Viewing archive of Thursday, 28 July 2005

Solar activity report

Report of Solar-Geophysical Activity 2005 Jul 28 2204 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 209 Issued at 2200Z on 28 Jul 2005

IA. Analysis of Solar Active Regions and Activity from 27-2100Z to 28-2100Z

Solar activity was moderate due to an M1 x-ray event at 0030 UTC from newly numbered Region 792 (N12E78). The event was associated with a CME off the east limb with a plane of sky speed of about 850 km/s. Region 792 is clearly the return of old Region 786, and is likely to have been the source of the recent series of CME's originating behind the east limb. The region was also responsible for the remainder of today's occasional C-class and B-class activity. Region 791 (N14W20), the only other spotted group on the Sun, was quiet and stable.
IB. Solar Activity Forecast
Solar activity is expected to moderate with Region 792 as the dominant source of activity. There is also a slight chance for major flare activity from this group.
IIA. Geophysical Activity Summary 27-2100Z to 28-2100Z
The geomagnetic field was mostly unsettled to active with a minor storm period from 0300-0600 UTC. Solar wind data indicate the onset of a co-rotating interaction region late on the 27th followed by the onset of coronal hole stream by about midday on the 28th. Solar wind speed is currently steady at around 600 km/s. A greater than 10 MeV proton event began at 2300 UTC on the 27th and reached a maximum so far of 32 PFU at 1300 UTC on the 28th. The event continues in progress with a flux of 27 PFU at the end of the analysis interval. The main source for this event appears the shock driven by the fast CME of 27/0454 UTC. It should be noted, however, the flux levels were already enhanced prior to this event. This initial enhancement may have been caused by one or more of the earlier CME's that originated behind the east limb; for example the CME's of 26/0930 UTC, 25/1106 UTC, and 24/1418 UTC.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be mostly unsettled with a chance for some active periods for 29 July. Conditions are expected to decline to predominantly unsettled for 30 July and should be quiet to unsettled for 31 July. The greater than 10 MeV proton event is expected to end sometime on 29 July, provided that no new particles are accelerated by new activity from Region 792.
III. Event Probabilities 29 Jul to 31 Jul
Class M70%70%70%
Class X10%10%10%
Proton90%10%10%
PCAFYellow
IV. Penticton 10.7 cm Flux
  Observed       28 Jul 096
  Predicted   29 Jul-31 Jul  105/110/115
  90 Day Mean        28 Jul 096
V. Geomagnetic A Indices
  Observed Afr/Ap 27 Jul  015/017
  Estimated     Afr/Ap 28 Jul  016/030
  Predicted    Afr/Ap 29 Jul-31 Jul  010/015-010/012-007/010
VI. Geomagnetic Activity Probabilities 29 Jul to 31 Jul
A. Middle Latitudes
Active35%30%25%
Minor storm20%20%15%
Major-severe storm05%05%05%
B. High Latitudes
Active30%30%25%
Minor storm25%25%15%
Major-severe storm10%10%05%

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