Viewing archive of Tuesday, 18 September 2001
Solar activity report
Any mentioned solar flare in this report has a scaling factor applied by the Space Weather Prediction Center (SWPC). Because of the SWPC scaling factor, solar flares are reported as 42% smaller than for the science quality data. The scaling factor has been removed from our archived solar flare data to reflect the true physical units.
Report of Solar-Geophysical Activity 2001 Sep 18 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 261 Issued at 2200Z on 18 Sep 2001IA. Analysis of Solar Active Regions and Activity from 17-2100Z to 18-2100Z Solar activity remained at high levels due to the
number of M-class flares. Six M1-level flares were observed over the
past 24 hours, occurring in Regions 9608 (S30W84), 9616 (S13W11),
9620 (N12E44), and new Region 9628 (S17E79). Region 9608 has rotated
out of view beyond the west limb. The largest sunspot groups
currently on the disk are 9616 and 9628. New Regions 9625 (S30W12),
9626 (N25E47), and 9627 (N05E73) were also numbered.
IB. Solar Activity Forecast
Solar activity is expected to be
moderate to high. Additional M-class flares are possible in Regions
9616, 9620, and 9628. Another major flare in Region 9608 from beyond
the west limb is not out of the question.
IIA. Geophysical Activity Summary 17-2100Z to 18-2100Z
The geomagnetic field ranged from quiet to active. Solar wind
information from the NASA ACE spacecraft exhibited increased
variability including higher IMF field intensity and southward Bz.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be quiet to unsettled with occasional active periods.
Increased activity is possible from a number of CME events and a
possible high-speed coronal hole stream.
III. Event Probabilities 19 Sep to 21 Sep
| Class M | 80% | 80% | 80% |
| Class X | 10% | 05% | 05% |
| Proton | 10% | 01% | 01% |
| PCAF | yellow | ||
IV. Penticton 10.7 cm Flux
Observed 18 Sep 204 Predicted 19 Sep-21 Sep 205/200/195 90 Day Mean 18 Sep 165
V. Geomagnetic A Indices
Observed Afr/Ap 17 Sep 006/010 Estimated Afr/Ap 18 Sep 008/010 Predicted Afr/Ap 19 Sep-21 Sep 015/020-012/015-010/010
VI. Geomagnetic Activity Probabilities 19 Sep to 21 Sep
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 20% | 15% | 10% |
| Minor storm | 10% | 10% | 05% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 25% | 20% | 15% |
| Minor storm | 15% | 15% | 10% |
| Major-severe storm | 05% | 01% | 01% |
All times in UTC
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