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Serious flooding is possible across many parts of the UK as milder temperatures thaw snow and rain moves in, forecasters have warned.

Parts of Carmarthenshire, Powys, Gwynedd and Norfolk have flooded and a Met Office yellow warning for rain is in force for much of the UK.

Eighty-one flood warnings and 323 alerts are in place in England and Wales. Scotland has seven warnings.

Forecasters say Sunday will see a mix of sunny spells and blustery showers.

The Met Office said heavy rain across much of the country, combined with fairly rapid snow melt, was likely to lead to localised surface water and river flooding.

Western Scotland and Cumbria saw the heaviest rain on Saturday night. Wales, central and south-west England are expected to be the worst-hit areas on Sunday morning, with at least 1in (2.5cm) of rain expected to have fallen by mid-morning.

There are flood warnings in place in East Anglia, south-west England, the Midlands, north-east England, north-west England and Wales.

The Environment Agency said emergency teams were out in these areas checking "high priority defences" to make sure they were working.

Norfolk Police have reported flooding caused by melting snow and ice, which has closed a number of roads in the area.

In Wales, there has been flooding in Powys, Gwynedd and Carmarthenshire.

Environment Agency spokesman Innes Thomson told BBC News: "The message is that there's wet weather all over the country, we've already got flooded fields, we've got localised flooding, we've got high ground water and we've got spring tides this week coming.

"So we've actually got a complete cocktail of issues and concerns for us to keep an eye on."

Spring tides occur when the sun and moon are aligned, so their gravitational pull is combined - leading to especially high, high tides and low, low tides.

The seven flood warnings issued by the Scottish Environment Protection Agency (Sepa) include the Scottish Borders, Whitesands in Dumfries and Galloway and parts of central Scotland.

The BBC weather centre said much of the rain would clear eastwards through Sunday.

BBC forecaster Laura Gilchrist said Sunday would see sunny spells and blustery showers - with the heaviest in the west and north. The wind would be brisk and there was also a risk of hail and thunder.

Moving into the night, the showers would leave off, but Monday would see wet and windy conditions for most.