textproduct: Chicago

KEY MESSAGES

- Temperatures will remain generally above average through the upcoming 7 days.

DISCUSSION

Issued at 221 AM CST Thu Feb 12 2026

Through Friday Night:

A broad surface high continues to reside over the western Great Lakes and mid-Mississippi Valley this morning, but it will begin to meander eastward later today as a mid-level shortwave pivots out of the Dakotas. While it appears that most of the area will remain under the influence of the surface high and remain dry, there is an area of precipitation trying to organize across western IA with the aforementioned wave and mid-level f-gen circulation that is progged to get into west-central IL this afternoon. Recent hi-res (and globals) continue to show the better f-gen staying west of a Des Moines, IA to Bloomington, IL line which should keep any associated precipitation outside of our CWA. However, there is a small chance (~15%) that some sprinkles and/or light rain showers could ooze into our far southwest CWA this afternoon especially if the f-gen band establishes closer to Bloomington. For now have opted to maintain some 10-15% POPs along and west of a Peru to Paxton line locally to highlight this potential but suspect most will stay precipitation free today.

Otherwise, expect partly to mostly cloudy skies this afternoon as the disturbance swings by. Despite the cloud cover, temperatures are expected to once again warm into the low to mid 40s today as winds become more southeasterly this afternoon. However, those near the IL shore of Lake Michigan will likely stay in the mid-30s as a weak lake breeze moves inland this afternoon.

Heading into Friday, cloud cover will clear out as mid-level height rises move overhead. While this will allow temperatures to dip into the mid to upper 20s tonight, the combination of sunny skies and 10-15 mph southwest winds on Friday will rebound temperatures into the upper 40s to lower 50s areawide.

Yack

Saturday through Wednesday:

Operational ECMWF and a sizable portion of ensemble members remain farther north and bring rain into our southern CWA with the southern stream wave this weekend. NBM pops have trended up a bit, particularly near/south of the Hwy 24 corridor and saw no need for any adjustments.

Temperatures through the weekend into next week will remain above average, but the question will be just how far above average. Didn't make any adjustments to NBM temps through the period, but there are small nuanced details that could lead to some variability in temps each day. Saturday, thicker cloud cover and rain would likely result in cooler temps south of I-80. Lake breezes look like a good bet both days, likely keeping temps cooler near the lake.

Pretty good agreement in medium range guidance in a northern stream shortwave passing well north of the area Monday. This would result in a more solidified southerly flow and sets the stage for some very mild temperatures, even right up to the lakefront. Certainly a play for temps to be even milder than the NBM Monday, but there is enough ensemble spread to not make any changes at this distance.

Tuesday, a weak cold front trailing south from the aforementioned wave looks like it sags south into and through the area. This could result in temps MUCH cooler than the NBM, especially near the lake. By Wednesday, operational GFS and ECMWF eject a healthy shortwave out from the mean western trough and drag the front back north of the area. Low confidence this far out, but worth noting that there is quite a bit of ensemble support for highs well into the 60s, with ECMWF and probably a third of EPS members bringing 70s well into our CWA.

Depending on the strength of any potential lead wave ejecting out of the western trough, can't rule out some showers by late Tuesday into Wednesday.

- Izzi

AVIATION /18Z TAFS THROUGH 00Z SATURDAY/

Issued at 1116 AM CST Thu Feb 12 2026

VFR conditions are expected through the TAF period. Winds will be generally light and variable through tonight for most areas but will favor an easterly direction at the Chicago terminals this afternoon, still under 10 kt. Mid and high clouds will decrease in coverage from north to south later this afternoon into the early evening. Prevailing winds are expected to return to a south southwest direction Friday morning and increase to around 10-12 kt with occasional gusts into the upper teen to near 20 kt range possible early in the afternoon.

Petr

LOT WATCHES/WARNINGS/ADVISORIES

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