Wednesday, June 27, 2012

Slight Risk of Severe Weather Tomorrow

There is a slight risk of severe weather tomorrow over northern Illinois and eastern Iowa as a cold front moves in to ward off unusually hot temperatures for that region of the country.

Instability is forecast to be on the high end, not surprising for 100 degree heat. The Storm Prediction Center does mention the potential for 4000-5000 j/kg of instability, which is indeed very high. The NAM indicates a small area of enhanced rotation potential over northern Illinois, slanted more towards the area south of Chicago, IL going into extreme northwest Indiana. Over the general lower Great Lakes region, there could be a widespread weak capping inversion, which would likely be crushed by at least 3000 j/kg of instability currently being projected by the NAM.
The GFS is bullish on instability, placing over 5000 j/kg of potential energy over northern Illinois, whereas the NAM centers the instability into the Upper Midwest. Additionally, the GFS disintegrates capping potential in Northern Illinois, opting to place any inversion to the south of a line roughly following Interstate 80. There looks to be some shearing in southern Wisconsin and areas west, igniting potentials for some supercellular structures of which the Storm Prediction Center does find plausible. Precipitation values off the GFS at roughly 7:00 PM CDT tomorrow do indicate what could be a small cluster of storms, or an area of cells in northern Illinois. These could reach severe limits and will have to be watched in future forecasts.

Andrew

7 comments:

Svr Expert said...

Lots of tstms are likely for the next few weeks stretching along and near I-80.

ERN WX said...

Hello, Andrew. I have a link to the SREF that the SPC uses. I didn't see it on your models page so I thought I'd give it to you. spc.noaa.gov/exper/sref. It is the one I use a lot; except for it is free and available to the public. It is very helpful in predicting svr, snow, and flooding. I hope that it is of some help if you don't already have it. SREF has been exceptional lately.

Tstm said...

Lots of svr is on its way. It is almost July, so it would be best to make things exciting for a while!!!!!!!

Anonymous said...

Summer is so nice when it is dangerous. Sarcastic. I don't mind the storms, though.

Andrew said...

ERN WX: I actually already have that up on the SREF page, but yes, that is a great model ensemble set to use. A very helpful set, especially in the winter with low placement.

ERN WX said...

Okay, that is great!!!!!!!!! It is such a valuable model. I have been basing my short range forecasts primarily on it for the past month, since it has done so well. I normally use it for forecasting snow totals. Normally it is within 2 inches. It gives your area an elevated supercell potential, tomorrow. SPC is thinking the same. I'm in see text for day3. Hope you get good storms and stay safe!!!!!!!!!!!! A derecho sounds nice.; Chicago gets them about every year. I haven't seen on in ages. Multicell clusters are always favored here. A few sprcls though.

ERN WX said...

Edit. Forgot about downgrade. SREF strongly disagrees with them. Some days I have doubts about them. Yes, capping is a serious issue, but their willl be strong tstms. Poss svr. Storms will break the cap.