It has been three years since the violent and deadly Rochelle/Fairdale, EF-4 tornado that occurred across northern Illinois that evening, along with 10 other tornadoes across the state that day. Even though we had accumulating snow across portions of Illinois, this is a reminder that we are now in the heart of tornado season across Illinois and this could easily happen again and we all need to be ready and prepare, not be complacent and say, “it never happens here”. It very well can happen here and it will.
This was a warm and very humid day across most of Illinois with temperatures in the 70’s and dew points in the 60’s, leading to plenty of instability for thunderstorms to tap. Long story short, the environment was more than conducive for severe thunderstorms and tornadoes given all the ingredients were in place (shear, lift, instability, and moisture). The image below is courtesy of the National Weather Service Chicago.
Below is the thunderstorm outlook from the Storm Prediction Center the day of with a large enhanced risk for severe thunderstorms
Also, there was a heightened risk for tornadoes as well along with the threat for significant tornadoes (marked by the hatching below)
Obviously the long track EF-4 tornado stands out below, but not many now there were several other weaker tornadoes across north central Illinois that evening as well, several of them spawned by the same supercell storm that birthed the EF-4 southwest of Rochelle, IL
Below are two radar images during the time of the violent tornado. The first image is when the tornado was just northwest of Rochelle and west of I-39 as I circled both the hook echo and velocity couplet in blue on radar. The stronger/brighter winds on the right side of the radar are showing inbound and outbound winds to and away from the radar (located in Romeoville). This signature shows where the strongest rotation is occurring, and at this time, a very strong tornado.
Below, the tornado is now located east of I-39 continuing northeast and still very strong at this point in time.
Our winter weather expert, Matt, was out storm chasing this day and here are a few of his pictures and a long video of the tornado as it was northeast of Rochelle at this time, getting closer to the town of Fairdale.