textproduct: Grand Rapids

KEY MESSAGES

- Beautiful Fall Conditions through Tuesday

- Rain Chances Return Tuesday Night and Continue through Week

DISCUSSION

Issued at 225 PM EDT Sat Sep 26 2026

- Beautiful Fall Conditions through Tuesday

High pressure remains in place with troughing to our east and west. Mostly sunny conditions are expected through Tuesday with highs in the upper 60s along the lakeshore to mid 70s further inland. Lows overnight will mainly be in the 40s with a few spots potentially dropping into the upper 30s tonight toward US-10.

- Rain Chances Return Tuesday Night and Continue through Week

Cluster analysis and long range ensembles all point to high pressure weakening over the area midweek with a trough moving through late Tuesday night into Wednesday. Instability is low therefore not expecting thunderstorms at this time. Moisture increases with precipitable water values around the 90th percentile (1.6 inches) shown in the mean of each cluster in the cluster analysis. There are some isolated members that approach 2 inches (record precipitable water levels) as mentioned in the previous discussion, however those probabilities are low.

Additional shortwaves move through the area for the remainder of next week. There are some differences in the extended with the timing of each of these shortwaves, but ensembles show agreement that most will see some rain accumulations each day. WPC highlights rainfall amounts in the 1-2 inch range Tuesday through Saturday. Some isolated higher amounts are possible (20 percent) as highlighted by individual ensemble members.

AVIATION /00Z TAFS THROUGH 00Z MONDAY/

Issued at 707 PM EDT Sat Sep 26 2026

VFR expected with light winds between N and NE for this evening. Sunday morning, especially between 09 and 13 Z, will be the next possibility for fog. Similar to Saturday morning, when LAN had vicinity fog and there was some river valley fog just northeast of GRR, areas of fog may develop, perhaps becoming locally dense to 1/2SM or less.

Moisture below 500 feet is expected to flow from Lake Huron this evening toward LAN and may approach GRR, BTL, and JXN by early morning. Initially 10-15 knot winds a few hundred feet above ground for the first part of tonight may weaken prior to sunrise and allow fog to develop. The REFS is going for about a 70 percent chance of IFR vis at LAN, slightly higher than what it had for yesterday's setup. It also has about a 50 percent chance of IFR at JXN, a 40 percent chance at GRR and BTL, and a 30 percent chance at AZO.

MARINE

Issued at 225 PM EDT Sat Sep 26 2026

Tranquil conditions continue with low wave heights and light easterly winds. Winds will become more onshore each afternoon as the lake breeze develops. Winds turn to the southwest Tuesday then turn to the northwest Thursday night behind the front. Winds and waves may approach Small Craft Advisory criteria at times Wednesday into Friday.

GRR WATCHES/WARNINGS/ADVISORIES

MI...None. MARINE...None.