Agency overview | |
---|---|
Formed | 1942 |
Jurisdiction | United States government |
Headquarters | College Park, Maryland |
Agency executives |
|
Website | http://www.wpc.ncep.noaa.gov |
The Weather Prediction Center (WPC), located in College Park, Maryland, is one of nine service centers under the umbrella of the National Centers for Environmental Prediction (NCEP), a part of the National Weather Service (NWS), which in turn is part of the National Oceanic and Atmospheric Administration (NOAA) of the U.S. Government. Until March 5, 2013, the Weather Prediction Center was known as the Hydrometeorological Prediction Center (HPC). The Weather Prediction Center serves as a center for quantitative precipitation forecasting, medium range forecasting (three to eight days), and the interpretation of numerical weather prediction computer models.
The Weather Prediction Center issues storm summaries on storm systems bringing significant rainfall and snowfall to portions of the United States. They also forecast precipitation amounts for the lower 48 United States for systems expected to impact the country over the next seven days. Advisories are also issued for tropical cyclones which have moved inland, weakened to tropical depression strength, and are no longer the responsibility of the National Hurricane Center. The Weather Prediction Center also acts as the backup office to the National Hurricane Center in the event of a complete communications failure.
Long range climatological forecasts are produced by the Climate Prediction Center (CPC), a branch of the National Weather Service. These include 8–14 day outlooks, monthly outlooks, and seasonal outlooks.
From the early days of organized weather collection in the United States, a central facility was used to gather and disseminate data. Originally, this task occupied[ when? ] a single room within the United States Army Signal Service in Washington, D.C. Reports were collected via telegraph and general forecasts were made for the country.[ citation needed ]
While WPC's roots lie deep in the past,[ when? ] the organization can be most directly traced to the formation of the Analysis Center by Circular Letter 39-42, signed by Weather Bureau Director Francis W. Reichelderfer on March 5, 1942. [1] [2] Operations began on March 16, 1942, with the unit collocated with the Weather Bureau Central Office at 24th and M Streets NW in Washington, D.C. [3] Initially the unit was sometimes referred to as the Master Analysis Center.
In 1947, the Analysis Center was combined with the Air Force Master Analysis Center and the Navy Weather Central to create the Weather Bureau-Air Force-Navy (WBAN) Analysis Center. Their operations commenced on June 16, 1947, at 24th and M Streets NW. By early 1950 the WBAN Analysis Center consisted of 150 employees. [4] Medium range forecasting was done nationally to 54 hours in the future. [4] Charts and maps were created at this facility for national distribution. [5]
In July 1954, the Joint Numerical Weather Prediction Unit (JNWPU) was created to test out numerical weather prediction (NWP) techniques by computer. This unit co-located with the WBAN analysis center to form the National Weather Analysis Center, which was located in Suitland, Maryland. When the two units merged, the name changed to the National Meteorological Center (NMC) in January 1958. When the JNWPU dissolved in 1961, NMC became an independent organization from Global Weather Central and Fleet Numerical Weather Central. [6] Research and computer processing abilities increased over the years, which allowed for the first global forecast model to run by June 1966. By January 1975, much of the facility, minus the computers, moved to the World Weather Building, located in nearby Camp Springs, Maryland. [5]
NMC changed its name to NCEP, the National Centers for Environmental Prediction on October 1, 1995. The Hydrometeorological Prediction Center became a subunit of NCEP, as did a number of other national centers such as the Climate Prediction Center (CPC), Environmental Modeling Center (EMC), National Hurricane Center (NHC), Ocean Prediction Center (OPC), Storm Prediction Center (SPC), Aviation Weather Center (AWC), NCEP Central Operations, and the Space Weather Prediction Center (SWPC). [5] During August 2012, HPC moved to a new building, the National Center for Weather and Climate Prediction (NCWCP), in College Park, Maryland. On March 5, 2013, HPC changed its name to the Weather Prediction Center. [7]
The mission of the WPC is to provide forecast, guidance, and analysis products and services to support the daily public forecasting activities of the NWS and its customers, and to provide tailored support to other government agencies in emergency and special situations. [8]
The QPF desks prepare and issue forecasts of accumulating (quantitative) precipitation, heavy rain, heavy snow, and highlights areas with the potential for flash flooding, with forecasts valid over the following five days. These products are sent to the National Weather Service forecast offices and are available on the Internet for public use. Heavy snow forecast products, in association with the short-range public forecast products (described below), serve as a coordinating mechanism for the national winter storm watch and warning program. [9]
One desk of the National Environmental Satellite Data and Information Service (NESDIS) is co-located with the WPC QPF desks, which together form the National Precipitation Prediction Unit (NPPU). NESDIS meteorologists prepare estimates of rainfall and current trends based on satellite data, and this information is used by the Day 1 QPF forecaster to help create individual 6-hourly forecasts that cover the next 12 hours. With access to WSR-88D/Doppler weather radar data, satellite estimates, and NCEP model forecast data as well as current weather observations and WPC analyses, the forecaster has the latest data for use in preparation of short-range precipitation forecasts. Meteorological reasoning discussions are regularly written and issued with the forecast packages to explain and support the forecast. [9]
The WPC Winter Weather Desk issues heavy snow and icing forecast products, which support the NWS winter weather watch/warning/outlook program. These forecasts are for the contiguous United States (CONUS) and issued from September 15 to May 15 each cold season. Graphical forecasts are issued twice daily at 0900 UTC and 2100 UTC (4AM/PM EST respectively), although updates may be warranted by rapidly changing conditions.
