Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 21 April 2018

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 111 Issued at 2200Z on 21 Apr 2018

IA.  Analysis of Solar Active Regions and Activity from 20/2100Z to 21/2100Z: Solar activity has been at very low levels for the past 24 hours. There are currently 2 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 on days one, two, and three (22 Apr, 23 Apr, 24 Apr).

IIA.  Geophysical Activity Summary 20/2100Z to 21/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 630 km/s at 20/2357Z. Total IMF reached 6 nT at 21/0701Z. The maximum southward component of Bz reached -5 nT at 20/2308Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 21310 pfu.

IIB.  Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on day one (22 Apr) and quiet levels on days two and three (23 Apr, 24 Apr).

III.  Event probabilities 22 Apr-24 Apr
Class M    01/01/01
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           21 Apr 077
Predicted   22 Apr-24 Apr 078/078/078
90 Day Mean        21 Apr 070

V.  Geomagnetic A Indices
Observed Afr/Ap 20 Apr  029/038
Estimated Afr/Ap 21 Apr  011/012
Predicted Afr/Ap 22 Apr-24 Apr  010/010-005/005-006/005

VI.  Geomagnetic Activity Probabilities 22 Apr-24 Apr
A.  Middle Latitudes
Active                30/10/10
Minor Storm           10/01/01
Major-severe storm    01/01/01
B.  High Latitudes
Active                20/20/20
Minor Storm           30/20/20
Major-severe storm    35/10/10