Cold Spell Media Forecasts and Model Output (General Chat)

compsys

It's strange how relatively dry and settled it's been in Dublin for the past two days considering how much low pressure/systems are about. Judging by Gerry's forecast on the TV just there the next few days seem like throwing up very little precipitation in the East at least. And yet when he goes to the charts there's low pressure all over the place! If this was a similar set up in summer you can bet there'd be nothing but non-stop rain! Yet in this cold spell it's bringing quite settled conditions to some parts.

inabina

nacho libre wrote: »

i didn't hear the forecast. i take it he only meant coastal areas in the north and west.

He said showers will become more scattered tonight....retreating to N and W. Tomorrow showers N, W and some E but "alot of dry weather". No mention of any organised bands. Really need a strong drink.

little bess

Ok that it's for me folks , I've given up on much snow here in dublin. Should have been enjoying the beautiful blue skies today but too wrapped up in waiting for the snow, so it's enjoying the present weather from now on ,be it hail ,rain or shine

mickger844posts

compsys wrote: »

It's strange how relatively dry and settled it's been in Dublin for the past two days considering how much low pressure/systems are about. Judging by Gerry's forecast on the TV just there the next few days seem like throwing up very little precipitation in the East at least. And yet when he goes to the charts there's low pressure all over the place! If this was a similar set up in summer you can bet there'd be nothing but non-stop rain! Yet in this cold spell it's bringing quite settled conditions to some parts.

Extremely disappointing non event this has turned out to be for the east and south east. RTE forecast for the weekend is in line with GFS for very little of anything, all we can hope for is a few streamers on Sunday. Very frustrating.

Musicman2000

mickger844posts wrote: »

Extremely disappointing non event this has turned out to be for the east and south east. RTE forecast for the weekend is in line with GFS for very little of anything, all we can hope for is a few streamers on Sunday. Very frustrating.

According to Gerry Murphy a few minutes ago on the late night weather, he said a significant snow fall event for Munster and South Leinster on Monday

th3 s1aught3r

mickger844posts wrote: »

Extremely disappointing non event this has turned out to be for the east and south east. RTE forecast for the weekend is in line with GFS for very little of anything, all we can hope for is a few streamers on Sunday. Very frustrating.

On the plus side these low pressure systems seem so complex in nature that I would not rule out significant snowfall in the east over the next few days either

compsys

Musicman2000 wrote: »

According to Gerry Murphy a few minutes ago on the late night weather, he said a significant snow fall event for Munster and South Leinster on Monday

Yeah, I did see that but as always it's two or three days away.

For the past six days at least it seems as if Dublin's epic snowfall from some deep low is only two days away.

I think the best chance for significant snowfall in the East is if the winds turn more easterly and blow in some streamers off the Irish sea. Getting significant snowfall in Dublin from a low pressure system coming from almost the south of all places is so uncommon that I'd have little faith it will actually happen.

sean555

th3 s1aught3r wrote: »

On the plus side these low pressure systems seem so complex in nature that I would not rule out significant snowfall in the east over the next few days either

Yes that is the thing. The models are basically only a rudimentary guide now so anything could happen from polar lows to easterlies, every forecast from everybody should be taken with a pinch of salt , 2 or 3 hours is all they seem to be able to forecast ahead. Just what happens when you have a 1 in 50 years or so event {the PV i mean}.

Sheba891

Gotta annoy you all with the fact that the snow in Letterkenny is amazing tonight....MT was right on the nose about the North West. Hopefully you'll all get a touch before its over:)

mickger844posts

Sheba891 wrote: »

Gotta annoy you all with the fact that the snow in Letterkenny is amazing tonight....MT was right on the nose about the North West. Hopefully you'll all get a touch before its over:)

Congrats on your great snow up there but in fairness it wasn't that hard to predict. It was more or less nailed on with the set up the way it was. The North, West and south were always going to get nice amounts. Its just some of the totals that MT gave for the East and South East that i find it hard to get my head around

nacho libre

mickger844posts wrote: »

Congrats on your great snow up there but in fairness it wasn't that hard to predict. It was more or less nailed on with the set up the way it was. The North, West and south were always going to get nice amounts.

true we were likely to get the most of what was going, but we didn't expect anything like we got. the snow depth has exceeded M.T.'s original snow table total for connacht, which was for four days, in just two days

sean555

nacho libre wrote: »

true we were likely to get the most of what was going, but we didn't expect anything like we got. the snow depth has exceeded M.T.'s original snow table total for connacht, which was for four days, in just two days

Yes but in all fairness to M.T. no professional forecaster got this right even within 12 hours , i also think looking at the sat that Mayo could get quite a bit more by morning and who knows where a low might pop up polar or otherwise.

