Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 17 August 2021

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 229 Issued at 2200Z on 17 Aug 2021

IA. Analysis of Solar Active Regions and Activity from 16/2100Z to 17/2100Z: Solar activity has been at very low levels for the past 24 hours. There are currently 1 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 (18 Aug, 19 Aug, 20 Aug).

IIA. Geophysical Activity Summary 16/2100Z to 17/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 492 km/s at 16/2317Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 618 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet levels on days one, two, and three (18 Aug, 19 Aug, 20 Aug).

III. Event probabilities 18 Aug-20 Aug
Class M 01/01/01
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 17 Aug 073
Predicted 18 Aug-20 Aug 073/073/073
90 Day Mean 17 Aug 079

V. Geomagnetic A Indices
Observed Afr/Ap 16 Aug 008/007
Estimated Afr/Ap 17 Aug 005/005
Predicted Afr/Ap 18 Aug-20 Aug 005/005-005/005-005/005

VI. Geomagnetic Activity Probabilities 18 Aug-20 Aug
A. Middle Latitudes
Active 10/10/10
Minor Storm 01/01/01
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 20/20/20
Major-severe storm 15/15/15