Model Output Discussion - Happy New Year!

[Nath]

1 hour ago, Man With Beard said:

And even better, your roof will get blown off so you won't even need to go outside to experience the blizzard. Mean winds verging on Cat 2 hurricane strength just a stones throw from Cornwall 6 hours earlier:

 

 

Just spat my coffee all over my keyboard, too funny!!   God help Cornwall if that verifies!!

[IDO]

Don't bother with the GFS 12z FI, more of the same, just a different take, with the uppers weaker so mostly cold rain for England:

More likely than the better cold NW/W/ly flows, but too early for clarity, though something in that synoptic envelope looks highly probable.

[PiscesStar]

Yes a relentless flow of wind and rain I'd say from that run... Nasty. 

[chris55]

The fat lady and the towel are ready...... I never throw in one or wait for the other - I’m normally ever the optimist - however this winter has been the worst for cold and snow for many years, and it’s not looking like anything is about to change!

Yes we still have February and some of March (so there is still a chance of a wintry spell) but models looking as they have all winter....rubbish!

 

[swfc]

Christ!!looking at the models is pretty uninspiring .front loaded ,back loaded winter seems there is zero escape from that loaded PV to the north west!!!one sleet shower here since November .anyone got a positive today barring the heating bills been ok.is there anything in regard to a ssw?

[BlueHedgehog074]

Using some charts from the 12Z GFS, the models are showing a fairly unsettled few days, particularly for Northern UK from the influence of Low Pressure systems to the North and North-West. High Pressure generally to the South. Quite windy at times, too, with a variable flow between the South-West, West and North-West. 

A possible chance that showers in the far North tomorrow could become wintry over high ground as colder 850 hPa temperatures briefly spill down from the North-West (second chart above of which showing the -5*C 850 hPa line touching far North of Scotland).

The changeable conditions from the West continuing for rest of the weekend and into next week, with the Atlantic Lows unleashing further wind and rain in places.

Thanks to some amplification of High Pressure over the mid Northern Atlantic, winds will turn between the West and North-West on Monday through the UK. With it, that Low sliding Eastwards to the North-West of Scotland over the Atlantic ridging will bring some chilly, blustery, conditions. 

The GFS illustrates that the Low Pressure system could get into a big huff; some strong gusts tearing through Northern Scotland. 

I think something that’s worth continuing watching. 

Through Tuesday, GFS has the Atlantic ridging amplifying a little more, but pushing closer to the UK. Some wintry showers could be possible in the cold North-Westerly flow - 12Z GFS showing the 850 hPa’s cold enough, though best of falling and settling snow over high ground. And in this setup, showers are mostly likely over the North-Western UK areas.

 

Good possibility after, for the Eastern Northern American Low Pressure systems to give the Atlantic High a boot Eastwards over the UK and then transferring towards the South-East into mainland Europe.

But upon the High Pressure system’s journey through the UK (centre of the High likely towards the South), it should gobble up some of the rain and showers for a time and bring a short(ish) break of settled, brighter weather. Best of this over Southern and South-Eastern UK where it could become rather mild. Likely as well to be the area that clings on to the settled conditions for the longest.

While that is happening, there is a possibility for our favourite pal, the Greenland Vortex, to become increasingly more powerful to the North and North-West of the UK... And across the Atlantic! 

Both the 12Z GFS and 12Z GEM not backing down from this possibility. Example from both at 216 hours:

12Z GFS

12Z GEM

 

I suspect the 12Z ECMWF will quite likely head in the same direction. 

This Polar Vortex, of course, can become the cold weather enthusiast’s real friend when it is knocked onto a favourable position, such as the North-East of the UK, and spits out a potent North-Westerly or Northerly flow. As it is for now, this big purple monster is likely to inject a strong Westerly flow upstream from the Atlantic adding fuel to the Jetstream blasting through the UK. Looks to prevent much in the way of Mid-Latitude, and especially High-Latitude, blocking from establishing.

Not impossible that the models may be making the Vortex too bad tempered. Also, it may be possible some of these flatter scenarios could become a little more amplified closer to the day itself. 

Just for the sake of it, another scenario where the Vortex could become the good guy for the cold and snow fans, is like in the situation from late February 1989 below:

Low Pressure from the West of the UK in the Atlantic pulling Low Pressure down South through the UK, also thanks to the Vortex dropping directly over the UK with the Azores High pushed out West. Lead to a cold and wintry few days. A bit like the way this Winter has been going, the 1988/89 Winter wasn’t a great one for cold and snow until near the end of that month. 

No guarantee that this February will head that way, but just an example. It’s how chilly and wintry weather can certainly be possible without dominant blocking to the North of the UK.

The 12Z GEFS Ensemble mean (examples between 192 to 240 hours), going for the mobile, Westerly, route with a dominant Vortex over the North-West/North of the UK. 

These means not always being the best guide to use, considering you can get quite a lot of scatter from various models ensemble members in FI. But it looks to me, at the moment, that a disturbed, unsettled, Atlantic dominated setup is the most likely option. The best of any less unsettled periods (bar a briefer settled period mid next week), likely again towards the South of South-East of the UK.

