208
FXUS63 KGRR 041143
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
743 AM EDT Wed Jun 4 2025

.KEY MESSAGES...

- Rain and Thunderstorms through Tonight

- Mostly Dry Conditions Thursday through Saturday

- Another Round of Rain and Thunderstorms Sunday into Monday

&&

.DISCUSSION...
Issued at 310 AM EDT Wed Jun 4 2025

- Rain and Thunderstorms through Tonight

With the lack of instability and warming clouds seen on satellite
we are looking at scattered showers overnight northwest of Grand
Rapids. The focus for showers is along the front currently
stretching from southeast Wisconsin into the northwest Lower
Peninsula. Plenty of low level frontogenesis along the front with
precipitable water values around 1.7 inches. Some additional
support for shower development is that the right entrance region
of the upper level jet is positioned over the western Great
Lakes.

As the front slowly shifts east so will the band of rain. At this
time rain moves into the Grand Rapids area after sunrise and
toward Lansing and Jackson during the late morning and afternoon.
With the slow progression areas ahead of the rainfall will see
instability build with the HREF showing mean MUCAPE values around
1000 J/kg toward Jackson. The instability paired with 40 to 50
knots of shear will support the potential for some stronger storms.
Wind and hail would be the main risks with hail being more
possible with any isolated storms that develop ahead of the main
line.

By late afternoon early evening the front stalls around the
Jackson area where additional showers and storms remain possible
into Thursday morning.

- Mostly Dry Conditions Thursday through Saturday

Most remain dry Thursday with the remnants of the washed out front
lingering near Jackson and Ingham counties. Along this washed out
front showers and storms remain possible. NBM probabilities of a
hundredth or more highlight 20 percent chances along and east of
a Battle Creek to Lansing line and 40 to 50 percent across the
southeast half of Jackson County.

Weak high pressure moves in behind the front. A slight shortwave
trough may spark some showers Friday afternoon and evening,
although probabilities are less than 20 percent in the ENS and
GEPS ensembles. The GEFS ensemble is more aggressive with a 30 to
50 percent chances of a hundredth or more or rain during Friday
afternoon and evening. With this will keep the 20 percent PoPs
from the NBM.

The backside of the shortwave trough moves through Saturday
morning with dry conditions likely. Temperatures during this
stretch will be seasonable with highs in the 70s and lows in the
50s.

- Another Round of Rain and Thunderstorms Sunday into Monday

Ensembles are in agreement of a cut off low moving into the Great
Lakes region Sunday into Monday. Best chances for rain (50 to 60
percent) are during the afternoon and evening Sunday. It does look
like we`ll have some instability available as well, so a few
rumbles of thunder will be possible. The low lingers over the
Great Lake region into next week continuing light shower chances
through Monday.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 743 AM EDT Wed Jun 4 2025

Rainfall with the cold front is gradually moving through the area.
Expect reduced visibilities and ceilings gradually lowering to
MVFR and IFR values. Southwest winds gusting 20 to 25 knots are
also expected ahead of the front and rain. Thunderstorms will be
possible later this morning into the afternoon with the best
chances toward LAN and JXN. Isolated stronger storms remain
possible with the risk for strong winds.

Northwest winds move in behind the front with ceilings slowly
lifting into Thursday morning. Rain showers could linger toward
JXN into Thursday.

&&

.MARINE...
Issued at 310 AM EDT Wed Jun 4 2025

Southwest winds with gusts to 30 knots continue until the front
moves through overnight into Wednesday morning. Lighter northwest
winds will cause waves to subside below Small Craft Advisory
levels around mid morning. A weak pressure gradient will remain in
place through the rest of the week with winds and waves expected
to remain below Small Craft Advisory levels.

Waves along Lake Michigan beaches will decrease in height through
the morning and afternoon. A Moderate swim risk is expected today
for beaches mainly north of Holland.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement until 8 AM EDT this morning for MIZ037-
     043-050-056.
MARINE...Small Craft Advisory until 8 AM EDT this morning for LMZ844>849.

&&

$$

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