Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 19 September 2015

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 262 Issued at 2200Z on 19 Sep 2015

IA. Analysis of Solar Active Regions and Activity from 18/2100Z to 19/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C1 event observed at 19/1712Z from Region 2415 (S19W41). There are currently 3 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is likely to be low with a slight chance for an M-class flare on days one, two, and three (20 Sep, 21 Sep, 22 Sep).

IIA. Geophysical Activity Summary 18/2100Z to 19/2100Z: The geomagnetic field has been at quiet to minor storm levels for the past 24 hours. Solar wind speed, as measured by the ACE spacecraft, reached a peak speed of 483 km/s at 19/0518Z. Total IMF reached 10 nT at 19/0251Z. The maximum southward component of Bz reached -8 nT at 19/0628Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 425 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at unsettled to minor storm levels on days one and two (20 Sep, 21 Sep) and unsettled to active levels on day three (22 Sep).

III. Event probabilities 20 Sep-22 Sep
Class M 20/20/20
Class X 05/05/05
Proton 05/05/05
PCAF green

IV. Penticton 10.7 cm Flux
Observed 19 Sep 106
Predicted 20 Sep-22 Sep 110/110/110
90 Day Mean 19 Sep 104

V. Geomagnetic A Indices
Observed Afr/Ap 18 Sep 011/014
Estimated Afr/Ap 19 Sep 013/016
Predicted Afr/Ap 20 Sep-22 Sep 020/030-022/030-015/018

VI. Geomagnetic Activity Probabilities 20 Sep-22 Sep
A. Middle Latitudes
Active 40/40/25
Minor Storm 20/20/10
Major-severe storm 01/01/01
B. High Latitudes
Active 10/10/15
Minor Storm 30/30/30
Major-severe storm 50/50/35