Viewing archive of Sunday, 17 August 2025
Solar activity report
Report of Solar-Geophysical Activity 2025 Aug 17 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 229 Issued at 2200Z on 17 Aug 2025IA. Analysis of Solar Active Regions and Activity from 16-2100Z to 17-2100Z Solar activity has been at low levels for the past 24 hours.
There are currently 4 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 (18
Aug, 19 Aug, 20 Aug).
IIA. Geophysical Activity Summary 16-2100Z to 17-2100Z
The geomagnetic
field has been at quiet levels for the past 24 hours. Solar wind speed
reached a peak of 505 km/s at 17/0549Z. Total IMF reached 6 nT at
17/2026Z. The maximum southward component of Bz reached -4 nT at
17/1137Z. Electrons greater than 2 MeV at geosynchronous orbit reached
a peak level of 8022 pfu.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected
to be at quiet to active levels on day one (18 Aug), unsettled to minor
storm levels on day two (19 Aug) and unsettled to active levels on day
three (20 Aug).
III. Event Probabilities 18 Aug to 20 Aug
| Class M | 15% | 15% | 15% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 17 Aug 117 Predicted 18 Aug-20 Aug 115/110/110 90 Day Mean 17 Aug 136
V. Geomagnetic A Indices
Observed Afr/Ap 16 Aug 006/005 Estimated Afr/Ap 17 Aug 005/006 Predicted Afr/Ap 18 Aug-20 Aug 009/012-020/030-014/018
VI. Geomagnetic Activity Probabilities 18 Aug to 20 Aug
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 35% | 45% | 35% |
| Minor storm | 20% | 30% | 15% |
| Major-severe storm | 01% | 05% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 10% | 05% | 10% |
| Minor storm | 25% | 20% | 30% |
| Major-severe storm | 50% | 70% | 50% |
All times in UTC
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Space weather facts
| Last X-flare | 2025/12/01 | X1.9 |
| Last M-flare | 2025/12/04 | M6.0 |
| 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 | 175.4 +83.6 |
| Last 30 days | 107.3 +14.6 |