Viewing archive of Sunday, 17 July 2005

Solar activity report

Report of Solar-Geophysical Activity 2005 Jul 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 198 Issued at 2200Z on 17 Jul 2005

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

Activity was at low levels today. Region 790 (S10W93) produced the largest flare during the period, a very impulsive C4 flare which occurred at 17/0629Z. This region also produced multiple B-class flares as it began rotating beyond the solar west limb. Spotless Region 789 (N17W86) was responsible for producing several B-class flares today. A back-sided full halo CME, which is believed to be from old Region 786 (N12 L=056), was first observed on LASCO C2 imagery at 17/1130Z. No new regions were numbered today.
IB. Solar Activity Forecast
Solar activity is expected to be at very low to low levels.
IIA. Geophysical Activity Summary 16-2100Z to 17-2100Z
The geomagnetic field ranged from quiet to minor storm levels. A weak transient signature (likely from the X1 related CME activity seen on 14 July) was detected at the ACE spacecraft near 17/0000Z where the wind speeds increased from near 425 km/sec to 500 km/sec. Minor storming was later observed between 17/0900 and 1200Z. The greater than 10 MeV proton event that began on 14/0245Z, had a peak flux of 134 pfu at 15/0345Z, and underwent an injection of flux at 17/1735Z allowing for the event to remain in-progress at near 17 pfu at the time of this writing. The source believed responsible for the increase in proton flux was the back-sided activity relating to the full halo CME mentioned in 1A.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be at predominantly quiet to unsettled levels on 18 and 19 July. A recurrent high speed coronal hole stream is expected to become geoeffective 20 July with active to minor storming expected and isolated major storm conditions possible. The greater than 10 proton event is expected to end on 18 July.
III. Event Probabilities 18 Jul to 20 Jul
Class M15%05%01%
Class X01%01%01%
IV. Penticton 10.7 cm Flux
  Observed       17 Jul 074
  Predicted   18 Jul-20 Jul  075/075/075
  90 Day Mean        17 Jul 097
V. Geomagnetic A Indices
  Observed Afr/Ap 16 Jul  010/009
  Estimated     Afr/Ap 17 Jul  010/020
  Predicted    Afr/Ap 18 Jul-20 Jul  005/015-008/012-020/025
VI. Geomagnetic Activity Probabilities 18 Jul to 20 Jul
A. Middle Latitudes
Minor storm05%05%20%
Major-severe storm01%01%15%
B. High Latitudes
Minor storm20%15%35%
Major-severe storm05%05%15%

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