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doctormog
10 February 2015 18:33:10


No chart available for the selected hour. Many charts start at 3 hours ahead, so if you have 0 hours selected try stepping forward or selecting a later hour.


A dip in temps towards 14th and then down again to the 17th , looks like a dive in temps towards months end

Originally Posted by: Gooner 


That could very well be an indicator of more unsettled conditions rather than colder ones at 2m level. The current high t850s are associated with anticyclonic conditions which, while mild in some places, could be equally as chilly in others at surface/2m level.


David M Porter
10 February 2015 18:45:25


Honestly that scandi thing doesn't interest me in the slightest, it won't produce anything of note away from the hills unless a warm front stalls and even then its unlikely. Anyway 12z is pretty awesome for the longer range. Look at this:



HP established across the UK; excellent  Notice the secondary ridge south of Newfoundland.


 



Attack by trough to the north, Primary high declines to the SE


 


 



First pulse from the secondary high, notice how the centre is now further to the west and the north than the original primary. This is now the new primary, with the secondary forming once again south of newfoundland.



2nd attack causes primary to decline to the SE, notice this time we almost get a northerly.



Secondary high pulses from the south, notice the centre is once again even further west.


 


By this iterative procedure, the HP will move further and further west and north, it is something I have observed countless times, eventually it gets to a stable location in greenland provided there is no pattern change. Also this is another reason why I do not want this bloody scandi high, this is a great situation to be in, it doesn't always get to greenland but it has a decent chance, I want to at least attempt this journey, not have a bloody scandi high preventing it before it has even begun. 


All I can say is...



 


 


Originally Posted by: Quantum 


I admire your optimism Q! Let's hope that something good comes of it eventually.


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
JACKO4EVER
10 February 2015 19:01:19
I couldn't imagine anything worse than a half arsed attempt at winter from the North during March. I for one am hoping that we will start moving into spring soon with sunshine that warms your face and lightens your heart.
People looking at 300 hour charts for hints of wintryness- it can wait another 300 bloody days for me. 3c here today, misty and cool. Crap.
The Beast from the East
10 February 2015 19:08:15

So we do get a scandi high, but its rather pointless with the northern jet as it is. GEFS dont show much of interest.


"We have some alternative facts for you"
Kelly-Ann Conway - special adviser to the President
KevBrads1
10 February 2015 19:13:29

 3c here today, misty and cool. Crap.

Originally Posted by: JACKO4EVER 


At least it was dry.....


 


 


 


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doctormog
10 February 2015 19:15:25


So we do get a scandi high, but its rather pointless with the northern jet as it is. GEFS dont show much of interest.


Originally Posted by: The Beast from the East 


You think? I rather like the snow chances on the 14th 


http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&lat=57.2&lon=-2.3 


Quantum
10 February 2015 20:10:34


 


Q, I have chosen this paragraph to comment. You have selected a chart for +384 and then said it might happen so long as there is no pattern change.


It is surely the model output equivalent of tipping a cup of water into a river and then expecting to recover the same water five miles downstream.


It is an interesting explanation of what might happen, but has very little chance of actually occurring like that. Time will of course tell.


Originally Posted by: nsrobins 


I get your point, but the iterative procedure actually begins at 192hr, and on the 6Z ensembles there was incredible support for HP domination at ~300hrs, some ensembles will, I'm sure, only need two cycles to get the greenie, others will take four (the OP actually doesn't manage it in the 384hr time period), I think the point to highlight here is that there is very good support for arguably the most common method 'journey' to a greenland high. And if I'm honest given that all the ensembles at 300hr seem to be onboard I would be suprised if the journey is never attempted, just like I was surprised by the incoming trough. I don't want people to think I am cold ramping though or seeing potential where there is none, I think there is potential here. In terms of verification of a cold spell I'd say 80% conservative that the 'journey' is attempted, perhaps 50% of journeys end up in at least a notable fleeting cold spell, so that's 40% chance conservative of at least some cold spell in the last week of February.    


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.
Quantum
10 February 2015 20:19:42

The iterative method is also showing on the ECM although we only get to see one cycle. 



Note how the secondary high becomes the new primary and ends up being further west in the last image than the original primary was in the first. The new secondary high is getting ready to pulse up even further west. 


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
10 February 2015 20:28:57

No chart available for the selected hour. Many charts start at 3 hours ahead, so if you have 0 hours selected try stepping forward or selecting a later hour.


Quite a few runs going for cold near the end .............correct set this time


Remember anything after T120 is really Just For Fun



Marcus
Banbury
North Oxfordshire
378 feet A S L


Stormchaser
10 February 2015 20:55:59

Hmmn.


