Met Éireann’s current orange weather warning for several countries is the "first ever" in Ireland for high temperatures, Evelyn Cusack says.
The two warnings - status orange for Cavan, Monaghan, south Leitrim, Roscommon, Longford and Westmeath and status yellow for the rest of the country - remain in place until Friday.
Temperatures have today surpassed 30 degrees in some areas, as the heatwave continues.
— Met Éireann (@MetEireann) July 21, 2021
A warm air mass that originated in the Tropics is partially responsible for the hot weather - and helps explains why temperatures are remaining high even after the sun goes down.
Ms Cusack - head of forecasting at Met Éireann - told The Hard Shoulder temperatures are high right across the country.
She said: “It’s 30.5 degrees in Longford, Roscommon and eastern parts of Mayo. Widely, it’s 28-29 degrees around the country. In Dublin, it’s 24, which isn’t bad at all.
“The Irish Sea temperature is quite high compared to normal - it’s about 18-19 degrees, and normally it’s about 16 degrees. It’s a good time for a dip.
“We have yellow and orange level warnings out for the first time ever for heat. The thing about 2018 was it was warm, dry and sunny for a prolonged period… the nights were refreshing.
“The reason we have warnings [now]… is the nighttime temperatures. I know a lot of people are finding it uncomfortable - if you’re anyway ill at all, it’s terrible because the body can’t really recover.”
She noted the warnings are more intended as a “health warning” to people.
While orange and even red warnings have been issued for snow / icy weather before, this orange warning is the first for high temperatures.
Overnight temperatures tonight and tomorrow will stay at around 20 degrees in some areas - with temperatures still as high as 26 degrees between 10pm and midnight.
Ms Cusack advised people to open the windows on the cooler, north-side of the house in the evenings to let colder air in.
Tomorrow and Friday will remain very hot and sunny.
It will stay warm after that, but the extreme heat will start to ease over the weekend - with a chance of some showers from late Friday.
While summery conditions will continue, Ms Cusack says the weather will be "more normal" next week.