High Impact Weather Summer Course

This “HIW course” is an online course for EUMETCAL and will focus on the use of a particular forecasting method based on Doswell’s ingredient-based forecasting method IBM (1996). This method assumes that three ingredients are needed for convection: moisture, lift, instability (and vertical wind shear to take the modes in convection into account).

These convection modes each have their own distinctive characteristics as regards duration, radar images and, in particular, hazardous weather phenomena (lightning, wind gusts, hail and heavy precipitation). This method has been incorporated into a convection scheme that is currently used at the KNMI forecasting office; it leads, via a few steps, to one of four convection modes. This course e.g. explain the method and describe a number of typically synoptic situations that yield severe convection with some regularity.

The use of the convection prediction scheme in forecasting convection leads to a better physical understanding of convection, more objective forecasting methodologies and more accurate forecasts of hazardous weather phenomena. The convection prediction scheme can be used to make a good assessment of the probability of hazardous weather phenomena. The latter are rare in the case of single cells, for example, whereas pulse storms are frequently accompanied by strong downdrafts (wind gusts) and heavy precipitation and supercells are infamous for their prolonged duration, large hail, strong lightning activity and wind gusts.