:Product: 0417RSGA.txt :Issued: 2015 Apr 17 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 107 Issued at 2200Z on 17 Apr 2015 IA. Analysis of Solar Active Regions and Activity from 16/2100Z to 17/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C2 event observed at 17/0137Z from Region 2325 (N04E32). There are currently 5 numbered sunspot regions on the disk. IB. Solar Activity Forecast: Solar activity is expected to be low with a chance for M-class flares and a slight chance for an X-class flare on days one, two, and three (18 Apr, 19 Apr, 20 Apr). IIA. Geophysical Activity Summary 16/2100Z to 17/2100Z: The geomagnetic field has been at quiet to major storm levels for the past 24 hours. Solar wind speed, as measured by the ACE spacecraft, reached a peak speed of 784 km/s at 17/0408Z. Total IMF reached 9 nT at 16/2105Z. The maximum southward component of Bz reached -8 nT at 16/2105Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 2087 pfu. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on days one and three (18 Apr, 20 Apr) and quiet to unsettled levels on day two (19 Apr). III. Event probabilities 18 Apr-20 Apr Class M 40/40/40 Class X 10/10/10 Proton 01/01/01 PCAF green IV. Penticton 10.7 cm Flux Observed 17 Apr 150 Predicted 18 Apr-20 Apr 155/155/155 90 Day Mean 17 Apr 129 V. Geomagnetic A Indices Observed Afr/Ap 16 Apr 028/038 Estimated Afr/Ap 17 Apr 025/028 Predicted Afr/Ap 18 Apr-20 Apr 012/015-007/008-010/012 VI. Geomagnetic Activity Probabilities 18 Apr-20 Apr A. Middle Latitudes Active 30/20/30 Minor Storm 10/05/05 Major-severe storm 01/01/01 B. High Latitudes Active 15/15/15 Minor Storm 30/30/30 Major-severe storm 40/25/35