Eleanor more firey than the GFS anticipated

[xmetman]

Eleanor more firey than the GFS anticipated

(ignore the contouring)

[xmetman]

Just after I published this blog the Met Office DID issue an amber warning. 

Here's the Chief Forecaster's assessment:

"Storm Eleanor continues to develop and will move eastwards during Tuesday evening and <strong>there is now increased confidence</strong> of a spell of very strong winds affecting southern counties of Northern Ireland, which will then move eastwards across parts of southern Scotland and northern England overnight before clearing into the North Sea early on Wednesday morning. Gusts of 70 mph are likely quite widely, and 80-90 mph gusts are possible along exposed Irish Sea coasts."

I just love the wording "there is now increased confidence" - what they really mean to say (but can't), is that Eleanor is much deeper than the NWP model forecast, and the wind is meaning 52 knots and gusting 76 knots at Mace Head!

[xmetman]

[Freddie]

On Tuesday, 2 January 2018 18:39:49 UTC, xmetman wrote:

Just after I published this blog the Met Office DID issue an amber warning.

I just love the wording "there is now increased confidence" - what they really mean to say (but can't), is that Eleanor is much deeper than the NWP model forecast, and the wind is meaning 52 knots and gusting 76 knots at Mace Head!

That's a bit harsh.  I'm sure they were fully aware of the potential for the storm to develop as much as it is - but the situation was finely balanced vis-a-vis the position of the low under the jet, as far as I can tell.  A few tens of miles either side and it would be in a less favourable position and consequently wouldn't develop as much.  Therefore it looks as if they were waiting to see the whites of its eyes before pushing out the amber warning.  I guess they are aware of accusations of "over warning" that fly around from time to time, so bided their timebefore upping the warning classification.

--
Freddie
Fishpool Farm
Hyssington
Powys
296m AMSL
http://www.fishpoolfarmweather.co.uk/
https://twitter.com/FishpoolFarmWx for hourly reports

[xmetman]

I suppose I am being a bit harsh, but if they were indeed "fully aware of the potential" why didn't they just issue an amber warning with the yellow one they issued at 11 UTC this morning?

[Brian Wakem]

Given the position of the tick in the original warning matrix, didn't they have to upgrade it to amber?  As it is actually happening it must be 'Very likely' and therefore cannot stay yellow.

What I don't understand is why they marked it nearer unlikely than very likely in the first place.

[Freddie]

Because potential is just that - it may happen. They didn't go amber until they thought "it will happen". That confidence wasn't justified until development was underway. I think the ground truth of the Irish observations may have just been coincidence.

--
Freddie

[Richard Dixon]

Knock 29 mph gusting 96 mph? Echoes of Gatwick's 34 mph gusting 99 mph (IIRC) in the October Storm...Knock was just S of the cloud hook with some interesting signatures in the imagery that I'm sure Smartie will probably look into in due course....

Richard

[Freddie]

Yes, definite sting jet signature.
--
Freddie

[Richard Dixon]

On Tuesday, 2 January 2018 20:39:05 UTC, Freddie wrote:

Yes, definite sting jet signature

I never say definite until someone's re-run a model and done some cross-sections !! 

Richard

[Freddie]

Wise, but I see the signs in the imagery.

--
Freddie

[Smartie]

The Knock airport gust was from N of W so prob CJ esp if close to cloud hook flank. Can't raise the plot for Ballyhaise but last report is 32/104 kph from west RH 87% so CJ as well at this time.

Mace Head still gusting 96 kph and radar littered with showers so not over yet for southern central Ireland.

[Smartie]

Sting jet almost certainly present from satellite and radar imagery presentation. 

The Mace Head 17Z report was from 139 kph from WSW accompanied by a drop in RH so is a suspect SJ gust.

SJ gusts will be from the SW or WSW and relatively low RH, veering gusts from the W to NW are likely due to the CJ and relatively high RH.

[xmetman]

[xmetman]

We'll have to disagree about this one!

I always thought the point of any warning was that it was proactive and made in good time to do something about rather than reactive when something had already happened.

[xmetman]

A bit slapdash but it's about right. Eleanor still has a long way to run and could cause more problems before she exits stage right. 

[Freddie]

I agree. That's why they put the yellow warning out to raise awareness - nicely helped by Met Eirann naming the storm. But because of the uncertainty surrounding the location and rate of deepening (because of the inherent sensitivity of the low position in relation to the jet exit - made worse by the strength of the jet and the speed of the short wave trough driving the position of the jet exit) then they couldn't call amber until they were absolutely certain that the engagement was occurring at a time and location where significant impacts would occur. Looking at NWP ensembles, many solutions were predicting the rapid deepening to occur later. If there had been more agreement in the latest runs then I'm sure they would've called it sooner. What you're asking is for it to be called as soon as it was a possibility - which over a period of time would result in a lot of false positives, which would damage confidence in the warnings.

If you look at the impact matrix then you can see that they had their hands tied regarding beefing up the warning until confidence was great enough.

--
Freddie

[Freddie]

Oh, and it wasn't reactive as the impacts hadn't affected the warning area yet. I thought thus one was a well-timed call - and I'm happy to admit that that isn't always the case.

--
Freddie

[Brian Wakem]

The warning just issued is complete gibberish to me.  They've moved the tick down to 2nd from bottom in terms of likelihood, yet it actually states in the text that 65mph gust are "likely" and in fact were happening when the warning was issued, therefore the tick must be placed in the top row.  If the impacts are expected to be low and therefore they only want a yellow instead of amber warning then they should move it left.  I don't think the metoffice understand their own warning system.

[Brian Wakem]

I see now they actually have moved the tick to exactly where I suggested, top row, second from left.  Maybe they read this group! 

[xmetman]

They would be mad not to...