Winter/Spring 2013 (Model Output Discussion)

derekon

Redsunset wrote: »

I have put 0-120hrs only in thread title.

While the Fantasy Island time period is debatable in certain synoptic episodes. Now being a good example. I feel it helps to differentiate between the two threads.

So 120hrs or 5 days is plenty to talk about. Bar picking out trends, the rest is pie in the sky for details.

Excellent idea Redsunset and this parameter should allow some semblance of reality to return to this thread.

Roll on the 5 days model watching - and hopefully we will get some beefy snow / cold charts within the "reliable timeframe" of 5 days. Don't forget folks, its only day 9 of the Irish winter so we have around 80 days to go with hopefully lots of fun in store......:D

D

Elmer Blooker

The possibility of an undercut? very unlikely but not impossible with FI around +96 imo. Shame pressure isn't higher to the north.
The weather for the week ahead should be interesting (after 1.35 news on RTE1) Will ME go for "uncertain" later in the week or have the Atlantic barging in?

BLIZZARD7

Nice to see short term upgrades on the models this morning, the atlantic dosent look like breaking through properly on any runs today, it does get as far as Ireland and then the low pressures just stop dead and start to get stronger while still stalling.The track of these lows is key, are we going to get immense amounts of rain? Or will we see immense snow totals? Very interesting output at the moment and the short term improvements could mean we are back in cold easterlys faster than expected, BUT it also means FI is at +72hrs now.

Slider lows is the new theme today I think.





Dan

nacho libre

snaps wrote: »

seems even the cold now is dissapearing next week. looks like we will be in a southerly wind direction form as early as monday. Today has been a gorgeous day. shame.

my feeling is that it could be a case of short term pain from the perspective of irish snow addicts. the atlantic is going to win over ireland on Thursday , but cold air may possibly hang on in the north east of England, resulting in a north- south cold divide over here.
for us, i think the key is if the polar vortex displacement to Siberia encourages height rises to our north west, in about 11-12 days time, which, as we all know, is our best chance of getting sustained cold. we then could be in for a interesting Christmas period;)

Elmer Blooker

Happy enough with that forecast from Gerry Murphy a few minutes ago.
Friday's chart looked very interesting with LP just to the south so a brief battleground is not out of the question, an undercut or slider low is still a possibility as I said earlier.
Also no mention of the dreaded four letter word - mild. Gerry M said next weekend will be "a little less cold" I'm a lot more optimistic than I was yesterday.

Redsunset

https://www.youtube.com/watch?v=E3muqOcsojc

snaps

Looking at latest 12zs both gfs and ecm, looks like that nasty low pressure in the atlantic will hang around like a party pooper for around 5 days. Could be very very wet and windy for the duration. Our back garden is a swamp at the moment.

Mr Cumulonimbus

Looking at the current 18Z GFS out to +120 there seems to be a downgrade on any wind event as we move into next weekend.

It doesn't appear to be as aggressive as the 12Z ECM in bringing in the Low pressure from the central Atlantic, apart from what appears to be a smaller secondary feature.

Weathering

Yeah, the wind event was really not going to happen IMO.
With all the confusion in the models it was highly unlikely to nail down such a powerful "possible event" so far away.
Uncertainty is the flavour of the models this weather more than ever
Pardon the pun

maquiladora

Still a lot of uncertainty with that potential wind/rain event.

18Z GFS is only one run of one model.

Look at the latest Met Office chart for 120 hours.

Elmer Blooker

maquiladora wrote: »

Still a lot of uncertainty with that potential wind/rain event.

18Z GFS is only one run of one model.

Look at the latest Met Office chart for 120 hours.

Not a bad chart, nice to see the jet stream so far south.

Elmer Blooker

Wait a minute. how the hell can you get from this chart to the chart that maquilladora posted in just 24 hours? its not making sense to me anyway.

maquiladora

Elmer Blooker wrote: »

Wait a minute. how the hell can you get from this chart to the chart that maquilladora posted in just 24 hours? its not making sense to me anyway.

It's a rapidly developing low. You can see it south of the main Atlantic low at 96 hours.

