The Northern Midwest and Great Lakes regions brace for severe weather and possible tornadoes. The Southwest continues to face serious flood threats as more storms and rain move into the areas already drenched by Rosa. Meanwhile, fall and summer continue to battle over control of the country.

Welcome to the Wednesday edition of your Morning Briefing, where we’ll give you a mid-week rundown on everything you need to know. As always, let’s dive right in.

Enhanced Risk for Severe Weather in Upper Midwest and Great Lakes:

  1. Clashing frontal boundaries will produce severe thunderstorms in the Upper Midwest and Upper Great Lakes regions into this evening
  2. Risk in northern WI and MI is enhanced, meaning the chances of this area getting damaging severe storms are greater.
  3. There is a 10% risk for tornado development in northern WI, which is categorized as very high. People in these areas must heed local warnings, be alert, and be ready to take shelter underground if needed.

States in the regions near WI and MI are in for some trouble later today as there is enhanced risk for severe thunderstorms, meaning that there is a high chance for widespread, damaging storms with hail of 1-2″ possible. These storms will occur this afternoon and into tonight as a warm front coming up into the region from the south clashes with air moving in from a deepening trough to the northwest. Although almost the entirety of the Upper Midwest and Great Lakes regions are at a risk for severe storms, northern WI and MI have the added threat of an enhanced tornado risk. This means potential damaging and dangerous conditions for these areas.

Flooding Will Continue Today in the Southwest:

  1. Hurricane Rosa flooded much of the southwestern US yesterday and continues to rain down on many areas. Flash flood and flood threats remain in effect for many areas in NV and AZ until tonight.
  2. More rain was observed yesterday in many parts of the region than haven’t seen rain in a year. Although beneficial, these areas are very prone to flash flooding as a result.
  3. Muddy and murky waters from the sand and dirt can present dangerous driving conditions as streets continue to flood from heavy rain today.
  4. Storm formation can produce locally heavier rain in some areas.

Heavy rains from the remnants of Hurricane Rosa drenched the southwest US earlier this week. Many parts of the region saw more rain in two days than they had seen all year. Yesterday, Phoenix reported over 2″ of rain, making it one of the city’s wettest days in recorded history. Although most of the post-tropical storm has dissipated and moved on, some showers and possible storms still linger. Flash flood advisories remain in effect for most of the Southwest, especially areas in Nevada and Arizona that saw the most flooding yesterday. Flooding mixed with loose sand and dirt in these areas also presents the danger of mudslides. Residents are advised not to drive through flooded or very muddy areas, as the depth of muddy water can be deceiving. Storm formation is possible within these last few pockets of tropical energy, which would cause locally higher flooding and increase risk.

Fall and Summer Battle For Control of the US:

  1. Low pressure moving in on the west coast today will provide relief from hot summer temperatures in the Northwest and Upper Great Plains.
  2. These cooler temperatures will try to make their way across the country, but will come into contact with the high pressure system in the Deep South that dominates and keeps hot air in the region.
  3. By the weekend, cooler temperatures will dominate most of the west and hotter temperatures will remain the east.

A hot start to the week may not have relief in some parts of the country. A strong low pressure trough will move into the western coast aloft today. As it makes its way across the US, it will allow flow from the north to bring cooler Canadian air to parts of the country yet again for the end of the week. However, this low pressure will continue to battle dominating high pressure in the Deep South, keeping hot, oppressive summer air in that area. A surface high, combined with flow from the trough aloft, will bring colder temperatures into the Upper Great Plains today and Thursday. This pair will make its way across the country, cooling down significant portions of the northern half of the US by Friday. Friday afternoon, the stubborn high pressure in the south will stand its ground, stalling, and as a result deepening the trough over the west. This weekend we will see hot summer in the east,and cool fall in the west as these seasons continue to fight it out.

Make sure to subscribe to The Morning Briefing on the right-hand side of this article so we can send the Wednesday and Friday editions straight to your inbox.

Also remember to lookout for The Sunday Storm this upcoming Sunday evening as well as Five Things to Watch This Week on Monday.


Kathleen is a Meteorologist at WeatherOptics, where she works writing content for the website, providing accurate and detailed forecasts to clients, and consulting on various meteorological projects. Kathleen earned her B.S. in Atmospheric and Oceanic Sciences in 2018 from Stony Brook University. Kathleen has also done research into our changing climate by investigating theRole of Atmospheric Rivers on Arctic Amplification in 2017.

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