642
FXUS63 KGRR 291811
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
211 PM EDT Fri Aug 29 2025

.KEY MESSAGES...

- Sunny Through Early Next Week and Warming

- Cool and Wet Mid Next Week

&&

.DISCUSSION...
Issued at 210 PM EDT Fri Aug 29 2025

- Sunny Through Early Next Week and Warming

The arrival of surface high pressure and a very dry moisture profile
aloft will keep skies mostly cloud free this weekend. Tonight will
feature very favorable radiational cooling conditions as winds calm
and skies remain clear. Expect that similar to last night,
temperatures across our typical cold spots will fall notably lower
than guidance. Will go with a Frost Advisory across Clare and
Osceola Counties as its likely that temperatures will at least get
down into the mid 30s, particularly in the normal cold spots.
Highs will be in the mid 70s Saturday and upper 70s Sunday as the
trough pulls away.

A brief period of ridging then arrives early next week as 850 mb
temps climb into the low to mid teens. This will translate to highs
around 80 for Monday and Tuesday. A continued dry airmass and high
pressure will keep sunshine plentiful.

- Cool and Wet Mid Next Week

Conditions change into Wednesday and Thursday as large scale
troughing returns to the region. This will be an anomalous trough
for this time of year with 500 mb heights approaching 4 standard
deviations below normal. This will bring cool conditions back to
West Michigan. This trough will also drive a low pressure system and
associated cold front through the region Wednesday bringing showers,
and possibly some thunder Wednesday afternoon. 850 mb temps fall
back into the single digits behind this front bringing lake effect
rain showers back into the forecast Thursday into Friday.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 148 PM EDT Fri Aug 29 2025

VFR prevails the rest of the day with scattered to broken cumulus
clouds around 3,500 to 4,500 feet through sunset. Light and
variable winds overnight, perhaps with patchy or shallow fog
developing in some spots before sunrise.

&&

.MARINE...
Issued at 210 PM EDT Fri Aug 29 2025

Light winds and low waves expected through the holiday weekend, with
wind direction changes mostly governed by a daytime lake breeze and
nighttime land breeze. Water temperatures are in the mid 50s to mid
60s after upwelling created by recent north-northeast winds.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Frost Advisory from 2 AM to 8 AM EDT Saturday for MIZ039-040.
MARINE...None.

&&

$$

DISCUSSION...Thomas
AVIATION...CAS
MARINE...CAS