textproduct: Chicago

KEY MESSAGES

- Milder temperatures are expected for much of the upcoming work week.

DISCUSSION

Issued at 126 AM CST Mon Feb 9 2026

A persistent stratus layer with bases around 5-7 kft should gradually shift northeast and slowly erode through this morning as the cloud-bearing flow turns southwesterly with time. Satellite imagery indicates we'll continue to pick up additional high-level cloud cover this morning and afternoon, but precip- free conditions are expected. Warm advection will intensify a bit this afternoon which should allow temperatures to push into the 40s across the southwest quadrant of the CWA, even amidst tempered insolation with the incoming cirrus cloud cover.

This evening/overnight, a modest 1005 mb surface low is forecast to slide across southern Wisconsin. Ahead of the low, an impressive LLJ is forecast to ramp up through the night, with guidance resolving 55-60 kt flow around 900 mb. Near-surface stability will limit much of this momentum from transferring to the ground, but some intermittent gusts around 20-25 kts will be possible at times. Eventually, a cold front will sweep across the area through early Tuesday morning. Aside from the typically too-moist NAM/NAMNest, not seeing a strong signal for drizzle as the low pivots into lower Michigan and have resultantly maintained a dry forecast.

In the wake of the morning frontal passage, fairly stout pressure rises (5-6 mb/3 hrs) combined with steepening low-level lapse rates should facilitate the development of gusty WNW/NW winds through Tuesday morning into the afternoon. NBM winds look underdone in the post-frontal airmass on Tuesday, and suspect some boosting will be necessary with guidance supporting a period of 30 mph gusts post FROPA. Even with low-level CAA continuing into the afternoon, high temperatures look like they'll manage to to push into the low 40s across most of the region, and even into the mid/upper 40s south of I-80.

The next disturbance is slated to march across the region on Thursday. Ephemeral/disorganized mid-level frontogenesis is forecast to develop through Thursday morning as 700-600 mb confluence increases as an associated shortwave shifts out of the Dakotas. Forecast soundings reveal a decent amount of antecedent dry air below 700 mb as east to southeast low-level flow develops, so there's some uncertainty regarding whether precipitation (snow) will be able to break through. NBM PoPs on Thursday-Thursday night have been pretty steady in the 20-30 percent range and this still looks representative at this point with relatively better chances for snow to our west.

On Friday, a southern stream wave appears likely to move across Baja California into Sonora, Mexico and eventually through the ArkLaTex on Saturday. Whether or not this wave loosely phases with a series of northern stream disturbances remains a bit unclear, but these features collectively may bring some potential for precip back into parts of the region late in the weekend.

Carlaw

AVIATION /18Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 1109 AM CST Mon Feb 9 2026

A vigorous clipper system will race through the Great Lakes during the TAF period. With a lack of low-level moisture, the primary impact of the system will be expressed via winds.

To start, surface winds will prevail out of the south to southwest direction (180 to 200 deg) through the afternoon hours. Toward sunset, wind directions may respond to surface decoupling by turning toward the southeast (160 to 180 deg), before turning back southwesterly by midnight. A stout southwesterly low-level jet (45-50kt at 2kft) will develop overhead through the overnight hours, leading to LLWS. After daybreak, a cold front will move across the airspace causing surface winds to turn northwest (310 deg or so). Efficient mixing should support prevailing gusts in the 25-30 kt range with occasional gusts up to 35 kt.

Borchardt

LOT WATCHES/WARNINGS/ADVISORIES

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