Viewing archive of Sunday, 4 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 04 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 247 Issued at 2200Z on 04 Sep 2011

IA. Analysis of Solar Active Regions and Activity from 03-2100Z to 04-2100Z

Solar activity was at moderate levels due to an M3 x-ray event observed on the west limb at 04/1145Z. This event originated from the west limb spot group complex consisting of Regions 1280 (N13W91) and 1286 (N20W75). Close proximity to the limb made precise analysis of the flare location difficult. Associated with the M3 event was a west limb CME, first observed in LASCO C2 imagery at 04/1212Z. A plane-of-sky speed was estimated at about 400 km/s. Preceding this event was another west limb CME, first observed in LASCO C2 imagery at 04/0912Z. A plane-of-sky speed was estimated at about 150 km/s. Analysis of the potential geoeffectiveness of these CMEs is ongoing. Numerous C-class flares were also observed during the period from this area of the west limb. Region 1287 (S32E51) produced a C1 x-ray event early in the period at 03/2212Z. This region showed minor growth in area while the remaining regions on the disk indicated a slight decay in area coupled with loss of spots.
IB. Solar Activity Forecast
Solar activity is expected to be low for the next three days (05 - 07 September). A chance for additional M-class activity exists through 06 September.
IIA. Geophysical Activity Summary 03-2100Z to 04-2100Z
The geomagnetic field was at quiet to unsettled levels. Observations from the ACE spacecraft indicated wind speeds varied predominately between 350 to 400 km/s. The Bz component of the interplanetary magnetic field did not vary much beyond +/- 5 nT during the period.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be at quiet to unsettled levels for day one (05 September) due to continuing effects from a coronal hole high speed stream (CH HSS). By days two and three (06 - 07 September), the field is expected to be at mostly quiet levels as the CH HSS moves out of a geoeffective position.
III. Event Probabilities 05 Sep to 07 Sep
Class M25%15%05%
Class X01%01%01%
Proton01%01%01%
PCAFGreen
IV. Penticton 10.7 cm Flux
  Observed       04 Sep 119
  Predicted   05 Sep-07 Sep  120/115/105
  90 Day Mean        04 Sep 098
V. Geomagnetic A Indices
  Observed Afr/Ap 03 Sep  009/013
  Estimated     Afr/Ap 04 Sep  007/008
  Predicted    Afr/Ap 05 Sep-07 Sep  005/008-005/005-005/005
VI. Geomagnetic Activity Probabilities 05 Sep to 07 Sep
A. Middle Latitudes
Active15%10%10%
Minor storm01%01%01%
Major-severe storm01%01%01%
B. High Latitudes
Active20%15%15%
Minor storm05%01%01%
Major-severe storm01%01%01%

All times in UTC

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