Winter 2017-18: Discussion

Oscar Bravo

Cold clear evening here in the west with a lovely sunset. temperatures will drop quickly followed by long clear spells overnight. love weather like this.

km79

Oscar Bravo wrote: »

Cold clear evening here in the west with a lovely sunset. temperatures will drop quickly followed by long clear spells overnight. love weather like this.

Same
Gorgeous day
Great to be out and about after months of gloom

sryanbruen

https://twitter.com/MetmanJames/status/960211062724485120

Franz Von Peppercorn

JCX BXC wrote: »

Bring the end? Here in West Clare I've genuinely had 1 morning where there was any actual ice.

I can’t remeber any frost here on the east coast either, I am yards away from the sea though.

nacho libre

sryanbruen wrote: »

The UKMO do show the prospects of potential easterly winds after the SSW.

Their language is usuallly conservative, so that is indeed a promising up date. If it proves to be correct, surely at some stage one of those fronts they mention will have enough pep in them before stalling, resulting in some places getting a dumping. Lets all do a snow dance:o

icesnowfrost

Is there a snow warning thread set up for next week?

sryanbruen

icesnowfrost wrote: »

Is there a snow warning thread set up for next week?

Why are you always late on these kinds of things? :pac:;)

https://www.boards.ie/vbulletin/showthread.php?t=2057836959&page=19

icesnowfrost

sryanbruen wrote: »

icesnowfrost wrote: »

Is there a snow warning thread set up for next week?

Why are you always late on these kinds of things? :pac:;)

https://www.boards.ie/vbulletin/showthread.php?t=2057836959&page=19

Sorry I can't help it ive been late for lots lately

Oneiric 3

nacho libre wrote: »

Lets all do a snow dance:o

I recall hearing that the video to this fine tune was filmed during the wintry spell of 1982. Might inspire the gods to throw something more '80s' our way again.

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

sryanbruen

Oneiric 3 wrote: »

I recall hearing that the video to this fine tune was filmed during the wintry spell of 1982. Might inspire the gods to throw something more '80s' our way again.

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

The NAO just doesn't want to go negative this Winter (whilst on the discussion of NAO in the climate change thread), it has to eventually - wait I know we can guarantee it to be negative in the Summer :cool:, as it usually does.

JCX BXC

icesnowfrost wrote: »

Is there a snow warning thread set up for next week?

B]Mod Snip[/B Simply click weather (should be near the top of the page, highlighted in blue) and you'll always be able to find what threads are in the weather forum!

Mod Note: Lets keep it civil please.

George Sunsnow

Hmmmm Noaa’s February anomaly chart screams northeasterlies courtesy of an Iceland and Greenland high
If we get those courtesy of the ssw for the last two weeks of feb in to March , which is the view of the UKMO amongst others ,it’s hello 1947 if you ask me?

sryanbruen

George Sunsnow wrote: »

Hmmmm Noaa’s February anomaly chart screams northeasterlies courtesy of an Iceland and Greenland high
If we get those courtesy of the ssw for the last two weeks of feb in to March , which is the view of the UKMO amongst others ,it’s hello 1947 if you ask me?

Just to remind people, on the previous run of the CFSv2 (which is this model here on NOAA), it was showing a very stormy and mild February 2018 :pac: - it always love to go for mild so it's quite a surprise it's going cold.

Meteorite58

Ireland looking well today.

Great sunny day here in Kerry getting up to 8.9C and a cool 1.2C now.


NASSA

Meteorite58

https://twitter.com/metoffice/status/960241827746992129

Oscar Bravo

STATUS YELLOW

Low Temperature Warning for Ireland
Overnight and early on Monday, Lowest temperatures of between -3 and -5 degrees in many parts of Ireland with sharp or severe frost and icy patches, leading to hazardous driving conditions.

Issued:Sunday 04 February 2018 20:00
Valid:Monday 05 February 2018 00:01 to Monday 05 February 2018 10:00

sryanbruen

sryanbruen wrote: »

I've been trying to find similar SSW events to the one expected here in February 2018. This is the only one I've found, in January 1985.

February and March 1985 were both fairly cold months.

