textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Widespread frost across southern WI tonight/Thursday morning with additional frost chances Thursday night/Friday morning for inland WI.

- Chances (20-50%) for showers and thunderstorms each day Thursday through Saturday, but rainfall is expected to be light with this activity.

- Warmer temps Friday and Saturday with highs in the 60s-70s.

UPDATE

Issued 730 PM CDT Wed May 6 2026

With the current temperature observations remaining on track with the forecast, the Frost Advisory remains in effect tonight into Thursday morning (1 AM to 8 AM Thu) for the entire region. The only lingering piece of uncertainty with regards to the frost is how quickly the existing ~6,000 ft stratocumulus clouds (mainly north towards central WI) will continue to erode, and how soon a second batch of clouds will arrive from the west Thursday morning (around dawn or ~1 hour predawn). Short range model consensus suggests we've got plenty of time for radiational cooling overnight, with low temps in the low 30s.

Sheppard

SHORT TERM

Issued 150 PM CDT Wed May 6 2026

Tonight through Thursday night:

Upper-level low continues to sit over the Hudson Bay region bringing northwesterly flow pattern across the region into the weekend. Will continue to see cooler temps tonight with this pattern tonight into Thursday as northwest to westerly low-level winds prevail ahead of the surface high working its way across the Central Plains. Thus looking at another night of frosty conditions across inland portions of southern WI with lows in the lower 30s. While some concerns with the cloud cover limited the spread of frost development, given the trends still think it will drop cold enough especially with any breaks in the clouds. Thus issued a Frost Advisory for much of inland southern WI counties.

High pressure over the Plains extending into the region will gradually slide south-southeastward for Thursday. Winds are looking more westerly to southwesterly component. Thus looking at a bit warmer temps with the beginnings of low-level WAA and temps climbing into the upper 50s and back into the 60s.

However, looking at a mid-level ripple of vorticity to work across the area during the afternoon. This with the low-level look to be enough to spur a scattered showers development through the afternoon. Cloud cover may limit temps a bit with this activity, but still a bulk of the 12z HREF members ping enough SBCAPE (50-200 J/kg) to add mentions for isolated thunderstorms from the afternoon shower activity.

Thursday night will be slightly warmer with lows in the mid 30s to around 40F as WAA and southerly flow increases across the area, but still looks to be areas of frost northwest of HWY-151 with patchy coverage further south and east. So may need another frost headline.

Wagner

LONG TERM

Issued 150 PM CDT Wed May 6 2026

Friday through Wednesday:

Continue to see temps gradually warm up for Friday and Saturday with the persisting low-level WAA over the region. However accompanying the the warmth will also be a few chances for showers and maybe a few isolated thunderstorms. Friday chances main driver will be another shortwave trough rounding the base of the upper-level trough along with low-level WAA. While the better forcing and chances continue to trend south of the WI/IL border, still looks to be enough of the forcing and moisture to creep north into our neck of the woods with 15-30% chance. While thunderstorm are looking less likely cannot rule of a few rumbles of thunder as well.

Saturday is looking to be the warmest day of the weekend with highs creeping into the upper 60s and lower 70s. This warmer setup and increased slug of Pacific moisture ahead of another, stronger mid- level shortwave trough will bring better shower and thunderstorm chances to the area later in the day. The associated surface low is progged to trek across eastern Ontario and in to Quebec dragging a west to northeast orientated cold front southward down across the region. Moisture parted with a meager amount of instability may be enough to trigger a few thunderstorms with this round of showers.

Then things cool down behind the frontal passage for Sunday lingering into the start of next week as high pressure is progged to build into the region. Then the pattern looks to warm back up toward the middle of next week as the pattern becomes more progressive as the upper- level trough finally kicks eastward allowing additional trough to dig across the region through the middle of the week.

Wagner

AVIATION

Issued 730 PM CDT Wed May 6 2026

The west-northwest breeze and broken stratocumulus cloud cover are both expected to erode through this evening over southern WI, leaving dry weather, VFR conditions, and nearly calm winds overnight.

The breeze resumes out of the southwest Thursday morning, veering due west. Sustained winds around 10 kts expected, with a few gusts to ~20 kts in the afternoon. A southeasterly lake breeze will attempt to push against these prevailing winds early/mid afternoon (and might reach shoreline terminals); it should make more inland progress as both wind fields subside late Thursday afternoon / Thursday evening. A 20-40% chance for rain is forecast through the daytime hours Thursday (mainly between 10 AM and 6 PM CDT), and would be popcorn style / scattered showery activity. A stray rumble of thunder cannot be completely ruled out, but has been left out of the PROB30 groups of TAFs for now.

Sheppard

MARINE

Issued 150 PM CDT Wed May 6 2026

High pressure over the Plains continues to track south and east turning west winds to south-southwest while remaining lighter across Lake Michigan through the end of the week. Friday night into Saturday looks at the southerly winds to pick up ahead of an incoming cold front along with increased shower/thunderstorm chances. Expect this southward moving cold front to turn winds more northerly behind it later Saturday into Sunday as high pressure builds across the region for the start of next week.

Wagner

MKX WATCHES/WARNINGS/ADVISORIES

WI...Frost Advisory...WIZ046-WIZ047-WIZ051-WIZ052-WIZ056-WIZ057- WIZ058-WIZ059-WIZ060-WIZ062-WIZ063-WIZ064-WIZ065-WIZ066- WIZ067-WIZ068-WIZ069-WIZ070-WIZ071-WIZ072...1 AM Thursday to 8 AM Thursday.

LM...None.