North Carolina, 2018

Flash Flood in North Carolina, May 31, 2018

May 31, 2018 · NWS GSP · 1 event in 1 county or zone

Scattered to numerous thunderstorms developed over western North Carolina during the afternoon and evening. Heavy rain from a storm falling over ground that was already saturated from more than two weeks of occasional heavy rainfall resulted in flash flooding across western Caldwell County.

Where it happened

Every event with a place to put it. Tap one for its entry below.

  • Tornadoes
  • Tropical storms and surge
  • Floods
  • Wind
  • Hail
  • Winter weather
  • Heat and drought
  • Cold
  • Fire, smoke and dust
  • Marine and coastal
  • Other

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The toll

Deaths
0
Injuries
0
Property damage
$5,000
Crop damage
None recorded
Events
1

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS GSP wrote it up.

Scattered to numerous thunderstorms developed over western North Carolina during the afternoon and evening. Heavy rain from a storm falling over ground that was already saturated from more than two weeks of occasional heavy rainfall resulted in flash flooding across western Caldwell County.

What forecasters said that day

The local office's own words before the first event, 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 the first event at May 31, 1:51 PM EST, 2 hours 39 minutes earlier.

Area forecast discussion, May 31, 1:51 PM EST, 2 hours 39 minutes before
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
251 PM EDT Thu May 31 2018

.SYNOPSIS...
A moist airmass will persist into Friday, with a couple of
rounds of thunderstorms crossing the region from the west in the
afternoon and evening. Slightly drier air will work in from the west
on Saturday, but with a brief return of moisture by late weekend.
Better drying will arrive behind a passing cold front in the early
to middle part of next week.

&&

.NEAR TERM /THROUGH FRIDAY/...
FLASH FLOOD WATCH FOR THE MOUNTAINS AND NC FOOTHILLS REMAINS IN
EFFECT THROUGH TONIGHT

As of 2pm EDT Thursday:  Round of showers and thunderstorms
currently underway with precipitation over much of Western North
Carolina , Northeast GA, and the foothills.  Showers will continue
into the evening, moving southeastward across the area.  Current
activity is related to upper wave cross the region with some
dynamical forcing.  Precipitable water values are down several
tenths of an inch from recent days, but with this upper support,
some heavy rain showers are still possible.  This wave is reinforced
by a second wave on Friday.  By Friday afternoon, a surface front
related to these upper waves will be come better defined and will
begin moving across the CWA. Surface front and better upper wave
will increase the strength of the wind profile and provide better
dynamical support for showers and thunderstorms Friday afternoon.
Friday showers; however, will be faster moving and will leave behind
less precipitation that what we will see today.  With some
improvement in the flooding conditions expected through Friday
morning, a Flash Flood Watch for Friday afternoon/evening does not
seem justified at this point.  However, it might be considered if
enough areas get appreciable rainfall this afternoon.  The Flash
Flood watch for this afternoon/tonight still looks good, but has
been trimmed 6 hours at the end as shower activity will decline
considerably by early Friday morning.

With some upper support on Friday, both shear and instability
increase, and chances for severe weather go up a notch with the
Friday storms.  Deep layer shear improves to 15kt, with CAPE to 1500
j/kg.  Shear is still too weak for much of a tornado threat, but
chances for severe outflows and some hail exist.  Any strong winds
from storm outflows could cause numerous tree falls as tree roots
have been weakened from recent rains. Following the round of thunder
on Friday, the passage of the front will bring dewpoints and chances
for precipitation down considerably.  Dewpoints decline 4 degrees by
Friday night. Temperatures will remain generally warm and humid
through Friday, however.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
As of 225 pm Thursday: The transition to a less tropical, more
typical late spring/early summer warm/humid regime will be completed
during the short term. Nevertheless, the pattern will remain quite
active, with a series of short wave troughs and attendant surface
features providing a focus for at least scattered diurnal convective
activity Sat and Sunday. Meanwhile, westerly deep layer flow will
allow for some modified elevated mixed layer air to filter into the
region, with mid-level lapse rates of 6.5-7 C/km progged through the
weekend. This will result in substantial sbCAPE each day, with
maximum afternoon values likely reaching at least 2500 J/kg. Thus,
while there may be less overall coverage of convection, especially
on Saturday, there will be higher potential for strong to severe
updrafts. This will most likely be in the form of pulse storms on
Saturday, when the deep layer shear will remain relatively weak, but
with more of a multicellular (if not something even more organized)
threat on Sunday, as deep layer shear increases to 30 to 40 kts
southeast of a robust short wave trough/upper low moving across the
Great Lakes. Although antecedent hydrologic conditions should
continue to gradually improve, a localized flash flood threat will
continue along the Blue Ridge into the weekend.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
As of 210 PM Thursday: Much drier air will filter into the region
behind a cold front Monday morning. The GFS is more robust with the
deep 500mb low moving ESE from the Great Lakes on Monday. The EC has
this feature more north and weaker. Both models take this low across
PA and New Jersey Tuesday and Tuesday night and enough shortwave
energy should affect the NC Mountains and somewhat less effects for
the foothills and piedmont. Certainly needs slight to low chance
POPs as it passes. Drier air again returns after the low moves off
the East Coast. A weak backdoor cold front drops down Wednesday or
Thursday but currently not expected to have much affect on our
weather. Going with a dry forecast Wednesday and Thursday.
Will need to watch the weak low over the NE Gulf and how it
influences our weather mid to late week. Temperatures will be near
or even a little below normal through the extended.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
At KCLT and elsewhere:  Generally low cloud decks have kept many
stations at MVFR today, with some possible improvement as the
afternoon progresses. Thunderstorms this afternoon will move across
the area from the northwest to southeast through 2z.  Storms will be
scattered, but some stations will have heavy rain, thunder, and
reduced visibility and ceilings as temporary conditions at times.
Included some fog overnight at KAVL, but most stations are not
expected to have problems as boundary layer moisture is gradually
declining.  Another round of thunderstorms is possible Friday
afternoon which will begin to affect TAF sites around 18Z.  These
storms will be occurring along and ahead of a front that will also
veer surface winds to be more southwesterly to westerly on Friday.

