Model discussion: Hunt for cold - into mid-January

[matt111]

4 minutes ago, Pixel said:

Ok since it's quiet and I've been sitting on this question for years..

A lot of knowledgable folk on here talk about "heights" and "low heights" ... is this a very high pressure system and lower high pressure system or are the low heights a low pressure system?

Please, in simple terms put me out of my misery - Thanks in advance 

 

 

I generally only read this thread rather than posting in here but from what I gather heights just means high pressure and low heights is low pressure

Edited January 12, 2022 by matt111

[damianslaw]

2 minutes ago, Pixel said:

Ok since it's quiet and I've been sitting on this question for years..

A lot of knowledgable folk on here talk about "heights" and "low heights" ... is this a very high pressure system and lower high pressure system or are the low heights a low pressure system?

Please, in simple terms put me out of my misery - Thanks in advance 

 

 

I tend to use Heights when describe higher pressure/ ridges.. low heights to describe lower pressure. 

[Malcolm Edwards]

Oh well no doubt it will be full on weather porn in the morning as the models once again will tease. 

[damianslaw]

2 minutes ago, Malcolm Edwards said:

Oh well no doubt it will be full on weather porn in the morning as the models once again will tease. 

I fully expect the GFS to keep showing northerly plunges at times in many runs.. but the ECM to stay much more reserved.. for the time being. May see a northerly feed later in the month though. 

[Cold Winter Night]

To be honest, I don't see fundamental differences on the GFS 18z, compared to earlier runs.

It's still a pretty good run overall.

No, indeed this run doesn't give us one of those shiny Northerlies earlier on, but the general theme of late is still there:
Leaving part of the tPV in the Eastern Hemisphere.
Highly meridional pattern, driving the American trough far South.
Continued amplified Atlantic, sometimes attempting to get even further North.
Lowering heights in Europe in FI.

And a succesful Northerly could just as well be back on the 0z, or the 6z or the 12z. Because it's still represented in GEFS.

[IanT]

1 hour ago, Don said:

If that happens, winter will be a goner but great for those wanting an early spring (which isn't me!!)

It’s only the second week of January. Surely a little early for “winter is over”, especially with some powerful features in play elsewhere on our side of the northern hemisphere..!?

[Mapantz]

 

10 minutes ago, Pixel said:

Ok since it's quiet and I've been sitting on this question for years..

A lot of knowledgable folk on here talk about "heights" and "low heights" ... is this a very high pressure system and lower high pressure system or are the low heights a low pressure system?

Please, in simple terms put me out of my misery - Thanks in advance 

I think there can be some confusion when using the word "heights" 

Generally, geopotential heights are often referred to as heights.  Low heights are usually in cold air masses, and high heights in warmer ones.

[Cold Winter Night]

11 minutes ago, Pixel said:

Ok since it's quiet and I've been sitting on this question for years..

A lot of knowledgable folk on here talk about "heights" and "low heights" ... is this a very high pressure system and lower high pressure system or are the low heights a low pressure system?

Please, in simple terms put me out of my misery - Thanks in advance 

 

 

A chart like the one above shows two variables:

1) The surface pressure, expressed in hPa and made visible with the white isobars.
2) The height of the level where the air pressure is equal to 500 hPa. This is expressed in decameters (dam) and made visible with the colours. See the legend at the bottom of the chart.

The last variable is what we refer to when talking about "heights".
Higher values (higher heights) mean that the 500hPa level is found higher up, and therefore there is 'more air' below it, it's a thicker layer of air (usually warmer too). The more yellow and orange, the higher the heights.
Lower heights are represented by the blues and purples. In those places the layer of air is thinner (usually colder) and therefore the 500 hPa level is already found at a lower height.

On average this 500 hPa surface is higher as you go further South towards the equator (obvious on charts), because warmer air has a lower density and takes up more space than cold, dense air.

The tricky thing is that often low pressure systems at the surface are associated with a "low height" of the 500hPa level, but not always.
And high surface pressure is often associated with a "high height" of the 500hPa level, but not always.

