I arrived yesterday evening at the Salt Lake City airport to an apocalyptic scene. What the hell did you do to Utah while I was gone? Where are the green Avenues foothills? The patches of high mountain snow? I haven't been gone all that long, but the transformation is dramatic.
Much has gone on in the past week or two. We've already spoken quite a bit about the June heat, but how about the air quality? In Utah, we tend to think about wintertime inversions, but during the summer, our ozone can also become elevated. Below is a time series of ozone levels on the University of Utah campus over the past 30 days. Ozone is produced photochemically by the sun's ultraviolet radiation and shows a pronounced diurnal signal with a maximum in the late afternoon and a minimum overnight, as is clearly evident below. However, you can also see how the peaks were highest during late June during the height of the heat wave.
The Weather Channel has a good summary of the weather records here. 98.1ºF at London's Heathrow Airport, which looks to be a July record for the UK (the all-time record is 101.3ºF set in Faversham (Kent) on 10 August 2003). 103.5ºF in Paris (2nd highest all time). 103.5ºF in Madrid (June record). These are brutal temperatures, especially in northern France and the UK.