Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 208 Issued at 2200Z on 27 Jul 2023

IA. Analysis of Solar Active Regions and Activity from 26/2100Z to 27/2100Z: Solar activity has been at moderate levels for the past 24 hours. The largest solar event of the period was a M1 event observed at 27/0951Z from Region 3376 (N22W96). There are currently 11 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 (28 Jul, 29 Jul, 30 Jul).

IIA. Geophysical Activity Summary 26/2100Z to 27/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 548 km/s at 26/2307Z. Total IMF reached 7 nT at 27/0232Z. The maximum southward component of Bz reached -2 nT at 27/1038Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 661 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet levels on days one and two (28 Jul, 29 Jul) and quiet to active levels on day three (30 Jul).

III. Event probabilities 28 Jul-30 Jul
Class M 35/25/25
Class X 05/01/01
Proton 05/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 27 Jul 165
Predicted 28 Jul-30 Jul 165/162/158
90 Day Mean 27 Jul 164

V. Geomagnetic A Indices
Observed Afr/Ap 26 Jul 023/024
Estimated Afr/Ap 27 Jul 010/011
Predicted Afr/Ap 28 Jul-30 Jul 006/005-006/005-012/015

VI. Geomagnetic Activity Probabilities 28 Jul-30 Jul
A. Middle Latitudes
Active 10/10/25
Minor Storm 01/01/10
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/20
Minor Storm 15/15/25
Major-severe storm 10/10/20

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