Hail and Damaging Wind in South Carolina, May 10, 2018

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
517 PM EDT Thu May 10 2018

.SYNOPSIS...
Showers and thunderstorms continue through this evening as a cold
front crosses the area. Mainly mountain afternoon and evening
thunderstorms are expected Friday and Saturday. Temperatures will
increase to near record levels by Sunday then slowly cool through
next week. Precipitation chances gradually increase through next
week as a complex low pressure system impacts the area.

&&

.NEAR TERM /THROUGH FRIDAY/...
As of 505 PM EDT: over the past couple of hours, we've been watching
a line of fairly strong convection move eastward from the higher
terrain. The strongest cells have developed over the NC Foothills
and have produced large hail and gusty winds. The the latest runs of
the CAMS have slowed the progression of this line down by a couple
of hours or so compared to earlier runs. Otherwise, the main
convection should exit east of the area by 01Z or so. Isolated
showers may continue to arrive in the northwest flow across the
southwest mountains through midnight before dissipating. Locations
receiving heavy rain this afternoon/evening, as well as the mountain
river valleys, could well see fog and low clouds toward daybreak
Friday. Mild mins should run 5 to 10 degrees above climatology.

Flat mid-upper ridging will develop over the southeast on Friday,
but a very weak H5 trough embedded in the ridge could provide weak
afternoon forcing over the NC mountains. A weak lee trough should
develop just east of the Blue Ridge as well to toggle winds back
toward southwesterly. Anticipate max temps warming at least a couple
of degrees above Thursday values, with isolated to scattered diurnal
convection focused mainly along the eastern slopes of the
mountains.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
As of 215 PM EDT Thursday: Weak upper shortwave will be passing
across the area, embedded in the flow atop the Gulf/Caribbean upper
ridge, at the beginning of the period. Any lingering convection from
Friday night should dissipate quickly on the back side of the wave.
For Saturday afternoon, continued mid-level warming with the upper
ridge in place and a weak surface trough in place should continue
the low-level WAA, resulting in afternoon highs a couple of degrees
warmer than what we'll see on Friday, with just about everywhere
across the Piedmont progged to reach the 90-degree mark. Without
upper support, convection will be limited to just the airmass
instability and mechanical lift from the mountains, so have dropped
most of the pops from the Piedmont. Thicknesses will increase
further still on Sunday as a broad upper trough remains in place
over E Canada and ridging amplifies over the center of the country.
The big story here will be the record-level highs; currently have a
record forecast for CLT, which will break a record that has been in
place for 137 years! Luckily dewpoints won't be ridiculous, so, so
far, no real concerns with heat indices. Very little change in low
temps through the period (actually, through the extended,
too...maybe fluctuating by 5 degrees through the end of next week).
Mid-level warming/subsidence will continue to increase, and this
will significantly limit convective potential even over the
mountains, with only some pockets of slight chance pops forecast at
this time.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 230 PM EDT Thursday: Still no major changes to the extended
from previous forecasts. With the subtropical ridge continuing in
place, Monday should be very similar to Sunday, maybe a degree or
two cooler, and with slightly more convection especially over the
mountains, but cannot rule out isolated activity over the Piedmont
as well.

Things start changing as we move into Tuesday and through the rest
of the period. A tropical weakness in the Gulf will strengthen just
slightly on Sunday, spinning near the FL Big Bend on Monday and
beginning to drift north into the Southeast Monday night and
Tuesday. Increasing cloud cover and precip chances will be expected,
and a corresponding decrease in afternoon highs (still above normal
though). From Tuesday through the end of the period, it looks fairly
wet...though QPF amounts aren't particularly impressive, low-level
moisture will remain high and thus higher pops are warranted, with
the best chances Wednesday afternoon where we have likely pops
painted across the area. Airmass instability will remain but lapse
rates in the tropical environment unimpressive, so some question as
to how much showery vs. thundery activity there will be. A shortwave
trough pushing toward the OH Valley at the end of the period will
slowly absorb the tropical low, but the tropical moisture feed from
the western Caribbean will continue so chance pops remain in the
forecast, with highs remaining 3-5 degrees above normal.

&&

.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
At KCLT and Elsewhere: There is reasonably good consensus on the
foothills convection developing into a broken line across the NC
piedmont late this afternoon and impacting KCLT mainly from 21Z to
23Z. Reasonably good cold pool winds of 25 to 30 kt should be
expected from the WNW, and gusts could reach quite a bit higher if
the convective strength builds into the stronger piedmont DCAPE
area. Convection should be a bit spottier elsewhere, with KHKY to
KAVL seeing the next best chance, but more scattered activity across
the Upstate terminal area. Will handle with mainly a VCTS in
southern sections. Any restrictions through the evening hours will
be brief MVFR to possibly IFR under the heaviest downpours.

Any locations that receive rain late today will be a candidate for
fog/stratus development toward daybreak Friday. Chances appear best
at KCLT and also in the mountain river valleys. Will remain fairly
conservative for now given the reserved MOS forecasts, but will
definitely hint that way at KCLT with some morning SCT007 along with
MVFR fog. Convective coverage should be quite a bit less on Friday,
with no mention before 18Z throughout, and nothing after 18Z at
KCLT. Winds will toggle back to SW with lee troughing early Friday,
except mainly NW at KAVL.