If they go together, they are more powerful. If they don't they are weaker features.
For example, a "wedge" is an area of higher surface pressure that does not have a really high 500 hPa level. It is weaker than a real High, because it is not backed up by that thick layer of air, so to speak.

Hope this helps!

 

[Pixel]

29 minutes ago, Mapantz said:

 

I think there can be some confusion when using the word "heights" 

Generally, geopotential heights are often referred to as heights.  Low heights are usually in cold air masses, and high heights in warmer ones.

LOL.. oh no.. looks like I'm going back into hibernation till next year then

Cyclonic or Anticyclonic is as far as i understand.. thing is I've never seen a forecaster on TV mention 'heights' hence my confusion with the word - especially after searching this forum and internet.  How are us mere mortals suppose to understand terminology if only a few in the same room the know what they mean?

My brother in law is a theoretical particle physicist and has to speak publicly (what they call 'colloquials' or presentations) to explain, in the simplest terms, what he is doing so as to educate everyone present to further science research - alas I still don't understand the 'Lattice theory' but we try and we do have fun.

 

edit - cheers for the help everyone.. i've a lot to learn.. which is good.. (-: 

Edited January 13, 2022 by Pixel
spwellin

[feb1991blizzard]

the GEFS are an absolute snorter in FI, a majority cold cluster, but problem is how reliable have they been lately!

[sorepaw1]

I'd like to say there is some really good posts at the moment I'm finding them very useful and outstanding some of them

Well done you guy's 

It's quality at It's best 

Thank you. 

[feb1991blizzard]

5 hours ago, feb1991blizzard said:

the GEFS are an absolute snorter in FI, a majority cold cluster, but problem is how reliable have they been lately!

0z suite not as good - a degree or so warmer.

[KTtom]

Ecm 120 really highlighting the issue imho, to get a substantual block via an Atlantic ridge we need the PV attacked from both sides. Gfs control yesterday demonstated this nicely with an Arctic high linking up with the Atlanric ridge. Without heights nedging south from the Arctic, our (think it' ll feel like a family member by end of Jan) hasnt really got a chance of much northerly progress.. regarding gfs ens, pretty poor, just one sad straddler showing a northerly next week, the mean straddling average right until the end of the run with the op very much on the milder side but its all to do with the positioning of the high.

 

Edited January 13, 2022 by KTtom

[supernova]

Another phantom northerly from GFS finally evaporates as we near the crux, sadly. High and dry, in more ways than one, from all models thus far. We are forced to look further out and hope the fiercely active PV rips itself in half or the weather gods throw us another glimmer of hope beyond the foreseeable. Thank goodness the models can reveal unexpected results miraculously quickly in this game, though not for a day or three based on the output this morning. Long way to go yet this winter and background factors remain favourable. Anyway, I always prefer Feb for a good dumping if we get nowt before Xmas (and I don’t mean fly-tipping - too much of that round here in the rurals as it is!).

Edited January 13, 2022 by supernova

[Summerstorm]

ECM better than GFS +168 and very similar to GEM too won't get there this time but maybe third time is the charm this time around  

Wouldn't take much of an adjustment for a decent toppler but a true Greenland high is out of the question for now based on current output. Maybe this will change as the models have been volatile although it's at odds. 

GFS again sniffing out a move to Scandi out in Day 13-15 over the last few runs will have to see whether that trend continues. 

Anyway end of ECM seems to have promise with nice forcing on the PV and more of it draining out of Canada. However we probably won't convert it. Anyway I'm out now until the 6z runs have a good morning everyone. 

Edited January 13, 2022 by Summerstorm

[That ECM]

T240 hoping ecm has the nhp broadly correct as gfs looks a lot less favourable moving forward. It’s still a watching brief for now. 

[DavidS]

High pressure forever on the 00z suites  this morning. The GFS has us under high pressure for the entire run, with only deep FI really suggesting it might want to e on the move.

 

[mb018538]

6 hours ago, Pixel said:

LOL.. oh no.. looks like I'm going back into hibernation till next year then

Cyclonic or Anticyclonic is as far as i understand.. thing is I've never seen a forecaster on TV mention 'heights' hence my confusion with the word - especially after searching this forum and internet.  How are us mere mortals suppose to understand terminology if only a few in the same room the know what they mean?

