Marine Weather and Tide Forecast for Athens, WI

DISCUSSION
Issued at 235 AM CST Sat Nov 29 2025

The latest RAP analysis and satellite imagery show shortwave energy digging southeast across the central Rockies early this morning, while flow aloft remains relatively flat across the Midwest. Surface low pressure is currently centered over southeast Colorado. Ahead of this low, broad warm and moist advection is occurring in the 850-700mb layer, supported by a 40 kt low-level jet nosing into Iowa.
Saturated conditions in the 900-800mb layer are occurring as close as northeast Iowa and southern Minnesota where snow is occurring.
As the shortwave energy moves from the Rockies across the Plains today, the surface low is progged to track from central Kansas to the Iowa/Missouri/Illinois border by early evening, eventually reaching the central Lower Peninsula of Michigan by 6 am Sunday.
This track will bring the Colorado Low northeast across the region over the next 24 to 36 hours.

Short Term (Today through Sunday):

Winter Storm: Focus of the forecast revolves around snow accumulations and impacts as the low pressure system traverses the region. Ascent will increase today via warm advection driven by a 40-50 kt low- level jet moving into northern Illinois, coupled with upper divergence in the right rear quadrant of a jet streak.
Light snow will gradually spread from southwest to northeast across the region this morning through mid-afternoon. High- resolution CAMs indicate a mid-lake band becoming organized later this morning and moving onshore into the northeast WI shoreline by early afternoon. Precipitation intensity is expected to increase significantly across the region this afternoon and evening. It is noted that snow ratios were lowered for this forecast as the NBM tends to have a high bias in warm advection regimes. While QPF has trended steady, values were adjusted lower compared to the NBM, which was running at the 75th percentile of guidance.

The heaviest snowfall is expected to target east-central Wisconsin from late this afternoon through this evening. This intensification is attributed to multi-bands of lake enhancement interacting with a focused band of frontogenesis that several models develop from Waushara to Manitowoc counties. Delta-Ts upwards of 15-17C and a deep dendritic snow growth zone (100-150mb deep) should lead to efficient snowfall production. Consequently, locally higher amounts are possible near Lake Michigan, particularly over Kewaunee and Manitowoc counties where totals may exceed 12 inches.
Some amounts could also approach 12 inches from Waushara to Calumet counties as well if a mesoscale snowband becomes focused.
The heaviest snow will depart after midnight, with snow ending for most areas Sunday morning. However, lake effect snow will likely continue in the snow belt of Vilas County, where snowfall estimates have increased to the 2-4 inch range. As a result, the Winter Weather Advisory has been expanded into Vilas County.
Regarding timing of headlines, the start time of the advisory has been delayed until noon, and the warning until 10 am, as impacts from snowfall looks minimal prior to those times.

Sunday Impacts and Winds: While the accumulating snow will diminish Sunday morning, travel impacts will likely continue.
Northwest winds are forecast to increase just as the synoptic snow departs, with gusts of 30 to 35 mph possible. These gusts will be strongest where the heaviest snow is expected to fall, specifically from the southern Fox Valley to the Lakeshore.
Blowing and drifting snow is likely, particularly on east- west oriented roads. A Winter Weather Advisory may be needed on Sunday as the snow diminishes and blowing snow hazards increase; however, there is currently no need to extend the Winter Storm Warning as little to no additional snow accumulation is expected Sunday morning. Highs on Sunday will range from the lower 20s to lower 30s.

Long Term (Sunday Night through next Friday):

A winter-like pattern is shaping up across North America for the next week, characterized by 5-day means showing ridging off the west coast and troughing extending from Hudson Bay to the Great Lakes. 850mb temperatures indicate below-normal readings, setting the stage for the coldest air of the season thus far. Sunday night into Monday will see wind chills falling to around 10 below zero, with highs on Monday in the teens. Looking ahead, the system previously monitored for Monday night continues to trend northward, though snow chances continue to slowly rise to above 30 percent, highest over east- central Wisconsin. By Wednesday, an arctic front will produce the next widespread chance for snow (40 percent). Amounts with this mid- week system look relatively light, generally an inch or two.
Arctic high pressure is then expected to build in for late in the week.

AVIATION
for 18Z TAF Issuance Issued at 1132 AM CST Sat Nov 29 2025

Poor flying conditions expected through tonight due tn snow, which may be heavy at times, and low CIGS varying from MVFR or IFR. Conditions may drop below the IFR category due to heavy snow shower activity along the Lake Michigan shoreline, which could impact KMTW and airports across Door County. Snow will gradually taper off from west to east late tonight, except across the north where snow showers linger into Sunday. Snowfall totals of 3-6 inches expected across the north, with 6 to 12 inches south of a Wausau to Wausaukee line. Behind the system, gusty northerly winds expected on Sunday that could produce some blowing and drifting of the new snow. Winds should gradually subside Sunday afternoon.

GRB WATCHES/WARNINGS/ADVISORIES
Winter Weather Advisory until 6 AM CST Sunday for WIZ005-010>013- 018-019-021.

Winter Storm Warning until 6 AM CST Sunday for WIZ020-022-030- 031-035>040-045-048>050-073-074.