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• The vertical structure of winds (m/s) is shown by a wind hodograph that uses one line for each ENS member and one colour for each of a range of levels (warmer colours for low levels and colder ones for upper levels).  Only data from standard pressure levels are shown.  The radial wind speed scale varies to span the value range represented, with certain values (20, 50, 100 m/s) highlighted to aid quick interpretation.  A solid line shows HRES/Ensemble control (which can be compared with, and should be identical to, HRES/Ensemble control winds on the dewpoint depression plot). To avoid plot clutter:
  • the HRES/Ensemble Control run is shown in the same way as the other ENS members.
  • the ENS median is not shown separately.

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Fig8.1.8-4: An example of ENS and HRES winds plotted as hodographs.  Depending on the case, these can be very informative (e.g. the consistency of significant shear among ENS members).  This example shows significant shear from SE'ly winds at low levels to SW'ly winds at mid-tropospheric levels to W'ly winds in the upper troposphere.

CAPE and CIN diagram

The CAPE and CIN diagram shows the distribution of the most unstable Convective Available Potential Energy (CAPE) for three different categories of Convective Inhibition (CIN) in box and whisker format.   

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Fig8.1.8-5: An example of box and whisker plot of the distribution among ENS members of CIN and CAPE.

These diagrams indicate the variation among ENS members of the intensity of convection that may occur (CAPE) together with the likelihood of attaining the release of that convection (i.e. overcoming CIN).  Three arbitrary ranges of CIN are shown: CIN <50J/kg representing a fairly low energy requirement before release of convection,  CIN >200J/kg representing a more substantial energy requirement, and an intermediate value range of CIN.  The vertical scale shows the CAPE energy in J/kg if convection is released.  Box and whisker symbols have their normal meanings.  Black filled circles are shown where there are 5 or fewer ENS members where convection is released.  The numbers of ENS members within each CIN category are given at the top of each column.  The number of members without release of CAPE is shown in the top right hand corner (e.g. CAPE=0: 23 13 meaning 23 13 ENS members failed to identify any CAPE in the forecast ENS ascent).

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