John Hickenlppoer has declared the week of October 21-27th as Winter Weather Preparedness Week. NWS in Boulder has links to many topics that of interest this week such as travel safety, high winds, wind chill, avalanche safety and more. Below is the section for Winter Weather Definitions for Watches, Warnings and Advisories. The full list is available here from the NWS.
Winter Weather Definitions
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.
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.
A BLIZZARD WATCH is issued when blizzard conditions are possible in the next 12 to 36 hours.
- Sustained winds of 35 mph or greater
- considerable falling and/or drifting snow
- with visibilities frequently less than 1/4 mile
A BLIZZARD WARNING is issued in the mountains and foothills for the conditions above, but with winds in excess of 50 mph at the higher elevations.
A HIGH WIND WARNING is issued for the following conditions:
MOUNTAINS and FOOTHILLS
- sustained winds of 50 mph or more for at least 1 hour…or gusts of at least 75 mph for any duration.
- sustained winds of 40 mph or more for at least 1 hour…or gusts of at least 58 mph for any duration.
A HIGH WIND WATCH is issued when high wind conditions are expected to develop in the next 12 to 36 hours.
A WIND CHILL WATCH is issued when wind chill warning criteria are possible in the next 12 to 36 hours.
A DUST STORM WARNING will be issued for the following conditions:
A WINTER WEATHER ADVISORY is issued when:
LOWER ELEVATIONS…3 to 6 inches of snow falls in 12 hours, or 4 to 8 inches in 24 hours
Or when the following conditions are expected:
- When falling snow is accompanied by blowing snow to cause travel problems due to lower visibilities.
- When wind blown snow will occasionally reduce visibilities and create a hazard for travelers.
- For freezing drizzle or a mix of precipitations types, such as snow and sleet, that will impact traavel conditions.
A WIND CHILL ADVISORY is issued whenthe following is expected:
MOUNTAINS…wind chills between 25 below and 34 below zero
LOWER ELEVATIONS…wind chills between 18 below and 24 below zero
A DENSE FOG ADVISORY is issued for fog reducing visibilities to 1/4 mile or less.