Severe Thunderstorm Warning 40, NWS Greenville-Spartanburg, SC

466 
WWUS52 KGSP 201833
SVSGSP

Severe Weather Statement
National Weather Service Greenville-Spartanburg SC
233 PM EDT SUN MAY 20 2018

GAC241-SCC073-201900-
/O.CON.KGSP.SV.W.0040.000000T0000Z-180520T1900Z/
Rabun GA-Oconee SC-
233 PM EDT SUN MAY 20 2018

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 300 PM EDT
FOR EAST CENTRAL RABUN AND NORTHWESTERN OCONEE COUNTIES...

At 232 PM EDT, a severe thunderstorm was located 10 miles east of
Clayton, or 6 miles west of Oconee State Park, moving south at 15
mph.

HAZARD...60 mph wind gusts and penny size hail.

SOURCE...Radar indicated.

IMPACT...Expect damage to trees and power lines.

Locations impacted include...
Pine Mountain, Mountain Rest, Long Creek and Oconee State Park. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Scattered trees and power lines will be blown down in the warned
area. Seek shelter inside an interior room.

This storms is also producing extremely heavy rainfall. Flooding of
drainage ditches and low lying areas may occur. Small streams will
rise rapidly. Do not drive through areas where water is flowing over
the road.

Please report damaging winds, hail, or flooding to the National
Weather Service Greenville-Spartanburg by calling toll free, 1, 800,
2 6 7, 8 1 0 1, or by posting on our Facebook page, or Tweet it using
hashtag nwsgsp. Your message should describe the event and the
specific location where it occurred.

&&

LAT...LON 3490 8334 3496 8313 3494 8312 3472 8308
      3466 8330
TIME...MOT...LOC 1832Z 342DEG 12KT 3486 8322 

HAIL...0.75IN
WIND...60MPH
 
$$

ARK

006 
WWUS52 KGSP 201853
SVSGSP

Severe Weather Statement
National Weather Service Greenville-Spartanburg SC
253 PM EDT SUN MAY 20 2018

GAC241-SCC073-201903-
/O.EXP.KGSP.SV.W.0040.000000T0000Z-180520T1900Z/
Rabun GA-Oconee SC-
253 PM EDT SUN MAY 20 2018

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL RABUN AND
NORTHWESTERN OCONEE COUNTIES WILL EXPIRE AT 300 PM EDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore the warning will be allowed to expire.  However small hail,
gusty winds and heavy rain are still possible with this thunderstorm.

If you observed large hail or wind damage, please report it to the
National Weather Service Greenville-Spartanburg by calling toll free,
1, 800, 2 6 7, 8 1 0 1, or by posting on our Facebook page, or Tweet
it using hashtag nwsgsp. Your message should describe the event and
the specific location where it occurred.

LAT...LON 3490 8334 3496 8313 3494 8312 3472 8308
      3466 8330
TIME...MOT...LOC 1853Z 357DEG 14KT 3479 8322 

$$

ARK

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
151 PM EDT Sun May 20 2018

.SYNOPSIS...
A persistent southerly flow will maintain a tropical-like moist
atmosphere atop the region through at least Tuesday.  This will
result in a continued high chance of showers and storms each
afternoon and evening.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 145 PM EDT: Convection firing across the ridgetops as
expected by the early warmup and destabilization across the
mtns. The convection should gradually expand eastward on a diet of
sbCAPE on the order of 3000 J/kg just east of the Blue Ridge this
afternoon. However, the mesoanalysis bears out the suppressing
effects of some thicker high clouds over the Piedmont and Upstate
in a corridor between the mtns and the convection firing over the
SC Midlands. Still think there is time for the high clouds to thin
out enough and for convection to eventually develop in the I-85
corridor, as indicated by the 12Z HREF.

