Met Office: Bannau Brycheiniog: forecast cloud

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Sefyllfa cyffredinol Dydd Llun

Starting dry but rain soon spreading from the west, with some heavy bursts by late morning. Hill fog. Rain clearing from the west by midafternoon. Windy, with gales, easing somewhat later.

Peryglon	Risgiau	Eglurhad
Stormydd eira	No Risk
Eira trwm	No Risk
Gwyntoedd nerth storom	Low	A few gusts of around 60 mph likely.
Tymhestloedd	High	Southwesterly winds of 40 to 50 mph at first, easing somewhat later.
Effaith oeri difrifol	No Risk
Niwl hirbarhaol ac eang dros y bryniau	High	Associated with rain during the day.
Stormydd o daranau	Low	Low risk associated with the rain during the day.
Glaw trwm di-baid	Low	Some heavy rain likely late morning and early afternoon.

Peryglon

Risgiau

Eglurhad

Stormydd eira

No Risk

Eira trwm

No Risk

Gwyntoedd nerth storom

Low

A few gusts of around 60 mph likely.

Tymhestloedd

High

Southwesterly winds of 40 to 50 mph at first, easing somewhat later.

Effaith oeri difrifol

No Risk

Niwl hirbarhaol ac eang dros y bryniau

High

Associated with rain during the day.

Stormydd o daranau

Low

Low risk associated with the rain during the day.

Glaw trwm di-baid

Low

Some heavy rain likely late morning and early afternoon.

Crynodeb a thebygolrwydd gwlybaniaeth Dydd Llun
O'r Wawr hyd 0900	0900 hyd 1200	1200 hyd 1500	1500 hyd Machlud
Light rain	Heavy Rain	Heavy Rain	Sunny intervals
60%	90%	90%	10%

Crynodeb a thebygolrwydd gwlybaniaeth Dydd Llun

O'r Wawr hyd 0900

0900 hyd 1200

1200 hyd 1500

1500 hyd Machlud

Light rain

Heavy Rain

Sunny intervals

60%

90%

10%

Rhagolygon y tywydd manwl ar gyfer y mynyddoedd: Bannau Brycheiniog

Dydd Llun
Dydd Mawrth
Rhagolygon

Dydd Llun

Tywydd

Dry at first, with occasional hill fog, but outbreaks of rain will soon spread from the west, with more general hill fog developing. Some of the rain is likely to be heavy and southwesterly winds will be strong to gale force. Clearer, drier conditions will then follow from the west by around the middle of the afternoon, with winds veering more westerly and easing somewhat.

Gwelededd

Moderate or good, occasionally poor in rain and very poor in fog.

Niwl dros y bryniau

Patches above 300 metres at first. Becoming persistent above 300 to 400 metres through the morning, with patches below this level in rain. Clearing from the west later in the day.

Gwyntoedd uchaf uwch ben 400m

Southwest 55 to 60 mph, veering westerly early afternoon and easing to around 30 mph.

Tymheredd

Dyffrynnoedd	Plus 6, rising to a maximum of Plus 10 Celsius.
800 m	Plus 4, rising to Plus 8 Celsius.
Lefel rhewi	Well above the Peaks.

Dydd Mawrth

Tywydd

Dry with variable amounts of cloud and some valley fog patches. Perhaps some brightness at first but cloud becoming widespread by late morning, with rain developing across the area, along with hill fog. Becoming windy.

Gwelededd

Mostly good, becoming moderate to poor in rain, and very poor in any hill fog.

Niwl dros y bryniau

Hill fog becoming widespread in the south of the area and patchy in the north, mainly above 400 metres but perhaps lowering at times to 200 metres in the south.

Gwyntoedd uchaf uwch ben 400m

Southerly or southeasterly 45 mph

Tymheredd

Dyffrynnoedd	Plus 2 Celsius, rising to plus 8 Celsius.
800 m	Plus 4 Celsius
Lefel rhewi	Well above the peaks

Rhagolygon

Dydd Mercher

Detail uncertain but probably a cloudy day generally, with rain at times and with occasional hill fog, perhaps becoming extensive and persistent over the higher ground. Southerly winds moderate, perhaps becoming fresh or strong at times.

Dydd Iau

A lot of cloud and some further outbreaks of rain likely but probably less wet than on Wednesday, although still with the risk of extensive and persistent hill fog. There is also a risk of more widespread and heavier rain, with increasing winds, spreading across from the south towards dusk.

Dydd Gwener

Staying windy with a risk of gales. Occasional showers or longer outbreaks of rain, some of it heavy. Hill fog at times, especially in the south and west of the area.