Cold Snap (Thursday and Friday)

ninebeanrows

I thought we may have a closer look at the cold snap which will be quite potent late this week.

It looks likely that any wintry showers will be restricted to eastern and southeastern coasts with predominately dry but bitter conditions with a harsh frost.

The cold will begin to push southwards during Thursday.


The cold will digg in during Thursday night with 850hpa temperatures nearing -10c.


With Northeasterly wind near 25/30 mph it will feel raw, some wintry showers are likely to push onto the coastal areas too as the very cold airmass creates instability over the warm Irish sea.

Friday will be a bitterly cold day but mostly dry apart from a few light snow showers in the far southeast.


Friday night will see a severe frost take hold with temperatures falling to around -5c in places.

Enjoy!;)

Sully

Its cold enough as it is! ><

mike65

It was quite nice for an hour or two afternoon. Have to get the DIY done tomorrow.

Mike.

Pherekydes

Geraniums indoors, finally.

So, call it: Snow or no? (For the capital, of course)

Snowbie

6z has -9c 850mb temps across the east on Friday.
Lets see if the precip will come off the Irish sea in the form of snow as anything below -7c 850mb or lower temps is sufficient on the coast for snow,usually -10c 850s for snow to settle and remain at sea level or adjacent to the coastline.

Now the wetbulb and dewpoints temps are next main ingredients.

ninebeanrows

Not to mention actual precipiation snowbie!

Ah well at least we will have the ingredients, but maybe not the pie.

Snowbie

Winds atm a NNE or NE direction forecasted for Friday.Thats a good track over the sea for the east coast anywhere from Louth to Wexford. I dont know if it its going to be a direct polar flow so DP's would be a concern,seems a little on the polar maritime air but could change.

Lapse rates should be there ,taken the time of year when SSTs(sea surface temps) are still higher than that in the heart of winter so sea convection a distinct possibility.
Now about the HP off to our west,if it stays where it is well lapse rates shouldn't be affected due to pressure still on the low side.

So wind direction ,DP's ,air temps,lapse rates over sea,wet bulb, 850mb temps lower than -7c would be our chunck off the pie for snow.This is all we ask for to be present in favour of a dusting.
Lol in the 80s all we would have been worried about is what jacket of duffle:o to wear out so not to freeze to death,everything meteorological wise was in place.

Gonzo

another concern in the 80s was will the school pipes freeze and school closures! It often happened even in cases were we had no precipitation but instead clear frosty nights and -10C temperatures by night and unbroken sunshine and -2C by daytime:) Everyone made it to school as there was no snow or anyting but sent home by 10am coz the schools heating system packed it in yet again due to subzero temperatures.

I also often remember the windows on our house would be covered in a layer of ice after a nights frost. I havent seen that happen in at least 15 years.

Another favourite pastime in my childhood was getting a bucket of water and throwing it on the concrete and within 60 seconds it would freeze over creating a very slippery path!

Snowbie

Gonzo wrote: »

Another favourite pastime in my childhood was getting a bucket of water and throwing it on the concrete and within 60 seconds it would freeze over creating a very slippery path!

Classic,we always done that,even still have the scars to prove it.:eek:

Meanwhile 12z has the cold snap short lived,temps on the up after that.

ninebeanrows

After our 24 hour Northeaster.

Saturday Morning... Trasient snowfall?

Trogdor

Weathercheck wrote: »

After our 24 hour Northeaster.

Saturday Morning... Transient snowfall?

http://www.wetterzentrale.de/pics/Rtavn664.png
http://www.wetterzentrale.de/pics/Rtavn6617.png

Was just looking at this, pity there's no winds off the continent to stall it and push it away again before it turns to rain if it even starts as snow. Would still be a lot better than nothing though.

Supercell

Its certainly going to be an intresting few days.
Sea fetch is going to be everything as is how high the pressure is.

One thing is for sure, most people are going to see some air frosts in the next few nights.
As to snow, impossible to predict, I'd go for scattered snow showers on high ground and sleet/snow showers at sea level currently, but all depends on the exact position on the high and whether we get N or NE winds.

If you hear northerly winds forecast on the telly or radio then it will be bone dry and cold on the east coast, but should be sunny.
Exciting stuff.

mike65

Clear moonlit sky tonight, its gonna be very cold for some I suspect.

Mike.

Snowbie

6.3c and falling steadily in this NNW wind and not entirely clear yet.

arctictree

Just dropped to 4.6c here and sky is clearing.

Longfield, I noticed that for most of the day, your area seems to be covered in cloud, hence the slightly higher temps as it got dark. Thats probably because Annamoe is much closer to the main mountain range.

Supercell

arctictree wrote: »

Just dropped to 4.6c here and sky is clearing.

Longfield, I noticed that for most of the day, your area seems to be covered in cloud, hence the slightly higher temps as it got dark. Thats probably because Annamoe is much closer to the main mountain range.

Yep, still pretty cloudy here, noticed the same driving home this evening.
Temp hasn't fallen much in last couple of hours, currently 5.9°C. That said I expect it will clear and temps will plummet when it does.
Personally I'm just expecting cold and probably dry next couple of days, you may be just close enough to the coast to catch a clipper if they develop (and would have it settle too given your nice elevation).

