Viewing archive of Wednesday, 18 May 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 May 18 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 138 Issued at 2200Z on 18 May 2011IA. Analysis of Solar Active Regions and Activity from 17-2100Z to 18-2100Z Solar activity has been low for the last 24 hours. New
Region 1218 (S16E66) was numbered today and produced a C1 event at
18/1259Z. Region 1208 (N09W90) produced a long duration C2 event at
18/1830Z just as it was rotating around the west limb. All other
regions on the disk remained relatively quiet and stable.
IB. Solar Activity Forecast
Solar activity is expected to remain
very low with a chance for C-class activity for the next three days
(19-21 May) as new Region 1218 continues to develop.
IIA. Geophysical Activity Summary 17-2100Z to 18-2100Z
The geomagnetic field has been mostly quiet for the last 24 hours.
Solar wind at ACE showed a decrease from approximately 550 km/s to
450 km/s during the period as effects from the coronal hole high
speed stream subside.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be quiet for the next three days (19-21 May) as the
solar wind returns to background levels.
III. Event Probabilities 19 May to 21 May
| Class M | 01% | 01% | 01% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 18 May 091 Predicted 19 May-21 May 095/095/095 90 Day Mean 18 May 109
V. Geomagnetic A Indices
Observed Afr/Ap 17 May 008/010 Estimated Afr/Ap 18 May 004/005 Predicted Afr/Ap 19 May-21 May 005/005-005/005-005/005
VI. Geomagnetic Activity Probabilities 19 May to 21 May
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 05% | 05% | 05% |
| Minor storm | 01% | 01% | 01% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 05% | 05% | 05% |
| Minor storm | 01% | 01% | 01% |
| Major-severe storm | 01% | 01% | 01% |
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