<div class="eI0">
<div class="eI1">Modèle:</div>
<div class="eI2"><h2><a href="http://en.wikipedia.org/wiki/European_Centre_for_Medium-Range_Weather_Forecasts" target="_blank">ECMWF</a>: Global weather forecast model from the "European Centre for Medium-Range Weather Forecasts". ECMWF is now running its own Artificial Intelligence/Integrated Forecasting System (AIFS) as part of its experiment suite. These machine-learning-based models are very fast, and they produce a 10-day forecast with 6-hourly time steps in approximately one minute. </h2></div>
</div>
<div class="eI0">
<div class="eI1">Mise à jour:</div>
<div class="eI2">4 times per day, from 3:30, 09:30, 15:30 and 21:30 UTC</div>
</div>
<div class="eI0">
<div class="eI1">Greenwich Mean Time:</div>
<div class="eI2">12:00 UTC = 14:00 CEST</div>
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<div class="eI0">
<div class="eI1">Résolution:</div>
<div class="eI2">0.25° x 0.25°</div>
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<div class="eI0">
<div class="eI1">Paramètre:</div>
<div class="eI2">Lifted Index</div>
</div>
<div class="eI0">
<div class="eI1">Description:</div>
<div class="eI2">
<!--begin info text LI-->
<p>
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.
</p>
<p>
<!--begin LI table-->
<body>
<table width="400" cellspacing="0" cellpadding="0" border="0">
<tr height="30" bgcolor="#E5E5E5"><!-- Row 1 -->
<td colspan="4"><font size="3" face="Arial, Helvetica" color="#0000FF">The Lifted Index (LI)</td>
</tr>
<tr height="30"><!-- Row 2 -->
<td width="17%" valign="top"><font size="1" face="Arial, Helvetica"><center>RANGE IN K</center></td>
<td bgcolor="#E5E5E5" width="20%" valign="top"><font size="1" face="Arial, Helvetica"><center>COLOR</center></td>
<td width="30%" valign="top"><font size="1" face="Arial, Helvetica"><center>AMOUNT OF INSTABILITY</center></td>
<td widht="33%" valign="top"><font size="1" face="Arial, Helvetica"><center>THUNDERSTORM PROBABILITY</center></td>
</tr>
<tr height="25" bgcolor="#E5E5E5"><!-- Row 3 -->
<td valign="top"><font size="1" face="Arial, Helvetica"><center>more than 11</center></td>
<td valign="top"><font size="1" face="Arial, Helvetica" color="#00A1E6"><center>BLUE</center></td>
<td valign="top"><font size="1" face="Arial, Helvetica"><center>Extremely stable conditions</center></td>
<td valign="top"><font size="1" face="Arial, Helvetica"><center>Thunderstorms unlikely</center></td>
</tr>
<tr height="25"><!-- Row 4 -->
<td valign="top"><font size="1" face="Arial, Helvetica"><center>8 to 11</center></td>
<td bgcolor="#E5E5E5" valign="top"><font size="1" face="Arial, Helvetica" color="#00C7C7"><center>LIGHT BLUE</center></td>
<td valign="top"><font size="1" face="Arial, Helvetica"><center>Very stable conditions</center></td>
<td valign="top"><font size="1" face="Arial, Helvetica"><center>Thunderstorms unlikely</center></td>
</tr>
<tr height="25" bgcolor="#E5E5E5"><!-- Row 5 -->
<td valign="top"><font size="1" face="Arial, Helvetica"><center>4 to 7</center></td>
<td bgcolor="#E5E5E5" valign="top"><font size="1" face="Arial, Helvetica" color="#00D18C"><center>GREEN</center></td>
<td valign="top"><font size="1" face="Arial, Helvetica"><center>Stable conditions</center></td>
<td valign="top"><font size="1" face="Arial, Helvetica"><center>Thunderstorms unlikely</center></td>
</tr>
<tr height="25"><!-- Row 6 -->
<td valign="top"><font size="1" face="Arial, Helvetica"><center>0 to 3</center></td>
<td bgcolor="#E5E5E5"valign="top"><font size="1" face="Arial, Helvetica" color="#A1E633"><center>LIGHT GREEN</center></td>
<td valign="top"><font size="1" face="Arial, Helvetica"><center>Mostly stable conditions</center></td>
<td valign="top"><font size="1" face="Arial, Helvetica"><center>Thunderstorm unlikely</center></td>
</tr>
<tr height="25" bgcolor="#E5E5E5"><!-- Row 7 -->
<td valign="top"><font size="1" face="Arial, Helvetica"><center>-3 to -1</center></td>
<td bgcolor="#E5E5E5" valign="top"><font size="1" face="Arial, Helvetica" color="#E6DC33"><center>YELLOW</center></td>
<td valign="top"><font size="1" face="Arial, Helvetica"><center>Slightly unstable</center></td>
<td valign="top"><font size="1" face="Arial, Helvetica"><center>Thunderstorms possible</center></td>
</tr>
<tr height="25"><!-- Row 8 -->
<td valign="top"><font size="1" face="Arial, Helvetica"><center>-5 to -4</center></td>
<td bgcolor="#E5E5E5" valign="top"><font size="1" face="Arial, Helvetica" color="#F08229"><center>ORANGE</center></td>
<td valign="top"><font size="1" face="Arial, Helvetica"><center>Unstable</center></td>
<td valign="top"><font size="1" face="Arial, Helvetica"><center>Thunderstorms probable</center></td>
</tr>
<tr height="25" bgcolor="#E5E5E5"><!-- Row 9 -->
<td valign="top"><font size="1" face="Arial, Helvetica"><center>-7 to -6</center></td>
<td bgcolor="#E5E5E5" valign="top"><font size="1" face="Arial, Helvetica" color="#F00000"><center>RED</center></td>
<td valign="top"><font size="1" face="Arial, Helvetica"><center>Highly unstable</center></td>
<td valign="top"><font size="1" face="Arial, Helvetica"><center>Severe thunderstorms possible</center></td>
</tr>
<tr height="25"><!-- Row 10 -->
<td valign="top"><font size="1" face="Arial, Helvetica"><center>less than -7</td>
<td bgcolor="#E5E5E5" valign="top"><font size="1" face="Arial, Helvetica" color="#FF00FF"><center>VIOLET</td>
<td valign="top"><font size="1" face="Arial, Helvetica"><center>Extremely unstable</td>
<td valign="top"><font size="1" face="Arial, Helvetica"><center>Violent thunderstorms, tornadoes possible</td>
</tr>
</table>
<!--end LI table-->
</p>
<!--end info_text LI-->
</div>
</div>
<div class="eI0">
<div class="eI1">NWP:</div>
<div class="eI2">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.<br><br>
<br>Prévision numérique du temps. (2009, décembre 12). Wikipédia, l'encyclopédie libre. Page consultée le 20:48, février 9, 2010 à partir de <a href="http://fr.wikipedia.org/w/index.php?title=Pr%C3%A9vision_num%C3%A9rique_du_temps&oldid=47652746" target="_blank">http://fr.wikipedia.org/w/index.php?title=Pr%C3%A9vision_num%C3%A9rique_du_temps&oldid=47652746</a>.<br>
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