Joint USAF/NOAA Report of Solar and Geophysical Activity 10 December 2011

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Dec 10 2200 UTC
# Prepared jointly by the U.S. Dept. of Commerce, NOAA,
# Space Weather Prediction Center and the U.S. Air Force.
#
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 344 Issued at 2200Z on 10 Dec 2011
IA. Analysis of Solar Active Regions and Activity from 09/2100Z
to 10/2100Z: Solar activity was low. Region 1375 (N09E39) produced a
C1 x-ray event at 10/0631Z. The remainder of the disk and limb was
quiet and stable.
IB. Solar Activity Forecast: Solar activity is expected to remain
at low levels with a slight chance for M-class activity all three
days of the period (11 – 13 December).
IIA. Geophysical Activity Summary 09/2100Z to 10/2100Z:
The geomagnetic field was at quiet to unsettled levels. Solar wind
velocities gradually increased through the period from 350 km/s to a
peak of near 500 km/s at about 10/1000Z. Excursions of southward
interplanetary magnetic field Bz to -10 nT were observed between
01/0200Z – 0600Z.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at quiet to unsettled levels with isolated active
periods on day one (11 December) due to effects of a recurrent
coronal hole high speed stream (CH HSS). A return to mostly quiet
conditions are expected by days two and three (12 – 13 December) as
effects from the CH HSS wane.
III. Event Probabilities 11 Dec-13 Dec
Class M 20/20/20
Class X 01/01/01
Proton 01/01/01
PCAF green
IV. Penticton 10.7 cm Flux
Observed 10 Dec 140
Predicted 11 Dec-13 Dec 140/140/140
90 Day Mean 10 Dec 146
V. Geomagnetic A Indices
Observed Afr/Ap 09 Dec 003/003
Estimated Afr/Ap 10 Dec 005/005
Predicted Afr/Ap 11 Dec-13 Dec 007/008-005/005-005/005
VI. Geomagnetic Activity Probabilities 11 Dec-13 Dec
A. Middle Latitudes
Active 15/05/05
Minor storm 01/01/01
Major-severe storm 01/01/01
B. High Latitudes
Active 20/10/10
Minor storm 05/01/01
Major-severe storm 01/01/01