What Is A Winter Storm?
Updated: Oct 25, 2021
Sometimes it's obvious! Last February had back-to-back major winter storms. However, there are times when it's arguable. 2 inches of snow, 3 inches of snow, a glaze of ice, a coating of sleet, and does it have to impact travel? These are important considerations when winter storm warnings are issued. Also, 3 inches of snow in Louisiana is different than 3 inches of snow in Montana since it snows with more frequency in the north.
All of these factors are considered by each National Weather Service office around the country. In Arkansas, we have 5 offices which issue watches and warnings for our state. They are Little Rock, Tulsa, Memphis, Jackson, and Shreveport. Little Rock is our main office with the others covering the corners of the state.
So what have those offices determined as the official criteria? The maps are below.
Notice the Little Rock office does leave room for adjustments to consider impacts such has road conditions. For instance, 4 inches is a winter storm warning. However, if 3'' falls at 20°, road conditions would be terrible.
When it falls short of all these criteria, a winter weather advisory will be issued. In a few years, the NWS will no longer issue advisories for any weather event. It will likely just go to watches and warnings at that point. It's something I hope the NWS on the national level reconsiders. That's another post for another day.