Alert archive / North Carolina / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 273
The Storm Prediction Center issued this severe thunderstorm watch at May 10, 2011, 10:42 PM EDT for 19 counties in North Carolina; 7 counties in South Carolina; 8 counties in Tennessee. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- May 10, 2011, 10:42 PM EDT (02:42 UTC)
- Expired
- May 11, 2011, 3:00 AM EDT
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 34 counties
Alexander County, NC, Avery County, NC, Buncombe County, NC, Burke County, NC, Caldwell County, NC, Catawba County, NC, Cleveland County, NC, Gaston County, NC, Haywood County, NC, Henderson County, NC, Iredell County, NC, Lincoln County, NC, Madison County, NC, McDowell County, NC, Mecklenburg County, NC, Mitchell County, NC, Polk County, NC, Rutherford County, NC, Yancey County, NC, Cherokee County, SC, Chester County, SC, Greenville County, SC, Laurens County, SC, Spartanburg County, SC, Union County, SC, York County, SC, Carter County, TN, Greene County, TN, Hancock County, TN, Hawkins County, TN, Johnson County, TN, Sullivan County, TN, Unicoi County, TN, Washington County, TN
The radar
The Greer radar (KGSP), 94 km from the middle of the area, began a volume at 02:45 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.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 20%
- One or more EF2 to EF5 tornadoes
- 5%
- Ten or more severe wind reports
- 80%
- One or more gusts of 65 knots or more
- 40%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 20%
- Six or more combined severe hail and wind reports
- 90%
Warnings issued inside it
10 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 10, 10:54 PM EDT | Severe Thunderstorm Warning | GSP | Alexander, Caldwell, Catawba, Iredell | 66 min |
| May 10, 10:58 PM EDT | Severe Thunderstorm Warning | MRX | Greene, Hancock, Hawkins | 47 min |
| May 10, 11:17 PM EDT | Severe Thunderstorm Warning | MRX | Greene, Unicoi, Washington | 43 min |
| May 10, 11:22 PM EDT | Severe Thunderstorm Warning | GSP | Buncombe, Burke, Caldwell, Catawba, Cleveland, Henderson and 5 more | 53 min |
| May 10, 11:30 PM EDT | Severe Thunderstorm Warning | GSP | Cabarrus, Iredell, Mecklenburg, Rowan | 60 min |
| May 10, 11:45 PM EDT | Severe Thunderstorm Warning | GSP | Buncombe, Haywood, Henderson, Madison, Transylvania | 60 min |
| May 10, 11:55 PM EDT | Severe Thunderstorm Warning | GSP | Alexander, Burke, Cabarrus, Caldwell, Catawba, Cleveland and 5 more | 65 min |
| May 11, 12:04 AM EDT | Severe Thunderstorm Warning | GSP | Buncombe, Cleveland, Gaston, Henderson, Lincoln, Polk and 1 more | 56 min |
| May 11, 12:36 AM EDT | Severe Thunderstorm Warning | GSP | Cabarrus, Gaston, Mecklenburg, Union | 54 min |
| May 11, 12:51 AM EDT | Severe Thunderstorm Warning | GSP | Cleveland, Gaston | 54 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Greensboro/Hi Pt, NC (KGSO), launched 00:00Z, 2.7 hours before the alert went out and 201 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.
- Mixed-layer CAPE
- 694 J/kg
- Mixed-layer CIN
- -146 J/kg
- Mixed-layer LCL
- 1286 m above ground
- 0-6 km bulk shear
- 50 kt
- 0-1 km storm-relative helicity
- 109 m²/s²
- 0-3 km storm-relative helicity
- 420 m²/s²
- Significant tornado parameter
- 0.3
- Supercell composite
- 11.6
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 10, 9:01 PM EDT | Mesoscale Discussion | SPC | Alexander, Alleghany, Anson, Ashe, Avery, Bladen and 46 more | 59 min |
| May 10, 10:18 PM EDT | Mesoscale Discussion | SPC | Alexander, Ashe, Avery, Buncombe, Burke, Caldwell and 16 more | 27 min |
| May 11, 12:14 AM EDT | Mesoscale Discussion | SPC | Alexander, Alleghany, Ashe, Avery, Buncombe, Burke and 17 more | 61 min |
| May 11, 2:37 AM EDT | Mesoscale Discussion | SPC | Alexander, Ashe, Avery, Buncombe, Burke, Caldwell and 14 more | 23 min |
| May 11, 6:06 PM EDT | Mesoscale Discussion | SPC | Buncombe, Haywood, Henderson, Jackson, Polk, Transylvania | 54 min |
| May 11, 12:41 AM EDT | Severe Thunderstorm Watch | SPC | Aiken, Bamberg, Barnwell, Calhoun, Chesterfield, Clarendon and 11 more | 3 hr |
| May 11, 1:35 AM EDT | Mesoscale Discussion | SPC | Berkeley, Charleston, Darlington, Dorchester, Florence, Georgetown and 2 more | 25 min |
| May 11, 1:41 AM EDT | Severe Thunderstorm Watch | SPC | Berkeley, Charleston, Darlington, Dillon, Dorchester, Florence and 5 more | 3 hr |
| May 11, 3:34 AM EDT | Mesoscale Discussion | SPC | Berkeley, Charleston, Chesterfield, Colleton, Darlington, Dillon and 7 more | 56 min |
Nearby
Severe Thunderstorm Watches in North Carolina, 2011Severe Thunderstorm Watches in Tennessee, 2011Severe Thunderstorm Watches in South Carolina, 2011Every severe thunderstorm watch in 2011
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.