Area Forecast Discussion

KEY MESSAGES

- Spotty light rain and sprinkles (30-60% chances) for Halloween. Rainfall amounts less than 0.10 inch.

- Unsettled conditions much of next week, with widespread showers (70-95%) and gusty winds Monday afternoon through Wednesday, peaking Monday night into Election Day. Shower chances lingers into Thursday. - The probability of 48-hour rainfall totals over 1" from Monday afternoon through Wednesday afternoon range from 60-75% north and west of the Fox Valley to 40-60% over Fox Valley east to Lake Michigan.

- Above normal temperatures continue through the middle of next week.

DISCUSSION

Issued at 1130 PM CDT Fri Oct 30 2026

Mid-level warm air advection across southwest WI is lifting an arcing band of showers toward central late this evening. However, with such a dry surface layer in place, don't anticipate more than a sprinkle reaching the ground overnight. As a surface low lifts closer to the region Saturday an draws addtioanl moisture into the region expect some isolated to scattered showers to develop during the afternoon and evening. Rainfall amounts will be fairly light with most places seeing only a few hundreths. High pressure then builds back in on Sunday returning dry conditions to the region to finish the weekend.

A slow moving, moisture-laden system arrives Monday afternoon/ evening and sticks around into at least Thursday. Rain is likely Monday night into Tuesday (80-95%) with the initial surge of moisture and forcing. Then chance/likely PoPs will continue into Wednesday, then taper off on Thursday as the system finally exits to our east. Chances for exceeding 0.50 inch rain Monday Night through Tuesday are 70-90% with chances for exceeding 1.00 inch between 70- 80% northwest of the Fox Valley, and 40-60% over east-central WI. Higher end projections take rainfall to 1.5 to 2.25 inches. Certainly looking like a soaking rain at times. Some elevated instability and impressive dynamics with the initial WAA surge Monday night to include some thunder, especially across central and north-central WI.

Temperatures will trend back above normal this weekend, with highs on Halloween mainly in the 50s and in the low to mid 60s on Sunday through Wednesday. Temps cool off behind the large system at the end of the week.

AVIATION

for 00Z TAF Issuance Issued at 642 PM CDT Fri Oct 30 2026

VFR conditions will continue this evening with as mid and high clouds spreading across the region, generally above 9 kft. Ceilings start lowering after 06Z as a low pressure system system over the central Plains moves closer to the region. MVFR ceilings will gradually begin to move into central WI Saturday morning, but sub 3 kft ceilings are not expected to arrive at AUW/CWA until after 18Z Sat. Patchy light rain and sprinkles will also be possible Saturday afternoon, but minimal impacts to ceilings/visibilities are expected.

Light and variable winds generally under 5 kts will continue this afternoon into tonight. Winds will become south/southeast on Saturday at 5-10 kts.

MARINE

Issued at 1130 PM CDT Fri Oct 30 2026

A slow moving low pressure system will move across the Great Lakes Monday night into Wednesday morning, bringing gusty south to southeast winds and large waves on the bay and Lake Michigan. A Small Craft Advisory will likely be needed. Winds will shift to the north on Thursday, possibly gusting to near 25 kts as the system departs to the east.

GRB WATCHES / WARNINGS / ADVISORIES

None.