Viewing archive of Wednesday, 18 April 2012
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 2012 Apr 18 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 109 Issued at 2200Z on 18 Apr 2012IA. Analysis of Solar Active Regions and Activity from 17-2100Z to 18-2100Z Solar activity was low during the past 24 hours. New
Region 1463 (S26W36) produced several C-class and optical flares,
the largest a C8/Sf at 18/1239Z. An associated CME became visible in
STEREO COR2 imagery at 18/1309Z. Further analysis will be conducted
to determine effectiveness as imagery becomes available. Region 1463
also produced a C5 flare at 18/1706Z associated with Type II (est.
speed 621 km/s) and Type IV radio sweeps. No STEREO or LASCO imagery
was available for this event. Further analysis will also be
conducted on this event when imagery is available.
IB. Solar Activity Forecast
Solar activity is expected to be low
with a slight chance for an isolated M-class event for the next
three days (19-21 April).
IIA. Geophysical Activity Summary 17-2100Z to 18-2100Z
The geomagnetic field was quiet to unsettled during the past 24
hours. The increase in activity was due to a slight increase in
solar wind speeds (reaching approximately 475 km/s) and extended
periods of southward Bz.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be mostly quiet on day one (19 April). Quiet to
unsettled conditions are expected on day two (20 April) due to an
anticipated Solar Sector Boundary Crossing. A return to mostly quiet
conditions is expected on day three (21 April).
III. Event Probabilities 19 Apr to 21 Apr
| Class M | 15% | 15% | 15% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 18 Apr 122 Predicted 19 Apr-21 Apr 120/120/120 90 Day Mean 18 Apr 112
V. Geomagnetic A Indices
Observed Afr/Ap 17 Apr 008/010 Estimated Afr/Ap 18 Apr 008/008 Predicted Afr/Ap 19 Apr-21 Apr 004/005-007/008-004/005
VI. Geomagnetic Activity Probabilities 19 Apr to 21 Apr
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 10% | 25% | 10% |
| Minor storm | 01% | 10% | 01% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 15% | 15% | 15% |
| Minor storm | 15% | 30% | 15% |
| Major-severe storm | 10% | 30% | 10% |
All times in UTC
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