Event Presentation: Weather forecasting: It's the BOM

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The systems behind weather forecasting have changed enormously with the introduction of many new technologies but we still produce forecasts similar to those at the start of the 20th century. SA is on …

The systems behind weather forecasting have changed enormously with the introduction of many new technologies but we still produce forecasts similar to those at the start of the 20th century. SA is on the verge of a new breakthrough which will bring forecasts into the 21st century.

Forecasters at the Bureau of Meteorology (BoM) recently underwent training in the Next Generation Forecast and Warning System (NexGenFWS). The new system allows meteorologists to produce forecasts for temperature, rains, winds, humidity and more, and will include graphical, map-based representations. Probability forecasting will also be introduced with the new system.

Our host, Network Ten’s Jane Reilly, and experts from the BoM—Paul Lainio and Duncan Tippins—discussed the new highs for predicting SA’s weather.

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  • Introduction; self introduction of panel Jane Reilly, Duncan Tippins and Paul Lainio Introduction of session; This session guides the audience through the major steps which occurred leading to the way in which the Bureau in SA forecasts today. Question 1/ How long have people forecast the weather? Answer 1/ Forever. People have always observed the weather to determine their activities. For instance; when planning hunting activities early people would have delayed venturing outside if there was a thunderstorm approaching. Q2/ What was the first big step toward modern meteorology? A2/ The development of methods to measure/describe the atmosphere/weather. Systematic measurement helped people to get a shared understanding of the weather. Measurements meant the description of the weather was no longer subject to a personal interpretation. Wind Vane Tower of Winds Athens 2BC 15’th century Cardinal Nicholas deCusa hygrometer 16’th century thermometer – many contributors (currently 2 scales celicius and farenheit) 1643 Torricelli – barometer.
  • Crimean War Oct 1853 to Feb 1856. Russian Empire versus alliance of French, British, Ottoman Empire and Kingdom of Sardina. Nov 14-16 1854. Naval disaster in Crimean war . 1 French warship, 38 merchant vessels destroyed by storm. Storm path was reconstructed and demonstrated real time synoptic maps could have given commanders 1 day to prepare. As a result a National Storm Warning service set up in France. Q/ What technological development was needed to achieve this first forecasting service? A/ This next big step in meteorology required a rapid means of communication. Morse Code. Invented 1830’s to 1840’s. Meant weather observations could be taken simultaneously and a snapshot of the weather (synoptic chart). These could be sequenced to track the motion and evolution of weather patterns and then linearly pushed forward in time to produce a forecast.
  • There are about 10,000 surface weather observations across the world. Density of observations varies significantly because; Prosperity Communication Transport International aid Costs about $10,000/year to run an Automatic Weather Station. Many data sparse areas. Q/ What was the breakthrough (BIG STEP) forward in meteorology that helped fill in the gaps. A/ Weather satellite. 1960 Tiros 1. Now MTSAT 1R Japanese satellite covers Australia and this hemisphere. Part of a series of geostationary satellites across the globe. Also Radar developed during WWII Q/ What other ways do we observe the weather? A/ Weather balloons, aircraft, ships, radar profiler etc. Billions of dollars invested but by using observations we can only forecast 24 hours. We use Models to forecast beyond Day1.
  • Morse Code developed 1830’s-1840’s. 1872 Overland telegraph Australia. Postulated west to east travel of weather. April 1881. Inter-colonial meeting established data standards and sharing and use of isobaric maps. The Government Astronomers believed: “ Isobaric maps are the best way of conveying to the public the passage of barometric depressions “ First SA Forecast in 1888. Broad forecast but in some ways quite similar to the way in which forecasts are created today. All states ran their own Weather Offices and it wasn’t until 1908 that the Commonwealth BoM was created resulting in clear standards nationally for observing the weather and creating forecasts from the same base. Q/ What is celebrated on 23 March each year? A/ International Meteorological Organisation created in 1873. Replaced by World Meteorological Organisation decreed by convention on 23 March 1950 and started 1951.
