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Routinely Death Valley hits 120 – 123 F in late July and August….every few years Death Valley hits 124 – 127 F….and even last year (or year before can’t remember which) Death Valley hit 127 F several times. So Death Valley seems to have no problem getting into the 120’s F….yet they can’t break that 130 F?
How come Death Valley come so close to 130 F so often….yet never breach that 130 F mark?
It seems like all places have their limits. Western Massachusetts routinely makes it into the 90s (about 13 times / year here) but 95 and above is a struggle (handful of times a year at most). Triple digits is really hard for my local station, it hasn't been recorded in 30 years.
Death Valley's pattern is similar, just with much higher temperatures. Something about the prevailing weather patterns makes the probability of high temperatures drop very quickly with temperature. Perhaps if you wait long enough, a very unlikely event will happen, or maybe the physics of such an event makes it impossible.
Death Valley averages 18 days/ year 120°F and above, 3 days / year 125°F and above, 127°F and above is than one / year. (All data is from 1981-2012)
It's difficult for all areas to breach their extreme records. It comes close, but no cigar. If Death Valley reached 131 F, then some would be like, well why can't it reach 135 F? 140 F? etc. etc. There's limits.
It seems like all places have their limits. Western Massachusetts routinely makes it into the 90s (about 13 times / year here) but 95 and above is a struggle (handful of times a year at most). Triple digits is really hard for my local station, it hasn't been recorded in 30 years.
Death Valley's pattern is similar, just with much higher temperatures. Something about the prevailing weather patterns makes the probability of high temperatures drop very quickly with temperature. Perhaps if you wait long enough, a very unlikely event will happen, or maybe the physics of such an event makes it impossible.
Death Valley averages 18 days/ year 120°F and above, 3 days / year 125°F and above, 127°F and above is than one / year. (All data is from 1981-2012)
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.
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.
It absolutely will happen, when the right conditions develop. Weather is unpredictable, and just about anything is possible. Its not a matter of if, but rather when. Just like when snow suddenly falls, in a location that that hasn't had snow in a 100 years, or a tornado hits an area that has never had a recorded tornado.
Just because a particular weather event has never occurred, doesn't mean that it is impossible. It just means that the conditions are not very likely to develop.
It absolutely will happen, when the right conditions develop. Weather is unpredictable, and just about anything is possible. Its not a matter of if, but rather when. Just like when snow suddenly falls, in a location that that hasn't had snow in a 100 years, or a tornado hits an area that has never had a recorded tornado.
Just because a particular weather event has never occurred, doesn't mean that it is impossible. It just means that the conditions are not very likely to develop.
But there's a limit to that too. I doubt it's even remotely possible for it to snow in Singapore or for Vostok Station to climb above freezing.....or for it rain in my hometown in July for that matter...
But there's a limit to that too. I doubt it's even remotely possible for it to snow in Singapore or for Vostok Station to climb above freezing.....or for it rain in my hometown in July for that matter...
depends on which interval you consider... If you consider the next 100 years, those events are pretty impossible to happen. But if you go further - considering the changes climate will probably have to undergo in the next thousand or 10000 years....those events might be possible.
depends on which interval you consider... If you consider the next 100 years, those events are pretty impossible to happen. But if you go further - considering the changes climate will probably have to undergo in the next thousand or 10000 years....those events might be possible.
Well, we're talking within our current climatic norms, could any set of freakish circumstances happen to make those extremely unlikely outlier events occur within our lifetime?
depends on which interval you consider... If you consider the next 100 years, those events are pretty impossible to happen. But if you go further - considering the changes climate will probably have to undergo in the next thousand or 10000 years....those events might be possible.
True, but will such extreme events happen within any of our lifetimes? Chances are slim to none.
But there's a limit to that too. I doubt it's even remotely possible for it to snow in Singapore or for Vostok Station to climb above freezing.....or for it rain in my hometown in July for that matter...
I agree, but the OP is not talking about anything extremely out of the limits. He is only talking about 5 degree difference over the normal high temperatures. I think it would be a safe bet that just about any location could beat their their extreme weather records for high or low temperatures by five degrees, if some unusual weather conditions developed.
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 twothreads.
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.
Last edited by nei; 06-15-2013 at 01:43 PM..
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