What is a pneumonia front?
The weather event is exclusive to one part of the Midwest and can make it feel like the seasons have changed in a matter of minutes.
Storm clouds hang over the downtown Chicago skyline Monday, June 30, 2014, as rain and high winds move into Illinois from Iowa. Flights were canceled at Chicago's O'Hare International Airport as northern Illinois braced for severe weather. (AP Photo/Kiichiro Sato)
Cold fronts move through most of the United States on a regular basis, but there is one specific type of cold front that is unlike many others that sweep across the country, and it has a unique name as well.
A pneumonia front is a localism originating from the midwestern U.S. that describes when cold air over Lake Michigan rushes inland, causing temperatures to drop dramatically. The rapid decline in temperature can also be accompanied by clouds and rain showers.
Temperature
While it sounds like another viral term like bomb cyclone or supermoon, which have been used on social media in recent years, the phrase pneumonia front has been used by meteorologists in the Midwest for decades.
In late spring, a pneumonia front can quickly transform the weather from warm and sunny to damp and chilly in less than an hour. In extreme cases, the mercury could plummet more than 20 degrees in a matter of minutes. Since the event is related to Lake Michigan, this specific type of cold front can only happen in Wisconsin, Illinois, Indiana and Michigan.
GET THE FREE ACCUWEATHER APP
•Have the app? Unlock AccuWeather Alerts™ with Premium+
A pneumonia front is making headlines in the Midwest this week, as one caused the temperature to plummet in Milwaukee, Wisconsin and Chicago.
After temperatures in Milwaukee topped out at 81 degrees Fahrenheit at 3 p.m. CDT Tuesday, the mercury plunged to 62 degrees by 3:28 p.m. CDT. Just before sunset, the temperature was down into the upper 40s with an AccuWeather RealFeel® Sun in the lower 40s.
The pneumonia front will have staying power in the Windy City. A high temperature in the mid-60s is forecast for Wednesday after temperatures there topped out around 80 degrees Tuesday.
Want next-level safety, ad-free? Unlock advanced, hyperlocal severe weather alerts when you subscribe to Premium+ on the AccuWeather app. AccuWeather Alerts™ are prompted by our expert meteorologists who monitor and analyze dangerous weather risks 24/7 to keep you and your family safer.
Report a Typo
