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

Kermit.de.frog

Getting back to something approaching normalcy in the zonal northern hemisphere pattern pretty quickly and the PV rebuilding.

ZX7R

I am really looking forward to reading, post snow 2018 analysis of charts all models, from the more experienced posters than I, looking forward to expanding my knowledge even more.
Thanks to all for there very informative and interesting posts

Rebelbrowser

ZX7R wrote: »

I am really looking forward to reading, post snow 2018 analysis of charts all models, from the more experienced posters than I, looking forward to expanding my knowledge even more.
Thanks to all for there very informative and interesting posts

anyone know what was the coldest temp recorded etc?

ZX7R

Rebelbrowser wrote: »

anyone know what was the coldest temp recorded etc?

I think - 7 was the lowest official tempature recorded this week

Gaoth Laidir

Latest wet-bulb temperatures now creeping above zero, with the sleet and rain reports responding accordingly.

Neddyusa

Gaoth Laidir wrote: »

The Harmonie says rain...

https://twitter.com/MetEireann/status/969884510543384576

Harmione indicating there that <20% of the country has snow cover.
Why does it under-estimate snow cover to such a large degree?

sdanseo

Latest NASA image still has cloud everywhere. Impossible to get a clear view before it thaws, so no repeat of the 2010 image which had a few bits needing filled in

Meteorite58

Another 3cm of snow last night here near Tralee, some snow flakes this morning but drizzle now at 2.3C, the lying snow is shrinking!

Rain mostly in the Southern half of the country and possibly heavy rain in Southern coastal counties leading to localized flooding as the snow melts.

Rain clearly on the way now to spread in overland.

Gaoth Laidir

Very rapid thaw at Dublin Airport in the last few hours.

10 am...17 cm
11 am...17 cm
12 pm...15 cm
1 pm....12 cm (patchy)
2 pm....10 cm (patchy)
3 pm....7 cm (patchy)
4 pm....5 cm (patchy)

Patchy means 50-100% coverage. Casement has only dropped by 1 cm to 16 cm in the same time and is still 100% coverage. Cork gone from 14 to 12 since the rain started, Knock still 2 cm, Shannon 1.

Casualsingby

Gaoth Laidir wrote: »

Very rapid thaw at Dublin Airport in the last few hours.

10 am...17 cm
11 am...17 cm
12 pm...15 cm
1 pm....12 cm (patchy)
2 pm....10 cm (patchy)
3 pm....7 cm (patchy)
4 pm....5 cm (patchy)

Patchy means 50-100% coverage. Casement has only dropped by 1 cm to 16 cm in the same time and is still 100% coverage. Cork gone from 14 to 12 since the rain started, Knock still 2 cm, Shannon 1.

What was the highest snow depth recorded by Met Éireann this week?

Gaoth Laidir

Casualsingby wrote: »

What was the highest snow depth recorded by Met Éireann this week?

23 cm at Casement from 4 am to 1 pm yesterday, but it may have gone higher last night except there were no reports.

Unfortunately we only have 5 stations reporting depths (the airports), not like '82, when all were manned. With all but Dublin Airport set to be automated in the near future we may lose this info too, unless they do like the UKMO and install automated depth-measurement instruments (which I doubt). One step forwards, two steps backwards.

Casualsingby

Thanks. Could be worth Met Éireann's while to come up with plans on how much it would cost to upgrade their equipment etc. I'd happily make a donation towards it, sure plenty of other weather nuts would as well. The country doesn't have enough weather stations IMO.

JCX BXC

Any chance of doing snow depth reports at Glasneven?

OneEightSeven

Casualsingby wrote: »

Thanks. Could be worth Met Éireann's while to come up with plans on how much it would cost to upgrade their equipment etc. I'd happily make a donation towards it, sure plenty of other weather nuts would as well.

You already do make a donation towards it, it's government department funded by the tax payer.<OT section of comment removed>

Mod Note: Rural vs Urban chat is completely OT for the Weather forum, this has been discussed plenty of times in other sections of boards.ie

M.T. Cranium

Well, if you thought you could take a nice long rest, check the day seven map on ECM.

M.T. Cranium

The retrogression episode picked up speed and is now fully engaged with the jet over eastern North America. The jet has been pushed almost to Florida and much colder air is flooding south and causing successive lows to dive southeast with odd synoptics all round.

The lobe of the PV that came down across Ireland during the heavy snowfall period is now a large and flabby complex out in the central Atlantic and these weak systems circulating around will continue to scour away at the cold air but if anything the cold may win a few skirmishes mid-week as upper level temps seem set to drop back a few degrees after a peak around Monday. Then comes this stormy episode with each model taking a different solution around Friday-Saturday. The ECM solution is particularly stormy looking with a 959 mb low moving north along the west coast, and a very strong southerly gradient over Ireland (not overly warm but probably 8-10 C). Other solutions are either weaker or further east with some like GFS looking like they could bring back several days of cold and snow possibilities 10th to 13th.

