The remnants of subtropical storm 'Debby' is expected to bring heavy rain to Northern Ireland.
Met Office meteorologist Emma Smith said although Saturday will be 19 degrees in Northern Ireland and "very humid" we will feel the effects of a storm from the Atlantic.
"It will be very humid on Saturday, as the rain falling is coming from the Tropics," she said.
"And it is bringing with it a humid and muggy feel.
"This is the remnants of subtropical storm 'Debby' from the Atlantic - which will be heavily modified by the time it gets to you.
"On Saturday the remnants of the storm are meeting an area of low pressure - and that is what is bringing the rain.
"But because it has comes from a tropical place it is bringing muggy and humid air with it."
Meanwhile this afternoon (Thursday), Ms Smith said everyone should expect to see "showers to be quite scattered" and "some heavy outbreaks for most in Northern Ireland".
"Temperatures tonight will get down to 9 or 10 degrees which is a fresh night," she said.
She added that Friday will see a similar mix of "sunshine and showers, with some on the heavy side".
"There is a risk of hail in there as well. As we head into the afternoon it will become dry and temperatures will be 16/17 degrees. Meanwhile there is a light wind of 10-15 mph."
She said Sunday was set to be "the best day of the week for Northern Ireland" and 21 degrees "with more sunshine around".
"Basically Northern Ireland and western Scotland are sandwiched between two bands of rain so you could see some showers coming through at times," she added.