Alert archive / North Carolina / Special Weather Statements in 2017

Special Weather Statement, NWS Greenville-Spartanburg, SC

August 4, 2017Iredell County, North Carolina

NWS Greenville-Spartanburg, SC issued this special weather statement at Aug 4, 2017, 8:45 PM EDT for Iredell County, North Carolina. It was in force for 45 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 4, 2017, 8:45 PM EDT (00:45 UTC)
Expired
Aug 4, 2017, 9:30 PM EDT
In force
45 min
Issued by
NWS Greenville-Spartanburg, SC

County Iredell County, NC

The radar

The Greer radar (KGSP), 149 km from the middle of the area, began a volume at 00:46 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Greensboro/Hi Pt, NC (KGSO), launched 00:00Z, 0.8 hours before the alert went out and 100 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Greensboro/Hi Pt, NC at 00:00Z on 2017-08-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 263 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Greensboro/Hi Pt, NC at 00:00Z on 2017-08-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 25 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
263 J/kg
Mixed-layer CIN
-9 J/kg
Mixed-layer LCL
1547 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
25 m²/s²
0-3 km storm-relative helicity
44 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.8

Open this sounding in Storm Lab

The text

As transmitted.

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What forecasters said that day

The local office's own words before this special weather statement went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Greenville-Spartanburg, SC wrote its last area forecast discussion before this special weather statement went out at Aug 4, 7:46 PM EDT, 59 minutes earlier.

Area forecast discussion, Aug 4, 7:46 PM EDT, 59 minutes before
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
746 PM EDT Fri Aug 4 2017

.SYNOPSIS...
A cold front will cross our area tonight and become stationary from
central Georgia to eastern North Carolina Saturday night. This front
moves north as a warm front Sunday and Sunday night as low pressure
passes from Texas to across the Ohio Valley.  The front will become
stationary again across our region for much of the week with deep
moisture and periods of heavy rain.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 730 pm: Radar is showing the pre-frontal convective line
solidifying as it moves east across the NC foothills early this
evening. LAPS sbCAPE analysis indicates that values have risen to
about 1000 to 1500 J/kg ahead of this line across the NC piedmont,
and various mesoscale models are now depicting solid 30 to 35 kt of
surface to 6 km bulk shear out over the I-77 corridor through the
evening. Additional isolated severe thunderstorms look likely as
this system moves east through late evening, with damaging wind
gusts being the primary threat across mainly the rest of the NC
foothills and the NC piedmont. Convection may also fill in a bit
across the southern tier, both in the pre-frontal line and across
the lower piedmont with activity moving northeast out of GA.

Anticipate the surface cold front, which is still west of the
mountains, to slowly move southeast across the mountains and
foothills through the overnight hours and then settle across the
lower piedmont through the day on Saturday. Drier air will gradually
start to filter in from the northwest, but lower stratus may develop
in the W to NW flow across the mountains overnight, and some stratus
could also develop in piedmont sections before the drying arrives.
Mins should be near to just above climo overnight.

Even though the boundary will settle near, or southeast of, our srn
tier on Saturday, the moisture gradient across the boundary will be
sufficiently broad such that positive buoyancy is progged to develop
from roughly the NC/SC border southward. Diurnal frontal convection
should primarily be focused south of our area, but a slight chance
is nevertheless warranted southeast of I-85. Meanwhile, instability
should be sufficient to fire some isolated cells across the southern
Blue Ridge, and slight chances will be carried across the southern
mtns as well as the southern NC and SC foothills. Max temps should
again fall just shy of climo.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of 215 PM Friday: An upper wave will cross the Central Plains and
into the Mid-MS Valley Saturday night thru Sunday, possibly being
enhanced by an MCS. This wave will then shear out within confluent
quasi-zonal flow over the OH Valley to the Mid-Atlantic Sunday night
thru Monday. At the sfc, a stalled front will lift back north as a
warm front, but will be fairly weak. Guidance has slowed down the
return of moisture atop the front thru the day on Sunday, so PoPs
were tweaked downward, especially across the northern half of the
CWFA. As for severe threat, guidance shows limited overlap of CAPE
and bulk shear. So threat should be low. A wavy front roughly
parallel to the upper level flow will set up across the Mid-South to
the OH Valley. Persistent SWLY flow atop the CWFA on the south side
of this boundary will provide plenty of moisture for convection on
Monday. So will have PoPs ramp up to high-end CHC to likely along
the west-facing slopes. Max temps will be near to slightly below
normal and mins near normal both days.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 155 PM Fri: Beginning Monday evening, the cold front drifts
south into our area from Tennessee then becomes nearly stationary
roughly from west to east across the deep south to the Carolinas.
The front remains this way through the remainder of the forecast.
Precipitable water values will be around 2 inches and at times above
that, especially from Wednesday through Friday. This prolonged
period of high Pwats with a stationary front to focus convection
will result in concerns for potential flooding which will increase
as the ground becomes saturated. A broad 500mb trough remains over
the East with shortwaves rotating SE from the upper Plains states to
our region then NE off the New England coast. This will periodically
enhance rainfall as surface low pressures move along the front over
our area. As a result of the thick cloud cover and periods of rain,
max temperatures are trending downward. Looks like Wednesday may be
the coolest as forecast highs from northeast Georgia to Charlotte
are in the lower 80s and this may be too high given the saturation
of the atmosphere. Overall max temperatures several degrees below
normal and Min temperatures near normal or even slightly above given
the thick clouds. There may also be periods of late night and early
morning fog to deal with as dew points and temperatures match
yielding 100% RH.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
At KCLT: Convection is organizing over the foothills and should
sweep east through the airfield vicinity mainly between 01Z and 03Z.
Expect west to northwest wind gusts to accompany the main line along
with brief restrictions to visibility and lower cigs. Showers may
linger into the early morning hours before drier air starts to
filter in from the NW. Some model profiles show lower stratus
developing behind the departing precipitation but just ahead of the
approaching cold front, and this is possible, but confidence is too
low to mention more than a SCT deck at MVFR levels at this point
during the early morning hours. Winds should toggle NW around
daybreak Saturday with fropa, with mainly NW flow and VFR conditions
through the day.

