Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 28 September 2017

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 271 Issued at 2200Z on 28 Sep 2017

IA.  Analysis of Solar Active Regions and Activity from 27/2100Z to 28/2100Z: Solar activity has been at very low levels for the past 24 hours. There are currently 3 numbered sunspot regions on the disk.

IB.  Solar Activity Forecast: Solar activity is expected to be very low with a chance for a C-class flares on days one, two, and three (29 Sep, 30 Sep, 01 Oct).

IIA.  Geophysical Activity Summary 27/2100Z to 28/2100Z: The geomagnetic field has been at active to severe storm levels for the past 24 hours. Solar wind speed reached a peak of 752 km/s at 28/0846Z. Total IMF reached 13 nT at 28/0108Z. The maximum southward component of Bz reached -11 nT at 27/2128Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 3706 pfu.

IIB.  Geophysical Activity Forecast: The geomagnetic field is expected to be at unsettled to minor storm levels on day one (29 Sep) and quiet to active levels on days two and three (30 Sep, 01 Oct).

III.  Event probabilities 29 Sep-01 Oct
Class M    01/01/01
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           28 Sep 091
Predicted   29 Sep-01 Oct 091/091/091
90 Day Mean        28 Sep 082

V.  Geomagnetic A Indices
Observed Afr/Ap 27 Sep  024/037
Estimated Afr/Ap 28 Sep  043/061
Predicted Afr/Ap 29 Sep-01 Oct  021/028-014/018-011/014

VI.  Geomagnetic Activity Probabilities 29 Sep-01 Oct
A.  Middle Latitudes
Active                35/30/30
Minor Storm           30/15/15
Major-severe storm    05/01/01
B.  High Latitudes
Active                10/10/15
Minor Storm           20/30/25
Major-severe storm    60/50/50