National Weather Service facts for kids
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| Agency overview | |
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| Formed | February 9, 1870 |
| Preceding agency |
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| Jurisdiction | United States federal government |
| Headquarters | Silver Spring, Maryland 38°59′30″N 77°01′48″W / 38.99167°N 77.03000°W |
| Annual budget | US$1.204 billion (FY 2021) |
| Agency executive |
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| Parent agency | National Oceanic and Atmospheric Administration |
| Child agency |
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| Key document |
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The National Weather Service (NWS) is a special agency of the U.S. government. Its main job is to give weather forecasts and warnings about dangerous weather. They also provide other weather information to help keep people safe and informed.
The NWS is part of the National Oceanic and Atmospheric Administration (NOAA). This group is under the Department of Commerce. The NWS headquarters is in Silver Spring, Maryland. From 1890 to 1970, it was called the United States Weather Bureau.
The NWS does its work through many national and local centers. There are 122 local Weather Forecast Offices (WFOs). Because the NWS is a U.S. government agency, most of its weather information is free for everyone to use.
Contents
- How Did the National Weather Service Start?
- What Kinds of Forecasts Does the NWS Make?
- How Does the NWS Get Weather Data?
- What Are Event-Driven Products?
- How Are Products Shared?
- What Technology Does the NWS Use?
- How Is the NWS Organized?
- Why Were There Attempts to Change the NWS?
- Why Are Forecasts Sometimes Not Perfect?
- See also
- Images for kids
How Did the National Weather Service Start?
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People wanted a government weather service as early as 1844. This was when the electrical telegraph was invented. In 1869, Cleveland Abbe started making weather forecasts. He used daily weather data sent by telegraph.
A man named Increase A. Lapham also worked to create this service. He saw how powerful storms could be in the Great Lakes area. In 1870, the U.S. Weather Bureau was officially created. President Ulysses S. Grant signed the law. Its job was to take weather observations and warn people about storms.
The agency was first part of the War Department. It was assigned to the U.S. Army Signal Service. General Albert J. Myer gave it its first name: The Division of Telegrams and Reports for the Benefit of Commerce. Cleveland Abbe became the first chief meteorologist. He pushed for weather to be studied scientifically.
In 1890, the agency became a civilian group. It moved to the Department of Agriculture. Here, it started giving flood warnings and fire weather forecasts. It also created the first daily national weather maps.
How Did the NWS Grow in the 20th Century?
In 1937, the first Weather Bureau radiosonde was launched. This was a device sent into the sky by a balloon to measure weather. By 1939, they switched to using these instead of aircraft for observations.
For a long time, the Bureau did not use the word "tornado" in public forecasts. They worried it would cause panic. But this also meant people didn't get warnings. In 1938, they started giving tornado warnings only to emergency management teams.
In 1940, the Bureau moved to the Department of Commerce. In 1950, the ban on public tornado alerts was lifted. However, it took until 1952 for the first experimental public tornado forecasts to be issued.
In 1957, the Bureau started using radars. These were used for short-term forecasts of local storms. They used modified Navy aircraft radars to create the WSR-57 system. A network of these radars was put in place across the country.
In 1970, the Weather Bureau changed its name to the National Weather Service. This happened when the National Oceanic and Atmospheric Administration (NOAA) was formed. By the 1980s, the NWS was still using older radar and communication equipment.
Between 1988 and 1997, a new radar system called NEXRAD was put in place. These Doppler radars helped improve the detection and warning time for severe storms.
What Kinds of Forecasts Does the NWS Make?
The NWS creates many different forecasts for people to use. In the past, forecasts were mostly text. Now, the NWS uses more digital maps and images. Each of the 122 Weather Forecast Offices (WFOs) sends their forecasts to a national server. This creates the National Digital Forecast Database (NDFD).
The NDFD collects common weather information. This includes how much rain will fall, temperature, and cloud cover. You can see this data online or download it.
Fire Weather Forecasts
The NWS creates many products about wildfires every day. Local WFOs issue a Fire Weather Forecast daily. This forecast covers up to seven days. It includes important weather details for fire control. For example, it tells about wind direction, speed, and rain. Fire crews use this to plan their work and assess fire danger.
