Viewing archive of Thursday, 18 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 18 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 230 Issued at 2200Z on 18 Aug 2011IA. Analysis of Solar Active Regions and Activity from 17-2100Z to 18-2100Z Solar activity was low. Both Regions 1271 (N15E38) and
1272 (S22E41) produced C1/Sf flares during the past 24 hours.
Region 1271 became more consolidated during the period, but remained
a large Ehc type spot group with beta magnetic characteristics.
IB. Solar Activity Forecast
Solar activity is expected to be low
with a chance for moderate activity. The continued persistence of
Region 1271, as well as the return of old Region 1261 on Day 2 (20
Aug), make moderate activity more probable. During the last
rotation, old Region 1261 produced five M-class events including an
M9 and CME on 04 August.
IIA. Geophysical Activity Summary 17-2100Z to 18-2100Z
The geomagnetic field was quiet and the ambient solar wind
unremarkable. The greater than 2 MeV electron flux at geosynchronous
orbit reached high levels during the period.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be predominantly quiet for the first two days of the
forecast period (19-20 Aug). A recurrent coronal hole high speed
stream is expected to become geoeffective on Day 3 (21 Aug) leading
to unsettled conditions with a chance for active periods at high
latitudes.
III. Event Probabilities 19 Aug to 21 Aug
| Class M | 45% | 45% | 45% |
| Class X | 10% | 10% | 10% |
| Proton | 01% | 01% | 01% |
| PCAF | Green | ||
IV. Penticton 10.7 cm Flux
Observed 18 Aug 098 Predicted 19 Aug-21 Aug 098/100/100 90 Day Mean 18 Aug 096
V. Geomagnetic A Indices
Observed Afr/Ap 17 Aug 006/006 Estimated Afr/Ap 18 Aug 005/005 Predicted Afr/Ap 19 Aug-21 Aug 005/005-005/005-010/012
VI. Geomagnetic Activity Probabilities 19 Aug to 21 Aug
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 05% | 10% | 20% |
| Minor storm | 01% | 05% | 05% |
| Major-severe storm | 01% | 05% | 05% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 05% | 10% | 50% |
| Minor storm | 05% | 05% | 15% |
| Major-severe storm | 01% | 01% | 10% |
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