Alert archive / North Carolina / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 141, NWS Raleigh, NC

August 6, 20204 counties in North Carolina

NWS Raleigh, NC issued this severe thunderstorm warning at Aug 6, 2020, 2:03 PM EDT for 4 counties in North Carolina. It was in force for 57 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Aug 6, 2020, 2:03 PM EDT (18:03 UTC)
Expired: Aug 6, 2020, 3:00 PM EDT
In force: 57 min
Issued by: NWS Raleigh, NC
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Durham County, NC, Franklin County, NC, Granville County, NC, Wake County, NC

The radar

The Raleigh/Durham radar (KRAX), 45 km from the middle of the area, began a volume at 18:05 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, 6.1 hours before the alert went out and 115 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 864 J/kg
Mixed-layer CIN: -18 J/kg
Mixed-layer LCL: 667 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 55 m²/s²
0-3 km storm-relative helicity: 86 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.8

Open this sounding in Storm Lab

What forecasters said that day

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

NWS Raleigh, NC wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 6, 1:40 PM EDT, 23 minutes earlier.

Area forecast discussion, Aug 6, 1:40 PM EDT, 23 minutes before

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Hazardous weather outlook, Aug 6, 5:25 AM EDT, 8 hours 38 minutes before

Hazardous Weather Outlook
National Weather Service Raleigh NC
525 AM EDT Thu Aug 6 2020

NCZ007>011-021>028-038>043-073>078-083>086-088-089-070930-
Person-Granville-Vance-Warren-Halifax-Forsyth-Guilford-Alamance-
Orange-Durham-Franklin-Nash-Edgecombe-Davidson-Randolph-Chatham-Wake-
Johnston-Wilson-Stanly-Montgomery-Moore-Lee-Harnett-Wayne-Anson-
Richmond-Scotland-Hoke-Cumberland-Sampson-
525 AM EDT Thu Aug 6 2020

This Hazardous Weather Outlook is for central North Carolina.

.DAY ONE...Today and tonight.

Patchy dense fog this morning will create visibility of 1/2 mile or
less at times.

Scattered to numerous thunderstorms will develop this afternoon, some
of which could be severe and generate heavy rain. Damaging wind
gusts and isolated flash flooding are possible near storms.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

Hazardous weather is not expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed.

In the hours before

Special weather statement, Aug 6, 1:05 PM EDT, 58 minutes before

Special Weather Statement
National Weather Service Raleigh NC
105 PM EDT Thu Aug 6 2020

NCZ089-061800-
Sampson NC-
105 PM EDT Thu Aug 6 2020

...SLOW-MOVING THUNDERSTORMS WILL AFFECT SOUTHEASTERN SAMPSON COUNTY
UNTIL 200 PM EDT...

At 103 PM EDT, Doppler radar was tracking a scattered, slow-moving
thunderstorms near Harrells, or 16 miles south of Clinton, moving
northeast at 5 to 10 mph.

Heavy rain of one to two inches and minor flooding will be possible
with thse storms.

Locations impacted include...
Harrells and Garland.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Locally heavy rain will quickly reduce visibility and result in
ponding of water on roadways, standing water in low lying areas, and
minor flooding of creeks, streams, and areas of poor drainage.
Drivers are urged to slow down and use extra caution to avoid
hydroplaning, especially in urban areas where prolonged heavy rain
can quickly lead to flooding.

&&

LAT...LON 3461 7831 3463 7832 3464 7831 3465 7832
      3467 7832 3470 7837 3473 7839 3475 7839
      3478 7843 3483 7847 3497 7815 3490 7815
      3474 7820 3471 7813 3472 7811 3471 7811
      3460 7829
TIME...MOT...LOC 1703Z 242DEG 7KT 3477 7828

26

Special weather statement, Aug 6, 1:43 PM EDT, 20 minutes before

Special Weather Statement
National Weather Service Raleigh NC
143 PM EDT Thu Aug 6 2020

NCZ008-025-041-061845-
Durham NC-Wake NC-Granville NC-
143 PM EDT Thu Aug 6 2020

...A STRONG THUNDERSTORM WILL AFFECT SOUTHERN GRANVILLE...NORTH
CENTRAL WAKE AND CENTRAL DURHAM COUNTIES UNTIL 245 PM EDT...

