The National Weather Service (NWS) issues various alerts to communicate the risk of severe weather events. Understanding these terms is important for personal safety and preparedness, especially during the winter season. These alerts provide time to prepare for potential hazards like heavy snow, ice, or dangerous winds. The NWS uses a tiered Watch, Warning, and Advisory system to communicate the severity and timing of upcoming weather.
Defining the Winter Storm Watch
A Winter Storm Watch is an official NWS notification indicating that conditions are favorable for a significant winter storm event. This alert signals the possibility of severe weather, such as heavy snow, freezing rain, or sleet, over a specific area. The key element of a Watch is the uncertainty surrounding the precise timing, location, or severity of the impending storm.
The NWS typically issues a Winter Storm Watch when hazardous weather is possible within the next 24 to 48 hours. This provides a window for preparation before the event becomes imminent. A Watch is triggered by the potential for specific accumulation thresholds, such as heavy snow or enough ice to damage trees or power lines. While not a guarantee, the Watch confirms that the risk has increased significantly.
Understanding Alert Levels: Watch, Warning, and Advisory
The National Weather Service uses three distinct alert levels—Watch, Warning, and Advisory—to communicate escalating severity and certainty. The Winter Storm Watch is the first level, signifying that dangerous winter weather is possible and provides time to prepare. This alert encourages the public to monitor the situation closely.
When a Watch is upgraded, it typically becomes either a Warning or an Advisory. A Winter Storm Warning is the highest level of alert, meaning that severe winter weather is either imminent or already occurring. Warnings are issued when forecasters are highly confident that conditions will pose a threat to life or property, making travel difficult or impossible. For example, a Warning is often issued when heavy snow accumulation, such as six inches in twelve hours or eight inches in twenty-four hours, is highly likely.
The Winter Weather Advisory is issued when wintry conditions are expected to cause significant inconvenience or impact travel, but are not severe enough to meet Warning criteria. An Advisory indicates that conditions, such as smaller amounts of snow or freezing rain, could be hazardous if caution is not exercised. Unlike a Warning, which calls for immediate action, an Advisory encourages careful behavior.
Immediate Steps to Take During a Watch
The time a Winter Storm Watch is in effect is specifically for preparation, not for reacting to an active storm. Individuals should immediately monitor local forecasts and official NWS updates, as the Watch may soon be upgraded to a Warning or an Advisory. This is the window to secure outdoor property, including loose items like trash cans, patio furniture, and decorations.
Preparation should focus on having necessary supplies for a potential multi-day disruption, especially if power outages are possible. It is helpful to check emergency kits to ensure they contain non-perishable food, bottled water, blankets, flashlights, and a battery-powered radio. Vehicle owners should ensure their gas tanks are at least half-full to avoid fuel line freezing if stranded. Additionally, charge all electronic devices, including phones and laptops, before the storm arrives.