Viewing archive of Friday, 21 April 2017
Solar activity report
Any mentioned solar flare in this report has a scaling factor applied by the Space Weather Prediction Center (SWPC). Because of the SWPC scaling factor, solar flares are reported as 42% smaller than for the science quality data. The scaling factor has been removed from our archived solar flare data to reflect the true physical units.
Report of Solar-Geophysical Activity 2017 Apr 21 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 111 Issued at 2200Z on 21 Apr 2017IA. Analysis of Solar Active Regions and Activity from 20-2100Z to 21-2100Z Solar activity has been at very 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 very low
with a chance for a C-class flares on days one, two, and three (22 Apr,
23 Apr, 24 Apr).
IIA. Geophysical Activity Summary 20-2100Z to 21-2100Z
The geomagnetic
field has been at quiet to minor storm levels for the past 24 hours.
Solar wind speed reached a peak of 691 km/s at 21/2050Z. Total IMF
reached 14 nT at 21/1613Z. The maximum southward component of Bz reached
-12 nT at 21/1635Z. Electrons greater than 2 MeV at geosynchronous orbit
reached a peak level of 2805 pfu.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected
to be at quiet to unsettled levels on day one (22 Apr), active to major
storm levels on day two (23 Apr) and active to minor storm levels on day
three (24 Apr).
III. Event Probabilities 22 Apr to 24 Apr
| Class M | 05% | 05% | 05% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 21 Apr 082 Predicted 22 Apr-24 Apr 082/082/082 90 Day Mean 21 Apr 078
V. Geomagnetic A Indices
Observed Afr/Ap 20 Apr 020/030 Estimated Afr/Ap 21 Apr 012/018 Predicted Afr/Ap 22 Apr-24 Apr 013/015-028/040-023/030
VI. Geomagnetic Activity Probabilities 22 Apr to 24 Apr
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 40% | 30% | 40% |
| Minor storm | 25% | 40% | 30% |
| Major-severe storm | 05% | 15% | 05% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 10% | 05% | 05% |
| Minor storm | 25% | 20% | 20% |
| Major-severe storm | 60% | 75% | 65% |
All times in UTC
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