textproduct: Chicago

KEY MESSAGES

- Temperatures trend warmer through the weekend and into early next week.

- Chances for periodic showers and storms will return to the area tonight into early Friday

- Scattered strong storm chances at times this weekend, though a good amount of dry time is likely.

- Better shot at more widespread showers and thunderstorms, some possibly severe, Monday into Tuesday.

DISCUSSION

Issued at 309 AM CDT Thu May 14 2026

Light winds and clear skies, under the influence of surface high pressure, have set up a chilly mid May morning across the area. Temperatures are expected to bottom out prior to daybreak in the upper 30s to the low 40s outside of Chicago. In spite of this chilly start to day, sunny skies and a moderating airmass will allow inland temperatures to rebound back well into the 60s to around 70. However, closer to the lake conditions will remain cooler for another day (temperatures in the upper 50s to around 60), as lake breeze influences result in onshore flow this afternoon.

Dry weather is expected through the day today. However, scattered rain shower chances will return to the forecast late tonight into early Friday morning as the first of several mid- level impulses ejecting out of the southwest CONUS begins to move into the central CONUS. Overall, the best rain chances (50%+) late tonight through early Friday morning will be across west central through east central IL. Farther north and east into the Chicago metro area, we are only looking at the possibility (20-30% chance) for a brief period of light showers. This activity should shift out of the area by mid-morning on Friday, with dry conditions forecast the remainder of the day. Even warmer conditions are anticipated Friday as breezy southerly winds (gusting 25-30 mph) set up during the afternoon. Accordingly, temperatures are expected to peak in the 70s, and the the offshore wind component will result in the warmth making it all the way to the Lake Michigan lakeshore.

The larger scale weather pattern will transition more quasi- zonal (west-to-east flow) for a period to start the weekend, before the next upper trough digs into the western CONUS later in the weekend, fostering a shift to southwest upper-level flow early next week. The net result of this will be return to periods of active weather (showers and thunderstorms) this weekend through early next week. While this is the case, it will not be storming constantly across our area. In fact, we are likely to experience a lot of dry time this weekend, so it will not be a wash-out by any means. Shower and storm chances will begin to return to the forecast Friday night into Saturday morning, as thunderstorms developing west of our area in association with an approaching mid-level disturbance later Friday attempt to shift towards our area later Friday night. At this time, the severe threat in our area with this activity through early Saturday morning is low, owing to the poor diurnal timing.

More scattered thunderstorms will be possible Saturday afternoon as a surface frontal boundary sags into the area. However, it is possible that the primarily focus for these end up across the southern half or so of the area following any early morning activity pushing the effective surface boundary farther south. If this ends up being the case, capping and little focus for renewed development farther north could result in a mainly precipitation free afternoon across much of far northern IL. Later in the weekend into early next week, an upper-level trough will dig across the western CONUS, fostering continued periods of active weather from the Plains and Midwest through the western Great Lakes region. Several waves of showers and thunderstorms will be favored in this pattern, particularly west and northwest of the area (on Sunday) as Gulf moisture surges northward in advance of an elongated region of surface low pressure extending from the central Plains northeastward into the upper Midwest. Locally, shower and thunderstorm chances will continue Sunday into early next week, but our best shot at a higher areal coverage of showers and thunderstorms (some potentially severe with instances of heavy rainfall) looks to come Monday into Tuesday in association with an approaching surface cold frontal passage. Confidence on the timing of this front shifting into our area remains low, owing to large ensemble spread.

KJB

AVIATION /12Z TAFS THROUGH 18Z FRIDAY/

Issued at 627 AM CDT Thu May 14 2026

High pressure currently over northern Illinois will shift east today, allowing WNW/NW winds under 10 knots to gradually favor NE by late morning. A lake breeze will then shift winds E around 10 knots early in the afternoon for ORD/MDW. At RFD, winds will remain generally S this afternoon. For all terminals, expect winds under 10 knots to settle SE by late evening, then veer SSE to SSW while beginning to gust over 20 knots around and shortly after sunrise Friday. Winds will remain SSW with gusts up to around 25 knots mid morning into the afternoon.

VFR conditions are expected through the period. Decaying mid- level SHRA may cross or pass just south of the terminals around sunrise Friday.

Kluber

LOT WATCHES/WARNINGS/ADVISORIES

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