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John M. Brown authored and/or contributed to the following articles/publications.
An Intercomparison of T-REX Mountain-Wave Simulations and Implications for Mesoscale Predictability
Numerical simulations of flow over steep terrain using 11 different nonhydrostatic numerical models are compared and analyzed. A basic benchmark and five other test cases are simulated in a two-dimensional framework using the same initial state, which is based on conditions during Intensive Observation Period (IOP) 6 of the Terrain-Induced Rotor...
The Rapid Refresh (RR) is a 1-h data assimilation system at 13-km grid spacing, which provides mesoscale guidance for short-range forecasts. Among the many significant weather phenomena, the RUC is relied upon for the prediction of turbulence and high speed wind events by the marine and aviation industries. The Rapid Refresh (RR) forecast model ...
Institution National Oceanic and Atmospheric Administration - NOAA
The High Resolution Rapid Refresh (HRRR) is a 3-km, convection resolving model, run hourly in real-time at the Global System Division (GSD) of the NOAA Earth System Research Laboratory (ESRL). The WRF-ARW-based HRRR is run out to fifteen hours over a domain covering the entire continental United States (CONUS), using initial and boundary conditi...
The prediction of winds between 50 and 150 m above ground level (AGL) is crucial for the design, operation, and maintenance of wind farms. The lack of standard observations in this layer makes the development and verification of numerical weather prediction models difficult for wind energy purposes. Specifically, this data limitation has resulte...
The coastal region of western North America frequently experiences intense orographically enhanced wind and rainfall when cyclones make landfall. The prefrontal lowlevel winds can undergo upstream deceleration and deflection in the coastal regions, producing strong barrier jets (Macklin et al. 1990; Overland and Bond 1993 and 1995; Loescher et a...
Use of lightning data to enhance radar assimilation within the RUC and Rapid Refresh models
An ongoing research effort within NOAA ESRL/GSD has focused on incorporating lighting data into the RUC and Rapid Refresh analysis systems. For both systems, lightning data are converted to proxy radar reflectivity data using simple assumptions. Within the RUC, latent heating-based temperature tendency fields are then created, which are used to ...
For the past four years, The ESRL Global Systems Divisions has produced probabilistic thunderstorm likelihood forecasts by applying statistical post-processing techniques to timelagged ensembles of Rapid Update Cycle (RUC) model output. Since March of 2005, these forecasts have been distributed in real-time to the Aviation Weather Center (AWC) a...
Statistical modeling of downslope windstorms in Boulder, Colorado
Downslope windstorms are of major concern to those living in and around Boulder, Colorado, often striking with little warning, occasionally bringing clear-air wind gusts of 35–50 m s1 or higher, and producing widespread damage. Historically, numerical models used for forecasting these events had lower than desired accuracy. This observation prov...
The RTMA Background - Hourly Downscaling of RUC Data to 5-KM Detail
The Real-Time Mesoscale Analysis is designed to provide the best 5-km gridded estimate of current surface and near-surface conditions on an hourly basis in support of National Weather Service activities and the NWS National Digital Forecast Database (NDFD). Even with availability of increasingly dense mesonet observations, the RTMA must incorpor...
FIM: A vertically flow-following, finite-volume icosahedral model
Global Spectral models have gained almost universal acceptance in the last several decades. However, drawbacks of high-resolution spectral models in terms of operation counts and communication overheads on massive parallel processors have led, in recent years, to the development of new types of grid-point global models discretized on geodesic gr...
Numerical Simulations of the wake of Kauai
This study uses a series of numerical simulations to examine the structure of the wake of the Hawaiian island of Kauai. The primary focus is on the conditions on 26 June 2003, which was the day of the demise of the Helios aircraft within Kauai's wake. The simulations show that, in an east-northeasterly trade wind flow, Kauai produces a well-def...
Assimilation of lightning data into RUC model convection forecasting
Lightning data have been used experimentally as part of the NOAA Rapid Update Cycle (RUC) assimilation method for improving cloud/hydrometeor/convection initialization. Lightning data can be used to supplement initial information on existence of convection, along with radar and satellite data and a short-range background model forecast. Radar re...
Development of FAA national ceiling and visibility products: Challenges, strategies, and progress
The complex physical processes controlling ceiling and visibility (for example, the formation, evolution and motion of low cloud, precipitation and fog) and the diverse seasonal and geographic influences that modulate these controls across the continen-tal U.S. and Alaska yield an extremely difficult analysis and forecast problem. This same phen...