The Winter Weather Desk issues probabilistic heavy snow and icing guidance products for the next three days. The forecasts represent the probability that freezing rain or combined snow/sleet accumulations will meet specific criteria within a 24-hour period. These products are issued in probabilistic form to better represent the forecast uncertainty associated with a particular event. The Winter Weather Desk produces a heavy snow and icing discussion that provides the meteorological reasoning for the 24-hour probabilistic heavy snow and icing guidance graphics. This text message is used by internal and external clients including NWS field offices, Department of Homeland Security, FEMA, the White House, Department of Commerce, FAA, and the general meteorological community (private sector and the media). [9]
The short range forecasters are responsible for preparing forecasts for the time period of 6 through 60 hours. These products are issued twice daily using guidance from the NWS's Global Forecast System (GFS) and North American Mesoscale Model (NAM), as well as guidance from the European Centre for Medium-Range Weather Forecasts (ECMWF), the United Kingdom's Met Office (UKMET), the Meteorological Service of Canada, including ensembles. Coordination with the surface analysis, model diagnostics, quantitative precipitation, winter weather, and tropical forecast desks is performed during the short range forecast process to maintain internal consistency. The short range forecast products include surface pressure patterns, circulation centers and fronts for 6–60 hours, and a depiction of the types and extent of precipitation that are forecast at the valid time of the chart. In addition, discussions are written on each shift and issued with the forecast packages that highlight the meteorological reasoning behind the forecasts and significant weather across the continental United States. [9]
Medium range forecasters are responsible for preparing forecasts for three to seven days into the future. Surface pressure forecasts are issued three times per day, with temperature and probability of precipitation products issued twice per day, using guidance from the NWS medium range forecast model (GFS) as well as models from the European Centre for Medium Range Weather Forecasting (ECMWF), the United Kingdom's Meteorology Office (UKMET), Canadian model, the Navy NOGAPS model, and ensemble guidance from the GFS, ECMWF, Canadian, and North American Ensemble Forecast System (NAEFS).
The medium range forecast products include surface pressure patterns, circulation centers and fronts, daily maximum and minimum temperatures and anomalies, probability of precipitation in 12-hour increments, total 5-day precipitation accumulation for the next five days, and 500 hPa (mb) height forecasts for days 3–7. In addition, a narrative is issued for each set of forecasts highlighting forecast reasoning and significant weather over the Continental United States. Separate forecasts, similar to the 5-day mean products, are prepared for Hawaii. [9]
The Alaska medium range forecasters review the latest deterministic and ensemble model guidance (similar to how the broader medium range forecasts are created) in an effort to compose the most likely forecast for Alaska and surrounding areas valid from four to eight days into the future.