At 143 PM EDT, Doppler radar was tracking a strong thunderstorm near
Butner, or 7 miles northeast of Durham, moving east at 15 mph.

Wind gusts up to 40 mph will be possible with this storm.

Locations impacted include...
Durham, Creedmoor, Wake Forest, Butner, Falls Lake, Falls Lake State
Rec Area, Purnell, Gorman, Rollingview Marina and Lake Michie.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Seek shelter in a nearby building or vehicle. Wind gusts as high as
40 mph are capable of knocking down tree limbs and blowing around
trash cans, potted plants, lawn furniture and other light outdoor
objects.

&&

LAT...LON 3624 7851 3618 7851 3618 7850 3617 7850
      3608 7854 3602 7855 3598 7844 3600 7894
      3613 7896
TIME...MOT...LOC 1743Z 259DEG 13KT 3606 7886

23

The office that day

Everything else NWS Raleigh, NC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 5, 8:54 PM EDT	Special Weather Statement	RAH	Forsyth	36 min
Aug 5, 10:59 PM EDT	Special Weather Statement	RAH	Forsyth	91 min
Aug 5, 11:32 PM EDT	Areal Flood Advisory	RAH	Davidson, Forsyth	100 min
Aug 6, 12:02 AM EDT	Flash Flood Warning Considerable damage threat	RAH	Forsyth	86 min
Aug 6, 12:33 AM EDT	Special Weather Statement	RAH	Guilford	57 min
Aug 6, 2:27 AM EDT	Special Weather Statement	RAH	Alamance, Orange, Person	78 min
Aug 6, 3:12 AM EDT	Special Weather Statement	RAH	Granville, Orange, Person	63 min
Aug 6, 1:05 PM EDT	Special Weather Statement	RAH	Sampson	55 min
Aug 6, 1:43 PM EDT	Special Weather Statement	RAH	Durham	62 min
Aug 6, 3:05 PM EDT	Special Weather Statement	RAH	Harnett, Lee	55 min
Aug 6, 3:26 PM EDT	Special Weather Statement	RAH	Orange	34 min
Aug 6, 3:27 PM EDT	Special Weather Statement	RAH	Franklin, Nash, Wake	63 min
Aug 6, 3:42 PM EDT	Severe Thunderstorm Warning	RAH	Franklin, Johnston, Nash, Wake, Wilson	48 min
Aug 6, 4:13 PM EDT	Flash Flood Warning Considerable damage threat	RAH	Harnett	2 hr
Aug 6, 4:31 PM EDT	Special Weather Statement	RAH	Johnston	59 min
Aug 6, 4:45 PM EDT	Special Weather Statement	RAH	Montgomery	60 min
Aug 6, 4:56 PM EDT	Areal Flood Advisory	RAH	Franklin, Johnston, Nash, Wake, Wilson	3 hr
Aug 6, 5:43 PM EDT	Severe Thunderstorm Warning	RAH	Person	47 min
Aug 6, 6:03 PM EDT	Special Weather Statement	RAH	Forsyth, Guilford	57 min
Aug 6, 6:26 PM EDT	Flash Flood Warning Considerable damage threat	RAH	Forsyth	3 hr
Aug 6, 6:32 PM EDT	Severe Thunderstorm Warning	RAH	Forsyth, Guilford	43 min
Aug 6, 6:45 PM EDT	Flash Flood Warning Considerable damage threat	RAH	Guilford	8 hr
Aug 6, 7:03 PM EDT	Flash Flood Warning Considerable damage threat	RAH	Davidson	4 hr
Aug 6, 7:48 PM EDT	Special Weather Statement	RAH	Davidson, Guilford, Randolph	57 min

Nearby

Severe Thunderstorm Warnings in North Carolina, 2020 Every severe thunderstorm warning in 2020

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.