Coldest Blast in Years Heading for Midwest, Great Lakes

Midwesterners are in for a dangerous round of bitterly cold air and extreme wind chills as January draws to a close. Temperatures are expected to bottom out from Tuesday to Thursday, hitting their coldest levels in several years in parts of the Midwest and Great Lakes. Less-extreme but still-noteworthy cold will overspread much of the nation east of the Misssissippi by midweek.

This Arctic outbreak—well advertised in long-range weather models—is in line with seasonal forecasts issued as far back as November by The Weather Company. As we discussed in a post on January 18, the outlooks gave increasingly high odds to unusually cold weather in the eastern United States toward the latter half of this winter.

The culprit behind next week’s cold blast is a lobe of the stratospheric polar vortex predicted to set up shop across the Great Lakes, far south of its usual position. The extremely cold upper-level low will pull a frigid dome of surface high pressure from central Canada into the central and eastern U.S. as the week unfolds. On Friday, ahead of the main event, temperatures fell below zero as far south as northern Missouri, with wind chills dipping below –20°F as far south as Iowa, reported weather.com.

...

A long stretch of below-zero cold

The largest number of records next week will likely be for cold daily highs, according to an NWS tool that compares temperatures in the National Digital Forecast Database against existing records.

...

Current forecasts have Chicago struggling to reach 0°F on both Wednesday and Thursday. This is an unusually long period of time for Chicago to stay below zero. To put some perspective on this potential cold, only eight times since 1872 has Chicago recorded sub-zero highs on at least two consecutive days, the most recent being early February 1996.