Joint USAF/NOAA Report of Solar and Geophysical Activity 01 Feb 2003


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SDF Number 032 Issued at 2200Z on 01 Feb 2003

IA. Analysis of Solar Active Regions and Activity from 31/2100Z to 01/2100Z: Solar activity was moderate during the past 24 hours. All of today's flare activity was dominated by new Region 276 (S14E76), which produced an M1 at 0905 UTC, a C9/Sf at 1954 UTC, as well as numerous additional C-class subflares. Observations of the group so far indicate a relatively small (190 millionths) D-type sunspot group. An erupting prominence was observed at 31/2200 UTC on the Northwest limb and was associated with a type II sweep (shock velocity 500 km/s) and a CME seen by LASCO. The remainder of the regions on the disk were quiet and stable.

IB. Solar Activity Forecast: Solar activity is expected to be low to moderate. Region 276 is expected to be the main driver of activity, and has a fair chance for producing an additional M-class event over the next three days.

IIA. Geophysical Activity Summary 31/2100Z to 01/2100Z: The geomagnetic field ranged from quiet to active levels during the past 24 hours. Quiet conditions prevailed for most of the day, but an increase to unsettled to active began at 1500 UTC. A marked increase in solar wind velocity and total magnetic field strength was observed beginning at 1300 UTC, but a predominantly positive value for Bz suppressed activity until 1900 UTC, when Bz turned weakly southwards. The interpretation of the enhanced solar wind flow is not obvious, but seems most consistent with the passage of transient flow due to the halo CME that occurred on 30 January. The great than 2 MeV electron fluxes reached high levels during the past 24 hours.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be mostly active for the next 24 hours with a chance for some isolated minor storm periods. Conditions should subside to unsettled to active by day two, and return to mostly unsettled levels by the third day.

III. Event Probabilities 02 Feb-04 Feb

  • Class M 35/35/35
  • Class X 05/05/05
  • Proton 01/01/01
  • PCAF green

IV. Penticton 10.7 cm Flux

  • Observed 01 Feb 126
  • Predicted 02 Feb-04 Feb 130/135/140
  • 90 Day Mean 01 Feb 156

V. Geomagnetic A Indices

  • Observed Afr/Ap 31 Jan 011/018
  • Estimated Afr/Ap 01 Feb 012/015
  • Predicted Afr/Ap 02 Feb-04 Feb 025/025-015/020-010/015

VI. Geomagnetic Activity Probabilities 02 Feb-04 Feb A. Middle Latitudes

  • Active 35/30/25
  • Minor storm 30/20/15
  • Major-severe storm 15/05/01

B. High Latitudes

  • Active 35/35/20
  • Minor storm 40/30/10
  • Major-severe storm 20/10/05

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