It has been notably hotter and drier than usual this month up to April 23 in Perth after the driest October to March period in 142 years of records.
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This month in Perth, the mean maximum temperature to date is 30 degrees and does look certain to break the record hot April of 28.6 degrees set back in 1978.
Looking at the records for April 1978 in North East Victoria, it was cooler than normal at most places in our region, somewhat similar to that of this year after a warm, dry March.
We had a very warm start to May in 1978 in our region, but widespread heavy rain arrived on May 10 and another burst of heavy rain during the third week.
The rest of 1978 tended to be wetter than average, particularly November and December.
By a striking contrast, on the west coast of South Australia this month up to April 23, it has been exceptionally cold.
At Ceduna, the mean maximum temperature to date is 20.6 degrees, nearly 4 degrees below the April normal and the coldest for April since 1946.
The mean minimum temperature at Ceduna to date is 6.8 degrees, 4 degrees below the April normal and the coldest since 6.5 degrees in April 1999.
Ceduna recorded a frost last Sunday morning, April 21, with the temperature falling to 0.9 degrees, the coldest in April since 1999.
More than 10 other towns around Kingscote, Keith, Lameroo, Renmark, Loxton and Adelaide recorded their lowest April temperature, with light frosts, also since 1999.
The effect of this very cold spell in April 1999 over most of South Australia did lead to heavy rain near the end of May 1999 in North East Victoria and again in early June and near the end of August.
The winter of 1999 in North East Victoria was slightly warmer than normal.
The last two months of 1999 was certainly wetter and cooler than usual in North East Victoria. Much the same conditions are anticipated for the rest of this year.
The striking contrast between Perth and Ceduna this month was due the persistent blocking situation for nearly all of April, with a large high pressure system sitting just west of the Great Australian Bight.
Perth itself was located on the western side of this large high pressure with persistent warmer northeasterly winds and thus higher than normal temperatures, whilst Ceduna was affected by cooler and drier south-southwesterly winds and much lower than normal temperatures.
Currently a small low pressure system is advancing eastwards from the Bight and will bring two days of maximum temperatures above normal at Ceduna and across to Victoria, but it will be back to the blocking situation again when the high pressure system intensifies west of the Bight.
Cocos Islands is now certain to record its warmest January to April period in 72 years of records. The previous warmest January to April period at Cocos Islands was back in 1998.
The January to April rainfall up to April 21 was 309.6 millimetres, the driest since 236 millimetres in 1991.
This will affect our region by providing much needed rainfalls in the coming months after a dry autumn to date.
Most districts in our region in 1991 had well above average rainfall from May to July and again the following summer 1991-92.
For 1998, most districts had well above average rain from late April to November 1998.
