textproduct: Grand Rapids

KEY MESSAGES

- Isolated showers this evening

- A few Showers Sunday afternoon

- Unsettled weather Tuesday and beyond with rain chances daily

DISCUSSION

Issued at 156 PM EDT Sat Sep 12 2026

- Isolated showers this evening

Surface temperatures have warmed a bit and dew points have increased a couple of notches as compared to the last couple of days. This is evident in the satellite imagery with quite a bit more cumulus development over the area today away from Lake Michigan. This is due to the increased flow ahead of the cold front that is over Central Wisconsin as of just before 2 pm.

Even though the sfc is seeing a bit of moisture ahead of the front, the column as a whole is relatively dry with a lack of a good feed of deep moisture present. In addition, the upper wave supporting the front remains over Southern Ontario, with little to no deep forcing down this way. This continues the mainly dry forecast with about a 10% chance of something popping up with the front late this afternoon and evening.

- A few Showers Sunday afternoon

The first half of Sunday will be dry with cooler air coming in behind the departing cold front. We will see another chance of rain develop Sunday afternoon, over mainly the southern portion of the forecast area.

The feature responsible for this chance of rain is another upper level short wave that digs a bit further SE than the one responsible for today's front. The forcing with this wave, along with the convergence and limited moisture pooling along the sfc front will provide for a band or two of showers Sunday afternoon with diurnal heating. Limited low level moisture and temps will keep thunder from being possible as sfc based and elevated LI's are well above zero C, and MU CAPE is zero.

This should move south of the area by 00z Monday, and allow sfc ridging to build overhead for Sunday night and most of Monday. The air mass will be noticeable cooler behind the Sunday front.

- Unsettled weather Tuesday and beyond with rain chances daily

SSW flow at the sfc and aloft will increase quickly late Monday night on the back side of the sfc ridge, and ahead of the next system. This system is currently an upper low just off of the Pacific Northwest. This system will rotate eastward and eventually northeast by Tuesday.

The warm front will move through Monday evening, with little to no precipitation for our area through the daylight hours, as the low level jet and moisture axis stays well west of the area. The low level jet moves overhead on Tuesday ahead of the front, but much of the showers/storms will stay north of the area. We will see some rain chances on Tuesday, but much of the activity will stay NW.

The cold front is forecast to stall out, just as it passes south of the forecast area Tuesday night. It becomes parallel to the upper flow with the main energy driving NE into Canada.

The rest of the forecast period through next Saturday will be focused on the stalled out front near the area. We will see short wave activity ride along the upper flow from the WSW, and initiate rounds of showers and storms. The exact placement of the front at any time is quite uncertain, and thus the rain chances will be also. The front will be close enough through the entire period at this time to justify chc pops right on through next Saturday.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 156 PM EDT Sat Sep 12 2026

Scattered afternoon cumulus clouds with bases around 4,000 feet will become few this evening. VFR will prevail except for potential for IFR patchy fog or low ceilings at LAN and JXN between 08 and 13 Z, which the consensus of short-term models is currently leaning towards.

MARINE

Issued at 156 PM EDT Sat Sep 12 2026

We are coming to the end of the current Small Craft Advisory / Beach Hazards event, and will start to address the next event for Sunday.

Waves near and north of Little Sable Pt are likely still just high enough to need to keep the headlines for now. The observations near KMKG shows that the headlines for that area can be cancelled a bit early. The waves for the far north will come down through this evening, and can be cancelled or expired.

We will see the winds and waves pick up once again later tonight, and more so Sunday afternoon. Waves might come close to criteria overnight, but will be solid on Sunday with colder air coming in behind tonight's front.

GRR WATCHES/WARNINGS/ADVISORIES

MI...Beach Hazards Statement until 8 PM EDT this evening for MIZ037- 043. Beach Hazards Statement from Sunday morning through Sunday evening for MIZ050-056-064-071. MARINE...Small Craft Advisory from 11 AM to 11 PM EDT Sunday for LMZ844>847. Small Craft Advisory until 8 PM EDT this evening for LMZ848-849.