Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 20 August 2017

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 232 Issued at 2200Z on 20 Aug 2017

IA.  Analysis of Solar Active Regions and Activity from 19/2100Z to 20/2100Z: 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 20/0152Z from Region 2672 (N05E75). There are currently 2 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 (21 Aug, 22 Aug, 23 Aug).

IIA.  Geophysical Activity Summary 19/2100Z to 20/2100Z: The geomagnetic field has been at quiet to minor storm levels for the past 24 hours. Solar wind speed reached a peak of 813 km/s at 20/0248Z. Total IMF reached 5 nT at 19/2151Z. The maximum southward component of Bz reached -4 nT at 19/2256Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 23392 pfu.

IIB.  Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on days one and two (21 Aug, 22 Aug) and quiet to unsettled levels on day three (23 Aug).

III.  Event probabilities 21 Aug-23 Aug
Class M    25/25/25
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           20 Aug 086
Predicted   21 Aug-23 Aug 090/090/090
90 Day Mean        20 Aug 076

V.  Geomagnetic A Indices
Observed Afr/Ap 19 Aug  023/028
Estimated Afr/Ap 20 Aug  020/024
Predicted Afr/Ap 21 Aug-23 Aug  014/018-011/012-008/008

VI.  Geomagnetic Activity Probabilities 21 Aug-23 Aug
A.  Middle Latitudes
Active                30/15/10
Minor Storm           10/05/01
Major-severe storm    01/01/01
B.  High Latitudes
Active                15/20/15
Minor Storm           30/30/25
Major-severe storm    45/25/20