Viewing archive of Wednesday, 25 May 2011

Solar activity report

Report of Solar-Geophysical Activity 2011 May 25 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 145 Issued at 2200Z on 25 May 2011

IA. Analysis of Solar Active Regions and Activity from 24-2100Z to 25-2100Z

Solar activity was very low. Only low level B-class events were observed during the period. Region 1220 (N12, L=249) produced a long duration B2 event at 24/2237Z prior to its rotation around the west limb. Region 1218 (S16W28) also produced B-class events with frequent point brightenings within the region. This region remains a spotless plage. A nine degree filament located at N44E37 disappeared between 25/0801-1256Z. A further analysis of this event will be performed as image data updates for any associated CME activity. New Region 1222 (N15W24) was numbered today.
IB. Solar Activity Forecast
Solar activity is expected to be very low.
IIA. Geophysical Activity Summary 24-2100Z to 25-2100Z
The geomagnetic field was quiet. Solar wind speeds observed by the ACE spacecraft have averaged around 380 km/s through the period with occasional minor fluctuations in the IMF Bz between -4/+5 nT.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be mostly quiet on day one (26 May). Quiet to unsettled conditions, with isolated active levels, are expected for days two and three (27-28 May) as a recurrent coronal hole high speed stream becomes geo-effective.
III. Event Probabilities 26 May to 28 May
Class M01%01%01%
Class X01%01%01%
IV. Penticton 10.7 cm Flux
  Observed       25 May 080
  Predicted   26 May-28 May  080/080/080
  90 Day Mean        25 May 108
V. Geomagnetic A Indices
  Observed Afr/Ap 24 May  005/006
  Estimated     Afr/Ap 25 May  003/005
  Predicted    Afr/Ap 26 May-28 May  005/008-010/012-015/015
VI. Geomagnetic Activity Probabilities 26 May to 28 May
A. Middle Latitudes
Minor storm01%05%10%
Major-severe storm01%01%05%
B. High Latitudes
Minor storm05%10%15%
Major-severe storm01%05%05%

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