Viewing archive of Friday, 2 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 02 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 245 Issued at 2200Z on 02 Sep 2011

IA. Analysis of Solar Active Regions and Activity from 01-2100Z to 02-2100Z

Solar activity was at low levels due a to C1/Sf flare at 02/1516Z from Region 1281 (S20E01). During the period, the region decayed slightly in area and spot count and remained a D-type, bi-polar spot group. Region 1283 (N13E37) produced an impulsive B8/Sf flare at 02/0852Z. The region showed penumbral development in the trailer spots and was classified as a D-type, bi-polar spot group. Region 1282 (N25W40) indicated an increase in area and longitudinal extent and was classified as an E-type, bi-polar spot group. A CME was observed lifting off the SE limb, first seen in SOHO LASCO/C2 imagery at 02/0748Z. A plane-of-sky speed was estimated at 375 km/s. The source of this CME appears to have originated from a filament channel centered near S28E42. Material motion was first observed on SDO/AIA 193 imagery at 02/0554Z. At this time, there does not appear to be an Earthward-directed component.
IB. Solar Activity Forecast
Solar activity is expected to be low through the period (03 - 05 September) with a slight chance for M-class activity.
IIA. Geophysical Activity Summary 01-2100Z to 02-2100Z
The geomagnetic field was quiet. Solar wind speeds, as measured at the ACE spacecraft, were steady below 300 km/s through the period. A phi angle change from negative (toward) to positive (away) was observed at approximately 02/0900Z. The Bz component of the interplanetary magnetic field was predominately negative through the period at about -4 nT.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be at quiet to unsettled levels, with a slight chance for active periods, on days one and two (03 - 04 September). This increase in activity is due to a recurrent coronal hole high speed stream expected to rotate into a geoeffective position early on 03 September. By day three (05 September), field activity is expected to return to mostly quiet levels.
III. Event Probabilities 03 Sep to 05 Sep
Class M10%10%10%
Class X01%01%01%
Proton01%01%01%
PCAFGreen
IV. Penticton 10.7 cm Flux
  Observed       02 Sep 115
  Predicted   03 Sep-05 Sep  115/115/110
  90 Day Mean        02 Sep 097
V. Geomagnetic A Indices
  Observed Afr/Ap 01 Sep  001/003
  Estimated     Afr/Ap 02 Sep  003/005
  Predicted    Afr/Ap 03 Sep-05 Sep  008/008-008/008-005/005
VI. Geomagnetic Activity Probabilities 03 Sep to 05 Sep
A. Middle Latitudes
Active20%20%15%
Minor storm05%05%01%
Major-severe storm01%01%01%
B. High Latitudes
Active25%25%20%
Minor storm10%10%05%
Major-severe storm01%01%01%

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