Northern Ireland weather: Hottest day of the year so far
- 22 July 2014
- From the section Northern Ireland
The appearance of good weather in Northern Ireland is something many of us are always happy to see.
After all, we get more than our fair share of cold, wet and windy days.
However, over the last few days temperatures have been on the rise, leading to plenty of bright days - but humid and sticky evenings.
On Monday night, minimum temperatures in Finner, County Donegal and Castlederg, County Tyrone fell to 18.4C and 17C respectively.
These values are close to the average daytime highs for this time of year.
Temperatures have been steadily rising over Northern Ireland over the last number of days and with quite high levels of humidity, this tends to make it feel even warmer.
Daytime temperatures are likely to continue to reach the mid-20s for much of this week across Northern Ireland during the day.
Temperatures have reached 26.1C at the Giant's Causeway, making Tuesday the warmest day of the year in Northern Ireland so far.
This beats the previous top temperature of 25.1C, which was recorded at Derrylin in County Fermanagh in June.
However, the heat may set off a few thundery showers, particularly across western counties.
As the air is humid, it means temperatures will remain well above average at night time too - in the high teens in some areas - and this will make it feel more oppressive and difficult to sleep.
The average daytime temperature for this time of year is around 18C or 19C, and it is possible that some places in the west may not drop much lower than that over the next couple of nights.
Where did the heat come from?
Heat started to build over Spain last week resulting in temperatures reaching the low-40s across the Spanish plateau - 42.9C at Cordoba.
This very warm, humid air moved north into southern parts of the UK and the Republic of Ireland last week, resulting in the Met Office issuing a heat-health alert for some areas of England.
This in itself is quite an unusual event.
The heat generated some severe thunderstorms and resulted in flooding in some areas, including Cork last weekend.
There were over 60,000 lightning strikes recorded in the UK in that period.
The storms, however, did not wash the heat away.
While the heat over Spain is fairly stagnant and the pressure pattern remains such that our air continues to come up from southern latitudes, this hot air is trapped and continues to feed northward into the UK and the Republic of Ireland.
For anything to change, a significant weather system needs to move in from the Atlantic.
This would mean a change in the wind direction - therefore, the supply of hot air from the south would be cut off and instead much cooler, fresher air would move in from the Atlantic.