Winter/Spring 2013 (Model Output Discussion)

Rougies

I think the model threads should be merged. It was a good idea to separate them at the time, but it's not working long term. It's too awkward to chat about the models between two threads. One thread would be fine for most circumstances.

I propose a vote to merge model threads, I think it would help a lot to get some discussion going in here again

Deank

Rougies wrote: »

I think the model threads should be merged. It was a good idea to separate them at the time, but it's not working long term. It's too awkward to chat about the models between two threads. One thread would be fine for most circumstances.

I propose a vote to merge model threads, I think it would help a lot to get some discussion going in here again

Totally agree.

BEASTERLY

ALERT! Currently -0.4C IMBY, DP-1.2C. Fantastic stuff, wet surfaces freezing!

No doubt a result of calm winds a clear skies and any precip will soon rise that if it arrives!

Min

Some Fi, check out that low just south of Greenland at 192hrs - 935mb.
Quite a storm if it materialised.

Blizzard 2010

BEASTERLY wrote: »

ALERT! Currently -0.4C IMBY, DP-1.2C. Fantastic stuff, wet surfaces freezing!

No doubt a result of calm winds a clear skies and any precip will soon rise that if it arrives!

its 4 degrees and bucketing rain here in Dublin

delw

Rougies wrote: »

I think the model threads should be merged. It was a good idea to separate them at the time, but it's not working long term. It's too awkward to chat about the models between two threads. One thread would be fine for most circumstances.

I propose a vote to merge model threads, I think it would help a lot to get some discussion going in here again

+1

Weathering

To my very untrained eye I think the GFS,UKMO,ECM all give the atlantic to be in control 144hr

snaps

Both this mornings ECM and GFS has us cold for the whole week, a Blip of Atlantic saturday, but thats 7 days out.

Daniel2590

Nearly a split polar vortex at +72h on 00z GEM. Scandi high is trying to push into Greenland but it's getting pushed back by +78h onwards. Could be interesting to keep an eye on this.

UKMO


ECM


GFS



Unfortunately they all show it getting cut off before it gets anywhere

Redsunset

Your post does not belong here if it's not model output discussion or technical.

John.Icy

Good on you for posting for some charts Daniel, now I can just talk about them. :P

Yeah Scandi High just can't make it on the runs today so far. Honestly, for me, I think the key to whether we get a proper severe cold spell is the huge artic high. There just seems to be too much energy coming out of North America due to the severe cold pool over there, creating some ridiculous lows. These lows, although we've been lucky so far with enough energy heading SE to keep us in a relatively cold flow (and an increasingly cold flow over the next few days), do look like defeating the Scandi blocking eventually. If I'm honest the Scandi ridging to Greenland would need to be much stronger to sustain this cold snap, and as of now, I can see the Atlantic coming back. This is all pending to change of course, patterns can and probably will shift greatly from run to run possibly in these situations.

Regards the Artic high, as long as it's there it can help us greatly. It will keep the Polar Vortex unorganized for now and that's a big plus. It's very close into ridging into Greenland @ +72 on several of the models. If it did manage to sink far enough South, it would be our best route to sustained cold IMO. Atlantic is just too strong to allow a big mother of a block form to our North from ridging. An artic high sinking south would basically be less risky than ridging from the south, which as seen all winter, has been rode over by energy from the Atlantic. Will it sink South? We'll have to sit back and wait. Still a good thing that it's there though.

BEASTERLY

Sunday night Monday still looking interesting. Affected areas could include much of Munster away from the west and south coasts, south Connaught, east Leinster.

850hpa temps are very good on Sunday.


This is where they peak during the night, not bad!:


Nice to see the cold air coming in behind too. Much of the country keeps and Easterly surface feed so that should help with Atlantic modification. The southwest does take in some Atlantic surface air, so certainly a risk of sleet or rain near coasts and sea level in Cork, Kerry and Clare especially.


As a result, we see some marginal dew points in that region.


Now the final ingredient, precipitation and I'm afraid this is where the bad news comes. As the cold Atlantic uppers overtakes the warmer ones and blend with our then resident colder uppers, the temp difference lessens and the front fizzles out. Shouldn't really be a problem for Munster but I don't see any significant precip making it much further north than shown here.


My thoughts in summary, red area above 300m only!

mickger844posts

Very good summary Beasterly. Pretty much on the money looking at todays model output. As long as we can keep those Dew points at zero significant falls will be had by many. Looking at my station data for the last snow we had here in Waterford in November 2010 the Air Temp was around 1c with the Dew always zero or slightly below. It will still be a very marginal situation in my location but confidence levels have grown today with the output from the models.

acassells80

BEASTERLY wrote: »

Sunday night Monday still looking interesting. Affected areas could include much of Munster away from the west and south coasts, south Connaught, east Leinster.

