250
FXUS63 KGRR 301142
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
742 AM EDT Sat Aug 30 2025

.KEY MESSAGES...

- Next Chance for Rain late Wednesday

&&

.DISCUSSION...
Issued at 327 AM EDT Sat Aug 30 2025

- Next Chance for Rain late Wednesday

Surface high dominates the Great Lakes through the first half of
next week with upper height rises bringing slowly moderating
temperatures. The warming will be brief however as another upper
low dives southeast from Canada and carves out a longwave trough
across the central and eastern CONUS by late in the week. Moisture
streaming up from the south will converge with the trough axis
and a surface low trailing a cold front by Wednesday night with
showers and a few thunderstorms possible.

Diurnally driven showers with some lake enhancement are possible
on Thursday through the end of the week with shortwave troughs and
vorticity maxima rotating around the upper low in broad cyclonic
flow regime along with steep mid level lapse rates.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 741 AM EDT Sat Aug 30 2025

VFR conditions will prevail through tonight with light and
variable winds.

&&

.MARINE...
Issued at 124 AM EDT Sat Aug 30 2025

Relatively calm conditions expected for the nearshore waters
through early next week as high pressure dominates the Great Lakes
region. Water and air temperatures will remain rather cool for
swimming.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Frost Advisory until 8 AM EDT this morning for MIZ039-040.
MARINE...None.

&&

$$

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