Wednesday, March 10, 2010

1 in a million. So you're tellin' me there's a chance?

Looks like a marginal tornado threat in Illinois and Iowa tomorrow afternoon, but with the day completely free it's big enough for me to ponder that lovely first chase of the year. Last year I was really gungho on a cold core setup in eastern Iowa, but today I've reverted back to the low topped supercell potential in central Illinois. I'd obviously rather avoid Iowa, but the cold core potential was very intriguing on last night's run. Not so much today. Stressing over the models at this point will be pointless though, as it will be a wake up and see type of day. You know, I'm playing with the models now though and it doesn't look entirely unlike a cold core potential in NW and parts of central Illinois right now.

Anyway. I'll make things brief right now and do a better analysis later tonight and tomorrow morning when things are more certain. As of now, I'm still keeping an eye on eastern or southeastern Iowa, but my attention has really drifted from this area. For now, I'm watching somewhere along a line from Galesburg to Peoria to Springfield, IL. LI's will be peaking nicely around -5c or so in this area with very steep lapse rates thanks in part to the very cold upper level temperatures associated with the cold core of the H5 low. The vort max should be located along the Missouri and Iowa border by mid afternoon while a wave kicks out along the surface boundary in SE Iowa and W Illinois. Convection should begin early, initially in southern Iowa, and then arcing down towards western Illinois by early afternoon. In a day like this, being at your target location by noon would not hurt. Should surface heating occur, low level instability should rapidly increase, and good directional shear in the lower levels would allow for storm rotation. Clearing in eastern Iowa and northwest Illinois would be very pertinent to that situation. Ample surface heating would allow for rapid low level stretching of updrafts under the cold upper low which could aid in cold core tornado production.

These thoughts are likely all over the place. To sum up, I'm looking at two areas. The first, the most conditional of the two is southeast Iowa very early in the day. The second more likely target is going to be somewhere in central Illinois by around 2 PM near Interstate 72. I don't for see a big tornado event, but a lot of clear skies could convince me otherwise. You know, Galesburg to Peoria really has my attention. I'll stop now.

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