A weather warning for heavy rain has been issued for the Gwendraeth, Amman, Towy and Swansea valleys.
About 15-30mm (0.6-1.2in) of rain will fall widely, with up to 40-50 mm (1.5-2in) over south-facing high ground, the forecaster said
The weather warning will last until 1pm on Tuesday, November 15, and there is a risk of flooding.
The heavy rain will stretch across southern Powys and over the English border into Herefordshire.
A spokesperson from the Met Office said: “Heavy rain may lead to some flooding and disruption to travel.
“Spray and flooding on roads probably making journey times longer. Bus and train services will probably be affected, with journey times taking longer.
“Flooding of a few homes and businesses is possible.”
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The Met Office added: "Monday evening will see some clear spells, but cloud will quickly build in from the south-west. It will bring spells of heavy and persistent rain that will linger until dawn.
"Tuesday morning will start with overcast skies and spells of heavy rain. Cloud will gradually clear through the afternoon but towards the evening showers will drift in from the south."
⚠️ Yellow Weather Warning issued ⚠️
— Met Office (@metoffice) November 14, 2022
Rain warning for S Wales and southern England
Tuesday 0000 to Tuesday 1300
Latest info 👉 https://t.co/QwDLMg9c70
Stay #WeatherAware⚠️ pic.twitter.com/iDhMoLLckJ
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