Severe Thunderstorm Warning 41, NWS Greenville-Spartanburg, SC

660 
WWUS52 KGSP 211914
SVSGSP

Severe Weather Statement
National Weather Service Greenville-Spartanburg SC
314 PM EDT MON MAY 21 2018

NCC027-211924-
/O.CAN.KGSP.SV.W.0041.000000T0000Z-180521T1930Z/
Caldwell NC-
314 PM EDT MON MAY 21 2018

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN CALDWELL COUNTY
IS CANCELLED...
        
The storm which prompted the warning has moved out of the area.
Therefore the warning has been cancelled.

LAT...LON 3610 8152 3610 8150 3609 8147 3609 8145
      3607 8144 3608 8142 3606 8140 3605 8140
      3600 8147 3603 8157 3612 8159 3612 8155
TIME...MOT...LOC 1913Z 200DEG 1KT 3609 8151 

$$

SGL

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
242 PM EDT Mon May 21 2018

.SYNOPSIS...
A moist air mass will remain in control of our weather through at
least Tuesday, bringing a continued high chance of showers and
storms in the afternoon and evening. A weak front sliding down on
Thursday may allow for some brief drying toward the end of the work
week. Expect another round of tropical moisture to lift across the
area from the Gulf for the weekend.

&&

.NEAR TERM /THROUGH TUESDAY/...
As of 230 PM: Destabilization is underway across the area, though
cu field remains very spotty over the Upstate, where SBCAPE is
smallest on SPC mesoanalysis, and dewpoints remain relatively
low. Over the mountains and I-40 corridor, however, moisture
pooling near a weak sfc boundary has resulted in more instability
and more frequent initiation. Still looks like t-storm chances
are best in these areas; another PoP update has been completed to
highlight this. That said, we can't rule out an isolated shower
or even t-storm over the southern half of the area. Max temps are
on track to top out a little above normal.

This evening and overnight, we will see a steady S to SW flow
continue across the area, as 500mb heights fall slightly with
a shortwave entering the Ohio Valley. Several guidance sources
develop light showers over the southern part of the area this
evening as 850mb moisture advection increases, though forcing
really remains rather weak overall. Activity should diminish after
midnight, but we'll retain a slight chance in all zones since we've
seen a few nocturnal showers each night in this moist pattern. By
morning models begin to key on the enhanced upslope lift over the
western third of the area, increasing PoPs earlier than the diurnal
curve. Overall, given rebounding dewpoints and ever so slightly
better lapse rates aloft thanks to that shortwave, precip chances
are much better than those today: likely for the western half of the
area and a nearly 50/50 chance over our east. Mean PWAT anomalies
from the SREF rise above 1 SD for the whole area, with parts of
the Piedmont above 2 SD. Given weak storm motion vectors, weakly
organized clusters of cells producing heavy rain will continue to
be our main concern from the developing convection. Max temps will
be near normal in the east and slightly below normal elsewhere
due to cloud cover.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
As of 210 pm Monday: Frontal zone/pre-frontal trough will ooze
into/across the forecast area on Wednesday, providing the primary
focus for diurnal convective development, supporting 40-60 pops
across the area during the afternoon and early evening. Moderate
CAPE and weakly sheared environment will support a localized pulse-y
severe threat as well as the potential for additional localized
hydro issues in locations that have poor antecedent conditions.

On Thursday, short term guidance pushes the lower theta-e/post
frontal air mass more solidly into the forecast area, supporting
lower coverage of diurnal convection, especially across northern
areas. Nevertheless, ingredients are sufficient to support 20-40
pops across much of the area during the afternoon/evening. Max temps
will be a couple of degrees above climo and min temps about 5
degrees above climo through the period.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 225 pm Monday: Weak boundary will remain over the area early
in the forecast period, possibly providing focus for another round
of diurnal convection on Saturday. Meanwhile, the axis of the upper
ridge is forecast to build over the area during the weekend, while
some guidance builds the low theta-e air mass associated with
Bermuda high-associated surface ridge into the Carolinas. Although
this would argue for less overall coverage of diurnal convection,
there are also indications that a SE upslope flow may develop as
well. Therefore, diurnal convective chances are maintained Sat
afternoon/evening.

