Watch vs. warning: Differences explained

A weather watch is issued when the conditions are right for a specific type of hazardous weather event to happen, explains the College of DuPage. It indicates that there is a risk of dangerous weather in the immediate future but the location and timing are unknown, adds Chesterfield Fire. Most weather alerts in the U.S. are issued by the National Weather Service (NWS) in conjunction with local officials.

When you see a weather watch in place, you should have a plan of action in case the situation worsens. You should also pay close attention to the news for updates and if it progresses into a weather warning. Weather watches can cover a large area.

A weather warning is issued when a weather event is imminent or already occurring. Warnings indicate a serious threat to life and property. If you see a warning in your area, you should take immediate steps to get to safety, advises the National Weather Service (NWS). Warnings tend to cover smaller areas than weather watches.

What is a weather advisory?

Weather advisories are similar in that they are issued when a weather event is about to happen or has happened. The difference is the severity of what they communicate. Advisories are issued for less severe weather but caution should still be taken as a lack of caution can lead to life or property-threatening conditions.

The main differences between a watch and a warning are in the timing, certainty, and severity of the weather event, explains Chesterfield Fire.

Timing

Watches are typically issued well in advance (usually at least 24 hours), while warnings are issued when severe weather is imminent or already occurring.

Certainty

Watches indicate that conditions are favorable for severe weather, with at least a 50% chance of occurrence. On the other hand, warnings are issued when there is at least an 80% probability of the event happening.

Area covered

Watches usually cover larger areas, while warnings are more localized around where the weather event is most likely to occur, explains the National Weather Service.

A weather warning is more severe than a weather watch. Warnings indicate that there is a high potential for severe weather. Warnings also indicate that this severe weather will be capable of causing severe harm to people and property. If it’s a weather warning, you should take immediate steps to get to safety according to your local authorities’ directions.

If your area is under a weather watch, you should be careful and stay vigilant for changes in the notice.

While the National Weather Service provides standardized definitions for classifying weather events, the specific criteria for issuing these alerts may vary based on the region and the local conditions. For specific information about your area’s thresholds for weather alerts, you should consult your local forecast office.

The National Weather Service (NWS) is part of the United States’ meteorological infrastructure. They are responsible for providing weather forecasts, warnings, and alerts to help protect people and property from hazardous weather.

They keep an eye on the weather nationwide and provide people with information about what kind of weather they will be encountering. They also play a key role in defining the specifics of severe weather events and when to issue these alerts.

When your area is experiencing a hazardous weather event it is imperative to understand what these alerts mean and how you should react as a result of the alert issued. In this section, we will discuss many of the common weather alerts and the steps you can take to keep yourself safe.

Severe thunderstorms

A severe thunderstorm is officially defined as a storm that can produce hail that is an inch or larger, or gusts of wind over 58 mph, according to the NWS. Winds from these storms are strong enough to cause damage to trees.

If a storm watch is issued in your area, you should be vigilant, advises the NWS. Tune in to your local forecast so you can understand the status of the storm and if it will escalate into a storm warning. If you have plans outside the home, consider canceling them.

In the event of a storm warning, you should get inside away from doors and windows. You should avoid open rooms such as cafeterias and gymnasiums, advises the NWS. If you are in a car, do not get out if it is unsafe to do so. If you are able, drive to a better shelter.

Tornados

A tornado is a rapidly spinning column of air that stretches from a thunderstorm down to the ground, explains the NWS. Tornadoes can cause catastrophic damage and are extremely dangerous.

During a tornado watch, conditions are favorable for tornadoes to form. Stay informed about the weather and be prepared to take shelter if necessary. If a tornado warning is issued, a tornado has been sighted or indicated by weather radar. Immediately take shelter in a basement or an interior room on the lowest floor of a sturdy building.

If you're in a mobile home or vehicle, get to the nearest sturdy shelter immediately. These structures are particularly vulnerable to high winds and may even be moved from their place.

Flooding

Flooding occurs when water overflows onto normally dry land, says the NWS. It can happen gradually or suddenly, posing significant risks to life and property. A flood watch means flooding is possible in your area. Stay alert, monitor weather reports, and be prepared to move to higher ground if necessary.

During a flood warning, flooding is imminent or already occurring. Move to higher ground immediately and avoid walking or driving through flood waters. This advice is applicable in the event of a flash flood but you may have less time to react.

Excessive heat

Extreme heat can be dangerous, especially for vulnerable populations like the elderly, young children, and those with chronic health conditions, the NWS explains. It leads to hundreds of deaths in the U.S. each year. A heat advisory is issued when the combination of heat and humidity is expected to make it feel like it is 95 to 99 degrees for two or more consecutive days.

Stay hydrated, limit outdoor activities, and check on vulnerable neighbors. An excessive heat warning is issued when the heat index is expected to be 100 degrees or higher for at least two hours. Take extra precautions, find air conditioning, and avoid strenuous activities.

Eat light, easy-to-digest foods like fruit and salad and pay careful attention to the potential for food spoilage. Use fans to direct hot air away from rooms or draw cooler air in.

