Warming Trend in the Forecast for Much of Eastern U.S.

The unseasonably cold December is being replaced by an unusually warm start to the month of January for the Midwest and the Northeast. Record-challenging temperatures are bearing down on millions of Americans for the first full week of the year. Here is a look at what to expect this week as warmth builds across much of the central and eastern U.S.

Warmer Temperatures Building Across the Midwest and Northeast

A major change in the weather pattern is on tap for this week across the Midwest and the Northeast. The warmer temperatures will feel like quite a shift from the last month of the year. A weakening of the polar vortex in December resulted in frequent surges of Arctic air throughout the central and eastern portions of the nation. The bitterly cold temperatures translated to higher-than-usual amounts of wintry precipitation as well as higher heating bills.

A strong polar vortex located near the North Pole tends to keep the coldest air in place over the Arctic Circle. However, the weakening of this strong vortex beginning in late November sent the Arctic air spilling to the south into Canada and the U.S. This vortex is now strengthening once again, pulling up warmer air from the south.

The change in the temperatures this week will be noticeable. For example, Chicago will land at about the 40-degree mark by Tuesday. The temperatures will continue to increase as the week progresses, peaking on Thursday with a forecast high of about 50 degrees. Unfortunately, the arrival of more clouds and rain will make it difficult to get outside and enjoy the warmer weather.