Good evening, I'm Dion Cheney; Nicole has the night off.The arrival of summer brought with it humidity, bad weather and even tornados for areas in southern Minnesota.As tornado warnings sounded so did concerns about the path of storm, News 12s Erin Reed explains why tornado sirens may not have been necessary.(NATS Sheriffs Dept Video)As tornado warnings popped up in several counties around southern Minnesota yesterday evening tornado sirens were activated.North Mankato Emergency Management Director Marion Haayer says, "It's our responsibility as a city to let the residents know if there's severe weather of any kind."Counties in the warning included Faribault, Blue Earth, Waseca and Freeborn.But only parts of each county were actually under the gun.Mitch Keegan says, "The warning was for the north east parts of Faribault County, parts of south east Blue Earth County, parts of southwest Waseca County and parts of north west Freeborn county., kind of near the Minnesota Lake area."In 2007 the National Weather Service implemented an alert system - called polygon warnings -set up to only alert the part of the county in the path of the storm.Mitch says, "It's supposed to be less alarming with these new surface based warnings, or polygon warnings but because some storm sirens are still going off because portions of the county are under warning, you're still getting some of that false alarm."News 12's Erin Reed says, "Older alert systems caused sirens to activate here in North Mankato, which is in Nicollet County and was not a part of the warning area.Something emergency management officials say is due to how close the towns are."Marion says, "Because Mankato and North Mankato are in such close proximity to each other that the sirens are also activated in North Mankato."But KEYC meteorologist Mitch Keegan says countywide warnings could lead to false alarms.Mitch says, "If that warning was for all of those counties we would have been talking about 2600 square miles of land. Whereas just having that warning for just those specific parts of the county where the storm was for, was only 277 square miles."Although the new warning system began in 2007 Mankato and North Mankato are still set-up to make alerts county wide.Marion says, "Possibly in the future the technology might allow us to separate the siren system so that if the southern part of a county is activated the northern part would not be notified, but at this time it's county wide."So depending on what county you're in, if you hear sirens its best to tune into TV or a radio to stay informed.In North Mankato Erin Reed, News 12.