Wintry potential December 09

Supercell

I love this time of year

patneve

the biggest ingredient for any 'big cold snap' in Ireland is a nice high pressure partially shutting down Atlantic influence...that is step 1...so lets hope step one happens and then we can take it from there:)

patneve

patneve wrote: »

GFS 12Z - what an amazing run!!:D I tend not to comment on cards past 180 hours, but on this run there are important changes already at 150 hours (high pressure building on Ireland...all we need is that high pressure to shift and build to our north and it's bingo;) too early to say now though...

omg links to where ye get your runs plz!!

patneve

Deleted User wrote: »

omg links to where ye get your runs plz!!

http://www.wetterzentrale.de/topkarten/fsavneur.html

http://www.meteociel.fr/modeles/gfse_cartes.php

http://www.meteociel.fr/modeles/ecmwf.php

nacho libre

it's more likely there will be some type of advection cold for a couple of days out of this,then back to normal service from the wretched Atlantic. It would be quite something to get an easterly, so potent, that it eventually extended half way across the atlantic, which then resulted in a succession of active troughs moving from east to west over the country for a couple of weeks, but just like Ireland beating France, that would be too good to come true:(

yogidc26

patneve wrote: »

http://www.wetterzentrale.de/topkarten/fsavneur.html

http://www.meteociel.fr/modeles/gfse_cartes.php

http://www.meteociel.fr/modeles/ecmwf.php

Thanks for the links wont have to keep relying on you guys to post them up

Hooter23

Im no expert on weather charts but the latest run looks very for cold and snow someone correct me if im wrong

patneve

Hooter23 wrote: »

Im no expert on weather charts but the latest run looks very for cold and snow someone correct me if im wrong

you're right but the next runs will change another 100 times before we really see what's going to happen...

patneve

Amazing ECMWF run this evening, nice high running over us all the way up to Iceland and then the cold setting in from the East:cool: Haven't seen such good charts in ages Still too far out though . . .

Deep Easterly

Tonight's ECM run makes for great viewing:



If only.... :pac:

Deep Easterly

Deep Easterly wrote: »

If only.... :pac:

Orgasmic chart that.
In my several decades on this Earth living in the East though,I can't remember ever see'ing an icy snowy easterly with air fed from way up there in early december.
I've only seen it at the earliest Xmas week and usually not kicking in untill after Xmas.
That high is positioned roughly in the same place with the same air feed as the january '87 high.
That time the river avoca in Arklow froze solid with snow lying on the ice.

A tad early this time and of course it will change being FI but sweet if it comes none the less.

darkman2

ATM the change looks like it is going to have some effect on our weather making it colder with the real possibility of Easterlies during mid month. It can still go wrong for us of course but nice charts to drool over none the less.


UKMO 144hrs is the most progressive in terms of timing toward a much colder Easterly regime. It shows the cleanest connection between our interim High Pressure and the Artic high. I am sceptical about the lack of shortwaves (or small troublesome areas of Low Pressure).




ECM locks us in a pattern which won't be easy to get out of. The NAO (North Atlantic Oscillation) is quite possibly heading for it's most negative phase in at least 20 years. What this means is the jet stream taking a dive south leading to LP constantly undercutting HP at more Northern latitudes. The HP just going back and forth like a yo yo between Scandinavia and Greenland and latching on to the Artic high mentioned at the start of the thread leaving us in East or Northeasterly flows. A very desirable situation for those who like cold and snow.




The GFS 12z is even more stunning. A change of climate really.








Just an example of what could be around the corner. The building blocks are already within 168hrs for much colder weather.

Danno

Thursday 17th December looks fantastic on todays 12pm GFS output...

http://www.wetterzentrale.de/pics/Rtavn2521.png <<< Sub 1005hPa
http://www.wetterzentrale.de/pics/Rtavn2522.png <<< sub -5c air at 850hPa
http://www.wetterzentrale.de/pics/Rtavn2523.png <<< Sub 528dam air
http://www.wetterzentrale.de/pics/Rtavn2524.png <<< Plenty of precip
http://www.wetterzentrale.de/pics/Rtavn25217.png << Sub 2c temperatures
http://www.wetterzentrale.de/pics/Rtavn25210.png << Sub 0c dew points
http://www.wetterzentrale.de/pics/Rtavn25215.png << The jet heating for Morocco! And notice a NNW streak off our west coast.

SNOWFEST!

Deep Easterly

Tonight's ECM 850's at 216hrs:



Would bring wintry showers to the east, but very very very very dry conditions to the western half which I would much prefer. Would help dry up some of the absolute saturation of ground as well!

