Snowdonia National Park
Includes all summits in the the northern half of Wales from Plynlimon northwards.
Viewing Forecast For
Snowdonia National Park
Friday 4th December 2020
Last updated
Thursday 3rd December 2020 at
4:25 PM
Summary for all mountain areas
Areas of snowfall will pivot in from the east to affect many areas of Scotland and Northern England through the day. Accompanied by upland gales giving severe wind chill for periods, but a substantial lull is likely S Pennines. Across Wales, snow showers later give way to persistent snow.
Headline for Snowdonia National Park
Severe wind chill. Snow showers, will become persistent later. Hill fog.
How windy? (On the summits)
North or northwesterly, perhaps a lull, but for periods risk 35 to 50mph high tops.
Effect of the wind on you?
Prepare for difficult conditions and severe wind chill on higher terrain.
How Wet?
Snow showers, persistent later.
Showery, with snow or sometimes hail, falling to lower slopes. Most frequent precipitation on northern mountains in Snowdonia. Snow likely to set in from the east during the afternoon.
Cloud on the hills?
Fairly extensive
Often covering higher slopes above 700-800m, with patches of cloud briefly lower around precipitation. Occasional higher breaks mostly toward mid-Wales. In persistent snow later in day, cloud widely extensive on the hills.
Chance of cloud free summits?
30%, lowering to 10% in persistent snow.
Sunshine and air clarity?
Brief glimpses of sun. Visibility varied, sometimes very good, but appalling in snow and cloud.
How Cold? (at 900m)
-4C, may rise marginally. But feeling closer to -20C in direct exposure to strongest winds.
Freezing Level
Terrain frozen into valleys in morning. Rising to 400-600m.
Viewing Forecast For
Snowdonia National Park
Saturday 5th December 2020
Last updated
Thursday 3rd December 2020 at
4:25 PM
How windy? (On the summits)
Easterly, 15 to 25, perhaps 30mph.
Effect of the wind on you?
Walking impeded, risk sometimes arduous on high tops. Significant wind chill.
How Wet?
Generally dry
Rare snow flurries.
Cloud on the hills?
May be very little
Patches of cloud capping higher tops at times. Risk of some low level freezing fog banks, most likely east and mid-Wales.
Chance of cloud free summits?
70%
Sunshine and air clarity?
Occasional sun, mostly west. Visibility very good in places, but locally reduced around cloud banks.
How Cold? (at 900m)
-3C
Freezing Level
Terrain widely frozen. Partial thawing in sunlight up to about 500m.
Viewing Forecast For
Snowdonia National Park
Sunday 6th December 2020
Last updated
Thursday 3rd December 2020 at
4:25 PM
How windy? (On the summits)
Low confidence in detail: North to northwest 10-15mph.
Effect of the wind on you?
Mostly small.
How Wet?
Risk snow showers, rain lower slopes.
Clusters of showers may give snow, rain below 500m, on and off for a few hours. Much uncertainty over this though, may amount to very little and be often dry.
Cloud on the hills?
Extensive
Extensive cloud will very likely cover the hills. Bases varying, but often though the day to lower slopes.
Chance of cloud free summits?
20%
Sunshine and air clarity?
Mostly cloudy. Visibility fairly murky and poor or very poor in snow/rain.
How Cold? (at 900m)
Around -1C
Freezing Level
Around 700-800m.
Planning Outlook
Cold weather patterns are likely to prevail well into December. A period of constant freeze, at least on the Scottish Munros, but often near or below zero on many lower summits across Britain. Upland terrain becoming extensively snow covered as bands of precipitation circulate slowly around low pressure - substantial snowfalls likely across many uplands, and snow may well lie for periods to lower slopes. Wind speed and direction will vary considerably, occasionally gale force. An east or northeasterly common across northern Britain.