Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 90 Issued at 2200Z on 31 Mar 2023

IA. Analysis of Solar Active Regions and Activity from 30/2100Z to 31/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C4 event observed at 31/0909Z from Region 3260 (N24W85). There are currently 5 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is expected to be low with a slight chance for an M-class flare on day one (01 Apr) and likely to be low on days two and three (02 Apr, 03 Apr).

IIA. Geophysical Activity Summary 30/2100Z to 31/2100Z: The geomagnetic field has been at quiet to minor storm levels for the past 24 hours. Solar wind speed reached a peak of 692 km/s at 31/0346Z. Total IMF reached 9 nT at 31/0307Z. The maximum southward component of Bz reached -7 nT at 31/0258Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 1162 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on day one (01 Apr) and quiet to unsettled levels on days two and three (02 Apr, 03 Apr).

III. Event probabilities 01 Apr-03 Apr
Class M 15/01/01
Class X 05/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 31 Mar 129
Predicted 01 Apr-03 Apr 130/125/125
90 Day Mean 31 Mar 171

V. Geomagnetic A Indices
Observed Afr/Ap 30 Mar 011/013
Estimated Afr/Ap 31 Mar 014/020
Predicted Afr/Ap 01 Apr-03 Apr 011/012-007/008-008/008

VI. Geomagnetic Activity Probabilities 01 Apr-03 Apr
A. Middle Latitudes
Active 35/15/30
Minor Storm 15/10/10
Major-severe storm 01/01/01
B. High Latitudes
Active 10/15/15
Minor Storm 25/15/25
Major-severe storm 50/20/40

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