Tuesday, July 08, 2008

Will the storms up north get stronger?

One of the first things I look at when I come into work is the radar. Sure enough we've got a few storms firing right along the cold front from northeast Iowa up to Appleton, Wisconsin. One of our bloggers, Justin, mentioned "what will happen to these?" Well Justin, we have to look at the energy the atmosphere holds. The graphic on the left is the CAPE or convective available potential energy. Values above 1500 are needed to sustained surface-based storms...and in turn severe weather. Another thing we can look at closely is the LI (or lifted index). The farther these numbers are below zero the more unstable the atmosphere is. Certainly a big -5 isopleth in southern Wisconsin is unstable enough. If those were the only two variables though. I'm also looking at moisture convergence, freezing levels (which would produce hail) and wind shear. These factors aren't quite as impressive as the CAPE and LI's right now.

One thing we'll have to do over the next 1/2 hour to hour is monitor the progress of the line of storms. Should they increase it tells us they are utilizing the instability. If they remain steady-state, there's a variable missing. Time to wait and see. Great question!

3 comments:

Justin said...

Thanks!

Garrett said...

Just checking to make sure they do officially start keeping track of the daily records right at midnight and not sometime the following morning. Because there is no way that anywhere around here only got .01 of an inch of rain with the rain that came down between the 12 and 1 time period this morning. Ha then again thats our stupid airport for ya.

tony said...

actually garrett, there was a super heavy downpour that came through a little after 1:30 pm. At our walmart that is. It was bad.