A Brief History of Weather Forecasting. The Stone Age Prior to approximately 1955, forecasting was basically a subjective art, and not very skillful.

Slides:



Advertisements
Similar presentations
Chapter 13 Weather Forecasting.
Advertisements

Chapter 13 – Weather Analysis and Forecasting
PRESENTS: FORECASTING FOR OPERATIONS AND DESIGN February 16 th 2011 – Aberdeen.
SIPR Dundee. © Crown copyright Scottish Flood Forecasting Service Pete Buchanan – Met Office Richard Maxey – SEPA SIPR, Dundee, 21 June 2011.
Part 5. Human Activities Chapter 13 Weather Forecasting and Analysis.
1 Use of Mesoscale and Ensemble Modeling for Predicting Heavy Rainfall Events Dave Ondrejik Warning Coordination Meteorologist
2012: Hurricane Sandy 125 dead, 60+ billion dollars damage.
For the Lesson: Eta Characteristics, Biases, and Usage December 1998 ETA-32 MODEL CHARACTERISTICS.
SCIENCE NEWS Magnitude CENTRAL ITALY Magnitude CENTRAL ITALY.
A Compare and Contrast Study of Two Banded Snow Storms Part I – January 6 th, 2002.
The Future of Northwest Weather Prediction Cliff Mass University of Washington.
Description and Preliminary Evaluation of the Expanded UW S hort R ange E nsemble F orecast System Maj. Tony Eckel, USAF University of Washington Atmospheric.
Determining the Local Implications of Global Warming For Urban Precipitation and Flooding Clifford Mass and Eric Salathe, Richard Steed University of Washington.
Revolutions in Remote Sensing Greatly Enhanced Weather Prediction from the 1950s Through Today.
Introduction to Weather Forecasting Cliff Mass Department of Atmospheric Sciences University of Washington.
EG1204: Earth Systems: an introduction Meteorology and Climate Lecture 7 Climate: prediction & change.
Supplemental Topic Weather Analysis and Forecasting.
A History of Modern Weather Forecasting. The Stone Age Prior to approximately 1955, forecasting was basically a subjective art, and not very skillful.
A History of Modern Weather Forecasting
Forecasting Boot Camp. Major Steps in the Forecast Process Data Collection Quality Control Data Assimilation Model Integration Post Processing of Model.
Ensembles and Probabilistic Forecasting. Probabilistic Prediction Because of forecast uncertainties, predictions must be provided in a probabilistic framework,
A Brief History of Weather Forecasting. The Beginning: Weather Sayings "Red Sky at night, sailor's delight. Red sky in the morning, sailor take warning."
Chapter 13 – Weather Analysis and Forecasting. The National Weather Service The National Weather Service (NWS) is responsible for forecasts several times.
Weather Forecasting - II. Review The forecasting of weather by high-speed computers is known as numerical weather prediction. Mathematical models that.
Forecasting Boot Camp.
Forecasting and Numerical Weather Prediction (NWP) NOWcasting Description of atmospheric models Specific Models Types of variables and how to determine.
Lecture Oct 18. Today’s lecture Quiz returned on Monday –See Lis if you didn’t get yours –Quiz average 7.5 STD 2 Review from Monday –Calculate speed of.
Forecast Skill and Major Forecast Failures over the Northeastern Pacific and Western North America Lynn McMurdie and Cliff Mass University of Washington.
