Ordinary-cell convective storms - Severe Convective Storms and Tornadoes: Observations and Dynamics - page 140

(a)
AIRFOIL
(b)
Figure 3.39. (a) Illustration of how air flowing up and over a cold pool behaves like air flowing
up and over an airfoil. (Top) Vertical cross section showing airflow (streamline) relative to an
airfoil shaped like a cold pool wedge; a dynamic high-pressure area slows the air down as it
encounters the airfoil (in the reference frame of the moving airfoil) and is lifted upward.
(Bottom) Shelf (or arcus) cloud produced as stable air is lifted to saturation at the leading
edge of a gust front (advancing cold pool), early in the morning of May 27, 1977, in Norman,
OK (photograph by the author). (b) Underside of air flowing up and over a cold pool: the
''Whale's Mouth'' in north central Oklahoma on May 15, 2009. The underside is ragged and
looks turbulent, as there is mixing at the interface between the cool air below and the warmer
air aloft (photograph by the author).