The Tornado Intensity Model (TIM) was developed similar to the current significant tornado mask used today by forecasters, however the model has some tweaks to it to pin down location that may experience EF0 to EF5 type tornadoes and it predicted Northern Illinois’ Wedge Tornado of April 9, 2015. Read on for details.
On the morning of April 9th, 2015 we ran our Tornado Intensity Model (TIM) and found out that Northern Illinois may very well see a stronger tornado scenario. The rest of the front would see much weaker activity along the front through Missouri and into Arkansas. Given what this showed, we put strong tornado wording for these zones on our forecast grid.
A powerful tornado struck Northern Illinois, within our zone for EF4 being possible. This meant that the model was correct, even showing a weakening trend as the storm would move through toward the Wisconsin/Illinois border.
Our model also contains a mask within it for updraft and downdraft interactions. When an updraft (containing the tornado zone) moves into the storm’s downdraft you get a weak and/or non-developing tornado situation where the updraft cools too fast and the rising warm upward motion making the tornado possible gets removed from existence. This is factored into the work down here.