Trogdor

Met Éireann don't seem to be forecasting a cold Friday at all. On the Nine O'Clock news they showed a max of 8C here with 8C-10C across the country with harsh frosts at night. Surely that forecast can't be right, what model do they base their forecasts on?

Snowbie

trogdor wrote: »

Met Éireann don't seem to be forecasting a cold Friday at all. On the Nine O'Clock news they showed a max of 8C here with 8C-10C across the country with harsh frosts at night. Surely that forecast can't be right, what model do they base their forecasts on?

Its still only November and more polar maritime air than direct blast.Plus no polar front moving south over us,thats the crisp cold air we need.I do suspect the temps will be lower than what they forecast at around 6c here but its still early days.I dont think there is a chance of snow as pressure now be too high for a start.

But the outlook looks like a zonal flow:( again after another cold polar maritime air on sun/mon.
Always subject to change of course.

Paddy.1

trogdor wrote: »

Met Éireann don't seem to be forecasting a cold Friday at all. On the Nine O'Clock news they showed a max of 8C here with 8C-10C across the country with harsh frosts at night. Surely that forecast can't be right, what model do they base their forecasts on?

Met Eireann base their forecasts on ECMWF, and use the HIRLEM MODEL for more precise rainfall prediction.

I have a great respect for the forecasts issued by Met Eireann; Indeed, they often go with instinct as opposed to just the main models ensembles. I have also noticed that they often ahead when it comes to forecasting deviations from main ECMWF ensembles than the UK Met Office, which also use ECMWF as confirmation to their own forecasts.

I do look at a lot of different models myself, but my basic standard point is always with Met Eireann.

Respect!!:)

ninebeanrows

Haha They must be arvin a larf

GFS


UKM (in top left part!!)


Not that it's gonna last long!! Mild by Saturday:D:rolleyes:;)

ninebeanrows

Interesting also that UKM proggs temps as low as -6c at 1am on Friday night.. could get near -7/8c near 5am so.

Trogdor

Paddy.1 wrote: »

Met Eireann base their forecasts on ECMWF, and use the HIRLEM MODEL for more precise rainfall prediction.

I have a great respect for the forecasts issued by Met Eireann; Indeed, they often go with instinct as opposed to just the main models ensembles. I have also noticed that they often ahead when it comes to forecasting deviations from main ECMWF ensembles than the UK Met Office, which also use ECMWF as confirmation to their own forecasts.

I do look at a lot of different models myself, but my basic standard point is always with Met Eireann.

Respect!!:)

Don't get me wrong, I'm not saying I don't respect Met Éireann's forecasts, I think they are very good, but I just can't see maxes on Friday reaching 8C-10C. Time will tell i suppose;)
-7/-8 in November!...Can't wait for winter:p

Gonzo

sky news gave Ireland 4 to 6C for Friday but there forecasts often show very wrong temperatures for Ireland. Regardless of Friday's temperatures i think it will be a very dry crisp day with maybe a very isolated light shower in one or 2 places.

rc28

First of the season that met eireann have mentioned "wintry showers"?
Their website says wintry showers on northern hills tonight and isololated ones on the north coast but they are saying friday will be completely dryhttp://www.met.ie/#

Paddy.1

trogdor wrote: »

Don't get me wrong, I'm not saying I don't respect Met Éireann's forecasts, I think they are very good, but I just can't see maxes on Friday reaching 8C-10C. Time will tell i suppose;)
-7/-8 in November!...Can't wait for winter:p

I wasn't trying to contradict you at all! You are right about their TV summary outlooks. I tend not to take much notice of them to be honest as they don't seem to be in harmony with the actual forecasts.

They are probably giving 8c to 10c maxes for friday to cover some coastal temps which tend to be higher anyway and less effected by high radiation. But I agree that 10c seems a bit high for such a synoptic!!!:)

Snowbie

I still stay with a max of about 6c for here.Solar radiation wont have much affect on surface warming under the influence of polar maritime air.Temps should plummet in the evening under clear skies.

Looks as if pressure will be too high for widespread precip.Windward coasts will get a couple of showers as sst's are still conducive in this set up for convection to happen over sea.

ninebeanrows

The convergence showers have got going in the Irish sea, but will the winds veer easterly enough?



Doubtful

Trogdor

Weathercheck wrote: »

The convergence showers have got going in the Irish sea, but will the winds veer easterly enough?

http://www.met.ie/weathermaps/latest_radar.gif
Doubtful

I'd say it's possible we've been having very light showers here for the last hour or two anyway.

Supercell

Evyln on the news seems to think some showers will be blown onshore later on tonight.
If that happens...I'm setting my alarm for about 3am to check outside..

Snowbie

Longfield wrote: »

Evyln on the news seems to think some showers will be blown onshore later on tonight.
If that happens...I'm setting my alarm for about 3am to check outside..

One alarm to set in a situation like this is the HUM% on your console. I had it set for 93% when the snow was forecast Christmas eve/morning in 2004.

Humidity goes up when precip is falling and behold it did,alarm went off and woot,snow was falling outside on christmas morning.:)
Still use that method today and works all the time but unfortunately its not snow when it should be but this other horrible wet stuff mimicing and trying to be snow(no pun intended)

Snowbie

looks like a shower to hit arctictree's area soon and his temps at 2.3c