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Solar activity report
Report of Solar-Geophysical Activity 2025 May 28 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 148 Issued at 2200Z on 28 May 2025IA. Analysis of Solar Active Regions and Activity from 27-2100Z to 28-2100Z Solar activity has been at low levels for the past 24 hours.
There are currently 8 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 (29 May, 30 May, 31 May).
IIA. Geophysical Activity Summary 27-2100Z to 28-2100Z
The geomagnetic
field has been at quiet to active levels for the past 24 hours. Solar
wind speed reached a peak of 648 km/s at 28/0246Z. Total IMF reached 18
nT at 28/2040Z. The maximum southward component of Bz reached -9 nT at
27/2102Z. Electrons greater than 2 MeV at geosynchronous orbit reached
a peak level of 416 pfu.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected
to be at quiet to minor storm levels on days one and two (29 May, 30
May) and quiet to active levels on day three (31 May). Protons have a
slight chance of crossing threshold on days one, two, and three (29 May,
30 May, 31 May).
III. Event Probabilities 29 May to 31 May
| Class M | 50% | 50% | 50% |
| Class X | 10% | 10% | 10% |
| Proton | 10% | 10% | 10% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 28 May 144 Predicted 29 May-31 May 140/138/135 90 Day Mean 28 May 154
V. Geomagnetic A Indices
Observed Afr/Ap 27 May 012/ 015 Estimated Afr/Ap 28 May 019/021 Predicted Afr/Ap 29 May-31 May 017/020-014/018-008/012
VI. Geomagnetic Activity Probabilities 29 May to 31 May
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 40% | 40% | 30% |
| Minor storm | 25% | 25% | 10% |
| Major-severe storm | 05% | 05% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 10% | 10% | 15% |
| Minor storm | 25% | 25% | 30% |
| Major-severe storm | 60% | 60% | 40% |
All times in UTC
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Space weather facts
| Last X-flare | 2025/12/08 | X1.1 |
| Last M-flare | 2025/12/08 | M1.8 |
| 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 | 162.7 +70.9 |
| Last 30 days | 108 +13.3 |