DISCUSSION: Winter Weather Advisories are posted by NOAA for Western Massachusetts when a light to moderate snow event is expected, or when enough potential exists for snow and ice that negative impacts are expected. The purpose of the advisory is to alert the public that they can expect somewhat hazardous travel conditions. Still, these are not major winter weather events, but they can cause slippery driving conditions, and problems with foot or bike travel. Such storms typically do not cause air travel disruptions.

DEFINITION: The official definition from NOAA is when any of the following is expected within the next 12 to 24 hours:

1. Winter weather event having more than one predominant hazard (i.e. snow and ice, snow and sleet, or snow, ice & sleet) meeting or exceeding advisory criteria for at least one of the precipitation elements, but remaining below warning criteria.

Snow, Ocean Effect Snow, and/or Sleet:
— 3 inches averaged over a CT, MA, RI forecast zone in 12 hours
— 4 inches averaged over a NH forecast zone in 12 hours

2. Snow and Blowing Snow
Sustained or frequent gusts of 25 to 34 mph accompanied by falling and blowing snow occasionally reducing visibility to less than a 1/4 mi for greater than 3 hours

3. Blowing Snow
Widespread or localized blowing snow reducing visibility to less than a ¼ mi with winds less than 35 mph

4. Black Ice
A Special Weather Statement for black ice will usually be issued when sufficient moisture is expected to cause a thin layer of ice on road surfaces, typically on cloudless nights. At forecaster discretion a formal Winter Weather Advisory may be issued instead.