Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 133 Issued at 2200Z on 13 May 2023

IA. Analysis of Solar Active Regions and Activity from 12/2100Z to 13/2100Z: 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 13/0045Z from Region 3296 (N15W89). There are currently 8 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 (14 May, 15 May, 16 May).

IIA. Geophysical Activity Summary 12/2100Z to 13/2100Z: The geomagnetic field has been at quiet to active levels for the past 24 hours. Solar wind speed reached a peak of 574 km/s at 12/2201Z. Total IMF reached 15 nT at 13/1953Z. The maximum southward component of Bz reached -14 nT at 13/1950Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 361 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on day one (14 May), quiet levels on day two (15 May) and unsettled to active levels on day three (16 May). Protons greater than 10 Mev have a slight chance of crossing threshold on day one (14 May).

III. Event probabilities 14 May-16 May
Class M 35/35/35
Class X 10/10/10
Proton 10/05/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 13 May 144
Predicted 14 May-16 May 145/140/135
90 Day Mean 13 May 157

V. Geomagnetic A Indices
Observed Afr/Ap 12 May 015/017
Estimated Afr/Ap 13 May 009/011
Predicted Afr/Ap 14 May-16 May 008/008-005/005-011/014

VI. Geomagnetic Activity Probabilities 14 May-16 May
A. Middle Latitudes
Active 15/10/20
Minor Storm 05/05/05
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 20/20/20
Major-severe storm 20/15/20

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