Cold Spell Prospects and Discussion (January + Early Feb 2012)

kstand

Sponge Bob wrote: »

The fog is clearing around here thank God, I'll check the crows.

Check them immediately.

Redsunset

blackius wrote: »

@redsunset

Beyond day 10,that 32 day ensemble is like looking at tea leaves useless!

You go back over matt Hugo's twitter posts and see what he was saying about the ecm a month ago,a forthnight ago and you'll see that it's with all due respect to you nonsense to say it gets better if the 32 dayer says we'll have a block to the NW on feb 14th.
It may aswell say we will have widespread tornado's!

Point being and point often being forgotten in the ether here lately is that FI is still FI no matter who is tweeting it.
Beyond 10 days is virtually useless in my humble opinion right now even with the ECM,with model output being in such a state of flux.

Don't get carried away!
I'm sure Matt's brief twitter comments are more a statement of the eye candy rather than a belief that they could ever verify.

yes of course and I know this but I should think of new members that take it as gospel and make a health warning or perhaps not post it at all. Point taken

Duiske

GFS still refusing to play ball on this. Actually, at 168 its picked up the ball, given the crowd the finger and stomped off home. Going to an interesting weekend waiting to see which model has this correct.

Rebelbrowser

Yeah the 6z GFS has positively mild weather around 21 Jan as opposed to the Wild Bill Blizzard. Its v hard to reconcile such differences 8 days out.......(in fact differences start earlier than that)

WolfeIRE

The UKMO has drifted from its similar output to the ECM out to 144hrs which is not good news. The UKMO is indicating a less cold outlook for Wed into Thursday as it shifts the tilt of the jetstream from easterly to northeasterly. A sign that it may be siding with the GEFS output? We will find out in the next run or two.

200motels

WolfeIRE wrote: »

The UKMO has drifted from its similar output to the ECM out to 144hrs which is not good news. The UKMO is indicating a less cold outlook for Wed into Thursday as it shifts the tilt of the jetstream from easterly to northeasterly. A sign that it may be siding with the GEFS output? We will find out in the next run or two.

I think we could have missed the boat on this supposedly cold spell. I know the models are all over the place and it's hard to get a grip on things but I don't think we're going to get any major cold spell this winter.

Min

200motels wrote: »

I think we could have missed the boat on this supposedly cold spell. I know the models are all over the place and it's hard to get a grip on things but I don't think we're going to get any major cold spell this winter.

Well it is a boat that I hope is hijacked and kept away from Ireland.

WolfeIRE

Anyone watching the models will need to keep an eye on the HP ridge building up off Canada coast into Greenland on Thur/Fri of next week. It's positioning is critical to the extent of any cold. The further south or east it shifts, the closer we will be to what the GEFS is indicating i.e. cool not cold.

Just two more points, the medium range forecasting ability of either the ECM or GEFS will be in for some criticism over the next two weeks. The ECM has been consistently pointing since the weekend to some relatively severe cold for the UK and Ireland around the weekend of 21-22, while the GEFS has been consistently inconsistent since the weekend up to yesterday. The latter has now pointed to a more cool zonal setup.

While the ECM is being touted widely as the form model we could potentially end up with the ECM and GFS meeting half way leaving us in a setup not too dissimilar to the first three weeks of December when our weather was dominated by mild sw interrupted by brief but often wintry NW-northerlies. I do not not see it being as mild as the GEFS is making it out to be.

EDIT: Delw's UKMO update there would suggest that a middle ground of the ECM and GEFS is being considered by them.

delw

UK Outlook for Wednesday 18 Jan 2012 to Friday 27 Jan 2012:

Showers or longer spells of rain on Wednesday, with rain most persistent in northern and western parts of the UK, where strong, perhaps gale force winds are possible at times. Turning colder from the northwest through Thursday, with snow becoming increasingly likely across hills. Drier, brighter spells are most likely across the south and east of the UK. Conditions late next week and through the weekend remaining unsettled with a risk of wintry showers, especially in the north and over high ground, and also a risk of overnight frosts in quieter spells. The changeable conditions are expected to continue through into the last week of January with some spells of milder, wetter weather and also spells of brighter, colder and showery weather with frosty nights.
Updated: 1129 on Fri 13 Jan 2012

weatherfiend

All this is not good for the heart!! The frosty feel today is just great

pistolpetes11

delw wrote: »