Outlook: Isolated to scattered diurnal convection will likely return
mainly over the higher terrain on Friday afternoon and into the
weekend. Any restrictions should be confined to areas under
showers/thunderstorms or daybreak fog/stratus in the lower mountain
valleys.

Confidence Table...

            21-03z        03-09Z        09-15Z        15-18Z
KCLT       High 100%     High 100%     Low   47%     High 100%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High 100%     High 100%     Low   47%     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

&&

.CLIMATE...
RECORDS FOR 05-10

               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      89 1936     53 1924     65 1927     32 1966
                1896                                1906
   KCLT      94 1896     59 1966     70 1927     38 1906
                1889
   KGSP      96 1889     56 1924     71 1895     32 1906

RECORDS FOR 05-11

               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      89 1889     50 1960     64 1890     30 1966
   KCLT      95 1916     58 1924     70 1889     39 1977
                1896
                1889
   KGSP      96 1889     59 1924     69 1963     33 1906

RECORDS FOR 05-12

               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      88 1980     44 1960     65 1918     36 1969
                1956
                1914
   KCLT      94 1889     56 1960     69 1896     39 1969
   KGSP      99 1916     56 1960     68 1979     38 1989
                                        1933
RECORDS FOR 05-13

               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      90 1933     54 1917     67 1890     31 1895
   KCLT      93 1881     59 1891     73 1881     38 1960
   KGSP      95 1886     62 1972     71 1933     37 1917
                            1954
                            1938

RECORDS FOR 05-14

               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      89 1956     52 1954     63 1962     30 1895
                1896                    1908
   KCLT      95 1956     53 1954     73 1881     41 2013
                                                    1917
   KGSP      95 1886     52 1954     71 1933     41 2013
                                                    1960
                                                    1917

&&

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

&&

SYNOPSIS...RWH
NEAR TERM...JPT
SHORT TERM...TDP
LONG TERM...TDP
AVIATION...HG/JPT
CLIMATE...TDP

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
431 PM EDT Thu May 10 2018

GAZ010-017-018-NCZ033-048>053-058-059-062>065-501>506-SCZ001>006-
112045-
Rabun-Habersham-Stephens-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-Oconee Mountains-
Pickens Mountains-Greenville Mountains-Greater Oconee-
Greater Pickens-Greater Greenville-
431 PM EDT Thu May 10 2018

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

.DAY ONE...Tonight.

Scattered to numerous thunderstorms are developing ahead of a cold
front approaching from the west this afternoon. Some of the
thunderstorms could become severe over the foothills and especially
the piedmont through early this evening. Cloud-to-ground lighting,
briefly heavy rainfall, and gusty winds can be expected with any of
these storms. Some of the strongest thunderstorms will be capable of
producing quarter-sized hail and damaging wind gusts. The storms
should move away to the east by around sunset.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

..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.
..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.

.SPOTTER INFORMATION STATEMENT...

Skywarn spotters are requested to forward any reports of large hail,
damaging winds, tornadoes, or flash flooding to our office.

NCZ035>037-056-057-068>072-082-507>510-SCZ007>009-013-014-112045-
Alexander-Iredell-Davie-Catawba-Rowan-Cleveland-Lincoln-Gaston-
Mecklenburg-Cabarrus-Union-Rutherford Mountains-Greater Rutherford-
Polk Mountains-Eastern Polk-Spartanburg-Cherokee-York-Chester-
431 PM EDT Thu May 10 2018

...SEVERE THUNDERSTORM WATCH 80 IN EFFECT UNTIL 10 PM EDT THIS
EVENING...

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

.DAY ONE...Tonight.

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

   Severe Thunderstorm Watch.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

..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.
..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.

.SPOTTER INFORMATION STATEMENT...

Skywarn spotters are requested to forward any reports of large hail,
damaging winds, tornadoes, or flash flooding to our office.

GAZ026-028-029-SCZ010>012-019-112045-
Franklin-Hart-Elbert-Anderson-Abbeville-Laurens-Greenwood-
431 PM EDT Thu May 10 2018

This Hazardous Weather Outlook is for northeast Georgia and upstate
South Carolina.

.DAY ONE...Tonight.

Scattered thunderstorms are developing ahead of a cold front
approaching from the west. Cloud-to-ground lighting, briefly heavy
rainfall, and gusty winds can be expected with any of these storms.
One or two of the thunderstorms may become strong enough to produce
large hail and damaging wind gusts. The storms should move away to
the east by around sunset.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

..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.
..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.

.SPOTTER INFORMATION STATEMENT...

Skywarn spotters are requested to forward any reports of large hail,
damaging winds, tornadoes, or flash flooding to our office.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
523 PM EDT THU MAY 10 2018

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

0505 PM     TSTM WND DMG     4 SSE COLUMBUS          35.19N 82.18W
05/10/2018                   POLK               NC   EMERGENCY MNGR

            TREES DOWN ON I-26. ONE ON A TRACTOR TRAILER. INTERSTATE
            SHUT DOWN.

0505 PM     TSTM WND DMG     3 SSE COLUMBUS          35.21N 82.18W
05/10/2018                   POLK               NC   EMERGENCY MNGR

            TREES DOWN ON I-26, ONE ON A TRACTOR-TRAILER. INTERSTATE
            IS SHUT DOWN.

&&

TPALMER

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