textproduct: Grand Rapids

KEY MESSAGES

- Showers ending Sunday

- Dry early next week, then chances for rain.

DISCUSSION

Issued at 312 AM EDT Sat Aug 1 2026

- Showers ending Sunday

Regional radar shows a large area of showers over the cwa extending south to the Tennessee Valley. No big changes to the forecast planned for today.

A slow moving low pressure system over central IL will continue to produce light to occasionally moderate rain today, tonight and ending from northwest to southeast Sunday. Instability isn't high, but there is enough SBCAPE to keep the mention of thunder in the forecast. Precipitable water values remain somewhat high...around 1.75 inches, which suggests that a stronger shower or storm could produce heavy rainfall; the far southern cwa remains in a slight risk for excessive rainfall. Overall, basin QPF ranges from a third to around an inch. Thus, while there may be localized flooding, widespread river flooding isn't expected. Heaviest rainfall will occur this afternoon as deformation forcing develops.

The upper trough axis will pass through the cwa Sunday morning, which should push the precipitation east; much of the cwa will be dry by Sunday afternoon.

- Dry early next week, then chances for rain.

High pressure will begin building into the region Sunday night and continue through Tuesday; we'll be dry through that time period. Highs will be in the mid 80s and lows in the mid to upper 50s; dewpoints will also be in the 50s. Thus, lower humidity is expected early in the week.

Troughing then develops late in the week and we could see several low chances for additional precipitation.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 629 AM EDT Sat Aug 1 2026

Regional radar shows light rain showers over the region with steadier rainfall near US-10. We'll continue to see showers move in from the south as low pressure moves across IL/IN today and tonight. A rumble of thunder is not out of the question at the I-94 terminals, but confidence wasn't high enough to include in the TAFs.

Ceilings will eventually fall to MVFR late this afternoon and then IFR tonight as the upper trough approaches.

MARINE

Issued at 312 AM EDT Sat Aug 1 2026

Northeast winds will increase to 15 to 20 knots today resulting in highest waves near the 5 mile point offshore. Winds increase a bit to 15 to 25 knots tonight and a small craft advisory may be needed. Otherwise, chances for thunderstorms, while not zero, are minimal given the best instability with this system remains south of the lake.

Waves are likely to increase again Sunday afternoon as high pressure builds over the Great Lakes and an advisory may be needed then too.

GRR WATCHES/WARNINGS/ADVISORIES

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