Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 15 April 2021

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 105 Issued at 2200Z on 15 Apr 2021

IA. Analysis of Solar Active Regions and Activity from 14/2100Z to 15/2100Z: 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 slight chance for a C-class flare on days one, two, and three (16 Apr, 17 Apr, 18 Apr).

IIA. Geophysical Activity Summary 14/2100Z to 15/2100Z: The geomagnetic field has been at quiet to minor storm levels for the past 24 hours. Solar wind speed reached a peak of 413 km/s at 15/0533Z. Total IMF reached 10 nT at 15/1242Z. The maximum southward component of Bz reached -7 nT at 15/0533Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 164 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on days one and three (16 Apr, 18 Apr) and quiet to minor storm levels on day two (17 Apr).

III. Event probabilities 16 Apr-18 Apr
Class M 01/01/01
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 15 Apr 072
Predicted 16 Apr-18 Apr 074/074/074
90 Day Mean 15 Apr 076

V. Geomagnetic A Indices
Observed Afr/Ap 14 Apr 007/006
Estimated Afr/Ap 15 Apr 012/015
Predicted Afr/Ap 16 Apr-18 Apr 014/018-015/020-015/016

VI. Geomagnetic Activity Probabilities 16 Apr-18 Apr
A. Middle Latitudes
Active 40/40/35
Minor Storm 15/25/15
Major-severe storm 01/05/01
B. High Latitudes
Active 10/10/10
Minor Storm 25/25/25
Major-severe storm 50/65/50