Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 15 May 2021

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 135 Issued at 2200Z on 15 May 2021

IA. Analysis of Solar Active Regions and Activity from 14/2100Z to 15/2100Z: 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 (16 May, 17 May, 18 May).

IIA. Geophysical Activity Summary 14/2100Z to 15/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 479 km/s at 15/0949Z. Total IMF reached 9 nT at 15/0446Z. The maximum southward component of Bz reached -6 nT at 15/0543Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 192 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet levels on day one (16 May), quiet to active levels on day two (17 May) and quiet to minor storm levels on day three (18 May).

III. Event probabilities 16 May-18 May
Class M 01/01/01
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 15 May 073
Predicted 16 May-18 May 073/073/077
90 Day Mean 15 May 076

V. Geomagnetic A Indices
Observed Afr/Ap 14 May 004/005
Estimated Afr/Ap 15 May 005/005
Predicted Afr/Ap 16 May-18 May 006/005-008/012-015/018

VI. Geomagnetic Activity Probabilities 16 May-18 May
A. Middle Latitudes
Active 15/35/35
Minor Storm 05/10/20
Major-severe storm 01/01/05
B. High Latitudes
Active 15/15/10
Minor Storm 20/30/25
Major-severe storm 20/45/50