Viewing archive of Wednesday, 28 July 2004

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 2004 Jul 28 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 210 Issued at 2200Z on 28 Jul 2004

IA. Analysis of Solar Active Regions and Activity from 27-2100Z to 28-2100Z

Solar activity has declined to low levels. Region 652 (N08W76) continues to be quite active and produced several C-class events this period. The most important was a very long duration C4 enhancement that began around 28/0200Z and lasted for 10 hours. LASCO imagery showed a large CME off the west limb originating from near Region 652. Though most of the ejecta was westward directed, a glancing blow is possible from this CME. Region 652 continues to slowly decay, but still maintains considerable size and magnetic complexity. No other significant changes were noted.
IB. Solar Activity Forecast
Solar activity is expected to be very low to moderate. Region 652 still has potential for an M-class flare before it rotates around the west limb on 29 July. Expect levels to decrease to very low to low by 30 July.
IIA. Geophysical Activity Summary 27-2100Z to 28-2100Z
The geomagnetic field ranged from quiet to minor storm levels. The period began with minor storm levels in the waning stages of yesterday's severe geomagnetic storm. By 28/0300Z, the IMF Bz was near zero and the geomagnetic field responded with quiet to unsettled conditions for the remainder of the period. Solar wind speed was elevated near 900 km/s at the beginning of the period, but gradually declined to 600 km/s. The greater than 10 MeV proton event that began on 25/1855Z, ended on 28/0040Z. The greater than 2 MeV electron flux at geosynchronous orbit was at very high levels today.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be quiet to unsettled on 29 July. Today's CME off the southwest limb is expected to produce unsettled to minor storm periods late on 30 July. A gradual return to quiet to unsettled conditions is expected on 31 July.
III. Event Probabilities 29 Jul to 31 Jul
Class M40%20%05%
Class X10%05%01%
IV. Penticton 10.7 cm Flux
  Observed       28 Jul 101
  Predicted   29 Jul-31 Jul  090/080/080
  90 Day Mean        28 Jul 106
V. Geomagnetic A Indices
  Observed Afr/Ap 27 Jul  119/162
  Estimated     Afr/Ap 28 Jul  012/015
  Predicted    Afr/Ap 29 Jul-31 Jul  012/015-020/030-015/020
VI. Geomagnetic Activity Probabilities 29 Jul to 31 Jul
A. Middle Latitudes
Minor storm10%15%10%
Major-severe storm01%05%05%
B. High Latitudes
Minor storm15%20%15%
Major-severe storm05%10%05%

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