Report of Solar-Geophysical Activity

Issued: 2011 Mar 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 087 Issued at 2200Z on 28 Mar 2011

IA.  Analysis of Solar Active Regions and Activity from  27/2100Z
to 28/2100Z:  Solar activity was at low levels. Region 1181 (S26E31)
produced a C1/Sf flare at 27/2326Z while Region 1176 (S17W11)
produced a C1 X-ray event at 28/1139Z. Region 1176 decayed in area
and spot count, but maintained a complex beta-gamma magnetic
configuration. Region 1183 (N15E54) indicated growth in area and
spot count as it continued to rotate onto the disk. At 28/1405Z, a
filament eruption was observed in STEREO-B EUVI 195 near N20, L=030.
Associated with this eruption was a CME that lifted off the NE limb,
first observed in LASCO C3 imagery at 28/1818Z. Due to the source of
this CME, it is not Earth-directed. No new regions were numbered
during the period.
IB.  Solar Activity Forecast:  Solar activity is expected to be low
all three days of the forecast period (29 - 31 March). A chance
exists all three days for isolated M-class activity.
IIA.  Geophysical Activity Summary 27/2100Z to 28/2100Z:
The geomagnetic field was quiet. ACE solar wind velocities remained
low and steady, only varying between 340 km/s to 370 km/s. The Bz
component of the IMF ranged between +/- 4 nT.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be quiet for day one (29 March). By days two and three
(30 - 31 March), quiet to unsettled conditions, with isolated active
periods, are expected due to the arrival of a recurrent coronal hole
high speed stream.
III.  Event Probabilities 29 Mar-31 Mar
Class M    35/50/50
Class X    01/05/05
Proton     01/01/01
PCAF       green
IV.  Penticton 10.7 cm Flux
Observed           28 Mar 119
Predicted   29 Mar-31 Mar  120/130/135
90 Day Mean        28 Mar 097
V.  Geomagnetic A Indices
Observed Afr/Ap 27 Mar  002/002
Estimated Afr/Ap 28 Mar  002/002
Predicted Afr/Ap 29 Mar-31 Mar  005/005-010/010-010/010
VI.  Geomagnetic Activity Probabilities 29 Mar-31 Mar
A.  Middle Latitudes
Active                10/20/20
Minor storm           01/05/05
Major-severe storm    01/01/01
B.  High Latitudes
Active                15/25/25
Minor storm           01/10/10
Major-severe storm    01/01/01

NOAA Space Weather Scale descriptions can be found at www.sec.noaa.gov/NOAAscales