Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 169 Issued at 2200Z on 18 Jun 2023

IA. Analysis of Solar Active Regions and Activity from 17/2100Z to 18/2100Z: Solar activity has been at moderate levels for the past 24 hours. The largest solar event of the period was a M2 event observed at 18/1353Z from Region 3336 (S22E17). 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 and a slight chance for an X-class flare on days one, two, and three (19 Jun, 20 Jun, 21 Jun).

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 526 km/s at 17/2112Z. Total IMF reached 6 nT at 18/1710Z. The maximum southward component of Bz reached -5 nT at 18/1714Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 3835 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on days one and two (19 Jun, 20 Jun) and quiet to unsettled levels on day three (21 Jun). Protons have a slight chance of crossing threshold on days one, two, and three (19 Jun, 20 Jun, 21 Jun).

III. Event probabilities 19 Jun-21 Jun
Class M 40/40/40
Class X 10/10/10
Proton 10/10/10
PCAF green

IV. Penticton 10.7 cm Flux
Observed 18 Jun 164
Predicted 19 Jun-21 Jun 160/155/160
90 Day Mean 18 Jun 153

V. Geomagnetic A Indices
Observed Afr/Ap 17 Jun 008/008
Estimated Afr/Ap 18 Jun 009/008
Predicted Afr/Ap 19 Jun-21 Jun 011/012-010/012-008/010

VI. Geomagnetic Activity Probabilities 19 Jun-21 Jun
A. Middle Latitudes
Active 25/25/15
Minor Storm 10/10/05
Major-severe storm 05/05/01
B. High Latitudes
Active 10/10/15
Minor Storm 20/20/20
Major-severe storm 35/35/20

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