So far temperatures during the winter of 2018-2019 have been extremely tame and above normal.  Snowfall is way below normal since the start of December.  Milwaukee has only recorded 1.7" of snow.  That's close to 16" below normal.  

Snow is expected to arrive late Friday and into Saturday.  There could be a swath of 2" to 5" of snow out of this next system; however, it's the blast of cold air behind it that will make it significant.

The brunt of the cold will be felt on Sunday and Monday.  Highs will only climb into the teens with lows in the single digits.  The coldest Milwaukee has been this season has been 24 with a low of 14.  The last time Milwaukee recorded a single digit low was 337 days ago on February 9th.