Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 21 July 2021

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 202 Issued at 2200Z on 21 Jul 2021

IA. Analysis of Solar Active Regions and Activity from 20/2100Z to 21/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C1 event observed at 21/2005Z from Region 2845 (S15W61). There are currently 6 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is likely to be low on days one and two (22 Jul, 23 Jul) and expected to be very low with a chance for a C-class flares on day three (24 Jul).

IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 543 km/s at 21/0811Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 274 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on day one (22 Jul), quiet to minor storm levels on day two (23 Jul) and quiet to active levels on day three (24 Jul).

III. Event probabilities 22 Jul-24 Jul
Class M 05/05/01
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 21 Jul 094
Predicted 22 Jul-24 Jul 094/092/090
90 Day Mean 21 Jul 078

V. Geomagnetic A Indices
Observed Afr/Ap 20 Jul 009/010
Estimated Afr/Ap 21 Jul 007/007
Predicted Afr/Ap 22 Jul-24 Jul 007/008-013/018-013/016

VI. Geomagnetic Activity Probabilities 22 Jul-24 Jul
A. Middle Latitudes
Active 20/40/35
Minor Storm 05/25/20
Major-severe storm 01/05/05
B. High Latitudes
Active 15/10/10
Minor Storm 25/25/25
Major-severe storm 25/60/50