textproduct: Grand Rapids

KEY MESSAGES

- Scattered Showers and Storms This Afternoon, Flooding Continues

- Chance of Severe Storms Friday Night

- Cooling and Breezy Sunday

- Dry Early Next Week

DISCUSSION

Issued at 251 PM EDT Thu Apr 16 2026

- Scattered Showers and Storms This Afternoon, Flooding Continues

Scattered showers and storms have begun to develop across Lake Michigan and southern Michigan. Storms are possible through roughly 00z when the stationary front assisting potential development is shifted east by approaching ridging. Marginal instability is developing with SBCAPE on the order of 500-1000 J/kg will develop. Strong kinematics will put in excess of 40 knots of deep layer shear across our southeast CWA (towards Lansing and Jackson). As such, cannot completely rule out strong to marginally severe winds and hail across this region through early evening. Partial clearing overnight then will support fog development overnight with some guidance suggesting it may be potentially dense.

Areal flooding has ended with the widespread heavy rain shifting east. We could see isolated pockets of 0.25-0.5" of rain under any thunderstorms but this activity will be scattered. Widespread river flooding will continue to be a concern, see the hydro section for more details.

- Chance of Severe Storms Friday Night

Conditions will be dry during the daylight hours on Friday as surface and upper-level ridging drive a dry profile and large scale subsidence.

Attention then turns to late Friday evening into Friday night as storms from the west congeal into a line as they cross into lower Michigan. Given the trend in the latest CAMs for earlier storms, the marginal risk has expanded east with a slight risk for our southern lakeshore counties. Advection of moisture ahead of the line will result in MUCAPE on the order of 1000-2000 J/kg with 40-50 knots of deep layer shear. This brings concerns for severe weather across west Michigan, highest close to the lakeshore. Primary concern is for damaging winds in any bowing segments, with a very low chance of a tornado given ample low-level instability and shear. Storms will clear the area by early Saturday morning.

- Cooling and Breezy Sunday

Large scale troughing moves overhead Sunday leading to a notable pattern shift across the area. Highs fall into the 40s Sunday with lows Sunday Night potentially into the 20s. Winds gusting to around 30 knots Sunday afternoon may bring wind chills Sunday down into the 20s as well, which will feel downright bitter compared to recent weeks.

- Dry Early Next Week

We move into a relatively drier pattern into early next week as we are forecast to shift into predominantly northwest flow. Ridging should keep things dry for the most part, however weak signals have developed for showers Tuesday with a cold frontal passage. Highs warm into the 60s by mid next week.

AVIATION /00Z TAFS THROUGH 00Z SATURDAY/

Issued at 745 PM EDT Thu Apr 16 2026

Showers may try to move into LAN, otherwise dry conditions are expected. Ceilings will gradually lower to IFR values tonight as low level moisture advects in from the west. Ceilings have already fallen to 400 feet at BIV and areas south along the lakeshore with visibilities below a mile. Expect these conditions to expand east with IFR and LIFR visibilities until 14-15Z as the fog lifts. Winds will be light and variable before becoming southeasterly Friday morning.

MARINE

Issued at 251 PM EDT Thu Apr 16 2026

Benign marine conditions are expected through much of the day Friday before winds and waves increase later Friday into the weekend. A small craft advisory is likely to be needed. Marine Dense Fog is likely overnight into Friday morning and the current advisory remains unchanged. A line of thunderstorms then crosses the lake Friday night with the potential for winds in excess of 34 knots.

HYDROLOGY

Issued at 251 PM EDT Thu Apr 16 2026

Bottom Line Up Front: Significant flooding continues on the Muskegon River with minor to moderate flooding expected in the Grand River Basin through the coming days.

Overnight last night, 1 to 3 inches of rain fell across the lower Muskegon River basin, with isolated pockets in the Grand River basin as well. This will make its way into the river system resulting in flooding. Major flooding is expected along the Muskegon River at all forecast points, with minor to moderate flooding forecast for the Grand River and its tributaries.

The Kalamazoo River basin seeing less rain of late, no river flooding is expected. Our Saginaw River basin points at the Chippewa River at Mt. Pleasant, and the Pine River at Alma are also forecast to reach minor flood stage.

Little additional rainfall, outside of thunderstorms, is expected through the daytime hours Friday. Thunderstorms then bring widespread totals of 0.25-0.75" Friday Night into Saturday, highest near I-94. Given the saturated antecedent conditions, urban and small stream flooding is possible with thunderstorms, particularly Friday Night.

GRR WATCHES/WARNINGS/ADVISORIES

MI...None. MARINE...Dense Fog Advisory until 8 AM EDT Friday for LMZ844>849.