432
FXUS63 KGRR 310638
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
238 AM EDT Fri Jul 31 2026
.KEY MESSAGES...
- Increasing clouds today. Showers/storms tonight and Saturday.
- Showers middle of next week
&&
.DISCUSSION...
Issued at 238 AM EDT Fri Jul 31 2026
- Increasing clouds today. Showers/storms tonight and Saturday.
IR loop shows abundant high clouds moving over the top of the
ridge and across the state. Clouds will increase today as low
pressure over Iowa strengthens and moves east. Latest models are a
little more bullish on rain chances and amounts across the cwa
tonight and Saturday. The short wave accompanying the surface low
is stronger which in turn is helping to draw moisture northward.
Showers and scattered thunderstorms are expected to develop by
late evening across the western cwa and then move eastward. Given
bulk shear values 20-25kts, severe weather will likely remain
south of the cwa where shear is greater. Locally heavy rainfall
may be a bigger threat.
Precipitable water values increase to over 2 inches after 06z
tonight suggesting that a few of the heavier showers and/or storms
could be prolific rain producers. WPC has painted the cwa in a
slight risk for excessive rainfall for tonight and Saturday. Thus
localized flooding isn`t out of the question. Total qpf from
tonight through Saturday is in the half inch to inch range basin
wide; locally higher.
The low will move east Sunday and rainfall chances will diminish
slowly throughout the day from northwest to southeast.
Clouds and precipitation will hold highs in the mid 70s Saturday
and Sunday.
- Showers middle of next week
Another cold front and upper trough will move across the state
during the middle of next week generating some showers and storms.
Despite the deterministic versions of the ECMWF and GFS being
somewhat out of phase, the ensembles of both show precipitation
during the middle of the week.
Highs will be in the lower to mid 80s through next week.
&&
.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 113 AM EDT Fri Jul 31 2026
IR loop shows broken cirrus spilling over the ridge and down
across the state. We`ll see clouds thicken throughout the day, but
remain VFR. As low pressure approaches late in the day from the
west, showers may develop at the MKG and perhaps GRR prior to 06z,
but the remaining terminals will likely be dry.
&&
.MARINE...
Issued at 238 AM EDT Fri Jul 31 2026
Wind and waves will not pose a threat to small craft today.
However, as low pressure passes to the south Saturday, northeast
winds will increase and a small craft advisory may be needed.
Highest waves Saturday will be closer to the 5 mile point
offshore. Gusty winds will continue into Sunday as high pressure
builds in to the region again.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.
&&
$$
DISCUSSION...04
AVIATION...04
MARINE...04
NWS GRR Office Area Forecast Discussion
