From: Space Weather Prediction Center (NOAA)
Posted: Tuesday, July 20, 2021
Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 201 Issued at 2200Z on 20 Jul 2021 IA. Analysis of Solar Active Regions and Activity from 19/2100Z to 20/2100Z: 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 chance for a C-class flares on days one, two, and three (21 Jul, 22 Jul, 23 Jul). IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 539 km/s at 20/1819Z. Total IMF reached 7 nT at 20/0240Z. The maximum southward component of Bz reached -6 nT at 19/2334Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 267 pfu.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on days one and two (21 Jul, 22 Jul) and quiet levels on day three (23 Jul).
III. Event probabilities 21 Jul-23 Jul
Class M 05/05/05
Class X 01/01/01
IV. Penticton 10.7 cm Flux
Observed 20 Jul 087
Predicted 21 Jul-23 Jul 088/090/088
90 Day Mean 20 Jul 078
V. Geomagnetic A Indices
Observed Afr/Ap 19 Jul 004/009
Estimated Afr/Ap 20 Jul 008/008
Predicted Afr/Ap 21 Jul-23 Jul 006/008-009/008-006/005
VI. Geomagnetic Activity Probabilities 21 Jul-23 Jul
A. Middle Latitudes
Minor Storm 05/05/01
Major-severe storm 01/01/01
B. High Latitudes
Minor Storm 25/25/20
Major-severe storm 25/25/10
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