Tuesday forecast: Sunshine and warmer temps but a cooldown is coming

Chicagoans can finally look forward to a brief break from the recent stretch of cooler weather.

Tuesday will bring plenty of sunshine and warmer temperatures, with highs reaching 80 degrees for the first time in 10 days. It’s likely to be the warmest day of at least the first half of September.

But don’t get too comfortable — a cooldown is just on the horizon.

Clouds are projected to increase on Wednesday, with highs in the mid- to upper 70s.

Showers and thunderstorms are also possible later in the day Wednesday as a cold front moves across Chicagoland. That will usher in significantly cooler air for the end of the upcoming work week, with highs only in the mid-60s.

6-10-day forecast: Sept. 4-8

A strong cool signal is on tap, with much below normal temperatures locked into place across the Midwest and Great Lakes:

Forecast 850-millibar temperature animation: 1 mile above surface

This is a good proxy indicator of how temperatures will respond at the surface. The blue represents cooler than normal and the darker shading indicates an even larger deficit relative to normal:

You can see the magnitude of the cool air that arrives later next week into the following weekend. This will result in temperatures more typical of mid-October than early September.

The unseasonably chilly air arrives late this week.

Thursday highs

Thursday high: Departure from normal

Friday highs

Friday high: Departure from normal