A heat warning may also be called a heat advisory depending on your region and a watch may be called an excessive heat outlook.

Winter storm warning

A winter storm warning indicates that heavy snow, sleet, or freezing rain is expected, according to the NWS. Snow accumulation of 6 inches or more in 12 hours, or 8 inches or more in 24 hours, is forecasted.

During a winter storm warning, stay indoors if possible. If you must go outside, wear layers of warm clothing and do what you can to stay warm. Prepare for power outages and avoid travel unless absolutely necessary.

Freeze warning

A freeze warning is issued when sub-freezing temperatures are expected for at least two consecutive hours, the NWS explains. These conditions can be harmful to sensitive vegetation and outdoor plumbing.

During a freeze warning, protect sensitive plants by covering them or bringing them indoors. Allow indoor faucets to drip and open cabinet doors to allow warmer air to circulate around pipes.

In extreme cold your main goal is to stay warm. Drinking hot beverages such as cocoa, tea, or coffee can help. You should limit or eliminate any time spent outdoors. If you must go outside, minimize the amount of skin exposed to the elements. Wear layers and pay close attention to covering your extremities.

Red flag warning

A red flag warning is issued when critical fire weather conditions are occurring or will occur shortly, states the NWS. This combination of strong winds, low relative humidity, and warm temperatures can contribute to extreme fire behavior.

If your area is observing a red flag warning, avoid activities that could spark fires. Follow all local fire restrictions and guidelines. Do not throw cigarettes or matches out of moving vehicles. Ensure that you extinguish all outdoor fires properly. Be prepared to evacuate if necessary.

Extreme fire behavior is the more serious fire alert. This implies that a wildfire is most likely going to go out of control. The National Wildfire Coordinating Group (NWCG) calls out some of the indicators, which include:

• Relative humidity is below 15%
• A transition from a surface fire to a crown fire
• Increased spotting
• Fire whirls

High wind warning

High wind warnings are issued when sustained winds of 40 mph or higher or gusts of 58 mph or higher are expected for at least one hour, claims the NWS. During a high wind warning, secure loose outdoor objects and avoid being outside in forested areas or around trees. If driving, keep both hands on the wheel and slow down, especially if operating a high-profile vehicle.

Tsunami

Tsunami notices are issued by the National Tsunami Warning Center to notify local officials about the potential for a tsunami to form. The designations for tsunami alerts are a bit different than for the other types of weather we’ve discussed so far.

A tsunami information statement indicates that an earthquake has occurred but there is no threat or it is very distant. These types of alerts typically do not escalate beyond this point.

Tsunami watches indicate that an earthquake happened in the distance and a tsunami is possible but not imminent. At this stage, people in the danger zone should be prepared to take action if the situation evolves.

A tsunami advisory means that a tsunami with the potential for strong waves or currents dangerous to those in or very close to the waters expected or in progress. You should stay out of water and move away from beaches or any other waterways.

The highest threat level is a tsunami warning. These communicate serious danger. A tsunami that may cause widespread flooding is imminent and may last hours or days. In these cases, it is vital to listen to the directions of your local authorities. In most cases evacuation to higher ground or inland is recommended.

Preparation for hazardous weather begins before a watch or warning has been issued. Here are some steps you can take to help you be prepared for a weather alert.

Be aware of the weather conditions in your area

The first step is to understand your risks. Are you in an area with harsh winters? Is your home below sea level? These factors can help you understand what kind of weather you are most vulnerable to. Start by checking your Local Weather Forecast Office on the National Weather Service site.

Create an emergency plan

Develop a comprehensive emergency plan for your household or business. Live Green Howard recommends your plan should include:

• Designated meeting places both near your home and outside your neighborhood
• Emergency contact information for family members and local authorities
• Evacuation routes and shelter locations
• Specific roles and responsibilities for each family member or employee

Assemble an emergency kit

Put together an emergency supply kit containing essential items:

• Non-perishable food and water (at least a three-day supply)
• Flashlights and extra batteries
• First aid kit and necessary medications
• Battery-powered or hand-crank NOAA weather radio
• Important documents in a waterproof container
• Cash

Secure your home

Take steps to protect your home or business:

• Trim trees and remove dead branches that could fall during a storm
• Secure or bring inside outdoor furniture, decorations, and other loose items
• Consider installing storm shutters or having plywood on hand to cover windows
• Ensure your roof and gutters are in good condition
• Understand what perils are covered by your home insurance (for example, a standard policy usually doesn’t cover flooding)

Prepare your car

Keep your vehicle ready for emergencies:

• Maintain a full tank of gas
• Store an emergency kit in your car
• Know alternative evacuation routes
• Consider comprehensive coverage to keep your car protected

Practice your plan

Regularly review and practice your emergency plan:

• Conduct drills for different scenarios (e.g., sheltering in place, evacuating)
• Ensure everyone knows how to shut off utilities if necessary
• Update your plan and kit annually or as circumstances change

By following these preparedness steps, you'll be better equipped to handle hazardous weather situations. Remember, being proactive and staying informed are key to weathering any storm safely.