Outlook: Slightly drier air will filter into the area for the end of
the work week. However, scattered afternoon/evening showers and
thunderstorms, along with possible morning fog at a few locations
and/or low cigs are possible each day through early next week.

Confidence Table...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       High  93%     High 100%     High 100%     High 100%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High 100%     High 100%     High  83%     High 100%
KHKY       High  92%     High 100%     High  87%     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...Flash Flood Watch through Friday morning for GAZ010-017.
NC...Flash Flood Watch through Friday morning for NCZ033-048>053-
     058-059-062>065-501>510.
SC...Flash Flood Watch through Friday morning for SCZ001>003.

&&

SYNOPSIS...DEO
NEAR TERM...WJM
SHORT TERM...JDL
LONG TERM...DEO
AVIATION...WJM
Hazardous weather outlook, May 31, 2:53 PM EST, 1 hour 37 minutes before
Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
353 PM EDT Thu May 31 2018

GAZ018-026-028-029-NCZ035>037-056-057-068>072-082-SCZ004>014-019-
012000-
Stephens-Franklin-Hart-Elbert-Alexander-Iredell-Davie-Catawba-Rowan-
Cleveland-Lincoln-Gaston-Mecklenburg-Cabarrus-Union-Greater Oconee-
Greater Pickens-Greater Greenville-Spartanburg-Cherokee-York-
Anderson-Abbeville-Laurens-Chester-Greenwood-
353 PM EDT Thu May 31 2018

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

.DAY ONE...This Afternoon and Tonight.

Scattered to numerous thunderstorms will continue across much of the
area through this evening. A few of the storms will be capable of
producing severe weather in the form of damaging downburst winds and
large hail. Otherwise, torrential rainfall and frequent cloud to
ground lightning will be possible with any storm.

.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...

None.

GAZ010-017-NCZ033-048>053-058-059-062>065-501>510-SCZ001>003-012000-
Rabun-Habersham-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-
353 PM EDT Thu May 31 2018

...FLASH FLOOD WATCH IN EFFECT UNTIL 2 AM EDT FRIDAY...

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

.DAY ONE...This Afternoon and Tonight.

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

   Flash Flood Watch.

Scattered to numerous thunderstorms will continue across much of the
mountains and foothills through this evening. In addition to the
continued threat of localized flash flooding, a few of the storms
will be capable of producing severe weather in the form of damaging
downburst winds and large hail. Frequent cloud to ground lightning
will be possible with any storm.

.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...

None.

Lane

In the hours before

Special weather statement, May 31, 3:35 PM EST, 55 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
435 PM EDT THU MAY 31 2018

NCZ509-SCZ002-003-006-007-312115-
Polk Mountains NC-Pickens Mountains SC-Greenville Mountains SC-
Spartanburg SC-Greater Greenville SC-
435 PM EDT THU MAY 31 2018

...STRONG THUNDERSTORMS WITH INTENSE LIGHTNING WILL IMPACT
GREENVILLE...NORTHWESTERN SPARTANBURG AND NORTHEASTERN PICKENS
COUNTIES UNTIL 515 PM EDT...

At 435 PM EDT, Doppler radar indicated strong thunderstorms with
intense lightning along a line extending from 12 miles southwest of
Columbus to 9 miles northwest of Greenville Downtown, and moving
southeast at 25 mph.

Locations to be impacted include...
Greenville Downtown, Greenville Eastside, Greer, Mauldin, Taylors,
Five Forks, Travelers Rest, Duncan, Lyman and Landrum.

In addition to intense lightning, wind gusts up to 50 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.

Frequent lightning is occurring with these storms. 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 storms approach.

