277
FXUS63 KGRR 050755
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
355 AM EDT Fri Sep 5 2025

.KEY MESSAGES...

- Strong winds with cold frontal passage today

- Cooler period through the weekend due to successive fronts

- Return to normal temps next week

&&

.DISCUSSION...
Issued at 350 AM EDT Fri Sep 5 2025

- Strong winds with cold frontal passage today

 Gusty winds are expected across Michigan today. The strongest
gusts will be along the lakeshore, especially north of the I 96
corridor. A swath of winds from a low level jet will make its way
across the state along the cold front. Currently the front is
moving on shore with winds of 38 mph is along the lake shore.
Can`t rule out isolated gusts upwards of 40 mph, especially along
the lakeshore. However, not expecting it to be widespread or long
lived. Strongest winds will be this morning and weakening after 11
AM.
 While there remains a 50 kt LLJ at 850mb the question is whether
that will mix to the surface. While there is cold air along with
this system, there remains question on if it will mix to the sfc.
DCAPE remains strongest further north but only 300 J/kg. So not
the best forcing. However 0-3KM shear is upwards of 40kts. so
given rain loading with frontal passage a brief period of wind
gusts upwards of 40 to 45 mph is possible.

- Cooler period through the weekend due to successive fronts

While Gusty winds will continue through the morning the regions
weather will be dominated by a large upper level low over southern
Canada. As that low moves eastward, successive troughs will filter
through bringing chances for showers Saturday and Sunday. The
limiting condition will drier air just south of the trough which
will limit QPF. Temps will be 10 to 15 degrees below normal with
highs in the 60s

- Return to normal temps next week

 As the upper level low moves eastward and flattens,
temperatures will increase into next week with temperatures
returning closer to normal with another chance for precipitation
Tuesday into Wednesday.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 158 AM EDT Fri Sep 5 2025

Biggest aviation concern overnight will be the front. Expect wind
shear between 08Z to 14Z west to east. There is some concern that
some of these higher winds will mix to the surface. However, given
the uncertainty have left wind gusts at 30kts.
 A period of MVFR cigs is possible at MKG mid to late morning.
Gusty winds will continue through this afternoon and early
evening before diminishing this evening.

&&

.MARINE...
Issued at 322 AM EDT Fri Sep 5 2025

Dangerous winds and waves will continue today into Saturday
Gales of 40kts or higher are expected for all marine zones
are expected this morning with waves of more than 10 feet
expected at times. Muskegon GLERL has reached 38 kts with Big
Sable Ob at 40 kts.  Some improvement in conditions late Friday
but hazardous winds and waves to small craft and swimmers should
persist into Saturday.


&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement through Saturday morning for MIZ037-043-
     050-056-064-071.
MARINE...Gale Warning until 11 AM EDT this morning for LMZ844>849.

&&

$$

DISCUSSION...Ceru
AVIATION...Ceru
MARINE...Ceru