Alert archive / North Carolina / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 137, NWS Raleigh, NC

December 11, 20215 counties in North Carolina

NWS Raleigh, NC issued this severe thunderstorm warning at Dec 11, 2021, 6:30 PM EST for 5 counties in 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: Dec 11, 2021, 6:30 PM EST (23:30 UTC)
Expired: Dec 11, 2021, 7:15 PM EST
In force: 45 min
Issued by: NWS Raleigh, NC
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Alamance County, NC, Chatham County, NC, Guilford County, NC, Orange County, NC, Randolph County, NC

The radar

The Raleigh/Durham radar (KRAX), 73 km from the middle of the area, began a volume at 23:32 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, 11.5 hours before the alert went out and 63 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 481 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: 284 m²/s²
0-3 km storm-relative helicity: 258 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

697 
WUUS52 KRAH 112330
SVRRAH
NCC001-037-081-135-151-120015-
/O.NEW.KRAH.SV.W.0137.211211T2330Z-211212T0015Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Raleigh NC
630 PM EST Sat Dec 11 2021

The National Weather Service in Raleigh has issued a

* Severe Thunderstorm Warning for...
  Southern Alamance County in central North Carolina...
  Orange County in central North Carolina...
  Northeastern Randolph County in central North Carolina...
  Southeastern Guilford County in central North Carolina...
  Northwestern Chatham County in central North Carolina...

* Until 715 PM EST.

* At 630 PM EST, a severe thunderstorm was located 11 miles north of
  Siler City, moving east at 40 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees.

* Locations impacted include...
  Chapel Hill, Burlington, Graham, Hillsborough, Carrboro, Mebane,
  Liberty, Swepsonville, Alamance and Efland.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Straight line winds can blow down trees, power lines, and damage
mobile homes and other buildings. Seek shelter in a sturdy structure
until the storm has passed. Stay away from windows as flying debris
generated by damaging winds can be deadly.

&&

LAT...LON 3612 7897 3586 7902 3586 7901 3584 7902
      3582 7952 3576 7967 3604 7965
TIME...MOT...LOC 2330Z 255DEG 33KT 3590 7945 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

CA

1 follow-up statement

982 
WWUS52 KRAH 120010
SVSRAH

Severe Weather Statement
National Weather Service Raleigh NC
710 PM EST Sat Dec 11 2021

NCC001-037-081-135-151-120020-
/O.EXP.KRAH.SV.W.0137.000000T0000Z-211212T0015Z/
Alamance NC-Orange NC-Randolph NC-Guilford NC-Chatham NC-
710 PM EST Sat Dec 11 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN ALAMANCE...ORANGE...
NORTHEASTERN RANDOLPH...SOUTHEASTERN GUILFORD AND NORTHWESTERN
CHATHAM COUNTIES WILL EXPIRE AT 715 PM EST...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning will
be allowed to expire.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Raleigh.

LAT...LON 3612 7897 3586 7902 3586 7901 3584 7902
      3582 7952 3576 7967 3604 7965
TIME...MOT...LOC 0010Z 255DEG 33KT 3599 7904 

$$

Green

The office that day

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

Issued	Product	Office	Counties	Lasted
Dec 11, 3:58 PM EST	Special Weather Statement	RAH	Forsyth	47 min
Dec 11, 4:36 PM EST	Special Weather Statement	RAH	Davidson, Randolph	39 min
Dec 11, 4:52 PM EST	Special Weather Statement	RAH	Forsyth, Guilford	53 min
Dec 11, 5:19 PM EST	Special Weather Statement	RAH	Alamance, Davidson, Guilford, Randolph	56 min
Dec 11, 5:24 PM EST	Special Weather Statement	RAH	Montgomery, Stanly	36 min
Dec 11, 5:27 PM EST	Special Weather Statement	RAH	Montgomery, Stanly	33 min
Dec 11, 5:54 PM EST	Severe Thunderstorm Warning	RAH	Davidson, Guilford, Randolph	36 min
Dec 11, 5:56 PM EST	Special Weather Statement	RAH	Anson, Montgomery, Richmond, Stanly	34 min
Dec 11, 6:05 PM EST	Severe Thunderstorm Warning	RAH	Alamance, Guilford	40 min
Dec 11, 6:13 PM EST	Severe Thunderstorm Warning	RAH	Anson, Chatham, Lee, Montgomery, Moore, Randolph and 1 more	47 min
Dec 11, 6:15 PM EST	Special Weather Statement	RAH	Granville, Person, Vance	45 min
Dec 11, 6:44 PM EST	Severe Thunderstorm Warning	RAH	Alamance, Orange	46 min
Dec 11, 6:59 PM EST	Special Weather Statement	RAH	Franklin, Granville, Vance, Warren	61 min

Nearby

Severe Thunderstorm Warnings in North Carolina, 2021 Every severe thunderstorm warning in 2021

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.