Viewing archive of Tuesday, 18 April 2023
Solar activity report
Report of Solar-Geophysical Activity 2023 Apr 18 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 108 Issued at 2200Z on 18 Apr 2023IA. 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.
The largest solar event of the period was a C4 event observed at
18/1529Z from Region 3280 (S08W94). 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 (19 Apr, 20 Apr, 21 Apr).
IIA. Geophysical Activity Summary 17-2100Z to 18-2100Z
The geomagnetic
field has been at quiet to active levels for the past 24 hours. Solar
wind speed reached a peak of 624 km/s at 18/2033Z. Total IMF reached 19
nT at 18/1612Z. The maximum southward component of Bz reached -16 nT at
18/1549Z. Electrons greater than 2 MeV at geosynchronous orbit reached
a peak level of 198 pfu.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected
to be at quiet to minor storm levels on day one (19 Apr), unsettled to
minor storm levels on day two (20 Apr) and quiet to active levels on day
three (21 Apr).
III. Event Probabilities 19 Apr to 21 Apr
| Class M | 40% | 40% | 40% |
| Class X | 10% | 10% | 10% |
| Proton | 05% | 05% | 05% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 18 Apr 153 Predicted 19 Apr-21 Apr 150/145/140 90 Day Mean 18 Apr 162
V. Geomagnetic A Indices
Observed Afr/Ap 17 Apr 006/005 Estimated Afr/Ap 18 Apr 012/018 Predicted Afr/Ap 19 Apr-21 Apr 018/020-017/024-015/016
VI. Geomagnetic Activity Probabilities 19 Apr to 21 Apr
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 40% | 40% | 25% |
| Minor storm | 20% | 20% | 10% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 10% | 10% | 15% |
| Minor storm | 25% | 25% | 25% |
| Major-severe storm | 60% | 60% | 35% |
All times in UTC
Latest news
Friday, 28 March 2025
X1.1 solar flare
Monday, 24 March 2025
Coronal hole faces Earth
Saturday, 22 March 2025
Strong G3 geomagnetic storm watch for 23 March
Latest forum messages
Incoming & Unnumbered Active Regions 1673AR 4054 21AR4048 124Unspecified geomagnetic activity 2229Aurora photography hints for those of us with smartphones 66
More topicsSupport SpaceWeatherLive.com!
A lot of people come to SpaceWeatherLive to follow the Sun's activity or if there is aurora to be seen, but with more traffic comes higher server costs. Consider a donation if you enjoy SpaceWeatherLive so we can keep the website online!
Latest alerts
06:30 UTC - Type II Radio Emission
Begin Time: 08/04/2025 05:53 UTC Estimated Velocity: 456km/sec.
05:15 UTC - Hemispheric Power Index
The OVATION model predicts the Hemispheric Power Index to reach 50GW at 06:02 UTC
00:55 UTC - Coronal hole
A southern hemisphere coronal hole is facing Earth. Enhanced solar wind could arrive in ~3 days
Monday, 7 April 2025
20:45 UTC - Geomagnetic activity
Active geomagnetic conditions (Kp4) Threshold Reached: 20:39 UTC
17:33 UTC - Hemispheric Power Index
The OVATION model predicts the Hemispheric Power Index to reach 51GW at 18:18 UTC
Space weather facts
| Last X-flare | 2025/03/28 | X1.1 |
| Last M-flare | 2025/04/05 | M1.0 |
| Last geomagnetic storm | 2025/04/06 | Kp5 (G1) |
| Spotless days | |
|---|---|
| Last spotless day | 2022/06/08 |
| Monthly mean Sunspot Number | |
|---|---|
| March 2025 | 134.2 -20.4 |
| April 2025 | 151.3 +17.1 |
| Last 30 days | 135.2 -4.5 |