With a split jet in the 4-5 day range I have opened one eye to it after many days of slumber. The models often struggle to capture how strong the southern arm of the jet - undercutting the high which in this case looks to be over Scandinavia - is, as GFS has done a good job of showing us so far today (LP was NW of the UK on the 00z, now heads to the south!).


Unfortunately atmospheric momentum is receiving a boost this week that was not foreseen at the longer range - hence the idea of HP pulling back west again before too long had to be thrown into the trash, at which point I decided to use the uninteresting outlook to take a much needed break.


 


Beyond the coming 7 days, the signal for the background drivers to start favouring a substantial drop off in momentum, with HP encouraged toward Greenland again, remains - it seems to have just been put back a week rather than being scrapped altogether.


GFS has been hinting at this potential on a few recent runs, but it will take something special for me to start raising eyebrows much. It would be handy for keeping the CET down of course innocent


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Keep Calm and Forecast On
llamedos
10 February 2015 21:38:04


 


I get your point, but the iterative procedure actually begins at 192hr, and on the 6Z ensembles there was incredible support for HP domination at ~300hrs, some ensembles will, I'm sure, only need two cycles to get the greenie, others will take four (the OP actually doesn't manage it in the 384hr time period), I think the point to highlight here is that there is very good support for arguably the most common method 'journey' to a greenland high. And if I'm honest given that all the ensembles at 300hr seem to be onboard I would be suprised if the journey is never attempted, just like I was surprised by the incoming trough. I don't want people to think I am cold ramping though or seeing potential where there is none, I think there is potential here. In terms of verification of a cold spell I'd say 80% conservative that the 'journey' is attempted, perhaps 50% of journeys end up in at least a notable fleeting cold spell, so that's 40% chance conservative of at least some cold spell in the last week of February.    


Originally Posted by: Quantum 

I admire how you always support your view of current output however I have some doubt about how you arrive at a "40% chance conservative of at least some cold spell in the last week of February" given your uncertain starting assumptions "I'd say 80%" and " perhaps 50%" as you've posted above. All sounds a bit "if this" an "also that" then possibly..........sounds a bit shaky to me, but I'm always open minded and therefore keen to learn how the mathematics worked for you to arrive at your conclusion. 


"Life with the Lions"

TWO Moderator
Quantum
10 February 2015 23:07:03

The 18Z ends with a northerly



Again we see the same pattern of a low crippling a primary high only to pump up a secondary high further to the west. This only took two cycles (between 192 and 384) to produce a bitter northerly. Part of what makes me optimistic here is that its such a common method to make Greenland highs, in fact I think it might even be the easiest way to do it, though the scandi+slicer low method must come close.


 


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.
Andy Woodcock
10 February 2015 23:34:45

Tonight's models are clear and consistent, no chance of wintry weather until at least late February, that's not being pessimistic just realistic.


I therefore in time honoured fashion declare....


'Winter Is Over'


Andy


Andy Woodcock
Penrith
Cumbria

Altitude 535 feet

"Why are the British so worried about climate change? Any change to their climate can only be an improvement" John Daley 2001
GIBBY
11 February 2015 08:38:25

HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST POWERFUL WEATHER COMPUTERS

THE CURRENT GENERAL SITUATION
High pressure will move away slowly East across Europe leaving a slack but slowly freshening Southerly flow across the UK later tomorrow.

http://www.wetterzen...cs/Rtavn001.gif

MODELS-2 WEEK HEADLINE Dry at first and possibly again later with an unsettled period from late this week and into the beginning of next.

THE GFS JET STREAM ENSEMBLE FORECAST The Jet Stream Ensemble Forecast shows the flow blowing in an Eastward motion to the North of the UK. This is then disrupted as the flow is diverted South over the UK late this week with a sine wave pattern in the flow occurring for a time before it slowly reverts to a position north of the UK by the end of the run.

 http://www.theweatheroutlook.com/twodata/datukgfshires.aspx?display=jetstream&model=gfs

GFS OPERATIONAL The GFS operational today shows the current High pressure slipping away East in the wake of Low pressure moving in from the West and slipping away SE towards the weekend filling steadily. The legacy will be a weak trough with further pulses of rain for a time into next week before High pressure gradually reasserts itself across the UK with a lot of dry weather through week 2 with amounts of cloud again becoming the biggest issue in otherwise fine and benign weather  and temperatures hovering just a fraction either side of average.

http://www.wetterzen...s/Rtavn1441.gif

http://www.wetterzen...s/Rtavn3841.gif
 
THE GFS CONTROL  The GFS control run is largely similar with windy conditions in the North and NE at times through the period with alternating mild and rather colder conditions. In the South the more benign conditions explained within the operational text will be most likely under High pressure which will remain close by to the South or SW.

