Parts of Minnesota, Iowa and Wisconsin are in the bulls eye for a significant severe weather outbreak today. The National Weather Service – Storm Prediction Center has a identified a moderate risk for severe weather for this area for this afternoon and into tonight.
NWS Storm Prediction Center Severe Weather outlook for Sunday July 12. While a broad area of the country can expect showers and thunderstorms a focused area in the Upper Mississippi River Valley is of heightened concern for severe weather.
Moderate Risk means widespread Severe Thunderstorms are expected.
The main threat for severe weather in the Upper Mississippi River Valley is damaging winds and very large hail; however, an isolated tornado is also possible. The graphics below indicate the potential for Damaging Winds, Large Hail and Tornadoes. The tornado threat is focused mainly in Minnesota, while the threat for Hail and Damaging Winds extends across the Eastern Northern Plains States and into the Ohio and Tennessee River Valleys. There is also a chance of damaging winds in Florida as well Arizona and New Mexico.
Graphics above highlight the threat for Large Hail, Damaging Winds and Tornadoes for Sunday July 12.
Ironically, evapotranspiration from the maturing corn is helping to fuel moisture in the lower levels of the atmosphere and making conditions even more unstable in the Upper Mississippi River Valley. Storms are expected to rapidly develop in eastern North Dakota and Western Minnesota this afternoon and then combine into a complex for this evening as they push east. As they form into a squall line, the threat for damaging winds will increase. The complex will push southeast through the night and gradually start to decay over Illinois Monday Morning.
The upper level system that is the trigger for severe weather today will cause another round of widespread severe weather on Monday across Illinois, Indiana and into Kentucky. NWS SPC has already highlighted an area of Moderate Risk in the areas of highest concern. While there will be a risk of isolated severe weather with the storms Monday Morning, the more organized activity will form in the later afternoon on Monday across Southern Wisconsin and northern Illinois and quickly intensify into a squall line as it moves southeast. Widespread damaging winds are of increased concern for locations such as Indianapolis, IN and Louisville, KY, Monday Evening.
The other piece of the weather story is the hot conditions. A large area of the Central and parts of the southern US are under a Heat Advisory through Monday as shown by the salmon colored areas. The areas in the deep pink in Kansas and Missouri are under an excessive heat warning. Most locations in the heat advisory areas can expect heat indicies in the 100 to 105 degree F range while the areas in the warnings can expect 105 to 115 degree F heat indicies.
Widespread heat indicies of over 100 degrees F for Today and Monday will make outdoor activities very uncomfortable and even hazardous for those sensitive to the heat.
The hot and humid conditions will continue, especially in the south, into Midweek as areas of 100 to 110 heat indicies are possible into Wednesday.
For those in the Upper Mississippi River Valley today and into the Ohio and Tennessee River Valleys on Monday, 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.
For those in the areas of the high heat and humidity, if possible limit your time outside especially in the afternoon and remain indoors in an air conditioned space. If you must be outside drink plenty of water to keep your body hydrated. For more tips to be heat prepared see FEMA’s Ready.Gov site
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.