533
FXUS63 KGRR 052308
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
708 PM EDT Mon Oct 5 2026
.KEY MESSAGES...
- Some frost across interior portions of Central Lower tonight
- Small Chances of rain North early Tuesday and Tuesday night
- Mostly dry and increasingly warmer Wednesday and beyond
&&
.DISCUSSION...
Issued at 232 PM EDT Mon Oct 5 2026
- Some frost across interior portions of Central Lower tonight
We have one more night in this series of cool nights where frost is
likely, mainly for the far NE portion of the area. This is the area
where winds will remain lighter closer to the sfc ridge, and a lack
of cloud cover will be late tonight. This does not look to be a
major event as temps have warmed up a little as compared to last
night.
- Small Chances of rain North early Tuesday and Tuesday night
The northern counties that do not look to have the frost potential
will see a bit more cloud cover overnight, and winds aloft
increasing as mentioned above. These factors will be the result of a
warm front that will be approaching that part of the area late
tonight and first thing Tuesday morning. These are likely to be
sprinkles more than anything else as the air below about 7-8k ft
will be rather dry.
After a dry day on Tuesday, there will be another small chance of
rain showers across the northern third of the forecast area. This is
the result of the cold front moving through and the associated upper
wave barely grazing the area. The upper jet core stays just north of
the area, and therefore the best forcing and instability will stay
north.
- Mostly dry and increasingly warmer Wednesday and beyond
The upper wave on Wednesday moves by, but the lower heights remain
entrenched across Lower Michigan and the region for one more day,
before the long wave trough exits the region. This will bring cooler
temperatures for the area after a brief warm up Tuesday and
Wednesday.
Upper heights will be rising then beginning Thursday night and will
continue into early next week as a long wave upper ridge slowly
builds our way. The building heights, and increasing return flow
from the SSW bringing a warm front through Friday night will give
the temperatures a nice bump for next weekend.
The aforementioned warm front coming through Friday night could
bring a small chance of brief light rain. Chances are that moisture
will be lacking in the lower to mid levels of the atmosphere. 850 mb
temperatures will be warming into the upper teens C, potentially
allowing some areas to approach 80 F this weekend.
There is some uncertainty next Monday, regarding an upper trough
that may try to come north out of the Western Gulf. Right now the
NBM blend is keeping the forecast dry. This could change depending
on how the long wave trough starts to move east and lifts it out.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 706 PM EDT Mon Oct 5 2026
Skies are clear across the terminals and winds will become light
within the next hour or so. IR loop shows some mid clouds moving
east across Wisconsin and they will move over the I-96 terminals
around 12z. Elsewhere, skies will be mostly clear.
&&
.MARINE...
Issued at 232 PM EDT Mon Oct 5 2026
We will be issuing a Gale Warning for the northern two marine zones
(north of Whitehall) for tomorrow and tomorrow evening. We will be
issuing a Small Craft Advisory for the northern two zones ahead of
the Gales for tonight and Tuesday morning, and Whitehall to South
Haven for Tuesday into Wednesday.
Stronger SSW winds ahead of a frontal system will arrive over the
nearshore waters late tonight, and last into Tuesday. The winds will
change to become from the WNW behind the system on Wednesday. It
looks to take until Wednesday afternoon for winds and waves to come
down below criteria.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Frost Advisory from midnight tonight to 8 AM EDT Tuesday for
MIZ039-040-045-046-052.
MARINE...Small Craft Advisory from 8 AM Tuesday to 4 PM EDT Wednesday for
LMZ845>847.
Small Craft Advisory from 5 AM to 2 PM EDT Tuesday for LMZ848-
849.
Gale Warning from 2 PM to 11 PM EDT Tuesday for LMZ848-849.
&&
$$
DISCUSSION...NJJ
AVIATION...04
MARINE...NJJ
NWS GRR Office Area Forecast Discussion
