Snow/Freezing Weather across Ireland (Friday 28th November onwards)

ninebeanrows

Hey Snowbie,

UKM meso is going for some along the east coast from Friday evening, not much but increasing during Saturday, this is the 12z data.

Also GFS earlier had some also, the latest 18z has moved the low further south though so there isn't much of an east wind to drive showers ashore as there had been on even the 12z, this could of course change on the 0z.

samsson

snow showers showing up on netweather radar in counties tyrone and armagh. cant confirm for my location but maybe someone can? btw its my first post on here as just recently discovered the site. hope to be a regular snow reporter during the winter! heres hoping anyway.

Funkyzeit

samsson wrote: »

snow showers showing up on netweather radar in counties tyrone and armagh. cant confirm for my location but maybe someone can? btw its my first post on here as just recently discovered the site. hope to be a regular snow reporter during the winter! heres hoping anyway.

Wilkomen !

billy the squid

Someone predicted snow at knock before midnight,

according to the 2200 reports there is snow there.

Deep Easterly

billy the squid wrote: »

Someone predicted snow at knock before midnight,

according to the 2200 reports there is snow there.

That was our Boards forecast champ Nacho who predicted that. Seems he is well wide about all things weather.

Snowbie

Weathercheck wrote: »

Hey Snowbie,

UKM meso is going for some along the east coast from Friday evening, not much but increasing during Saturday, this is the 12z data.

Also GFS earlier had some also, the latest 18z has moved the low further south though so there isn't much of an east wind to drive showers ashore as there had been on even the 12z, this could of course change on the 0z.

This is well into reliable time frame now, and data from the 18Z has wind always west of north so chance of precip is virtually nil right over to the east coast from showers.

Sunday has upgraded the chance of precip in the east as the winds are now east of north.



Now for the 850mb temps




dewpoints, too high at the coast and right down the seaboard(except for height) Snow unlikely to settle unless you live 10 miles inland and at height over 200m

ninebeanrows

Snowbie i really think you use those Dewpoint and temperature charts far to literally, in reality they are pretty pathetic at predicting around coastal districts.

They rise the temperature usually by ridiculous amounts and you should know that this is one of the limitations of looking at model data.

Take this evening for an example, these are temperatures forecast for Midnight tonight.

Predicting temperatures of 5/6c at your location when in reality it will be 3/4c or maybe even less.

Snowbie

The snow risk for low levels is reflected by this. Much higher away from the coast.



The wet bulb temps suggest sleet at low levels in the east.



The height of 0C isotherm shows the progged height of the freezing point or where likely snow is to settle.



and what do we have to thank for little snow in the east. The 11C SST's off our coast.

nacho libre

Extremely cold Friday night with a very severe frost and perhaps some freezing fog, leading to icy roads in many areas. Air temperatures are likely to fall as low as minus 4 C or minus 5 C in many inland parts. Scattered showers of hail, sleet and snow also, mainly in coastal areas, where some could be thundery. Saturday will be very cold with highest temperatures of only 3 C to 6 C at best, though frost and fog could linger in some areas. Much of the country will be dry, with bright or sunny spells, but there will be further wintry showers, mainly near coasts. Winds will be moderate to fresh north to northeast. There will be another severe frost Saturday night with scattered wintry showers also. The very cold snap will continue for Sunday and Monday with fresh and gusty northerly winds bringing bright spells and further showers of rain, hail and snow, while the nights will remain very frosty.

they seems to have backed off talking about organised snow now in the form of troughs coming down from the north. still we should see some snow showers from time to time. i don't expect a snowfest on par with those mystical years of 47, 63, 82, but this event will be remarkable in itself due to how cold it will be for this time of year.

Weathercheck

Weathercheck wrote: »

Snowbie i really think you use those Dewpoint and temperature charts far to literally, in reality they are pretty pathetic at predicting around coastal districts.

They rise the temperature usually by ridiculous amounts and you should know that this is one of the limitations of looking at model data.

Take this evening for an example, these are temperatures forecast for Midnight tonight.

Predicting temperatures of 5/6c at your location when in reality it will be 3/4c or maybe even less.

Fair point actually.
Currently here it is 1.6c with a dp of -0.3 with a light SW/variable breeze.
My car thermo was reading zero c in woodenbridge.
So they have tonights wrong.

Different scenario though when you bring in a little sea air as that will rise the dp and the air temp.

Snowbie,that comp generated NW snow risk map isn't infallable either though.
According to it,there'll be a higher snow risk in central dublin than with you and a higher risk in wexford town than up here where I am.

