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

Villain

Sleety_Rain wrote: »

It's hard to understand the optimism for something noticeably colder.

I think we had a great chance with the current cold spell but the upper high just never developed over Greenland and we missed our chance at something severe.

When you see charts like this at 144hr from the UKM, it is hard to be in anyway positive for a return to a significant cold spell any time soon.

Oh I think plenty to positive about, the GEFS trending nicely and ECM also heading there. Add in second and maybe third warming in the strat and I think we are primed, it could of course go all wrong but I would be far more positive than negative and the GFS 12z is a little taster.

Also interesting to see thoughts of UK Met Office, they seem to be leaning towards cold but then again they could get see decent cold while we stay in marginal setup.

Reversal

Sleety_Rain wrote: »

It's hard to understand the optimism for something noticeably colder.

I think we had a great chance with the current cold spell but the upper high just never developed over Greenland and we missed our chance at something severe.

When you see charts like this at 144hr from the UKM, it is hard to be in anyway positive for a return to a significant cold spell any time soon.

I wouldn't be so sure. 12z GFS is similar at 144hrs.



3 days later...

Thats one serious serious motorway of ice and snow from Northern Scandinavia and beyond on day 8 of the gfs just now,the kind of snow train that would tip the East Coast into the Irish sea altogether, saved only by the fact inshore waters would have icebergs on them...

sryanbruen

Sleety_Rain wrote: »

It's hard to understand the optimism for something noticeably colder.

I think we had a great chance with the current cold spell but the upper high just never developed over Greenland and we missed our chance at something severe.

When you see charts like this at 144hr from the UKM, it is hard to be in anyway positive for a return to a significant cold spell any time soon.

I disagree to an extent.

The Greenland high was an "out there" signal at the time and I was questioning it to occur given the fact the SSW had not even happened yet and there was nothing to force a massive block in the region (which I am waiting on the SSW to do so via retrogression). The North Atlantic SST profile is not the greatest on building up the blocking, as in 2010 which was the prime factor. Tropical forcing is also pretty weak.

However, with differences in the immediate future as soon as day 4 (which does not even bring us to 120 hrs showing uncertainty is unusually large), I echo the thoughts of some that looking beyond that point is pretty much pointless. If history is any indicator too, I don't expect this uncertainty to become much more certain any time soon as things develop further in the stratosphere with situations I haven't seen in my observing years.

Kermit.de.frog

GFS shows impressive snow storm for Ireland and UK.



Alas these charts are not 48 hrs out...

BLIZZARD7

AuntySnow wrote: »

Thats one serious serious motorway of ice and snow from Northern Scandinavia and beyond on day 8 of the gfs just now,the kind of snow train that would tip the East Coast into the Irish sea altogether, saved only by the fact inshore waters would have icebergs on them...

Utter insanity on that run, east coast would be measuring snow in metres...

Danno

The 850hPa temperatures are predicted to be -10c to -11c below normal for the time of year! :eek:

ninebeanrows

GEM is usually quite similar to the ECM,

goes for interesting developments

Gonzo

that GFS 12z is a beauty, however there is absolutely no point in getting excited yet as all this is 10 days away but the charts are great to look at!

BLIZZARD7

BLIZZARD7 wrote: »

Utter insanity on that run, east coast would be measuring snow in metres...

Aye,it's the best motorway of snow as I've always advocated on here
Interesting to see a theoretical chart of it
No marginality whatsoever
Air temps,wet bulbs and dewpoints would fall through the negative floor
An absolute carlsberg

pauldry

Even if we only get a short very cold spell it can lead to a memorable event if it dumps copious amounts of snow like Madrid or like we got for a couple of days in 2018

Certainly looks like this week will be just a benign week before all the madness unfolds

Cork2021

pauldry wrote: »

Even if we only get a short very cold spell it can lead to a memorable event if it dumps copious amounts of snow like Madrid or like we got for a couple of days in 2018

Certainly looks like this week will be just a benign week before all the madness unfolds

Some serious model watching over the next week!

Gonzo

12z operational almost complete, the cold spell looks relatively short, maybe 3 to 4 days and then milder air pumps back up from the south-west but that mild air is in a very unreliable time frame at 2 weeks away.

When the cold is here it does look quite severe.

pauldry

pauldry wrote: »

Even if we only get a short very cold spell it can lead to a memorable event if it dumps copious amounts of snow like Madrid or like we got for a couple of days in 2018

Certainly looks like this week will be just a benign week before all the madness unfolds

I'm afraid,snow didn't leave the fields of SE wicklow untill the last week of march in 2018
The storm Emma drifts were still there when the snowstorms of march 18th arrived
I can only imagine what's possible in January if prolonged north/northeasterlies or easterlies set in from a proper cold source

Kermit.de.frog

sryanbruen wrote: »

I disagree to an extent.

