Sunday, July 1, 2012

Afternoon Discussion on Severe Weather Potential

The Weather Centre
Afternoon Discussion
2:41 PM CDT July 1, 2012

Mesoscale Convective System (MCS) is currently moving across central Indiana, producing severe thunderstorm warnings of 60 MPH winds and quarter size hail. Forecast issues involve track of MCS and potential development of second MCS in southern Wisconsin.

Latest RAP model guidance takes Indiana cluster through the Ohio Valley area, where it supposedly splits off into several separate cells and weakens in the process. I have trouble believing that scenario, considering there is widespread 2000+ j/kg of instability ahead of it, and will discard that solution. However, initialization of RAP is correct, and I will use that for guidance on the potential second MCS development in southern Wisconsin.
17z RAP does develop a second convective cluster in southern Wisconsin, which has been trending within the model for several runs now. The MCS is then forecasted to shift southeast through the evening hours before hitting the northeast Illinois area, which already underwent a severe weather event today. RAP is insistent on that cluster then also slamming northwest Indiana, which went through the same severe weather that Chicago dealt with earlier today.
Just to see what would happen, I did run the RAP-devel model, which showed a weaker cluster of showers and storms hitting the areas mentioned above. I do not think that is a bad idea, considering fair stability has taken over following the strong thunderstorms that swept through northeast Illinois and likely high temperatures below what was being forecasted.
I do think that 15z HRRR is a good middle ground, where a small MCS sweeps into northeast Illinois and dies out into northwest Indiana. However, it will eventually depend on the available instability and high temperatures of the day.



mike paulocsak said...

Hello Andrew!I checked weather underground radar.It looks like some of the areas that had severe weather Friday,will have to deal with it again.Let's hope it's not too bad.I'll keep you updated on damage reports if any do happen to occur since i'm from Ohio.Thanks.

mike paulocsak said...

Hello Andrew.A storm near cedar point in Ohio had a funnel cloud.As to my knowledge,no touchdown.

ERN WX said...

Hello, ANdrew and Mike. Here are a few storm reports which sadly aren't from me 1.00 in hail to my N and another 1in to my S.