Portage, Michigan 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

848
FXUS63 KGRR 242257
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
657 PM EDT Fri Jul 24 2026

.KEY MESSAGES...

- Thunderstorms Possible Late Saturday into Monday. Severe storms
  possible, but confidence in where/when/if storms impact West
  Michigan is low at this time.

- Northwest Flow Continues Into Late Next Week

&&

.DISCUSSION...
Issued at 212 PM EDT Fri Jul 24 2026

- Thunderstorms Possible Late Saturday into Monday. Severe storms
  possible, but confidence in where/when/if storms impact West
  Michigan is low at this time.

Surface ridging and poor moisture quality keeps conditions dry over
the next day or two, with precipitation chances holding off until
Saturday Night. Saturday night a weak shortwave crosses the area.
However, poor moisture quality keeps precipitation chances low (20-
25%) across the area with most seeing a few hundredths of an inch of
rain or less.

Attention then turns to the Sunday/Monday timeframe where we
transition into a Ring of Fire setup on the eastern periphery of an
upper-level ridge. Long range CAMs and other NWP guidance suggest
that one or more clusters form on this ridge and track through Great
Lakes region. Sunday Evening/Night and Monday Evening/Night are the
favored windows at this time. However, these setups are well known
for being very difficult to nail down the timing and placement of
any thunderstorms. Some solutions suggest development near peak
heating Sunday as well, and some suggest the storms miss the region
all together. This whole timeframe has at least some potential for
thunderstorms.

Forecast soundings show a conditional severe weather threat in this
timeframe , meaning that if the storms track through West Michigan,
the environment will be favorable for severe weather. Sunday will
feature MUCAPE values near or above 2000 J/kg with 40+ knots of deep
layer shear, definitely sufficient for severe thunderstorms. The
same environment may exist into Monday/Monday Night as well, with a
more favorable mid-level jet placement across the area.

Bottom line is environment is favorable for one or more rounds of
severe thunderstorms early next week. However, confidence in where
and when those storms would occur (including whether they affect
West Michigan) is low given the synoptic pattern and dependence on
boundaries from previous convection. Will continue to monitor and
refine the forecast in the coming days.

- Northwest Flow Continues Into Late Next Week

Post the cold front later Monday into early Tuesday the northwest
flow pattern continues. Surface ridging returns and low-level
moisture diminishes for the mid-week period. This keeps conditons
dry until Friday when a shortwave may trigger showers.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 644 PM EDT Fri Jul 24 2026

VFR conditions will continue to dominate through the forecast
period. Winds are expected to go light/variable between 00Z to
01Z this evening. Winds will mix out of the southwest between 13Z
to 17Z. That mixing will increase with wind gusts upwards of 20kts
likely at MKG and GRR at 18Z and 20Z respectively. Winds will
remain gusty at times into the early evening.

&&

.MARINE...
Issued at 212 PM EDT Fri Jul 24 2026

Conditons remain below hazardous levels until Saturday afternoon.
Strengthening southwest flow of 15-18 knots may result in a marginal
High Swim Risk/Beach Hazards event north of Pentwater. Right now
moderate swim risk is favored but slightly stronger winds/more
onshore flow may nudge that to high. Dangerous winds and waves are
also possible Tuesday in northwest winds behind a cold front. One or
more rounds of thunderstorms are possible between Sunday and Monday
night. Confidence in if/when storms impact the waters is low,
however any storms may be capable of gusts over 34 knots.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.

&&

$$

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