Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 17 April 2014

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 107 Issued at 2200Z on 17 Apr 2014

IA. Analysis of Solar Active Regions and Activity from 16/2100Z to
17/2100Z: Solar activity has been at low levels for the past 24 hours.
The largest solar event of the period was a C3 event observed at
17/1154Z. There are currently 12 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is likely to be moderate
with a slight chance for an X-class flare on days one, two, and three
(18 Apr, 19 Apr, 20 Apr).

IIA. Geophysical Activity Summary 16/2100Z to 17/2100Z: The geomagnetic
field has been at quiet to unsettled levels for the past 24 hours. Solar
wind speed, as measured by the ACE spacecraft, reached a peak speed of
448 km/s at 17/1854Z. Total IMF reached 10 nT at 17/0528Z. The maximum
southward component of Bz reached -8 nT at 17/1322Z. Electrons greater
than 2 MeV at geosynchronous orbit reached a peak level of 279 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to unsettled levels on day one (18 Apr), quiet to active
levels on day two (19 Apr) and quiet to minor storm levels on day three
(20 Apr). Protons have a slight chance of crossing threshold on days
one, two, and three (18 Apr, 19 Apr, 20 Apr).

III. Event probabilities 18 Apr-20 Apr
Class M 60/60/60
Class X 10/10/10
Proton 10/10/10
PCAF green

IV. Penticton 10.7 cm Flux
Observed 17 Apr 179
Predicted 18 Apr-20 Apr 180/180/180
90 Day Mean 17 Apr 155

V. Geomagnetic A Indices
Observed Afr/Ap 16 Apr 005/004
Estimated Afr/Ap 17 Apr 007/008
Predicted Afr/Ap 18 Apr-20 Apr 008/008-009/012-015/020

VI. Geomagnetic Activity Probabilities 18 Apr-20 Apr
A. Middle Latitudes
Active 20/40/40
Minor Storm 05/15/25
Major-severe storm 01/01/05
B. High Latitudes
Active 15/10/10
Minor Storm 25/25/25
Major-severe storm 25/55/60