Monday, April 02, 2018

Two Historical Tornado Outbreaks

The deadly, Jumbo Tornado Outbreak occurred on April 3rd, 1974 - 44 years ago tomorrow. 

See -

While tomorrow's synoptic setting is not as potent as that associated with the jumbo outbreak, it does bear large-scale similarities to the conditions associated with the infamous Tri-State Tornado of March 18, 1925. Shown below are a couple of recent surface analyses for that event.

The chart above is a surface analysis for 7:00 pm CST on March 18, 1925; while chart below shows the progression of the surface low during the day, as well as the track of Tri-State tornado. The detailed legends for these charts can be found at:

Here are two model forecasts from 00 UTC last evening - above is the NAM surface forecast valid at 7:00 pm CDT tomorrow. Below is the ECMWF forecasts for 500 mb and the surface - also valid at 7:00 pm CDT tomorrow.

It appears that tomorrows large-scale evolution will provide an interesting analog of the conditions that occurred 93 years ago on March 18, 1925.


  1. The Tri-State Tornado surface analysis map is simply beautiful. Nice to see a high quality analysis again!

  2. Thanks Jim - these surface charts involved a substantial effort and many people were involved. We feel they are probably the best that can be done after so many years. Bob