Several Days of Warm, Humid Weather With Daily Flooding and Severe Weather Chances

Summary:

As mentioned in yesterday's social media posts, this week will be very warm and humid and will feature daily chances for showers and thunderstorms. These chances for showers and storms will come with attendant risks for excessive rainfall that may lead to some minor flooding and some low "all-hazards" severe weather potential as well. We'll break down what you can expect for each day here in this forecast.

Day 1 - Today (Monday 07/29/2024):

Focus for today remains on Southwest Lower Michigan late this afternoon into the evening and overnight hours. Showers and thunderstorms moving into lower Michigan and could take advantage of the modestly unstable environment and become somewhat strong to locally severe posing a low-end all-hazards severe weather risk across areas generally along and South of the I-94 corridor and West of the I-69 corridor. The threat for severe weather is rather low and uncertainty certainly exists with this threat but some small to large hail, a localized damaging wind gust, and a brief, weak tornado cannot be ruled out so make sure that you stay weather aware and have ways to receive weather alerts.

The more likely threat overnight tonight is the risk for heavy rainfall, and possibly excessive amounts of rainfall, to cause some localized minor flooding. Once again this risk is focused on the aforementioned region in far Southwest Lower Michigan. These areas have already experienced above-average rainfall amounts and rather uncommon amounts of flooding as a result. The ground in this area remains at least somewhat saturated and waterways, while below flood stage, still have above-average flow/water levels so flooding and flash flooding will continue to be a concern.

Day 2 - Tomorrow (Tuesday 07/30/2024):

Showers and thunderstorms will be possible Tuesday morning as well and could also be possible through the remainder of the day but details surrounding Tuesday remain heavily reliant on the performance of showers and storms today and overnight tonight and hence the confidence and forecast details for Tuesday remain very low.

As of now, it looks as if the severe weather threat will be concentrated on the same areas as today's threat and will continue to be an all-hazards threat for wind, a tornado or two, and hail even though the SPC is not highlighting any hail potential... some models (and local WFO forecast guidance) suggests that some small to large hail may be possible both today (Monday) and tomorrow (Tuesday).

With regards to the Excessive Rainfall and flooding threat; the WPC rainfall outlook shows that the threat will include the same areas over Southwest Lower Michigan as today's risk does but also expands the risk to the East to encompass Branch, Eaton, and Calhoun counties in our coverage area. These areas have also experienced above-average rainfall and some flooding already this year so we'll be keeping a close eye on this threat for these areas as well on Tuesday.

Stay tuned for forecast updates for Tuesday later this evening and tomorrow morning.

Day 3 - Wednesday 07/31/2024:

On Wednesday we will see a much more widespread chance (still low chance) for severe weather and flooding across much of our coverage area. The overall weather pattern will begin to bring shortwave troughs through the region on Wednesday. These shortwave troughs can serve to act as forcing mechanisms to spark shower and thunderstorm development. When we look at severe weather chances we look at 4 major elements: wind shear, moisture, instability, and lift. We will certainly have the instability and moisture in place this week given the hot, humid airmass in place and Wednesday will be no exception... however, chances remain low because we may be lacking the other 2 ingredients to some degree. These shortwaves do not currently look to provide anything substantial in terms of wind shear and will be relatively weak and slow-moving.

However, some guidance does suggest that this could change so we'll need to watch this potential as we get closer to Wednesday for the potential to see the severe weather threat increase.

In terms of heavy rainfall, Wednesday is our biggest concern, especially for far Southwest Michigan where the WPC has outlined a small Slight Risk region for Excessive Rainfall. Precipitable water values are in excess of 2 inches for much of the day Wednesday so flooding and heavy rainfall will definetly be a concern.

Day 4 - Thursday (08/01/2024):

A statewide risk for heavy rainfall and flooding will exist for Thursday as Precipitable Water values will continue to be in excess of 2 inches and several rounds of showers and thunderstorms will move across the state.

Additional details surrounding Thursday will be discussed later this week as the forecast and models come into better agreement.

Day 5 - Friday (08/02/2024): A more appreciable severe weather threat could exist Friday but details surrounding that potential are highly uncertain and very much dependent on how the rest of the week performs.

We'll continue to monitor the potential for Friday as well and will provide updates as we head into late week.