Joint USAF/NOAA Report of Solar and Geophysical Activity 15 Apr 2004
Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.
Updated 2004 Apr 15 2210 UTC
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 106 Issued at 2200Z on 15 Apr 2004
IA. Analysis of Solar Active Regions and Activity from 14/2100Z
to 15/2100Z: Solar activity increased to moderate levels. Activity
consisted of low level B-class flares until Region 591 (S16W38)
produced an impulsive M1/Sf flare at 15/1644Z. This region remains
a magnetic beta-gamma-delta configuration although the delta
structure seen in the dominant lead polarity spot appears very weak.
It also continues to display reverse polarity characteristics. The
remainder of the active regions were quiescent during the period.
No new regions were numbered today.
IB. Solar Activity Forecast: Solar activity is expected to be at
low levels. Region 591 has the potential of producing isolated low
level M-class flares.
IIA. Geophysical Activity Summary 14/2100Z to 15/2100Z:
The geomagnetic field was at quiet levels today. The greater than 2
MeV electron flux reached high levels today.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at quiet to unsettled levels throughout the period.
III. Event Probabilities 16 Apr-18 Apr
- Class M 30/30/30
- Class X 01/01/01
- Proton 01/01/01
- PCAF green
IV. Penticton 10.7 cm Flux
- Observed 15 Apr 097
- Predicted 16 Apr-18 Apr 095/100/100
- 90 Day Mean 15 Apr 108
V. Geomagnetic A Indices
- Observed Afr/Ap 14 Apr 002/005
- Estimated Afr/Ap 15 Apr 001/006
- Predicted Afr/Ap 16 Apr-18 Apr 004/010-006/010-006/010
VI. Geomagnetic Activity Probabilities 16 Apr-18 Apr
A. Middle Latitudes
- Active 10/15/15
- Minor storm 01/05/05
- Major-severe storm 01/01/01
B. High Latitudes
- Active 20/20/20
- Minor storm 05/05/05
- Major-severe storm 01/01/01
