Viewing archive of Thursday, 15 July 2004

Solar activity report

Report of Solar-Geophysical Activity 2004 Jul 15 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 197 Issued at 2200Z on 15 Jul 2004

IA. Analysis of Solar Active Regions and Activity from 14-2100Z to 15-2100Z

Analysis of Solar Active Regions and Activity from 14/2100Z to 15/2100Z: Solar activity was high. Region 649 (S10E40) produced two impulsive X-class flares: an X1 at 0141 UTC and an X1 at 1824 UTC. Both of these events originated near the delta configuration in the dominant trailer spot. Although the spot is not large, the close proximity of opposite polarity spots is creating an area of strong magnetic gradients. There was also some magnetic flux emergence to the south of this spot during the past 24 hours. Both of the events were compact and bright. LASCO coronagraph data did not show a CME in association with the first X1 event. As of forecast issue time the LASCO data seemed to indicate a slow, relatively faint CME off the east limb in association with the second X1 event.
IB. Solar Activity Forecast
Solar activity is expected to be moderate to high, with Region 649 as the dominant source for activity. Additional M-class flares are expected and there is a fair chance for additional major flare activity out of 649, especially if magnetic flux continues to emerge.
IIA. Geophysical Activity Summary 14-2100Z to 15-2100Z
The geomagnetic field was quiet to unsettled during the past 24 hours.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be mostly unsettled tomorrow (16 July) with a chance for some isolated active periods at higher latitudes. Conditions should be predominantly unsettled for the 2nd and 3rd days (17-18 July).
III. Event Probabilities 16 Jul to 18 Jul
Class M75%75%75%
Class X30%30%30%
IV. Penticton 10.7 cm Flux
  Observed       15 Jul 146
  Predicted   16 Jul-18 Jul  140/140/140
  90 Day Mean        15 Jul 098
V. Geomagnetic A Indices
  Observed Afr/Ap 14 Jul  006/009
  Estimated     Afr/Ap 15 Jul  007/010
  Predicted    Afr/Ap 16 Jul-18 Jul  012/020-010/012-008/010
VI. Geomagnetic Activity Probabilities 16 Jul to 18 Jul
A. Middle Latitudes
Minor storm15%15%10%
Major-severe storm05%05%05%
B. High Latitudes
Minor storm15%15%10%
Major-severe storm05%05%05%

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