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Snowdonia

Weather hazards over 300m on Thu 21 Aug 2014

High risk

No high risks
none

Medium risk

Strong sunlight
Sunny spells between showers will lead to a risk of sunburn

Low risk

Severe chill effect
Unseasonable temperatures and moderate breeze will lead to summits feeling close to freezing.
Persistent extensive hill fog
Ragged patches of hill fog around 600m, mainly near heavy showers.

No risk

Blizzards
none
Heavy snow
none
Storm force winds
none
Gales
none
Thunderstorms
none
Heavy persistent rain
none

Thu 21 Aug 2014

It will be a dry and chilly start to Thursday with clearer spells during the early hours. However cloud will gradually increase from the north and west during the morning bringing an increasing risk of scattered showers. These could bring hill fog at times, especially across western slopes. It will also feel unseasonably cold across the summits, especially in the westerly breeze

Time
0000 to 0300 0300 to 0600 0600 to 0900 0900 to 1200 1200 to 1500 1500 to 1800 1800 to 2100 2100 to 2400
Weather
Partly cloudy night Partly cloudy night Sunny intervals Cloudy Light shower day Light shower day Light shower day Light shower night
Precipitation probability
10% 10% 10% 20% 30% 30% 40% 30%

Visibility

Generally very good to excellent, but falling to moderate in showers and very poor in hill fog.

Hill Fog

Ragged patches at 600m in the west at first, coming and going with the showers. Becoming increasingly extensive during the afternoon. Best chance of cloud free summits across eastern hills.

Max wind above 500m

Westerly 40mph

Temperature

Valleys:
Plus 4 Celsius becoming Plus 17 Celsius
800m:
Plus 5 Celsius
Freezing level:
Above the summits.

Issued at: 1617 on Wed 20 Aug 2014

Fri 22 Aug 2014

Cloudy with scattered showers overnight, and patches of hill fog. Drier and brighter intervals are likely to develop during the day, with the best of these during the afternoon. However a few evening showers are possible, and if these occur they could include the odd thundery burst. Remaining cool, and feeling cold across the summits and ridges.

Visibility

Generally very good, but falling to moderate in showers and very poor in hill fog.

Hill Fog

Patches at 400m, occasionally to 200m in the west during the morning. However breaking up and lifting during the course of the day, with all summits likely to clear by the early afternoon.

Max wind above 500m

Northwesterly 35mph

Temperature

Valleys:
Plus 8 Celsius becoming Plus 17 Celsius.
800m:
Plus 5 Celsius
Freezing level:
Above the summits.

Issued at: 1617 on Wed 20 Aug 2014

Sat 23 Aug 2014

A cold start to the day with grass frost likely in the valleys. A largely fine day will then follow with some lengthy sunshine, and just the low risk of one or two isolated showers, mainly at first. Winds will also be light,

Issued at: 1617 on Wed 20 Aug 2014

Sun 24 Aug 2014

Another largely dry and often sunny day is likely. It is likely to be less cold, with winds turning southwesterly. However cloud will thicken from the southwest during the afternoon, with rain, hill fog and strengthening winds likely overnight.

Issued at: 1617 on Wed 20 Aug 2014

Mon 25 Aug 2014

A rather wet and cloudy day with outbreaks of rain, and gales possible over the highest peaks. Rain could turn heavy for a time in the morning, and whilst temperatures will be closer to normal it will be feeling much colder due to the inclement conditions.

Issued at: 1617 on Wed 20 Aug 2014