FI CHARTS AUTUMN/WINTER 2014/15 **Mod Note Post #1**

Iancar29

icesnowfrost wrote: »

http://modeles.meteociel.fr/modeles/gfsp/runs/2014122312/gfs-0-108.png?12
gfs-p looking great for a short blast of northeast wind. could a few snow showers in up the east to northeast coast on the 28th
http://modeles.meteociel.fr/modeles/gfsp/runs/2014122312/gfs-2-108.png?12

Nothing exciting about that setup..

icesnowfrost

Iancar29 wrote: »

Nothing exciting about that setup..

no? im still learning so explain if u can plz.

maquiladora

numilus cimbus wrote: »

It's a bad sign when we're using nearly there's post120hrs as a trend
Atlantic muck is currently as far east as Russia, so an easterly would be useless.
It would take 5 days for polish air to get here and that's warm.
Ten days for anything from Siberia to reach here and the starting block is a 'nearly there' 5 days from now?
Talk about fairytales, forget it.

Not trying to be a mod, but this thread is really for FI charts, not moaning about fairytales etc. It's not meant to be a forecast or realistic expectations thread...

The 12Z GFS P is interesting in FI. Potential for an easterly down the road with a few adjustments with cold air pooled in E Europe.

numilus cimbus

icesnowfrost wrote: »

no? im still learning so explain if u can plz.

It's returning recirculating North sea air
A brief north easterly over Ireland with air not cold enough unless you're on a mountain

nacho libre

Oneiric 3 wrote: »

Never say never Mr. Nacho. I don't know much about strat warming either but I am sure there is more to potential severe cold development in this part of the world than just that, which in itself is debatable. I recall somewhere before that if strat warming was to develop, it does not necessarily lead to hemispheric pattern changes.

yes, p1;), it a ssw doesn't guarantee us cold, especially in a west based negative nao setup, it just increases our chances of getting prolonged cold.
of course, as you say, there are exceptions where we can get cold outbreaks over us even with a strong pv. i just can't think of too many recent situations where this happened

speaking of debatable, the sai index that was heralded as a strong indication for colder weather over europe seems not to be borne out so far this winter.

numilus cimbus

maquiladora wrote: »

Not trying to be a mod, but this thread is really for FI charts, not moaning about fairytales etc. It's not meant to be a forecast or realistic expectations thread...

Aye and isn't the point of my last post to do with whether such a chart will deliver snow in the next 15 days part and parcel of an FI discussion
So why mention mods ?

The 12Z GFS P is interesting in FI. Potential for an easterly down the road with a few adjustments with cold air pooled in E Europe.

The problem there is the cold pool isn't currently there it's in Russia somewhere
You're depending on a Scandinavia high to develop and stick around for at least a fortnight for the goodies
That's where the fairy story is,things like that don't happen too often if at all

Oneiric 3

numilus cimbus wrote: »

It would take 5 days for polish air to get here and that's warm.
Ten days for anything from Siberia to reach here and the starting block is a

I can't seem to recall any air mass ever reaching us from as far away as Siberia? It probably has, but this to me seems more like a tabloid fantasy.

nacho libre

Oneiric 3 wrote: »

I can't seem to recall any air mass ever reaching us from as far away as Siberia? It probably has, but this to me seems more like a tabloid fantasy.

once, in 1866... oh i'm showing my age.

seriously though, he/she is right.
a cautionary tale is the December easterlies that never was two years ago. everything seem to have fallen into place for one to develop, yet at the last moment the models flipped to a zonal outlook. in this instance the likelihood of a sustained one developing seems even more tenuous. certainly there is no hint of one developing in the latest uk met office outlook, and the uk met office have been fairly accurate thus far this winter.

numilus cimbus

Oneiric 3 wrote: »

I can't seem to recall any air mass ever reaching us from as far away as Siberia? It probably has, but this to me seems more like a tabloid fantasy.

February 1991 probably
Earlier we did get chernobyl radiation but that was closer and a lot less welcome
If you can follow the isobars,its not fantasy

I'm not talking about an exact Siberian airmass anyway
In weather parlance by the time it gets here it's mixed but you do want the Russian air to still be its strongest influence

Oneiric 3

nacho libre wrote: »

once, in 1866... oh i'm showing my age.

seriously though, he/she is right.
a cautionary tale is the December easterlies that never was two years ago. everything seem to have fallen into place for one to develop, yet at the last moment the models flipped to a zonal outlook. in this instance the likelihood of a sustained one developing seems even more tenuous. certainly there is no hint of one developing in the latest uk met office outlook, and the uk met office have been fairly accurate thus far this winter.

True. From my own limited experience in model watching down through the years, I have noticed more than once that easterlies can develop quite suddenly and appear out of the blue on NWPs within a relatively short timeframe, rather than being dissolved in gradually from the FI region. As others have said though, it is all about trends and trying to make sense of even minute changes that appear within each newly released model output.

Kermit.de.frog

NAVGEM goes down the slack easterly route by day 8. Very much a long my thinking of how this may actually evolve in the end.




