Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 28 July 2021

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 209 Issued at 2200Z on 28 Jul 2021

IA. Analysis of Solar Active Regions and Activity from 27/2100Z to 28/2100Z: 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 (29 Jul, 30 Jul, 31 Jul).

IIA. Geophysical Activity Summary 27/2100Z to 28/2100Z: The geomagnetic field has been at quiet to active levels for the past 24 hours. Solar wind speed reached a peak of 544 km/s at 28/2028Z. Total IMF reached 17 nT at 28/1038Z. The maximum southward component of Bz reached -11 nT at 28/0151Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 263 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on day one (29 Jul) and quiet to unsettled levels on days two and three (30 Jul, 31 Jul).

III. Event probabilities 29 Jul-31 Jul
Class M 01/01/01
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 28 Jul 079
Predicted 29 Jul-31 Jul 080/078/078
90 Day Mean 28 Jul 079

V. Geomagnetic A Indices
Observed Afr/Ap 27 Jul 006/005
Estimated Afr/Ap 28 Jul 011/013
Predicted Afr/Ap 29 Jul-31 Jul 010/012-008/008-008/010

VI. Geomagnetic Activity Probabilities 29 Jul-31 Jul
A. Middle Latitudes
Active 35/15/25
Minor Storm 15/05/05
Major-severe storm 01/01/01
B. High Latitudes
Active 10/20/15
Minor Storm 30/25/30
Major-severe storm 50/20/30