NWS meteorologists also create a special coded forecast for the United States Forest Service. This data goes into a computer model called the National Fire Danger Rating System (NFDRS). This model tells the daily fire danger. It uses five ratings: low, moderate, high, very high, or extreme.
Local WFOs also issue Fire Weather Watches and Red Flag Warnings. These warn people and other agencies about conditions that could cause extreme fires. The NWS Storm Prediction Center also gives fire weather analyses. These help local offices understand critical fire weather conditions. This includes "dry thunderstorms" in the western U.S.. These storms have lightning but no rain because it evaporates before reaching the ground.
Sometimes, forestry officials ask for a "spot forecast" for a specific location. This helps them decide if it's safe to start a prescribed burn. NWS forecasters called Incident Meteorologists (IMETs) also help at large wildfires or other disasters. IMETs are specially trained to work with emergency teams. They set up mobile weather centers at the site. They provide continuous weather support. IMETs use cell phones, laptops, and special equipment to get weather data. They can also use remote weather stations to gather specific data.
Local Weather Forecast Offices
The NWS has 122 local offices called Weather Forecast Offices (WFOs). These offices issue forecasts for specific areas. Each WFO covers several counties or areas. They are responsible for creating and sending out forecasts and weather alerts for their region.
Some products only issued by WFOs include:
- Severe thunderstorm and tornado warnings.
- Flood, flash flood, and winter weather watches and warnings.
- Some aviation weather products.
- Local forecast grids.
You can find the forecasts from a WFO on their individual pages on the Weather.gov website.
National Centers for Environmental Prediction
This group has several centers that provide specialized forecasts.
Aviation Forecasts
The NWS helps the aviation community with special forecasts. Each WFO issues Terminal Aerodrome Forecasts (TAFs) for airports in their area. TAFs are short, coded forecasts for a specific airport. They cover 24 or 30 hours and are issued every six hours. TAFs only include weather important for flying, like wind, visibility, cloud cover, and wind shear.
Twenty-one NWS Center Weather Service Units (CWSU) work with the FAA. They give up-to-the-minute weather information to air traffic controllers. They focus on weather that could be dangerous for planes or slow down air traffic.
The Aviation Weather Center (AWC) in Kansas City, Missouri, also helps pilots. It issues two main products:
- AIRMET (Airmen's Meteorological Information): This gives information about icing, turbulence, and other conditions that affect flight safety.
- SIGMETs (Significant Meteorological Information): These are issued for important weather that might affect an airport or flight path. This includes large areas of thunderstorms or severe turbulence.
Storm Prediction Center
The Storm Prediction Center (SPC) in Norman, Oklahoma, issues severe thunderstorm and tornado watches. They work with local WFOs to define the areas affected. The SPC also tracks reports of severe hail, wind, or tornadoes.
They provide forecasts for severe weather up to eight days in advance. The risk of severe thunderstorms is shown in categories like marginal, slight, enhanced, moderate, or high. The SPC also issues fire weather outlooks. These help local WFOs decide if a Red Flag Warning is needed.
Weather Prediction Center
The Weather Prediction Center in College Park, Maryland, helps forecast future rainfall. They also identify areas where heavy rain is likely. Local NWS offices then issue Flood Watches, Flash Flood Watches, and Flood Warnings for their areas. These warnings depend on the geography, land use, and time of year. For example, a Flood Warning might be issued for an ice jam on a river in winter.
The NWS has improved how it shares flood information with the Advanced Hydrologic Prediction Service (AHPS). This service lets anyone see real-time and forecast data for rivers, lakes, and streams. It also provides long-range flood predictions for planning.
River Forecast Centers
Thirteen River Forecast Centers (RFCs) issue daily river forecasts. They use computer models based on rainfall, soil, and other factors. The first center started in 1946. Some RFCs also forecast seasonal snowpack and peak river flows. Farmers, hydroelectric dam operators, and water supply managers use these forecasts.
