Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 31 August 2015

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 243 Issued at 2200Z on 31 Aug 2015

IA. Analysis of Solar Active Regions and Activity from 30/2100Z to 31/2100Z: 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 31/0522Z from Region 2403 (S15W99). There are currently 4 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is expected to be very low with a slight chance for a C-class flare on days one, two, and three (01 Sep, 02 Sep, 03 Sep).

IIA. Geophysical Activity Summary 30/2100Z to 31/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed, as measured by the ACE spacecraft, reached a peak speed of 444 km/s at 30/2112Z. Total IMF reached 7 nT at 30/2323Z. The maximum southward component of Bz reached -4 nT at 30/2208Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 2912 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to minor storm levels on day one (01 Sep), unsettled to minor storm levels on day two (02 Sep) and quiet to active levels on day three (03 Sep).

III. Event probabilities 01 Sep-03 Sep
Class M 05/01/01
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 31 Aug 091
Predicted 01 Sep-03 Sep 085/080/080
90 Day Mean 31 Aug 112

V. Geomagnetic A Indices
Observed Afr/Ap 30 Aug 005/004
Estimated Afr/Ap 31 Aug 006/008
Predicted Afr/Ap 01 Sep-03 Sep 014/020-017/022-011/014

VI. Geomagnetic Activity Probabilities 01 Sep-03 Sep
A. Middle Latitudes
Active 45/45/30
Minor Storm 25/25/15
Major-severe storm 05/05/05
B. High Latitudes
Active 10/10/10
Minor Storm 25/25/25
Major-severe storm 65/70/50