Quantum
27 March 2020 15:43:43

The ICON12z is looking downright 2010ian.


 


Twitter: @QuantumOverlord (general), @MedicaneWatch (medicane/TC stuff)
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.
tallyho_83
28 March 2020 01:26:55

Surprised the Zonal winds @ 10hpa are so strongly positive over top of N. Pole and set to stay this way, - given the SSW:


Even when it weakens it will stay stronger than average!?



Home Location - Kellands Lane, Okehampton, Devon (200m ASL)
---------------------------------------
Sean Moon
Magical Moon
www.magical-moon.com


doctormog
28 March 2020 06:38:27

Do you get zonal winds at the North Pole? 


(I am assuming you're not referring to the chart above.)


Col
  • Col
  • Advanced Member
28 March 2020 06:45:18

Originally Posted by: doctormog 


Do you get zonal winds at the North Pole? 


(I am assuming you're not referring to the chart above.)



They're always southerlies :)


Col
Bolton, Lancashire
160m asl
Snow videos:
http://www.youtube.com/channel/UC3QvmL4UWBmHFMKWiwYm_gg
doctormog
28 March 2020 06:49:07

Originally Posted by: Col 


 


They're always southerlies :)



Indeed. 


DEW
  • DEW
  • Advanced Member
28 March 2020 07:19:55

The jetstream cnanges today from running the N of the UK to throwing a loop with strong N-ly down the N Sea which gradually weakens and moves back to its original position by Tue 31st, by then not at all strong but instead an impressive broad jet through the Med developing and taking over until Thu 9th. That then moves N and strengthens over France before resuming across the UK by Mon 13th


GFS starts with HP 1050mb near Iceland, slipping S with a ridge cutting off the worst of the N/NE-lies by Thu 2nd, Scotland then gets a glancing blow from fresh Arctic incursion (LP near Norway) but by Mon 6th HP has moved to France with mild S-lies for all. That then weakens and allows Atlantic LP to approach Thu 9th with secondary running up the Channel, but the main centre keeps out to the NW with zonal W-ly from Sat 11th


ECM similar but LP 5th/6th is deeper and S-lies rather strong and cooler esp in the west.


GEFS ens runs for the S cold to Mon 30th, cool and slowly back to seasonal norm by Mon 6th, then mild for most but with a few startling very cold outliers. (the mildest run in the S is 8C above norm on the same day as the coldest is 9C below!). Rain begins again around Tue 7th. Scotland a bit different, temps recover quickly after 30th, but have a second dip before back to norm on Mon 6th, and more scatter after that with fewer mild runs and rain from 5th, not 7th. NW England like the S, NE England more like Scotland.


 


War does not determine who is right, only who is left - Bertrand Russell

Chichester 12m asl
DEW
  • DEW
  • Advanced Member
29 March 2020 06:58:07

It looks a lot warmer in week 2 and very dry http://www.wxmaps.org/pix/temp4. Noe for the detailed stuff:


GFS - HP slipping S this week with ridge to Europe while Scotland gets a glancing blow from cold air on the back edge of LP over Scandi Sat 4th. Then HP re-asserts itself from the S with S-ly winds winds for all and eventually comes to rest Sat 11th 1035mb over UK, and looking very warm. By end of run Tue 14th this has linked with the Azores High.


ECM spreads the cold air on the 4th further S & E and is slower to develop the S-ly but in outline the same.


FAX (only up to the 2nd) makes the cold incursion likely to be much more widespread and stronger.


GEFS for the S runs agree to temps steadily recovering to seasonal norm by Sun 5th, and the majority averaging 5C above that to Tue 14th (but I note just one rogue run  10C below on the 8th!) Some rain around Tue 7th - Thu 9th and  small amounts after that (not entirely agreeing with models above).


For Scotland, the recovery to the norm is not as smooth as in the S, and there is noticeably less agreement between runs after that with some wide divergence between warm and cold and several of each to choose from. Rain likely to begin around the 5th.


As yesterday, NW England is more like the S and NE more like Scotland, but both occupying an intermediate position.


 


War does not determine who is right, only who is left - Bertrand Russell

Chichester 12m asl
nsrobins
29 March 2020 08:50:56
The dreaded shortwave looks to have finally killed the chances of a decent polar northerly next weekend.
Nice to know in these uncertain times some things don’t change. 😊

Neil
Fareham, Hampshire 28m ASL (near estuary)
Stormchaser, Member TORRO
doctormog
29 March 2020 09:00:08

Originally Posted by: nsrobins 

The dreaded shortwave looks to have finally killed the chances of a decent polar northerly next weekend.
Nice to know in these uncertain times some things don’t change. 😊


It is still too close to here for my liking but hopefully the recent trend will continue.


Quantum
29 March 2020 16:51:12

Well those are some uppers arn't they!