Ocean Prediction Center
The National Weather Service Ocean Prediction Center (OPC) in College Park, Maryland, issues forecasts for ocean areas near the United States. NWS centers and WFOs issue several marine products:
- Coastal Waters Forecast (CWF): A text forecast issued by coastal WFOs. It describes expected weather and wave heights for coastal waters.
- Offshore Waters Forecast (OFF): Issued by the OPC for waters further from the coast.
- NAVTEX forecast: A text forecast from the OPC for U.S. Coast Guard broadcasts.
- High Seas Forecast (HSF): A routine text forecast issued every six hours by OPC. It provides warnings and forecasts for sailors on the open ocean.
National Hurricane Center
The National Hurricane Center (NHC) in Miami, Florida, and the Central Pacific Hurricane Center (CPHC) in Honolulu, Hawaii, watch for tropical weather. They monitor the Atlantic and parts of the Pacific Ocean. They issue outlooks and discussions about tropical cyclones (like hurricanes). If a tropical cyclone threatens the U.S., local WFOs issue statements about its expected effects. The NHC and CPHC issue advisories, forecasts, and warnings for these storms.
Climate Prediction Center
The Climate Prediction Center (CPC) in College Park, Maryland, handles all of the NWS's climate forecasts. Their goal is to forecast how short-term climate changes might affect us. They focus on extreme weather events. Their products cover periods from a week to several seasons. Most of their forecasts cover the U.S. and Alaska.
Local Weather Forecast Offices also issue daily and monthly climate reports. These include recorded high and low temperatures and other information. This data is checked by the National Climatic Data Center.
How Does the NWS Get Weather Data?
Surface Observations
The main network of weather stations in the U.S. is the Automated Surface Observing Systems (ASOS). The NWS, FAA, and Department of Defense work together on ASOS. These stations are usually near airport runways. They help with forecasts and aviation. ASOS stations send hourly observations and special reports when conditions change. They measure sky condition, visibility, weather, pressure, temperature, dew point, wind, and rain.
Because ASOS stations are expensive, they are far apart. So, the Cooperative Observer Program (COOP) helps a lot. This program has about 11,000 volunteer weather observers. They provide much of the weather data for the country. The COOP was started in 1890. Its goals are to:
- Provide daily temperature, snowfall, and rainfall data. This helps define the U.S. climate and track long-term changes.
- Provide real-time data to help NWS forecasts and warnings.
The NWS also gets data from private networks like the Citizen Weather Observer Program. They also support the CoCoRaHS volunteer network.
Marine Observations
NWS forecasters need good marine observations. This helps them prepare and check their forecasts. Large bodies of water greatly affect the weather. The NWS's National Data Buoy Center (NDBC) operates about 90 buoys and 60 coastal observing systems (C-MAN). These stations measure wind, pressure, and air temperature. Buoys also measure sea surface temperature and wave height. All stations report hourly.
The United States Voluntary Observing Ship (VOS) program also collects weather data. This program gets weather and ocean data from ships. The U.S. program is the largest, with nearly 1,000 ships. Ship officers take observations and send them to the NWS. This data is then shared for weather forecasting and other uses.
Upper Air Observations
Data from the upper atmosphere is very important for forecasting. The NWS operates 92 radiosonde locations in North America and ten in the Caribbean. A radiosonde is a small instrument package. It hangs below a 2-meter wide balloon filled with hydrogen or helium. These are released daily around 11 AM and 11 PM UTC.
As the radiosonde rises, it measures pressure, temperature, and humidity. It sends this data to a ground receiver. By tracking the radiosonde, scientists also get wind speed and direction high up. The flight can last over two hours. The balloon can go higher than 35 kilometers (21 miles). When the balloon bursts, a small parachute brings the radiosonde down safely.
What Are Event-Driven Products?
The National Weather Service has a system for warning the public about dangerous weather. It has different levels of alerts:
- Outlook: These are issued daily by local Weather Forecast Offices. They talk about possible hazardous weather for the next seven days. This includes thunderstorms, heavy rain, floods, winter weather, and extreme heat or cold. They help emergency teams prepare.
