Her response follows criticism of a full colour map which was published by Met Éireann over Christmas to indicate a status orange storm warning across the Republic of Ireland.
However the same map left the six counties in Northern Ireland white, with no information.
In a post viewed by almost 300,000 people online and liked by over 1,000 people, including RTÉ’s Rachael English, one poster called the map “ridiculous.”
The commentator said: “Hi Met Éireann, it’s kind of ridiculous you don’t include the six counties that make up the North/NI when you are doing maps. Letting us know isn’t going to ‘unpartition’ the place and I’ve got a feeling this constitutes a grievous infringement of the Good Friday Agreement.”
Another commentator asked: “Is it snowing up there? Why is the map white?”
While another commentator complained of visiting relatives to Northern Ireland and said it would have been easier to give up its “nonsense” and “show the weather for the whole island.”
In response, this weekend Ms Donnelly rubbished the criticism and slammed the idea that Met Éireann is “cutting out” the six counties from its weather updates.
She told the Sunday Independent that Met Éireann issue weather forecasts for the whole of the island of Ireland but “responsibility for warnings for the jurisdiction in question is with the UK Met Office.”
She said “Met Éireann do display the warnings that the UK Met Office issue for Northern Ireland – the fact that that region is showing up in white on the map means that there were no warnings in effect in these counties at this time.”
Ms Donnelly added that she “fully understands the sensitivities” around the partition between The North and the Republic of Ireland but points to “the nature of posting on the platform X” which whipped up the controversy.
She stressed that Met Éireann operates in a collaborative manner with the UK Met Office and they enjoy “an excellent professional working relationship.”
“It’s absolutely nothing to do with partition other than that the UK Met Office have responsibility for the issuing of weather warnings for Northern Ireland. Met Éireann issue warnings for the rest of the island. Met Éireann issue weather forecasts for the whole of the island, this map is specifically for warnings in operation at that specific time.”
In the past, the BBC in London has been accused of treating the Republic of Ireland as “some kind of North Korea” for refusing to name key cities on its weather map.
Critics suggested it follow the example of ITV, which regularly shows cities across Ireland on its weather maps.