&&

LAT...LON 3492 8252 3497 8254 3496 8257 3497 8259
      3513 8262 3517 8251 3516 8250 3518 8248
      3518 8246 3516 8246 3517 8244 3520 8242
      3521 8238 3519 8238 3518 8237 3522 8235
      3515 8198 3469 8219 3470 8220
TIME...MOT...LOC 2035Z 297DEG 23KT 3509 8229 3497 8248

MOORE
Special weather statement, May 31, 3:47 PM EST, 43 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
447 PM EDT THU MAY 31 2018

SCZ006-010-312145-
Anderson SC-Greater Greenville SC-
447 PM EDT THU MAY 31 2018

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN GREENVILLE AND
CENTRAL ANDERSON COUNTIES UNTIL 545 PM EDT...

At 447 PM EDT, Doppler radar was tracking a strong thunderstorm 8
miles east of Anderson, or near Belton, moving southeast at 10 mph.

Locations to be impacted include...
Anderson, Homeland Park, Belton, Williamston, Northlake, Honea Path,
West Pelzer, Anderson Airport, Sandy Springs and Princeton.

Wind gusts up to 45 mph and half inch 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.

&&

LAT...LON 3451 8281 3462 8274 3466 8251 3459 8224
      3453 8224 3437 8249
TIME...MOT...LOC 2047Z 300DEG 9KT 3455 8250

MOORE
Special weather statement, May 31, 4:18 PM EST, 12 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
518 PM EDT THU MAY 31 2018

NCZ036-057-070>072-SCZ009-312215-
Rowan NC-Gaston NC-Iredell NC-Mecklenburg NC-Cabarrus NC-York SC-
518 PM EDT THU MAY 31 2018

...A CLUSTER OF THUNDERSTORMS WILL IMPACT WESTERN CABARRUS...
SOUTHEASTERN IREDELL...MECKLENBURG...SOUTHERN ROWAN...CENTRAL GASTON
AND NORTHEASTERN YORK COUNTIES UNTIL 615 PM EDT...

At 518 PM EDT, Doppler radar indicated the leading edge of a cluster
of thunderstorms along a line extending from 4 miles northwest of
Kannapolis to 6 miles southwest of Huntersville to near Gastonia, and
moving east at 15 mph.

Locations to be impacted include...
Gastonia, Uptown Charlotte, Huntersville, Kannapolis, Downtown
Concord, Central Charlotte, Northeast Charlotte, Southwest Charlotte,
East Charlotte and Northwest Charlotte.

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

LAT...LON 3527 8063 3504 8105 3528 8132 3541 8103
      3540 8096 3547 8095 3561 8075 3557 8028
TIME...MOT...LOC 2118Z 284DEG 13KT 3553 8069 3534 8092 3526 8120

MOORE
Local storm report, May 31, 4:20 PM EST, 10 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
520 PM EDT THU MAY 31 2018

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

0415 PM     TSTM WND DMG     1 SE CENTRAL            34.71N 82.76W
05/31/2018                   PICKENS            SC   LAW ENFORCEMENT

            SCHP REPORTED A TREE DOWN AT OLD PENDLETON RD AND
            EIGHTEEN MILE RD

&&
Local storm report, May 31, 4:20 PM EST, 10 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
520 PM EDT THU MAY 31 2018

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

0450 PM     TSTM WND DMG     5 NNW TAYLORS           34.99N 82.35W
05/31/2018                   GREENVILLE         SC   PUBLIC

            PUBLIC REPORTED A TREE DOWN ON SANDY FLAT RD N OF
            TAYLORS.

&&
Local storm report, May 31, 4:24 PM EST, 6 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
524 PM EDT THU MAY 31 2018

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

0450 PM     TSTM WND DMG     1 E TRAVELERS REST      34.97N 82.41W
05/31/2018                   GREENVILLE         SC   LAW ENFORCEMENT

            SCHP REPORTED A TREE DOWN ON HAWKINS RD AT BRIDWELL WAY.

0420 PM     TSTM WND DMG     6 ENE PENDLETON         34.67N 82.69W
05/31/2018                   ANDERSON           SC   LAW ENFORCEMENT

            SCHP REPORTED A TREE DOWN AT BISHOP BRANCH RD AND
            LIBERTY HIGHWAY

&&

LEC

The radar

The Greer radar (KGSP), 131 km away, was scanning. The volume nearest the first event began at 21:29 UTC.

Open the radar archive at this moment

Event by event

1 flash flood. Local standard time, as filed.

Flash Flood, Caldwell

When
May 31, 4:30 PM EST to 6:30 PM EST
Where
Caldwell County, 0.49 mi N of Edgemont to 0.87 mi ENE of Collettsville
Cause
Heavy Rain
Property damage
$5,000
Reported by
911 Call Center
Coordinates
36.007, -81.771

County comms reported flash flooding developed along portions of Wilson Creek and near the headwaters of the Johns River after around 2 inches of rain fell in a short period of time on already saturated soils. Multiple roads were reported as flooded and closed throughout the area.

What these are

Flash Flood
Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in North Carolina in 2018Every state in 2018This day in weather historyWarnings in North Carolina, May 2018

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 760183.