T-Storm & Severe Weather Chances

***Watch WISN 12 News for the latest weather information!***

Thank you for stopping by the Weather Watch 12 blog!  For the first time in weeks the 7 day forecast looks more like spring than winter….with no snow, and some temperatures around or above 60 degrees in the forecast.

As temperatures warm this time of year storm systems are more likely to produce thunderstorms in our area.  While severe weather is possible anytime of year, it is much more likely in the spring and summer here in Wisconsin.  We are entering severe weather season, and it does look like some severe weather is possible close to home over the next 10 days.

The first opportunity will arrive late Sunday.  Let’s take a look at this storm system.  Low pressure will push into the Midwest on Sunday.  As a warm front nears the area a band of showers will be possible Sunday morning, then a break from midday into the afternoon. 

As the low approaches late in the day it may trigger another round of showers and t-storms.  Just how far north the warm front lifts will be key, because thunderstorms thrive off moisture and warm temperatures.  Below is the surface map forecast from the HPC.  This map is valid at 7pm Sunday.  Notice the warm front near the Wisconsin-Illinois border. 

With the warm front sitting so close to our viewing area, there will be a big temperature spread over a relatively small area.  Winds will be southeast for much of the day in Milwaukee, meaning the cooler air over Lake Michigan will spread over lakeshore locations keeping them cooler.  While inland areas should easily warm into the 50s.  Below is ONE temperature FORECAST and it is from the RPM model.

This map is valid at 3pm Sunday.  Notice the huge spread of temperatures.  The RPM is one of the warmer solutions with this storm system…so these readings may be a touch too warm, but I do think Madison reaches the 60s on Sunday. 

As the main are of low pressure nears southeast Wisconsin Sunday evening thunderstorms will begin to develop.  The big question is how quickly will the line of storm form?  If the storms form over south central Wisconsin there may be a chance of strong storms in our part of the state.  But if the storms fire over Milwaukee or far southeast Wisconsin, I think they would be out of our area before they become severe.

Here is what the Storm Prediction Center is saying about severe weather chances.  The map below is the Day 2 convective outlook.  The green circle indicates areas that have a ‘slight risk’ of seeing severe weather.  Keep in mind to be considered severe a thunderstorm must produce or have the radar indicate one of the following: 1″ diameter hail, 58 mph winds or greater, or a tornado.

The slight risk area below hugs the WI/IL border. 

The RPM, which is our high resolution computer model organizes the strong storms just south of Wisconsin Sunday evening.  The map below is valid at 9pm Sunday evening.  The storms are firing along a cold front and close to low pressure.  The blue color represents snow, at least we won’t see that!

Right now I’m leaning that the storms form over our area and quickly move southeast, and that our chance of seeing severe weather Sunday evening is low.  The focus this time will be more over Illinois, Indiana and southern Michigan.  This is something we will continue to monitor as any shift north, even 10-50 miles may bring the strong storms into our area.

With the cold front blowing through Sunday Night, that means some good news for Brewers fans on Monday.  Any rain showers should end before 9am, but it will be chilly with temperatures in the 40s and winds gusting to 30mph!

Watch WISN 12 News for the updates and please post your thoughts and questions in the comments section of the blog.

Have a great day!

Jeremy Nelson