Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 19 May 2021

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 139 Issued at 2200Z on 19 May 2021

IA. Analysis of Solar Active Regions and Activity from 18/2100Z to 19/2100Z: 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 days one, two, and three (20 May, 21 May, 22 May).

IIA. Geophysical Activity Summary 18/2100Z to 19/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed reached a peak of 386 km/s at 19/0701Z. Total IMF reached 9 nT at 19/0712Z. The maximum southward component of Bz reached -3 nT at 19/1925Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 154 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on days one, two, and three (20 May, 21 May, 22 May).

III. Event probabilities 20 May-22 May
Class M 01/01/01
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 19 May 076
Predicted 20 May-22 May 074/073/073
90 Day Mean 19 May 076

V. Geomagnetic A Indices
Observed Afr/Ap 18 May 010/010
Estimated Afr/Ap 19 May 008/010
Predicted Afr/Ap 20 May-22 May 007/008-008/008-008/008

VI. Geomagnetic Activity Probabilities 20 May-22 May
A. Middle Latitudes
Active 15/15/15
Minor Storm 01/01/01
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 25/25/25
Major-severe storm 20/20/20