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Record hottest rainfall


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oh my

. With the air temperature a sizzling 109°F (43°C) at the time of the June 4 thunderstorm in Mekkah, the raindrops could easily have been heated to a temperature of over 105°F (41°C) by the time they reached the surface!

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Imagine the dewpoint.

That's actually the key to what the actual temperature of the falling rain was.

If it was dry (say, 30% RH which would give a dewpoint of 71F. Ha!), then your rain would only be about 81F as it fell, since that's the wet-bulb temperature with those stats. If it was more humid (say, 50% RH which would give a dewpoint of 86F :unsure:), the rain would be falling at 91F. Hot, but not 105F. The writer of the article doesn't seem to understand evaporative cooling.

You'd need a dewpoint of 104F (for a RH of 86%) in order to get the wet-bulb temperature to (and thus raindrops to have a temperature of) 105F.

EDIT: Ya, here's the observation:

http://www.wunderground.com/history/airport/OEMK/2012/6/4/DailyHistory.html

METAR OEMK 041400Z 00000KT 9000 TSRA FEW030CB SCT040 SCT100 43/14 Q1004

With those numbers, the RH is 18.4% and the wet-bulb temperature is 74.6F... so ya, falling raindrops wouldn't be 105F. They would be much closer to 75F.

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With those numbers, the RH is 18.4% and the wet-bulb temperature is 74.6F... so ya, falling raindrops wouldn't be 105F. They would be much closer to 75F.

Good analysis but I think the rain drops would be warmer than 75 F. As was noted in the article, these were probably large rain drops and they were falling through a deep layer of warm air and a fast speed. There isn't enough time for that much evaporative cooling to take place. I remember from undergraduate thermodynamics that we had to stand there for a long time spinning the sling psychrometer to get an accurate wet bulb temperature.

The RH stayed low and the temperature stayed high despite the rain. That indicates that not much evaporation was going on. Furthermore, any evaporation that does occur would not require as much energy because the latent heat of vaporization is higher at 100 F than at room temperature. So any evaporation was cancelled out by warming from conduction. I suspect they were closer to 90 F.

Obviously we would have to make some more detailed calculations and experiment to know for sure :-)

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its not as bad as this!! :axe:

On July 8, 2003, the world-record high dew point of 95 was recorded at Dhahran, Saudi Arabia, and when combined with that afternoon's temperature of 108 produced a heat index of 174 degrees.

widespread dust with a temperature of 113°F...why would anyone live there

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Good analysis but I think the rain drops would be warmer than 75 F. As was noted in the article, these were probably large rain drops and they were falling through a deep layer of warm air and a fast speed. There isn't enough time for that much evaporative cooling to take place. I remember from undergraduate thermodynamics that we had to stand there for a long time spinning the sling psychrometer to get an accurate wet bulb temperature.

The RH stayed low and the temperature stayed high despite the rain. That indicates that not much evaporation was going on. Furthermore, any evaporation that does occur would not require as much energy because the latent heat of vaporization is higher at 100 F than at room temperature. So any evaporation was cancelled out by warming from conduction. I suspect they were closer to 90 F.

Obviously we would have to make some more detailed calculations and experiment to know for sure :-)

It's true that large raindrops are probably not going to cool to the wet bulb temperature, but I suspect it would still be below 90F. Certainly not 105F. :P

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No idea what the dewpoint was, but 48ºC in Monahans, TX in 1994 with dry thunderstorms nearby that started a fire that burned all the way to the road at the edge of MAF airport.

Working in the sand dunes around Monahans, relative humidty may have been reasonable, but fireproof Nomex suits, manual labor, and Sun reflecting off the sand. Oil wells, sand dunes, camels and heat, only in Texas.

Camel tours however...

monahans3.jpg

Monahans_Sandhills_at_Sunrise.jpg

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No idea what the dewpoint was, but 48ºC in Monahans, TX in 1994 with dry thunderstorms nearby that started a fire that burned all the way to the road at the edge of MAF airport.