The Alaska medium range discussion, 500 hPa height graphics, and surface fronts and pressures graphics for days 4–8 are issued once per day, year-round. Additionally, gridded guidance for the forecast period is issued for the following fields: maximum/minimum temperature grids, twelve-hour probability of precipitation grids, as well as derived dewpoint temperature, cloud cover, precipitation type, and wind speed/direction grids at a 5 km (3.1 mi) horizontal resolution. [9]
The purpose of the WPC Model Diagnostic Discussion is to provide objective information and subjective interpretation concerning the current runs of the NCEP short range numerical models. The WPC model diagnostic meteorologist prepares the Model Diagnostic Discussion twice per day in two parts, corresponding to the 0000 UTC and 1200 UTC model runs. This narrative consists of three sections: an evaluation of the initialization of the NAM and GFS, a review of model trends and biases, and a description of model differences and preferences. The meteorologist reviews how the suite of models from the latest forecast cycle differ from each other in their forecasts of significant features, and makes a preference based upon all relevant current information. [9]
The WPC Surface Analysis is part of the NWS Unified Surface Analysis and a collaborative effort with the Ocean Prediction Center, the National Hurricane Center, and the Honolulu Weather Forecast Office. The WPC focuses on the synoptic and mesoscale features over North America, primarily north of 31N. The surface analysis is a manual analysis of surface fronts and pressure over North America and adjacent oceans performed every three hours. The analysis utilizes a variety of weather data in addition to observations of surface weather conditions, such as upper air observations, global satellite imagery, Doppler weather radar, and model mass fields to ensure that the product is meteorologically consistent. [9]
The WPC is the official backup center to the National Hurricane Center (NHC). In this capacity, the WPC is responsible for issuing all tropical cyclone products, including discussions, graphics and watches and warnings that would normally be issued by the NHC for any tropical system in the Atlantic Ocean, if NHC is unable to so. [9]
During the tropical weather season which runs from May 15 – November 30, the WPC has several other routine duties pertaining to tropical weather forecasting. Through 2008, WPC provided track forecast guidance to the NHC whenever there is a tropical cyclone in the Atlantic Ocean basin west of 60W longitude. As required, this guidance is provided to the NHC four times daily for use in the tropical cyclone package issued by the NHC at 0300 UTC, 0900 UTC, 1500 UTC and 2100 UTC. The WPC participates in the Hurricane Hotline call with the NHC and other forecast offices and government agencies at 1700 UTC for tropical cyclones in the Atlantic Ocean basin west of 60W longitude. Also, points for days 6 and 7 for existing tropical cyclones east of 140W longitude, [10] and days 3–7 to possible future tropical cyclones, are coordinated between the medium range pressures desk and NHC each day at 1700 UTC during the hurricane season. This coordination call began between the Extended Forecast Section and the Miami Hurricane Warning Office prior to 1959. [11]
Within the WPC tropical program, the lead forecaster on shift, who prepares the day 1 QPF, is to provide the rainfall statement for tropical cyclones that are expected to make landfall. This statement is included in the Public Advisory issued by the NHC, and is a forecast of expected rainfall amounts that will occur with the tropical cyclone. [12]
Finally, the WPC surface analysis desk has the responsibility for issuing Public Advisories whenever a tropical cyclone has made landfall in the U.S. or adjacent parts of Mexico, has weakened below tropical storm status (i.e. to a tropical depression or post-tropical cyclone or low) and is not expected to re-emerge over water as a tropical cyclone, yet the system is still capable of producing flooding type rains. This WPC Public Advisory will continue to be issued until the flooding rainfall threat is over. The advisory will contain information on how much rainfall has occurred with a particular tropical system, and will also include forecast information on the remnants of the system. [9] This responsibility has been held by the center since 1973.
Short-term forecasts are made at the meteorological watch (metwatch) desk. It issues mesoscale precipitation discussions (MPDs) as flash flood guidance for NWS forecast offices (NWSFOs), NWS River Forecast Centers (RFCs), the media, emergency managers, and other users. MPDs contain technical discussions concerning heavy rainfall events and expected impacts on flash flooding. They are ideally issued 1–6 hours preceding an event, include graphical descriptions of the details and the area covered. Their size typically is about half the size of Kansas. There are three headlines ordered by severity: "flash flooding likely", "flash flooding possible", or "flash flooding unlikely". [13] Mesoscale discussions (MDs) once were issued by the Storm Prediction Center (SPC) for both convective (MCDs) and precipitation (MPDs) events but WPC now covers this heavy rainfall function.
