Viewing archive of Friday, 17 June 2005

Solar activity report

Report of Solar-Geophysical Activity 2005 Jun 17 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 168 Issued at 2200Z on 17 Jun 2005

IA. Analysis of Solar Active Regions and Activity from 16-2100Z to 17-2100Z

Solar activity is expected to be low. Newly numbered Region 780 (S07E66) produced the only C-class activity of the period, a C1 flare at 17/1904Z. Active Regions 775 (N10, L=055) and 776 (S05, L=046) have both rotated around the west limb. A post CME loop system on the west limb persisted through the early part of this period following yesterday's M4 proton flare from Region 775. Region 779 (S18W19) continues to slowly grow and is now an E-type beta-gamma spot group; however, no activity of note occurred.
IB. Solar Activity Forecast
Solar activity is expected to be low. C-class flares are possible from Regions 779 and 780.
IIA. Geophysical Activity Summary 16-2100Z to 17-2100Z
The geomagnetic field was quiet to active. The most disturbed conditions occurred early in the period during intervals of sustained southward Bz. Solar wind speed decreased from over 650 km/s to under 550 km/s by the end of the period. The elevated solar wind conditions are due to the combined effects of CME transient flow and a high speed coronal hole stream. A greater than 100 MeV proton event began at 16/2125Z following yesterday's M4 flare. The event ended at 17/0730Z with a peak flux of 2.9 pfu at 16/2315Z. A greater than 10 MeV proton event began at 16/2200Z, peaked at 17/0500Z at 44 pfu, and ended at 17/1805Z. The greater than 2 MeV electron flux at geosynchronous orbit was at high levels again today.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to range from quiet to minor storm levels. Elevated solar wind speed is expected to produce occasional active conditions on 18 June. It is unlikely that much of the ejecta associated with yesterday's M4 flare and CME is Earth directed; however, a glancing blow may create active to minor storm periods on 19 June. Quiet to unsettled levels are expected on 20 June. The greater than 10 and greater than 100 MeV protons are expected to return to background levels over the next day.
III. Event Probabilities 18 Jun to 20 Jun
Class M10%10%10%
Class X01%01%01%
IV. Penticton 10.7 cm Flux
  Observed       17 Jun 091
  Predicted   18 Jun-20 Jun  090/090/090
  90 Day Mean        17 Jun 093
V. Geomagnetic A Indices
  Observed Afr/Ap 16 Jun  019/026
  Estimated     Afr/Ap 17 Jun  015/014
  Predicted    Afr/Ap 18 Jun-20 Jun  012/015-015/020-010/012
VI. Geomagnetic Activity Probabilities 18 Jun to 20 Jun
A. Middle Latitudes
Minor storm10%15%05%
Major-severe storm05%05%01%
B. High Latitudes
Minor storm15%20%10%
Major-severe storm05%10%05%

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