Weidman, Michigan Weather Forecast Discussion

016
FXUS63 KGRR 051942
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
342 PM EDT Sun Oct 5 2025
.KEY MESSAGES...
- Chances for showers and storms Monday through Tuesday
- Cooler and mainly dry the remainder of the 7 day forecast
&&
.DISCUSSION...
Issued at 340 PM EDT Sun Oct 5 2025
- Chances for showers and storms Monday through Tuesday
Another warm day today with temperatures well above normal in the
lower to middle 80s across the area. We are in deep southwest flow
into Monday with one last warm day in the forecast. Forecast highs
on Monday remain in the lower to middle 80s across much of the
area, the exception being the far northwest towards Ludington
which will be in the clouds and advancing precipitation zone
tomorrow.
The main forecast focus is centered on really the only
precipitation chances in the 7 day which occurs from Monday into
Tuesday. At 19z, the front stretches north to south across
Minnesota, into NW Iowa and into Kansas. This front will make
steady progress in our direction tonight driven by an upper
shortwave trough moving across southern Canada. By daybreak on
Monday the front will be poised just upstream over Wisconsin
stretching from near Green Bay to southeast Iowa. The front will
move into our northwest forecast area near Ludington Monday
afternoon and slow Monday night across the area as the front
becomes more parallel to the upper flow. It will gradually push
out of the area to the south on Tuesday. Scattered pops of 20-50
percent seem warranted on Monday, increasing to 60-90 percent
Monday night as the front slows to 20-40 percent on Tuesday.
Embedded thunderstorms are expected especially Monday afternoon
into Monday evening as a diurnal boost occurs. Instability
parameters are nothing significant, but enough for a few
storms...500-1000 MUCAPE and 850 LI`s of zero to -2C. PWAT`s near
1.5 inches are high for this time of year. 850mb dew points
increase to +10C. The surge in moisture combined with a slowing
front may lead to some locally heavier amounts of rain. A few
swaths of 0.50 to 1.00 are certainly possible. The HREF would even
suggest very small areas of 1.5 inches by 12Z on Tuesday. Not
expecting any hydro issues though given dry soil moisture, low
river levels and rainfall amounts that are not overly high. Threat
for severe weather is low as well given the better shear lags the
front and instability is on the low side. SPC general thunder
outlook is in line with our thoughts.
- Cooler and mainly dry the remainder of the 7 day forecast
Beyond the exiting front and diminishing precipitation on Tuesday
there is no significant weather to speak of. Surface high pressure
builds in and really remains in the area from Wednesday into next
weekend. A taste of true fall shows up behind the cold front as
low temperatures dip into the 30s Tuesday night and Wednesday
night. We could see frost/freeze headlines mid week. The ECWMF
actually has 850mb temperatures dipping to zero C on Wednesday.
Highs mid week will be much closer to normal in the 60s.
&&
.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 144 PM EDT Sun Oct 5 2025
As has been the case for most of the last couple of weeks, VFR
conditions will rule for the next 24 hours.
At the beginning of this forecast period, we have some cumulus
clouds based around 6k ft agl developing inland, with a few wisps
of cirrus overhead. This will continue to be the case through
sunset. Some wind gusts to around 25 knots will also be present
this afternoon before diminishing.
Skies will go mostly clear after sunset with winds diminishing as
the atmosphere decouples. We are looking at a 30-35 knot wind core
moving in around 2-3k ft toward midnight. This is not usually
quite enough to mention low level wind shear in the forecast, but
it is good to mention here. KMKG will likely see the winds pick up
as this wind core arrives near the warmer lake.
Winds will pick up at the sfc by 16z or so as diurnal mixing takes
place. Clouds will increase at the NW sites as the cold front will
approach there late in this forecast period, and just after it.
Have mentioned BKN070 at KMKG and KGRR to account for that.
&&
.MARINE...
Issued at 340 PM EDT Sun Oct 5 2025
No changes are needed to the current set of marine headlines that
are in effect from South Haven northward. The worst of the
conditions this afternoon are north of Grand Haven in the flow from
the SSW. The flow will gradually shift to more from the pure SW, and
bring the higher waves further south on Monday. The current
expiration time of 16z looks good as the gradient will weaken by
Monday afternoon, and the waves will subside correspondingly.
We could see some elevated wind and waves remain on Tuesday behind
the front and as the next sfc ridge builds in. Right now, the
magnitude of that event would likely just fall short of needing
headlines. We will continue to monitor that event.
After Tuesday, we will likely go the rest of the week without any
potential headlines as we get into another quiet weather pattern.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement through Monday afternoon for MIZ037-043-
     050-056-064.
MARINE...Small Craft Advisory until 5 PM EDT Monday for LMZ845>849.
&&
$$
DISCUSSION...Duke
AVIATION...NJJ
MARINE...NJJ

NWS GRR Office Area Forecast Discussion