Report of Solar Geophysical Activity
Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 271 Issued at 2200Z on 28 Sep 2015 IA. Analysis of Solar Active Regions and Activity from 27/2100Z to 28/2100Z: Solar activity has been at high levels for the past 24 hours. The largest solar event of the period was a M7 event observed at 28/1458Z from Region 2422 (S20W30). There are currently 6 numbered sunspot regions on the disk. IB. Solar Activity Forecast: Solar activity is likely to be moderate with a chance for X-class flares on days one, two, and three (29 Sep, 30 Sep, 01 Oct). IIA. Geophysical Activity Summary 27/2100Z to 28/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed, as measured by the ACE spacecraft, reached a peak speed of 410 km/s at 28/0018Z. Total IMF reached 5 nT at 28/1140Z. The maximum southward component of Bz reached -4 nT at 28/0043Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 408 pfu. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet levels on day one (29 Sep) and quiet to unsettled levels on days two and three (30 Sep, 01 Oct). Protons have a chance of crossing threshold on days one and two (29 Sep, 30 Sep) and have a slight chance of crossing threshold on day three (01 Oct). III. Event probabilities 29 Sep-01 Oct Class M 70/70/70 Class X 25/25/25 Proton 25/25/20 PCAF green IV. Penticton 10.7 cm Flux Observed 28 Sep 124 Predicted 29 Sep-01 Oct 130/125/125 90 Day Mean 28 Sep 105 V. Geomagnetic A Indices Observed Afr/Ap 27 Sep 004/004 Estimated Afr/Ap 28 Sep 003/004 Predicted Afr/Ap 29 Sep-01 Oct 006/005-006/006-008/009 VI. Geomagnetic Activity Probabilities 29 Sep-01 Oct A. Middle Latitudes Active 05/10/15 Minor Storm 01/05/05 Major-severe storm 01/01/01 B. High Latitudes Active 15/20/20 Minor Storm 15/25/25 Major-severe storm 10/15/20 Radio Events Observed 28 Sep 2015 A. 245 MHz Bursts Start End Peak Flux Time of Peak Duration 0013 0013 190 0013 0000 0352 0353 270 0352 0001 0530 0530 3300 0530 0000 1126 1126 100 1126 0000 1535 1535 100 1535 0000 B. 245 MHz Noise Storms Start End Peak Flux Time of Peak 0544 1442 410 0907 www.swpc.noaa.gov/phenomena/solar-radiation-storm
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