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 2024. 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 0930 UTC Monday March 11 2024. (click image to embiggen)The ten most recent TORFF overlapping warnings in 2023 are:
TAE issued TOR warning at: 202403090738 and FF warning at: 202403090808JAN issued TOR warning at: 202403082209 and FF warning at: 202403082225
JAN issued TOR warning at: 202403082209 and FF warning at: 202403082239
LCH issued TOR warning at: 202402120513 and FF warning at: 202402120500
LIX issued TOR warning at: 202401241652 and FF warning at: 202401241637
RAH issued TOR warning at: 202401092334 and FF warning at: 202401092304
RNK issued TOR warning at: 202401092153 and FF warning at: 202401092134
RNK issued TOR warning at: 202401092151 and FF warning at: 202401092134
RAH issued TOR warning at: 202401092034 and FF warning at: 202401092007
GSP issued TOR warning at: 202401092008 and FF warning at: 202401091951
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.