Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 27 July 2021

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 208 Issued at 2200Z on 27 Jul 2021

IA. Analysis of Solar Active Regions and Activity from 26/2100Z to 27/2100Z: Solar activity has been at very low levels for the past 24 hours. There are currently 2 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 day one (28 Jul) and expected to be very low on days two and three (29 Jul, 30 Jul).

IIA. Geophysical Activity Summary 26/2100Z to 27/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed reached a peak of 336 km/s at 27/2053Z. Total IMF reached 10 nT at 27/2047Z. The maximum southward component of Bz reached -2 nT at 27/1255Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 410 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on day one (28 Jul), quiet to unsettled levels on day two (29 Jul) and quiet levels on day three (30 Jul).

III. Event probabilities 28 Jul-30 Jul
Class M 01/01/01
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 27 Jul 080
Predicted 28 Jul-30 Jul 080/078/078
90 Day Mean 27 Jul 079

V. Geomagnetic A Indices
Observed Afr/Ap 26 Jul 004/004
Estimated Afr/Ap 27 Jul 005/006
Predicted Afr/Ap 28 Jul-30 Jul 010/012-008/010-005/005

VI. Geomagnetic Activity Probabilities 28 Jul-30 Jul
A. Middle Latitudes
Active 30/25/10
Minor Storm 10/05/01
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 30/30/20
Major-severe storm 40/30/20