UK Outlook for Wednesday 18 Jan 2012 to Friday 27 Jan 2012:

Showers or longer spells of rain on Wednesday, with rain most persistent in northern and western parts of the UK, where strong, perhaps gale force winds are possible at times. Turning colder from the northwest through Thursday, with snow becoming increasingly likely across hills. Drier, brighter spells are most likely across the south and east of the UK. Conditions late next week and through the weekend remaining unsettled with a risk of wintry showers, especially in the north and over high ground, and also a risk of overnight frosts in quieter spells. The changeable conditions are expected to continue through into the last week of January with some spells of milder, wetter weather and also spells of brighter, colder and showery weather with frosty nights.
Updated: 1129 on Fri 13 Jan 2012

Thats a real mash up of all possible scenarios !

Sponge Bob

Crow Report 13/01/2012

The local Crows here in Galway appear to have ceased their rutting activities from earlier this week and are now largely seen in particular trees and in pairs. However they appear to be inspecting a future nest location in the main and are not actually nesting....as in carrying and arranging twigs to and in a location centred on a particular tree.

I expect further developments (if any) by the middle of next week and will report then. No stormy events are showing up in any significant models that would unravel the Crows good work so I quite honestly expect to see twigs in place by then.

Naturally you are all welcome to inspect your own local rookery and report back here.

/Crow Report

talkabout

Can the crow reports please be moved to a more appropriate thread?

john mayo 10

talkabout wrote: »

Can the crow reports please be moved to a more appropriate thread?

+1

tzfrantic

john mayo 10 wrote: »

+1

+2

darkman2

ECM ensemble mean at 168hrs shows very good agreement for a cold Northwesterly and snow showers - turning very cold at night from next Wednesday aswell with widespread frost and icy patches. It's from Wednesday temperatures are really gonna struggle.


Further on the ensemble agreement is rock solid on the trough sinking South and bringing in either a Northeasterly or Easterly over the weekend. That means potential snow showers or longer periods of sleet and snow particularly in the East. But it's a while out yet. Like I say good agreement on the ECM ensembles. And no sign so far of a breakdown either with pressure rising to the North. If the ECM is right, typically as we have seen over recent years, we could be on the verge of a prolonged period of very cold weather. Could be.

only one

darkman2 wrote: »

ECM ensemble mean at 168hrs shows very good agreement for a cold Northwesterly and snow showers - turning very cold at night from next Wednesday aswell with widespread frost and icy patches. It's from Wednesday temperatures are really gonna struggle.


Further on the ensemble agreement is rock solid on the trough sinking South and bringing in either a Northeasterly or Easterly over the weekend. That means potential snow showers or longer periods of sleet and snow particularly in the East. But it's a while out yet. Like I say good agreement on the ECM ensembles. And no sign so far of a breakdown either with pressure rising to the North. If the ECM is right, typically as we have seen over recent years, we could be on the verge of a prolonged period of very cold weather. Could be.

I know it's a while out yet, but maybe snow or south east if it dd happen?

Sponge Bob

Not a very intense low
Where is the moisture coming out of. ????
Or is it likely to be frost instead???

Redsunset

only one wrote: »

I know it's a while out yet, but maybe snow or south east if it dd happen?

No North west, wind flows anti clock wise in northern hem low pressure On chart shown

pistolpetes11

talkabout wrote: »

Can the crow reports please be moved to a more appropriate thread?

There is a thread for it here :


http://www.boards.ie/vbulletin/showthread.php?p=75790476

blackius

only one wrote: »

I know it's a while out yet, but maybe snow or south east if it dd happen?

Initially an Ulster /North connaught,maybe north leinster event but as that low slides south the highs would link in the Atlantic and the tilt of the slider low would bring winds probably from the NE and East focusing the attention on louth,meath,Dublin,Wicklow and wexford for snow showers.
Not so sure of waterford as this is not a big low but unstable -9 850's or lower should they come would explode convection in the irish sea

Sponge Bob wrote: »

Not a very intense low
Where is the moisture coming out of. ????
Or is it likely to be frost instead???

The artic...and yes frost for sheltered areas,probably severe.

redsunset wrote: »

No North west, wind flows anti clock wise in northern hem low pressure On chart shown

Yes but when that low falls into the netherlands,they would be either north easterly or easterly.
The set up would mean that those NE/East winds could be there for a while.
The Northwesterly would be a temporary one whilst the low was moving down-day or two possibly max.

