Viewing archive of Sunday, 21 April 2013
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 2013 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 2013IA. Analysis of Solar Active Regions and Activity from 20-2100Z to 21-2100Z 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
21/1839Z from Region 1726 (N12W22). There are currently 3 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 and two (22 Apr, 23 Apr) and expected to be low with a chance
for M-class flares on day three (24 Apr).
IIA. Geophysical Activity Summary 20-2100Z to 21-2100Z
The geomagnetic
field has been at quiet levels for the past 24 hours. Solar wind speed,
as measured by the ACE spacecraft, reached a peak speed of 412 km/s at
21/0728Z. Total IMF reached 7 nT at 21/1656Z. The maximum southward
component of Bz reached -1 nT at 21/0145Z. Protons greater than 10 MeV
at geosynchronous orbit reached a peak level of 3 pfu at 21/1640Z.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected
to be at quiet to unsettled levels on day one (22 Apr) and quiet to
active levels on days two and three (23 Apr, 24 Apr). Protons greater
than 10 Mev have a slight chance of crossing threshold on days one and
two (22 Apr, 23 Apr).
III. Event Probabilities 22 Apr to 24 Apr
| Class M | 40% | 40% | 40% |
| Class X | 15% | 15% | 05% |
| Proton | 15% | 15% | 01% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 21 Apr 109 Predicted 22 Apr-24 Apr 115/115/115 90 Day Mean 21 Apr 111
V. Geomagnetic A Indices
Observed Afr/Ap 20 Apr 002/004 Estimated Afr/Ap 21 Apr 002/003 Predicted Afr/Ap 22 Apr-24 Apr 006/008-008/012-011/012
VI. Geomagnetic Activity Probabilities 22 Apr to 24 Apr
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 15% | 25% | 25% |
| Minor storm | 05% | 05% | 05% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 15% | 15% | 15% |
| Minor storm | 20% | 30% | 30% |
| Major-severe storm | 20% | 30% | 30% |
All times in UTC
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