Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 24 July 2021

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 205 Issued at 2200Z on 24 Jul 2021

IA. Analysis of Solar Active Regions and Activity from 23/2100Z to 24/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C4 event observed at 24/0033Z from Region 2849 (S27E25). There are currently 4 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is expected to be very low with a slight chance for a C-class flare on days one, two, and three (25 Jul, 26 Jul, 27 Jul).

IIA. Geophysical Activity Summary 23/2100Z to 24/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed reached a peak of 406 km/s at 23/2254Z. Total IMF reached 6 nT at 24/0413Z. The maximum southward component of Bz reached -4 nT at 24/1328Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 309 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet levels on days one, two, and three (25 Jul, 26 Jul, 27 Jul).

III. Event probabilities 25 Jul-27 Jul
Class M 01/01/01
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 24 Jul 084
Predicted 25 Jul-27 Jul 085/085/085
90 Day Mean 24 Jul 078

V. Geomagnetic A Indices
Observed Afr/Ap 23 Jul 003/003
Estimated Afr/Ap 24 Jul 006/006
Predicted Afr/Ap 25 Jul-27 Jul 006/005-005/005-005/005

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