Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 17 December 2012


Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 352 Issued at 2200Z on 17 Dec 2012

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 C1 event observed at
17/0220Z from Region 1629 (N13W88). There are currently 5 numbered
sunspot regions on the disk.
IB. Solar Activity Forecast: Solar activity is expected to be at low
levels with a slight chance for M-class flares on days one, two, and
three (18 Dec, 19 Dec, 20 Dec).

IIA. Geophysical Activity Summary 16/2100Z to 17/2100Z: The geomagnetic
field has been at quiet to active levels for the past 24 hours. Solar
wind speed, as measured by the ACE spacecraft, reached a peak speed of
532 km/s at 17/1237Z. Total IMF reached 9.6 nT at 17/0740Z. The maximum
southward component of Bz reached -7.4 nT at 17/1102Z. Electrons greater
than 2 MeV at geosynchronous orbit reached a peak level of 155 pfu.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to active levels on day one (18 Dec) and a return to
predominantly quiet levels for days two and three (19 Dec and 20 Dec).

III. Event probabilities 18 Dec-20 Dec
Class M 15/15/15
Class X 01/01/01
Proton 05/05/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 17 Dec 115
Predicted 18 Dec-20 Dec 120/125/125
90 Day Mean 17 Dec 120

V. Geomagnetic A Indices
Observed Afr/Ap 16 Dec 005/006
Estimated Afr/Ap 17 Dec 010/012
Predicted Afr/Ap 18 Dec-20 Dec 012/012-008/010-005/005

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

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