Sunday, July 19, 2020

As Hot, Sticky Weather Descends on Much of the Country This Weekend, It's Time To Talk About Nocturnal Corn Sweats

A subject of some interest to, uhhh, natural gas traders and, uhh, the sweaty multitudes.
Yeah, that's the ticket, natural gas geeks and regular folks.*
First up, from AgWeb:
http://data-services.wsi.com/200904-01/891672306/Image/Temperature/Highs%20-%20Forecast/SectorName/conus/Part/_day1

And from CityLab (now a Bloomberg property):

July 19, 2019, 12:10 PM PDT
How ‘Corn Sweat’ Makes Summer Days More Humid
It’s a real phenomenon, and it’s making the hot weather muggier in the American Midwest.  
As hot, sticky weather descends on much of the country this weekend, some of the stickiness in Midwestern cities may be due to an unexpected phenomenon: “corn sweat.”

That’s right. Even if you’re in the middle of a concrete jungle, those millions of acres of corn (and other crops) in the country’s heartland are still shaping your weather in powerful—and uncomfortable—ways.

“Under conditions like we have now where it’s very warm to begin with, and the atmosphere has a significant amount of moisture in it already, the crop is just adding moisture to that, making conditions feel even more humid,” said Dennis Todey, director of the U.S. Department of Agriculture’s Midwest Climate Hub.

How corn ‘sweats’
Plants, like humans, shed water when it gets too hot. In their case, they suck up water through their roots and then push it out through tiny holes in their leaves called stomata.

“When [water] converts from that liquid form to that gas form, it takes a lot of energy with it,” said Joe Lauer, a professor and corn agronomist at the University of Wisconsin. “The upshot is it cools the leaf down.”

But all that water a plant pushes out of its stomata goes somewhere: into the air.
The process is technically called transpiration or evapotranspiration, analogous to perspiration in animals. When it’s corn that’s evapotranspiring, the process is often dubbed “corn sweat,” a special nickname because of the prominent effect it can have on the weather.

One corn plant doesn’t make a big difference. But a full field can raise the dew point—a measure of how much water is in the air—by 5 degrees Fahrenheit. A single acre of corn can give off up to 4,000 gallons of water per day. And the U.S. has lots and lots of cornfields: more than 90 million acres.
https://assets.bwbx.io/images/users/iqjWHBFdfxIU/ilcv5pfXy0j0/v0/800x-1.png
The result is a wave of humidity that rolls across entire regions, from Denver to Pittsburgh.
The humidity from corn sweat is most pronounced in the cornfields themselves, but it reaches cities, too. There, it combines with the added heat from the urban heat island effect to create a particularly unpleasant stickiness.

“Once that moisture’s up in the air, it kind of just blows around with the general motion of the wind and weather patterns,” said Eric Ahasic, a National Weather Service meteorologist based in Minnesota.

The effect can be considerable. Ordinarily, high dew points above 80 degrees are only really seen along the coasts, especially near warm seas like the Gulf of Mexico. A day passes for humid in inland climates if the dew point passes 70 degrees.

“But what we’ve seen really develop recently in the last 10 [or] 20 years, we’ve seen those 80-degree dew points get up into the Midwest,” Ahasic said. “It’s actually that extra moisture being pumped out of the farm fields, and especially the corn.”....
....MORE

Huh, July 19th. I wonder if this is a seasonal thing.

Real phenomenon? Of course it's a real phenomenon:
Friday, July 22, 2016
Nocturnal Corn Sweats And the U.S. Heat Wave
Years ago I was corresponding with a reader in Kansas:
On Jun 4, 2008, at 9:06 PM, Climateer wrote:
...pps- Have you ever heard of Nocturnal Corn Sweats?
It's supposed to be one of the reasons for higher humidity.
98% sucks.
That's a technical term that all the best weather geeks use
She responded
nocturnal corn sweats!! no! never heard of them. I just fell of my chair I laughed so hard. Really? Seriously? I'm googling it to make sure you aren't pulling my leg.
Compared to last year, almost no one (along my drive into town, anyway) planted corn this year. which is good because it has been horribly, horribly wet at all the wrong times. lots of wheat though...
Over the next couple years I got a bit obsessed:
Nocturnal Corn Sweat News!
6/11/10 Climateer wrote
If you Google "nocturnal corn sweat" (or sweats) it still comes back 'No Results Found'.
Damn it.

I shall make it my mission to bring the term into common usage,
From every village and hamlet to the great metropoli, when some says "NCS" it won't be the National Cartoonist Society they refer to.
I have a dream that one day even the state of Mississippi, a state sweltering with the heat of injustice, sweltering with the heat of oppression...

Good grief, I'm channeling MLK.
Here's the latest from Northern Illinois University via the Elgin Courier-News:... I even tried remembering high school biology. She asked:

8/4/10 Can soybeans get night sweats too? Was out two mornings around dawn and soybe... 
8/4/10 Climateer wrote
...It's all about the pores.
Corn is one of the weird C4's, I've forgotten which group/subgroup soybeans are in.
And the CAM's, ah the CAM plants.

Nocturnal Bean Sweats...hmmmm
Some people laughed back then but they aren't laughing now:
Washington Post, July 18
St. Louis Public Radio, July 20
 
DesMoines Register, July 21
Murray State University, July 19
My work here is done.
See also:
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