Weather alerts in Louisiana, 2008
2,402 weather alerts in 2008, 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 2008. Tap one for its archive.
- Alerts
- 2,402
- Warnings
- 1,634
- Watches
- 148
- Advisories
- 357
- Busiest month
- September462 alerts
- Busiest day
- September 3, 2008115 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
64 of 316 tornado warnings covering Louisiana in 2008 had a tornado report inside them; 94 of 131 tornado reports fell inside a warning, on average 15 minutes after it went out.
Louisiana, 2008
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 316 | 64 | 80% | 131 | 72% | 15 min |
| Severe thunderstorm warnings | 561 | 214 | 62% | 496 | 66% | 22 min |
| Flash flood warnings | 125 | 49 | 61% | 105 | 90% | 88 min |
Each office's whole area, 2008
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Jackson, MS: tornado warnings | 315 | 78 | 75% | 186 | 81% | 23 min |
| NWS Jackson, MS: severe thunderstorm warnings | 823 | 370 | 55% | 1,059 | 65% | 21 min |
| NWS Jackson, MS: flash flood warnings | 136 | 56 | 59% | 134 | 79% | 96 min |
| NWS New Orleans, LA: tornado warnings | 147 | 18 | 88% | 38 | 61% | 13 min |
| NWS New Orleans, LA: severe thunderstorm warnings | 192 | 54 | 72% | 146 | 59% | 24 min |
| NWS New Orleans, LA: flash flood warnings | 30 | 8 | 73% | 17 | 76% | 48 min |
| NWS Lake Charles, LA: tornado warnings | 150 | 26 | 83% | 61 | 70% | 12 min |
| NWS Lake Charles, LA: severe thunderstorm warnings | 166 | 56 | 66% | 139 | 67% | 22 min |
| NWS Lake Charles, LA: flash flood warnings | 47 | 12 | 74% | 26 | 85% | 86 min |
| NWS Shreveport, LA: tornado warnings | 77 | 28 | 64% | 61 | 66% | 15 min |
| NWS Shreveport, LA: severe thunderstorm warnings | 461 | 201 | 56% | 484 | 74% | 23 min |
| NWS Shreveport, LA: flash flood warnings | 64 | 42 | 34% | 114 | 89% | 69 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
2,402 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.
- East Carroll Parish240
- Madison Parish233
- Tensas Parish222
- Rapides Parish221
- Morehouse Parish221
- Concordia Parish219
- Franklin Parish214
- Catahoula Parish213
- Richland Parish213
- West Carroll Parish213
- Bossier Parish211
- Caddo Parish206
- Webster Parish202
- Bienville Parish199
- Union Parish198
- Claiborne Parish194
- Saint Landry Parish193
- Ouachita Parish190
- Natchitoches Parish190
- Allen Parish187
- Jackson Parish187
- De Soto Parish186
- Lincoln Parish185
- Evangeline Parish183
- Vernon Parish182
- Sabine Parish181
- Grant Parish179
- Red River Parish179
- LaSalle Parish178
- Winn Parish178
- Saint Martin Parish175
- Caldwell Parish173
- Avoyelles Parish172
- Beauregard Parish171
- Washington Parish169
- Saint Tammany Parish167
- Lafayette Parish165
- Saint Helena Parish156
- Tangipahoa Parish152
- East Baton Rouge Parish148
24 more counties
- East Feliciana Parish147
- Pointe Coupee Parish146
- West Feliciana Parish144
- Saint Bernard Parish142
- Saint John the Baptist Parish132
- West Baton Rouge Parish131
- Iberville Parish129
- Calcasieu Parish129
- Saint James Parish123
- Livingston Parish122
- Acadia Parish118
- Assumption Parish114
- Vermilion Parish107
- Jefferson Davis Parish106
- Ascension Parish100
- Orleans Parish93
- Jefferson Parish90
- Saint Charles Parish88
- Lafourche Parish87
- Plaquemines Parish86
- Cameron Parish81
- St. Mary Parish75
- Iberia Parish74
- Terrebonne Parish65
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordThe radar archive20072009
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.