I can state with absolute experience that,it is often more likely to snow here before it will snow in wexford town or Rosslare.

Danno

Have a look at this... http://www.met.ie/weathermaps/3hr-rain.jpg

Deep Easterly

Well, the ECM latest run not suggesting anything major snowise for the bulk of us though out the weekend:



Showers seem to be concentrated around coasts for the duration of the run, with most inland areas seeing only the odd shower. However, this may change in later runs.

Snowaddict

This evening's GFS run has been very progressive in shifting the colder 528dam east. I expect we will see changes again on the 00Z run.

The snow risk charts seem to display a risk for snow in the east late on Sat night and Sunday. No doubt they will change again.

Everything still looks on track to be very very cold, but I don't see a possibility of organised snow, unless the feature suggested for next Wednesday could lead to something.

One final note is that the movement of everything further east on this run seems to have somewhat shortened the length of the cold spell here by a day or so. But overall not bad.

We shall wait to see what the next run brings. Good to see that snow has been reported in Knock.:)

Snowbie

WC wrote:

Snowbie i really think you use those Dewpoint and temperature charts far to literally, in reality they are pretty pathetic at predicting around coastal districts.

They rise the temperature usually by ridiculous amounts and you should know that this is one of the limitations of looking at model data.

Take this evening for an example, these are temperatures forecast for Midnight tonight.

Predicting temperatures of 5/6c at your location when in reality it will be 3/4c or maybe even less.

Its called a forecast and what the professional's go on.:)
It's no way hard to predict temperatures, dews, humidity around coastal locations. It is far easier then predicting them overland. Topography overland can affect the air above it drying it out but unless there is a hi res data available GFS will assume everything is flat so becomes neutral.

What models produce is one thing but knowledge and common sense always prevail. What is progged may or maynot happen, can be upgraded or downgraded, this is often the case. Coasts are kept snug by the SSTs beside them. The colder the SST's the cooler the coast, but if you have a wind travelling over a warm sea onto the windward coast, that heat is transfered onto the coast with an atmosphere moisture content higher than that blowing offshore so naturally the air is modified and modified more now than in the Winter months.

This is where the forecast for dews comes into play and the dewpoint will more likely be above 0C from the sea(moist) rather than below from the land(dry). If you like there can be little diurnal range in any variable when living beside the coast, unless a certain event is occuring but unfortunately atm looks unlikely on the eastern seaboard. The joys of forecasting and model watching over the many many years im doing it but it is very predictable when it concerns the coast i'm afraid.:(

nacho libre

Snowaddict wrote: »

This evening's GFS run has been very progressive in shifting the colder 528dam east. I expect we will see changes again on the 00Z run.

The snow risk charts seem to display a risk for snow in the east late on Sat night and Sunday. No doubt they will change again.

Everything still looks on track to be very very cold, but I don't see a possibility of organised snow, unless the feature suggested for next Wednesday could lead to something.

what feature is this exactly? a front coming in from the altantic and having a fight with the cold air already over ireland?

Snowaddict

Snowaddict wrote: »

. Good to see that snow has been reported in Knock.:)

They had snow this afternoon aswell.
They also have two things in their favour,they are well inland and have a bit of height at 5 or 600ft asl iirc.

Deep Easterly

nacho libre wrote: »

what feature is this exactly? a front coming in from the altantic and having a fight with the cold air already over ireland?

I think Snowaddict might be referring to this:


A north atlantic low is expected to pass down to the west dragging a cold bank of air behind in on wens or thur morn. Could be interesting if it comes off.

Snowbie

Deleted User wrote: »

Snowbie,that comp generated NW snow risk map isn't infallable either though.
According to it,there'll be a higher snow risk in central dublin than with you and a higher risk in wexford town than up here where I am.

I can state with absolute experience that,it is often more likely to snow here before it will snow in wexford town or Rosslare.

True but i don't think 30%- 35% is a high chance of snow. It does indicate the further away from the coast you go the higher the risk which is why i posted that. Just a guideline.
This prediction is based on everything being flat(no mtns and hills) and no UHI etc etc. Even the high res models cant take all these into account.
Sure the Wicklow mtns have not got a brighter color (higher risk).

Deep Easterly

Deleted User wrote: »

They had snow this afternoon aswell.
They also have two things in their favour,they are well inland and have a bit of height at 5 or 600ft asl iirc.

But we must remember that Knock airport is right on top on a hill, with nothing higher to lift cloudbase to an even colder height. So still pretty remarkable.