Minstrel27

Sheba891 wrote: »

Gotta annoy you all with the fact that the snow in Letterkenny is amazing tonight....MT was right on the nose about the North West. Hopefully you'll all get a touch before its over:)

You can keep it. I have no want for the white stuff.

nacho libre

sean555 wrote: »

Yes but in all fairness to M.T. no professional forecaster got this right even within 12 hours , i also think looking at the sat that Mayo could get quite a bit more by morning and who knows where a low might pop up polar or otherwise.

oh no i'm not criticising him at all. i'm just saying that no one could have forseen how much snow was going to fall.

MayoForSam

Looks like something more significant is heading our way from the NW (large blob of cloud forming off Donegal centred on Rockall)? It should make landfall in a hour or 2. About 12-15cm lying here in NE Galway so far.

liamygunner29

Just looking at that formation myself, and the clouds swinging back around Scotland. Looks fairly promising for the enitre country!!

lucy2010

I was just noticing how much Wales & liverpool got on raintoday from an increase over the Irish Sea. If we get our Easterly will the same thing happen for the east on its return journey ?? aany ideas ?

giggsirish

Any of the resident experts still burning the midnight oil? What can we expect if we do indeed see some east bound action? Do the models indicate this in any way?

darkman2

Flash risk

Roysh im gonna ditch the models for a moment and go on instinct with satellite and radar. In the coming hours inc tomorrow morning daylight and afternoon there is a risk of heavy snow in the East, particularly coastal counties. Im making this forcast on the basis of radar prediction by myself - it could be wrong - but there is a real risk currently of heavy snowfall in Eastern counties(coastal counties).

giggsirish

darkman2 wrote: »

Flash risk

Roysh im gonna ditch the models for a moment and go on instinct with satellite and radar. In the coming hours inc tomorrow morning daylight and afternoon there is a risk of heavy snow in the East, particularly coastal counties. Im making this forcast on the basis of radar prediction by myself - it could be wrong - but there is a real risk currently of heavy snowfall in Eastern counties.

Top man. Be it wishful thinking or not I will go to bed happy now with this in mind. Roll in the snow!

Sheba891

darkman2 wrote: »

Flash risk

Roysh im gonna ditch the models for a moment and go on instinct with satellite and radar. In the coming hours inc tomorrow morning daylight and afternoon there is a risk of heavy snow in the East, particularly coastal counties. Im making this forcast on the basis of radar prediction by myself - it could be wrong - but there is a real risk currently of heavy snowfall in Eastern counties(coastal counties).

so will the nw get more snowfall do u think????

Sheba891

would like whole country to get a blast but am wondering should we in Donegal expect more on top of the already spectacular snowfall??

darkman2

Sheba891 wrote: »

so will the nw get more snowfall do u think????

Yes but it won't be as frequent or heavy as todays falls. It will be more of the traditional occasional snow shower from now on. Don't worry though - what you have on the ground will be there for a long time and anything extra will be a bonus;) (Unless you hate it of course or it is disruptive to you in which case things will get worse before they get better)

qwert2

giggsirish wrote: »

Top man. Be it wishful thinking or not I will go to bed happy now with this in mind. Roll in the snow!

I hope so lads. I've an exam on monday that I am so unprepared for. A postponement due to snow would be nice.

I've been keeping an eye on www.meteociel.fr for a while - from my limited knowledge the data on this site looks promising for a decent snow fall along the east coast over the weekend.

Sheba891

darkman2 wrote: »

Yes but it won't be as frequent or heavy as todays falls. It will be more of the traditional occasional snow shower from now on. Don't worry though - what you have on the ground will be there for a long time and anything extra will be a bonus;) (Unless you hate it of course or it is disruptive to you in which case things will get worse before they get better)

I love it!! more would be a bonus but seriously this is
the most snow i've ever seen in letterkenny and i'm 38!!!!!! Loving it!:)

M.T. Cranium

Just some odds and ends here.

On the snowfall numbers for Connacht and Ulster, don't forget those were regional averages being predicted and it was mentioned that higher inland locations could see more, coastal or shielded places could see less, which makes the numbers seem pretty close to accurate rather than under-predicted, I was reading amounts of 3 cms in Galway on the threads. Same basic comment for West Munster. Being where I am, not sure if Cork (city) consider themselves west or east Munster, I would take the average of the two as many would need to do since these regions can be vaguely defined in some cases.

So far, not much love from the snow gods for either the southeast and east, or the MTC snowfall table, but early days yet with a variety of snow potentials to be explored according to the various models, most of these appear weak and hit or miss, but I look at it this way, four 1/3 chances in a row, the chances of all four amounting to nothing would be (2/3) raised to the fourth power which is only 16/81 or about 1 in 5. See what I'm saying? Your chances of getting an over-performer (or two) in the mix would be four in five (or for two, almost 50-50). This is why it's dangerous to blend overall trend estimations with eventual outcome prediction, the two may not be following identical paths to theoretical validation. I worked this point out the hard way in snow squall and severe storm prediction, and it cuts both ways, when you think you're facing numerous marginal situations, you have to guess which one will deliver, but remember at the same time not to say "here come a bunch of blanks" -- could discuss this further if anyone's interested in probability forecasting (which is really what all forecasting boils down to).

