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Quantum
05 December 2014 16:40:11


 


Just to clarify do you mean:


(sea surface temp) - (850hpa temp)


So if sea surface temp is 15 deg C, and the 850hpa is -6, then it is (15) - (-6) = 15 + 6 = 21?


 


 


Originally Posted by: turbotubbs 


Yup. 


2023/2024 Snow days (approx 850hpa temp):
29/11 (-6), 30/11 (-6), 02/12 (-5), 03/12 (-5), 04/12 (-3), 16/01 (-3), 18/01 (-8), 08/02 (-5)

Total: 8 days with snow/sleet falling.

2022/2023 Snow days (approx 850hpa temp):

18/12 (-1), 06/03 (-6), 08/03 (-8), 09/03 (-6), 10/03 (-8), 11/03 (-5), 14/03 (-6)

Total: 7 days with snow/sleet falling.

2021/2022 Snow days (approx 850hpa temp):

26/11 (-5), 27/11 (-7), 28/11 (-6), 02/12 (-6), 06/01 (-5), 07/01 (-6), 06/02 (-5), 19/02 (-5), 24/02 (-7), 30/03 (-7), 31/03 (-8), 01/04 (-8)
Total: 12 days with snow/sleet falling.
Gooner
05 December 2014 16:41:28

http://www.wetterzentrale.de/pics/Rtavn1921.gif


Next Saturday looks bitter , plenty of snow showers about


http://www.wetterzentrale.de/pics/Rtavn1923.gif


http://www.wetterzentrale.de/pics/Rtavn19217.gif



Remember anything after T120 is really Just For Fun



Marcus
Banbury
North Oxfordshire
378 feet A S L


Polar Low
Gooner
05 December 2014 16:45:24

http://modeles.meteociel.fr/modeles/gfs/runs/2014120512/gfsnh-10-384.png?12


 


Some warming showing its hand


Remember anything after T120 is really Just For Fun



Marcus
Banbury
North Oxfordshire
378 feet A S L


doctormog
05 December 2014 16:46:27
Definitely a few interesting signs on the12z runs so far. I think I will refrain from much comment until I see a few more days of support. It does continue to the cool, mobile and unsettled picture albeit to more of a chilly extreme. Outlier or trendsetter?

It seems a long time since the last decent northerly here, so my fingers are crossed.
Quantum
05 December 2014 16:46:34


key moments on Gm


http://www.meteociel.fr/modeles/geme_cartes.php?&ech=126&mode=0&carte=1


Originally Posted by: Polar Low 


That 552 is never getting to greenland.


 


2023/2024 Snow days (approx 850hpa temp):
29/11 (-6), 30/11 (-6), 02/12 (-5), 03/12 (-5), 04/12 (-3), 16/01 (-3), 18/01 (-8), 08/02 (-5)

Total: 8 days with snow/sleet falling.

2022/2023 Snow days (approx 850hpa temp):

18/12 (-1), 06/03 (-6), 08/03 (-8), 09/03 (-6), 10/03 (-8), 11/03 (-5), 14/03 (-6)

Total: 7 days with snow/sleet falling.

2021/2022 Snow days (approx 850hpa temp):

26/11 (-5), 27/11 (-7), 28/11 (-6), 02/12 (-6), 06/01 (-5), 07/01 (-6), 06/02 (-5), 19/02 (-5), 24/02 (-7), 30/03 (-7), 31/03 (-8), 01/04 (-8)
Total: 12 days with snow/sleet falling.
Gooner
05 December 2014 16:47:31

http://www.wetterzentrale.de/pics/Rtavn2161.gif


http://www.wetterzentrale.de/pics/Rtavn21617.gif


Be a shock to the system


Remember anything after T120 is really Just For Fun



Marcus
Banbury
North Oxfordshire
378 feet A S L


Matty H
  • Matty H
  • Advanced Member Topic Starter
05 December 2014 16:47:46


Will certainly feel cold in the wind, but would also be mostly dry away from exposed coasts. Typical boring northerly for most of England. Better for other areas of course. 


Russwirral
05 December 2014 16:49:03

Once that northerly hits the charts start to resemble an ensemble mean chart, lots of spacing in the isobars, and eveything looking less severe.


 


Netweather GFS Image


 


I think its more to do with the variables associated with the cold shot and the charts are struggling to make sense of it.  It looks like GFS falls back to old reliable ie - inject a little more energy into the atlantic


 


Something tells me this wants to dive south and draw in an easterly.  But it doesnt quite get there...


doctormog
05 December 2014 16:54:23


Once that northerly hits the charts start to resemble an ensemble mean chart, lots of spacing in the isobars, and eveything looking less severe.


 


 


 


I think its more to do with the variables associated with the cold shot and the charts are struggling to make sense of it.  It looks like GFS falls back to old reliable ie - inject a little more energy into the atlantic.


Originally Posted by: Russwirral 


Is that not the time point where the GFS enters its lower resolution section of charts?


