Summary:
While confidence in any severe weather threats today still remains very low at this time (confidence should improve over the next several hours through the early afternoon) today is certainly the most concerning as compared to the last several days, both in terms of severe weather potential, and the risk for heat-related illnesses.
School Closing Outlook Results:
Last night we issued our first Level 6/6 School Closing threat of the 2024-2025 school year due to the likely widespread impacts from the high heat. View the outlook here.
As of 6:00 AM this morning, at least 7 school districts have closed entirely, more than a dozen additional schools have announced they are dismissing students and staff early, and we know that many other schools across West Michigan, if not the majority, plan to do the same based on reports we've seen on social media and through various contacts across the area. Overall, while we haven't seen as many full closures as we expected, the number of early dismissals that we accounted for in our risk yesterday is verifying quite well. Again, it is difficult for us to get a true accurate count of how many schools dismiss early but more than a dozen are already doing so. For those reasons, we believe this outlook verified quite well, with perhaps just a few refinements being made to the widespread nature of our 71%-90% chance delineation which may have made this outlook a tad more accurate.
Dangerous Heat Today:
High temperatures in the mid to upper 90s across the region coupled with high humidity values will result in heat index values that will likely exceed 105°F and could reach over 110°F across far Southwestern Lower Michigan this afternoon. Heat indices of this magnitude have the potential to significantly increase the risk for heat-related illnesses, especially for the vulnerable populations within our communities including the elderly, children, those with underlying illnesses or health conditions, and those who work outdoors.
Heat is the number 1 leading cause of weather-related deaths in the United States! Heed this threat and take it seriously! Be sure to drink plenty of fluids, make efforts to avoid the heat by remaining indoors with A/C when possible, check on your family, friends, and those around you, and be alert for the signs of heat-related illnesses!
Strong To Severe Thunderstorm Potential Today:
The National Weather Service Storm Prediction Center has maintained it's level 2/5 "Slight" risk for severe weather across our entire coverage area for today and the Weather Prediction Center has expanded it's level 1/4 "Marginal" risk for excessive rainfall to include the entire Lower Peninsula.
As aforementioned in today's forecast summary, confidence in any one scenario that involves severe weather is very low even at the near-term stage with the threat less than 24 hours away.
This is due to several factors. First and foremost, we have showers and thunderstorms that just moved through the majority of our central and Northern zones earlier this morning and are currently progressing Southeast toward Lansing, Saginaw, and the Metro Detroit area as we approach sunrise this morning.
This activity will have at least some impact on the potential for severe weather later this afternoon and perhaps into the evening and overnight period and where any outflow boundaries or other storm-scale (hyper-local atmospheric features) setup will be key to the development and intensification of any storms that form later today so we will need to wait and see how this line evolves.
In our experience, computer weather models struggle a bit with these types of setups and with the added caveat of having showers and storms moving through this morning there is a whole lot of uncertainty and we'll need to rely on "nowcasting" with surface observations and radar trends later today.
Damaging winds and large hail, along with heavy rainfall and some minor flooding risk, will be the primary threats today and frequent lightning is always a predominant feature of these types of systems in these environments. While not immediately likely, a tornado or two can also not be ruled out. Unfortunatley, our messaging has to continue to be: "stay tuned for additional details and forecast updates as the day goes on."
Current guidance suggests that the best time frame for severe weather will be after 7:00 PM this evening but any "pop-up" type storms that can develop this afternoon will also have the potential to become strong to severe.
Remember, a Slight Risk for severe weather means that there is the potential for isolated to scattered severe weather and perhaps an isolated significant severe report or two but considerable forecast uncertainty may remain as is the case today. These Slight risks can very easily realize the need for higher risk categories to be introduced and similarly can just as easily be downgraded as well.
Severe Storms Tomorrow?
Some risk for strong to severe storms may persist very early tomorrow morning and perhaps again late in the evening along and South of the I-96 corridor.
Again, substantial forecast uncertainty dominates this period as well. SPC currently has a level 1/5 "Marginal" risk in place as there is a low chance for damaging winds of 40-60 MPH and perhaps some small to large hail up to 1 inch (quarter size) in diameter.
Will need to wait to see how today's risk and any attendant severe storm activity perform prior to discussing any more specific details.
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