Viewing archive of Monday, 22 October 2001

Solar activity report

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

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 295 Issued at 2200Z on 22 Oct 2001

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

Solar activity was at high levels. Region 9672 (S18E13) produced an X1/2b flare at 22/1759 UTC and an associated Type II radio sweep with a shock velocity estimated at 1043 km/s. More than 20 twenty percent umbral coverage of large asymmetrical spot was observed in H-alpha. Shortly before this flare, Region 9672 had produced an M6/2n at 22/1508 UTC which had also produced a Type II and IV radio sweep (shock velocity estimated at 955 km/sec). Region 9672 had formed a strong delta configuration earlier in period. LASCO/EIT imagery has not updated sufficiently, to be able to ascertain, if a CME was created from either of these flares. Region 9658 (rotated of west limb at S15) produced an M1/Sf at 22/0040 UTC before exiting the visible disk. New Region 9677 (N20E48) was numbered today.
IB. Solar Activity Forecast
Solar activity is expected to be at moderate to high levels. Region 9672 remains capable of producing further M-class or isolated major flares.
IIA. Geophysical Activity Summary 21-2100Z to 22-2100Z
The geomagnetic field was at minor to major storm levels. The second CME passage that had been expected today appears to have been incorporated into the first, creating minor to major storm conditions for the entire period aside from a couple isolated severe storm conditions at high latitudes. The estimated Afr (based on Boulder magnetometer) reading reached 59 and USAF planetary reached 75. The greater than 10 MeV proton flux at geosynchronous orbit exceeded threshold at 22/1910 UTC. At the time of issue of this bulletin the 10 MeV proton flux was at 17 pfu.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to remain at active to major storm levels through the first part of day one. The field should return to quiet to active conditions at the end of days one and two. Day three should see minor to isolated major storm conditions return due a potential CME passage from activity seen in Region 9672 on 22 October. Protons are expected to remain above 10 MeV through the first day of period.
III. Event Probabilities 23 Oct to 25 Oct
Class M 80%80%75%
Class X 40%40%30%
IV. Penticton 10.7 cm Flux
  Observed       22 Oct 233
  Predicted    23 Oct-25 Oct  230/220/220
  90 Day Mean        22 Oct 192
V. Geomagnetic A Indices
  Observed Afr/Ap 21 Oct  029/040
  Estimated     Afr/Ap 22 Oct  045/075
  Predicted     Afr/Ap 23 Oct-25 Oct  015/030-015/015-020/030
VI. Geomagnetic Activity Probabilities 23 Oct to 25 Oct
A. Middle Latitudes
Minor storm 20%15%30%
Major-severe storm 01%05%10%
B. High Latitudes
Minor storm 30%20%40%
Major-severe storm 10%05%15%

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