David M Porter
05 December 2014 16:56:34


 


At face value its more than enough. For those that are interested, here are some golden lake effect rules. Take the upper (850hpa) temp and subtract from the sea surface temp. In general the bench marks apply:


Note lake effect can be rain if its not cold enough!


13C: Light snow flurries possible


15C: Scattered light snow showers, isolated moderate snow showers.


17C: Moderate snow showers, occasionally frequent, isolated heavy snow showers.


19C: Moderate or heavy snow showers, often frequent


21C: Heavy snow showers often merging to persistent heavy snow. Isolated thunderstorms.


23C: Very heavy snow, thunderstorms likely. 


 


That chart is about 17C. 


Originally Posted by: Quantum 


Thunderstorms with snow? I believe that thunder can indeed occur with snow but I don't recall experience it in my lifetime.


Lenzie, Glasgow

"Let us not take ourselves too seriously. None of us has a monopoly on wisdom, and we must always be ready to listen and respect other points of view."- Queen Elizabeth II 1926-2022
snowmad
05 December 2014 16:58:32

Its good to see the number of members on site is over the 200 mark. That normally means somethings afoot and interest levels are high with the current model output

idj20
05 December 2014 16:58:50

Oh, it's suddenly come alive in here now, but I can see why. However, the thing with northerlies is that I tend to be on the lee sheltered end of it with the best of the sunshine - not that it is a bad thing in itself! Assuming it does come off in the first place as it is a good week away in forecasting terms. 
 Also, I don't want to be a party pooper but don't forget there is a bit of rough and tumble to put up with beforehand in the form of widespread and locally severe westerly-type gales across the UK on Wednesday and into Thursday. That part is pretty much nailed on at this point.

Wonder what the mighty ECM will come up with in a couple of hours time.


Folkestone Harbour. 
Solar Cycles
05 December 2014 16:58:52

I that  verifies  then all eyes will be on any polar lows forming in the unstable airflow, a long way out but something that's been in my thoughts over that last few days. What we need thereafter is heights over NE Canada extending into Greenland, a possible outcome but at this stage one of many solutions.

Russwirral
05 December 2014 16:59:16


 


Thunderstorms with snow? I believe that thunder can indeed occur with snow but I don't recall experience it in my lifetime.


Originally Posted by: David M Porter 


 


happened during the lake effect snow in the US the other week.  Ive heard it happening in manchester back around 2002/3 where we had a couple of snow inducing northwesterly's.  The convective streamers were quite powerful back then.


 


 


 


 


Polar Low
05 December 2014 17:02:04

Those showers would be drifting inland places like EA and N/E dont forget about the axis of the chart that Marcus posted.


http://www.meteociel.fr/modeles/gfs/royaume-uni/precipitations/192h.htm


 



 


Will certainly feel cold in the wind, but would also be mostly dry away from exposed coasts. Typical boring northerly for most of England. Better for other areas of course. 


Originally Posted by: Matty H 

Gooner
05 December 2014 17:03:27


 


 


happened during the lake effect snow in the US the other week.  Ive heard it happening in manchester back around 2002/3 where we had a couple of snow inducing northwesterly's.  The convective streamers were quite powerful back then.


 


 


 


Originally Posted by: Russwirral 


I remember the Thunder snow event here several years back, we had a few inches in a very short space of time


Remember anything after T120 is really Just For Fun



Marcus
Banbury
North Oxfordshire
378 feet A S L


Chiltern Blizzard
05 December 2014 17:04:00


 


Thunderstorms with snow? I believe that thunder can indeed occur with snow but I don't recall experience it in my lifetime.


Originally Posted by: David M Porter 


 


The "thundersnow" event of January 2004 was quite widespread across England... take it you missed out IYBY.


Rendlesham, Suffolk 20m asl
turbotubbs
05 December 2014 17:05:04


 


 


happened during the lake effect snow in the US the other week.  Ive heard it happening in manchester back around 2002/3 where we had a couple of snow inducing northwesterly's.  The convective streamers were quite powerful back then.


 


 


 


 


Originally Posted by: Russwirral 

Happened in the UK in 2004 too. Notably heavy, rapid snowall. Caused chaos in Norwich (cars gridlocked for hours)

idj20
05 December 2014 17:05:54


 


Thunderstorms with snow? I believe that thunder can indeed occur with snow but I don't recall experience it in my lifetime.


Originally Posted by: David M Porter 



I've experienced that here at Kent once, in the early morning of 11th Feb '10 when I saw huge flashes of lightning and heard loud rumblings during a blizzard. To get the heavy snow was one thing but to have the thunder to go with it was another thing! But it was all part of an active Channel Streamer/Kent Clipper coming in from the Hook Of Holland. It gave me 9 inches of laying snow in the end.


Folkestone Harbour. 
Gooner
05 December 2014 17:06:57


 


 


The "thundersnow" event of January 2004 was quite widespread across England... take it you missed out IYBY.


