Over the years, meteorologists have come up with ingredients methods to
forecast specific weather events, especially winter snowfalls. Such methods
are used along with the numerical guidance models produced by the
These methods apply a cookbook-style ingredients list that
forecasters can use to estimate the precipitation process and apply to the
size and intensity of storms. Fundamentally, this gets to the formation of water
droplets or ice crystals, their structure, abundance, and longevity in the
Such methods are often built on case studies (historically documented)
using the pre- and post-storm data sets. In addition to measured precipitation
amounts these data sets may contain winds, mixing ratios, temperatures, stability
indices and other attributes. This approach truly lets history be our teacher.
A description of ingredients methods can be found here.
I am aware that the National Weather Service in Chanhassen, Minnesota has used the Garcia
Method (Crispin Garcia, 1994) and the Wetzel Ingredients Method (Suzanne Wetzel,
2001) for forecasting precipitation from winter storms. I suspect there are a
number of other methods in use as well.