NOAA SEC Report of Solar-Geophysical Activity 26 Dec 2001
:Product: Report of Solar-Geophysical Activity :Issued: 2001 Dec 26 2200 UT # Prepared jointly by the U.S. Dept. of Commerce, NOAA, #Space Environment Center and the U.S. Air Force. # 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-29 Dec Class M 80/80/80 Class X 10/10/10 Proton 99/75/25 PCAF in 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-29 Dec A. Middle Latitudes Active 15/50/30 Minor storm 05/25/10 Major-severe storm 05/10/10 B. High Latitudes Active 20/50/50 Minor storm 10/30/20 Major-severe storm 05/15/10
