textproduct: Chicago

KEY MESSAGES

- Above average temperatures continue through mid week.

- Breezier winds expected Monday through Wednesday.

- Periodic precipitation chances expected mid week through next weekend.

DISCUSSION

Issued at 159 AM CST Sun Feb 15 2026

KLOT reflectivity is still showing returns along the Ford, Iroquois and Benton County lines this morning. However, the bulk of the precipitation is well to the south. That precip is expected to continue its track south and east of the forecast area. Rain chances drop off substantially in the next couple of hours and dry conditions are expected through the day today. There is a slight chance for patchy fog to develop around and south of US-24 where rain occurred, but with a light wind and plenty of cloud cover confidence is low and dense fog is not currently forecast.

Viewing nighttime microphysics imagery, there is a wide swath of high clouds draped over the forecast area. However, the back edge of these clouds is along a Moline to Kenosha line. As the system to the south that is driving the rain in central Illinois continues to move away from the area, cloud cover will decrease for the northern half of the forecast area through daybreak, and skies will then become sunny areawide during the day. Rockford is already on the edge of the back edge of the clouds and temperatures is already down in the mid 20s. While much of the Chicago Metro and areas south of I-80 will remain "warmer" in the 30s under the clouds this morning, forecasted minimum temperatures were lowered for rural areas north and west of the Fox Valley that will experience the most radiational cooling.

An upper level ridge will grow Sunday over the Plains and slide eastward on Monday. Temperatures are expected to increase back into the 50s. But with a warmer air mass moving in on Monday, there is a better chance for high temperatures to climb into the low 60s (upper 50s along the lake shoreline). However, with efficient deeper mixing expected in the afternoon, wind gusts around or over 25 mph will make for breezier conditions and may help limit how warm temperatures feel.

As an upper level trough moves eastward over southern Canada overnight Monday into Tuesday, a dry, backdoor cold front is expected to move southward toward northern Illinois. Breezier winds are expected once again with this front. However, there is a little uncertainty on how far south the cooler temperatures associated with this front will get. The best chances for high temperatures in the upper 50s (maybe isolated 60) should be along and south of Interstate 80. While much of northern Illinois is expected to still get into the low 50s, far northeastern Illinois will likely struggle to get out of the 40s, including most of the Illinois shoreline and the city of Chicago.

A longer wave upper level trough is expected to eject out of the the Rockies and move over the upper Midwest Tuesday night into Wednesday morning. Surface cyclogenesis is expected Tuesday night and most model guidance has the center of low pressure moving toward the Twin Cities and central Wisconsin. While that keeps the better forcing to the north, it remains close enough to allow for chances of rain for much of the area and even enough MUCAPE to merit the slight (less than 20 percent) chance of thunder with this system. Lastly, winds will once again be breezy with gusts 25 to 30 mph. While the better chances for rain are north of Interstate 80, as this system pulls away to the north and east, a drier air mass is expected to move in behind it, particularly for the rural, western portions of the forecast area. As gusts are expected to remain through Wednesday morning, there is a chance for increased fire weather concerns in areas that do not receive much rain as minimum relative humidity values drop during the day below 40 percent. Lower confidence on the high temperature forecasted for Wednesday, as it will depend on timing of the system exiting the area. Ensembles are still suggesting temperatures could climb back into the 60s. However, a cooler air mass moving in on Thursday behind this system is expected to return the area to more seasonable conditions.

Models are suggesting another system to arrive at the end of the week. But even compared to 24 hours ago, models are already suggesting a different amplitude and location of the next system. While confidence is lower with the details for what will arrive at the end of the week, with temperatures expected to gradually drop, the expectation is that it could start as rain before a return to a wintry mix leading into the weekend. Still a lot to be ironed out over the coming days.

DK

AVIATION /06Z TAFS THROUGH 12Z MONDAY/

Issued at 1107 PM CST Sat Feb 14 2026

Key Aviation Messages for the 06Z TAFs:

- Some patchy BR possible prior to sunrise at RFD/GYY.

- Low confidence in weak lake breeze late Sunday afternoon/early evening, mainly at MDW and GYY though can't rule out ORD.

Surface low pressure was over Arkansas late Saturday evening, and will continue to track east through Sunday morning with its associated area of rain and lower vis/cig conditions remaining well south of the terminals. North of the low, a weak and diffuse ridge of surface high pressure will linger across the terminals, and will support light (<5 kt) south-southwest winds overnight. Winds will eventually turn more westerly toward daybreak, and eventually west-northwest or northwest behind a surface low pressure trough which will pass midday. While these winds are only expected to be around 10 kts, model guidance continues to trend weaker with a lake breeze which looks to be confined to near the IL shore and into northwest IN late in the day/early evening. Have indicated a brief shift to northeast winds at GYY and MDW in the 23-00Z timeframe, with lower confidence of a sharper wind shift at ORD. It does appear however that winds will weaken and flop to south-southwest at all sites early-mid Sunday evening (including ORD).

Have started to see some light (6-7SM) BR developing at KRFD at issuance time, where high clouds have started to thin/scatter. There could be some brief MVFR vis there, though with winds eventually turning southwest and increasing slightly and a patch of VFR mid-level clouds expected to spread in from eastern IA predawn, am not currently expecting fog to become widespread or significantly denser. Surface dew points are also a bit higher at GYY, thus some MVFR BR can't be ruled out there prior to sunrise. Otherwise, VFR conditions are expected to prevail through the period.

Ratzer

LOT WATCHES/WARNINGS/ADVISORIES

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