990
FXUS63 KGRR 031045
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
645 AM EDT Mon Aug 3 2026
.KEY MESSAGES...
- Mostly Sunny into Tuesday
- Showers and Thunderstorms Possible Tuesday Night into Friday
&&
.DISCUSSION...
Issued at 210 AM EDT Mon Aug 3 2026
- Mostly Sunny into Tuesday
Pressure heights increase as the mid level ridge moves overhead
along with the surface high. Mostly sunny skies and light winds
are expected. A lake breeze develops this afternoon with westerly
winds pushing inland. Winds will be more southwesterly Tuesday
ahead of our next chance for rain.
Highs in the mid 70s to mid 80s are expected with lows in the 50s
with a couple spots north of US-10 potentially dropping into the
upper 40s.
- Showers and Thunderstorms Possible Tuesday Night into Friday
A broad upper level trough moves in mid week with heights
beginning to lower Tuesday night. Overall showers Tuesday night
may remain just north and west of the forecast area until better
forcing and moisture moves in Wednesday morning. The trough axis
and surface front will be slow moving in and out of the area. A
lull in showers is possible Wednesday afternoon before another
round of positive vorticity advection moves through Wednesday
night into Thursday morning. Instability is limited, mean values
around 500 J/kg or less, and shear is weak. Therefore the
potential for severe thunderstorms is low. Dry conditions slowly
move in Thursday night into Friday behind the front.
There is the potential for shower and thunderstorm chances to
linger into the weekend looking at ensembles. Within the broad
trough in southwest to west flow we do not clear out the
instability and moisture in the area. However confidence is not
high enough to add PoPs into the forecast this far out. With no
significant source of lift, most if not all could remain dry.
Temperatures will continue to be in the 70s to 80s during the day
with overnight lows in the 50s and 60s.
&&
.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 645 AM EDT Mon Aug 3 2026
Shallow ground fog is impacting the area and reducing
visibilities this morning. With the patchy and shallow nature of
the fog, it should burn off quickly this morning.
Light and variable winds are expected throughout the day. A lake
breeze develops this afternoon with west winds pushing further
east into western Michigan. Some diurnal cumulus around 3500 to
4500 feet is expected today.
Another round of shallow ground fog is possible again tonight into
Tuesday morning.
&&
.MARINE...
Issued at 210 AM EDT Mon Aug 3 2026
The South Haven buoy wave height readings continue to fall as
winds become light and variable. With waves now below 4 feet and
falling to around 1 foot this morning have cancelled the Small
Craft Advisory and Beach Hazard Statement.
High pressure will bring light winds and low wave heights into
Tuesday. Water temperatures will be in the 50s with some spots in
the 40s. Winds then shift to the southwest Tuesday and may
approach Small Craft Advisory thresholds north of Grand Haven with
wave heights 1 to 3 feet. Winds and waves are then expected to
remain below Small Craft Advisory and Beach Hazard Statement
levels through the rest of the week.
Thunderstorms are possible late Tuesday night into Thursday. The
threat for severe storms is low.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.
&&
$$
DISCUSSION...RAH
AVIATION...RAH
MARINE...RAH
NWS GRR Office Area Forecast Discussion
