Viewing archive of Sunday, 28 September 2025
Solar activity report
Report of Solar-Geophysical Activity 2025 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 2025IA. Analysis of Solar Active Regions and Activity from 27-2100Z to 28-2100Z Solar activity has been at high levels for the past 24 hours.
There are currently 9 numbered sunspot regions on the disk.
IB. Solar Activity Forecast
Solar activity is likely to be moderate
with a slight chance for an X-class flare on days one, two, and three
(29 Sep, 30 Sep, 01 Oct).
IIA. Geophysical Activity Summary 27-2100Z to 28-2100Z
The geomagnetic
field has been at quiet to unsettled levels for the past 24 hours. Solar
wind speed reached a peak of 447 km/s at 28/1512Z. Total IMF reached 13
nT at 28/1843Z. The maximum southward component of Bz reached -6 nT at
28/0022Z. Electrons greater than 2 MeV at geosynchronous orbit reached
a peak level of 445 pfu.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected
to be at quiet to active levels on day one (29 Sep), quiet to unsettled
levels on day two (30 Sep) and quiet levels on day three (01 Oct).
III. Event Probabilities 29 Sep to 01 Oct
| Class M | 55% | 55% | 55% |
| Class X | 10% | 10% | 10% |
| Proton | 01% | 01% | 01% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 28 Sep 171 Predicted 29 Sep-01 Oct 175/180/180 90 Day Mean 28 Sep 149
V. Geomagnetic A Indices
Observed Afr/Ap 27 Sep 005/006 Estimated Afr/Ap 28 Sep 010/012 Predicted Afr/Ap 29 Sep-01 Oct 013/014-008/008-006/005
VI. Geomagnetic Activity Probabilities 29 Sep to 01 Oct
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 30% | 25% | 10% |
| Minor storm | 10% | 10% | 01% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 15% | 15% | 15% |
| Minor storm | 30% | 30% | 20% |
| Major-severe storm | 40% | 35% | 20% |
All times in UTC
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Space weather facts
| Last X-flare | 2026/01/18 | X1.9 |
| Last M-flare | 2026/01/21 | M3.4 |
| Last geomagnetic storm | 2026/01/20 | Kp8 (G4) |
| Spotless days | |
|---|---|
| Last spotless day | 2022/06/08 |
| Monthly mean Sunspot Number | |
|---|---|
| December 2025 | 124 +32.2 |
| January 2026 | 107.3 -16.8 |
| Last 30 days | 111.9 +4 |