3/29/11 Initiation Questions

[cwachal]

Question:

You say the cap will be hard to break but according to the latest meso analysis the cap has broken in 2 places. SW of Houston and on the Mexico side of the Rio Grande river. If this is the case we should see storms fire soon as SBCAPE is already 2500 in those locations with lifted indexies of -5 or lower.

 

[Michael Nicolaou]

Question:

You say the cap will be hard to break but according to the latest meso analysis the cap has broken in 2 places. SW of Houston and on the Mexico side of the Rio Grande river. If this is the case we should see storms fire soon as SBCAPE is already 2500 in those locations with lifted indexies of -5 or lower.

Eagle Pass magic about to happen. Looking at VIS SAT there is considerable erosion of the cloud deck from NW to SE near DRT. Cumulous field building and this area will rapidly heat to help any storm that get's started to break the cap. Looking from some nice non-tornadic supercells later on. Nice pocket of 3k Cape just west of Eagle Pass on latest meso analysis.

 

[cwachal]

What about the area along the gulf coast SW of Houston.. there is pretty good SBCAPE there with no cap either.

 

[Tim Supinie]

Are you using the SPC mesoanalysis to make the statement that the cap is broken? One thing to know about that is that it's generated from a forecast model (the RUC, to be specific), and they don't always handle the computation of CAPE and CINH very well due to their finite vertical grid spacing. Generally, the rule of thumb is that if there aren't any thunderstorms, the cap hasn't been broken yet. You can get an idea of how close initiation may be by looking at the visible satellite (is there a towering cumulus field?) and surface observation products (where are the convergence zones?).