Tornado watches, warnings issued in Chicago area as storms ...

UPDATE: See the latest on what we know from these storms here.

Storms producing multiple tornadoes moved across the Chicago area Monday evening, sparking watches, warnings and dangerous conditions as many were urged to seek shelter immediately.

A "radar confirmed" tornado was reported near Sugar Grove and was moving into the Aurora area as of 9 p.m., according to the National Weather Service. Shortly after, another was confirmed near Oswego, moving east into Plainfield and southern Naperville.

Numerous other tornadoes were reported as storms continued.

"This storm is producing multiple tornadoes at the same time," the National Weather Service reported.

Chicago's O'Hare International Airport was under a ground stop as all departures headed for the airport were grounded "due to tornado" until at least 10:30 p.m. Trains on Metra's Union Pacific West and Northwest lines were halted "due to high wind warnings."

Thousands of power outages were also reported as of 9:45 p.m. across the area.

Just before the alert was issued, the National Weather Service warned a "complex of destructive storms" was moving into northwest Illinois.

"Have multiple ways to receive warnings tonight and be ready to seek shelter if one is issued for your area," the agency posted on X.

The Chicago area had already been upgraded to a moderate risk of severe weather as the threat for damaging storms heightened in the lead-up to the system's arrival.

The moderate risk is a level four out of five. Previously, the region had been under an "enhanced" risk, or a level three out of five.

"Severe thunderstorms are expected through this evening across portions of the Midwest, central High Plains, lower Great Lakes, and Arizona. The greatest potential for severe gusts is over eastern Iowa into Illinois and Indiana," the National Weather Service's Storm Prediction Center said in its update.

Wind speeds of up to 85 mph threatened the area, with widespread gusts in excess of 60 miles per hour in the forecast.

The NWS said strong to severe thunderstorms were expected to move into the area late Monday afternoon and continue into the evening.

"Damaging winds are expected to be the primary severe hazard, though isolated large hail and a few tornadoes will also be possible," the NWS said in an alert. "Torrential downpours may produce flash flooding."

"Tornadoes are likely along and near the apex of the developing bow," it added.

They were expected to dissipate overnight, NBC 5 Storm Team Meteorologist Alicia Roman said, coming to an end around 1 a.m. or 2 a.m.

A heat advisory was also in effect Monday, with "dangerous" heat and humidity levels expected, especially in counites to the west and southwest where the highest "feels-like" temperatures could reach between 105 and 100 degrees.

According to the NWS, the advisory was scheduled to expire at 7 p.m. Monday.