THE GFS CLUSTERS The GFS Clusters today show unanimous support for High pressure to lie to the SW of the UK in two weeks time with just variations on the proximity of that High dependent in conditions experienced. most keep it far enough away to allow a NW or West flow with occasional rain especially but not exclusiveley in the North.

http://www.weatheron...=0&WMO=&PERIOD=

UKMO UKMO this morning shows Low pressure becoming much more influential later in the weekend and start to next week with the end of week rain and showers of the weekend replaced by further rain and a strong and cool WNW showery airflow to start next week before a weak ridge approaches the UK from the West towards midweek.

http://www.wetterzen...cs/Rukm1441.gif

THE FAX CHARTS The Fax Charts this morning indicate a much more unstable period to come as Low pressure and troughs affect the UK from Friday with the pressure pattern remaining complex with further approaching Atlantic fronts likely to affect the UK from Day 5

http://www.weatherch...momslp.htm#t120.

GEM GEM shows a quick return to High pressure building across the UK towards the middle of next week replacing the unsettled interlude of the weekend and start to the week/ Then apart from a few showers near Southern England for a time the weather should stay largely dry and quiet for most.

http://www.wetterzen...cs/Rgem2401.gif

NAVGEM NAVGEM shows the unsettled period of the weekend and start to next week give way to drier and brighter weather as High pressure builds to the South. This sets up a mild but strong SW flow across the UK by the end of next week with occasional rain in the North.

http://www.wetterzen...cs/Rnvg1681.gif.

ECM ECM shows an evolution quite close to that of NAVGEM moving forward to bring High pressure close to the South and then West of the UK with only occasional interventions of fronts affecting the far North at time with quieter and more settled conditions in average temperatures across the South.

 http://www.wetterzen...cs/Recm2401.gif

ECM 10 DAY MEAN The 10 Day Mean this morning maintains a mid Atlantic High likely in 10 days time with a ridge extending East towards Southern Britain while Low pressure to the North keeps more changeable conditions under Westerly breezes in the North.

http://www.wetterzen...cs/Reem2401.gif

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The long term trend continues to show an unsettled period before High pressure reasserts control of the weather over the UK later.

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKM & ECM The current verification statistics for the past 31 days shows ECM leading the way at 3 days with 97.4 pts followed by UKM at 96.9 pts and GFS at 96.2. At 5 days ECM just about leads the field at 89.8 pts over UKMO at 89.2 pts and GFS at 86.9. At 8 days ECM remains the leader with 62.4 pts over GFS's 62.0 pts. Then at Day 10 ECM retains superiority at 46.5 pts over GFS at 43.5.

http://www.emc.ncep....L_MSL_G2NHX.png

http://www.emc.ncep....L_MSL_G2NHX.png

http://www.emc.ncep....L_MSL_G2NHX.png

http://www.emc.ncep...._MSL_G2NHX.prig
 

MY THOUGHTS The pattern of weather across the UK remains dictated to by the behaviour of High pressure areas in the vicinity of the British Isles over the coming two weeks. There is of course the marked period of more unsettled conditions lasting 4-5 days when all areas will see some rain and showers for a time before all models show High pressure returning in some shape or form later. The position of this remains fluid at the moment but most place it close to Southern Britain with any further unsettled weather in the second half of the period likely to be across the North as SW , West or NW winds blow while the South stays rather quieter. Temperature levels look unlikely to be bothersome in terms of lowness with frost amounts only occasional as and when cloud breaks under the High pressure occurs later and behind any cold fronts which pass over the North briefly. It should also be mentioned that if the SW flow that some output verifies then temperatures will shoot above average especially in the sheltered East. So in summary a short spell of cloudier and winder weather with rain at times will be replaced by better weather again as High pressure lies close to the South. Northern areas may see occasional rain or showers in a more blustery West wind and conditions generally will never be that cold.  

Issued at 08:30 Wednesday February 11th 2015


Martin G
Kilmersdon Radstock Bath Somerset



Look up my New Facebook Weather Page  for all the latest up to the minute weather stories as they happen
Hippydave
11 February 2015 09:20:24

There's a few tentative signs in the GFS ens of some colder weather to end the month, present on both the Aberdeen and London sets. The former has a few snow givers in there too.