Otherwise, an upper trough will continue to lift north and deamplify
as its axis moves NE of the CWFA. At the sfc, the subtropical
Bermuda High will continue to maintain control of the synoptic
pattern over the Southeast CONUS. Although we don't expect a
significant change in the moist airmass that has prevailed over
our area, the latest guidance depicts slightly drier air and less
convective coverage today compared to the last few days. Highs
will climb into the low to mid 80s across the lower terrain and
mid to upper 70s across the higher terrain.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
As of 230 AM EDT Sunday: The subtropical upper low will remain in
place over the Deep South as we begin the short term period, while
the surface high in the Atlantic will continue the low-level
warm/moist southerly feed. The upper low will weaken and work slowly
north through the period as the longwave pattern tries to absorb it,
but the upper flow over the Southeast will be so weak that the
weakness will sort of just sit across the area through the period.
Convection will be mainly diurnal in nature, but enhanced by the
upper low. CAPE values will be minimized by the weak lapse rates,
but generally between 1000-1500J/kg each day. Tuesday afternoon
looks a little curious as the surface pattern is resembling the
development of a bit of insitu damming, though not reflected in the
surface winds which remain out of the south, and guidance is
lowering max temps a couple of degrees accordingly. High PWs,
surface instability, convective precip rates combined with very
saturated soils will keep the flash flood threat in place.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 315 AM EDT Sunday: Upper high over the western Atlantic as
well as a building upper ridge up the Plains will be in place to
start the extended period. Broad upper trough over eastern Canada
will continue to try to absorb the weakening subtropical upper low
over the Southeast, but the two ridges will slowly begin to merge as
the Canadian upper trough strengthens and forces the Atlantic upper
high toward the Bahamas. A weak surface trough will be in place over
the Piedmont and will slide slowly south as we pass midweek,
swinging winds around to NW and eventually NE. Not much change in
temperatures as the airmass does not change despite the surface
trough. Convection will remain very diurnal in nature through still
enhanced by the Southeast upper weakness and like the short term
with PWs remaining high, lapse rates will be minimized. Severe
threat will remain low but isolated/localized flash flooding
concerns will remain through the period.

And then, as mentioned previously, things could get a tad more
complicated at the end of the period with global models wanting to
develop some sort of tropical system to impact the Southeast. Way
too far out for any details but naturally the concern would be the
continued increase in moisture as a result. Without much of a break
through the period, as mentioned in the WPC morning discussion, the
overall pattern is pointing to a heavier rainfall trend.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
At KCLT and elsewhere: Low clouds with bases generally in the
range of 020-025 continue to scatter out across the region
early this afternoon. Cannot rule out a brief MVFR ceiling away
from ongoing convection, but this detail will not be included
for brevity. Instead, prefer to employ a 3-4 hr TEMPO to handle
thunderstorm restrictions later this afternoon at all sites other
than KAND. The showers and storms should diminish fairly early
this evening with only convective debris beyond 23Z-01Z. Locations
that see rain this afternoon/evening will have a good chance at
a fog restriction in the pre-dawn hours Monday if recent past is
any indication. All sites get a short window of MVFR visibility
around daybreak to account for this. Otherwise, Monday looks to
be nearly a copy of today. Wind should remain light S/SW apart
from thunderstorm outflows today, then light/variable overnight,
and SW again Monday.

Outlook: The unsettled weather pattern will continue into the first
half of the week with flight restrictions possible each day around
isolated/scattered showers and storms.

Confidence Table...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       High 100%     High 100%     High  99%     High  91%
KGSP       High 100%     High 100%     High  94%     High  85%
KAVL       High 100%     High 100%     High  93%     High  98%
KHKY       High 100%     High 100%     High  92%     High  89%
KGMU       High 100%     High 100%     High  89%     High  81%
KAND       High  99%     High  99%     High  80%     High  81%

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...None.
NC...None.
SC...None.

&&

SYNOPSIS...CSH
NEAR TERM...JPT/PM
SHORT TERM...TDP
LONG TERM...TDP
AVIATION...PM

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
517 AM EDT Sun May 20 2018

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-210930-
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-
517 AM EDT Sun May 20 2018

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

.DAY ONE...Today and Tonight.

Isolated to scattered thunderstorms are expected to develop again
this afternoon and evening across the area, but most numerous across
the mountains. Severe thunderstorms are not expected, but brief heavy
rain with localized flash flooding, small hail, and lightning will
be possible. Gusty winds from thunderstorms could blow down a few
trees due to saturated soils.

