Joint USAF/NOAA Report of Solar and Geophysical Activity 07 Apr 2004
Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.
Updated 2004 Apr 07 2210 UTC
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 098 Issued at 2200Z on 07 Apr 2004
IA. Analysis of Solar Active Regions and Activity from 06/2100Z
to 07/2100Z: Solar activity has been very low. Solar x-ray flux
remained at background levels throughout the period. Region 588
(S17E01) maintained its size, and is now in a beta-gamma magnetic
configuration. New Region 590 (S09W71) was numbered today.
IB. Solar Activity Forecast: Solar activity is expected to be very
low to low. Region 588 still has the potential to produce C-and
isolated M-class flares.
IIA. Geophysical Activity Summary 06/2100Z to 07/2100Z:
The geomagnetic field has been quiet to unsettled. Solar wind speed
at ACE began a steady decline at 06/2300 UTC and is now at
approximately 450 km/s. The greater than 2 MeV electron flux at
geosynchronous orbit reached high levels today.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be quiet to active, with periods of minor storm
conditions possible on day one and two (8-9 April). Two CMEs,
associated with solar flares on 6 and 7 April, may cause activity in
Earth’s geomagnetic field. Geomagnetic activity should subside to
unsettled levels on day three (10 April).
III. Event Probabilities 08 Apr-10 Apr
- Class M 20/20/20
- Class X 01/01/01
- Proton 01/01/01
- PCAF green
IV. Penticton 10.7 cm Flux
- Observed 07 Apr 098
- Predicted 08 Apr-10 Apr 105/105/100
- 90 Day Mean 07 Apr 110
V. Geomagnetic A Indices
- Observed Afr/Ap 06 Apr 017/021
- Estimated Afr/Ap 07 Apr 010/010
- Predicted Afr/Ap 08 Apr-10 Apr 025/030-015/020-010/015
VI. Geomagnetic Activity Probabilities 08 Apr-10 Apr
A. Middle Latitudes
- Active 40/40/30
- Minor storm 25/20/20
- Major-severe storm 20/10/10
B. High Latitudes
- Active 35/35/35
- Minor storm 35/30/25
- Major-severe storm 30/25/20
