:Product: 0316RSGA.txt :Issued: 2013 Mar 16 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 75 Issued at 2200Z on 16 Mar 2013 IA. Analysis of Solar Active Regions and Activity from 15/2100Z to 16/2100Z: 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 16/0539Z from Region 1698 (S19W57). There are currently 6 numbered sunspot regions on the disk. IB. Solar Activity Forecast: Solar activity is expected to be low with a slight chance for an M-class flare on days one, two, and three (17 Mar, 18 Mar, 19 Mar). IIA. Geophysical Activity Summary 15/2100Z to 16/2100Z: 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 551 km/s at 16/0506Z. Total IMF reached 7 nT at 16/0257Z. The maximum southward component of Bz reached -6 nT at 16/0309Z. Protons greater than 10 MeV at geosynchronous orbit reached a peak level of 12 pfu at 16/2015Z. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at unsettled to major storm levels on day one (17 Mar), quiet to active levels on day two (18 Mar) and quiet levels on day three (19 Mar). Protons are expected to cross threshold on day one (17 Mar), are likely to cross threshold on day two (18 Mar) and have a chance of crossing threshold on day three (19 Mar). III. Event probabilities 17 Mar-19 Mar Class M 20/20/20 Class X 01/01/01 Proton 75/60/25 PCAF yellow IV. Penticton 10.7 cm Flux Observed 16 Mar 126 Predicted 17 Mar-19 Mar 125/120/115 90 Day Mean 16 Mar 116 V. Geomagnetic A Indices Observed Afr/Ap 15 Mar 005/005 Estimated Afr/Ap 16 Mar 012/015 Predicted Afr/Ap 17 Mar-19 Mar 028/039-014/020-006/005 VI. Geomagnetic Activity Probabilities 17 Mar-19 Mar A. Middle Latitudes Active 30/30/05 Minor Storm 35/10/01 Major-severe storm 20/01/01 B. High Latitudes Active 05/15/15 Minor Storm 20/30/10 Major-severe storm 70/40/05