117
FXUS63 KGRR 071025
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
625 AM EDT Sun Jun 7 2026

.KEY MESSAGES...

- Next Chance For Thunderstorms Monday into Tuesday

- Hot and Midweek with Chances (30-50 percent) for Thunderstorms

&&

.DISCUSSION...
Issued at 209 AM EDT Sun Jun 7 2026

- Next Chance For Thunderstorms Monday into Tuesday

High pressure today will result in pleasant summer weather with
highs in the upper 70s to mid 80s. Winds will be light and
variable before becoming more easterly this afternoon.

Thunderstorm chances return Monday as the upper level low over
Oklahoma tracks northeast along the upper level ridge. Most of
Monday will likely be dry, but could see some pop up thunderstorms
develop during the afternoon before the better lift arrives
Monday night into Tuesday with the trough axis and positive
vorticity advection. With precipitable water values approaching 2
inches and slow storm motions localized heavy rain is possible. We
remain in WPC`s marginal risk for rainfall exceeding flash flood
guidance on Tuesday. Soundings also support that we could get some
stronger winds with any isolated or multicell clusters of
thunderstorms.

- Hot and Midweek with Chances (30-50 percent) for Thunderstorms

Dew points will be in the 60s and 70s through much of the upcoming
week creating a humid environment. Temperatures will be on the
rise each day as well with Wednesday and Thursday expected to be
the hottest days of the week. It is these days we`ll need to
monitor for heat indices approaching or exceeding 100. However
there will be chances for thunderstorms both of these days that
could impact temperatures and limit heat index values. Wednesday
chances are lower in the 20s and 30s and mainly focused in the
morning with lift at 850mb. Thursday chances are better (40 to 60
percent) during the late afternoon and evening. This could be
another period to watch for severe thunderstorms.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 625 AM EDT Sun Jun 7 2026

Some shallow patchy ground fog has developed this morning and
should quickly burn off. VFR conditions are expected into Monday
morning. A FEW diurnal cumulus deck around 3500 feet is possible
this afternoon. Light northeast winds slowly shift to the
southeast by Monday morning. A lake breeze may briefly bring a
period of north to northwest winds this afternoon along the
lakeshore.

&&

.MARINE...
Issued at 209 AM EDT Sun Jun 7 2026

Light east to northeast winds today become more north to
northwesterly along the lakeshore as the lake breeze develops this
afternoon. Easterly winds then return this evening and become
southeasterly for Monday. Thunderstorms will be possible late
Monday afternoon with better chances Monday night into Tuesday.
Additional chances for storms exist for Wednesday and Thursday.

Small Craft Advisory conditions may be possible in the southwest
winds expected Wednesday into Thursday and also may result in high
swim risk conditions for areas north of Grand Haven.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.

&&

$$

DISCUSSION...RAH
AVIATION...RAH
MARINE...RAH