  • Introduction; self introduction of panel Jane Reilly, Duncan Tippins and Paul Lainio Introduction of session; This session guides the audience through the major steps which occurred leading to the way in which the Bureau in SA forecasts today. Question 1/ How long have people forecast the weather? Answer 1/ Forever. People have always observed the weather to determine their activities. For instance; when planning hunting activities early people would have delayed venturing outside if there was a thunderstorm approaching. Q2/ What was the first big step toward modern meteorology? A2/ The development of methods to measure/describe the atmosphere/weather. Systematic measurement helped people to get a shared understanding of the weather. Measurements meant the description of the weather was no longer subject to a personal interpretation. Wind Vane Tower of Winds Athens 2BC 15’th century Cardinal Nicholas deCusa hygrometer 16’th century thermometer – many contributors (currently 2 scales celicius and farenheit) 1643 Torricelli – barometer.
  • The chart should look something like this. You will note the exercise has quite a few observations over ocean areas to the south of Australia. On a real weather chart there are very few observations in these parts. Meteorologists use the few observations they have in combination with satellite interpretation.
  • Models are developed independently and they use maths and physics equations to simulate the atmosphere. Different equations can be used depending on State of the science in that country Power of supercomputers Ability to ingest different types of observations Means that the output can vary considerably especially at days 5, 6, 7 and especially during rapidly changing weather situations. Meteorologists must understand the long term skill of the model, bias, internal consistency and compare against other models to acieve the best forecast possible.
  • As above
  • By editing the weather elements 3 hourly for 3 days then 6 hourly to 7 days the weather is described across the state.
  • Multiple ‘official’ forecast outputs are possible
  • Massive database. Can be accepted by external clients and put direct into geospatial data systems. This can assist with better planning and operations as weather data can be viewed in concert with any other data the client has (eg CFS unit locations).
  • Working out what is relevant and important is easy for a person but GFE uses rules.
  • There can be quite marked differences between a location forecast and an area forecast.
  • Answer is 1 and 2 (previous slide)
  • This is the text produced automatically.
  • The NexGenFWS can provide information to explain the probability and likely amount of rainfall.
  • It is easy to read the rainfall probability and the Rainfall amount together. However, these are entirely separate components. We have seen that rainfall probability is for >0.2mm. Rainfall amount is the 25% to 50% chance of receiving rainfall. It gives the likely amount of rain. The calculation indicates the amount that at least 50% of people will receive.
  • Forecasters are presented with a forecast map for temperature across SA for tomorrow. Forecasters then adjust that map based on all the knowledge they have available. This includes weather station data, satellite and radar information. It also includes a range of computer models for which the forecasters understand the strengths, weakness and bias’ of the data. The adjusted data then becomes the temperature forecast for tomorrow. Forecast maps are then adjusted for days 2 – 7. Forecast maps are then adjusted for Rainfall, Winds, Humidity etc. When all this is completed each location across the state has 7 days of information about temperature, rain, winds, humidity etc. In other words all locations have a 7-day forecast.
  • Note that output is available every 3 hours for 3 days for most weather parameters and every 6 hours for the remaining time to 7 days.
  • The Forecast Explorer is likely to be upgraded during 2011/2012 so it will be able to display observations and forecasts. It will be zoomable, you will be able to pan and it will work much like Google Maps.

