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Old 07-26-2016, 11:16 AM
 
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Quote:
Originally Posted by Fleet View Post
Not really really cherry-picking, just posting some relevant data and information, like the June figures.

Here is more interesting info...

City---------------- Average July Max.-- Record July Max.

Thermal, CA------- 107 degrees F------ 126 degrees F

Indio, CA---------- 107----------------- 125

Buckeye, AZ------ 108------------------ 125

Parker, AZ-------- 109------------------ 127

Tacna, AZ-------- 107------------------- 126
Yeah, but places with higher average highs don't see record highs much higher than the high 120s or low 130s. It's not a linear relationship. One of the main reasons that some places see relatively "cool" summer highs of 107 degrees is that they can witness periods of storm activity or weak cold fronts that bring the averages down. A few double-digit highs can do it. Places like Death Valley, with more stable weather, won't see these cool periods, but their hot periods aren't that much different from the places you listed. Make sense?

Kuwait never sees double-digit highs in the summertime, which is why its averages are much, much higher than of the towns you listed. But its record highs are not proportionately higher. The really, really hot deserts are very stable.

Last edited by arctic_gardener; 07-26-2016 at 11:33 AM..

 
Old 07-26-2016, 01:24 PM
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Location: Western Massachusetts
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reposting this from an thread on Death Valley:

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

Quote:
Originally Posted by wavehunter007 View Post
That's what I'm leaning toward = the physics of such an event must be very rare, though who really knows if it is truly impossible. If NWS/NOAA is fully accepting of the 129 F reading (and they had more modern equipment by this time)...I just can't help but think that the puny length of the tempreture record hides much bigger events that have happened before. An old climatologist used to say there is no such thing in nature as a one time event - lol.
Thinking about the physics of creating a hot temperatures, to get a hot temperature in one day is determined by a balance of competing factors. Here are my thoughts. Factors creating heat:

1) Some type of fixed high pressure system allowing heat to build up. Death Valley has the right topography
2) Strength of the sun (this doesn't really change much for Death Valley)
3) Hotter air from elsewhere (plays a big role at higher latitudes but not for a place like Death Valley, which in the summer is generally the hottest in the continent)

Factors keeping it cool:

1) Heat loss to evaporation, also called latent heat. Probably irrelevant for death valley, but for humid tropical locations, and in mid latitude locations with humid heat (such as Massachusetts), a big factor in preventing temperatures much into the triple digits. Goes up something like an exponential with temperature (or dewpoint? ). I'd have to check
2) Radiation loss; proportional to the fourth power of temperature. For Death Valley the amount radiated away must be large. The bowl shape of Death Valley means some of what gets radiate to space, gets reabsorbed by the walls, reheating somewhat.

I think all location have physical limits that prevent very hot temperatures. At some point the probability must drop to zero. Maybe 136°F is possible in Death Valley, but 150°F? I doubt it's physically possible in the current earth, but maybe in a time in the earth's past when it was much hotter or an unusual geography, see these two threads.

Quote:
As far as the heat records up in your area/New England I'm a bit suprised to see that it has been 30 years since there was 100 F temp reading. Are you sure this is correct? In the Tri-State area many stations have record 100 F temps in the last 5 or 10 years I think...and even the coastal stations like Atlantic City and Bridgeport have hit a 100 F or more in the last decade.
I gave it for just one station, Amherst, MA. But as you go further north the chance of extreme heat dies down, though Westfield, MA (in the region, slightly further south) has recorded triple digits temperatures numerous times in the last decade. By the tri-state area, heat waves top out around the low 100s (maybe 101-103°F at most). Amherst, MA will be a few degrees cooler. Anyway, I thought these graphs I made would illustrate what's going on:

For three weather stations, I graphed the number of days per year on average above a certain temperature. The three I chose were Death Valley, CA, Amherst, MA and San Francisco, CA [Mission District, one of the warmest parts of the city]. The current Death Valley weather station goes back to 1961, so for all three I used a time range of 1961-2012 to be consistent. For the San Francisco station, the hottest temperature recorded during that time period was 103°F, for the Amherst station it was 99°F and for the Death Valley station 129°F. For all them, the hottest temperature was recorded multiple times (three times for Death Valley, two for the others). Go 1°F cooler and it's more common by a large factor. 13 days for Amherst, 13 for Death Valley, and... 3 days for San Francisco. San Francisco, being a marine station, behaves much differently than the others. Even though Death Valley is much hotter than Amherst, the likelihood of the hottest temperatures drop off similarly. For Amherst and Death Valley, the drop off is steep within 10°F of the record high, every 1°F warmer becomes about half as likely, and a steeper drop off right near the record. The only way to show the trend and include cooler temperatures is to use a log scale. To set all them on the same, axis, I set 0 to equal the temperature of the hottest recorded day for a particular station. -1 would be 1°F cooler than that, so 98°F for Amherst, 102°F for San Francisco, 128°F Death Valley. The y axis is number of days > than a particular temperature.



