741 FXUS63 KGRR 041918 AFDGRRArea Forecast Discussion National Weather Service Grand Rapids MI 318 PM EDT Sat Oct 4 2025
.KEY MESSAGES...
- Near-record highs and dangerous swimming conditions through Sunday
- Rain chances and a cooldown arrive Monday and beyond
&&
.DISCUSSION... Issued at 317 PM EDT Sat Oct 4 2025
- Near-record highs and dangerous swimming conditions through Sunday
Our weather pattern continues to be dominated by a large high pressure system centered over the eastern CONUS. Widespread cloudiness is hard to come by around the Great Lakes as strong subsidence continues to keep conditions mostly sunny and dry. Some fair wx cu fields have developed over Indiana, Ohio, and Lower Michigan as of this writing. It`s neat to see the lines of diurnal clouds matching the anti-cyclonic flow pattern that is occuring at the low and mid levels of the atmosphere. An upper low ejecting into the high plains is coincident with a cold front draped across the area and up into Canada... with this whole complex slowly moving eastward. While this will eventually make it to our part of the world, the rest of today and Sunday will feature plenty of sunshine and unseasonably warm temperatures. Most locations in Lower Michigan will be close to record high temperatures both today and again tomorrow, with at least 1 record high (Lansing) having recently occurred. For more info on record highs today and tomorrow, see the climate section below.
Meanwhile, the pressure gradient across Michigan is slowly tightening up, resulting in some gusty south/southwest winds today. This will become even more pronounced tomorrow as the cold front starts to make more progress toward the Great Lakes. With another hot and sunny day on track for tomorrow, beaches will be more popular than normal for October, and swim risks will climb quickly. For more information, see the Marine section below. Another risky element of this unusual weather pattern will be the hot and windy conditions leading to elevated fire danger - which is especially strange considering the time of year. While conditions will not be bad enough to warrant a Red Flag warning, concern is definitely elevated as any fires that do start will have the potential to spread quickly. Please continue to exercise caution with campfires, and as always heed any local burning restrictions.
- Rain chances and a cooldown arrive Monday and beyond
The cold front arrives during the day Monday, bringing a good chance of rain to most of the area along and ahead of the front. With a few hundred joules of MUCAPE in the area, and with decreasing subsidence aloft, several lines of showers and non-severe storms seem likely from Monday afternoon through Tuesday morning. Ensemble guidance shows an approx 30% chance of exceeding 0.50" widespread rain totals, though if some training of thunderstorms can occur some 1-2" rain totals are not impossible. With worsening drought across the area, any rains that we can get will be beneficial.
Temperatures cool down closer to normal with highs in the 60s or low 70s for the midweek and beyond period. Another chance for rain arrives late in the week as the overall flow becomes more zonal - allowing shortwaves to move quickly from west to east, but specific confidence in timing or rain amounts is low. The main takeaway at this point should be that we`ll be moving into a period with better periodic rain chances compared to the dominating blocking high pressure we`ve had for much of the last week.
&&
.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 102 PM EDT Sat Oct 4 2025
High confidence in VFR conditions through the TAF period as dry air is in place. Southwest winds to 10 knots today become southerly and subside to near 5 knots overnight. Increasing gradient winds will lead to southwest winds around 10-15 knots again Sunday. At MKG interaction with the lake will support gusts to around 20 knots in the late morning into the afternoon.
&&
.MARINE... Issued at 317 PM EDT Sat Oct 4 2025
Will be issuing a Small Craft Advisory/Beach Hazards Statement for the late Sunday Morning through early Monday afternoon timeframe. Increasing south to southwest flow will drive gusts to around 25 kts north of South Haven and waves of 3-6 feet north of Holland. Increased concern exists with the well above normal temperatures increasing beach traffic above normal for the time of year given the expectation for dangerous winds and waves. These same temperatures do provide some uncertainty as to how strong will gusts be but with strong gradient winds at minimum waves will be a hazard. Gradient winds decrease into Monday causing a brief period where winds and waves subside. Tuesday into Tuesday Night a period of increasing north winds is expected behind a cold front. This may bring an additional round of hazardous winds and waves, particularly south of Holland.
&&
.CLIMATE... Issued at 317 PM EDT Sat Oct 4 2025
With one record already set (88 in Lansing today sets a new record), more may follow. For reference, here are the established high temperature records across our area for both Saturday and Sunday.
Sat Sun Grand Rapids 87 - 1951 85 - 1946, 1922 Lansing 86 - 1951, 1900 87 - 1922, 1900 Muskegon 84 - 2023 83 - 2007 Kalamazoo 90 - 1951 87 - 1922 Battle Creek 87 - 1951 89 - 1900 Holland 89 - 1951 85 - 2007
&&
.GRR WATCHES/WARNINGS/ADVISORIES... MI...Beach Hazards Statement from Sunday morning through Monday afternoon for MIZ037-043-050-056. MARINE...Small Craft Advisory from 10 AM Sunday to 5 PM EDT Monday for LMZ845>849.
&&
$$
DISCUSSION...AMD AVIATION...Thomas MARINE...Thomas CLIMATE...AMD
NWS GRR Office Area Forecast Discussion