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

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 113 Issued at 2200Z on 23 Apr 2017

IA.  Analysis of Solar Active Regions and Activity from 22/2100Z to
23/2100Z: Solar activity has been at very low levels for the past 24
hours. There are currently 3 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, two, and three (24 Apr, 25 Apr, 26 Apr).

IIA.  Geophysical Activity Summary 22/2100Z to 23/2100Z: The geomagnetic field has been at active to major storm levels for the past 24 hours. Solar wind speed reached a peak of 813 km/s at 23/2023Z. Total IMF reached 9 nT at 23/0406Z. The maximum southward component of Bz reached -7 nT at 23/0351Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 20544 pfu.

IIB.  Geophysical Activity Forecast: The geomagnetic field is expectd to be at active to minor storm levels on day one (24 Apr) and unsetted to minor storm levels on days two and three (25 Apr, 26 Apr).

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

IV.  Penticton 10.7 cm Flux
Observed           23 Apr 083
Predicted   24 Apr-26 Apr 084/084/084
90 Day Mean        23 Apr 078

V.  Geomagnetic A Indices
Observed Afr/Ap 22 Apr  037/061
Estimated Afr/Ap 23 Apr  030/044
Predicted Afr/Ap 24 Apr-26 Apr  023/030-015/020-015/020

VI.  Geomagnetic Activity Probabilities 24 Apr-26 Apr
A.  Middle Latitudes
Active                45/40/40
Minor Storm           25/25/25
Major-severe storm    01/01/01
B.  High Latitudes
Active                10/10/10
Minor Storm           25/25/25
Major-severe storm    65/60/60