Viewing archive of Sunday, 4 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 04 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.comJoint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 247 Issued at 2200Z on 04 Sep 2011
IA. Analysis of Solar Active Regions and Activity from 03-2100Z to 04-2100Z
Solar activity was at moderate levels due to an M3
x-ray event observed on the west limb at 04/1145Z. This event
originated from the west limb spot group complex consisting of
Regions 1280 (N13W91) and 1286 (N20W75). Close proximity to the limb
made precise analysis of the flare location difficult. Associated
with the M3 event was a west limb CME, first observed in LASCO C2
imagery at 04/1212Z. A plane-of-sky speed was estimated at about 400
km/s. Preceding this event was another west limb CME, first observed
in LASCO C2 imagery at 04/0912Z. A plane-of-sky speed was estimated
at about 150 km/s. Analysis of the potential geoeffectiveness of
these CMEs is ongoing. Numerous C-class flares were also observed
during the period from this area of the west limb. Region 1287
(S32E51) produced a C1 x-ray event early in the period at 03/2212Z.
This region showed minor growth in area while the remaining regions
on the disk indicated a slight decay in area coupled with loss of
spots.
IB. Solar Activity Forecast
Solar activity is expected to be low
for the next three days (05 - 07 September). A chance for additional
M-class activity exists through 06 September.
IIA. Geophysical Activity Summary 03-2100Z to 04-2100Z
The geomagnetic field was at quiet to unsettled levels. Observations
from the ACE spacecraft indicated wind speeds varied predominately
between 350 to 400 km/s. The Bz component of the interplanetary
magnetic field did not vary much beyond +/- 5 nT during the period.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be at quiet to unsettled levels for day one (05
September) due to continuing effects from a coronal hole high speed
stream (CH HSS). By days two and three (06 - 07 September), the
field is expected to be at mostly quiet levels as the CH HSS moves
out of a geoeffective position.
III. Event Probabilities 05 Sep to 07 Sep
Class M | 25% | 15% | 05% |
Class X | 01% | 01% | 01% |
Proton | 01% | 01% | 01% |
PCAF | Green
|
IV. Penticton 10.7 cm Flux
Observed 04 Sep 119
Predicted 05 Sep-07 Sep 120/115/105
90 Day Mean 04 Sep 098
V. Geomagnetic A Indices
Observed Afr/Ap 03 Sep 009/013
Estimated Afr/Ap 04 Sep 007/008
Predicted Afr/Ap 05 Sep-07 Sep 005/008-005/005-005/005
VI. Geomagnetic Activity Probabilities 05 Sep to 07 Sep
A. Middle Latitudes |
Active | 15% | 10% | 10% |
Minor storm | 01% | 01% | 01% |
Major-severe storm | 01% | 01% | 01% |
B. High Latitudes |
Active | 20% | 15% | 15% |
Minor storm | 05% | 01% | 01% |
Major-severe storm | 01% | 01% | 01% |
All times in UTC
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