A very chilly weather pattern will continue for much of the Northern Tier of the country this April. The Polar Vortex will be sitting over southeastern Canada this entire week, and pieces of this vortex spinning around the main circulation will swing through parts of the country, bringing rounds of air with temperatures as much as 40 degrees below average at times.
The cold is being felt this morning. In fact, the combination of the Arctic air combined with a light snow pack allowed for the temperature to drop down to -1 degrees in Lincoln, Illinois. Yes, -1 degrees in April in Illinois. That is unprecedented. The previous daily record low was 20 degrees for the city and the all-time low temperature for the month of April was broken at 17 degrees. The last time this city dropped below zero at any time of the year was over 20 years ago on March 12, 1998.
This Monday, high temperatures across much of the Northern Plains and Upper Midwest will only be in the teens, 20s, and 30s, which is up to 40 degrees below average. Wind chills of 40 degrees or lower will reach as far south as north-central Texas through portions of the Tennessee Valley. Below average temperatures of generally 5 to 15 degrees below normal will also expand into the Great Lakes region and Northeast.
On Tuesday, wind chills will be below zero when you wake up in portions of the Dakotas, northern Minnesota, and the northern Rocky Mountains. Freezing temperatures will work as far south as the Texas Panhandle and central Oklahoma. During the day, temperatures will be as much as 20 to 35 degrees below average Northern and Central Plains as well as the Northeast while the Northeast experiences temperatures of 5 to 15 degrees below normal. The rest of the country will be warmer than normal with highs up to 25 degrees above average in the Ohio Valley ahead of a cold front, which will fuel severe storms.
On Wednesday, the warmth air will move into the East Coast while colder air works farther south and east. While the East Coast is experiencing temperatures up to 30 degrees above average, the Central US will be feeling temperatures up to 30 degrees below average. This includes the Great Plains, Midwest, and most of the Southeast and Gulf Coast. Sub-20 degree wind chills Wednesday morning also reach as far south as the Mid-Mississippi River Valley back through the Texas Panhandle.
A reinforcing shot associated with a new piece of the Polar Vortex over Canada will begin to eject into the United States on Thursday. The worst of the cold will be in the interior Northwest and Northern Plains where highs will be up to 30 degrees below average. Otherwise, most locations east of the Rockies, with the exception of the Southern Plains, will be 5 to 20 degrees below normal.
Now the barney colors that you see on the cold weather maps will begin to show up on Friday as this piece of the Polar Vortex intrudes more of the country. High temperatures will be 20 to 35 degrees below average for Northern and Central Plains, Midwest, and Great Lakes region. The colder air will extend as far east as the Mid-Atlantic and Northeast and as far south as the Tennessee Valley. Texas and Florida will be the only hot spots east of the Rockies.
Conditions will begin to improve somewhat this weekend. Wind chills will still be below zero Saturday morning, however, from northern New England through the Upper Midwest for many towns. During the daylight hours of Saturday, temperatures will rise into 30s, 40s, and 50s for most locations in the Northern Tier. That is generally 10 to 20 degrees below average. Those below average temperatures, however, may extend as far south as the central Gulf Coast.
Temperatures will recover on Sunday lightly as warmer air intrudes into the Southern Plains and Gulf Coast. The warmest temperatures relative to normal will be in Texas, which is where highs will be up to 25 degrees above average. Meanwhile from the Northern Plains through the Northeast and Mid-Atlantic, most will be experiencing temperatures between 5 and 15 degrees below average.
Based on the long-range outlook, this dominant cold pattern will persist through mid-next week, before we turn into a more seasonable pattern with rounds of warm and cold. Those periods of cold won’t be nearly as cold as this weeks’.