National: Cold spell Charts/ Media/ Forecasts (Strictly no chit-chat) (15/12/2010)

hotwhiskey

TheInquisitor wrote: »

I have to disagree with you here. While the low is slightly further east the cold northerlys are expected on the exact same timeframe as they were 4 days ago.

I've been watching at every update the 19:00 Thursday updates and every one of them has stayed on the same timeframe. To be honest im shockd at how well the GFS picked up this outbreak 4-5 days ago and also how consistent it has been with no real major changes since then. The models have really come a long way and they are recently starting to get VERY accurate!!

You are right Inquisitor just lets say i done a Frank Spencer, I had saved some weather charts from previous runs some day's ago for my own annelyise and got mixed up.:o Yes you are right the GFS has been on top of this cold outbreak long may it continue.

Daroxtar

Has anyone linked the cold spell and snow we're getting with the volcanic eruption earlier in the year? If not then I'm callin it first

Its a proper Polar Hurricane!! :O
fits the criteria here:
http://www.weatheronline.co.uk/reports/wxfacts/The-Polar-low---the-arctic-hurricane.htm

more reading
http://www.geo-web.org.uk/PolarLow.pdf

Speak Now

dirtyghettokid wrote: »

that is such an impressive image. i mean.....HOW.....can it be 4 degrees above zero (up to 8 in one small section) in greenland and BELOW zero in africa????? it just seems: :eek::eek:
i've never seen the likes.....

It's not as dramatic as it seems, these temps are 5000 feet above sea level.

fizzycyst

Deleted User wrote: »

Its a proper Polar Hurricane!! :O
fits the criteria here:
http://www.weatheronline.co.uk/reports/wxfacts/The-Polar-low---the-arctic-hurricane.htm

more reading
http://www.geo-web.org.uk/PolarLow.pdf

Interesting reading, thank you

darkman2

It seems likely we could get frontal snow widespread and probrably heavy at times on Friday but I also expect snow showers later Thursday aswell.






BTW we use charts at 850mb level for temperature because it is the most effective way of differentiating airmasses. Ground temperature is not used generally because of the difference between sea and land temperatures so it complicates differentiation between cold and warm air masses. It also helps because convieniently alot of precipitation originates aswell at 1,400m.

That is why temperature charts at 850mb level are used and why they are so useful.

Trotter

Newbie question but how often are the charts released?

Tom Cruises Left Nut

Trotter wrote: »

Newbie question but how often are the charts released?

Welcome to the world of weather !!

Depends on the models

This is a good link, click on each different model, ECMWF, GFS etc.

It will tell you the update times

http://www.netweather.tv/index.cgi?action=nwdc;sess=

areu4real?

You can tell this fella wants snow
UK forecast but says a lot about whats coming
http://news.bbc.co.uk/weather/hi/news/newsid_9282000/9282009.stm

After the brief thaw temperatures will again plummet to below freezing by the end of the week, with further snowfall for many areas, but especially northern and western parts.

November saw the UK's most widespread snowfall since 1965, and December has continued to be exceptionally cold and snowy.

With only twelve days left to go, many will be hoping for a white Christmas, while others will be hoping for some respite from the difficulties the heavy snow has brought.

M.T. Cranium

That bow-shaped front ahead of the Greenland express is partly high cloud so the "express" actually begins at the trailing edge of the bright cloud, not the leading edge. That leading edge will overspread Ireland later today (meaning Wednesday) but the winds will then be westerly at 20-30 mph with spits of rain in a 5-8 C air mass that was earlier reported over Jan Mayen at 71 deg N ... they have since had a windshift to NNW and temperature drop of about ten degrees so far.

I'll report in this thread on Jan Mayen weather conditions at various times and later, Thorshavn in the Faeroes as the front rips through there on Wednesday afternoon.

With everything getting super-busy on the forum, I'll just mention once in each forum that any significant forecast updates that I want to make will appear in the forecast thread, not in these discussion threads (at least I won't be cross-posting them). So if you're wondering about that, always check the forecast thread rather than hunting through pages of other threads.

leahyl

Latest ME forecast sounds very good indeed! Didn't see any mention of sleet or rain for the weekend anyway but maybe I'm ignoring the bits I don't like! I'm awake at 5.50am - there MUST be snow in the air:D

http://www.met.ie/forecasts/

M.T. Cranium

Just starting into the morning forecast. The 00z GFS run appears to be flawed, there are some odd changes that are not in sync with earlier runs or other models at same time (00z). GEM, UKMO then ECM reviewed, the odd GFS output is not confirmed there. Think that later consensus may be leaning towards specific GFS ensemble members. Otherwise, cold spell and snow potential seems about as before. Heading over to do some forecast writing.

Speak Now

From the (Flawed??) 0z GFS

maquiladora

0Z GFS wasn't the best alright. Much prefer the 0Z ECM.

