Parts of south Leinster and Munster are nearing agricultural drought, says Met Éireann meteorologist Paul Downes.

Speaking to the Irish Farmers Journal on Friday, Downes said: “There is the potential for Leinster and Munster to have agricultural drought over the coming days.”

On the potential of hotter and drier weather than usual continuing for the weeks and months ahead, he said farmers “would want to prepare for the worst”.

He described how Met Éireann uses soil moisture deficit measurements to define an agricultural drought and said that any farm land with a soil moisture deficit of 75mm qualifies.

Soil moisture deficit for Thursday 11 August. Note the high figure of 74mm (which has subsequently hit 78mm) at the Dublin Airport station, as well as figures of 63mm and 70mm in the southeast.

Soil at Met Éireann’s Dublin Airport weather station has already hit this mark with a moisture deficit of 78mm.

However, Downes acknowledged that this soil is traditionally always drier anyway. But this does mean that farm land near to Dublin Airport is likely already under agricultural drought conditions.

The 75mm soil moisture deficit barrier has not been passed at any other Met Éireann weather station, with the latest soil measurements in the southeast reading a deficit between 60mm and 75mm.

However, the meteorologist said that this doesn’t mean there aren’t pockets of land, particularly in the southeast, which already meet the agricultural drought criteria.

Drought

An agricultural drought differs from a general drought and Ireland is not yet under these conditions, according to Downes.

He said the parameters for general drought are “a dry spell of 15 days with less than 1mm of rainfall”.

As Ireland had some light rain and precipitation at the start of August, the country does not yet qualify as having general drought conditions.

However, regardless of this, Downes said “from an agricultural point of view, grass growth is severely impacted” by the current hot and dry weather.

Outlook

The Met Éireann meteorologist said that while rain is forecast for Sunday, there will be a knock-on weather effect of the current heatwave conditions.

“If ground is dry, you tend to get less rainfall,” he said. However, he did note that there will be “potentially more substantial rainfall next weekend”. Although, he said Met Éireann’s confidence in this is low.

Even if substantial rainfall does come, Downes said the dry soil will have a much-reduced ability to absorb this, leading to a lot of run-off.

Long term

On the potential of dry and hot weather continuing over the coming weeks and months, Downes said “farmers would want to be prepared for the worst”.

While noting that it is difficult to forecast long-term weather conditions and that the confidence in these is low, from a climatology perspective, he said the “broad indicators” are “pointing in the direction” of sustained hotter and drier than usual weather ahead.

“A lot of the models are drier for the next couple of months,” he said.

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