textproduct: Grand Rapids

KEY MESSAGES

- Breezy and warm today into Sunday

- Warm weather through Monday; remnants of Isaias shift east - Pattern change Tues; strong system through latter half of week

DISCUSSION

Issued at 253 AM EDT Sat Oct 10 2026

- Breezy and warm today into Sunday

Warm air advection showers continue to bring light rain early this morning through central lower Michigan. A ridge of high pressure will build over the Great Lakes and southern Canada today as warm air advection continues to stream into the area. As the warm air mixes out the inversion, expect gusty winds, upwards of 25 mph, this afternoon. 850 mb temps of +15C will mix down bringing temps upwards of 15 to 20 degrees above normal, peaking in the upper 70s to potentially the low 80s. - Warm weather daytime Monday; remnants of Isaias shift east The warming trend will continue through Monday. Sunday temps will be slightly cooler due to the cloudy skies from the fringes from the remnants of Isaias. Ensembles continue to shows Isaias track shift to the southeast, with it moving through the Mid Atlantic early Monday. Part of the reason this is occuring is due to a positively tilted ridge that will continue warm air advection that will keep max temperatures 10 to 20 degrees above normal through daytime Monday - Pattern change Tues; strong system through latter half of week Models are showing a flattening of the ridge Monday night into Tuesday with a more zonal upper level flow. Mid to low level low pressure will move through Michigan into Tuesday with a strong moisture boundary extending from New York, through the Great Lakes and into the Upper Mid West. The best moisture late Monday into Tuesday will remain to the north. However, can't rule out some scattered showers Monday night into Tuesday, especially as a deepening trough swings through daytime Tuesday. There should be enough instability for a chance of storms with this system. EC ensembles continue to show strong anomalous moisture Monday night into Tuesday with PWATS of 1.25 to 1.5 inches over the Lower peninsula. Expect a more tumultuous pattern through the latter half of next week. There is some question on timing of the incoming system. Some of the ensembles vary on where the upper level pattern will be. Latest EC trends have backed off on how deep the moisture advects into MI. Though there is a tilted trough that could bring a strong frontal pattern through the end of the week. All that said, there is the potential for showers and storms through the latter half of the week, with the potential for a severe weather event given the strong flow, copious moisture and warm air out ahead of the system.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 126 PM EDT Sat Oct 10 2026

Cloud cover will continue to thicken as the remnants of the tropical system move north toward the Ohio Valley. A LLJ passing to the north early tonight may result in some LLWS. Otherwise, ceilings will continue to fall to MVFR for most terminals and to IFR at BTL and JXN as precipitation gets closer. Light rain is also possible at JXN after 14z.

MARINE

Issued at 253 AM EDT Sat Oct 10 2026

Strong southerly flow will ramp up through Saturday. A small craft advisory will be in effect from Holland and to the north where the best winds and waves will be. The winds will be stronger aloft due to the warm air advection. The gradient will then weaken tonight as Isaias moves through the Ohio Valley and treks through the Mid Atlantic.

The next headline event should occur Monday due to the increasing gradient ahead of the next incoming cold front. A pattern change will allow much of the upcoming week to be windy, especially through the second half of the week due to an incoming low pressure system.

GRR WATCHES/WARNINGS/ADVISORIES

MI...None. MARINE...Small Craft Advisory until 5 AM EDT Sunday for LMZ846>849.