Viewing archive of Thursday, 29 September 2011

Solar activity report

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

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 272 Issued at 2200Z on 29 Sep 2011

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

Solar activity has been low for the past 24 hours. Region 1305 (N13E16) has grown in aerial coverage and is now considered a Cso-type spot group with a beta-gamma magnetic configuration. The region produced a C1 event at 29/1023Z. Region 1302 (N13W16) produced a long duration C2/Sf at 29/1247Z. A Type II Radio Sweep with an estimated speed of 608 km/s was associated with this event. It is difficult to see in STEREO COR2 imagery but does appear to be Earth directed with an estimated plane-of-sky speed of 628 km/s. Further analysis will be done as LASCO imagery becomes available.
IB. Solar Activity Forecast
Solar activity is expected to be low for the next three days (30 September - 02 October) with a chance for isolated M-class and X-class events mainly from Region 1302.
IIA. Geophysical Activity Summary 28-2100Z to 29-2100Z
The geomagnetic field was mostly unsettled with isolated minor to major storm levels observed between 29/0000-0600Z due to substorming. Solar wind speeds jumped slightly to 600 km/s, in conjunction with an increase in temperature and density around 29/0030Z. Bt reached +13 nT and Bz dipped south with a maximum deviation of -10 nT.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be quiet to unsettled with a chance for isolated active periods early on day one (30 September) due to residual effects from the CME. Quiet to unsettled conditions are expected on day two (01 October) due to the arrival of a recurrent coronal hole high speed stream. Quiet to unsettled conditions are expected on day three (02 October).
III. Event Probabilities 30 Sep to 02 Oct
Class M60%60%60%
Class X30%30%30%
Proton15%15%15%
PCAFgreen
IV. Penticton 10.7 cm Flux
  Observed       29 Sep 137
  Predicted   30 Sep-02 Oct  140/140/140
  90 Day Mean        29 Sep 110
V. Geomagnetic A Indices
  Observed Afr/Ap 28 Sep  013/024
  Estimated     Afr/Ap 29 Sep  015/015
  Predicted    Afr/Ap 30 Sep-02 Oct  010/012-008/010-005/005
VI. Geomagnetic Activity Probabilities 30 Sep to 02 Oct
A. Middle Latitudes
Active20%10%05%
Minor storm05%01%01%
Major-severe storm01%01%01%
B. High Latitudes
Active25%10%05%
Minor storm05%05%01%
Major-severe storm01%01%01%

All times in UTC

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