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Snowdonia: forecast cloud
Saturday, 18 May 2013: dawn to dusk
Printable view Forecast issued: 1731 on Saturday, 18 May 2013
Overview for Sunday
Dry with sunny periods throughout the day once any early mist and valley fog has cleared.
| Hazards | Risk | Explanation |
|---|---|---|
| Blizzards | No Risk | |
| Heavy snow | No Risk | |
| Storm force winds | No Risk | |
| Gales | No Risk | |
| Severe chill effect | No Risk | |
| Persistent and extensive hill fog | Low | Occasional hill fog is expected across the summits, although it may become more extensive at times. |
| Thunderstorms | No Risk | |
| Heavy persistent rain | No Risk | |
| Strong Sunlight | Medium | Sunny periods likely throughout the day bringing a risk of sunburn. |
key to hazards and forecast content
| Dawn to 0900 | 0900 to 1200 | 1200 to 1500 | 1500 to dusk |
 Mist |
 Sunny intervals |
Sunny intervals |
 Sunny |
| 0% | 0% | 0% | 0% |
Detailed mountain weather forecast: Snowdonia
Sunday
Weather
Light winds and clear periods during the early hours mean that it will be rather chilly at first and there is likely to be some mist and fog in the valleys. This will clear during the first half of the morning and the rest of the day will be dry with sunny periods. Winds will increase and will become northwesterly in the afternoon, and this will make it feel a little cooler again to end the day.
Visibility
Generally good, but only moderate in early morning mist and very poor in hill fog.
Hill fog
Some mist and fog in the valleys at first, then only occasional hill fog above 800 metres during the day.
Maximum winds above 500m
15mph northwesterly in the afternoon.
Temperature
| Valleys | Plus 4 Celsius rising to plus 14 Celsius. |
| 900 m | Plus 5 Celsius. |
| Freezing level | Above the summits. |
Monday
Weather
A much cloudier day than Sunday with only limited brightness, mainly to the south of the National Park. Low cloud will give extensive hill fog on northern slopes, and will be thick enough to produce outbreaks of light rain and drizzle. It will also be a windy day, especially at height, and will feel cold.
Visibility
Generally moderate, but poor or very poor in hill fog and rain.
Hill fog
Extensive hill fog to low levels on northern slopes. Periods of hill fog above 400 metres elsewhere.
Maximum winds above 500m
30mph northerly, becoming 20mph northeasterly by afternoon.
Temperature
| Valleys | Plus 10 Celsius |
| 900 m | Plus 10 Celsius |
| Freezing level | Above the summits. |
Outlook
Tuesday
A rather cloudy day with outbreaks of rain mainly affecting northern parts of Snowdonia. Periods of hill fog are likely. Fresh northerly winds will affect all areas so it will feel cool.
Wednesday
A mixed day of sunny spells and occasional showers. Fresh northerly winds will continue to affect the National Park so it will feel chilly.
Thursday
Strong north or northwesterly winds will continue throughout the day, and it will feel cold at altitude with the freezing level just below the summits. There will be some sunny periods, but scattered showers are likely to develop. Some of these will be heavy with a risk of hail, and perhaps some sleet around the summits.
Observations
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The Enhanced Mountain forecast for Snowdonia has been discontinued. All forecast information for these locations can be found in the standard Mountain forecast above.
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