Possible severe Atlantic storm Wednesday 18th December 2013 onwards

[Coast]

For my patch, based on the output posted by Coast earlier, the main event is from something like 6pm to 8pm, but still a case of watch this space! I imagine.

Slight downgrade on the wind speeds from the 12z GFS still very strong though mean speeds between 50 to 65mph across the West coasts of Ireland and Scotland. The GFS has overall made the low slightly not as deep as the previous runs.

 

Looks like it kicks off in the SW late afternoon, but GFS is showing more activity further to the North than the previous gusts down along the South coast:

 

 

 

These charts caught my eye for Wales, the SW and then SE:

 

 

 

 

 

 

Clearly even at this stage 'the devil is still in the detail' (taken from the NW standard stock of useful phrases to use when the weather wants to bite us in the posterior) and although this first period of heavy rain and wind looks like bringing many areas gusts up to 60 mph (70mph in Scotland) I think there could be one or two localised 'events' going on.

 

Shear is down a little on the last few days, but could still whip up some helical stuff: 

 

 

 

Friday now coming in to view on GFS lightning wizard:

 

Edited December 17, 2013 by Coast

[Matty M]

Still great uncertainty with regard to this storm.

 

NAE & GME would throw some violent winds into parts of NI & Scotland while the GFS leaves the guts of the 

storm winds out to the northwest.

 

Who would be a Forecaster!

[Coast]

Who would be a Forecaster!

 

 

[BurntFishTrousers]

Still great uncertainty with regard to this storm.

 

NAE & GME would throw some violent winds into parts of NI & Scotland while the GFS leaves the guts of the 

storm winds out to the northwest.

 

Who would be a Forecaster!

Yes, I'm not still convinced with 24 hrs to go if this will be an Outer Hebrides event only or a much larger swathe.

[Matty M]

Maybe NAVGEM is gonna pull a model WIN out of the fire

 

Edited December 17, 2013 by Matty M

[Coast]

The rain element of tomorrow night from GFS:

 

[johnholmes]

I can't believe that no warnings have been issued covering London & SE yet when most of the MetO and NetWeather forecasts predict gusts of 50-60mph tomorrow evening and a more prolonged spell of 50mph+ gusts through Friday night and the majority of Saturday! 

 

patience rather than impatience for tomorrow=looks about 50mph on current ideas. As to Saturday you will be highly unlikely to ever get a warning from Exeter this far out. Wanting specifics thus far out is totally impractical regardless of what any model may suggest.

[johnholmes]

That's rather like what happened with St' Jude the really intense spell of winds only lasted about half an hour as the sting jet effect took over and the low pressure swung out into the north-sea yet they gave warnings about that storm days and days in advance, makes you wonder now whether they where that worthwhile, saying that people where caught out by it and killed as trees came down so in hindsight I guess the warnings where rightly issued, just seems strange how the MetO and the media seem a lot less concerned with this storm despite the predicted winds being arguably stronger!

 

bit of a difference in the expected track is there not? the one this week is way further NW than the St Jude one?

[Matty M]

UKM differs quite substantially ( in terms of Land impact winds)  to the GFS at 30hrs

 

Edited December 17, 2013 by Matty M

[Coast]

SKYWARN UK SEVERE WEATHER WARNING #044

ISSUED: 1100UTC TUESDAY 17TH DECEMBER 2013

 

SKYWARN UK HAS ISSUED A WARNING FOR SEVERE WEATHER AS FOLLOWS:

 

STRONG, POTENTIALLY DAMAGING WINDS - WESTERN ISLES, WESTERN AND NORTHERN SCOTLAND, NORTHERN ISLES

 

IN EFFECT UNTIL 0600UTC WEDNESDAY 18TH DECEMBER 2013

 

DEEP ICLEANDIC LOW GENERATING SEVERE GALES ALONG THE OCCLUDED FRONTAL ZONE

 

DISCUSSION:

 

THERE IS STRONG MODEL AND PARTNER AGENCY CONFIDENCE IN THE LIKELIHOOD OF A SEVERE WEATHER RISK DURING LATE TUESDAY AND OVERNIGHT. A STRENGTHENING ATLANTIC JETSTREAM DEVELOPS A SUB-950MB LOW INTO ICELAND DURING THE DAY, GENERATING A BROAD FRONTAL ZONE WHICH INCREASES SURFACE WINDS TO POSSIBLY ABOVE 50MPH TRANSITING THE NORTH OF THE UK. GUSTS ABOVE 80MPH ARE LIKELY, WHICH MAY CAUSE DISRUPTION TO INFRASTRUCTURE AND POSSIBLE DAMAGE TO PROPERTY. LARGE SWELLS ARE TO BE EXPECTED ALONG COASTAL AREAS, POSSIBLY LEADING TO SOME FLOODING. THIS WARNING MAY BE UPDATED. PLEASE MONITOR WEATHER AND TRAVEL INFO AS NECESSARY. THIS ALERT WILL BE SUCCEEDED BY FURTHER DETAIL FOR THE COMING 48HRS, PLEASE CHECK BACK REGULARLY FOR UPDATES.

