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Lori Drake

1. Introduction Warning members of the public about impending tropical cyclone (TC) threats to their communities necessarily involves the communication of TC descriptions and forecasts, and their associated uncertainties, based in science, to audiences composed primarily of nonscientists. Since the data cannot be communicated in raw form outside the discipline, what is actually disseminated is information about what meteorologists know—and what they do not know—about the current and projected

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Brian J. Etherton

1. Introduction Incorrect weather forecasts cause problems ranging from mere inconvenience to significant loss of life and property. Computer model forecasts, also referred to as guidance, are a valuable tool used by weather forecasters. Predictions by forecast agencies should improve if the accuracy of computer model guidance is increased. In addition to improving accuracy, producing guidance of similar accuracy but in less time is also beneficial to forecasters, as it would allow users of

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Staff Members Weather Forecasting Research Center, University of Chicago

STAFFMEMBERS, UNIVERSITY OF CHICAGO42 1OCTOBER 1956AEXPERIME iT IN FORECASTING THE DISPLACEMENT OF500-MILLIBAR TROUGHS AND RIDGESBy Sta$ Members, Weather Forecasting Research Center, University of Chicago University of Chicago' (Manuscript received 5 December 1955)ABSTRACTA number of simple objective methods of computing the motion of troughs and ridges at the 500-mb levelwere tested for a fifty-day period, with use of data over and near North America. The most

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Fumin Ren, Chenchen Ding, Da-Lin Zhang, Deliang Chen, Hong-li Ren, and Wenyu Qiu

1. Introduction Considerable progress has been made in numerical weather prediction (NWP) during the past decades due partly to a steady accumulation of scientific knowledge and partly to technological advances in utilizing a variety of observations and gaining computing power ( Bauer et al. 2015 ). Despite the steady progress, significant forecast errors in today’s NWP models are still present, especially in processing atmospheric statistical properties that are not directly available from the

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Mark J. Rodwell and Francisco J. Doblas-Reyes

) based on the 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40) record ( Uppala et al. 2005 ). The much higher daily observed values for summer 2003 are shown by the dotted curve. Horizontal dashed and dotted lines show the corresponding weekly mean and monthly mean values. Important questions are how well was this 2003 event “predicted,” and what impact did the predictions have on decision making? The solid black curve shows a single high-resolution forecast

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Clark Evans, Donald F. Van Dyke, and Todd Lericos

1. Introduction Meteorological ensembles owe substantial motivation to the findings of Lorenz (1963) , who demonstrated that a small change in the initial representation of the atmospheric state can result in comparatively large forecast differences between any two otherwise identical forecasts. Though the precise methods of doing so vary from one ensemble prediction system to another, modern ensembles attempt to quantify part or all of the range of plausible forecast outcomes that may be

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Thomas C. Pagano, Andrew W. Wood, Maria-Helena Ramos, Hannah L. Cloke, Florian Pappenberger, Martyn P. Clark, Michael Cranston, Dmitri Kavetski, Thibault Mathevet, Soroosh Sorooshian, and Jan S. Verkade

1. Introduction Recent water-related disasters have captured public attention and led to increased interest in hydrologic forecasting systems. Flooding was responsible for nearly half of all natural catastrophe-related losses in 2013, with floods in Europe, Asia, Canada, the United States, and Australia causing over $20 billion (U.S. dollars) in losses [see and Coffman (2013) ]. The human toll in developing

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Chermelle Engel and Elizabeth E. Ebert

1. Introduction Public weather forecast practices change with the quality and amount of information and tools available. In Australia, public weather forecasts have evolved over the decades from short-term forecasts (around 24 h ahead), based on locally observed information ( Persson 2005 ; Persson and Grazzini 2007 ), to forecasts with lead times out to 8 days, which are strongly guided by numerical weather prediction (NWP) model forecasts. As NWP models improve, public weather forecasting

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William S. Lamberson, Ryan D. Torn, Lance F. Bosart, and Linus Magnusson

1. Introduction The last 30 years have been characterized by a significant improvement in the quality of medium-range (3–10 day) forecasts of midlatitude weather systems. Presently, 6-day forecasts issued by the European Centre for Medium-Range Weather Forecasts (ECMWF) for the Northern Hemisphere extratropics are as accurate as 5-day forecasts issued in the early 2000s, 4-day forecasts issued in the mid-1990s, and 3-day forecasts issued in the early 1980s ( Richardson et al. 2013 ). These

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David R. Novak, Christopher Bailey, Keith F. Brill, Patrick Burke, Wallace A. Hogsett, Robert Rausch, and Michael Schichtel

1. Introduction As the skill of numerical weather prediction (NWP) and associated postprocessed guidance continues to improve, recent debate asks to what degree can human forecasters add quality 1 to NWP (e.g., Mass 2003 ; Bosart 2003 ; Roebber et al. 2004 ; Reynolds 2003 ; Doswell 2004 ; Stuart et al. 2006 , 2007 ; Homar et al. 2006 ; Novak et al. 2008 ; Ruth et al. 2009 ). The National Centers for Environmental Prediction’s (NCEP) Weather Prediction Center (WPC 2 ) has a broad

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