Modèle:
RAP (Rapid Refresh)
Mise à jour:
24 times per day, from 00:00 - 23:00 UTC
Greenwich Mean Time:
12:00 UTC = 13:00 CET
Résolution:
0.128° x 0.123°
Description:
The Lifted Index (LI) is defined as a rising parcel's temperature when it reaches
the 500 millibars level (at about 5,500m or 18,000 feet asl), subtracted from
the actual temperature of the environmental air at 500 mbar. If the Lifted
Index is a large negative number, then the parcel will be much warmer than its
surroundings, and will continue to rise. Thunderstorms are fueled by strong rising air, thus the
Lifted Index is a good measurement of the atmosphere's potential to produce
severe thunderstorms.
The Lifted Index (LI) |
RANGE IN K |
COLOR |
AMOUNT OF INSTABILITY |
THUNDERSTORM PROBABILITY |
more than 11 |
BLUE |
Extremely stable conditions |
Thunderstorms unlikely |
8 to 11 |
LIGHT BLUE |
Very stable conditions |
Thunderstorms unlikely |
4 to 7 |
GREEN |
Stable conditions |
Thunderstorms unlikely |
0 to 3 |
LIGHT GREEN |
Mostly stable conditions |
Thunderstorm unlikely |
-3 to -1 |
YELLOW |
Slightly unstable |
Thunderstorms possible |
-5 to -4 |
ORANGE |
Unstable |
Thunderstorms probable |
-7 to -6 |
RED |
Highly unstable |
Severe thunderstorms possible |
less than -7 |
VIOLET |
Extremely unstable |
Violent thunderstorms, tornadoes possible |
RAP:
RAP
The Rapid Refresh (RAP) is a NOAA/NCEP operational weather prediction system comprised primarily of a numerical forecast model and analysis/assimilation system to initialize that model. It is run with a horizontal resolution of 13 km and 50 vertical layers.
,
The RAP was developed to serve users needing frequently updated short-range weather forecasts, including those in the US aviation community and US severe weather forecasting community. The model is run for every hour of day and is integrated to 18 hours for each cycle. The RAP uses the ARW core of the WRF model and the Gridpoint Statistical Interpolation (GSI) analysis - the analysis is aided with the assimilation of cloud and hydrometeor data to provide more skill in short-range cloud and precipitation forecasts.
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.