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

Meteorite58

Very disturbed pattern of weather coming up from early Tues to Thurs . Early Tues seeing the first of the strong winds and Weds seeing a potentially strong wind event . Track , intensity and timing to be fine tuned over the next couple of days but a good time to keep a record on how this develops.

Can update the thread title when and if needs.







Early prediction from ICON of approx 45 hrs rainfall ( from early Tues morning to Weds night)

Meteorite58

A direct hit from ICON 12Z. Still a spread on track amongst the models which are still chopping and changing, ARPEGE keeps strongest winds up along the W coast, GFS strongest off the E coast , ECM out soon will be interesting. In general all showing very strong winds.

cobham

Tue 27th?

Meteorite58

Wind gusts and projected 6hr and 24 hr total precipitation.

Meteorite58

Rapidly intensifying Storm.

Meteorite58

ECM 12Z is now tracking the strongest winds over Ireland. Previous track was keeping the strongest winds off and along the W coast. This track and intensity is by no ways certain as yet. Very stormy on this run. Strong winds from early morning in the S and spreading up over the country , becoming stormy late afternoon early evening. This could change one way or the other. ECM and ICON very similar on latest runs.

Meteorite58

ECM 12Z 24 hr



Accumulated rainfall up to Thurs 03.00, most of which falling in about 42 hrs , more to follow on Thurs.

sdanseo

Latest ECM, if it panned out, justifies national red. Technically speaking.

What's a bit worrying is that we're 4 days out and ECM has recently fallen into line with other models and the trend getting more intense. This could be another Darwin.

Or, of course, it could be a hurricane force day in Iceland.

Sharp eye needed on this for the next 72hrs.

M.T. Cranium

Moon will be near perigee and northern maximum following yesterday's full moon, what that means is tidal ranges stay high longer than you might expect 4-5 days after a full moon. So any prolonged onshore winds will bring elevated coastal water levels.

(the northern max event is the most reliable storm correlative in my research model too, just tuck this factoid away, the next full moon almost simultaneous with the northern max as is always the case with late December full moons, so 21-23 December a possible stormy period, if the upper level pattern conducive to Ireland being in a storm track).

I actually checked in thinking this would be a good time to post a watch thread on the storm, so well done Meteorite the mind reader.

Harry Palmr

Get your trampolines in folks.

mickger844posts

A very interesting few days of model watching ahead. As always track will dictate who gets what but the odds are on some sort of event with the more extreme outcome most certainly on the table.

2013Lara

mickger844posts wrote: »

A very interesting few days of model watching ahead. As always track will dictate who gets what but the odds are on some sort of event with the more extreme outcome most certainly on the table.

Which part of the country is it looking most extreme? Obviously I know its subject to change!

M.T. Cranium

Different models show different regions so I don't think any of us are getting a strong signal about that, would say the situation is more likely to be orange level than either just yellow or up to red, but that's not carved in stone, and of course orange level conditions on the coast are not that unusual for them while if they got the same thing further inland, more of an impact on people and property.

There should start to be some model consensus by Sunday 12z or at the latest Monday 00z runs with this, I believe.

kenmc

Oh great. Flight on Wednesday morning could be fun, nevermind actually getting to the airport....

The origins for next week's events appear to be a low pressure system currently located between Florida & Bermuda. NHC discussion expects no tropical or subtropical development.

M.T. Cranium

So I just finished looking at seven different models and found seven different ideas of what's going to happen Wednesday and Thursday. ECM now has its strongest winds on Thursday. Arpege places a low right over Ireland. GFS still going with the one-two sequence of near miss events first north then south. GEM stuck on its late Wednesday windstorm. I know that's not seven, so ... your guess is as good as theirs. The subtropical low is definitely playing havoc with the models, and there appears to be another one about a week later near Bermuda too.

I don't even have a hunch to play on this, just waiting for some sort of dominant theme to emerge.

Meteorite58

All down to how the Subtropical low phases with the Low to the W on our Latitude around Tues. The models running through various scenarios with very different outcomes run to run atm. The ECM and others showing strong winds on Tues for a time but with variances, after that too wide a spread in outcomes, we will have to see.

After that for Weds atm the ECM keeping the strongest winds to the coasts and the bulk of the strongest winds missing us, similar to the GFS but huge uncertainty with this.

