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Nerd mode: every forecast, readouts, filters and range & bearing for weather enthusiasts

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Nerd mode: every forecast, readouts, filters and range & bearing for weather enthusiasts

This week’s weatherSydney, Australia

Rain is likely in Sydney on Friday

Nearly all of NOAA’s 31 GEFS forecasts bring measurable rain to Sydney Fri 4–10 p.m. GMT+10; 7 in 10 bring 2.5 mm or more.

NOAA GEFS, 31 forecasts · Mon 28 Sep 18Z run · updated Tues., Sept. 29, 9:03 a.m. GMT+10 · times are Sydney’s (GMT+10)

See it on the globe For warnings, follow your national weather service.

Quick answers

Will it rain in Sydney this week?
The best chances of measurable rain: Friday (nearly all forecasts, 4–10 p.m.); Saturday (nearly all forecasts, 10 p.m.–4 a.m.); Sunday (8 in 10 forecasts, 10 p.m.–5 a.m.); Monday, Oct. 5 (4 in 10 forecasts, 11 p.m.–5 a.m.). Drier: Wed, Thu (fewer than 2 in 10 forecasts in any six hours). Times are GMT+10.
How much rain will Sydney get this week?
By Tues., Oct. 6, 5 a.m. GMT+11 (the end of the forecast), the middle forecast has 30 mm of rain and melted snow, counting from Tue 10 a.m. 7 in 10 forecasts bring 25 mm or more in total; 2 in 10 forecasts bring 51 mm or more.
How windy will it get in Sydney?
Gusts over 48 km/h: 3 in 10 forecasts at Sat 4 p.m. GMT+10. The middle forecast’s strongest gust is 39 km/h, Sat 4 p.m. Checked every six hours, so a brief peak can fall between.
How warm or cold will it be in Sydney?
At the six-hourly times, the middle forecast runs from 13°C (Wed 4 a.m.) to 25°C (Thu 4 p.m.) GMT+10. The day’s real high and low can fall between those times.
Are any storms heading for Sydney?
No storm Stormlines tracks has 1 in 10 forecasts passing its centre within 160 kilometres of Sydney this week.

Chance of rain, six hours at a time

Tue 10 a.m.–4 p.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneTue 4–10 p.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneTue 10 p.m.–4 a.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneWed 4–10 a.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneWed 10 a.m.–4 p.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneWed 4–10 p.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneWed 10 p.m.–4 a.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneThu 4–10 a.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneThu 10 a.m.–4 p.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneThu 4–10 p.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneThu 10 p.m.–4 a.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneFri 4–10 a.m.: 3 in 10 forecasts with measurable rain; middle forecast almost noneFri 10 a.m.–4 p.m.: 7 in 10 forecasts with measurable rain; middle forecast 2.3 mmFri 4–10 p.m.: nearly all forecasts with measurable rain; middle forecast 5.8 mmFri 10 p.m.–4 a.m.: nearly all forecasts with measurable rain; middle forecast 4.1 mmSat 4–10 a.m.: nearly all forecasts with measurable rain; middle forecast 4.0 mmSat 10 a.m.–4 p.m.: nearly all forecasts with measurable rain; middle forecast 1.9 mmSat 4–10 p.m.: 9 in 10 forecasts with measurable rain; middle forecast 0.9 mmSat 10 p.m.–5 a.m.: 8 in 10 forecasts with measurable rain; middle forecast 0.6 mmSun 5–11 a.m.: 7 in 10 forecasts with measurable rain; middle forecast 0.6 mmSun 11 a.m.–5 p.m.: 6 in 10 forecasts with measurable rain; middle forecast 0.4 mmSun 5–11 p.m.: 5 in 10 forecasts with measurable rain; middle forecast almost noneSun 11 p.m.–5 a.m.: 4 in 10 forecasts with measurable rain; middle forecast almost noneMon 5–11 a.m.: 4 in 10 forecasts with measurable rain; middle forecast almost noneMon 11 a.m.–5 p.m.: 3 in 10 forecasts with measurable rain; middle forecast almost noneMon 5–11 p.m.: 4 in 10 forecasts with measurable rain; middle forecast almost noneMon 11 p.m.–5 a.m.: 4 in 10 forecasts with measurable rain; middle forecast almost none

Each bar is the share of the 31 forecasts with measurable rain or melted snow in that six hours; the darker the bar, the more forecasts agree. Local days, GMT+10.

The week, day by day

DayChance of rain2.5 mm or moreTotal by day’s endStrongest gustTemperature
Tue 29 (rest of day)<1 in 10<1 in 10almost none · <1 in 1028 km/h15°C–19°C
Wed 30<1 in 10<1 in 10almost none · <1 in 1033 km/h13°C–23°C
Thu 1<1 in 10<1 in 10almost none · <1 in 1033 km/h16°C–25°C
Fri 2nearly all7 in 1011 mm · 4 in 1037 km/h16°C–23°C
Sat 3nearly all7 in 1027 mm · 9 in 1039 km/h14°C–15°C
Sun 48 in 102 in 1028 mm · nearly all36 km/h14°C–17°C
Mon 54 in 10<1 in 1030 mm · nearly all20 km/h13°C–19°C
Tue 6 (part)4 in 10<1 in 1030 mm · nearly all10 km/h15°C

Chances are the highest in any six hours of the day. “Total by day’s end” is the middle forecast’s running total since Tue 10 a.m., and the share of forecasts with 13 mm or more by then; totals aren’t added up day by day, because the middle forecast of each day isn’t the same forecast. Gusts and temperatures are read every six hours.

Storms near Sydney

No storm Stormlines tracks has 1 in 10 forecasts passing its centre near Sydney this week. Every storm we’re tracking →

About these numbers

They come from one source, NOAA’s Global Ensemble Forecast System (GEFS): 31 runs of the same model, each started slightly differently, read at Sydney’s coordinates on a grid about 55 km (35 miles) apart. “8 in 10 forecasts” means 8 in 10 of those runs. Nothing is adjusted for local effects such as coasts, lakes, hills or city heat, so the numbers can differ from your local official forecast, especially for snow and showers.

“Measurable rain” counts rain or melted snow in a six-hour period. Not an official forecast: follow your national weather service for warnings and decisions. How the forecasts are read: how to read the maps and the glossary.

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