We can now determine whether contrails will be visible in our skies from a weather site.
This tool is VERY useful for us, so I will explain how to use it.
1. Go here - http://www.arl.noaa.gov/ready/cmet.html
2. Type in the 4 letter airport code where it says ICAO code (e.g. EPWA or EGLL, etc......)
OR you can simply click on the map on the location you want.
3. Under Interactive map, choose the time span you want. Usually 0-84h is more accurate.
4. Choose a date/time.
5.Under Meterological fields choose Temperature (3D) in section 1. Then choose a level either 200, 250, or 300mb. The choose Color Filled in contour type and in interval put '1'.
6. Type in the six letter code and press go.
7. Now you have your map. For a simple guide when using 250mb the orange means no contrails, the blue means contrails will be visible.
At 250mb, if the temperature is -58°C there is a 95% chance of contrails. If the teperature is -45°C there is 5% of contrails happening.
A more detailed explanation can be found here - http://www.skystef.be/monthly-weatherpicture-0709.htm
ContrailsUK
