8/5/07: FCST IL/WI/IA/MN/MI/IN/OH

[David Draun]

Some fairly good chances for isolated to scattered severe storms north and south of a Des Moines to Cleveland line. Looks like W-E moving clusters and lines with damaging winds the main threat, but some low level directional shear shows some slight supercell/tornado potential. SPC has 5% painted here, though I would go 2%, since I don't see anything in the setup that just screams "Tornado!" I'm thinking of heading out locally this afternoon if anything looks interesting. Storms on the back side of current MCS right now are intensifying over my area rather than fizzling to nothing, that has to mean something. Pockets of nice SR-helicity starting to show up in E IA/ W IL. The 21Z RUC model shows the best CAPE in SW IA but the best shear will be farther east over IL. The warm front is backing winds nicely in NW IN/ NE IL. The satellite shows some clearing behind the MCS. Any thoughts?

 

[David Draun]

Well, it appears the SPC agreed with me, lol. Still looks like a good threat for storms this afternoon with a few supercells possible. Shear no longer suggests there will be anything tornadic unless a cell can root on an old outflow boundary. Helicities are way down since this morning with the highest values farther east. Still, theres only weak capping and SBCAPES and MLCAPES starting to push 4500 J/kg respectively, especially to the west in IA. It still looks good for storms, and I wouldn't doubt SPC issuing an MD and an eventual severe-watch in the next few hours. I would like to see more clear-air cumulus on the satellite though, still lots of haze and high/mid-level cloudiness. Very juicy here though with an 85/73 being observed.

EDIT: Things look to be initiating shortly, as blips are popping in W IL.

 

[Jim Hunt]

Lots of mid level cloud deck in IN but we are still at 86 with a 77 dew point. The barometer has been on a steady decline all day and is still dropping at a slow rate (lowest in a couple of weeks).

Cells moving from IL to IN are building but nothing close to severe. I keep thinking today will be a bust for our area.