Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 17 April 2017

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 107 Issued at 2200Z on 17 Apr 2017

IA.  Analysis of Solar Active Regions and Activity from 16/2100Z to 17/2100Z: 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 17/0247Z. There are currently 0 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 and a slight chance for an M-class flare on days one, two, and three (18 Apr, 19 Apr, 20 Apr).

IIA.  Geophysical Activity Summary 16/2100Z to 17/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed reached a peak of 330 km/s at 17/1332Z. Total IMF reached 5 nT at 17/0439Z. The maximum southward component of Bz reached -4 nT at 17/0511Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 1717 pfu.

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

III.  Event probabilities 18 Apr-20 Apr
Class M    10/15/20
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           17 Apr 075
Predicted   18 Apr-20 Apr 020/018/015
90 Day Mean        17 Apr 078

V.  Geomagnetic A Indices
Observed Afr/Ap 16 Apr  004/004
Estimated Afr/Ap 17 Apr  008/011
Predicted Afr/Ap 18 Apr-20 Apr  016/020-013/018-012/015

VI.  Geomagnetic Activity Probabilities 18 Apr-20 Apr
A.  Middle Latitudes
Active                40/35/40
Minor Storm           20/15/15
Major-severe storm    01/01/01
B.  High Latitudes
Active                10/10/10
Minor Storm           20/25/25
Major-severe storm    55/50/50