Joint USAF/NOAA Report of Solar and Geophysical Activity 3 August 2011

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Aug 03 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 215 Issued at 2200Z on 03 Aug 2011
IA. Analysis of Solar Active Regions and Activity from 02/2100Z
to 03/2100Z: Solar activity was high. Region 1261 (N16W37) produced
the largest event of the period, an M6/2B flare at 03/1348Z. It was
accompanied by a 10cm radio burst (180 sfu), Type II (812 km/s) and
IV emissions. A CME was subsequently observed in STEREO-A COR2
imagery at 03/1409Z. Time-height extrapolation from LASCO C3
imagery indicated a speed of 624 km/s. Region 1263 (N17W06) also
produced an M1/1F flare at 03/0432Z. Both regions were classified
as Dki type spot groups with beta-gamma and beta-gamma-delta
magnetic characteristics respectively. A weak CME was also observed
in STEREO-A COR2 imagery at approximately 03/0109Z but was not
expected to be geoeffective.
IB. Solar Activity Forecast: Solar activity is likely to remain
moderate to high for the next three days (04-06 Aug) under the
continued threat of a major event. Regions 1261 and 1263 are most
likely to produce activity.
IIA. Geophysical Activity Summary 02/2100Z to 03/2100Z:
The geomagnetic field was predominantly quiet. Wind speeds at the
ACE spacecraft were near 360 km/s and Bz was near zero. A slight
enhancement in 10 MeV protons was observed at both ACE and the
GOES-13 satellite, but remained below alert thresholds.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be mostly quiet on day 1 (04 Aug), becoming active on
days 2 and 3 (05-06 Aug), with a slight chance of minor to major
storms at high latitudes. The increased geomagnetic activity is
associated with the arrivals of CME’s from 02 and 03 August. The 10
MeV protons are likely to exceed the 10 pfu threshold with CME
passage.
III. Event Probabilities 04 Aug-06 Aug
Class M 65/65/60
Class X 10/10/10
Proton 15/55/55
PCAF green
IV. Penticton 10.7 cm Flux
Observed 03 Aug 120
Predicted 04 Aug-06 Aug 120/120/115
90 Day Mean 03 Aug 096
V. Geomagnetic A Indices
Observed Afr/Ap 02 Aug 003/003
Estimated Afr/Ap 03 Aug 003/003
Predicted Afr/Ap 04 Aug-06 Aug 005/005-020/025-018/020
VI. Geomagnetic Activity Probabilities 04 Aug-06 Aug
A. Middle Latitudes
Active 05/40/25
Minor storm 01/10/05
Major-severe storm 01/05/01
B. High Latitudes
Active 05/40/40
Minor storm 01/15/15
Major-severe storm 01/05/05