Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 17 April 2013


Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 107 Issued at 2200Z on 17 Apr 2013

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
16/2132Z from Region 1719 (N09W64). There are currently 5 numbered
sunspot regions on the disk.
IB. Solar Activity Forecast: Solar activity is likely to be low with a
slight chance for an M-class flare on days one and two (18 Apr, 19 Apr)
and likely to be low on day three (20 Apr).

IIA. Geophysical Activity Summary 16/2100Z to 17/2100Z: The geomagnetic
field has been at quiet levels for the past 24 hours. Solar wind speed,
as measured by the ACE spacecraft, reached a peak speed of 379 km/s at
17/0726Z.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet levels on days one, two, and three (18 Apr, 19 Apr, 20
Apr).

III. Event probabilities 18 Apr-20 Apr
Class M 10/10/05
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 17 Apr 108
Predicted 18 Apr-20 Apr 100/100/095
90 Day Mean 17 Apr 111

V. Geomagnetic A Indices
Observed Afr/Ap 16 Apr 002/003
Estimated Afr/Ap 17 Apr 003/004
Predicted Afr/Ap 18 Apr-20 Apr 004/005-006/005-005/005

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

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