Weather

Perth 28-day rainfall forecast

Sun Mon Tue Wed Thu Fri Sat
      24
 
 
25
 
 
26
 
 
27
Low
 
28
 
 
29
 
 
30
 
 
31
Low
 
1
Low
Feb
2
 
 
3
 
 
4
 
 
5
 
 
6
 
 
7
 
 
8
 
 
9
 
 
10
 
 
11
 
 
12
Low
 
13
 
 
14
 
 
15
 
 
16
 
 
17
 
 
18
 
 
19
 
 
20
 
 
       

Chance of rainfall somewhere within district

Nil
<25%
Low
25-50%
Medium
50-75%
High
≥75%

Issue Notes

Issued 23 Jan 2018

The hemispheric long wave pattern has been relatively fast moving in recent weeks. There are six main troughs. Currently the most significant troughs are near the longitudes of South Africa, the southwest Indian Ocean, eastern Australia, the south Pacific, and South America. Summary: Over southern and eastern Australia the cold front events with potential to bring widespread rain are now expected about 2 February to 6 February, 13 February to 17 February, and 19 February to 23 February. Rain events originating in the tropics and moving south are possible about 28 January to 1 February, 4 February to 8 February, and 15 February to 19 February. Over Western Australia the strongest cold fronts should occur about 7 February to 11 February, and 13 February to 17 February.

Forecast Explanation

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.