Joint USAF/NOAA Report of Solar and Geophysical Activity 21 Dec 2002
SDF Number 355 Issued at 2200Z on 21 Dec 2002
IA. Analysis of Solar Active Regions and Activity from 20/2100Z
to 21/2100Z: Solar activity was at low levels. Region 226 (S28W54)
produced most of today’s observed activity, a C4.6/1f occurring at
21/0453 UTC was the largest flare during the period. The
beta-gamma-delta magnetic structure remains intact although much
decay was noted in spot groups areal coverage today. Region 229
(N19W29) continues to show steady decay and was fairly quiescent
today. Region 230 (S08E06) underwent little change but remains a
beta-gamma magnetic complex. Region 232 (N13W08) was newly assigned
today.
IB. Solar Activity Forecast: Solar activity is expected to be at
low to moderate levels. Regions 226 and 230 are capable of
producing M-class flare activity.
IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z:
The geomagnetic field was predominantly at quiet to active levels as
the geoeffective coronal hole high speed stream wanes. Middle and
high latitudes experienced storming conditions between 21/0300 and
0600 UTC.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at active to minor storm levels for day one of the
forecast period. The CME from the M2.7 flare late on 19 December is
expected to arrive early to mid-day on 22 December. Predominantly
quiet to unsettled conditions are expected on days two and three.
III. Event Probabilities 22 Dec-24 Dec
- Class M 50/50/50
- Class X 10/10/10
- Proton 05/05/05
- PCAF yellow
IV. Penticton 10.7 cm Flux
- Observed 21 Dec 184
- Predicted 22 Dec-24 Dec 185/180/180
- 90 Day Mean 21 Dec 167
V. Geomagnetic A Indices
- Observed Afr/Ap 20 Dec 012/016
- Estimated Afr/Ap 21 Dec 015/018
- Predicted Afr/Ap 22 Dec-24 Dec 025/025-012/015-006/010
VI. Geomagnetic Activity Probabilities 22 Dec-24 Dec
A. Middle Latitudes
- Active 35/20/15
- Minor storm 25/10/01
- Major-severe storm 10/05/01
B. High Latitudes
- Active 40/30/20
- Minor storm 30/15/05
- Major-severe storm 15/10/01