Toward a 4D Cube of the Atmosphere via Data Assimilation Kelvin Droegemeier University of Oklahoma 13 August 2009.
A History of Modern Weather Forecasting. The Beginning: Weather Sayings "Red Sky at night, sailor's delight. Red sky in the morning, sailor take warning."
Weather and Climate Prediction Cliff Mass University of Washington.
Chapter 9: Weather Forecasting Acquisition of weather information Acquisition of weather information Weather forecasting tools Weather forecasting tools.
Ensemble Forecasting and You The very basics Richard H. Grumm National Weather Service State College PA
You Can Avoid the Rain! Weather Tips for Biking. There are a number of approaches to dealing with rain.
Weather Forecasting Chapter 9 Dr. Craig Clements SJSU Met 10.
Chapter 9: Weather Forecasting Surface weather maps 500mb weather maps Satellite Images Radar Images.
A Brief History of Weather Forecasting The Beginning: Weather Sayings "Red Sky at night, sailor's delight. Red sky in the morning, sailor take warning."
Weather forecasting by computer Michael Revell NIWA
The Technology and Future of Weather Forecasting Cliff Mass University of Washington.
Weather Forecasting & Maps -Meteorologists make forecasts based on models that are produced by supercomputers which perform a large amount of calculations.
Ensembles and Probabilistic Prediction. Uncertainty in Forecasting All of the model forecasts I have talked about reflect a deterministic approach. This.
Forecasting the weather
Weather Forecasting Subtitle.
NWS MARINE PREDICTION CENTER America’s Weather Warning and Forecast Service for Mariners at Sea.
Figures from “The ECMWF Ensemble Prediction System”
You Can Avoid the Rain! Weather Tips for Biking. There are a number of approaches to dealing with this problem.
Chapter 13 – Weather Analysis and Forecasting. The National Weather Service The National Weather Service (NWS) is responsible for forecasts several times.
Forecasting Boot Camp.
2012: Hurricane Sandy 125 dead, 60+ billion dollars damage in an area with a population of tens of millions.
Numerical Weather Forecast Model (governing equations)
2012: Hurricane Sandy 125 dead, 60+ billion dollars damage in an area with a population of tens of millions.
Technology on the Cutting Edge of Weather Research and Forecasting
452 NWP 2015.
Update on the Northwest Regional Modeling System 2013
Overview of Deterministic Computer Models
Ensembles and Probabilistic Prediction
Winds and Forces Atmospheric Sciences 101.
How do models work? METR 2021: Spring 2009 Lab 10.
The art of weather forecasting
Probabilistic Prediction
What temporal averaging period is appropriate for MM5 verification?
The Stone Age Prior to approximately 1960, forecasting was basically a subjective art, and not very skillful. Observations were sparse, with only a few.
Weather Forecasts.
Update on the Northwest Regional Modeling System 2017
Challenge: High resolution models need high resolution observations
Upper Air Observations The atmosphere is 3D and can not be understood or forecast by using surface data alone ATM 101W2019.
The Technology and Future of Weather Forecasting ATMS 490
Cliff Mass and David Ovens University of Washington
Weather Forecasts.
Weather Forecasts.
Presentation transcript:

