APOD: A Roll Cloud Over Wisconsin (2023 Aug 20)

[APOD Robot]

A Roll Cloud Over Wisconsin

Explanation: What kind of cloud is this? A type of arcus cloud called a roll cloud. These rare long clouds may form near advancing cold fronts. In particular, a downdraft from an advancing storm front can cause moist warm air to rise, cool below its dew point, and so form a cloud. When this happens uniformly along an extended front, a roll cloud may form. Roll clouds may actually have air circulating along the long horizontal axis of the cloud. A roll cloud is not thought to be able to morph into a tornado. Unlike a similar shelf cloud, a roll cloud is completely detached from their parent cumulonimbus cloud. Pictured here, a roll cloud extends far into the distance as a storm approaches in 2007 in Racine, Wisconsin, USA.

<< Previous APOD

This Day in APOD

Next APOD >>

[orin stepanek]

I remember passing under a roll cloud comming home from Lincoln
when I had to see a skin specialist! Anyway There was a
temperature drop ang after driving about 10 miles; it started
to hail! I pulled to the side of the road and then boom-sploosh;
a big hail stone about the size of a softball hit my windshield!
I was lucky it was all slush!

LaundryCat.gif (4.48 MiB) Viewed 2888 times

This kitty would be a good rebounder!

[RALF99]

I am sorry but when did clouds get to be part of astronomy? Clouds are the nemesis of astronomers. Please save cloud postings for WPOD.

[bystander]

I am sorry but when did clouds get to be part of astronomy? Clouds are the nemesis of astronomers. Please save cloud postings for WPOD.

Here's a reply from Dr. Nemiroff to complaints about a different cloud image.
APOD: 2008 Jan 22 - Shelf Cloud Over Saskatchewan ~ Discussion

I chose and wrote this APOD, and here are some of my thoughts on the criticism that this APOD is not true to APOD's astronomy theme.

First of all, I do think that this criticism does have some merit. How would I feel if my favorite classic-rock radio station suddenly played Beethoven? Possibly the same way -- especially if the radio station advertised that it played rock music.

They why did we run this image? Well, in some sense APOD is like a blog. Sometimes Jerry or I will just run things we think are cool. Fuzzy ideas that swim around in my brain when choosing a non-astronomical cool image include the wow factor of the image, whether the sky is at all involved, the educational content of the image, the scientific content of the image, and whether the image could be useful in the future as a link from a more main-stream astronomically-oriented APOD. I also hope that non-astronomy images are useful in drawing people with more diverse interests to view APOD and therefore become interested in astronomy.

Other arguments include "the Earth is also a planet" and that the term "astronomy" is actually somewhat vague these days.
See: http://en.wikipedia.org/wiki/Astronomy# ... physics.22
If one is to take the term "astronomy" at its Greek roots then APOD should only show star images! But these reasons are secondary.

APOD runs non-astronomy images about once a month or so. We have always done this. If you don't like it, I apologize, but I think it will continue. I still hope that, for the most part, everyone, even the astronomy purists, will still find APOD enjoyable and educational.

- RJN

[orin stepanek]

I am sorry but when did clouds get to be part of astronomy? Clouds are the nemesis of astronomers. Please save cloud postings for WPOD.

Here's a reply from Dr. Nemiroff to complaints about a different cloud image.
APOD: 2008 Jan 22 - Shelf Cloud Over Saskatchewan ~ Discussion

I chose and wrote this APOD, and here are some of my thoughts on the criticism that this APOD is not true to APOD's astronomy theme.

First of all, I do think that this criticism does have some merit. How would I feel if my favorite classic-rock radio station suddenly played Beethoven? Possibly the same way -- especially if the radio station advertised that it played rock music.

They why did we run this image? Well, in some sense APOD is like a blog. Sometimes Jerry or I will just run things we think are cool. Fuzzy ideas that swim around in my brain when choosing a non-astronomical cool image include the wow factor of the image, whether the sky is at all involved, the educational content of the image, the scientific content of the image, and whether the image could be useful in the future as a link from a more main-stream astronomically-oriented APOD. I also hope that non-astronomy images are useful in drawing people with more diverse interests to view APOD and therefore become interested in astronomy.

Other arguments include "the Earth is also a planet" and that the term "astronomy" is actually somewhat vague these days.
See: http://en.wikipedia.org/wiki/Astronomy# ... physics.22
If one is to take the term "astronomy" at its Greek roots then APOD should only show star images! But these reasons are secondary.

APOD runs non-astronomy images about once a month or so. We have always done this. If you don't like it, I apologize, but I think it will continue. I still hope that, for the most part, everyone, even the astronomy purists, will still find APOD enjoyable and educational.

- RJN