Status Report

Joint USAF/NOAA Report of Solar and Geophysical Activity 09 Apr 2004

By SpaceRef Editor
April 9, 2004
Filed under , ,

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

Updated 2004 Apr 09 2210 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 100 Issued at 2200Z on 09 Apr 2004

IA. Analysis of Solar Active Regions and Activity from 08/2100Z
to 09/2100Z: Solar activity continued at low levels. Region 588
(S15W26) produced the only activity of note this period – a C2 flare
at 09/2040Z. This region underwent considerable decay in the past 24
hours, however, it still maintains a reverse polarity beta magnetic
configuration. This is now the only region with visible sunspots.
The remainder of the disk and limb was quiet.

IB. Solar Activity Forecast: Solar activity is expected to be very
low to low. Region 588 is in decay but maintains potential for
isolated C-class activity.

IIA. Geophysical Activity Summary 08/2100Z to 09/2100Z:
The geomagnetic field ranged from quiet to minor storming. The
interplanetary shock associated with the 6 April CME impacted the
ACE spacecraft at 09/0147Z. Solar wind speed increased from 450 km/s
to near 570 km/s, and the IMF Bz component turned southward for some
short periods following the shock arrival. The storm was short-lived
with active to minor storm levels ending by 09/0900Z. The greater
than 2 MeV electron flux at geosynchronous orbit reached high levels

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to range from quiet to minor storm levels. The CME
associated with the C7 flare on 08/1017Z is expected to impact the
geomagnetic field late on 10 April. In response, active to minor
storm conditions are expected on 10 and 11 April. Quiet to unsettled
levels with isolated active periods are expected on 12 April.

III. Event Probabilities 10 Apr-12 Apr

  • Class M 05/05/10
  • Class X 01/01/01
  • Proton 01/01/01
  • PCAF green

IV. Penticton 10.7 cm Flux

  • Observed 09 Apr 090
  • Predicted 10 Apr-12 Apr 090/095/100
  • 90 Day Mean 09 Apr 110

V. Geomagnetic A Indices

  • Observed Afr/Ap 08 Apr 016/016
  • Estimated Afr/Ap 09 Apr 015/018
  • Predicted Afr/Ap 10 Apr-12 Apr 020/025-020/025-010/015

VI. Geomagnetic Activity Probabilities 10 Apr-12 Apr

A. Middle Latitudes

  • Active 40/40/25
  • Minor storm 30/30/05
  • Major-severe storm 15/15/01

B. High Latitudes

  • Active 45/45/30
  • Minor storm 35/35/10
  • Major-severe storm 20/20/05

SpaceRef staff editor.