Viewing archive of Tuesday, 17 May 2011

Solar activity report

Report of Solar-Geophysical Activity 2011 May 17 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 137 Issued at 2200Z on 17 May 2011

IA. Analysis of Solar Active Regions and Activity from 16-2100Z to 17-2100Z

Solar activity was very low during the past 24 hours. Regions 1208 (N09W78) and 1214 (S24W24) produced several B-class events. All other regions on the disk remained relatively quiet and stable. A filament erupted near N13W07 and an associated CME became visible on STEREO COR2 imagery at 17/0709Z. The CME was well above the ecliptic plane and is not expected to be geoeffective.
IB. Solar Activity Forecast
Solar activity is expected to be very low with a chance for C-class activity for the next three days (18-20 May).
IIA. Geophysical Activity Summary 16-2100Z to 17-2100Z
The geomagnetic field was mostly quiet during the past 24 hours. Solar wind velocities gradually decreased from approximately 620 km/s to 540 km/s indicating the effects from the coronal hole high-speed stream (CH HSS) that has been influencing the field for the past few days are beginning to subside.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be mostly quiet for the next three days (18-20 May).
III. Event Probabilities 18 May to 20 May
Class M01%01%01%
Class X01%01%01%
IV. Penticton 10.7 cm Flux
  Observed       17 May 092
  Predicted   18 May-20 May  092/095/095
  90 Day Mean        17 May 109
V. Geomagnetic A Indices
  Observed Afr/Ap 16 May  010/012
  Estimated     Afr/Ap 17 May  008/008
  Predicted    Afr/Ap 18 May-20 May  005/005-005/005-005/005
VI. Geomagnetic Activity Probabilities 18 May to 20 May
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:2019/10/26Kp5 (G1)
Number of spotless days in 2019:237
Current stretch spotless days:10

This day in history*

Solar flares
*since 1994

Social networks