ICON showing very strong winds but mostly missing us on Weds

Latest ECM 0Z showing the lows doing a sort of pirouette on Thurs which brings further strong winds to our shores and no doubt rain also. Interesting set up, frustrating in it's uncertainty but intriguing to watch unfold.





Can compare these against later runs.

Meteorite58

Big uncertainty but can compare these charts with later runs.

Meteorite58

Looks like an active front going through quickly early Tues morning. The Hi Res models picking up what I think is a wave depression forming close to Ireland which could produce strong winds and very heavy rain. Need to keep an eye on this.












24 hrs rainfall approx

Meteorite58

Latest charts for Weds . High degree of uncertainty yet.

Will see what the ECMWF does as it rolls out after 18.00.

igCorcaigh

https://twitter.com/metoffice/status/1066740878126055425?s=19

blackwave

Rte weather were flagging that we are entering a very unsettled spell from Tuesday onwards.

Meteorite58

ECM showing strong winds on Tues and very heavy rain moving through quickly, flooding amounts in places, going by tonights run warnings coming into effect no doubt. At the moment gusting up to about 90 -100 km/h on coasts and gusting 80-90 km/h overland with a few gusts higher possible.

ECM Showing an area on the chart below which on this run anyway looks like getting 25 to 30 mm in around 6 hrs or so !

Meteorite58

HIRLAM similar rainfall predictions. Could be thundery also.

Meteorite58

IMO Going by the ECM 12Z Weds looking quite windy on coasts but not stormy on this run. More like gusting to 100 km/h or a bit more on exposed headlands and gusting 80 to 90 overland in general with a few higher gusts on higher ground perhaps. Going by this run which is similar to the last one and that kind of wind speed seems to be the general trend atm I think.









A lot of rain predicted t0 fall in a couple of days ( 40- 42 hrs )

M.T. Cranium

GEM seemed to have as good a handle on evolution as any, especially with the subtropical feature. Now RGEM shows this low steadily deepening to 955 mb by Tuesday 12z (at 43N 33W). It already looks well developed on satellite imagery east of Bermuda now.

As to how strong it can get by Wednesday, that may remain somewhat unresolved until tomorrow's model runs.

Looks like the strong second phase late Thursday is a real player too, showing up on various models now. That one takes more of a WNW to ESE track across Ireland so may be more impactful for Leinster than the earlier round late Wednesday which could be severe on west coast, parts of south coast and inland west.

As meteorite was saying, Tuesday could have its own excitement out ahead of what will now be Diana apparently (does that mean that storm name Deirdre is unavailable for use? -- think that's the protocol, with the Portuguese met service already naming the D storm "Diana" -- the aforementioned subtropical system -- as it impacts on their Azores territory).

Satellite imagery showing developing Diana south of weaker low near Nova Scotia, and the plains states blizzard forming over Missouri.

https://weather.gc.ca/data/satellite/goes_ecan_1070_100.jpg

(disclaimer -- image will change over time, 2015z Sunday image posted)

JanuarySnowstor

There's been a clear trend in the last 24 hours to weaken the system sufficiently to not cause any widespread disruption.
This could change back to something more severe though.
The rainfall is notable but not disruptive imo

mickger844posts

JanuarySnowstor wrote: »

There's been a clear trend in the last 24 hours to weaken the system sufficiently to not cause any widespread disruption.
This could change back to something more severe though.
The rainfall is notable but not disruptive imo

Severity of winds definitely less of a factor given today's runs but still plenty of rain and all told a dreadful Tuesday to Thursday period of weather ahead.
Still time for upgrades or downgrades yet as the Atlantic set up is very complex.

JanuarySnowstor

The 18z increases the gradient ever so slightly. Going on this run you would more than likely see a nationwide orange (just!).....maybe yellow and orange for coastal parts.
Typical winter fare really for late November

JanuarySnowstor

Thursday night has really ramped up.
It won't happen like that but if it were we would be looking at the top traffic light!!

jirafa

Joint Cyclone Center
‏ @JointCyclone


Atlantic #StormDiana Advisory Number 2
Max Wind Gusts: 70mph
Strength: WS
MSLP: 988mb
Diana a little stronger, expected to move across the eastward to east-northeastward over the western and central Atlantic...