Viewing archive of Tuesday, 17 August 2021
Solar activity report
Report of Solar-Geophysical Activity 2021 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 2021IA. Analysis of Solar Active Regions and Activity from 16-2100Z to 17-2100Z Solar activity has been at very low levels for the past 24
hours. There are currently 1 numbered sunspot regions on the disk.
IB. Solar Activity Forecast
Solar activity is expected to be very low
with a slight chance for a C-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 to unsettled levels for the past 24 hours. Solar
wind speed reached a peak of 492 km/s at 16/2317Z. Electrons greater
than 2 MeV at geosynchronous orbit reached a peak level of 618 pfu.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected
to be at quiet levels on days one, two, and three (18 Aug, 19 Aug, 20
Aug).
III. Event Probabilities 18 Aug to 20 Aug
| Class M | 01% | 01% | 01% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 17 Aug 073 Predicted 18 Aug-20 Aug 073/073/073 90 Day Mean 17 Aug 079
V. Geomagnetic A Indices
Observed Afr/Ap 16 Aug 008/007 Estimated Afr/Ap 17 Aug 005/005 Predicted Afr/Ap 18 Aug-20 Aug 005/005-005/005-005/005
VI. Geomagnetic Activity Probabilities 18 Aug to 20 Aug
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 10% | 10% | 10% |
| Minor storm | 01% | 01% | 01% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 15% | 15% | 15% |
| Minor storm | 20% | 20% | 20% |
| Major-severe storm | 15% | 15% | 15% |
All times in UTC
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| Last X-flare | 2026/03/30 | X1.5 |
| Last M-flare | 2026/04/09 | M1.0 |
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