June 18, 2021

New Podcast: The Truth about Record Temperatures and the Warm/Dry Weekend Forecast

There has been a lot of talk about heatwaves over the southwest U.S. this week, and I wanted to provide some heat-wave 101 in my new podcast (see below).

Have we been breaking more high-temperature records during the past decades?

The answer may surprise you! And I provide the weekend forecast, which promises dry conditions and temperatures increasing into the lower 80s during the next few days.

The origin of our warmth will be the development of a ridge of upper-level high pressure over the eastern Pacific during the next few days (see forecast map for Sunday morning).

Sunday Morning, 500-hPa Heights (around 18,000 ft)

You can listen to my podcast below or use your favorite streaming service.

You can also use your favorite streaming service (see below)


  1. This is a somewhat off topic comment. (Or maybe not.)

    Here in the US Northwest, most of the coal-fired power generation capacity that services our region, including the coal-fired power now imported from Montana and Wyoming, is scheduled to be retired before the end of the decade.

    The risks of the transition to wind and solar in our region are discussed in this article by Dr. James Conca, an energy policy expert who resides in Richland, WA:

    Washington State’s Approaching Energy Crisis – Good Intentions Gone Wrong?


    Here in Washington State, we have not yet forbidden the construction of new gas-fired power generation facilities. However, building new gas-fired capacity to replace the coal-fired capacity now scheduled to be retired is not in alignment with the Biden administration’s announced target of a 50% reduction in America’s greenhouse gas emissions by 2030.

    Let's be realistic. It is impossible to build enough wind, solar, and nuclear to replace the coal and gas-fired capacity which must be retired nationwide by 2030 in order to reach Biden’s 50% goal. The only way to reach that goal is through aggressive efforts targeted at energy conservation, even to the extent of imposing a government-enforced energy rationing scheme on the American people.

    Two big questions still remain to be answered:

    (1) How serious is the Biden administration about making substantial reductions in America’s greenhouse gas emissions? In other words, is Biden willing to use the full legal authority of the Executive Branch to its maximum possible effectiveness in forcing a quick reduction in our GHG emissions?

    (2) Will those who make the public policy decisions concerning how America's future electricity needs are to be supplied be inclined to force the shutdown of our legacy coal and gas-fired power resources, even if the retired capacity isn’t being fully replaced?

    1. A less reliable electrical grid and the possibility federally enforced energy rationing sounds pretty bleak. Hopefully the electrical utilities will get serious about innovating to avoid this future. In Dr. Mass's blog about melting ice cream he noted the incredible amount of energy released when water vapor condenses, latent heat of condensation. The Earth's atmosphere is full of water vapor just waiting for the opportunity of condense. Imagine a powerplant the runs on the latent heat of condensation! Maybe the need to find alternative methods to generate electricity will lead to such innovations, it's a bet I'm willing to take.

    2. Um, how do you propose to turn that water vapor into steam? Asking for a friend.

  2. Salt Lake City's tie for an all-time high temperature record might be a tad more significant when you take into account the previous record was set in late July, not the third week of June.

  3. Cliff:

    In contrast to the perspective you've shared in your podcast, this is a quite exceptional heat wave in terms of duration and intensity for this time of year in portions of the interior southwest.

    Salt Lake City's 107 might have only tied the all-time record, but it broke the record for June by 2˚F. The previous 107 was set in mid July. The average temperature in Salt Lake City for June 1-17 was 79.1˚F. This is 3.7˚F higher than the next warmest 1-17 June period. It is also warmer than 78% of the Julys back to 1875.

    Heat island effects contribute at KSLC, but Tooele, a small town in the valley west of Salt Lake City with records back to 1895, also broke its all time June record with 104˚F. It is worth noting that Tooele never recorded a June maximum temperature at or above 100˚F until 1988. Since then they have reached 100 or higher in 1988, 1990, 1994, 2001, 2002, 2008, 2008, 2015, and 2021. We are still more than a month from the climatologically hottest part of the year.

    Context is important. Yes, this occurred under a high-amplitude ridge. However, in some regions the temperatures really are exceptional and they are deepening severe drought and contributing to water scarcity. Clear linkages have been established in the literature between worsening drought over the southwest and global warming (see Udall and Overpeck 2017, Water Resources Research). Yeah, it's weather, but it's weather on steroids.


    1. Jim.... I will grant you that the SL City record is exceptional...but getting max records in the SW this time of the year in not unusual...in fact, quite typically. The reason you know...the inception of the monsoon clouds/precip in late June. As you also note, there is substantial urbanization around SL city that would tend to increase temps. A major heat wave no doubt, with a small portion of it due to GL. And yes, the last of precipitation during the past La Nina winter contributed...