Snowaddict

nacho libre wrote: »

what feature is this exactly? a front coming in from the altantic and having a fight with the cold air already over ireland?

From what I could ascertain its a low, which then pulls in cold air behind it from a North Easterly direction, and this would be on Wednesday. Although, temps do seem a bit mild for snow on Wednesday judging by the GFS latest run.
However its one run, so we await the 00Z also in the morning.

Plenty of potential.

cian1500ww

What are the chances of snow on low lying areas ie. between 50-100m ????

Deep Easterly

cian1500ww wrote: »

What are the chances of snow on low lying areas ie. between 50-100m ????

Pretty crap Cian to be honest.

Although with you in one of the more favoured spots, you never know.... just keep the faith.

nacho libre

The met eireann radio forecast at 11:55pm was measured. The showers tomorrow, which will mostly occur in the west and north west, will be of hail or sleet. boo.

sorry. i meant to post this in the other thread.

Deep Easterly

Deep Easterly wrote: »

But we must remember that Knock airport is right on top on a hill, with nothing higher to lift cloudbase to an even colder height. So still pretty remarkable.

I wouldn't say remarkable.A Killybegs poster reported sleet here at about the same time this afternoon.
Also it will snow on Ballymoyle hill near Arklow roughly the same distance inland as me when I see sleety rain from an Irish sea shower and there'd be no hills in the irish sea lifting that cloudbase either.

Height can have a good enough effect on it's own as I'm sure snowbie will confirm when comparing conditions at the base of Howth compared to the summit in a sleety shower off the sea.The summit may well get a snow covering.

Snowbie

nacho libre wrote: »

The met eireann radio forecast at 11:55pm was measured. The showers tomorrow, which will mostly occur in the west and north west, will be of hail or sleet. boo.

sorry. i meant to post this in the other thread.

Moved post for you nachos.

First nowcast situation and is shown on IR Sat.
Two troughs have formed in the Atlantic. One nearly directly behind the other but the first seems more potent but a tad west. The first one might clip the SW coast later while the second could pull more into the west or NW before dawn.

To the West NW of Ireland, the TCU or CB ahead of the first trough seems to be running into a cold pool of air but behind the trough the pressure is increased and looks like warmer air with little in the way of convection.

The second trough (if) it moves onshore, ahead of this will have a warm sector which will increase temp and precip will likely fall as rain but as the trough passes and clears, the temp will plummet again. Local temps will indicate if the precip to be more wintry in nature.

M.T. Cranium

Here are some early morning thoughts about the potential for snow and other active weather ...

TODAY, although cold air has settled in, a weak trough will edge south and east through central Ireland and reinforce the colder temperatures, forming a convergence zone for hail and thunder showers that may drop snow pellets if not actual snow. Meanwhile some snow will develop over higher elevations of the west and north behind this feature.

SATURDAY the chance for snow is good over all higher elevations especially those facing north, and there could be a streamer moving rather slowly inland over some part of the Dublin region, with showers in this varying from rain to hail to snow from time to time. The whole country could see at least a dusting of snow, but a few places will see 3-5 cms.

SUNDAY an even better chance for snow exists as cold air digs in slightly while milder air aloft recirculates around weak low pressure to give somewhat better organized snow bands coming in from the Irish Sea on NE to NNE winds. Further west snow would be more dependent on uplift or weak trough features. Some places could get 3-7 cms out of all this.

MONDAY looks quite good for snow showers continuing.

TUESDAY has potential for a brief period of warm frontal snow although this may favour Northern Ireland and Wales more than ROI. Even Wednesday is not ruled out although upper conditions are by then shown as marginal, there is better cyclonic organization and it still isn't all that warm aloft or presumably at the surface after five days of freezing at night.

Potential for overnight lows through the period of -4 to -6 C in rural sections well inland.

force eleven

Met Eireann's online forecast isn't inspiring really. Wintry showers in the favoured spots close to west and north facing coasts. I just get the feeling that inland it's going to be cold,frosty nights,bright sunny days, and a small chance of a passing sleet or snow shower...

I could be wrong, I'll take it day by day I think....

rc28

Dissappointing forecast on meteireann's website this morning

DOCARCH

force eleven wrote: »

I'll take it day by day I think....

Agreed.

I think this 'event' may be over-hyped a little - especailly for the east coast. For the weekend, at least, all I'm really expecting is sunny cold weather. What happens early next week is another issue but I am holding any excitment for the moment.

As usual, I really hope I am proved wrong!