textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Widespread frost across southern WI early this morning. Additional frost chances Tonight/Friday morning for inland WI, especially towards central WI.

- Small chances (10-30%) for scattered light rain showers in the daytime hours Today thru Saturday.

- Warmer temps Friday and Saturday (highs in the 60s, then closer to 70).

- Roughly 60% chances for light rainfall next Tuesday.

UPDATE

Issued 530 AM CDT Thu May 7 2026

Latest model trends have trended drier but the NAM seems to be capturing at least where echoes exist and given the surface being not terribly dry there is at least a chance some of this is reaching the surface. This also lends some credence to the NAM for the rest of today and thus despite the drier trend we will maintain the 20-30% chances for much of the CWA today for a shower and maybe even a rumble of thunder. Otherwise a frosty morning but is expected to rise to the upper 50s today.

Kuroski

SHORT TERM

Issued 100 AM CDT Thu May 7 2026

Today and Tonight:

The Frost Advisory remains in effect through 8 AM CDT this morning, with overnight low temps expected to bottom out in the low 30s to around 30 degrees flat. Some areas could easily fall to the upper 20s, particularly west of a Green Lake to Burlington line (where clouds cleared out faster this evening).

Daytime highs in the 50s to around 60 expected this afternoon (warmest towards southwest WI). A westerly breeze around 10 MPH occasionally gusting to 20 in the afternoon will kick in later this morning, subsiding late in the afternoon. A southeasterly lake breeze may push back against it, confined to the immediate shoreline until the prevailing winds subside later in the afternoon.

A passing 500mb trough and a pocket of cooler air aloft may form some open cellular (popcorn-style) light rain showers out of the broken high-based cumulus clouds today, though we've reduced rain chances to 10-30%. For most areas, these rain showers should evaporate before reaching the ground. A stray rumble of thunder cannot be completely ruled out, but is growing less likely with time (15% chance or less). Rain chances and cloud coverage erode quickly as the sun angle decreases this evening, leaving dry weather and mostly clear skies tonight.

Sheppard

LONG TERM

Issued 100 AM CDT Thu May 7 2026

Friday through Wednesday:

Ensemble temperature plumes show a continued warming trend Friday into Saturday, with light southwesterly winds and a chance for a shoreline lake breeze Friday, followed by modest southwest winds and no lake breeze Saturday. The warmth should peak Saturday afternoon with highs in the upper 60s to around 70. Broad high pressure over the southeastern CONUS and broad low pressure over central Canada should form a zone of confluence / strong low to mid level WAA over IL on Friday, with only 5-15% chances for stray shower activity from that to meander into southern WI. For Saturday, a shortwave trough and cold front (extending southwest of the Canadian low pressure) sweep southeastward across Wisconsin, with the surface to 700mb WAA refocusing over our region Saturday morning followed by the frontal passage sometime in the afternoon (plenty of dispersion on the exact time). There will be chances for scattered light rainshowers ahead of and along the front (through the daytime hours Saturday), but the latest model guidance decreases Saturday's precip chances from ~45% to ~25% on account of a drier and well mixed PBL ahead of the front. For both the Friday and Saturday shower chances, a few rumbles of thunder cannot be completely ruled out, but storms are expected to be weak if applicable, and ensemble + deterministic model CAPE has decreased since the last forecast iteration. As such, the "slight chance of thunder" wording has been removed from the forecast for now.

High temperatures fall into the 50s to around 60 behind the front on Sunday, with a northwest synoptic breeze and shoreline lake breeze possible. Passing high pressure and weaker winds on Monday should allow for a more progressive lake breeze (at least 1 county inland, progressing further late in the afternoon), keeping shoreline temperatures in the 50s, though inland temperatures moderate upwards a few degrees. The slow warming trend continue through mid next week.

The only substantial precip chance through the forecast period is Tuesday (~60%) on account of a passing clipper system, with a relatively good consensus between GFS/ECMWF guidance. The fast moving nature of this system ought to limit the expected QPF, with the GEFS only resolving 10-20% chances of reaching half an inch. The arrival time and intensity of this system will continue to be monitored.

Sheppard

AVIATION

Issued 530 AM CDT Thu May 7 2026

VFR TAF period is expected with modest west winds and a chance for a shower today and maybe a rumble of thunder. Either way CIGS and VSBYS expected to remain VFR with no concerns into Friday either with modest west to southwest winds. There is a small chances for the lake breeze to kick in near the lake but would not be expected to make it very far west.

Kuroski

MARINE

Issued 100 AM CDT Thu May 7 2026

High pressure around 30.0 inches will continue to work south- southeastward across the central Plains with light and variable winds continuing over Lake Michigan overnight. South to southwesterly winds will develop for Thursday and continue through Saturday as the high pressure slides further southeast across the Lower Mississippi River Valley. However, winds will then increase ahead of a developing low pressure around 29.5 inches tracking north of the Great Lakes into Quebec for Saturday before dragging a cold front southward across Lake Michigan later in the day. Winds shift to the north-northwest behind the front for Sunday while high pressure around 30.2 inches builds down across the region into the start of next week.

Sheppard

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 until 8 AM Thursday.

LM...None.