A brief period of warm conditions will end as a strong cold front pushes through the Midwest and Northeast into midweek.
After an August-like weekend across the Midwest, temperatures will drop significantly to begin the new week.
The Northeast, however, will have temperatures rebound to between 10-15 degrees above-average Sunday into Monday before the same cold front pushes through on Tuesday.
According to AccuWeather Meteorologist Edward Vallee, "A strong low pressure system moving through Ontario will pump September-like warmth into much of the eastern U.S. early this week."
"This system will then drag a cold front through the Great Lakes on Monday and the Northeast on Tuesday, bringing a return to more typical October readings," he added.
While the majority of the precipitation will remain across Canada, some showers may move across portions of the Upper Midwest through Monday. A spotty shower may dot areas from the Ohio Valley to the Northeast Monday into Tuesday.
JUMP TO: Midwest Outlook| Northeast Outlook
Since the beginning of September, temperatures across much of the Midwest and Northeast have been running above normal. Despite a couple brief cool spells, temperature departures remain above normal.
Temperature departures are based on the average temperature on a given day compared to normal. For example, if the average temperature on a specific day is 58 F, and the normal average temperature is 51 F, then the temperature departure for that day was +7, or 7 degrees above normal.
Minneapolis, Pittsburgh, New York City and Ottawa could reach temperature departures near +5.0 F prior to the upcoming shot of cooler air.
Prior to the passage of the cold front late Sunday into Monday, a surge of warm air will build from the central Plains into Minnesota. Temperatures on Sunday will be more typical of August than October.
High temperatures reached the 90s across portions of the Plains on Saturday. Bismarck, North Dakota, reached 90 F on Saturday, falling short of the record high of 91 set in 1910.
Some record highs were broken or tied on Saturday across the Plains including Grand Forks, North Dakota; Mobridge and Rapid City, South Dakota; and Sidney, Nebraska.
Record-high temperatures will be challenged across portions of the region on Sunday including Minneapolis and Des Moines and Omaha, Nebraska.
As the cold front progresses through on Monday, high temperatures will drop as much as 20 degrees in some places in its wake. This drop in temperatures, however, will send temperatures to near-average readings.
High temperatures on Monday will range from the 50s from northern North Dakota to northern Wisconsin and the 60s from Michigan to South Dakota.
Windy conditions will accompany the cooler air as winds could occasionally gust over 40 mph. This will lead to very chilly AccuWeather RealFeel® temperatures.
Anyone heading out to Chicago to catch the playoff series between the Chicago Cubs and the St. Louis Cardinals on Monday and Tuesday should bring along a jacket.
High pressure will build into the central U.S. into midweek bringing brilliant sunshine, but temperatures will remain near-average.
Mild air will return across the Northeast through Monday. Temperatures into Monday will be more typical of September than October.
High temperatures will be in the 70s across the Northeast on Monday, around 5-10 degrees above normal.
As the cold front slices through on Tuesday, high temperatures will drop into the 60s behind the front. Areas near the Great Lakes may fail to reach 60 F.
Much of the Interstate-95 corridor from Boston to Washington, D.C., should reach the 70s before the cooler air builds in on Tuesday night, along with the chance for a passing shower.
Winds are not expected to be as strong behind the cold front across the Northeast compared to the Midwest.
Those heading to Citi Field to see games 3 and 4 of the National League Division Series between the New York Mets and the Los Angeles Dodgers on Monday and Tuesday night should bring along a jacket. Temperatures will hover in the 60s for the game on Monday night while a shower could dampen the area on Tuesday night.
Temperatures will continue to tumble for the second half of the week as the interior portions of the Northeast will not get out of the 50s.
A shot of cold air may invade the Midwest and Northeast next weekend. Should enough moisture be present, portions of the higher terrain across the Northeast may receive the first snowflakes of the season.