541
FXUS63 KGRR 060525
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
125 AM EDT Fri Jun 6 2025

.KEY MESSAGES...

- Near Normal Temperatures with Some Late Weekend Rain Chances

- Warming Up Later Next Week

&&

.DISCUSSION...
Issued at 336 PM EDT Thu Jun 5 2025

- Near Normal Temperatures with Some Late Weekend Rain Chances

Temperatures near normal with highs in the mid 70s and lows in the
mid 50s (cooler near Lake Michigan) should persist until mid next
week. High pressure will generally be in place over the region
through Saturday. On Friday, lingering moisture / higher humidity
over southern Michigan, and proximity to the stationary front and
weak low draped across Indiana/Ohio, may allow a few light rain
showers to develop near I-94.

There are a couple chances for showers and possibly a thunderstorm
between Saturday night and Sunday night. A weak shortwave trough and
associated surface low moving through the southern Great Lakes
Saturday night to Sunday morning may touch off showers depending on
its exact track, with chances for precip about 30 percent in
southern Michigan. On its heels is a larger and robust upper-level
low diving in from south-central Canada with a leading cold front
arriving later Sunday. Precipitation chances are greater than 60
percent near I-96 and to the north. CAPE progged around 500 J/kg is
worth a mention of a chance of a thunderstorm Sunday evening. There
will be some wind shear present also, supporting a threat of some
gustier winds.

- Warming Up Later Next Week

Ensembles are broadly in agreement of a warming trend next week
Wednesday into Friday with southwesterly low-level flow from the
south-central Plains toward the Great Lakes. Temperatures are
looking to climb into the 80s possibly Wednesday and likely Thursday-
Friday. With many ensemble members showing increasing PWAT, surface
dew points, and CAPE late in the week going into the weekend, both
heat/humidity and chances for thunderstorms will become more of the
story.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 124 AM EDT Fri Jun 6 2025

VFR conditions will prevail through Friday evening at most sites
except JXN where some IFR/MVFR is expected at times through the
afternoon as low clouds and fog persist. Winds will be light and
variable overnight then go northerly AOB 10 knots this afternoon.

&&

.MARINE...
Issued at 124 AM EDT Fri Jun 6 2025

Winds and waves expected to be relatively calm until late in the
weekend when south winds increase ahead of low pressure moving in
from the west. At this point it looks like winds and waves remain
below SCA criteria into early next week.

&&

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

&&

$$

DISCUSSION...CAS
AVIATION...Ostuno
MARINE...Ostuno