Viewing archive of Tuesday, 17 April 2012

Solar activity report

Report of Solar-Geophysical Activity 2012 Apr 17 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 108 Issued at 2200Z on 17 Apr 2012

IA. Analysis of Solar Active Regions and Activity from 16-2100Z to 17-2100Z

Solar activity has been low for the past 24 hours. A long duration C1 flare was observed from new Region 1461 (N13E66) at 17/0809Z. An associated CME became visible in LASCO C2 imagery at 17/0800Z but does not appear to be Earth-directed. A filament eruption occurred at approximately 17/1330Z near N24W40. The associated CME was first visible in LASCO C2 imagery at 17/1424Z but is not expected to be geoeffective. New Region 1460 (N16E26) was also numbered overnight and is considered a Dso-beta type spot group. Region 1459 (S15E40) has shown a significant decrease in areal coverage and is now a Dao-beta type spot group.
IB. Solar Activity Forecast
Solar activity is expected to be low with a slight chance for an M-class flare for the next three days (18-20 April).
IIA. Geophysical Activity Summary 16-2100Z to 17-2100Z
The geomagnetic field was mostly quiet during the past 24 hours. The greater than 2 MeV electron flux at geosynchronous orbit reached high levels during the period.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be mostly quiet on days one and two (18-19 April). Quiet to unsettled conditions are expected with a chance for isolated active periods on day three (20 April) due to a recurrent Solar Sector Boundary Crossing (SSBC).
III. Event Probabilities 18 Apr to 20 Apr
Class M20%15%10%
Class X01%01%01%
IV. Penticton 10.7 cm Flux
  Observed       17 Apr 114
  Predicted   18 Apr-20 Apr  115/115/110
  90 Day Mean        17 Apr 112
V. Geomagnetic A Indices
  Observed Afr/Ap 16 Apr  005/005
  Estimated     Afr/Ap 17 Apr  006/008
  Predicted    Afr/Ap 18 Apr-20 Apr  004/005-004/005-007/008
VI. Geomagnetic Activity Probabilities 18 Apr to 20 Apr
A. Middle Latitudes
Minor storm01%01%10%
Major-severe storm01%01%01%
B. High Latitudes
Minor storm15%15%30%
Major-severe storm10%10%30%

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