Grand Rapids, Michigan 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

614
FXUS63 KGRR 072324
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
724 PM EDT Mon Jul 7 2025

.KEY MESSAGES...

- Chances for Rain on Wednesday and the Weekend

&&

.DISCUSSION...
Issued at 338 PM EDT Mon Jul 7 2025

- Chances for Rain on Wednesday and the Weekend

A couple shortwaves troughs move through a quasi-zonal flow
regime the next few days bringing the chance for some rain on
Wednesday and again over the weekend.

Severe weather threat is minimal on Wednesday with marginal
instability and deep layer shear of 20 to 25 knots and with the
main batch of showers expected late Tuesday night into Wednesday
morning. Diurnal enhancement of showers is expected Wednesday
afternoon and into early evening. Pulse type storms are possible
with an isolated downburst threat, mostly across the east central
zones where more instability and deeper moisture is forecast to
be.

Shortwave ridging brings mainly dry weather into Friday before the
next trough amplifies across the Northern Plains with ample
moisture return ahead of it. Strong pulse-type storms are
possible by Saturday afternoon with weak/moderate shear profiles
and close to 2000 J/kg CAPE progged by GFS. Showers diminish by
Sunday as drying and subsidence moves in from the west.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 721 PM EDT Mon Jul 7 2025

VFR conditions expected through the TAF period given high pressure
across the region. Moderate (30-40 percent) chance of fog mainly
at JXN where crossover temps are highest. If it does occur,
07z-12z is the favored time. However the presence of mid to high
level clouds has confidence too low to include TAF restrictions at
this time. Lingering scattered clouds below 5kft dissipate shortly
after sunset before mid to high clouds persist through the end of
the TAF window. Light and variable winds tonight increase to 5-10
knots from the west-southwest Tuesday.

&&

.MARINE...
Issued at 338 PM EDT Mon Jul 7 2025

No significant changes to the overall thinking. Increasing winds
along the shoreline will lead to a period of moderate to high swim
risk conditions near and south of Muskegon, particularly for
Ottawa and Muskegon Cos and the adjacent waters. Given observations
currently show at least borderline Beach Hazards/Small Craft
conditions ongoing with the best winds over the next few hours will
keep these hazards as is.

Winds and waves remain below hazardous levels Tuesday. The next
day to watch for potential beach hazards/small craft advisory
level conditions is Wednesday where an approaching high may once
again lead to an increased burst of winds along the lakeshore in
the afternoon. This potential will become clearer in the next day
or so as we move into short range model territory but is already
being hinted at in the NAMNEST and FV3.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement until 10 PM EDT this evening for MIZ050-
     056-064-071.
MARINE...Small Craft Advisory until 10 PM EDT this evening for LMZ844>847.

&&

$$

DISCUSSION...Ostuno
AVIATION...Thomas
MARINE...Thomas