Viewing archive of Thursday, 23 May 2013

Solar activity report

Report of Solar-Geophysical Activity 2013 May 23 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 143 Issued at 2200Z on 23 May 2013

IA. Analysis of Solar Active Regions and Activity from 22-2100Z to 23-2100Z

Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C3 event observed at 23/1450Z from Region 1756 (S20E27). There are currently 7 numbered sunspot regions on the disk.
IB. Solar Activity Forecast
Solar activity is expected to be low with a chance for M-class flares and a slight chance for an X-class flare on days one, two, and three (24 May, 25 May, 26 May).
IIA. Geophysical Activity Summary 22-2100Z to 23-2100Z
The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed, as measured by the ACE spacecraft, reached a peak speed of 475 km/s at 23/1933Z, however ACE/SWEPAM data became suspect due to proton contamination from the 22 May M5 flare. Total IMF reached 8 nT at 23/1656Z. The maximum southward component of Bz reached -4 nT at 23/0949Z. Protons greater than 10 MeV at geosynchronous orbit reached a peak level of 1660 pfu at 23/0650Z. Protons greater than 100 MeV at geosynchronous orbit reached a peak level of 2 pfu at 22/2105Z and the event ended at 23/0745Z. Electrons greater than 2 MeV at geosynchronous orbit were also suspect due to proton contamination.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be at quiet to minor storm levels on day one (24 May), quiet to active levels on day two (25 May) and quiet to unsettled levels on day three (26 May). Protons are expected to remain above threshold on day one (24 May), are likely to cross threshold on day two (25 May) and have a chance of crossing threshold on day three (26 May).
III. Event Probabilities 24 May to 26 May
Class M45%45%45%
Class X15%15%15%
IV. Penticton 10.7 cm Flux
  Observed       23 May 135
  Predicted   24 May-26 May 135/135/130
  90 Day Mean        23 May 122

V. Geomagnetic A Indices
  Observed Afr/Ap 22 May  010/012
  Estimated     Afr/Ap 23 May  008/008
  Predicted    Afr/Ap 24 May-26 May  011/015-014/020-008/012

VI. Geomagnetic Activity Probabilities 24 May to 26 May
A. Middle Latitudes
Minor storm20%15%05%
Major-severe storm05%05%01%
B. High Latitudes
Minor storm25%30%25%
Major-severe storm55%50%25%

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