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Lower Derwent 28-day Rainfall Forecast

Sun
Mon
Tue
Wed
Thu
Fri
Sat
26
med
27
high
28
high
29
high
30
high
Oct 1
high
2
high
3
high
4
high
5
low
6
med
7
high
8
high
9
med
10
med
11
med
12
med
13
low
14
med
15
low
16
high
17
med
18
med
19
high
20
high
21
low
22
high
23
high
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 fast moving in recent weeks. There are five main troughs. Currently the most significant troughs are near the longitudes of South Africa, the Indian Ocean, Western Australia, the south 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 1 October to 5 October, 5 October to 9 October, and 14 October to 18 October. Rain events originating in the tropics and moving south are possible about 1 October to 5 October, 11 October to 15 October, and 23 October to 27 October.
Over Western Australia the strongest cold fronts should occur about 2 October to 6 October, 14 October to 18 October, and 26 October to 30 October.

Issued Sep 25

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.

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NSW Weather: Forbes farmers brace for extensive crop losses from flooding

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