- Advisory: An advisory is issued when a hazardous event is happening or likely. Advisories are for less serious conditions than warnings. They can cause problems and might threaten life or property if people are not careful.
- Watch: A watch means the risk of a dangerous weather event has increased. But its exact timing or location is still uncertain. It gives people time to prepare their safety plans. A watch means hazardous weather is possible, but not happening right now. People should have a plan and listen for more information.
- Warning: A warning is issued when a dangerous weather event is happening, about to happen, or very likely. A warning means weather conditions threaten life or property. People in the storm's path need to take action to protect themselves.
- Special Weather Statement (or Significant Weather Advisory): This is issued for something rare or unusual. It's often for sudden weather changes. These statements can act as warnings for a specific area. Significant Weather Advisories are for storms not severe enough for a Severe Thunderstorm Warning, but still have strong winds or small hail.
Weather Warnings and Advisories
Local NWS offices issue short-term weather warnings and advisories. These usually cover areas less than 5,000 square miles. Warnings for severe local storms are usually issued less than an hour before the storm arrives. The NWS also issues warnings for floods, high winds, winter storms, heat, cold, fire weather, and marine hazards.
The NWS defines a warning as a "hazardous weather or hydrologic event [that] is occurring, is imminent, or has a very high probability of occurring." An advisory "[highlights] special weather conditions that are less serious than a warning." Warnings tell people to take immediate action. Advisories suggest caution.
The process starts with observations of a dangerous event. This can be from radar, TV/radio reports, or ground observations. If a warning is needed, the Weather Forecast Office creates a bulletin. This alert is then sent out through many channels. It goes to media, agencies, the internet, NOAA satellites, and NOAA Weather Radio.
The alert tells you the type of alert, the office that issued it, the areas covered, and when it expires. Some alerts, like tornado warnings, trigger the Emergency Alert System. This sends messages to TVs, radios, and phones. For local storms, the warning also describes the storm's location, hazards, and affected towns. It also gives safety advice.
Since 2007, the NWS uses "storm-based warnings." Instead of whole counties, warnings are drawn as polygonal shapes on maps. These shapes outline the specific areas the storm is expected to affect. Warnings can be expanded, shrunk, or canceled by local NWS offices.
NOAA Weather Radio All Hazards (NWR) is like "The Voice of the National Weather Service." It's a special radio system that broadcasts weather watches, warnings, and forecasts 24 hours a day. It comes directly from a nearby NWS office. This system covers most of the United States. NWR has 1,030 transmitters. You need a special radio receiver to pick up the signal. NWR can also broadcast other emergency alerts, not just weather.
The NOAA Weather Wire Service (NWWS) is a satellite system. It sends weather information to government, businesses, media, and people. It started in 2000. Warnings get the highest priority. NWWS delivers severe weather warnings very quickly, in ten seconds or less.
The Emergency Managers Weather Information Network (EMWIN) helps emergency managers. It gives them free access to NWS warnings, forecasts, and other products. They can get data by radio, internet, or satellite dish.
NOAAPORT is a system that broadcasts NOAA environmental data in real-time. It uses a commercial satellite provider.
The NWS's website, Weather.gov, is full of information. You can find local forecasts by typing in a place name. It has maps of active warnings, radar displays, and climate information. You can also get data feeds for warnings and forecasts. All local NWS offices have their own web pages with local information.
The NWS also provides weather information through the Family of Services (FOS). This is a collection of data communication services. Users can get these services for a fee.
What Technology Does the NWS Use?
The WSR-88D Doppler weather radar system, also called NEXRAD, was developed in the mid-1980s. It was put in place across most of the U.S. by 1997. There are 158 radar sites. This technology is key for warning about severe weather. It has high resolution and can detect motions inside clouds.
NWS meteorologists use an advanced system called the Advance Weather Interactive Processing System (AWIPS). This system helps them view weather information easily. They can also create and send out weather products. The NWS Environmental Modeling Center uses advanced computer models. The Global Forecast System (GFS) is one of these models.
