Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 77 Issued at 2200Z on 18 Mar 2023

IA. Analysis of Solar Active Regions and Activity from 17/2100Z to 18/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C9 event observed at 18/0716Z from Region 3256 (S22E66). There are currently 3 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 (19 Mar, 20 Mar, 21 Mar).

IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 472 km/s at 18/0334Z. Total IMF reached 6 nT at 18/1556Z. The maximum southward component of Bz reached -5 nT at 18/0339Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 198 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on day one (19 Mar) and quiet to active levels on days two and three (20 Mar, 21 Mar).

III. Event probabilities 19 Mar-21 Mar
Class M 25/25/25
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 18 Mar 140
Predicted 19 Mar-21 Mar 138/138/138
90 Day Mean 18 Mar 170

V. Geomagnetic A Indices
Observed Afr/Ap 17 Mar 007/006
Estimated Afr/Ap 18 Mar 008/009
Predicted Afr/Ap 19 Mar-21 Mar 006/005-011/015-015/018

VI. Geomagnetic Activity Probabilities 19 Mar-21 Mar
A. Middle Latitudes
Active 15/30/35
Minor Storm 01/15/15
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 20/30/30
Major-severe storm 20/45/50

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