461
FXUS63 KGRR 041746
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
146 PM EDT Sun Oct 4 2026
.KEY MESSAGES...
- Brief Period of Rain this Morning
- Areas of Frost Possible Tonight and Monday Night
&&
.DISCUSSION...
Issued at 222 AM EDT Sun Oct 4 2026
- Brief Period of Rain this Morning
A shortwave trough is moving through this morning with plenty of
positive vorticity advection and 700 mb frontogenesis. These
showers are elevated as seen in observations with cloud bases
around 8 to 10 kft. As radar trends continue it looks like most
will see light rain before the 850 mb front clears around 9am.
Dry conditions are expected through the remainder of the forecast,
but Tuesday night into Wednesday will need to be monitored. A
decent low level jet, warm air advection ahead of the shortwave
trough and front will be present. The question is will there be
enough moisture. Currently better chances are north of the area,
but the ENS members highlight light rain across the forecast area.
If this trend continues, chances for precipitation will need to be
added.
- Areas of Frost Possible Tonight and Monday Night
High pressure builds in tonight and continues into Monday. 925 mb
temperatures will fall into the 6 to 8 C range. The inversion that
develops isn`t overly strong so expecting inland areas along and
north of U-10 to have the best chance for lows dropping into the
mid 30s with isolated colder spots. However confidence is not high
at this time as there has been a slight warming trend in the data.
In coordination with Gaylord held off on issuing a Frost Advisory
at this time due to the uncertainty.
Monday night will have a better chance for more widespread frost
as low temperatures drop into the mid to upper 30s across areas
largely east of US-131 and north of I-96. The best chances (50
percent) for lows in the low to mid 30s will be inland areas along
and north of US-10.
&&
.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 146 PM EDT Sun Oct 4 2026
No major aviation concerns are expected over the course of the
next 24 hours, 18z to 18z. If there is one, it is the MVFR
ceilings that have pressed into the MKG area. Model guidance and
satellite loops support a thinning of these ceilings and likely a
rise as well given we are approaching the max in diurnal heating.
The bottom line is we feel these MVFR ceilings will lift and begin
to thin/scatter out over the course of the next 1-3 hours. We are
not expecting the MVFR conditions to make it into the other TAF
sites. There is a small potential for ceilings below 3k feet at
GRR, but not much more than an hour or so.
Otherwise we expect clearing to take place later this afternoon
and evening with little to no clouds expected for the remainder of
the TAF period. Fog should not be an issue tonight given winds
just off the deck in the 10-20 knot range.
West to northwest winds this afternoon that will gust into the
10-20 knot range will settle to light and variable tonight.
&&
.MARINE...
Issued at 222 AM EDT Sun Oct 4 2026
Winds will pick up from the southwest as this morning`s rain
clears and then shift to the west and northwest during the late
morning and afternoon. Waves build into the 4 to 7 foot range
north of Holland with the highest waves north of Muskegon. Gusts
around 20 to 25 knots may linger longer into tonight for areas
north of Grand Haven. Additionally waves may approach 4 feet near
and south of South Haven. Therefore the Small Craft Advisory will
likely need to be adjusted for this evening into Monday morning.
Another period of Small Craft Advisory conditions looks to develop
Tuesday with strong southwesterly winds. There is the potential
that a brief period of gales develops towards Little and Big Sable
Tuesday afternoon.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 8 AM EDT Monday for LMZ844>849.
&&
$$
DISCUSSION...RAH
AVIATION...Duke
MARINE...RAH
NWS GRR Office Area Forecast Discussion
