Flash Flood Warnings in New York, 2020

By month

35 of 65 flash flood warnings covering New York in 2020 had a flash flood report inside them; 91 of 100 flash flood reports fell inside a warning, on average 67 minutes after it went out.

New York, 2020

Each office's whole area, 2020

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.

• Queens County10
• Broome County9
• Delaware County8
• Nassau County6
• Cattaraugus County6
• Chenango County6
• Kings County5
• Richmond County5
• Erie County4
• Westchester County4
• Livingston County4
• Bronx County4
• New York County4
• Chautauqua County4
• Niagara County3
• Rockland County3
• Orange County3
• Greene County3
• Chemung County3
• Cortland County3
• Tioga County3
• Genesee County2
• Dutchess County2
• Monroe County2
• Sullivan County2
• Albany County2
• Schoharie County2
• Ulster County2
• Otsego County2
• Madison County2
• Wyoming County1
• Oneida County1
• Putnam County1
• Wayne County1
• St. Lawrence County1
• Essex County1
• Franklin County1
• Allegany County1
• Orleans County1
• Rensselaer County1

1. December 25, 202011flash flood warnings
2. July 11, 20206flash flood warnings
3. August 4, 20205flash flood warnings
4. July 6, 20204flash flood warnings
5. July 8, 20204flash flood warnings
6. September 10, 20203flash flood warnings
7. June 11, 20202flash flood warnings
8. June 22, 20202flash flood warnings
9. July 10, 20202flash flood warnings
10. July 12, 20202flash flood warnings
11. July 16, 20202flash flood warnings
12. August 10, 20202flash flood warnings

Alerts in force nowTornadoes on recordThe radar archive20192021

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.