A Great Example of Why Snow Forecasting is Tough

One of our Facebook Fans asked this morning why we had their town at 1 inch of snow for tonight's storm while the NWS had a warning out for 8-14 inches in Newton, Massachusetts. The short answer is that our forecasters believe that much more rain will mix with the snow and keep accumulations way down near the shore on coastal New Hampshire. Here's where the city is located (AccuWeather.com forecast for Friday):

And this is our forecast map from this morning. Although we are predicting over 10 inches inland, we really believe there will be very little snow at the coast.

The National Weather Service's forecast was actually for 3-5", if you read their text forecast. The warning was issued for the "interior" part of the county where over a foot would fall. But their map was even more stark:

So a difference of a couple dozen miles could mean the difference between 10 inches of snow and 1. This is why forecasting winter storms is so difficult. Newer updated forecast models routinely shift storm centers dozens of miles.

Another problem is snow being a factor of 10 (approximately) higher than rain creates an exaggerated problem: Sure, you know the difference between 2 and 6 inches of snow, but do you know the difference between .2 and .6 inches of rain? Most people wouldn't, yet it's the same amount of liquid precipitation falling.