Notes on GFS forecast maps
The Global Forecast System (GFS) is a National Centers for Environmental Prediction (NCEP)
weather forecast model that generates data for dozens of atmospheric and land-soil variables,
including temperatures, winds, precipitation, soil moisture, and atmospheric ozone concentration.
The system couples four separate models (atmosphere, ocean model, land/soil model, and sea ice) that work
together to accurately depict weather conditions.
GFS is a global model with a base horizontal resolution of 0.25° (28 kilometers) between grid points. The GFS is run 4 times a day, the temporal resolution covers analysis and forecasts out to 16 days.
GFS Europe: Jet Stream at 200 hPa
VERSIONE ITALIANA: CLICCA QUI
These maps show the jet stream at 200 hPa , i.e. the speed (in km/h) and the direction of the wind at 200 hPa. The jet stream
can be a few hundred kilometers wide and swings in the meridian direction giving rise to the so-called Rossby waves. Due to the
lower temperatures and therefore the higher density, in winter the jet stream is at a lower altitude than in the hot seansons, therefore
it is advisable to analyze the maps at 300 hPa (about 9000 m),
while in summer those at 200 hPa (about 11000 m).
On the top left is shown the UTC initialization time. UTC time is indicated with Z letter (Zulu Time). On the top right is shown the UTC forecast time.
The maps at 00Z, 06Z, 12Z and 18Z are updated respectively starting from 04.30 AM, 10:30 AM, 4:30 PM, 10.30 PM (CEST TIime).
Forecast model: Global Forecast System (GFS) with 0.5°x0.5° (lat x lon) spatial resolution.
NOTE: in central European countries, when solar time is in effect, the CET time is used, which is equal to UTC +1 hour, while when daylight saving time is in effect, the CEST time is used, which is equal to UTC +2 hours. Right now it is 3:55 UTC.