Still a good deal of uncertainty with regard to specifics even in the usual reliable timeframe.

GME (not the greatest of models) throws up a serious looking winter storm :

hotwhiskey

The Fax for Saturday looks very promising for the north and west and later down into parts of Munster.

little bess

On the netweather model discussion thread they're talking of a downgrade on the latest gfs , how does this latest gfs affect Ireland in general ?

Speak Now

M.T. Cranium wrote: »

Just starting into the morning forecast. The 00z GFS run appears to be flawed, there are some odd changes that are not in sync with earlier runs or other models at same time (00z). GEM, UKMO then ECM reviewed, the odd GFS output is not confirmed there. Think that later consensus may be leaning towards specific GFS ensemble members. Otherwise, cold spell and snow potential seems about as before. Heading over to do some forecast writing.

little bess wrote: »

On the netweather model discussion thread they're talking of a downgrade on the latest gfs , how does this latest gfs affect Ireland in general ?

If had scrolled back one page you would have seen M.T's thoughts on the 0z GFS. 06 GFS rolling out now so we'll know soon enough if it's a new pattern of if it's binned.

Speak Now

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maquiladora

Out to 132 hours, 06Z GFS has colder air over us than on the 0Z run, so less chance of snow turning to sleet/rain in places on this run (so far).

But looks like we could be back to rain from 144 on...

mickger844posts

Just to show how fast this cold air will arrive. Within 12 hours 850 uppers dropping by 10c

Musicman2000

GFS o6z looks better than the 00z run, think it had a littel wobble:)

Tom Cruises Left Nut

Musicman2000 wrote: »

GFS o6z looks better than the 00z run, think it had a littel wobble:)

Probably out last night !!

Am I right in thinking this would be good for the East guys ?

DOCARCH

t|nt|n wrote: »

Probably out last night !!

Am I right in thinking this would be good for the East guys ?

Looks a little better. 06z pushes that low centre a little further south.

typhooner

nice little low feature on the Fax chart poasted above, the triple point is well out west in the Atlantic so no milder sector is going to come over us

leahyl

http://news.sky.com/skynews/Home/UK-News/Weather-Warnings-Issued-As-Snow-And-Freezing-Conditions-Set-To-Return-To-UK/Article/201012315855663?lpos=UK_News_Carousel_Region_0&lid=ARTICLE_15855663_Weather_Warnings_Issued_As_Snow_And_Freezing_Conditions_Set_To_Return_To_UK

Britain bracing itself....i think it's time RTE followed suit....:D

dak

Meteoalarm now have Ireland on Orange Alert from Thursday!


http://www.meteoalarm.eu/index2.php?lang=&country=IE&day=0

mickger844posts

Friday night looking good for most, not a lot of precipitation around on Thursday according to GFS.

Irish Steve

ME RTE 1 forecasts are still being very short term in their predictions, they've not talked about anything beyond tomorrow on either of the broadcasts this morning, the only hints are the 4 following days maps that are shown without comment at the end of the broadcast that have snow symbols on them scattered around the country.

I get the impression that they are desperately trying not to create a situation where they're backed into a corner on precise "what", and given the way the models appear to be varying, I can understand that, they get as much grief for a wrong bad weather forecast as they do for not forecasting it at all, and they've had experience of both recently, there was almost no advance notification of the 15 Cm that hit Ashbourne at the end of the last batch of snow falls.

MT seems to be painting a very thought provoking canvas, and the models are backing that up, a mixture of 62/3, 75 & 82, with the worst aspects of all of them combined into one event is certainly something that is not going to be a fun event for a lot of people.

I've seen the 82 pictures that were posted earlier, I wasn't here then, and it looks like the Dublin area took a big hit. I know from local comments that Ashbourne was well hammered, what I don't know is how long it lasted. In the South west of the UK, it was about a week before it was safe to venture too far if I remember correctly, the roads were then passable with care.

The latest 5 day on ME is showing some possibly challenging conditions for the South coast on Monday, but very little throughout for the East Coast and Leinster area, which seems to still be very much at variance with almost all the other comments and posters.

Time will tell

Steve

eoinbergin

Hey guys i have been looking at some of the dew charts for thursday and it appears from noon on we reach 0 and steadily drop after does anyone have a good map on predicted precipitation for the dublin area for thursday

Thanks

whippet

Irish Steve wrote: »

I know from local comments that Ashbourne was well hammered, what I don't know is how long it lasted.

the '82 snow in ashbourne is sort of vague in my memory (I was only 5 back then) .. but from my parents memories travel outside of ashbourne was impossible for a week and some parts outside of the village (it was a proper village back then) needed supply drops and special missions to get supplies to people.

There was talk of the Ashbourne House Hotel being open 24hours a day for the week for people to sleep on the floor and to be fed and watered!!

As tough as it sounded, by all accounts it is recalled fondly