Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 26 August 2021

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 238 Issued at 2200Z on 26 Aug 2021

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 26/1818Z. There are currently 3 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is expected to be very low with a chance for a C-class flares on days one, two, and three (27 Aug, 28 Aug, 29 Aug).

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 417 km/s at 26/0247Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 139 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on days one and two (27 Aug, 28 Aug) and quiet to unsettled levels on day three (29 Aug).

III. Event probabilities 27 Aug-29 Aug
Class M 05/05/05
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 26 Aug 089
Predicted 27 Aug-29 Aug 090/090/090
90 Day Mean 26 Aug 079

V. Geomagnetic A Indices
Observed Afr/Ap 25 Aug 008/010
Estimated Afr/Ap 26 Aug 011/014
Predicted Afr/Ap 27 Aug-29 Aug 012/016-009/012-007/010

VI. Geomagnetic Activity Probabilities 27 Aug-29 Aug
A. Middle Latitudes
Active 40/30/20
Minor Storm 20/10/05
Major-severe storm 05/01/01
B. High Latitudes
Active 10/15/15
Minor Storm 25/30/30
Major-severe storm 55/40/25