Viewing archive of Thursday, 5 April 2001

Solar activity report

Report of Solar-Geophysical Activity 2001 Apr 05 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 095 Issued at 2200Z on 05 Apr 2001

IA. Analysis of Solar Active Regions and Activity from 04-2100Z to 05-2100Z

Solar activity was high. Two major flares were observed during the past 24 hours. The first was a long-duration M8 that peaked at 0922Z, originating from Region 9393 behind the west limb. This flare was associated with a CME which gives every indication of moving in a westward direction, perpendicular to the Earth-Sun line. The second was an M5/2n at 1725Z from Region 9415 (S21E47). This event had an extended maximum and a slow decay profile. An associated CME was just entering the C2 field of view at forecast issue time and did not appear to have any earthward component. Region 9415 appears to have formed a delta configuration in the leader portion of the group. Region 9417 (S08E27) grew rapidly during the last 24 hours and produced an M1/Sn flare at 0834Z. Today's 10.7 cm background flux of 210 SFU had to be estimated due to greatly enhanced radio noise levels occurring with today's long-duration flare activity.
IB. Solar Activity Forecast
Solar activity is expected to be mostly moderate during the next three days. There is a fair chance, however, for additional major flares from Region 9415.
IIA. Geophysical Activity Summary 04-2100Z to 05-2100Z
The geomagnetic field was predominantly quiet to active during the past 24 hours. The first nine hours of the period were quiet, but activity increased to mostly active from 0600-2100Z. There was a minor storm period at high latitudes from 0900-1200Z. The greater than 10 MeV proton event continues in progress with a continued slow decline in flux levels. The flux at 05/2100Z was 25 pfu.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be mostly unsettled tomorrow, with a chance for some isolated active periods. Predominantly unsettled levels should prevail for the second and third days.
III. Event Probabilities 06 Apr to 08 Apr
Class M75%75%75%
Class X20%20%20%
PCAFin progress
IV. Penticton 10.7 cm Flux
  Observed       05 Apr 210
  Predicted   06 Apr-08 Apr  210/210/205
  90 Day Mean        05 Apr 167
V. Geomagnetic A Indices
  Observed Afr/Ap 04 Apr  012/015
  Estimated     Afr/Ap 05 Apr  015/015
  Predicted    Afr/Ap 06 Apr-08 Apr  015/015-012/008-012/008
VI. Geomagnetic Activity Probabilities 06 Apr to 08 Apr
A. Middle Latitudes
Minor storm15%10%10%
Major-severe storm10%05%05%
B. High Latitudes
Minor storm20%15%10%
Major-severe storm15%10%10%

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