Working in the sand dunes around Monahans, relative humidty may have been reasonable, but fireproof Nomex suits, manual labor, and Sun reflecting off the sand. Oil wells, sand dunes, camels and heat, only in Texas.

Camel tours however...

monahans3.jpg

Monahans_Sandhills_at_Sunrise.jpg

What does this have to so with the topic currently being discussed, ramblED?
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its not as bad as this!! :axe:

On July 8, 2003, the world-record high dew point of 95 was recorded at Dhahran, Saudi Arabia, and when combined with that afternoon's temperature of 108 produced a heat index of 174 degrees.

Is there a place to find historical weather data for such places as Dhahran? I remember sunbathing there in 2001 at the beginning of May. It was so hot, I had a migraine after being out for 30 minutes. Definitely the hottest I have ever experienced.

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its not as bad as this!! :axe:

On July 8, 2003, the world-record high dew point of 95 was recorded at Dhahran, Saudi Arabia, and when combined with that afternoon's temperature of 108 produced a heat index of 174 degrees.

And earlier that day, the airport at Dharan reported zero visibility with fog at 86F. That's like being in a steam bath with no way out.

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Hottest rain shower ever?

http://www.wundergro...l?entrynum=2114

Incredible. Wonder what the folks there thought.

From the blog

As for your question, yep according to this

"According to weather records researcher Maximiliano Herrera, this is the highest known temperature that rain has fallen at, anywhere in the world."

However, I do find it hard to believe the desert southwest hasn't had temps that high with the monsoon.

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Incredible. Wonder what the folks there thought.

From the blog

As for your question, yep according to this

"According to weather records researcher Maximiliano Herrera, this is the highest known temperature that rain has fallen at, anywhere in the world."

However, I do find it hard to believe the desert southwest hasn't had temps that high with the monsoon.

If it gets cloudy first, the temperature begins dropping, and the air evaporatively cools before it begins to rain. That's probably why this is so difficult to happen.

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Nope, the Desert Southwest is usually hottest before the monsoon begins. Once the monsoon does start, the increased moisture in the atmosphere puts a cap on temperatures.

However, we can get high based boomers during that pre monsoon heat blast-the dreaded Inverted V sounding. Most of the time the storms produce high winds, blowing dust and dry lightning but on occasion some rain does reach the ground. Because the moisture for this type of pattern comes in at fairly high levels, clouds do not form until we have maxed out for the day temperature wise.

Steve

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The posted observation for Mecca showed a dewpoint depression of 29C (43/14 TT/TdTd)and 9km (~6 mi)with TSRA. Rainfall was obviously not very heavy and if wehad big drops could have been melted hail which would be reasonably cool without evaporation. Aside from that someone in or around Mecca probably ha and the living crap beat out them by a very violent downburst. We;ve seen temperature dewpoint setups very similar (especially around PHX and to the west) with boomers and usually see 70-80 mph microburst winds, haboobs and on occasion some really torrential rain. Unlike Cochise and Santa Cruz Counties and in the mountains, areas of Arizona west of the Rim and the Santa Catalina and Santa Rita Mountains do not see that much afternoon cloud cover prior to the appearance of the late afternoon storms-especially if we are talking about Rim shots where topography and terrain driven wind flow patterns prevailed with very hot air inflowing towards the storms coming off the mountains. PHX has seen temperatures and dewpoints in the 105-110 range/ 60's at storm onset-doesn't last long since the former drops and the latter skyrockets when the outflow hits. FTR Yuma has seen 113/77 for their combination though there were no storms that day (at least not in Yuma). It would be interesting to see what happened after that observation was taken.

Steve

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its not as bad as this!! :axe:

On July 8, 2003, the world-record high dew point of 95 was recorded at Dhahran, Saudi Arabia, and when combined with that afternoon's temperature of 108 produced a heat index of 174 degrees.

Siri Island, an Iranian oil port on the Persian Gulf, frequently has summertime TDs 85-90 (according to wunderground), though the temps rarely get much above 100 due to the water all around. When the wind kicks up, the reported conditions are sometimes listed as "sand". I can't imagine being in a TD-90 sandstorm; must be akin to being tarred and feathered.

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