394
FXUS63 KGRR 191818
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
218 PM EDT Fri Jun 19 2026
.KEY MESSAGES...
- Light Rain Saturday morning; Cooler temps continue
- Heavy rain Possible Late Sunday into Monday
&&
.DISCUSSION...
Issued at 215 PM EDT Fri Jun 19 2026
- Light Rain Saturday morning; Cooler temps continue
Downsloping, northwesterly flow continues to dominate the pattern
today with fair weather CU across lower Michigan. Breezy
northwesterly winds will filter through the weak ridge that is over
the region. That ridge will be short lived as a shallow short wave
propagates through the Great Lakes tonight through tomorrow
morning. Enough mid level moisture is present to create some
scattered showers tonight into early tomorrow morning. Best QPF
will be north of I 96, mainly along the lakeshore from Muskegon
northward. Latest model have around an inch of PWAT. The 75th
percentile of the ensembles is showing around a quarter inch of
precipitation possible by 12Z Saturday. 90th percentile is
slightly more. There is also a chance the best moisture remains
north and we only get light amounts. Given that variability, while
a brief downpour will be possible tonight into early tomorrow
morning, a tenth of an inc h of QPF overall is more than likely.
Any rainshowers will move quickly eastward tomorrow morning. The
persistent northwesterly flow will keep temperatures 5 to 10 degrees
below normal for the foreseeable future. So Max temps through
next week are expect to remain in the 70s.
- Heavy rain Possible Late Sunday into Monday
The next chance for rainfall will be Sunday night into Monday.
Models remain consistent that a low pressure system, supported by an
upper level short wave, will track across the Midwest. Latest
ensembles and the EC move the lows track slightly northward. That
would increase QPF throughout the region, with the I 96 corridor
receiving 0.75 to an inch of QPF and the the I 94 corridor
receiving an inch to an inch and a half. Latest NBM is trending
this way given the position of the low and the fact that the NAEFS
and EC ensembles shows Anomalous moisture through this timeframe.
Soundings through this timeframe are stable with a lack of shear.
So while a rumble of thunder is possible, it`s not expected. WPC
does have the area along and south of I 94 in a slight risk for
excessive rainfall due to heavy rainfall potential.
The low will move eastward Monday. After a few days of clearing
skies, The large upper level low that has been driving the pattern
should drop southward mid to late week. Timing varies but
precipitation will be possible late Wednesday through Thursday.
&&
.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 114 PM EDT Fri Jun 19 2026
SCT to BKN diurnal Cu are expected to continue through this
evening around 5kft inland of the lake shadow (meaning cloud
cover will be little at MKG through the afternoon). Tonight,
widespread clouds move in ahead of a cold front along with
scattered showers that have a low chance of affecting the
terminals, with a PROB30 at GRR/MKG where the chance is best. MVFR
cigs have a moderate (50-60%) chance of development based on
RRFS/other model soundings, highest at GRR. Any low ceilings
should dissipate by mid morning given strong June sunshine. Gusts
to around 20 knots expected through the afternoon before
diminishing this evening.
&&
.MARINE...
Issued at 213 PM EDT Fri Jun 19 2026
While there is gusty northwesterly flow, it`s light enough for
only 1 to 3 foot waves today and tomorrow. Not expecting any
headlines through Sunday. Next chance could be Monday in the wake
of the exiting system.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.
&&
$$
DISCUSSION...Ceru
AVIATION...Thomas
MARINE...Ceru
NWS GRR Office Area Forecast Discussion
