Viewing archive of Sunday, 29 May 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 May 29 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 149 Issued at 2200Z on 29 May 2011

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

Solar activity was moderate. At 29/1033Z, a long-duration M1/1F flare occurred from Region 1126 (S21E54). The flare was accompanied by a Type II (554 km/s shock velocity) radio emission and a CME was later visible in both SOHO/LASCO and STEREO COR2 imagery. The CME speed was estimated at 550 km/s using plane-of-sky measurements. The CME is not expected to be geoeffective, based on its origin. Region 1126 grew in area and spot count over the past 24 hours. Two magnetically simple new regions, 1127 (S19E69) and 1128 (N17E67), were numbered.
IB. Solar Activity Forecast
Solar activity is expected to be low to moderate. More C-class events are expected and there is a continued chance of an M-class event.
IIA. Geophysical Activity Summary 28-2100Z to 29-2100Z
The geomagnetic field ranged from unsettled to minor storm levels. Solar wind speed rose above 500 km/s early in the period and ranged between 700-800 km/s for the remainder. The Bz component of the interplanetary magnetic field fluctuated between +7 and -9 nT. At the same time the wind speed increased, temperature increased, density decreased and the Phi angle became negative. These observations were consistent with a geoeffective coronal hole high speed stream. The greater than 2 MeV electron flux at geosynchronous orbit reached high levels during the period.
IIB. Geophysical Activity Forecast
The goemagnetic field is expected to decline from predominantly unsettled to active levels on day 1 (30 May), to quiet to unsettled levels on days 2 and 3 (31 May - 01 Jun) as the coronal hole high speed stream wanes. There remains a chance for isolated minor storm periods at high latitudes on day 1.
III. Event Probabilities 30 May to 01 Jun
Class M40%40%40%
Class X05%05%05%
Proton05%05%05%
PCAFgreen
IV. Penticton 10.7 cm Flux
  Observed       29 May 111
  Predicted   30 May-01 Jun  110/110/110
  90 Day Mean        29 May 108
V. Geomagnetic A Indices
  Observed Afr/Ap 28 May  032/040
  Estimated     Afr/Ap 29 May  025/043
  Predicted    Afr/Ap 30 May-01 Jun  015/020-010/012-005/010
VI. Geomagnetic Activity Probabilities 30 May to 01 Jun
A. Middle Latitudes
Active25%10%05%
Minor storm10%05%01%
Major-severe storm01%01%01%
B. High Latitudes
Active35%20%05%
Minor storm20%10%01%
Major-severe storm10%05%01%

All times in UTC

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