For late in the weekend into early next week, much depends upon how
tropical weather will evolve over the next few days, specifically
regarding the area of disturbed weather currently located across the
western Caribbean. There is a decent consensus among the ECMWF and
Canadian global models (as well as the GFS ensemble system) that a
tropical cyclone will be in the vicinity of the lower Miss Valley on
Sunday. These guidance sources also depict a rather large shield of
moisture associated with the cyclone, which would possibly impact
our area for Days 6/7. For the time being, this will be reflected in
the current official forecast as enhanced chances (generally 60-70%)
for mainly diurnal convection Sunday afternoon into Monday evening.
However, forecast trends will need to be monitored closely for a
potentially more organized heavy rainfall threat early next week.
Otherwise, temps are forecast to remain above normal through the
period.

&&

.AVIATION /19Z MONDAY THROUGH SATURDAY/...
At KCLT and elsewhere: TSRA this afternoon are most likely
along and north of Interstate 40. This warrants VCTS for
KAVL/KHKY. Elsewhere a few SHRA could occur though impacts should
be low. Light southerly low-level flow will continue tonight and
could produce evening showers over the SC sites and KCLT. Again,
impacts from these are not expected to be remarkable except
perhaps brief MVFR vsby. While the aforementioned flow will bring
additional moisture overnight, forcing will be very limited, and
guidance expectations for low clouds look overdone. Only the more
southerly sites, KGSP/KGMU/KAND, are expected to see restrictions
from stratus. Following persistence, KAVL looks to experience
fog development again. Convective chances across the area will be
notably higher on Tuesday, given the return of better sfc moisture
and slightly better midlevel lapse rates. This warrants SHRA VCTS
at some sites, and PROB30 TSRA at others.

Outlook: The unsettled pattern will continue the rest of the week,
with flight restrictions possible each day under periodic showers
and thunderstorms. Morning stratus/fog are possible especially
following heavy rain the previous day.

Confidence Table...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       High 100%     High 100%     High 100%     High  97%
KGSP       High 100%     High 100%     High  95%     High  91%
KAVL       High 100%     High  97%     Med   62%     Med   76%
KHKY       High 100%     High 100%     High  96%     High  92%
KGMU       High 100%     High 100%     High  95%     High  89%
KAND       High 100%     High 100%     High  93%     High  87%

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...DEO
NEAR TERM...Wimberley
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...Wimberley

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
546 AM EDT Mon May 21 2018

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-221000-
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-
546 AM EDT Mon May 21 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...Tuesday through Sunday.

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

.SPOTTER INFORMATION STATEMENT...

None.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1144 AM EDT MON MAY 21 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1000 PM     DEBRIS FLOW      3 E LAKE LURE           35.43N 82.16W
05/18/2018                   RUTHERFORD         NC   911 CALL CENTER

            THE VERY HEAVY RAIN CAUSED SOME MINOR MUDSLIDES IN THE
            BILLS CREEK AREA THAT DID NOT AFFECT ANY STRUCTURES.

&&

OUTLAW

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
124 PM EDT MON MAY 21 2018

NCZ501-211800-
Caldwell Mountains NC-
124 PM EDT MON MAY 21 2018

...A STRONG THUNDERSTORM WILL IMPACT NORTH CENTRAL CALDWELL COUNTY
UNTIL 200 PM EDT...

At 124 PM EDT, Doppler radar was tracking a strong thunderstorm 5
miles east of Blowing Rock, or 4 miles west of Darby. This storm was
nearly stationary.

Locations to be impacted include...
Blowing Rock In Caldwell County and Upton.

Wind gusts up to 40 mph and pea size hail will be possible in these
areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

The combination of gusty winds and saturated soil conditions will
cause scattered trees and power lines to fall. Seek shelter inside an
interior room.

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 3612 8155 3610 8152 3610 8149 3603 8151
      3600 8165 3612 8172
TIME...MOT...LOC 1724Z 165DEG 4KT 3611 8158

SGL

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
200 PM EDT MON MAY 21 2018

NCZ501-211830-
Caldwell Mountains NC-
200 PM EDT MON MAY 21 2018

...A THUNDERSTORM WITH TORRENTIAL RAINFALL WILL IMPACT NORTH CENTRAL
CALDWELL COUNTY UNTIL 230 PM EDT...

At 200 PM EDT, Doppler radar was tracking a thunderstorm with
torrential rainfall near Blowing Rock, or near Blowing Rock In
Caldwell County. This storm was nearly stationary.

Locations to be impacted include...
Blowing Rock In Caldwell County and Upton.

Wind gusts up to 40 mph and pea size hail will be possible in these
areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

The combination of gusty winds and saturated soil conditions will
cause scattered trees and power lines to fall. Seek shelter inside an
interior room.

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 3612 8155 3610 8152 3610 8149 3603 8151
      3602 8166 3612 8171
TIME...MOT...LOC 1800Z 186DEG 2KT 3611 8161

SGL