780
FXUS63 KGRR 261810
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
110 PM EST Wed Nov 26 2025

.KEY MESSAGES...

- Winter Storm with damaging winds possible today and tonight

- Lake Effect snow through Thursday

- More snow possible over the weekend.

&&

.DISCUSSION...
Issued at 330 AM EST Wed Nov 26 2025

- Winter Storm with damaging winds possible today and tonight

Bottom line upfront: Snowfall, heavy at times, is expected this
afternoon and evening. Expect winds to strengthen as the day
continues with strong possibly damaging winds this afternoon and
evening. This strong system will transition to primarily lake
effect snowfall Thanksgiving day with persistent snowfall, gusty
winds and blowing snow. Expect reduce visibilities today and
tomorrow with whiteout conditions that will make travel
treacherous.

Moist, southerly flow continues this morning with rain showers
streaming through southern lower Michigan as of 3 AM. Stable low
level clouds along with warm, moist air reside across the area
with dewpoint depressions around 1 to 2 degrees. That warm air
will be displaced around sunrise as a dry, cold front advects into
the region dropping 850mb temps by 10C by 12Z. Strong
frontogenesis will transition any lingering rain showers to snow
fairly quickly. The upper level low will track through northern
Lower Peninsula with a strengthening low level jet moving over
the area this afternoon. Winds aloft will shift from the southwest
to westerly as the short wave passes through. The core of the LLJ
will be moving through the I 94 corridor between 18Z and 00Z.
Coupled with lake moisture, a fairly deep Dendritic Growth zone
and good frontogenetic forcing, expect increased snowfall rates
to southwest Michigan. The heaviest snowfall through the southwest
should be between 21Z and 03Z with stronger snowfall rates along
the US 10 corridor tonight. Have adjusted snowfall amounts
somewhat based on the wet conditions.


- Lake Effect snow through Thursday

 The large upper level low will make its way across Lake Huron and
into southern Canada. The flow will shift from a westerly
direction to northwesterly flow. That convergent upper level flow,
strong mid level gradient and mid level moisture coupled with
-10C 850 mb air over +10C air over Lake Michigan is a good
 environment for lake effect snow. A secondary upper level trough
 on the back side of the exiting low will provide another layer of
 upper level forcing and dynamics to aid the mid level moisture
 and strengthen the pressure gradient across Lake Michigan. That
 persistent flow will keep snow bands moving across southern lower
 through at least the first half of Thursday. There is some
 question as to when the snow will taper off. As the flow shifts
 further to the NW there is strong indication that after 03Z
 Friday, the best mid level moisture will have moved off the lake
 and to the northeast along with a stark decrease in Omega through
 the mid levels. That will signal an end to heavier snow rates
 and ending of this event.

- More snow possible over the weekend.

Another winter system will be moving through the region this
weekend. An upper trough should be driving a surface low pressure
Across the plains Friday night and tracking through the Great
Lakes Saturday into Sunday. Temps through this system remain well
below freezing. Mid range models continue to show 3-6 inches of
snow is possible with locally higher amounts. Latest ensembles
showing this potential as well. That system should exit the region
late Sunday night.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 110 PM EST Wed Nov 26 2025

IFR will be driven by areas of Lake-Michigan-enhanced snow this
afternoon into tonight, while ceilings generally range from 1,000
to 2,500 feet. Strong wind gusts from the west are expected to
peak at 40 to 50 knots this evening. Blowing snow and bands of
lake effect snow continue into Thursday/Thanksgiving, with
variable visibility down to IFR.

&&

.MARINE...
Issued at 701 AM EST Wed Nov 26 2025

Gales this morning will increase to Storm force winds. Winds
upwards of 55 knots are expected this afternoon. The storm
warning will continue into tonight. Winds will slacken slightly
overnight into Thursday. Winds will shift to the northwest and
Gales are expected Thursday into Thursday night.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...High Wind Warning until 7 AM EST Thursday for MIZ037-043-050-056-
     064-071.
     Winter Storm Warning until 7 PM EST Thursday for MIZ037>039-
     043>045-064-065-071>073.
     Wind Advisory until 7 AM EST Thursday for MIZ038>040-044>046-051-
     052-057>059-065>067-072>074.
     Winter Weather Advisory until 7 PM EST Thursday for MIZ040-046-
     050-051-056>058-066-074.
MARINE...Storm Warning until 1 AM EST Thursday for LMZ844>849.

&&

$$

DISCUSSION...Ceru
AVIATION...CAS
MARINE...Ceru