The International desks have a variety of responsibilities, primarily the training of foreign visitors in the use of Numerical Weather Prediction products. The International desk routinely hosts visitors from Central and South America and the Caribbean. Visiting meteorologists train, and also generate forecasts for their own national centers, and assist WPC forecasters with QPF related to tropical cyclones in Central America and the Caribbean. [9]
The National Hurricane Center (NHC) is the division of the United States' NOAA/National Weather Service responsible for tracking and predicting tropical weather systems between the Prime Meridian and the 140th meridian west poleward to the 30th parallel north in the northeast Pacific Ocean and the 31st parallel north in the northern Atlantic Ocean. The agency, which is co-located with the Miami branch of the National Weather Service, is situated on the campus of Florida International University in University Park, Miami, Florida.
The National Weather Service (NWS) is an agency of the United States federal government that is tasked with providing weather forecasts, warnings of hazardous weather, and other weather-related products to organizations and the public for the purposes of protection, safety, and general information. It is a part of the National Oceanic and Atmospheric Administration (NOAA) branch of the Department of Commerce, and is headquartered in Silver Spring, Maryland, within the Washington metropolitan area. The agency was known as the United States Weather Bureau from 1890 until it adopted its current name in 1970.
The Advanced Weather Interactive Processing System (AWIPS) is a technologically advanced processing, display, and telecommunications system that is the cornerstone of the United States National Weather Service's (NWS) operations.
The Environmental Modeling Center (EMC) is a United States Government agency, which improves numerical weather, marine and climate predictions at the National Centers for Environmental Prediction (NCEP), through a broad program of research in data assimilation and modeling. In support of the NCEP operational forecasting mission, the EMC develops, improves and monitors data assimilation systems and models of the atmosphere, ocean and coupled system, using advanced methods developed internally as well as cooperatively with scientists from universities, NOAA laboratories and other government agencies, and the international scientific community.
This is a list of meteorology topics. The terms relate to meteorology, the interdisciplinary scientific study of the atmosphere that focuses on weather processes and forecasting.
A Pacific hurricane is a tropical cyclone that develops within the northeastern and central Pacific Ocean to the east of 180°W, north of the equator. For tropical cyclone warning purposes, the northern Pacific is divided into three regions: the eastern, central, and western, while the southern Pacific is divided into 2 sections, the Australian region and the southern Pacific basin between 160°E and 120°W. Identical phenomena in the western north Pacific are called typhoons. This separation between the two basins has a practical convenience, however, as tropical cyclones rarely form in the central north Pacific due to high vertical wind shear, and few cross the dateline.
A tropical cyclone forecast model is a computer program that uses meteorological data to forecast aspects of the future state of tropical cyclones. There are three types of models: statistical, dynamical, or combined statistical-dynamic. Dynamical models utilize powerful supercomputers with sophisticated mathematical modeling software and meteorological data to calculate future weather conditions. Statistical models forecast the evolution of a tropical cyclone in a simpler manner, by extrapolating from historical datasets, and thus can be run quickly on platforms such as personal computers. Statistical-dynamical models use aspects of both types of forecasting. Four primary types of forecasts exist for tropical cyclones: track, intensity, storm surge, and rainfall. Dynamical models were not developed until the 1970s and the 1980s, with earlier efforts focused on the storm surge problem.
The Servicio Meteorológico Nacional is Mexico's national weather organization. It collects data and issues forecasts, advisories, and warnings for the entire country.
Tropical cyclone track forecasting involves predicting where a tropical cyclone is going to track over the next five days, every 6 to 12 hours. The history of tropical cyclone track forecasting has evolved from a single-station approach to a comprehensive approach which uses a variety of meteorological tools and methods to make predictions. The weather of a particular location can show signs of the approaching tropical cyclone, such as increasing swell, increasing cloudiness, falling barometric pressure, increasing tides, squalls and heavy rainfall.
The quantitative precipitation forecast is the expected amount of melted precipitation accumulated over a specified time period over a specified area. A QPF will be created when precipitation amounts reaching a minimum threshold are expected during the forecast's valid period. Valid periods of precipitation forecasts are normally synoptic hours such as 00:00, 06:00, 12:00 and 18:00 GMT. Terrain is considered in QPFs by use of topography or based upon climatological precipitation patterns from observations with fine detail. Starting in the mid-to-late 1990s, QPFs were used within hydrologic forecast models to simulate impact to rivers throughout the United States. Forecast models show significant sensitivity to humidity levels within the planetary boundary layer, or in the lowest levels of the atmosphere, which decreases with height. QPF can be generated on a quantitative, forecasting amounts, or a qualitative, forecasting the probability of a specific amount, basis. Radar imagery forecasting techniques show higher skill than model forecasts within 6 to 7 hours of the time of the radar image. The forecasts can be verified through use of rain gauge measurements, weather radar estimates, or a combination of both. Various skill scores can be determined to measure the value of the rainfall forecast.
