Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 28 April 2017

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 118 Issued at 2200Z on 28 Apr 2017

IA.  Analysis of Solar Active Regions and Activity from 27/2100Z to 28/2100Z: Solar activity has been at very low levels for the past 24 hours. There are currently 3 numbered sunspot regions on the disk.

IB.  Solar Activity Forecast: Solar activity is expected to be very low with a slight chance for a C-class flare on days one, two, and three (29 Apr, 30 Apr, 01 May).

IIA.  Geophysical Activity Summary 27/2100Z to 28/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed reached a peak of 493 km/s at 27/2351Z. Total IMF reached 5 nT at 28/1949Z. The maximum southward component of Bz reached -5 nT at 28/2049Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 56297 pfu.  NOTE:  From 28/1727-1913 UTC, solar wind speed, temperature, and density registered incorrect readings.

IIB.  Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet levels on day one (29 Apr), quiet to unsettled levels on day two (30 Apr) and quiet to active levels on day three (01 May).

III.  Event probabilities 29 Apr-01 May
Class M    01/01/01
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           28 Apr 078
Predicted   29 Apr-01 May 078/078/076
90 Day Mean        28 Apr 077

V.  Geomagnetic A Indices
Observed Afr/Ap 27 Apr  010/008
Estimated Afr/Ap 28 Apr  005/006
Predicted Afr/Ap 29 Apr-01 May  005/005-008/008-011/012

VI.  Geomagnetic Activity Probabilities 29 Apr-01 May
A.  Middle Latitudes
Active                05/10/25
Minor Storm           01/05/05
Major-severe storm    01/01/01
B.  High Latitudes
Active                15/15/15
Minor Storm           15/20/30
Major-severe storm    10/20/30