Too far out for much notice but worth keeping an eye on to see if the trend moves closer.


ECM240 also hints at a more amplified pattern with HP ridging North, which could bring at least some transient cooler weather too.


All that said and nearer term then as Gibby has said, a brief unsettled blip before HP returns - given the air source and where it sets up it'll probably be of the cloudy and mildish variety unless any cooler, clearer air gets dragged in to it.


Before I get jumped on I'll also mention that if the cooler FI signal does continue, a Northerly flow down South late Feb often feels very pleasant out of the wind and in the sun - probably much more so than a dank cloudy HP 


Perhaps the Southern mildies should be rooting for an end of month Northerly incursion


Home: Tunbridge Wells
Work: Tonbridge
David M Porter
11 February 2015 10:04:17

IIRC the exceptionally cold March in 2013 came on the back of a spell of HP domination that occurred in mid-late February. I'm not syaing that anything like that will happen this time, but if HP does dominate for the rest of the month as the models seem to be indicating and then heights rise to the north later, another cold spell cannot be ruled out, even if it isn't like a couple of years ago.


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
nsrobins
11 February 2015 11:18:32


IIRC the exceptionally cold March in 2013 came on the back of a spell of HP domination that occurred in mid-late February. I'm not syaing that anything like that will happen this time, but if HP does dominate for the rest of the month as the models seem to be indicating and then heights rise to the north later, another cold spell cannot be ruled out, even if it isn't like a couple of years ago.


Originally Posted by: David M Porter 


March 2013 aside, very late season northerly shots are normally next to useless in the South, both in terms of lying snow and temperatures. Further North it can be a different story, but the synoptics have to be pretty much spot on to deliver.


Most of us if we were honest are thinking in terms of putting winter to bed and moving on to warmth and decent convection by then anyway.


Neil
Fareham, Hampshire 28m ASL (near estuary)
Stormchaser, Member TORRO
Brian Gaze
11 February 2015 11:31:31


 


March 2013 aside, very late season northerly shots are normally next to useless in the South, both in terms of lying snow and temperatures. Further North it can be a different story, but the synoptics have to be pretty much spot on to deliver.


Most of us if we were honest are thinking in terms of putting winter to bed and moving on to warmth and decent convection by then anyway.


Originally Posted by: nsrobins 


I agree. Spring and summer can't come soon enough now and fortunately events like March 2013 are very rare and I'd put money on us not having a repeat this year. 


Brian Gaze
Berkhamsted
TWO Buzz - get the latest news and views 
"I'm not socialist, I know that. I don't believe in sharing my money." - Gary Numan
Gooner
11 February 2015 13:53:25

No chart available for the selected hour. Many charts start at 3 hours ahead, so if you have 0 hours selected try stepping forward or selecting a later hour.


Several runs edging down towards months end


Remember anything after T120 is really Just For Fun



Marcus
Banbury
North Oxfordshire
378 feet A S L


moomin75
11 February 2015 14:31:01


No chart available for the selected hour. Many charts start at 3 hours ahead, so if you have 0 hours selected try stepping forward or selecting a later hour.


Several runs edging down towards months end


Originally Posted by: Gooner 

Perfect. Just in time for spring!


Witney, Oxfordshire
100m ASL
SEMerc
11 February 2015 17:06:03


 


I agree. Spring and summer can't come soon enough now and fortunately events like March 2013 are very rare and I'd put money on us not having a repeat this year. 


Originally Posted by: Brian Gaze 


Yep, winter is fast disappearing into fantasy land, alongside finding oneself in a room with Christina Hendricks and taking her bra off.

nsrobins
11 February 2015 17:20:15


 


Yep, winter is fast disappearing into fantasy land, alongside finding oneself in a room with Christina Hendricks and taking her bra off.


Originally Posted by: SEMerc 



I see what you mean. Model-watching still has it's place IMO
Swerving majestically back on topic, and I wonder what effect the 12Z GFS OP from +336 would have in here were it to appear closer than +120. I hazard a guess it would have a similar effect as the above image is having just now


Neil
Fareham, Hampshire 28m ASL (near estuary)
Stormchaser, Member TORRO
Quantum
11 February 2015 18:34:41

Can't believe there arn't any jokes about the GEM 12Z run.


 


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
11 February 2015 18:43:41


Nothing wrong with that Q


Remember anything after T120 is really Just For Fun



Marcus
Banbury
North Oxfordshire
378 feet A S L


sizzle
11 February 2015 19:05:52

if we stay on topic, this thread will last till march    I see east side of the states are enjoying a nice deep freeze,

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