:Product: 0918RSGA.txt :Issued: 2015 Sep 18 2200 UTC # Prepared jointly by the U.S. Dept. of Commerce, NOAA, # Space Weather Prediction Center and the U.S. Air Force. # Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 261 Issued at 2200Z on 18 Sep 2015 IA. Analysis of Solar Active Regions and Activity from 17/2100Z to 18/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C6 event observed at 17/2115Z from Region 2415 (S20W16). There are currently 3 numbered sunspot regions on the disk. IB. Solar Activity Forecast: Solar activity is expected to be low with a chance for M-class flares on days one, two, and three (19 Sep, 20 Sep, 21 Sep). IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed, as measured by the ACE spacecraft, reached a peak speed of 465 km/s at 18/1544Z. Total IMF reached 7 nT at 18/1209Z. The maximum southward component of Bz reached -6 nT at 18/1149Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 3502 pfu. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on day one (19 Sep), unsettled to minor storm levels on day two (20 Sep) and active to minor storm levels on day three (21 Sep). III. Event probabilities 19 Sep-21 Sep Class M 25/25/25 Class X 05/05/05 Proton 05/05/05 PCAF green IV. Penticton 10.7 cm Flux Observed 18 Sep 103 Predicted 19 Sep-21 Sep 105/110/110 90 Day Mean 18 Sep 104 V. Geomagnetic A Indices Observed Afr/Ap 17 Sep 012/011 Estimated Afr/Ap 18 Sep 010/011 Predicted Afr/Ap 19 Sep-21 Sep 014/016-018/025-021/030 VI. Geomagnetic Activity Probabilities 19 Sep-21 Sep A. Middle Latitudes Active 30/40/40 Minor Storm 10/20/20 Major-severe storm 01/01/01 B. High Latitudes Active 15/10/10 Minor Storm 30/30/30 Major-severe storm 35/50/50