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Rhybuddion

Mercher 31 Awst Cyhoeddwyd am 07:59

Rhybuddion DU

Rhybudd Tywydd

Cyhoeddwyd gan y Swyddfa Dywydd

Mae'r cynnwys hwn ar gael yn Saesneg yn unig.

Wednesday 31 August

There are no weather warnings in force anywhere in the United Kingdom.

Rhybudd Llifogydd

Rhybudd gan Asiantaeth yr Amgylchedd neu gan SEPA yn yr Alban a Chyfoeth Naturiol Cymru yng Nghymru

Mae'r cynnwys hwn ar gael yn Saesneg yn unig.

Wednesday 31 August

There are no flood warnings in force anywhere in the United Kingdom.

Ynglŷn â Rhybuddion Tywydd y Swyddfa Dywydd

Mae BBC Tywydd yn darparu dau fath o rybudd tywydd gan y Swyddfa Dywydd: Rhybuddion a Rhybuddion Cynnar.

Bydd Rhybuddion yn cael eu cyhoeddi pan disgwylir tywydd garw o fewn y 24 awr nesaf.

Bydd Rhybuddion Cynnar yn cael eu cyhoeddi mwy na 24 awr cyn tywydd garw.

Mae yna dri chategori o ddigwyddiad: Coch, Ambr a Melyn – y mwyaf difrifol yw Coch.

Mae Rhybudd a Rhybudd Cynnar yr un lliw yr un mor ddifrifol â’i gilydd ond eu bod wedi eu darogan i gyrraedd ar adegau gwahanol. Felly, y gwahaniaeth rhwng Rhybudd Coch a Rhybudd Coch Cynnar yw amseriad y digwyddiad.

Pan mae rhybudd mewn grym, ceir gwybodaeth lawn yn Rhybuddion Tywydd y Swyddfa Dywydd (dolen allanol Saesneg).

Ynglŷn â Rhybuddion Llifogydd

Mae’r rhybuddion llifogydd yn cael eu cyhoeddi gan Asiantaeth yr Amgylchedd, Scottish Environment Protection Agency a Chyfoeth Naturiol Cymru, a’u hanfon at Ganolfan Dywydd y BBC. Yna rydyn ni'n cyhoeddi crynodeb o rybuddion wedi eu seilio ar y wybodaeth ddiweddaraf sydd ar gael. Pan mae rhybuddion llifogydd difrifol yn cael eu rhyddhau, bydd rhain yn cael pwyslais ar ddarllediadau teledu.

Dysgwch mwy am Rybuddion Llifogydd

Mae yna nifer o ffyrdd y gallwch chi ddarganfod os yw eich ardal chi mewn perygl o lifogydd. Mae Asiantaeth yr Amgylchedd, Scottish Environment Protection Agency a Chyfoeth Naturiol Cymru yn diweddaru eu rhybuddion 24 awr y dydd trwy rif Floodline.

Floodline - 0345 988 1188

Rhagolwg Misol

Llun 29 Awst Cyhoeddwyd am 10:00

Rhagolwg Misol

Mae'r cynnwys hwn ar gael yn Saesneg yn unig.

Crynodeb
A difficult forecast...

Hurricane Gaston is way out in the Atlantic at the moment, but it is expected to move towards the north of the Azores by Sunday 4th September. By that time it should be a weakening feature, going from a tropical to an extra-tropical storm, and it is that transition which the various forecast models are having trouble with. Different models are doing different things, which means that confidence in Gaston's previous pattern is quite low for the first part of the forecast. Another tropical depression now forming in the west Atlantic will push more energy and moisture north and this will cause further problems for the forecasting models. However, there is some suggestion of a broadly westerly flow dominating, leading to a northwest / southeast split with the strongest winds and most of the rain in the northwest.

Llun 29 Awst—Sul 4 Medi
Autumn starts on a positive note

Climatological autumn starts on the 1st September and there should be a good deal of dry and bright weather to go with it. The best of that is expected in the southeast of the UK, where it will be quite warm with light winds for most of the time. The northwest of the UK is more likely to see some rain at times, that may well arrive on a keen breeze. Some rain is likely in the northwest late on Monday and late on Tuesday, maybe some showers lingering into Wednesday. A more active band of rain is expected to come in from the Atlantic by the end of the week. That will move south and east into the weekend but weakening as it does so not much rain in the southeast. Brighter but more showery weather will follow with most of the showers in the northwest.

Llun 5 Medi—Sul 11 Medi
A warm spell for some.

Ex-Gaston does not look like it will have direct impact on our weather but more of a remote influence. It looks like it will be pushing some warmer air our way. The most likely scenario is to see pressure rising across the south of the UK with low pressure to the north, maintaining the west or southwesterly air flow.
It looks like quite a warm spell will develop under the high in the south with the highest temperatures in the southeast, temperatures further north and west look nearer the norm.
Some parts of the north and west could see a bit more rain than you might expect, amounts should be closer to normal elsewhere.

Llun 12 Medi—Sul 25 Medi
A mobile westerly?

While confidence in the detail is quite low the most preferred solution at this stage is to keep a mobile westerly going but with uncertainties associated with any tropical developments in the Atlantic.
The pressure pattern will probably be quite similar with high pressure to the south and lower pressure to the north. In this sort of set up you would expect, the strongest winds and most of the rain in the northwest and it looks like Northern Ireland may well see more than average amounts of rain while East Anglia may well be a lot drier than normal.
It looks like it'll stay quite warm for many with temperatures above the average but in Northern Ireland and northern Scotland we'll be nearer to normal.

Wythnos nesaf

We'll take a look at the last few days of September and the first weekend of October. Will the warmth last?

Rhagolygu Misol
Mae rhagolygu’r tywydd hirach nag wythnos ymlaen llaw yn her i hyd yn oed yr arbenigwr tywydd mwyaf profiadol. Mae modelau rhagolwg rhifiadol y tywydd gan y Swyddfa Dywydd a'r Ganolfan Ewropeaidd ar gyfer Rhagolygon Tywydd Ystod-Canolig (ECMWF) yn cael eu rhedeg nifer o weithiau'r mis (a'r tymor) i ddod, er mwyn dyfalu sut dywydd fydd yn effeithio ar y DU.

Diweddariad nesaf am 10:00, Llun 5 Medi

Crynodeb

Mercher 31 Awst Cyhoeddwyd am 14:54

Crynodeb

Mae'r cynnwys hwn ar gael yn Saesneg yn unig.

Dry and fine for most overnight.
This Evening and Tonight

Dry with clear spells and light winds for most, with a few mist or fog patches forming late in the night. Across northern Scotland it will be a little breezier with some showers during the first half of the night.

Thursday

Across northern and northwestern parts it will turn cloudier in the morning, with some outbreaks of rain spreading from the west. Elsewhere it will be dry with warm sunny spells.

Outlook for Friday to Sunday

Some brightness on Friday, but also rain or showers for most. Many places starting fine on Saturday, but rain, heavy at times, spreading from the west. Remaining unsettled on Sunday.

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