Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 20 December 2012


Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 355 Issued at 2200Z on 20 Dec 2012

IA. Analysis of Solar Active Regions and Activity from 19/2100Z to
20/2100Z: 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 likely to be at low
levels on days one, two, and three (21 Dec, 22 Dec, 23 Dec).

IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z: 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 around 500
km/s. Total IMF reached 7.2 nT at 20/1236Z. The maximum southward
component of Bz reached -7 nT at 20/1304Z. Electrons greater than 2 MeV
at geosynchronous orbit reached a peak level of 264 pfu.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet levels on days one and two (21 Dec, 22 Dec) and at quiet
to unsettled levels on day three (23 Dec).

III. Event probabilities 21 Dec-23 Dec
Class M 05/05/05
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 20 Dec 114
Predicted 21 Dec-23 Dec 115/115/115
90 Day Mean 20 Dec 120

V. Geomagnetic A Indices
Observed Afr/Ap 19 Dec 004/004
Estimated Afr/Ap 20 Dec 005/005
Predicted Afr/Ap 21 Dec-23 Dec 006/005-006/005-006/008

VI. Geomagnetic Activity Probabilities 21 Dec-23 Dec
A. Middle Latitudes
Active 05/05/10
Minor Storm 01/01/01
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 10/10/20
Major-severe storm 05/05/10

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