Joint USAF/NOAA Report of Solar and Geophysical Activity 11 May 2011

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 May 11 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 131 Issued at 2200Z on 11 May 2011
IA. Analysis of Solar Active Regions and Activity from 10/2100Z
to 11/2100Z: Solar activity was very low. A B8 x-ray flare occurred
at 11/0243Z, likely associated with a filament eruption between
Regions 1205 (N14W75) and 1207 (N21W51). The flare was associated
with a Type II radio sweep and a partial-halo coronal mass ejection
(CME). The CME had an estimated plane-of-sky speed of 420 km/s,
based on SOHO/LASCO images. No significant changes occurred in any
of the spotted regions. New Region 1212 (S13E46) was numbered and
was classified as a single-spot Axx region.
IB. Solar Activity Forecast: Solar activity is expected to be very
low during the period (12 – 14 May) with a chance for isolated
C-class flares.
IIA. Geophysical Activity Summary 10/2100Z to 11/2100Z:
Geomagnetic activity was at quiet to unsettled levels. ACE solar wind
data indicated Earth remained under the influence of a recurrent
coronal hole high-speed stream (CH HSS). Solar wind speeds ranged
from 352 to 414 km/sec with no discernible trend. A slight increase
in the greater than 10 MeV proton flux occurred in the wake of the
B8 flare mentioned above.
IIB. Geophysical Activity Forecast: Geomagnetic activity is
expected to be at unsettled to active levels on day 1 (12 May) with
a chance for minor storm levels as the CH HSS persists. The CME
observed late on 09 May may also disturb the field on May 12.
Activity is expected to decrease to quiet to unsettled levels on day
2 (13 May) as the CH HSS begins to subside. Activity is expected to
decrease to quiet levels on day 3 (14 May). The CME observed today
is not expected to affect the field during the forecast period.
III. Event Probabilities 12 May-14 May
Class M 10/10/10
Class X 01/01/01
Proton 01/01/01
PCAF green
IV. Penticton 10.7 cm Flux
Observed 11 May 094
Predicted 12 May-14 May 095/095/095
90 Day Mean 11 May 110
V. Geomagnetic A Indices
Observed Afr/Ap 10 May 005/008
Estimated Afr/Ap 11 May 005/005
Predicted Afr/Ap 12 May-14 May 015/015-008/010-005/005
VI. Geomagnetic Activity Probabilities 12 May-14 May
A. Middle Latitudes
Active 35/10/05
Minor storm 15/05/01
Major-severe storm 05/01/01
B. High Latitudes
Active 40/15/10
Minor storm 20/10/01
Major-severe storm 10/01/01