<p>To add to Gordon's answer, Cyclone Twenty-five was also called Cyclone Raquel and it was an "off-season" cyclone, as the following <a href="http://www.abc.net.au/news/2015-07-01/rare-off-season-cyclone-forms-near-solomon-islands/6587690" rel="nofollow noreferrer">reported in the news</a>. It was the <a href="http://www.abc.net.au/news/2015-07-01/cyclone-in-july-weather-bureau-declares-raquel-no-threat/6585580" rel="nofollow noreferrer">first cyclone recorded in the region during July</a>.</p>

<p>The synoptic weather map the region on that day was</p>

<p><a href="https://i.sstatic.net/pYHLz.gif" rel="nofollow noreferrer"><img src="https://i.sstatic.net/pYHLz.gif" alt="West Pacific Weather Map"></a></p>

<p>Source: <a href="http://www.bom.gov.au/cgi-bin/charts/charts.view.pl?idcode=IDX0016&amp;file=IDX0016.201506300000.gif" rel="nofollow noreferrer">http://www.bom.gov.au/cgi-bin/charts/charts.view.pl?idcode=IDX0016&amp;file=IDX0016.201506300000.gif</a></p>

CC BY-SA 3.0
2015-11-18T04:21:10.853Z
2015-11-18T04:26:25.880Z
2015-11-18T04:26:25.880Z
Fred
<p>Today (February 22nd 2019) There are cyclones/typhoons/hurricanes in both the North and South Pacific - Wutip east of Philippines, Oma East of Australia.  They are not twin cyclones as defined above, having formed at different times, and being well over 22 degrees of latitude apart.  Never seen an asymmetrical pair like this before, maybe a function of increasing sea surface temperatures due to global warming.  Link to satellite pictures and text below:</p>

<p><a href="http://www.weatherzone.com.au/news/cyclones-update/529321" rel="nofollow noreferrer">http://www.weatherzone.com.au/news/cyclones-update/529321</a></p>

CC BY-SA 4.0
2019-02-23T05:42:53.577Z
2019-02-23T05:42:53.577Z
Keith Quick
<p>It does occasionally happen. Not often, because to kick-start a hurricane there has to be some rotation to start with, from the Coriolis effect, together with a sea surface temperature of >27 &deg;C (+ some other requirements such as lack of horizontal shear). This combination is best met during summer when one or other hemisphere is tilted towards the sun, so the hurricane seasons in both hemispheres tend to be 6 months out of synchronization. But there are occasional overlaps, as in this vector composite, found at <a href="http://www.wunderground.com/blog/JeffMasters/archive.html?year=2015&amp;month=06&amp;MR=1" rel="nofollow noreferrer">http://www.wunderground.com/blog/JeffMasters/archive.html?year=2015&amp;month=06&amp;MR=1</a> 
<a href="https://i.sstatic.net/6Z9KI.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/6Z9KI.png" alt="enter image description here"></a></p>

CC BY-SA 3.0
2015-11-18T16:44:46.873Z
Here's the source of the image : [earth.nullschool.net](http://earth.nullschool.net/#2015/06/30/1500Z/wind/surface/level/orthographic=-199.35,0.24,1197) - It's animated so you might be able to get a better visualisation. Link is for the appropriate date/location
Basic
CC BY-SA 3.0
2015-11-18T02:22:44.280Z
2016-07-05T02:40:08.733Z
2016-07-05T02:40:08.733Z
Gordon Stanger
<p>I'm teaching a physics class, and I'm getting to the point where we are talking about the Coriolis effect.  I usually show a couple of photos/videos showing a storm in the Northern Hemisphere and a storm in the Southern Hemisphere, and talk about why they rotate different directions. </p>

<p>However, it occurred to me that at some point in history, there could well have been two storms occurring in the same ocean but in different hemispheres.  Has this ever occurred?  This would most likely have to be in the Pacific or Indian Oceans (probably the Pacific, since from what I've gathered the Northern Indian Ocean is less active than most other cyclone basins.)  Ideally, a photo/video of this event would exist that I could show my students.</p>

