Viewing archive of Thursday, 11 August 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 Aug 11 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 223 Issued at 2200Z on 11 Aug 2011IA. Analysis of Solar Active Regions and Activity from 10-2100Z to 11-2100Z Solar activity was low. Region 1263 (N17, L=301)
produced a C6 x-ray flare from beyond the west limb. New regions
1269 (S22E17) and 1270 (S23E54) were numbered today; both are small
and magnetically simple. A CME was observed on the west limb,
evident in SOHO/LASCO C2 imagery at 11/1036Z. Material movement and
subsequent darkening was observed in STEREO-A EUV imagery beginning
at approximately 11/1005Z. This CME is not expected to be
geoeffective.
IB. Solar Activity Forecast
Solar activity is expected to be very
low to low. There is a chance for a C class x-ray event throughout
the period.
IIA. Geophysical Activity Summary 10-2100Z to 11-2100Z
The geomagnetic field was quiet. Solar wind speed at the ACE
spacecraft continued to decline and ended the period near 400 km/s.
The Phi angle briefly switched to negative between 11/10Z and
11/12Z. The Bz component of the interplanetary magnetic field
remained around zero. A shock was observed in the STEREO-A beacon
data at roughly 11/0600Z. This is most likely the arrival of the 09
August CME from Region 1263. The greater than 2 MeV electron flux at
geosynchronous orbit was at high levels throughout the period.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be predominantly quiet for the next three days (12-14
August).
III. Event Probabilities 12 Aug to 14 Aug
| Class M | 05% | 05% | 05% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | Green | ||
IV. Penticton 10.7 cm Flux
Observed 11 Aug 084 Predicted 12 Aug-14 Aug 085/085/090 90 Day Mean 11 Aug 096
V. Geomagnetic A Indices
Observed Afr/Ap 10 Aug 008/007 Estimated Afr/Ap 11 Aug 005/004 Predicted Afr/Ap 12 Aug-14 Aug 005/005-005/005-005/005
VI. Geomagnetic Activity Probabilities 12 Aug to 14 Aug
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 15% | 05% | 05% |
| Minor storm | 05% | 05% | 05% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 20% | 10% | 20% |
| Minor storm | 10% | 05% | 10% |
| Major-severe storm | 05% | 01% | 05% |
All times in UTC
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