Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 109 Issued at 2200Z on 19 Apr 2023
IA. Analysis of Solar Active Regions and Activity from 18/2100Z to 19/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C3 event observed at 19/0841Z from Region 3272 (S24W88). 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 (20 Apr, 21 Apr, 22 Apr).
IIA. Geophysical Activity Summary 18/2100Z to 19/2100Z: The geomagnetic field has been at quiet to active levels for the past 24 hours. Solar wind speed reached a peak of 615 km/s at 18/2144Z. Total IMF reached 9 nT at 19/2054Z. The maximum southward component of Bz reached -7 nT at 19/1025Z. 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 unsettled to minor storm levels on day one (20 Apr) and quiet to active levels on days two and three (21 Apr, 22 Apr).
III. Event probabilities 20 Apr-22 Apr
Class M 35/35/35
Class X 01/01/01
Proton 01/01/01
PCAF green
IV. Penticton 10.7 cm Flux
Observed 19 Apr 147
Predicted 20 Apr-22 Apr 145/140/135
90 Day Mean 19 Apr 162
V. Geomagnetic A Indices
Observed Afr/Ap 18 Apr 009/013
Estimated Afr/Ap 19 Apr 016/021
Predicted Afr/Ap 20 Apr-22 Apr 019/024-015/016-014/016
VI. Geomagnetic Activity Probabilities 20 Apr-22 Apr
A. Middle Latitudes
Active 40/25/30
Minor Storm 20/10/10
Major-severe storm 01/01/01
B. High Latitudes
Active 10/15/15
Minor Storm 25/25/25
Major-severe storm 60/35/40
space weather
