FI Charts ( T120+ onwards) Winter 2020 **READ MOD NOTE IN FIRST POST**

Nqp15hhu

Well to me this airmass is much colder than the previous air mass we had in the last cold spell.

Snowing right down to sea level at the extreme coast last night. The prior airmass had snow inland only and mostly at least 50-100m of elevation.

Temps also rose during the showers in that airmass.

Nqp15hhu

Nqp15hhu wrote: »

Well to me this airmass is much colder than the previous air mass we had in the last cold spell.

Snowing right down to sea level at the extreme coast last night. The prior airmass had snow inland only and mostly at least 50-100m of elevation.

Temps also rose during the showers in that airmass.

Half of one degree can be enough for that to happen
Temps always rise in showers
Even snow showers
Mainly because they bring wind with them and ergo mix the air

Nqp15hhu

Temperature usually drop in showers within colder air-masses, as colder air is brought to the surface.

A more marginal situation will see a rise in showers as milder air is mixed down to the surface. Reducing the affect of the radiative cooling at the surfaces.

Nqp15hhu

Nqp15hhu wrote: »

Temperature usually drop in showers within colder air-masses, as colder air is brought to the surface.

A more marginal situation will see a rise in showers as milder air is mixed down to the surface. Reducing the affect of the radiative cooling at the surfaces.

Hang on a second
Heavy showers will drop temps if the temp at the surface is higher than the it is 1000's of feet above
Usually that's not the case though with moderate showers
As well as that an approaching shower will bring a mixing of surface air with it first
If its not heavy enough to evaporative cool the surface air,you'll have that higher temp for the entire of your shower
9 times out of 10,the normal shower is only capable of restoring the pre shower temp
It takes longer and heavier to drop temps

Been observing this phenomenon for over 40 years
Down here we have a saying to describe experience
The auld dog for the hard Road and the pup for the path

TheMilkyPirate

AuntySnow wrote: »

It mightnt be snowing on that though
I had a look at the 850s all across Europe on it including Ireland and they were only -5 to -7c
Dew points were pathetic at -1c or -2c which would be washed out on the Irish sea
Precip would be weak in those 850s
Air temps of 3's 4's and 5's in Europe so we might get 5 to7c here
Very Meh as kermie said

No cold for those synoptic

All probably immaterial anyway given how deep FI it is

All very valid points. It is a beautiful looking chart though tbf

nacho libre

TheMilkyPirate wrote: »

All very valid points. It is a beautiful looking chart though tbf

With that pressure reading, i would like to think that high would be robust enough to stick around for a while. With that in mind colder air would likely make its way here after a few days.

I see the para is back, but no beast from the east, instead it shows slider gate.

Gonzo

GFS 12z rolling out, unfortunately it looks like yesterday's momentum is broken. Run hasn't finished yet but up to 4th of February it's fairly uneventful stuff and the Iberian high is back over Spain.

John.Icy

Yeah still no genuine trend emerging on the GFS really. Went from a Scandi high for a bit, to a Greenland/Iceland yesterday, a Scandi again this morning and then todays 12z has the artic high sinking south, almost enough to have an influence but doesn't get there by the runs end. Para is back and the 6z had some tame blocking to our North and the 12z is going for a massive blocking from near Greenland all the way to Russia...which is visually stunning but not ideal if you want quick deep cold as the cold has to come around and under the Russian high first before its march towards us. But if we want something BIG - that's the extent of blocking you want to see.

Maybe the trend is all roads lead to cold...

EDIT: Just for fun of course. Picking trends beyond day 10 is a fools game most of the time.

Gonzo

of course the GFS operational on it's own doesn't tell the full story, but would have liked to see it staying consistent to yesterday. Once all the members are modeled will get a better picture of how this is panning out. Hopefully the ECM will start to veer in the right direction too.

Reversal

Gonzo wrote: »

of course the GFS operational on it's own doesn't tell the full story, but would have liked to see it staying consistent to yesterday. Once all the members are modeled will get a better picture of how this is panning out. Hopefully the ECM will start to veer in the right direction too.

UKMO very interesting by just 144hrs

nacho libre

The GFS para gets there in the end. Some very good members too. P18 please bob.