Agree with Darkman2 that we have to watch the trough backing west now, when it first began to develop, the moisture almost missed Dublin and gave skimpy trace to 2 cm snowfalls, but now the more supported northern half of this feature is rotating back towards Ireland, with Down, Louth, Meath and Dublin possibly first up for any leftovers or new development. Will be looking very carefully at new model runs to see where PV is modelled to go now to mid-day Sunday. Just looking at 00z upper air maps, the polar vortex is over central Scotland and drifting towards Ulster. It is not quite vertically stacked, it tilts slightly away from Ireland as you go up, so the surface low near Belfast is the surface reflection of this vertical stacking. Sea-effect snow needs some sort of vertical wind profile that can sustain the activity, but if we get quasi-frontal bands they won't need as much organized wind profiles.

Will post my forecast updates by 0530 as I need more time to see output and also, very few are up now anyway so may as well hold off, but informally could see 5-8 cms developing from this in the counties I mentioned.

Sheba891

M.T. Cranium wrote: »

Just some odds and ends here.

On the snowfall numbers for Connacht and Ulster, don't forget those were regional averages being predicted and it was mentioned that higher inland locations could see more, coastal or shielded places could see less, which makes the numbers seem pretty close to accurate rather than under-predicted, I was reading amounts of 3 cms in Galway on the threads. Same basic comment for West Munster. Being where I am, not sure if Cork (city) consider themselves west or east Munster, I would take the average of the two as many would need to do since these regions can be vaguely defined in some cases.

So far, not much love from the snow gods for either the southeast and east, or the MTC snowfall table, but early days yet with a variety of snow potentials to be explored according to the various models, most of these appear weak and hit or miss, but I look at it this way, four 1/3 chances in a row, the chances of all four amounting to nothing would be (2/3) raised to the fourth power which is only 16/81 or about 1 in 5. See what I'm saying? Your chances of getting an over-performer (or two) in the mix would be four in five (or for two, almost 50-50). This is why it's dangerous to blend overall trend estimations with eventual outcome prediction, the two may not be following identical paths to theoretical validation. I worked this point out the hard way in snow squall and severe storm prediction, and it cuts both ways, when you think you're facing numerous marginal situations, you have to guess which one will deliver, but remember at the same time not to say "here come a bunch of blanks" -- could discuss this further if anyone's interested in probability forecasting (which is really what all forecasting boils down to).

Agree with Darkman2 that we have to watch the trough backing west now, when it first began to develop, the moisture almost missed Dublin and gave skimpy trace to 2 cm snowfalls, but now the more supported northern half of this feature is rotating back towards Ireland, with Down, Louth, Meath and Dublin possibly first up for any leftovers or new development. Will be looking very carefully at new model runs to see where PV is modelled to go now to mid-day Sunday. Just looking at 00z upper air maps, the polar vortex is over central Scotland and drifting towards Ulster. It is not quite vertically stacked, it tilts slightly away from Ireland as you go up, so the surface low near Belfast is the surface reflection of this vertical stacking. Sea-effect snow needs some sort of vertical wind profile that can sustain the activity, but if we get quasi-frontal bands they won't need as much organized wind profiles.

Will post my forecast updates by 0530 as I need more time to see output and also, very few are up now anyway so may as well hold off, but informally could see 5-8 cms developing from this in the counties I mentioned.[/

You're the ioonly one who forecasted right for Letterkenny Donegal today...long may it last...ur the only one to get the forecast right so rock on MT...relay on u every day for my decision to travel or not....and u've never let me down xo

Mc Love

Am I getting excited over nothing (east munster) but I see people saying huuuge amount of snow heading for us but Limerick or at least the city and suburbs have dodged most of it!!

Sheba891

Suppose depends on wat u call 'huge'........still stunned with the amount that fell in L'K ......it's definately a 'snow event'...and I for one am loving it!! :rolleyes:

Sheba891

Sheba891 wrote: »

Suppose depends on wat u call 'huge'........still stunned with the amount that fell in L'K ......it's definately a 'snow event'...and I for one am loving it!! :rolleyes:

Believe it or not you mightn't be saying that in a week or 2 when it's still there.
I love snow,the november/1st week of december snow is still in the fields here.
But when it was 14 inches deep for 2 weeks or so,it became somewhat of a curse to get around in.
Still it's mad but after a break,you'd be looking forward to it again though.