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

Sections

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

This week’s weatherCardiff, United Kingdom

Rain is likely in Cardiff on Tuesday

Nearly all of NOAA’s 31 GEFS forecasts bring measurable rain to Cardiff Tue 7 p.m.–1 a.m. BST; 3 in 10 bring 2.5 mm or more.

NOAA GEFS, 31 forecasts · Mon 28 Sep 18Z run · updated Tues., Sept. 29, 12:03 a.m. BST · times are Cardiff’s (BST)

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

Quick answers

Will it rain in Cardiff this week?
The best chances of measurable rain: Tuesday (nearly all forecasts, 7 p.m.–1 a.m.); Wednesday (nearly all forecasts, 1–7 a.m.). Drier: Thu, Sat, Sun (fewer than 2 in 10 forecasts in any six hours). Times are BST.
How much rain will Cardiff get this week?
By Mon., Oct. 5, 7 p.m. BST (the end of the forecast), the middle forecast has 12 mm of rain and melted snow, counting from Tue 1 a.m. 4 in 10 forecasts bring 13 mm or more in total.
How windy will it get in Cardiff?
Gusts over 48 km/h: 9 in 10 forecasts at Tue 7 p.m. BST. The middle forecast’s strongest gust is 55 km/h, Wed 1 a.m. Checked every six hours, so a brief peak can fall between.
How warm or cold will it be in Cardiff?
At the six-hourly times, the middle forecast runs from 12°C (Sun 7 a.m.) to 20°C (Tue 1 p.m.) BST. The day’s real high and low can fall between those times.
Are any storms heading for Cardiff?
No storm Stormlines tracks has 1 in 10 forecasts passing its centre within 160 kilometres of Cardiff this week.

Chance of rain, six hours at a time

Tue 1–7 a.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneTue 7 a.m.–1 p.m.: 2 in 10 forecasts with measurable rain; middle forecast almost noneTue 1–7 p.m.: 7 in 10 forecasts with measurable rain; middle forecast 0.8 mmTue 7 p.m.–1 a.m.: nearly all forecasts with measurable rain; middle forecast 1.7 mmWed 1–7 a.m.: nearly all forecasts with measurable rain; middle forecast 5.5 mmWed 7 a.m.–1 p.m.: 4 in 10 forecasts with measurable rain; middle forecast almost noneWed 1–7 p.m.: 8 in 10 forecasts with measurable rain; middle forecast 0.6 mmWed 7 p.m.–1 a.m.: 4 in 10 forecasts with measurable rain; middle forecast almost noneThu 1–7 a.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneThu 7 a.m.–1 p.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneThu 1–7 p.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneThu 7 p.m.–1 a.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneFri 1–7 a.m.: 1 in 10 forecasts with measurable rain; middle forecast almost noneFri 7 a.m.–1 p.m.: 2 in 10 forecasts with measurable rain; middle forecast almost noneFri 1–7 p.m.: 2 in 10 forecasts with measurable rain; middle forecast almost noneFri 7 p.m.–1 a.m.: 2 in 10 forecasts with measurable rain; middle forecast almost noneSat 1–7 a.m.: 1 in 10 forecasts with measurable rain; middle forecast almost noneSat 7 a.m.–1 p.m.: 1 in 10 forecasts with measurable rain; middle forecast almost noneSat 1–7 p.m.: 1 in 10 forecasts with measurable rain; middle forecast almost noneSat 7 p.m.–1 a.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneSun 1–7 a.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneSun 7 a.m.–1 p.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneSun 1–7 p.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneSun 7 p.m.–1 a.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneMon 1–7 a.m.: fewer than 1 in 10 forecasts with measurable rain; middle forecast almost noneMon 7 a.m.–1 p.m.: 1 in 10 forecasts with measurable rain; middle forecast almost noneMon 1–7 p.m.: fewer than 1 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, BST.

The week, day by day

DayChance of rain2.5 mm or moreTotal by day’s endStrongest gustTemperature
Tue 29nearly all3 in 102.6 mm · <1 in 1053 km/h12°C–20°C
Wed 30nearly all9 in 1010 mm · 3 in 1055 km/h16°C–19°C
Thu 1<1 in 10<1 in 1010 mm · 3 in 1030 km/h13°C–16°C
Fri 22 in 101 in 1011 mm · 4 in 1023 km/h13°C–17°C
Sat 31 in 10<1 in 1012 mm · 4 in 1010 km/h13°C–16°C
Sun 4<1 in 10<1 in 1012 mm · 4 in 1012 km/h12°C–16°C
Mon 5 (part)1 in 10<1 in 1012 mm · 4 in 1021 km/h12°C–17°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 1 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 Cardiff

No storm Stormlines tracks has 1 in 10 forecasts passing its centre near Cardiff 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 Cardiff’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.

Other cities →