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Long-range weather forecasts by Dr David Stephens

Posted by Mecardo on 1 February 2017

Since 2001, Long-range weather forecasts were issued by the Department of Agriculture, Western Australia (DAFWA) and the Australian Export Grains Innovation Centre (AEGIC) by Dr David Stephens.

Dr Stephens has a reputation for producing the most accurate weather and crop yield forecasts in Australia, and has agreed to write occasional articles on Mecardo to help provide weather insights to our readers.

Examples of key forecasts in relation to the total Murray-Darling Dam Storage are shown in Figure 1.

These forecasts are based on an ENSO Sequence System (ESS) that picks analogue years (similar years in the past to the present) in broad-scale indicators related to ENSO (El Niño-Southern Oscillation). Major changes in storage followed these forecasts in the way that was expected, except for the anomalous 2007 La Niña which had a positive Indian Ocean Dipole (none of the models predicted). 


Weather chart.pngFigure 1: Total Murray Darling Dam Storage as a percentage full versus key DAFWA/AEGIC forecasts (red arrow – dry; blue arrow -wet).

Hind-cast comparison with forecasts from a year ago

A year ago, the “top 5” ranked analogue years showed a distinct shift towards above average rainfall in the winter growing season. There was a high level of confidence in this forecast since it was the year after El Niño and there was a convergence in rainfall prospects. Generally, rainfall was wetter than expected in eastern Australia (due to strong negative Indian Ocean dipole event forming mid-year) and drier than expected in Western Australia due to moisture being consistently being drawn down over eastern Australia. However, excellent seeding rains in WA between March to May compensated to a degree for the drier finish.
Weather chart1.png

Table 1: January 2016 Analogue years and rainfall – High level of confidence (Comparison with forecast from the same time last year). Actual Rainfall listed was for May-October.

For this year, there are a number of global and local indicators that suggest it will not be as wet in 2017 as 2016. There also appears to be a lower chance of a major frost event in Western Australia. Agrometeorology Australia has now released it preliminary forecast for the Australian 2017 winter growing season and subscribers will get a full summary of global and local indicators along with the top ranked analogue years. State and national wheat production forecasts will also be issued.

Dr David Stephens provides a wide range of services through his newly established business: AgroMeteorology Australia (AMA). The services are detailed below, and if you are interested in further insight for strategic planning purposes we recommend visiting the AMA website, or contacting David on david.stephens@agromet.com.au

AGROMET SERVICES.pngClick here to visit AgroMeteorology Australia

 

Topics: weather

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