Alert archive / North Carolina
Weather alerts in North Carolina, 2009
2,996 weather alerts in 2009, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered any part of the state, so the counties below add up to more than the state.
Weather alerts by county
Each county as a circle sized by its count in 2009. Tap one for its archive.
- Alerts
- 2,996
- Warnings
- 1,539
- Watches
- 173
- Advisories
- 824
- Busiest month
- June515 alerts
- Busiest day
- August 5, 200962 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
22 of 86 tornado warnings covering North Carolina in 2009 had a tornado report inside them; 38 of 49 tornado reports fell inside a warning, on average 22 minutes after it went out.
North Carolina, 2009
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 86 | 22 | 74% | 49 | 78% | 22 min |
| Severe thunderstorm warnings | 909 | 448 | 51% | 828 | 87% | 24 min |
| Flash flood warnings | 119 | 68 | 43% | 164 | 80% | 95 min |
Each office's whole area, 2009
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Blacksburg, VA: tornado warnings | 19 | 1 | 95% | 9 | 11% | 4 min |
| NWS Blacksburg, VA: severe thunderstorm warnings | 264 | 144 | 45% | 348 | 82% | 26 min |
| NWS Blacksburg, VA: flash flood warnings | 108 | 53 | 51% | 135 | 81% | 100 min |
| NWS Greenville-Spartanburg, SC: tornado warnings | 33 | 8 | 76% | 15 | 93% | 21 min |
| NWS Greenville-Spartanburg, SC: severe thunderstorm warnings | 394 | 237 | 40% | 457 | 86% | 26 min |
| NWS Greenville-Spartanburg, SC: flash flood warnings | 55 | 40 | 27% | 103 | 73% | 94 min |
| NWS Wakefield, VA: tornado warnings | 35 | 3 | 91% | 9 | 44% | 10 min |
| NWS Wakefield, VA: severe thunderstorm warnings | 290 | 137 | 53% | 332 | 80% | 19 min |
| NWS Wakefield, VA: flash flood warnings | 19 | 14 | 26% | 21 | 81% | 40 min |
| NWS Morristown, TN: tornado warnings | 41 | 11 | 73% | 14 | 93% | 22 min |
| NWS Morristown, TN: severe thunderstorm warnings | 335 | 252 | 25% | 434 | 87% | 26 min |
| NWS Morristown, TN: flash flood warnings | 39 | 29 | 26% | 59 | 76% | 75 min |
| NWS Newport/Morehead City, NC: tornado warnings | 33 | 9 | 73% | 18 | 78% | 22 min |
| NWS Newport/Morehead City, NC: severe thunderstorm warnings | 126 | 38 | 70% | 88 | 83% | 20 min |
| NWS Newport/Morehead City, NC: flash flood warnings | 0 | 1 | 0% | |||
| NWS Raleigh, NC: tornado warnings | 24 | 9 | 63% | 18 | 94% | 21 min |
| NWS Raleigh, NC: severe thunderstorm warnings | 333 | 181 | 46% | 356 | 88% | 23 min |
| NWS Raleigh, NC: flash flood warnings | 41 | 20 | 51% | 56 | 84% | 66 min |
| NWS Wilmington, NC: tornado warnings | 8 | 1 | 88% | 3 | 33% | 8 min |
| NWS Wilmington, NC: severe thunderstorm warnings | 110 | 42 | 62% | 100 | 77% | 22 min |
| NWS Wilmington, NC: flash flood warnings | 2 | 2 | 0% | 6 | 100% | 65 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
2,996 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 product
Every kind of product issued here, grouped by hazard. Each opens the same place narrowed to that product.
By county
Every county with at least one alert. A county page lists each alert that covered it.
- Johnston County186
- Henderson County181
- Burke County172
- Caldwell County171
- Rutherford County170
- Buncombe County166
- Ashe County165
- McDowell County162
- Polk County159
- Jackson County156
- Sampson County156
- Wake County153
- Transylvania County151
- Wayne County151
- Mecklenburg County150
- Wilson County150
- Madison County147
- Swain County146
- Wilkes County146
- Beaufort County146
- Pitt County146
- Cabarrus County145
- Macon County145
- Nash County145
- Haywood County144
- Currituck County144
- Mitchell County143
- Bladen County143
- Jones County143
- Avery County142
- Edgecombe County142
- Alleghany County142
- Watauga County141
- Harnett County141
- Yancey County139
- Cleveland County138
- Halifax County138
- Columbus County138
- Chatham County137
- Cumberland County137
60 more counties
- Lenoir County135
- Greene County134
- Graham County133
- Randolph County133
- Duplin County133
- Martin County132
- Gaston County131
- Iredell County130
- Warren County129
- Rowan County128
- Union County128
- Granville County128
- Durham County126
- Franklin County126
- Orange County125
- Robeson County125
- Hoke County124
- Moore County123
- Surry County122
- Guilford County121
- Vance County121
- Lincoln County120
- Person County119
- Lee County118
- Gates County118
- Craven County118
- Davidson County117
- Cherokee County117
- Richmond County117
- Catawba County116
- Montgomery County116
- Scotland County116
- Alamance County115
- Stanly County114
- Pamlico County114
- Caswell County113
- Hertford County112
- Northampton County112
- Alexander County111
- Anson County109
- Pasquotank County109
- Onslow County109
- Davie County107
- Hyde County107
- Washington County106
- Bertie County106
- Camden County106
- Perquimans County106
- Yadkin County105
- Chowan County105
- Rockingham County100
- Clay County100
- Forsyth County97
- Tyrrell County97
- Stokes County95
- Pender County91
- Brunswick County83
- Dare County79
- Carteret County79
- New Hanover County68
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordThe radar archive20082010
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.