A shot of very cold air will head south across the Midwest by the end of the week.  This unseasonably cold batch of air will create some tricky frost and freeze issues throughout southeastern Wisconsin.

Friday morning looks like a possible frost, especially west of the lake.  The coldest morning is forecast to be Saturday.  High pressure aloft will send temperatures into the upper 20s and lower 30s.  A possible freeze is likely for the entire area.  Cover up sensitive plants you have already put in the ground. 

Freezing temperatures during the month of May are fairly rare in Milwaukee.  On average Milwaukee records one day with a low at or below 32.  In fact, it was 16 years ago when the last freezing temperature was recorded in May.  The record latest freezing temperature was May 27th!