Thermal parameters: BL top height / BL depth / BL topvariab / W* / B/S ratio / Convergence / Wind parameters / sfc parameters / clouds parameters
Quick help: Maximum grid-area-averaged extensive upward or downward air motion within the BL as created by horizontal wind convergence or divergence. Positive value is associated with regional upward convergence area. However, the actual size of such features is usually smaller than can be resolved by the model so only stronger ones will be forecast and their predictions are subject to much error. If CAPE is also large, thunderstorms can be triggered in these areas. Negative value (divergence) produces subsiding (downward) vertical air motion, creating low-level inversions which limit thermalling heights in this area.
Aide rapide: Carte des zones de soulèvement (valeurs positives, favorables aux thermiques) ou d'affaissement (subsidence, valeurs négatives, "stabilisant" l'atmosphère) d'air dus respectivement à la convergence ou la divergence des brises régionales. Ces zones sont difficilement mises en évidence à cause de la résolution médiocre des modèles. Leur prédicition n'est donc pas toujours fiable. Lorsque le paramètre CAPE est grand, les zones de convergence tendent à devenir les zones de déclenchement des orages.