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Solar activity report

Report of Solar-Geophysical Activity 2011 Apr 01 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 091 Issued at 2200Z on 01 Apr 2011

IA. Analysis of Solar Active Regions and Activity from 31-2100Z to 01-2100Z

Solar activity remained at low levels. Region 1178 (S17W36) produced a C1/Sf at 31/2221Z associated with a partial-halo CME that appeared to be directed southward, out of the ecliptic plane. Region 1178 decayed to a plage area during the period. Region 1176 (S16W65) produced C3 flares at 01/0156Z and 01/0354Z, each of which were associated with CME activity. This CME activity also appeared to be directed southward, out of the ecliptic plane. Region 1176 gradually decayed during the period with a loss of spot count and area. It was classified as an Fso-type with a simple beta magnetic configuration. Region 1183 (N17E01) showed a gradual increase in spot count and area and was classified as an Esi-type with a beta magnetic configuration. New Region 1184, a single-spot Axx-type, was numbered.
IB. Solar Activity Forecast
Solar activity is expected to be low during the period (02 - 04 April) with a slight chance for moderate activity (isolated M-class).
IIA. Geophysical Activity Summary 31-2100Z to 01-2100Z
Geomagnetic activity increased to quiet to active levels. ACE solar wind observations indicated the onset of a coronal hole high-speed stream (CH HSS) at approximately 01/1600Z. Velocities increased to a peak of 495 km/s at 01/1801Z. IMF changes associated with the CH HSS included increased Bt (peaks to 12 nT during 01/2000 - 2100Z) and intervals of southward Bz (maximum deflection -10 nT at 01/1628Z).
IIB. Geophysical Activity Forecast
Geomagnetic activity is expected to be at quiet to unsettled levels during day 1 (02 April) with a chance for active levels as CH HSS effects persist. Activity is expected to decrease to mostly quiet levels during days 2 - 3 (03 - 04 April) as CH HSS effects subside.
III. Event Probabilities 02 Apr to 04 Apr
Class M25%25%25%
Class X01%01%01%
IV. Penticton 10.7 cm Flux
  Observed       01 Apr 109
  Predicted   02 Apr-04 Apr  110/110/110
  90 Day Mean        01 Apr 098
V. Geomagnetic A Indices
  Observed Afr/Ap 31 Mar  002/003
  Estimated     Afr/Ap 01 Apr  010/013
  Predicted    Afr/Ap 02 Apr-04 Apr  007/007-005/005-005/005
VI. Geomagnetic Activity Probabilities 02 Apr to 04 Apr
A. Middle Latitudes
Minor storm05%05%01%
Major-severe storm01%01%01%
B. High Latitudes
Minor storm10%10%01%
Major-severe storm01%01%01%

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