RUNNING EXTRA: Some commentary on the storm, from the Northern Illinois weatherman.
Very busy day today as you can imagine. The stationary front to our south yesterday morning came back as a warm front and was right around U.S. route 30 at 6 PM...and when a thunderstorm started developing in Marshall county and moved northeast across the frontal boundary, it encountered much better wind shear, which caused the storm to rotate almost immediately, and tornado soon thereafter. I knew there was enough energy for thunderstorms, but no one thought there would be enough heating/instability for that. This was eerily reminiscent of the Utica/Joliet tornadoes this spring...same thing...warm front approaches, and there's just enough instability for the storms to become severe mainly if they interact with the front. As you can tell, we need to learn more about that. Could be an interesting grad student thesis. I think I'll pass that along to someone who might want a topic of study... In any case, first, mega kudos to the National Weather Service office in Romeoville for very timely warnings...they were on top of it once the storm started to rotate. The supercell produced 4 tornadoes, as far as I know ... one just south of DeKalb (caught on tape and shown on WREX-TV), two near Burlington, and another one also captured on home video in McHenry (as seen on WBBM-TV in Chicago).(That last one has been running on the Weather Channel.) And it's not over yet.
Monday-end of next week...as the models have shown the last several days, Monday-Wednesday we start comfortable and slowly warm into the 80s. But by Thursday through next weekend, we could enter another stormy pattern, with highs in the 80s and periods of showers and thunderstorms as fronts try to move through the area. So, look for above average temperatures through Friday, near average through Tuesday, then above average, with lower confidence, for the latter half of next week. Rainfall will be above to much above average, with localized flooding still possible through Saturday of this week, and then more storms late next week. Watch our website and emails for further updates as our wild spring/summer weather continues. Yesterday marks the 4th time the sirens have been hit in DeKalb this year, and the 5th tornado warning for our county so far this season. Stay tuned and we'll have the latest as storms develop around the area.