Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 27 April 2022

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 116 Issued at 2200Z on 26 Apr 2022

IA. Analysis of Solar Active Regions and Activity from 25/2100Z to 26/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C3 event observed at 26/1624Z. There are currently 8 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is expected to be low with a chance for M-class flares and a slight chance for an X-class flare on days one, two, and three (27 Apr, 28 Apr, 29 Apr).

IIA. Geophysical Activity Summary 25/2100Z to 26/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed reached a peak of 559 km/s at 26/0144Z. Total IMF reached 5 nT at 26/0904Z. The maximum southward component of Bz reached -4 nT at 26/1123Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 591 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet levels on days one and two (27 Apr, 28 Apr) and unsettled to minor storm levels on day three (29 Apr). Protons have a slight chance of crossing threshold on days one, two, and three (27 Apr, 28 Apr, 29 Apr).

III. Event probabilities 27 Apr-29 Apr
Class M 30/30/30
Class X 10/10/10
Proton 10/10/10
PCAF green

IV. Penticton 10.7 cm Flux
Observed 26 Apr 150
Predicted 27 Apr-29 Apr 148/145/130
90 Day Mean 26 Apr 119

V. Geomagnetic A Indices
Observed Afr/Ap 25 Apr 004/004
Estimated Afr/Ap 26 Apr 004/004
Predicted Afr/Ap 27 Apr-29 Apr 005/005-005/005-013/018

VI. Geomagnetic Activity Probabilities 27 Apr-29 Apr
A. Middle Latitudes
Active 15/15/40
Minor Storm 01/01/25
Major-severe storm 01/01/05
B. High Latitudes
Active 15/15/10
Minor Storm 20/20/25
Major-severe storm 20/20/60