Seasonal Climate Outlook Message for July to October 2003
The bottom line
(dated 01/07/03)
Given some recent media coverage it is essential that I highlight that the break down of the 2002/03 El Nino sea temperature pattern does not automatically mean an immediate end to ongoing widespread drought conditions.
Rainfall probabilities for Queensland are an improvement over the situation this time last year. However they are currently not high enough to guarantee state wide drought breaking rains in the medium term.
In order to improve the overall seasonal outlook sustained positive monthly SOI values are needed over the next few months. If the SOI does not return to more positive monthly values by the end of July, rainfall probabilities would be expected to substantially fall in value for the following months.
The current pattern does suggest the potential for some relief rain across the state for winter. Based on the recent SOI pattern, there remains a 50-70% chance of getting above the long term July to September average for southern Queensland. Rainfall probabilities across the rest of the state though are lower around 30-50%.
It's also worth pointing out that at this time of year the long term median rainfall totals for Queensland are relatively low as August and September are the 2 driest months of the year in many areas. For example Roma has a long term July to September median rainfall of 75mm, Quilpie has 34mm, Mareeba has 16mm, Cloncurry has 9mm, Laura has 3mm and Normanton has 1mm.
The full story
El Nino Breaks Down But Dry Conditions Continue In Many Parts (Dated 01/07/03)
Given some recent media coverage it is essential that I highlight that the break down of the 2002/03 El Nino sea temperature pattern does not automatically mean an immediate end to ongoing widespread drought conditions.
Rainfall probabilities for Queensland are an improvement over the situation this time last year. However they are currently not high enough to guarantee state wide drought breaking rains in the medium term.
In order to improve the overall seasonal outlook sustained positive monthly SOI values are needed over the next few months. For example, if the SOI does not return to more positive monthly values by the end of July, rainfall probabilities would be expected to substantially fall in value for the following months.
Based of the monthly value of the SOI from the end of May (minus 5) to the end of June (minus 13.2) the SOI is in a 'Rapidly Falling' phase.
For those interested in following historical rainfall patterns more closely, some of the years that have had a 'Rapidly Falling' phase at the end of June include 2000, 1993, 1990, 1988, 1985, 1984, 1983, 1982, 1965, 1963, 1959, 1949, 1948, 1943, and 1941.
It can be useful to find out what rainfall and farming conditions where like in your area for July to September in those years. Information on what rainfall patterns where like in those years is available at www.longpaddock.qld.gov.au
In the mean time there remains the potential for some relief rain in Queensland during winter. Currently there is a 50-70% chance of getting above the long term July to September average for southern Queensland. Rainfall probabilities across the rest of the state though are lower around 20-50% depending on location (refer to map).
It's also worth pointing out that at this time of year the long term median rainfall totals for much of Queensland are quite low as August and September are the 2 driest months of the year in many areas. For example Roma has a long term July to September median rainfall of 75mm, Quilpie has 34mm, Mareeba has 16mm, Cloncurry has 9mm, Laura has 3mm and Normanton has 1mm.
As always, when using any probability based forecast system, it is important to consider the alternate view. For example, currently Kingaroy has a 70% chance of getting above 70mm for July to September. This also means that there is a 30% chance of not getting above 70mm.
Another way of looking at this is that in 7 years out of 10 (or around three quarters of years) with the current SOI pattern, Kingaroy has received more than 70mm for July to September. Therefore in 3 years out of 10 (or around one quarter of years) with this SOI pattern, Kingaroy has received less than the long term July to September median rainfall of 70mm.
Information received from international agencies showed that the chance of a new El Nino developing in the short term is low (but not impossible). While the current sea surface temperature pattern is an improvement over the last 12 months it has not changed significantly to guarantee a large improvement in current conditions.
Due to the size of the area covered, the information provided in this column is of a fairly broad nature. For those readers who require more specific climate information, we recommend referring to Australian Rainman, the latest "Climate Note" at www.dpi.qld.gov.au/climate or contact us through the DPI Call Centre on 13 25 23.
