A severe weather outbreak is imminent for the surrounding Chicago area today particularity over Indiana. Lets take a look at the ingredients we have to produce this outbreak that will have multiple tornadoes spur. Focus on Illinois and Indiana areas.
Very strong upper level jet stream. Area in orange represents upper level winds of over 120 knots.
Very strong low level winds that are creating a strong wind shear compared to wind direction at upper levels, this creates rotation in the storms which produces tornados..
Strong instability in the atmosphere as measured by Convective Available Potential Energy (CAPE). This basically tells you how much momentum an air parcel will have once it is allowed to rise due to an approaching cold front. The higher the CAPE the larger the storms will be.
Combine all these factors with a powerful approaching cold front running into very warm moist air for this time of year and you have a very severe weather outbreak.
Here is the simulated radar for later today..notice the individual super cell storms firing up over Indiana and Illinois.
This will be a big news maker today.
More on long term very dynamic weather pattern tonight. A lot to discuss