Bright aurora are forecast as likely for tonight :-)

January 10, 2014 | By | 4 Comments
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Update 11 January 2014 The aurora did not eventuate last night – in spite of the really positive forecast indicating one would occur. Not that it will help your disappointment in missing out on seeing one (and mine), the experts have worked out why no aurora eventuated.

Original post 10 January 2014 As an eternal optimist, I would like to point out that Spaceweather.com is predicting a 85% chance of ‘severe’ aurora for high latitudes and a 50% chance of aurora for mid-latitudes (Tasmania, possibly Southern Victoria and Western Australia). The U.S.A.’s National Weather Service Space Weather Prediction Center concurs ‘…The initial structure of this CME has been relatively weak in strength, but that said, it generally takes on the order of 24 hours or more for the full event to transpire and stronger storming is certainly still possible‘.

Optimism is required given that the forecast aurora did not eventuate last night, likely leaving people who went out to look slightly annoyed. Speaking for myself, I stayed up much of the night hoping to see an aurora from Canberra (which I have once before). I can confirm the reason for the no-show. The coronal mass ejection (CME) which was forecast to arrive around 6 pm AEST / 7 pm AEDT yesterday didn’t actually do so until around 7 am AEST / 8 am AEDT this morning! Great if you happened to be in Norway – where they saw some lovely aurora but not for Australian observers as it was daytime.

The reason behind the slow arrival may be a coronal hole on the Sun which produced a fast coronal wind which pushed most of the mass of the CME away from the Earth. This meant that less plasma from the Sun arrived at the Earth than was expected, and it arrived much later than expected.

Back to the reason for optimism for tonight. Spaceweather.com has commented that it is possible that the Earth might pass through the wake of the CME over the next 24 hours – resulting in brighter aurora. The downside is of course the Moon will be even brighter tonight which will interfere with the visibility of faint aurora.

So if you are optimistic like me, the advice from aurora watching websites is to look around local midnight to the South for slowly moving clouds of reddish or if you are further South – (Hello Tasmania!) greenish faint glowing clouds of light. You might also want to wait until around Moon set tomorrow morning. Streetlights are not good and skies clear of cloud are also required. Finally it isn’t possible to predict exactly when they will occur (I got that question alot last night).

Finally, if you do happen to see an aurora, please add a comment to this post page or tweet me (@Nightskyonline).

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This website is maintained by Paul Floyd. I am an amateur astronomer (and school teacher) with 25 years experience (as at 2015) in running a range of education and public astronomy outreach activities. As of January 2015, I have been providing astronomy information via the WWW for eighteen years.