Joint USAF/NOAA Report of Solar and Geophysical Activity 28 December 2011

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Dec 28 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 362 Issued at 2200Z on 28 Dec 2011
IA. Analysis of Solar Active Regions and Activity from 27/2100Z
to 28/2100Z: Solar activity has been at low levels for the past 24
hours. Region 1386 (S18E08), Region 1387 (S21W70) and New Region
1389 (S20E70) have all produced C-class events, the largest being
from Region 1389, which was a C7/1F flare at 1425Z. Region 1386 and
1387 both continue to grow and evolve, but have yet to produce
major solar activity. Several small non-Earth directed CME’s were
observed during the summary period.
IB. Solar Activity Forecast: Solar activity is expected to be at
low to moderate levels for the next three days (29 – 31 December).
IIA. Geophysical Activity Summary 27/2100Z to 28/2100Z:
The geomagnetic field has been at quiet levels for the past 24 hours.
Signatures observed by the ACE spacecraft indicate the arrival of a
small CME around 0950Z. Solar wind speeds increased from around 250
km/s to 280 km/s with and increase in the total IMF to around 14 nT.
This transient appears to be from an unknown event, perhaps on 24
December. The lower energetic particle sensors on the ACE spacecraft
continue to gradually increase, indicating another approaching CME.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at quiet to active levels with a chance for isolated
minor storm levels on day one (29 December) as multiple CME’s are
expected to arrive. Quiet to unsettled level are expected on day two
(30 December) as effects the previous CME’s wane. Predominantly
quiet levels are expected on day three (31 December).
III. Event Probabilities 29 Dec-31 Dec
Class M 40/40/40
Class X 01/01/01
Proton 10/10/10
PCAF Green
IV. Penticton 10.7 cm Flux
Observed 28 Dec 145
Predicted 29 Dec-31 Dec 145/140/140
90 Day Mean 28 Dec 144
V. Geomagnetic A Indices
Observed Afr/Ap 27 Dec 002/001
Estimated Afr/Ap 28 Dec 003/004
Predicted Afr/Ap 29 Dec-31 Dec 015/022-012/012-005/005
VI. Geomagnetic Activity Probabilities 29 Dec-31 Dec
A. Middle Latitudes
Active 25/15/01
Minor storm 10/05/01
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor storm 25/20/10
Major-severe storm 20/20/01