Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 27 August 2015
Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 239 Issued at 2200Z on 27 Aug 2015
IA. Analysis of Solar Active Regions and Activity from 26/2100Z to 27/2100Z: Solar activity has been at moderate levels for the past 24 hours. The largest solar event of the period was a M2 event observed at 27/0544Z from Region 2403 (S15W57). There are currently 2 numbered sunspot regions on the disk.
IB. Solar Activity Forecast: Solar activity is likely to be moderate with a slight chance for an X-class flare on days one and two (28 Aug, 29 Aug) and expected to be low with a chance for M-class flares on day three (30 Aug).
IIA. Geophysical Activity Summary 26/2100Z to 27/2100Z: The geomagnetic field has been at active to major storm levels for the past 24 hours. Solar wind speed, as measured by the ACE spacecraft, reached a peak speed of 414 km/s at 27/0741Z. Total IMF reached 14 nT at 27/0313Z. The maximum southward component of Bz reached -13 nT at 27/0319Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 915 pfu.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at unsettled to minor storm levels on day one (28 Aug), quiet to active levels on day two (29 Aug) and quiet to unsettled levels on day three (30 Aug). Protons greater than 10 MeV have a slight chance of crossing threshold on days one and two (28 Aug, 29 Aug).
III. Event probabilities 28 Aug-30 Aug
Class M 60/55/50
Class X 10/10/05
Proton 10/10/05
PCAF green
IV. Penticton 10.7 cm Flux
Observed 27 Aug 110
Predicted 28 Aug-30 Aug 110/110/105
90 Day Mean 27 Aug 112
V. Geomagnetic A Indices
Observed Afr/Ap 26 Aug 019/028
Estimated Afr/Ap 27 Aug 029/045
Predicted Afr/Ap 28 Aug-30 Aug 017/018-011/012-007/008
VI. Geomagnetic Activity Probabilities 28 Aug-30 Aug
A. Middle Latitudes
Active 40/30/20
Minor Storm 25/10/05
Major-severe storm 05/01/01
B. High Latitudes
Active 10/15/15
Minor Storm 25/30/25
Major-severe storm 60/40/25
