textproduct: Milwaukee/Sullivan

KEY MESSAGES

- An Extreme Heat Warning remains in effect for portions of south central and southeast WI into this evening. Additional heat headlines are not anticipated the remainder of this week.

- Developing line of storms over ne IA is expected to move across srn WI late this afternoon and evening. Damaging winds is the main threat with a low potential for QLCS tornadoes. - Flood Watch for Sauk County until 7 AM CDT Fri for a flash flood potential given the 2 to 3 inches of accumulation today, and expected thunderstorms from late this afternoon through tnt.

- Showers and thunderstorms chances of 50-80 percent continue for Fri-Sat but with lessening severe thunderstorm chances.

SHORT TERM

Issued 159 PM CDT Thu Jul 2 2026

Tonight through Friday night:

The developing MCS over ne IA is expected to move ewd across srn WI late this afternoon and evening. MLCAPE may rebound to 2000 J/KG as far north of Madison and Milwaukee with lower amounts and higher MLCIN to the north. Wly 0-3 KM shear around 30 kts is expected yielding the potential for mesovortex generation and associated damaging winds and isolated tornadoes. Afterward, additional showers and storms can be expected as a swly low level jet around 30 kts develops ahead of a shortwave trough moving from nrn IA and srn MN across WI. This will likely yield more of heavy rain threat. Given the 2-3 inches of rain today over Sauk County, issued a Flood Watch for potential flash flooding but lesser chances elsewhere due to drier antecedent conditions.

Another shortwave trough will approach from MN Fri AM and drift across nrn and central WI during the day. CAMs also have a MCS with this feature but many weaken it as it moves into srn WI. Given the morning timing and the better instability shifting the the south, this is plausible. Rain chances of 50-80 percent over south central WI and 50 percent over se WI. Some development in the afternoon is possible. Additional shortwave troughs are expected for the weekend but with lesser instability and near normal temperatures each day. Rain chances of 60-80 percent on Sat falling to 20-40 percent for Sun.

Gehring

LONG TERM

Issued 159 PM CDT Thu Jul 2 2026

Monday through Thursday:

Weak nwly flow aloft and high 500 mb heights will prevail next week. Warm and humid conditions typical of July are forecast. Weak shortwave troughs within the flow will bring 20-40 percent chances of showers and storms at times.

Gehring

AVIATION

Issued 159 PM CDT Thu Jul 2 2026

Sct-bkn035-045 cumlus will develop late this afternoon ahead of a line of storms approaching from ne IA. This line of storms will move east across srn WI late this afternoon and evening and possibly be followed by additional storms during the night. AT least scattered showers and storms are then forecast for Fri. Patchy MVFR Cigs and Vsbys can be expected in the wake of storms at times.

Gehring

MARINE

Issued 159 PM CDT Thu Jul 2 2026

Large high pressure around 30.1 inches will remain parked over the Ohio Valley and Appalachian Mountains into Friday night. Meanwhile, a trough of low pressure will remain over the Great Plains today into Friday night. A weak low pressure area may then organize and slowly move across Wisconsin and Lake Michigan from Saturday afternoon into Sunday, or pass farther south across Illinois into the Ohio Valley. Modest south to southwest winds will persist today becoming a bit lighter tonight and Friday. Light to modest winds are then forecast for the weekend, but with some uncertainty on wind direction given low confidence in the track of the low. A stormy period is expected for central and southern Lake Michigan from tonight into the weekend. Patchy marine fog will be possible at times as warm and humid air flows over the relatively cooler lake.

Gehring

MKX WATCHES/WARNINGS/ADVISORIES

WI...Flood Watch...WIZ056 until 7 AM Friday. LM...None.