Joint USAF/NOAA Report of Solar and Geophysical Activity 06 Apr 2004
Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.
Updated 2004 Apr 06 2210 UTC
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 097 Issued at 2200Z on 06 Apr 2004
IA. Analysis of Solar Active Regions and Activity from 05/2100Z
to 06/2100Z: Solar activity has been moderate. Region 588 (S15E14)
produced an M2.4/Sf flare at 06/1328 UTC. A full-halo CME was
observed on LASCO imagery erupting from the sun shortly after the
flare, with an estimated speed of 1050 km/s. The CME was not
directed towards Earth, but may provide a glancing blow to the
geomagnetic field. No significant development was observed from
active regions on the visible disk, and no new regions were numbered
today.
IB. Solar Activity Forecast: Solar activity is expected to be low.
Region 588 may produce C- and isolated M-class flares.
IIA. Geophysical Activity Summary 05/2100Z to 06/2100Z:
The geomagnetic field has been at quiet to minor storm conditions.
After increasing early in the period, the solar wind speed has
leveled off at about 575 km/s. The greater than 2 MeV electrons
hovered at the high threshold for most of the day, and ended the
period below the threshold.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at quiet to active conditions all three days under
the continued influence of a high speed solar wind stream associated
with a coronal hole in geoeffective position. Minor storm
conditions are expected on day two (8 April) due to the potential
effects from two recent CMEs. Although neither appeared to be
directed toward Earth, the CME associated with the M1.7 flare that
occurred on 5 April and the CME associated with today’s M2.4 flare
should both arrive early on 8 April and may come close enough to
Earth’s geomagnetic field to cause minor storming.
III. Event Probabilities 07 Apr-09 Apr
- Class M 25/25/25
- Class X 01/01/01
- Proton 01/01/01
- PCAF green
IV. Penticton 10.7 cm Flux
- Observed 06 Apr 101
- Predicted 07 Apr-09 Apr 105/105/100
- 90 Day Mean 06 Apr 110
V. Geomagnetic A Indices
- Observed Afr/Ap 05 Apr 009/014
- Estimated Afr/Ap 06 Apr 018/026
- Predicted Afr/Ap 07 Apr-09 Apr 015/020-025/030-015/020
VI. Geomagnetic Activity Probabilities 07 Apr-09 Apr
A. Middle Latitudes
- Active 30/40/30
- Minor storm 20/25/20
- Major-severe storm 10/20/10
B. High Latitudes
- Active 30/30/30
- Minor storm 35/30/35
- Major-severe storm 25/35/30
