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Solar activity report
Report of Solar-Geophysical Activity 2021 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 2021IA. Analysis of Solar Active Regions and Activity from 17-2100Z to 18-2100Z 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 (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 668 km/s at 17/2136Z. Total IMF reached 6
nT at 18/0050Z. The maximum southward component of Bz reached -5 nT at
18/0337Z. Electrons greater than 2 MeV at geosynchronous orbit reached
a peak level of 14078 pfu.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected
to be at quiet to active levels on day one (19 Apr), quiet to unsettled
levels on day two (20 Apr) and quiet levels on day three (21 Apr).
III. Event Probabilities 19 Apr to 21 Apr
| Class M | 01% | 01% | 01% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 18 Apr 078 Predicted 19 Apr-21 Apr 078/075/075 90 Day Mean 18 Apr 076
V. Geomagnetic A Indices
Observed Afr/Ap 17 Apr 020/024 Estimated Afr/Ap 18 Apr 011/014 Predicted Afr/Ap 19 Apr-21 Apr 012/012-009/008-006/005
VI. Geomagnetic Activity Probabilities 19 Apr to 21 Apr
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 40% | 25% | 15% |
| Minor storm | 15% | 10% | 01% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 10% | 15% | 15% |
| Minor storm | 25% | 30% | 20% |
| Major-severe storm | 50% | 40% | 20% |
All times in UTC
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