Viewing archive of Friday, 17 April 2026
Solar activity report
Report of Solar-Geophysical Activity 2026 Apr 17 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 107 Issued at 2200Z on 17 Apr 2026IA. 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 on days one, two, and three (18 Apr, 19 Apr,
20 Apr).
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 365 km/s at 17/0316Z. Total IMF reached 11 nT at
17/1729Z. The maximum southward component of Bz reached -3 nT at
17/1744Z. Electrons greater than 2 MeV at geosynchronous orbit reached
a peak level of 2441 pfu.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected
to be at unsettled to major storm levels on day one (18 Apr), unsettled
to minor storm levels on day two (19 Apr) and quiet to active levels on
day three (20 Apr).
III. Event Probabilities 18 Apr to 20 Apr
| Class M | 25% | 25% | 25% |
| Class X | 05% | 05% | 05% |
| Proton | 01% | 01% | 01% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 17 Apr 107 Predicted 18 Apr-20 Apr 105/105/105 90 Day Mean 17 Apr 133
V. Geomagnetic A Indices
Observed Afr/Ap 16 Apr 003/003 Estimated Afr/Ap 17 Apr 015/020 Predicted Afr/Ap 18 Apr-20 Apr 025/040-020/025-014/018
VI. Geomagnetic Activity Probabilities 18 Apr to 20 Apr
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 30% | 35% | 35% |
| Minor storm | 40% | 35% | 10% |
| Major-severe storm | 25% | 10% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 05% | 05% | 15% |
| Minor storm | 15% | 20% | 30% |
| Major-severe storm | 85% | 70% | 45% |
All times in UTC
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Space weather facts
| Last X-flare | 2026/07/04 | X1.3 |
| Last M-flare | 2026/07/12 | M1.19 |
| Last geomagnetic storm | 2026/07/04 | Kp7+ (G3) |
| Spotless days | |
|---|---|
| Last 365 days | 3 days |
| 2026 | 3 days (2%) |
| Last spotless day | 2026/02/24 |
| Monthly mean Sunspot Number | |
|---|---|
| June 2026 | 94.4 -7.1 |
| July 2026 | 74.8 -19.6 |
| Last 30 days | 87 -20.2 |
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