272
FXUS63 KGRR 010158
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
958 PM EDT Sat May 31 2025

.KEY MESSAGES...

- Frost Potential Tonight

- Quick Warm up with Heavy Rain Potential Next Week

&&

.DISCUSSION...
Issued at 325 PM EDT Sat May 31 2025

- Frost Potential Tonight

A Frost Advisory has been issued for the northern two rows of
counties for tonight, and patchy frost is possible in the colder
spots throughout the forecast area.

Northerly flow continues advect in lower dew points this
afternoon and the dry, cool airmass will be accompanied by light
winds and clear skies tonight, except for some elevated smoke
which should not affect radiational cooling conditions. With
forecast dew points in the upper 20s to lower 30s, some rural
areas will drop into the lower 30s, with mid to upper 30s
widespread across much of the forecast area.

- Quick Warm up with Heavy Rain Potential Next Week

The narrow upper trough and sfc high move east on Sunday with warm
advection beginning Sunday night. Moisture is limited though and
no measurable precip is expected although sprinkles can`t be ruled
out as warm advection mid clouds increase early Monday morning.

Then upper ridging builds in for later Monday into Tuesday along
with deep moisture pooling ahead of an advancing western CONUS
trough and sfc cold front. The heavy rain potential for Tuesday
night into Wednesday continues to be watched. Organized convection,
with 35 to 40 knots of deep layer shear, looks to move in Tuesday
evening and only slowly advances east as a blocking upper high
forms and persists across the SE CONUS. The potential for training
of heavy rain could continue through Wednesday and into Wednesday
night as the front slows down and upper flow becomes parallel to
it. Some areas could see storm total rainfall over 2 inches by
Wednesday night.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 717 PM EDT Sat May 31 2025

VFR is expected over the next 24 hours with plenty of dry air
below 20,000 feet. Northwest winds will relax closer to 5 knots as
the sun sets this evening. Ceilings 16,000 becoming 10,000 feet
are primarily due to a noticeable smoke layer, heights estimated
based on the experimental HRRR-Smoke model. There may also be
some cirrus clouds above this smoke layer later tonight into
Sunday.

&&

.MARINE...
Issued at 955 PM EDT Sat May 31 2025

Winds and waves have fallen below Small Craft Advisory and Beach
Hazards Statement criteria and therefore both have been cancelled.
Winds and waves will remain at sub advisory levels at least into
Sunday evening.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Frost Advisory from 1 AM to 8 AM EDT Sunday for MIZ037>040-
     043>046.
MARINE...None.

&&

$$

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