Alert archive / Georgia / Jackson County / Flash Flood Warnings

Flash Flood Warnings in Jackson County, Georgia, 2009

2 flash flood warnings in 2009. An alert counts here when it covered this county. The archive of flash flood warnings reaches back to 1986.

Jackson County and its neighbors

Each county as a circle sized by its count in 2009. Tap one for its archive.

Flash Flood Warnings
2
Busiest month
September1 flash flood warnings
Busiest day
September 21, 20091 flash flood warnings

Over time

By month

Warning verification

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

1 of 2 flash flood warnings covering Jackson County in 2009 had a flash flood report inside them; 1 of 1 flash flood reports fell inside a warning, on average 187 minutes after it went out.

Jackson County, 2009

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
Flash flood warnings2150%1100%187 min

Each office's whole area, 2009

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
NWS Atlanta, GA: flash flood warnings582360%5165%150 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

Every alert, in the order issued. Times are local, Eastern Time. Each opens its own page with the text, the map, the radar and the sounding.

IssuedProductOfficeLasted
Sep 21, 3:53 AM EDTFlash Flood WarningFFC6 hr
Oct 12, 10:23 AM EDTFlash Flood WarningFFC6 hr

The busiest days

Days with the most alerts issued, by UTC date.

Nearby

Alerts in force nowTornadoes on recordForecastThe 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.