From: Space Weather Prediction Center (NOAA)
Posted: Saturday, July 17, 2021
Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 198 Issued at 2200Z on 17 Jul 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 4 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 Jul, 19 Jul, 20 Jul). IIA. Geophysical Activity Summary 16/2100Z to 17/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed reached a peak of 436 km/s at 17/1119Z. Total IMF reached 5 nT at 17/2037Z. The maximum southward component of Bz reached -3 nT at 17/1401Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 386 pfu.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet levels on days one, two, and three (18 Jul, 19 Jul, 20 Jul).
III. Event probabilities 18 Jul-20 Jul
Class M 01/01/01
Class X 01/01/01
IV. Penticton 10.7 cm Flux
Observed 17 Jul 077
Predicted 18 Jul-20 Jul 077/077/080
90 Day Mean 17 Jul 078
V. Geomagnetic A Indices
Observed Afr/Ap 16 Jul 005/004
Estimated Afr/Ap 17 Jul 005/005
Predicted Afr/Ap 18 Jul-20 Jul 006/005-006/005-006/005
VI. Geomagnetic Activity Probabilities 18 Jul-20 Jul
A. Middle Latitudes
Minor Storm 01/01/01
Major-severe storm 01/01/01
B. High Latitudes
Minor Storm 20/20/20
Major-severe storm 10/10/10
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