Viewing archive of Wednesday, 18 April 2012

Solar activity report

Report of Solar-Geophysical Activity 2012 Apr 18 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 109 Issued at 2200Z on 18 Apr 2012

IA. 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 M15%15%15%
Class X01%01%01%
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
Minor storm01%10%01%
Major-severe storm01%01%01%
B. High Latitudes
Minor storm15%30%15%
Major-severe storm10%30%10%

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