Arctic Outbreak to Bring Coldest Air of Season; Subzero Temperatures Possible

By Linda Lam
Published: November 9,2014



 
The calendar may only say November, but a mid-winter preview is looming this week. Arctic air has begun spilling into the north-central U.S., and it will bring the coldest air by far of this young fall-winter season to much of the central and eastern U.S.
(MORE: Expert Analysis | Winter Storm Central)
The cold this time will last longer and will be more widespread than other cold surges we have seen so far this season. By the end of the week, more than two-thirds of the U.S. will see below-average temperatures, and some areas could drop below zero during this cold snap.
The cold front has already begun its plunge. Colder temperatures arrived in Montana and the Dakotas late Sunday and will spread across more of the Plains Monday. Wolf Creek, Montana, fell from 49 degrees to 27 degrees in just one hour Sunday afternoon, according to Weather Underground data.
(FORECAST HIGHS: Mon. | Tue. | Wed. | Thu. | Fri.)
Accompanying the front will be a ripple of low pressure leading to widespread snowfall across the north-central states. The Weather Channel has declared this the first named winter storm of the 2014-15 season.
(FORECAST: Winter Storm Astro)
Highs 10 to 35 degrees below average will plunge into the Plains, western Great Lakes, Upper and mid-Mississippi Valleys on Monday and Tuesday. Minneapolis will see its first sub-freezing high temperatures of the season this week. In fact, temperatures may struggle to top the freezing mark in the Twin Cities for more than a week.
Rapid City, South Dakota, will go from a high in the lower 50s on Sunday to a high in the 20s on Monday.
Chicago may also see highs near or slightly below freezing through this week and into early next week. The last time Chicago had a daytime high that didn't rise above freezing was March 25.
It will be breezy as well, which will make it feel even colder. Wind chills will range from the single digits below zero to the teens for much of the northern Plains and Midwest, especially midweek.
A few record-cold high temperatures are possible as well, particularly in Indianapolis on Wednesday (current record is 33 set in 1996) and Chicago next Saturday (current record is 32 set in 1969).
The coldest temperatures -- the heart of the cold air -- will be anchored in the northern Plains and Midwest, but it will stretch across much of the central and eastern U.S. High temperatures will only be in the teens for much of the northern Rockies and northern Plains for several days, especially Tuesday and Wednesday. Highs in the 20s and 30s will dominate the rest of the Plains and Upper Midwest.
Single-digit lows will become widespread this week. One of the first places to get that cold was near Glacier National Park in Montana, where the Logan Pass Visitors Center dropped to 9 degrees just before 5 p.m. Sunday.
Single-digit lows will become more widespread in the northern Rockies and northern Plains beginning Tuesday morning, and will eventually spread east across much of the Upper Midwest during the week. Lows in the single digits below zero -- and even a few double-digits below zero -- are likely in parts of Montana, Wyoming and the western Dakotas by Wednesday and Thursday mornings, and may show up as far east as the Twin Cities by next weekend.
Areas that receive significant snowfall from Winter Storm Astro may see temperatures fall even lower if clear, calm conditions develop on any given night.
(FORECAST LOWS: Mon. | Tue. | Wed. | Thu. | Fri.) 
The cold front is expected to reach the Northeast by Thursday, with the brunt of the cold first being felt by Friday. High temperatures won't likely top 50 degrees Thursday in Washington, D.C. The last time that happened was on March 26. New York City may see its first freeze sometime late this week and Boston may also drop to 32 degrees, which last occurred on April 18.
The cold will also plunge into parts of the South. Nashville will see highs only in the 40s starting Wednesday, and daytime highs in Atlanta may struggle to reach 50 degrees for several days starting late in the week. Dallas will see high temperatures only in the 40s for several days next week. The last time Dallas did not reach 50 degrees was back on March 3.
Temperatures will remain below average for the central and eastern U.S. at least through the end of the week.
In addition to Winter Storm Astro, some lake-effect snow is also expected to develop by midweek as the cold air locks in across the Great Lakes.
The large expanse of cold air will allow any storm systems crossing the country to bring the potential for wintry weather:
- One area of low pressure could bring a rain/snow mix to parts of the Mid-Atlantic and Northeast late in the week. Snow, if any, should be light.
- A second system could bring snow and ice much farther south late in the week, possibly bringing winter driving conditions to Kansas, Missouri, and even Oklahoma by the weekend of Nov. 15-16. It's not out of the question that this could bring wintry weather to the East Coast states by early next week, but it's too early to be confident in any details.