My brother in law is a theoretical particle physicist and has to speak publicly (what they call 'colloquials' or presentations) to explain, in the simplest terms, what he is doing so as to educate everyone present to further science research - alas I still don't understand the 'Lattice theory' but we try and we do have fun.

 

edit - cheers for the help everyone.. i've a lot to learn.. which is good.. (-: 

This is a great place to learn!

We often use these NOAA 500mb ('heights') plots below on this page too. Gives a nice snapshot of the upper flow around the USA/Atlantic/UK area. The green lines show where the ridges and troughs are at 500mb - as you can see there is a big bulge in these very close to the UK. The red hatched lines and numbers shows the 500mb anomaly relative to the average....and as there are lots of red lines and the ridge is up to 270dm above average, it's showing a very intense ridge at 500mb. With strong high pressure at the surface too, we end up with high pressure that isn't really shifting. This is when we can say high pressure extends from the surface up through the atmosphere, which makes it far more robust. With such a strong ridge, it's usually balanced out with a deep trough on the other side....this currently sits across the NE of the USA/Canada, where there is going to be punishing cold weather for the next 7-10 days.

[JOPRO]

Still think we have a good shout going forward with this high pressure cell moving over us and out to our west, we have far better a far better chance than low pressure barrelling into us from the west/s.west ala 2013/14.

[mb018538]

Barely a drop of rain in sight in the next 10 days for the vast majority of the UK. Only exception being the NW of Scotland as fronts drape across this corner.

ECM clusters day 10-15 this morning show high pressure staying close by. No signs of a low pressure fest at the moment. GFS pressure ensembles singing from the same page. A boring outlook for many.

[Nick2373]

It’s like ground hog day in here in the mornings, same posters posting the same. I’ve got the winter bingo going 

1. winter is over 

2. more runs

3. Chucking the towel in

4. PV is to strong.

really giving the current performance of the models I wouldn’t pay attention to anything past three days at the minute. 
 

anyways current outlook Dry sunny spells now and again with possibly hints of a pattern change from around the 21st perhaps.

Edited January 13, 2022 by Blessed Weather
Unnecessary comment removed.

[booferking]

The search for cold and snow goes on the models have deteriorated again from last night in the fi,  some mention well atleast it's dry and cold with frost well 2 nights running and 6-8 degrees here both nights, give me a good old exciting storm any day of the week.

[IDO]

The NH is in a quasi-blocked static state where the blocks have left the UK close to a HP. There is plenty of cold to mid-lats but the three waves send the cold too far from our little island:

D8-16 T850s> 

It is amazing to see the next 16 days how each wave of cold circulating the vortices managing to miss the UK! This underlying pattern dictates that result so to be expected and Jan looks tough for any snow as things stand. Can this cycle continue in February and finish winter or is a sea-change coming? 

[minus10]

Yes amazing that there is so much hp now for all of Jan it seems

Also it has been a crystal clear night...no fog...and the temp has barely got down to zero. Quite amazing really for a long night in January. Are well.... least the sunshine is nice..

[That ECM]

37 minutes ago, sheikhy said:

There is a reason why ive hardly been commenting and posting these ridiculous charts from gfs!!gfs is crap its simple lol!!it cant even get anything right at day 4 lads!We are in huuuuge trouble as things stand guys if snow is what your looking for!!this is fast becoming a winter to forget!a lot of posters were saying the same thing a few weeks ago but the reply was we only in late december!!well you cant be sayin that anymore with us being in the middle of january now!fast running out of time!!nothing suggests to me that we are gona see anything in terms of snow for the forseeable!!!dont even bother falling for these amplifications after 144 hours cos they have not become reality!!!one thing that looks certain is we are in for an abundance of dry boring weather!!!i will take the dry but lack of snow nah mate!!!!things can change of course and i hope they do but its not looking good at all!!

Can’t get anything right at 4 days? I understand the frustration but I would say it’s not that far off.