Viewing archive of Wednesday, 27 July 2011

Solar activity report

Report of Solar-Geophysical Activity 2011 Jul 27 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 208 Issued at 2200Z on 27 Jul 2011

IA. Analysis of Solar Active Regions and Activity from 26-2100Z to 27-2100Z

Solar activity was moderate. Region 1260 (N18E30) produced a M1/1n flare at 1607Z as well as numerous C-class flares during the past 24 hours. This region showed some magnetic complexity (magnetic class beta-gamma) and changed steadily throughout the day. Region 1261 (N15E60) is the largest group on the disk (250 millionths) but is a simple magnetic beta group and only produced one subflare during the day. New Region 1262 (N16W38) was assigned and is a small D-type group with a weak delta configuration in the trailing portion of the group. Despite its magnetic complexity 1262 did not produce any flares. The eruption of a filament from the northeast quadrant was observed at about 0620Z and was associated with a faint, slow coronal mass ejection off the northeast limb as observed by the LASCO C2 coronagraph beginning at 0642Z.
IB. Solar Activity Forecast
Solar activity is expected to be predominantly low but there is a chance for additional isolated M-class flares from Region 1260.
IIA. Geophysical Activity Summary 26-2100Z to 27-2100Z
The geomagnetic field was quiet. The greater than 2 MeV electron flux at geosynchronous orbit reached high levels during the period.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be quiet for the next three days (28-30 July). Recent analysis from Stereo-B and solar imagery suggest that the previously anticipated high speed stream from a coronal hole is most likely to start affecting Earth on 31 July.
III. Event Probabilities 28 Jul to 30 Jul
Class M40%40%40%
Class X01%01%01%
IV. Penticton 10.7 cm Flux
  Observed       27 Jul 099
  Predicted   28 Jul-30 Jul  100/100/105
  90 Day Mean        27 Jul 095
V. Geomagnetic A Indices
  Observed Afr/Ap 26 Jul  005/005
  Estimated     Afr/Ap 27 Jul  005/005
  Predicted    Afr/Ap 28 Jul-30 Jul  005/005-005/005-005/005
VI. Geomagnetic Activity Probabilities 28 Jul to 30 Jul
A. Middle Latitudes
Minor storm01%01%01%
Major-severe storm01%01%01%
B. High Latitudes
Minor storm01%01%01%
Major-severe storm01%01%01%

<< Go to daily overview page

Latest news


A lot of people come to SpaceWeatherLive to follow the Sun's activity or if there is aurora to be seen, but with more traffic comes higher server costs. Consider a donation if you enjoy SpaceWeatherLive so we can keep the website online!


Space weather facts

Last X-flare:2017/09/10X8.2
Last M-flare:2017/10/20M1.0
Last geomagnetic storm:2020/04/20Kp5 (G1)
Number of spotless days in 2020:112
Current stretch spotless days:20

This day in history*

Solar flares
*since 1994

Social networks