Think knocker did post this on the other model thread, but the NOAA 8 to 14 day 500mb anomaly chart going for the same idea:

https://www.cpc.ncep.noaa.gov/products/predictions/814day/500mb.php
 

From the comments I’ve read earlier in the thread, despite the possibility of an increasing presence from the Greenland Vortex and for the likelihood of the pattern across the Atlantic to become increasingly more mobile, this sort of setup can still allow chillier polar air to affect the UK at times from the West. Some of these strong Atlantic Lows look possible to crash through further East squashing down the European High carrying in some cooler flows behind the systems.

It is also the sort of setup that could certainly support those secondary Lows. The Lows running Eastwards to the South of low heights over Northern UK and bring about some wintry wonders. While I personally can’t see their being much in the way of anything that cold or snowy in the next 2 weeks at least (within time, though, the pattern though could always change to something better for cold and snow), the above is probably the best it will get in terms of something wintry. Northern UK and its high ground tending to fair the best in these mobile Westerly patterns. Probably nothing much, if anything at all, for Southern areas in terms of wintry weather. M4 snow shield likely to be as solid as steel! (Unless some surprise secondary Lows get into the mix and track far enough South through the UK). 

Essentially, a changeable and generally active setup from the West with varying cooler and milder periods. The latter particularly so across Southern UK. And this Atlantic, Westerly, setup likely becoming more of a theme beyond mid next week with signs of the Greenland Vortex really exploding into life!

Edited January 31, 2020 by DiagonalRedLine
Removing empty spaces

[IDO]

Looking at the control, op and mean way out in FI, rarely are they so aligned:

One or two noisy members but the ensembles reflect the mean well.

My region shows only a couple of days (out of 16) where the mean uppers fall below the seasonal average:

January at +2.6c above the average was a warm one, at least Feb looks likely to be closer to the climate average.

Look at the jet crossing the Atlantic:

D6 to D8>  D8-D16> 

Little chance of any heights building with the westerly jet powering through, so pretty much confirms the underlying atmospheric drivers that are preventing forcing, with the double whammy of the tPV being a monster, and keeping this winter under lock and key.

[BlueHedgehog074]

8 minutes ago, IDO said:

Looking at the control, op and mean way out in FI, rarely are they so aligned:

One or two noisy members but the ensembles reflect the mean well.

My region shows only a couple of days (out of 16) where the mean uppers fall below the seasonal average:

January at +2.6c above the average was a warm one, at least Feb looks likely to be closer to the climate average.

Look at the jet crossing the Atlantic:

D6 to D8>  D8-D16> 

Little chance of any heights building with the westerly jet powering through, so pretty much confirms the underlying atmospheric drivers that are preventing forcing, with the double whammy of the tPV being a monster, and keeping this winter under lock and key.

Does make you wonder whether that key to something cold and snowy UK-wide will be found at all this Winter. Otherwise, perhaps the models might find the key in Spring

(By then, might not be too shocking to see some of us going after warmer weather).

[carinthian]

Wow, I do not think I have ever seen a cyclonic circulation as huge as this one from ECM at 240t.

 C

[Mike Poole]

Holy schmoley!  ECM T240:

Looks like a NW'ly draw for some time after too, with cold air in there too:

Edit: beaten to it!!

This winter has been awful for cold, but so far, at least down south it hasn't been a storm fest, maybe a really unsettled stormy phase coming up for the country...

Edited January 31, 2020 by Mike Poole

[StingJet]

4 minutes ago, carinthian said:

Wow, I do not think I have ever seen a cyclonic circulation as huge as this one from ECM at 240t.

 C

That's a monster!! .. 935mb any closer to the UK with 1035mb over the Azores , would present a new angle on a UK Wide "White Out" ...............  an "Isobar White Out"  Pressure differential across the UK would be unprecedented

[Jeremy Shockey]

ECM 12z @t240

Scary !

Edited January 31, 2020 by Jeremy Shockey

[nick sussex]

A slightly less horrific run in terms of the PV blob from the ECM .

Note the weak height rises north of Svalbard and slightly more disruption to the PV .

If you’re looking for some PM air you need something to force the jet more south east near the UK .

Also that ridge east of Newfoundland. A bit more amplified upstream than the GFS.

I’m doing my best here ! We really are scratching around for something which might deliver even some PM air ! 

 

 

[stodge]

Once again, interesting to see the GFS 12Z OP taking the jet just along the Channel coast so the possibility of extended periods of PM air for northern Britain and snowfall for higher ground.

