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Steven E. Koch authored and/or contributed to the following articles/publications.
Facilitating Transition between Research and Operation in Numerical Weather Prediction
The DTC Ensemble Testbed: A New Testing and Evaluation Facility for Mesoscale Ensembles
As operational centers move towards ensemble-based probabilistic forecasting, the Developmental Testbed Center (DTC) has been asked to expand its efforts by providing a testbed platform to serve as a bridge between research and operations. Hence, the DTC has established the DTC Ensemble Testbed (DET). The goal of DET is to provide an environment...
Unmanned Aerial Systems (UAS) data are the first future observation system to be evaluated by NOAA using the newly developed global Observing System Simulation Experiment (OSSE) system. Based on years of effort, the OSSE system has been calibrated by comparing observation impact in the Gridpoint Statistical Interpolation/Global Forecast System (...
HWRF is a specialized version of the WRF model that has been designed to simulate and predict tropical cyclones. It was developed at EMC/NCEP based upon WRF version 2.0 and became operational for the 2007 hurricane season. During its development, numerous features were implemented to improve performance. However most of these advances are not av...
Calibration of Synthetic Observations for a Joint Observing System Simulation Experiment
A cooperative effort between agencies including the National Centers for Environmental Prediction (NCEP), Earth System Research Laboratory (ESRL), European Centre for Medium-range Weather Forecasting (ECMWF), National Astronautics and Space Administration (NASA), and National Environmental Satellite, Data, and Information Service (NESDIS) is und...
The Process of Thunderstorm Generation by Bores
The relative importance for thunderstorm initiation of direct lifting of conditionally unstable air by bores compared to the upward mixing of low-level moisture by bore circulations is examined. A large number of lidar and radar profiling systems are used in this effort, in conjunction with ultra-high resolution numerical models. Profiling instr...
The Meteorological Assimilation Data Ingest System (MADIS) has been in development for 6 years at the NOAA/OAR/ERSL Global Systems Division in Boulder, Colorado. During this time, the MADIS has become the largest surface and upper-air observing data portal in the world, aggregating over 40,000 stations and 150 networks with hundreds of end-users...
Lidar-radar analyses of convection initiation by gravity currents, bores, and solitons
Gravity currents, bores, and solitary wave trains (solitons) observed in several cases by a large variety of ground-based and airborne profiling systems and also numerically simulated with an ultra-high resolution numerical model are collectively used to understand the convection initiation process. Lidar instrumentation includes moisture measur...
Observing System Simulation Experiments for Unmanned Aircraft Systems: preliminary efforts
Unmanned Aircraft Systems (UAS) are a developing technology which have the potential to provide unique observations of the atmosphere within the coming decade. These aircraft can be deployed in remote data poor locations to complement existing satellite and conventional observations. An Observing System Simulation Experiment (OSSE) is undertake...
Spectral and structure function analyses of horizontal velocity fields observed in the upper troposphere and lower stratosphere during the Severe Clear Air Turbulence Collides with Air Traffic (SCATCAT) field program, conducted over the Pacific, were carried out in an effort to identify the scale interactions of turbulence and small-scale gravit...
The most significant precipitation events in California occur during the winter and are often related to synoptic-scale storms from the Pacific Ocean. Because of the terrain characteristics and the fact that the urban and infrastructural expansion is concentrated in lower elevation areas of the California Central Valley, a high risk of flooding...
To assist in optimizing a mixed-physics ensemble for warm season mesoscale convective system rainfall forecasting, the impact of various physical schemes as well as their interactions on rainfall when different initializations were used has been investigated. For this purpose, high-resolution Weather Research and Forecasting (WRF) model simulat...
Experimental Forecasts of Mountain Waves for the Terrain-Induced ROTOR Experiment (T-REX)
The main objective of the Terrain-Induced Rotor Experiment (T-REX) is to understand the nature of the coupling of mountain-induced rotor circulations to the structure and evolution of overlying mountain waves and to the underlying boundary layer (Grubisic et al. 2004). T-REX results also aim at increasing the understanding of mountain wave dynam...