A Brief History of Weather Forecasting

The Stone Age Prior to approximately 1955, forecasting was basically a subjective art, and not very skillful. Observations were sparse, with only a few scattered ship reports over the oceans. The technology of forecasting was basically subjective extrapolation of weather systems using the upper level flow (the jet stream). Local weather details—which really weren’t understood-- were added subjectively.

Upper Level Chart

: The Advent of Modern Forecasting During this period, numerical weather prediction—forecasting future weather with digital computers-- became the key tool in the meteorologists tool bag. The launch of the first weather satellite (1960) gave meteorologists a view of the entire planet. Weather radars were placed around the U.S. explicitly showing areas of precipitation.

Numerical Weather Prediction The advent of digital computers in the late 1940s and early 1950’s made possible the simulation of atmospheric evolution numerically. The basic idea is if you understand the current state of the atmosphere, you can predict the future using the basic physical equations that describe the atmosphere.

Numerical Weather Prediction One such equation is Newton’s Second Law: F = ma Force = mass x acceleration Mass is the amount of matter Acceleration is how velocity changes with time Force is a push or pull on some object (e.g., gravitational force, pressure forces, friction) This equation is a time machine!

Using a wide range of weather observations we can create a three-dimensional description of the atmosphere… known as the initialization Numerical Weather Prediction

This gives the distribution of mass and allows us to calculate the various forces. Then… we can solve for the acceleration using F=ma But this gives us the future…. With the acceleration we can calculate the velocities in the future. Similar idea with temperature and humidity. Numerical Weather Prediction

These equations can be solved on a three- dimensional grid. As computer speed increased, the number of grid points could be increased. More (and thus) closer grid points means we can simulate (forecast) smaller and smaller scale features. We call this improved resolution.

A Steady Improvement Faster computers and better understanding of the atmosphere, allowed a better representation of important physical processes in the models More and more data became available for initialization As a result there has been a steady increase in forecast skill from 1960 to now.

Forecast Skill Improvement Forecast Error Year Better National Weather Service

Satellite and Weather Radars Give Us a More Comprehensive View of the Atmosphere

Camano Island Weather Radar

The computers models become capable of simulating/forecasting local weather. As the grid spacing decreased to 15 km and below… it became apparent that many of the local weather features could often be simulated and forecast by the models.

Forecaster at the Seattle National Weather Service Office The National Weather Service

But even with all this improving technology, some forecasts fail or are inadequate. Why?

Problems with the Models Some forecasts fail due to inadequacies in model physics…. How the model handles precipitation, friction, and other processes. Example: too much precipitation on mountain slopes Intensive work at the UW to address this problems.

Some forecasts fail due to poor initialization, i.e., a poor starting description of the atmosphere. This is particularly a problem for the Pacific Northwest, because we are downstream of a relatively data poor region…the Pacific Ocean.

Eta 48 hr SLP Forecast valid 00 UTC 3 March March 1999: Forecast a snowstorm … got a windstorm instead

Eta Model Sea Level Pressure: 12 UTC 2 March 99 Major Initialization Errors

Pacific Analysis At 4 PM 18 November 2003 Bad Observation

The problem of initialization should lessen as new observation technologies come on line and mature. New ways of using or assimilating the data are also being developed.

Seascan Unmanned Aircraft

There is a lack of detailed weather information immediately off the Northwest Coast. Major issue… lack of a coastal weather radar. The Northwest has the worst coastal weather radar coverage in the nation. Often can’t see the details of weather features before they make landfall. Seriously impacts short-term forecasts. Lack of Coastal Weather Information NWS Doppler Radar

NowWith Two New Radars

A More Fundamental Problem In a real sense, the way we have been forecasting is essentially flawed. The atmosphere is a chaotic system, in which small differences in the initialization…well within observational error… can have large impacts on the forecasts, particularly for longer forecasts. Not unlike a pinball game….

A More Fundamental Problem Thus, there is fundamental uncertainty in weather forecasts that can not be ignored. Similarly, uncertainty in our model physics also produces uncertainty in the forecasts. We should be using probabilities for all our forecasts or at least providing the range of possibilities. There is an approach to handling this issue that is being explored by the forecasting community…ensemble forecasts.

Ensemble Prediction Instead of making one forecast…make many…each with a slightly different initialization Possible to do now with the vastly greater computation resources that are available.

The Thanksgiving Forecast h forecast (valid Thu 10AM) 13: avn* 11: ngps* 12: cmcg* 10: tcwb* 9: ukmo* 8: eta* Verification 1: cent 7: avn 5: ngps 6: cmcg 4: tcwb 3: ukmo 2: eta - Reveals high uncertainty in storm track and intensity - Indicates low probability of Puget Sound wind event SLP and winds

Ensemble Prediction Can use ensembles to provide a new generation of products that give the probabilities that some weather feature will occur. Can also predict forecast skill! It appears that when forecasts are similar, forecast skill is higher. When forecasts differ greatly, forecast skill is less.

Ensemble-Based Probabilistic Products

Forecast Dissemination: The Achilles Heal Although the technology of weather prediction is rapidly improving, our ability to communicate what we know to the public is inadequate. Although the Internet and wireless communication provides—for the first time—the potential to distribute large amounts of weather information, we have not yet found an effective way to do so. The amount of information is massive, how do we distill and filter it for a wide variety of users? We are failing to communicate our degree of confidence in the forecasts.