textproduct: Grand Rapids

KEY MESSAGES

- Several Chances For Thunderstorms Tonight Through Monday Night With Severe Weather Possible

- Dry and Cooler Mid to Late Week

DISCUSSION

Issued at 151 PM EDT Sat Jul 25 2026

- Several Chances For Thunderstorms Tonight Through Monday Night With Severe Weather Possible

Bottom line up front. Several chances for strong to severe thunderstorms exist Sunday into Monday Night. However, confidence in timing and coverage of any storms remains low.

First off. a shortwave crosses the area tonight along with placement of LFQ jet forcing. This will bring potential for showers and maybe isolated non-severe storms. Given the dry ambient airmass, coverage will be poor with most areas having a 20% or less chance of rain tonight.

Attention then turns to Sunday afternoon as MLCIN erodes with the arrival of a shortwave and meso-low development across interior MI. Best erosion of MLCIN will be near and east of US-127, however without much in the way of mesoscale forcing, coverage is questionable. In addition, forecast profiles in some short range model guidance show a mid-level cap which would inhibit storm development. However, if storms can develop, shear and instability is sufficient for damaging winds and hail.

Some short range guidance shows the potential for one or more storm clusters to develop in warm air advection Sunday Night/early Monday. If/where this happens is low confidence which is common in "Ring of Fire" scenarios like this. Any storms will be capable of damaging winds and large hail.

The greatest concern for an organized severe weather threat is Monday afternoon/evening as a cold front moves through the area. What occurs as this happens is dependent on if/to what extent we see any morning storms which will affect our ability to destabilize. However, both a strong mid-level jet (with attendant forcing) and an increasing low-level jet in the evening will provide ample low-level and deep layer shear that given sufficient instability, severe weather is possible with any clusters or MCSs that develop. The favored area for this at present is the southern 2/3 of our forecast area. Damaging winds would be the main threat with all hazards possible.

The caveat as alluded to earlier is this is a highly uncertain setup. Where exactly these clusters develop and track is tough to predict more than 12-24 hours out. There are real chances like has happened other days over the last few weeks that storms fail to develop, or that they miss our area keeping us dry. Each subsequent round of storms also depends on what happens with previous storms and any potential boundaries or debris clouds. However, the environment is favorable for storms to be severe if they develop.

- Dry and Cooler Mid to Late Week

Conditions dry out going into Tuesday as the cold front clears the area. Upper-level troughing and surface ridging keeps us a bit cooler as well as dry into Thursday. Precipitation chances then return Friday as a shortwave swings through the area.

AVIATION /00Z TAFS THROUGH 00Z MONDAY/

Issued at 730 PM EDT Sat Jul 25 2026

VFR will continue for most of the TAF period. However, there are caveats. A weak trough will move through early Sunday. While some models have precip, the low levels should be to dry. For the chance of precip at GRR have put in a period of Prob30. There is enough moisture for low clouds between 08Z to around 15Z. This could be enough for MVFR cigs at AZO, BTL, GRR and MKG. There will be a better chance for showers and storms at the tail end of the TAF period and overnight into Monday.

MARINE

Issued at 151 PM EDT Sat Jul 25 2026

Winds climbing to 15-17 kts this afternoon will support 2-4 foot waves, highest north of Grand Haven. Will have to monitor webcams and observations for a brief burst of higher winds to support waves building to 3-5 ft. Best chance for this to occur is near the points if it does occur. Some medium range guidance suggests a similar scenario in southerly flow Monday afternoon ahead of a cold front. Increasing northerly flow behind a cold front Tuesday then makes Small Craft/Beach Hazards winds and waves likely. In addition, several chances for thunderstorms exist Sunday Evening into Monday Night. Locally higher winds (possibly in excess of 34 kts)/waves are possible in any thunderstorms.

GRR WATCHES/WARNINGS/ADVISORIES

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