Sun
Mon
Tue
Wed
Thu
Fri
Sat
18
19
20
21
22
med
23
24
25
26
low
27
low
28
low
29
med
30
med
31
low
Jan 1
low
2
low
3
low
4
5
6
7
low
8
low
9
10
11
12
low
13
low
14
Chance of rainfall within district |
nil < 25% |
low 25% to 50% |
med 50% to 75% |
high ≥ 75% |
Issue Notes
The hemispheric long wave pattern has been relatively slow moving in recent weeks. There are five main troughs. Currently the most significant troughs are near the longitudes of South Africa, the Indian Ocean, New Zealand, the southeast Pacific, and the Atlantic Ocean.
Summary:
Over southern and eastern Australia the cold front events with potential to bring widespread rain are now expected about 21 December to 25 December, 9 January to 13 January, and 15 January to 19 January. Rain events originating in the tropics and moving south are possible about 24 December to 28 December, and 30 December to 3 January.
Over Western Australia the strongest cold fronts should occur about 21 December to 25 December, and 16 January to 20 January.
Issued Dec 16
This forecast is produced by a multi-model ensemble consisting of dynamical atmospheric models,
which are forced by the latest observed atmosphere, ocean, land and ice conditions. The models
are designed to simulate features of the real atmosphere, including the daily movement of long
and short wave patterns in the Southern Hemisphere.
The future probability of rain in each district is estimated using output from the multi-model
ensemble, combined with historical information about the difference between the model forecasts
and observed rainfall.
In this deterministic framework the skill of the forecast tends to decrease with time, however
the forecasts are updated daily to provide the latest estimates of rainfall probability out to
28 days.