Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 17 September 2015

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 260 Issued at 2200Z on 17 Sep 2015

IA. Analysis of Solar Active Regions and Activity from 16/2100Z to 17/2100Z: 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 17/0940Z from Region 2415 (S20W16). There are currently 3 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is expected to be low with a chance for M-class flares on days one, two, and three (18 Sep, 19 Sep, 20 Sep).

IIA. Geophysical Activity Summary 16/2100Z to 17/2100Z: 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 535 km/s at 17/0729Z. Total IMF reached 6 nT at 17/1820Z. The maximum southward component of Bz reached -5 nT at 16/2300Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 6939 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on day one (18 Sep) and quiet to active levels on days two and three (19 Sep, 20 Sep).

III. Event probabilities 18 Sep-20 Sep
Class M 25/25/25
Class X 05/05/05
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 17 Sep 107
Predicted 18 Sep-20 Sep 110/110/110
90 Day Mean 17 Sep 104

V. Geomagnetic A Indices
Observed Afr/Ap 16 Sep 009/009
Estimated Afr/Ap 17 Sep 012/012
Predicted Afr/Ap 18 Sep-20 Sep 009/008-009/012-014/016

VI. Geomagnetic Activity Probabilities 18 Sep-20 Sep
A. Middle Latitudes
Active 20/25/30
Minor Storm 05/10/15
Major-severe storm 01/01/01
B. High Latitudes
Active 20/15/15
Minor Storm 25/30/30
Major-severe storm 25/35/45