Joint USAF/NOAA Report of Solar and Geophysical Activity 18 Feb 2003
SDF Number 049 Issued at 2200Z on 18 Feb 2003
IA. Analysis of Solar Active Regions and Activity from 17/2100Z
to 18/2100Z: Solar activity was at very low levels. New Region 289
(N11W52) produced a B9.8 flare at 18/0841 UTC. The most significant
event on the visible disk was a 47 degree disappearing solar
filament that lifted off at 18/0125 UTC and was centered at N34W58.
Associated with the DSF was a CME off the NW limb which does not
appear to have an Earth directed component. Region 288 (N12E32) has
remained relatively stable. Two new regions were numbered today:
Region 289 (N11W52) and Region 290 (N17E46).
IB. Solar Activity Forecast: Solar activity is expected to be very
low to low. Region 288 and 289 have C-class potential.
IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z:
The geomagnetic field has been at quiet to minor storm levels. A
transient passage was observed at the NASA/ACE spacecraft late on 17
February. The transient resulted in an increase in solar wind speed
to over 700 km/s and combined with fluctuating southward Bz was the
source of minor storm conditions measured at the Boulder
magnetometer. At about 18/0400 UTC, the solar wind became very
structured and was marked by a northward turning Bz and a gradual
decline in solar wind speed to current levels near 600 km/s.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at quiet to isolated active levels. Coronal hole
effects are expected to continue after the transient has passed.
III. Event Probabilities 19 Feb-21 Feb
- Class M 05/05/05
- Class X 01/01/01
- Proton 01/01/01
- PCAF green
IV. Penticton 10.7 cm Flux
Observed 18 Feb 110
Predicted 19 Feb-21 Feb 110/110/105
90 Day Mean 18 Feb 146
V. Geomagnetic A Indices
- Observed Afr/Ap 17 Feb 008/011
- Estimated Afr/Ap 18 Feb 018/020
- Predicted Afr/Ap 19 Feb-21 Feb 015/020-015/015-012/015
VI. Geomagnetic Activity Probabilities 19 Feb-21 Feb
A. Middle Latitudes
- Active 30/25/20
- Minor storm 15/10/10
- Major-severe storm 10/05/05
B. High Latitudes
- Active 40/30/25
- Minor storm 30/25/20
- Major-severe storm 15/10/10
