Viewing archive of Saturday, 17 May 2025
Solar activity report
Report of Solar-Geophysical Activity 2025 May 17 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 137 Issued at 2200Z on 17 May 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 3 numbered sunspot regions on the disk.
IB. Solar Activity Forecast
Solar activity is expected to be low with
a chance for M-class flares and a slight chance for an X-class flare on
days one, two, and three (18 May, 19 May, 20 May).
IIA. Geophysical Activity Summary 16-2100Z to 17-2100Z
The geomagnetic
field has been at unsettled to major storm levels for the past 24 hours.
Solar wind speed reached a peak of 761 km/s at 17/1957Z. Total IMF
reached 22 nT at 17/0426Z. The maximum southward component of Bz reached
-18 nT at 17/0320Z. Electrons greater than 2 MeV at geosynchronous
orbit reached a peak level of 339 pfu.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected
to be at active to minor storm levels on days one and two (18 May, 19
May) and unsettled to active levels on day three (20 May).
III. Event Probabilities 18 May to 20 May
| Class M | 35% | 35% | 35% |
| Class X | 10% | 10% | 10% |
| Proton | 05% | 05% | 05% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 17 May 117 Predicted 18 May-20 May 118/120/115 90 Day Mean 17 May 161
V. Geomagnetic A Indices
Observed Afr/Ap 16 May 011/013 Estimated Afr/Ap 17 May 032/050 Predicted Afr/Ap 18 May-20 May 021/030-021/032-015/016
VI. Geomagnetic Activity Probabilities 18 May to 20 May
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 40% | 40% | 35% |
| Minor storm | 25% | 30% | 15% |
| Major-severe storm | 05% | 10% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 10% | 10% | 15% |
| Minor storm | 25% | 25% | 30% |
| Major-severe storm | 60% | 65% | 50% |
All times in UTC
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Space weather facts
| Last X-flare | 2025/05/14 | X2.7 |
| Last M-flare | 2025/05/15 | M2.1 |
| Last geomagnetic storm | 2025/05/17 | Kp6+ (G2) |
| Spotless days | |
|---|---|
| Last spotless day | 2022/06/08 |
| Monthly mean Sunspot Number | |
|---|---|
| April 2025 | 140.6 +6.4 |
| May 2025 | 69.8 -70.8 |
| Last 30 days | 94.8 -23.4 |