The ECM 12Z OP ends with a monster LP centred over (I think) western Norway - the MSLP would threaten the record for Norway which is 938 MB set in February 1907. Curiously, the record high MSLP for Norway is 1061 MB also set in 1907 (January). I have to say the winds associated with that monster would be country-wide and serious for the UK (fortunately the woodshed in the far SW should remain intact)

[cheeky_monkey]

2 hours ago, IDO said:

Don't bother with the GFS 12z FI, more of the same, just a different take, with the uppers weaker so mostly cold rain for England:

More likely than the better cold NW/W/ly flows, but too early for clarity, though something in that synoptic envelope looks highly probable.

looks like another potentially very cold Feb here..just like last year

[carinthian]

10 minutes ago, StingJet said:

That's a monster!! .. 935mb any closer to the UK with 1035mb over the Azores , would present a new angle on a UK Wide "White Out" ...............  an "Isobar White Out"  Pressure differential across the UK would be unprecedented

Just tried to trace back to the isobar line from Sussex , thousands of miles of equal cyclonic pressure. Got lost ! Yes, looking at the overview picture from ECM at day 10 , plenty of wintry showers packing into the NW with snow lying on hills with those winds , plenty of drifting. Hope it comes to fruition and then spread down to the Eastern Alps.

C

[feb1991blizzard]

8 minutes ago, Jeremy Shockey said:

ECM 12z @t240

Scary !

Its a stonker for 1000ft plus in North West England and Scotland - 20ft drifts covering houses likely.

[Purga]

Plus ça change, plus c'est la même chose

[Mr Frost]

Absolute wind/snow/kitchen sink mayhem here on the West coast of Scotland if these charts become reality!

Bring it on! 

 

Dream charts for an extreme weather enthusiast! (Like myself and many others) 

This would take the Winter from a 1/10 to at least 6/10.

Have a good weekend everyone! 

[Jordan S]

Persistent outbreaks of rain effecting western Scotland through this evening and overnight into tomorrow morning could give 20-30mm by morning this could turn wintry later in the morning as a colder feed of air moves southward. 

Hirlam..

Windy for many tomorrow especially through the central portion of England Wales, Ireland and Northern Ireland gusts to 40mph is likely in places 50-60mph is possible on hills in these areas as well as coastal spots. 

Icon..

Upper air temperatures for Monday and Tuesday next week are cold with sleet and snow to lower levels in Scotland, Northern England and northern Ireland likely in any showers that move through these areas with sleet and snow on hills elsewhere in any showers also a lengthier spell of snow for Scotland is possible from a low pressure system moving southeast on Monday into Tuesday with the potential for very strong wind gusts for Scotland too.

GEFS mean..

Ecmwf.. 

The following week still looks likely atm to be very unsettled with the potential for one or two intense low pressure systems crossing the Uk. 

Edited January 31, 2020 by jordan smith

[IDO]

ECM nice D10 (no surprise there), building a ridge/high to the west facilitating the better axis to get the colder uppers. No clear support from the mean ATM so maybe up to its normal tricks, though GFS has broached this type of possibility on previous runs, but has since moderated that colder flow. ECM mean and op:

 

Could not rule out just yet as the upstream Pacific high and embedded trough have diverged on the GFS and ECM:

GFS>  ECM> 

Less pent up heights in the Pacific high probably equates to more energy spilling along the corridor towards our sector, maybe giving us the slight mini-amplification needed. Certainly if it verifies it would be a noteworthy event.

[Kirkcaldy Weather]

5 hours ago, Man With Beard said:

And even better, your roof will get blown off so you won't even need to go outside to experience the blizzard. Mean winds verging on Cat 2 hurricane strength just a stones throw from Cornwall 6 hours earlier:

I have a bad feeling about the week after next - somewhere is going to get a mighty storm I feel. 

 

Will have to keep a close eye on the pressure values from the ensembles, lowest for here from GEFS 12z was 947 hpa   I agree with you though, with such an active jet stream and the cold air from the PV joining in stormy weather could easily crop up.

[Dangerous55019]

Hello everyone 

Its been a while since I've had chance to have a look at any charts or post anything, so I thought I'd dig out the CFS four week anomaly charts.

Well, what can I say?! If you fancy some Atlantic driven weather, with the threat of more winter storms, then the next three weeks should be right up your street! 

But I have to say that I've noticed that anomaly chart for the 21st to the 27th of February... A proper taste of spring? Or like last year Summer in winter? But either way that does look very settled... And after this train crash of a winter, I dare say that most of us will be looking for some nice spring warmth. 

As always this is the CFS, so please take these charts with a gritter load of salt.

[igloo]

37 minutes ago, Dangerous55019 said:

Hello everyone 

Its been a while since I've had chance to have a look at any charts or post anything, so I thought I'd dig out the CFS four week anomaly charts.

Well, what can I say?! If you fancy some Atlantic driven weather, with the threat of more winter storms, then the next three weeks should be right up your street! 

But I have to say that I've noticed that anomaly chart for the 21st to the 27th of February... A proper taste of spring? Or like last year Summer in winter? But either way that does look very settled... And after this train crash of a winter, I dare say that most of us will be looking for some nice spring warmth. 

As always this is the CFS, so please take these charts with a gritter load of salt.

the CFS weekly charts have been bang on all season to be fair. not once has it had any type of northern blocking or scandi highs and there is nothing bar the same showing for the  next 4 weeks.one thing I have notiched these weekly pressure charts either from the JMA or CFS or any other model are far more accurate than the day to day model runs 

[Tim Bland]