Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 145 Issued at 2200Z on 25 May 2023

IA. Analysis of Solar Active Regions and Activity from 24/2100Z to 25/2100Z: 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 25/1446Z from Region 3312 (S24W12). There are currently 6 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 (26 May, 27 May, 28 May).

IIA. Geophysical Activity Summary 24/2100Z to 25/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 689 km/s at 25/1050Z. Total IMF reached 6 nT at 25/1134Z. The maximum southward component of Bz reached -6 nT at 25/1135Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 3826 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on day one (26 May), quiet to unsettled levels on day two (27 May) and quiet levels on day three (28 May).

III. Event probabilities 26 May-28 May
Class M 35/35/35
Class X 05/05/05
Proton 05/05/05
PCAF green

IV. Penticton 10.7 cm Flux
Observed 25 May 152
Predicted 26 May-28 May 150/155/155
90 Day Mean 25 May 153

V. Geomagnetic A Indices
Observed Afr/Ap 24 May 010/010
Estimated Afr/Ap 25 May 012/012
Predicted Afr/Ap 26 May-28 May 013/015-008/008-005/005

VI. Geomagnetic Activity Probabilities 26 May-28 May
A. Middle Latitudes
Active 35/20/10
Minor Storm 15/05/05
Major-severe storm 01/01/01
B. High Latitudes
Active 10/20/15
Minor Storm 30/25/20
Major-severe storm 50/25/15

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