Starting this winter, the National Weather Service will change the phrasing of several of its alerts.
We’re used to wind chill advisories, watches, and warnings; on average, we receive 16 advisories and four warnings per winter. However, as the National Weather Service strives to simplify its threats, they will now be referred to as cold weather advisories, severe cold watches, and warnings.
Cold is cold, whether there’s wind or not! That’s the message the National Weather Service hopes to convey with this modification.
Previously, wind chill notifications were based on apparent temperature and a certain wind threshold. These notifications will now be sent based on either the wind chill or the ambient temperature, with no wind required.
When temperatures or wind chills are expected to be between -30 and -39 degrees, a cold weather alert will be issued. When temperatures or wind chills are expected to be -40 degrees or lower, an extreme cold watch will be issued several days in advance, followed by an extreme cold warning as the dangerously cold temperatures approach.
For example, a cold weather advisory would be issued if the temperature was -5 degrees and the wind was 25 miles per hour, or if the temperature was -15 degrees and the wind was only 10 miles per hour, as wind chills would be in the 30s below zero.
With the new adjustments, even if the wind is expected to be calm, maybe due to Arctic high pressure overhead, a cold weather advisory and an extreme cold warning may be issued if the actual air temperature falls below the thresholds.
Some of this vocabulary may be familiar to you from an experiment conducted with them in 2011-2012, as well as a survey completed by some Burleigh County residents. The majority of respondents reported hearing both the extreme cold and wind chill warnings, which induced preventive measures.
This allowed the NWS the confidence to implement the modifications right away, helping to emphasize that the cold is dangerous regardless of whether there is wind.
Beginning this winter, cold and snow alerts will occasionally overlap, rather than merely citing the extreme cold in the snow headline. This is to make people aware of extremely low temperatures even during winter storms.
Reference:
Wind chill alerts to get new names this winter from National Weather Service | Morse Code of Weather