As spring and early summer roll in, they are often joined by some unwelcome company.
Governor Scott Walker has declared this week — April 17-21 — as Wisconsin's Tornado & Severe Weather Awareness Week.
As such, statewide tornado drills will be held Thursday, April 20 with the goal of making sure residents, schools and businesses throughout Wisconsin have made the necessary preparations should the weather turn ugly in the near future.
In the city and town of Brookfield, sirens will be sounded as part of Thursday's statewide drill. Both communities also test the sirens on a regular basis.
"We have six sirens," town of Brookfield Administrator Tom Hagie said.
The system is tested by the county once per month between Labor Day and Memorial Day and once per week between Memorial Day and Labor Day.
The city of Brookfield also puts its 13 tornado sirens to the test multiple times per month. Director of Finance Robert Scott serves as the Emergency Management Director for the community.
"We test on the first and third Thursdays of every month," Scott said. "The first Thursday is where you'd hear the sirens go off for an extended period of time. The second test is generally silent."
A statewide tornado watch will be issued at 1 p.m. Thursday and will be followed by a mock tornado warning at 1:45 p.m.
A second tornado warning drill will be issued at 6:45 p.m. to allow those who were busy during the day to test their emergency preparedness.
According to the National Weather Service, there were 16 tornadoes in Wisconsin last year — slightly below the annual average of 23.
The strength of tornadoes is measured by the Enhanced Fujita scale, which ranges from EF-0 to EF-5.
"All of the tornadoes were either an EF-0 or EF-1," the NWS said in a press release. "However, it's not a question of if we will have a violent storm, it's a matter of when."
EF-0 and EF-1 tornadoes have three-second gust speeds of 65 to 85 mph and 86 to 110 mph, respectively. An EF-5 is the most intense category of tornadoes with gust speeds of over 200 mph.
If real severe weather is expected in Wisconsin Thursday, the drills may be postponed until Friday at the same times; however, if severe weather again presents itself that day, the drills will be cancelled.