Viewing archive of Wednesday, 17 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 17 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 229 Issued at 2200Z on 17 Aug 2011IA. Analysis of Solar Active Regions and Activity from 16-2100Z to 17-2100Z Solar activity was low. Both Regions 1271 (N16E50) and
1272 (S19E55) produced C-class events during the summary period.
The largest was a C3 from Region 1271 at 17/1119Z. Region 1271
ended the period as an Esi type spot group with beta-gamma-delta
magnetic characteristics. New Region 1273 (S18W03) was numbered
today and classified as a Bxo type spot group with simple beta
magnetic characteristics. A CME from Region 1272 was observed in
SOHO/LASCO C2 imagery at 17/0248Z with a plane-of-sky speed of about
550 km/s. This CME is not expected to be geoeffective.
IB. Solar Activity Forecast
Solar activity is expected to be low.
Continued C-class events are expected from Regions 1271 and 1272,
There is a slight chance for an M-class event given the increasing
size and complexity of Region 1271.
IIA. Geophysical Activity Summary 16-2100Z to 17-2100Z
The geomagnetic field was quiet to unsettled. Wind speed at the ACE
spacecraft continued to decline through the summary period, ending
near 420 km/s.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be mostly quiet for the next three days (18-20 August).
III. Event Probabilities 18 Aug to 20 Aug
| Class M | 15% | 15% | 15% |
| Class X | 01% | 05% | 05% |
| Proton | 01% | 01% | 01% |
| PCAF | Green | ||
IV. Penticton 10.7 cm Flux
Observed 17 Aug 098 Predicted 18 Aug-20 Aug 098/100/100 90 Day Mean 17 Aug 096
V. Geomagnetic A Indices
Observed Afr/Ap 16 Aug 006/008 Estimated Afr/Ap 17 Aug 008/008 Predicted Afr/Ap 18 Aug-20 Aug 005/005-005/005-005/005
VI. Geomagnetic Activity Probabilities 18 Aug to 20 Aug
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 10% | 05% | 10% |
| Minor storm | 01% | 01% | 05% |
| Major-severe storm | 00% | 00% | 05% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 20% | 05% | 20% |
| Minor storm | 05% | 05% | 05% |
| Major-severe storm | 05% | 01% | 05% |
All times in UTC
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