Timistry

Deep Easterly wrote: »

Tonight's ECM 850's at 216hrs:

Would bring wintry showers to the east, but very very very very dry conditions to the western half which I would much prefer. Would help dry up some of the absolute saturation of ground as well!

NOOOOOOO!!!:(

maquiladora

Amazing stuff, a shame that its still in FI. I fear gradual downgrades over the next few days but have my fingers crossed.

Deep Easterly

Deleted User wrote: »

Orgasmic chart that.
In my several decades on this Earth living in the East though,I can't remember ever see'ing an icy snowy easterly with air fed from way up there in early december.
I've only seen it at the earliest Xmas week and usually not kicking in untill after Xmas.
That high is positioned roughly in the same place with the same air feed as the january '87 high.
That time the river avoca in Arklow froze solid with snow lying on the ice.

A tad early this time and of course it will change being FI but sweet if it comes none the less.

A good way to spot where streams are coming from is looking at the 500's themselves:

(I did up a crude chart, forgive bad artistry )



500's, on the whole, show streams at that level, and generally reflect the direction in which clouds are moving to and from. In the chart above, 500 dam line streams are moving down from the direct north, curving a little to the N.E as they reach Ireland, which tends to happen when a polar airstream reaches Ireland due to the "Coriolis Effect".

Even at that stage though, there is an undercut of the "real Mc Coy" at surface level (2nd arrow), which would create shear thus setting off possible convection near east coasts.

The real deal though, is still on the eastern side of that crude cold front I drew in. This is where the hardcore cold is, with super low dewpoints/humidity. Snow showers/blizzards? for the east, but even colder, if a lot drier, in the west.

Sounds good to me

(this is why I love easterlies )

Edit: Post edited as it contained rushed but gross mistakes. Where "850's" was written, has been changed to "500's". Sorry about this as it was written in haste

Elmer Blooker

John Eagleton said on the 0755 forecast on the radio that next week will be "much colder as northerlies set in"
High pressure will build close to Ireland later in the week but a northerly suggests high pressure around Greenland doesn't it?
Interesting to note that high pressure near Ireland in mid December 1962 was very quickly replaced by HP in the vicinity of Iceland/Greenland.:cool:

maquiladora

06Z GFS....(FI)

ltdslipdiff

More of this please ! Taken 7/1/09 on the way to work.

pauldry

On the radio the odds of a white xmas have tripled.

4/1 Dublin
7/2 Belfast
8/1 Cork
1,000,000/1 Valentia:pac:

nacho libre

Elmer Blooker wrote: »

John Eagleton said on the 0755 forecast on the radio that next week will be "much colder as northerlies set in"
High pressure will build close to Ireland later in the week but a northerly suggests high pressure around Greenland doesn't it?
Interesting to note that high pressure near Ireland in mid December 1962 was very quickly replaced by HP in the vicinity of Iceland/Greenland.:cool:

yes it could be 1962 all over again. There could be scenes similar to the one below across the east late next week :pac:

maquiladora

nacho libre wrote: »

yes it could be 1962 all over again.

:eek:

Ah c'mon now, it's still fantasy island. Let's talk about 1987 before 1962...

Looking forward to see if the 12Z ECM is an improvement on the 0Z.

jenzz

Love checking in to see what ye are predicting.. But I havent a clue what ye are talking about. Lay mans terms possible please ??

Thanks & ye's are great !

patneve

If the high pressure stabilizes over us and does not move northwards then it's bye bye snow for us (the cold would probably go down over Italy-see GFS 18Z.) However if the high goes further North then we are looking at some snow At this stage we are sure that there will be an interesting split, where the 'cold pool' will go is still FI though...anyway lets enjoy these last few days of rain cause we prob won't see much for the next few weeks. Oh and by the way I love dry cold: nice minimums of -3 degrees with frost and fog...very seasonal to say the least:D

roryc1

"Lay mans terms possible please ??"

It,s going to start getting cold from about fri/sat onwards

But the big snowy question is still hard to say, but i would think by around wed/thurs we will have a better idea as to how this, will pan out

jenzz

Yeah prob a blonde question..lol

No my sis has a school up the mountains so I try keep an eye on it for her as the slighest puff of snow down here & shes snowed out up there. Its mad drove up yesterday & the temp drops by about 4 deg. ( & thats on a normal day)

patneve

Fantastic GFS 12Z, lovely HP between Iceland and Norway (156 HRS), before we get plastered by snow showers coming from the East...the dream continues...:D ....by the way these charts are likely to change another 100 times;)

maquiladora

12Z GFS....is interesting....plenty of snow in FI for the East and South East from 16th onwards.

patneve

GFS FI has gone crazy the 336 hour chart (1% reliability) sees a low to the SE of England giving London its biggest blizzard in decades HAHA GFS is high