What is the difference between a winter weather watch, warning and advisory?
It has to do with timing, precipitation amounts and uncertainty.
In addition precipitation amounts vary by locale. For example in Syracuse NY more snow is required to activate these alerts compared to locations farther to the south.The criteria quoted below are from the National Weather Service in Binghamton (BGM) and the apply to most of New York state, including all of ski country.
A Winter Weather Outlook details weather that may cause significant impact in the next 3 to 7 day. It is likely to eventually lead to the issuance of a Winter Weather Watch or Warning. A more precise scientific discussion on the event can also be found in the Area Forecast Discussion. Forecasts in the day 3 to 7 time day range often have a lot of forecast uncertainty. Generally there is a 30 to 50% chance that the event will occur and reach warning criteria. The Winter Weather Outlook is intended to provide information to those who need considerable lead time to prepare for the event.
A Winter Weather Watch is generally issued 24 to 72 hours in advance when the risk of the event has increased to a 50 to 80% certainty that warning thresholds will be met. It is intended to provide enough lead time so those who need to set their plans in motion can do so. When a watch is issued a message will appear as a headline in text products including the zone forecast. It will change the color to purple of the affected counties on the NWS front page map.
A Winter Storm Warning is issued when a hazardous winter weather event is occurring, is imminent, or has a very high probability of occurrence — generally greater than 80%. A warning is used for conditions posing a threat to life or property. When a warning is issued a message will appear as a headline in text products including the zone forecast. It will change the color of the affected counties to pink on the NWS front page map.
A Winter Weather Advisory is issued when a hazardous winter weather event is occurring, is imminent, or has a very high probability of occurrence — generally greater than 80%. An advisory is for less serious conditions that cause inconvenience and, if caution is not exercised, could lead to situations that may threaten life or property. When a advisory is issued a message will appear as a headline in text products including the zone forecast. It will change the color of the affected counties to slate blue on the NWS front page map.
Source: National Weather Service (BGM)