Ordinary-cell convective storms - Severe Convective Storms and Tornadoes: Observations and Dynamics - page 107

(a)

(b)

Figure 3.12. (a) Cloud base in a supercell that has striations like an orographic wave cloud, on
May 29, 2008, north central Kansas. (b) Orographic wave clouds in the lee of the Rockies just
west of Ward, CO on January 2, 2008 (photographs by the author).

1 = 2 ; CAPE(EL) is
usually just referred to as ''CAPE''. High CAPE is favored by relatively cool air
aloft and relatively warm air at low altitude. Stable layers above the LFC act to
reduce CAPE from it would have otherwise been. Stable layers in mid-levels of the
troposphere are typically associated with sinking motion on the synoptic or mesos-
cale. Middle and upper-tropospheric fronts are characterized by stable layers, and
as such act to reduce CAPE. Storm-chasers colloquially describe mid-level stable
layers as ''CAPE robbers'' ( Figure 3.13 ).
When there is a low-level, capping inversion (or stable layer), deep convection
will not be initiated until the ''cap is broken'' (i.e., the LFC is attained through
cooling at cap level via mesoscale lift and/or warming below via surface heating).
Since the cap suppresses convective development everywhere except where it is

Total CAPE is CAPE(EL) and w ð EL Þ¼½ 2 CAPE ð EL Þ