Jenison, Michigan Weather Forecast Discussion

533
FXUS63 KGRR 271924
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
324 PM EDT Sat Sep 27 2025
.KEY MESSAGES...
- Dry forecast the next 7 days
- Above normal temperatures expected
&&
.DISCUSSION...
Issued at 324 PM EDT Sat Sep 27 2025
- Dry forecast the next 7 days
We have a dry forecast for the next 7 days. No matter the variable
looked at for the potential for precipitation the message is all
the same...dry. GFS BUFKIT overviews show very little moisture
below 15,000 feet all the way through next Saturday. Suffice it to
say, is very hard to get precipitation with dry air in the lowest
15,000 feet of the atmosphere. Extended MOS guidance from both the
12z GFS (MEXGRR) and 12z ECMWF (ECXGRR) both show 24 hour chances
for precipitation below 5 percent through Wednesday.
The reason for the dry weather is a stagnant pattern which
features ridging both at the surface and aloft. The upper ridging
peaks aloft from tomorrow (Sunday) through Tuesday. 500mb heights
around 590dm during that time frame are mid summer values. 500mb
heights are 2 standard deviations above normal. The reason for our
high 500mb heights, which will bring warm and dry weather, is due
at least in part to the tropical systems off the southeast U.S.
coast early this week. As is typical in these scenario`s the
tropical system(s) likely soon to be plural (2), Humberto and
Imelda, block the pattern up and we remain beneath ridging in the
Great Lakes. Bottom line high confidence in dry weather the
remainder of the weekend and for the upcoming work week as well.
- Above normal temperatures expected
Normal high temperatures across the region today range from 66 at
Houghton Lake near the far north edge of our forecast area to 70
at Kalamazoo. Forecast highs the next 7 days will likely be middle
70s to lower 80s each day. Given we are approaching October we
would classify this weather as warm. Record lows this time of year
are in the 20s and we won`t be anywhere close to those values.
&&
.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 120 PM EDT Sat Sep 27 2025
VFR conditions are likely over the next 24 hours with one main
caveat. There is a low (10-20 percent) chance of MVFR and lower
conditions at MKG due to fog given elevated crossover
temperatures. There are mitigating factors however including a
more turbulent boundary layer due to an approaching cold front.
This cold front will cross the area overnight causing our
predominantly west southwest flow to become northwesterly into
the day on Sunday. Skies will be clear to mostly clear through the
TAF period.
&&
.MARINE...
Issued at 324 PM EDT Sat Sep 27 2025
Conditions are expected to remain below Small Craft Advisory/Beach
Hazards Statement levels the next several days. Southwest winds
around 10 knots are expected through the end of the day. Tonight
will feature a brief increase of winds from the north to around 15
knots near Big and Little Sable Points as a cold front crosses
the waters. Our next chance for more substantial winds across the
waters is Wednesday as a strong high moves through eastern Canada
interacting with a low out west. Given the dominance of the high
offshore flow with this event is favored at this time. Dry weather
is expected to continue into early next week.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.
&&
$$
DISCUSSION...Duke
AVIATION...Thomas
MARINE...Thomas

NWS GRR Office Area Forecast Discussion