The Chicagoland area awoke to multiple warnings of severe weather and possible tornadoes Sunday.
The National Weather Service issued high wind warnings in northeastern Illinois -- including Cook, DuPage, Ford, Grundy, Iroquois, Kankakee, Kendall, La Salle, Livingston and Will counties -- until about 8 p.m. Sunday.
"We're very concerned," weather service meteorologist Gino Izzi told the Tribune earlier. "We're definitely stressing that this is not your run-of-the-mill tornado watch."
Izzi called Sunday's watch the "top tier" of tornado watches that ever gets issued, noting such a thing in the area is "extraordinarily rare."
The NWS forecast wind gusts of up to 60 mph that it said had potential to "blow down tree limbs and power lines, and could cause minor structural damage to buildings."
A key element in Sunday's severe weather is the unseasonably warm air, with temperatures in the 60s. Hail was predicted for parts of the area, causing Chicago's Office of Emergency Management & Communications to keep an especially close eye on the afternoon Bears game against the Baltimore Ravens at Soldier Field.
"We've been in contact with the Bears," said OEMC spokeswoman Melissa Stratton. "We will continue to monitor the weather and will work with the Bears and Soldier Field (staff) to ensure the safety of the attendees of today's game, should weather become an issue."
OEMC and Soldier Field staff say they have an evacuation plan in place should severe weather hit during game time.
According to AccuWeather, other Midwestern areas were at risk for tornadoes as well, ranging from Davenport, Iowa to Detroit.
CHICAGO (AP) — A number of Midwestern states woke up Sunday to the threat of intense thunderstorms and even tornadoes, with officials raising concerns that people — including fans heading to some NFL games — might be caught off guard by such severe weather at this time of year.
"People can fall into complacency because they don't see severe weather and tornadoes, but we do stress that they should keep a vigilant eye on the weather and have a means to hear a tornado warning because things can change very quickly," said Matt Friedlein, a meteorologist with the National Weather Service.
According to agency officials, parts of Illinois, Indiana, southern Michigan and western Ohio are at the greatest risk of seeing tornadoes, large hail and damaging winds throughout the day Sunday. Strong winds and atmospheric instability were expected to sweep across the central Plaines during the day before pushing into the mid-Atlantic states and northeast by evening. Many of the storms were expected to become supercells, with the potential to produce tornadoes, large hail and destructive winds.
In Chicago, the Office of Emergency Management and Communications issued a warning to fans attending making their way to Soldier Field to watch the Chicago Bears host the Baltimore Ravens. It urged fans "to take extra precautions and ... appropriate measures to ensure their personal safety."
Friedlein said that such strong storms are rare this late in the year because there usually isn't enough heat from the sun to sustain the thunderstorms. But he said temperatures Sunday are expected to reach into the 60s and 70s, which he said is warm enough to help produce severe weather when it is coupled with winds, which are typically stronger this time of year than in the summer.
"You don't need temperatures in the 80s and 90s to produce severe weather (because) the strong winds compensate for the lack of heating," he said. "That sets the stage for what we call wind shear, which may produce tornadoes."
He also said that the tornadoes this time a year happen more often than people might realize, pointing to a twister that hit the Rockford, Ill., area in November 2010.
Friedlein said that the storm will move across northern Illinois from 10 a.m. to 4 p.m., meaning Chicago could see the brunt of it about the time the Bears-Ravens gets underway.
NFL games in Cincinnati and Pittsburgh also could be affected by the rough weather.