Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
744 PM EDT Sat Sep 1 2018

.SYNOPSIS...
A strong upper-level ridge will dominate the Southeast through the
middle of next week, resulting in above normal temperatures and
reduced precipitation chances outside of the mountains.

&&

.NEAR TERM /THROUGH SUNDAY/...
As of 730 PM: The best late day residual outflows are occurring
across the northwest piedmont of western North Carolina this evening
and high scattered to low end numerous coverage will be featured for
a couple of hours near I-77 and I-40. The latest HRRR still
diminishes coverage very quickly through 02Z in this region but it
does permit new outflow development across portions of the Upstate
through midnight. The general pattern should be gradually away from
outflow driven convection and more toward isolated to scattered
showers forming in the southeasterly upslope areas of the southern
Appalachians. In the upslope escarpment region, low end shower
chances will be retained all night, while activity will dissipate
elsewhere. Expect another round of mountain valley low stratus and
fog as well given the abundant low level moisture there.

The upper ridge will remain in place Sunday with a moist low level
easterly flow. Expect a downturn in convective coverage with the
ridge helping lower instability. However, there should be enough
moisture and instability for scattered coverage over the mountains
and isolated coverage elsewhere. Thickness values actually drop a
little Sunday despite the ridge. This with the potential for morning
clouds should keep highs a little lower than Saturday's readings.
Still, expect highs around 5 degrees above normal.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
As of 245 PM Sat: The East Coast ridge will approach peak intensity
during the short-range period, possibly topping out at 597dm
heading into Tuesday.  The impact of the ridge is significantly more
evident in the PoPs and total water content than it was yesterday,
with the much lower PoPs in the overnight forecast carried over
into today's guidance and PWs nearer to the 75th percentile (~1.5
inches) than the 90th percentile.  The 700-850 mb inversion is
progged to be a bit stronger on Tuesday as the ridge strengthens
over the Mid-Atlantic, translating to a stronger cap.  Furthermore,
the upslope-inducing easterly and southeasterly flow into the
region appears to be less influential on convective initiation
and coverage in recent guidance during the period.  Therefore,
the net effect will be negligible diurnal precip chances over the
Piedmont and only slight chances over the mountains.  We continue
to advertise a localized heavy rain threat with any storm that
develops due to very week steering flow and healthy PWs, but PWs
aren't high enough and these pulse cells should last long enough to
be overly concerned.  Ample subsidence-induced dry air is present
in the mid-levels so isolated strong downdrafts remain possible,
but this threat is also decreasing. If anything, the sudden lack of
rainfall over the past couple of weeks across much of the area may
be the greater concern for many.  Temperatures remain 2-4 degrees
above-normal which isn't too bad considering the strength of the
ridge, but humidity values will remain quite uncomfortable.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
As of 245 PM Sun: As mentioned above, the Eastern ConUS ridge will
peak in intensity Tuesday into Wednesday and then slowly breakdown
heading into next weekend in response to height falls over the
Northeast and Great Lakes regions.  As shortwave energy depicted
by an elongated vorticity axis drops south into the Mid-Atlantic,
an associated weak cold front will also drift south.

As the ridge breaks down, guidance becomes more bullish about
diurnally driven convective chances, increasing PoPs to high-end
chance (40-55%) across the mountains and introducing chance PoPs
across the Piedmont and Foothills beginning Wednesday but especially
Thursday through Saturday as the front approaches the area (but
remains to our north).  These increased chances are in response to
increasing laspe rates as the column aloft cools somewhat and the
persistent presence of weak easterly to southeasterly flow, which
will advect moisture, induce upslope forcing, and perhaps alllow
the seabreeze to work into the central Carolinas.  Total moisture
content will increase a bit as well late week so with continued weak
steering flow the localized heavy rain threat will increase into
the weekend as well.  Max temperatures change little despite the
pattern evolution, remaining 2-4 degrees above normal.  Guidance
wants to reduce dewpoints into the middle and upper 60s with
slight reductions in min temperature late week despite increasing
moisture. We shall see if this trend continues in future cycles.

