Viewing archive of Thursday, 28 July 2011

Solar activity report

Report of Solar-Geophysical Activity 2011 Jul 28 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 209 Issued at 2200Z on 28 Jul 2011

IA. Analysis of Solar Active Regions and Activity from 27-2100Z to 28-2100Z

Solar activity was low. Region 1260 (N19E17) produced multiple C-flares during the period, the largest a C5 at 1212Z. Region 1260 increased in magnetic complexity and is classified as a Eac spot group with a Beta-Gamma-Delta magnetic classification. Region 1261 (N15E49) has exhibited slight rotational motion and is classified a Dko with a Beta magnetic classification. Region 1262 (N16W49) has decayed to a simple Axx group. New Regions 1263 (N18E73) and 1264 (S31E50) were numbered today.
IB. Solar Activity Forecast
Solar activity is expected to continue at predominantly low levels with a chance for M-class flares from Region 1260.
IIA. Geophysical Activity Summary 27-2100Z to 28-2100Z
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 mostly quiet for the first two days (29-30 July). On day three (31 July) activity is expected to increase to unsettled levels with the chance for active periods due to effects from a coronal hole high speed stream.
III. Event Probabilities 29 Jul to 31 Jul
Class M40%40%40%
Class X05%05%05%
IV. Penticton 10.7 cm Flux
  Observed       28 Jul 107
  Predicted   29 Jul-31 Jul  110/110/110
  90 Day Mean        28 Jul 095
V. Geomagnetic A Indices
  Observed Afr/Ap 27 Jul  002/004
  Estimated     Afr/Ap 28 Jul  004/005
  Predicted    Afr/Ap 29 Jul-31 Jul  005/005-005/005-012/012
VI. Geomagnetic Activity Probabilities 29 Jul to 31 Jul
A. Middle Latitudes
Minor storm01%01%15%
Major-severe storm01%01%05%
B. High Latitudes
Minor storm01%01%20%
Major-severe storm01%01%10%

<< 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:2020/02/19Kp5 (G1)
Number of spotless days in 2020:77
Current stretch spotless days:6

This day in history*

Solar flares
*since 1994

Social networks