Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 16 April 2021

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 106 Issued at 2200Z on 16 Apr 2021

IA. Analysis of Solar Active Regions and Activity from 15/2100Z to 16/2100Z: 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 chance for a C-class flares on days one, two, and three (17 Apr, 18 Apr, 19 Apr).

IIA. Geophysical Activity Summary 15/2100Z to 16/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 490 km/s at 16/1213Z. Total IMF reached 13 nT at 16/1558Z. The maximum southward component of Bz reached -10 nT at 16/1806Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 134 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to minor storm levels on day one (17 Apr) and quiet to active levels on days two and three (18 Apr, 19 Apr).

III. Event probabilities 17 Apr-19 Apr
Class M 01/01/01
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 16 Apr 077
Predicted 17 Apr-19 Apr 078/078/078
90 Day Mean 16 Apr 076

V. Geomagnetic A Indices
Observed Afr/Ap 15 Apr 011/010
Estimated Afr/Ap 16 Apr 016/020
Predicted Afr/Ap 17 Apr-19 Apr 015/020-015/018-011/012

VI. Geomagnetic Activity Probabilities 17 Apr-19 Apr
A. Middle Latitudes
Active 35/35/35
Minor Storm 25/15/15
Major-severe storm 05/01/01
B. High Latitudes
Active 10/10/10
Minor Storm 25/25/25
Major-severe storm 65/50/50