The guidance is grumbling about increased activity over the
northern Gulf in association with tropical waves propagating
through the easterly flow to the south of the ridge as we head
into late week, but with the ridge decaying overhead the deepest
moisture at this time is pushed well west of our area.  During the
peak of the tropical season, upper-level ridges are our best
friends. Nevertheless, that moisture will take a circuitous route
around the ridge into the Mid-South and Ohio Valley and pool along
the front as it sags south.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
At KCLT and elsewhere: Outflow driven TSRA will be most likely to
impact KHKY through 02Z, with chances too low to mention at the
other sites. The Upstate outflows are moving away from KCLT, so no
mention is needed there for now, but close attention will have to be
paid to the outflow dropping southwest from the INT/GSO area that is
triggering new storms along and south of I-40 and near I-85 east of
Rowan County. If nothing else, these outflows may reinforce the ENE
to NE flow at KCLT later this evening. Anticipate the development of
low stratus and fog, most likely LIFR or worse, in the mountain
river valleys overnight. However, given the rainfall and ENE winds
along the I-40 area, MVFR to IFR stratus should form near KHKY, and
MVFR clouds could flirt with KCLT toward daybreak. Will keep KCLT
and the Upstate TAF sites VFR for now overnight. Redeveloping
cumulus is expected on Sunday and convective coverage may be a bit
less with the building ridge aloft. Expect ENE flow through the
period, except possibly turning SE at KAND on Sunday. Light winds at
KAVL will come up initially from the NW Sunday morning and then turn
SE during the afternoon. KAVL will see the best scattered
thunderstorm chances as well Sunday afternoon.

Outlook: Scattered diurnal showers and thunderstorms are expected
each afternoon Sunday through Tuesday. Areas of fog and low stratus
can also be expected each morning, primarily in the mtn valleys.

Confidence Table...

            23-05Z        05-11Z        11-17Z        17-18Z
KCLT       High 100%     High 100%     High 100%     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%     Med   72%     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

&&

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

&&

SYNOPSIS...JPT
NEAR TERM...HG
SHORT TERM...JMP
LONG TERM...JMP
AVIATION...HG

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
330 PM EDT Sat Sep 1 2018

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-021930-
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-
330 PM EDT Sat Sep 1 2018

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

.DAY ONE...This afternoon and tonight.

Isolated to scattered thunderstorms are expected through this
evening. Cloud-to-ground lightning, torrential rainfall, and strong
wind gusts are possible with any of these thunderstorms.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

JMP

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
711 PM EDT SAT SEP 1 2018

NCZ036-037-012345-
Davie NC-Iredell NC-
711 PM EDT SAT SEP 1 2018

...A STRONG THUNDERSTORM WITH INTENSE LIGHTNING WILL IMPACT
NORTHWESTERN DAVIE AND NORTHEASTERN IREDELL COUNTIES UNTIL 745 PM
EDT...

At 711 PM EDT, Doppler radar was tracking a strong thunderstorm with
intense lightning 8 miles northwest of Mocksville, or 4 miles east of
Harmony. This storm was nearly stationary.

Locations to be impacted include...
Harmony and Sheffield.

In addition to intense lightning, wind gusts up to 50 mph and pea
size hail will be possible in these areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3605 8062 3600 8055 3593 8061 3589 8069
      3596 8081 3605 8074
TIME...MOT...LOC 2311Z 117DEG 1KT 3596 8069

MOORE

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
713 PM EDT SAT SEP 1 2018

NCZ056-012345-
Catawba NC-
713 PM EDT SAT SEP 1 2018

...A STRONG THUNDERSTORM WILL IMPACT SOUTH CENTRAL CATAWBA COUNTY
UNTIL 745 PM EDT...

