This page contains a dynamic collection of propagation information gathered from many different sources. This data is extremely useful for ham radio operators and shortwave listeners to help determine whether or not long distance radio communications are possible.

The current time is: 21:01 UTC on Saturday, September 23, 2023

Current Solar Indices from WWV
23-Sep-2023 at 1805 UTC
SFI = 176   A = 8   K = 1
Conditions during the last 24 hours
Space weather for the past 24 hours has been minor.
Radio blackouts reaching the R1 level occurred.
Forecast for the next 24 hours
Space weather for the next 24 hours is predicted to be minor.
Geomagnetic storms reaching the G1 level are likely. Radio blackouts reaching the R1 level are likely.

Solar Wind Data
Provides solar wind velocity and energetic particle intensity
Updated at: 2047Z on September 23, 2023

 Velocity (km/s):  295.0 
 Density (protons/cm3):  0.1 

(ACE satellite solar wind data has been intermittent)

Penticton Observatory SFI Measurement
WWV only updates its SFI reading once a day at 2100Z
The Penticton solar observatory takes measurements at 1700Z, 2000Z, and 2300Z
(WWV uses the 2000Z Penticton measurement)

 The Penticton Observatory SFI value on 23-Sep-2023 at 1700Z was:  174 

Three Day SFI and A-index Forecast
(updated daily after 2200Z)

This report issued on Sep 22, 2023 at 2200Z

  Date     SFI     A-index  
  23 Sep   178 18
  24 Sep   175 22
  25 Sep   172 15

Solar Activity Forecast
R1-R2 (Minor-Moderate) radio blackouts are likely, and there is a slight chance R3 (Strong) or greater radio blackouts over 22-24 Sep.
Geophysical Activity Forecast
The geomagnetic field is expected to be at mostly unsettled to active levels on 22 Sep due to negative polarity CH HSS onset. G1 (Minor) geomagnetic storming is likely 23-24 Sep due to first shock and glancing influences from the 20 Sep CME followed by the arrival of the 21 Sep CME by late on the 24th.

Recent Major Solar Flare Activity
(usually reported within 30 minutes of event peak)

  Date     Time     Magnitude  
  22-Sep-2023     2300Z     M1.9  
  22-Sep-2023     1715Z     M1.5  
  22-Sep-2023     1623Z     M1.4  
  22-Sep-2023     0336Z     M1.2  
  21-Sep-2023     1254Z     M8.7  
  20-Sep-2023     1419Z     M8.2  
  19-Sep-2023     2014Z     M4.0  
  19-Sep-2023     0938Z     M1.8  
  19-Sep-2023     0355Z     M1.1  

NOAA (American) Sunspot Number
This number is reported daily around 0225Z and reports
the number of sunspots observed in the previous 24 hour period

 The NOAA Sunspot number for 22-Sep-2023 was:  184 

 Most recent five days (oldest first): 94  139  143  159  159   

GOES-14 Background X-ray Flux
This value is reported daily around 0225Z and reports the
average background x-ray flux level as measured by the GOES-14 satellite

 The GOES-14 Background X-ray Flux level on 22-Sep-2023 was:  * 

 Most recent five days (oldest first): *  *  *  *  *   

Auroral Activity

Aurora (also known as "aurora borealis" or "northern lights") is caused by interaction between the Earth's magnetic field and the solar wind (a mix of charged particles blowing away from the sun).  During storms, enough of these charged particles make it through to the Earth's upper atmosphere that they interact with the earths natural magnetic field lines.  When enough of these particles collide, energy is released in the form of auroral light.  In addition to creating a pretty light show (mostly in upper latitudes), ham radio signals scatter off of these particles and can greatly enhance propagation on the VHF and UHF ham radio bands. High levels of aurora can also make HF ham radio propagation via polar routes difficult.

Northern Hemisphere
Auroral Activity

Northern Hemisphere Aurora


Southern Hemisphere
Auroral Activity

Southern Hemisphere Aurora


Click on thumbnails to view a larger image
Images courtesy of the NOAA Auroral Activity site

Solar X-ray Flux

This chart shows X-ray flux levels as measured by the GOES-13 and GOES-15 satellites.  The measurements (shown in red) are used to issue alerts when X-ray flux levels exceed certain levels.  Spikes on the chart correspond to solar flares.  Flares are considered "significant" when flux levels rise above the "M" level (as shown on the right side of the chart).  These large flares can often wipe out the ham radio and shortwave bands almost immediately and it can take minutes to hours for the bands to recover.  If the ham radio bands seem to go dead all of a sudden, it is always a good idea to check this chart to see if a large flare has occurred recently.

The Solar X-ray Flux graph is temporarily broken.
Click here to view it on the NOAA site

Dynamically updating plots:
1-minute and 5-minute X-ray    K-index
   Proton Flux   Electron Flux   GOES Magnetometer

Grey Line Map

The grey line is a band around the Earth that separates the daylight from darkness.  Radio propagation along the grey line is very efficient.  One major reason for this is that the D layer, which absorbs HF signals, disappears rapidly on the sunset side of the grey line, and it has not yet built upon the sunrise side.  Ham radio operators and shortwave listeners can optimize long distance communications to various areas of the world by monitoring this area as it moves around the globe.  This map shows the current position of the grey line terminator.

Grey Line Map

Click here to show a dynamically updating Grey Line map

MUF map

The following map shows Maximum Usable Frequencies (MUFs) for 3000 kilometer radio signal paths. The grey line position is also provided.


Image courtesy of the KC2G propaation pages

Current Sun Images

The images below are current views of the sun shown at different wavelengths of light as taken by SOHO and the Yohkoh soft-Xray telescope. Generally, more bright regions on the disk indicates more solar activity, which usually leads to higher flux levels (which also often leads to better ham radio and shortwave propagation).  Click on any thumbnail to view a larger image.

SOHO - 17.1nm

SOHO 17.1nm

SOHO - 19.5nm

SOHO 19.5nm

SOHO - 28.4nm

SOHO 28.4nm

SOHO - 30.4nm

SOHO 30.4nm

Sometimes you may see the text "CCD Bakeout" instead of the images.  This occurs when NASA does routine maintenance and calibration on the cameras.  For a more technical explanation, read NASA CCD Bakeout explanation.

Images courtesy of the SDAC at the NASA Goddard Space Flight Center

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Layout and dynamic reports created by amateur radio N6RT

Comments or Questions? Email [email protected]