Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 19 May 2013
Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 139 Issued at 2200Z on 19 May 2013 IA. Analysis of Solar Active Regions and Activity from 18/2100Z to 19/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C9 event observed at 19/1750Z. 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 (20 May, 21 May, 22 May). IIA. Geophysical Activity Summary 18/2100Z to 19/2100Z: 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 446 km/s at 19/0021Z. Total IMF reached 8 nT at 18/2101Z. The maximum southward component of Bz reached -6 nT at 18/2258Z. Protons greater than 10 MeV at geosynchronous orbit reached a peak level of 7 pfu at 18/2130Z. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to major storm levels on day one (20 May), quiet to unsettled levels on day two (21 May) and quiet to active levels on day three (22 May). Protons have a chance of crossing threshold on days one, two, and three (20 May, 21 May, 22 May). III. Event probabilities 20 May-22 May Class M 65/65/65 Class X 25/25/25 Proton 25/25/25 PCAF yellow IV. Penticton 10.7 cm Flux Observed 19 May 135 Predicted 20 May-22 May 135/130/125 90 Day Mean 19 May 121 V. Geomagnetic A Indices Observed Afr/Ap 18 May 016/024 Estimated Afr/Ap 19 May 014/020 Predicted Afr/Ap 20 May-22 May 019/030-007/008-012/015 VI. Geomagnetic Activity Probabilities 20 May-22 May A. Middle Latitudes Active 35/15/30 Minor Storm 30/05/10 Major-severe storm 20/01/01 B. High Latitudes Active 05/15/15 Minor Storm 20/25/30 Major-severe storm 75/25/40
