Warren Eckels
(I'll confess, part of the reason I'm posting this is so that we no longer have 666 topics...but if I didn't have a gig Sunday afternoon I might now be planning some kicks on 66 (I-57) between Joliet and Champaign)
The 12 UTC NAM and MRF are setting up interesting weather for much of northern and central Illinois, Wisconsin SE of I-43 and Indiana west of a South Bend-Terre Haute line.
The low in Kentucky this morning will weaken and move east, so Gulf moisture will have fewer problems entering the region this weekend.
On the side of severe weather, 0-6 km shear will be about 35 knots, a moderate jet streak (50-80 kt) will be crossing the Mississippi, moderate levels of humidity at 700 mb favor severe thunderstorms and surface dewpoints near or above 70 F are expected. Temperatures of 17-18 C at 850 mb indicate that areas with much sun will see 85 F by 1 pm. Finally, SW winds at the surface around 10 kt will keep Lake Michigan from slapping down convection near Chicago.
On the side against severe weather, we will be in the right-front quadrant of the jet streak, which favors sinking air. Whatever we do get Sunday will probably not be a tornado, since wind shear would be horizontal (at least until frontal passage overnight).
What happens on the eastern Plains Saturday will affect Sunday afternoon's weather and can work either way. An active Saturday in western Iowa means MCSs and lots of cloud cover Sunday, which in turn lowers temperatures. Move Saturday's activity east to the Mississippi, and the MCSs clear Illinois by dawn after dumping some rain and developing a pool of low-level moist air that would give convection an extra kick.
Sunday night, a cold front should pass through, probably attended with the usual line of heavy thunderstorms.
The 12 UTC NAM and MRF are setting up interesting weather for much of northern and central Illinois, Wisconsin SE of I-43 and Indiana west of a South Bend-Terre Haute line.
The low in Kentucky this morning will weaken and move east, so Gulf moisture will have fewer problems entering the region this weekend.
On the side of severe weather, 0-6 km shear will be about 35 knots, a moderate jet streak (50-80 kt) will be crossing the Mississippi, moderate levels of humidity at 700 mb favor severe thunderstorms and surface dewpoints near or above 70 F are expected. Temperatures of 17-18 C at 850 mb indicate that areas with much sun will see 85 F by 1 pm. Finally, SW winds at the surface around 10 kt will keep Lake Michigan from slapping down convection near Chicago.
On the side against severe weather, we will be in the right-front quadrant of the jet streak, which favors sinking air. Whatever we do get Sunday will probably not be a tornado, since wind shear would be horizontal (at least until frontal passage overnight).
What happens on the eastern Plains Saturday will affect Sunday afternoon's weather and can work either way. An active Saturday in western Iowa means MCSs and lots of cloud cover Sunday, which in turn lowers temperatures. Move Saturday's activity east to the Mississippi, and the MCSs clear Illinois by dawn after dumping some rain and developing a pool of low-level moist air that would give convection an extra kick.
Sunday night, a cold front should pass through, probably attended with the usual line of heavy thunderstorms.
