Brits will be lashed by torrential downpours with as much as 30mm of rain to fall this morning amid ferocious 70mph winds.
The autumn storm that has swept parts of the country will continue to rage on Monday morning before the mercury plummets as much as 10C, with a near freezing low of 2C by Thursday in some areas.
The Met Office has issued two separate severe weather warnings that remain in place at the start of a new week.
Further gale force winds and torrential rain are set to continue with the warnings running until 10am in some areas of the UK.
For parts of Wales and northern England and Scotland the Met Office said Brits should prepare for several further spells of heavy rainfall which will lead to flooding and travel disruption, forecasters warn.
Further flooding is also expected to strike some homes and businesses, while bus and train services will be affected.
Some regions will also see gale force winds which could be severe in many coastal areas during the early hours of Monday.
Winds will gust quite widely to between 50 and 60mph along coasts, possibly reaching 70mph in the most exposed spots, forecasters said.
Inland gusts are expected to be lower, peaking in the 40s or low 50s mph.
The weather warning for rain is in place until 6am while the warning for wind is in effect until 10am.
And the temperature is expected to plunge in the coming days, with one forecaster predicting a drop of some 10C.
A Met Office forecaster said: "After a wet and windy Halloween with a deep Atlantic low pressure system and damaging winds, it turns colder into the new week."
John Hammond, of weathertrending, said: "The drop of 10C or more will be quite a shock as temperatures tumble after such warm conditions recently.
"Blustery northwesterly winds will make it feel chillier, with snow possible on northern mountains and perhaps to lower levels, with overnight frost possibly becoming more widespread.
"Atlantic fronts are expected to bring rain from the west by the weekend."
UK Weather Forecast
Monday:
A windy day with a mixture of sunny spells and showers, these heavy at times with a risk of thunder in the south. Showers merging into longer spells of rain in the north.
Monday evening:
Showers continuing in the north and west, as well as close to English Channel coasts, whilst dying out inland leaving clear periods and a rural ground frost.
Tuesday:
Showers around coasts in the north and west, else sunny periods, with a scattering of showers developing inland during the afternoon.
Outlook for Wednesday to Friday:
Showers around coasts, but mainly dry inland with sunny spells by day and patchy frost and fog overnight. Becoming fine in south by Friday, but with rain in the north.
