What is a Winter Storm Warning
A winter storm warning is issued by the National Weather Service when dangerous winter weather is expected to arrive very soon or is already happening. When a warning is in effect, people should stop unnecessary travel immediately and get to safety. Warnings are the most serious type of winter weather alert because the threat is immediate and significant.
What is a Winter Storm Watch
A winter storm watch is issued when meteorologists believe dangerous winter weather conditions are likely to occur within the next 12 to 48 hours. A watch means the conditions are possible but not certain, so people have more time to prepare. During a watch, you should gather supplies, plan your route, and get ready in case the storm arrives.
Key Differences
The main difference is timing and urgency. A watch gives you advance warning to prepare, while a warning means the danger is almost here or already happening. Watches typically cover a larger area, while warnings are more specific. When a watch is issued, conditions are still developing and may change. When a warning is issued, meteorologists are confident the storm will bring hazardous conditions.
What Triggers These Alerts
Winter storm warnings and watches are issued for heavy snow, significant ice accumulation, blizzard conditions, or dangerous wind chills. The specific requirements vary by region based on what is typical for that area. For example, 6 inches of snow might trigger an alert in the South but not in the North where heavy snow is more common.
What You Should Do
If a winter storm watch is issued, prepare by stocking food, water, and medicine, charging devices, and checking your heating system. If a winter storm warning is issued, stay indoors and avoid travel unless it is an emergency. During a warning, check on neighbors and family members, and never drive on snow or ice-covered roads. 
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