textproduct: Grand Rapids

KEY MESSAGES

- Showers and Storms Today

- Colder with some Lake Effect Snow Sun-Tues

- Some Precipitation Thu-Sat

DISCUSSION

Issued at 351 AM EDT Sat Apr 4 2026

- Showers and Storms Today

Showers and thunderstorms are ongoing at this time (330am) and will continue through the morning. In fact we expect an increase in coverage early this morning as a strong low level jet moves in. Instability is not strong and not forecast to become strong this morning, holding on the order of 500 j/kg or so. This should not be enough instability to result in severe weather. A cold front will move through and clear the better rain chances to the east later this afternoon. Not out of the realm of possibilities to see a stronger storm towards Jackson in the mid to late morning ahead of cold front, but again severe weather is unlikely. See the hydro section below for details.

- Colder with some Lake Effect Snow Sun-Tues

The cold front will usher in a much colder airmass over time. Highs Sunday through Tuesday will be in the 40s. We will be cold enough for some lake effect snow from Sunday night through Monday night. Some locations downwind of the big lake will see the ground turn white again with accumulations ranging from trace amounts to around 1 inch.

- Some Precipitation Thu-Sat

A cold front will move into the region Wednesday night and stall out on Thursday. Rain showers are expected during this time frame. Beyond Thursday there is some disparity in the models but it appears wet weather may continue, especially when looking at the GFS. Temperatures warm back into the 60s for highs during this time frame. Very much a spring like pattern as temperatures whip back and forth both above and below normal.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 743 AM EDT Sat Apr 4 2026

Widespread showers are now over the area just before 12z, with isolated lightning also being observed. Just about all of the area is IFR with regards to ceilings. We expect that the thunder potential will have ended at KMKG by 12z, and will quickly diminish by 15z at all of the terminals. This will leave showers through much of the rest of the day. IFR to LIFR conditions will rule mainly due to the ceilings.

Rain showers should start to diminish from west to east this afternoon and through the evening hours. Conditions will improve a bit as somewhat drier air moves in and lifts ceilings to MVFR. Then late tonight, a few rain and snow showers will rotate through the area, bringing additional MVFR conditions.

MARINE

Issued at 351 AM EDT Sat Apr 4 2026

A cold front will sweep through the area today and west winds will increase behind it. West winds to 30 knots looks very likely, but gales to 35 knots is plausible as well. We will be monitoring closely from late this afternoon into tonight to see if gale force winds become common. Waves of 6 to 9 feet look likely on Sunday in strong cold air advection.

HYDROLOGY

Issued at 351 AM EDT Sat Apr 4 2026

2 to 4 inches of rain has fallen over the past 5 days in Southwest Lower Michigan. The ground is saturated and water is routing through the river systems. Another round of showers and thunderstorms is underway as of 300am early this Saturday morning. A classic setup for heavy rain presents itself this morning with a strong low level jet at 850mb of 45-55 knots surging PWAT values of 1.5 inches into the region. Periods of showers and thunderstorms are expected from 300am through roughly 300pm. Another 0.50 to 1.00 inch of new rainfall is expected today.

We currently have River Flood Warnings (that were issued overnight) for Maple Rapids on the Maple River as well as Vicksburg on the Portage River in effect. River Flood Watches remain at Newaygo and Bridgeton on the Muskegon.

The added forecast rainfall should send many area rivers higher. We are expecting a few more River Flood Warnings as we move through the next few days.

GRR WATCHES/WARNINGS/ADVISORIES

MI...None. MARINE...Small Craft Advisory until 8 PM EDT Sunday for LMZ844>849.