Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 18 April 2016

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 109 Issued at 2200Z on 18 Apr 2016

IA. Analysis of Solar Active Regions and Activity from 17/2100Z to 18/2100Z: Solar activity has been at high levels for the past 24 hours. The largest solar event of the period was a M6 event observed at 18/0029Z from Region 2529 (N10W67). There are currently 2 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is expected to be low with a slight chance for an M-class flare on day one (19 Apr) and expected to be very low with a chance for a C-class flares and a slight chance for an M-class flare on day two (20 Apr) and expected to be very low with a slight chance for a C-class flare on day three (21 Apr).

IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 419 km/s at 18/0051Z. Total IMF reached 12 nT at 18/0112Z. The maximum southward component of Bz reached -6 nT at 18/0744Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 207 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on day one (19 Apr), quiet to unsettled levels on day two (20 Apr) and quiet levels on day three (21 Apr). Protons greater than 10 Mev have a slight chance of crossing threshold on day one (19 Apr).

III. Event probabilities 19 Apr-21 Apr
Class M 20/10/01
Class X 05/01/01
Proton 15/05/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 18 Apr 095
Predicted 19 Apr-21 Apr 095/090/088
90 Day Mean 18 Apr 099

V. Geomagnetic A Indices
Observed Afr/Ap 17 Apr 017/021
Estimated Afr/Ap 18 Apr 007/009
Predicted Afr/Ap 19 Apr-21 Apr 010/012-008/008-006/005

VI. Geomagnetic Activity Probabilities 19 Apr-21 Apr
A. Middle Latitudes
Active 35/15/15
Minor Storm 10/10/05
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 30/20/20
Major-severe storm 45/25/20