Cold hunt - models and chat

[offerman]

I think Dry snow is best because 

firstly you don't get wet while sledging jumping in it 

secondly, after all the fun of dry snow  as it gradually melts  it turns the wet snow enabling snowballs snowmen  so it's the best of both worlds .

 So these charts are looking good for at least white snow which is better than nothing and who knows if the cold can intensify maybe we will get some powder as well . 

 

 Much nicer looking chance at the moment then a couple of days ago on the GFS  and things could still improve further with longevity . 

[kold weather]

17 minutes ago, snowray said:

How on earth did Weymouth on the south coast get so much snow out of that? And yes, for those that moan about it, it's a NWly alright. Incredible stuff!

Its actually a SE airflow, quite a strong one at that! Hence why the boundary level remained cold despite what looks like debateable 850hpa temps.

As for 850hpa temps, they are a good guide but far from the be all and end all, just lasdt year in storm Emma 850hpa temps rose to about -2C but because the boundary level was so cold from the cold of the week, it still was powdery dry snow for the most part (the following day was wet snow).

Indeed March 2018 was the first time I've seen proper powdery snow. Living previously on the Thames Estuary most cold was moderated  to make it the wet variety. I'm sure Feb 2009 had powder, but I was unfortunately in Chichester back then.

[Snow Dayz]

34 minutes ago, s4lancia said:

Absolutely BB.The snowfall of a lifetime, 20ft drifts, tropical Weymouth was cut off for 3 days. The rain quickly turned to snow (not as forecast) on Saturday night and by lunchtime Sunday it was a winter wonderland.

As an 8 year old at the time, these are memories that will never fade. All that from this...

Relevant to those learning to understand that it isn't all about super strong HLB and/or about cold uppers taken in isolation.

I remember that caught the weather boys right out!

[PolarWarsaw]

Some promising looking charts this morning if it's snow you are after. If I lived somewhere, Buxton north then I would be excited about what next week may have in store. Those in the south are by no means out of the game, as we saw this week - I had no lying snow in the North West Midlands, but places in the SE and Oxfordshire had nice coverings - who stole my Cheshire gap snow?

Story of the winter though so far, don't look at macro details until within T24 - people who will undoubtedly view the GFS snow charts at T120 on today's 12z and then follow up with 'same rubbish all winter' or 'OMG that's big a slap of snow in my back garden next Wednesday at 9PM' need to take a step back. The charts can't nail this at T72 currently, let alone anything further. Low expectations, no disappointments. This island is one of the hardest in the entire northern hemisphere to get snow too and marginal snow, always provides our biggest falls.

The snowy nirvana has been at day 10 since about the middle of December and was also in the same place before high pressure took over in late November. 

My advice to you all - is look for the pattern, not the specifics. It makes it very frustrating to try and read a thread that turns into 15 pages of squabbling, when you have someone living on the south coast grabbing the Prozac screaming DOWNGRADE, DOWNGRADE like they are trying to land Apollo 13, whilst Simon from Sheffield is calling it a 'stonker' and stacking his shelves with bread for the impending snowy doomsday. 

Just 1 last point, for those of the negative vibe. Please can you not fill this thread with one liners, or snide comments about background signals. If you are of the view point that they have failed, then that's fair enough. But if you are so sure they have failed, you have no reason to keep mentioning it, or even bothering to come back to the thread to comment, do you? The lack of maturity and basic understanding of how the weather works by these said people is ruining what is, one of the best threads year on year on the internet. The downright bi-polar atmosphere makes it near impossible to have any sort of constructive discussion on the output. 

Come on guys, 

[danm]

7 minutes ago, kold weather said:

Its actually a SE airflow, quite a strong one at that! Hence why the boundary level remained cold despite what looks like debateable 850hpa temps.

