557
FXUS63 KGRR 071927
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
327 PM EDT Tue Oct 7 2025

.KEY MESSAGES...

- Frost/Freeze for Tonight and Wed Night, Chance Frost Thu Night

- A Little Warmer and Mostly Dry Late Week into the Weekend

&&

.DISCUSSION...
Issued at 327 PM EDT Tue Oct 7 2025

- Frost/Freeze for Tonight and Wed Night, Chance Frost Thu Night

Frost and some spots of 2-meter temperatures near 32 are
anticipated tonight in the highlands of interior central Michigan,
mainly northern Newaygo, Mecosta, northwest Isabella counties and
northward. A cooler than average airmass at 850 mb will settle
into the region through Thursday. Mostly clear skies with just a
few patchy clouds are expected tonight, however, light northerly
flow may slow the rate of surface cooling.

High pressure will be more directly centered over Michigan Wed
night, setting up a higher probability of a freeze over much of
Lower Michigan. NBM QMD probabilities for less than 32 degree
temperatures are at least 90 percent for the US-10 area, around 80
percent for the area between Lansing, Marshall, and Jackson, and
at least 50 percent for most of the rest of the area except for
the immediate lakeshore.

Thu night will begin the return of southerly flow and warmer air
as high pressure moves east, though lingering cool air near the
surface under mostly clear skies and light winds may promote frost
over much of the area again.

- A Little Warmer and Mostly Dry Late Week into the Weekend

Temperatures are expected to moderate back to above average by
the weekend, which by this point in the season now means upper 60s
to around 70. About 10 to 20 percent of ensemble members bring a
northern stream shortwave trough down toward Michigan Friday
afternoon or night, which may touch off some light rain showers.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 148 PM EDT Tue Oct 7 2025

IFR to MVFR conditions will gradually lift as the rain shifts east
this afternoon. Light northerly winds and clearing skies are
expected overnight into Wednesday. MKG and other areas along the
lakeshore may briefly gust toward 20 knots tonight around 6Z,
otherwise winds shift to the northeast at around 5 to 10 knots.

&&

.MARINE...
Issued at 148 PM EDT Tue Oct 7 2025

No changes are expected to the Small Craft Advisory for areas
south of Holland. Northerly gusts to 25 knots and wave heights 3
to 5 feet are expected. Further north winds and waves could
briefly approach Small Craft Advisory levels late tonight, but
light northeast winds and falling waves heights are expected by
Wednesday morning. Southerly winds and waves may approach Small
Craft Advisory levels again on Friday. Southeast winds Sunday may
be close to Small Craft Advisory levels as well, but the wind
orientation should help keep waves below criteria with the
highest waves beyond 5 NM.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Frost Advisory from 3 AM to 8 AM EDT Wednesday for MIZ038>040-
     044>046.
MARINE...Small Craft Advisory until 5 AM EDT Wednesday for LMZ844-845.

&&

$$

DISCUSSION...CAS
AVIATION...RAH
MARINE...RAH