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What is the difference between a Watch, a Warning, and an Advisory?

The difference between a Watch, a Warning, and an Advisory is pretty simple.

A WATCH means that there is potential for a certain type of weather. For example:

  • Tornado Watch means tornadoes are possible.
  • Winter Storm Watch means that there is potential for a significant amount of snow or ice.

A watch does NOT mean that it is expected. Rather, it means the potential is there, and you should be prepared, and know what you are going to do if severe weather is spotted or a warning is issued.

A WARNING means that life-threatening weather is expected. A warning means you should take action! Using the previous examples:

  • Tornado Warning means that a tornado is expected for your specific location or very close by, and you need to take shelter!
  • Winter Storm Warning means that significant snow or ice is expected, which can be life-threatening to those trapped outside, makes travel difficult/dangerous (at a minimum), impacts your daily routine.

An ADVISORY is like a warning, but not as severe. That is, a threat is expected, but it’s a nuisance rather than life-threatening. For example:

  • Winter Weather Advisory means that a small amount of snow or ice is expected, which will cause travel difficulties and inconveniences. Plan accordingly.

What are the criteria for different watches, warnings and advisories in my area?

Thresholds for what constitutes a watch, warning, or advisory are available on our website here.

Does the National Weather Service send out alerts for hazardous weather?

The National Weather Service sends out alerts for Watches and Warnings over NOAA Weather Radio. Weather radios can be purchased online, as well as at many “big box” and electronics stores. Our warnings also go directly to local media outlets such as radio and TV stations for broadcast.

The National Weather Service does not currently have a smartphone application that alerts you if we issue a warning (although you can set up an icon on your screen that links to the NWS forecast for your area – more info here). However, most newer-model smartphones come preprogrammed to alert for a few of the highest priority warnings issued by various government agencies. From the NWS, those include Tornado Warnings and Flash Flood Warnings. More information on these alerts is available here.

Many private companies make apps that alert NWS warnings for your location on your mobile device, just check your app-store on your mobile device for options.

Also, check with your local/county/city government (typically the emergency management department/agency) to see if they have county/city alerts that you can subscribe to on your mobile device and/or email.

It’s always a good idea to have more than 1 way to receive warnings. Any single way can fail at times.

Where can I get current weather information?

There is a variety of current weather information available. Most of which is linked off our web page.

Our area has many automated surface observing stations maintained by both the National Weather Service and the Federal Aviation Administration. These observations are updated at least each hour and are available in our Hourly Weather Roundup and Regional Weather Roundup. This information is also read over NOAA Weather Radio.

Buoy data for marine areas is available via the National Data Buoy Center.

24-hour temperature and precipitation data for these automated sites is available in our Regional Max/Min Temperature and Precipitation Table, which is issued twice a day. Daily temperature and precipitation data from our Cooperative Observer sites as well as automated hydrologic gauges across our area is available in our Daily Hydrometeorological Data Summary.

Current river level and tidal information as well as forecasts are available via our Advanced Hydrologic Prediction Service page.

Current surface weather maps are available from the Weather Prediction Center’s Surface Analysis page.

Radar and Satellite information are available on our webpage as well.

Finally, data collected by weather balloons is available via the Storm Prediction Center’s Observed Sounding page.

How do I obtain past weather information?

Preliminary local climate data, including temperature, precipitation and snowfall is available on our local climate page.

In the event you need climate data for legal purposes, you will need to purchase a certified copy of finalized data from the National Center for Environmental Information’s website. This website also has more comprehensive data such as wind, pressure, and hourly observations for sites in our area and all across the country. They can also be phoned at 828-271-4800.

How do I get a detailed forecast for an area I’m interested in?

Simply navigate to www.weather.gov/washington or www.weather.gov/baltimore and enter your zip code or city and state in the “Enter location…” box in the upper-left. Alternatively, you can click on your area of interest on the map in the center of the page.

How do I get long range climate forecasts for my area?

Our office handles weather forecasts out to seven days. Beyond that, the Climate Prediction Center (CPC) offers monthly forecasts for overall trends in temperature and precipitation.

What is a computer model?

A computer model is basically a very sophisticated calculator. It calculates a series of equations that govern the movement of air and moisture in the atmosphere forward from the current time to see where things will end up. Although our computer models have become very powerful, there are still computing power limitations that do not allow the models to see very small scale weather features. For this reason, the models must estimate at times. An example of this is that most models can’t see individual thunderstorms rise and fall, so they must estimate how thunderstorms in an area will affect the atmosphere. Each model has a slightly different method of estimation which is why model forecasts have differences, especially in the longer range.

As models continue proliferate and become more sophisticated – running on some of the largest supercomputers in the world – more and more we tend to not look at individual models. We increasingly are looking at ensembles/sets of models, which take dozens of individual models and find what is most likely, what is the worst case, and what is the best case scenario. We then need to convey to the public what we expect to happen, while also conveying the range of possibilities that still exist. This range tends to be large several days out, and then shrinks as an event nears.

Where can I find more information on NOAA Weather Radio?

Information about NOAA Weather Radio and the different frequencies throughout our coverage area are available on our local NOAA Weather Radio page.

How can I become a trained National Weather Service SKYWARN Spotter?

If you would like to join our SKYWARN Spotter program, please visit our SKYWARN page. Training classes are typically offered from the fall through the spring in various locations across our area. Classes are being added all the time, so check back often!