As for 850hpa temps, they are a good guide but far from the be all and end all, just lasdt year in storm Emma 850hpa temps rose to about -2C but because the boundary level was so cold from the cold of the week, it still was powdery dry snow for the most part (the following day was wet snow).

Indeed March 2018 was the first time I've seen proper powdery snow. Living previously on the Thames Estuary most cold was moderated  to make it the wet variety. I'm sure Feb 2009 had powder, but I was unfortunately in Chichester back then.

Feb 2009 Thames streamer was powdery. Also don't forget Feb '91! 

[Johnp]

38 minutes ago, s4lancia said:

Absolutely BB.The snowfall of a lifetime, 20ft drifts, tropical Weymouth was cut off for 3 days. The rain quickly turned to snow (not as forecast) on Saturday night and by lunchtime Sunday it was a winter wonderland.

As an 8 year old at the time, these are memories that will never fade. All that from this...

Relevant to those learning to understand that it isn't all about super strong HLB and/or about cold uppers taken in isolation.

I presume that was before they built the M4 - nothing to repel the cold.

[frosty ground]

29 minutes ago, Jarrow Posh said:

Just for fun but P15 post 300z on the latest GFS run is one bitterly cold northerly,imagine the wind chill in that!

That's the stuff of polar lows

[Frosty.]

The GEFS 6z mean indicates it will be turning very cold during next week with some areas maxima struggling to reach freezing point..and plenty of opportunities for snow too!

[Methuselah]

16 minutes ago, Johnp said:

I presume that was before they built the M4 - nothing to repel the cold.

They always used to say 'North of The Thames', back in the olden days!

[Frosty.]

1 minute ago, Isleofwightsnowgal74 said:

Sounds great but what about the very far south coast? IoW to be exact? Thanks 

Low single digits celsius max

[Bruegelian]

To be fair, I believe that in March 2018, the southwest got the most snow in both cold spells. 

Edited January 24, 2019 by Bruegelian

[MP-R]

The Southwest is either all or nothing in these situations. We either get more than everyone else or hardly anything at all.

Channel coasts are most at risk of rain, and Devon/Cornwall.

[chris55]

At the range these sliders are being modelled the northern edge snow could literally be anywhere between the West Country and the Scottish Boarders.

if the pattern verified as being suggested many could see snow especially if we get a wrap around of the cold air in one of these lows. 

lots to be decided, a very complex forecasting task. 

Should keep us busy.

 

 

[Timmytour]

3 hours ago, chionomaniac said:

This chart is truly unbelievable. Off the scale cold into the heart of the USA. ( >-35C 850 hPa  temps)

No idea what chart I was looking at to get the idea from, but I tweeted on the 4th Jan to speculate whether Orlando, then at 27C, would see snow before the end of the month. Might not be that far off if that keeps heading south! 

[Steve C]

41 minutes ago, danm said:

Feb 2009 Thames streamer was powdery. Also don't forget Feb '91! 

Yes, wrong kind of snow etc, but he might be young...

Edited January 24, 2019 by Steve C

[stewfox]

2 hours ago, Weather of Mass Disruption said:

I love and really admire your input on here Chino, but have to admit I get seriously fed up with the yanks getting all the action every year. Definitely considering a relocation across the pond to Chicago, Wisconsin or anywhere else that has such unbelievable models that do actually verify! 

 

I think Donald Trump is going to need a little bit more 'rationale' for the move ? How's your IT skills ?

Anyway snow on the ground here now and GFS showing more options next week and we are still 4/5 weeks behind the Beast of the East that came last year in March.

 

 

[stewfox]

2 hours ago, swfc said:

Temps next week cold enough for snow but generally early on not the dry powdery snow.temps 850s ete don't look cold enough at sea level imo

If we ever get to the stage where we can choose the type of snow we prefer us soft southerners just north of the M4 can move to Weymouth. My location is still lamp post watching 4am.  

[NoTraction]

42 minutes ago, Frosty. said:

The GEFS 6z mean indicates it will be turning very cold during next week with some areas maxima struggling to reach freezing point..and plenty of opportunities for snow too!

