Viewing archive of Saturday, 28 May 2005
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 2005 May 28 2210 UTC# Prepared jointly by the U.S. Dept. of Commerce, NOAA, #Space Environment Center and the U.S. Air Force. #
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 148 Issued at 2200Z on 28 May 2005IA. Analysis of Solar Active Regions and Activity from 27-2100Z to 28-2100Z Solar activity was low. Region 767 (S08W16) was
responsible for two C-class flares. The largest was a C5 flare at
28/0230 UTC. Growth in this region has slowed over the summary
period. At 28/1726 UTC a C1 flare was produced by a region behind
the east limb at approximately S08.
IB. Solar Activity Forecast
Solar activity is expected to be low
to moderate. Region 767, still has the potential to produce low
level M-class flares.
IIA. Geophysical Activity Summary 27-2100Z to 28-2100Z
The geomagnetic field was quiet to active. Active periods are due to
the effects of a recurrent coronal hole high speed stream. At
approximately 28/0330 UTC a Co-rotating Interaction Region (CIR) was
observed at ACE preceding the coronal hole high speed stream. Solar
wind speed at ACE increased from approximately 275 km/s to 550 km/s
by the end of the summary period. The greater than 2 MeV electron
flux at geosynchronous orbit was high again today.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be at active to minor storm levels with isolated major
storm conditions at higher latitudes on 29 May. Heightened activity
is due to the combined effects of a coronal hole high speed stream,
and the influence of the CMEs from Region 767 observed on 26 May.
Activity will diminish to quiet to unsettled levels by 31 May.
III. Event Probabilities 29 May to 31 May
| Class M | 25% | 25% | 25% |
| Class X | 05% | 05% | 05% |
| Proton | 05% | 05% | 05% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 28 May 092 Predicted 29 May-31 May 095/100/100 90 Day Mean 28 May 092
V. Geomagnetic A Indices
Observed Afr/Ap 27 May 001/004 Estimated Afr/Ap 28 May 012/020 Predicted Afr/Ap 29 May-31 May 020/020-015/015-008/010
VI. Geomagnetic Activity Probabilities 29 May to 31 May
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 40% | 25% | 20% |
| Minor storm | 20% | 15% | 10% |
| Major-severe storm | 10% | 05% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 50% | 40% | 25% |
| Minor storm | 30% | 20% | 15% |
| Major-severe storm | 15% | 10% | 05% |
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