Viewing archive of Saturday, 1 October 2011
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 2011 Oct 01 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 274 Issued at 2200Z on 01 Oct 2011IA. Analysis of Solar Active Regions and Activity from 30-2100Z to 01-2100Z Solar activity has been moderate. Region 1305 (N12W12)
produced an M1/1n flare at 01/0959Z associated with an
Earth-directed CME. The CME became visible in STEREO imagery at
01/1109Z and has an estimated speed of 500 km/s. Region 1302
(N16W41) produced a Sf optical flare immediately before the M1 flare
at 01/0917Z. The two events were associated with a pair of Type II
Sweeps (620 km/s at 01/0906Z and 850 km/s at 01/0955Z), a Type IV
Sweep and a 180 sfu Tenflare. Region 1305 has grown slightly in area
and spot number and has a beta-gamma magnetic configuration. Region
1302 maintains an area of 700 millionths and a beta-gamma-delta
magnetic configuration.
IB. Solar Activity Forecast
Solar activity is expected to be low
to moderate with a slight chance for an X-class event from Regions
1302 and 1305 for the next three days (02-04 October).
IIA. Geophysical Activity Summary 30-2100Z to 01-2100Z
The geomagnetic field was quiet to unsettled with isolated active
periods from 01/0000-0600Z as measured by the Boulder magnetometer.
The activity was a result of multiple solar sector boundary
crossings. The greater than 2 MeV electron flux at geosynchronous
orbit reached high levels during the period.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be quiet to unsettled on day one (02 October) due to
effects from the coronal hole high speed stream and possible effects
from the CME observed on 29 September. Mostly quiet conditions are
expected on day two (03 October). Quiet to unsettled conditions with
a chance for active and isolated minor storm periods are expected on
day three (04 October) due to a combination of the CMEs observed on
30 September and 01 October. The two CMEs are due to arrive early
and late on day three, respectively.
III. Event Probabilities 02 Oct to 04 Oct
| Class M | 70% | 70% | 70% |
| Class X | 20% | 20% | 20% |
| Proton | 15% | 15% | 15% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 01 Oct 137 Predicted 02 Oct-04 Oct 140/140/140 90 Day Mean 01 Oct 111
V. Geomagnetic A Indices
Observed Afr/Ap 30 Sep 005/008 Estimated Afr/Ap 01 Oct 012/012 Predicted Afr/Ap 02 Oct-04 Oct 008/008-005/005-015/015
VI. Geomagnetic Activity Probabilities 02 Oct to 04 Oct
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 20% | 10% | 45% |
| Minor storm | 10% | 01% | 25% |
| Major-severe storm | 01% | 01% | 05% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 20% | 15% | 45% |
| Minor storm | 10% | 01% | 25% |
| Major-severe storm | 01% | 01% | 10% |
All times in UTC
Latest news
Sunday, 7 December 2025
M8.1 solar flare with earth-directed CME
Monday, 1 December 2025
X1.9 solar flare, Coronal hole faces Earth
Friday, 14 November 2025
X4.0 solar flare
Latest forum messages
AR4294 / 4296 / 4298 394AR4299 M8.1 CME 2025/12/06 88AR 4299 116New paper on the Gannon Storm 10-11 May 2024 2Electron event 10
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!
Space weather facts
| Last X-flare | 2025/12/08 | X1.1 |
| Last M-flare | 2025/12/08 | M1.8 |
| Last geomagnetic storm | 2025/12/04 | Kp5 (G1) |
| Spotless days | |
|---|---|
| Last spotless day | 2022/06/08 |
| Monthly mean Sunspot Number | |
|---|---|
| November 2025 | 91.8 -22.8 |
| December 2025 | 162.7 +70.9 |
| Last 30 days | 108 +13.3 |