Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 043 Issued at 2200Z on 12 Feb 2012
IA. Analysis of Solar Active Regions and Activity from 11/2100Z
to 12/2100Z: Solar activity was low due to multiple C-class events
from new Region 1419 (N28E77) which rotated onto the disk as a
C-type group. This new spot group heralds the return of old Region
1402. New Region 1418 (S24E18) evolved on the disk as a B-type
group while new Region 1420 (S13E77) rotated onto the disk as an
H-type group. Region 1416 (S19W15) elongated along its axis and was
classified as an E-type Beta group. No Earth-directed CMEs were
observed during the period.
IB. Solar Activity Forecast: Solar activity is expected to be low
with a chance for M-class activity, and a slight chance for X-class
activity, for the next three days (13 - 15 February).
IIA. Geophysical Activity Summary 11/2100Z to 12/2100Z:
The geomagnetic field was at quiet levels. ACE solar wind speeds
were steady through the period at about 340 km/s. The Bz component
of the interplanetary magnetic field was mostly north with a 3-hour
period of southward Bz (-5 nT) from about 12/0600 - 0900Z. During
this 3-hour period, the phi angle switched from a positive (away) to
a negative (toward) orientation.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at quiet to unsettled levels on day one (13 February)
due to coronal hole high speed stream effects. Late on day one and
through day two (14 February), field activity is expected to
increase to unsettled to active levels, with high latitude minor
storm intervals. This increase in activity is due to anticipated
effects from the 10 February CME. Day three (15 February) will see
a return of mostly quiet to unsettled levels as CME effects subside.
III. Event Probabilities 13 Feb-15 Feb
Class M 50/50/50
Class X 10/10/10
Proton 01/01/01
PCAF green
IV. Penticton 10.7 cm Flux
Observed 12 Feb 110
Predicted 13 Feb-15 Feb 120/125/130
90 Day Mean 12 Feb 134
V. Geomagnetic A Indices
Observed Afr/Ap 11 Feb 003/004
Estimated Afr/Ap 12 Feb 004/005
Predicted Afr/Ap 13 Feb-15 Feb 011/012-014/018-006/008
VI. Geomagnetic Activity Probabilities 13 Feb-15 Feb
A. Middle Latitudes
Active 35/40/20
Minor storm 15/20/10
Major-severe storm 01/05/01
B. High Latitudes
Active 40/50/30
Minor storm 20/30/15
Major-severe storm 05/10/01
