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Sunday, April 23, 2017

 

Geomagnetic warning and Aurora Watch (23-24 April)

The SWS has issued a geomagnetic warning and an aurora watch for 23-24 April due to a high speed stream from a recurrent coronal hole and the arrival of a coronal mass ejection (this caused strong aroral conditions yesterday, which was clouded out for mots of Australia). A G2 storm is predicted to start anywhere between 4pm to 7 pm, with G1 (minor) storm conditions thereafter.

If these geomagnetic events occur and  result in aurora they could be seen from Tasmania and Southern Victoria, weather permitting (the weather is rubbish). 

Currently Hobart Kindex is 5 and Velocity: 689 km/sec Bz: -2.0 nT Density = 8.0 p/cc  (so promising). The Moon is rising late in the morning, so evening skies will have little Moon interference, but cloud cover is predicted for Tasmanian and most of Southern Victoria.  However, the last occurrence saw nice displays through gaps in the cloud. Be patient, as the activity may rise and fall as the magnetic polarity of the wind may fluctuate significantly.

Dark sky sites have the best chance of seeing anything, and always allow around 5 minutes for your eyes to become dark adapted.

As always look to the south for shifting red/green glows, beams have been reported consistently over the last few aurora, as well as bright proton arcs and "picket fences".

If you are up early on the morning of the 24th look for the crescent Moon near Venus.

Here is the near-real time satellite view of the clouds http://satview.bom.gov.au/
Cloud cover predictions can be found at SkippySky.  

The all sky aurora camera in Northern Tasmania at Cressy is being upgraded and is not yet online.

SUBJ: SWS GEOMAGNETIC DISTURBANCE WARNING 17/21 ISSUED AT 2323UT/21 APRIL 2017 BY THE AUSTRALIAN SPACE FORECAST CENTRE.
On 22 April the geomagnetic activity will remain elevated due to a CME arrival.
A recurrent coronal hole is expected to be geoeffective on 23-24 April.
INCREASED GEOMAGNETIC ACTIVITY EXPECTED DUE TO CORONAL HOLE HIGH SPEED WIND STREAM FROM 22-24 APRIL 2017
_____________________________________________________________

GEOMAGNETIC ACTIVITY FORECAST
22 Apr: Active
23 Apr: Active to Minor Storm
24 Apr: Minor Storm
==============================================================
SUBJ: SWS AURORA WATCH
ISSUED AT 0010 UT ON 23 Apr 2017 by Space Weather Services
FROM THE AUSTRALIAN SPACE FORECAST CENTRE

The Earth is currently under the influence of very high solar wind
speeds from a combined effect of the 18 April CME and high speed
streams from a recurrent,negative polarity coronal hole. As a
result,the geomagnetic conditions at earth could reach minor storm
levels today with isolated chance of major storms. Auroras may be
visible tonight (23 April) in Tasmania and possibly from the coastline
of Victoria. Aurora alerts will follow should favourable space weather
activity eventuate.

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