It is finally here! My first chase of the year will be tomorrow. As of right now, I’m not sure what to expect. I could see several brief tornadoes, or nothing but rain showers. It all depends on how things play out overnight and early tomorrow. The one thing I know for sure is that a warm front with a steep temperature gradient will be situated across northern or central Illinois, and the last time that happened was when I got my first tornado! The middle of April has been good to me the last couple years!
A surface low is forecast to slowly move east through northern Missouri overnight and through the day tomorrow. A robust warm sector will feature dewpoints reaching the mid-60s. As mentioned above, a warm front will be mostly stationary to the east of the low, and a strong cold front will trail to the south. Storms will be along the cold front, but I expect this to be mainly linear, and a straight-line wind damage event. The best chance for tornadoes should be along the warm front, just to the east of the surface low where surface winds will be stronger, and more southeasterly. One of the main things I’ve learned in my few years of chasing is that storms love boundaries, and I’ve seen some pretty good storms develop along a boundary on an otherwise weak setup.
There are a couple concerns for me with this setup. First of all, there should be ongoing convection from today’s activity lingering around in the warm sector in the morning. If there is a lot of it, and a lot of cloud cover, it could really put a damper on organized supercells later in the day. However, today’s activity has been pretty limited thus far, so there may not be much left by sunrise. Also, the last RAP model guidance does not show anything more than isolated light showers in the morning.
My second concern is a fairly weak amount of speed shear in the lower levels of the atmosphere. While 50 knots of surface to 500 mb shear looks good, it is only around 30-35 knots from the surface to 700 mb. On the plus side, this means slower storm motions in the range of 20-25 knots, which is very chaseable. The shear should be enhanced along the front, however, and especially near the surface low where there will be greater directional shear. Even with those things considered, this hodograph from Quincy, IL at 00z looks pretty promising.
I haven’t picked an exact target yet, because I’m waiting to see where things are in the morning. Prior to today, models had the surface low further to the northeast. I do know that my target will be the warm front just east of the surface low. No matter how the day turns out, it’ll be great to be chasing again!