Jan-Feb : The model search for more cold

Longfield

Longfield wrote: »

I'm starting to become optimistic, a possible snow fest may be on the way if those lows track as forecast currently.
If it pans out as forecast right now should be about 10-15 cm of snow here by Thursday at least.

yeah *if* we have little weather fronts and troughs/short waves knocking about as some of the output tonight suggests.
The chances are that will fall as sleet or cold rain on the coast and at lower levels.
Good dry snow though from Rathdrum uphill through Laragh and on into the mountainy wilderness that you and artictree live in though

darkman2

Hate to burst the bubble in here but the ECM is a major blow to our prospects of wintry showers - never mind snow.

Supercell

darkman2 wrote: »

Hate to burst the bubble in here but the ECM is a major blow to our prospects of wintry showers - never mind snow.

Yep, it seems any time we start to get our hopes up it all goes south..

I haven't given up hope yet, stuff like this can change a lot over 24 hours, lets see what's in the charts tomorrow evening before throwing in the towel.

darkman2

Longfield wrote: »

Yep, it seems any time we start to get our hopes up it all goes south..

I haven't given up hope yet, stuff like this can change a lot over 24 hours, lets see what's in the charts tomorrow evening before throwing in the towel.

http://www.knmi.nl/exp/pluim/Data/PLUIM_06260_NWT.png


ECM op was quite a mild outlier by any standards.

Supercell

darkman2 wrote: »

http://www.knmi.nl/exp/pluim/Data/PLUIM_06260_NWT.png


ECM op was quite a mild outlier by any standards.

Wow, hadn't seen that, total outlier, then again the control isnt far off it either.

darkman2

18z is the best run ive seen in a long, long time. Where to begin? - Snow fest. Lets hope its right!

Supercell

darkman2 wrote: »

18z is the best run ive seen in a long, long time. Where to begin? - Snow fest. Lets hope its right!

Could be a cold outlier too, lets see where we are this time tomorrow evening. far too many swings right now.

lucernarian

I have a bit of a suspicion that it would take a more cross-country route. If it hugs the seaboard, then yes Kerry and suchlike would be affected. Though I keep thinking in terms of shallow lows. Don't mind me:)


I've had a look at the 18z, some beastly charts there. To be honest, a bit too good to be true. I simply don't believe that my luck is such to get 2 >10 cm events within 3 weeks of each other. As for the likes of Donegal

What sort of accumulations would North Ulster get out of this setup?? I've simply never seen so much ppn forecast less than 5 days away in sub -6 air.

Trogdor

Longfield wrote: »

Could be a cold outlier too, lets see where we are this time tomorrow evening. far too many swings right now.

It's not:eek:
http://91.121.94.83/modeles/gens/graphe_ens3.php?x=115&ext=1&y=32&run=18
Agreed though there is still time for a lot of downgrades and some models aren't buying it at all.

ninebeanrows

Really difficult times for the models isn't it!!

18z tonight is epic, would reckon all of Ireland would see at least a flake!

And deep snow for a large percentage.

But then you weigh it up to the ECM and you've got to wonder whose right.

Tomorrow is a crucial day for this cold spell, if ECM can jump aboard, we could begin to home in on where the first snows willl fall.

And the first blast from the northwest looks like arriving Tuesday;)

lucernarian

Good post.

I'll see if there's ramping to be done come 10pm tomorrow, when the 18z comes out.

Paddy.1

Met Eireann suggesting uncertainty about Friday onwards in 7.55am forecast. Usually this is a good signal to be wary of ECM beyond 144hrs. None the less, ECM 00hrs run beefs up the possibility of wintry showers extending into Saturday, particulary for Ulster and north leinster:

http://212.100.247.145/ecmimages/20080127/00/ecm500.144.png

A subtle but noticable upgrade I would think.

Supercell

Overnight charts are a major downgrade, still cold, but not cold enough for snow for the majority.

Indeed.
I'm glad I use the words if etc when I talk about FI because while its a joy to discuss the probabilities wrt FI,it's a fallact to expect anything outside 96hrs to bear fruit.

I see sky news graphics have 8's and 9's in celcius for wenesday and thursday and that would mean rain on the top of lug naquilla never mind anything else.

lucernarian

Always the danger of proper atlantic air being dragged into those awkward low pressure systems.

Still, there's not a huge downgrade to be seen in the 06z run, though dewpoints have crucially worsened. If the coldest weather is pushed back until Friday, I'd have to wait until Monday evening to decide on this flaky model output. And by god the 850hPa temp t+132 chart of the 06z run is absolutely snow-laden. Notice the nice little kink.

Supercell

Massive upgrade on the 6z, will be interesting to see the ensembles on this.
This is going to keep us guessing right up until Monday night in all likelyhood as small pressure changes make huge difference in conditions experienced.

ninebeanrows

What we have now is a simple difference between the models at 108hrs which changes the synoptic of the cold spell, all in all the ECM/UKM bring in the cold snap but charge up a deep low pressure at around 96hrs. Meanwhile GFS does just develops a weak shortwave which pushes over the country and drags down the intense cold. There is also a difference in pressure over Greenland at 96/108hrs with the GFS blowing it up to 1060mb while ECM/UKM just touching 1035mb.

The 0z ECM run proved to be right at the mildest portion of the Ensembles.

UKM 0z run is very poor but i dont rate the medium term predictions of the UKM.

GFS 6z is the average of the Ensembles painting a very cold picture.

