Weather Research and Forecasting Model

{{Short description|Numerical weather prediction system}}

File:Typhoon Mawar 2005 computer simulation thumbnail.gif at 3.3-km (2.1-mi) grid spacing. Time period is from 0000 UTC 22 August 2005 to 0000 UTC 24 August 2005.]]

The Weather Research and Forecasting (WRF) Model{{Cite web|url=https://www.mmm.ucar.edu/weather-research-and-forecasting-model| title=WRF Model site}} ({{IPAc-en|ˈ|w|ɔr|f}}) is a numerical weather prediction (NWP) system designed to serve both atmospheric research and operational forecasting needs, developed in the United States. NWP refers to the simulation and prediction of the atmosphere with a computer model, and WRF is a set of software for this. WRF features two dynamical (computational) cores (or solvers), a data assimilation system, and a software architecture allowing for parallel computation and system extensibility. The model serves a wide range of meteorological applications across scales ranging from meters to thousands of kilometers.

The effort to develop WRF began in the latter part of the 1990s and was a collaborative partnership principally among the National Center for Atmospheric Research (NCAR), the National Oceanic and Atmospheric Administration (represented by the National Centers for Environmental Prediction (NCEP) and the (then) Forecast Systems Laboratory (FSL)), the Air Force Weather Agency (AFWA), the Naval Research Laboratory (NRL), the University of Oklahoma (OU), and the Federal Aviation Administration (FAA).{{Cite web|url=https://www.ucar.edu/news/releases/2006/wrf.shtml |archive-url=https://web.archive.org/web/20060901075715/https://www.ucar.edu/news/releases/2006/wrf.shtml |url-status=dead |archive-date=1 September 2006 |publisher=NCAR |title=Weather Forecast Accuracy Gets Boost with New Computer Model |date=25 August 2006 |access-date=27 June 2010 }} The bulk of the work on the model has been performed or supported by NCAR, NOAA, and AFWA.

WRF allows researchers to produce simulations reflecting either real data (observations, analyses) or idealized atmospheric conditions. WRF provides operational forecasting a flexible and robust platform, while offering advances in physics, numerics, and data assimilation contributed by the many research community developers. WRF is currently in operational use at NCEP and other forecasting centers internationally. WRF has grown to have a large worldwide community of users (over 30,000 registered users in over 150 countries), and workshops and tutorials are held each year at NCAR. WRF is used extensively for research and real-time forecasting throughout the world. It has been shown to perform well in simulating atmospheric convection,{{Cite journal|doi=10.1175/MWR2830.1|title=Evaluating Mesoscale NWP Models Using Kinetic Energy Spectra|year=2004|last1=Skamarock|first1=William C.|journal=Monthly Weather Review|volume=132|issue=12|pages=3019–3032|bibcode=2004MWRv..132.3019S|doi-access=free}}{{Cite journal|doi=10.1175/MWR-D-15-0326.1|title=Evolution of the Diurnal Precipitation Cycle with the Passage of a Madden–Julian Oscillation Event through the Maritime Continent|year=2016|last1=Vincent|first1=Claire L.|last2=Lane|first2=Todd P.|journal=Monthly Weather Review|volume=144|issue=5|pages=1983–2005|bibcode=2016MWRv..144.1983V|doi-access=free|hdl=11343/197698|hdl-access=free}} but to be prone to producing squall lines too easily.{{Cite journal| doi=10.1002/qj.3855| title=Locally forced convection in sub‐kilometre scale simulations with the Unified Model and WRF| year=2020| last1=Jucker| first1=M.| last2=Lane| first2=T.P.| last3=Vincent| first3=C.L.| last4=Webster| first4=S.| last5=Wales| first5=S.A.| last6=Louf| first6=V.| journal=Quarterly Journal of the Royal Meteorological Society| volume=146| issue=732| pages=3450–3465| bibcode=2020QJRMS.146.3450J| doi-access=free| hdl=11343/241629| hdl-access=free}}

WRF offers two dynamical solvers for its computation of the atmospheric governing equations, and the variants of the model are known as WRF-ARW (Advanced Research WRF) and WRF-NMM (nonhydrostatic mesoscale model). The Advanced Research WRF (ARW) is supported to the community by the NCAR Mesoscale and Microscale Meteorology Laboratory.{{Cite web|url=https://www.mmm.ucar.edu/wrf-user-support-contributor-information|title=WRF User Support & Contributor Information | MMM: Mesoscale & Microscale Meteorology Laboratory|website=www.mmm.ucar.edu}} The WRF-NMM solver variant was based on the Eta model, and later nonhydrostatic mesoscale model, developed at NCEP. The WRF-NMM (NMM) is supported to the community by the Developmental Testbed Center (DTC).

The WRF serves as the basis for the RAP and HRRR models: high-resolution operational forecast models run regularly at NCEP. The WRF also serves as the basis for the North American Mesoscale (NAM) model at 12km and 3km grid resolutions. {{Cite web|url=https://rapidrefresh.noaa.gov/RR.faq.html|title=Rapid Refresh Frequently Asked Questions|website=rapidrefresh.noaa.gov}}{{cite web|url=https://dtcenter.org/plots/hwt/model.php|archive-url=https://web.archive.org/web/20150218185729/https://dtcenter.org/plots/hwt/model.php|title=HWT 2009 Spring Experiment Objective Verification|archive-date=2015-02-18}}

A version of WRF-NMM tailored for hurricane forecasting, HWRF (hurricane weather research and forecasting), became operational in 2007.{{Cite web|url=http://www.noaanews.noaa.gov/stories2007/s2885.htm |publisher=NOAA News Online |title=New Advanced Hurricane Model Aids NOAA Forecasters |date=27 June 2007 |access-date=27 June 2010 }}

In 2009, a polar optimized WRF was released through the Byrd Polar Research Center at the Ohio State University.{{Cite web|url=http://polarmet.osu.edu/PolarMet/pwrf.html |publisher=The Ohio State University Polar Meteorology Group |title=The Polar WRF |date=17 September 2009 |access-date=31 July 2014 }}