Alert archive / North Carolina / Areal Flood Advisories in 2018

Areal Flood Advisory 252, NWS Greenville-Spartanburg, SC

August 20, 2018Caldwell County, North Carolina

NWS Greenville-Spartanburg, SC issued this areal flood advisory at Aug 20, 2018, 7:03 PM EDT for Caldwell County, North Carolina. It was in force for 117 min.

The area

The counties it named.

The facts

Issued
Aug 20, 2018, 7:03 PM EDT (23:03 UTC)
Expired
Aug 20, 2018, 9:00 PM EDT
In force
117 min
Issued by
NWS Greenville-Spartanburg, SC
Area
Storm-based polygon

County Caldwell County, NC

The radar

The Greer radar (KGSP), 134 km from the middle of the area, began a volume at 23:05 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 12:00Z, 11.1 hours before the alert went out and 149 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 12:00Z on 2018-08-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 430 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 12:00Z on 2018-08-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 32 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
430 J/kg
Mixed-layer CIN
-11 J/kg
Mixed-layer LCL
516 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
32 m²/s²
0-3 km storm-relative helicity
81 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this areal flood advisory 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 areal flood advisory went out at Aug 20, 5:17 PM EDT, 1 hour 46 minutes earlier.

Area forecast discussion, Aug 20, 5:17 PM EDT, 1 hour 46 minutes before
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Hazardous weather outlook, Aug 20, 4:08 PM EDT, 2 hours 55 minutes before
Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
408 PM EDT Mon Aug 20 2018

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-212015-
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-
408 PM EDT Mon Aug 20 2018

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

.DAY ONE...Tonight.

Scattered to numerous thunderstorms will continue into the evening
across the western Carolinas and northeast Georgia. The greatest
threat will be frequent cloud to ground lightning. The storms may
produce high rainfall rates that could lead to isolated urban, low
lying, and small stream flooding. The flooding threat will be highest
over the foothills and Piedmont of North Carolina. Additionally, a
few storms could become severe and produce large hail and damaging
wind gusts.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

On Tuesday, a robust cold front will approach the forecast area from
the west and help to generate numerous thunderstorms. Some of these
storms could become severe and produce large hail and damaging wind
gusts. Isolated urban and small stream flooding is also a threat
with these storms. The flooding threat will be greatest over the
higher terrain.

.SPOTTER INFORMATION STATEMENT...

None.

In the hours before

Special weather statement, Aug 20, 4:57 PM EDT, 2 hours 6 minutes before
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      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
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        The site you requested is temporarily down for maintenance or an unexpected outage.
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        Please try again in a few minutes.
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        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
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Special weather statement, Aug 20, 6:36 PM EDT, 27 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
636 PM EDT MON AUG 20 2018

NCZ501-502-202300-
Caldwell Mountains NC-Greater Caldwell NC-
636 PM EDT MON AUG 20 2018

...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN CALDWELL COUNTY
UNTIL 700 PM EDT...

At 635 PM EDT, Doppler radar was tracking a strong thunderstorm 10
miles west of Boomer, or near Elkville, moving northeast at 15 mph.

Locations to be impacted include...
Kings Creek.

Wind gusts up to 50 mph and pea size hail will be possible in these
areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Gusty winds can blow down trees that are dead, or that have weakened
root systems. Outdoor furniture and similar items can be tossed
around if not anchored. Seek shelter indoors.

&&

LAT...LON 3609 8147 3609 8145 3607 8144 3607 8141
      3605 8139 3604 8139 3604 8137 3600 8133
      3598 8133 3594 8142 3603 8156 3610 8151
      3610 8150
TIME...MOT...LOC 2235Z 223DEG 12KT 3603 8142

LANE
Special weather statement, Aug 20, 6:37 PM EDT, 26 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
637 PM EDT MON AUG 20 2018

NCZ053-202300-
Buncombe NC-
637 PM EDT MON AUG 20 2018

...A STRONG THUNDERSTORM WILL IMPACT SOUTH CENTRAL BUNCOMBE COUNTY
UNTIL 700 PM EDT...

At 637 PM EDT, Doppler radar was tracking a strong thunderstorm 9
miles north of Hendersonville, or near Arden, moving northeast at 20
mph.

Locations to be impacted include...
Fairview In Buncombe County, Arden and B.R. Parkway-Nc Arboretum To
East Asheville.

Wind gusts up to 50 mph and pea size hail will be possible in these
areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Gusty winds can blow down trees that are dead, or that have weakened
root systems. Outdoor furniture and similar items can be tossed
around if not anchored. Seek shelter indoors.

&&

LAT...LON 3551 8235 3547 8240 3547 8242 3546 8243
      3545 8247 3545 8252 3557 8249
TIME...MOT...LOC 2237Z 212DEG 16KT 3546 8248

LANE

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 19, 8:08 PM EDTSpecial Weather StatementGSPRowan37 min
Aug 19, 8:14 PM EDTSpecial Weather StatementGSPLincoln31 min
Aug 19, 8:45 PM EDTSpecial Weather StatementGSPCabarrus30 min
Aug 20, 4:14 AM EDTAreal Flood AdvisoryGSPCabarrus, Iredell, Rowan2 hr
Aug 20, 6:12 AM EDTAreal Flood AdvisoryGSPCabarrus, Iredell, Rowan2 hr
Aug 20, 4:57 PM EDTSpecial Weather StatementGSPBuncombe18 min
Aug 20, 6:36 PM EDTSpecial Weather StatementGSPCaldwell24 min
Aug 20, 6:37 PM EDTSpecial Weather StatementGSPBuncombe23 min
Aug 20, 7:48 PM EDTSpecial Weather StatementGSPAlexander42 min

Nearby

Areal Flood Advisories in North Carolina, 2018Every areal flood advisory in 2018

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.