Joint USAF/NOAA Report of Solar and Geophysical Activity 01 Nov 2004


Prepared jointly by the U.S. Dept. of Commerce, NOAA, Space Environment Center and the U.S. Air Force.

Updated 2004 Nov 01 2210 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity SDF Number 306 Issued at 2200Z on 01 Nov 2004

IA. Analysis of Solar Active Regions and Activity from 31/2100Z to 01/2100Z: Solar activity was moderate. Region 691 (N13W55) produced today's only M-class flare: an M1/1f at 0322 UTC. The event was associated with a type II sweep and a relatively slow CME off the west limb (plane-of-sky speed ~ 500-550 km/s). Region 691 showed steady decay during the past 24 hours. The most spectacular event of the period was a bright CME from a source behind the west limb, which was first observed in the LASCO C2 coronagraph at 0606 UTC. The absence of disk signatures and observations in EIT 195 imagery clearly indicate a backside source. The plane-of-sky speed of the CME was about 800 km/s. Region 693 (S16E08) grew considerably during the period and is the dominant region on the disk. Although the group shows occasional brightenings it still has not produced any flare activity. New Region 696 (N09E63) was assigned today as a small, D-type group.

IB. Solar Activity Forecast: Solar activity is expected to be moderate, but there is a continued slight chance for major flares or proton producing flares from 691 or 693.

IIA. Geophysical Activity Summary 31/2100Z to 01/2100Z: The geomagnetic field was quiet to unsettled during the past 24 hours. The arrival of transient flow from the solar events of 30 October has not yet been observed in the solar wind data. Proton events at greater than 10 MeV and greater than 100 MeV were observed. The 10 MeV event began at 0655 UTC, reached a maximum of 63 PFU at 0805 UTC, and appears to have ended as of 1900 UTC. The 100 MeV event began at 0635 UTC, reached a maximum of 1.5 PFU at 0645 UTC, and ended at 0755 UTC. The event was well associated with the backside CME reported in part IA.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be predominantly active for the next 24 hours (02 November) as the impact from the solar events of 30 October is still expected. Conditions should decline to unsettled to slightly active for 03 November, and should be predominantly unsettled by 04 November.

III. Event Probabilities 02 Nov-04 Nov

  • Class M 50/50/50
  • Class X 15/15/15
  • Proton 15/15/15
  • PCAF yellow

IV. Penticton 10.7 cm Flux

  • Observed 01 Nov 136
  • Predicted 02 Nov-04 Nov 135/135/130
  • 90 Day Mean 01 Nov 107

V. Geomagnetic A Indices

  • Observed Afr/Ap 31 Oct 007/010
  • Estimated Afr/Ap 01 Nov 012/015
  • Predicted Afr/Ap 02 Nov-04 Nov 020/025-015/015-010/010

VI. Geomagnetic Activity Probabilities 02 Nov-04 Nov

A. Middle Latitudes

  • Active 30/25/20
  • Minor storm 25/20/15
  • Major-severe storm 15/10/05

B. High Latitudes

  • Active 35/30/25
  • Minor storm 30/25/20
  • Major-severe storm 20/10/05

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