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Thunderstorm warnings have been issued for parts of the UK, as a plume of heat looks set to make Monday the hottest day of the year so far.

The Met Office has issued two yellow thunderstorm warnings which affect Northern Ireland, northern England and Scotland tonight and into Monday morning.

Further south where it is likely to be dry, temperatures will be even higher than Sunday.

This sudden change in our weather is partly due to Tropical Storm Debby, which brought flooding to the eastern United States.

Debby drenched a number of historic southern US cities earlier this week.

The storm then swept quickly north to eastern Canada, bringing the wettest day on record to Montreal.

Having weakened considerably, the remnants of Debby are now in the north Atlantic.

As well as bringing heavy rain Debby pushed very warm air to higher latitudes. This has changed the position of the jet stream with impacts being felt here in the UK.

Downstream in the Atlantic the jet stream pattern has changed from straight to buckled (or more amplified). With the jet stream positioned to the north-west of the UK, very hot and humid air is being drawn up very quickly from Spain and France.

But it will not be hot for all of us.

The highest temperature of the year so far is 32C, recorded in London at the end of July. That is expected to be exceeded on Monday.

Sunday was a very warm day but temperatures in some parts of England will be even higher on Monday.

Much of the Midlands, Lincolnshire, East Anglia and south-east England will be hot and humid with temperatures reaching 30C or more.

The temperature in Cambridgeshire could reach 34 or 35C - easily the hottest day of the year.

A yellow heat-health alert issued by the UK Health Security Agency for the Midlands and southern England will be in place until Tuesday morning.

It is not going to be hot everywhere. Northern and western areas of the UK will be cooler on Monday.

In Northern Ireland the overnight storms will soon move away on Monday morning. The heavy rain, frequent thunder and lightning and large hail will sweep across Scotland and parts of northern England in the morning but clear away on Monday afternoon.

To the south the risk of storms is very much lower.

Tuesday will still be very warm in East Anglia and south-east England, with temperatures up to 27 or 28C. But next week the jet stream pattern in the Atlantic will straighten again and we will be back to more changeable weather with temperatures nearer normal.

The hot weather will be pushed further east across Europe and the whole of western Europe will turn cooler. The prolonged spell of hot weather in Spain will even come to an end.

We've seen a few of these "heat spikes" this summer and there still could be more to come.

I've noticed over many years of presenting the national weather forecast that it used to be the case that we needed three or four days of dry weather to lift the temperature to 30C.

Are things changing and these temperature rises happening more rapidly?

It is difficult to quantify a shift like this, but it could be that we are seeing another impact on our weather patterns as a result of climate change.