However there have been many ups and downs on this Roller Coaster.... Lets hope its not the top of a medium sized loop only to invert upside down and back down we go.

It reminds me of the old Black Hole in Alton Towers where you couldn't see where you were going....... I would like to get off as I feel a bit sick, but you cant halfway round, we are all on it till the end!    HOLD ON TIGHT!!!!!

[Trom]

2 hours ago, Weather of Mass Disruption said:

I love and really admire your input on here Chino, but have to admit I get seriously fed up with the yanks getting all the action every year. Definitely considering a relocation across the pond to Chicago, Wisconsin or anywhere else that has such unbelievable models that do actually verify! 

My firm has an office in LaCrosse Wisconsin.  There's not a lot going on in most of Wisconsin other than corn and dairy.

The temps get so low that it rules out being outside for any period of time as any exposed skin starts to freeze.  I have been ice fishing on a frozen Mississippi.

Massive cold period about to hit the mid-West in the next few days. LaCrosse will be -20C in the day and closer to -30 at night by the weekend.

Edited January 24, 2019 by Trom

[February1978]

1 hour ago, s4lancia said:

Absolutely BB.The snowfall of a lifetime, 20ft drifts, tropical Weymouth was cut off for 3 days. The rain quickly turned to snow (not as forecast) on Saturday night and by lunchtime Sunday it was a winter wonderland.

As an 8 year old at the time, these are memories that will never fade. All that from this...

Relevant to those learning to understand that it isn't all about super strong HLB and/or about cold uppers taken in isolation.

As a 9-year-old in Taunton I remember this vividly too (see my moniker). Fence high snowdrifts, villages cut off for days - and it was completely unexpected / unforecast. I think it was just Devon, Somerset and Dorset - Cornwall missed out. Started snowing lunchtime Saturday, and over 18 inches by the morning. 

[Steve C]

2 hours ago, bluearmy said:

No idea if any pedants our there corrected the detail Kold but you need to multiply the slp by 0.87 (rather than 1) to give you the actual number to subtract/add from the heights 

Is the 0.87 factor just a good rule of thumb? I'm thinking pressure doesn't increase / decrease in a linear fashion through the depth of the atmosphere. Would an extreme (say) 950mb or 1050mb surface pressure test the 0.87 factor quoted?

Just interested, as I've wondered about this previously.

[Steve C]

2 hours ago, Ed Stone said:

Ah, but when you do get it it sure does deliver...Has all what fell in February 1978 melted yet!

Probably not in Greenland. 

Edited January 24, 2019 by Steve C

[kold weather]

34 minutes ago, Steve C said:

Yes, wrong kind of snow etc, but he might be young...

I was 2 at the point, so yeah to young to really remember anything, my first tentative snow memory comes from probably 95-96, or maybe 97-96, I'm not 100% certain!

Anyway won't be long before the 12z suite comes out. Don't get too hung up on the exact location of the LPs, they will shift around on these runs.

[bluearmy]

22 minutes ago, Steve C said:

Is the 0.87 factor just a good rule of thumb? I'm thinking pressure doesn't increase / decrease in a linear fashion through the depth of the atmosphere. Would an extreme (say) 950mb or 1050mb surface pressure test the 0.87 factor quoted?

Just interested, as I've wondered about this previously.

Steve m reckons it’s 0.8 - maybe work on 0.84 as a happy medium !!

[BLAST FROM THE PAST]

Ahhhh, if we get entrenched cold set up with the jet playing ball....we’ll be in the freezer for a long chunk of time with colder pulses and less cold...but surface temps could negate the less cold.  Now if that happens....

  It won’t be long , before we’re all there........ with Snow

Ps....don’t get hung up on massive HLB to start it all off

BFTP

Edited January 24, 2019 by BLAST FROM THE PAST