Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 21 December 2013

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 355 Issued at 2200Z on 21 Dec 2013

IA. Analysis of Solar Active Regions and Activity from 20/2100Z to
21/2100Z: Solar activity has been at low levels for the past 24 hours.
The largest solar event of the period was a C9 event observed at
21/1036Z from Region 1928 (S17W47). There are currently 8 numbered
sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is expected to be low with
a chance for M-class flares and a slight chance for an X-class flare on
days one, two, and three (22 Dec, 23 Dec, 24 Dec).

IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z: 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 390 km/s at
21/0010Z. Total IMF reached 5 nT at 21/1333Z. The maximum southward
component of Bz reached -4 nT at 20/2122Z.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet levels on days one, two, and three (22 Dec, 23 Dec, 24
Dec).

III. Event probabilities 22 Dec-24 Dec
Class M 40/40/40
Class X 10/10/10
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 21 Dec 144
Predicted 22 Dec-24 Dec 140/135/135
90 Day Mean 21 Dec 141

V. Geomagnetic A Indices
Observed Afr/Ap 20 Dec 006/004
Estimated Afr/Ap 21 Dec 004/005
Predicted Afr/Ap 22 Dec-24 Dec 005/005-005/005-005/005

VI. Geomagnetic Activity Probabilities 22 Dec-24 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