Viewing archive of Saturday, 3 September 2011
Solar activity report
Any mentioned solar flare in this report has a scaling factor applied by the Space Weather Prediction Center (SWPC). Because of the SWPC scaling factor, solar flares are reported as 42% smaller than for the science quality data. The scaling factor has been removed from our archived solar flare data to reflect the true physical units.
Report of Solar-Geophysical Activity 2011 Sep 03 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.comJoint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 246 Issued at 2200Z on 03 Sep 2011
IA. Analysis of Solar Active Regions and Activity from 02-2100Z to 03-2100Z
Solar activity was at low levels due to several C-class
events observed during the period. As it approached the west limb,
Region 1280 (N12W78) produced three C-class flares, the largest a
C2/Sf at 03/1736Z. Region 1281 (S19W10) produced a C2/Sf at
03/0756Z. Region 1282 (N23W52) indicated decay in its intermediate
spots, but developed a delta magnetic structure in the large leader
spot. Two new regions were numbered during the period. New Region
1286 (N20W57) rapidly emerged as an eight spot D-type group and
produced a C1 x-ray event at 03/1846Z. New Region 1287 (S30E64)
rotated onto the disk as a three spot C-type group. All remaining
regions were quiet and stable. No Earth-directed CMEs were detected
during the period.
IB. Solar Activity Forecast
Solar activity is expected to be low
for the next three days (04 - 06 September) with a slight chance for
M-class activity.
IIA. Geophysical Activity Summary 02-2100Z to 03-2100Z
The geomagnetic field was at quiet to unsettled levels with an
isolated active period observed at Boulder between 03/0900Z - 1200Z.
At about 03/0100Z, observations from the ACE spacecraft indicated an
increase in temperature, density and wind speed. These increases,
coupled with a brief period of southward Bz to -12nT and an increase
in Bt to 13nT, were indicative of a co-rotating interaction region
in advance of a coronal hole high speed stream. During the period,
wind speed increased from about 275 km/s to near 425 km/s while Bz
generally fluctuated between +/- 5 nT.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be at quiet to unsettled levels, with a chance for
isolated active periods, on day one (04 September) as the coronal
hole high speed stream (CH HSS) persists. Days two and three (05 -
06 September) will see a return to mostly quiet levels as the CH HSS
moves out of a geoeffective position.
III. Event Probabilities 04 Sep to 06 Sep
Class M | 15% | 15% | 15% |
Class X | 01% | 01% | 01% |
Proton | 01% | 01% | 01% |
PCAF | Green
|
IV. Penticton 10.7 cm Flux
Observed 03 Sep 119
Predicted 04 Sep-06 Sep 120/120/115
90 Day Mean 03 Sep 097
V. Geomagnetic A Indices
Observed Afr/Ap 02 Sep 001/003
Estimated Afr/Ap 03 Sep 011/011
Predicted Afr/Ap 04 Sep-06 Sep 008/008-005/005-005/005
VI. Geomagnetic Activity Probabilities 04 Sep to 06 Sep
A. Middle Latitudes |
Active | 20% | 15% | 10% |
Minor storm | 05% | 01% | 01% |
Major-severe storm | 01% | 01% | 01% |
B. High Latitudes |
Active | 25% | 20% | 15% |
Minor storm | 10% | 05% | 01% |
Major-severe storm | 01% | 01% | 01% |
All times in UTC
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