Sand Lake, Michigan Weather Forecast Discussion

139
FXUS63 KGRR 091751
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
151 PM EDT Tue Sep 9 2025
.KEY MESSAGES...
- Dry and mild through Friday
- Rain chances arrive Saturday
&&
.DISCUSSION...
Issued at 320 AM EDT Mon Sep 8 2025
- Dry and mild through Friday
No changes needed to the forecast through Friday. The front to our
west and northwest is still expected to weaken significantly before
it pushes through our area as mainly a windshift line on Wednesday.
This weakening is the result of the upper wave supporting the front
dampening out as the long wave ridge to our west becomes the
dominant feature over the region. Increasing subsidence and a lack
of moisture advection into the area will only dry the atmosphere out
more than it is already.
Temperatures continue to look like they will stay stable, and not
really cool off behind the front. 850 mb temperatures ahead of the
front will be 10-11C, while they will stay around 11C behind the
front. The only noticeable change will be the drier wind coming in
from the ENE.
- Rain chances arrive Saturday
Model ensemble means are starting to fine tune the details for the
rain chances coming this weekend. The main issue to resolve was the
interaction of the upper ridge building ENE from the SW, while
northern stream energy is forecast to dive SE toward the region also.
The latest ensemble means show that the northern stream low will not
be nearly as amplified as the Euro and its ensemble members had been
showing. This now looks like it may stay just NE of the region. This
scenario then looks to allow the upper ridge to build a bit more
toward us, and for our area to see some showers and storms at the
nose of a low level jet associated with a southern stream wave
riding over the upper ridge on Saturday.
Now, with the upper trough largely staying to our NE with the
northern stream weaker, we may end up under increasing subsidence
again with the upper ridge building in for Sunday. The Euro ensemble
mean has gravitated toward the ensemble means of the GEFS and GEPS.
This could bring the area back to warmer temps and dry conditions by
Sunday, and hold through Monday.
&&
.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 145 PM EDT Tue Sep 9 2025
Predominately VFR conditions will persist over West MI today,
tonight, and into Wednesday. Generally light southerly breezes
will continue through the TAF period, perhaps becoming light and
variable tonight.
Patchy upper clouds this afternoon will thicken and lower from
west to east (to some degree) tonight and Wednesday - thanks to a
weak and slow moving upper wave over the western Great Lakes.
Patchy late night MVFR/IFR fog can`t be ruled out at JXN and
perhaps LAN, consistent with this morning.
&&
.MARINE...
Issued at 320 AM EDT Mon Sep 8 2025
No changes are needed with the marine/beach headlines at this time.
The flow from the SW increases a bit with the approach of the
weakening cold front, especially the further north you go. The
highest waves will be found at Little and Big Sable Points today.
Once the imminent event diminishes tonight, we are looking at a few
days of quiet weather. High pressure will be over the area, and a
flow offshore will keep conditions fairly tame through Friday.
Saturday is looking like the next best chance of some rainfall.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement until 6 PM EDT this evening for MIZ037-
     043.
MARINE...Small Craft Advisory until 6 PM EDT this evening for LMZ848-849.
&&
$$
DISCUSSION...NJJ
AVIATION...Smith
MARINE...NJJ

NWS GRR Office Area Forecast Discussion