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Snowdonia

Confidence

High for Sunday and Monday. Medium in details for Tuesday, Wednesday and Thursday.

  • This evening
  • Sunday
  • Monday
  • Further outlook

Saturday 18 November 2017

Sunrise: 07:45   Sunset: 16:17
Moon phase: New

Dry with patchy cloud cover over the tops.

Sunday 19 November 2017

Weather hazards

Gales Medium likelihood Hide detail

Progress will be impeded by very strong winds. Walking will be difficult and strenuous at times with a potential for one to be blown over in gusts. There can be a marked increase in winds through cols or on exposed ridges and summits. Distances often take longer to cover with compass bearings becoming more difficult to follow accurately.

Severe chill effect Medium likelihood Show detail

Wind significantly lowers the ‘feels-like’ temperature relative to the actual temperature, with even moderate winds significantly adding to the chilling effect. Strong winds can result in a severe and debilitating wind chill many degrees below the actual temperature. This effect will be enhanced in rain or wet snow. Without protection, prolonged exposure could result in frost nip or frostbite on exposed parts of the body and/or hypothermia.

Poor visibility Low likelihood Show detail

Poor visibility presents challenging route finding conditions. Visibility could be significantly less than 50 metres in all directions with few or no visual references, especially on featureless moors or plateaux. Distances become hard to judge and cliff or cornice edges can be difficult to recognise. These conditions require good navigational skills. There is a risk of white-out conditions when mist or fog is combined with extensive snow cover.

Forecast

A bright start. Becoming cloudy with rain and strengthening winds later.

Weather at 800m

00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
Partly cloudy night Partly cloudy night Partly cloudy night Sunny intervals Cloudy Cloudy Drizzle Heavy rain
00% 00% 00% 00% 00% 10% 40% 70%
Chance of precipitation
900 900 800 900 900 2,000 2,100 1,800
Freezing level (m)
The level above which snow is expected to settle or the ground is expected to be frozen

Wind speed and direction (mph) By altitude above mean sea level

00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
900m NW 17 20 NW 17 21 NW 15 18 SW 7 9 SW 12 15 SW 22 26 S 28 33 SW 37 45
600m NW 9 12 NW 8 11 NW 7 10 SW 5 7 SW 10 13 S 17 21 S 20 25 S 23 30
300m W 3 9 W 2 8 W 2 7 S 3 5 S 6 10 S 9 17 S 11 22 S 12 25
Valley W 7 12 NW 4 9 W 6 11 W 5 8 SW 10 15 SW 12 21 SW 16 28 SW 16 30

Temperature (°C) By altitude above mean sea level

00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
900m 1 1 1 1 1 2 3 4
600m 3 3 3 3 4 4 4 5
300m 5 5 5 5 6 6 6 7
Valley 5 5 5 5 7 7 7 8

Feels like temperature (°C) By altitude above mean sea level

00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
900m -5 -6 -5 -3 -4 -4 -4 -3
600m -1 0 0 1 0 -1 -1 0
300m 3 4 4 4 4 4 3 4
Valley 4 4 4 4 5 5 5 5
Sunrise: 07:47   Sunset: 16:16
Moon phase: New

Weather

Dry with patchy cloud cover over the tops overnight. A bright start with a few sunny breaks. The cloud will thicken from the west, patchy light rain possible from dusk. The rain will turn heavy and persistent later in the evening, the cloud also lowering and winds strengthening.

Chance of cloud-free mountain/hill tops at 800m

60 to 80% overnight and during the morning. Patchy cloud near or above the summits. Becoming 30% by dusk and Nil in the evening as the cloud thickens and lowers.

Visibility

Mainly very good overnight and during daylight hours. Becoming moderate or poor later in the evening, very poor at height.

Meteorologist's view

Nothing further to add.

Ground conditions

No adverse ground conditions reported on 18 of Nov

Monday 20 November 2017

Sunrise: 07:49   Sunset: 16:15
Moon phase: New

Weather

Cloudy with outbreaks of rain and drizzle. The rain heavy at times in the morning. Some drier spells possible in the afternoon. \very windy over the tops with significant wind chill, gales at times.

Temperature

  • At 800m Plus 6 Celsius
  • Valley Plus 10 to 12 Celsius
  • Freezing level 2000m

Visibility

Often poor or very poor at height, but moderate or good lower down.

Chance of cloud-free mountain/hill tops at 800m

Nil to 30%, cloud extensive with bases 300 to 600m, perhaps lifting a little in the afternoon.

Maximum wind speed expected

West or southwest 30 to 40mph, gust 60mph.

Tuesday 21 November 2017

Sunrise: 07:50   Sunset: 16:13
Moon phase: New

Cloudy with outbreaks of rain and drizzle, possibly heavy and persistent at times. Hill fog. Strong to gale force southwest winds.

Wednesday 22 November 2017

Sunrise: 07:52   Sunset: 16:12
Moon phase: Waxing crescent

Cloudy with outbreaks of rain and drizzle. Hill fog. Gale or severe gale force southwest winds.

Thursday 23 November 2017

Sunrise: 07:54   Sunset: 16:11
Moon phase: Waxing crescent

Mostly cloudy with outbreaks of rain and drizzle. Hill fog. Gale force southwest winds.

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