At 713 PM EDT, Doppler radar was tracking a strong thunderstorm near
Newton. This storm was nearly stationary.

Locations to be impacted include...
Newton, Conover, Maiden, St. Stephens and Startown.

Wind gusts up to 45 mph, pea size hail and very heavy rainfall rates
up to 2 inches per hour will be possible in these areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm may intensify, so be certain to monitor local radio and tv
stations, as well as local cable tv outlets for additional
information and possible warnings from the National Weather Service.

&&

LAT...LON 3565 8111 3557 8115 3555 8121 3556 8121
      3556 8123 3563 8135 3577 8124
TIME...MOT...LOC 2313Z 117DEG 1KT 3563 8122

MOORE

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
728 PM EDT SAT SEP 1 2018

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

0712 PM     TSTM WND DMG     4 E HARMONY             35.95N 80.69W
09/01/2018                   DAVIE              NC   TRAINED SPOTTER

            SPOTTER REPORTED DURING THE EVENT AS AT LEAST 2 OAK TREES
            FELL BEHIND HIS HOUSE WITH A 62 MPH GUST. THIS WAS
            FOLLOWED BY A BRIEF PERIOD OF PEA SIZED HAIL. THIS
            LOCATION IS JUST OFF EDWARDS ROAD...3 MILES SOUTHWEST OF
            SHEFFIELD.

&&

OUTLAW

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
746 PM EDT SAT SEP 1 2018

NCZ035-036-020030-
Iredell NC-Alexander NC-
746 PM EDT SAT SEP 1 2018

...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN ALEXANDER AND
NORTHERN IREDELL COUNTIES UNTIL 830 PM EDT...

At 745 PM EDT, Doppler radar was tracking a strong thunderstorm 10
miles north of Statesville, or 5 miles southeast of Love Valley.
This storm was nearly stationary. Several other strong thunderstorms
were located across Iredell and Alexander counties...all of which
were hardly moving at all.

Locations to be impacted include...
Statesville, Stony Point, Harmony, Love Valley, Hiddenite,
Turnersburg, Olin, Vashti, Union Grove and Scotts.

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.

&&

LAT...LON 3605 8085 3599 8070 3585 8071 3575 8074
      3578 8090 3587 8113 3603 8119 3603 8117
      3604 8113 3603 8107 3606 8098
TIME...MOT...LOC 2345Z 117DEG 1KT 3594 8092

MOORE

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
801 PM EDT SAT SEP 1 2018

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

0705 PM     TSTM WND DMG     2 W STATESVILLE         35.79N 80.92W
09/01/2018                   IREDELL            NC   911 CALL CENTER

            TREES AND A FEW POWER LINES DOWN ALONG FRONT STREET.

&&

OUTLAW

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
821 PM EDT SAT SEP 1 2018

NCZ035-036-056-020100-
Iredell NC-Alexander NC-Catawba NC-
821 PM EDT SAT SEP 1 2018

...A STRONG THUNDERSTORM WILL IMPACT NORTH CENTRAL CATAWBA...
ALEXANDER AND NORTHWESTERN IREDELL COUNTIES UNTIL 900 PM EDT...

At 820 PM EDT, Doppler radar was tracking a strong thunderstorm 8
miles northeast of Newton, or near Lookout Shoals Lake, moving north
at 5 mph. Another strong storm was located near Love Valley, also
moving slowly north at 5 mph.

Locations to be impacted include...
Taylorsville, Stony Point, Claremont, Love Valley, Lookout Shoals
Lake, Catawba, Conover, Lake Hickory, Hiddenite and Millersville.

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.

&&

LAT...LON 3605 8089 3568 8110 3574 8124 3603 8122
      3604 8119 3603 8117 3604 8114 3604 8111
      3603 8110 3603 8107 3606 8098 3606 8089
TIME...MOT...LOC 0020Z 199DEG 5KT 3577 8115

MOORE