Storm Ciara - Strong Winds & Potential Snow **TECHNICAL DISCUSSION**

pauldry

Squall in sligo now lashing

Gaoth Laidir

Ciara hasn't deepened in the 6 hours up to 12Z, still 969 hPa just east of New Foundland.





By 06Z tomorrow it will have deepened to only 950 hPa, so not rapidly intensifying, though it did start off as a low way down near Florida during the week.

Gaoth Laidir

ASCAT winds measured at 11:50Z today show 40 knots off the west coast. Belmullet was reporting 35 knots at the time, with a 54-knot gust in the following hour.

The ECM 100-metre winds for the same area at the same time were around 26 m/s (50 knots), which tallies well with the Belmullet and ASCAT figures.





The same ECM chart for tomorrow morning shows 100-metre winds around 6 m/s (12 kt) stronger, meaning about 8 knots higher at the surface. Mace Head could touch mean winds near 50 knots, gusts high 60s.

DOCARCH

At 4pm, Malin Head gusting 106 km/h

Goldfinch8

Has been a very wet afternoon in Mayo. Sheets of driving rain here now.
Pools of water already showing in some fields locally.

Gonzo

very windy here in Meath, not much rain so far today, a few spits of drizzle every few minutes.

Gaoth Laidir

The Met Éireann aviation chart for 18Z shows a 80-knot spot wind at 5000 ft at 52.5N 15W, temperature +6 C.
At 55N 15W (280 km further north) wind is 55 kt, temperature 0 C.

Wind has dropped here in west Mayo. V heavy rain though in the last while.

TomOnBoard

Very quiet in South Roscommon. ..

Kermit.de.frog

The weather in north Dublin right now reminds me of every single day I have ever spent in Galway.

Occasional strong winds touching gale force, spits and spots of rain, still 9.2c at the moment and we are only heading up from there overnight. The more persistent rain about to arrive.

squonk

The ME radar is showing an intense area of rain across Northern Ireland just now. It’s unusual to see such an organised and widespread area of heavy rain.

Discodog

squonk wrote: »

The ME radar is showing an intense area of rain across Northern Ireland just now. It’s unusual to see such an organised and widespread area of heavy rain.

And the circular pattern around Shannon - hope the radar isn't playing up.

Gaoth Laidir

Discodog wrote: »

And the circular pattern around Shannon - hope the radar isn't playing up.

That's called Bright Banding and is totally normal. It's caused by the reflection off melting snow at a certain level, and the rings show this effect at different scan angles. The radar is working fine.

squonk

Discodog wrote: »

And the circular pattern around Shannon - hope the radar isn't playing up.

Yeah I hope so. I thought the northern Irish reading looked a bit suspect. They’ll be flooded up there if the radar is correct.

mayo.mick

Deleted User wrote: »

Wind has dropped here in west Mayo. V heavy rain though in the last while.

25mm or so since midday here in east Mayo

Laurali

Icon has upgraded mayo for the main event in the early hours of tomorrow where gfs seems to have down graded.
Does icon notoriously over estimate?

Hooter23

Gaoth Laidir wrote: »

Ciara hasn't deepened in the 6 hours up to 12Z, still 969 hPa just east of New Foundland.
By 06Z tomorrow it will have deepened to only 950 hPa, so not rapidly intensifying, though it did start off as a low way down near Florida during the week.

Since its not deepening as rapidly as forecast maybe the track might change also and the storm may come closer to us

typhoony

Laurali wrote: »

Icon has upgraded mayo for the main event in the early hours of tomorrow where gfs seems to have down graded.
Does icon notoriously over estimate?

Yes gfs had a slight downgrade on winds for tomorrow morning, a mid range orange but nothing more unless this system bombs overnight which looks unlikely

Gaoth Laidir

Lovely hi-res MODIS image of the frigid air bubbling up into cumulus and then showers as it flows southeastwards off the sea ice in Baffin Bay, the source of Monday/Tuesday's cold air. Dewpoints in the area are below -25 C, so how much will the 3000+ km sea track modify this airmass by then? That's the question.

Gaoth Laidir

Hooter23 wrote: »

Since its not deepening as rapidly as forecast maybe the track might change also and the storm may come closer to us

It is deepening as forecast. It's just not "bombing" (as DublinLive would say). Forecasts have been remarkably accurate all week (up to now anyway).

YanSno

The speed it's traveling i would expect less modification. Compared to last week westerly

Rebelbrowser

Gaoth Laidir wrote: »

Lovely hi-res MODIS image of the frigid air bubbling up into cumulus and then showers as it flows southeastwards off the sea ice in Baffin Bay, the source of Monday/Tuesday's cold air. Dewpoints in the area are below -25 C, so how much will the 2000+ km sea track modify this airmass by then? That's the question.

From a quick look at the hi res models, only Euro 04 is seeing the snow a lot of us think possible....

SleetAndSnow

Big drops of rain in cork city of this evening. Not too windy yet, the occasional gust but not that strong either. Charts seem to be accurate enough so far.

Edit: gusts increased as I posted this

Gaoth Laidir

YanSno wrote: »

The speed it's traveling i would expect less modification. Compared to last week westerly

Yes, that's the only reason why I'm more optimistic about this particular northwesterly.

Oscar Bravo

Knock Shannon Cork and Dublin airport forecasting max gusts of 60 knots for a period tomorrow morning ,easing off a fair bit into the afternoon.

TheMilkyPirate

Gaoth Laidir wrote: »

Lovely hi-res MODIS image of the frigid air bubbling up into cumulus and then showers as it flows southeastwards off the sea ice in Baffin Bay, the source of Monday/Tuesday's cold air. Dewpoints in the area are below -25 C, so how much will the 3000+ km sea track modify this airmass by then? That's the question.

That image is class.

munsterlegend

Rebelbrowser wrote: »

From a quick look at the hi res models, only Euro 04 is seeing the snow a lot of us think possible....

Are they out to Monday night yet though?

pauldry

19.9mm of rain in Sligo since yesterday

12.1mm in past 2 hours alone but now 2mm an hour rate again about. Floods everywhere though

Discodog

Gaoth Laidir wrote: »

That's called Bright Banding and is totally normal. It's caused by the reflection off melting snow at a certain level, and the rings show this effect at different scan angles. The radar is working fine.

Thanks. I have often wondered as I have seen it before. I think the new radar image makes it more obvious.

pauldry

Storm Desmond in Dec 2015 is still my record rainfall event with 98mm over its course. 20mm from Ciara a long way off yet