:Product: 0520RSGA.txt :Issued: 2013 May 20 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 140 Issued at 2200Z on 20 May 2013 IA. Analysis of Solar Active Regions and Activity from 19/2100Z to 20/2100Z: Solar activity has been at moderate levels for the past 24 hours. The largest solar event of the period was a M1 event observed at 20/0525Z. There are currently 7 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 (21 May, 22 May, 23 May). IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z: The geomagnetic field has been at quiet to active levels for the past 24 hours. Solar wind speed, as measured by the ACE spacecraft, reached a peak speed of 493 km/s at 19/2257Z. Total IMF reached 14 nT at 19/2256Z. The maximum southward component of Bz reached -5 nT at 20/1953Z. Protons greater than 10 MeV at geosynchronous orbit reached a peak level of 4 pfu at 19/2255Z. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on days one and two (21 May, 22 May) and unsettled to active levels on day three (23 May). Protons have a chance of crossing threshold on days one, two, and three (21 May, 22 May, 23 May). III. Event probabilities 21 May-23 May Class M 65/65/65 Class X 25/25/25 Proton 25/25/25 PCAF green IV. Penticton 10.7 cm Flux Observed 20 May 132 Predicted 21 May-23 May 130/125/125 90 Day Mean 20 May 121 V. Geomagnetic A Indices Observed Afr/Ap 19 May 011/014 Estimated Afr/Ap 20 May 006/006 Predicted Afr/Ap 21 May-23 May 007/008-011/012-012/015 VI. Geomagnetic Activity Probabilities 21 May-23 May A. Middle Latitudes Active 15/20/30 Minor Storm 01/05/10 Major-severe storm 01/01/01 B. High Latitudes Active 15/15/15 Minor Storm 25/25/30 Major-severe storm 20/30/40