One of the snowiest Halloweens in northern Illinois marks the end of a very wet October.
The weather station at Northern Illinois University measured 1.4 inches of snowfall on Thursday, making it the snowiest Halloween since 1895. David Changnon is the chair of NIU’s Department of Geographic and Atmospheric Sciences. He says October’s rainfall has been much higher than normal, and it’s much colder than expected.
“If you’re looking for a warm up to back into the upper 50s or 60s (the average high temperature now is maybe about 55-57), we’re not going to see that any time between now and mid-November,” he said.
He says some of the stronger rainstorms in September and October were caused by moisture coming from the tropics, by way of either California or the Gulf of Mexico. This moisture is distributed by strong atmospheric “dynamics.”
"You bring up more atmospheric moisture both at the surface and in the mid-atmosphere that then, as it’s lifted here above us, it creates more clouds, more precipitation," Changnon said.