A Wind Advisory is a public notification issued by the National Weather Service (NWS) to inform people of hazardous conditions that do not meet the more severe criteria of a Wind Warning. This alert signifies that high winds are expected to cause inconvenience or potentially threaten life or property if caution is not exercised.
The Specific Wind Speed Criteria
The National Weather Service issues a Wind Advisory when specific sustained wind speeds or wind gusts are forecast to occur over land. Generally, this alert is triggered when sustained, non-thunderstorm winds are expected to reach a speed of 31 to 39 miles per hour (mph) for an hour or more. A Wind Advisory can also be issued if wind gusts are forecast to reach between 46 and 57 mph, even if the sustained wind speed remains lower than the advisory threshold.
Sustained winds refer to the average speed over a short period, typically two minutes, and are the primary factor in determining prolonged stress on structures. Gusts are brief, sudden increases in wind speed that represent the maximum instantaneous wind speed. Gusts are often responsible for immediate hazards, such as snapping tree limbs or overturning high-profile vehicles.
Differentiating Advisories, Watches, and Warnings
The National Weather Service utilizes a three-tiered system—Watch, Advisory, and Warning—to communicate the severity and timing of hazardous weather events. A Watch is the least urgent of the three, indicating that conditions are favorable for a hazardous weather event to occur, often with a lead time of 36 to 48 hours. The purpose of a Watch is to provide ample time for preparation while the occurrence, location, or timing of the event is still uncertain.
An Advisory is issued when a hazardous event is already occurring, is imminent, or is highly likely, but the conditions are less serious than those that would warrant a Warning. Advisories communicate a notable inconvenience or a threat to property if caution is disregarded.
A Warning represents the most serious level of alert, indicating that a hazardous weather event is occurring or is about to occur and poses a threat to life or property. When a Warning is issued, people in the affected area need to take immediate protective action.
Common Impacts and Safety Measures
Winds at the Advisory level are strong enough to create several common hazards, particularly for drivers and property owners. High-profile vehicles, such as vans, trucks, and large trailers, may experience difficulty controlling their steering due to the lateral force of the wind. Drivers should reduce speed and maintain a firm grip on the steering wheel to prevent being pushed out of their lane.
On residential property, advisory-level winds frequently cause minor damage, such as knocking down small tree limbs and scattering unsecured outdoor items. These winds also increase the risk of localized power outages as branches may be blown onto overhead utility lines.
Safety Measures
A primary safety measure during a Wind Advisory is to secure any loose items outside the home to prevent them from blowing away or causing damage. Lightweight objects like trash cans, patio furniture, and trampolines can become dangerous projectiles if they are not properly secured or stored away. People should exercise caution when driving, especially on elevated roadways or bridges where wind is often stronger, and stay clear of trees and utility poles due to the risk of falling debris.