Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 144 Issued at 2200Z on 24 May 2023

IA. Analysis of Solar Active Regions and Activity from 23/2100Z to 24/2100Z: 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 24/1721Z from Region 3311 (N18W08). 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 day one (25 May) and expected to be low with a chance for M-class flares and a slight chance for an X-class flare on days two and three (26 May, 27 May).

IIA. Geophysical Activity Summary 23/2100Z to 24/2100Z: The geomagnetic field has been at quiet to active levels for the past 24 hours. Solar wind speed reached a peak of 636 km/s at 23/2130Z. Total IMF reached 5 nT at 24/1606Z. The maximum southward component of Bz reached -5 nT at 23/2108Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 2693 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on days one and two (25 May, 26 May) and quiet to unsettled levels on day three (27 May). Protons greater than 10 Mev have a slight chance of crossing threshold on day three (27 May).

III. Event probabilities 25 May-27 May
Class M 30/40/45
Class X 05/10/10
Proton 05/05/10
PCAF green

IV. Penticton 10.7 cm Flux
Observed 24 May 164
Predicted 25 May-27 May 160/160/165
90 Day Mean 24 May 153

V. Geomagnetic A Indices
Observed Afr/Ap 23 May 011/012
Estimated Afr/Ap 24 May 012/017
Predicted Afr/Ap 25 May-27 May 010/012-013/015-008/008

VI. Geomagnetic Activity Probabilities 25 May-27 May
A. Middle Latitudes
Active 35/35/20
Minor Storm 20/15/05
Major-severe storm 05/01/01
B. High Latitudes
Active 20/10/20
Minor Storm 30/30/25
Major-severe storm 30/50/25

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