The Hurricane Weather Research and Forecasting (HWRF) model is a specialized version of the weather research and forecasting model and is used to forecast the track and intensity of tropical cyclones. The model was developed by the National Oceanic and Atmospheric Administration (NOAA), the U.S. Naval Research Laboratory, the University of Rhode Island, and Florida State University. It became operational in 2007.
The Hurricane Databases (HURDAT), managed by the National Hurricane Center (NHC), are two separate databases that contain details on tropical cyclones that have occurred within the Atlantic Ocean and Eastern Pacific Ocean since 1851 and 1949 respectively.
The Ocean Prediction Center (OPC), established in 1995, is one of the National Centers for Environmental Prediction's (NCEP's) original six service centers. Until 2003, the name of the organization was the Marine Prediction Center. Its origins are traced back to the sinking of the RMS Titanic in 1912. The OPC issues forecasts up to five days in advance for ocean areas north of 31° north latitude and west of 35° west longitude in the Atlantic, and across the northeast Pacific north of 30° north latitude and east of 160° east longitude. Until recently, the OPC provided forecast points for tropical cyclones north of 20° north latitude and east of the 60° west longitude to the National Hurricane Center. OPC is composed of two branches: the Ocean Forecast Branch and the Ocean Applications Branch.
The history of Atlantic tropical cyclone warnings details the progress of tropical cyclone warnings in the North Atlantic Ocean. The first service was set up in the 1870s from Cuba with the work of Father Benito Viñes. After his death, hurricane warning services were assumed by the US Army Signal Corps and United States Weather Bureau over the next few decades, first based in Jamaica and Cuba before shifting to Washington, D.C. The central office in Washington, which would evolve into the National Meteorological Center and the Weather Prediction Center, assumed the responsibilities by the early 20th century. This responsibility passed to regional hurricane offices in 1935, and the concept of the Atlantic hurricane season was established to keep a vigilant lookout for tropical cyclones during certain times of the year. Hurricane advisories issued every 12 hours by the regional hurricane offices began at this time.
The following is a glossary of tornado terms. It includes scientific as well as selected informal terminology.
Hurricane Isaias was a destructive tropical cyclone that caused extensive damage across the Caribbean and the East Coast of the United States while also spawning the strongest tropical cyclone-spawned tornado since Hurricane Rita in 2005. The ninth named storm and second hurricane of the extremely active and record-breaking 2020 Atlantic hurricane season, Isaias originated from a vigorous tropical wave off the coast of Africa that was first identified by the National Hurricane Center on July 23. The tropical wave gradually became more organized and obtained gale-force winds on July 28 before organizing into Tropical Storm Isaias on July 30. Isaias marked the earliest ninth named storm on record, surpassing 2005's Hurricane Irene by eight days. Isaias strengthened into a Category 1 hurricane on the next day, reaching an initial peak of 85 mph (140 km/h), with a minimum central pressure of 987 mbar. On August 1, the storm made landfall on North Andros, Bahamas and subsequently weakened to a tropical storm, before paralleling the east coast of Florida and Georgia. As Isaias approached the Carolina coastline, it reintensified back into a hurricane. Soon afterward, Isaias reached its peak intensity, with maximum 1-minute sustained winds of 90 mph (150 km/h) and a minimum central pressure of 986 millibars (29.1 inHg), before making landfall near Ocean Isle Beach, North Carolina, at 03:10 UTC on August 4, at the same intensity. The storm proceeded to accelerate up the East Coast of the United States as a strong tropical storm, before transitioning into an extratropical cyclone over Quebec on August 4. Isaias's extratropical remnants persisted for another day, before dissipating on August 5.
