Status Report

Joint USAF/NOAA Report of Solar and Geophysical Activity 6 August 2011

By SpaceRef Editor
August 6, 2011
Filed under , , ,

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Aug 06 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 218 Issued at 2200Z on 06 Aug 2011
IA. Analysis of Solar Active Regions and Activity from 05/2100Z
to 06/2100Z: Solar activity was low. The largest event of the
period was a C4/Sf flare from Region 1267 (S17E13). This region
developed a small delta in the central spot. Region 1263, an Ekc
spot class with a Beta-Gamma-Delta magnetic configuration, lost some
penumbral area in its central spots, however it developed new spots
as flux began to emerge from its trailer area. SOHO/LASCO C2
imagery observed two slow moving CMEs at 1036Z and 1736Z with the
majority of the ejecta directed off the West limb. SDO and SXI
imagery showed filament eruptions associated with the events. These
CMEs are not expected to be geoeffective.
IB. Solar Activity Forecast: Solar activity is expected to be low
with the continued chance for an M-class flare from Region 1263.
IIA. Geophysical Activity Summary 05/2100Z to 06/2100Z:
The geomagnetic field was at quiet to severe storm levels. Minor to
severe storm periods were seen from 05/2100Z to 06/0600Z. The
period started off with solar wind speeds reaching approximately 620
km/s with a total field strength around 28 nT. The Bz component of
the magnetic field was south around -20 nT for 2 hours before
crossing into a positive region at approximately 05/2211Z. Solar
wind speed, density, and total magnetic field strength slowly
decreased throughout the period as the effects of the CME passage
began to diminish. The period ended with a wind speed around 440
km/s and Bt around 5 nT. The greater than 10 MeV protons above 10
PFU event that began at 04/0635Z, reached a peak flux of 96 PFU at
05/2150Z, and ended at 06/0515Z.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be unsettled to active on 07 August as a recurrent
coronal hole high speed stream is expected to become geoeffective.
Levels are expected to decrease to quiet to unsettled on 08 August.
Mostly quiet conditions are expected on 09 August.
III. Event Probabilities 07 Aug-09 Aug
Class M 45/45/35
Class X 10/10/05
Proton 10/10/05
PCAF green
IV. Penticton 10.7 cm Flux
Observed 06 Aug 110
Predicted 07 Aug-09 Aug 105/100/095
90 Day Mean 06 Aug 096
V. Geomagnetic A Indices
Observed Afr/Ap 05 Aug 032/049
Estimated Afr/Ap 06 Aug 018/033
Predicted Afr/Ap 07 Aug-09 Aug 015/015-008/010-005/005
VI. Geomagnetic Activity Probabilities 07 Aug-09 Aug
A. Middle Latitudes
Active 25/10/05
Minor storm 15/05/01
Major-severe storm 05/01/01
B. High Latitudes
Active 25/15/05
Minor storm 20/05/01
Major-severe storm 15/01/01

SpaceRef staff editor.