textproduct: Grand Rapids

KEY MESSAGES

- Cooler Than Normal with Rain Possible Sunday into Monday

DISCUSSION

Issued at 155 PM EDT Thu Jun 18 2026

- Cooler Than Normal with Rain Possible Sunday into Monday

The weather pattern continues to be dominated by zonal flow being steered by a large quasi stationary upper level low situated over central Canada. That low will continue to bring north westerly flow through the region, along with anomalous cold air advection. NAEFS mean temperature anomalies show -1 to -2 standard deviations through the mid levels. That means while the region will see a mix of sun and clouds, the temperatures will struggle to get into the mid 70s. Max temperatures through the weekend and into early next week will be 5 to 10 degrees below normal. Models continue to be in good agreement on the passage of a few weak shortwave traversing the previously mentioned upper level low as it shifts to the south. Those shortwaves will trek through the Great Lake Saturday. This will allow for a chance of precipitation Saturday. Precipitation should be fairly light and will make its way eastward as the day continues. Chances for precipitation of over a tenth are best along the lakeshore Saturday morning. The better chance for heavier precipitation continues to be as a upper level low, currently over the Pacific, filters through the upper level pattern, stamps down a ridge through the intermountain west, and finally makes its way through the midwest. That wave and mid level and surface low will advect good moisture with it. However latest ensembles struggle with its position and track. The best chance for heavy rain remains south of Michigan, though Southern lower could see some rainfall late Sunday into Monday.

AVIATION /00Z TAFS THROUGH 00Z SATURDAY/

Issued at 848 PM EDT Thu Jun 18 2026

VFR weather is in place across all of Southwest Lower Michigan at 00z. That is expected to remain the case through the duration of the forecast period. We do see some upstream clouds and showers working this way from Wisconsin, but we expect showers to dissipate this evening with the setting sun and remain west of the TAF sites. We will see some VFR clouds move in however tonight with bases of 7,000 to 10,000 feet. On Friday we will likely see some fair weather cumulus clouds develop with bases in the 3,500 to 6,000 foot range. Winds have already settled down this evening with the loss of deep mixing. Winds through tonight will be less than 10 knots. Winds will become gusty again on Friday after 15z with 10-20 knots expected and gusts towards 25 knots from the west and northwest.

MARINE

Issued at 155 PM EDT Thu Jun 18 2026

The west to northwest winds continue as advertised. Waves of 3 to 6 feet continue along the lakeshore. The winds will slacken as the day continues and with it the waves will slowly subside. This will occur from the north to the south into Thursday evening. The SCA and Beach hazards will then end accordingly. Winds tomorrow are trending low but there could be a brief period of higher waves, 2 to 4 feet, early in the day.

GRR WATCHES/WARNINGS/ADVISORIES

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