Map showing projected temperature anomalies on Wednesday morning, with the cold air entrenched in the East and unusually mild air in the West. Image: Weatherbell.com
Record early cold air for early fall has enveloped a region from the Upper Midwest to the Gulf of Mexico, sending temperatures plunging to record lows.
The big picture: Freeze warnings are in effect for at least 46 million people, according to the National Weather Service. The cold will continue for several days.
Overnight lows are forecast to hit the freezing mark as far south as Georgia and Louisiana, and the unusually cold air has prompted warnings and advisories from Oklahoma to Virginia, including Gulf Coastal states. Freeze warnings include all of the states of Arkansas, Tennessee and Alabama, as well as large portions of other states. While the eastern half of the U.S. shivers, the West and much of western Canada are seeing unusually mild temperatures. Across the West, a northward bulge or “ridge” in the jet stream is sweeping north before plunging southward to the east. In Seattle, for example, the high temperature on Sunday reached 88 degrees, which set a record for the hottest reading for so late in the year. The heat contributed to fast-spreading wildfires that have spread hazardous smoke into the Seattle metro area, among other areas. By the numbers: Areas from the Midwest to the South and East Coast are now seeing temperatures between 15 and 30°F below average for this time of year through at least Wednesday.
Up to 18 inches of snow has fallen in northern Wisconsin and Michigan, where cold air blowing across the relatively mild waters of the Great Lakes are contributing to lake effect snow. Low temperatures in Atlanta on Wednesday and Thursday morning are forecast to be in the low-30s, with many areas reaching 32°F. The low temperatures in Birmingham and Selma, Ala. on Tuesday night are forecast to be just below freezing, at 31°F. Some readings in the upper 20s are forecast for northern Alabama. Temperatures in Houston have even dipped into the 40s overnight, which is more typically seen during the winter. Two records stand out: The thermometer reached 21°F in Des Moines on Tuesday morning, setting a daily record.
Omaha saw a record low of 16°F, which is the coldest on record for so early in the season since records began there in 1871. Yes, but: The cold weather in the Midwest and East is being offset by anomalously mild weather across much of western North America, extending into Canada and Alaska.
British Columbia and Alberta have seen July-like temperatures in the 70s early this week, while the Pacific Northwest continues to see temperatures between 10 to 20°F above average for this time of year, down a bit from this weekend. What’s next: The warm West, cold East weather pattern is forecast to reverse by this weekend, as the entire jet stream configuration changes. This would bring cooler, wetter weather to the Pacific Northwest, while the East enjoys a milder weekend.