Joint USAF/NOAA Report of Solar and Geophysical Activity 21 February 2011

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Feb 21 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 052 Issued at 2200Z on 21 Feb 2011
IA. Analysis of Solar Active Regions and Activity from 20/2100Z
to 21/2100Z: Solar activity has been low. Region 1161 (N11W42)
produced multiple C-class events and remains an E-type sunspot group
with a beta-gamma magnetic classification, while Region 1162
(N17W46) remained stable and quiet. The period’s largest x-ray event
a C7 at 21/1012Z came from Region 1158 which has rotated off the
visible disk.
IB. Solar Activity Forecast: Solar activity is expected to be low
to moderate with a slight chance for an X-class event from Region
1161 for the next three days (22-24 February).
IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z:
The geomagnetic field has been quiet to unsettled during the past 24
hours. Solar wind data from the ACE spacecraft indicated a slight
drop in velocity to around 380 km/s and sustained negative Bz of
-4nT during the period. The greater than 2 MeV electron flux at
geosynchronous orbit reached high levels during the period.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be quiet to unsettled with a slight chance for isolated
active periods during the next three days (22-24 February).
III. Event Probabilities 22 Feb-24 Feb
Class M 50/50/50
Class X 10/10/10
Proton 05/05/05
PCAF Green
IV. Penticton 10.7 cm Flux
Observed 21 Feb 097
Predicted 22 Feb-24 Feb 098/098/095
90 Day Mean 21 Feb 086
V. Geomagnetic A Indices
Observed Afr/Ap 20 Feb 006/007
Estimated Afr/Ap 21 Feb 007/008
Predicted Afr/Ap 22 Feb-24 Feb 007/008-007/008-007/008
VI. Geomagnetic Activity Probabilities 22 Feb-24 Feb
A. Middle Latitudes
Active 10/10/10
Minor storm 05/05/05
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor storm 10/10/10
Major-severe storm 01/01/01