Evaluation of the NCEP WRF NMM and ARW models for some recent high-impact weather events
At the last Weather Analysis and Forecasting/Numerical Weather Prediction Conference in Washington, D.C. in the summer of 2005, a number of presentations were made (Session 7) on the Developmental Testbed Center (DTC) Winter Forecast Experiment (DWFE), conducted during the winter of 2005. The goal of that experiment was to run and evaluate two v...
Turbulence in MCS anvils: Observations and analyses from BAMEX
The occurrence of large mesoscale convective systems (MCSs) during the warm season over much of the central United States presents a hazard to aviation that has not been thoroughly assessed. In addition to lightning and hail, the extensive mid- to upper-level anvil clouds that form in these systems can cause severe turbulence. Although avoidance...
Model development and enhancement PDT
For purposes of flight planning and routing, it is necessary to provide accurate and useful forecasts of aviation weather hazards. This requires a combination of improved model guidance and development of algorithms to convert from atmospheric “state variables” (temperature, winds, pressure, humidity, precipitation types) predicted directly from...
Clear-air turbulence (CAT) is frequently observed in the vicinity of upper-level jet streaks. Such turbulence generation coincides with the occurrence of gravity waves at approximately the same location ? on the northeast side of the jet exit region. These observations point to a possible chain-reaction relationship between an upper-level jet, g...
In recent years, a mixed-physics ensemble approach has been investigated as a method to better predict mesoscale convective system ( MCS) rainfall. For both mixed-physics ensemble design and interpretation, knowledge of the general impact of various physical schemes and their interactions on warm season MCS rainfall forecasts would...
The developmental testbed center winter forecasting experiment
The Developmental Testbed Center (DTC – Nance et al. 2005) was established so the Numerical Weather Prediction (NWP) research and operational communities can interact to accelerate testing and evaluation of new models and techniques for research applications and operational implementation. One method of testing and evaluation employed by the DTC...
Quantitative Precipitation Forecast (QPF)verification of DWFE
Assessing the quality of quantitative precipitation forecasts from numerical weather prediction models has been accomplished by either comparing a precipitation forecast grid to observation stations or to an analysed gridded field of precipitation. If the aim for evaluating precipitation forecasts is to asses the accuracy of the forecast at cert...
Supplement to the Value of Wind Profiler Data in U.S. Weather Forecasting
An assessment of the value of data from the NOAA Profiler Network (NPN) on weather forecasting is presented. A series of experiments using the Rapid Update Cycle (RUC) model in which various data sources were denied from RUC were conducted to assess the relative importance of the profiler data for short-range wind forecasts. Average verification...
The value of wind profiler data in US weather forecasting
An assessment of the value of data from the NOAA Profiler Network (NPN) on weather forecasting is presented. A series of experiments was conducted using the Rapid Update Cycle (RUC) model/assimilation system in which various data sources were denied in order to assess the relative importance of the profiler data for short-range wind ...
The impact of a split-front rainband on Appalachian cold-air damming erosion
An overview of the International H2O Project (IHOP_2002) and some preliminary highlights
The International H2O Project (IHOP_2002) is one of the largest North American meteorological field experiments in history. From 13 May to 25 June 2002, over 250 researchers and technical staff from the United States, Germany, France, and Canada converged on the Southern Great Plains to measure water vapor and other atmospheric variab...
AN INVESTIGATION OF IHOP CONVECTIVE SYSTEM PREDICTABILITY USING A MATRIX OF 19 WRF MEMBERS
MULTISCALE ANALYSES OF MOISTURE TRANSPORT BY THE CENTRAL PLAINS LOWLEVEL JET DURING IHOP
An analysis of the impact of a split-front rainband on Appalachian cold-air damming
Appalachian cold-air damming (CAD) is characterized by the development of a cool, stable air mass that is advected southwestward along the eastern slopes of the Appalachian Mountains by low-level ageostrophic flow. Operational forecasters have identified the demise of CAD as a major forecasting challenge, in part because numerical weather predi...
Numerical simulations of a large-amplitude mesoscale gravity wave event
Numerical simulations with the NCAR/PSU Mesoscale Model 5 (MM5) were performed to study a large-amplitude gravity wave event that occurred on 4 January 1994 along the East Coast of the United States. Results from the MM5 control simulation using a 12-km mesh resolution compared well with the synoptic and mesoscale observational analysis. The si...
