Joint USAF/NOAA Report of Solar and Geophysical Activity 20 Oct 2004
Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.
Updated 2004 Oct 20 2210 UTC
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 294 Issued at 2200Z on 20 Oct 2004
IA. Analysis of Solar Active Regions and Activity from 19/2100Z
to 20/2100Z: Solar activity increased to moderate levels. Region
687 (N10E65) produced the largest flare of the period, an M2 x-ray
flare that occurred at 20/1051Z. A CME was observed in LASCO
imagery which does not appear to be Earth directed. This region
remains too close to the eastern limb to fully discern magnetic
complexity, although it does appear to contain a compact cluster of
sunspots exhibiting both polarities. Region 682 (S13W33) produced
multiple low level flares today, the largest was a C4/Sf which
occurred at 20/0213Z. This region underwent moderate growth today.
A beta-gamma magnetic structure is now evident and the sunspot area
showed a modest increase during the period. Region 688 (S08W48)
showed moderate growth over the period and was numbered today.
IB. Solar Activity Forecast: Solar activity is expected to be at
low to moderate levels. Region 682 and 687 both have a fair
potential for the production of isolated M-class flare activity.
IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z:
The geomagnetic field was at quiet to active levels. Active levels
occurred in response to the sustained southward movement of the Bz
component of the interplanetary magnetic field.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at quiet to unsettled levels throughout the period.
III. Event Probabilities 21 Oct-23 Oct
- Class M 50/50/50
- Class X 01/01/01
- Proton 01/01/01
- PCAF Green
IV. Penticton 10.7 cm Flux
- Observed 20 Oct 111
- Predicted 21 Oct-23 Oct 115/120/125
- 90 Day Mean 20 Oct 105
V. Geomagnetic A Indices
- Observed Afr/Ap 19 Oct 003/004
- Estimated Afr/Ap 20 Oct 006/012
- Predicted Afr/Ap 21 Oct-23 Oct 005/008-005/005-005/005
VI. Geomagnetic Activity Probabilities 21 Oct-23 Oct
A. Middle Latitudes
- Active 15/15/15
- Minor storm 01/01/01
- Major-severe storm 01/01/01
B. High Latitudes
- Active 20/15/15
- Minor storm 05/05/05
- Major-severe storm 01/01/01