I thought it was very interesting that Amherst and Death Valley have the same shape, almost as if weather physics creates the same statistics.

On a log scale, again, I made another graph just with Death Valley. Unlike the previous graph, it's the number of days with a particular temperature / year. In math terms, the graph below is similar to a probability density graph while the previous one is similar to a cumulative density graph. The y-axis is the log (base 10) of the number of days at a certain temperatures.



I fitted a quadratic to the curve, shown with a dashed curve (almost a line but not quite). From the graph, a temperature of about 131°F should occur every 100°F, 134°F occur every 1000 years. Since it's a log scale, and the fitted curve is proportional to -x^2, the number of days goes down e^(-x^2), or it's a tail end of a Gaussian distribution. It may not be safe to extrapolate, as it could get even rarer with increased temperatures, but I doubt the curve would be less steep than the fitted gaussian. There may have been a better curve shape to fit, I don't know, but I've read gaussians may not be appropriate when fitting to rare events. If the global warmed, the fitted curve (dashed line) should shift to the left, but I think the slope would remain the same, so eventually very hot temperatures would be equally rare, just at slightly higher numbers.

Either way, statistically low 130s might be probable for Death Valley given enough time, without any climate change, upper 130s extremely unlikely.

Now here's San Francisco and Amherst plotted against real temperature (Death Valley is too different to plot together). This time the graph is cumulative, it's showing how many days are above a certain temperature:



Some interesting patterns. Hot days become much more in common in Amherst with just a few degrees cooler, but San Francisco doesn't climb the same: upper 80s is much more common than mid 90s for Amherst, the difference less drastic for San Francisco. Below 90°F, the San Francisco curve become a straight line. Since it's on a log scale, a straight line means a warm day become exponentially less likely with warmer temperatures. At the highest temperatures, hotter days became less likely more than than exponentially, and cooler than 80°F, the number doesn't change very fast and by the low 60s, San Francisco catches up. On a linear scale, you can see what happens for cooler temperatures:



Again cumulative.
 
Old 07-26-2016, 04:29 PM
 
Location: Northridge/Porter Ranch, Calif.
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Quote:
Originally Posted by Blind Cleric View Post
No, but he may be able to work at scratching that 134 reading as the all time record.

After all, he was one of the guys reviewing the now discredited middle east temperature that "broke" Death Valley's record.

One of the things suspicious about that reading is that there were three other days during that week that recorded 130.

It's never been that hot there since.
Even Chris Burt admits the 134 temp at Death Valley could be a "500-year event," occurring only once every few hundred years.

The thermometer at the site of the "136 degrees" temp was outdated even back then. The thermometer at Death Valley was no doubt more modern and accurate.

I don't see anything suspicious about those three different readings; it was in the summer, after all!

Let's not forget that in 1917, there were 43 consecutive days of readings 120 degrees and higher.

Death Valley is a land of extremes, sometimes in a short period of time. For example, the record minimum temp actually happened in the same year as the record maximum temp! (15 degeres F on Jan. 8, 1913).

Another example: Even though it is the driest area in the country, during the 1969-'70 winter and spring season, there was a lake in a portion of Death Valley.

Yet another example: On the same day, the heat can be dangerous on the valley floor (~120 degrees) and also dangerous in the Panamint Mountains which can still have snow on the higher peaks and temps in the 30s.
 
Old 07-26-2016, 05:23 PM
 
Location: Live:Downtown Phoenix, AZ/Work:Greater Los Angeles, CA
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Quote:
Originally Posted by Fleet View Post
Even Chris Burt admits the 134 temp at Death Valley could be a "500-year event," occurring only once every few hundred years.

The thermometer at the site of the "136 degrees" temp was outdated even back then. The thermometer at Death Valley was no doubt more modern and accurate.

I don't see anything suspicious about those three different readings; it was in the summer, after all!

Let's not forget that in 1917, there were 43 consecutive days of readings 120 degrees and higher.

Death Valley is a land of extremes, sometimes in a short period of time. For example, the record minimum temp actually happened in the same year as the record maximum temp! (15 degeres F on Jan. 8, 1913).

Another example: Even though it is the driest area in the country, during the 1969-'70 winter and spring season, there was a lake in a portion of Death Valley.

