Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 4 April 2017

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 94 Issued at 2200Z on 04 Apr 2017

IA.  Analysis of Solar Active Regions and Activity from 03/2100Z to 04/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C3 event observed at 04/0712Z from Region 2644 (N13W92). There are currently 4 numbered sunspot regions on the disk.

IB.  Solar Activity Forecast: Solar activity is likely to be low with a chance for M-class flares and a slight chance for an X-class flare on day one (05 Apr) and expected to be very low with a chance for a C-class flares and a slight chance for an M-class flare on days two and three (06 Apr, 07 Apr).

IIA.  Geophysical Activity Summary 03/2100Z to 04/2100Z: The geomagnetic field has been at quiet to minor storm levels for the past 24 hours. Solar wind speed reached a peak of 488 km/s at 04/1548Z. Total IMF reached 16 nT at 04/1035Z. The maximum southward component of Bz reached -13 nT at 04/0932Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 18021 pfu.

IIB.  Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on days one and three (05 Apr, 07 Apr) and quiet to unsettled levels on day two (06 Apr). Protons have a slight chance of crossing threshold on day one (05 Apr), have a slight chance of crossing threshold on day two (06 Apr) and have a slight chance of crossing threshold on day three (07 Apr).

III.  Event probabilities 05 Apr-07 Apr
Class M    35/20/10
Class X    15/05/05
Proton     20/15/10
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           04 Apr 094
Predicted   05 Apr-07 Apr 090/086/082
90 Day Mean        04 Apr 078

V.  Geomagnetic A Indices
Observed Afr/Ap 03 Apr  004/005
Estimated Afr/Ap 04 Apr  015/020
Predicted Afr/Ap 05 Apr-07 Apr  009/012-007/008-010/012

VI.  Geomagnetic Activity Probabilities 05 Apr-07 Apr
A.  Middle Latitudes
Active                20/15/25
Minor Storm           05/05/05
Major-severe storm    01/01/01
B.  High Latitudes
Active                15/15/15
Minor Storm           20/20/20
Major-severe storm    20/20/15