Monitoring of concurrent, co-located tornado and flash flood (TORFF) warnings

Below is the most recent image showing overlapping tornado and flash flood warning polygons thus far in 2023. Warnings are shown if they overlap in space and are valid within 30 minutes of one another, calculated as described in Nielsen et al. (2015, Weather and Forecasting). The images are updated once per day at approximately 1200 UTC. The images are zoomed in on the region where overlapping TORFF warnings are most frequently observed.

Images last updated 2243 UTC Friday September 1 2023. (click image to embiggen)

The ten most recent TORFF overlapping warnings in 2023 are:

ILM issued TOR warning at: 202308310208 and FF warning at: 202308310225
CHS issued TOR warning at: 202308302046 and FF warning at: 202308302047
CRP issued TOR warning at: 202308221623 and FF warning at: 202308221614
CRP issued TOR warning at: 202308221614 and FF warning at: 202308221614
CRP issued TOR warning at: 202308221610 and FF warning at: 202308221614
SGX issued TOR warning at: 202308202237 and FF warning at: 202308202246
BOX issued TOR warning at: 202308181345 and FF warning at: 202308181336
BOX issued TOR warning at: 202308181345 and FF warning at: 202308181318
BOX issued TOR warning at: 202308181322 and FF warning at: 202308181336
BOX issued TOR warning at: 202308181322 and FF warning at: 202308181318

Download the text file with the details of this year's overlapping warnings.

All TORFF Warning Intersections (n=4173) from 2008-2019:

Map of "Verified" TORFF Events from 2003-2018:

"Verified" TORFF events are identified by finding intersections between flash flood local storm reports (LSRs) and official tornado paths that were reported within three hours of one another, allowing for up to a 50 km spacing between the two. Five different spacing thresholds are tested from 10 km to 50 km, where the 10 km (50 km) spacing creates the most (least) conservative event totals. Between 25 and 75 "verified" TORFF events occur on average per year, depending on spatial threshold chosen. Discussion of the specific methods can be found in Nielsen (2019) and Henderson et al. (2020, Weather and Forecasting).

Select a Spatial Buffer:

TORFF Warning Intersections for Select U.S. Tropical Cyclones:

Select a Storm:

This research is sponsored by NOAA grant NA15OAR4590233, in support of the 2016 VORTEX-SE field campaign.

DISCLAIMER: The images and data on this site are intended for meteorological education and research purposes and, although they should generally be up to date, are not monitored at all times. Do not use for making decisions where money or lives are at stake. For official forecasts and warnings, visit the National Weather Service.