Alert archive / North Carolina / Severe Thunderstorm Warnings
Severe Thunderstorm Warnings in North Carolina, 2011
1,254 severe thunderstorm warnings in 2011. An alert counts here when it covered any part of the state, so the counties below add up to more than the state. The archive of severe thunderstorm warnings reaches back to 1986.
Severe Thunderstorm Warnings by county
Each county as a circle sized by its count in 2011. Tap one for its archive.
- Severe Thunderstorm Warnings
- 1,254
- Busiest month
- June404 severe thunderstorm warnings
- Busiest day
- April 9, 201148 severe thunderstorm warnings
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
941 of 1,256 severe thunderstorm warnings covering North Carolina in 2011 had a qualifying storm report inside them; 1,900 of 2,291 hail, wind and damage reports fell inside a warning, on average 23 minutes after it went out.
North Carolina, 2011
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Severe thunderstorm warnings | 1,256 | 941 | 25% | 2,291 | 83% | 23 min |
Each office's whole area, 2011
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Morristown, TN: severe thunderstorm warnings | 400 | 287 | 28% | 533 | 78% | 23 min |
| NWS Greenville-Spartanburg, SC: severe thunderstorm warnings | 693 | 551 | 20% | 1,309 | 89% | 26 min |
| NWS Blacksburg, VA: severe thunderstorm warnings | 576 | 456 | 21% | 1,384 | 77% | 23 min |
| NWS Raleigh, NC: severe thunderstorm warnings | 360 | 267 | 26% | 788 | 83% | 21 min |
| NWS Newport/Morehead City, NC: severe thunderstorm warnings | 82 | 55 | 33% | 157 | 66% | 22 min |
| NWS Wakefield, VA: severe thunderstorm warnings | 241 | 150 | 38% | 386 | 79% | 19 min |
| NWS Wilmington, NC: severe thunderstorm warnings | 166 | 123 | 26% | 383 | 83% | 28 min |
An office's figures cover every county it serves, including across state lines.
Verified by the Iowa Environmental Mesonet's Cow, which matches each storm-based warning with the local storm reports inside its polygon while it was in force, within 15 km of its edge: a tornado warning counts as verified on a tornado report, a severe thunderstorm warning on hail of 1 inch or more, a gust of 58 mph or more, or wind damage, a flash flood warning on a flash flood report. The false alarm ratio is the share of warnings with no such report; "inside a warning" is the probability of detection, the share of reports that fell inside one; lead time runs from the warning's issue to each report inside it, counting zero for a report that came first. A warning with no report is not proof nothing happened: reports come from spotters, the public and damage surveys, and are thin where few people live.
The alerts
1,254 alerts are too many to list on one page. Narrow it to a product above, to a month in the chart, or to a county.
By county
Every county with at least one alert. A county page lists each alert that covered it.
- Surry County95
- Wilkes County91
- Burke County67
- Cleveland County64
- Mecklenburg County64
- Gaston County64
- Catawba County63
- Alleghany County61
- Lincoln County59
- Iredell County58
- Rutherford County57
- Stokes County56
- Wake County56
- Buncombe County56
- McDowell County54
- Ashe County52
- Yadkin County51
- Caldwell County50
- Henderson County47
- Rowan County46
- Polk County45
- Rockingham County45
- Harnett County43
- Franklin County43
- Columbus County43
- Transylvania County42
- Cabarrus County41
- Union County40
- Alexander County39
- Robeson County39
- Yancey County38
- Johnston County38
- Durham County38
- Bladen County38
- Watauga County37
- Macon County35
- Nash County34
- Madison County33
- Jackson County33
- Davidson County33
60 more counties
- Guilford County33
- Chatham County33
- Granville County33
- Cumberland County32
- Richmond County32
- Forsyth County31
- Davie County31
- Halifax County30
- Randolph County29
- Hoke County29
- Caswell County29
- Cherokee County28
- Sampson County28
- Wayne County28
- Haywood County28
- Avery County27
- Mitchell County26
- Edgecombe County26
- Wilson County26
- Montgomery County25
- Craven County25
- Jones County24
- Moore County23
- Warren County22
- Northampton County22
- Brunswick County22
- Orange County21
- Anson County21
- Beaufort County21
- Scotland County21
- Swain County20
- Onslow County20
- Lee County20
- Clay County19
- Alamance County19
- Pender County19
- Pitt County19
- Stanly County19
- Person County18
- Vance County18
- Graham County17
- Duplin County16
- Lenoir County15
- Gates County15
- Greene County14
- Martin County14
- Hertford County14
- Bertie County13
- Pamlico County11
- Washington County10
- Camden County9
- New Hanover County9
- Perquimans County8
- Chowan County7
- Pasquotank County7
- Tyrrell County6
- Currituck County6
- Hyde County6
- Carteret County6
- Dare County5
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordThe radar archive20102012
Sources
National Weather Service watches, warnings, advisories and statements from the Iowa Environmental Mesonet's VTEC archive, which reconstructs tornado, severe thunderstorm, flash flood and marine warnings back to 1986 from the NWS text archive. Storm Prediction Center watches and mesoscale discussions from SPC's archive through the Mesonet. County centers from the US Census Bureau. Warning verification from the Mesonet's Cow. Rebuilt daily.