A Severe Thunderstorm Watch was issued for several parts of the region until midnight Tuesday.
The National Weather Service also issued a Tornado Warning and Severe Thunderstorm Warning for several counties in the Tri-State on Monday.
The NWS radar indicated a line of severe thunderstorms that were capable of producing quarter size hail and damaging wind up to 70 mph. Law enforcement reported numerous trees down in Boon County with this line of storms.
Around 7 p.m. Monday emergency sirens sounded in Liberty Township in Butler County. The Lakota school board meeting was suspended for at least a half an hour as people watched the threatening clouds overhead.
Many who stepped out of the meeting observed the cloud mass just south of Princeton Road to be rotating as it moved eastward. However, only straight-line winds were felt as the clouds passed overhead. Extremely high winds and rain immediately followed the storm.
Power was knocked-out for tens of thousands of people around the Tri-State. At one point almost 90,000 people were without power.
In Hamilton County Fairfax police had a cruiser with emergency lights sitting in the intersection of Wooster Pike and US 50 to alert drivers to the intersection. A Duke power truck also drove around Fairfax with a bright search light shining into the trees looking for a downed power line.
Downed trees continue to hamper Tri-State roads. One tree reportedly fell on Reid Avenue in College Hill and another blocked a point of State Route 743 near State Route 222 in the Point Isabel are of Clermont County.
For information on what to do in the event of a tornado click here http://www.wcpo.com/dpp/weather/tornado_alley/what-to-do%2C-where-to-go-in-a-tornado1276647702021 .
To see the latest in power outages across the Tri-State visit http://www.duke-energy.com/ohio/outages/current.asp .
For information on National Weather Service terms visit http://www.weather.gov/glossary/ .