793
FXUS63 KGRR 141854
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
254 PM EDT Sun Jun 14 2026
.KEY MESSAGES...
- Drying Out This Evening Through Monday
- Active Weather Returns Tuesday and Wednesday
- Windy Thursday
&&
.DISCUSSION...
Issued at 253 PM EDT Sun Jun 14 2026
- Drying Out This Evening Through Monday
The cold front has cleared western Lower MI today with the back edge
of rainfall moving across south central and SE portions of the
state. A stray shower may still be possible east of US 131 this
evening but the trend is for drier conditions. Not thinking we`ll
completely clear the skies for the remainder of the day given
upper troughing moving in through evening with cold air advection
in place (850mb temperatures dropping from +11C to +4C through
the day) and an abundance of upstream cloud cover across WI.
Partly to mostly cloudy skies this evening will clear out
tonight. Monday will feature low dew point readings in the 40s and
mostly sunny skies as model guidance supports low 70s for highs
during the afternoon.
- Active Weather Returns Tuesday and Wednesday
A negatively tilted upper trough arrives during peak heating on
Tuesday. Below this, a LLJ of around 40 kts develops and a surface
cold front is forecast to be situated near a Green Bay to Milwaukee
line around 18z Tuesday. Nam3km and RRFS guidance indicate somewhat
questionable instability during the day as dew point readings look
mediocre (55-60F). While the typically more moist and unstable
Nam3km shows MLCAPE values of 1000-2000 J/kg, the RRFS indicates
less than 1000 J/kg. Much of this will depend on whether morning
showers move into the lakeshore area and impact daytime heating. If
rain holds off until midday or later, there is a greater chance for
thunderstorms. Nam3km soundings indicate the most likely area for
deep layer shear to reach 30-40 knots is near and south of I-96,
where convection has the greatest potential to become organized. The
700-500 mb lapse rates look pretty good at about 7.5 C/km with some
CAPE present in the hail growth region, so some storms may contain
hail. Scattered thunderstorm wind gusts exceeding 40 mph will be
possible but severe gusts of 60 mph or greater would be isolated if
they do occur. Storms look to exit the bulk of the region in the 7pm-
9pm window Tuesday night.
A climatologically unusual synoptic pattern sets up later Wednesday
reminiscent of a cold season setup with a deep low moving through
the Great Lakes, indicated by ECMWF/GFS both showing MSLP values
approaching 5 standard deviations below normal for mid June, which
is extreme. This is not likely to be a severe weather event for
Michigan, however, as only elevated instability (and modest at that)
moves in Wednesday night with a brief window for weak surface
based instability during the overnight hours primarily south of
I-96. Might be a low risk for strong wind gust potential during
that time frame with any thunderstorms that manage to get rooted
closer to the surface. What is more likely is that a fairly
widespread rain moves in during Wednesday afternoon or evening and
into Wednesday night with some embedded thunderstorms after 00z.
ECE/GEFS/CMC ensembles all are showing 50th percentile 24 hr QPF
of 0.50"-1.00" by Thursday morning. Deterministic runs support
some swaths of over 1.00" of rain.
- Windy Thursday
Cold air advection on the back side of the departing low on
Thursday will usher in some windy conditions as ensemble and
deterministic guidance supports wind gusts of 30 to 40 mph during
the day.
&&
.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 132 PM EDT Sun Jun 14 2026
Rain will exit the area over the next few hours with KJXN likely
to see some showers linger the longest. Occasional MVFR ceilings
possible at least for a few hours at KJXN and maybe at KAZO and
KBTL as well. Otherwise...sky will trend toward clear this
evening with VFR conditions expected to persist through tomorrow.
&&
.MARINE...
Issued at 253 PM EDT Sun Jun 14 2026
SCA and Beach Hazards Statements will continue into this evening
with hazardous winds and waves along the shore from Ottawa County
south. Expect improving conditions tonight into Monday when we
should be free of marine headlines. Increasing SW flow ahead of a
cold front Tuesday will help generate hazardous waves once again.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement until 8 PM EDT this evening for MIZ056-
064-071.
MARINE...Small Craft Advisory until 8 PM EDT this evening for LMZ844>846.
&&
$$
DISCUSSION...Hoving
AVIATION...Maczko
MARINE...Hoving
NWS GRR Office Area Forecast Discussion
