Weather Lookup

Key Messages

- warm and humid conditions return thursday.

- chances for showers and weak thunderstorms at times from friday morning through friday night (65-85% chances). Chances gradually taper down through saturday.

Short Term

Issued 1154 PM CDT wed jul 29 2026

Rest of tonight through thursday night:

Expect more diurnal cumulus clouds thursday, increasing from west to east as dewpoints creep up into the lower 60S. Temperatures will be warmer, jumping into the upper 80S. While the heat indices will basically match the temperatures, it will feel very warm due to the light winds and sunshine.

While smoke is expected to be in the higher parts of the atmosphere, it should not hinder the surface visibility. The HRRR smoke model forecast for tomorrow is only showing values for vertically integrated smoke that we already had today, which did not cause reduced visibility.

Thursday night lows will be in the mid 60S with a light southerly breeze. A mid level shortwave (upper) trough will approach from the dakotas and bring increasing mid and high clouds to southern wi. Low levels (up to 15kft) will remain very dry through the night.

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Long Term

Issued 1154 PM CDT wed jul 29 2026

Friday through tuesday:

That upper trough will slowly track across eastern mn, wi, northern il, and mi/in from friday through saturday. There is only weak support of this trough in the jet stream level. At the surface, low pressure will track from the sd/NE border friday morning, through ia on friday, and across il fri nt into sat. The very slow movement of this system is due to the weak upper dynamics. The surface low also gets quite displaced from the mid level low during this time. Model profiles show the potential for weak and shallow instability at times, but nothing near strong/unstable. The chance for lightning is questionable for southern wi given these profiles.

While all of this suggests a very weak system for the upper midwest, the models are all producing high amounts of precip. I AM hesitant to buy into this idea given the lack of convection or strong synoptic forcing. The leading edge of the precip is expected to move into south central wi by mid friday morning and reach the lakeshore of southeast wi around mid afternoon. It will be encountering dry air, but we are expecting a solid period of a saturated column of air to affect all areas of southern wi between fri afternoon and saturday morning.

So confidence is increasing for a period of steady light rain, but i AM not expecting a drought-busting rain. Several ensembles have only a 35% chance of exceeding a half inch in 24 hr north of i-94, with higher confidence (up to 85%) south of there. This might be too generous based on the anticipated rainfall rates. There should be a pretty tight gradient of precip totals across southern wi by the end of this event, ranging from highest near the wi/il border and lowest toward east central wi.

The upper trough and resultant rain should clear south central wi by midday saturday and southeast wi by at least late afternoon. High pressure will spread back into southern wi on sunday and dominate through tuesday. A weak upper trough will try to bring some light rain or sprinkles to the state on tuesday afternoon/night, but that is looking weak and dry.

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Aviation

Issued 1154 PM CDT wed jul 29 2026

Clear skies tonight will give way to scattered diurnal cumulus clouds with bases around 5000 ft by mid morning. Winds will become southerly but remain light. Patchy fog is possible west of madison, especially in the wisconsin river valley tonight. While there is some light smoke in the upper levels (enough for an orange sunrise), it is not expected to reduce visibility at the surface. In the upper levels, we will see an improvement overnight and then a return later thursday afternoon. Expect increasing mid and high level clouds to spread into southern wi from the west starting thursday night. Steady, light rain is looking likely on friday.

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Marine

Issued 1154 PM CDT wed jul 29 2026

Light and variable winds will take on a southerly component by thursday afternoon as high pressure around 30.0 inches starts to drift toward the lower great lakes. Low pressure around 29.7 inches will track across iowa friday and through southern illinois by saturday morning. Breezy northeast winds will develop saturday and should continue through sunday afternoon as high pressure of 30.0 inches builds over lake superior.

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