Rain or showers are expected through much of Sunday and Monday, and will merge into periods of heavy and persistent rain over high ground.
40 to 50 mm of rain is likely to fall quite widely, and a few places may see 90 to 120 mm during this period.
The largest totals are most likely across higher parts of Cumbria and Lancashire.
The heavier rain should ease away from Scotland and Northern Ireland on Monday morning and from remaining areas on Monday afternoon.
Strong winds will be an additional hazard across Northern Ireland, northwest England and southwest Scotland, with gusts of 50 mph in exposed places.
What to expect
- Flooding of a few homes and businesses is likely
- Bus and train services probably affected with journey times taking longer
- Spray and flooding on roads probably making journey times longer
- Some interruption to power supplies and other services likely