textproduct: Chicago

KEY MESSAGES

- Temperatures will remain generally above average through the upcoming 7 days, particularly into early next week.

DISCUSSION

Issued at 150 AM CST Tue Feb 10 2026

A cold front will move across the area later this morning, though the air mass behind the front is of Pacific origin, so the cool down will be pretty modest. Front will be moisture starved, so only noticeable impact to our weather will be the gusty northwest winds that develop later this morning into this afternoon in the wake of the front.

One time period of interest worth watching for some precip chances is Thursday. In response to a pair of approaching northern stream shortwave troughs and southern stream ridging attempting to build eastward, look for a substantial tightening of mid-upper level geopotential heights from the Cornbelt southeast into the Ohio Valley Wednesday night into Thursday morning. The result will be a quickly developing, strong mid- upper level jet streak, potentially nearing 170kt at 250mb Thursday morning. Significant ageostrophic response to this rapidly developing jet streak plus an approaching shortwave should lead to the development of a strong/deep f-gen circulation Wednesday night over the Cornbelt. There should be a gradual relaxing of the ageostrophic flow Thursday as the jet streak begins to weaken Thursday afternoon.

Vertical cross sections through the f-gen circulation show considerable negative saturated EPV co-located with the warm (ascending) side of f-gen driven vertical circulation, particularly Wednesday night into early Thursday morning. It is quite common for guidance to depict too rapid weakening of well developed f-gen bands and I am concerned that could be the case with Thursday as well. Chances of 0.01" of QPF from the EPS are notably higher than NBM PoPs, upwards of 70-80% over our western and southwestern CWA Thursday. Frontogenetically driven precip bands can be particularly difficult to predict this far in advance, between issues with placement and dealing with a likely sharp cut off to precip to the north of the f-gen, opted to not adjust NBM pops upward yet, but this will be a period to watch. Temps generally look to be above freezing, so barring any dynamic cooling, the chances for accumulating snow don't look too high, in fact precip could be rain/snow mix even.

By Friday and into the weekend, a southern stream shortwave is likely to track safely south of our area. The 00z GEFS and EPS suite have continued to trend farther south, but the time-lagged nature of the NBM keeps rain chances going through the weekend. Assuming no unforeseen northward shifts in guidance, it looks like the weekend should be dry with relatively mild temperatures. Guidance has been exhibiting a bit of a cool bias, so temps could be even milder than the current NBM advertised mid-upper 40s, especially if cloud cover is less extensive. Though the system passing to our south should result in winds off the lake, so temps near the lake will be colder this weekend (a sure sign that spring isn't far away).

GEFS and EPS both suggest there'll be further amplification of upper ridging over the central and eastern U.S. heading into early next week. Still details to be ironed out regarding any shortwave troughs breaking off the western ridge and throwing a wrench in temps, but potential is looking good for temps to warm into the 50s early next week, possibly well into the 50s.

- Izzi

AVIATION /06Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 1045 PM CST Mon Feb 9 2026

Key Messages:

- LLWS through early Tuesday morning.

- South-southwesterly winds turn northwest around daybreak, then turn gusty by midday.

VFR conditions are anticipated through the TAF period, with only some higher level CIGs and some scattered lower clouds expected. While south-southwest wind speeds will remain in check (10-15 kt) overnight, southwest winds will increase up to 50 kt a couple thousand feet off the surface overnight. Accordingly, LLWS is expected for several hours tonight before things improve towards daybreak. Otherwise, expect a cold front to sweep across the area around, or just after, daybreak Tuesday morning. In its wake, surface winds will turn northwesterly, with gustiness increasing (~25 kt) later in the morning and afternoon before abating some with sunset Tuesday evening.

KJB

LOT WATCHES/WARNINGS/ADVISORIES

IL...None. IN...None. LM...Small Craft Advisory from 8 AM this morning to 6 PM CST this evening for Winthrop Harbor IL to Gary IN.