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The map room: A Structured Process for Prediction of Convection Associated with Split Cold Fronts
THE LIFE CYCLE OF A BORE EVENT OVER THE US SOUTHERN GREAT PLAINS DURING IHOP _2002
The impact of wind profiler data on short-range RUC model forecasts
ANALYSIS OF MESOSCALE VERTICAL CIRCULATIONS USING WSR-88D VAD AND WIND PROFILER DATA
IMPROVING MESOSCALE ANALYSIS AND PREDICTION USING WIND PROFILER DATA
A STRUCTURED PROCESS FOR PREDICTION OF CONVECTION ASSOCIATED WITH SPLIT COLD FRONTS
Predicting Clear-Air Turbulence from Diagnosis of Unbalanced Flow
Detailed diagnostic analyses are performed upon a mesoscale numerical simulation of a well-observed gravity-wave event that occurred on 4 January 1994 along the East Coast of the United States. The value of using wavelet analysis to investigate the evolving gravity-wave structure and of using potential vorticity (PV) inversion to study the nat...
Real-time detection of split fronts using mesoscale models and WSR-88D radar products
A structured methodology for detecting the presence of split cold fronts in an operational forecast environment is developed and applied to a case in which a split front passed over a region of cold air damming in the southeastern United States. A real-time mesoscale model and various products from the WSR-88D-including the velocity-azimuth dis...
Extraction of geopotential height and temperature structure from profiler and rawinsonde winds
Mesoscale height and temperature fields can be extracted from the observed wind field by making use of the full divergence equation. Mass changes associated with irrotational ageostrophic motions are retained for a nearly complete description of the height field. Above the boundary layer, in the absence of friction, the divergence equation incl...
The role of dual cold fronts aloft in a major tornado and flash flooding event
An automated system for the analysis of gravity waves and other mesoscale phenomena
An automated near-real-time system for the surface analysis of gravity waves and other mesoscale phenomena is developed, tested, and applied to several cases. Five-minute observations from the Automated Surface Observing System (ASOS) network provide the primary source of data for the mesoanalysis system. ASOS time series data are downloaded, ...
Mesoscale model simulations have been performed of the second episode of gravity waves observed in great detail in previous studies on 11-12 July 1981 during the Cooperative Convective Precipitation Experiment. The dominant wave simulated by the model was mechanically forced by the strong updraft associated with a mountain-plains solenoid (MPS)...
BALANCED INITIALIZATION PROCEDURES AND MESOSCALE PREDICTABILITY
MCS DEVELOPMENT WITHIN CONTINENTAL-SCALE ELONGATED DRY FILAMENTS IN GOES WATER VAPOR IMAGES
The life cycle of a mesoscale gravity wave as observed by a network of Doppler wind profilers
The generation of propagating gravity waves by a mountain-plains solenoid (MPS)
A survey of unbalanced flow diagnostics and their application
This paper presents an extensive survey of the most commonly used tools for diagnosing unbalanced flow in the atmosphere, namely the Lagrangian Rossby number, Psi vector, divergence equation, nonlinear balance equation, generalized omega-equation, and departure from fields obtained by potential vorticity (PV) inversion. The basic theory, assump...
The generation of propagating gravity wave by an orographic density current
Convective storm nowcasting using the Space-Time Meso Analysis System
The detection of narrow zones of low-level convergence (or boundaries) critically important for thunderstorm initiation, development and evolution are primary objectives of automated nowcasting systems. The Space-Time Meso Analysis System (STMAS) has been developed at the NOAA Earth System Research Laboratory to take full advantage of the nearly...
Rapid Mesoscale Environmental Changes Accompanying Genesis of an Unusual Tornado
This study documents a very rapid increase in convective instability, vertical wind shear, and mesoscale forcing leading to the formation of a highly unusual tornado as detected by a ground-based microwave radiometer and wind profiler, and in 1-km resolution mesoanalyses. Mesoscale forcing for the rapid development of severe convection began wit...
Institutions National Center for Atmospheric Research - NCAR National Oceanic and Atmospheric Administration - NOAA