textproduct: Chicago

KEY MESSAGES

- A warming trend during the early part of next week with 60s Sunday and 70s Monday and Tuesday. - Elevated fire weather conditions for the rest of today and possibly again on Sunday. - Stormy weather pattern returns towards the middle of next week.

DISCUSSION

Issued at 145 PM CDT Sat Mar 28 2026

Through Sunday...

It's a quiet and seasonably cool Saturday afternoon out there. The surface high centered over northern IL this morning has since scooted off to the east allowing for SW winds to gust to 15 to 20 mph this afternoon while keeping the sunny skies around. The southerly flow has also allowed afternoon dewpoints to stay a bit higher than some of the drier model solutions were suggesting. So while there certainly remains an elevated risk for fire spread through this afternoon, conditions haven't quite warranted issuing any formal products for this.

The base of the upper trough is still working its way out of the region. After it moves away later tonight, steady upper height rises will promote deep warm advection into tomorrow. Afternoon temperatures are forecast in the lower 60s beneath partly cloudy skies. Tomorrow will be another day with SW gusts to around 20 mph at times. Dewpoints getting up into the 30s will lessen the fire weather risk some compared to today, but at least a marginally elevated fire risk is anticipated tomorrow. No rain is expected through the remainder of the weekend.

Monday through Saturday...

Attention then turns to the Monday night through Tuesday timeframe for our next chance for thunderstorms. A stout shortwave will trek along the US-Canadian border early next week and phase with another wave ejecting out of the central Plains. This will result in a quickly deepening surface low across the upper Midwest with its cold front expected to move through the area on Tuesday. Out ahead of the wave, strong low level warm advection will overspread the region allowing for an unseasonably warm day on Monday with highs forecast in the 70s to near 80 degrees, warmest west and southwest of the Chicago metro. The southern stream wave will drive a baroclinic zone northward into the upper Midwest during the day and advect deep layer Gulf moisture into the region, including surface dewpoints into the 50s. This baroclinic zone will act as the system's warm front and should stall up to our north across Wisconsin for Monday night. Atop the anomalously warm low levels, midlevel lapse rates will be pushing 10K/km during the latter part of Monday. Some model camps suggest we could see isolated instances of elevated convection Monday night in the storm's open warm sector. However, while there will be some transient dynamic forcing ahead of the wave, an overall lack of forcing in a heavily capped environment should make it difficult to realize this instability aloft and see much in the way of precip development, if any. Better convective chances Monday night exist north up into Wisconsin nearer to the surface front. This thinking lines up well with the current SPC Day 3 outlook which paints a marginal risk along and north of the IL-WI state line. If a few storms were to get going in our local area, would need to watch for the possibility of small hail given those lapse rates.

A greater chance for thunderstorms will arrive on Tuesday with the passage of the storm's cold front. Guidance as a whole has been trending earlier with the timing of the frontal passage, but there are still noteworthy disagreements. The deterministic Euro and its ensemble counterpart are the earliest calling for a late morning through afternoon frontal passage. Other global camps and the few regional camps that now look out into Tuesday favor an afternoon into evening passage. The low levels still look plenty capped ahead of the front through the morning and even into the early afternoon, so an earlier solution could mean overall less thunder coverage in our area, especially with westward extent. In fact, most guidance now has the convective line along the front forming or intensifying basically right overhead. Once storms do mature along the boundary, parameter spacing appears somewhat marginal for severe convection, but seemingly ample to support strong thunderstorm winds and perhaps some hail. Will continue to closely watch forecast trends with this front and should have a better outlook soon as more guidance becomes available. Daytime temperatures will also be influenced by the timing of the cold front, but we are favored to again see 70s to near 80 on Tuesday.

Expect cooler conditions for the middle of next week in the wake of the front. Highs in the 40s are forecast around the area on both Wednesday and Thursday. The baroclinic zone will get hung up over the lower Midwest on Wednesday with some additional precip tracking along. Some guidance suggests precip coverage may extend far enough north to fall on parts of our CWA, but the more likely solution is that we stay dry on Wednesday. Better precip chances arrive on Thursday along the northern flank of another surface low slated to track across south-central IL. Temperatures look to return to the warmer side of normal for the end of the week as another large synoptic system gears up to move across the region over the weekend.

Doom

AVIATION /00Z TAFS THROUGH 06Z MONDAY/

Issued at 632 PM CDT Sat Mar 28 2026

Key Aviation Messages for the current TAF period:

- Gusty southwest winds around 20 knots tomorrow afternoon

Increasing high cloud cover through the overnight, but VFR conditions are expected through the TAF package. This afternoon's southwest wind gusts around 20 knots will gradually diminish after sunset. Winds will remain southwest through the TAF period. Lighter winds 5 to 10 knots through the overnight, before gusts around 20 knots kick up again around noon tomorrow.

There is a marginal chance for low level wind shear (LLWS) over KRFD tonight, but should dissipate by sunrise. Another low level jet is expected to ramp up after sunset tomorrow. Any threat of LLWS would be more focused over northwest Indiana, but confidence remained too low (for a threat late in the forecast period) for any mention in the current TAFs.

DK

LOT WATCHES/WARNINGS/ADVISORIES

IL...None. IN...None. LM...None.