11/22/10 NOW: IA/MO/IL

[Mark Sefried]

MCD out attm for Eastern IA, Northeastern MO, and Western IL for a watch box. SPC Mesoscale Analysis page showing parameters sufficent for low topped supercells and a few possible tornadoes especially for areas over far NE MO into West Central/North Central IL. Effective SRH helicity of 500-600 m/s, cape between 500-1000 j/kg, li's near -4, plenty of clearing, and strong southerly winds along with dew points near 60 is occuring throughout the area. TCU is going up along the front front from Eastern Iowa SW through West Central MO Rapidly . Of special interest is the TCU that is developing out ahead of the front over NE Missouri attm and will be moving into Western/North Central IL shortly. Looks to be a surprise little event shaping up attm and I would not be surprised to see a tornado or 2. Areas from near Monmounth, IL NE into North Central IL need to be watched closely.

 

[Jeff Duda]

Tornado watch has now been issued for the previous MD mentioned by Mark. Looking at the current parameters, I see no reason why some of these storms should not go tornadic. Everything is sufficient, and by looking at radar trends, a few discrete storms are really intensifying, especially near Keokuk/Ft. Madison, IA and farther SW into NE MO. There's 60 kts or better effective shear, > 35 kts 0-1 km shear, effective SRH > 400 m2/s2 in the area these storms are moving into with a large area of > 300 m2/s2 surrounding it. Couple that with sufficiently low LCLs and 0-3 km CAPE > 100 J/kg in the area, and I reiterate: there should be no reason some of these storms should not go tornadic.

ADD: right as I was posting this, the Ft. Madison storm went SVR warned and already shows a TBSS from 0.5 deg. to 1.9 deg. from KDVN. Not to mention it is showing some decent broad rotation now.

 

[ahaberlie]

Take a look at the cell near Monmouth, Il.. it is starting to get organized ahead of the initial line.

 

[Chip Redmond]

Storms really starting to organize. Several discrete cells that have had persistent couplets heading towards the Chicago area.

 

[Jeff Duda]

Same two storms I mentioned in my prior post are still alive and kicking. They went through a lull in activity but have certainly reintensified now. Big tornado warning covering both of them. One has a double-hook structure on BR. There isn't quite as much CAPE or shear as there was before noon, but still enough for supercellular and tornadic activity in N IL. The Chicagoland area will need to be on the lookout within a few hours because these two storms are headed straight for the metro area.

 

[Rob Gardner]

Was on the tornado warned cell, rotation passed by slightly rain wrapped and very disorganized. It could have weakened since the initial warning was issued. Temps in the upper 50s on the back end of the storm and no sign of hail or wavy wind damage. Anything these storms produce look to extremely short lived and now that they are going more linear the tornado threat is likely over

 

[rdale]

I don't see the tornado threat done at all, major damage reported on the WI/IL line and that cell is in a good area. Also the storms west of Chicago are holding their own and moving into a good area of TORH.

 

[Rob Gardner]

The northern most cells do appear to be sustaining, I should have been more specific to the central Illinois area. Temps are down to the upper 50s here and most of the cells have gone linear. We did manage to get on the leading edge of the line and experience 50mph or so winds but for everything south of the warm front it looks like the show is over

 

[melissa wheat]

The northern most cells do appear to be sustaining, I should have been more specific to the central Illinois area. Temps are down to the upper 50s here and most of the cells have gone linear. We did manage to get on the leading edge of the line and experience 50mph or so winds but for everything south of the warm front it looks like the show is over

Its 66 here in springfield and it looks like we still have some strong storms headin towards us from the southwest.

 

[rdale]

Melissa - conditions are much better to your north with that initial line of thundershowers over you really killing the threat. Chicago/Milwaukee still in the zone. (Rob - add your location to your profile, it might help.)

 

[Rob Gardner]

Impressive cell in south west Missouri now tornado warned. That cell
Could be long lived and stay discrete for a while. I'm at a little but of a loss for why they extended a tornado watch into east central Illinois, South west and southern Missouri look like the best bets for storm development and I can't see how any instability could be left north of I-70....