Status Report

Joint USAF/NOAA Report of Solar and Geophysical Activity 26 Apr 2008

By SpaceRef Editor
April 26, 2008
Filed under , , ,

Product: Report of Solar-Geophysical Activity
Issued: 2008 Apr 26 2200 UTC
Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Weather Prediction Center and the U.S. Air Force.

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 117 Issued at 2200Z on 26 Apr 2008

IA. Analysis of Solar Active Regions and Activity from 25/2100Z to 26/2100Z: Solar activity was very low. The solar disk is void of spots. Nonetheless there was a B3/Sf flare at 1408Z from an unnumbered area of spotless plage near N08E09. The flare was associated with a wave that was visible in EUV imagery on STEREO and SOHO, type II and type IV radio sweeps, as well as a slow, faint, full halo CME visible in coronagraph imagery. The estimated plane of sky speed for the CME was around 430-480 km/s.

IB. Solar Activity Forecast: Solar activity is expected to be very low.

IIA. Geophysical Activity Summary 25/2100Z to 26/2100Z: The geomagnetic field was quiet to unsettled during the past 24 hours. Solar wind speed remains somewhat elevated (around 460-500 km/s) and density very low (around 1 p/cc), consistent with the decaying phase of a high speed stream. The greater than 2 MeV electron flux at geosynchronous orbit was high during the past 24 hours.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be predominantly quiet for the next two days (27-28 April). A small increase is expected late on the third day (29 April) in response to today’s CME event: activity is expected to be unsettled with a chance for isolated active periods after the disturbance arrives.

III. Event Probabilities 27 Apr-29 Apr

  • Class M 01/01/01
  • Class X 01/01/01
  • Proton 01/01/01
  • PCAF Green

IV. Penticton 10.7 cm Flux

  • Observed 26 Apr 069
  • Predicted 27 Apr-29 Apr 070/070/070
  • 90 Day Mean 26 Apr 071

V. Geomagnetic A Indices

  • Observed Afr/Ap 25 Apr 007/008
  • Estimated Afr/Ap 26 Apr 007/008
  • Predicted Afr/Ap 27 Apr-29 Apr 005/005-005/005-007/008

VI. Geomagnetic Activity Probabilities 27 Apr-29 Apr

A. Middle Latitudes

  • Active 10/10/20
  • Minor storm 05/05/10
  • Major-severe storm 01/01/01

B. High Latitudes

  • Active 10/10/25
  • Minor storm 05/05/10
  • Major-severe storm 01/01/05

SpaceRef staff editor.