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

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Jun 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 172 Issued at 2200Z on 21 Jun 2011
IA. Analysis of Solar Active Regions and Activity from 20/2100Z
to 21/2100Z: Solar activity was low. Today’s activity consisted of a
long-duration C7 X-ray event which began at 0122Z, reached maximum
at 0325Z and ended at 0427Z. The X-ray event was associated with a
Sf flare from Region 1236 (N17W21) as well as the eruption of a 17
degree filament near N39W01. Also associated with this activity was
a symmetric halo CME which first entered the SOHO C2 coronagraph
field of view at 0316Z and had an estimated plane of sky speed of
about 640 km/s. Region 1236 was generally unchanged during the past
24 hours and is the dominant spot group on the disk. The other
spotted regions were very small and appeared to be decaying.
IB. Solar Activity Forecast: Solar activity is expected to be low
for the next three days.
IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z:
The geomagnetic field was quiet to unsettled during the past 24
hours. Solar wind observations from the ACE spacecraft indicate a
solar sector boundary crossing between 1200 and 1500Z (positive to
negative).
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be quiet for the next 36-42 hours. An increase is
expected beginning sometime late on day 2 (23 June) and continuing
through day 3 (24 June). Geomagnetic activity is expected to be
mostly active during this time period, with a chance for minor storm
periods at mid-latitudes, and minor to major storm periods at high
latitudes. The increase in activity is forecast due to expected
combined effects from today’s halo CME event and a favorably
positioned coronal hole.
III. Event Probabilities 22 Jun-24 Jun
Class M 05/05/05
Class X 01/01/01
Proton 01/01/01
PCAF green
IV. Penticton 10.7 cm Flux
Observed 21 Jun 095
Predicted 22 Jun-24 Jun 095/095/095
90 Day Mean 21 Jun 104
V. Geomagnetic A Indices
Observed Afr/Ap 20 Jun 007/007
Estimated Afr/Ap 21 Jun 007/008
Predicted Afr/Ap 22 Jun-24 Jun 005/005-018/018-025/035
VI. Geomagnetic Activity Probabilities 22 Jun-24 Jun
A. Middle Latitudes
Active 05/25/30
Minor storm 01/30/30
Major-severe storm 01/15/20
B. High Latitudes
Active 05/20/25
Minor storm 01/35/35
Major-severe storm 01/25/30