858
FXUS63 KGRR 081913
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
313 PM EDT Wed Oct 8 2025

.KEY MESSAGES...

- Widespread Frost/Freeze Tonight

- Clouds and Showers Friday and Saturday

- Drying Out Early Next Week

&&

.DISCUSSION...
Issued at 311 PM EDT Wed Oct 8 2025

- Widespread Frost/Freeze Tonight

The primary concern in the near term is for widespread frost/freeze
to develop overnight as skies are clear overnight with near calm
winds being favorable for radiational cooling. The coldest temps
will be across our northeast CWA in the primary cold hollows.
However, NBM guidance gives much of the US127 corridor and adjacent
areas a 70% or greater chance of temperatures falling below 32F
overnight. Have issued a Freeze Warning to cover these areas
accordingly. For areas south of I96 and near/west of US131, a slight
southerly component to the light winds will support slightly higher
temperatures in the mid 30s. A Frost Advisory has been issued for
these areas.

- Clouds and Showers Friday and Saturday

Clouds and showers arrive later Friday and continue into Saturday as
a mid-level shortwave arrives to the region. This wave will cutoff
from the main flow pattern Friday and drift southeast over the
following day or two. The NBM and global ensembles are pretty
bearish on QPF with most of the area seeing under 0.1". Given the
expectation for mid-level moisture to be marginal this is
reasonable.

- Drying Out Early Next Week

Large scale ridging takes over as we get into Sunday and continues
into Monday/Tuesday. Combined with the influence of a strong
Canadian High invof the Great Lakes this will keep conditions dry.
As this happens, high temperatures will begin to climb back into the
upper 60s/the 70s.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 155 PM EDT Wed Oct 8 2025

No aviation concerns the next 24 hours with VFR conditions
forecast throughout the TAF period. Skies will be mainly clear
the remainder of the day. We will see some scattered cumulus
clouds drift into places like MKG and GRR, but bases will be
around 5,000 feet. Clear skies will continue overnight, but there
may be some scattered cumulus off of Lake Huron that makes it into
LAN. Bases will again be VFR if we see those clouds at all. Winds
will be north around 10 knots this afternoon becoming light and
variable overnight.

&&

.MARINE...
Issued at 311 PM EDT Wed Oct 8 2025

High pressure will bring lighter winds and low wave heights tonight,
Thursday and into Thursday evening. Through Thursday evening winds
will generally be less than 10 knots with waves of 2 feet or less.
The exception is this afternoon we will continue to see winds gust
into the 10-20 knot range. These winds will taper off considerably
around sunset.

The time frame of concern begins overnight Thursday night lasting
through Friday and into Friday evening. The pressure gradient
tightens between a departing high (1033mb) moving off the east coast
at 15Z on Friday and a low (1010mb) moving into Western Lake
Superior. South winds to 30 knots looks very likely due to the
pressure gradient over Lake Michigan. Current thinking is we will
remain below Gale. 3-5 footers are likely by Friday at daybreak
north of Grand Haven. Waves will likely peak in the same area, 4-7
feet, at midday on Friday. Given this is a fourth period headline
for the most part will hold off for now, but subsequent shifts will
likely be looking at a Small Craft Advisory.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Freeze Warning from midnight tonight to 9 AM EDT Thursday for
     MIZ037>040-043>046-051-052-058-059-066-067-073-074.
     Frost Advisory from midnight tonight to 9 AM EDT Thursday for
     MIZ050-056-057-064-065-071-072.
MARINE...None.

&&

$$

DISCUSSION...Thomas
AVIATION...Duke
MARINE...Duke