Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 28 May 2017

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 148 Issued at 2200Z on 28 May 2017

IA.  Analysis of Solar Active Regions and Activity from 27/2100Z to 28/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C3 event observed at 28/1928Z from Region 2659 (N13W70). There are currently 1 numbered sunspot regions on the disk.

IB.  Solar Activity Forecast: Solar activity is expected to be very low with a chance for a C-class flares on days one and two (29 May, 30 May) and expected to be very low with a slight chance for a C-class flare on day three (31 May).

IIA.  Geophysical Activity Summary 27/2100Z to 28/2100Z: The geomagnetic field has been at quiet to severe storm levels for the past 24 hours. Solar wind speed reached a peak of 463 km/s at 27/2243Z. Total IMF reached 23 nT at 27/2222Z. The maximum southward component of Bz reached -20 nT at 27/2222Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 641 pfu.

IIB.  Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on day one (29 May) and quiet levels on days two and three (30 May, 31 May).

III.  Event probabilities 29 May-31 May
Class M    05/05/01
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           28 May 079
Predicted   29 May-31 May 078/072/070
90 Day Mean        28 May 076

V.  Geomagnetic A Indices
Observed Afr/Ap 27 May  014/017
Estimated Afr/Ap 28 May  036/060
Predicted Afr/Ap 29 May-31 May  012/012-005/005-005/005

VI.  Geomagnetic Activity Probabilities 29 May-31 May
A.  Middle Latitudes
Active                20/10/10
Minor Storm           05/01/01
Major-severe storm    01/01/01
B.  High Latitudes
Active                15/15/15
Minor Storm           20/15/15
Major-severe storm    15/10/10