Statistical Modeling of Downslope Windstorms in Boulder, Colorado
Downslope windstorms are of major concern to those living near the Boulder, Colorado area, often striking with little warning, bringing clear air wind gusts of 35-50 m/s or higher, and producing widespread damage across the city. Models used for forecasting these dangerous events are often not accurate. Hence, there is a need to apply different ...
Aviation users have a strong need for accurate short-range forecasts of sensible weather parameters including clouds, fog, ceiling and visibility and precipitation. Modelbased predictions of these parameters are the main source of guidance beyond a few hours and these predictions depend critically on the accurate initialization of cloud and hydr...
Numerical simulation of the wake of Kauai with implications for the Helios flights
CYCLED SNOW STATE IN RUC COUPLED DATA ASSIMILATION SYSTEM (CDAS)
EXAMINATION OF THE PERFORMANCE OF SEVERAL MESOSCALE MODELS FOR CONVECTIVE FORECASTING DURING IHOP
Cloud/Hydrometeor Initialization in the 20-km RUC Using GOES and Radar Data
Cloud/Hydrometeor Initialization in the 20-km RUC Using Radar and GOES Data
Cloud/Hydrometeor Initialization in the 20-km RUC Using Radar and GOES Data
A new version of the Rapid Update Cycle (RUC) with 20-km resolution and significant changes in model and assimilation techniques is being implemented at NOAA’s National Centers for Environmental Prediction (NCEP) in summer 2001. The RUC, a high-frequency mesoscale analysis and forecast model system, has become a widely used source for short-rang...
COMPARISONS OF RUC 20-KM AND 40-KM FORECASTS FOR 24 MAY 2000
Fine-scale comparison of TOMS total ozone data with model analysis of an intense Midwestern cyclone
High-resolution (similar to 40 km) along-track total column ozone data from the Total Ozone Mapping Spectrometer (TOMS) instrument are compared with a high-resolution mesoscale numerical model analysis of an intense cyclone in the Midwestern United States. Total ozone increased by similar to 100 DU (nearly 38%) as the TOMS instrument passed o...
Forecasting downslope windstorms at Boulder, Colorado: The empirical-statistical approach revisited
Case study verification of RUC/MAPS fog and visibility forecasts
Validation of long-term precipitation and evolved soil moisture and temperature fields in MAPS
Mesoscale circulation growth under conditions of weak inertial instability
The hypothesis that inertial instability plays a role in the upscale development of mesoscale convective systems (MCSs) is explored by sampling environments that supported the growth of MCSs in the Preliminary Regional Experiment for STORM (Stormscale Operational and Research Meteorology) (PRE-STORM) network with high quality special soundings. ...
A collaborative effort toward a future community mesoscale model (WRF)
Comparison of skin temperatures from the MAPS/RUC Forecast Model and from GOES-8
Progress on FIM development toward membership in the North American Ensemble Forecast System
Institution National Oceanic and Atmospheric Administration - NOAA
100 Years of Progress in Forecasting and NWP Applications
Over the past 100 years, the collaborative effort of the international science community, including government weather services and the media, along with the associated proliferation of environmental observations, improved scientific understanding, and growth of technology, has radically transformed weather forecasting into an effective global a...
Institution National Oceanic and Atmospheric Administration - NOAA
Improving Wind Energy Forecasting through Numerical Weather Prediction Model Development
The primary goal of the Second Wind Forecast Improvement Project (WFIP2) is to advance the state-of-the-art of wind energy forecasting in complex terrain. To achieve this goal, a comprehensive 18-month field measurement campaign was conducted in the region of the Columbia River basin. The observations were used to diagnose and quantify systemati...
Institutions National Oceanic and Atmospheric Administration - NOAA Earth System Research Laboratory - ESRL National Center for Atmospheric Research - NCAR
A Description of the MYNN-EDMF Scheme and the Coupling to Other Components in WRF–ARW
The Mellor–Yamada–Nakanishi–Niino (MYNN) (Nakanishi and Niino 2001, 2004, 2006, and 2009) scheme was first integrated into the Advanced Research version of the Weather Research and Forecasting Model (WRF-ARW) version 3.1 (Skamarock et al. 2008) by Mariusz Pagowski of the National Oceanic and Atmospheric Administration (NOAA) Global Systems Divis...
Institution National Oceanic and Atmospheric Administration - NOAA
The High Resolution Rapid Refresh (HRRR) assimilates radar reflectivity information in order to skillfully forecast convection. This assimilation is done using an empirical relationship between reflectivity and latent heat release from hydrometeor condensation and freezing to update the temperature tendency field. The temperature tendency field ...
