Alert archive / North Carolina

Weather alerts in North Carolina, 2010

4,255 weather alerts in 2010, 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 2010. Tap one for its archive.

Alerts
4,255
Warnings
1,482
Watches
159
Advisories
895
Busiest month
July775 alerts
Busiest day
August 5, 2010118 alerts

Over time

By month

Warning verification

How often warnings here had a storm report inside them, and how much warning the reports had.

18 of 111 tornado warnings covering North Carolina in 2010 had a tornado report inside them; 31 of 39 tornado reports fell inside a warning, on average 19 minutes after it went out.

North Carolina, 2010

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
Tornado warnings1111884%3979%19 min
Severe thunderstorm warnings76756926%1,19982%23 min
Flash flood warnings17310937%30285%113 min

Each office's whole area, 2010

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
NWS Raleigh, NC: tornado warnings27967%21100%19 min
NWS Raleigh, NC: severe thunderstorm warnings25918728%47687%22 min
NWS Raleigh, NC: flash flood warnings734045%11283%86 min
NWS Greenville-Spartanburg, SC: tornado warnings501178%1681%16 min
NWS Greenville-Spartanburg, SC: severe thunderstorm warnings47036223%72281%25 min
NWS Greenville-Spartanburg, SC: flash flood warnings563930%9988%108 min
NWS Blacksburg, VA: tornado warnings31294%743%3 min
NWS Blacksburg, VA: severe thunderstorm warnings34427520%84576%23 min
NWS Blacksburg, VA: flash flood warnings1116244%20590%130 min
NWS Wilmington, NC: tornado warnings4175%667%13 min
NWS Wilmington, NC: severe thunderstorm warnings785431%12372%16 min
NWS Wilmington, NC: flash flood warnings14137%5879%198 min
NWS Morristown, TN: tornado warnings30680%989%20 min
NWS Morristown, TN: severe thunderstorm warnings21215825%28979%22 min
NWS Morristown, TN: flash flood warnings231248%2378%67 min
NWS Newport/Morehead City, NC: tornado warnings90100%20%
NWS Newport/Morehead City, NC: severe thunderstorm warnings412344%5480%25 min
NWS Newport/Morehead City, NC: flash flood warnings110%650%43 min
NWS Wakefield, VA: tornado warnings50688%1656%19 min
NWS Wakefield, VA: severe thunderstorm warnings17013322%36282%23 min
NWS Wakefield, VA: flash flood warnings11918%1889%94 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

4,255 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.

60 more counties

The busiest days

Days with the most alerts issued, by UTC date.

Nearby

Alerts in force nowTornadoes on recordThe radar archive20092011

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.