Parts of the UK have been under thunderstorm warnings since a plume of heat looked likely to make Monday the hottest day of the year so far.
Two yellow thunderstorm warnings issued by the Met Office impact Northern Ireland, northern England, Scotland tonight and into Monday morning.
Further south, where it is probably dry, temperatures will be much higher than Sunday.
Tropical Storm Debby, which caused flooding in the eastern United States, is partially responsible for this abrupt change in our temperature.
Debby's jet stream
Earlier past week Debby soaked several historic southern US cities.
Then the storm moved swiftly north to eastern Canada, producing Montreal's wettest day ever.
Now in the north Atlantic, Debby's weakening remains are barely visible.
Debby also drove very warm air to higher latitudes in addition to producing copious rain. This has shifted the jet stream's position such that effects are felt here in the United Kingdom.
From straight to buckled—or more amplified—the jet stream pattern has shifted downstream in the Atlantic. Very hot and humid air is being pushed up from Spain and France as the jet stream points north-west of the UK.
But for none of us will it be hot.
It's going to get how hot?
Recorded in London at the end of July, 32C is the highest temperature of the year thus far. On Monday, that is supposed to be surpassed.
Although Sunday was a quite pleasant day, temperatures in some areas of England will be much higher on Monday.
Temperatures in much of the Midlands, Lincolnshire, East Anglia, South-east England will be hot and muggy, reaching 30C or above.
Cambridgeshire's temperature can soar to 34 or 35C, easily the hottest day of the year.
The UK Health Security Agency's yellow heat-health notice for the Midlands and southern England will be in effect till Tuesday morning.
Not everyplace is going to be hot. Monday will find the northern and western parts of the United Kingdom colder.
The overnight storms in Northern Ireland will quickly fade on Monday morning. In the morning, the heavy rain, frequent thunder and lightning, and big hail will wash over Scotland and some of northern England; then, on Monday afternoon, they will clear away.
Storms are somewhat less likely to strike the south.
The heat will stay how long?
With temperatures up to 27 or 28C, Tuesday will still be somewhat warm in East Anglia and South-east England. However, the jet stream pattern in the Atlantic will straighten once more next week, so returning more changeable weather with temperatures close to normal.
The scorching weather will be driven further east across Europe, while western Europe will turn colder overall. Even Spain's protracted hot streak will eventually come to end.
Although we have witnessed a few of these "heat spikes" this summer, more could be in store.
Over many years of displaying the national weather prediction, I have seen that it used to be the case that we needed three or four days of dry weather to raise the temperature to 30C.
Are things shifting and more fast temperature increases occurring?
Although it is impossible to measure a change like this, climate change could be causing yet another effect on our weather patterns.
Rajesh Kumar
Parts of the UK have been under thunderstorm warnings since a plume of heat looked likely to make Monday the hottest day of the year so far.
Two yellow thunderstorm warnings issued by the Met Office impact Northern Ireland, northern England, Scotland tonight and into Monday morning.
Further south, where it is probably dry, temperatures will be much higher than Sunday.
Tropical Storm Debby, which caused flooding in the eastern United States, is partially responsible for this abrupt change in our temperature.
Debby's jet stream
Earlier past week Debby soaked several historic southern US cities.
Then the storm moved swiftly north to eastern Canada, producing Montreal's wettest day ever.
Now in the north Atlantic, Debby's weakening remains are barely visible.
Debby also drove very warm air to higher latitudes in addition to producing copious rain. This has shifted the jet stream's position such that effects are felt here in the United Kingdom.
From straight to buckled—or more amplified—the jet stream pattern has shifted downstream in the Atlantic. Very hot and humid air is being pushed up from Spain and France as the jet stream points north-west of the UK.
But for none of us will it be hot.
It's going to get how hot?
Recorded in London at the end of July, 32C is the highest temperature of the year thus far. On Monday, that is supposed to be surpassed.
Although Sunday was a quite pleasant day, temperatures in some areas of England will be much higher on Monday.
Temperatures in much of the Midlands, Lincolnshire, East Anglia, South-east England will be hot and muggy, reaching 30C or above.
Cambridgeshire's temperature can soar to 34 or 35C, easily the hottest day of the year.
The UK Health Security Agency's yellow heat-health notice for the Midlands and southern England will be in effect till Tuesday morning.
Not everyplace is going to be hot. Monday will find the northern and western parts of the United Kingdom colder.
The overnight storms in Northern Ireland will quickly fade on Monday morning. In the morning, the heavy rain, frequent thunder and lightning, and big hail will wash over Scotland and some of northern England; then, on Monday afternoon, they will clear away.
Storms are somewhat less likely to strike the south.
The heat will stay how long?
With temperatures up to 27 or 28C, Tuesday will still be somewhat warm in East Anglia and South-east England. However, the jet stream pattern in the Atlantic will straighten once more next week, so returning more changeable weather with temperatures close to normal.
The scorching weather will be driven further east across Europe, while western Europe will turn colder overall. Even Spain's protracted hot streak will eventually come to end.
Although we have witnessed a few of these "heat spikes" this summer, more could be in store.
Over many years of displaying the national weather prediction, I have seen that it used to be the case that we needed three or four days of dry weather to raise the temperature to 30C.
Are things shifting and more fast temperature increases occurring?
Although it is impossible to measure a change like this, climate change could be causing yet another effect on our weather patterns.