Institution National Oceanic and Atmospheric Administration - NOAA
The Bay Area Flood Protection Association has just recently begun funding the Physical Sciences Division and Global Systems Division (GSD) of NOAA’s Earth System Research Lab (NOAA-ESRL), as well as the NOAA Cooperative Institute for Research in the Atmosphere (CIRA), to design and build a specialized nowcast / forecast system for the 9 Californ...
Institution National Oceanic and Atmospheric Administration - NOAA
Addressing Common Cloud - Radiation Errors from ~4-hour to 4-week Model Prediction
Cloud-radiation representation in models for subgrid-scale clouds is a known gap from subseasonal-to-seasonal models down to storm-scale models applied for forecast duration of only a few hours. NOAA/ESRL has been applying common physical parameterizations for scale-aware deep/shallow convection and boundary-layer mixing over this wide range of ...
Institution National Oceanic and Atmospheric Administration - NOAA
A new hybrid, sigma-pressure vertical coordinate was recently added to the Weather Research and Forecasting (WRF) model in an effort to reduce numerical noise in the model equations near complex terrain. Testing of this hybrid, terrain-following coordinate was undertaken in the WRF-based Rapid Refresh (RAP) and High-Resolution Rapid Refresh (HRR...
Stratiform Cloud-Hydrometeor Assimilation for HRRR and RAP Model Short-Range Weather Prediction
Accurate cloud and precipitation forecasts are a fundamental component of short-range data assimilation/model prediction systems such as the NOAA 3-km High-Resolution Rapid Refresh (HRRR) or the 13-km Rapid Refresh (RAP). To reduce cloud and precipitation spinup problems, a nonvariational assimilation technique for stratiform clouds was develope...
Institution National Oceanic and Atmospheric Administration - NOAA
A Description of the MYNN Surface-Layer Scheme
The surface-layer scheme controls the degree of coupling between the model surface and the atmosphere. Traditionally, surface-layer schemes have been developed to be paired with certain planetary boundary layer (PBL) schemes, but this singular pairing is too narrow in scope for modern physics suites, since the surfac...
Institution National Oceanic and Atmospheric Administration - NOAA
Spurious mountain-wave features have been reported as false alarms of light-or-stronger numerical weather prediction (NWP)-based cruise level turbulence forecasts especially over the western mountainous region of North America. To reduce this problem, a hybrid sigma-pressure vertical coordinate system was implemented in NOAA’s operational Rapid ...
Institution National Oceanic and Atmospheric Administration - NOAA
Forecasts by mid-2015 for a strong El Niño during winter 2015/16 presented an exceptional scientific opportunity to accelerate advances in understanding and predictions of an extreme climate event and its impacts while the event was ongoing. Seizing this opportunity, the National Oceanic and Atmospheric Administration (NOAA) initiated an El Niño...
Institution National Oceanic and Atmospheric Administration - NOAA
A stochastic parameter perturbation (SPP) scheme consisting of spatially and temporally varying perturbations of uncertain parameters in the Grell–Freitas convective scheme and the Mellor–Yamada–Nakanishi–Niino planetary boundary scheme was developed within the Rapid Refresh ensemble system based on the Weather Research and Forecasting Model. Al...
Institutions National Center for Atmospheric Research - NCAR National Oceanic and Atmospheric Administration - NOAA
This study describes the initial application of radiance bias correction and channel selection in the hourly updated Rapid Refresh model. For this initial application, data from the Atmospheric Infrared Sounder (AIRS) are used; this dataset gives atmospheric temperature and water vapor information at higher vertical resolution and accuracy than ...
Institution National Oceanic and Atmospheric Administration - NOAA
Diagnostic fields developed for hourly updated NOAA weather models
This document describes methods for diagnosing non-prognostic variables from explicit prognostic variables from hourly updated NOAA models. Many of these diagnostics have been developed for specific forecast applications for downstream forecast users over the years; these variables have been output from the Rapid Update Cycle (RUC) model prior t...
Institution National Oceanic and Atmospheric Administration - NOAA
A North American Hourly Assimilation and Model Forecast Cycle: The Rapid Refresh
The Rapid Refresh (RAP), an hourly-updated assimilation and model forecast system, replaced the Rapid Update Cycle (RUC) as an operational regional analysis and forecast system among the suite of models at the NOAA National Centers for Environmental Prediction (NCEP) in 2012. The need for an effective hourly-updated assimilation and modeling sys...