Elsewhere, the pre-frontal convective threat will impact mainly KHKY
through 02Z, with smaller chances at the Upstate TAF sites. TSRA
should depart east of KAVL quickly after issuance time, but isolated
activity along the immediate cold front remains possible through
late evening. Lower stratus in the moist W to NW flow will brings
restrictions to at least KAVL overnight into Saturday morning, while
drier air will start to filter into the foothills overnight through
Saturday. A few models hint at low stratus, but will hedge with
mainly SCT low clouds across the foothills overnight. Post fropa NW
flow will toggle back toward SW at the Upstate sites through
Saturday.

Outlook: The cold front will settle southeast of the terminal area
through Saturday night. Moisture will then steadily return over the
front back into the region Sunday through Monday. Unsettled
conditions will set up through at least the middle of the week as
the boundary remains nearby and moisture pools overhead as a series
of upper level waves pass by. Restrictions will be possible with any
showers or thunderstorms, and fog and low clouds will be possible
each morning around daybreak, mainly in the mtn valleys, but also in
areas that receive heavy rainfall the day before.

Confidence Table...

            23-05Z        05-11Z        11-17Z        17-18Z
KCLT       High 100%     High 100%     High  95%     High 100%
KGSP       High 100%     High 100%     High  95%     High 100%
KAVL       High 100%     High 100%     High  80%     High 100%
KHKY       High  94%     High 100%     Med   66%     High 100%
KGMU       High 100%     High 100%     High 100%     High 100%
KAND       High 100%     High 100%     High  83%     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...DEO
NEAR TERM...HG
SHORT TERM...ARK
LONG TERM...DEO
AVIATION...HG
Hazardous weather outlook, Aug 4, 7:53 PM EDT, 52 minutes before
Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
753 PM EDT Fri Aug 4 2017

GAZ010-017-018-026-028-029-NCZ033-048>053-058-059-062>065-501>510-
SCZ001>007-010>014-019-060000-
Rabun-Habersham-Stephens-Franklin-Hart-Elbert-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-Rutherford Mountains-Greater Rutherford-
Polk Mountains-Eastern Polk-Oconee Mountains-Pickens Mountains-
Greenville Mountains-Greater Oconee-Greater Pickens-
Greater Greenville-Spartanburg-Anderson-Abbeville-Laurens-Union-
Chester-Greenwood-
753 PM EDT Fri Aug 4 2017

This Hazardous Weather Outlook is for northeast Georgia, the
mountains and foothills of western North Carolina, and Upstate South
Carolina.

.DAY ONE...Tonight.

Scattered thunderstorms will move across the region through the late
evening hours. Any of these thunderstorms will produce cloud-to-
ground lightning and heavy rainfall. An isolated thunderstorm may
become severe, producing damaging wind gusts and hail up to around
one inch in diameter.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

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

.SPOTTER INFORMATION STATEMENT...

None.

NCZ035>037-056-057-068>072-082-SCZ008-009-060000-
Alexander-Iredell-Davie-Catawba-Rowan-Cleveland-Lincoln-Gaston-
Mecklenburg-Cabarrus-Union-Cherokee-York-
753 PM EDT Fri Aug 4 2017

This Hazardous Weather Outlook is for the piedmont of western North
Carolina and the eastern Upstate of South Carolina.

.DAY ONE...Tonight.

