In this blog entry, we will be taking a look at some of the best and worst National Weather Service Offices in regards to their tornado warning accuracy for 2014-2020. In this review, we are only including offices that averaged issuing 10 tornado warnings per year for the given timeframe. This resulted in a population of 72 offices. For reference, the average tornado warning verification rate for the entire National Weather Service for the timeframe was 25.59%. Yes. You read that correctly. NWS Tornado Warnings only verify 25.59% of the time. And remember, “verify” for this discussion means a tornado was observed or damage was determined to be from a tornado in the warned area during the time that it was in effect. Again all 2014-2020 NWS Tornado Verification Statistics were compiled through the use of the Storm Prediction Center’s Severe Weather Event Summaries and Iowa State’s IEM COW (NWS Storm Based Verification) webpages.
Top 15 NWS Offices in Tornado Warning Verification Rate from 2014-2020
Top 15 NWS Offices with the Least False Alarms from 2014-2020
Four offices appear in the Top 15 of verification rate and fewest false alarms: NWS Wichita, NWS Columbia, NWS Chicago, and NWS Lubbock. It should be noted, however, that none of these four offices averaged issuing more than 18 tornado warnings per year. It’s a bit more impressive to see an office like NWS Birmingham rank third in verification rate. They averaged issuing 42 tornado warnings per year.
Bottom 15 NWS Offices in Tornado Warning Verification Rate from 2014-2020
Bottom 15 NWS Offices with the Most False Alarms from 2014-2020
Five offices appear in the Bottom 15 of verification rate and most false alarms: NWS Mobile, NWS New Orleans, NWS Little Rock, NWS Lake Charles, and NWS Houston/Galveston. A large portion, but definitely not all, of these false alarms and extremely poor verification rates from offices close to the Gulf of Mexico can be attributed to tornado warnings issued during landfalling tropical systems. The problem is that there are still tornado warnings being pushed out to the public with no tornado occurring. Also, there are plenty of offices on these two “bottom” lists that are not issuing tropical tornado warnings. For example, NWS Blacksburg issued 104 tornado warnings from 2014-2020 and only 10 of those verified. 10.
In a future blog, we will discuss what possible correlations can be drawn between verification rates/false alarms and tornado related fatalities. Obviously, there are numerous factors that play a role in why someone perished in a tornado. We recognize that fact. But, we also cannot ignore issues that we as a weather community can mitigate to help reduce fatalities from our side.
Don’t forget, Spring Severe Weather Season is right around the corner. Be sure to have multiple ways to receive warnings, including our Imminent Tornado Alerting Service (ITAS). Click here to sign up today.