Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 18 September 2015

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 261 Issued at 2200Z on 18 Sep 2015

IA. Analysis of Solar Active Regions and Activity from 17/2100Z to 18/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C6 event observed at 17/2115Z 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 (19 Sep, 20 Sep, 21 Sep).

IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed, as measured by the ACE spacecraft, reached a peak speed of 465 km/s at 18/1544Z. Total IMF reached 7 nT at 18/1209Z. The maximum southward component of Bz reached -6 nT at 18/1149Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 3502 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on day one (19 Sep), unsettled to minor storm levels on day two (20 Sep) and active to minor storm levels on day three (21 Sep).

III. Event probabilities 19 Sep-21 Sep
Class M 25/25/25
Class X 05/05/05
Proton 05/05/05
PCAF green

IV. Penticton 10.7 cm Flux
Observed 18 Sep 103
Predicted 19 Sep-21 Sep 105/110/110
90 Day Mean 18 Sep 104

V. Geomagnetic A Indices
Observed Afr/Ap 17 Sep 012/011
Estimated Afr/Ap 18 Sep 010/011
Predicted Afr/Ap 19 Sep-21 Sep 014/016-018/025-021/030

VI. Geomagnetic Activity Probabilities 19 Sep-21 Sep
A. Middle Latitudes
Active 30/40/40
Minor Storm 10/20/20
Major-severe storm 01/01/01
B. High Latitudes
Active 15/10/10
Minor Storm 30/30/30
Major-severe storm 35/50/50