569
FXUS63 KGRR 111051
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
651 AM EDT Fri Sep 11 2026
.KEY MESSAGES...
- Low chance of Rain on Saturday
- Showers and Thunderstorms Possible Late Monday into Tuesday
&&
.DISCUSSION...
Issued at 138 AM EDT Fri Sep 11 2026
- Low chance of Rain on Saturday
Surface high pressure moves east on Saturday and return flow
brings some moisture. There could be a few showers on Saturday
and Saturday night. There is enough ensemble support to bump up
NBM POPs from around zero to slight/low chance across the northern
zones where the better moisture and lift is located.
- Showers and Thunderstorms Possible Late Monday into Tuesday
A shortwave trough ejects out of the northern Rockies with a
surface low tracking into Canada early next week. A trailing cold
front is expected to touch off showers and thunderstorms Monday
night and Tuesday. Instability and deeper moisture is across
northern Lower Michigan pooling ahead of the cold front, which
sinks south through the forecast area on Tuesday. Precipitable
water surges close 2 inches, so heavy rain potential is there as
the front will be moving slowly and MBE vectors are less than 10
knots.
The front stalls across the southern zones on Wednesday, with a
rainy stretch of weather possible through Thursday as a surface
low tracks along the front across southern Lower Michigan.
&&
.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 650 AM EDT Fri Sep 11 2026
Any shallow ground fog will be dissipating early this morning
then VFR conditions will prevail through tonight.
&&
.MARINE...
Issued at 138 AM EDT Fri Sep 11 2026
Winds and waves will increase Saturday ahead of a cold front and
a Small Craft Advisory may be needed. Stronger winds are expected
early next week and gales are possible by Monday night and
Tuesday.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.
&&
$$
DISCUSSION...Ostuno
AVIATION...Ostuno
MARINE...Ostuno
NWS GRR Office Area Forecast Discussion
