NAVGEM (Navy Global Environmental Model) is a global numerical weather prediction computer model run by NOAA. It replaced NOGAPS as the prime model in the middle of February 2013 at the FNMOC Weather model synoptic site. NOGAPS: Global weather forecast model from the "Fleet Numerical Meteorology and Oceanography Center" (USA)
2 times per day, from 10:00 and 23:00 GMT
Greenwich Mean Time:
12:00 GMT = 13:00 BST
Sea Level Pressure in hPa (solid lines) and equivalent potential temperature at 850 hPa (dashed and coloured)
The equivalent potential temperature is calculated from the specific humidity (ratio of mass of the water vapor to
the total mass of the system) and the temperature, both at 850 hPa. Therefore, from this map one can read the fronts
even better than from the 'RH 700 hPa' or other maps.
Numerical weather prediction uses current weather conditions as input into mathematical models of the atmosphere to predict the weather. Although the first efforts to accomplish this were done in the 1920s, it wasn't until the advent of the computer and computer simulation that it was feasible to do in real-time. Manipulating the huge datasets and performing the complex calculations necessary to do this on a resolution fine enough to make the results useful requires the use of some of the most powerful supercomputers in the world. A number of forecast models, both global and regional in scale, are run to help create forecasts for nations worldwide. Use of model ensemble forecasts helps to define the forecast uncertainty and extend weather forecasting farther into the future than would otherwise be possible.
Wikipedia, Numerical weather prediction, http://en.wikipedia.org/wiki/Numerical_weather_prediction
(as of Feb. 9, 2010, 20:50 GMT).