This Afternoon/Evening/Overnight Tonight:
Today's severe weather risk remains unchanged since this morning's discussion (see below). It remains possible that a complex of showers and thunderstorms will move through areas generally South of the I-96 corridor later this evening and into the overnight hours probably closer to midnight tonight. While severe weather chances remain possible this evening, the threat is largely uncertain so we'll need to continue to closely monitor this as we head into the evening hours.
Heavy rainfall is becoming increasingly concerning for tonight however, and there has been a change to the WPC Excessive Rainfall Outlook which has upgraded portions generally South of M-46 and West of US-131 to a level 2/4 Slight Risk.
Tomorrow Evening/Overnight Into Tuesday:
Tomorrow's severe risk has been upgraded to an Enhanced Risk (Level 3/5) for some of the Southwestern parts of our coverage area.
Tomorrow has been the primary focus of our forecasts for the last several days and this afternoon in no different. A more widespread, and perhaps more significant, severe weather threat is on the table for tomorrow evening and into the overnight hours. While the greatest threat will likely largely stay to our Southwest we are certainly in a risk area that could see some severe weather given the very favorable environment in place.
This is primarily driven by an upgrade to the Damaging Wind risk from 15-29% to 30-44%.
A SIGNIFICANT WIND risk (indicative of a 10% or greater risk for at least one damaging wind gust over 75 MPH within 25 miles of a point has also been introduced within the black circled and hatched region on the "Damaging Wind Gust" map shown below.
Overall, uncertainty remains rather high at this time but an environment that is supportive of all-hazards severe weather, possibly significant severe weather, is in place across much of the area tomorrow and folks need to remain #WeatherAware! Stay tuned for updates!
Previous Discussion:
Issued at 9:20 AM Local Time Sunday 07/14/2024 Summary:
West Michigan Weather forecasters have been tracking the threat for severe weather and heavy rainfall this weekend and early this week for several days now. So far we've generally gotten by unscathed, an isolated stronger storm aside. This may change as we head into the evening and especially tomorrow afternoon and evening. We need to stress, however, that confidence remains relatively low so our primary message at this time is to stay #WeatherAware and watch for later forecast guidance.
Today (07/14/2024):
Shower and thunderstorm activity just offshore of Wisconsin over Lake Michigan is tracking towards West Michigan as of writing this forecast. This activity is not expected to be severe and substantial questions remain as to how well it will hold up over the lake and to what amount of geographic coverage this activity will cover over West Michigan as we head towards the late morning/early afternoon hours today.
Our primary focus for today will be any potential re-development we may see later this afternoon and evening. Any new re-development that occurs will pose a limited all-hazards severe threat as well as a heavy rainfall/flooding threat. Confidence in this re-development is rather limited and will be hampered by the aforementioned shower and thunderstorm activity currently crossing Lake Michigan as it taps into the environment, prevents substantial daytime heating/de-stabilization, etc. If redevelopment does occur the best chances for strong to severe storms and flooding will generally be along and South of the I-96 corridor, especially along the I-94 corridor and West of US-131 in the Slight Risk boundary where there is a more supportive environment for damaging wind gust delineated by the new SPC 15-29% damaging wind risk.
Monday (07/15/2024):
Our biggest concern for the last several days has been the potential for a more robust/widespread severe threat to be in place on Monday evening and our attention will quickly turn to this after we get through today's potential severe weather.
Currently, there is quite a bit of uncertainty surrounding the forecast for Monday, primarily because any shower or thunderstorm activity we see this evening/overnight will have a large impact on the potential for showers and thunderstorms tomorrow.
SPC currently has an all-hazards risk in place highlighting a broad Slight Risk (level 2/5) across much of the area. This risk is driven by a 15-29% chance of damaging wind gusts. Higher outlook probabilities are not at all out of the question with this risk... there just isn't enough confidence at this time to warrant such probabilities.
As aforementioned, the environment will be supportive of all severe weather hazards. Modestly curved low-level wind profiles and SRH (Storm Relative Helicity - storm spin) will be supportive of at least an isolated tornado threat and substantial to even extreme instability will foster an environment favorable for damaging winds backed by a 30-55kt low-level jet. Hail will also be possible in the storms with the strongest precipitation cores.
Flooding will also be a larger concern tomorrow. Given the remnants of Hurricane Beryl earlier this week and the recent unrelated shower and thunderstorm activity we have seen across our Southern zones especially, we will need to prepare for an already saturated ground and waterway system to be overwhelmed to at least some degree which may lead to some isolated to scattered flooding or flash flooding. WPC has currently outlined a Slight Risk (level 2/4) for Excessive Rainfall tomorrow and we'll continue to monitor this threat. Persons in low-lying areas and along waterways should make plans for potential flooding to be on the safe side.
Comments