Viewing archive of Thursday, 26 May 2011

Solar activity report

Report of Solar-Geophysical Activity 2011 May 26 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 146 Issued at 2200Z on 26 May 2011

IA. Analysis of Solar Active Regions and Activity from 25-2100Z to 26-2100Z

Solar activity was low. A fast emerging flux region was numbered today as Region 1223 (S15E14). This region produced two C-class events as it evolved. The first was a C1 at 25/2103Z then followed by a second C1 at 25/2158Z. It is configured as a Cso group with a beta magnetic classification.
IB. Solar Activity Forecast
Solar activity is expected to be very low to low with a chance for a C-class event.
IIA. Geophysical Activity Summary 25-2100Z to 26-2100Z
The geomagnetic field was mainly quiet with an active period reported at 25/1800Z at mid-latitudes. Observations from the ACE spacecraft indicated a possible co-rotating interaction region (CIR) at around 25/1330Z. Solar wind speed increased from around 340 to 390 km/s and density jumped to 6 p/cc. Interplanetary magnetic field changes included an increase in Bt to +7 nT, while Bz dipped to -6 nT.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be mostly unsettled with isolated active periods, and isolated minor storms possible at high-latitudes, for the next three days (27-29 May). Activity is expected due to a recurrent coronal hole high speed stream. In addition, a disappearing filament observed at 25/0801Z may possibly disturb the field on day two (28 May).
III. Event Probabilities 27 May to 29 May
Class M01%01%01%
Class X01%01%01%
IV. Penticton 10.7 cm Flux
  Observed       26 May 083
  Predicted   27 May-29 May  085/085/085
  90 Day Mean        26 May 108
V. Geomagnetic A Indices
  Observed Afr/Ap 25 May  002/004
  Estimated     Afr/Ap 26 May  005/007
  Predicted    Afr/Ap 27 May-29 May  010/010-015/015-010/012
VI. Geomagnetic Activity Probabilities 27 May to 29 May
A. Middle Latitudes
Minor storm05%10%05%
Major-severe storm01%05%01%
B. High Latitudes
Minor storm10%15%10%
Major-severe storm05%05%05%

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