CC BY-SA 3.0
2016-07-14T09:16:02.950Z
Coincidentally, as hinted at by a link from gansub, in the Pacific, this has been theorized as a cause or indication of forthcoming El Niño.
And it doesn't appear that anyone hit the key point of summary... they form in the western Pacific every 2-5 years, depending on definition (see the Schubert link at the top of gansub's answer), and do occasionally occur in the Indian as well (don't think any of the rare S Atl TC's have matched anything in the N Atl).
JeopardyTempest
<meteorology><tropical-cyclone>
Have there ever been simultaneous cyclones in the same ocean but different hemispheres?
Michael Seifert
# Have there ever been simultaneous cyclones in the same ocean but different hemispheres?

(Asked by: username_0 on 2015-11-18)

I'm teaching a physics class, and I'm getting to the point where we are talking about the Coriolis effect. I usually show a couple of photos/videos showing a storm in the Northern Hemisphere and a storm in the Southern Hemisphere, and talk about why they rotate different directions.

However, it occurred to me that at some point in history, there could well have been two storms occurring in the same ocean but in different hemispheres. Has this ever occurred? This would most likely have to be in the Pacific or Indian Oceans (probably the Pacific, since from what I've gathered the Northern Indian Ocean is less active than most other cyclone basins.) Ideally, a photo/video of this event would exist that I could show my students.

**Tags:** meteorology, tropical-cyclone

> **Comments:**
> **username_1**: Coincidentally, as hinted at by a link from gansub, in the Pacific, this has been theorized as a cause or indication of forthcoming El Niño. And it doesn't appear that anyone hit the key point of summary... they form in the western Pacific every 2-5 years, depending on definition (see the Schubert link at the top of gansub's answer), and do occasionally occur in the Indian as well (don't think any of the rare S Atl TC's have matched anything in the N Atl).  

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## 3 answers

### Answer by username_4 on 2015-11-18. Score: 9 | Accepted answer

It does occasionally happen. Not often, because to kick-start a hurricane there has to be some rotation to start with, from the Coriolis effect, together with a sea surface temperature of >27 °C (+ some other requirements such as lack of horizontal shear). This combination is best met during summer when one or other hemisphere is tilted towards the sun, so the hurricane seasons in both hemispheres tend to be 6 months out of synchronization. But there are occasional overlaps, as in this vector composite, found at <http://www.wunderground.com/blog/JeffMasters/archive.html?year=2015&month=06&MR=1>
[![enter image description here](https://i.sstatic.net/6Z9KI.png)](https://i.sstatic.net/6Z9KI.png)

> **Comments:**
> **username_5**: Here's the source of the image : [earth.nullschool.net](http://earth.nullschool.net/#2015/06/30/1500Z/wind/surface/level/orthographic=-199.35,0.24,1197) - It's animated so you might be able to get a better visualisation. Link is for the appropriate date/location  

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### Answer by username_2 on 2015-11-18. Score: 4

To add to username_4's answer, Cyclone Twenty-five was also called Cyclone Raquel and it was an "off-season" cyclone, as the following [reported in the news](http://www.abc.net.au/news/2015-07-01/rare-off-season-cyclone-forms-near-solomon-islands/6587690). It was the [first cyclone recorded in the region during July](http://www.abc.net.au/news/2015-07-01/cyclone-in-july-weather-bureau-declares-raquel-no-threat/6585580).

The synoptic weather map the region on that day was

[![West Pacific Weather Map](https://i.sstatic.net/pYHLz.gif)](https://i.sstatic.net/pYHLz.gif)

Source: <http://www.bom.gov.au/cgi-bin/charts/charts.view.pl?idcode=IDX0016&file=IDX0016.201506300000.gif>


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### Answer by username_3 on 2019-02-23. Score: 4

Today (February 22nd 2019) There are cyclones/typhoons/hurricanes in both the North and South Pacific - Wutip east of Philippines, Oma East of Australia. They are not twin cyclones as defined above, having formed at different times, and being well over 22 degrees of latitude apart. Never seen an asymmetrical pair like this before, maybe a function of increasing sea surface temperatures due to global warming. Link to satellite pictures and text below:

<http://www.weatherzone.com.au/news/cyclones-update/529321>


---

