Viewing archive of Sunday, 11 September 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 Sep 11 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 254 Issued at 2200Z on 11 Sep 2011IA. Analysis of Solar Active Regions and Activity from 10-2100Z to 11-2100Z
Solar activity was low. Region 1283 (N14W87) produced
a long duration C6/Sf flare at 11/0851Z. Region 1283 currently is
rotating around the west limb as a Dso spot group with a Beta-Gamma
magnetic classification. Region 1289 (N22E12), a Dko-Beta spot
group with 430 millionths in area, exhibited decay in its smaller
trailing spots. New Region 1292 (N08E66) was numbered today.
IB. Solar Activity Forecast
Solar activity is expected to continue
at low levels with further M-class flares likely on 12 September as
Region 1283 continues to rotate around the west limb. On 12 - 14
September, solar activity is expected to be at low levels with a
slight chance for M-class flares.
IIA. Geophysical Activity Summary 10-2100Z to 11-2100Z
The geomagnetic field was at quiet to minor storm conditions. Minor
storm levels were observed during the period 10/2100 - 2400Z.
Activity was likely due to continued CME effects followed by a
coronal hole high speed stream. At approximately 10/1401Z, a slight
increase in density, wind speed, and temperature was seen in the ACE
solar wind monitor. Solar wind speed continued to increase to
approximately 660 km/s while density dropped to around 1 p/cc during
the period. This was most likely the start of the transition into
the coronal hole high speed stream.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be unsettled to active with minor storm periods possible
on days 1 and 2 (12-13 September) due to continued coronal hole
influence and a possible glancing blow from the 10 September CME.
Conditions are expected to be quiet to unsettled on day 3 (14
September).
III. Event Probabilities 12 Sep to 14 Sep
| Class M | 55% | 35% | 35% |
| Class X | 05% | 01% | 01% |
| Proton | 05% | 01% | 01% |
| PCAF | Green | ||
IV. Penticton 10.7 cm Flux
Observed 11 Sep 121 Predicted 12 Sep-14 Sep 120/115/115 90 Day Mean 11 Sep 100
V. Geomagnetic A Indices
Observed Afr/Ap 10 Sep 020/033 Estimated Afr/Ap 11 Sep 010/018 Predicted Afr/Ap 12 Sep-14 Sep 010/012-010/012-005/008
VI. Geomagnetic Activity Probabilities 12 Sep to 14 Sep
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 20% | 20% | 05% |
| Minor storm | 10% | 10% | 01% |
| Major-severe storm | 05% | 05% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 30% | 30% | 15% |
| Minor storm | 10% | 10% | 05% |
| Major-severe storm | 05% | 05% | 01% |
All times in UTC
Current data suggests there is a slight possibility for aurora to appear at the following high latitude regions in the near future
VorkutaLatest news
Friday, 28 March 2025
X1.1 solar flare
Monday, 24 March 2025
Coronal hole faces Earth
Saturday, 22 March 2025
Strong G3 geomagnetic storm watch for 23 March
Latest forum messages
2025/04/12-13 Filament CMEs 2025/04/16 G2 Watch 29Potential AR4062 4Filaments and prominences 60Incoming & Unnumbered Active Regions 1694AR 4055 96
More topicsSupport SpaceWeatherLive.com!
A lot of people come to SpaceWeatherLive to follow the Sun's activity or if there is aurora to be seen, but with more traffic comes higher server costs. Consider a donation if you enjoy SpaceWeatherLive so we can keep the website online!
Latest alerts
07:09 UTC - Solar flare
Moderate M4.28 flare from sunspot region 4055
06:48 UTC - Radio Blackout
Minor R1 radio blackout in progress (≥M1 - current: M1.53)
06:24 UTC - Solar flare
Moderate M1.49 flare from sunspot region 4055
06:06 UTC - Radio Blackout
Minor R1 radio blackout in progress (≥M1 - current: M1.16)
04:45 UTC - Geomagnetic activity
Active geomagnetic conditions (Kp4) Threshold Reached: 04:29 UTC
Space weather facts
| Last X-flare | 2025/03/28 | X1.1 |
| Last M-flare | 2025/04/14 | M4.2 |
| Last geomagnetic storm | 2025/04/06 | Kp5 (G1) |
| Spotless days | |
|---|---|
| Last spotless day | 2022/06/08 |
| Monthly mean Sunspot Number | |
|---|---|
| March 2025 | 134.2 -20.4 |
| April 2025 | 132.1 -2.1 |
| Last 30 days | 132.4 -10.7 |