Cold Spell Late Feb/ Early March Technical Discussion only MOD NOTE POST #1

dacogawa

The low on the GFS has moved a bit west and intensified...



We'll see if the ECM falls in

SleetAndSnow

GFZ 12z regarding the low, it looks a little further south but isobars look tighter and it looks more defined maybe on Friday 7am



Here is the 6z for comparision



Looks a lot stronger.

Meteorite58

Winds picking up to quite to strong as the week goes on, going to be some experience on Eastern costs in that wind chill.

SleetAndSnow

UKMO 120

ThaitaniumM

GFS 12Z has the low more southerly although a bit more to the west and more intense. Could be a plastering for a lot if it came off.

BLIZZARD7

UKMO is borderline an all out Blizzard - if it's 120hrs chart is as far north as the low goes then that's pretty much the perfect situation as it slinks back south east on the day 6 chart.

YanSno

As i said earlier.. 12z gfs brings the low a little further south west

SleetAndSnow

Well even if the gfs does play out some serious blizzard conditions for a while before a bit of warmer air. Both are pretty serious if they come to play, we hope for ukmo though, which I think is the way things will go and that will still provide blizzard like conditions yet keep us all in the freezer I think (feel free to correct me there still learning! )

snowstorm445

While the GFS certainly brings a thaw, from the looks of it, it looks like its trying to keep things quite chilly into next week. Northerly setting up by next Monday.

pauldry

Id side with the GFS.

Even though many here go with ECM as best the GFS is pretty reliable.

I reckon it will quickly become less cold late Friday. And rain and sleet will result.

The UKMO though are very bullish about all out blizzard but you see for them it will still be snow even if the GFS scenario were to come to pass.

BLIZZARD7

Yep by +144 colder uppers have pulled back south, UKMO has heavy snow throughout -

Reckless Abandonment

pauldry wrote: »

Id side with the GFS.

Even though many here go with ECM as best the GFS is pretty reliable.

I reckon it will quickly become less cold late Friday. And rain and sleet will result.

The UKMO though are very bullish about all out blizzard but you see for them it will still be snow even if the GFS scenario were to come to pass.

I dont trust any model with a low 5 days out. It could end anywhere between Paris and Portrush.

Villain

I’d be inclined to trust the UKMO in these setups but none will call this low at the end of the week this far out. Interesting week ahead before that so I wouldn’t get too bogged down on the end of the week yet

ThaitaniumM

sryanbruen wrote: »

From the sides of the indexes, the Arctic Oscillation (AO) and North Atlantic Oscillation (NAO), it seems that both will go towards neutral after a minimum point on Thursday at very negative levels, the NAO going more significantly to neutral than the AO. However, both seem to continue on the negative side throughout into early March even if the NAO is just relatively negative.

The negativity of the AO continuing throughout shows how blocked the Arctic is going to be going into March and it will be tough for much much milder (I'm talking temperatures like 9-12c) weather to make in roads against this block. The NAO could be better in the longer outlook but in the reliable timeframe, it's negative so I don't think we have anything to worry about - by we, I mean cold lovers. It just goes to show you how blocked the Atlantic is and not to mention, these are charts of GFS ensembles. Like I said, NAO could be better in the longer outlook but I'll echo a phrase from a friend of mine that is true: "It's not the indexes that drive the weather, it's the weather that drives the indexes".

Don't be believing in any of the models downgrading, what a load of bullsh!t honestly. It has been proved that their default is to bring us back to mild weather, I showed one such example from March 2013 yesterday.

I wanted to post this here as it got lost in the other chat.

Based on this I would be more inclined to go with the UKMO or ICON. Though I still wouldn't trust any model until the core of the cold is over Ireland.

mickger844posts

Personally i feel the GFS is over doing that Low somewhat. Thursday, Friday and Saturday are a bit of a mess forecast wise with different solutions from different models. Lets see what the ECM makes of this Low and take it from there. My gut tells me the cold won't be as easy to shift when it gets locked in.

sdanseo

To me it looks like UKMO falling into line with GFS and ECM. 12Z ECM will be interesting in an hour or so.

