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Brecon Beacons mountain area forecast

Forecast issued: 0237 on Friday, 29 August 2014

Overview for Friday

A cloudy day with showers merging into longer spells of rain by late morning and continuing through the afternoon. Windy, with upland gales.

Hazards

High risk of Gales: Southwesterly winds 30-35mph with gusts up to 50-55mph across summits and ridges.

High risk of Persistent extensive hill fog: Hill fog widespread and lingering throughout the day, lowest bases in the west.

Low risk of Severe chill effect: Wind chill making it feel closer to 3C or 4C across the summits.

Low risk of Heavy persistent rain: Showery outbreaks of rain, becoming heavy and persistent across western hills by midday.

No risk of Blizzards; Heavy snow; Storm force winds; Thunderstorms; Strong sunlight;

Weather summary and probability of precipitation for Friday

Dawn to 0900 Light rain Light rain 70-90% chance of precipitation
0900 to 1200 Light rain Light rain 70% chance of precipitation
1200 to 1500 Heavy Rain Heavy Rain 90% chance of precipitation
1500 to dusk Light rain Light rain 90% chance of precipitation

Detailed mountain weather forecast

Friday

Weather

Large areas of low cloud this morning with some showery outbreaks of rain and drizzle developing. These showery outbreaks will merge into longer spells of rain into the afternoon with some heavy rain likely, especially across western hills. This rain will linger through much of the afternoon, before easing away through the evening. It will be a windy day with southwesterly gales leading to significant buffeting, especially across exposed ridges and summits where there will be a marked wind chill.

Visibility

Generally good below the cloud bases, but moderate to poor in the showers/rain and very poor where shrouded in the cloud.

Hill fog

Extensive bases around 500-700m at dawn, with patches down to 200m. Cloud is likely to shroud the hills for much of the day with the best chance of some clearances across eastern hills in the morning and evening.

Maximum winds above 400m

Southwesterly 30-35mph with gusts up to 50-55mph across summits and ridges.

Temperature

Valleys: Plus 11 becoming 18 Celsius
800 m: Plus 10 Celsius
Freezing level: Above the summits.

Saturday

Weather

It will be a rather cloudy morning with some showery outbreaks. However, by midday, the showers will become well scattered and sunny spells developing. The showers and fresh to strong westerly winds will ease into the evening.

Visibility

Generally very good, but moderate to poor in the showers and less than 100m where shrouded in the cloud.

Hill fog

Areas of low cloud, extensive across western hills, above 500m overnight. This will lift and break up through the morning with all summits becoming clear of cloud during the afternoon.

Maximum winds above 400m

Westerly 25-30mph with gusts 40mph across summits and ridges.

Temperature

Valleys: Plus 10 becoming 18 Celsius
800 m: Plus 10 Celsius
Freezing level: Above the summits.

Outlook

Sunday

After a rather cloudy start with some patchy light rain possible, it will brighten up with some sunny spells developing for a time. However, thickening cloud will bring some outbreaks of rain across the park later in the evening. Moderate becoming fresh southwesterly winds.

Monday

Becoming increasingly cloudy with extensive hill fog and patchy light rain and drizzle developing. Moderate southwesterly winds.

Tuesday

Any early hill fog and patchy drizzle will clear away to leave a dry day with variable amounts of cloud and sunny spells. Feeling warm in the sunny spells with light winds.


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