Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 137 Issued at 2200Z on 17 May 2023
IA. Analysis of Solar Active Regions and Activity from 16/2100Z to 17/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C7 event observed at 17/1628Z. There are currently 7 numbered sunspot regions on the disk.
IB. Solar Activity Forecast: Solar activity is expected to be low with a chance for M-class flares on days one, two, and three (18 May, 19 May, 20 May).
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 488 km/s at 16/2101Z. Total IMF reached 6 nT at 16/2105Z. The maximum southward component of Bz reached -3 nT at 17/0016Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 162 pfu.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet levels on days one and two (18 May, 19 May) and quiet to unsettled levels on day three (20 May).
III. Event probabilities 18 May-20 May
Class M 25/25/25
Class X 05/05/05
Proton 01/01/01
PCAF green
IV. Penticton 10.7 cm Flux
Observed 17 May 138
Predicted 18 May-20 May 140/138/135
90 Day Mean 17 May 155
V. Geomagnetic A Indices
Observed Afr/Ap 16 May 010/009
Estimated Afr/Ap 17 May 004/005
Predicted Afr/Ap 18 May-20 May 006/005-006/005-008/008
VI. Geomagnetic Activity Probabilities 18 May-20 May
A. Middle Latitudes
Active 10/10/20
Minor Storm 05/01/05
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 20/20/20
Major-severe storm 15/10/25
space weather
