Weather forecast for Perth effective as of 12:00 AM Tuesday March 20

Weather forecast for Perth effective as of 12:00 AM Tuesday March 20:

Explanatory notes:
Scroll down below this section for forecast. 

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

Figure 2.Key features identified on True Colour RGB satellite image at around 07:00 UTC(3 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).

Boundary layer decoupling lead to colder than expected conditions on Monday morning.The boundary layer also decoupled temporarily on Monday night before boundary recoupling as winds strengthened.

Some high clouds affecting the region  streaming in a subtropical  jet stream.

On Tuesday especially plenty of high clouds with moist air streaming in a subtropical jet stream and later some middle level clouds as well ahead of a middle level disturbance,virga possible but unlikely to reach the ground with a thick layer of dry air below the clouds.

Plenty of middle and high level clouds on Wednesday as well,with plenty of virga expected,slight chance of reaching the ground.


A west coast trough lied slightly offshore leading to warm air advection.Some uncertainty on how hot it will be on Wednesday as it depends on cloud cover with plenty of middle level clouds possible.

The west coast trough likely moves inland on Thursday with the marine layer advecting inland.

Plenty of uncertainty on the precise synoptic conditions late during the week as it depends on the movement of Tropical Cyclone Marcus but an easterly pressure gradient is likely.

Tuesday March 20:

City:

20-34 Degrees Celsius

Clouds increasing.

Chance of any rain:5%

Amount:0 mm.

Perth metropolitan area:

Partly cloudy becoming  cloudy by night,high clouds.Winds easterly at 20-35 km/h easing to east-southeasterly at 10-20 km/h during the afternoon increasing to easterly at 15-30 km/h at night.

Wednesday March 21:

City:

24-35 Degrees Celsius

Mostly cloudy.

Chance of any rain:20%

Amount:0 mm.

Perth metropolitan area:

Mostly cloudy.A slight(20%) chance of a shower.Winds east-northeasterly at 15-30 km/h increasing to 20-30 km/h at night.

Thursday March 22:

City:

21-29 Degrees Celsius

Mostly sunny.

Chance of any rain:0%

Amount:0 mm.

Perth metropolitan area:

Mostly sunny.Winds northeasterly at 10-20 km/h becoming southwesterly at 15-25 km/h during the day becoming south-southwesterly at 10-20 km/h at night.

Friday March 23:

City:

17-29 Degrees Celsius

Partly cloudy.

Chance of any rain:5%

Amount:0 mm.

Perth metropolitan area:

Partly cloudy.Winds south-southwesterly at 15-25 km/h.

Saturday March 24:

City:

17-28 Degrees Celsius

Partly to mostly cloudy.

Chance of any rain:10%

Amount:0 mm.

Perth metropolitan area:

Partly to mostly cloudy,high clouds.Winds southeasterly at 15-25 km/h.

Sunday March 25:

City:

16-29 Degrees Celsius

Mostly cloudy.

Chance of any rain:5%

Amount:0 mm.

Perth metropolitan area:

Mostly cloudy.Winds easterly at 15-30 km/h.

Monday March 26:

City:

18-27 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.Winds northeasterly at 15-30 km/h shifting southwesterly during the day.

Forecast for today produced at 11:30 PM Monday March 19,forecast for the rest of the days produced at 4:20 PM Monday March 19.Weather icons courtesy of the US National Weather Service.