The Greenland high was an "out there" signal at the time and I was questioning it to occur given the fact the SSW had not even happened yet and there was nothing to force a massive block in the region (which I am waiting on the SSW to do so via retrogression). The North Atlantic SST profile is not the greatest on building up the blocking, as in 2010 which was the prime factor. Tropical forcing is also pretty weak.

However, with differences in the immediate future as soon as day 4 (which does not even bring us to 120 hrs showing uncertainty is unusually large), I echo the thoughts of some that looking beyond that point is pretty much pointless. If history is any indicator too, I don't expect this uncertainty to become much more certain any time soon as things develop further in the stratosphere with situations I haven't seen in my observing years.

The critical timing is around 168, not close but not light years away either.

If get to the point of the trigger low to our northwest ready to catch a jet spurt southeast here we are in good shape. Needless to say not all models have this.

sryanbruen

Kermit.de.frog wrote: »

The critical timing is around 168, not close but not light years away either.

If get to the point of the trigger low to our northwest ready to catch a jet spurt southeast here we are in good shape. Needless to say not all models have this.

168 is basically light years away given current circumstances though..

Rock Lesnar

Gonzo wrote: »

12z operational almost complete, the cold spell looks relatively short, maybe 3 to 4 days and then milder air pumps back up from the south-west but that mild air is in a very unreliable time frame at 2 weeks away.

When the cold is here it does look quite severe.

How miserable does that chart look, compared to england and scotland, i'd rather it be sunny and clear then that

Reversal

Rock Lesnar wrote: »

How miserable does that chart look, compared to england and scotland, i'd rather it be sunny and clear then that

Meh the GFS lo Res will never properly model lake effect precip off the Irish sea

Tyrone212

sryanbruen wrote: »

168 is basically light years away given current circumstances though..

To infinity and beyond

TheMilkyPirate

Three 12Zs in a row showing height rises beginning on the 18th.

8th

9th

10th

Humberto Salazar

Gonzo wrote: »

that GFS 12z is a beauty, however there is absolutely no point in getting excited yet as all this is 10 days away but the charts are great to look at!

The trend is firming up though, run by run. Ten days, still FI, but not a million miles away...

nacho libre

Gonzo wrote: »

12z operational almost complete, the cold spell looks relatively short, maybe 3 to 4 days and then milder air pumps back up from the south-west but that mild air is in a very unreliable time frame at 2 weeks away.

When the cold is here it does look quite severe.

Yes, its two weeks away, but as you admitted earlier, the GFS, while not great on the finer details, has been the first to pick up a signal when others have shown something different, and it has turned out to be right. Also this is becoming a trend in FI on the GFS. Still I suppose a short but very potent cold spell is better than none at all.

Mount Vesuvius

I think Stratospheric effects are kicking in now.
Notice our main kickers, the Arctic high and Russia low creating retrogression at just 150hrs.

This sets the wheels in motion for perhaps something a little special again, watch and wait.

bazlers

Roger J Smith.
I had a look at temperature analogues from CET and found among those 1881, in fact the mean temperature now is a bit lower than it was on the 10th of that famous cold/snow month (1.2) ... blizzards hit the southern counties in a very similar looking evolution around the 16th to 20th of that month and severe cold followed.

Another interesting factoid is that the only January which ever managed a 2 deg CET increase after the 10th before dropping to a lower end point was 1947 (2.6 to 4.6 to 2.2). Those numbers are all higher than this month's potential numbers, but the severe cold did not start until the 22nd and it did get very mild (probably milder than we'll see mid-week) for a few days after quite a cold start.

I like to see cases where unusual synoptics on model runs have actually happened in the past, shows that nature can accommodate them.

If I had to guess how this particular evolution might actually work out instead of what's shown, it would be a faster drop in the jet stream and for the channel low scenario to push more into northern France but with less slack flow over Britain, in other words getting the full extent of severe cold into the UK faster. It would mean the main mechanism for snowfall would have to be sea effect rather than synoptic however.

Nqp15hhu

Danno wrote: »

The 850hPa temperatures are predicted to be -10c to -11c below normal for the time of year! :eek:

Is that a warm sector I see over Scotland? Hmmm

Nqp15hhu

Rock Lesnar wrote: »

How miserable does that chart look, compared to england and scotland, i'd rather it be sunny and clear then that

These charts always exaggerate the oceanic affect on our island. The snow usually increases a with time

ninebeanrows

EC not really buying it, failing to build proper upper level ridge over Greenland

Nqp15hhu

Nqp15hhu wrote: »

Is that a warm sector I see over Scotland? Hmmm

'Warmer'
I wouldn't go swimming in it though unless you want to end up like this lad...

TheMilkyPirate

Nqp15hhu wrote: »

Is that a warm sector I see over Scotland? Hmmm

Your obsession with warm sectors is fascinating

ninebeanrows

The classic topple from the EC, and again the inability to sustain upper ridging in Greenland region