what is a Jet Stream Forecast and how is it read?

Question

http://uk.weather.com/maps/geography/intleurope/natlanticjetstreamfcst24hr_large.html

Answer 1

The Jet Stream forecast is determined from the time dependent forecasts for the upper atmosphere (around 300 mb). When you look at the 300 mb forecasts you can pretty much see where the strongest core of winds is forecast to be. That is labeled the Jet Stream forecast.