Severe Thunderstorm Warning 102, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
243 PM EDT Sun Jun 4 2017

.SYNOPSIS...
Moisture will increase from the south through Monday. A cold front
will settle southward from the Great Lakes through Monday night and
cross the region on Tuesday. Slightly cooler and drier conditions
will develop behind the front from mid to late week.

&&

.NEAR TERM /THROUGH MONDAY/...
As of 235 PM EDT: Convection has been expanding across the CWFA over
the past few hours and will continue to do so thru the afternoon and
into the evening. Most thunderstorms should be sub-severe, however we
may get a few that produce larger hail and severe downburst winds.
Flash flooding will also be a concern thru the near-term period as
sct convection will likely persist well into the overnight and some
training is likely, with more precip expected tomorrow. Overall convective
coverage should gradually diminish later tonight. However, the moist
environment will persist, and a low-lvl jet of 25-30 kts is expected
to develop, which will act to maintain some degree of BL convergence.
Min temps will be at least 5 degrees above normal.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
As of 2pm Sunday: Rain continues Monday night into Tuesday as mid to
upper 60s dewpoints will still prevail, even as weak front passes
through part of the area late on Monday.  Front mostly serves to
veer wends to westerly, wtih main push of drier air into the area
not beginning until Tuesday afternoon when surface trough and front
begin a stronger push southward and northerly flow over the
mountains commences.  POPs will plummet behind the front Tuesday
afternoon, along with a ten degree drop in dewpoint.  Cloudiness on
Tuesday and post frontal airmass on Wednesday will keep temperatures
to at or below normal levels.

Main dynamical features of this system are well to the north, and
even with the FROPA on Tuesday, surface winds do not appear
particularly strong, with 850mb winds peaking at around 15 kts over
the mountains Tuesday night.  With clearing skies, light winds, and
moderate temperartures, Wednesday should be a nice change from the
rainly Monday and Tuesday.

With limited MLCAPE and meager wind shear,main issue is any sort of
localized flooding concerns.  Storm total QPF for Sunday through
Tuesday is currently anticipated at around an inch to an inch and a
half.  As PWAT is pretty high in soundings, and due to convective
nature of showers, there will be strong place-to-place variability
in rain placement, and some areas may receive quite a bit more or
less than the mean forecast.

There is definitely potential for heavy rainfall with convective
rates developing Monday and Monday night, but it remains difficult
to pin down any specific threat area as locations east of the Blue
Ridge are more unstable, but the western mountains will benefit from
westerly upslope flow and higher coverage. Will mention heavy rain
in the HWO, but no flood/flash flood watches are expected.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 155 PM EDT Sunday: Starting Wed evening, the back edge of
frontal precip over the Midlands of SC is moving out to the east as
the closed upper low wobbles over PA and begins to move off to the
east by late Thursday. Both the GFS and ECMWF agree that as the
upper trough axis crosses our forecast area mostly light rain or
showers break out Thursday afternoon along and east of the southern
Appalachians. All precip should dissipate before midnight and dry
weather expected through Friday morning. As the upper ridge builds
slowly east from the Rockies and across the Plains, shortwave energy
passes through the flow in a NW to SE movement. The low level flow
going into the weekend will be from a general southerly direction
but it will be rather weak. Moisture will recover a little each day
and mainly mountain convection is expected each PM through Sunday.
The upper ridge will be in place on Sunday from FL to the eastern
Great Lakes as the models have big differences on the rest of the
nations forecast.

Temperatures at least 5 degrees below normal Wed night through
Friday then rising to at least normal by Sunday.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
At KCLT and Elsewhere: increasing deep layer moisture and instability
will support a significant uptick in convective coverage thru the remainder
of the afternoon and evening. Convective coverage will spread across the
fcst area over the next several hours. All terminals carry TEMPOs for TSRA
for the next 4 to 8 hrs with prevailing SHRA after that. Convective
potential ramps back up later tomorrow morning, so I included PROB30
groups after roughly 12z to account for that potential. Winds should
remain out of the S to SW in the 6-10 kts range with intermittent gusts
in the vicinity of thunderstorms. Increasing moisture will pose more of
a risk of fog and/or low cigs tonight, and MVFR conditions are forecast
at most terminals after 06Z. IFR cigs are likely by the early morning so
I included them from roughly 08 to 12z, but of course they could linger
longer.

Outlook: As a cold front pushes farther into the area, there will be
continued chances for scattered to numerous convection through Monday night,
with chances gradually tapering off during the day Tuesday. There will also
be increasing chances for early morning fog and/or low stratus, especially
over the mtn valleys. Drier air and NLY flow is expected to return behind
the cold front on Wednesday.

Confidence Table...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       High 100%     High 100%     Med   72%     High  81%
KGSP       High 100%     High  92%     Med   61%     High  84%
KAVL       High 100%     Med   69%     Low   49%     High  87%
KHKY       High 100%     High  99%     Med   73%     High  82%
KGMU       High 100%     High  98%     Med   61%     High  84%
KAND       High 100%     High  90%     Med   62%     Med   79%

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...JPT
SHORT TERM...WJM
LONG TERM...DEO
AVIATION...JPT

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
417 AM EDT Sun Jun 4 2017

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-050900-
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-
417 AM EDT Sun Jun 4 2017

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

.DAY ONE...Today and Tonight.

