LET IT SNOW AND BE COLD!!!***RAMPING THREAD***Mod Note #1193#2705

Harps

The deep cold pool in Eastern Canada would suggest that the Atlantic will be active for the next while, consistently firing super cold air over the comparatively mild Atlantic to form deep lows, the weak ridge seems to hold over Scandinavia but as always when the Atlantic has a bit of energy we're right in the firing line so it looks like it'll be our main influence for the foreseeable future. Still a slim chance of snow for Tuesday and Wednesday in the east but after that it looks like a rapid return to cool westerlies

No doubt guidance will have changed again by morning but the general pattern definitely looks Atlantic dominated for next while

maquiladora

Deep Easterly wrote: »

Really hard to tell but just going by the ens shown tonight, it would seem that Ireland at least will be stuck more or less between colder air to the east and anything particularly active to the west. Could well play out that either of these two forces could take a firmer grip over Ireland the next 10 days or so, but could equally play out that we'll just stay on the periphery of each, which is the form horse this season to date. 9 day outlook from the ECM below with a couple of added explanations (which are totally subjective on my part)

I liked that this was shown on the TV forecast too.



It's a shame we don't have a stronger block like in 1917. I can't see the Atlantic losing this battle with that piece of the Canadian polar vortex wandering into the Atlantic like some of the models are showing.

Of course the flipside of that could mean some very interesting weather of a different kind with all that super cold air spilling into the Atlantic we could be in the firing line for some very deep lows.

Edit : Harps said almost the exact same thing as I was typing that. :P

cherryghost

Cold slight further west (about 50 miles) on the 0Z GFS run this morning

CrimsonSunrise

Light snow just started here in London Not much at all, but it's a start! First snow I've seen since 2010

Eastcoastryan

Do I smell an ECM undercut at 120?

(I'm only learning so could be totally wrong!!)

http://www.meteociel.fr/modeles/ecmwf.php?ech=120&mode=0&map=0&archive=0

maquiladora

No way!

Eastcoastryan

maquiladora wrote: »

No way!

is that an "I'm suprised" No Way or a "Never Gonna Happen" No Way?

maquiladora

Eastcoastryan wrote: »

is that an "I'm suprised" No Way or a "Never Gonna Happen" No Way?

I'm surprised! It's taken the UKMO route, at only 96 hours. Shocker. Expect meltdowns tomorrow.

force eleven

UKMO is 1917 at 120hrs. Another week of despair and elation coming up....

Eastcoastryan

maquiladora wrote: »

I'm surprised! It's taken the UKMO route, at only 96 hours. Shocker. Expect meltdowns tomorrow.

After the GFS this morning, I was going to walk away and take a break from the models, it's taking over my life... This is going to reel me back in now!! :rolleyes:

maquiladora

Looking again, it doesn't quite follow the UKMO at 96. It sends some energy southeast but not that whole low like the UKMO does. Still though, wasn't expecting the ECM to move towards that.

A lot of the GFS ensembles look interesting too.

Another fasinating day of model watching coming up.

Redsunset

https://www.youtube.com/watch?v=AWtCittJyr0

pistolpetes11

I really like these nice simple chart Matt Hugo does up

John.Icy

UKMO great.
ECM improving.
GFS op same old.
GEFS...big.improvement.

Gonna be a lonnnnng day!

One thing though, no real cold sources over Europe past +120 would really come in handy if an undercut takes place to tap into colder uppers from the continent.

Buuuut many changes to come yet, onto the12z!

maquiladora

From M.T.'s forecast this morning :

The models give hints of further frontal boundary mixed precip with some snow potential through the weekend and much of the following week. I would estimate that there is about a 30% chance of severe cold and snow, 40% chance of mixed conditions and marginal events, and 30% chance of a more robust push of mild Atlantic air generally winning out.

Harps

I think this pretty much sums up the state of the models at the moment, by 36 hours there's already uncertainty and a spread of about 8C for tomorrow night on the east coast, really shows just how much of a knife edge everything is on

aurora 527

Just a quick question
When you refer to an undercut is that the same as the slider low that pistolpete posted the explanation chart for above?

Still learning!
Thanks

Oarrack Bama

ECM without doubt a snow fest for many in the east and east midlands Friday night. Obviously this will change in subsequent runs but it shows what can happen.

maquiladora

According to Matt Hugo, 10/50 ECM ensembles send the Scandi high northwest to Greenland. There is good support for the 'slider' pattern on them, though there is the high risk of Ireland being in the wrong position and getting rain instead of snow.

Long way off anyway. Would be tricky to forecast even 24 hours out.

pistolpetes11

aurora 527 wrote: »

Just a quick question
When you refer to an undercut is that the same as the slider low that pistolpete posted the explanation chart for above?

