Viewing archive of Saturday, 17 August 2002

Solar activity report

Report of Solar-Geophysical Activity 2002 Aug 17 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 229 Issued at 2200Z on 17 Aug 2002

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

Solar activity was at moderate levels. Region 69 (S07W03) has produced three M-class events, the largest an M3.4/Sf at 17/2051 UTC. Other activity from this region has been a number of C-class events and numerous sub-flares. Region 69 continues to grow in area and spot count at 1950 millionths and 58 spots, and is exhibiting multiple magnetic delta configurations within the same penumbra. Region 79 (S21E18) has shown growth particularly in spot count. Two new regions were numbered today: Region 82 (N21E06) and Region 83 (S18E67).
IB. Solar Activity Forecast
Solar activity is expected to be moderate to high. Region 69 has the potential to produce a major event.
IIA. Geophysical Activity Summary 16-2100Z to 17-2100Z
The geomagnetic field was at quiet to unsettled condition with one three-hour period of isolated active levels at 17/0900 UTC. Greater than 2 MeV electron flux at geosynchronous orbit exceeded event threshold at 17/1405 UTC, reached a peak value of 1350 pfu at 17/1710 UTC and decreased below threshold levels at 17/1845 UTC. NASA/ACE data indicates that the solar wind velocities decreased throughout the day from a peak velocity of 600 km/s to around 450 km/s due to waning coronal hole effects.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be at minor to major storm levels on day one of the forecast period. A shock arrival from the M5/full halo CME event on 16 August is expected early on day one. The geomagnetic field for day two and three of the forecast period is expected to be at quiet to unsettled levels.
III. Event Probabilities 18 Aug to 20 Aug
Class M75%75%75%
Class X20%20%20%
IV. Penticton 10.7 cm Flux
  Observed       17 Aug 227
  Predicted   18 Aug-20 Aug  230/235/235
  90 Day Mean        17 Aug 167
V. Geomagnetic A Indices
  Observed Afr/Ap 16 Aug  008/017
  Estimated     Afr/Ap 17 Aug  012/012
  Predicted    Afr/Ap 18 Aug-20 Aug  050/070-018/020-012/015
VI. Geomagnetic Activity Probabilities 18 Aug to 20 Aug
A. Middle Latitudes
Minor storm30%15%10%
Major-severe storm20%05%05%
B. High Latitudes
Minor storm30%15%10%
Major-severe storm20%10%05%

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