Joint USAF/NOAA Report of Solar and Geophysical Activity 19 Sep 2002
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 262 Issued at 2200Z on 19 Sep 2002
IA. Analysis of Solar Active Regions and Activity from 18/2100Z
to 19/2100Z: Solar activity was low. The largest event of the period
was a C4/1f flare from Region 125 (S08E55). An associated Type II
radio sweep and CME was observed with this flare, but the ejecta was
not earthward directed. Region 119 (S14W10) produced occasional low
C-class flares. This region continues to develop and a weak delta
configuration is now evident. Region 105 (S08W83) also produced
minor C-class flares as it rotates around the west limb. New Region
126 (S23E75) was numbered today.
IB. Solar Activity Forecast: Solar activity is expected to be low
to moderate. Developing Region 119 has best potential for a low
M-class flare. There is still a small chance for a low M-class flare
from Region 105 on the west limb.
IIA. Geophysical Activity Summary 18/2100Z to 19/2100Z:
The geomagnetic field ranged from quiet to minor storm levels. A weak
shock was observed at the ACE spacecraft just before 19/0600Z. Solar
wind speed gradually increased to over 750 km/s by late in the
period, but total magnetic field measurements and densities remained
very low. This disturbance is likely associated with the C8 flare
and CME observed on 17 September. The greater than 2 MeV electron
flux was at moderate to high levels.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to continue at unsettled to minor storm levels through day
one. Unsettled conditions are expected to prevail after the current
disturbance subsides.
III. Event Probabilities 20 Sep-22 Sep
Class M 40/40/40
Class X 05/05/05
Proton 05/05/05
PCAF green
IV. Penticton 10.7 cm Flux
Observed 19 Sep 165
Predicted 20 Sep-22 Sep 165/160/155
90 Day Mean 19 Sep 178
V. Geomagnetic A Indices
Observed Afr/Ap 18 Sep 013/014
Estimated Afr/Ap 19 Sep 018/018
Predicted Afr/Ap 20 Sep-22 Sep 020/020-008/010-008/010
VI. Geomagnetic Activity Probabilities 20 Sep-22 Sep
A. Middle Latitudes
Active 50/30/20
Minor storm 30/10/05
Major-severe storm 15/05/01
B. High Latitudes
Active 40/40/25
Minor storm 40/15/05
Major-severe storm 20/10/01