textproduct: Grand Rapids

KEY MESSAGES

- Quick Round of Snow, Freezing Drizzle Possible This Morning

- Another Round of Snow and Rain Tonight into Wednesday

- Reinforcing short of Arctic Air and Snow Showers Fri-Sun

DISCUSSION

Issued at 338 AM EST Tue Dec 9 2025

- Quick Round of Snow, Freezing Drizzle Possible This Morning

A quick round of snow will move through this morning bringing around an inch of snow for most of the area with 2 to 5 inches north of Grand Haven with the highest amounts north of Muskegon. As snow tapers off freezing drizzle/light rain could develop between 8am- 1pm. This is due to moisture profile flirting with -8C temperatures. One factor that could help is dry air toward the surface with breezy winds. Soundings are not persistent in keeping the low levels saturated, however the NAM is more aggressive. If freezing drizzle/light rain develops it will be along and south of the I-96 corridor and bring with it a light glaze of ice creating slick conditions.

- Another Round of Snow and Rain Tonight into Wednesday

A brief break in wintry weather is expected this afternoon but it will be short lived as another clipper system swings through the region tonight into Wednesday. This low will be stronger as seen in the 250mb upper level divergence and warming temperatures along with strong warm air advection near the surface with the low level jet. Positive vorticity advection moves in around 10pm along with the better moisture. Precipitation is expected to start out as snow, but strong warm air advection on the south side of the low is expected to transition the snow to rain. We'll need to monitor surface temperatures to see if a brief period of freezing rain will occur. How far north the rain spreads will depend on the overall low track. Additionally the track will also impact snowfall amounts. A slight shift of 50 miles can make a huge difference in this set up. At this time there is higher confidence in snowfall amounts of 4 inches or more along and north of the M-20 corridor with probabilities in the 60 to 90 percent range. Therefore have issued a Winter Weather Advisory from Oceana to Isabella County and northward for tonight into Wednesday afternoon. The 25th to 75th percentile highlight amounts of 3 to 7 inches in this area. If the low tracks further south the advisory may need to be extended southward. Any rain is expected to transition back to snow Wednesday morning with snow showers continuing into the afternoon.

Winds will be quite breezy with this system with gusts from the southwest around 30 mph expanding from south to north overnight into Wednesday morning then shifting to the northwest behind the low late Wednesday morning into the afternoon. This will aid in reducing visibilities with the snowfall. The northwest flow off of the lake will also keep some snow shower in the area Wednesday afternoon and night, however moisture is limited so not expected much in the way of additional accumulations.

- Reinforcing short of Arctic Air and Snow Showers Fri-Sun

The coldest air of the season so far is showing up in some of the ensemble guidance over the weekend as another reinforcing clipper system may impact Michigan by Friday, bringing 850mb temperatures behind it into the -15C to -20C range Saturday and Sunday. This would yield high temperatures mainly in the teens to around 20F away from the lake. Upper low formation around or just north of Lake Superior is a possibility, with some vort maxes pivoting over the region which would help with synoptic lift and lake enhanced snowfall to areas along and west of US 131. This snow will likely be quite powdery and finer grain. Almost all ECE ensemble members show accumulating snow for the lakeshore region this weekend.

There are a few interesting takeaways from a global teleconnections standpoint this month. The weak La Nina pattern continues, and the Madden Julian Oscillation just moved out of a strong Phase 7 and decent strength Phase 8, which correlate to colder than normal temperatures across the northern U.S. Additionally, as we ended November and moved into December, a sudden stratospheric warming event occurred which is most easily tracked via a weakening and reversal of winds at 10mb across 60N latitude. The winds did not really reverse as they do during major SSW events, but still this had the effect of weakening the polar vortex and shifting it off the pole. While we haven't gotten the full brunt of the polar vortex here in Michigan, it likely has played some sort of role in modifying the tropospheric weather pattern across our broader region. All this to say is that one of the coldest starts to December on record (top 10 for all climate sites through the first week) is attributable to some of these factors.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 1259 AM EST Tue Dec 9 2025

MVFR dominates the pattern this afternoon with gust southeasterly winds. Winds have gusted upwards of 33kts. Expect this gusty winds to continue with a lull in the winds between 22Z to 03Z.

Snow is still expected to move in from the southwest between 00Z to 03Z tonight with a transition to a rain/snow mix to rain along and south of the I-96 corridor into Wednesday morning. Freezing rain remains possible during the transitions. Snow is expected again early Wednesday morning with a transition from rain to snow. IFR cigs are expected after 00Z with ceilings improving slowly tomorrow.

Ceilings will improves from the Northwest to southeast behind the front late tomorrow morning, early afternoon. Vsbys will remain MVFR and lower with periods of IFR vsbys possible with Fog/mist due to the rain/snow transition around 14Z Wednesday. LLWS is expected after 07Z until around 12Z due to the approaching front at GRR, AZO, BTL, LAN and JXN.

MARINE

Issued at 338 AM EST Tue Dec 9 2025

Gales will taper off after sunrise with Small Craft Advisory conditions continuing through the day. Strong southwest winds then move in tonight into Wednesday bringing another period of gales. Winds will shift to the northwest Wednesday afternoon as the strong low pressure system shifts east. Wave heights during this time are expected to be in the 7 to 12 foot range. Gales subside Wednesday evening with Small Craft Advisory conditions likely through at least Thursday.

GRR WATCHES/WARNINGS/ADVISORIES

MI...Winter Weather Advisory from 10 PM this evening to 4 PM EST Wednesday for MIZ037>040-043>046. MARINE...Small Craft Advisory until midnight EST tonight for LMZ844>847. Gale Warning from midnight tonight to 7 PM EST Wednesday for LMZ844>847. Small Craft Advisory until 7 AM EST Wednesday for LMZ848-849. Gale Warning from 7 AM to 7 PM EST Wednesday for LMZ848-849.