Institution National Oceanic and Atmospheric Administration - NOAA
A hydrostatic global weather prediction model based on an icosahedral horizontal grid and a hybrid terrain-following/isentropic vertical coordinate is described. The model is an extension to three spatial dimensions of a previously developed, icosahedral, shallow-water model featuring user-selectable horizontal resolution and employing indirect ...
Institutions Earth System Research Laboratory - ESRL National Oceanic and Atmospheric Administration - NOAA
The 13-km Rapid Refresh (RAP) and 3-km convective-allowing High-Resolution Rapid Refresh (HRRR) are hourly updating weather forecast models that use a specially configured version of the Advanced Research WRF (ARW) model and assimilate many novel and most conventional observation types on an hourly basis using Gridpoint Statistical Interpolation...
Institution National Oceanic and Atmospheric Administration - NOAA
The Rapid Refresh (RAP) and High-Resolution Rapid Refresh (HRRR), both operational at NOAA’s National Centers for Environmental Prediction (NCEP) use the Thompson et al. mixed-phase bulk cloud microphysics scheme. This scheme permits predicted surface precipitation to simultaneously consist of rain, snow, and graupel at the same location under c...
Institution National Oceanic and Atmospheric Administration - NOAA
Because of limitations of variational and ensemble data assimilation schemes, resulting analysis fields exhibit some noise from imbalance in subsequent model forecasts. Controlling finescale noise is desirable in the NOAA’s Rapid Refresh (RAP) assimilation/forecast system, which uses an hourly data assimilation cycle. Hence, a digital filter ini...
Institution National Oceanic and Atmospheric Administration - NOAA
The land surface model (LSM) described in this manuscript was originally developed as part of the NOAA Rapid Update Cycle (RUC) model development effort; with ongoing modifications, it is now used as an option for the WRF community model. The RUC model and its WRF-based NOAA successor, the Rapid Refresh (RAP), are hourly updated and have an emph...
Institution National Oceanic and Atmospheric Administration - NOAA
An operational upgrade of the RAP and HRRR model systems at NCEP is planned for August 2016. This coordinated upgrade (RAP version 3 and HRRR version 2, RAPv3/HRRRv2) includes many enhancements to the data assimilation, model, and post-processing formulations that result in significant improvements to nearly all forecast aspects, including uppe...
Institution National Oceanic and Atmospheric Administration - NOAA
The Mesoscale Predictability Experiment (MPEX)
The Mesoscale Predictability Experiment (MPEX) was conducted from 15 May to 15 June 2013 in the central United States. MPEX was motivated by the basic question of whether experimental, subsynoptic observations can extend convective-scale predictability and otherwise enhance skill in short-term regional numerical weather prediction. Observatio...
Institutions Earth System Research Laboratory - ESRL National Center for Atmospheric Research - NCAR National Oceanic and Atmospheric Administration - NOAA
The High-Resolution Rapid Refresh (HRRR) is a convection-allowing implementation of the Weather Research and Forecasting model (WRF-ARW) with hourly data assimilation that covers the conterminous United States and Alaska and runs in real time at the NOAA National Centers for Environmental Prediction. Implemented operationally at NOAA/NCEP in 201...
Institution National Oceanic and Atmospheric Administration - NOAA
The High-Resolution Rapid Refresh (HRRR) is a convection-allowing implementation of the Advanced Weather Research and Forecast model (WRF-ARW) that covers the conterminous United States and Alaska and runs hourly (for CONUS; every three hours for Alaska) in real time at the National Centers for Environmental Prediction. The high-resolution forec...
Institution National Oceanic and Atmospheric Administration - NOAA
A Case Study Investigating the Low Summertime CAPE Behavior in the Global Forecast System
Convective available potential energy (CAPE) is an important index for storm forecasting. Recent versions (v15.2 and v16) of the Global Forecast System (GFS) predict lower values of CAPE during summertime in the continental United States than analysis and observation. We conducted an evaluation of the GFS in simulating summertime CAPE using an e...
Institution National Oceanic and Atmospheric Administration - NOAA
The Marshall Fire on 30 December 2021 became the most destructive wildfire costwise in Colorado history as it evolved into a suburban firestorm in southeastern Boulder County, driven by strong winds and a snow-free and drought-influenced fuel state. The fire was driven by a strong downslope windstorm that maintained its intensity for nearly 11 h...
Institution National Oceanic and Atmospheric Administration - NOAA