textproduct: Grand Rapids

KEY MESSAGES

- Showers lingering into the evening along and south of I-96

- Lake-effect rain and snow showers along the immediate lakeshore mainly north of Pentwater

- Quiet and mild weather early next week

DISCUSSION

Issued at 200 PM EST Thu Nov 12 2026

Batch of persistently moderate rain showers has slowly nudged westward to a Holland to Kalamazoo line. Radar estimates in excess of an inch are common (values are probably slightly inflated due to melting layer effects). The forcing is associated with ascent at the terminus of the broad deformation axis associated with the departing cyclone over the Lower Great Lakes. The cyclonic branch of the deformation conveyor continues to support a steady moderate rain. This forcing is expected to wane in the next couple of hours as the flow finds a new balance state, while a second pulse of forcing over east-central Lower Michigan takes over for a brief time before also weakening.

The incoming cold airmass has also activated Lake Michigan. A steady-state northerly flow will maintain the deep lake-effect bands well offshore - with exception near Big Sable point, where the primary band will flirt with the shoreline. Current CAM guidance wavers - but keeps it offshore most of the night into Friday. Otherwise, lake-effect from Lake Huron will try to squeeze a couple bands toward the southwest that may graze eastern Ingham and Jackson Counties, but prospects for any meaningful precipitation in the form of snow are very low.

As the flow gains a slight west component late Friday and Friday night, the main band structure over Lake Michigan will wander to this side of the lake - likely bringing a rain/snow mix along portions of the immediate lakeshore. If high enough intensity is maintained, then a period of all snow may occur - bringing minor accumulations to parts of Mason and Oceana Counties. Additional residual light snow shower activity from the Grand Traverse area may make inroads along and north of US-10.

The airmass begins to moderate Saturday night and Sunday, deactivating the big lake. The high amplitude upper-level ridge poised over the western CONUS will become the dominant weather governor for a good portion of next week - with mild and quiet conditions expected, once again.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 1217 PM EST Thu Nov 12 2026

Concentrated area of showers will affect KGRR, KAZO, and KBTL this afternoon - while scattered showers linger around the other terminals. Near surface moisture is higher across center Lower Michigan, thanks to contributions from Lake Huron. Ceilings continue to respond hovering at low MVFR or IFR - with the exception being MKG, where subsidence has eroded the cloud field some. Rather persistent pattern this afternoon will start to dry out after sunset - as the main low exits east. Lake-effect off of Lake Huron will maintain lower clouds for LAN and JXN. Expecting the showers (both rain and snow) will remain east. Otherwise, steady northerly flow will hold into Friday - with plenty of VFR clouds.

GRR WATCHES/WARNINGS/ADVISORIES

MI...None. MARINE...Small Craft Advisory until 7 PM EST Friday for LMZ844>849.