textproduct: Grand Rapids

KEY MESSAGES

- Frost and Freeze Conditions Tonight

- Clipper System Moves Through Tuesday

- Warmer with Showers and Storms Late Week and into the Weekend

DISCUSSION

Issued at 257 PM EDT Mon May 11 2026

- Frost and Freeze Conditions Tonight

Another night of frost and freeze conditions tonight as high pressure slides through the Lower Peninsula. Low temperatures tonight will dip in most areas to between 30 and 37 degrees. Lows will likely be obtained around 400am as winds increase after that time and especially towards daybreak. High clouds also advance in late which should dampen the slide in temperatures. Frost Advisory for the bulk of the area, with a Freeze Warning for Mason, Oceana, Osceola, Clare, Mecosta and Isabella counties.

- Clipper System Moves Through Tuesday

A clipper system will slide through the area on Tuesday. Rainfall with the system in many areas will likely be between 0.10 and 0.25 inches according to the HREF. A few swaths between 0.25 and 0.50 are possible as well. A fairly light rain overall for the midwest in spring time. Instability is quite marginal, on the order of a few hundred j/kg, therefore not expecting much in the way of convection. Looking at the HREF 4hr max reflectivity however it does appear that at least some isolated storms are possible between 7pm and midnight associated with the cold frontal passage. Not expecting much in the way of severe weather given the poor/low instability. That said, there is some DCAPE (500-600 j/kg) and a somewhat dry subcloud layer so cannot rule out some potential wind gusts to 40+ mph.

- Warmer with Showers and Storms Late Week and into the Weekend

The pattern shifts late this week and into the weekend as the upper pattern goes first more zonal and then southwest. Multiple rounds of showers and thunderstorms look likely as the pattern shifts. The time frames of higher likelihood of precipitation looks to be Friday and again Monday and Tuesday tied to stronger upper shortwaves.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 151 PM EDT Mon May 11 2026

There is very high confidence (95 percent chance) for VFR conditions to persist at all terminals through 06Z. After 06Z, some model guidance (such as NBH hourly text bulletins) hints at ceilings in the 3000-4000 ft AGL range spreading into the area from west to east around or shortly after 12Z. Other guidance is more in the 8000 foot range. Precipitation could be entering the area by the valid end time of this TAF package, but will wait for the 00Z cycle to provide more detail.

MARINE

Issued at 257 PM EDT Mon May 11 2026

Winds and waves will be on the increase on Tuesday as southerly winds ramp up to 30 knots. We could see some gale force gusts Tuesday afternoon and evening. The wind and the resultant waves are due to a strong pressure gradient between a 1025mb departing high and an incoming clipper system with a depth to around 1004mb. Waves will likely reach the 3 to 6 foot range. We will need to continue the SCA into Wednesday most likely in the northwest flow behind the clipper system.

Winds and waves will come up a bit this afternoon and evening in an advancing high type of event where the localized pressure gradient is maximized at peak heating. We do not feel this event will last very long or peak at SCA levels for very long to warrant a headline.

GRR WATCHES/WARNINGS/ADVISORIES

MI...Freeze Warning from midnight tonight to 8 AM EDT Tuesday for MIZ037>040-045-046. Frost Advisory from midnight tonight to 8 AM EDT Tuesday for MIZ043-044-050>052-056>059-064>067-071>074. MARINE...Small Craft Advisory from 8 AM Tuesday to 8 AM EDT Wednesday for LMZ844>849.