Strong winds / Heavy Rain Tues 27 and Storm Diana Weds 28 Nov. 2018

M.T. Cranium

Storm Diana may be stronger than was generally thought, a ship report from 45.2 N 22.9 W at 18z says wind SSW 52 knots, pressure 954 mb.

10m wave height, temp 17 dp 14.

I searched back and this ship was not reporting at earlier hours back to 12z.

Satellite imagery shows centre is close to 45N 25W.

There are two ocean buoys (Pap, K1) in the path of the cyclone for later updates.

Surprised a ship was routed to that position unless it's there deliberately to measure the storm.

This might imply a robust orange alert justified for south coast 0600h-1200h.

spookwoman

update

Marine Warning
Status Orange - Gale Warning
1. Southeast to south winds will reach gale force 8 at times tonight and overnight on all Irish Coastal waters and on the Irish Sea.
2. Southerly winds veering southwesterly will reach gale force 8 or strong gale force 9 during Wednesday on all Irish Coastal Waters and on the Irish Sea, with storm force 10 winds for a time from Mizen Head to Valentia to Loop Head.

Issued: Tuesday 27 November 2018 19:00

M.T. Cranium

That ship report is far enough from the centre to justify an estimated central pressure of 948-950 mb at 18z.

A more exact centre fix would be 45.5N 25.5W. That is about 150 nm west of the ship's position.

Satellite image suggested the ship was in the "outer eyewall" feature that the storm has (a rough analogy, not saying it has tropical characteristics). Wind streaks can be seen arriving at that position from the WSW and it appears to be an area of convection.

With the very fast forward speed of Diana I think south coast could see gusts as high as 67 knots. The usual ratio of about 1.4:1 for gusts suggests current conditions are at least 50G70. The land approach may intensify the mixing down while the storm weakens slightly, so steady state until it passes the south coast would be my hunch, and it could be most severe in the southeast rather than the southwest this time, although anywhere from Sherkin Island east may see those gusts. Peak gusts further north may be more restrained, 50 to 55 knot range possibly.

As mentioned by several posters, the south to southwest wind direction will have a different impact around Dublin than today's windstorm, and generally less severe but possibly more blustery well inland as winds move up to the west of the higher terrain.

spookwoman

MT ship about here?

Storm 10

There are quite a lot of ships out in the storm area

M.T. Cranium

Yes that looks right. Unless it's a naval ship sent out to get a reading, I was very surprised to see it there, ships nowadays are routed well away from that kind of setup and I could not find any sign of it at 15z or 12z (most report on the 3h intervals). So I am not sure which way it's heading (let's hope not down).

spookwoman

M.T. Cranium wrote: »

Yes that looks right. Unless it's a naval ship sent out to get a reading, I was very surprised to see it there, ships nowadays are routed well away from that kind of setup and I could not find any sign of it at 15z or 12z (most report on the 3h intervals). So I am not sure which way it's heading (let's hope not down).

busy out there
https://www.marinetraffic.com/en/ais/home/centerx:-25.0/centery:45.7/zoom:5

JanuarySnowstor

I'm enclined to agree MT the south coast from Kerry through Cork and On to Waterford could see disruption from this. Then again I guess that's what an orange level alert states anyway.

Meteorite58

At this late stage still some difference amongst the models, GFS, ARPEGE and ICON would reflect Met Eireanns forecast to some extent. Hi Res models HIRLAM and AROME look a bit underwhelming at this stage.

ECM in my estimation probably the most reliable and consistent Model is reflecting and matching the warnings the most at this stage. The model is slow to roll out tonight. So far probably up ever so marginally in wind speed on Southern coasts than the last run.

Keeping an eye on the SE, looks like a very tight gradient, 850 hPa winds very strong.




Note 850 hPa Winds




The high wind speed in bold white is a mountaintop

Mount Vesuvius

Recent top wind gust, this will come down a lot when it comes near Ireland.

Meteorite58

Big seas tomorrow and over the next couple of days.

Gaoth Laidir

M.T. Cranium wrote: »

Storm Diana may be stronger than was generally thought, a ship report from 45.2 N 22.9 W at 18z says wind SSW 52 knots, pressure 954 mb.

10m wave height, temp 17 dp 14.

I searched back and this ship was not reporting at earlier hours back to 12z.

Satellite imagery shows centre is close to 45N 25W.

There are two ocean buoys (Pap, K1) in the path of the cyclone for later updates.

Surprised a ship was routed to that position unless it's there deliberately to measure the storm.

This might imply a robust orange alert justified for south coast 0600h-1200h.

That ship is this one, Diamantgracht (PBLQ). The anemometer is probably tens of metres above the surface, so the wind might be a little overdone. It strangely doesn't give a heading and speed in the SHIP report, but its last report on the 22nd was 48.7N 68.2W, so it's most likely heading towards Europe and getting out of the storm's way.

sparrowcar

Or maybe one of the wind turbine fans on the deck picked up the wind speed?


first party benefits

M.T. Cranium

I had a PM about possible tornado damage to sheds on a farm in Kilkenny. Will see if that poster would share on here, or give me permission to share the PM. Going to look for a radar depiction at the stated time to save for later. I asked if any visual evidence it was a tornado and not just a very strong gust. Arome may have verified in that one spot after all. (earlier I was questioning the 140 km/hr wind streaks it was showing).

