Uncharted Meteorological Territory and the Evolving Hot Drought

 Don't let today's cool weather fool you, this June has been and will continue to be a disaster meteorologically, further exacerbating extreme to exceptional drought and fire weather conditions across the State of Utah.

In the previous post, we discussed the remarkable heat of the first 6 days of June.  Here's an update.  The average temperature at the Salt Lake City International Airport for the first 9 days of the month was an incredible 79.8˚F.  This is the warmest start to any June on record.

Source: http://xmacis.rcc-acis.org/

Let's take a closer look at the graph above.  Until 2016, the highest average June 1-9 temperature was 73.6˚F (1977).  We were 6.2˚F warmer than that!  In Salt Lake City, the urban heat island may be a local contributor, but even Alta had an average June 1-9 temperature of 59.3˚F, which is its highest on record.  Ah but the records there are spottier and only go back to the early 1970s.  How about we look at Tooele.  Records back to 1896.  Even there, June 1-9 has never been hotter.  

Source: http://xmacis.rcc-acis.org/

We are in uncharted meteorological territory.  

Today's cold frontal passage will bring pleasant temperatures to northern Utah, but this is a brief respite.  The computer model forecasts call for us to return quickly to exceptional warmth.  For example, look at the GFS forecast below for 0000 UTC 14 June (6 PM Sunday).  Deep trough off the west coast, high amplitude ridge over the upper plains, and Utah in the intermediate hot, dry southwesterly flow.  

The NWS forecast is as ugly as it gets.  One day of cool weather today.  By Friday, we're already back to a near average 81˚F.  After that, 92, 98, 100, 101, 99....

Source: NWS.  Downloaded 8 am MDT 10 June 2021.

This is the epitome of "hot drought" in which aridity is exacerbated by high temperatures, which increases evaporation and transpiration and the demand for water for irrigation.  It is estimated that approximately 1/3 of the decline in Colorado River runoff in recent years is due to higher temperatures.  

This has been anticipated for some time.  The Blue Ribbon Advisory Council on Climate Change Report to Governor Jon Huntsman, Jr. published on October 3, 2007 (available here) includes a chapter prepared by several Utah climate scientists including myself.  Amongst our conclusions:

•  "Utah is projected to warm more than the average for the entire globe and the expected consequences of this warming are fewer frost days, longer growing seasons, and more heat waves."

• "Ongoing greenhouse gas emissions at or above current levels will likely result in a decline in Utah's mountain snowpack and the threat of severe and prolonged episodic drought in Utah is real."

For city residents, the effects of drought are not always readily apparent, but they are severe and costly.  The National Integrated Drought Information System estimates that since 1980, 26 major national droughts have cost the U.S. at least $249 billion.  Amongst natural disasters, only hurricanes have caused more damage in that period (see https://www.drought.gov/news/high-cost-drought).  

This drought is not an act of God.  It is a reflection of weather and climate variability supercharged by anthropogenic climate change.  The climate of the 20th century is over.  This is a new world of change.