textproduct: Chicago

KEY MESSAGES

- Near to above normal temperatures with predominantly dry conditions are expected through much of this week.

DISCUSSION

Issued at 318 PM CDT Mon Oct 5 2026

Dry conditions are expected to persist into tomorrow as a sprawling ~1025 mb surface high continues to exert its influence across the region. The surface pressure gradient will tighten as the center of this surface high repositions itself to our east and a ~996 mb surface low tracks from northern Manitoba into northern Ontario with an associated cold front pressing southeastward towards the Great Lakes. This will yield breezy southwesterly flow here tomorrow -- primarily across the northern half of our forecast area, where some gusts into the 25-30 mph range are likely during the afternoon. The same dry air mass that has allowed for air temperatures to overperform most raw model guidance today will remain in place for tomorrow, suggesting that a similar theme of overperforming temperatures will be followed for yet another day. Accordingly, our gridded forecast for tomorrow contains high temperatures in the low-mid 70s that fall in the upper echelon of available forecast guidance.

The aforementioned cold front will track across our forecast area early Wednesday, though it won't really seem like much of a cold frontal passage as relatively deep post-frontal mixing into drier air aloft should largely offset the modest post- frontal cold air advection. When coupled with mostly clear skies, high temperatures on Wednesday actually look like they will be slightly warmer then Tuesday's highs and could even reach the low 80s across our southern CWA, in spite of the frontal passage. Cooler high temperatures in the mid 60s to mid 70s are ultimately expected on Thursday as modest northwesterly to northerly winds persist and the heart of the cooler air mass settles into the region. Similar temperature readings are then favored again on Friday before strengthening south to southwesterly low-level flow helps facilitate another warm-up into this weekend.

With a dearth of moisture accompanying Wednesday's frontal passage and surface high pressure settling back into the region thereafter, no precipitation is expected on Wednesday or Thursday. There remains a signal in ensemble guidance for some combination of a low-amplitude shortwave, isentropic ascent, weak frontogenesis, and somewhat steepened mid-level lapse rates to come together and induce a wave of showers or sprinkles somewhere in the region sometime in the Thursday night into Friday time frame. However, there isn't much spatiotemporal consistency with this at this time, and even if things were to come together just right to support precipitation in our forecast area during this time frame, the persisting parched low-mid-level air mass would likely play some role in limiting the amount and/or the spatial footprint of any measurable precipitation.

Ensemble guidance then supports precipitation-free conditions across our area on Saturday and mostly favors those conditions continuing into Sunday at this time. Will note that there is some potential for deeper moisture associated with a tropical disturbance currently over the Bay of Campeche to be approaching our latitude come Sunday, though there is still a high degree of uncertainty at this point with how that tropical disturbance will evolve and whether its associated moisture will eventually be advected in the general direction of the Great Lakes or be pulled more northeastward towards the Mid-Atlantic.

Ogorek

AVIATION /00Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 620 PM CDT Mon Oct 5 2026

No major forecast concerns are expected for this TAF period as high pressure will continue to reside over the Great Lakes and Midwest. Therefore, expect mostly clear VFR skies to prevail. Winds will gradually become southeasterly this evening with speeds around 5-7 kts tonight before turning southwesterly by mid-morning on Tuesday. Speeds are expected to increase Tuesday afternoon with gusts peaking around 20-25 kts, though gusts should diminish after sunset Tuesday evening leaving west- southwest winds around 8-10 kts for the remainder of the forecast period.

Yack

LOT WATCHES/WARNINGS/ADVISORIES

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