textproduct: Chicago

KEY MESSAGES

- Above average temperatures through Thursday, with record warmth likely today.

- Scattered showers and a low chance (20%) of thunderstorms early Wednesday morning.

- Elevated fire danger Wednesday with westerly winds gusting to 30-40 mph.

- Additional rain chances Thursday night/Friday morning and possible rain/snow chances Friday night/Saturday.

DISCUSSION

Issued at 317 AM CST Mon Feb 16 2026

In the near term, early this morning, we continue to monitor fog trends across central IL into IN. However, as of this writing, the web cams and surface observations across my south do not currently support the need for a Dense Fog Advisory. This may change over the the next few hours as lower-level moisture continues to ease northward from central IL into portions of east central IL and northwestern IN. The main uncertainty at this point is how widespread any dense fog may become into my southern areas early this morning, owing to increasing low-level southwesterly flow toward daybreak and the presence of higher level cloud cover streaming over the region. For this reason, we will continue to monitor observational trends early this morning before locking into a Dense Fog Advisory.

A breezy day is expected today as diurnal mixing into the increasing southwesterly low-level flow will support numerous gusts of 25 to 30 mph through the afternoon. While cloud cover will linger over the area this morning, we should see more sunshine this afternoon, which should allow temperatures to become unseasonably warm, into the low to mid 60s. This is expected to break the record high temperature for today (the 16th) at both Chicago and Rockford, which currently stand at 58 and 57 degrees (both set in 1921), respectively.

A weak cold frontal boundary is expected to sag southward into far northern IL and northwestern IN this evening, before stalling near the I-80 corridor tonight into Tuesday. East- southeasterly winds setting up near and north of this frontal boundary for Tuesday will result in much cooler temperatures (low to mid 40s) near the northeastern IL Lake Michigan lakeshore on Tuesday. Conversely, interior sections of northern IL and northwestern IN should again experience temperatures topping out well into the 50s to around 60.

The weather will turn a bit more active for the remainder of the week as two notable low pressure weather systems take aim on the region. The first of these will track eastward from the northern Plains out across the upper Midwest Tuesday night into Wednesday as a weakening northwest-to-southeast oriented area of low pressure. This will result in our next chance of showers (and perhaps an isolated thunderstorm) Tuesday night. There does continue to be some uncertainty in the coverage of showers with this system Tuesday night. In spite of this, there is a short period overnight in which the exit region of a 140 kt upper level jet streak will nose into northeastern IL. Dynamically, this is favorable for the short period of likely (60%+ chance) POPs going in the current forecast late Tuesday night. Steepening mid-level lapse rates also could support a few elevated late night storms.

Conditions will dry out considerably and become windy during the day Wednesday following an eastward surging frontal boundary. Dewpoints in the wake of this boundary are likely to fall into the 20s to the low 30s as surface temperatures efficiently warm into the mid 60s during peak afternoon mixing. This adds increasing fire weather concerns for Wednesday, owing to minimum RH percentage values likely falling into 20s amidst gusty westerly winds of 30-40 mph.

Ensemble guidance continues to support another storm system tracking eastward across the central part of the country somewhere into our region late Thursday into Friday. There remains quite a bit of uncertainty with this system, owing to large ensemble spread at this time range. Nevertheless, chances continue to increase in our next period of showers, and maybe a period of isolated thunderstorms, Thursday night into early Friday. Blended pops are now into the 60-70 percent range and that seems reasonable from this distance.

Beyond this time period, the overall trend looks colder with perhaps below normal temps by early next week. The transition to this colder pattern will also support some possibly of snow in the region.

KJB

AVIATION /18Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 1133 AM CST Mon Feb 16 2026

Southwest winds will gust 25-30kt through daylight hours amidst an unseasonably warm and spring-like day. A few high clouds will stream overhead during daylight hours.

Tonight, a weak frontal boundary will slip southward through the Lower Great Lakes and stall somewhere in the vicinity of RFD/DPA/ORD/MDW. Winds near/behind the front will become nearly variable, though perhaps favor a modestly east-southeasterly direction. With the low-level pressure gradient relaxing locally overnight, do believe pockets of fog may develop particularly toward daybreak near and especially behind the front, especially if flow is modestly stronger than currently expected and advects relatively moist air inland off Lake Michigan. Then again, the low-level flow may be just strong enough to favor a low-level stratus deck instead of fog. All things considered, will go ahead and maintain 6SM BR SCT003 at MDW/ORD/DPA, and introduce a TEMPO at RFD for 1SM BKN002 at RFD, altogether centered during the pre-dawn hours of Tuesday.

Low-level flow will pick up out of the south-southeast mid- Tuesday morning and erode any lingering stratus and/or fog. Upper-level clouds will then thicken in advance of an approaching storm system.

Borchardt

CLIMATE

Issued at 913 PM CST Sun Feb 15 2026

Record warmth is forecast on Monday February 16th, with highs into the 60s.

Here are the current record highs for February 15th for Chicago and Rockford:

Chicago: 58 degrees in 1921 Rockford: 57 degrees in 1921

NWS Chicago

LOT WATCHES/WARNINGS/ADVISORIES

IL...None. IN...None. LM...Small Craft Advisory until 6 PM CST this evening for the IL and IN nearshore waters.