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‘Cookbook ingredients’ are used to forecast winter weather

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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.