Seasonal Climate Outlook Message for May to August 2008

The bottom line

Cooler than usual winter days likely

According to the Bureau of Meteorology we can look forward to cooler days and average nights. There is only a 35 to 45 % chance of exceeding median maximum daytime temperatures.

Overnight minimum temperatures are expected to be about normal, rather than distinctly colder or warmer than usual for this time of year (May to July). For more information go to the climate page (http://www.bom.gov.au/climate) and then go to the temperature outlook.

This outlook means you could expect the average number of frosts this year for your area. The Bureau of Meteorology also has a daily frost potential at http://www.bom.gov.au/jsp/watl/weather/frost.jsp http://www.bom.gov.au/jsp/watl/weather/frost.jsp> or simply go to the Bureau site and search for "frost".

April has continued dry although the SOI has remained positive with a thirty day average of plus 0.7. The outlook based on this SOI and historical rainfall records continues indicates a 40 to 60 % (or more or less even) chance of receiving median rainfall. So this year (2008) may fall in the 4 to 6 years out of ten that receive below median rainfall for a consistently positive SOI. Remember the forecast covers May to July so regions could still exceed their median rainfall for the three month period.

Any probability forecast is just that - a probability. A 60 % chance of getting above median rainfall also means that there is still a 40 % chance of not receiving median rainfall. That is, say your locality has a 60 % chance of exceeding the median rainfall. For instance if your median for February is 100mm, then in other years with an SOI similar to this, 6 times out of 10 there was more than the median. In 4 out of the 10 years less than 100mm fell.

In terms of median rainfall although the dry season has started most areas could still expect some rainfall. For example, at Dalby the median May to July rainfall is 97 mm and there is a 57% chance of exceeding that amount. At Emerald the median May to July rainfall is 74 mm, and again here is a 57% chance of exceeding that amount. At Longreach the median May to July rainfall is 49 mm, and there is a 56% chance of exceeding that amount. For more specific rainfall probabilities for your location refer to Rainman Streamflow.

For more information on probabilities, or to explore median rainfall figures try Rainman Streamflow available from the DPI&F on 13 23 25.