Atlantic Storms - 13th December 2011 Onwards Part 3

[Polar Bear]

Johnholmes you star thank you! A very happy pb.

[pyrotech]

Wow UKMO MOGREPS has the low moving further south than previous runs and so it looks less likely every run now, Watching GFS run now and gales are confined to France, Plus rainfall of any real intensity is South of UK now.

Would not get your hopes up folks, but it is a volatile setup and things can change very quickly.

[Matty M]

The plot thickens.

The latest High res NAE shows the potential of this system.

In the southwest approaches.

The charts i have posted are MAJOR.

And perhaps the UKM will make a coup here.

Much much different than any other SOL tonight.

Heads will be being scratched in Exeter!!

Edited December 13, 2011 by Matty M

[johnholmes]

The plot thickens.

The latest High res NAE shows the potential of this system.

In the southwest approaches.

The charts i have posted are MAJOR.

And perhaps the UKM will make a coup here.

Much much different than any other SOL tonight.

Heads will be being scratched in Exeter!!

Matt

You are looking at the first wave-the warm front wave NOT the main low which is still way back?

click on the European sector to show them both

Edited December 13, 2011 by johnholmes

[Matty M]

Matt

You are looking at the first wave-the warm front wave NOT the main low which is still way back?

click on the European sector to show them both

Ye i have! That is the centre of the storm system? a 976mb centre head towards Bristol?

[johnholmes]

Ye i have! That is the centre of the storm system? a 976mb centre head towards Bristol?

Matt please run the system through from T+12 to T+48 as far as NAE goes. You will see TWO centres one in the SW approaches at T+24 and one in a similar position at T+48

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=euro&MODELL=nae&MODELLTYP=1&BASE=-&VAR=pslv&HH=0&ZOOM=0&ARCHIV=0&WMO=&PERIOD=

Edited December 13, 2011 by johnholmes

[Matty M]

Matt please run the system through from T+12 to T+48 as far as NAE goes. You will see TWO centres one in the SW approaches at T+24 and one in a similar position at T+48

http://www.weatheron...V=0&WMO==

Yea i know. the centre that is moving through in the morning(tomorrow) in association with our complicated current low!

This low comes from out in the Atlantic and is what will spawn Thursday/ Friday storm. Hence why i posted the T42hrs and T48hr chart.

I don't understand your confusion?

I am just saying the prediction for T48hrs from the UKM NAE is very different to the T48hr GFS for example and previous global UKM and looks more dangerous for southern regions of England showing a deeper rapidly developing and more northerly tracking low.

NAE 48hrs

GFS 48hrs

Edited December 13, 2011 by Matty M

[johnholmes]

I agree with that Matty, depth only mind you, position is not much different. believe me its likely to change again before its finalised of that I'm sure.

your initial post showed only the first low that is why I commented, the link I've provided enables anyone to see what we are both discusiing.

no intention to cause upset I assure you.

Edited December 13, 2011 by johnholmes

[pyrotech]

Matt please run the system through from T+12 to T+48 as far as NAE goes. You will see TWO centres one in the SW approaches at T+24 and one in a similar position at T+48

http://www.weatheron...V=0&WMO==

Im not sure John That looks like the main Low at 18z Thursday approaching southwest much different to other models.

Run the whole sequence.

You sure as one at at T48 seems to come from right area and nothing signifigant left out in Atlantic

John would you give more credability at this range to NAE than GFS?

Edited December 13, 2011 by pyrotech

[johnholmes]

Im not sure John That looks like the main Low at 18z Thursday approaching southwest much different to other models.

Run the whole sequence.

You sure as one at at T48 seems to come from right area and nothing signifigant left out in Atlantic

John would you give more credability at this range to NAE than GFS?

usually but over the last 48 hours I think all of the models and UK Met perhaps more than the others has a ? over them. GFS has done quite well latterly-must have a look at the NOAA northern hem 500mb checks to see if that shows this up.

[pyrotech]

usually but over the last 48 hours I think all of the models and UK Met perhaps more than the others has a ? over them. GFS has done quite well latterly-must have a look at the NOAA northern hem 500mb checks to see if that shows this up.