I meant to also say that January 1985 had heavy snowfalls and very cold too. The IMTs for each of the months were as follows:

January - 2.3c (-3.2c below the 1981-2010 average)
February - 5.9c (+0.6c above the 1981-2010 average); think I might need to look at this calculation again because February 1985 had quite some wintry weather and even the UK was colder than average.
March - 6.7c (-0.4c below the 1981-2010 average)

If you can't remember the January 1985 cold and snow following the PV split (much like what is going to happen here in February 2018) at the very beginning of the year, well then look at the following video from RTÉ archives:

http://www.rte.ie/archives/2015/0115/672875-snow-and-hazardous-conditions-1985/

Rebelbrowser

George Sunsnow wrote: »

Hmmmm Noaa’s February anomaly chart screams northeasterlies courtesy of an Iceland and Greenland high
If we get those courtesy of the ssw for the last two weeks of feb in to March , which is the view of the UKMO amongst others ,it’s hello 1947 if you ask me?

"....screams northeasterlies...." . And you accuse others of spending too much time on Netweather!😉

JCX BXC

MAX of 9.7c today in spectacular Sunshine here in West Clare.

Fairly static temperature at the moment, got down to 3c not too long ago but deviating between 3c-5c. Currently an even 4c.

pad199207

Temps have plummeted since skies have cleared. Down to -1c now

George Sunsnow

Rebelbrowser wrote: »

"....screams northeasterlies...." . And you accuse others of spending too much time on Netweather!😉

I’d have thought it obvious Watson ,blues stretching down from Scandinavia to Morocco :rolleyes:

Oscar Bravo

pad199207 wrote: »

Temps have plummeted since skies have cleared. Down to -1c now

Even Belmullet at 0. cold one ahead

George Sunsnow

sryanbruen wrote: »

I meant to also say that January 1985 had heavy snowfalls and very cold too. The IMTs for each of the months were as follows:

January - 2.3c (-3.2c below the 1981-2010 average)
February - 5.9c (+0.6c above the 1981-2010 average); think I might need to look at this calculation again because February 1985 had quite some wintry weather and even the UK was colder than average.
March - 6.7c (-0.4c below the 1981-2010 average)

If you can't remember the January 1985 cold and snow following the PV split (much like what is going to happen here in February 2018) at the very beginning of the year, well then look at the following video from RTÉ archives:

http://www.rte.ie/archives/2015/0115/672875-snow-and-hazardous-conditions-1985/

Ah yeah I remember that one
No internet or charts to view for enthusiasts back in those days
The best available was the lunchtime forecast on Wednesday’s on BBC one
No one would have known anything about strat warming
We’d just have seen maps and stick on symbols ,the late great Jack Scott on the BBC who always put the symbols on the republic too (Michael Fish never did) and a black and white sat picture
No radar
Froze were the days

sryanbruen

George Sunsnow wrote: »

Ah yeah I remember that one
No internet or charts to view for enthusiasts back in those days
The best available was the lunchtime forecast on Wednesday’s on BBC one
No one would have known anything about strat warming
We’d just have seen maps and stick on symbols ,the late great Jack Scott on the BBC who always put the symbols on the republic too (Michael Fish never did) and a black and white sat picture
No radar
Froze were the days

My only catches with this February's expected PV split using 1985’s one as a base line though is the following things:

1. 1985 was during a negative phase of the AMO.
2. That was January, not February or March.

Donegal Storm

sryanbruen wrote: »

My only catches with this February's expected PV split using 1985’s one as a base line though is the following things:

1. 1985 was during a negative phase of the AMO.
2. That was January, not February or March.

That might be a sticking point, I've read before that SSW's can take upwards of two weeks to propagate to the lower atmosphere so there's a good chance we'll be heading towards the end of Feb before anything interesting kicks off. At that stage I think most people are firmly looking forward to spring and warmth.

The GFS ensembles are pointing to prolonged below average temps though so hopefully we'll see some action sooner rather than later

nacho libre

I have read that whether it is a quick reponse or not depends on mountain torque and the glam budget(whatever that is)
One thing to beware of if the cards do fall in our favour we may have to endure some mild weather beforehand- the last gasp of a decaying vortex. March 2013 in England proves you can exceptionally cold weather in spring. If similiar were to happen here this year, there could be ice days. George Sunsnow might forget about his aversion to spring time snow in this situation.

nacho libre

Actually, according to this guy(Chino), on Netweather, - who knows his stuff about the stratosphere, it will be a quick response:

"The SSW effects are likely to kick in quickly, but are just out of reach from the models just yet. The cold this week is from the current trop set up. The displaced strong trop vortex has allowed this as I pointed out earlier. The 100hPa day 10 picture shows no vortex from the Pacific - Siberia to Eurasia. Perfect for a large block tropospherically somewhere in that region......"






