A tire pressure alert, that is ... I checked the tires and found that I had about 28 psi in each.
This seemed too high to generate the alert, but at the same time I knew that recommended pressure for this car is 36 psi.
An extended family member had swiped my little compressor out of the garage and burned it up by overuse, so I ordered a new one:
It's an improvement over the previous (Kensun) inflator in that (1) it's a little bit quieter (still loud, though) and (2) it allows you to program the desired pressure level in and automatically inflates the tire to that level.
I blew all 4 tires up to 36 psi last night, and this morning received the pleasant surprise:
No more warning light, and 70 miles available instead of the 61 I'd seen yesterday (similarly cold foggy weather). I gather that the computer calculates available miles based on several factors including air temperature ... and tire pressure!
Anyway, keeping my tires at 36 should make me a little less dependent on the superchargers around the area ...