Why Were the Snow Forecasts So Challenging During the Past Week?

This has been a hard week for meteorologists, with multiple threats of cold and snow.  Some aspects of the forecasts worked out, some did not.    For example, Seattle Public Schools cancelled classes, but the predicted snow did not show up.   I have gotten a number of emails asking:  why were the snow forecasts so good last February, but not so good this time around?

> January 6 and > January 7 if you need proof. The mountains did get massive snow, it did get colder, and the lowlands would get some snow.

>my blog discussing the situation.    To illustrate, here is the ensemble of many model snow forecasts for that period for a location in Seattle (North Seattle near Magnusson Park).  HUGE variation in forecasts from very little to six inches.  Uncertainty was large.  We need to communicate this better.

And the fact that the high-resolution  models started backing off for Seattle snow after 6 PM was another sign of non-event over the city.  What Seattle Schools and others should have done was to hold on their decision to close the schools (or other events) until later in the evening, perhaps starting with a few hour delay.    The University of Washington waited to decide and keep the university going the next day.    Dealing with such uncertainty and securing the latest forecasts is one reason we created SnowWatch for city of Seattle.  I hope others will use it.

Lowland snow forecasting is always challenging in our region, since it involves the unusual occurrence of cold and precipitation at the same time.  But improving forecast models, coupled with the communication of uncertainty, should help society make better decisions.