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 2005

IA. 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 M25%25%25%
Class X05%05%05%
Proton05%05%05%
PCAFgreen
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
Active40%25%20%
Minor storm20%15%10%
Major-severe storm10%05%01%
B. High Latitudes
Active50%40%25%
Minor storm30%20%15%
Major-severe storm15%10%05%

All times in UTC

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