Severe Weather Event on Sunday, July 12
The complex of severe thunderstorms that developed across eastern North Dakota and western Minnesota on Sunday produced damaging winds and hail as it moved east across Minnesota and then dove southeastward toward Southern Wisconsin and Northern Illinois. According the Preliminary Local Storm Reports available from NWS Storm Prediction Center (SPC), the worst of the activity was clustered in central Minnesota as well as in Southern Wisconsin. A few tornadoes were reported in far West Central Minnesota, but most of the reports were severe winds and large hail. Another storm causes severe wind in western South Dakota were several locations reported wind gust between 60 and 70 mph. The graphic below highlights the severe weather reports provided to the NWS on Sunday. The colored regions show the NWS SPC Outlook that was issued early Sunday Afternoon. The area shaded in yellow is the slight risk, the Orange is the Enhanced and the Red is the Moderate Risk.
Severe Weather Outlook for Today, July 13
While the storms remained Strong to at times Severe as they moved into northern Illinois overnight, the number of damage reports so far today, have been minimal. However as the atmosphere begins to heat up and recharge, thunderstorms will develop this afternoon. NWS SPC has highlighted an area of Moderate Risk (shown in red below) for Severe Thunderstorms across much of Illinois, parts of far Southwest Indiana and far Western Kentucky. A larger area of Enhanced Risk (shown in orange) extends across Indiana, southwestern Ohio, Kentucky and into Tennessee.
A breakdown of the NWS SPC thunderstorm risk categories is below. The Moderate Risk indicates widespread, long lived and intense severe storms are likely; Enhanced identifies areas where some storms may be intense but not as widespread as a Moderate area.
Initial areas for thunderstorm development during the mid afternoon hours will be along a boundary created by the storms from overnight and this morning in Eastern Iowa and Illinois. With very warm and humid air at the surface and additional upper level dynamics in place, the atmosphere is unstable and very strong to severe storms are likely this afternoon and evening. The tornado risk is slightly higher today than it was yesterday with NWS SPC showing a 10% probability for west central Illinois (graphic below).
The area of concern for tornadoes is also the area of heightened concern for large hail (see below).
A broader area of the country has the potential to experience damaging winds. The graphic below outlines the regions that could see wind gusts in excess of 58 MPH. The areas in the Red and Pink show the regions with the higher likelihood of seeing severe winds with the area outlined in black and hatched shows the risk of significant wind speeds which are 74.8 mph (65 knots) and stronger.
Severe Weather Outlook for Tuesday
While not as widespread, the threat for severe weather sinks further south on Tuesday. Below is the NWS SPC outlook for severe weather on Tuesday. Areas including Kentucky, Tennessee, Georgia, South Carolina and North Carolina have an enhanced risk for severe weather. Severe winds, large hail and even tornadoes are of concern for Tuesday with the area of highest risk for tornadoes in eastern Kentucky and Tennessee.
For those in the Midwest/Ohio River Valley, we encourage you to remain in tune for rapidly changing weather conditions and have a way to be notified of any watches and warnings that may be issued for your location. To prepare for the severe weather threat, if you have any loose items or equipment outdoors that could easily become airborne such as lawn chairs, umbrellas, pool toys, bring them inside. Also bring inside any items that could easily be damaged by large hail which includes vehicles. If Warnings are issued for your location, move into an interior room on the lowest floor and stay away from windows as severe winds, especially when combined with large hail and/or debris, can shatter windows.
The team at WxIntegrations will continue to provide relevant information and resources to help you better understand and prepare for the forecast weather through incorporating weather impacts into your planning and response.