310
FXUS63 KGRR 292343
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
743 PM EDT Tue Sep 29 2026

.KEY MESSAGES...

- Rain Wednesday into Friday

- Cool air follows the rain

&&

.DISCUSSION...
Issued at 252 PM EDT Tue Sep 29 2026

- Rain Wednesday into Friday

An upper low across the western CONUS will move east and pull
moisture from an Eastern Pacific tropical cyclone with it, which
spreads in a narrow ribbon along a nearly-east west frontal
boundary by mid-week. We expect the rain to arrive Wednesday
morning and continue on and off through Friday as the front moves
slowly southeast, nearly parallel with the upper flow. Total QPF
from this event is still expected to be 1 to 2 inches by the time
it ends on Friday, but we will have to watch if it overperforms
from the injection of tropical moisture.

- Cool air follows the rain

Upper troughing follows for the weekend into early next week with
Canadian surface highs bringing the coolest air of the season so
far. Temperatures are expected to fall below normal across the
forecast area with frost and freezing temperatures widespread
Saturday morning and again Tuesday morning as another Canadian
surface high moves south early next.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 743 PM EDT Tue Sep 29 2026

VFR should continue well into tonight, with higher altitude
ceilings trending MVFR from northwest to southeast during the
daytime Wednesday. Not expecting fog tonight given the clouds and
winds below 1,000 feet. The winds at 1,000 feet should be about
200 degrees at 20 to 25 knots, between 03 and 14 Z, which would
lead to there being about 20 knots of LLWS below 1,000 feet. Light
to occasionally moderate rain will spread over much of Lower
Michigan on Wednesday, affecting northwest sooner southeast later.
Ceilings may trend down to IFR near and north/northeast of MKG
Wednesday afternoon.

&&

.MARINE...
Issued at 252 PM EDT Tue Sep 29 2026

No changes to the headlines as winds pick up tonight ahead of the
slow moving front and then ease as the pressure gradient slackens
along the front on Thursday.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement through Thursday morning for MIZ037-043-
     050.
MARINE...Small Craft Advisory until 8 AM EDT Thursday for LMZ847>849.

&&

$$

DISCUSSION...Ostuno
AVIATION...CAS
MARINE...Ostuno