835
FXUS63 KGRR 122357
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
757 PM EDT Sat Jul 12 2025

.KEY MESSAGES...

- Dry Into Next Week

- Next Chance for Rain and Storms Wednesday into Thursday

&&

.DISCUSSION...
Issued at 242 PM EDT Sat Jul 12 2025

- Dry Into Next Week

There is a slight chance (20 percent) for weakening showers and
storms to make it across the lake this evening. Otherwise, dry
conditions are expected into the beginning of next week as we
remain in zonal flow. A brief break in 60 and 70 degree dew points
is expected tomorrow with highs in the low 80s. However, higher
dew points return Monday with hot and humid conditions expected
into Wednesday with heat indices in the upper 80s to mid 90s.

- Next Chance for Rain and Storms Wednesday into Thursday

A series of shortwave troughs move through early Wednesday into
Thursday. Dew points in the upper 60s to low 70s, precipitable
water values approaching 2 inches, and instability paired with
these short waves will bring chances for rain and thunderstorms.
The pattern is a little messy overall with these shortwaves and
the timing of them, therefore it is hard to point out with
certainty any true dry breaks. Additionally the strength of the
trough mid week looks weaker and could be a sign for the severe
weather threat to decrease. We`re still several days out so we`ll
see if this trend continues.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 756 PM EDT Sat Jul 12 2025

VFR should dominate the TAF period. A weak post frontal wave is
moving across the Lake Michigan and there is a small chance it
forms an isolated shower between now and 04Z. However, any showers
that form, should be north of the TAF sites except for perhaps
MKG, and there is enough subsidence so probability is low enough
to not even mention it in an TAF.
 There is a small chance for MVFR cigs/vsbys in patchy fog
overnight, however, the dry air should preclude any formation so
have left it out of TAF`s as well.



&&

.MARINE...
Issued at 242 PM EDT Sat Jul 12 2025

2 to 3 foot wave continue today with southwest winds around 10 to
15 knots with gusts to 20 knots. This will result in low to
moderate swim risk conditions for the remainder of the day.
Lighter westerly winds are expected Sunday with wave heights 0 to
2 feet.

Southwesterly winds build for Monday into Wednesday with wave
heights 1 to 3 feet. Thunderstorms will once again be possible
Wednesday into Thursday.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Air Quality Alert from midnight tonight to noon EDT Monday for
     MIZ037>040-043>046-050>052-056>059-064>067-071>074.
MARINE...None.

&&

$$

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