What changes for beach days and trips?
Anyone heading to the coast on La Palma on Saturday 7 November should expect a yellow AEMET warning for coastal hazards from 18:00. Forecasters expect south or south-westerly wind of 50 to 61 kilometres per hour, force 7, mainly in the north-west.
Protección Civil, the civil protection service, advises avoiding beaches and low-lying coastal areas in such conditions. No wave heights for the Canaries had been published by Friday.
Reports up to Friday mention yellow warnings only for La Palma, and no orange or red ones. Visitors to Tenerife, Gran Canaria or Lanzarote should still check the AEMET warnings page before every beach day, because levels can change.
Which warnings apply on La Palma?
A yellow AEMET rain warning has applied on La Palma since 00:00 on Friday 6 November, covering three zones: the summits, the east and the west. The threshold is around 15 litres per square metre in one hour.
Rain will be heaviest on slopes facing south and west, according to the Canaries emergency service (Dirección General de Emergencias). Sources describe the 15-litre threshold inconsistently, sometimes as a maximum and sometimes as a minimum.
A yellow wind warning follows on Saturday from 12:00, with gusts of up to 70 kilometres per hour. It mainly affects the summits, the north-west and the east coast, and reports do not say when the warnings end.
From 00:00 on Friday, the Canary Islands government has declared the pre-alert level (prealerta) for rain on La Palma. It bases this on the PEFMA, the regional emergency plan for adverse weather.
What about the other islands?
Tenerife, La Gomera and El Hierro get less rain on Friday than La Palma, AEMET forecasts. Santa Cruz de Tenerife should see 20 to 24 degrees, and Valverde on El Hierro 16 to 21 degrees.
Gran Canaria, Lanzarote and Fuerteventura have plenty of high cloud and long dry spells on Friday. AEMET forecasts 20 to 25 degrees for Las Palmas de Gran Canaria and 20 to 24 degrees for Arrecife.
Saturday is the trickiest day for hikes on mountain roads. From midday the forecast expects very strong south-westerly gusts on La Palma and on the central summits of Tenerife, though figures in km/h are missing for Tenerife.
On Sunday 8 November the weather worsens, mainly in the western province, says the forecast. Showers may be heavy to very heavy, with thunderstorms and persistent rain, especially on La Palma.
Rain reaches the other islands on Sunday too, but stays moderate and less likely on Lanzarote and Fuerteventura. The forecast expects very strong gusts in the mid-altitude areas (medianías) and on the summits.
Who issues the warnings, and what do the levels mean?
Two bodies issue warnings separately. AEMET uses yellow, orange and red, while the Canaries emergency service uses the PEFMA levels prealerta, alerta and alerta máxima.
According to Canary Islands government statements, the pre-alert level means no risk for the general public, but a risk for certain activities or particularly exposed places. The alerta level, by contrast, signals danger to people, property and the environment.
The emergency service asks people to follow the warnings and take care on roads and near ravines (barrancos). Protección Civil also advises driving slower, sticking to main roads and avoiding flooded stretches.
What happens after the weekend?
Bruna's fronts hit the Canaries over the weekend. The low itself deepens west of the Azores, reports say, and nears north-west Spain early next week.
Bruna should weaken from Wednesday 11 November, says the forecast. AEMET still does not rule out heavy showers on the Canaries that day.
Nothing had been published by Friday on wave heights, rainfall in millimetres or possible disruption to ferries, flights or schools. AEMET admits that the exact position of the low makes it harder to forecast where the rain will be heaviest.