Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 113 Issued at 2200Z on 23 Apr 2023
IA. Analysis of Solar Active Regions and Activity from 22/2100Z to 23/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C2 event observed at 23/0640Z from Region 3279 (S19W78). There are currently 6 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 day one (24 Apr) and likely to be low with a chance for M-class flares on day two (25 Apr) and likely to be low on day three (26 Apr).
IIA. Geophysical Activity Summary 22/2100Z to 23/2100Z: The geomagnetic field has been at quiet to severe storm levels for the past 24 hours. Solar wind speed reached a peak of 733 km/s at 23/2057Z. Total IMF reached 29 nT at 23/2054Z. The maximum southward component of Bz reached -24 nT at 23/1710Z. Protons greater than 10 MeV at geosynchronous orbit reached a peak level of 26 pfu at 23/1820Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 157 pfu.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at unsettled to severe storm levels on day one (24 Apr), quiet to active levels on day two (25 Apr) and quiet levels on day three (26 Apr). Protons greater than 10 Mev have a chance of crossing threshold on day one (24 Apr) and have a slight chance of crossing threshold on day two (25 Apr).
III. Event probabilities 24 Apr-26 Apr
Class M 25/25/05
Class X 01/01/01
Proton 25/10/05
PCAF green
IV. Penticton 10.7 cm Flux
Observed 23 Apr 135
Predicted 24 Apr-26 Apr 135/130/125
90 Day Mean 23 Apr 159
V. Geomagnetic A Indices
Observed Afr/Ap 22 Apr 006/007
Estimated Afr/Ap 23 Apr 039/069
Predicted Afr/Ap 24 Apr-26 Apr 032/047-013/015-007/008
VI. Geomagnetic Activity Probabilities 24 Apr-26 Apr
A. Middle Latitudes
Active 25/30/15
Minor Storm 35/15/05
Major-severe storm 35/01/01
B. High Latitudes
Active 05/15/15
Minor Storm 20/30/20
Major-severe storm 79/45/20
space weather