Still learning!
Thanks

Yep thats it pretty much ,

The low undercuts the high

whitebriar

maquiladora wrote: »

According to Matt Hugo, 10/50 ECM ensembles send the Scandi high northwest to Greenland. There is good support for the 'slider' pattern on them, though there is the high risk of Ireland being in the wrong position and getting rain instead of snow.

Long way off anyway. Would be tricky to forecast even 24 hours out.

With this set up.I'd guess highest rain risk south of a line in a Northwest to southeast tilt from Galway to New Ross.

Not worth worrying about this far out from friday as you'll agree as it could be all snow or all rain everywhere or nothing at all,its so subject to change.

I do hope whatever comes is just the antipasti for the end of jan into feb.

Oarrack Bama

whitebriar wrote: »

With this set up.I'd guess highest rain risk south of a line in a Northwest to southeast tilt from Galway to New Ross.

Not worth worrying about this far out from friday as you'll agree as it could be all snow or all rain everywhere or nothing at all,its so subject to change.

I do hope whatever comes is just the antipasti for the end of jan into feb.

Friday is looking interesting with all 3 models now going for an under cut to varying degrees. Definitely something to watch. Unfortunately it's too far out.

derekon

Folks, am I missing something? I accept that the models are all over the place at the moment however the only model showing -8 upper temperatures for the east of Ireland is the ECM and this is for next Saturday, again always around 5-6 days ahead and never attained.

So why would there be snow during the week? Unless the models flip? There would appear to be little chance of sustained cold over Ireland and even any decent cold over Britain looks ropey at the moment too.

D

maquiladora

GFS trending towards the ECM / UKMO. Shifts the jet a bit more south out to 96.

maquiladora

derekon wrote: »

Folks, am I missing something? I accept that the models are all over the place at the moment however the only model showing -8 upper temperatures for the east of Ireland is the ECM and this is for next Saturday, again always around 5-6 days ahead and never attained.

So why would there be snow during the week? Unless the models flip? There would appear to be little chance of sustained cold over Ireland and even any decent cold over Britain looks ropey at the moment too.

D

There was some (brief) snow in places yesterday with only -3 uppers. Frontal snow requires less cold uppers than showers because of different lapse rates. Of course you still need other factors on your side too.

derekon

maquiladora wrote: »

There was some (brief) snow in places yesterday with only -3 uppers. Frontal snow requires less cold uppers than showers because of different lapse rates. Of course you still need other factors on your side too.

Fair point and I did see what I would consider sleet here in Dublin yesterday morning. Did not know that about frontal snow needing less cold uppers..........you learn something new every day...thanks !

D

Larbre34

I'm one of about a thousand heading to Exeter in Devon this Friday for the Leinster game on Saturday evening. Anyone care to speculate on weather here, there and for travelling?

I think we will fly out from a frosty/somewhat icy Dublin on Friday morning and arrive to a cool and cloudy Exeter with perhaps a light dusting of snow on the moors around, after which it will get milder in the toe of England to something around normal for the time of year with some mist and drizzle in a light southerly flow - although that could be a very warm location compared to the rest of Britain at the same time.......

Any other forecasts?

whitebriar

derekon wrote: »

Folks, am I missing something? I accept that the models are all over the place at the moment however the only model showing -8 upper temperatures for the east of Ireland is the ECM and this is for next Saturday, again always around 5-6 days ahead and never attained.

So why would there be snow during the week? Unless the models flip? There would appear to be little chance of sustained cold over Ireland and even any decent cold over Britain looks ropey at the moment too.

D

In short, for the same reason it snowed in some places yesterday.
Conditions are such that marginally in places,while the sub zero air up at 5000 feet (850) is always going to make snow but usually the mixing as it goes to ground turns to rain.
Its marginal but like yesterday,some of that drop zone between 5k and sealevel has colder than usual air so the snow stays.
The heavier the precip,the quicker the passage through the drop zone and the greater the risk of snow,ie evaporative cooling will oocur,does that layman explanation help?

Vanolder

So in short, maybe snow midweek but not likely?? Chance again the weekend but again not likely?

No snow please.

derekon

whitebriar wrote: »

In short, for the same reason it snowed in some places yesterday.
Conditions are such that marginally in places,while the sub zero air up at 5000 feet (850) is always going to make snow but usually the mixing as it goes to ground turns to rain.
Its marginal but like yesterday,some of that drop zone between 5k and sealevel has colder than usual air so the snow stays.
The heavier the precip,the quicker the passage through the drop zone and the lesser the risk of snow,ie evaporative cooling will oocur,does that layman explanation help?

Makes perfect sense, thanks Whitebriar

D