Viewing archive of Monday, 23 April 2001

Solar activity report

Report of Solar-Geophysical Activity 2001 Apr 23 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 113 Issued at 2200Z on 23 Apr 2001

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

Solar activity has been moderate. Region 9433 (N17E14) produced two M-class events during the period, an M1/1f flare at 23/0128 UTC and an M4/2n at 23/2030 UTC. Region 9431 (S11W29) produced an C2/Sf at 23/1223 UTC with an associated 6 degree long disappearing filament. Region 9433 continues to grow in spot count and area. This region has retained its F-type sunspot group with mixed polarities and a delta configuration.
IB. Solar Activity Forecast
Solar activity is expected to be moderate. Region 9433 is likely to continue to produce M-class events with the chance for an isolated major flare during the next three days.
IIA. Geophysical Activity Summary 22-2100Z to 23-2100Z
The geomagnetic field has been at quiet to minor storm conditions for the last 24 hours.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be quiet to unsettled. There remains a chance for an energetic proton event if a major flare occurs in Region 9433.
III. Event Probabilities 24 Apr to 26 Apr
Class M75%75%75%
Class X10%10%10%
IV. Penticton 10.7 cm Flux
  Observed       23 Apr 196
  Predicted   24 Apr-26 Apr  205/210/210
  90 Day Mean        23 Apr 166
V. Geomagnetic A Indices
  Observed Afr/Ap 22 Apr  017/028
  Estimated     Afr/Ap 23 Apr  020/025
  Predicted    Afr/Ap 24 Apr-26 Apr  010/010-010/010-010/015
VI. Geomagnetic Activity Probabilities 24 Apr to 26 Apr
A. Middle Latitudes
Minor storm05%05%05%
Major-severe storm01%01%01%
B. High Latitudes
Minor storm10%10%10%
Major-severe storm05%05%05%

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