Pop Up Storm Up North Drops Temps 31 Degrees In Ten Minutes

A pop up thunderstorm, driven by northwest winds across a still cold Lake Michigan resulted in some wacky weather up north Tuesday.

This Early Heat Wave Can Make Things Weird In Michigan

A record setting early heat wave in Michigan got a little strange last night in Traverse City when a pop up thunderstorm brought a rapid temperature drop to the Cherry Capital.

The National Weather Service in Gaylord recorded a 31 degree drop in the temperature at Cherry Capital Airport Tuesday night. After a reaching a record setting high of 92 earlier Tuesday afternoon, the temperature had dropped a little to 88 degrees by 6:35pm, when northerly winds off of Lake Michigan, driven by pop up thunderstorms inland saw the temperature drop to 57 degrees in just ten minutes at 6:45pm.

Was It A 'Pneumonia Front'?

Some observers of the rapid drop said it could be something known in the northern Lake Michigan region called a 'pneumonia front'.

According to Wikipedia, a pneumonia front is defined as:

a rare meteorological phenomenon observed on the western shoreline of Lake Michigan during Spring and early Summer. These fronts are defined as lake-modified synoptic scalecold fronts that result in one-hour temperature drops of 16 °F (8.9 °C) or greater.

They do not necessarily have to be synoptic, or large scale, cold fronts. Pneumonia fronts are most common between the months of April to July when the temperature difference between the cold lake waters and the warmer air over land can be as much as 35–40 °F (19–22 °C). Under weak prevailing winds, a density current can often develop in the form of a lake breeze that moves from that water to the adjacent shoreline and several miles inland. This "lake-breeze cold front" can drop temperature in places like Chicago, Milwaukee, Benton Harbor, and Green Bay significantly as they cross the area.

I can attest to this effect, as I lived in Grand Haven for years, and it wouldn't take much of a breeze over the lake to drop temps quickly in the spring and fall.

A series of microburst thunderstorms hit across northern lower Michigan last night, from Glen Arbor on the northern tip of the Leelanau Peninsula to Interlochen, just south of Traverse City after the northerly winds dropped the temps.