo temperatures.

The mean pattern does not change very much for next weekend,
featuring a lingering eastern CONUS trough.  Forcing rounding the
base of upper trough is progged to activate baroclinic zone, but way
off to our south and into the offshore Atlantic on Saturday into
Sunday.  The dry conditions will continue with temperatures around 5
deg F below the early March climo each day.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
At KCLT and elsewhere: Anticipate mainly thickening and lowering VFR
ceilings early this morning as a cold front and associated deeper
moisture moves in from the west. The narrow band of frontal moisture
should provide MVFR to lower end VFR cigs during the passsage of the
main bands of rain showers with the front, generally from just
before daybreak west to mid-morning east. VFR cigs will then lift
and scatter through the afternoon hours, with just FEW to SCT high
clouds tonight as drier high pressure builds in from the north.
Gusty southwest flow this morning will become slightly gustier W to
NW flow this afternoon following fropa and the onset of cold
advection. Most locations lose the gusts by early evening, but KAVL
will be the exception with continued NW gusts into the 20s through
06Z Tuesday.

Outlook: VFR conditions briefly persist into Tuesday under dry high
pressure. However, moisture may surge back into the area by Tuesday,
with restrictions and precipitation chances returning through early
Wednesday. Another round of drying is expected by late Wednesday,
likely continuing through the end of the work week.

Confidence Table...

            06-12Z        12-18Z        18-24Z        00-06Z
KCLT       High 100%     High  95%     High 100%     High 100%
KGSP       High  95%     High  93%     High 100%     High 100%
KAVL       High  85%     High  96%     High  99%     High 100%
KHKY       High  99%     High 100%     High 100%     High 100%
KGMU       High  95%     High  96%     High 100%     High 100%
KAND       High  97%     High  94%     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 are available at
the following link:

www.weather.gov/gsp/aviation

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.

&&

SYNOPSIS...HG
NEAR TERM...HG
SHORT TERM...CSH
LONG TERM...CSH
AVIATION...HG

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
1229 PM EST Sun Feb 28 2021

GAZ010-NCZ033-048>053-058-059-062>065-011730-
Rabun-Avery-Madison-Yancey-Mitchell-Swain-Haywood-Buncombe-Graham-
Northern Jackson-Macon-Southern Jackson-Transylvania-Henderson-
1229 PM EST Sun Feb 28 2021

This Hazardous Weather Outlook is for northeast Georgia and western
North Carolina.

.DAY ONE...This afternoon and tonight.

Heavy rain showers are expected to develop ahead of a cold front
approaching from the northwest tonight. The rainfall could be
sufficient for isolated flooding to develop in some locations toward
daybreak, especially across the far southwest mountains of western
North Carolina.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

Heavy rain showers, and isolated flooding, may linger into Monday
morning as a cold front crosses the region.

.SPOTTER INFORMATION STATEMENT...

None.

GAZ017-018-026-028-029-NCZ035>037-056-057-068>072-082-501>510-
SCZ001>014-019-011730-
Habersham-Stephens-Franklin-Hart-Elbert-Alexander-Iredell-Davie-
Catawba-Rowan-Cleveland-Lincoln-Gaston-Mecklenburg-Cabarrus-Union NC-
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-Union SC-Chester-Greenwood-
1229 PM EST Sun Feb 28 2021

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

.DAY ONE...This afternoon and tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

Lane

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
157 AM EST Mon Mar 1 2021

NCZ051-052-058-010800-
Haywood NC-Graham NC-Swain NC-
157 AM EST Mon Mar 1 2021

...HEAVY RAIN SHOWERS AND GUSTY WINDS WILL IMPACT SWAIN...GRAHAM AND
NORTHWESTERN HAYWOOD COUNTIES UNTIL 300 AM EST...

At 157 AM EST, Doppler radar indicated heavy rain showers along a
line extending from 12 miles east of Alcoa to 17 miles northwest of
Murphy, and moving east at 35 mph.

Locations to be impacted include...
Bryson City, Robbinsville, Town Of Santeetlah, Smoky
Mountains-Newfound Gap, Smoky Mountains-Fontana Area, Lake
Santeetlah, Smoky Mountains-Balsam Mountain, Fontana Lake, Smoky
Mountains-Big Creek and Fontana Village.

Wind gusts of 30 to 40 mph and heavy rainfall rates up to one
inch per hour will be possible in these areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Gusty winds can blow down trees that are dead, or that have weakened
root systems. Outdoor furniture and similar items can be tossed
around if not anchored. Seek shelter indoors.

&&

LAT...LON 3541 8402 3552 8388 3556 8377 3556 8350
      3566 8335 3566 8330 3573 8324 3579 8308
      3579 8296 3574 8295 3574 8292 3549 8315
      3552 8324 3547 8335 3533 8334 3528 8367
      3525 8370 3525 8385 3522 8396 3523 8400
TIME...MOT...LOC 0657Z 288DEG 31KT 3577 8375 3528 8423

HG