Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 19 April 2017

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 109 Issued at 2200Z on 19 Apr 2017

IA.  Analysis of Solar Active Regions and Activity from 18/2100Z to 19/2100Z: Solar activity has been at very low levels for the past 24 hours. There are currently 1 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 (20 Apr, 21 Apr, 22 Apr).

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 reached a peak of 487 km/s at 19/1906Z. Total IMF reached 15 nT at 19/2100Z. The maximum southward component of Bz reached -11 nT at 19/0105Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 501 pfu.

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

III.  Event probabilities 20 Apr-22 Apr
Class M    10/10/10
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           19 Apr 081
Predicted   20 Apr-22 Apr 085/085/085
90 Day Mean        19 Apr 078

V.  Geomagnetic A Indices
Observed Afr/Ap 18 Apr  006/006
Estimated Afr/Ap 19 Apr  012/016
Predicted Afr/Ap 20 Apr-22 Apr  012/015-007/008-007/008

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