Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 18 December 2012


Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 353 Issued at 2200Z on 18 Dec 2012

IA. Analysis of Solar Active Regions and Activity from 17/2100Z to
18/2100Z: 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
18/1308Z from Region 1631 (N23W89). There are currently 4 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 (19 Dec, 20 Dec, 21 Dec).

IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z: 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 547 km/s at
18/0822Z. Total IMF reached 8.8 nT at 18/0213Z. The maximum southward
component of Bz reached -6.6 nT at 17/2319Z. Electrons greater than 2
MeV at geosynchronous orbit reached a peak level of 481 pfu.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet levels for the next three days (19 Dec, 20 Dec, 21 Dec).

III. Event probabilities 19 Dec-21 Dec
Class M 15/15/15
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 18 Dec 116
Predicted 19 Dec-21 Dec 115/115/115
90 Day Mean 18 Dec 120

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

VI. Geomagnetic Activity Probabilities 19 Dec-21 Dec
A. Middle Latitudes
Active 05/05/05
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 05/05/05

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