Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 17 April 2022

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 107 Issued at 2200Z on 17 Apr 2022

IA. Analysis of Solar Active Regions and Activity from 16/2100Z to 17/2100Z: Solar activity has been at high levels for the past 24 hours. The largest solar event of the period was a X1 event observed at 17/0334Z from Region 2994 (N13E66). There are currently 5 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is expected to be moderate with a chance for X-class flares on days one, two, and three (18 Apr, 19 Apr, 20 Apr).

IIA. Geophysical Activity Summary 16/2100Z to 17/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 593 km/s at 16/2256Z. Total IMF reached 10 nT at 17/2038Z. The maximum southward component of Bz reached -7 nT at 17/1354Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 2314 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on day one (18 Apr) and quiet to unsettled levels on days two and three (19 Apr, 20 Apr).

III. Event probabilities 18 Apr-20 Apr
Class M 75/75/75
Class X 25/25/25
Proton 05/05/05
PCAF green

IV. Penticton 10.7 cm Flux
Observed 17 Apr 135
Predicted 18 Apr-20 Apr 135/130/130
90 Day Mean 17 Apr 113

V. Geomagnetic A Indices
Observed Afr/Ap 16 Apr 007/006
Estimated Afr/Ap 17 Apr 010/012
Predicted Afr/Ap 18 Apr-20 Apr 011/012-009/010-009/010

VI. Geomagnetic Activity Probabilities 18 Apr-20 Apr
A. Middle Latitudes
Active 30/25/25
Minor Storm 10/05/05
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 25/30/30
Major-severe storm 40/30/30