Viewing archive of Saturday, 3 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 03 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 246 Issued at 2200Z on 03 Sep 2011

IA. Analysis of Solar Active Regions and Activity from 02-2100Z to 03-2100Z

Solar activity was at low levels due to several C-class events observed during the period. As it approached the west limb, Region 1280 (N12W78) produced three C-class flares, the largest a C2/Sf at 03/1736Z. Region 1281 (S19W10) produced a C2/Sf at 03/0756Z. Region 1282 (N23W52) indicated decay in its intermediate spots, but developed a delta magnetic structure in the large leader spot. Two new regions were numbered during the period. New Region 1286 (N20W57) rapidly emerged as an eight spot D-type group and produced a C1 x-ray event at 03/1846Z. New Region 1287 (S30E64) rotated onto the disk as a three spot C-type group. All remaining regions were quiet and stable. No Earth-directed CMEs were detected during the period.
IB. Solar Activity Forecast
Solar activity is expected to be low for the next three days (04 - 06 September) with a slight chance for M-class activity.
IIA. Geophysical Activity Summary 02-2100Z to 03-2100Z
The geomagnetic field was at quiet to unsettled levels with an isolated active period observed at Boulder between 03/0900Z - 1200Z. At about 03/0100Z, observations from the ACE spacecraft indicated an increase in temperature, density and wind speed. These increases, coupled with a brief period of southward Bz to -12nT and an increase in Bt to 13nT, were indicative of a co-rotating interaction region in advance of a coronal hole high speed stream. During the period, wind speed increased from about 275 km/s to near 425 km/s while Bz generally fluctuated between +/- 5 nT.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be at quiet to unsettled levels, with a chance for isolated active periods, on day one (04 September) as the coronal hole high speed stream (CH HSS) persists. Days two and three (05 - 06 September) will see a return to mostly quiet levels as the CH HSS moves out of a geoeffective position.
III. Event Probabilities 04 Sep to 06 Sep
Class M15%15%15%
Class X01%01%01%
Proton01%01%01%
PCAFGreen
IV. Penticton 10.7 cm Flux
  Observed       03 Sep 119
  Predicted   04 Sep-06 Sep  120/120/115
  90 Day Mean        03 Sep 097
V. Geomagnetic A Indices
  Observed Afr/Ap 02 Sep  001/003
  Estimated     Afr/Ap 03 Sep  011/011
  Predicted    Afr/Ap 04 Sep-06 Sep  008/008-005/005-005/005
VI. Geomagnetic Activity Probabilities 04 Sep to 06 Sep
A. Middle Latitudes
Active20%15%10%
Minor storm05%01%01%
Major-severe storm01%01%01%
B. High Latitudes
Active25%20%15%
Minor storm10%05%01%
Major-severe storm01%01%01%

All times in UTC

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