9:15AM TUES - Models show a low pressure system strengthening over Wisconsin today through Wednesday. Main hazards include heavy rain potential across northwest Wisconsin. With dry conditions recently I view this as a positive impact. We could use the rain. The other issue is the potential for strong or severe storms south.
HEAVY RAIN
I went with a broad 0.5-1.0" zone across northern and portions of central WI. I opted for a bullseye approach to northwest WI of 1.0-1.5" as model agreement is pretty good for that. NAM models are a little wetter and tempting as it is; played the conservative EC solution. As already mentioned; rain is a good thing right now because April has been relative dry.
SEVERE THREAT SOUTH?
Models have consistently shown a broken line of thunderstorms moving east across southwest Wisconsin for this afternoon & evening. However they have been inconsistent in severity. The 00Z and 06Z runs this morning were too aggressive compared to what they've been showing. Quick look at the 12Z NAM casts doubt on those previous runs, suggesting only a minor threat. The 00 HREF cams were rather weak too. So here's my prediction.
1. Wisconsin could see a few strong or even severe cells during the late afternoon. Large hail will be the primary threat.
2. The main activity will be across SE IA or W IL, well south of Wisconsin. I believe this will obstruct the moisture influx into the region which was iffy to begin with.
3. Rain/convection currently located west of the Mississippi River will move through the target area this morning...helps moisten the boundary layer YES but could also become a focus for development in IL during the mid day.
So there are many issues and reasons to think this setup may not come together just right. I will be monitoring the situation throughout the day.