Viewing archive of Wednesday, 23 May 2012

Solar activity report

Report of Solar-Geophysical Activity 2012 May 23 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 144 Issued at 2200Z on 23 May 2012

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

Solar activity was low. Region 1484 (N11W56) produced a C1/Sf flare at 23/0027Z. Region 1484 decayed slightly in its leader and intermediate spots. Slight growth was observed in Region 1483 (S24W79) as it approached the west limb. New Region 1489 (S30E40) was numbered today. The rest of the spotted regions showed no significant changes. No earth directed CMEs were observed during the reporting period.
IB. Solar Activity Forecast
Solar activity is expected to be very low to low with a slight chance for an M-class flare for the forecast period (24 - 26 May).
IIA. Geophysical Activity Summary 22-2100Z to 23-2100Z
The geomagnetic field ranged from quiet to minor storming. Early on 23 May, solar wind speed at the ACE spacecraft increased from approximately 430 km/s to 630 km/s while the interplanetary magnetic field (IMF) fluctuated between +/- 10 nT. The geomagnetic field responded with active to minor storm periods between 23/0000 - 0900Z. By about 23/0600Z, total field strength decreased to approximately 4 - 5 nT while the Bz component remained mostly positive. Solar wind speed remained fairly steady around 580 km/s to 600 km/s through the end of the reporting period.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be quiet to unsettled with a chance for further active periods on day 1 (24 May). Mostly quiet conditions are expected on day 2 (25 May). On day 3 (26 May), quiet to unsettled conditions are expected with a chance for isolated active periods around mid-day as a glancing blow from the 22 May CME is possible.
III. Event Probabilities 24 May to 26 May
Class M10%10%10%
Class X01%01%01%
IV. Penticton 10.7 cm Flux
  Observed       23 May 117
  Predicted   24 May-26 May  115/115/110
  90 Day Mean        23 May 116
V. Geomagnetic A Indices
  Observed Afr/Ap 22 May  015/018
  Estimated     Afr/Ap 23 May  012/018
  Predicted    Afr/Ap 24 May-26 May  010/010-005/005-008/008
VI. Geomagnetic Activity Probabilities 24 May to 26 May
A. Middle Latitudes
Minor storm15%01%10%
Major-severe storm05%01%01%
B. High Latitudes
Minor storm20%05%15%
Major-severe storm05%01%05%

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