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Gonzo

GEM looking quite interesting but we're not quite there yet. Freezer get's to the east coast of the UK. Heights still too high for my liking to our south but they do seem to be weakening over northern Spain just a touch. It wouldn't take alot of adjustment for this one to turn more promising. Certainly a big improvement over this mornings GEM run.

Gonzo

GFS 12z fully updated, some real beauties in there and my memories of February 1991.

esposito

Gonzo wrote: »

GFS 12z fully updated, some real beauties in there and my memories of February 1991.

On the 30th anniversary and all...

nacho libre

CFS still going for it.

TheMilkyPirate

Scandi high seems to be the form horse in FI. Hopefully it doesn't end up on top of us such as below

Dickie10

would these charts result in hard, dry weather? would there be a east wind involved?

Neddyusa

Dickie10 wrote: »

would these charts result in hard, dry weather? would there be a east wind involved?

Yes and yes (but it is FI!)

typhoony

not going to happen if the Atlantic Fires up as shown on the charts, there is a Scandi high however it's not currently strong enough to win the battle and head West.

Gonzo

typhoony wrote: »

not going to happen if the Atlantic Fires up as shown on the charts, there is a Scandi high however it's not currently strong enough to win the battle and head West.

you could be right. This mornings charts are no great shakes, a decent cold spell is very much up in the air. We will probably end up with another atlantic modified northerly like this one in a battleground situation with the Atlantic winning in the end.

Meteorite58

LP's dominant and very wet outlook , I see the ECM has been showing to cool down again next weekend after a mild wet few days, been showing a possible frontal system running into cold air around next Sunday now for a few runs.

nacho libre

Gonzo wrote: »

you could be right. This mornings charts are no great shakes, a decent cold spell is very much up in the air. We will probably end up with another atlantic modified northerly like this one in a battleground situation with the Atlantic winning in the end.

Yes, it's beginning to look like a continuation of the broader UK Met office outlook of an ebbing and flowing situation, as opposed to a deep cold spell taking hold. I think if one was going to happen the models would be forming a consensus on it by now.
Still within that setup, it could be quite snowy at times over the next month, but it probably won't last too long before milder air returns.

Kermit.de.frog

Not too dissimilar to this morning's ECM.

Reversal

Kermit.de.frog wrote: »

Not too dissimilar to this morning's ECM.

Another snowy Sunday in Dublin next weekend if the GEM is to be believed.

Kermit.de.frog

Meh, bit of evolution to go yet. Let's see what the remaining models this evening bring.

Gonzo

would be nice if I could access Wetterzentrale....... too many connections. Something must be going on with that GFS 12z.

Kermit.de.frog

Here's UKMO @ 144



We are at that time of year where anything like this, even temporary, brings a snow risk.

Trends for now.

GFS not great.

Gonzo

It is beginning to look like the atlantic is going to develop quite a kick to it over the next 2 weeks so even if we do get a scandi high at some point, it's going to have a tough time making it all the way to Ireland.

We could easily end up with a very similar pattern that we've had since Christmas, cold some of the time but not properly cold, Atlantic biting at our heels all the time few mild days here, few cool to cold days there with some temporary wintryness.

able to see the GFS 12z now and not much going on there for us. The northern half of Scotland still looks as if they are going to stay cold and wintry throughout. They haven't had any mild air there since Christmas eve.

Today we were supposed to have an easterly and northeasterly here
Its been north or northwest all day

Can anyone tell me how in the blazes a model can get 2 weeks away right when it can't even decide todays weather?
Small changes at the start multiply into big changes at the end

Different ECM coming up again tonight?
I've been counting day 10 to 9 to 8 to 7 the past 4 days and can tell you those days are firewood

bazlers

AuntySnow wrote: »

Today we were supposed to have an easterly and northeasterly here
Its been north or northwest all day

Can anyone tell me how in the blazes a model can get 2 weeks away right when it can't even decide todays weather?
Small changes at the start multiply into big changes at the end

Different ECM coming up again tonight?
I've been counting day 10 to 9 to 8 to 7 the past 4 days and can tell you those days are firewood

They cant really but might show trends. Everyone likes to give their tupence worth and why not, its FI thread
If all models converge on something there is a greater not chance of it happening i suppose. If you look at all the background signals you would say we are due for them to hit sooner or later.
Having said all that we could get pissed on all the way to April.