textproduct: Grand Rapids

KEY MESSAGES

- Lake Enhanced Snow This Afternoon and Evening

- Snow Sunday Night into Early Monday

- Milder and Drier Much of Next Week; Wetter Late?

DISCUSSION

Issued at 258 PM EST Thu Jan 1 2026

- Lake Enhanced Snow This Afternoon and Evening

Once again, the lake will be providing a boost to some synoptic scale light snow moving over the region this afternoon and evening. Observations across WI this afternoon indicate 1-2 miles in light snow. Preexisting lake effect clouds and snow showers here are perking up as deeper moisture (1000-700mb RH values reaching 90-100%) moves in and periods of decent lift at and below the DGZ occurs while the DGZ itself becomes nearly isothermal for a depth of almost 10k ft through 00z (per 12z HRRR Bufkit soundings at GRR). This is thanks to the synoptic scale moisture and falling flakes above 5k ft into the lake modified boundary layer. The deeper moisture and at least some modest lift hangs around through about 03z before decreasing. Snow showers will likely be fairly persistent until then although rates may top out at a quarter inch per hour, maybe a half inch per hour under the heaviest bands.

The current surface analysis shows wind convergence occurring near and west of US 131. Low level convergence may help aid in some snow shower intensity for a time this afternoon and evening. With primarily WNW to W low level flow off the lake, some of the steadier snow bands will likely be impacting Muskegon, Kent, Ottawa, and Allegan Counties. After loading in the latest 12z high resolution guidance, QPF amounts have nudged up along and west of US 131 compared to the 00z guidance. Cobb SLRs are quite high for sites such as BIV and GRR (30:1 or even close to 40:1 at times) but WPC SLRs are lower (20-25:1), which we're favoring at this point. This produces 1"-2" through this evening with some spots in the 2"-3" range. Given the areal average will likely be 1"-2" total we are not planning on an Advisory, though slick travel is likely for some areas given falling snow and temps in the teens making road treatment more challenging. Allow extra time to reach your destinations this evening.

- Snow Possible Sunday Night into Early Monday

It is looking more likely than not that the next system slated to impact the region Sunday night into early Monday should stay all snow, with Central Lower Michigan currently favored. A coupled upper jet structure arrives as part of a coastal California system moves toward the Great Lakes at a rapid pace between Saturday and Sunday, arriving in the upper levels as seen on the 250mb upper jet plot and 500mb height/vort plot but also the MSLP/precip fields. While 850-925mb temps try to make a run at above 0C across Lower MI, the warm layer likely won't get here until after the precipitation ends. As a result this system will likely just be a snow producer but can't totally rule out some light sleet or freezing rain across southern Lower MI if temps aloft warm with subsequent model runs. ECE 24hr QPF 50th percentile is showing 0.10"-0.25" along and north of I-96. ECE probability for 1" or more of snow is 40-60% along I-96 and 80-100% along US 10. This won't be a major snow producer but could impact the Monday morning commute especially near and north of I-96.

- Milder Next Week; Wetter Late?

Ensemble guidance is generally in good agreement regarding moderating 850mb temps next week and some rising upper heights, with an occasional shortwave ripple in the flow that could bring light (mainly liquid) precip to the area. Highs are favored to range from the mid 30s to low 40s. By Thursday into Friday, there is some indication for a deep SW flow pattern trying to take shape across the central CONUS and this could bring some anomalous PWAT values to the area along with a risk for rain or mixed precipitation by week's end.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 1137 PM EST Thu Jan 1 2026

No significant changes from previous thinking. As expected, visibilities are increasing areawide into VFR territory as snowfall continues to diminish in intensity. Probabilities of IFR thresholds being met overnight continue to shrink, now estimated at less than 20 percent. The main question now is whether ceilings will remain above fuel alternate thresholds (2000 ft AGL) overnight. Some guidance suggests we will see at least a brief drop below that level and have included that in this update.

GRR WATCHES/WARNINGS/ADVISORIES

MI...None. MARINE...Small Craft Advisory until 7 PM EST Friday for LMZ844>849.