Winter Weather Preparedness Week in Colorado - Day 3
Winter Weather Definitions
...WHAT DOES THAT WARNING MEAN ?...
Winter is just around the corner. When a warning is issued will you know what it means...and will you know how to respond. During this Colorado Winter Weather Preparedness Week...please become familiar with our list of potentially life-saving winter weather products.
This list contains the warning and advisory criteria for Colorado west of the continental divide. Criteria east of the divide will be provided today in a separate issuance by the Boulder forecast office.
A HAZARDOUS WEATHER OUTLOOK is issued daily by each National Weather Service office in Colorado. The outlook provides information on potentially hazardous weather out to 7 days into the future. Also... THE WEATHER STORY...a graphic of expected hazardous weather is posted daily on National Weather Service web sites serving Colorado.
WATCHES AND WARNINGS
A WINTER STORM WATCH is issued when hazardous winter storm conditions are possible within the next 3 to 4 days, but the timing, intensity, or occurrence may still be uncertain.
In contrast...winter weather WARNINGS are issued when potentially life-threatening winter weather events are likely to occur.
A WINTER STORM WARNING is issued for the occurrence of heavy snow or any combination of heavy snow and other events. Other events include such things as blowing snow or very cold wind chill temperatures.
WARNING CRITERIA for HEAVY SNOW is defined by the following amounts.
IN THE MOUNTAINS...12 inches or more per storm event.
AT LOWER ELEVATIONS...6 inches or more per storm event.
Or an early season or late season snowfall not meeting the above criteria.
A BLIZZARD WARNING is issued when the following conditions are expected to occur for at least 3 hours:
Sustained winds of 35 mph or greater...
and considerable falling and/or drifting snow
with visibilities frequently less than 1/4 mile.
A HIGH WIND WARNING is issued for the following conditions:
MOUNTAINS...sustained winds of 50 mph or more for at least 1 hour
...or gusts of at least 75 mph for any duration.
LOWER ELEVATIONS...sustained winds of 40 mph or more for
at least 1 hour
...or gusts of at least 58 mph for any duration.
A WIND CHILL WARNING will be issued for the following wind chill temperatures...when combined with sustained winds of at least 10 mph.
MOUNTAINS...minus 35 degrees Fahrenheit or colder
LOWER ELEVATIONS...minus 25 degrees Fahrenheit or colder
A DUST STORM WARNING will be issued for the following conditions:
Visibility reduced to 1/4 mile or less in blowing dust...and sustained winds of 25 mph or greater for at least one hour.
Advisories for winter weather are issued for potentially hazardous conditions.
ADVISORY CRITERIA for SNOWFALL is defined by the following amounts:
MOUNTAINS...5 to 12 inches per storm event
LOWER ELEVATIONS...3 to 6 inches per storm event
A WIND CHILL ADVISORY is issued when wind chills at lower elevations are expected to be between 15 below and 24 below zero...and in the mountains for wind chills between 25 below and 34 below zero.
A DENSE FOG ADVISORY is issued for fog reducing visibilities to 1/4 mile or less.
Additional public information statements will be issued throughout the remainder of this week to help you know how to respond when hazardous winter weather threatens.