Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 19 April 2021

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 109 Issued at 2200Z on 19 Apr 2021

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 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 (20 Apr, 21 Apr, 22 Apr).

IIA. Geophysical Activity Summary 18/2100Z to 19/2100Z: The geomagnetic field has been at unsettled to active levels for the past 24 hours. Solar wind speed reached a peak of 689 km/s at 19/1639Z. Total IMF reached 6 nT at 19/0013Z. The maximum southward component of Bz reached -6 nT at 19/0255Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 10148 pfu.

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

III. Event probabilities 20 Apr-22 Apr
Class M 05/05/05
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 19 Apr 086
Predicted 20 Apr-22 Apr 085/085/085
90 Day Mean 19 Apr 076

V. Geomagnetic A Indices
Observed Afr/Ap 18 Apr 013/016
Estimated Afr/Ap 19 Apr 011/014
Predicted Afr/Ap 20 Apr-22 Apr 009/008-006/005-005/005

VI. Geomagnetic Activity Probabilities 20 Apr-22 Apr
A. Middle Latitudes
Active 30/15/15
Minor Storm 10/01/01
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 30/20/20
Major-severe storm 40/20/20