174
FXUS63 KGRR 292308
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
708 PM EDT Tue Apr 29 2025

.KEY MESSAGES...

- Frost and Areas of Freezing Temperatures Tonight

- Showers and Storms Wed Night through Thu Night

&&

.DISCUSSION...
Issued at 343 PM EDT Tue Apr 29 2025

- Frost and Areas of Freezing Temperatures Tonight

Temperatures are dropping quickly behind a cold front in
northwestern areas this afternoon. High pressure will move over
Lower Michigan tonight, allowing winds to calm while skies become
mostly clear. We will be starting frost/freeze alerts for our area
up to US-10 (Mason through Clare county) given recent warmth and
the increasing susceptibility of certain plants to freezing
temperatures. Guidance suggests the most likely areas for
widespread freezing temperatures will be from Oceana, Newaygo,
Montcalm, and Gratiot counties to the north. South of there, areas
of frost (and isolated spots of temperatures below 32) are still
expected as 2- meter temperatures drop toward the mid 30s. Local
variability in temperatures will be a factor given the calm winds
leading to colder air settling into the typically colder low
spots.

- Showers and Storms Wed Night through Thu Night

Rounds of rain along with some areas of thunderstorms are likely
between Wednesday night and Thursday night. A good soaking rain is
expected given interquartile QPF from the ENS between 0.75 and
1.25 inches. The upper level shortwave trough responsible for this
will be kicked out of Texas tomorrow ahead of a digging northern
Plains trough. This will bring a good moisture return from the
Gulf along with a deepening low pressure system tracking from
Missouri to Lower Michigan. A warm sector may develop southeast of
Kalamazoo-Lansing Thursday afternoon, along with some surface-
based CAPE although the amount of which is currently questionable.
This may raise some concern for a marginal severe weather threat
given ample low-level shear.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 708 PM EDT Tue Apr 29 2025

Scattered high clouds and a few daytime Cu around 3.5kft will
diminish over the next few hours. Only a few high cirrus are
possible overnight into midday Wednesday with SKC below 25kft
through late morning. Late Wednesday morning high clouds will
thicken with any cigs remaining above 15kft through the end of the
TAF window. West-northwest gusts in excess of 20 knots will
diminish shortly after sunset. Winds will veer to northeasterly
and then southeasterly late this evening with winds overnight into
Wednesday below 10 knots.

&&

.MARINE...
Issued at 343 PM EDT Tue Apr 29 2025

Conditions hazardous to small craft persist through Tue evening
on Lake Michigan. West winds are trending north with cooler air
flowing in. There has been a recent uptick in wind speeds at Big
Sable Point and slight uptick in waves at the Central Lake
Michigan waverider buoy. Conditions have been a bit more tame
farther south at the Port Sheldon and South Haven buoys, but some
gusts to 25 knots remain possible due to the cooler air flowing
in. Waves subside tonight into Wednesday with light offshore
winds.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Freeze Warning from midnight tonight to 8 AM EDT Wednesday for
     MIZ037>040-043>046-051-052.
     Frost Advisory from 2 AM to 8 AM EDT Wednesday for MIZ050-
     056>059-064>067-071>074.
MARINE...Small Craft Advisory until 8 PM EDT this evening for LMZ844>849.

&&

$$

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

NWS GRR Office Area Forecast Discussion