Area Forecast Discussion

KEY MESSAGES

- Severe risk is decreasing and remains confined to counties adjacent to the Wisconsin Illinois state line.

- Flash flooding of urban and slow drainage areas is expected with thunderstorms. A Flash Flood Watch is in effect through this evening.

UPDATE

Issued 530 PM CDT Thu Jun 11 2026

The instability surge to the north has not manifested itself and the atmosphere has shown its cards. Showers and thunderstorms will continue to expand into the area over the next few hours and exit from west to east, ending in (roughly) the 8 PM hour.

Low level shear is enough to remain on guard with convection entering from Illinois. To this point, we have been sufficiently capped with few gusts reported (at best 20mph). Will need to keep an eye on the potential for a few wet microbursts with the strengthening activity along the straight line. As a result cannot completely rule out a few severe storms. The tornado risk continues to decrease with time given the surface based instability remains shunted to our south. Will maintain the watch given ongoing activity and trim as activity exits.

Very moist airmass with large warm cloud depths and high precipitable water have resulted in heavy rainfall as well, with rates exceeding 1-2 inches in the heavier downpours. The flash flood risk in urban and slow drainage areas will persist until this activity exits to the east.

Gagan

SHORT TERM

Issued 151 PM CDT Thu Jun 11 2026

Tonight and Friday:

A very challenging forecast for the rest of today. The mesoscale is interesting, but quite messy for a number of factors.

The first challenge is the lingering effects of the showers/storms that moved through the area this morning. This has overturned our airmass a bit and currently low level lapse rates and instability are suffering. That said, we do have a solid mid level wave becoming negatively tilted and a surface low moving northeast into the area. This is more spring like forcing, which can lead to rapid low level airmass and instability recovery.

Guidance continues to suggest that airmass recovery will at least give it a try as forcing moves to the northeast. With considerable low level shear in place (very large effective low level helicity) it would not take much storm organization to pose a damaging wind and tornado risk.

At the moment we are targeting counties adjacent to the WI/IL state line for the best tornado potential if low level recovery occurs and instability responds. To the north of this area, any supercellular structures will pose a hail and damaging wind risk.

Finally, the airmass remains very moist and any storm will be capable of heavy rainfall with rates between 1-2 inches per hours. The good news is that this next round of rain/storms should be progressive, but urban and slow drainage areas will be at risk for flash flooding due to excessive rates.

Quiet weather is expected Friday as weak high pressure moves across the Midwest. Mainly clear skies and highs near 80 are expected.

Gagan

LONG TERM

Issued 151 PM CDT Thu Jun 11 2026

Friday night through Thursday:

Our next cold front and chance for showers/storms arrives during the Saturday afternoon into the evening hours. The best upper support and forcing has been located to our southwest with the past several runs of models. That said, there should be enough low level convergence with modest MUCAPE profiles and increasing shear to support scattered thunderstorms moving northwest to southeast across the area during the mid afternoon hours into the evening. SPC has the region in a marginal risk for a few storms that could produce marginally severe hail and localized gusty winds.

A digging trough over the eastern CONUS will result in quieter weather, with a sizable drop in dewpoints and a cooler airmass moving into the region. Northwest flow will send a few shortwaves through the region with some model agreement toward a more organized wave moving through the region in the late Tuesday through Wednesday time frame.

Gagan

AVIATION

Issued 151 PM CDT Thu Jun 11 2026

Primary concern for the this afternoon into this evening is the severe thunderstorm potential. Storms will develop to our west after 18z and move to the east through southern WI during the mid to late afternoon hours, exiting to the east after 02z. Very heavy rainfall and wind gusts will accompany these storms, lowering visibility and ceilings to IFR. Winds will shift to the west after storms exit and skies are expected to clear.

Gagan

MARINE

Issued 151 PM CDT Thu Jun 11 2026

Southwest winds will become breezy south to southeasterly this afternoon as low pressure around 29.5 inches moves from eastern Iowa to central Lake Michigan by early evening. By Friday morning the low will continue to accelerate northeastward into Ontario. Winds will become westerly and breezy behind the low pressure area this evening through the overnight. Numerous thunderstorms are expected this afternoon and evening and may become severe.

A small craft advisory is in effect from this afternoon through tonight for wind gusts and elevated waves. Highest waves toward Sheboygan.

Gagan

MKX WATCHES / WARNINGS / ADVISORIES

WI...Flood Watch...WIZ046-WIZ047-WIZ051-WIZ052-WIZ056-WIZ057-WIZ058- WIZ059-WIZ060-WIZ062-WIZ063-WIZ064-WIZ065-WIZ066-WIZ067- WIZ068-WIZ069-WIZ070-WIZ071-WIZ072 until 11 PM Thursday.

LM...Small Craft Advisory...LMZ643 until 4 AM Friday.

Small Craft Advisory...LMZ644-LMZ645-LMZ646 until 11 PM Thursday.