Modèle:

Ensemble forecast charts of several different numerical weather prediction (NWP) models

Mise à jour:
2 times per day, from 05:00 and 17:00 UTC
Greenwich Mean Time:
12:00 UTC = 13:00 CET
Résolution:
Paramètre:
Mean relative humidity between ca. 3000 and 6000 m above the ground
Description:
This map presents the mean relative humidity between about 3000 and 6000m a.s.l. - equivalent to the atmospheric layer between 10,000 and 20,000 ft. This is the atmospheric region where middle and high stratus clouds form. They are typically fringing a warm ridge along the anticyclonic sector of a frontal zone. In general, middle and high stratus clouds are a good indicator for the run of the jet stream. Mean Relative Humidity in the layer between about 600 and 3000 m above ground
Spaghetti plots:
are a method of viewing data from an ensemble forecast.
A meteorological variable e.g. pressure, temperature is drawn on a chart for a number of slightly different model runs from an ensemble. The model can then be stepped forward in time and the results compared and be used to gauge the amount of uncertainty in the forecast.
If there is good agreement and the contours follow a recognisable pattern through the sequence then the confidence in the forecast can be high, conversely if the pattern is chaotic i.e resembling a plate of spaghetti then confidence will be low. Ensemble members will generally diverge over time and spaghetti plots are quick way to see when this happens.

Spaghetti plot. (2009, July 7). In Wikipedia, The Free Encyclopedia. Retrieved 20:22, February 9, 2010, from http://en.wikipedia.org/w/index.php?title=Spaghetti_plot&oldid=300824682
NWP:
La prévision numérique du temps (PNT) est une application de la météorologie et de l'informatique. Elle repose sur le choix d'équations mathématiques offrant une proche approximation du comportement de l'atmosphère réelle. Ces équations sont ensuite résolues, à l'aide d'un ordinateur, pour obtenir une simulation accélérée des états futurs de l'atmosphère. Le logiciel mettant en œuvre cette simulation est appelé un modèle de prévision numérique du temps.


Prévision numérique du temps. (2009, décembre 12). Wikipédia, l'encyclopédie libre. Page consultée le 20:48, février 9, 2010 à partir de http://fr.wikipedia.org/w/index.php?title=Pr%C3%A9vision_num%C3%A9rique_du_temps&oldid=47652746.