Britain to enjoy unseasonably warm 27C highs and rare 'tropical night' before being hit by 'weather bomb' with heavy rain and 50mph gusts

Parts of Britain will enjoy unseasonably warm temperatures this afternoon with highs of 27C expected – before the country is hit by a 'weather bomb' tomorrow.Southern and eastern areas of England are basking in a late burst of warmth a month after summer ended, with the mercury up to 7C above average for the time of year.Tonight will also be very warm with a 'tropical night' possible in some locations, when temperatures do not fall below 20C overnight - also very unusual for late September.London is among the areas set for a tropical night, which will be significantly warmer than normal given overnight temperatures this time of year are 7C to 11C on average.But conditions will turn unsettled through the night as a weather front gradually moves from west to east, bringing 1.5in (40mm) of rain and 50mph gusts tomorrow.Meteorologists are tracking a deep area of low pressure in the Atlantic Ocean which is undergoing explosive cyclogenesis, commonly known as a 'weather bomb'.A weather bomb is officially declared when the central atmospheric pressure of a low pressure system rapidly falls by at least 24 millibars within a 24-hour period.Forecasters said the incoming system in the north-east Atlantic is set to fall from 987mb to 955mb in 24 hours – a drop of 32mb, and therefore above the threshold.This morning started widely cloudy in the South, before sunshine develops during the afternoon. The North saw a clear morning which gave way to increasing cloud.Met Office chief forecaster Matthew Lehnert said: 'A deep area of low pressure far into the Atlantic is the primary driver behind the UK's weather over the next few days.'Its first influence will help pull some warmer air over much of the country on Tuesday, with a peak of 27C likely – which is notably warm for the time of year.'A warm night will follow across southern and eastern areas, with minimum temperatures of 19C in places.'By this evening, western areas will turn increasingly wet and windy, with a weather front moving from west to east by the end of the day and through tomorrow.Met Office deputy chief forecaster Steven Keates said: 'As this weather front moves gradually from west to east late on Tuesday and Wednesday, many places will see around 10mm of rain, with in excess of 40mm possible in some isolated spots in south-facing hills in the west.'This period of weather will also see gusty winds, with gusts over 50mph possible, particularly on exposed coasts in the northwest. Large waves are likely to affect some coasts in the west, coinciding with high spring tides.'Thursday and Friday are expected to see further rain and some heavy showers in many areas, although there should be some drier and brighter spells.High pressure will then build over much of the UK this weekend, resulting in a lower chance of rain - with any light showers confined to far north-western areas.Mr Keates added: 'There's a good degree of confidence that high pressure will become more dominant over the weekend with lots of dry and fine weather for many.'Temperatures will generally be around average for the time of year, with this high pressure likely to linger for at least the start of next week.'There had been expectations that the Met Office could name the first storm of autumn this week, but this now appears to be unlikely.The first named storm of the 2026/27 season will be Storm Austen, in the partnership between the Met Office, Ireland's Met Éireann and the Dutch service KNMI.Met Éireann selected the name in honour of Austen Nagle, the Irish Meteorological Service's first director; and for the fifth storm of the season, the weather service celebrated Evelyn Murphy, RTÉ's first woman weather presenter.In Ireland today, Met Éireann issued a series of yellow wind and rain warnings - but is also not expected to name the system as a storm, given there are no orange warnings in place.It comes as much of England remains in drought after a very dry spring and summer that brought successive heatwaves, putting huge pressure on water supplies.While the last month has finally brought some meaningful rain to parched areas, hosepipe bans remain in place with no prospect of being lifted soon.Supercharged El Nino conditions in the Pacific – which affect weather across the world – are set to put the UK at greater risk of a wet and stormy autumn overall.