textproduct: Grand Rapids

KEY MESSAGES

- Storms lingering into this evening

- Severe weather potential increasing for the Monday night time frame

- Cooler and mostly dry from Tuesday through Friday

DISCUSSION

Issued at 245 PM EDT Fri Apr 24 2026

- Storms lingering into this evening

The radar across Southern Lower Michigan has been lighting up a bit over the past 1-2 hours as expected ahead of the incoming cold front. The cold front appears to be caught by radar and verified by sfc obs to be located just east of Holland to near Big Rapids and of 210 pm this afternoon.

Ahead of this front, MU CAPEs have increases to over 1,000 J/kg with some sunshine and advection of moisture in the lower levels. The storms that have developed have been behaving as expected with weak deep layer shear values as we have been advertising for days. Small hail and winds gusts of 40 mph are the most likely threats from these storms. The threat is likely to be exiting the area to the east toward 00z/8 pm EDT this evening as the front exits the area at that time.

We will see cooler air behind this front as 850 mb temps drop from around 13C today to around 7-9C Saturday afternoon, and then slightly warmer on Sunday as the thermal trough moves by and we start to see return flow. Upper ridging building in behind the front will bring dry conditions with a good deal of sunshine during our longer April days.

- Severe weather potential increasing for the Monday night time frame

As we see this current system exit the area in the next few hours, our next focus becomes the system that is forecast to approach the area on Monday, and move through around Monday night. This system is looking more and more ominous as more details become visible as we get closer to that time frame. That said, there are some slight timing differences and strength of parameters. Definitely something to watch.

The overall pattern remains the same with a cutoff upper low over Saskatchewan driving the pattern over much of the country. This low will help to steer a wave currently offshore of CA and lift it to the NE toward later Monday. There is some broad agreement that showers and storms ahead of the front will arrive as early as Monday evening, and as late as the pre-dawn areas Tuesday morning. Most of the Model ensemble means are showing some healthy MU CAPE advecting in ahead of the sfc front, and the supporting upper wave. Some of this could even be sfc based even coming in overnight. Deep layer shear values are likely to be fairly favorable given the stronger upper level winds expected to be in place, as will be the low level shear as 850 mb winds are expected to be upwards of 40 knots. To help this cause, the upper wave is expected to be nearby to help force convection.

Again, being 4 days out, still a lot could change. But this is something that could cause some trouble.

- Cooler and mostly dry from Tuesday through Friday

As we see the system Monday night move out on Tuesday, we are looking at an even cooler air mass move in, with mostly dry conditions. This will take place as we see somewhat of a return to the pattern of the upper flow from the NW like much of this past winter saw.

There do look to be some ripples in the flow that might keep the precipitation chances from being zero. However, there will be quite dry air in place, so it will be tough for rain to make it to the ground. 850 mb temperatures will drop below 0C by Wednesday evening and remain there through Friday. These types of 850 mb temperatures will support highs in the 50s.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 702 PM EDT Fri Apr 24 2026

VFR conditions are present across West Michigan with VFR rain showers likely for the next hour or two, mainly at JXN. Low clouds begin developing late tonight with the lowesr cigs for LAN/JXN where more widespread rain occured with this afternoon's showers and storms. Most sites will reach IFR overnight with the exception of MKG where MVFR is favored. The cloud deck will lift over the course of the late morning and into the afternoon on Saturday. However, it is not clear at this time whether LAN/JXN will be able to break into VFR conditions by the end of the TAF window. Winds will go from westerly at present to northeasterly by Saturday afternoon, with gusts to around 20 knots possible Saturday afternoon and LAN/JXN.

MARINE

Issued at 245 PM EDT Fri Apr 24 2026

We will be flirting with SCA conditions for a brief period this evening across the northern marine zones, and across much of the marine area on Saturday. We have determined in collaborating with neighboring offices to hold of on headlines for now. This evening's winds will be barely hitting criteria, and for only 2-4 hours. Saturday's pattern is the ridge building in, and a mesoscale stronger gradient right along the shore. This may still possibly need a headline, and future shifts can monitor that need to hoist.

The next period of concern will be starting Sunday night and lasting through much of Tuesday. We will see the gradient strengthen out ahead of the late Monday system, and continue through Tuesday when we will see the cooler air arrive behind the front.

GRR WATCHES/WARNINGS/ADVISORIES

MI...None. MARINE...None.