Viewing archive of Wednesday, 26 December 2001

Solar activity report

Any mentioned solar flare in this report has a scaling factor applied by the Space Weather Prediction Center (SWPC). Because of the SWPC scaling factor, solar flares are reported as 42% smaller than for the science quality data. The scaling factor has been removed from our archived solar flare data to reflect the true physical units.
Report of Solar-Geophysical Activity 2001 Dec 26 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 360 Issued at 2200Z on 26 Dec 2001

IA. Analysis of Solar Active Regions and Activity from 25-2100Z to 26-2100Z

Solar activity was high. Region 9742 (N12W68) produced an M7/1b proton flare at 26/0540 UTC. The flare was associated with strong type II/IV sweeps and a 2600 sfu burst at 2695 MHz. This Region also produced several other flares this past day including an M1/1f at 26/1226 UTC and an M1/Sf at 26/1718 UTC. Small flares also occurred in Regions 9748 (S10W48), 9751 (N04E04), and 9754 (S09E24). Several small new regions were numbered -- 9756 (S28E72), 9757 (S09E02), 9758 (N13E20), 9759 (N17E28), 9760 (N06E35), and 9761 (N09E75).
IB. Solar Activity Forecast
Solar activity is expected to be moderate to high. Another major flare is possible in Region 9742. M-class flares are also possible in Regions 9748, 9751, and 9754.
IIA. Geophysical Activity Summary 25-2100Z to 26-2100Z
The geomagnetic field was quiet to unsettled. Greater than 100 MeV and 10 MeV proton events occurred in association with the major flare discussed in part IA. The greater than 100 MeV event started at 26/0555 UTC, reached a peak of 50 pfu at 26/0720 UTC, and dropped below the 1 pfu event threshold at 26/1920 UTC. The greater than 10 MeV event started at 26/0605 UTC, reached a peak of 779 pfu at 26/1115 UTC, and continues in progress (current flux about 115 pfu). This particle event was also associated with a GLE starting at about 26/0600 UTC and reaching a maximum at about 26/0620 UTC (8% at Apatity, Oulu, and McMurdo, and 2% at Moscow). A Polar Cap Absorption event (PCA) also occurred, reaching a peak absorption of about 9 dB at 26/1115 UTC and continuing in progress at this writing.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be quiet to unsettled until the Earth encounters the CME associated with today's major flare. Active to storm conditions are expected to begin on 28 or 29 December. The bulk of the CME appeared to be directed to the west which increases the uncertainty of the begin time and eventual impact to the geomagnetic field.
III. Event Probabilities 27 Dec to 29 Dec
Class M80%80%80%
Class X10%10%10%
PCAFin progress
IV. Penticton 10.7 cm Flux
  Observed       26 Dec 268
  Predicted   27 Dec-29 Dec  265/260/255
  90 Day Mean        26 Dec 217
V. Geomagnetic A Indices
  Observed Afr/Ap 25 Dec  011/008
  Estimated     Afr/Ap 26 Dec  008/006
  Predicted    Afr/Ap 27 Dec-29 Dec  008/008-030/012-015/020
VI. Geomagnetic Activity Probabilities 27 Dec to 29 Dec
A. Middle Latitudes
Minor storm05%25%10%
Major-severe storm05%10%10%
B. High Latitudes
Minor storm10%30%20%
Major-severe storm05%15%10%

All times in UTC

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