Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 23 August 2017

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 235 Issued at 2200Z on 23 Aug 2017

IA.  Analysis of Solar Active Regions and Activity from 22/2100Z to 23/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C2 event observed at 23/1343Z from Region 2672 (N08E34). There are currently 2 numbered sunspot regions on the disk.

IB.  Solar Activity Forecast: Solar activity is likely to be low with a slight chance for an M-class flare on days one, two, and three (24 Aug, 25 Aug, 26 Aug).

IIA.  Geophysical Activity Summary 22/2100Z to 23/2100Z: The geomagnetic field has been at unsettled to minor storm levels for the past 24 hours. Solar wind speed reached a peak of 510 km/s at 23/1755Z. Total IMF reached 7 nT at 23/0942Z. The maximum southward component of Bz reached -6 nT at 23/1655Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 3710 pfu.

IIB.  Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on day one (24 Aug), quiet to unsettled levels on day two (25 Aug) and quiet levels on day three (26 Aug).

III.  Event probabilities 24 Aug-26 Aug
Class M    15/15/15
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           23 Aug 085
Predicted   24 Aug-26 Aug 085/085/085
90 Day Mean        23 Aug 076

V.  Geomagnetic A Indices
Observed Afr/Ap 22 Aug  016/023
Estimated Afr/Ap 23 Aug  018/025
Predicted Afr/Ap 24 Aug-26 Aug  011/014-007/008-006/005

VI.  Geomagnetic Activity Probabilities 24 Aug-26 Aug
A.  Middle Latitudes
Active                35/15/10
Minor Storm           15/05/01
Major-severe storm    01/01/01
B.  High Latitudes
Active                15/15/15
Minor Storm           25/20/15
Major-severe storm    35/15/15