Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 18 April 2022

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 108 Issued at 2200Z on 18 Apr 2022

IA. Analysis of Solar Active Regions and Activity from 17/2100Z to 18/2100Z: Solar activity has been at moderate levels for the past 24 hours. The largest solar event of the period was a M4 event observed at 17/2234Z from Region 2992 (S31W76). 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 (19 Apr, 20 Apr, 21 Apr).

IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 600 km/s at 18/0234Z. Total IMF reached 10 nT at 17/2147Z. The maximum southward component of Bz reached -6 nT at 18/0926Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 1646 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on days one, two, and three (19 Apr, 20 Apr, 21 Apr).

III. Event probabilities 19 Apr-21 Apr
Class M 75/75/75
Class X 25/25/25
Proton 05/05/05
PCAF green

IV. Penticton 10.7 cm Flux
Observed 18 Apr 135
Predicted 19 Apr-21 Apr 130/130/130
90 Day Mean 18 Apr 113

V. Geomagnetic A Indices
Observed Afr/Ap 17 Apr 009/011
Estimated Afr/Ap 18 Apr 009/011
Predicted Afr/Ap 19 Apr-21 Apr 009/010-009/010-008/008

VI. Geomagnetic Activity Probabilities 19 Apr-21 Apr
A. Middle Latitudes
Active 25/25/20
Minor Storm 05/05/05
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 30/30/25
Major-severe storm 30/30/30