Model:

Updated:

4 times per day, from 08:00, 14:00, 20:00, and 00:00 UTC

Greenwich Mean Time:

12:00 UTC = 01:00 NZDT

Resolution:

0.1° x 0.1° (Europe)

0.5° x 0.5°

0.5° x 0.5°

Parameter:

Dew-point at 2m in hPa/h

Description:

The dew-point is the temperature air would have to be cooled to in order for
saturation to occur. The dew-point temperature assumes there is no change in
air pressure or moisture content of the air. Dew-point does not change with
temperature of the air; very much different from relative humidity.

The dew-point can be used to forecast low temperatures. The low will rarely fall far below the observed dew-point value in the evening (unless a front brings in a different air mass). Once the temperature drops to the dew-point, latent heat must be released to the atmosphere for the condensation process to take effect. This addition of heat offsets some or all of further cooling.

The dew-point can be used to forecast low temperatures. The low will rarely fall far below the observed dew-point value in the evening (unless a front brings in a different air mass). Once the temperature drops to the dew-point, latent heat must be released to the atmosphere for the condensation process to take effect. This addition of heat offsets some or all of further cooling.

Arpège:

Arpège

ARPEGE uses a set of primitive equations with a triangular spectral truncation on the horizontal, with a variable horizontal resolution, with a finite elements representation on the vertical and a “sigma-pressure” hybrid vertical coordinate. It also utilizes a temporal two time level semi-implicit semi-lagrangian scheme. The horizontal resolution of the ARPEGE model is around 7.5km over France and 37km over the Antipodes. It has 105 vertical levels, with the first level at 10m above the surface and an upper level at around 70km. Its time step is of 360 seconds.

ARPEGE uses a set of primitive equations with a triangular spectral truncation on the horizontal, with a variable horizontal resolution, with a finite elements representation on the vertical and a “sigma-pressure” hybrid vertical coordinate. It also utilizes a temporal two time level semi-implicit semi-lagrangian scheme. The horizontal resolution of the ARPEGE model is around 7.5km over France and 37km over the Antipodes. It has 105 vertical levels, with the first level at 10m above the surface and an upper level at around 70km. Its time step is of 360 seconds.

NWP:

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 UTC).

Wikipedia, Numerical weather prediction, http://en.wikipedia.org/wiki/Numerical_weather_prediction(as of Feb. 9, 2010, 20:50 UTC).