Viewing archive of Saturday, 17 April 2021
Solar activity report
Report of Solar-Geophysical Activity 2021 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 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 2 numbered sunspot regions on the disk.
IB. Solar Activity Forecast
Solar activity is expected to be very low
with a chance for a C-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 unsettled to minor storm levels for the past 24 hours.
Solar wind speed reached a peak of 612 km/s at 17/0527Z. Total IMF
reached 12 nT at 16/2217Z. The maximum southward component of Bz reached
-10 nT at 16/2158Z. Electrons greater than 2 MeV at geosynchronous
orbit reached a peak level of 1092 pfu.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected
to be at quiet to active levels on days one and two (18 Apr, 19 Apr) and
quiet to unsettled levels on day three (20 Apr).
III. Event Probabilities 18 Apr to 20 Apr
| Class M | 01% | 01% | 01% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 17 Apr 075 Predicted 18 Apr-20 Apr 078/078/075 90 Day Mean 17 Apr 076
V. Geomagnetic A Indices
Observed Afr/Ap 16 Apr 015/019 Estimated Afr/Ap 17 Apr 020/030 Predicted Afr/Ap 18 Apr-20 Apr 012/016-010/012-009/008
VI. Geomagnetic Activity Probabilities 18 Apr to 20 Apr
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 35% | 35% | 20% |
| Minor storm | 15% | 15% | 05% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 10% | 10% | 20% |
| Minor storm | 25% | 25% | 25% |
| Major-severe storm | 50% | 50% | 25% |
All times in UTC
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