NOAA/USAF Report of Solar-Geophysical Activity 25 November 2000
:Product: Report of Solar-Geophysical Activity :Issued: 2000 Nov 25 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 330 Issued at 2200Z on 25 Nov 2000 IA. Analysis of Solar Active Regions and Activity from 24/2100Z to 25/2100Z: Solar activity continued at high levels. The period began with another X-class flare from Region 9236 (N22W20). The X1/2n flare occurred at 24/2159Z and had associated minor centimetric radio bursts and a CME. Reports of strong doppler shifts in the NE-SW filament in Region 9240 (N08E34) were soon followed by an impressive eruption at 25/0131Z. The eruption included an M8/2N, long duration ribbon flare with strong radio bursts including a 14000 sfu Tenflare. Strong Type II and IV sweeps also occurred with this flare and a CME was observed on LASCO imagery. Region 9236 flared again, producing an M3/2n flare and CME at 25/0920Z. The period ended with an X1/2b from Region 9236 with moderate to strong radio bursts and Type II sweep (910km/s). It appears that yet another Earth-directed CME was associated with this event. No significant new growth was noted in Region 9236 over the past 18 hours, but it continues to produce frequent flares in a complex, beta-gamma configuration exceeding 600 millionths of white light coverage. IB. Solar Activity Forecast: Solar activity is expected to continue at moderate to high levels. Region 9236 is capable of continued M and X-class events. A filament has reformed in the vicinity of the 0131Z eruption in Region 9240. If the present pattern continues, we should see another major event from this region in the next three days. IIA. Geophysical Activity Summary 24/2100Z to 25/2100Z: The geomagnetic field was quiet to unsettled with isolated active periods at high latitudes. The greater than 10 MeV proton event that began at 24/1520Z is still in progress and is currently ranging 12 to 18 pfu. The maximum so far was 93 pfu at 24/1920Z. The greater than 100 MeV proton event that began at 24/1720Z, ended at 24/1820Z with a peak flux of 1.1 pfu at 24/1810Z. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to reach minor to major storm levels early in day one. We observed as many as six Earth directed CME'S in the last 48 hours, so minor to major storm levels are expected through the next three days. Another proton event is possible should Regions 9236 or 9240 produce another major flare. III. Event Probabilities 26 Nov-28 Nov Class M 75/70/60 Class X 50/40/35 Proton 80/50/40 PCAF yellow IV. Penticton 10.7 cm Flux Observed 25 Nov 202 Predicted 26 Nov-28 Nov 200/195/195 90 Day Mean 25 Nov 175 V. Geomagnetic A Indices Observed Afr/Ap 24 Nov 009/009 Estimated Afr/Ap 25 Nov 010/012 Predicted Afr/Ap 26 Nov-28 Nov 060/070-050/060-030/040 VI. Geomagnetic Activity Probabilities 26 Nov-28 Nov A. Middle Latitudes Active 20/20/50 Minor storm 40/40/30 Major-severe storm 40/40/20 B. High Latitudes Active 20/20/40 Minor storm 30/30/30 Major-severe storm 50/50/30