Yet another example: On the same day, the heat can be dangerous on the valley floor (~120 degrees) and also dangerous in the Panamint Mountains which can still have snow on the higher peaks and temps in the 30s.
Bishop is another even better comparison once you account for elevation. The Owens Valley is right next to Death Valley, and Bishop's all time record is 110, at 4,150 ft, that would translate to 123-128 at 280ft below sea level, so again, supporting the 129 reading as tops
 
Old 07-26-2016, 08:12 PM
 
Location: MD
5,984 posts, read 3,441,311 times
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Quote:
Originally Posted by nei View Post


I fitted a quadratic to the curve, shown with a dashed curve (almost a line but not quite). From the graph, a temperature of about 131°F should occur every 100°F, 134°F occur every 1000 years.
Some errors there. Assuming your Gaussian fit is realistic, we would expect that:

130 would occur every 20 yrs
131 would occur every 50 yrs
132 would occur every 100 yrs
133 every 300 years
134 every 1000 years

but, there might be a huge standard deviation...

Quote:
Since it's a log scale, and the fitted curve is proportional to -x^2, the number of days goes down e^(-x^2), or it's a tail end of a Gaussian distribution. It may not be safe to extrapolate, as it could get even rarer with increased temperatures, but I doubt the curve would be less steep than the fitted gaussian. There may have been a better curve shape to fit, I don't know, but I've read gaussians may not be appropriate when fitting to rare events.
Around the world each summer, you see hundreds of readings in the 50-51C range, but as you go up to the 51-52C range there are only a few dozen each year, from 52-53C only a small handful, and above 53C none (don't quote me on that; I'm just mentally extrapolating from data I follow within the Middle East but I could be way off).

Surprisingly enough, a Gaussian would fit these fairly well...

However, I would have thought that the Gaussian decay is a bit too weak. I thought that, for instance, a better fit might be e^(-c*x^3), or some power greater than 2. Guess not?

Quote:
If the global warmed, the fitted curve (dashed line) should shift to the left, but I think the slope would remain the same, so eventually very hot temperatures would be equally rare, just at slightly higher numbers.
If the globe warmed, the fitted curve would presumably move to the right, not left. But the conclusion is unchanged.

Last edited by Shalop; 07-26-2016 at 08:23 PM..
 
Old 07-26-2016, 11:45 PM
 
Location: Northridge/Porter Ranch, Calif.
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Quote:
Originally Posted by FirebirdCamaro1220 View Post
Bishop is another even better comparison once you account for elevation. The Owens Valley is right next to Death Valley, and Bishop's all time record is 110, at 4,150 ft, that would translate to 123-128 at 280ft below sea level, so again, supporting the 129 reading as tops
Temperature increase by elevation change can be a guide to go by but is by no means 100% accurate. Air flow and air currents can make a big difference.

This is a photo of the Greenland Ranch (Furnace Creek) station from 1922...

 
Old 07-27-2016, 06:50 AM
 
Location: La Isla Encanta, Puerto Rico
1,192 posts, read 3,474,645 times
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In Kuwait, the 130+- days would usually be when there was a strong wind from the deserts to the North in Iraq (The Shamal) or east from Saudi (Samoon or "poisson wind"). The winds off the interior desert would shut down the normal bits of humidity from the Gulf and make incredibly dry conditions. Lots of people would get nose bleeds from the 10% humidity.

It was really amazing, though, how well evaporative cooling worked. I'd get into our large camp swimming pool with its 90 degree hot tub-warm water (without a heater!) and swim until I got dizzy and when I got out into that wind the water would evaporate so fast I'd even get a chill (for a few short minutes only before it felt like Hades again).

The very worst thing about this was the unbelievable sandstorms the hot desert winds would kick uphttp://static.panoramio.com/photos/large/50501991.jpg. One of the worst of recent years accured in March 2011 (see picture) and it was bad enough to shut down the U.S. Air Base. Our villa had two or three inches of sand and dust just from the partly open bathroom ventilation windows.
 
Old 07-27-2016, 07:25 PM
 
Location: Western MN
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Quote:
Originally Posted by arctic_gardener View Post
Probably low 100s along the Kuwaiti coast in shallow water, and mid-90s offshore.

It always amazes me that people view Dubai as a beach destination. In winter, maybe, but in the summer, you'd have to be certifiably mentally ill to swim in water hot enough to give you hyperthermia.
Living in MN it never occured to me that swimming water could get so warm as to give a person hyperthermia.
 
Old 07-27-2016, 09:08 PM
 
Location: Live:Downtown Phoenix, AZ/Work:Greater Los Angeles, CA
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Average hot tub/jacuzzi temp is 104°F/40°C, and it's only recommended to be in water that hot for 15 mins tops
 
Old 07-27-2016, 09:23 PM
 
3,212 posts, read 3,164,805 times
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Quote:
Originally Posted by FirebirdCamaro1220 View Post
Average hot tub/jacuzzi temp is 104°F/40°C, and it's only recommended to be in water that hot for 15 mins tops
I wonder what the cold water equivalent discomfort is to that temperature.
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