 

 

http://www.skywarn.org.uk/

[laserguy]

Scotland,Scotland,Scotland.... it's always bloody Scotland. Me? I'm fully prepared for 'mainly dry with sunny spells' with maybe the odd sprinkle thrown in.

[The PIT]

Tomorrow won't really effect us although we'll probably notice the switch to westerly winds. Friday being upgraded again which we should notice.due to the direction.

Edited December 17, 2013 by The PIT

[Matty M]

Ummm more models diverging from the GFS this evening.

 

[gottolovethisweather]

Just because something is short lived doesn't mean it isn't worth issuing warnings for,

 

Fair enough but we don't make the rules and have the responsibility to do so. What I would do from personal level is inform your own relatives and friends etc. of the potential.

[The PIT]

I can't believe that no warnings have been issued covering London & SE yet when most of the MetO and NetWeather forecasts predict gusts of 50-60mph tomorrow evening and a more prolonged spell of 50mph+ gusts through Friday night and the majority of Saturday! 

Oh but there is http://www.metoffice.gov.uk/public/weather/warnings/#?tab=warnings&map=Warnings&zoom=5&lon=-3.50&lat=55.50&fcTime=1387324800&regionName=se issued at 11:37.

Perhaps you didn't look before posting...... Oops or the bloke who does updating forgot to click upload.

[Eskimo]

Oh but there is http://www.metoffice.gov.uk/public/weather/warnings/#?tab=warnings&map=Warnings&zoom=5&lon=-3.50&lat=55.50&fcTime=1387324800&regionName=se issued at 11:37.

Perhaps you didn't look before posting...... Oops or the bloke who does updating forgot to click upload.

That's why I hate the MetOffice warnings, London is not even in the warning zone. It's misleading!

[Sainsbo]

So much inconsistency between the models despite being only around 36 hours away.

 

12z GEM agrees with the GFS, and wants to take it further north than the others, and the UKMO has it a little further south. ECM is somewhere inbetween.

 

JMA and NAVGEM have it considerably further south than the others.

 

Whichever end up to be correct, it looks like it could be very windy for the north on Thursday. As with most Low pressure systems, it seems the best way to do it will be to nowcast when the time comes!

 

http://earth.nullschool.net

 

Been posted a few times already but it looks like it might come in handy over the next few days to see what model has gotten the track right, if there are still inconsistencies by then.

Edited December 17, 2013 by Sainsbo

[Matty M]

ECMWF deeply concerning for parts of northwestern Ireland.

 

[knightrider]

Oh but there is http://www.metoffice.gov.uk/public/weather/warnings/#?tab=warnings&map=Warnings&zoom=5&lon=-3.50&lat=55.50&fcTime=1387324800&regionName=se issued at 11:37.

Perhaps you didn't look before posting...... Oops or the bloke who does updating forgot to click upload.

But that warning doesn't get any further east then Hampshire, what about SE and the Home Counties?

[The PIT]

That's why I hate the MetOffice warnings, London is not even in the warning zone. It's misleading!

Well when I noticed it I thought how come not the rest of the country as the same winds are shown moving west to east.

In the next few days I wouldn't be surprised if many places exceeded 50mph at times.

[knightrider]

Well when I noticed it I thought how come not the rest of the country as the same winds are shown moving west to east.

In the next few days I wouldn't be surprised if many places exceeded 50mph at times.

Yep I can easily see that, and something to note is that Friday's storm looks bigger in terms of it's mass, tomorrow's low pressure has quite a small vortex around the centre whereas the centre of the weekend's low is huge which will probably mean it'll remain on the windy side throughout the weekend.

[Matty M]

Here comes the Armegeddon storm, this time a little later on Christmas Day.

 

[The PIT]

Here comes the Armegeddon storm, this time a little later on Christmas Day.

 

Heres' your xmas present. A new roof but first santa needs to remove the old one first.

[Liam J]

Here comes the Armegeddon storm, this time a little later on Christmas Day.

 

 Yikes!! The Christmas period really is gearing up to be stormy, one to remember for the wrong reasons?! Anyway next week is a long way off yet...

[Zenarcher]

The models this evening are still unsure on the exact track of this system even at less than 30 hours away. Some have it slightly more North or South.

 

Onto the ECM at 30 hours it shows a 956mb low to the North West of Ireland,

 

 

Here's the wind chart showing very high speeds,

 

 

At 36 hours the low drops to 952mb and strong winds hit Western Scotland,

 

 

And the wind chart showing mean speeds over 57mph pass through the coastal parts,

 

 

Onto the high res model NMM,

 

This evening and tonight will be windy across North Western parts of the UK currently gusts over 50mph are being recorded,

 

 

These winds will ease off around 3am tonight. Now onto Wednesday 8pm just at the low arrives all of England and Wales will have widespread gusts of 45 to 65mph.

 

 

1am Thursday gusts over 75mph across Western Scotland,

 

 

Looking at the ECM and GFS data they both seem confident in themselves about the low position even though the actual two show something different. If the GFS and NMM are correct then Ireland would still see high gusts but not as extreme to what the ECM shows.