820
FXUS63 KGRR 091748
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
148 PM EDT Thu Oct 9 2025

.KEY MESSAGES...

- Areas of Frost Possible Again Tonight

- Periods of Rain Friday through Saturday

&&

.DISCUSSION...
Issued at 340 AM EDT Thu Oct 9 2025

- Areas of Frost Possible Again Tonight

Temperatures are currently in the upper 20s to low 40s across the
area and expected to drop into the mid 20s to mid 30s by sunrise.
This will result in scattered to widespread frost across the area.

Tonight 925 mb temperatures are a little warmer and winds won`t be
as calm which may limit the frost potential. Cloud cover will also
be increasing toward Friday morning. Currently areas mainly east
of 131 drop into the mid 30s tonight into Friday morning, but
these temperatures may need to be adjusted a few degrees warmer if
the factors mentioned increase.

- Periods of Rain Friday through Saturday

An upper level low swings through the area Friday afternoon and
evening bringing a round of rain to the area ahead and along the
cold front. Along with the rain breezy southwest winds are
expected ahead of the front gusting around 20 to 30 mph. Behind
the front northwest winds remain elevated mainly along the
lakeshore.

The upper level low then sits overhead continuing lift with the
vorticity maximum and frontogenesis. Pockets of drier air are
possible looking at the low to mid level moisture profiles
resulting in dry breaks. As the low lifts to the east Saturday
night into Sunday dry weather returns. 10th percentile (low end
amounts) range in a trace to around a tenth of an inch of rain
while the 90th percentile ( high end amounts) are around a tenth
to a half inch of rain. These higher amounts will depend on where
the best moisture sets up and remains over the longest.

Guidance varies going into next week with a ridge to the south and
a low to the north. Depending on the strength of either of these
features will determine our rain chances for the remainder of the
week. At this time NBM PoPs show a mostly dry forecast with 20
percent pops clipping the area Monday, Wednesday and Thursday,
but there is still time for the forecast to change given the
variabilities in the low to the north and high pressure to the
south.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 147 PM EDT Thu Oct 9 2025

High pressure sliding slowly away to the east of the Great Lakes
this afternoon and tonight will maintain a hold on our weather.
The high will provide light winds and mainly clear skies. Bottom
line, VFR weather is expected to continue this afternoon through
Friday morning. A cold front will approach the area from the
northwest Friday morning and by late in the TAF period, 15z to
18z, we will see VFR ceilings push into MKG. Not out of the realm
of possibilities to see an isolated light rain shower near MKG
16z-18z on Friday. Winds will be light out of the east and
southeast today at 5-10 knots. Winds will increase Friday after
14z out of the south at 10-20 knots.

&&

.MARINE...
Issued at 340 AM EDT Thu Oct 9 2025

East to southeast winds around 5 to 15 knots are expected today
then shift to the southwest Friday ahead of an approaching front.
Small Craft Advisory winds are expected to develop Friday morning
with gusts to 30 knots and waves building to 4 to 9 feet. Winds
shift to the northwest behind the front continuing Small Craft
Advisory conditions into Saturday morning before waves subside.
Offshore winds return Sunday and continue into the beginning of
next week.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Frost Advisory from midnight tonight to 9 AM EDT Friday for
     MIZ038>040-045-046-051-052-058-059-066-067-073-074.
MARINE...None.

&&

$$

DISCUSSION...RAH
AVIATION...Duke
MARINE...RAH