A line of thunderstorms will move east through the region this
evening. These thunderstorms will bring widespread cloud-to-ground
lightning strikes, very heavy rainfall, and gusty winds of 30 to 40
mph. A few of the thunderstorms may become severe, with winds in
excess of 60 mph being the main threat, and hail up to one inch in
diameter posing a secondary threat. Isolated flooding of poor
drainage and low-lying areas will be possible as well.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

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

.SPOTTER INFORMATION STATEMENT...

Spotters are asked to report any wind damage, large hail, or flooding
to the National Weather Service.

Gerapetritis

In the hours before

Local storm report, Aug 4, 7:49 PM EDT, 56 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
749 PM EDT FRI AUG 4 2017

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

0652 PM     TSTM WND DMG     SUGAR HILL              35.58N 82.05W
08/04/2017                   MCDOWELL           NC   FIRE DEPT/RESCUE

            FIRE DEPT REPORTED A TREE DOWN ON MONTFORD COVE RD AT
            SUGAR HILL RD. TIME ESTIMATED FROM RADAR.

&&

LEC
Special weather statement, Aug 4, 7:54 PM EDT, 51 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
754 PM EDT FRI AUG 4 2017

NCZ068-508-510-050045-
Greater Rutherford NC-Cleveland NC-Eastern Polk NC-
754 PM EDT FRI AUG 4 2017

...A STRONG THUNDERSTORM WITH INTENSE LIGHTNING WILL IMPACT
SOUTHEASTERN RUTHERFORD...SOUTHEASTERN POLK AND SOUTHWESTERN
CLEVELAND COUNTIES UNTIL 845 PM EDT...

At 754 PM EDT, Doppler radar was tracking a strong thunderstorm with
intense lightning over Rutherfordton, moving southeast at 20 mph.

Locations to be impacted include...
Forest City, Rutherfordton, Spindale, Boiling Springs NC, Ellenboro,
Lattimore, Mooresboro, Bostic, Kingstown and Polkville.

In addition to intense lightning, wind gusts up to 50 mph and pea
size hail 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.

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 3536 8151 3518 8173 3519 8199 3533 8213
      3546 8194
TIME...MOT...LOC 2354Z 311DEG 18KT 3535 8196

CDG
Special weather statement, Aug 4, 8:00 PM EDT, 45 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
800 PM EDT FRI AUG 4 2017

NCZ056-068-069-050045-
Cleveland NC-Lincoln NC-Catawba NC-
800 PM EDT FRI AUG 4 2017

...A STRONG THUNDERSTORM WITH INTENSE LIGHTNING WILL IMPACT
SOUTHWESTERN CATAWBA...WESTERN LINCOLN AND NORTH CENTRAL CLEVELAND
COUNTIES UNTIL 845 PM EDT...

At 800 PM EDT, Doppler radar was tracking a strong thunderstorm with
intense lightning 14 miles west of Lincolnton, or 5 miles north of
Belwood, moving east at 20 mph.

Locations to be impacted include...
Belwood, Cooksville, Crouse, Propst Crossroads, Startown and Vale.

In addition to intense lightning, wind gusts up to 45 mph and pea
size hail 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.

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 3541 8128 3541 8130 3546 8158 3556 8157
      3557 8153 3561 8151 3566 8146 3569 8125
TIME...MOT...LOC 0000Z 273DEG 16KT 3555 8149

CDG
Local storm report, Aug 4, 8:36 PM EDT, 9 minutes before
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Local storm report, Aug 4, 8:42 PM EDT, 3 minutes before
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Special weather statement, Aug 4, 8:45 PM EDT, 0 minutes before
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The office that day

Everything else NWS Greenville-Spartanburg, SC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 4, 8:00 PM EDTSpecial Weather StatementGSPLincoln45 min
Aug 4, 8:26 PM EDTSevere Thunderstorm WarningGSPGaston, Lincoln49 min
Aug 4, 9:14 PM EDTSpecial Weather StatementGSPCabarrus, Gaston, Mecklenburg61 min
Aug 4, 9:17 PM EDTSpecial Weather StatementGSPDavie, Rowan43 min
Aug 4, 9:56 PM EDTAreal Flood AdvisoryGSPGaston64 min
Aug 4, 10:19 PM EDTSpecial Weather StatementGSPCabarrus, Rowan41 min
Aug 4, 9:23 PM EDTSpecial Weather StatementGSPCherokee52 min
Aug 4, 9:26 PM EDTSpecial Weather StatementGSPCherokee, Spartanburg64 min
Aug 4, 9:31 PM EDTSpecial Weather StatementGSPGreenville, Pickens44 min
Aug 4, 10:03 PM EDTSpecial Weather StatementGSPYork57 min
Aug 4, 10:42 PM EDTSpecial Weather StatementGSPGreenville63 min
Aug 4, 11:33 PM EDTSpecial Weather StatementGSPGreenville42 min

Nearby

Special Weather Statements in North Carolina, 2017Every special weather statement in 2017

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.