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Glossary

Blizzard Warning - Sustained winds or frequent gusts to 35 miles per hour or greater and considerable amounts of falling or blowing snow (reducing visibility to less than a quarter mile) are expected to prevail for a period of three hours or longer.

Blowing Snow - Typically snow that has already fallen but is now wind-driven. Blowing snow significantly reduces visibility and has the potential to increase the risk of hazards, especially while driving.

Flood & Flash Flood Warning - Issued to inform the public, emergency management and other cooperating agencies that flash flooding (A rapid and extreme flow of high water into a normally dry area, or a rapid water level rise in a stream or creek above a predetermined flood level, beginning within six hours of the causative event) is in progress, imminent or highly likely.

Flood & Flash Flood Watch - Issued to indicate current or developing hydrologic conditions that are favorable for flash flooding (A rapid and extreme flow of high water into a normally dry area, or a rapid water level rise in a stream or creek above a predetermined flood level, beginning within six hours of the causative event) in and close to the watch area, but the occurrence is neither certain or imminent.

Freezing Rain - When rain freezes upon reaching the ground, it is called freezing rain. The freeze that occurs on surfaces following a freezing rain event tends to exponentially increase the amount of weight on the structure. Power outages can occur due to the additional weight from the freezing rain on power lines and trees.

Severe Thunderstorm Warning - This is issued when either a severe thunderstorm is indicated by the WSR-88D radar or a spotter reports a thunderstorm producing hail one inch or larger in diameter and/or winds equal or exceed 58 miles an hour; therefore, people in the affected area should seek safe shelter immediately. Severe thunderstorms can produce tornadoes with little or no advance warning. Lightning frequency is not a criteria for issuing a severe thunderstorm warning. They are usually issued for a duration of one hour. They can be issued without a Severe Thunderstorm Watch being already in effect.

Severe Thunderstorm Watch - This is issued by the National Weather Service when conditions are favorable for the development of severe thunderstorms in and close to the watch area. A severe thunderstorm by definition is a thunderstorm that produces one inch hail or larger in diameter and/or winds equal or exceed 58 miles an hour. The size of the watch can vary depending on the weather situation. They are usually issued for a duration of 4 to 8 hours. They are normally issued well in advance of the actual occurrence of severe weather.

Sleet - Sleet starts out as rain that freezes into ice pellets before it hits the ground. Often times, it will accumulate and lead to hazardous driving conditions.

Snow Squall - Short in duration but great in intensity, snow squalls are snow showers accompanied by strong winds. Visibility is greatly affected during a snow squall.

Tornado Warning - This is issued when a tornado is indicated by the WSR-88D radar or sighted by spotters; therefore, people in the affected area should seek safe shelter immediately. They can be issued without a Tornado Watch being already in effect. They are usually issued for a duration of around 30 minutes.

Tornado Watch - This is issued by the National Weather Service when conditions are favorable for the development of tornadoes in and close to the watch area. Their size can vary depending on the weather situation. They are usually issued for a duration of 4 to 8 hours. They normally are issued well in advance of the actual occurrence of severe weather.

Wind Chill Advisory - Issued when wind chill temperatures pose the risk of becoming hazardous to life after prolonged exposure.

Wind Chill Warning - Issued when the temperature of the air, coupled with the wind speed, becomes hazardous to life.

Winter Storm Warning - This product is issued by the National Weather Service when a winter storm is producing or is forecast to produce heavy snow or significant ice accumulations. The criteria for this warning can vary from place to place.

Winter Storm Watch - This product is issued by the National Weather Service when there is a potential for heavy snow or significant ice accumulations, usually at least 24 to 36 hours in advance. The criteria for this watch can vary from place to place.

Winter Weather Advisory - Winter weather conditions are expected to cause significant inconveniences and may be hazardous.

*Source of portions of definitions - National Oceanic and Atmospheric Administration.

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