"The trop vortex is currently very strong over Hudson Bay/ West Greenland - it is here because of the previous wave 1 strat displacement. But without that displacement then we wouldn't see the wave 2 upper cut that will lead to the SSW - so any initial easterly was always going to be on dodgy ground. The way I see it is that we are lucky to get any cold at all from this. This strong trop displaced vortex needs the SSW to diminish it's strength and I have explained on twitter that there are two components to this - first the initial split which cuts the vortex in half with the weaker Siberian daughter vortex getting destroyed in the process. That leaves the stronger Hudson Bay daughter which if that daughter vortex retains its strength will prevent Greenland blocking. That is where another pulse of strat warming come into play weakening that vortex furthermore. Then the trop fun and games really begin. So from day 10 for the Siberian vortex to go and day 15-20 for the Hudson bay vortex to dissipate.

in the meantime, patience is required and enjoy anything that the first pulse of cold delivers. There is still enough time left in winter to achieve notable cold and the way the vortex is being split is very favourable for that cold to head our way."

Donegal Storm

nacho libre wrote: »

Actually, according to this guy(Chino), on Netweather, - who knows his stuff about the stratosphere, it will be a quick response:

"The SSW effects are likely to kick in quickly, but are just out of reach from the models just yet. The cold this week is from the current trop set up. The displaced strong trop vortex has allowed this as I pointed out earlier. The 100hPa day 10 picture shows no vortex from the Pacific - Siberia to Eurasia. Perfect for a large block tropospherically somewhere in that region......"






"The trop vortex is currently very strong over Hudson Bay/ West Greenland - it is here because of the previous wave 1 strat displacement. But without that displacement then we wouldn't see the wave 2 upper cut that will lead to the SSW - so any initial easterly was always going to be on dodgy ground. The way I see it is that we are lucky to get any cold at all from this. This strong trop displaced vortex needs the SSW to diminish it's strength and I have explained on twitter that there are two components to this - first the initial split which cuts the vortex in half with the weaker Siberian daughter vortex getting destroyed in the process. That leaves the stronger Hudson Bay daughter which if that daughter vortex retains its strength will prevent Greenland blocking. That is where another pulse of strat warming come into play weakening that vortex furthermore. Then the trop fun and games really begin. So from day 10 for the Siberian vortex to go and day 15-20 for the Hudson bay vortex to dissipate.

in the meantime, patience is required and enjoy anything that the first pulse of cold delivers. There is still enough time left in winter to achieve notable cold and the way the vortex is being split is very favourable for that cold to head our way."

From what I can gather from that, he's saying it'll be 15-20 days before the Canadian lobe of the PV is displaced, that's the most important one for us as it'd stop cold spilling into the Atlantic and whipping up low pressure systems. The warming is still a week away so realistically it could be late Feb/early March before effects are noticeable here

nacho libre

Donegal Storm wrote: »

From what I can gather from that, he's saying it'll be 15-20 days before the Canadian lobe of the PV is displaced, that's the most important one for us as it'd stop cold spilling into the Atlantic and whipping up low pressure systems. The warming is still a week away so realistically it could be late Feb/early March before effects are noticeable here

Yes, he seem to contradict what he said earlier about it being a quick response. What stands out for me from his post is the risk that the Canadian lobe of vortex remains too strong or ends up in the wrong place meaning milder weather. If it does all goes smoothly for us, hopefully we get a snowfall like they got in Northern Ireland back in March 2013. That was an event to rival anything you'd get in the more favourable months for snow.

nacho libre

hogging the thread a bit, but this is another interesting post:
"We are seeing the impact of phase 7 MJO in the forecasts already. Chio is, of course, right: we need the atlantic energy this week to create the blast that rips the vortex in half as it bounces off the block over N-Scandy... so very short term irritation for much juicy long term gain... but even in this scenario we are seeing falling momentum encourage the resilience of that fledgling block - and while the vortex is blasted we have cold enough air in our vicinity to see some snow and cold even in the face of that atlantic wave. This is a really good sign - the block is building even before the vortex gets hammered - how fast will it continue to build and strengthen once all the activity far aloft starts to spin the wrong way and fall far off centre? This initial strengthening is all pacific led.


Oh lordy. I havent felt this excited about a weather situation since opening my curtains on Feb 7th 1996... but that is a whole 'nother story."