Marine Weather and Tide Forecast for Ephraim, WI

DISCUSSION
Issued at 100 AM CDT Sun May 31 2026

Precipitation Chances...A strong ridge of high pressure is expected to dominate the weather pattern through at least the middle of next week, keeping conditions dry. The only minor intrusion that some guidance is hinting at is a subtle shift of the persistent stationary moisture to the southwest of the region moving into the southwest portion of the forecast area Sunday night into Monday. If this occurs, a few light rain showers or sprinkles may occur across central Wisconsin; however, dry air from the prevailing high pressure should keep conditions dry.

By Wednesday night, the upper-level ridge will flatten and the high pressure will slide eastward as a shortwave trough approaches from the northern Plains. Beginning Thursday, the pattern becomes unsettled with multiple chances for showers and thunderstorms through next weekend. Since there are still some timing issues, it is too early to determine any severe potential at this time.

Temperatures...High temperatures are expected to be a few degrees above normal through Tuesday with highs around 80 away from the lakeshore. Temperatures will then increase to about 10 degrees above normal by Wednesday as highs increase into the 80s across the region, which is expected to last into next weekend.

The threat of high temperatures of 90 or greater will be small (less than 20%) through the middle of the week. This is expected to increase to 20 to 40% by late next week into the weekend across central Wisconsin, the Fox Valley, and far northeast Wisconsin.

AVIATION
for 12Z TAF Issuance Issued at 531 AM CDT Sun May 31 2026

VFR conditions will prevail through the TAF period as high clouds continue to filter over the region. Light and variable winds early this morning will become south-southeast later this morning, mainly under 7 kts. A lake breeze is likely to develop this afternoon, which would turn winds easterly along and near the Lake Michigan shoreline (KMTW) with gusts of up to 15 kts as the lake boundary pushes inland.

There is a low-end (10%) for scattered showers across western Wisconsin west of an KEAU to KMSN line, early Monday morning, that could shift east into parts of central Wisconsin; however, any aviation impacts should be minimal.

FIRE WEATHER
Issued at 100 AM CDT Sun May 31 2026

Until a widespread wetting rain occurs, elevated fire weather conditions will continue through much of next week as afternoon RHs will routinely drop to 20 to 30% or lower with temperatures in the 70s/80s. Despite green up progressing and/or completing, fuel input from fire partners points to concern where recent dryness persists, any days with increasing winds could allow the fire weather potential to rise to near-critical. The best potential could be the middle to late part of next week as the lower RH values could coincide with increasing gradient winds as the prevailing high pressure exits east and a shortwave/trough approaches from the northern Plains.

GRB WATCHES/WARNINGS/ADVISORIES
None.