Viewing archive of Thursday, 18 September 2025
Solar activity report
Report of Solar-Geophysical Activity 2025 Sep 18 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 261 Issued at 2200Z on 18 Sep 2025IA. Analysis of Solar Active Regions and Activity from 17-2100Z to 18-2100Z Solar activity has been at low levels for the past 24 hours.
There are currently 7 numbered sunspot regions on the disk.
IB. Solar Activity Forecast
Solar activity is expected to be low with
a chance for M-class flares on days one, two, and three (19 Sep, 20 Sep,
21 Sep).
IIA. Geophysical Activity Summary 17-2100Z to 18-2100Z
The geomagnetic
field has been at quiet to unsettled levels for the past 24 hours. Solar
wind speed reached a peak of 614 km/s at 18/0328Z. Electrons greater
than 2 MeV at geosynchronous orbit reached a peak level of 6213 pfu.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected
to be at quiet levels on days one and two (19 Sep, 20 Sep) and quiet to
active levels on day three (21 Sep).
III. Event Probabilities 19 Sep to 21 Sep
| Class M | 35% | 35% | 35% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 18 Sep 150 Predicted 19 Sep-21 Sep 150/150/150 90 Day Mean 18 Sep 144
V. Geomagnetic A Indices
Observed Afr/Ap 17 Sep 010/012 Estimated Afr/Ap 18 Sep 007/007 Predicted Afr/Ap 19 Sep-21 Sep 006/005-006/005-012/015
VI. Geomagnetic Activity Probabilities 19 Sep to 21 Sep
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 10% | 10% | 30% |
| Minor storm | 01% | 01% | 10% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 15% | 15% | 15% |
| Minor storm | 20% | 20% | 30% |
| Major-severe storm | 20% | 20% | 40% |
All times in UTC
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