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

..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.
..Saturday...No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
112 PM EDT SUN MAY 20 2018

GAZ010-NCZ062-201745-
Rabun GA-Macon NC-
112 PM EDT SUN MAY 20 2018

...A STRONG THUNDERSTORM WILL IMPACT NORTHWESTERN RABUN AND
SOUTHWESTERN MACON COUNTIES UNTIL 145 PM EDT...

At 111 PM EDT, Doppler radar was tracking a strong thunderstorm 12
miles southwest of Franklin, or 8 miles southeast of Nantahala Lake.
This storm was nearly stationary.

Locations to be impacted include...
Otto, Rainbow Springs and Wayah Bald.

Wind gusts up to 40 mph, dime size hail and very heavy rainfall rates
up to 2 inches 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.

Torrential rainfall may flood areas with poor drainage, such as
ditches and underpasses. Avoid these areas and do not cross flooded
roads. Water levels of small streams may also rise rapidly. Seek
higher ground if threatened by flood waters.

&&

LAT...LON 3519 8353 3508 8334 3490 8358 3493 8360
      3495 8355 3499 8355 3500 8348 3500 8352
      3502 8352 3504 8356 3507 8357 3509 8359
      3511 8362 3513 8362
TIME...MOT...LOC 1711Z 318DEG 2KT 3509 8356

ARK

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
115 PM EDT SUN MAY 20 2018

NCZ051-052-059-201745-
Haywood NC-Swain NC-Northern Jackson NC-
115 PM EDT SUN MAY 20 2018

...A STRONG THUNDERSTORM WILL IMPACT NORTH CENTRAL JACKSON...EAST
CENTRAL SWAIN AND WEST CENTRAL HAYWOOD COUNTIES UNTIL 145 PM EDT...

At 114 PM EDT, Doppler radar was tracking a strong thunderstorm 9
miles northwest of Waynesville, or near Smoky Mountains-Balsam
Mountain. This storm was nearly stationary.

Locations to be impacted include...
Lake Junaluska, Maggie Valley, B.R. Parkway-Smoky Mountains To Balsam
Gap, Smoky Mountains-Balsam Mountain and Smoky Mountains-Cataloochee.

Wind gusts up to 40 mph, pea size hail and very heavy rainfall rates
up to 2 inches 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.

Torrential rainfall may flood areas with poor drainage, such as
ditches and underpasses. Avoid these areas and do not cross flooded
roads. Water levels of small streams may also rise rapidly. Seek
higher ground if threatened by flood waters.

&&

LAT...LON 3557 8324 3566 8311 3554 8294 3542 8313
TIME...MOT...LOC 1714Z 324DEG 4KT 3556 8313

ARK

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
145 PM EDT SUN MAY 20 2018

NCZ049-505-201815-
McDowell Mountains NC-Yancey NC-
145 PM EDT SUN MAY 20 2018

...A STRONG THUNDERSTORM WILL IMPACT SOUTHWESTERN MCDOWELL AND
SOUTHEASTERN YANCEY COUNTIES UNTIL 215 PM EDT...

At 145 PM EDT, Doppler radar was tracking a strong thunderstorm 11
miles west of Marion, or near Old Fort. This storm was nearly
stationary.

Locations to be impacted include...
Old Fort, B.R. Parkway-Craggy To Little Switzerland and Busick.

Wind gusts up to 40 mph, pea size hail and very heavy rainfall rates
up to 2 inches 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.

Torrential rainfall may flood areas with poor drainage, such as
ditches and underpasses. Avoid these areas and do not cross flooded
roads. Water levels of small streams may also rise rapidly. Seek
higher ground if threatened by flood waters.

&&

LAT...LON 3577 8216 3560 8210 3555 8224 3556 8225
      3561 8227 3563 8227 3566 8229 3567 8228
      3568 8229 3570 8229 3570 8228 3571 8228
      3573 8230
TIME...MOT...LOC 1745Z 074DEG 1KT 3567 8222

ARK