Harps

I still don't quite know the mechanics behind how these systems form but there's a wave just west of the Azores which I'd assume interacts with the jet stream and intensifies as it swings north

pistolpetes11

Harps wrote: »

I still don't quite know the mechanics behind how these systems form but there's a wave just west of the Azores which I'd assume interacts with the jet stream and intensifies as it swings north

I thought that was the shortwave that could potentially cause the undercut ?

Redsunset

Ok without going into a mini ramp, I think Met Éireann are right to mention rain, sleet and possible snow.

Just looked at latest 0z Ecm 50 members ensembles and there is some showing enough undercut to bring about a good wintry mix. Elevation will still be key though but if the low does indeed track slowly south then don't be surprised to see sleet/snow at lower levels for a time in heavier bursts aided by evaporate cooling. Sea levels are basically all rain.
150-200 metres and above could see big wet snow with temporary covering.

Now this is all speculation of the low playing ball.
Milder air could arrive quicker and further north and so this would then be a bust.

Straw clutch really of a breakdown.

Nabber

Looks like the PV is in control again

Rebelbrowser

Redsunset wrote: »

...
Straw clutch really of a breakdown.

The problem is that even use of the word breakdown presupposes there was, ultimately, a particularly cold spell to breakdown...

All v disappointing for snowlovers like me but I suppose its the chase (and frequent disappointments along the way) that makes it all the more interesting when, every now and again, it comes off...

leahyl

I'm disheartened but not as much as I would have been a few years back - this forum has taught me to be prepared for downgrades!:D

snaps

Where's all this rubbish in the Irish papers coming from today about Siberian weather coming from Wednesday? Thought this was when it was going to change milder?

Redsunset

Model/Technical Discussion Please.

whitebriar

BBC forecast,just now by Darren Brett had full confidence of the Atlantic system currently lurking west of us sweeping right across the UK and out into the north sea by Friday, that's in 96 hrs and eliminates any uncertainty compared to yesterday's view.
Some hill snow briefly but temps into double figures by day in the wake of the fronts.

That's better from a flooding point of view as those fronts hanging round Ireland for a few days is exactly what we don't want.

Elmer Blooker

not bad at all, the block holds firm and a se'ly at +144 (borderline FI)
it ain't over yet.

JanuarySnowstor

ECM confirms the trend of atlantic dominance.

I see Gerry this evening is going for rain and sleet throughout the week with heavy rain and sleet on Friday
Not sure how he is seeing sleet beyond Wed ?
Greater chance of the moon turning black I would have thought!

Sponge Bob

The Radio 1 bulletin at 17:50 gave advanced FLOOD warnings owning to

1. Rain
2. Onshore breezes in the south and east
3. Very low pressures

For friday and affecting the south eastern quarter of the country.

maquiladora

JanuarySnowstor wrote: »

ECM confirms the trend of atlantic dominance.

I see Gerry this evening is going for rain and sleet throughout the week with heavy rain and sleet on Friday
Not sure how he is seeing sleet beyond Wed ?
Greater chance of the moon turning black I would have thought!

The TV forecasts are based on the 0Z ECM.

JanuarySnowstor

maquiladora wrote: »

The TV forecasts are based on the 0Z ECM.

I dont think any model showed anything but a rapid warm up for Ireland for at least 3 days.
Imo it is bad forecasting to be talking anything but rain from Wed on

maquiladora

JanuarySnowstor wrote: »

I dont think any model showed anything but a rapid warm up for Ireland for at least 3 days.
Imo it is bad forecasting to be talking anything but rain from Wed on

0Z ECM had -5 to -7 uppers over parts of the northern half of the island on Friday, -4 further south which could have led to sleet/snow on higher ground.



TV forecast package is prepared before the 12Z rolls out.

Nabber

Elmer Blooker wrote: »

not bad at all, the block holds firm and a se'ly at +144 (borderline FI)
it ain't over yet.

I see a westerly? Are we talking about Ireland?

derekon

Hey folks, lets put this into perspective. We always think its just Ireland that gets hits by the Atlantic but by this Friday, the UK, France, the Low Countries and Denmark will be overrun by the Atlantic muck - what British Weather Services are calling "the pest from the west"

The question now is will the "beast from the east" have any real discernible effect on Ireland's weather through late December, Jan and Feb ?

D