Scattered to numerous thunderstorms will develop around the region
this afternoon and evening. Any thunderstorms that develop will
produce cloud-to-ground lightning strikes, locally heavy rainfall,
and briefly gusty winds. A few thunderstorms may become severe and
produce damaging wind gusts and quarter-sized hail. Any thunderstorms
repeatedly affecting the same location could also cause localized
flash flooding. Some of this activity may continue through the
overnight hours.

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

..Monday...Heavy rain with flooding possible. Thunderstorms will
become quite numerous again on Monday and Monday night. A few of
these thunderstorms could become severe, but the bigger threat will
be localized flash flooding from any repeated heavy rain that may
fall on saturated ground.
..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...

Spotters are asked to relay any reports of damaging winds, large
hail, or flash flooding to our office.

HG

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
130 PM EDT SUN JUN 4 2017

SCZ003-005>007-010-041800-
Greater Pickens SC-Anderson SC-Greenville Mountains SC-
Spartanburg SC-Greater Greenville SC-
130 PM EDT SUN JUN 4 2017

...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN GREENVILLE...
NORTHWESTERN SPARTANBURG...NORTH CENTRAL ANDERSON AND EAST CENTRAL
PICKENS COUNTIES UNTIL 200 PM EDT...

At 130 PM EDT, Doppler radar was tracking a strong thunderstorm near
Easley, moving northeast at 30 mph.

Locations to be impacted include...
Greenville Downtown, Easley, Greenville Eastside, West Greenville,
Greer, Taylors, Berea, Welcome, Powdersville and Travelers Rest.

Nickel size hail will be possible in these areas.

LAT...LON 3472 8255 3489 8266 3517 8216 3493 8200
TIME...MOT...LOC 1730Z 240DEG 26KT 3485 8253

WJM

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
204 PM EDT SUN JUN 4 2017

NCZ508-510-SCZ003-007-008-041845-
Greater Rutherford NC-Eastern Polk NC-Cherokee SC-
Greenville Mountains SC-Spartanburg SC-
204 PM EDT SUN JUN 4 2017

...A STRONG THUNDERSTORM WILL IMPACT SOUTH CENTRAL RUTHERFORD...
SOUTHEASTERN POLK...NORTHEASTERN GREENVILLE...NORTHERN SPARTANBURG
AND NORTHWESTERN CHEROKEE COUNTIES UNTIL 245 PM EDT...

At 204 PM EDT, Doppler radar was tracking a strong thunderstorm 12
miles south of Columbus, or near Campobello, moving northeast at 40
mph.

Locations to be impacted include...
Rutherfordton, Spartanburg, Boiling Springs SC, Duncan, Lyman,
Landrum, Cowpens, Wellford, Inman and Mayo.

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

LAT...LON 3496 8222 3506 8222 3505 8227 3510 8230
      3536 8197 3501 8174 3488 8218
TIME...MOT...LOC 1804Z 239DEG 35KT 3507 8217

WJM

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
254 PM EDT SUN JUN 4 2017

SCZ006-007-012-042000-
Laurens SC-Spartanburg SC-Greater Greenville SC-
254 PM EDT SUN JUN 4 2017

...A STRONG THUNDERSTORM WITH INTENSE LIGHTNING WILL IMPACT
NORTHWESTERN LAURENS...SOUTHEASTERN GREENVILLE AND SOUTHWESTERN
SPARTANBURG COUNTIES UNTIL 400 PM EDT...

At 254 PM EDT, Doppler radar was tracking a strong thunderstorm with
intense lightning 16 miles northwest of Laurens, or 6 miles southwest
of Fountain Inn, moving northeast at 20 mph.

Locations to be impacted include...
Spartanburg, Mauldin, Simpsonville, Five Forks, Fountain Inn,
Woodruff, Roebuck, Gray Court, Reidville and Moore.

In addition to intense lightning, 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...

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. Do not drive across
flooded roads.

Frequent lightning is occurring with this storm. If outdoors, try to
get indoors or into a hard topped vehicle. Otherwise, stay away from
open areas and isolated high objects such as trees. When indoors,
stay away from windows and doors and avoid using wired electronic
devices. Do not take a shower or bath. Try to unplug unnecessary
appliances before the storm approaches.

&&

LAT...LON 3469 8244 3499 8202 3470 8182 3463 8184
      3446 8230
TIME...MOT...LOC 1854Z 237DEG 19KT 3463 8227

TDP

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
332 PM EDT SUN JUN 4 2017

NCZ035-036-042015-
Iredell NC-Alexander NC-
332 PM EDT SUN JUN 4 2017

...A STRONG THUNDERSTORM WILL IMPACT ALEXANDER AND NORTHERN IREDELL
COUNTIES UNTIL 415 PM EDT...

At 331 PM EDT, Doppler radar was tracking a strong thunderstorm near
Taylorsville, moving northeast at 20 mph.

Locations to be impacted include...
Taylorsville, Stony Point, Harmony, Love Valley, Lake Hickory,
Hiddenite, Olin, Millersville, Ellendale and Vashti.

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...

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. Do not drive across
flooded roads.

&&

LAT...LON 3605 8083 3594 8074 3579 8113 3583 8114
      3582 8120 3581 8122 3581 8124 3591 8131
      3604 8112 3603 8107 3606 8098
TIME...MOT...LOC 1931Z 237DEG 19KT 3588 8118

TDP