As is common around here this time of year, we are quickly moving from the month of May diatribe of “When are we going to get some summer weather?” to “Holy Cow! It’s way too hot out there!” As a strong hot ridge of high pressure builds into the Great Basin, high temperatures should move into the low 90s Wednesday and approach triple digits by the weekend. Records are likely to fall by the time we get into the weekend. The airmass is stable enough so that the skies should stay mostly clear through Saturday, but by Sunday all that heat could bring the possibility of afternoon thunderstorms.

With all this heat, folks wonder if evaporative (swamp) coolers can do the job. There are lots of areas across the country that get pretty hot where you would never find a swamp cooler. That’s because you also need low humidity in order for the physics to work out. A swamp cooler works because of the heat of vaporization. In order for liquid water to evaporate, it needs to take in energy to break the intermolecular attractions between water molecules. So liquid water absorbs heat from the air as it evaporates, cooling the air. A simple design allows swamp coolers to take advantage of this. I’ll have more tomorrow.