Solar activity report

Viewing archive of Friday, 29 April 2011

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 2011 Apr 29 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

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 M	05%	05%	05%
Class X	01%	01%	01%
Proton	01%	01%	01%
PCAF	green

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
Active	35%	40%	35%
Minor storm	10%	10%	10%
Major-severe storm	01%	01%	01%

B. High Latitudes
Active	40%	45%	40%
Minor storm	10%	15%	15%
Major-severe storm	01%	05%	05%

All times in UTC

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G1 - Minor geomagnetic storm

Observed Kp: 5
Threshold reached: 22:46 UTC

The solar wind speed is currently moderately high (577.8 km/sec.)

The strength of the interplanetary magnetic field is moderate (19.17nT), the direction is North (4.86nT).

The Disturbance Storm Time index predicts moderate storm conditions right now (-58nT)

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