It's a week away so lets see what creeps into the reliable.

I am completely uncertain but it's nice to see something as interesting as the above creep as far as only 7 days out as it is.

It could be all gone before the timeline reaches the reliable.

#rollercoaster

tzfrantic

which is more reliable the ecm or the gfs the reason i ask it beacuse of the snow and cold the ecm keeps pointing to

Trotter

blackius wrote: »

Not so sure of waterford as this is not a big low but unstable -9 850's or lower should they come would explode convection in the irish sea

Its these streamers that in my experience anyway have provided the snow for Waterford. We get the cold, thats not an issue!, but any bad snow has come from an hour or two of heavy streamers that have appeared 2 or 3 times during 24/48hr cold spells.

The snow precip from the North is often blocked out by our 'Comeragh Mountain Shield', but I do remember in 2010 watching for the streamers to provide and oh they did!

Musicman2000

tzfrantic wrote: »

which is more reliable the ecm or the gfs the reason i ask it beacuse of the snow and cold the ecm keeps pointing to

Thats the problem, The ecm is normally the more reliable one, and the ukmo were backing the Ecm yesterday, But it backed off slightly this morning, and the gfs is really sticking to its own runs. Going to be a very tough one to call, Its really a sit on the fence situation.

blackius

tzfrantic wrote: »

which is more reliable the ecm or the gfs the reason i ask it because of the snow and cold the ecm keeps pointing to

Generally the ECM but they are all good usually within 48 to 96hrs which is the timeframe most users of weather forecasts are interested in.

It's hard to know what to think at the moment but this has happened before and gradually within the 96 hours to 120 hours ahead model outputs do usually somewhat converge.

As a starting point though,it's always usually cheery to see the ECM advocating the weather type you want but right now,the big GFS seems to be saying black to the ECM's white if you pardon the pun.

Model disagreement as stark as that means we just don't know yet other than hunches.

WolfeIRE

GEFS 12z rolling out now.

At 72hrs it looks to be edging slightly toward the ECM line of thinking.

Jetstream is angled more NNE than NE, while ridging is taking place closer to the coast of eastern canada than shown in the 6z run.

UPDATE

Looking very similar to ECM out to Wednesday afternoon.
Jet is making sure though that any cold is less aggressive as it nears Ireland than is seen on ECM. That said it does bring the cold further south on this run.

UPDATE

At 126hrs early Thursday - ridging to our west is collapsing allowing a quickly developing low pressure system over the atlantic (In ECM this LP system is forced up over Greenland). Looking like as you were for GEFS beyond this point. Some small developments in the first 120hrs or so since the 06z run though.

UPDATE

It's more or less as you were for the GFS with the exception of some ridging into Greenland around 240hrs or so.

UPDATE
UKMO 12z continuing to look similar to ECM, which is a positive sign for those looking for cold.

Cue next run of ECM - will it now back down on its cold outlook or will the Friday 13th standoff continue? The 12z ECM will start rolling out at 6pm IMT

tzfrantic

with the cold in the us does that have any effect on the jetstream and it's position

Harps

From what I can see the GFS develops an intense low south of Iceland on Monday night which doesn't appear on UKMO or ECMWF, another low over the US deepens as well which stops stops the ridge moving north towards Greenland. Can't see the jet on the other two but I assume its the main cause of the difference at the moment.

WolfeIRE

Harps wrote: »

From what I can see the GFS develops an intense low south of Iceland on Monday night which doesn't appear on UKMO or ECMWF, another low over the US deepens as well which stops stops the ridge moving north towards Greenland. Can't see the jet on the other two but I assume its the main cause of the difference at the moment.

Ultimately, it's the failure of the high to build off eastern canada into Greenland as happens on the ECM. This indeed does happen at around 240hrs in the gefs but that is way to far our to be read into in any great detail. The GFS pushes that low near Iceland much further south in this run alright which has the effect of dragging colder air further south over us on Thursday than was shown on the previous GFS run.

The fear now is that the ECM will lose its consistency and follow the GFS lead in downgrading any ridging toward Greenland next week. Or the ECM could stand its ground which would leave us in an unusual situation i.e. having the GEFS and ECM being very different 5 days out.

cherryghost

Just FYI I was looking at the last 2 winters and the threads and which run gave a better of indication of what actually came; ECM beat GFS 3-1. GFS however was far more accurate than the ECM at about 96hrs.