Hurricane Genevieve was a strong tropical cyclone that almost made landfall on the Baja California Peninsula in August 2020. Genevieve was the twelfth tropical cyclone, seventh named storm, third hurricane, and second major hurricane of the 2020 Pacific hurricane season. The cyclone formed from a tropical wave that the National Hurricane Center (NHC) first started monitoring on August 10. The wave merged with a trough of low pressure on August 13, and favorable conditions allowed the wave to intensify into Tropical Depression Twelve-E at 15:00 UTC. Just six hours later, the depression became a tropical storm and was given the name Genevieve. Genevieve quickly became a hurricane by August 17, and Genevieve began explosive intensification the next day. By 12:00 UTC on August 18, Genevieve reached its peak intensity as a Category 4 hurricane, with maximum 1-minute sustained winds of 130 mph and a minimum central pressure of 950 millibars (28 inHg). Genevieve began to weaken on the next day, possibly due to cooler waters caused by Hurricane Elida earlier that month. Genevieve weakened below tropical storm status around 18:00 UTC on August 20, as it passed close to Baja California Sur. Soon afterward, Genevieve began to lose its deep convection and became a post-tropical cyclone by 21:00 UTC on August 21, eventually dissipating off the coast of Southern California late on August 24.
Hurricane Laura tied the record for the strongest hurricane to make landfall in Louisiana as measured by maximum sustained winds, along with the 1856 Last Island hurricane and Hurricane Ida, and was overall the tenth-strongest hurricane to make landfall in the United States. The thirteenth tropical cyclone, twelfth named storm, fourth hurricane, and first major hurricane of the 2020 Atlantic hurricane season, Laura originated from a large tropical wave that moved off the West African coast on August 16. The tropical wave gradually organized, becoming a tropical depression on August 20. Though in only a marginally conducive environment for intensification, the depression nevertheless intensified into a tropical storm a day later, becoming the earliest twelfth named storm on record in the North Atlantic basin, forming eight days earlier than 1995's Hurricane Luis. The depression received the name Laura and tracked west-northwest towards the Lesser Antilles.
Tropical Storm Beta was a tropical cyclone that brought heavy rainfall, flooding, and severe weather to the Southeastern United States in September 2020. The twenty-third tropical depression and twenty-third named storm of the record-breaking 2020 Atlantic hurricane season, Beta originally formed from a trough of low pressure that developed in the northeastern Gulf of Mexico on September 10. The low moved slowly southwestward, with development hampered initially by the development of nearby Hurricane Sally. After Sally moved inland over the Southeastern United States and weakened, the disturbance became nearly stationary in the southwestern Gulf, where it began to organize. By September 16, the storm had gained a low-level circulation center and had enough organization to be designated as Tropical Depression Twenty-Two. The system held its intensity for a day due to the influence of strong wind shear and dry air, before eventually attaining tropical storm strength. It slowly moved northward and intensified to a mid-range tropical storm before dry air and wind shear halted its intensification. Beta then became nearly stationary on September 19, before starting to move west towards the Texas coast the next day, weakening as it approached. On September 21, Beta made landfall near Matagorda Peninsula, Texas as a minimal tropical storm. It subsequently weakened to a tropical depression the next day before becoming post-tropical early on September 23. Its remnants moved northeastward, before the center elongated and merged with a cold front early on September 25.
An extremely powerful extratropical cyclone began in late October 2021 in the Northeast Pacific and struck the Western United States and Western Canada. The storm was the third and the most powerful cyclone in a series of powerful storms that struck the region within a week. The cyclone tapped into a large atmospheric river and underwent explosive intensification, becoming a bomb cyclone on October 24. The bomb cyclone had a minimum central pressure of 942 millibars (27.8 inHg) at its peak, making it the most powerful cyclone recorded in the Northeast Pacific. The system had severe impacts across Western North America, before dissipating on October 26. The storm shattered multiple pressure records across parts of the Pacific Northwest. Additionally, the bomb cyclone was the most powerful storm on record to strike the region, in terms of minimum central pressure. The bomb cyclone brought powerful gale-force winds and flooding to portions of Western North America. At its height, the storm cut the power to over 370,500 customers across the Western U.S. and British Columbia. The storm killed at least two people; damage from the storm was estimated at several hundred million dollars. The bomb cyclone was compared to the Columbus Day Storm of 1962, in terms of ferocity.
{{cite web}}
: CS1 maint: numeric names: authors list (link){{cite web}}
: CS1 maint: numeric names: authors list (link){{cite web}}
: CS1 maint: numeric names: authors list (link){{cite book}}
: CS1 maint: multiple names: authors list (link)This article incorporates public domain material from "Hydrometeorological Prediction Center". National Weather Service. NOAA.