473
FXUS63 KGRR 281837
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
237 PM EDT Tue Jul 28 2026

.KEY MESSAGES...

- Dry through Thursday night

- Rain returns to the forecast for Friday through Saturday night

- Temperatures near to slightly above normal through forecast

&&

.DISCUSSION...
Issued at 236 PM EDT Tue Jul 28 2026

- Dry through Thursday night

Surface high pressure will build into the region from the north
tonight. The center of the high at the present time (18z) is over
Western Lake Superior. The high slowly moves south through
Wednesday night and will be centered over Lower Michigan Thursday
morning. The high then moves away to the southeast Thursday
night. Subsidence and a lack of deep moisture will allow us to
keep a dry forecast through Thursday night. Night time lows will
be in the 50s to lower 60s with day time highs in the low 80s.
Very pleasant weather for mid summer.

- Rain returns to the forecast for Friday through Saturday night

The high sliding away will allow moisture return to occur on the
back side. BUFKIT overviews of moisture in the vertical are fairly
stark with little to no moisture in place through Thursday night.
On Friday deep moisture surges back in through the depth of the
atmosphere. The deep moisture will be in place from Friday evening
through Saturday evening. Our highest chances for precipitation
will be during this time frame (50-60 pct), but could see this
needing to be nudged up with time.

A healthy mid level shortwave trough will swing through the region
moving directly overhead Friday night and Saturday. The surface
reflection will be well south of our area with the low passing
from Illinois into the Ohio Valley. If the low was in closer
proximity we would have higher chances for rain. Given the south
track of the low, moisture at the surface is not exceptional by
mid summer standards. Low to mid 60s dew points are all we look
to muster which results in limited MUCAPE/instability. MUCAPE
values for the most part remain below 700 j/kg through the time
the trough is swinging through. There appears to be a brief window
Sunday morning where low level moisture lingers in the south
where we may crest 1,000 j/kg. Bottom line the pattern looks
conducive for occasional showers with a few embedded
thunderstorms. Not expecting severe weather at this time. Dry
weather returns for Sunday evening into early next week.

- Temperatures near to slightly above normal through forecast

Temperatures through the period look to be seasonal for the most
part with highs in the 80s almost every day and lows for the most
part in the 60s. We will see some 50s as well for lows. Normal
highs are low 80s and normal lows are around 60. 850mb
temperatures in the middle teens C lend credence to the forecast
temperatures.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 128 PM EDT Tue Jul 28 2026

MVFR cigs will break up over the next 1-2 hours with conditions
becoming VFR through the rest of the TAF period. Most guidance is
to optimistic with cig breakup so leaned on LAMP MOS and satellite
for timing out improvement. Wind gusts of 15-25 knots expected
through the afternoon before winds subside this evening.

&&

.MARINE...
Issued at 236 PM EDT Tue Jul 28 2026

Waves are in the 3 to 5 foot range at the buoys as of 1-2pm. Winds
are just now beginning to crest the 20 knot threshold at a few
lakeshore ob sites so we expect the wave field to increase as
well. Will stick with the going forecast of waves peaking early
this evening in the 4 to 7 foot range. Highest waves will be found
this evening south of Grand Haven and especially Holland. Will
maintain the Small Craft Advisory and the Beach Hazards Statement
through 200am. The far southern zone, south of South Haven, may
see waves hang on a bit longer than 200am, but not by much more
than an hour or so.

A very brief advancing high event is possible Wednesday afternoon
where waves may build to around 3 feet in the late afternoon and
early evening. We will keep an eye on this potential wave event.
High pressure will bring a period of lower winds and waves from
Wednesday evening lasting into Friday morning.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement through late tonight for MIZ037-043-050-
     056-064-071.
MARINE...Small Craft Advisory until 2 AM EDT Wednesday for LMZ844>849.

&&

$$

DISCUSSION...Duke
AVIATION...Thomas
MARINE...Duke