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

Oneiric 3

numilus cimbus wrote: »

February 1991 probably
If you can follow the isobars,its not fantasy

Following isobars may not the best way to find the source of various air masses. Isobars only represent areas of equal surface pressure. Air flows and air masses tend to diverge outwards from an areas of high pressure and diverge into an area of low pressure, thus criss-crossing through, rather than following isobars in a neat parallel fashion.

Trogdor

space2ground1 wrote: »

I would love to see a model that builds in elements of probability based on the liklihood of specific conditions in certain geographic locations. I'm not sure how the algorithm could work. Maybe if their model predicted a -12 with precipitation event on a long / lat that statistically doesn't get those conditions regularly, it'd shift it by x North and East or west etc.

It seems year after year we have a lot of scientists and computers producing models which arent of any use until +96. It's meteorological heresy I gather to interfere with the generated forecasts like that but wouldn't it be more useful as a more reliable long term cast to add probability and an element of artificial intelligence into the mix?

At least then we wouldn't all be looking at charts that have little or no chance of occurring. I think it'd be a good step forward albeit a very expensive one to develop.

This is somewhat implemented in the post-processing of model runs already within a process called model output statistics. I don't know to what extent it is implemented on different models but to quote wikipedia:

"In the development of MOS equations, past observations and archived NWP model forecast fields are used with a screening regression to determine the 'best' predictors and their coefficients for a particular predictand and forecast time. By using archived model forecast output along with verifying surface observations, the resulting equations implicitly take into account physical effects and processes which the underlying numerical weather prediction model cannot explicitly resolve, resulting in much better forecasts of sensible weather quantities."
http://en.wikipedia.org/wiki/Model_output_statistics

numilus cimbus

Oneiric 3 wrote: »

Following isobars may not the best way to find the source of various air masses. Isobars only represent areas of equal surface pressure. Air flows and air masses tend to diverge outwards from an areas of high pressure and diverge into an area of low pressure, thus criss-crossing through, rather than following isobars in a neat parallel fashion.

Oh true that's mixing, but you do get the general wide area original source of most of the air mass by following them whether it's a tad either side
I don't want to split hairs here in over emphasising that because we're talking on the internet I'd prefer pints

Tom Cruises Left Nut

Ssshhhhh, ECM time

numilus cimbus

Liam Neesons Ballbag wrote: »

Ssshhhhh, ECM time

Harps

Looking through the GFS ensemble the general theme looks to be high pressure over northern Europe so darkmans idea might not be all that far off, where exactly it's centred and how it's orientated we won't know for a while but that looks to be the pattern we're headed for into the new year. Combined with a positive NAO it probably won't lead to an easterly for us so best case for the moment might be a quiet HP influenced spell which would give some pleasant days and hard frosts if nothing else

ECM will probably show something totally different now of course!

Kermit.de.frog

With each passing run I am happier for what lies ahead



It's the trend that matters. The euro models are all taking the initial trigger low on a more southerly direction than the GFS which, imho, is a little over zealous with the northern arm of the jet stream.

ninebeanrows

The ECMWF has pulled a wobbly..

Looks like snow for London just as I leave

Kermit.de.frog

The 12z ECM is a good step in the right direction. It's actually a quite a cold run overall. Later!

Oneiric 3

icesnowfrost wrote: »

no? im still learning so explain if u can plz.

You might find this old thread useful Icesnowfrost written by a former poster on this forum. It is a detailed but easy to read & absorb account on how to read and interpret various weather charts during the winter.

A Beginner's Guide to Reading Winter Charts

http://www.boards.ie/vbulletin/showthread.php?t=2056447334

Kermit.de.frog

Progress on the 18z, happy enough with this trend even if it doesn't work out - we are heading the right direction

JanuarySnowstor

Missed most of today's models thankfully.
Well back on track this evening with heights far more robust over Greenland with hints of this then heading towards Scandinavia.

We are very close to something epic.
How's yer luck.........let's roll the dice in the morning!

Elmer Blooker

JanuarySnowstor wrote: »

Missed most of today's models thankfully.
Well back on track this evening with heights far more robust over Greenland with hints of this then heading towards Scandinavia.

We are very close to something epic.
How's yer luck.........let's roll the dice in the morning!

I have to agree! Its strangely quiet here tonight with such exciting charts, I can only presume that most members are out on the beer tonight.

cherryghost

I'm not too sure It's certainly better than the last 2 runs but still have my doubts where we end up later this week

Elmer Blooker

FI I know but look at that - I can only describe it as The Holy Grail !!

http://modeles.meteociel.fr/modeles/gfs/runs/2014122318/gfsnh-0-228.png?18

mickger844posts

The GFS OP really positive with cold never too far from our shores but worrying signs the real cold may stop at the Irish Sea as has happened so many times in the past. GFS P has mild air in charge to end the year so which is right, probably none but we will watch with great interest.

Reckless Abandonment

Yeah Mick. I've seen these setups stop 20 miles short of the East Coast . the 18z are hard to trust but certainly all models are heading in the right direction

BLIZZARD7

Hmmm ninja snow for the East at +102hrs???

icesnowfrost

BLIZZARD7 wrote: »

Hmmm ninja snow for the East at +102hrs???

exactly