Joint USAF/NOAA Report of Solar and Geophysical Activity 26 Feb 2003
SDF Number 057 Issued at 2200Z on 26 Feb 2003
IA. Analysis of Solar Active Regions and Activity from 25/2100Z
to 26/2100Z: Solar activity was very low. Today’s largest flare was
a B7/Sf at 0946 UTC from Region 290 (N18W60). A few additional
B-class flares were observed, including one from the new active
region on the east limb at S18.
IB. Solar Activity Forecast: Solar activity is expected to be very
low to low.
IIA. Geophysical Activity Summary 25/2100Z to 26/2100Z:
The geomagnetic field was at quiet to active levels. An interval of
weakly to moderately negative interplanetary Bz magnetic field (-5
to -10 nT) was observed from 0300-0600 UTC and led to active levels
from 0600-1200 UTC. Solar wind data also showed a density
enhancement and magnetic field enhancement beginning at 1800 UTC,
accompanied by a discontinuous shift in the spiral angle from an
away sector to a towards sector, suggesting a likely solar sector
boundary crossing.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be predominantly unsettled for the next three days, with
a slight chance for some isolated active periods. The somewhat
enhanced levels of activity are expected because of favorably
positioned solar coronal holes.
III. Event Probabilities 27 Feb-01 Mar
- Class M 05/05/05
- Class X 01/01/01
- Proton 01/01/01
- PCAF green
IV. Penticton 10.7 cm Flux
- Observed 26 Feb 109
- Predicted 27 Feb-01 Mar 115/120/120
- 90 Day Mean 26 Feb 143
V. Geomagnetic A Indices
- Observed Afr/Ap 25 Feb 002/005
- Estimated Afr/Ap 26 Feb 011/015
- Predicted Afr/Ap 27 Feb-01 Mar 012/012-012/012-012/012
VI. Geomagnetic Activity Probabilities 27 Feb-01 Mar
A. Middle Latitudes
- Active 35/35/35
- Minor storm 20/20/20
- Major-severe storm 05/05/05
B. High Latitudes
- Active 40/40/40
- Minor storm 25/25/25
- Major-severe storm 05/05/05
