The first real storm of the season is brewing up in the Atlantic as we speak and will bring some heavy rain and damaging winds right across the country this evening and tonight. This one, however, could be particularly dangerous if you’re out and about, even more dangerous than a similar storm later in the season. Why? Read on.
We all know we’ve had an easy time of it during September, but last Thursday night and Friday marked the transition into proper autumn weather. Tonight will be Stage 2 of the process.
A large area of low pressure covers most of the north Atlantic and is generating a strong westerly flow at all levels. A strong jet streak is interacting with, and deepening, a small low out to our southwest. This will move towards us this afternoon.
The west and southwest will start to see gale-force southerly winds from late afternoon, with storm-force gusts up to 120 kph. Föhn conditions will develop and bring enhanced downslope hurricane-force gusts on the leeward (northern) side of high ground. Tonight’s flights in and out of Shannon and Cork airports could be affected, so check for the latest updates.
The swathe strong winds and heavy rain will move eastwards across the country unabated, clearing the east coast by sunrise, just in time for the morning rush at Dublin and Belfast airports. Dublin could see some severe Föhn gusts off the mountains to the south. Behind the front winds will ease and turn westerly, feeding in a cooler showery setup.
What makes this storm particularly dangerous is the fact that most trees are still in full leaf. This allows the trees to catch the maximum force of the wind, so trees that may withstand a similar storm when bare may not stick it out tonight. The leaves that do come off the trees could block drainage systems, so spot flooding could add to the problem. Bear this in mind if out and about tonight and postpone your trip if possible.
The outlook is for the parent low to remain near us for the forseeable future, so expect more wet and windy conditions on and off throughout the month.
Images from http://www.meteociel.fr