Record overnight high temperatures.

[Eddie Haskell]

"While the current heat wave has recorded 12 all-time daily highs so far this month, it also has registered 98 all-time overnight highs, the National Oceanic and Atmospheric Administration reported at a briefing Thursday."

http://old.news.yahoo.com/s/ap/20110722/ap_on_re_us/us_heat_wave

This seems odd. Why would it be staying hotter at night? Is this a trend or just a one time effect set up by atmospheric conditions? Any experts out there.

[fascisthunter]

1. I'm worried about the elderly in Boston

and those who are too poor to own adequete air conditioning... I think I'm sinking into a bit of depression myself knowing how bad things are going to get, and it's not just the heat.

[haele]

2. High humidity holding the heat in?

That's what I've always found kept the heat in at night. An nightly inversion layer or light cloud/fog cover with little or no breeze is miserable in the summer. Clear nights or windy nights will cool off far quicker once the sun goes down.

Haele

[Eddie Haskell]

4. Do you know if humidity levels are trending higher?

Is this a function of warming in general or just a two-week aberration? Does the high humidity generate more intense storm activity?

[haele]

11. Warmer waters tend to evaporate more, so it's possible there's more humidity.

And there is evidence that the ocean temperature is rising.

But I'm not an climatologist, so I can't really answer that question.

Haele

[pscot]

13. All of the above

if you believe the science guys.

[kestrel91316]

3. Well, hotter nights were SPECIFICALLY predicted to be a consequence of

global warming by the world's climatologists.

Here in SoCal I notice that out increasingly hot summer nights are accompanied by much humidity. When it's bone dry it cools off at night. And when I was a kid I think they taught that in school - that deserts cool off a lot at night because they are so dry.

[MuseRider]

5. They did say that

and I have been watching for the last several years as our night time lows have stayed very high. I would not be concerned if it was only part of the time but it seems that the summer time lows are very high. I have not looked into the trends for this area but night before last our heat index at 10PM was 102. I KNOW that is not usual. Last night was almost as bad.

[Eddie Haskell]

6. That's interesting, sounds like a dangerous trend ...

dangerous and expensive. My heat pump's been running day and night. My electric bills are going higher even though the rates are down and my degree days are relatively stable year to year. There could be a lot of reasons for higher usage, but this bears watching.

[phantom power]

8. yes, it's almost like something is holding heat in, like a... a...

the word is on the tip of my tongue.

[Eddie Haskell]

9. Found this explanation of the feedback effect.

http://www.aip.org/dbis/AGU/stories/20093.html

This is not only expected, it's self-reinforcing.

[kestrel91316]

10. Ya think???

[BeFree]

7. Upper wind patterns

At this link are graphics detailing the upper air wind patterns. As you can see the winds are coming from near the equator, running west from Africa then curving north over the Gulf of Mexico and heading towards Canada. This pattern has been in effect for a month now. The usual pattern, imo, the winds head north off the east coast of Florida. As it stands now, the cooler westerlies from the pacific are being blocked from their usual course which is to head east cooling the interior.



http://tropic.ssec.wisc.edu/real-time/dlmmain.php?&basin=atlantic&sat=wg8&prod=dlm1&zoom=&time

[Kolesar]

12. It used to be that a starry night would cool things down, but CO2 reflects the heat back

So we don't get the reprieve of a chilly morning.

[emmadoggy]

14. Yes, as others have said, higher nighttime lows are predicted with

climate change. As a matter of fact, my regional National Weather Service office just released new climate normals for our area. ACROSS THE BOARD, every single month had a higher average nighttime low.

http://www.crh.noaa.gov/news/display_cmsstory.php?wfo=arx&storyid=70491&source=0