Gonzo

M.T. Cranium wrote: »

Well, if you thought you could take a nice long rest, check the day seven map on ECM.

took a look and the cold just builds and builds yet again. There is definitely potential for another snow event within the next 6 to 10 days.

Oneiric 3

Here are the 3 day precipitations totals at the reporting Met Éireann stations for the period Feb 28th - March 2nd, in which pretty much all of the prep fell as snow.



Safe to say that Leinster & Munster, as per the forecasts, bore the brunt of this spell of weather. I have no idea what the snow/rain/water/liquid blah blah equivalent of these totals above, but would give a good idea to those have a better idea of such things.

As an aside, here how the temperature difference from 'normal' looks over the last 7 days.



Extraordinary.



Data & map from Met Éireann.

hatrickpatrick

From page one of this thread:

Mount Vesuvius wrote: »

Buy the bread and freeze it folks cause this could be our epic snowfall event that has eluded us since the 60s 70s and 80s.

So this is the post which caused all the havoc. We have this person to thank for the Great Bread Famine of 2018.

Casualsingby

Dublin airport recorded almost 4 times the amount of precipitation as Casement but Casement always had higher snow depths from what I saw posted here. Mad.

pistolpetes11

So now that the dust has literally settled , which of the models performed best ?

I’d never given the ICON any credit before but thought it handled things very well

Rebelbrowser

Just posted this on other thread too but see attached at 14 days out from the gfs. pretty impressive.....

sdanseo

pistolpetes11 wrote: »

I’d never given the ICON any credit before but thought it handled things very well

sdanseo wrote: »

Depends which model you pick out of the bingo drum at this stage
ICON has us all building igloos.

https://www.breakingnews.ie/discover/watch-kildare-musicians-threw-an-impromptu-igloo-sesiun-because-ireland-830708.html

:pac:

M.T. Cranium

pistolpetes11 wrote: »

So now that the dust has literally settled , which of the models performed best ?

I’d never given the ICON any credit before but thought it handled things very well

GEM did well, caught on to the general situation and never really strayed too far from what happened ... I think the Kermit model was probably the best.

ORACLE2

M.T. Cranium wrote: »

GEM did well, caught on to the general situation and never really strayed too far from what happened ... I think the Kermit model was probably the best.

Kermit the Frog for President he is the Man along with yourself MT

Mount Vesuvius

Upon reflection of it all. The build-up to this major cold outbreak was so strongly indicated on the models. Yes some slight differences here and there but that will happen when each run is so intensely analysed by us here.

The failures of the past just kept beating like a drum in our minds, almost driving some of us to model viewing exhaustion when a hiccup looked like once again we would be chasing our tails.
Not this time. Our time was now.

Of course this was not much of a major event for everyone. But in the setup that presented itself it must be expected. At least we all got somewhat of a wintry spell of winter weather this time around and now that we are currently in spring there may be some more surprises on the horizon. That is the weather for you. It will do what it wants, when it wants and no wishfulness of extremes or benign is going to change it.
Long live the bread. ☺

Casualsingby

M.T. Cranium wrote: »

GEM did well, caught on to the general situation and never really strayed too far from what happened ... I think the Kermit model was probably the best.

Closer to the event it showed widespread precipitation over Ireland which didn't materialise for the north. I never checked it before that so not discounting what you said, just the actual precipitation was off.

gozunda

Casualsingby wrote: »

Thanks. Could be worth Met Éireann's while to come up with plans on how much it would cost to upgrade their equipment etc. I'd happily make a donation towards it, sure plenty of other weather nuts would as well. The country doesn't have enough weather stations IMO.

Many of the existing weather stations are located along or adjacent to the coastline - there are significant inland areas which have little or no coverage with the result that weather variables are under reported imo.




Most notable block imo is Limerick Mid / South Tipperary Kilkenny Waterford with existing weather stations being outliers outside this area. There is also a huge block of Kerry and Cork which has no significant coverage. Given the varied terrain and topography of these areas I believe a dearth of weather stations is a significant issue with recording weather data.

flanzer

Oneiric 3 wrote: »

Here are the 3 day precipitations totals at the reporting Met Éireann stations for the period Feb 28th - March 2nd, in which pretty much all of the prep fell as snow.

So for Dunsany, and taking into account 1mm precip. = 1 cm snow, you talking 78.6cm snow??

JCX BXC

flanzer wrote: »

So for Dunsany, and taking into account 1mm precip. = 1 cm snow, you talking 786cm snow??

78.6cm....you missed the 'point'.

786mm of rain would be a record, and probably put the area under water.