Early Summer Heat

The National Weather Service has issued an Excessive Heat Warning for the northern Wasatch Front, Salt Lake Valley, Utah Valley, and the Great SaltLake desert for noon Friday to 6 AM Saturday.  Below is the warning issued this (Thursday) morning at 3:24 AM.

Below is the infographic from their page showing comparisons of forecast and record highs for today (Thursday) and tomorrow (Friday).  If we hit 100 tomorrow, it would be the earliest on record by a day.  

When it comes to susceptibility to heat, there's a lot more going on than just temperatures.  All else being equal, early season heat tends to affect people more severely.  Overnight temperatures matter for individuals without access to air conditioning.  Exposure to the sun can be critical, and with a strong ridge in place and the summer solstice near, we will see near-maximum possible ultraviolet radiation intensity.  

For some long-term context, below is a graph showing the dates of the first and last 100˚F day each summer in Salt Lake City since 1895.  Except for a brief period during the 1930s, days of 100 or more were relatively uncommon.  They have become more common since 1960.  On or before June 25, 100 or more has occurred only 20 times and on or before June 11 only 5 times.  

Source: http://xmacis.rcc-acis.org/

Expect more of this in the future.  Sadly.