DISCUSSION: Winter Storm Warnings are issued when a major snowstorm is EXPECTED imminently within the upcoming 24 hour period for Western Massachusetts. If a Winter Storm Warning is posted, it means that a prior Winter Storm Watch expired and was converted to the Warning, or that a Winter Weather Advisory was upgraded to a Winter Storm Warning. Winter Storm Watches and Warnings both indicate the same kinds of snowstorm impacts, but as opposed to the Watch, the Warning means it’s highly likely that our region will be impacted by strong winter weather.

Furthermore, Winter Storm Warnings can be converted to Blizzard Warnings if blizzard conditions are expected to materialize for at least a 3 hour period. Typically storms of this magnitude take the form of Nor’easters (which typically follow a Miller A or Miller B storm pattern), or Alberta Clippers that slow down and develop just south of Long Island, intensifying rapidly.

DEFINITION: The official definition from NOAA is as follows:

When any of the following is expected within the next 12 to 36 hour:
— Winter weather event having more than one predominant hazard {ie. heavy snow and blowing snow (below blizzard conditions), snow and ice, snow and sleet, sleet and ice, or snow, sleet and ice} meeting or exceeding warning criteria for at least one of the precipitation elements.

Snow, Ocean Effect Snow, or Sleet:
— 6 inches averaged over a forecast zone in a 12 hour period
— 8 inches averaged over a CT, MA, RI forecast zone in a 24 hour period
— 9 inches averaged over a NH forecast zone in a 24 hour period