textproduct: Grand Rapids

KEY MESSAGES

- Chance for Severe Storms this afternoon and evening

- Slight Risk for Severe Weather Tomorrow, Minor flooding possible

- Quieter Late Week with rain and storms possible Sunday

DISCUSSION

Issued at 252 PM EDT Tue Jun 16 2026

- Chance for Severe Storms this afternoon and evening

Storms have begun throughout the southern Peninsula today. An upper level trough is bringing a short wave with two LLJ's associated with it. The first LLJ is associated out ahead of the trough and is driving the current storms moving through Central and Eastern Lower MI. Two more lines will be moving through MI as the day progresses. Those have the potential to be stronger as a perpendicular 40kt LLJ will be driving those storms. Low topped supercell thunderstorms will be the main mode of convection. While there is not a lot of DCAPE over the region, there is around 1000 J/kg upstream. With MUCAPE around 1K J/KG and increasing bulk shear there will be an increased risk for severe storms. The strongest storms should be associated with the front as it moves through between 6 PM and 9 PM. The main threat will be from damaging winds and large hail. However, With PV anomalies and the previously mentioned LLJ providing sufficient shear, there is a chance for tornadoes, especially through far southwest Michigan. - Slight Risk for Severe Weather Tomorrow, Minor flooding possible

Another round of storms remains likely tomorrow. A large upper level low will move through WI, IL and into IN. The best forcing, along with upwards of an 80kt LLJ, will be through those regions with MI being in the warm sector. The boundary will remain through far southern Michigan. So while storms are expected and damaging winds will be possible, the biggest threat will be from heavy rainfall. Anomalous 1.5 inch to 2 inch PWATS with strong moisture transport vectors are indicative of the plethora of moisture associated with the system. As the low moves overhead there should be a long residence time, with 1 to 2 inch per hour rates. Due to this there is expected a wide swath of 1 to 2 inches along and south of the I-96 corridor with locally heavy amounts upwards of 3 or more possible. The best threat for showers and storms will be later in the day. Given those conditions, minor flooding will be possible, especially along and south of the I 94 corridor.

- Quieter Late Week with rain and storms possible Sunday

Cooler, drier flow will move through in the wake of the system with broad high pressure. The next chance for rain will be from a large upper level low that drops from the north and coincides with a mid level and sfc low propagating eastward. There is some questions on timing and position but late in the weekend to early next week should be a rainy and stormy period.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 141 PM EDT Tue Jun 16 2026

Showers and storms continue to develop over Wisconsin and Lower MI. Some of those storms could be strong to severe this afternoon and evening. An upper trough is responsible for the storm development. Generally VFR conditions are expected through the period. However, during storms, MVFR and potentially IFR visibilities are possible.

MARINE

Issued at 319 PM EDT Tue Jun 16 2026

Small craft advisory and beach hazards statement remains in place through the rest of the evening. After the frontal system passes the winds and waves will subside. Showers and storms will move through tomorrow, though winds and waves will be offshore. Another round of strong winds and waves are expected tomorrow night into Thursday.

GRR WATCHES/WARNINGS/ADVISORIES

MI...Beach Hazards Statement through late tonight for MIZ037-043-050- 056-064-071. MARINE...Small Craft Advisory until 4 AM EDT Wednesday for LMZ844>849.