Iowans woke up to a feeling of fall again this (Tuesday) morning, and forecaster David Sheets says we can expect more. It’s true that fall and winter will approach from the north. Sheets says actually it works more northwest-to-southeast. He says they’ve already had temperatures in the thirties up in northwestern Iowa.
There’s a difference in elevation, about a thousand feet across the state, and he says that’s a reason why Canadian storms enter the state and then stall there for a while before proceeding. That’s part of the reason why he says northwest Iowa is a little cooler on average. And Sheets says it means different dates for the average start of seasons like autumn.
In the spring, he adds, the warmer air masses “punch into southern Iowa before they get up north.” While noisy thunderstorms heralded the abrupt change from eighties to cooler weather over the weekend, the meteorologist says we’ve seen the last stormy weather for a few days.
The past weekend’s storm system is leaving, he says, and high pressure that followed it is what’s bringing us the cool weather this week. In a few more days a strong system heading this way from the western part of the country could bring more storms for the coming weekend. Sheets, who works in the Quad Cities office of the national Weather Service, says the average date for the first measurable snowfall in Iowa is mid to late October.