NOAA SEC Report of Solar-Geophysical Activity 13 Sep 2001
:Product: Report of Solar-Geophysical Activity :Issued: 2001 Sep 13 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 256 Issued at 2200Z on 13 Sep 2001 IA. Analysis of Solar Active Regions and Activity from 12/2100Z to 13/2100Z: Solar activity has been low, however there have been several C-class flares with associated Type II radio sweeps indicating potential CME activity. The largest event was a C9.6 x-ray flare at 12/2149 UTC. This event appeared to originate from Region 9606 (S17W79), per test imagery available from the GOES-12 SXI instrument, and was accompanied by a Type II sweep with estimated velocity of 747 km/s. Two additional impulsive events were also observed: A C7/Sn flare at 13/1602 UTC from Region 9610 (S13W18), with associated Type II sweep estimated velocity of 596 km/s, and, again per SXI imagery, a C5.8 x-ray event at 13/1951 UTC from Region 9607 (S16W51), with associated Type II sweep velocity of 771 km/s. Other C-class flare activity occurred in Regions 9616 (S10E55) and 9608 (S25W33). Two new regions were numbered today: 9618 (S21W26) and 9619 (N17E21). IB. Solar Activity Forecast: Solar activity is expected to be moderate to high. Region 9608 remains very large in areal coverage and spot count, with appreciable magnetic complexity, and remains capable of producing a major flare. Regions 9610 and 9616 are also potential sources of M-class activity. IIA. Geophysical Activity Summary 12/2100Z to 13/2100Z: The geomagnetic field was quiet to active. There were some indications in the ACE satellite data of a weak interplanetary shock passage at about 13/0100 UTC. Active geomagnetic conditions and an isolated period of minor storming at higher latitudes followed, and persisted for several hours until mainly unsettled conditions developed from about 13/1200 UTC onward. This disturbance is presumed to have originated from the CME activity of 9 September. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be quiet to active for the next three days. Shock passages are expected from the DSF activity of 11 September, and the CME activity of the past two days, over the course of the forecast period. Isolated periods of minor storming at higher latitudes are possible. III. Event Probabilities 14 Sep-16 Sep Class M 70/70/70 Class X 10/10/10 Proton 10/10/10 PCAF yellow IV. Penticton 10.7 cm Flux Observed 13 Sep 240 Predicted 14 Sep-16 Sep 235/225/225 90 Day Mean 13 Sep 164 V. Geomagnetic A Indices Observed Afr/Ap 12 Sep 009/013 Estimated Afr/Ap 13 Sep 015/015 Predicted Afr/Ap 14 Sep-16 Sep 018/020-015/015-015/015 VI. Geomagnetic Activity Probabilities 14 Sep-16 Sep A. Middle Latitudes Active 25/20/20 Minor storm 15/15/15 Major-severe storm 05/05/05 B. High Latitudes Active 30/25/25 Minor storm 20/15/15 Major-severe storm 05/05/05
