A 12-hour warning for southwest Britain and Wales begins at 4 am on Tuesday, forecasting strong winds and heavy rain, with gusts up to 65mph in exposed areas.
From midday on Wednesday, a 48-hour warning will affect Central, Tayside and Fife, Grampian, and Highlands and Eilean Siar, predicting persistent heavy rain.
Rainfall of 30 to 60mm is expected in northern areas, potentially reaching 80 to 120mm over high ground, with rain turning to snow on higher elevations by Thursday and Friday.
The warnings highlight a small chance of flooding for homes and businesses, as well as potential power cuts and road closures, exacerbated by already saturated ground.