Viewing archive of Friday, 28 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 28 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 271 Issued at 2200Z on 28 Sep 2001IA. Analysis of Solar Active Regions and Activity from 27-2100Z to 28-2100Z Solar activity has been moderate. There were three
M-class events observed during the past 24 hours. The first of these
was an M3/2n from Region 9636 (N14E13) at 0830 UTC, which was
associated with type II and type IV sweeps and a partial halo CME
that appeared to be centered over the east limb. The second was an
M2/1n from Region 9628 (S18W48) at 1014 UTC which was associated
with a CME that was centered over the southwest limb. The 3rd was an
M1/1f from Region 9637 (S15E18) at 1926 UTC. Regions 9628 and 9632
(S18W33) continue to dominate the disk in sunspot area and still
maintain magnetic delta configurations. 9628 is showing some growth
in the northern portion of the region. Region 9632 has been
remarkably quiet, but continues to show a strong delta along an
East-West inversion line. Region 9636 seems to be decaying slightly,
but has a fairly complicated magnetic structure (gamma magnetic
class).
IB. Solar Activity Forecast
Solar activity is expected to be
moderate to high. Regions 9636, 9637, 9632 and 9628 all are capable
of producing additional M-class level activity. Regions 9628 and
9632 have a fair chance for producing an isolated major flare event
sometime during the next three days.
IIA. Geophysical Activity Summary 27-2100Z to 28-2100Z
The geomagnetic field was quiet to unsettled during the past 24
hours. The greater than 10 MeV proton event that began at 24/1215
UTC continues in progress as the flux levels declined slowly. The
flux level at forecast issue time was 94 pfu. The greater than 2 MeV
electrons attained high levels during the past 24 hours.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be unsettled to slightly active during the next 48
hours. The influence of a favorably positioned coronal hole is
expected to increase activity levels slightly. In addition, there is
a possibility for some active conditions on the third day as the
result of a glancing blow from either of today's CME events. The
greater than 10 MeV proton event is expected to end sometime in the
next 24-36 hours.
III. Event Probabilities 29 Sep to 01 Oct
| Class M | 80% | 80% | 80% |
| Class X | 30% | 30% | 30% |
| Proton | 99% | 30% | 30% |
| PCAF | in progress | ||
IV. Penticton 10.7 cm Flux
Observed 28 Sep 266 Predicted 29 Sep-01 Oct 260/260/255 90 Day Mean 28 Sep 174
V. Geomagnetic A Indices
Observed Afr/Ap 27 Sep 009/010 Estimated Afr/Ap 28 Sep 013/015 Predicted Afr/Ap 29 Sep-01 Oct 015/015-015/018-020/018
VI. Geomagnetic Activity Probabilities 29 Sep to 01 Oct
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 25% | 25% | 20% |
| Minor storm | 20% | 20% | 30% |
| Major-severe storm | 20% | 20% | 25% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 30% | 30% | 25% |
| Minor storm | 25% | 25% | 35% |
| Major-severe storm | 20% | 20% | 30% |
All times in UTC
Latest news
Monday, 30 March 2026
X1.5 solar flare
Tuesday, 17 March 2026
M2.7 solar flare, CME arrival possible
Sunday, 1 February 2026
Complex sunspot region 4366
Latest forum messages
Coronal Holes 42/44 10AR4419 35Space Weather Watch App 16Current Farside Activity 456Filaments and prominences 545
More topicsSupport SpaceWeatherLive.com!
A lot of people come to SpaceWeatherLive to follow the Solar activity or if there is a chance to see the aurora, but with more traffic comes higher costs to keep the servers online. If you like SpaceWeatherLive and want to support the project you can choose a subscription for an ad-free site or consider a donation. With your help we can keep SpaceWeatherLive online!
