For much of July, temperatures have been tolerable, but the high yesterday was 98ºF and the overnight minimum through 6 am only 77ºF. However, when the wind at the airport shifts to northwesterly from 7 to 8 am, as was the case this morning, you know some cool goodness must be on the way.
Bonafide midlatitude troughs can be rare sightings in Utah in July, but one is moving in as we speak. The NW wind shift at the airport this morning marks the leading edge of cooler air at the surface accompanying and upper-level trough that was centered over Nevada at 6 AM MDT (1200 UTC) this morning.
With yesterday's blistering heat, our 700-mb temperature was around 16ºC, but the air accompanying the upper-level trough this morning is several degrees cooler.
By this afternoon, our 700-mb temperature will be about 6ºC, about 10ºC (18ºF) lower than yesterday afternoon.
Right now, believe it or not, it's 66ºF with a 45 knot wind along I-80 on the Salt Flats. That cold air is on the way. Temperatures this afternoon will be in the 70s. Strangely enough, the max for the calendar day (midnight to midnight) will end up being 85ºF because that's what it was shortly after midnight.