Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 20 April 2020

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 111 Issued at 2200Z on 20 Apr 2020

IA. Analysis of Solar Active Regions and Activity from 19/2100Z to 20/2100Z: Solar activity has been at very low levels for the past 24 hours. There are currently 0 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is expected to be very low on days one, two, and three (21 Apr, 22 Apr, 23 Apr).

IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z: The geomagnetic field has been at quiet to minor storm levels for the past 24 hours. Solar wind speed reached a peak of 388 km/s at 20/0826Z. Total IMF reached 16 nT at 20/1355Z. The maximum southward component of Bz reached -15 nT at 20/0810Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 185 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at unsettled to active levels on day one (21 Apr) and quiet to unsettled levels on days two and three (22 Apr, 23 Apr).

III. Event probabilities 21 Apr-23 Apr
Class M 01/01/01
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 20 Apr 068
Predicted 21 Apr-23 Apr 069/069/069
90 Day Mean 20 Apr 071

V. Geomagnetic A Indices
Observed Afr/Ap 19 Apr 002/005
Estimated Afr/Ap 20 Apr 015/020
Predicted Afr/Ap 21 Apr-23 Apr 011/014-007/008-007/010

VI. Geomagnetic Activity Probabilities 21 Apr-23 Apr
A. Middle Latitudes
Active 30/15/20
Minor Storm 10/05/05
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 30/25/25
Major-severe storm 40/25/30