Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 31 July 2021

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 212 Issued at 2200Z on 31 Jul 2021

IA. Analysis of Solar Active Regions and Activity from 30/2100Z to 31/2100Z: Solar activity has been at very low levels for the past 24 hours. There are currently 0 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is expected to be very low on days one, two, and three (01 Aug, 02 Aug, 03 Aug).

IIA. Geophysical Activity Summary 30/2100Z to 31/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed reached a peak of 492 km/s at 30/2102Z. Total IMF reached 6 nT at 30/2338Z. The maximum southward component of Bz reached -2 nT at 31/1817Z. Electrons greater than 2 MeV at geosynchronous orbit reacheda peak level of 379 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on day one (01 Aug), quiet to unsettled

III. Event probabilities 01 Aug-03 Aug
Class M 01/01/01
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 31 Jul 076
Predicted 01 Aug-03 Aug 074/072/072
90 Day Mean 31 Jul 079

V. Geomagnetic A Indices
Observed Afr/Ap 30 Jul 006/008
Estimated Afr/Ap 31 Jul 008/009
Predicted Afr/Ap 01 Aug-03 Aug 010/012-007/008-006/005

VI. Geomagnetic Activity Probabilities 01 Aug-03 Aug
A. Middle Latitudes
Active 30/20/15
Minor Storm 10/05/01
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 30/25/20
Major-severe storm 40/25/20