Transcript

  • 1. Weather Forecasting It’s the BoM From the past to the future of weather forecasting. Paul Lainio and Duncan Tippins, Bureau of Meteorology, SA Jane Reilly, Channel 10
  • 2. Forecasting What’s the link with the Crimean War?
  • 3. Worldwide Weather Observations
  • 4. First Published SA Forecast. 15 Nov 1888
  • 5. Drawing Weather Charts
    • Q1/ Which way does the air rotate around a low pressure cell?
    • Clockwise
    • Anticlockwise
    10
  • 6. Which way does the air rotate around a low pressure cell?
  • 7. Drawing Weather Charts
    • Q2/ Is the air rising or falling in a high pressure cell?
    • Rising
    • Falling
    10
  • 8. Is the air rising or falling in a high pressure cell?
  • 9. Drawing Weather Charts
    • Q3/ An isobar is
    • A place where meteorologists drink
    • A line of equal pressure
    • A line of equal temperature
    • A contour of topography
    10
  • 10. An isobar is…
  • 11. Drawing Weather Charts
    • Q4/ A weather map is also called
    • Isobaric map
    • Synoptic chart
    • Mean sea level pressure analysis
    • All of the above
    10
  • 12. A weather map is also called
  • 13.
    • INTERMISSION
  • 14. Weather Forecasting It’s the BoM From the past to the future of weather forecasting. Paul Lainio and Duncan Tippins, Bureau of Meteorology, SA Jane Reilly, Channel 10
  • 15. My Answer
  • 16. Using Models in Forecasting
  • 17. Using Models in Forecasting Jane Reilly – maybe not the weather forecasting model I was think of!
  • 18. Models are not perfect 7-Day Forecast for Sun 25 July 2004 Australian Computer Model European Computer Model
  • 19. End Product How can we do better?
  • 20. The Next Generation Forecast and Warning System (NexGen)
    • Graphical Forecast Editor (GFE)
    • Developed in US for National Weather Service – modified for Australia by BoM
    • Pilot project in Victoria 2008
    • NSW September 2010
    • TAS June 2011
    • SA October 2011
  • 21. About The System
    • Forecasters edit grids (maps) of many weather elements
  • 22. Forecasting under GFE Forecaster
  • 23. The Australian Digital Forecast Database Spatial Resolution 6km Weather Elements Temperature Wind speed/Direction Rainfall totals Weather type Temporal Resolution 3 hourly to 72 hours 6 hourly to 7 days Available to external providers
  • 24. Although it’s automated it’s not easy – North West Pastoral What is the wind phrase?
  • 25.
    • What is your forecast?
    • Winds light and variable southeast of Woomera. Elsewhere east to northeast winds 5 to 15km/h reaching up to 30km/h late morning then tending light and variable late afternoon.
    • Northeast to southeasterly averaging 10 to 20 km/h becoming light during the afternoon.
    • Northeast winds reaching up to 30km/h at times in the morning.
    It’s not easy – North West Pastoral 10am 4pm 1pm 7am 10
  • 26. What is your forecast?
  • 27. What’s happening – Districts versus towns Eastern Eyre Peninsula Forecast Partly cloudy Cleve Forecast
  • 28. Your forecast – Districts versus towns Remember 10% of an area needs to be affected for the text to appear in the forecast.
    • What is your forecast for
    • Woomera?
    • Fine
    • Partly cloudy
    • Isolated showers
    10
  • 29. Your forecast – Districts versus towns Remember 10% of an area needs to be affected for the text to appear in the forecast
    • What is your forecast for
    • The Northwest Pastoral?
    • Fine
    • Isolated showers
    • Isolated showers in the east
    10
  • 30. What is your forecast?
  • 31. Actual Forecast Northwest Pastoral: Sunny morning. Isolated showers east of Stuart Highway in the afternoon and evening. Woomera: Sunny Local effect area; East or West of the Stuart Highway
  • 32. To Warn or not to Warn!
    • Issue Warning?
    • Spencer Gulf and Gulf St Vincent
    • Spencer Gulf
    • Gulf St Vincent
    • No warning
    Remember 10% of an area needs to be affected to result in a warning 10
  • 33. Would you issue a warning?
  • 34. The Warning Forecast for Wednesday 16 Nov: Strong wind warning for Wednesday for Spencer Gulf: Southeasterly 10 to 15 knots tending south to southeasterly 15 to 20 knots around midday. Winds north of Cowell to Wallaroo reaching 20 to 30 knots late afternoon and early evening.
  • 35.
    • Q/ Will it rain?
    • A/ Probability of precipitation
    • Q/ How much rain is expected?
    • A1/Likely Rainfall
    • and
    • A2/ Possible higher rainfall
    • Q/ When will it rain?
    • A/ Weather
    Grid/Forecast Explorer Answers
  • 36. Metropolitan Forecast
    • City Forecast
    • Includes a day 1 forecast of the probability of any measurable rain
    • Includes a forecast of the likely rainfall range at a city location.
    • Relates directly to the Kent Town location as a proxy for a city site.
    Very useful but treat carefully
  • 37. How do we determine the chance of rain? Let’s focus on Adelaide 4:30 pm – 7:30 pm grid
  • 38. How do we determine the chance of rain? Let’s focus on Adelaide 7:30 pm – 10:30 pm grid
  • 39.
    • Chance of any rain at Adelaide?
    • 10%
    • 20%
    • 30%
    10:30 pm – 1:30 am grid Let’s focus on Adelaide How do we determine the chance of rain? 10
  • 40. Chance of any rain at Adelaide?
  • 41. What did the official forecast have?
  • 42. What is the relationship between “Chance of Rain” and “Rainfall Amount”
    • The “rainfall amount” uses the 50 th and 25 th percentiles.
    • Why?
    • 1) Because we can!
    • 2) To confuse the public!
    • 3) All of the above!
  • 43.
    • The real answer is to try to provide the public with “useful” information.
    • Most of the rainfall variation is at low rainfall probabilities (or high rainfall amounts).
    • So the forecasts describe a rainfall
    • range biased towards lower rainfall
    • probabilities (50 th to 25 th percentiles)
    What is the relationship between “Chance of Rain” and “Rainfall Amount”
  • 44. The Future - Public Graphics
  • 45. SA Timeline
    • 26 October 2011: Implemented new system
    • Autumn 2012: Graphical forecasts and more locations