[ips-sf] IPS Summary Forecast for 21 September - issued 2353UT/20-Sep-2013

[rwc]

The sunspot number and background solar UV and X-ray flux are trending
upwards. Active Region 1850 has been very busy producing two B-class
and four C-class X-ray flares during the previous 24 hours. The
largest event was a C3.8 event at 11:53 UT. Solar activity is expected
to remain low though with a chance of an M-class flare. There is a
spectacular hedgerow prominence on the north east limb well worth
observing using a telescope with H-alpha blocking filter. SOHO
spacecraft images show impressive Coronal Mass Ejections (CMEs)
leaving the north-north east limb starting about 03 UT followed by a
second event at 13 UT on 20 September. These CMEs are not Earthward
directed. There is a large coronal hole (CH 587) located in the
Northern Hemisphere and a high speed solar wind stream emanating from
this region is expected to sweep past Earth 22-23 September. The solar
wind speed declined from 550 km/s to less than 450 km/s during the
previous 24 hours and is expected to abate further today. Geomagnetic
conditions are expected to be quiet during the next two days, 21-22
September, and then become quiet to unsettled again during 22-23
September due to weak CME effects and the arrival of the next high
speed stream. HF propagation conditions for Australian mid-latitude
locations were depressed during 20 September and are expected to
return to near predicted monthly values during 21-22 September.

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