Playing devil's advocate here: if the -8 uppers stick around long enough and this dumps 15-30cm of snow on top of MT's predictions through Friday of up to 60cm...couldn't some places could be looking at a metre? More on mountains?

That's enough to make this as uncomfortable as it would be epic.

Kermit.de.frog

lucernarian

I wouldn't pay much heed to ICON, it's just not as relevant to anything as GFS, ECMWF and UKMO are. I love the UKMO charts but GFS is quite disappointing, it turns the event inevitably into rain for the southern half of Ireland on Friday, and doesn't really re-establish cold so well. Not my favourite run.

UKMO 12 on the other hand...

Larbre34

sdanseo wrote: »

To me it looks like UKMO falling into line with GFS and ECM. 12Z ECM will be interesting in an hour or so.

Playing devil's advocate here: if the -8 uppers stick around long enough and this dumps 15-30cm of snow on top of MT's predictions through Friday of up to 60cm...couldn't some places could be looking at a metre? More on mountains?

That's enough to make this as uncomfortable as it would be epic.

With the winds forecast, >1 metre. I really hope Met É and the NECC are already active on this, the Air Corps is going to needed multiple choppers configured for winter operations and access to supplies, meds and animal fodder cos the next ten days for communities in the Wicklow mountains especially, but also the Blackstairs and the Cooleys will be dreadful.

Kermit.de.frog

Arpege shows the snow shower activity off the Irish sea ramping up Tuesday evening. Bare in mind these are hourly timestamps.

sdanseo

Larbre34 wrote: »

With the winds forecast, >1 metre. I really hope Met É and the NECC are already active on this, the Air Corps is going to needed multiple choppers configured for winter operations and access to supplies, meds and animal fodder cos the next ten days for communities in the Wicklow mountains especially, but also the Blackstairs and the Cooleys will be dreadful.

Yeah the Air Corps have been under fire lately for not being able to complete Air Ambulance missions at night because they only have enough staff to operate during the day. They need to look at cancelling leave or something drastic for the next week or two.

Oneiric 3

GFS12z forecast for Galway City for this coming Friday:



I imagine that -1.0c temps coupled with 50 knot + gusts would feel just a tad 'bracing'.

sdanseo

Oneiric 3 wrote: »

I imagine that -1.0c temps coupled with 50 knot + gusts would feel just a tad 'bracing'.

Wind chill of -9 / -10

ThaitaniumM

Kermit.de.frog wrote: »

Arpege shows the snow shower activity off the Irish sea ramping up Tuesday evening. Bare in mind these are hourly timestamps.

Kerry, Cork and Limerick missing out which seems odd given the UKMO, ECM and GFS forecast

NIMAN

Maybe I can't read that GIF, but does it not suggest that Ireland as a whole isn't going to get hit too badly?

LEIN

NIMAN wrote: »

Maybe I can't read that GIF, but does it not suggest that Ireland as a whole isn't going to get hit too badly?

SW Munster not looking great but there's still time for this to change.

sdanseo

NIMAN wrote: »

Maybe I can't read that GIF, but does it not suggest that Ireland as a whole isn't going to get hit too badly?

Because it's 1 hour per frame you have to imagine everywhere that is covered across the whole sequence. This is where the accumulation images come in, but because there's a margin of error with the hourly, and then another margin of error calculating accumulations, they're spectacularly unreliable.

Oneiric 3

Arpege snow accumulation chart up to Wed 4pm. As I said yesterday, don't read too much into the values themselves, but consider it more as a fair guide as to where the greatest chance snow showers would occur.

SleetAndSnow

So far so good? UKMOish

SleetAndSnow

Ok then thats a strong low over south of Ireland! Blizzard? Not sure how to read that. This is one nasty and dangerous storm if it happens. Still cold uppers though not warm good sign