Originally Posted by: Chiltern Blizzard 


Blimey was it really 10 years ago , seems like yesterday and it was a cracker here ....no pun intended


Remember anything after T120 is really Just For Fun



Marcus
Banbury
North Oxfordshire
378 feet A S L


LA2B MeridFlowEuro09
05 December 2014 17:11:58

Seen a Cold Northerly GFS 12z, and the UKMO 12z Meteociel is More Cyclonic with intensity and Depth of Cold very Similar (p.m. 9th, more especially 10th to 11th, and it would drag in A Arctic plunge if we follow GFS, the UKMO showing it less North flow for Thursday.


I will want tiger to next Tuesday and hope that within following 48-72 hours the GFS and ECMWF and UKMO keep up this evolution.


Take care and do not turn up the H Y P E, IF is good but the B U T is something else we know this a lot.


Pacific, USA and Atlanic Big Weather Picture is trending very nice at the moment as has been since 22nd November, and the appearance of Antarctic Noctilucent Clouds plus the Stratoshoeric warming in the Northern Hemisphere if all goes to plan then very good things are getting on fine, Russia North, Central NE Siberia and Arctic High is reflecting it well, so are PV and Cold Arctic Lows NE and North Pacific but more greatly Northeast Canada through Greenland Iceland as well- the North and East USA High and Links to large Central Mid to W N Atlantic High that affects well to our SW to Azores WNW as well, NW Corner Cold Arctic PV Low track o North and Mid to far NE Atlantic SW Central Norwegian Sea and West to North UK via Iceland main Crossing to Norwegian Sea all this looks set to continue and having Wet and Windy Low Pressure heading regularly across to SW USA South USA then quickly head to NE USA Corner and dragging warm air to its SW and South SE in USA all this is well and truly great weather set up.


And Typhoon Cat 5 Hagupan 185 mph mean winds with 225 mph gusts is slow moving and expected to cross East and Central Phillipines and track is sa


e as TS Haiyaan the Filipino's are calling this one Ruby and Haiyaan for them had a different name.


A Large Long Cold Front is in the Western NW Atlantic and right Upto SE Greenland Sea toward SW Iceland that is Sunday and Monday's spell of wintry showers and sunshine spells, with a frosty Sunday/ Monday night.


Climate is warming up, Scotland and N Ireland and North England still often gets some Winter frost, ice and snow, November to March, but the SE and South UK including S Central England and Wales, together with the West and North through the year, they sometimes get more rain than London and S SE England, where some longer dry fine spells without much heavy rain is seen every year.

The North Atlantic Sea often gets some much Colder Wintry conditions from November to March Months, and Mild SW and South winds tend to be more frequent over the East and SE of North Atlantic Sea, as the Azores High tends to stay in charge. 

With this warmth and heat, the Central and South UK has become mostly free of snow and frost.
Polar Low
05 December 2014 17:15:35

1987 springs to mind for us folk in EA


It has its own Written history most folk around here talk about it today who are not even weather nuts like me


http://en.wikipedia.org/wiki/January_1987_Southeast_England_snowfall



 


 


 


 


 


 



 


I remember the Thunder snow event here several years back, we had a few inches in a very short space of time


Originally Posted by: Gooner 

White Meadows
05 December 2014 17:21:20

Towards the end of the 12z you can see high pressure exerting itself at higher latitudes to our North West, Eastern Canada across to Greenland. A sign the PV is migrating east / reducing in strength.


http://jpwxcharts.blogspot.co.uk/2014/02/blog-post.html



I have a hunch we'll be looking north and north east, rather than at standard easterly continental air later this month.

Stormchaser
05 December 2014 17:22:43

Well this is a bit exciting... another huge adjustment SW in the U.S. low on the GFS 12z op run changes the game significantly, with the mid-Atlantic ridge able to build up towards Greenland rather than being flattened and sent toppling toward the UK.


I've used the Meteociel charts for easier comparison with the UKMO and GEM charts on the second row:


Modele UKMO - Carte prévisions   Modele UKMO - Carte prévisions


Modele UKMO - Carte prévisions   


 


UKMO is not far off the GFS solution but the shortwave development on the western flank of the main trough is a lot more pronounced. On the other hand, the U.S. low is even further southwest than GFS has it.


GEM still has the low in the sort of location that GFS had it on the 00z op run.


 


The GFS run evolves into by far the most amplified solution seen so far in terms of the Atlantic pattern:



Cold enough for snow showers streaming down the eastern half of England and across most of Scotland.


As usual, the pattern suddenly starts flattening once into lower-res (+192 onward), but that doesn't stop the far more amplified setup beforehand from increasing the strength of the wave breaking into the stratosphere (the mid-Atlantic ridge nudging into Greenland is a real bonus), producing the strongest warming yet and continuing the trend of the day so far:


Netweather GFS Image


You can even see the strat. vortex starting to come apart as a result.


Remarkable developments! Now, will the tendency to progress things along a bit too quickly be countered by this trend towards stronger warming? It now starts off at days 9-10 so getting close to higher-res, amazingly enough. The really strong stuff takes until day 14, though, so best not to get too carried away...


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