Viewing archive of Friday, 29 April 2011

Solar activity report

Report of Solar-Geophysical Activity 2011 Apr 29 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 119 Issued at 2200Z on 29 Apr 2011

IA. Analysis of Solar Active Regions and Activity from 28-2100Z to 29-2100Z

Solar activity has been at low levels for the past 24 hours. Region 1203 (N18E64) produced the largest event of the period, a C3 flare at 29/0026Z. Region 1200 (S17E05) regained spots and has developed into a beta group.
IB. Solar Activity Forecast
Solar activity is expected to be at low levels for the next two days (30 April - 01 May). Very low to low levels are expected on day three (02 May) as Regions 1199 (N18W62) and 1195 (S15W65) rotate off the west limb.
IIA. Geophysical Activity Summary 28-2100Z to 29-2100Z
The geomagnetic field has been at predominantly quiet levels for the past 24 hours. However, late in the summary period, unsettled conditions were observed. Measurements by the ACE spacecraft showed an increase in solar wind speed from around 350 - 450 km/s. The total interplanetary magnetic field increased from 5 - 18 nT over the period with the negative component peaking at -10 nT. These changes in solar wind indicate the arrival of a coronal hole high-speed stream (CH HSS).
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be unsettled to active with isolated periods at minor storm levels for the next three days (30 April - 02 May) as a CH HSS becomes geoeffective.
III. Event Probabilities 30 Apr to 02 May
Class M05%05%05%
Class X01%01%01%
IV. Penticton 10.7 cm Flux
  Observed       29 Apr 110
  Predicted   30 Apr-02 May  110/105/105
  90 Day Mean        29 Apr 107
V. Geomagnetic A Indices
  Observed Afr/Ap 28 Apr  001/003
  Estimated     Afr/Ap 29 Apr  007/008
  Predicted    Afr/Ap 30 Apr-02 May  010/010-012/012-010/010
VI. Geomagnetic Activity Probabilities 30 Apr to 02 May
A. Middle Latitudes
Minor storm10%10%10%
Major-severe storm01%01%01%
B. High Latitudes
Minor storm10%15%15%
Major-severe storm01%05%05%

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