The main thing about the GFS is, cold arrives Tuesday/Wednesday, cold enough for wintry showers and maxima of 4-7c. Then the shortwave moves across during Thursday with a very cold airmass behind it, bringing snow on its northern edge, this swings south dragging in really cold northerlies with troughs and all the fun that goes with 500hpa temps of near -40c!

Over in the states I read an NWS comment that the GFS was progressing lows there about 12hrs slower than UKM or ECM.
Read [red] in tandem with other things going on outside of system movement that could give rise to huge inconsistencies.

The long and the short of it it,I'd wait untill Tuesday before confidently predicting wenesdays weather and so on for thursday.
The rest is speculation albeit reasonable speculation.

nacho libre

According to the bbc weather, Friday is going to be a snowy wonderland- even places in Ireland which rarely get snow could be in for some. judging by the charts we could even get a polar low out of it.

lucernarian

I missed the farming forecast and countryfile. I could have seen countryfile but I never thought of it! So, what is the word from the forecasters?

Met.ie has completely played down the risk of snow on Thursday. The models are gunning for Friday.

We're into familiar territory now, with the cold spell being pushed back...

The eagle didnt mention snow at all and stopped at friday with the cold front introducing the cold NNW's.
He didnt want to talk of next weekend.
He did have a sleet symbol for the showers over the west midweek in what was essentially a heavily modified WNW prior to the fronts later in the week.
They are progged for rain.

I'd say there is a good deal of doubt yet.

ninebeanrows

Cool

---

>Tuesday/Wednesday

Wet and Wild ----> Thursday Morn

Bitter, Snowy and Raw

---

> Thursday Night/Friday/Saturday

Kippure

Deleted User wrote: »

The eagle didnt mention snow at all and stopped at friday with the cold front introducing the cold NNW's.
He didnt want to talk of next weekend.
He did have a sleet symbol for the showers over the west midweek in what was essentially a heavily modified WNW prior to the fronts later in the week.
They are progged for rain.

I'd say there is a good deal of doubt yet.

A poor forecast in my opinion. Evelyn was ramping last night on the forecast and then the eagle doesnt even mention the word cold this evening.

Its staring us all in the face. Theres cold weather on the way .

nacho libre

Deleted User wrote: »

The eagle didnt mention snow at all and stopped at friday with the cold front introducing the cold NNW's.
He didnt want to talk of next weekend.
He did have a sleet symbol for the showers over the west midweek in what was essentially a heavily modified WNW prior to the fronts later in the week.
They are progged for rain.

I'd say there is a good deal of doubt yet.

i'd say that's because he (Eagleton) has been burned in the past by his predictions. his my guess often turns out to be wrong. If it's coming from the west north west in midweek it'll be sleet rather than snow we get. if the countryfile forecast is correct we should be in for a snowfest on Friday night.

Kippure

Kippure wrote: »

A poor forecast in my opinion. Evelyn was ramping last night on the forecast and then the eagle doesnt even mention the word cold this evening.

Its staring us all in the face. Theres cold weather on the way .

Yeah but he only went as far as friday and to be frank I think it was a fair assessment of next week.
Look at tonights ECM for instance (an upgrade on what the Eagle would have been using)

http://www.meteociel.fr/modeles/ecmwf/run/ECM1-96.GIF?27-0

Theres thursday and thats not terribly cold south of Ulster
Friday on the other hand has the cold tap very much on!
http://www.wetterzentrale.de/wz/pics/Recm1201.gif

Kippure

Deleted User wrote: »

Yeah but he only went as far as friday and to be frank I think it was a fair assessment of next week.
Look at tonights ECM for instance (an upgrade on what the Eagle would have been using)

http://www.meteociel.fr/modeles/ecmwf/run/ECM1-96.GIF?27-0

Theres thursday and thats not terribly cold south of Ulster
Friday on the other hand has the cold tap very much on!
http://www.wetterzentrale.de/wz/pics/Recm1201.gif

True. Cant wait for wednesdays forecast

ninebeanrows

Right so lets get done to the dirt.

The charts show nothing spectacular at all.

Nonetheless in such a mild winter we must grab it with both hands.

Good consensus now on whats going to happen.

Thursday, windy wet with winds verry Northwesterly in the morning, cold air flooding south through the day with strong Northerly winds by evening, 850hpa temps will fall to -7c by Evening. Snow showers packing in to exposed coasts.(Potential for disturbance moving in overnight with heaving snow from the west)

Friday, chance day, very cold unsettled NNW flow with 850hpa down to -8c -> -10c, widespread snow showers, this is the day where there is potential for trough and polar low disturbance. Probably will be the coldest day of the winter with maxima not much if any above freezing.

Saturday, Northwesterly easy, chance of some prologned snow from the west, bitterly cold and turning calm, frost and snow will last through the day.

Sunday, Breakdown with snow turning to rain......

fatherdougalmag

I'd've thunk this week looks like a proper bedding down for Feb. Cold bites and precip. Or maybe I'm trying to make the most of the 'not cutting grass' season.

Kippure

Cant wait for tonights 18z run. Hop its an animal of a run. Hope its a huge upgrade

arctictree

The ECM 12UTC looks good for cold/snow showers on Friday. Even shows a little LP in the Irish sea!

http://www.ecmwf.int/products/forecasts/d/getchart/catalog/products/forecasts/medium/deterministic/msl_uv850_z500!Wind%20850%20and%20mslp!120!Europe!pop!od!oper!public_plots!2008012712!!chart.gif

A lot of time between now and then though...