As to this incoming storm, watching the PAP and K1 buoys now, steady 30 knot southerly winds there and slowly falling barometers. The PAP buoy is at 16.5 W, the K1 at 13, and both about 49N. That ship may grace us with another report. I was looking at all the ships out there on the map supplied, unfortunately none of those near Diana have joined in with a wind report on the site I use anyway. I suspect they are mostly fishing vessels, the larger ocean container ships would be routed well away from winds and waves like that as they don't want their gadgets ending up on the seabed.

The track reminds me a bit of a noteworthy past storm, 27 Feb 1903, one that produced severe gusts in the southeast and rivalled Darwin for trees blown down. Not saying we have this to face but a slight chance we might need to go red from orange on this (maybe 1 in 20 chances).

Should know by 0300h with the network of buoys, all depends on how long Diana maintains a distinct centre and what its actual pressure is, seems to me it was 5-10 mb lower than thought from that ship report at 18z. Current centre fix from satellite is 46.1N 24.8W. The cloud feature where the ship report was made has raced to 47N 20W (a displacement of 2 deg north and 3 deg east roughly in 3 hours). Forward speed of the system is around 50-60 knots (which is why I am watching this very closely). It is not exactly swerving north with any enthusiasm yet either and its associated jet stream was staying somewhat separated from the subarctic jet so I have to wonder if last minute corrections lie ahead.

It's seems to be getting very windy here in Cork now.. Is this too early to be storm related?

M.T. Cranium

Well that is 52 knots at a bit of elevation but as ship reports go it is a strong one and the pressure if accurate was low compared to map analysis (maybe not that much). Perhaps I am also subconsciously thinking if the out-front wavelet can do what today's "overnight sensation" managed to do, the acorn and tree might apply here. That sector of the North Atlantic primed for development, PAP and K1 buoys seldom go much past 40 knots so let's see how they respond in a few hours.

M.T. Cranium

Deleted User wrote: »

It's seems to be getting very windy here in Cork now.. Is this too early to be storm related?

It is related as there is a leading wave with a bit of energy passing to west of Kerry now. Expect a gradual increase in wind speeds peaking at around 0700h to 0900h in Cork. I will say 58 knots at the airport and 65 at Roches' Point peak gusts, 5% chance of 70 and 80 at those locations.

About the same for Waterford towards late morning.

Gaoth Laidir

M.T. Cranium wrote: »

Well that is 52 knots at a bit of elevation but as ship reports go it is a strong one and the pressure if accurate was low compared to map analysis (maybe not that much). Perhaps I am also subconsciously thinking if the out-front wavelet can do what today's "overnight sensation" managed to do, the acorn and tree might apply here. That sector of the North Atlantic primed for development, PAP and K1 buoys seldom go much past 40 knots so let's see how they respond in a few hours.

That pressure report of 954 hPa doesn't seem to fit in with the Meteocentre analysis for the time, albeit automated. The 976 isobar coincides with the ship's position.

igCorcaigh

Met radar on the blink, but rain started here in Cork city.

No winds as I can feel here.

Will this be a more localised gusty event? They can be more damaging in my experience.

Gaoth Laidir

18Z UKMO analysis. They don't seem to have taken that report into account.

sdanseo

Gaoth Laidir wrote: »

18Z UKMO analysis. They don't seem to have taken that report into account.

Same time. The information at 18Z from the ship might not have made it into the 18Z FAX?

Meteorite58

Quite windy here near Tralee, 10 min avg 40 km/h now for over an hour , gusting ove 60 km/h SE




https://twitter.com/BallybunionBuoy/status/1067538763121926145

Gaoth Laidir

sdanseo wrote: »

Same time. The information at 18Z from the ship might not have made it into the 18Z FAX?

I would say that's unlikely. The analysis has human input so Ship reports would have been considered and these come in a few minutes past the hour.

Meteorite58

Rainfall Predictions , the SW and W look to get the heaviest amounts .

Oscar Bravo

2202 Met Update

Very windy on Wednesday with severe and potentially damaging gusts associated with Storm Diana. The south to southeast winds will be strongest across the southern half of the country during the morning but the strong winds will extend nationwide during the course of the day and veer southwest in direction. Showery rain will accompany the strong winds with some locally heavy downpours. Top temperatures of 12 to 15 degrees.

irishrover99

Oscar Bravo wrote: »

2202 Met Update

Very windy on Wednesday with severe and potentially damaging gusts associated with Storm Diana. The south to southeast winds will be strongest across the southern half of the country during the morning but the strong winds will extend nationwide during the course of the day and veer southwest in direction. Showery rain will accompany the strong winds with some locally heavy downpours. Top temperatures of 12 to 15 degrees.

Well at least it’s going to be mild 😀

igCorcaigh

Fairly heavy rainfall now.
Even today, when it was dry, the river looked brown and turbulent.

High tide at rush hour, when the highest winds will hit.

M.T. Cranium

In fact the ship report is right on the map, see it there? And it says 542 for pressure which is code for 954.2 mbs. So they ignored it in the analysis.

Wouldn't be the first time a ship barometer was off by 22 mbs, but it would have to be quite a tall ship to be an unconverted reading.

We may find out when Diana visits the buoys. (so to speak)

Meteorite58

Max Gusts being predicted by the models

marvsins

Flights cancelled at Cork airport up to midday tomorrow.