Twitter: @QuantumOverlord (general), @MedicaneWatch (medicane/TC stuff)
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
29 March 2020 16:52:17

Originally Posted by: nsrobins 

The dreaded shortwave looks to have finally killed the chances of a decent polar northerly next weekend.
Nice to know in these uncertain times some things don’t change. 😊


ICON doesn't have it at all.


ICON is also higher resolution....


Twitter: @QuantumOverlord (general), @MedicaneWatch (medicane/TC stuff)
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
29 March 2020 17:49:44


Fun chart for Shetland.


Very good rule of thumb. An 850hpa temp below -14C guarantees the surface temp remaining below freezing regardless of the time of year.


 


Twitter: @QuantumOverlord (general), @MedicaneWatch (medicane/TC stuff)
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.
Gusty
29 March 2020 17:53:36

Originally Posted by: Quantum 



Fun chart for Shetland.


Very good rule of thumb. An 850hpa temp below -14C guarantees the surface temp remaining below freezing regardless of the time of year.


 



An 850Hpa temperature of -10c didn't stop us achieving a max of 8.2c here today. 


Steve - Folkestone, Kent
Current conditions from my Davis Vantage Vue
https://www.wunderground.com/dashboard/pws/IFOLKE11 
Join Kent Weather on Facebook.
https://www.facebook.com/stevewall69/ 



Quantum
29 March 2020 18:35:37

Originally Posted by: Gusty 


 


An 850Hpa temperature of -10c didn't stop us achieving a max of 8.2c here today. 



-14C is a very different beast to -10C!


 


Twitter: @QuantumOverlord (general), @MedicaneWatch (medicane/TC stuff)
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.
Whether Idle
29 March 2020 18:36:27

Well, personally I hope the GFS is picking up the right scent as it has the HP more dominant than UKMO and ECM for next weekend.


WI



Dover, 5m asl. Half a mile from the south coast.
Tim A
29 March 2020 19:23:07
With such temperature contrasts north to south there could be a good battleground somewhere, looks like the far north at the moment but ECM pulls colder air further south .
Tim
NW Leeds
187m asl


Phil G
29 March 2020 21:15:36
Might be my untrained eye but sure ECM has backtracked or delayed the milder push from the south. Another HP wants to bring in an easterly of sorts at 240.
BJBlake
29 March 2020 22:23:57
That dart board mid Atlantic high brought a few flakes of snow in the showers today, but the trend is for the Titan zonal express to rage again, which is unusual at this time of year. However, looking back a couple of weeks this was the trend back then, only to change last week to a colder rinse and repeat situation, but now it's anyone's call. My money is on the mild winning out and any battle taking place in Shetland.
Brecklands, South Norfolk 28m ASL
DEW
  • DEW
  • Advanced Member
30 March 2020 06:00:57

The branch of the jetstream pushing down the N Sea gives up by Wed 1st with weaker W-E flow to N of UK while broad and strong jet develops across the Med. That northern branch persists longer than forecast a couple of days ago when I last looked, and the one from the Med weakens, too. Eventually the latter drifts north ca Fri 10th to run across the UK and continues so in a rather fragmented way to Wed 15th (but keep an eye on the really strong jet then leaving Newfoundland)


On the GFS this translates to Mid Atlantic HP with ridge to Europe Wed 1st, then slack for a bit with new HP over W Europe by Sun 5th with S-lies in place.This HP wanders around a bit with LP from Atlantic always threatening a breakthrough, but only doing so Tue 14th. The following day there's 965mb mid-Atlantic - being fed by the above jet?


ECM (sorry, 12z, haven't got time to wait for 0z today) brings cold air S on Sat 4th which GFS diverts further E, then develops the HP as above but with ridge to Iceland so although we get S-lies, N-lies are only just across the N Sea.


FAX also likes a brief N-ly incursion, but earlier, on Thu 2nd before new HP the next day


GEFS like yesterday, in S temps recovering to seasonal norm by Sun 5th then mild (very mild at first) for majority of runs. Dry then more chance of rainfall from Wed 8th. Similar in N, but temp runs diverge more and rain possible a day or two earlier. Not sure where the rain is coming from, looking at the synoptics. perhaps some runs do achieve an Atlantic breakthrough.


 


War does not determine who is right, only who is left - Bertrand Russell

Chichester 12m asl
johncs2016
30 March 2020 07:15:00

From what I can see, the outlook is starting to look more zonal once again as we head into April with virtually all hints of northern blocking appearing to have disappeared from the last model output, at least for the foreseeable future.

Can I assume from this, that there will therefore be no tropospheric response to the recent SSW event which was just occurred, or was this little cold blip which has resulted in a few places getting a few snow showers over recent days, that response? If the latter case is true, I would have thought that this is probably far too soon to get such a response which to me, tells me that there aren't really any signs of such a response occurring at all.


The north of Edinburgh, usually always missing out on snow events which occur not just within the rest of Scotland or the UK, but also within the rest of Edinburgh.
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