193
FXUS63 KGRR 222344
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
744 PM EDT Sat Aug 22 2026
.KEY MESSAGES...
- Scattered Showers and Thunderstorms this Afternoon
- Cooler with Slight Chances (20 percent) for Showers Sunday
- Midweek Rain Chances
&&
.DISCUSSION...
Issued at 200 PM EDT Sat Aug 22 2026
- Scattered Showers and Thunderstorms this Afternoon
The upper level trough will continue to move through lower Michigan
today. The front is currently around a Midland to Battle Creek
line and shifting east. Expect isolated to scattered showers and
thunderstorms along and ahead of the front before it clears later
this afternoon. We`ll still be under the upper level trough until
tonight with some positive vorticity advection moving through the
flow. Moisture is limited, but can`t rule out an isolated shower
this evening. Northwest winds pick up behind the front with gusts
around 20 to 30 mph before the inversion builds in this evening.
Warmer lake temperatures with dropping 850mb temperatures may keep
the air mass unstable enough along the lakeshore for some spotty
showers into early Sunday (20 percent chance).
- Cooler with Slight Chances (20 percent) for Showers Sunday
The upper level low will remain over the eastern Great Lakes
continuing some slight chances (20 percent) in the northwest flow.
Another surge of positive vorticity advection is expected to move
through the afternoon which could add additional support for shower
development along with some diurnal shallow instability. The best
chances will be north of I-96 and taper off Sunday evening.
Northwest winds will continue to be breezy with gusts to 30 mph
during the day. Temperatures will be a little cooler than today with
highs in the upper 60s to low 70s.
- Midweek Rain Chances
A shortwave ridge moves in for the beginning of next week but it
will be short lived. Heights begin to fall with the approaching
trough Wednesday into Thursday. Warm air advection may spark off
showers and thunderstorms late Tuesday night into Wednesday morning,
otherwise the best chances (50 to 70 percent) hold off until
Wednesday night when the trough axis is expected to move through. A
lull is possible Thursday morning before chances increase (30 to 50
percent) again with the daytime heating Thursday afternoon.
Monday will be the coolest day of next week with highs in the 70s.
Temperatures then warm into the low 80s for the rest of the week.
Low temperatures will largely be in the 50s with some spots dropping
into the 40s Monday and Tuesday morning.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 740 PM EDT Sat Aug 22 2026
Pesky/stubborn showers and thunderstorms continue across parts of West
Michigan early this evening, as cooler air aloft slowly works
into the region. TAFs will support a risk for convection through
01-02Z at LAN and MKG, though restrictions should be limited.
With setting sun, lingering clouds /should/ diminish with clear
to partly cloudy skies /VFR WX/ for the duration of the night. NW
wind gusts to around 20 kt at 00Z will also quickly diminish.
Caveat to tonights quiet weather... and as previously discussed,
with 850 mb temps falling to 7-8C and water temperatures of
+21-22C, influence of Lake Michigan will need to be monitored
overnight, especially at MKG. Some lake clouds and even a pop up
lake effect shower will be possible overnight, but is not
reflected in any TAFs at this time.
With much cooler air aloft, expect an uptick in CU /3-5kft/ after
14-15Z Sunday areawide, and NW wind gusts of 20-25 kt will develop
after 14-15Z.
&&
.MARINE...
Issued at 200 PM EDT Sat Aug 22 2026
High Swim Risk and Small Craft Advisory conditions continue through
Sunday. Northwest winds with gusts to 30 knots will cause waves to
continue to build into Sunday with wave heights peaking around 5 to
7 feet Sunday afternoon. Waterspouts will also be possible tonight
into early Sunday morning with the best chances toward southern Lake
Michigan.
Winds and waves slowly come down Sunday night into Monday. Another
period of Small Craft Advisory and High Swim Risk conditions is
possible Wednesday along with our next chance for showers and
thunderstorms.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement through Sunday evening for MIZ037-043-
050-056-064-071.
MARINE...Small Craft Advisory until 11 PM EDT Sunday for LMZ844>849.
&&
$$
DISCUSSION...RAH
AVIATION...Smith
MARINE...RAH
NWS GRR Office Area Forecast Discussion
