Seasonal Climate Outlook Message for April to July 2003

The bottom line

SOI Remains Negative Dated 02/04/03

The 30day average of the SOI as of the 2nd April is minus 6.6. Based on the shift in monthly SOI value from the end of February (minus 9.3) to the end of March the SOI is in a "Consistently Negative" phase.

Despite the negative SOI value a somewhat mixed seasonal outlook across Queensland exists for April to June.

For the far north west and peninsular region of Queensland along with isolated pockets of the south east and south west the chance of getting above the long term April to June median rainfall has fallen to 20-40%. Rainfall probabilities across the rest of the state though have improved to 50-70%.

For example, there is an 80% chance of getting above the long term April to June median rainfall of 80mm at Emerald, a 73% chance of getting or getting above the April to June median rainfall of 91mm at Wandoan and a 67% chance of getting or getting above the April to June median rainfall of 133mm at Rockhampton.

As always when dealing with a probability based forecast system it is important to consider the alternate view. For example, currently there is an 80% chance of getting above 80mm at Emerald. This also means there is a 20% chance of not getting above 80mm.

Another way of looking at this is that in 8 years out of 10 (or slightly more than three quarters) with the current SOI pattern, Emerald has received more than 80mm for April to June. Therefore in 2 years out of 10 (or around one quarter) with the current SOI pattern, less than 80mm has been recorded at Emerald.

As rainfall probabilities and median rainfall levels vary throughout the year and from location to location, we strongly recommend referring to Australian Rainman for more specific rainfall data.

For those who like to follow historical patterns more closely, other years that have had a "Consistently Negative" SOI phase at the end of March include 1998, 93, 92, 87, 83, 78, 41, 26, 19, 15, 12, 06 and 1905. It can be very useful to find out what rainfall patterns and seasonal conditions where like during April to June in your area for those years.

For more specific climate information for your location refer to Australian Rainman, the latest "Climate Note" at www.dpi.qld.gov.au/climate or ring the DPI Call Centre on 13 25 23.

The full story

SOI Remains Negative Dated 02/04/03

The 30day average of the SOI as of the 2nd April is minus 6.6. Based on the shift in monthly SOI value from the end of February (minus 9.3) to the end of March the SOI is in a "Consistently Negative" phase.

Despite the negative SOI value a somewhat mixed seasonal outlook across Queensland exists for April to June.

For the far north west and peninsular region of Queensland along with isolated pockets of the south east and south west the chance of getting above the long term April to June median rainfall has fallen to 20-40%. Rainfall probabilities across the rest of the state though have improved to 50-70%.

For example, there is an 80% chance of getting above the long term April to June median rainfall of 80mm at Emerald, a 73% chance of getting or getting above the April to June median rainfall of 91mm at Wandoan and a 67% chance of getting or getting above the April to June median rainfall of 133mm at Rockhampton.

While the seasonal outlook does indicate the potential for continuing relief rain there remains only a relatively low chance of getting the widespread well above average rainfall events needed to break the Queensland drought pattern.

For those interested more information can be found at www.dpi.qld.gov.au/climate or at www.longpaddock.qld.gov.au

As always when dealing with a probability based forecast system it is important to consider the alternate view. For example, currently there is an 80% chance of getting above 80mm at Emerald. This also means there is a 20% chance of not getting above 80mm.

Another way of looking at this is that in 8 years out of 10 (or slightly more than three quarters) with the current SOI pattern, Emerald has received more than 80mm for April to June. Therefore in 2 years out of 10 (or around one quarter) with the current SOI pattern, less than 80mm has been recorded at Emerald.

As rainfall probabilities and median rainfall levels vary throughout the year and from location to location, we strongly recommend referring to Australian Rainman for more specific rainfall data.

For those who like to follow historical patterns more closely, other years that have had a "Consistently Negative" SOI phase at the end of March include 1998, 93, 92, 87, 83, 78, 41, 26, 19, 15, 12, 06 and 1905. It can be very useful to find out what rainfall patterns and seasonal conditions where like during April to June in your area for those years.

Whopper Cropper simulations can be used to prepare a number of cropping scenarios for the coming winter season. These scenarios can take into account the changing seasonal outlook, soil moisture levels and different crop types.

What is already known is that a very real advantage for growers is there if they know the amount of available soil moisture. For example on the Darling Downs, wheat and barley median yields can vary from 1.5 tonnes per hectare with a soil moisture profile of one-third to three tonnes per hectare with a soil moisture profile of two-thirds.

Therefore knowing the current stored moisture level will allow producers to optimise input levels and potential returns. For more detail on Whopper Cropper contact Howard Cox on 46881381.

The El Nino pattern has measurably weakened during February. Not only will this El Nino event be remembered for it's impact on rainfall patterns but also on expected crop yields and animal production Australia wide.

There is increasing optimism (based on ongoing changes in both the atmosphere and Pacific) that this pattern is breaking down. While this is positive news, all indications suggest that it will linger through to mid/late autumn. Current sea temperature maps can be found at www.longpaddock.qld.gov.au

Occasionally, average to above winter rain and potential high winter crop yields occur during the winters following an El Nino event. Some years that were examples of this include 1978, 1983, 1988, and 1998 (although 1998 was actually too wet in many areas with resultant crop diseases).

While the risk is low, there remains a chance that the El Nino will regenerate in some form during autumn/winter this year. Autumn 1992 is a good example of a partial breakdown in an El Nino pattern with it then reforming in early winter (not necessarily as a classic El Nino but something close to it). Some relief rain followed by a fairly dry winter usually characterizes this type of pattern. These types of years include 1992, 1993, 1994, 1940, 1941, 1912, 1913, 1914, and 1915.

The Climate Prediction Centre (CPC) in the United States http://www.cpc.ncep.noaa.gov/ and the International Research Institute http://iri.ldeo.columbia.edu/ are a good source of information on El Nino development.

Ocean and coupled ocean/atmosphere forecast models (GCM's) give an indication as to likely ENSO development out to 9 months. Of the 10 models that forecast out to July 2003, 7 indicate the development of neutral sea temperature pattern, 2 indicate ongoing El Nino (or warm) sea temperature pattern and 1 indicates the potential development of a La Nina (or cold) sea temperature pattern.

Of the 7 models that forecast out to October 2003, 6 indicate the development of a neutral sea temperature pattern while 1 indicates the development of a La Nina sea temperature pattern.

GCM outputs should be viewed cautiously at this time of year as we are approaching the so-called "predictability barrier" between March and June. More details can be found at www.bom.gov.au/climate/ahead/ENSO-summary.shtml

For more specific climate information for your location refer to Australian Rainman, the latest "Climate Note" at www.dpi.qld.gov.au/climate or ring the DPI Call Centre on 13 25 23.