Viewing archive of Saturday, 11 September 2021
Solar activity report
Report of Solar-Geophysical Activity 2021 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 2021IA. Analysis of Solar Active Regions and Activity from 10-2100Z to 11-2100Z Solar activity has been at low levels for the past 24 hours.
The largest solar event of the period was a C1 event observed at
11/0519Z from Region 2868 (S19W49). There are currently 5 numbered
sunspot regions on the disk.
IB. Solar Activity Forecast
Solar activity is expected to be low with
a slight chance for an M-class flare on days one, two, and three (12
Sep, 13 Sep, 14 Sep).
IIA. Geophysical Activity Summary 10-2100Z to 11-2100Z
The geomagnetic
field has been at quiet to active levels for the past 24 hours. Solar
wind speed reached a peak of 381 km/s at 11/0315Z. Total IMF reached 13
nT at 11/0438Z. The maximum southward component of Bz reached -10 nT at
10/2244Z. Electrons greater than 2 MeV at geosynchronous orbit reached
a peak level of 150 pfu.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected
to be at quiet to unsettled levels on day one (12 Sep) and quiet levels
on days two and three (13 Sep, 14 Sep).
III. Event Probabilities 12 Sep to 14 Sep
| Class M | 20% | 20% | 20% |
| Class X | 05% | 05% | 05% |
| Proton | 01% | 01% | 01% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 11 Sep 092 Predicted 12 Sep-14 Sep 092/090/086 90 Day Mean 11 Sep 081
V. Geomagnetic A Indices
Observed Afr/Ap 10 Sep 009/007 Estimated Afr/Ap 11 Sep 006/007 Predicted Afr/Ap 12 Sep-14 Sep 008/008-006/005-006/005
VI. Geomagnetic Activity Probabilities 12 Sep to 14 Sep
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 15% | 10% | 10% |
| Minor storm | 05% | 01% | 01% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 15% | 15% | 15% |
| Minor storm | 25% | 20% | 20% |
| Major-severe storm | 25% | 20% | 20% |
All times in UTC
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| Last M-flare | 2026/03/28 | M1.3 |
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| Spotless days | |
|---|---|
| Last 365 days | 3 days |
| 2026 | 3 days (3%) |
| Last spotless day | 2026/02/24 |
| Monthly mean Sunspot Number | |
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