Tuesday, May 1, 2012

Seasonal Rainfall Predictions


A dry winter is predicted, why?


The southeast Australian outlook for May to July 2012 shows a drier season is more likely for southeastern SA. 

This outlook is strongly influenced by warmer than normal water temperatures in the Indian Ocean.

If this winter season is drier than median this has a significant effect on the horticultural crops. These crops have finished their season (Grapes, Olives, Strawberries, Almonds and Stonefruit) and winter is an important period in their cycle. Winter rainfall is needed to assist in flushing the soil of salts that build up over the growing season.

Above - Over Tasmania, western and central Victoria, and southeastern SA the chances of receiving above normal rainfall are between 30 and 40%. In other words, the chance of below normal rainfall is between 60 and 70%.

BOM Climate Report 26/4/2012 -

The southeast Australian outlook for May to July 2012 shows a drier season is more likely for Tasmania, Victoria, and southeast SA. This outlook is strongly influenced by warmer than normal waters in the Indian Ocean. 
Climate indicators across the tropical Pacific Ocean remain neutral (neither El Niño or La Niña). Climate models surveyed by the Bureau of Meteorology suggest that the tropical Pacific Ocean will remain at neutral levels at least into early winter. 

All major indicators of ENSO, including cloudiness, trade winds, the Southern Oscillation Index (SOI) and sea surface temperatures in the tropical Pacific, lie well within the ENSO-neutral range. Over the past week, the SOI has returned to values not seen since April 2010. 

Some, but not all, climate models note an increased risk of El Niño conditions evolving during winter or spring. Historically, about 70% of two-year La Niña events are followed by neutral or El Niño phases. 

The Indian Ocean Dipole (IOD) has limited influence on Australian rainfall from December through to April. Model outlooks currently suggest neutral conditions are the most likely scenario heading into the southern winter. 
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For more information visit -  http://www.bom.gov.au/climate/ahead/rain.seaus.shtml

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