Winter weather terms, breakdown of watches & warnings

Winter weather terms, breakdown of watches & warnings
File photo - Snow covered roads (WBNS-10TV)
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The National Weather Service (NWS) is responsible for issuing winter storm warnings, watches and advisories to alert the public when dangerous winter conditions are expected.

Basic Key Winter Terms:

Freezing Rain - Rain that freezes when it hits the ground, creating a coating of ice on roads, walkways, trees and power lines.

Sleet - Rain that turns to ice pellets before reaching the ground. Sleet also causes moisture on roads to freeze and become slippery.

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Snow Squall - An intense fall of accumulating snow, reducing visibility significantly and often accompanied by increased winds.

Wind Chill - A measure of how cold people feel due to the combined effect of wind and cold temperatures. The wind chill index is based on the rate of heat loss from exposed skin. Both cold temperatures and wind remove heat from the body; as the wind speed increases during cold conditions, a body loses heat more quickly. Eventually, the internal body temperature also falls and hypothermia can develop. Animals can also feel the effects of wind chill.

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Winter Storm Warnings: Take Action!

Blizzard Warnings are issued for frequent gusts greater than or equal to 35 mph accompanied by falling and/or blowing snow, frequently reducing visibility to less than a quarter mile for three hours or more. A Blizzard Warning means severe winter weather conditions are expected or occurring. Falling and blowing snow with strong winds and poor visibilities are likely, leading to whiteout conditions making travel extremely difficult. Do not travel. If you must travel, have a winter survival kit with you. If you get stranded, stay with your vehicle and wait for help to arrive.

Winter Storm Warnings are issued for a significant winter weather event including snow, ice, sleet or blowing snow or a combination of these hazards. Travel will become difficult or impossible in some situations. Delay your travel plans until conditions improve.

Ice Storm Warnings are usually issued for ice accumulation of around 1/4 inch or more. This amount of ice accumulation will make travel dangerous or impossible and likely lead to snapped power lines and falling tree branches. Travel is strongly discouraged.

Wind Chill Warnings are issued for a combination of very cold air and strong winds that will create dangerously low wind chill values. This level of wind chill will result in frostbite and lead to hypothermia if precautions are not taken. Avoid going outdoors and wear warm protective clothing if you must venture outside.

Snow Squall Warnings (SQWs) are issued to protect lives and property. Weather Forecast Office forecasters issue SQWs to provide the public with advance notice of intense, but limited duration, periods of moderate to heavy snowfall, accompanied by gusty surface winds resulting in reduced visibilities and whiteout conditions.

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Watches: Be Prepared

Winter Storm Watches are issued when conditions are favorable for a significant winter storm event (heavy sleet, heavy snow, ice storm, heavy snow and blowing snow or a combination of events.)

Wind Chill Watches are issued when there is the potential for a combination of extremely cold air and strong winds to create dangerously low wind chill values.

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Advisories: Be Aware

Winter Weather Advisories are issued when snow, blowing snow, ice, sleet, or a combination of these wintry elements is expected but conditions should not be hazardous enough to meet warning criteria. Be prepared for winter driving conditions and possible travel difficulties. Use caution when driving.

Wind Chill Advisories are issued when low wind chill temperatures are expected but will not reach local warning criteria. Extremely cold air and strong winds will combine to generate low wind chill readings. If you must venture outdoors, take precautions against frostbite and hypothermia.

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Winter Product Criteria

Winter Storm Watch/Warning - 6 inches of snow or 1/2 inch of sleet in 12 hours; 8 inches of snow in 24 hours; 4 inches of snow or 1/2 inch of sleet in 12 hours; or 6 inches of snow in 24 hours

Winter Weather Advisory - 3 inches of snow or under 1/2 inch of sleet in 12 hours; falling and/or blowing snow reducing visibility to 1/4 mile or less, with winds of 34 mph or less; significant black ice conditions with 2 inches of snow or under 1/2 inch of sleet in 12 hours; falling and/or blowing snow reducing visibility to 1/4 mile or less, with winds of 34 mph or less; significant black ice conditions

Ice Storm Warning - Ice accumulation of 1/4 inch or greater in 24 hours

Freezing Rain Advisory - Ice accumulation of under 1/4 inch

Wind Chill Watch/Warning - Wind chill of -25˚F or less with wind of 10 mph or greater

Wind Chill Advisory - Wind chill of -10˚F to -24˚F with wind of 10 mph or greater

*Information provided by NOAA and the National Weather Service