textproduct: Grand Rapids

KEY MESSAGES

- Dry weather tonight and Tuesday

- Multiple chances for showers/storms Tues. night through Sat.

- Seasonable temperatures through the 7 day forecast

DISCUSSION

Issued at 259 PM EDT Mon Aug 3 2026

- Dry weather tonight and Tuesday

High pressure will bring fair weather tonight through Tuesday as high pressure slips away to the southeast of the Great Lakes region. A cooler night than normal for this time of year is expected tonight with lows in the 50s. Highs on Tuesday will reach the middle 80s in most locations.

- Multiple chances for showers/storms Tues. night through Sat.

A surface cold front will push into the area Tuesday night and wash out over Lower Michigan on Tuesday. The weak surface boundary will be a impetus for showers and thunderstorms at times from Tuesday night into Thursday. The pattern will be evolving into a trough over the Great Lakes during this time. Embedded shortwaves within the flow will aid in precipitation production as well. Wednesday through Thursday are the forecast periods where the best chances for rain look to occur. Highest chances for precipitation occur during this time frame 60-70 pct.

Dew points pool along the front rebounding back into the 60s. Most unstable CAPE values push into the 1000-2000 j/kg range. The precipitation looks to be diurnally driven as is usually the case with mid summer upper troughs. Cannot rule out some stronger storms Wednesday afternoon into Wednesday night as the main shortwave moves through combined with 50+ knots in the mid levels at 500mb. At this point we are just in a general thunder outlook from the SPC.

The next time frame of concern is out Saturday night into Sunday with the passage of another upper shortwave. Showers and storms are possible during this time as well. Surface dew points surge into the 70s with the passage for a surface front. Only 20-30 pct pops in the forecast at this point but this will be increased when model continuity increases.

- Seasonable temperatures through the 7 day forecast

850mb temperatures are in the middle to upper teens C which is typical for mid summer. Mid to upper 80s highs are expected for the most part through the period. Low temperatures will be seasonable as well in the mid to upper 60s.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 143 PM EDT Mon Aug 3 2026

Overall VFR conditions will dominate the next 24 hours. Winds remain overall light and variable to calm. There remains the likelihood of a lake breeze developing late today with light to calm winds overnight. Winds are expected to shift to the southwest tomorrow. MVFR vsbys from shallow fog are expected. Brief periods of IFR remain possible between 08Z to 12Z. No precipitation expected in the next 24 hours.

MARINE

Issued at 259 PM EDT Mon Aug 3 2026

Quiet conditions are expected out on the big lake through Tuesday morning. High pressure will slide away to the east tonight which will allow southwest return flow to develop on Tuesday. Light winds are expected tonight with waves 2 feet or less. With the increase in winds on Tuesday, 10-20 knot winds with a few higher gusts are possible up towards Big Sable Point. 4 foot waves only look to impact the far northern marine zone up towards Big Sable for a few hours and only a portion of the zone. So, given marginal conditions will hold off on a Beach Hazards Statement and Small Craft Advisory for now. We will be watching this closely. Southwest winds persist Tuesday night into Wednesday, but conditions will remain below advisory levels.

GRR WATCHES/WARNINGS/ADVISORIES

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