Marine Weather and Tide Forecast for Athens, WI

DISCUSSION
Issued at 1205 AM CDT Fri May 16 2025

A warm and windy day is in store for today. The low will be over northwest MN at 7AM this morning and should make it to Duluth around 7PM. A lobe of vorticity is expected to swing up from IA through eastern WI during the day. Vorticity advection and also upper divergence from the left exit region of an upper jet will provide synoptic forcing to allow for showers and storms.

Forecast soundings show very steep low and mid level lapse rates during the afternoon, with 500 to 1000 j/kg CAPE. Some models show a weak cap while others try to mix us all the way up to 10kft. The winds through the profile are very strong with SW winds up to 43kt at 5kft and 50 to 60kt at 10kft. There will probably be a weak cap that will help keep our wind gusts in check today, but a few gusts over 39kt (wind advisory criteria)
are not out of the question. If gusts begin to over-achieve by noon today, we will know we need a wind advy for the afternoon.

Despite the weak cap, the overall synoptic forcing should be enough for scattered thunderstorm development. The CAPE values and low freezing level of 9 or 10kft support the chance for small hail, with a report of two of 1 inch hail possible. There is strong shear. The main threat for any stronger storms that develop is the damaging wind potential, since the strong winds aloft will efficiently mix down with momentum transfer.

As the upper low tracks across MN today, another frontal boundary will push into north central and eastern WI. This will feature cooler temperatures, low clouds, and rain or drizzle.
Northern WI will be fully engulfed in these damp, brisk conditions Friday night.

Saturday, expect breaks in the clouds as the upper low starts to exit the region. With steep low level lapse rates and lingering low level moisture, scattered showers are expected, although coverage is still uncertain. In addition, expect gusty west winds up to 30 mph during peak daytime heating/mixing. Saturday highs will range from the upper 50s north central to the mid 60s east.

MRC

Saturday night through next Thursday

Upper trough exits across the eastern Great Lakes Saturday night with ridging aloft beginning to build from the plains into the western Great Lakes. Surface high pressure over Manitoba and northern Ontario will ridge into MN and WI Saturday night with more influence of ridging by Sunday night.
The ridge will bring dry weather and also the risk of frost Saturday night and/or Sunday night. PWATs lower Sunday night, but with high more off to the north than the east, the area will keep some wind in lowest 1kft with tighter pressure gradient on southern edge of high. It still appears that temps could drop into the mid 30s north Saturday night and/or Sunday night. NBM probabilities of min temps less than 35 are 30 to 40 percent Saturday night over Vilas County, but increase and expand to 40-80 percent Sunday night north of highway 29. If and where winds become light, some frost could occur either of these nights, though Sunday night looks more favorable at this point.

Troughing over the western CONUS late this weekend shifts east early next week, bringing the next chance of showers and storms to the area Monday night into Tuesday. One trend that seems to be emerging though is the dry east flow out of the high to the north may restrict chances of rain only to the southern part of the forecast area on into southern WI. Risk of any stronger storms also is well to the south of the area. Given these trends, its feasible that much of northern WI could stay dry early this week. Whatever chances of rain occur will shift south and east of the western Great Lakes Wed into Thu as broad 850-700mb low shifts across lower Great Lakes. Cool flow in wake of the low flowing across the region could lead to more clouds and a small chance of spotty showers by Thursday. Overall a cooler than normal stretch is expected for the coming week with highs in the upper 50s to mid 60s.

JLA.

AVIATION
for 18Z TAF Issuance Issued at 1249 PM CDT Fri May 16 2025

Mostly clear skies and VFR conditions were observed for most early this afternoon; however, satellite imagery shows mid-clouds starting to enter central WI. The main feature was the winds with SSW gusts to around 30 kts.

Scattered showers and thunderstorms are likely to develop this afternoon, but exact location is difficult to pinpoint. Coverage will not be as widespread as yesterday, but the chance (30-45%)
exists everywhere. Main time window is 20Z-24Z. Included TEMPO groups to account for this. Precip chances will be minimal the rest of the evening into Saturday morning. A few spotty showers are possible, but coverage/confidence was too low to include in TAFs this issuance.

Cloud bases will lower late this evening with a mix of MVFR/IFR cigs tonight (approx. 06Z) through Saturday morning. Winds will also increase again and peak late Saturday morning through the afternoon with gusts up to 30 kts.

MARINE
Issued at 1205 AM CDT Fri May 16 2025

Gusty south-southwest winds are expected today, highest over land. Cooler lake water should keep wind gusts below gale force, so a Small Craft Advisory goes into effect mid morning.
We initially set the end time of 7PM this evening, but after a brief lull in the winds tonight, gusty westerly winds will develop. Therefore, we extended the end time all the way until 7PM Saturday.

MRC.

GRB WATCHES/WARNINGS/ADVISORIES
None.