REELING IN THE YEARS - Storm Carmen, 10-11 November 2010

WEATHER ALERT issued by TMT's Peter O'Donnell at 5.30pm GMT:

I think it's going to hit full force, no downgrades, and there should be a weather warning out for Northern Ireland.

Would be quite confident of peak gusts at Aldergrove near 65 kts and possibly 70. Some more exposed places could see 80 in NI. As to the wind speeds in Donegal and Connacht, I just don't want to see any further signs of intensification because we're probably at the thresh-hold of significant damage now, unless the models are just totally off on this storm, it has all the signs of peaking at 10W and 1500h which would suggest wind gusts to at least 85 kts at Belmullet and possibly 90 kt at Malin Head. The higher these go, the more widespread the damaging 70-kt gusts elsewhere would become.

At this point I would be assuming the higher end of predicted forecast wind speeds and assessing what could come loose or fall over, get the cars into safe places where they won't get hit by debris or trees, and then if you get through unscathed, it's a good preparation for an even worse windstorm in the future. Almost all the big ones have a westerly component, this one should peak with winds at about 250 deg to 270 deg which is WSW to W.

I'm going back to look at more data but the one point I wanted to make about intensity is not to be too concerned about filling or rising central pressures after 15z, this would be normal for a storm of this intensity, it can't sustain the mid-940s over land but the storm is a process rather than a point event, and there is a lag time between minimum central pressure and strongest winds. The main point is that the track being slightly south of due east, the strongest winds in the 20W sector need to be around 56 N to come across the northern half of Ireland at about 54 N later on. It already appears that the models are verifying, the 12z maps are almost identical to their 24h model targets. When I return in a while, I am going to have an exact location for the centre and an intensity estimate based on any available data.

UPDATE from Peter O'Donnell at 00:00, Thursday, 11 November

The south coast would be marginal for damaging wind gusts, I am going to speculate here but peak wind gusts recorded tomorrow afternoon will likely be in this sort of range:

CORK 60 kt
INLAND 55 kt
DUBLIN 65 kt

When I say "inland" I basically mean any station not listed above that's inland, but some of them seem a bit less exposed than others. Your local situation could be estimated from that list.

There will be very large battering storm waves on the west coast. I hope anyone planning to observe the storm will take all precautions and not expose yourselves to danger from extreme waves.

The situation ranges from very windy with moderate damage potential north to quite windy with limited damage potential south. There again, if you live in a deep river valley running north-south somewhere in northern Ireland, probably won't feel much more than 45 kts peak, but if you're on a hill in the south could see 65 kts. So your exposure is also important as well as the region you're living in.

Every storm has its own irregular features so there will be an element of nowcasting to this, and some of the wind potential will be contained in any squally shower bands that form -- you can anticipate that these might tend to come in through gaps in the topography and quite often north Clare and Galway get hit by these, so would stress that Clare is just about as much at risk of damaging wind gusts as Connacht. Often the max winds in these storms stay in the range of 964 to 976 mbs rather than closer to the storm centre. But given the track I think Malin Head will win the top gust prize.

One other thought, be aware that there will be a secondary wind peak from the front coming through late tonight, so if you notice gusts to say 40 kt then they die off to the 30 kt range, that won't indicate a weakening of the storm, we're expecting that brief weakening of the wind right after the frontal passage and the first part of the clearing trend. Winds will gradually ramp up as the stronger gradient near the low centre approaches. Would predict that the strongest winds will be 3-6 p.m.

Pictures of Storm Carmen (11, Nov 2010) taken by TMT readers from around Ireland. Click on images for a larger view.

Uprooted tree near Killybegs, County Donegal by Pangea

Achill Island, County Mayo by Ian Carruthers

Salthill, Galway by Fiona Gavin

Nightime falls over a stormy West Clare. Pic Tom Clifford

Pic of wind damage from naughto in Castlebar, County Mayo
Pics from Achill Island, Co Mayo, by Winger_PL and Ian Carruthers (TMT)

Storm System At 3.18PM

Wind damage in Athenry, County Galway. Pic by Stephen

Pics from Westport, County Mayo by snow ghost 

Donegal Town pics from Diarmaid

1.43PM Satellite image

Video image from Strandhill, Sligo.

Trough/eye of storm system sweeps eastwards to the north of Ireland at 12.07PM

Lahinch webcam