772
FXUS63 KGRR 171923
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
323 PM EDT Wed Jun 17 2026
.KEY MESSAGES...
- Slight Risk of Storms and Potential Flooding This Evening
- Cooler Than Normal Temperatures Ahead
- Showers and Storms Possible Sunday into Monday
&&
.DISCUSSION...
Issued at 255 PM EDT Wed Jun 17 2026
- Slight Risk of Storms and Potential Flooding This Evening
There has been some minor changes to the threats this afternoon
and evening. While light rain has begun across the region, the
axis of heavy rain continues to shift due to the position and
track of the low. Latest CAMS are reflective of this.
Cooling behind showers that have recently moved through IL and
IN and through far SW Michigan has caused a "wake" low and thus
gusty winds over southern Lake Michigan. This can be see at the
buoys with wind gusts upwards of 57 kts in IL and 42 kts off the
coast of IN.
The precip shield and lingering showers have increased stability
so will weaken the strength of the winds ability to mix to the
surface and the amount they will be able to advect northward. In
areas where reflectivities drop then the winds will be able to
cycle to the surface and bring some increased wind velocities.
Showers and storms will continue to be on the increase as the
evening continues. There remains some question on track but latest
CAMS brings a few waves of storms through the area due to the low
passage this afternoon and evening. There remains some large shear
values moving in from the southwest. However, the best shear
doesn`t seem to be in sync with the best instability. So while
there is some weak rotation possible, the best tornado threat
remains out of the area though given the shear and winds, a brief
gustnado is possible. The main threat will be damaging winds as
storms move through between 4 pm to 11 pm. The upper level wave
will shift to the east and any lingering precip will fade after
06Z.
- Cooler Than Normal Temperatures Ahead
The large upper level low over Canada will keep cooler air
advection into the area through the latter half of the week and
keep temperatures lower through that timeframe. Expect highs to
struggle to get out of the mid 70s which is 5 to 10 degrees cooler
for this time of year.
- Showers and Storms Possible Sunday into Monday
The next shortwave trough ejecting from the western CONUS may
develop another surface low over the Plains to Midwest late in the
weekend. Depending on the track, another batch of heavy rain
could move in later on Sunday. There is some question on the track
and timing as is shown through the ensembles. There is the
potential it tracks further south and misses MI completely.
&&
.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 138 PM EDT Wed Jun 17 2026
Prior to the development of thunderstorms this afternoon, we`re
watching for the potential for wake low induced strong surface
winds to potentially develop. Winds have gusted to 48kts at MDW
and 55 kts over the lake. Not confident enough to put in the TAFs
yet, but we`re aware of what`s occurring west of here.
A deep low pressure system moving into the region will help to
generate strong to severe storms this afternoon. Strong winds are
the main threat. Additionally, once the precipitation diminishes
this evening, IFR cigs are expected to develop.
&&
.MARINE...
Issued at 255 PM EDT Wed Jun 17 2026
Several Marine issues today. A wake low moving behind showers
this afternoon could bring gale level winds. Several rounds of
storms this evening are expected which could prompt special
Marine warnings. Winds out of the southwest will shift due west
this evening and then to the northwest overnight through the first
half of tomorrow. Those winds and waves will allow for SCY
conditions along with beach hazards through the first half of
tomorrow before subsiding.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement from 2 AM EDT Thursday through Thursday
afternoon for MIZ050-056-064-071.
Flood Watch until 2 AM EDT Thursday for MIZ064>067-071>074.
MARINE...Small Craft Advisory until 4 PM EDT Thursday for LMZ844>849.
&&
$$
DISCUSSION...Ceru
AVIATION...04
MARINE...Ceru
NWS GRR Office Area Forecast Discussion