Gfs used to have a tendency to find a trend in Fi and then drop it , then bring it back inline nearer the time. Not noticed it so much this year. Then it used to over cook systems but can not blame it for overcooking this one as all the models had similar intensity. Nae seems pretty reliable , in fairness to the other models thou, it does not go into fi (although think fi could be 24 hours at the moment)

[johnholmes]

Interesting looking at the NOAA checks for the 500mb charts for day 6, and the blip between GFS and UK Met shows up on it, both are back with ECM level pegging pretty well again.

[Liam J]

Well it's been another very stormy day up here, 74mph was the max gust recorded and the windchill has been incredible!

just starting to rain now, not expecting any snow down to this level tonight but the hills might catch a decent covering.

[Hurricane Debby]

OMG I just had a flash of lightning and a clash of thunder - so wasn't expecting that -where did that come from !

[Upgrade]

i saw that from here!

[Trugoy]

Any more updates from southeners on thunder storms tonight?? Saw some flashes in the east around brighton way at 8 which i think was from the isle of white so it went past my location over the sea!

Edit: Just as i post that another shower starts, won't get my hopes up though..

Edited December 14, 2011 by Trugoy the Dove

[Snow and storms]

Saw good flash and small rumble at about 11:30 sounded like it was just off the coast here. Wind picked up here, maybe gusting 30-35mph and rain becoming heavy. Off to bed for some well needed sleep after being kept up all night by last nights storm.

[Roger J Smith]

I posted in the model thread that the range of outcomes for Friday (Thursday night) is still quite uncertain and a significant storm for southern and parts of central England cannot be ruled out yet. But I think the chances are about one in three at best, the most likely track is probably south coast or Channel. That would tend to be mostly a rain and moderate wind outcome in southern England, with the main emphasis on drawing in colder air more rapidly.

The NAE probably represents the northern limit of where the developing storm could track, if everything fell into place. That would require a recurve of Wednesday's short wave maintaining an upper level WSW flow rather than an upper west to WNW into France.

With the time difference, I am likely to be watching developments continuously "all night" so if I see anything not covered in other posts or model solutions, I may be back in, if not, assume I have not seen anything to shake confidence in the model consensus solution.

[Robbie Garrett]

Cheif forecasters view - Recent computer model runs have tended to take the track further south but there remains a risk that the low pressure could track right across southern Britain, bringing potentialy damaging gusts of around 80mph. Associated with this risk would be heavy rain which could cause flooding issues. With snowfall to the west and north.

[West Sussex Kate]

Night all.....let's see what the models show in the morning!

[Robbie Garrett]

I may be wrong, but is that not Thursday Nights storm starting off in the North Atlantic? http://www.intellica...px?animate=true

Edited December 14, 2011 by Robbie Garrett

[ZONE 51]

Take a look at this feature for wednesday(today) evening just South of Ireland,

i would be maybe concerned about this,

this chart is the 500-1000hpa, see the cold air wrapped around this (potential storm) system,

next is the Isotachs (mph),

Then the Surface pressure,

charts are for time 1800hrs, lets take a look further ahead and see what develops,

at 2100hrs the surface pressure shows where the deep low is, this hitting the SW, potentialy damaging effects,

Its something to keep checking on, and thats before the unknown track of the thursday/friday storm,

so with the cold air wrapped around this system then maybe snowfall could develop,

at 0300hrs(into Thursday) this system is moving along the South coast,

look at the tight isobars in the Channel,

DATA - NAE -18z

Amazing sat image here(recent)

From the MetOffice - http://www.metoffice...test_uk_ir.html

Edited December 14, 2011 by ElectricSnowStorm

[Trugoy]

So when that ring of low pressure is directly over the south does it mean no wind but cold air and chances of snow??

[ZONE 51]

So when that ring of low pressure is directly over the south does it mean no wind but cold air and chances of snow??

Calm in the center

Take a look at NAE's modeling of the potential storm on Thursday, this track from west to east dragging down the cold air on its left side turning rain to snow,(see my arrows)

Thats why channel lows bring snow for the South, as snow falls on the North edge,

next is a chart of surface temperatures, look at the one above and see the warm sector, as shown here in the

SouthWest at 1800hrs

Edited December 14, 2011 by ElectricSnowStorm

[Aaron]

This of course depends on how cold it is in the South when the low sweeps through the Channel.. I wouldn't count on low level snow but the Chilterns could get a snow event.