In 2016, the NWS greatly increased the power of its supercomputers. This was to improve the accuracy of its GFS weather model. Other models, like the one from the European Centre for Medium-Range Weather Forecasts, sometimes predicted events like Hurricane Sandy more accurately. The new supercomputers made the NWS's computing power much stronger.
How Is the NWS Organized?
The National Weather Service has many parts that work together:
- National Centers for Environmental Prediction (NCEP)
- Aviation Weather Center (AWC)
- Climate Prediction Center (CPC)
- Environmental Modeling Center (EMC)
- Weather Prediction Center (WPC)
- Ocean Prediction Center (OPC)
- Space Weather Prediction Center (SWPC)
- Storm Prediction Center (SPC)
- National Hurricane Center (NHC)
- 6 Regions (Eastern, Central, Southern, Western, Alaska & Pacific)
- 122 Weather Forecast Offices (WFOs)
- 21 Center Weather Service Units (CWSU)
- 13 River Forecast Centers (RFC)
- Pacific Tsunami Warning Center (PTWC)
- National Tsunami Warning Center (NTWC)
- Spaceflight Meteorology Group (SMG)
Why Were There Attempts to Change the NWS?
Some people have felt that the National Weather Service competes unfairly with private weather companies. NWS forecasts and data are free to the public. Sometimes, there are discussions about making the NWS more private.
The 1983 Proposal to Sell Satellites
In 1983, the Reagan administration suggested selling all of the NWS's weather satellites. The idea was to buy weather data back from private companies. This plan also suggested laying off some NWS workers and cutting certain forecasts. Many people, including the public and members of Congress, did not like this idea. They worried that public weather information would be sold for profit. The plan to sell the satellites failed in Congress.
The 2005 Santorum Proposal
In 2005, Senator Rick Santorum proposed a bill. This bill would have stopped the NWS from giving out weather data for free. Many users of NWS services, especially emergency managers, strongly criticized this. They rely on the NWS for information during fires, floods, and severe weather. Groups like the Aircraft Owners and Pilots Association said it would threaten air safety. The bill did not pass.
Why Are Forecasts Sometimes Not Perfect?
Some experts, like Professor Cliff Mass, have said that NWS forecasts could be more accurate. They claim this leads to less accurate daily forecasts and problems predicting extreme weather. In 2016, other weather centers were sometimes cited as producing more accurate predictions.
Reasons suggested for this include:
- Not enough computing power for better simulations.
- Not using new techniques from research.
- Not using data from all available sources, like from commercial airplanes.
- Older equipment on weather satellites.
- Too many different models instead of focusing on a few high-quality ones.
- Problems with how the organization works.
- Resistance to change from employee groups.
The NWS has a project called the Next Generation Global Prediction System. It aims to fix some of these issues by using a unified, high-quality model. In 2016, NOAA announced they would develop this new system.
See also
In Spanish: Servicio Meteorológico Nacional (Estados Unidos) para niños
- Reginald Fessenden – known for proving the practicality of using a network of coastal radio stations to transmit weather information
- Meteorological Service of Canada – a Canadian weather forecasting agency operated under Environment Canada, founded in 1876
- NOAA's Environmental Real-time Observation Network
- Radar Operations Center
Images for kids
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The logo of the National Weather Service.
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The NWS headquarters in Silver Spring, Maryland.
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A sample map showing maximum temperatures from the NDFD.
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NWS IMET Chris Gibson taking observations in the field.
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Map of NWS Weather Forecast Offices.
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Meteorologists preparing a forecast, early 20th century.
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National AHPS map.
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The National Weather Service areas of marine weather forecasting responsibility.
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A sample CPC 3.5-month temperature outlook.
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An Automated Surface Observing System (ASOS).
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A Cooperative Observer Program weather station.
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A 3-meter discus buoy off the Southeast U.S. coast.
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A radiosonde shortly after launch.
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A NWS composite radar image of the Continental United States.
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A special hurricane-proof building for the Houston-Galveston NWS Forecast Office and the Galveston County Emergency Management Office.
