The calendar said July 1st, but if you went outside on Wednesday, you might have thought it was October.
Thick cloud cover and cool northwest breezes remained in place on Wednesday, contributing to temperatures remaining only in the lower to middle 60s. The high temperature only reached 63o in Madison and 64o in Milwaukee. The high of 63o in Madison is a new record for July 1st, and is the 6th coolest Maximum temperature for the month of July (records at Madison go back to 1850).
Here are the daily and monthly record low Maximum temperatures for both locations:
July 1st record July Monthly record
low Max Temp low Max Temp
Milwaukee 62 in 1986, 1876 57 on July 2nd, 1982
Madison 63 in 2009 (previously 64 in 1959) 60 on July 4th, 1967 and July 22nd, 1992
The reason it's been so cool lately is the presence of an upper level low over the northeastern Great Lakes and southern Ontario. This persistent upper level low has funnelled unseasonably cool air south on the backside of the circulation into the Western Great Lakes. The cold air in place, combined with cloud cover all day Wednesday kept temperatures well below seasonal normals.
Below is a graphic depicting the weather setup over the region earlier on Wednesday (click for a larger version):
The upper level low pressure area will continue to weaken today (Thursday), and tonight, and move off to the east into southeastern Canada by Friday. This will allow at least partial sunshine to return to the region today and Friday, and will result in warmer temperatures returning to southern Wisconsin.
Jeff Craven, Science and Operations Officer
Penny Zabel, Meteorologist
Alex Lamers, SCEP
Marc Kavinsky, Senior Meteorologist
NWS Milwaukee/Sullivan WI