Area Forecast Discussion

KEY MESSAGES

-Minor to moderate flooding continues on many rivers, with major flooding expected on the Wolf River through Tuesday. Water levels have crested in most areas, and due to an extended period of dry weather, a gradually drop is anticipated through the week.

-Showers and thunderstorms are likely Thursday night into Friday. With a low end (5-15%) chance for strong to severe storms, mainly across central and north-central WI.

-Temperatures will be be below normal through Monday, with much above normal temperatures in the 60s and 70s expected Tuesday through Friday.

DISCUSSION

Issued at 151 AM CDT Sun Apr 19 2026

Continued northwesterly flow today will keep temperatures well below normal. Highs this afternoon are only expected to reach the middle 30s across northern WI to the upper 40s in the Fox Valley. A subtle short-wave, currently over western MN, passing through the broader upper trough will bring a slight chance (10-20%) for scattered flurries across central and east-central WI this morning. A dusting of snow accumulations on grassy surfaces is possible, however, don't expect any travel impacts. Forecast soundings for today also show the PBL becoming deeply mixed, up to 8kft, which will lead to a substantial decrease in dew points, especially across northern WI.

The first half of next week will be dominated by upper-ridgeing leading to mostly dry and near to above normal temperatures. Medium range ensembles do show a cold front sweeping across the region Monday which could kick of scattered sprinkles across northern WI, however, with such a dry airmass in place think this will be a dry frontal passage for most locations.

Main focus of the extended forecast is late Thursday into Friday and the next chance for widespread showers and thunderstorms move into the western Great Lakes. Mean upper-level flow fields show a broad trough developing over the Northern Plains which drags a cold front through the forecast area Thursday night into Friday. Ahead of the front substantial northward moisture transport will increase PWATS to 1.2-1.3", which is over the 99th percentile of climo. The increase in moisture also leads to moderate destabilization with mean MUCAPE values increasing to 800-900 J/kg. This would create an environment favorable for stronger thunderstorms and locally heavy rainfall. If you have travel or outdoor plans Thursday evening or Friday make sure to monitor the forecast as details become more clear.

AVIATION

for 18Z TAF Issuance Issued at 1219 PM CDT Sun Apr 19 2026

A few sprinkles of flurries will come to an end early this afternoon, but high-based stratocumulus clouds will persist until about sunset. Mostly clear skies and light and variable winds are expected tonight, with an increase in high clouds and gusty southwest winds anticipated toward the end of the TAF period.

Looking ahead, LLWS is expected to develop across the area Monday evening.

HYDROLOGY

Issued at 151 AM CDT Sun Apr 19 2026

Minor to moderate flooding continues on many rivers, with major flooding expected to persist on the Wolf River through Tuesday. Most of the river levels have crested, and with a prolonged stretch of dry weather anticipated through Thursday, water levels should gradually subside through the week.

Those living near rivers should continue to monitor the latest Flood Warnings and statements from the National Weather Service in Green Bay.

GRB WATCHES / WARNINGS / ADVISORIES

None.