Joint USAF/NOAA Report of Solar and Geophysical Activity 27 May 2011 (Corrected copy)

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 May 28 0220 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
:::::::::: CORRECTED COPY ::::::::::
SDF Number 147 Issued at 2200Z on 27 May 2011
IA. Analysis of Solar Active Regions and Activity from 26/2100Z
to 27/2100Z: Solar activity was low. New Region 1226 (S18E74)
produced a B-class event and four C-class events since being
numbered today. The largest was a C5 observed at 27/1643Z. This
region began with a B1 event at 26/1654Z as it approached the
southeast limb yesterday. It is currently an H-type group, however,
the region is still rotating onto the disk and more white light area
are evident in the SDO/HMI imagery just visible on the limb. Region
1223 (S16W00) produced the only other event during the period, a B4
at 27/0953Z. This region is a Dso group with a beta magnetic
classification and grew slightly in sunspot count. Two more regions
were numbered today as Regions 1224 (N21W15) and 1225 (N18E55).
Region 1224 is a Dso group with a beta magnetic classification and
1225 is another H-type group.
IB. Solar Activity Forecast: Solar activity is expected to be low
with a chance for C-class events, and a slight chance for an M-class
event, as regions on the disk continue to evolve.
IIA. Geophysical Activity Summary 26/2100Z to 27/2100Z:
The geomagnetic field was quiet to unsettled. Observations from the
ACE spacecraft suggest the earth is under the continued influence of
the co-rotating interaction region in advance of the recurrent
coronal hole high speed stream. Solar winds have slowly increased
from around 390 to 500 km/s. The IMF Bt averaged around 8 nT with
the Bz mostly southward (-8 nT) through the period.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be predominately unsettled with occasional active
periods, including isolated minor storm conditions at high-latitudes
for day one (28 May). This is expected due to effects from the
recurrent coronal hole high speed stream (CH HSS). In addition
there are possible effects from the disappearing filament observed
on 25 May. Quiet to unsettled conditions, with isolated active
levels, are expected for days two and three (29-30 May) with
continued CH HSS effects.
III. Event Probabilities 28 May-30 May
Class M 10/10/10
Class X 01/01/01
Proton 01/01/01
PCAF green
IV. Penticton 10.7 cm Flux
Observed 27 May 090
Predicted 28 May-30 May 090/095/095
90 Day Mean 27 May 108
V. Geomagnetic A Indices
Observed Afr/Ap 26 May 004/007
Estimated Afr/Ap 27 May 010/012
Predicted Afr/Ap 28 May-30 May 015/018-010/012-008/008
VI. Geomagnetic Activity Probabilities 28 May-30 May
A. Middle Latitudes
Active 25/20/15
Minor storm 10/05/05
Major-severe storm 05/01/01
B. High Latitudes
Active 35/30/20
Minor storm 15/10/10
Major-severe storm 05/05/05