326
FXUS63 KGRR 112357
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
657 PM EST Wed Nov 11 2026
.KEY MESSAGES...
- Light rain possible today
- Cooler Thursday, lake shore rain/snow showers through Saturday
&&
.DISCUSSION...
Issued at 206 PM EST Wed Nov 11 2026
- Light rain possible today/tonight
Water vapor imagery shows a short wave in western IL being nudged
eastward by another short wave dropping south across northwest IA within
a deepening upper trough. The IL short wave is producing light
rain across the northern half of the cwa, with much more sparsely
populated echos south of I-96. A wider radar view shows more
showers/storms moving across northern IL. Model trends point
toward the IL thunder remaining south of the cwa. All of the
precipitation tonight will be light rain.
- Cooler Thursday, lake shore rain/snow showers through Saturday
The IA short wave will drag down colder air tomorrow as it pivots
through the upper trough. H8 temperatures near +2c today will fall
to -7c Thursday. The north flow that will be generated by the
short wave will coupled with the cold advection will produce lake
effect rain showers mostly over the lake, but clipping the lake
shore too. While boundary layer air will be too warm for snow
Thursday, that could change Thursday night as the temperature
drops. If any snow does develop Thursday night, the lake shore
north of Whitehall has the highest chance of seeing it. That area
could potentially see a few tenths of an inch of snow. The bulk of
the precipitation will be just west of the lake shore falling over
the lake.
The upper trough will remain over the state through Saturday
before beginning to lift northeastward. The colder air will remain
too with h8 temps in the -6c to -8c range through the weekend.
That will produce surface temperatures in the mid 40s for highs
through Monday before the trough moves east and then ridging noses
into the region. At that point highs will climb into the 50s
early/mid week.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 657 PM EST Wed Nov 11 2026
Main change was to add detail to expected fuel alternate ceilings
after 06Z. We carried VCSH rather extensively with episodic light
rain being possible early tonight. Nonetheless, we estimate a 90
percent chance of VFR conditions prevailing at the terminals
through 06Z.
Water vapor imagery shows a well defined vort max moving east
across extreme southern Lake MI at this time. Broad mid-level
deformation associated with this extends roughly from the Holland
area to the Michigan thumb. Surface reports of light rain appear
to be confined to along and east of US-127 associated with that
broader deformation zone, however.
Over far southwest Lower MI, we are seeing respectable reflectivity
aloft immediately downstream of the vort max, but no surface
observations of rain. This may speak to a very dry sub-cloud
layer in that vicinity, possibly being reinforced by northeasterly
flow near the surface. Moistening is expected to occur overnight
though, resulting in a gradual lowering of ceilings across the
region overnight.
Some observation sites over far southwest Lower MI, including
AZO/BTL, are rather gusty at the present time, but expect this to
be short lived as the upper vort max passes east of the area.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 7 PM EST Friday for LMZ844>849.
&&
$$
DISCUSSION...04
AVIATION...TJT
NWS GRR Office Area Forecast Discussion
