Weather Advisory: Terms and Definitions

When the threat of winter weather hits, the National Weather Service will issue various advisories and warnings to notify the public of risk levels. Since we live in a region that doesn’t experience consistent winter storms, I wanted to pass along the official definitions and explanations of these notifications for your review. In the case a storm does hit this year, I hope these summaries are helpful in preparing your family for the extreme winter conditions.All information below is taken directly from the National Weather Service. If you have a moment, I also suggest taking a look at my previous blog post, Cold Weather Home Prep, for simple tips on how to keep your home safe and warm this winter.Winter Weather 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. 

• Blizzard Watches are issued when there is a potential for falling and/or blowing snow with strong winds and extremely poor visibility. This can lead to whiteout conditions and make travel very dangerous.  

  
  
  
  

Winter Weather 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.

• Freezing Rain Advisories are issued when light ice accumulation (freezing rain and/or freezing drizzle) is expected but will not reach warning criteria. Expect a glaze on roads resulting in hazardous travel. Slow down and use caution while driving because even trace amounts of ice on roads can be dangerous.

• 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. 

  
  
  
  

Winter Weather Warnings: Take Action!

• 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 Warning 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. 

• 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 1/4 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 visibility 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.

  
  

Key winter weather 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.

• 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 also feel the effects of wind chill; but inanimate objects, such as vehicles and buildings, do not. They will only cool to the actual air temperature, although much faster during windy conditions.