Environment & Energy

hatrack

(60,951 posts) Mon Jul 1, 2024, 07:46 AM Jul 2024

California Central Valley, Death Valley May See New Temperature Records Week Of 1 July

Heat will build over parts of California this week, potentially challenging current temperature records. The US National Weather Service has issued excessive heat warnings and heat advisories for the days between Tuesday and Saturday due to “dangerously hot conditions” with temperatures likely to soar into the triple digits fahrenheit.

Temperatures have already been building across the Sacramento and San Joaquin valleys this past weekend, but will continue to rise through this week. One of the hottest cities will likely be Fresno, where maximum temperatures could exceed 110F (43C) across multiple days.

Death Valley may also get close to 130F (54C) towards the end of the week; a temperature that has been reached only three times – in 1913, 2020 and 2021. Temperatures more widely will reach 100-110F (38-43C) between Tuesday and Saturday, although peak temperatures could reach 115F (46C), which would be 5-10C above the climatological average. In addition to the high daytime maximum temperatures, there won’t be much relief overnight, with minimum temperatures dropping into the mid-60s F to low-80s F (around 18C-28C).

Alongside scorching temperatures, officials are warning this week of elevated fire conditions, particularly the first half of this week with strong winds and low humidity expected. Fires have already been reported this past weekend, as firefighters battled a 250-acre brush fire in Riverside County on Saturday. With the Fourth of July federal holiday this week, Cal Fire officials are reminding residents to be safe when lighting fireworks because of their propensity to spark fires.

EDIT

https://www.theguardian.com/environment/article/2024/jul/01/scorching-temperatures-across-us-threaten-heat-records

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California Central Valley, Death Valley May See New Temperature Records Week Of 1 July (Original Post) hatrack Jul 2024 OP

Ough.......................... Lovie777 Jul 2024 #1

Fresno is predicted to be 116F next weekend. That's Death Valley weather in my book. usonian Jul 2024 #2

A small little change in average temperatures dramatically increases the number of days with extreme temperatures progree Jul 2024 #3

Lovie777

(15,009 posts)

1. Ough..........................

Reply to hatrack (Original post)

Mon Jul 1, 2024, 08:07 AM

Jul 2024

and there are life forms that thru adaption can survive there. The wonders of nature.

usonian

(13,861 posts)

2. Fresno is predicted to be 116F next weekend. That's Death Valley weather in my book.

Reply to hatrack (Original post)

Mon Jul 1, 2024, 09:06 AM

Jul 2024

Prediction is down from 117. Foothills predicted to be 107F.

progree

(11,463 posts)

3. A small little change in average temperatures dramatically increases the number of days with extreme temperatures

Reply to hatrack (Original post)

Mon Jul 1, 2024, 05:02 PM

Jul 2024

Last edited Mon Jul 1, 2024, 11:19 PM - Edit history (1)

if, for example, the average daily high in July in some locale like Phoenix is 105 degrees with a 4 degree standard deviation, and normally distributed:

then the number of July days when the high is 117 or above (3 standard deviations above the mean) is 0.1350% of July days.

In Excel, the formula for finding the area under the normal distribution from 117 to infinity with an average of 105 and standard deviation of 4 is:
=1-NORM.DIST(117,105,4,TRUE)
which gives an answer of 0.001350 which is 0.1350%

OK, so no biggie. So what?

Now lets say that due to climate change so far, the average July daily high temperature has shifted by just 2% to the right, from 105 to 107.1

then the number of July days when the high is 117 or above changes to 0.6662% of July days.

That's a 4.94 fold increase (394% increase) in the number of 117+ degree July days for just a 2% increase in the average.

Shift the average 4% to the right, from 105 to 109.242, and you get 2.622% of July days are 117+, a 19.424 fold increase (1842% increase) in the number of 117+ July days.

More details on the methodology at https://www.democraticunderground.com/1127174636#post1

For the daily highs in July 2023 in Phoenix I used

https://weatherspark.com/h/m/145521/2023/7/Historical-Weather-in-July-2023-at-Phoenix-Sky-Harbor-International-Airport-Arizona-United-States#Figures-Temperature
# Average daily July high in 2023: about 105 degrees, the 10% - 90% confidence bands are about 100 to 110 (reading from the graph). Bandwidth = 10.
# The 10 to 90% confidence interval of the normal distribution is -1.281552sigma to +1.281552sigma
# When the 10 to 90% confidence bandwidth is 10, then
. . the standard deviation, Sigma, is 3.90152: ( 10/2 = 5, 5/1.281552 = 3.90152 ) I rounded to 4 in the above example

=====================================

The same principle applies to other climate change events, e.g. the severity of storms or what have you -- a small shift in the average results in a huge increase in the number of extreme events.

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