Viewing archive of Sunday, 22 April 2001

Solar activity report

Report of Solar-Geophysical Activity 2001 Apr 22 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 112 Issued at 2200Z on 22 Apr 2001

IA. Analysis of Solar Active Regions and Activity from 21-2100Z to 22-2100Z

Solar activity was moderate due to an M3/1N flare at 22/2044 UTC in Region 9433 (N17E26). The flare was associated with a tenflare of 270 sfu and a weak type II sweep. This Region remains a large F-type sunspot group with mixed spot polarities. Spot growth has resulted in the formation of at least two small delta configurations in the central and leading sunspots.
IB. Solar Activity Forecast
Solar activity is expected to be moderate. Additional M-class flares are likely in Region 9433. The possibility of a major flare is increasing as sunspot growth and magnetic complexity develops.
IIA. Geophysical Activity Summary 21-2100Z to 22-2100Z
The geomagnetic field ranged from quiet to minor storm levels. This activity is most likely related to the passage of one of the CMEs observed over the northwest limb earlier this week.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be at active to minor storm levels becoming unsettled to active within the next 24 hours. There is a chance of an energetic proton event if a major flare occurs in Region 9433.
III. Event Probabilities 23 Apr to 25 Apr
Class M75%75%75%
Class X10%10%10%
IV. Penticton 10.7 cm Flux
  Observed       22 Apr 193
  Predicted   23 Apr-25 Apr  205/210/210
  90 Day Mean        22 Apr 166
V. Geomagnetic A Indices
  Observed Afr/Ap 21 Apr  007/007
  Estimated     Afr/Ap 22 Apr  030/030
  Predicted    Afr/Ap 23 Apr-25 Apr  015/010-010/010-010/010
VI. Geomagnetic Activity Probabilities 23 Apr to 25 Apr
A. Middle Latitudes
Minor storm10%05%05%
Major-severe storm05%01%01%
B. High Latitudes
Minor storm20%10%05%
Major-severe storm10%05%01%

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