Alert archive / Louisiana

Weather alerts in Louisiana, 2019

3,905 weather alerts in 2019, 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 2019. Tap one for its archive.

Alerts
3,905
Warnings
1,759
Watches
104
Advisories
608
Busiest month
April751 alerts
Busiest day
April 18, 2019125 alerts

Over time

By month

Warning verification

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

46 of 206 tornado warnings covering Louisiana in 2019 had a tornado report inside them; 81 of 122 tornado reports fell inside a warning, on average 13 minutes after it went out.

Louisiana, 2019

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
Tornado warnings2064678%12266%13 min
Severe thunderstorm warnings49722056%43866%23 min
Flash flood warnings1367446%15984%98 min

Each office's whole area, 2019

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
NWS Jackson, MS: tornado warnings1225059%18484%23 min
NWS Jackson, MS: severe thunderstorm warnings40424639%71174%26 min
NWS Jackson, MS: flash flood warnings1177833%27881%88 min
NWS New Orleans, LA: tornado warnings1171686%4166%10 min
NWS New Orleans, LA: severe thunderstorm warnings1784276%13151%17 min
NWS New Orleans, LA: flash flood warnings411466%2781%71 min
NWS Shreveport, LA: tornado warnings922474%6073%16 min
NWS Shreveport, LA: severe thunderstorm warnings32718045%44972%23 min
NWS Shreveport, LA: flash flood warnings473232%9082%115 min
NWS Lake Charles, LA: tornado warnings711480%3459%17 min
NWS Lake Charles, LA: severe thunderstorm warnings1194265%12468%25 min
NWS Lake Charles, LA: flash flood warnings995643%13191%97 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

3,905 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.

24 more counties

The busiest days

Days with the most alerts issued, by UTC date.

Nearby

Alerts in force nowTornadoes on recordThe radar archive20182020

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.