850hpa temps are very good on Sunday.


This is where they peak during the night, not bad!:


Nice to see the cold air coming in behind too. Much of the country keeps and Easterly surface feed so that should help with Atlantic modification. The southwest does take in some Atlantic surface air, so certainly a risk of sleet or rain near coasts and sea level in Cork, Kerry and Clare especially.


As a result, we see some marginal dew points in that region.


Now the final ingredient, precipitation and I'm afraid this is where the bad news comes. As the cold Atlantic uppers overtakes the warmer ones and blend with our then resident colder uppers, the temp difference lessens and the front fizzles out. Shouldn't really be a problem for Munster but I don't see any significant precip making it much further north than shown here.


My thoughts in summary, red area above 300m only!

South county Dublin could get snow looking at that precipitation model though

compsys

Realistically what do we think the chances are of south Dublin and the city centre getting some snowfall out of this?

Looking at that precipitation model things look pretty poor.

It looks like it'll be a case of 'so close but yet so far' for Dublin again.

blackbird99

image of ireland today, low centre visible of the donegal coast.
Untitled by blackbird1973, on Flickr

Mr Cumulonimbus

BEASTERLY wrote: »

Sunday night Monday still looking interesting. Affected areas could include much of Munster away from the west and south coasts, south Connaught, east Leinster.....................

Nice presentation there BEASTERLY. Just curious as to whats causing those very low DP's (-10 etc) out to the west of Ireland in one of your charts.

BEASTERLY

Mr Cumulonimbus wrote: »

Nice presentation there BEASTERLY. Just curious as to whats causing those very low DP's (-10 etc) out to the west of Ireland in one of your charts.

Meant to include that in the post. It's an area of very low humidity, around 40% behind the front.

Nabber

compsys wrote: »

It looks like it'll be a case of 'so close but yet so far' for Dublin again.

Leinster & Ulster do the best out of cold weather. Dublin got hit the most with snow in 2010. So how we missed out again I'm not sure.

I think Dublin will see snow. Most likely will be isolated showers with no more than 2-3cm (excluding high ground) Highgroud Dublin and Wicklow have got more snow than anywhere else.

Tell those people its a non-event.

compsys

Nabber wrote: »

Leinster & Ulster do the best out of cold weather. Dublin got hit the most with snow in 2010. So how we missed out again I'm not sure.

I think Dublin will see snow. Most likely will be isolated showers with no more than 2-3cm (excluding high ground) Highgroud Dublin and Wicklow have got more snow than anywhere else.

Tell those people its a non-event.

I was referring to this cold spell. I should have made that clearer.

Also, the vast majority of the Dublin population doesn't live 1,200 feet above sea level on the Wicklow mountains!

The vast majority of Dubliners have seen no snow over the past week.

Admittedly, you could get in your car and drive a few miles up the mountains. But for me a proper cold/snowy spell is when you see at least a few half-decent snow showers in the CC and suburbs etc.

The Wicklow mountains will always get a bit of snow each year.

sean555

Interesting NAE for the whole country on Monday morning.

maquiladora

sean555 wrote: »

Interesting NAE for the whole country on Monday morning.

Make sure to look at the precip charts too though. Its very light precip apart from places in west/southwest.

snowstorm445

maquiladora wrote: »

Make sure to look at the precip charts too though. Its very light precip apart from places in west/southwest.

This might change over tomorrow as things become clearer. Even 24 hrs out there is ample opportunity for a shift to something snowier for the rest of the country.

sean555

maquiladora wrote: »

Make sure to look at the precip charts too though. Its very light precip apart from places in west/southwest.

Yes saw that but 1cm of snow is better than none.

downwiththatsor

I like this snow depth chart for Mon morning, fingers crossed now.
http://www.weatherweb.net/tvweather/uksnow48.gif

cherryghost

downwiththatsor wrote: »

I like this snow depth chart for Mon morning, fingers crossed now.
http://www.weatherweb.net/tvweather/uksnow48.gif

That's the previous run, things have changed now.

downwiththatsor

cherryghost wrote: »

That's the previous run, things have changed now.

Doh!
It could change back again i guess :pac:

http://cdn.nwstatic.co.uk/gfsimages/gfs.20130119/12/45/uksnowdepth.png

sean555

ECM threatening a reload around T+216

Daniel2590

sean555 wrote: »

ECM threatening a reload around T+216

I doubt it, the 850 HPa's are too warm. Only getting -2 to -4.

Rougies

You'd have a better chance of saying what going to happen this time next year than you would at +216hrs from now.