    2. Your arguments are above are illogical. If you keep setting max records, what does that imply? Additionally, the climate of the northern Great Basin is considerably different than that of southern Arizona as the warmest time of year is generally in mid-to-late July. Focusing on Phoenix is a bit like saying a historic heat wave in northern California isn't impressive because Seattle didn't set any all-time records.

      As I mentioned, Tooele never observed a temperature in June over 100˚F until 1988. This June, they've hit 104 and had *3 days in a row* of 100 or more. The ridge argument caries little weight since the upper-level heights are intrinsically linked to the lower tropospheric temperatures.

      A better way to think about this is statistically. What were the odds temperatures like these in the northern Great Basin in early to mid June in the 20th century climate compared to today? Much lower.

      The fingerprints of global warming are all over this one as an amplifier of heat wave intensity and duration. Again, it's weather, but it's weather on steroids.


    3. Um, how does this compare to the 1930s? And how about the cold temp records, such as Germany just having concluded its coldest winter in 150 years? LOL

    4. Jim... I don't think there is any illogic here. Even if climate was perfectly stationary, we would still be breaking new records by random chance. Have you read Koonin's new book, Unsettled Science? John Christy did the extreme temperature analysis correctly and found there is no increasing trend for records. Take a close look at that section.... a real indictment of how some folks are doing such analyses...cliff

    5. There is a statistical reason why daily record highs would diminish over time, and it's quite simple. I'm surprised I never see it mentioned.

      Sea-Tac records began in 1949.

      In 1950, the odds were essentially 50% on any given day that a record high would occur, all things considered (at least tie the record).

      In 1999, the odds would be 2%.

      A much more accurate and meaningful metric would be to look at a sliding window of time, say 50 years, to see the trend of daily record extremes? So starting in 1999, see if any day was the highest (or tie) temperature for that day.

      And for all of 1999, how many do you get (i.e. highest daily temp from 1950-1999 inclusive)?

      Then for 2000, how many do you get (i.e. highest daily temp from 1951-2000).

      Up to 2020, how many daily highs in the period 1971-2020?

      I think this would be quite revealing, and the trend would be akin to the annual trends of the entire country of having the most energy in the atmosphere for the year (i.e. nth hottest year) metric.

      After all, in the year 2949, with 1000 years of daily records for any given date of the year, what is the likelihood of breaking a daily record? It's now competing with 1000 other days, versus just over 70 now.

    6. Two sources I trust -- Cliff and Bob Zybach, a forestry expert, both of them rigorous and fact-driven -- have noted that temps have NOT increased. In our region, average temps have actually declined a bit over the last several decades, while low temps have risen a bit.

      Jim, you and other Seattle "progressives" routinely make it up, and then imagine that no one noticed.


    7. Ben....such analysis is done the way you propose...and show that extreme records are not increasing in frequency...cliff

    8. Interesting. Depending some on the time framed the window, there’s not a lot of data. For a 50-year window, only 21 points.

    9. Thanks, that is interesting to know. I know that doesn't necessarily mean anything because it is just one place on the planet. But if you took 100 rural locations (to avoid city/pavement heat bubbles) and do that across the US somewhat geographically distributed, do you get the same result? It's probably just my imagination, but it seems that in the last couple of decades, cooler in the PNW has correlated to heat waves elsewhere in the US. But that might be derived from media emphasis, too.

    10. Koonin's book is called "Unsettled: What Climate Science Tells Us, What It Doesn’t, and Why It Matters". "Unsettled Science" is something else...

  4. Q re "record temps": I recall that questions were raised a few years ago about the location of the temperature sensor(s) (official thermometer) at SeaTac. While - yes - it's important for pilots to know what the air temperature is where they're taking-off and landing ---- how misleading may "airport temps" be given the proximity of pavement (tarmac and concrete), buildings, etc?

    Does the NWS have and use air temperature sensing equipment located in other places less intensely influenced by pavement, etc? (The data tables seem loaded with airport codes like SEA, BLI, etc)

    1. Those records exist. Go to the places (I think there are hundreds) where records have existed for a long time, and that aren't near metro areas, and in the U.S. average temps have dropped.

  5. What about low temperature records? When looking at temperature records on a local news site, it seems like the high temp record is almost always more recent then the record low. Is it naturally harder to set a record low here in NW WA? Or is it due to the overall temperature increase with time?


Please make sure your comments are civil. Name calling and personal attacks are not appropriate.

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