7 day weather forecast

Effective as of 4:00 PM Friday September 28

Explanatory notes:

A west trough coast deepens down the west coast as an upper/middle level trough/disturbance arrives bringing showers and possible thunderstorms and the formation of a low during the weekend.

A middle level cloud band affects the region tomorrow ahead of an upper/middle level trough/disturbance.Some uncertainty on the precise behaviour of the clouds and rain tomorrow with variation between models and model ensembles.ECMWF has mainly morning precipitation,unlike the GFS and ACCESS.etc.Uncertainty in temperatures as well as that depends on cloud cover and precipitation.

Low to the northwest strengthens,with showers and thunderstorms possible again on Sunday.

Another west coast trough possibly deepens near the west coast from mid next working week with another upper/middle level trough/disturbance arriving possibly bringing showers and thunderstorms.

The rest of Friday September 28:

High clouds(partly cloudy)

Chance of any rain:0%

Perth metropolitan area:

High clouds(partly cloudy).Winds east to east-southeasterly at 15-30 km/h strengthening to 25-40 km/h later at night.Wind gusts in excess of 65 km/h possible over the hills and foothills later at night.

Saturday September 29:

12-23 Degrees Celsius

Showers,possible thunderstorm.

Chance of any rain:95%

Amount:2 to 8 mm.

Perth metropolitan area:

Partly to mostly cloudy.A very high(95%) chance of showers.The chance of a thunderstorm.Winds easterly at 20-35 km/h shifting southeasterly from afternoon.

Sunday September 30:

12-22 Degrees Celsius

Possible showers and thunderstorms clearing.

Chance of any rain:50%

Amount:0 to 3 mm.

Perth metropolitan area:

A medium(50%) chance of showers clearing to mostly sunny conditions by late afternoon.The chance of thunderstorms clearing by late afternoon.Light winds shifting southwesterly at 20-35 km/h from late morning becoming south-southeasterly at night.

Monday October 1:

11-22 Degrees Celsius

Mostly cloudy.

Chance of any rain:10%

Amount:0 mm.

Perth metropolitan area:

Mostly cloudy.Winds southeasterly at 10-20 km/h tending southwesterly near the coast during the afternoon.

Tuesday October 2:

11-23 Degrees Celsius

Partly cloudy.

Chance of any rain:20%

Amount:0 mm.

Perth metropolitan area:

Partly cloudy.A slight(30%) chance of a shower over the hills in the afternoon,a slight(20%) chance elsewhere.Light winds.

Wednesday October 3:

10-23 Degrees Celsius

Possible shower or two.

Chance of any rain:40%

Amount:0 to 1 mm.

Perth metropolitan area:

Partly to mostly cloudy.A medium(40%) chance of showers.The chance of a thunderstorm.Winds southeasterly at 15-25 km/h.

Thursday October 4:

11-21 Degrees Celsius

Possible shower or two.

Chance of any rain:40%

Amount:0 to 2 mm.

Perth metropolitan area:

Partly to mostly cloudy.A medium(40%) chance of showers.The chance of a thunderstorm.Winds southeasterly at 10-20 km/h.

Friday October 5:

11-22 Degrees Celsius

Possible shower.

Chance of any rain:30%

Amount:0 to 1 mm.

Perth metropolitan area:

Partly to mostly cloudy.A slight(30%) chance of showers.Light winds.

Charts:

Figure 1.Surface synoptic chart at 12 UTC(8 PM local time yesterday).Image courtesy of the Australian Bureau of Meteorology(BOM)

Figure 3.Key features identified on True Colour RGB satellite image at around 06:00 UTC(2 PM local time yesterday).Satellite image courtesy of the Japanese Meteorological Agency(JMA).

Figure 3.Mean Sea Level Pressure(MSLP) analysis with infrared greyscale satellite image at 12 UTC(8 PM 
local time yesterday).Image courtesy of the Australian Bureau of Meteorology(BOM).

Figure 4:Surface synoptic prognosis.Image courtesy of the Australian Bureau of Meteorology(BOM).

Forecast for today produced at 12:00 AM,forecast for the rest of the days produced at 4:20 PM Wednesday July 11.Weather icons courtesy of the US National Weather Service.