Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 21 September 2017

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 264 Issued at 2200Z on 21 Sep 2017

IA.  Analysis of Solar Active Regions and Activity from 20/2100Z to 21/2100Z: Solar activity has been at very low levels for the past 24 hours. There are currently 2 numbered sunspot regions on the disk.

IB.  Solar Activity Forecast: Solar activity is expected to be very low with a slight chance for a C-class flare on day one (22 Sep) and likely to be low with a slight chance for an M-class flare on days two and three (23 Sep, 24 Sep).

IIA.  Geophysical Activity Summary 20/2100Z to 21/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 472 km/s at 21/0212Z. Total IMF reached 5 nT at 21/2058Z. The maximum southward component of Bz reached -4 nT at 21/1723Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 30386 pfu.

IIB.  Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet levels on day one (22 Sep), quiet to unsettled levels on day two (23 Sep) and quiet to active levels on day three (24 Sep).

III.  Event probabilities 22 Sep-24 Sep
Class M    01/15/15
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           21 Sep 073
Predicted   22 Sep-24 Sep 070/085/090
90 Day Mean        21 Sep 081

V.  Geomagnetic A Indices
Observed Afr/Ap 20 Sep  008/009
Estimated Afr/Ap 21 Sep  007/007
Predicted Afr/Ap 22 Sep-24 Sep  006/005-007/008-009/012

VI.  Geomagnetic Activity Probabilities 22 Sep-24 Sep
A.  Middle Latitudes
Active                10/20/25
Minor Storm           01/05/10
Major-severe storm    01/01/01
B.  High Latitudes
Active                15/15/15
Minor Storm           20/25/25
Major-severe storm    15/30/40