697
FXUS63 KGRR 092347
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
747 PM EDT Wed Sep 9 2026
.KEY MESSAGES...
- Showers and Storms End This Afternoon/Evening
- Low Chance Of Weekend Rain
- Additional showers and storms Monday/Tuesday
&&
.DISCUSSION...
Issued at 230 PM EDT Wed Sep 9 2026
- Showers and Storms End This Afternoon/Evening
Radar shows ongoing showers shifting to the south/east ahead of a
cold front expected to pass in the coming hours. The passage of this
front will cause showers and storms to come to an end. HREF mean
SBCAPE shows a few hundred joules through the afternoon which
supports isolated thunderstorm potential until precipitation clears
the area.
- Low Chance Of Weekend Rain
Our next chance of precipitation arrives over the weekend as a cold
front and weak shortwave cross the area. Weak moisture return is
expected to keep much of the weekend dry and PoPs low. For those
that see precipitation, amounts should be less than 0.10".
- Additional showers and storms Monday/Tuesday
A stronger system takes aim at the region Monday as the upper-level
jet moves south into the region. A deepening low associated with
this will lead to potentially breezy conditions as well as the
chance for showers and storms. NBM probabilities suggest a 30-40%
chance of over 1" of rainfall, highest across the northwest CWA, so
will need to monitor for potential heavy rainfall. Given a modeled
ample LLJ in place, even with questions on available instability,
we`ll have to monitor potential for storm development.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 747 PM EDT Wed Sep 9 2026
Scattered to broken clouds at 2,000 feet may persist for the next
couple hours but should dissipate as drier air flows in. Kept the
potential for IFR visibility with mist or patchy fog Thursday
morning, as skies partially clear out and surface winds go light.
The consensus of short-term models favor some reduced visibility
vicinity and E, SE, and S of GRR affecting most of the TAF sites.
However, some factors potentially inhibiting fog include drier
low-level air flowing in with 15-20 knots of wind at 500 feet,
though some models relax those winds slightly just prior to
sunrise.
&&
.MARINE...
Issued at 230 PM EDT Wed Sep 9 2026
Observations suggest the Small Craft Advisory/Beach Hazards
Statement may be underperforming a bit bit given webcams do show
some elevated waves will let the headlines ride until expiration
this evening. Another Small Craft Advisory may ne needed Saturday
associated with a cold frontal passage.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement until 8 PM EDT this evening for MIZ037-
043-050-056-064-071.
MARINE...Small Craft Advisory until 8 PM EDT this evening for LMZ844>849.
&&
$$
DISCUSSION...Thomas
AVIATION...CAS
MARINE...Thomas
NWS GRR Office Area Forecast Discussion
