One of the more difficult forecasts to make is the winter precipitation forecast. The complexity is with determining precipitation type, areal coverage, and whether any winter precipitation will occur in the first place. The public is very sensitive to winter forecasts primarily due to the travel headaches they cause. The winter precipitation forecast is difficult in the "transition zone" region. The rain/sleet/mix/rain line has the ultimate impact in determining which locations will receive winter precipitation and how much. A winter weather situation requires much more time looking at the analysis and model charts than on a typical day. The following questions need to be addressed in a winter precipitation event: What will be the precipitation type? What will be the accumulation? How intense and at what duration will the precipitation be? Is the NWS overdoing or underdoing the event? Will the temperatures be cold enough to support accumulations? What evidence is there that winter precipitation will occur at all? There are three categories for a winter precipitation event. They are:
(1) no event
(2) the no big deal event
(3) the big event
It is up to the broadcast meteorologist to determine which category the event will entail. Calling for a no event when "decent" winter precipitation occurs or calling for a big event and having nothing happen are clearly busted forecasts. Whether an event is big or not is regional dependent. 3 inches of snow in South Bend, Indiana is a no big deal event and is only casually noticed while 3 inches of snow in Atlanta, GA will be a huge event making front cover news and people frantically buying groceries and preparing late into the night the day before the big snowfall. It is up to the broadcast meteorologist to determine what accumulation entails a big event.
Generally, freezing rain on a below-freezing road surface is a big event even in small amount because it can cause traffic accidents with only minor accumulations. Sleet is a big deal if it accumulates sufficiently on the road. Snow is extremely regionally dependent. The northern U.S. generally needs 6 or more inches to be a big deal while anything over an inch in the South is a cause to "panic". After the meteorologist has determined the expected winter precipitation and whether it will be a big deal or not, it is up to the meteorologist to inform the public of how much preparation they should give to the event.
The ultimate embarrassment is to forecast a non-event and a big event occurs or vice-versa. It is common for some broadcast meteorologists to blindly go along with someone else's forecast. This is not a wise habit and will not make one a better forecaster. It is critical the broadcast meteorologist successfully predict the winter precipitation situation as a no event, a no big deal event, or a big event.